Objective: To analyze maternal deaths, identify causes and dysfunctions leading to these deaths in order to contribute to the implementation of strategies to reduce maternal mortality at CHU Kara. Method: Cross-sectio...Objective: To analyze maternal deaths, identify causes and dysfunctions leading to these deaths in order to contribute to the implementation of strategies to reduce maternal mortality at CHU Kara. Method: Cross-sectional descriptive study involving 65 cases of maternal deaths recorded at CHU-Kara from January 1, 2018 to June 30, 2021. Results: Our study focused on 65 cases of maternal deaths recorded at the maternity ward of CHU-Kara. The average age was 30 years, with a range of 15 to 45 years. They were mostly housewives (52.3%), uneducated (38.5%), multiparous (41.5%), and referred (86.2%). The causes were mainly direct obstetric causes (81.54%), with preeclampsia and its complications (28.30%) and immediate postpartum hemorrhage (20.75%) being the most common. However, uterine rupture (20.5%) and post-abortion sepsis (16.4%) were the most lethal etiologies. Delayed evacuation (46.43%), inadequate transportation (91%), and insufficient prenatal care (72.31%) were the dysfunctions before referral. Within the CHU Kara, delays in management (58.46%), unavailability of blood and labile products (18%), and insufficient monitoring were the dysfunctions identified. Ninety-five point four percent (95.4%) of the deaths were preventable. Conclusion: The magnitude of intrahospital maternal deaths, the various dysfunctions observed in the occurrence of maternal deaths before referral/evacuation and within the hospital highlight the importance of effectively implementing recommendations from audits in the fight against maternal mortality. The majority of the deaths were preventable (95.38%).展开更多
Introduction: Obstetric emergencies are common throughout the world and more particularly in developing countries where they are responsible for high maternal-fetal mortality and morbidity. Objective: Study obstetric ...Introduction: Obstetric emergencies are common throughout the world and more particularly in developing countries where they are responsible for high maternal-fetal mortality and morbidity. Objective: Study obstetric emergencies in the maternity ward of Kara University Hospital. Method: Retrospective and descriptive study from April 1, 2022 to March 30, 2023, carried out in the Obstetrics and Gynecology Department of Kara University Hospital. Results: Eight hundred and thirty-five (835) obstetric emergencies were recorded out of 2215 admissions, i.e. a frequency of 37.7%. The average age of the patients was 26.7 with a range of 14 and 45 years. They were primigravidas (36.7%) and nulliparous (38.7%), referred (84.7%) and came from rural areas (72%). Emergencies occurred in the 3<sup>rd</sup> trimester in 74.1% and in parturients (54.1%). Preeclampsia (27%), cessation of progression of labor due to feto-pelvic disproportion (12.4%), postpartum hemorrhage (7.5%) constituted the main obstetric emergencies. In 44.8%, the delivery was carried out vaginally. Magnesium sulfate was the most used drug, i.e. 30.1%;followed by antihypertensive medications in 28.1%. Blood transfusion was performed in 24.3%. The evolution was simple in 90.9%. The maternal fatality rate was 1.6%. The perinatal case fatality rate was 12.3%. Conclusion: Obstetric emergencies are common, dominated by preeclampsia, stopping progress of labor and postpartum hemorrhages. They are responsible for high morbidity and mortality.展开更多
Introduction: Endoscopic internal urethrotomy (EIU) is a method for stricture opening using transurethral incision by direct visualisation of the urethral channel, resulting in a widening of the urinary canal with the...Introduction: Endoscopic internal urethrotomy (EIU) is a method for stricture opening using transurethral incision by direct visualisation of the urethral channel, resulting in a widening of the urinary canal with the aim of improving the quality of bladder emptying. The aim of the study was to evaluate the indication and results of EIU in the treatment of stenosis of the male urethra in the Urology-Andrology Department of Kara Teaching Hospital. Methodology: This was a cross-sectional descriptive study with retrospective data collection in the Urology-Andrology department of Kara Teaching Hospital. It involved 21 records of patients with urethral stenosis treated by endoscopic internal urethrotomy (EIU) in the said department during the period from January 2021 to September 2023. The following variables were evaluated: age, circumstance of discovery, site, length, number, etiology of the urethral stenosis and evolution of the patients. Results: The mean age of the patients was 59.2 ± 11.7 years. Infectious etiology of stenosis was predominant with 10 patients (47.6%) followed by trauma with 5 cases (23.8%). The bulbar urethra was the most frequently observed site, with 11 cases (52.4%). The length was mostly less than 2 cm in 12 patients (57.1%). Stenosis was unique in 14 patients (66.7%). The mean postoperative follow-up time was 3.2 months. The result was immediately better in 11 patients (52.4%) and it was poor in 8 patients (38.1%) who required maintenance dilation sessions.展开更多
Introduction: Viral hepatitis B and C constitute real public health problems worldwide. The objective of this work was to describe the epidemiological, clinical and paraclinical aspects of viral hepatitis B and c in t...Introduction: Viral hepatitis B and C constitute real public health problems worldwide. The objective of this work was to describe the epidemiological, clinical and paraclinical aspects of viral hepatitis B and c in the internal medicine department of Kara University Hospital. Method: this was a retrospective descriptive study carried out in the Internal Medicine department of Kara University Hospital, over a period of 3 years from March 2020 to April 2023. It included all patients seen in consultation or hospitalized for hepatitis viral B and/or C. Results: A total of 57 patients were included in our study. The average age was 44.30 years ± 16.75 and the M/F sex ratio was 1.38. Married people were in the majority 63.2%. The circumstances of the discovery of viral hepatitis B and C were dominated by abdominal pain in 35.1% of cases and hepatomegaly in 29.8% of cases and in 33.3% of cases, it was during screening voluntary. Patients with viral hepatitis B only accounted for 64.9% of cases;those with only viral hepatitis C represented 31.6% of cases and 3.5% of cases had HVB/HCV co-infection. We recorded 36.8% complications including 52.4% liver cirrhosis and 47.6% hepatocellular carcinomas. During the evolution, there were 03 deaths. Conclusion: the prevalence of hepatitis B and C virus carriage in patients followed in internal medicine at Kara University Hospital is high. It is therefore essential to put in place treatment and prevention strategies against these viruses.展开更多
A 606 year runoff reconstruction of the Kara Darya River was developed, based on the tree-ring width chronology of Turkestan juniper(Juniperus turkestanica) from the Pamir-Alai Mountains of Kyrgyzstan. Preliminary com...A 606 year runoff reconstruction of the Kara Darya River was developed, based on the tree-ring width chronology of Turkestan juniper(Juniperus turkestanica) from the Pamir-Alai Mountains of Kyrgyzstan. Preliminary comparison between the snow cover variation and these climate/runoff reconstructions found that Central Asian snow cover may have strong associations with large-scale ocean-atmosphere-land circulations. The runoff reconstruction demonstrated that instrumental runoff was not representative of runoff over the past 606 years. The drought of the 1960 s-1990 s resulted in low runoff levels during the past 50 years;however, this probably does not represent a worst-case scenario for the Kara Darya because the runoff reconstruction showed additional extremely low runoff prior to the 20 th century. The reconstruction will provide a long-term perspective on runoff variation in the Kara Darya River basin, aid sustainable water resource management and be useful in guiding expectations of future variations and water resource planning.展开更多
This study investigated atmospheric responses in mid late winter and early spring to sea ice loss in the Barents and Kara seas using regressions of the January March mean atmosphere on Barents and Kara sea ice area in...This study investigated atmospheric responses in mid late winter and early spring to sea ice loss in the Barents and Kara seas using regressions of the January March mean atmosphere on Barents and Kara sea ice area in November and December.Similar atmospheric circulation responses were obtained from reanalysis data and multimodel ensemble results from the Coupled Model Intercomparison Project Phase 5,i.e.,sea ice anomalies are the dominant factor driving the overlying atmosphere.The results showed that an Arctic Asia dipole structure,with opposite anomalies over the mid-latitudes of Asia and over the adjoining Arctic,appears to be the key atmospheric circulation anomaly influencing the East Asian climate in mid late winter and early spring.展开更多
In the Arctic (mainly in its European sector) there is statistically detectable seasonal reversal wind pattern. The combination of seasonally warm (cold) land surfaces in arctic areas together with cool (cool) sea sur...In the Arctic (mainly in its European sector) there is statistically detectable seasonal reversal wind pattern. The combination of seasonally warm (cold) land surfaces in arctic areas together with cool (cool) sea surface of Arctic seas not covered by ice is conducive to the formation of a monsoon like system. On the other hand, the predominance of the cyclonic regime during all seasons makes it difficult to answer the question of whether the Arctic region belongs to the monsoon type pattern. In this study, the monsoon features of atmospheric circulation over the Barents and Kara Seas were analysed. To extract specific monsoon signs, atmospheric circulation systems (separately for areas of each sea) were divided into ten weather types. Their appearance and statistics were compared with indicators of regional circulation. A significant part of intra-annual monsoon variability is associated with the configuration of such modes as the North Atlantic Oscillation and the <em>Scandinavia</em> teleconnection patterns. For example, during the winter season, the monsoon currents (from land to sea) occur only with a positive North Atlantic Oscillation index. With the prevalence of other modes of variability, the direction of the winds can be different, and the regular monsoon circulation pattern is changed by chaotic regime. In summer, northern streams (from sea to land) are realized on the western periphery of cyclones, regenerating and stabilizing over the Kara Sea. As for anomalies, the nature of the monsoons is manifested in the statistics of extreme winds even without selecting data on the regimes of variability. So, in winter, maximum speeds fall on the southern streams, and in the summer—on the northern ones. Large precipitation anomalies during all seasons, as one would expect, are encountered most often with the cyclonic type of circulation.展开更多
Nonlinear internal waves(NIWs) are ubiquitous around the Kara Sea, a part of the Arctic Ocean that is north of Siberia. Three hot spot sources for internal waves, one of which is the Kara Strait, have been identified ...Nonlinear internal waves(NIWs) are ubiquitous around the Kara Sea, a part of the Arctic Ocean that is north of Siberia. Three hot spot sources for internal waves, one of which is the Kara Strait, have been identified based on Envisat ASAR. The generation and evolution of the NIWs through the interactions of the tide and topography across the strait is studied based on a nonhydrostatic numerical model. The model captures most wave characteristics shown by satellite data. A typical inter-packets distance on the Barents Sea side is about 25 km in summer, with a phase speed about 0.65 m/s. A northward background current may intensify the accumulation of energy during generation, but it has little influence on the other properties of the generated waves. The single internal solitary wave(ISW) structure is a special phenomenon that follows major wave trains, with a distance about 5–8 km. This wave is generated with the leading wave packets during the same tidal period. When a steady current toward the Kara Sea is included, the basic generation process is similar, but the waves toward the Kara Sea weaken and display an internal bore-like structure with smaller amplitude than in the control experiment. In winter, due to the growth of sea ice, stratification across the Kara Strait is mainly determined by the salinity, with an almost uniform temperature close to freezing. A pycnocline deepens near the middle of the water depth(Barents Sea side), and the NIWs process is not as important as the NIWs process in summer. There is no fission process during the simulation.展开更多
Sea ice is the predominant natural threat to marine structures and oil-gas exploitation in the Arctic.However,for ice-resistant structural design,long-term successive level ice thickness measurements are still lacking...Sea ice is the predominant natural threat to marine structures and oil-gas exploitation in the Arctic.However,for ice-resistant structural design,long-term successive level ice thickness measurements are still lacking.To fill this gap in the southern Kara Sea,the Los Alamos Sea Ice Model(CICE)is applied to achieve better simulation at the local and regional scales.Based on the validation against ice thickness observations in March and April in 1980-1986,the statistical root-mean-square error is determined to be less than 0.2 m.Then,based on the hindcast data,the spatiotemporal distributions of level ice thickness are analyzed annually,seasonally,and monthly,with thicker level ice of 1.2-1.5 m in spring and large ice-free zones in September and October.For floating platforms,a novel ice grade criterion with five classifications,namely,excellent,good,moderate,severe,and catastrophic,is pro-posed.The first two grades are most suitable for offshore activities,particularly from August to October,and the moderate grade is acceptable if with ice-resistant protections.Furthermore,hostile ice conditions are discussed in terms of the generalized extreme value distribution.The statistics reveal that at a return period of 100 yr,extreme level ice is primarily between 0.6 m and 1.0 m in December.The present investigation could be a useful reference for a feasibility study of the potential risk analysis and ice-resistant operation of oil-gas exploitation in the Arctic.展开更多
The sea ice conditions in the Kara Sea have important impacts on Arctic shipping,oil and gas production,and marine environmental changes.In this study,sea ice coverage(C_(R))less than 30%is considered as open water,it...The sea ice conditions in the Kara Sea have important impacts on Arctic shipping,oil and gas production,and marine environmental changes.In this study,sea ice coverage(C_(R))less than 30%is considered as open water,its onset and end dates are defined as T_(open)and T_(close),respectively.The sea ice melt onset(T_(melt))is defined as the date when ice-sea freshwater flux initially changes from ice into the ocean.Satellite-based sea ice concentration(SIC)from 1989 to 2019 shows a negative correlation between T_(open)and T_(close)(r=-0.77,p<0.01)in the Kara Sea.This phenomenon is also obtained through analyzing the hindcast simulation from 1994 to 2015 by a coupled ocean and sea-ice model(NAPA1/4).The model results reveal that thermodynamics dominate the sea ice variations,and ice basal melt is greater than the ice surface melt.Heat budget estimation suggests that the heat flux is significant correlated with T_(open)(r=-0.95,p<0.01)during the melt period(the duration of multi-year averaged T_(melt)to T_(open))influenced by the sea ice conditions.Additionally,this heat flux is also suggested to dominate the interannual variation of the heat input during the whole heat absorption process(r=0.81,p<0.01).The more heat input during this process leads to later T_(close)(r=0.77,p<0.01).This is the physical basis of the negative correlation between T_(open)and T_(close).Therefore,the duration of open water can be predicted by T_(open)and thence support earlier planning of marine activities.展开更多
<strong>Background:</strong> Ocular coloboma is the product of an error in the fetal fissure closure, normally occurring between the fifth and sixth weeks of gestation <a href="#R1" target=&qu...<strong>Background:</strong> Ocular coloboma is the product of an error in the fetal fissure closure, normally occurring between the fifth and sixth weeks of gestation <a href="#R1" target="_blank">[1]</a>. It may involve the cornea, iris, zonula, ciliary body, choroid, retina and optic nerve. The incidence of this syndrome is 0.7 per 10,000 live-births <a href="#R1" target="_blank">[1]</a>. The aim of this observation is to present the first case of bilateral coloboma of the iris <a href="#R1" target="_blank">[1]</a>. This case was associated with an ametropia causing a decrease in visual acuity. <strong>Case Presentation:</strong> This was a clinical observation concerning a young 12-year-old patient who consulted for blurring of vision which had progressed for approximately 2 years. The ophthalmologic examination revealed an ametropia with a bilateral notch of the pupillary rim suggesting a bilateral coloboma. There was no association with another coloboma such as chorioretinal coloboma which is quite common and is accompanied frequently by visual symptoms. <strong>Conclusion:</strong> A visual impairment of the child can indicate ametropia. However, other congenital anomalies can be discovered as was the case in this clinical observation.展开更多
Background: The urology department of the Teaching Hospital of Kara is the 2nd urology department in Togo, Kara being a semi-urban town located 400 km from Lomé the capital. While for a long time only open surger...Background: The urology department of the Teaching Hospital of Kara is the 2nd urology department in Togo, Kara being a semi-urban town located 400 km from Lomé the capital. While for a long time only open surgery was used, the acquisition of urological endoscopic equipment in February 2021, has revolutionized the urological management of patients. Objective: Report the results of the first 15 months of urological endoscopy practice at the Kara Teaching Hospital, identify the particularities, announce the prospects. Patients and Methods. This was a retrospective and descriptive study, which took place in the urology department of the Kara Teaching Hospital, from February 2021 to April 2022, i.e. a period of 15 months. The register of operative reports and patient records were used for data collection. The following parameters were studied: age, sex, diagnosis, indication, diagnostic or therapeutic nature of the procedure, and results. EPI INFO 7.2.4.0 software was used for data analysis. Results: A total of 102 urological procedures (endoscopic and non-endoscopic) were performed during the study period;of the 102 interventions, 62 were endoscopic urological interventions, i.e., 60.7% of the interventions. The average age of patients treated was 55.5 years (±16.4) with extremes ranging from 28 to 87 years. Men accounted for 84% of patients treated. Prostatic hypertrophy was the most common urological pathology in our study, requiring endoscopic intervention in 40% of cases. Transurethral resection of the prostate was the most performed endoscopic procedure in our study with 43.5% of cases. The various endoscopic interventions resulted in success in 96.7% of cases. Conclusion: Urology nowadays cannot be done without endoscopy. At the Kara Teaching Hospital, the results are already promising after less than 24 months of endoscopic practice in urology. Advocacy must be made to political decision-makers, so that the situation is even better, for the good of both urologists and patients.展开更多
Background: The urology department of the teaching hospital of Kara is the second urology department in Togo, after that of the teaching hospital Sylvanus Olympio, in Lomé the capital. It is a very young service,...Background: The urology department of the teaching hospital of Kara is the second urology department in Togo, after that of the teaching hospital Sylvanus Olympio, in Lomé the capital. It is a very young service, created less than 5 years ago. Urological emergencies were previously managed by general surgeons, for lack of urologists. The influx of patients with urological pathologies has increased with the arrival of urologists. The update on urological emergencies having been made in Lomé, we therefore wanted to take stock of urological emergencies at the teaching hospital of Kara. Objective: To describe the epidemiological, clinical, and therapeutic aspects of urological emergencies received at the teaching hospital of Kara. Patients and Methods: This was a descriptive study with retrospective data collection. The study took place in the urology department, and in the surgical emergency department of the teaching hospital of Kara, over a period of 18 months, from January 2021 to June 2022. The on-call medical team consisted of the intern in on-call medicine, and an on-call urologist, whom the intern called upon when he received a urological emergency. Pediatric urological emergencies were managed by the pediatric surgeon and were not considered in our study. The operating room register, the surgical emergency consultation register, the urology department consultation register, and the records of patients hospitalized in the urology department were used for data collection. The following parameters were studied: age, sex, type of urological emergency, and therapeutic management;epi info 7 software was used for data processing. Results: The average age of the patients was 52.5 ± 19.6 years with extremes ranging from 16 years to 102 years. Note that 57.7% of the patients were over 50 years old. The sex ratio was 8.9. Urinary retention was the most common urological emergency in 47.7% (52) of cases;follow-up of infectious pathologies in 30.2% (33) of cases. Among the patients who had been seen for urinary retention, 84.6% (44) of the cases had presented with acute urinary retention. Urethral catheterization was the type of care most received by patients, in 30.2% (33) of cases;follow-up of medical treatment in 27.5% (30) of cases. The most common etiology of urinary retention was prostate tumours, in 71.1% (37) of cases, followed by urethral stricture in 15.3% (8) of cases. We also found in our series, traumatic emergencies in 10% of cases;these were traumatic urethral injuries, traumatic injuries of external genitalia, traumatic injury of bladder, and traumatic injury of kidney in respectively: 4.5% (5);2.7% (3);1.8% (2);and 0.9% (1) of cases. Torsion of the spermatic cord was found in 2.7% (3) of cases. Conclusion: Urine retention is the most common urological emergency at Kara University Hospital. They are most often found in elderly males. Urethral catheterization was the most common type of care.展开更多
Introduction: cervical cancer is common with high mortality. It is diagnosed late in developing countries. Reducing mortality requires better knowledge and screening for cervical cancer. Objective: To study the knowle...Introduction: cervical cancer is common with high mortality. It is diagnosed late in developing countries. Reducing mortality requires better knowledge and screening for cervical cancer. Objective: To study the knowledge, attitudes and practices of midwives in the Kara region of cervical cancer screening. Methods: Cross-sectional, descriptive study from January 2020 to June 2020 conducted with midwives from the Kara region. Results: Fifty midwives participated in the study. The average age was 32.46 years and the majority (92%) had less than 10 years work experience. Thirty seven (74%) said that cervical cancer was due to human papillomavirus oncogenes and 32% to know the two commonly used screening methods (cervical cytology and VIA/VILI). Only 30% and 8% respectively know the pace and target of screening. They had all expressed the desire to be trained and to carry out routine screening. All of the respondents had never practiced a cervical cytology, and only 01 had once practiced VIA/VILI. Conclusion: Midwives have little knowledge of uterine cancer screening and do not practice it. They express the need to be trained in order to popularize the practice.展开更多
Background: Urethral stricture is a pathology frequently encountered in urological practice. Management is often surgical, with possible recurrences. What about this pathology in Kara, a semi-urban city? Objective: As...Background: Urethral stricture is a pathology frequently encountered in urological practice. Management is often surgical, with possible recurrences. What about this pathology in Kara, a semi-urban city? Objective: Assess the management of male urethral stricture in Kara. Patients and Methods: This was a descriptive study with retrospective data collection. The study took place in the urology department of the teaching hospital of Kara, from December 2020 to December 2022. All cases of male urethral stricture, surgically treated at the teaching hospital of Kara, were listed. The inclusion criteria were as follows: any patient who had been treated surgically for male urethral stricture in the urology department of the teaching Hospital of Kara. The operating theater register and hospital records were used to collect the data. The diagnosis of urethral stricture had been made with retrograde urethrogram. A total of 24 patients were treated for male urethral stricture during the study period. The following variables were studied: age, reason for consultation, location, length, and etiology of the stricture;the type of treatment received: optical internal urethrotomy, or anastomotic urethroplasty, and the results. The result was considered good if, after removal of the urethral catheter, the patient regained his micturition without the need for dilatation;the result was considered average if, after removal of the urethral catheter, the patient needed one or more dilatation sessions to regain urination;the result was considered poor if, after removal of the catheter, the patient did not regain good micturition despite the urethral dilatation sessions. Microsoft excel and epi info 7 software were used for data processing. Results: The average age of our patients was 43.7 years ± 10.18 with extremes ranging from 27 to 70 years. The most represented age groups were that of 40 to 50 years, with 37.5% of cases;and that of 30 to 40 years with 33.3% of cases. The patients had consulted for urine retention in 66.6% of cases;the location of urethral stricture was bulbar in 45.8% of cases. The most found etiology was infectious in 58.3% of cases. Among our patients, 58.3% had received optical internal urethrotomy as treatment, while 41.6% of our patients had received anastomotic urethroplasty as treatment. Postoperatively, after removal of the urinary catheter, 87.5% of patients had benefited from one or repeated dilatation. In terms of results, we had a good result in 20.8% of patients;the result was average in 45.8% of patients, and poor in 33.3% of patients. The average duration of follow-up was 14.3 +/- 7.2 months (3-27). Conclusion: Male urethral stricture mainly affects young adults in Kara. Surgical management is done by optical internal urethrotomy and/or anastomotic urethroplasty.展开更多
<strong>Objectives:</strong> To evaluate the practice of self-care in diabetic patients monitored at the Kara Teaching Hospital, known as CHU Kara. <strong>Method:</strong> We conducted a quant...<strong>Objectives:</strong> To evaluate the practice of self-care in diabetic patients monitored at the Kara Teaching Hospital, known as CHU Kara. <strong>Method:</strong> We conducted a quantitative, descriptive and cross-sectional study of 40 diabetic patients monitored at the Kara CHU. The data collection took place from February 20 to May 28, 2018 and the data was collected anonymously. <strong>Results:</strong> Out of the forty (40) respondents, 60% were male with a sex ratio of 1.5 and an average age of 56.15 years. Two-thirds (2/3) of the patients did not have the blood glucose meter. More than half (52%) did not know the normal blood glucose value and 82.5% were on a low carbohydrate diet. Eighty-two point fifty percent (82.50%) were under Oral antidiabetic (ADO). Forty percent (40%) of patients often forgot their medication. Forty-seven point-fifty percent reported frequent episodes of hypoglycaemia with dizziness (58%), tremors (53%), hunger (53%), sweat (37%), tingling (26%) and the most common gestures were: sugar ingestion (53%) and glycemic control (26%). Eighty-five (85%) said they used to feel hyperglycemia with fatigue (76%), polyuria (65%), polydipsia (44%) the most common precursors and the most frequent interventions were taking hypoglycemic drugs (74%) and controlling blood glucose (24%). <strong>Conclusion:</strong> The practice of self-care remains risky for diabetic patients. Hence the need for the establishment of adequate therapeutic education programs.展开更多
Extreme values of wind speed were studied based on the highly detailed ERA5 dataset covering the central part of the Kara Sea. Cases in which the ice coverage of the cells exceeded 15% were filtered. Our study shows t...Extreme values of wind speed were studied based on the highly detailed ERA5 dataset covering the central part of the Kara Sea. Cases in which the ice coverage of the cells exceeded 15% were filtered. Our study shows that the wind speed extrema obtained from station observations, as well as from modelling results in the framework of mesoscale models, can be divided into two groups according to their probability distribution laws. One group is specifically designated as black swans, with the other referred to as dragons (or dragon-kings). In this study we determined that the data of ERA5 accurately described the swans, but did not fully reproduce extrema related to the dragons;these extrema were identified only in half of ERA5 grid points. Weibull probability distribution function (PDF) parameters were identified in only a quarter of the pixels. The parameters were connected almost deterministically. This converted the Weibull function into a one-parameter dependence. It was not clear whether this uniqueness was a consequence of the features of the calculation algorithm used in ERA5, or whether it was a consequence of a relatively small area being considered, which had the same wind regime. Extremes of wind speed arise as mesoscale features and are associated with hydrodynamic features of the wind flow. If the flow was non-geostrophic and if its trajectory had a substantial curvature, then the extreme velocities were distributed according to a rule similar to the Weibull law.展开更多
文摘Objective: To analyze maternal deaths, identify causes and dysfunctions leading to these deaths in order to contribute to the implementation of strategies to reduce maternal mortality at CHU Kara. Method: Cross-sectional descriptive study involving 65 cases of maternal deaths recorded at CHU-Kara from January 1, 2018 to June 30, 2021. Results: Our study focused on 65 cases of maternal deaths recorded at the maternity ward of CHU-Kara. The average age was 30 years, with a range of 15 to 45 years. They were mostly housewives (52.3%), uneducated (38.5%), multiparous (41.5%), and referred (86.2%). The causes were mainly direct obstetric causes (81.54%), with preeclampsia and its complications (28.30%) and immediate postpartum hemorrhage (20.75%) being the most common. However, uterine rupture (20.5%) and post-abortion sepsis (16.4%) were the most lethal etiologies. Delayed evacuation (46.43%), inadequate transportation (91%), and insufficient prenatal care (72.31%) were the dysfunctions before referral. Within the CHU Kara, delays in management (58.46%), unavailability of blood and labile products (18%), and insufficient monitoring were the dysfunctions identified. Ninety-five point four percent (95.4%) of the deaths were preventable. Conclusion: The magnitude of intrahospital maternal deaths, the various dysfunctions observed in the occurrence of maternal deaths before referral/evacuation and within the hospital highlight the importance of effectively implementing recommendations from audits in the fight against maternal mortality. The majority of the deaths were preventable (95.38%).
文摘Introduction: Obstetric emergencies are common throughout the world and more particularly in developing countries where they are responsible for high maternal-fetal mortality and morbidity. Objective: Study obstetric emergencies in the maternity ward of Kara University Hospital. Method: Retrospective and descriptive study from April 1, 2022 to March 30, 2023, carried out in the Obstetrics and Gynecology Department of Kara University Hospital. Results: Eight hundred and thirty-five (835) obstetric emergencies were recorded out of 2215 admissions, i.e. a frequency of 37.7%. The average age of the patients was 26.7 with a range of 14 and 45 years. They were primigravidas (36.7%) and nulliparous (38.7%), referred (84.7%) and came from rural areas (72%). Emergencies occurred in the 3<sup>rd</sup> trimester in 74.1% and in parturients (54.1%). Preeclampsia (27%), cessation of progression of labor due to feto-pelvic disproportion (12.4%), postpartum hemorrhage (7.5%) constituted the main obstetric emergencies. In 44.8%, the delivery was carried out vaginally. Magnesium sulfate was the most used drug, i.e. 30.1%;followed by antihypertensive medications in 28.1%. Blood transfusion was performed in 24.3%. The evolution was simple in 90.9%. The maternal fatality rate was 1.6%. The perinatal case fatality rate was 12.3%. Conclusion: Obstetric emergencies are common, dominated by preeclampsia, stopping progress of labor and postpartum hemorrhages. They are responsible for high morbidity and mortality.
文摘Introduction: Endoscopic internal urethrotomy (EIU) is a method for stricture opening using transurethral incision by direct visualisation of the urethral channel, resulting in a widening of the urinary canal with the aim of improving the quality of bladder emptying. The aim of the study was to evaluate the indication and results of EIU in the treatment of stenosis of the male urethra in the Urology-Andrology Department of Kara Teaching Hospital. Methodology: This was a cross-sectional descriptive study with retrospective data collection in the Urology-Andrology department of Kara Teaching Hospital. It involved 21 records of patients with urethral stenosis treated by endoscopic internal urethrotomy (EIU) in the said department during the period from January 2021 to September 2023. The following variables were evaluated: age, circumstance of discovery, site, length, number, etiology of the urethral stenosis and evolution of the patients. Results: The mean age of the patients was 59.2 ± 11.7 years. Infectious etiology of stenosis was predominant with 10 patients (47.6%) followed by trauma with 5 cases (23.8%). The bulbar urethra was the most frequently observed site, with 11 cases (52.4%). The length was mostly less than 2 cm in 12 patients (57.1%). Stenosis was unique in 14 patients (66.7%). The mean postoperative follow-up time was 3.2 months. The result was immediately better in 11 patients (52.4%) and it was poor in 8 patients (38.1%) who required maintenance dilation sessions.
文摘Introduction: Viral hepatitis B and C constitute real public health problems worldwide. The objective of this work was to describe the epidemiological, clinical and paraclinical aspects of viral hepatitis B and c in the internal medicine department of Kara University Hospital. Method: this was a retrospective descriptive study carried out in the Internal Medicine department of Kara University Hospital, over a period of 3 years from March 2020 to April 2023. It included all patients seen in consultation or hospitalized for hepatitis viral B and/or C. Results: A total of 57 patients were included in our study. The average age was 44.30 years ± 16.75 and the M/F sex ratio was 1.38. Married people were in the majority 63.2%. The circumstances of the discovery of viral hepatitis B and C were dominated by abdominal pain in 35.1% of cases and hepatomegaly in 29.8% of cases and in 33.3% of cases, it was during screening voluntary. Patients with viral hepatitis B only accounted for 64.9% of cases;those with only viral hepatitis C represented 31.6% of cases and 3.5% of cases had HVB/HCV co-infection. We recorded 36.8% complications including 52.4% liver cirrhosis and 47.6% hepatocellular carcinomas. During the evolution, there were 03 deaths. Conclusion: the prevalence of hepatitis B and C virus carriage in patients followed in internal medicine at Kara University Hospital is high. It is therefore essential to put in place treatment and prevention strategies against these viruses.
基金This work was supported by the National Key R&D Program of China (2018YFA0606401)NSFC (U1803341)+1 种基金the 2nd Scientific Expedition to the Qinghai-Tibet Plateau (No. 2019QZKK0102)the national youth talent support program
文摘A 606 year runoff reconstruction of the Kara Darya River was developed, based on the tree-ring width chronology of Turkestan juniper(Juniperus turkestanica) from the Pamir-Alai Mountains of Kyrgyzstan. Preliminary comparison between the snow cover variation and these climate/runoff reconstructions found that Central Asian snow cover may have strong associations with large-scale ocean-atmosphere-land circulations. The runoff reconstruction demonstrated that instrumental runoff was not representative of runoff over the past 606 years. The drought of the 1960 s-1990 s resulted in low runoff levels during the past 50 years;however, this probably does not represent a worst-case scenario for the Kara Darya because the runoff reconstruction showed additional extremely low runoff prior to the 20 th century. The reconstruction will provide a long-term perspective on runoff variation in the Kara Darya River basin, aid sustainable water resource management and be useful in guiding expectations of future variations and water resource planning.
基金The authors are very grateful to the two anonymous reviewers for their comments and suggestions.The monthly reanalysis data were provided by the ECMWF(http://apps.ecmwf.int/datasets)the monthly SST and sea ice data were provided by the Hadley Centre,United Kingdom(http://www.metoffice.gov.uk/hadobs/hadisst/data/download.html)+2 种基金We thank the climate modeling groups attending CMIP5 for making their model output availableThe model data are available from the following website:http://cmip-pcmdi.llnl.gov/cmip5/data_portal.htmlThis work was supported by the Natural Science Foundation of China(Grant nos.41790475 and 41305064).
文摘This study investigated atmospheric responses in mid late winter and early spring to sea ice loss in the Barents and Kara seas using regressions of the January March mean atmosphere on Barents and Kara sea ice area in November and December.Similar atmospheric circulation responses were obtained from reanalysis data and multimodel ensemble results from the Coupled Model Intercomparison Project Phase 5,i.e.,sea ice anomalies are the dominant factor driving the overlying atmosphere.The results showed that an Arctic Asia dipole structure,with opposite anomalies over the mid-latitudes of Asia and over the adjoining Arctic,appears to be the key atmospheric circulation anomaly influencing the East Asian climate in mid late winter and early spring.
文摘In the Arctic (mainly in its European sector) there is statistically detectable seasonal reversal wind pattern. The combination of seasonally warm (cold) land surfaces in arctic areas together with cool (cool) sea surface of Arctic seas not covered by ice is conducive to the formation of a monsoon like system. On the other hand, the predominance of the cyclonic regime during all seasons makes it difficult to answer the question of whether the Arctic region belongs to the monsoon type pattern. In this study, the monsoon features of atmospheric circulation over the Barents and Kara Seas were analysed. To extract specific monsoon signs, atmospheric circulation systems (separately for areas of each sea) were divided into ten weather types. Their appearance and statistics were compared with indicators of regional circulation. A significant part of intra-annual monsoon variability is associated with the configuration of such modes as the North Atlantic Oscillation and the <em>Scandinavia</em> teleconnection patterns. For example, during the winter season, the monsoon currents (from land to sea) occur only with a positive North Atlantic Oscillation index. With the prevalence of other modes of variability, the direction of the winds can be different, and the regular monsoon circulation pattern is changed by chaotic regime. In summer, northern streams (from sea to land) are realized on the western periphery of cyclones, regenerating and stabilizing over the Kara Sea. As for anomalies, the nature of the monsoons is manifested in the statistics of extreme winds even without selecting data on the regimes of variability. So, in winter, maximum speeds fall on the southern streams, and in the summer—on the northern ones. Large precipitation anomalies during all seasons, as one would expect, are encountered most often with the cyclonic type of circulation.
基金The National Key Research and Development Program of China under contract No.2016YFC1402705the National Natural Science Foundation of China under contract No.41576189
文摘Nonlinear internal waves(NIWs) are ubiquitous around the Kara Sea, a part of the Arctic Ocean that is north of Siberia. Three hot spot sources for internal waves, one of which is the Kara Strait, have been identified based on Envisat ASAR. The generation and evolution of the NIWs through the interactions of the tide and topography across the strait is studied based on a nonhydrostatic numerical model. The model captures most wave characteristics shown by satellite data. A typical inter-packets distance on the Barents Sea side is about 25 km in summer, with a phase speed about 0.65 m/s. A northward background current may intensify the accumulation of energy during generation, but it has little influence on the other properties of the generated waves. The single internal solitary wave(ISW) structure is a special phenomenon that follows major wave trains, with a distance about 5–8 km. This wave is generated with the leading wave packets during the same tidal period. When a steady current toward the Kara Sea is included, the basic generation process is similar, but the waves toward the Kara Sea weaken and display an internal bore-like structure with smaller amplitude than in the control experiment. In winter, due to the growth of sea ice, stratification across the Kara Strait is mainly determined by the salinity, with an almost uniform temperature close to freezing. A pycnocline deepens near the middle of the water depth(Barents Sea side), and the NIWs process is not as important as the NIWs process in summer. There is no fission process during the simulation.
基金supported by the National Key Research and Development Program of China(No.2016YFC0303401)the National Natural Science Foundation of China(No.51779236)the National Natural Science Foundation of China-Shandong Joint Fund(No.U1706226).
文摘Sea ice is the predominant natural threat to marine structures and oil-gas exploitation in the Arctic.However,for ice-resistant structural design,long-term successive level ice thickness measurements are still lacking.To fill this gap in the southern Kara Sea,the Los Alamos Sea Ice Model(CICE)is applied to achieve better simulation at the local and regional scales.Based on the validation against ice thickness observations in March and April in 1980-1986,the statistical root-mean-square error is determined to be less than 0.2 m.Then,based on the hindcast data,the spatiotemporal distributions of level ice thickness are analyzed annually,seasonally,and monthly,with thicker level ice of 1.2-1.5 m in spring and large ice-free zones in September and October.For floating platforms,a novel ice grade criterion with five classifications,namely,excellent,good,moderate,severe,and catastrophic,is pro-posed.The first two grades are most suitable for offshore activities,particularly from August to October,and the moderate grade is acceptable if with ice-resistant protections.Furthermore,hostile ice conditions are discussed in terms of the generalized extreme value distribution.The statistics reveal that at a return period of 100 yr,extreme level ice is primarily between 0.6 m and 1.0 m in December.The present investigation could be a useful reference for a feasibility study of the potential risk analysis and ice-resistant operation of oil-gas exploitation in the Arctic.
基金The National Key Research and Development Program of China under contract No.2016YFC1401401the National Natural Science Foundation of China under contract Nos 41630969,41941013 and 41806225。
文摘The sea ice conditions in the Kara Sea have important impacts on Arctic shipping,oil and gas production,and marine environmental changes.In this study,sea ice coverage(C_(R))less than 30%is considered as open water,its onset and end dates are defined as T_(open)and T_(close),respectively.The sea ice melt onset(T_(melt))is defined as the date when ice-sea freshwater flux initially changes from ice into the ocean.Satellite-based sea ice concentration(SIC)from 1989 to 2019 shows a negative correlation between T_(open)and T_(close)(r=-0.77,p<0.01)in the Kara Sea.This phenomenon is also obtained through analyzing the hindcast simulation from 1994 to 2015 by a coupled ocean and sea-ice model(NAPA1/4).The model results reveal that thermodynamics dominate the sea ice variations,and ice basal melt is greater than the ice surface melt.Heat budget estimation suggests that the heat flux is significant correlated with T_(open)(r=-0.95,p<0.01)during the melt period(the duration of multi-year averaged T_(melt)to T_(open))influenced by the sea ice conditions.Additionally,this heat flux is also suggested to dominate the interannual variation of the heat input during the whole heat absorption process(r=0.81,p<0.01).The more heat input during this process leads to later T_(close)(r=0.77,p<0.01).This is the physical basis of the negative correlation between T_(open)and T_(close).Therefore,the duration of open water can be predicted by T_(open)and thence support earlier planning of marine activities.
文摘<strong>Background:</strong> Ocular coloboma is the product of an error in the fetal fissure closure, normally occurring between the fifth and sixth weeks of gestation <a href="#R1" target="_blank">[1]</a>. It may involve the cornea, iris, zonula, ciliary body, choroid, retina and optic nerve. The incidence of this syndrome is 0.7 per 10,000 live-births <a href="#R1" target="_blank">[1]</a>. The aim of this observation is to present the first case of bilateral coloboma of the iris <a href="#R1" target="_blank">[1]</a>. This case was associated with an ametropia causing a decrease in visual acuity. <strong>Case Presentation:</strong> This was a clinical observation concerning a young 12-year-old patient who consulted for blurring of vision which had progressed for approximately 2 years. The ophthalmologic examination revealed an ametropia with a bilateral notch of the pupillary rim suggesting a bilateral coloboma. There was no association with another coloboma such as chorioretinal coloboma which is quite common and is accompanied frequently by visual symptoms. <strong>Conclusion:</strong> A visual impairment of the child can indicate ametropia. However, other congenital anomalies can be discovered as was the case in this clinical observation.
文摘Background: The urology department of the Teaching Hospital of Kara is the 2nd urology department in Togo, Kara being a semi-urban town located 400 km from Lomé the capital. While for a long time only open surgery was used, the acquisition of urological endoscopic equipment in February 2021, has revolutionized the urological management of patients. Objective: Report the results of the first 15 months of urological endoscopy practice at the Kara Teaching Hospital, identify the particularities, announce the prospects. Patients and Methods. This was a retrospective and descriptive study, which took place in the urology department of the Kara Teaching Hospital, from February 2021 to April 2022, i.e. a period of 15 months. The register of operative reports and patient records were used for data collection. The following parameters were studied: age, sex, diagnosis, indication, diagnostic or therapeutic nature of the procedure, and results. EPI INFO 7.2.4.0 software was used for data analysis. Results: A total of 102 urological procedures (endoscopic and non-endoscopic) were performed during the study period;of the 102 interventions, 62 were endoscopic urological interventions, i.e., 60.7% of the interventions. The average age of patients treated was 55.5 years (±16.4) with extremes ranging from 28 to 87 years. Men accounted for 84% of patients treated. Prostatic hypertrophy was the most common urological pathology in our study, requiring endoscopic intervention in 40% of cases. Transurethral resection of the prostate was the most performed endoscopic procedure in our study with 43.5% of cases. The various endoscopic interventions resulted in success in 96.7% of cases. Conclusion: Urology nowadays cannot be done without endoscopy. At the Kara Teaching Hospital, the results are already promising after less than 24 months of endoscopic practice in urology. Advocacy must be made to political decision-makers, so that the situation is even better, for the good of both urologists and patients.
文摘Background: The urology department of the teaching hospital of Kara is the second urology department in Togo, after that of the teaching hospital Sylvanus Olympio, in Lomé the capital. It is a very young service, created less than 5 years ago. Urological emergencies were previously managed by general surgeons, for lack of urologists. The influx of patients with urological pathologies has increased with the arrival of urologists. The update on urological emergencies having been made in Lomé, we therefore wanted to take stock of urological emergencies at the teaching hospital of Kara. Objective: To describe the epidemiological, clinical, and therapeutic aspects of urological emergencies received at the teaching hospital of Kara. Patients and Methods: This was a descriptive study with retrospective data collection. The study took place in the urology department, and in the surgical emergency department of the teaching hospital of Kara, over a period of 18 months, from January 2021 to June 2022. The on-call medical team consisted of the intern in on-call medicine, and an on-call urologist, whom the intern called upon when he received a urological emergency. Pediatric urological emergencies were managed by the pediatric surgeon and were not considered in our study. The operating room register, the surgical emergency consultation register, the urology department consultation register, and the records of patients hospitalized in the urology department were used for data collection. The following parameters were studied: age, sex, type of urological emergency, and therapeutic management;epi info 7 software was used for data processing. Results: The average age of the patients was 52.5 ± 19.6 years with extremes ranging from 16 years to 102 years. Note that 57.7% of the patients were over 50 years old. The sex ratio was 8.9. Urinary retention was the most common urological emergency in 47.7% (52) of cases;follow-up of infectious pathologies in 30.2% (33) of cases. Among the patients who had been seen for urinary retention, 84.6% (44) of the cases had presented with acute urinary retention. Urethral catheterization was the type of care most received by patients, in 30.2% (33) of cases;follow-up of medical treatment in 27.5% (30) of cases. The most common etiology of urinary retention was prostate tumours, in 71.1% (37) of cases, followed by urethral stricture in 15.3% (8) of cases. We also found in our series, traumatic emergencies in 10% of cases;these were traumatic urethral injuries, traumatic injuries of external genitalia, traumatic injury of bladder, and traumatic injury of kidney in respectively: 4.5% (5);2.7% (3);1.8% (2);and 0.9% (1) of cases. Torsion of the spermatic cord was found in 2.7% (3) of cases. Conclusion: Urine retention is the most common urological emergency at Kara University Hospital. They are most often found in elderly males. Urethral catheterization was the most common type of care.
文摘Introduction: cervical cancer is common with high mortality. It is diagnosed late in developing countries. Reducing mortality requires better knowledge and screening for cervical cancer. Objective: To study the knowledge, attitudes and practices of midwives in the Kara region of cervical cancer screening. Methods: Cross-sectional, descriptive study from January 2020 to June 2020 conducted with midwives from the Kara region. Results: Fifty midwives participated in the study. The average age was 32.46 years and the majority (92%) had less than 10 years work experience. Thirty seven (74%) said that cervical cancer was due to human papillomavirus oncogenes and 32% to know the two commonly used screening methods (cervical cytology and VIA/VILI). Only 30% and 8% respectively know the pace and target of screening. They had all expressed the desire to be trained and to carry out routine screening. All of the respondents had never practiced a cervical cytology, and only 01 had once practiced VIA/VILI. Conclusion: Midwives have little knowledge of uterine cancer screening and do not practice it. They express the need to be trained in order to popularize the practice.
文摘Background: Urethral stricture is a pathology frequently encountered in urological practice. Management is often surgical, with possible recurrences. What about this pathology in Kara, a semi-urban city? Objective: Assess the management of male urethral stricture in Kara. Patients and Methods: This was a descriptive study with retrospective data collection. The study took place in the urology department of the teaching hospital of Kara, from December 2020 to December 2022. All cases of male urethral stricture, surgically treated at the teaching hospital of Kara, were listed. The inclusion criteria were as follows: any patient who had been treated surgically for male urethral stricture in the urology department of the teaching Hospital of Kara. The operating theater register and hospital records were used to collect the data. The diagnosis of urethral stricture had been made with retrograde urethrogram. A total of 24 patients were treated for male urethral stricture during the study period. The following variables were studied: age, reason for consultation, location, length, and etiology of the stricture;the type of treatment received: optical internal urethrotomy, or anastomotic urethroplasty, and the results. The result was considered good if, after removal of the urethral catheter, the patient regained his micturition without the need for dilatation;the result was considered average if, after removal of the urethral catheter, the patient needed one or more dilatation sessions to regain urination;the result was considered poor if, after removal of the catheter, the patient did not regain good micturition despite the urethral dilatation sessions. Microsoft excel and epi info 7 software were used for data processing. Results: The average age of our patients was 43.7 years ± 10.18 with extremes ranging from 27 to 70 years. The most represented age groups were that of 40 to 50 years, with 37.5% of cases;and that of 30 to 40 years with 33.3% of cases. The patients had consulted for urine retention in 66.6% of cases;the location of urethral stricture was bulbar in 45.8% of cases. The most found etiology was infectious in 58.3% of cases. Among our patients, 58.3% had received optical internal urethrotomy as treatment, while 41.6% of our patients had received anastomotic urethroplasty as treatment. Postoperatively, after removal of the urinary catheter, 87.5% of patients had benefited from one or repeated dilatation. In terms of results, we had a good result in 20.8% of patients;the result was average in 45.8% of patients, and poor in 33.3% of patients. The average duration of follow-up was 14.3 +/- 7.2 months (3-27). Conclusion: Male urethral stricture mainly affects young adults in Kara. Surgical management is done by optical internal urethrotomy and/or anastomotic urethroplasty.
文摘<strong>Objectives:</strong> To evaluate the practice of self-care in diabetic patients monitored at the Kara Teaching Hospital, known as CHU Kara. <strong>Method:</strong> We conducted a quantitative, descriptive and cross-sectional study of 40 diabetic patients monitored at the Kara CHU. The data collection took place from February 20 to May 28, 2018 and the data was collected anonymously. <strong>Results:</strong> Out of the forty (40) respondents, 60% were male with a sex ratio of 1.5 and an average age of 56.15 years. Two-thirds (2/3) of the patients did not have the blood glucose meter. More than half (52%) did not know the normal blood glucose value and 82.5% were on a low carbohydrate diet. Eighty-two point fifty percent (82.50%) were under Oral antidiabetic (ADO). Forty percent (40%) of patients often forgot their medication. Forty-seven point-fifty percent reported frequent episodes of hypoglycaemia with dizziness (58%), tremors (53%), hunger (53%), sweat (37%), tingling (26%) and the most common gestures were: sugar ingestion (53%) and glycemic control (26%). Eighty-five (85%) said they used to feel hyperglycemia with fatigue (76%), polyuria (65%), polydipsia (44%) the most common precursors and the most frequent interventions were taking hypoglycemic drugs (74%) and controlling blood glucose (24%). <strong>Conclusion:</strong> The practice of self-care remains risky for diabetic patients. Hence the need for the establishment of adequate therapeutic education programs.
文摘Extreme values of wind speed were studied based on the highly detailed ERA5 dataset covering the central part of the Kara Sea. Cases in which the ice coverage of the cells exceeded 15% were filtered. Our study shows that the wind speed extrema obtained from station observations, as well as from modelling results in the framework of mesoscale models, can be divided into two groups according to their probability distribution laws. One group is specifically designated as black swans, with the other referred to as dragons (or dragon-kings). In this study we determined that the data of ERA5 accurately described the swans, but did not fully reproduce extrema related to the dragons;these extrema were identified only in half of ERA5 grid points. Weibull probability distribution function (PDF) parameters were identified in only a quarter of the pixels. The parameters were connected almost deterministically. This converted the Weibull function into a one-parameter dependence. It was not clear whether this uniqueness was a consequence of the features of the calculation algorithm used in ERA5, or whether it was a consequence of a relatively small area being considered, which had the same wind regime. Extremes of wind speed arise as mesoscale features and are associated with hydrodynamic features of the wind flow. If the flow was non-geostrophic and if its trajectory had a substantial curvature, then the extreme velocities were distributed according to a rule similar to the Weibull law.