A Comparison between Late Preterm and Term Infants with Respiratory Distress Syndrome, Early-Onset Sepsis, and Neonatal Jaundice in Ecuadorian Newborns

Background: To examine the differences in prevalence of respiratory distress syndrome, early-onset sepsis and jaundice, between late preterm infants versus term infants in Ecuadorian newborns. Methods: Study design: Epidemiological, observational, and cross-sectional, with two cohorts of patients. Settings: IESS Quito Sur Hospital at Quito, Ecuador, from February to April of 2020. Participants: This study included 204 newborns, 102 preterm infants, 102 term infants. Results: There are significant differences between late preterm infants and term infants, with a p-value of 0.000 in the prevalence of early sepsis, 70.59% vs. 35.29%. In respiratory distress syndrome between late and term premature infants, significant differences were observed with a p-value of 0.000, the proportion being 55.58% vs. 24.51% respectively. The prevalence of jaundice is higher in term infants with a p value of 0.002, 72.55%, versus 51.96% in late preterm infants, and the mean value of bilirubins in mg/dL was higher in term infants 14.32 versus 12.33 in late preterm infants;this difference is statistically significant with a p value of 0.004. Admission to the NICU is more frequent in late preterm infants with a p-value of 0.000, being 42.16% for late preterm infants vs. 7.84% in term infants;the mean of the hospital days with p-value 0.005, was higher in late preterm infants 4.97 days vs. 3.55 days for term newborns. Conclusion: Due to the conditions of their immaturity, late preterm infants are 2.86 times more likely to present early sepsis than full-term newborns. It is shown that late preterm infants are 2.69 times more likely to have respiratory distress syndrome compared to term infants, therefore, late preterm infants have a longer hospital stay of 4.97 days versus 3.55 days in term infants. Jaundice and mean bilirubin levels are higher in term infants due to blood group incompatibility and insufficient breastfeeding.

Clinical characteristics of patients with early-and late-onset optic neuromyelitis optica spectrum disease

Objective:To analyze the different clinical features of patients with early-onset(EO-NMOSDs)and late-onset neuromyelitis optica spectrum diseases(LO-NMOSDs).Methods:A total of 51patients with neuromyelitis optica spectrum disease who were diagnosed in our hospital for the first time from January 2015 to December 2022 were included in the First Affiliated Hospital of Hainan Medical College and divided into 22 cases in the EO-NMOSDs group and 29 cases in the LO-NMOSDs group according to whether the age of onset was 50 years old.The basic data,Extended Disability Status Scale(EDSS)score,blood and cerebrospinal fluid test indicators of the two groups were statistically analyzed.Results:There were no significant differences in demographic characteristics,clinical features and serum AQP-4 antibody positivity rate between the two groups(all P>0.05),and there were significant differences in triglycerides(TG),low-density lipoprotein(LDL),apolipoprotein A(APOA),apolipoprotein B(APOB)and lipoprotein a(P=0.010,P=0.048,P=0.014,P=0.061,P=0.001,respectively),and cerebrospinal fluid LDH,There were significant differences between microprotein quantification and EDSS score(P=0.018,P=0.034,P=0.025,respectively),and the level of microprotein quantification in cerebrospinal fluid of LO-NMOSDs had a certain correlation with the degree of disability(r=0.52,P<0.03).Conclusion:LO-NMOSDs and EO-NMOSDs group patients have similar demographic characteristics,serum AQP-4 antibody positive rate and clinical features,but compared with EO-NMOSDs,patients in LO-NMOSDs group are prone to abnormal lipid metabolism,higher trace proteins in cerebrospinal fluid and more likely to be disabled,and among LO-NMOSDs,the higher the trace protein in the cerebrospinal fluid,the more severe the disability status of patients.

Climate prediction of the seasonal sea-ice early melt onset in the Bering Sea

基于大尺度环流异常对海冰消融的影响过程,本文采用年际增量预测方法研制了白令海季节性海冰早期消融开始日期(EMO)的统计预测模型.预测模型选取了3个具有明确物理意义的预测因子:1月波弗特高压,前期11月东西伯利亚地区海平面气压,以及11月东欧平原积雪覆盖率。1月波弗特高压可以通过海气相互作用影响白令海地区海温异常,该海温异常能够从1月持续到3月,进而影响白令海EMO.11月东西伯利亚地区海平面气压与11月至次年2月北太平洋中纬度东部海温密切相关。伴随着北太平洋中纬度东部冷海温异常的出现,白令海地区会出现暖海温异常,进而导致白令海海冰范围减少,EMO较晚.1月北极偶极子异常是11月东欧平原积雪覆盖率影响次年白令海EMO的桥梁之一.1981-2022年的交叉检验结果表明:统计模型对白令海EMO具有较好的预测能力,预测与观测的EMO之间时间相关系数达到了0.45,超过了99%的置信水平.统计模型对白令海EMO正常年份和异常年份的预测准确率分别为60%和41%.

Approach to early-onset colorectal cancer:Clinicopathological,familial,molecular and immunohistochemical characteristics

AIM:To characterize clinicopathological and familial features of early-onset colorectal cancer(CRC) and compare features of tumors with and without microsatellite instability(MSI).METHODS:Forty-five patients with CRC aged 45 or younger were included in the study.Clinical information,a three-generation family history,and tumor samples were obtained.MSI status was analyzed and mismatch repair genes were examined in the MSI families.Tumors were included in a tissue microarray and an immunohistochemical study was carried out with a panel of selected antibodies.RESULTS:Early onset CRC is characterized by advanced stage at diagnosis,right colon location,low-grade of differentiation,mucin production,and presence of polyps.Hereditary forms represent at least 21% of cases.Eighty-one percent of patients who died during followup showed a lack of expression of cyclin E,which could be a marker of poor prognosis.β-catenin expression was normal in a high percentage of tumors.CONCLUSION:Early-onset CRC has an important familial component,with a high proportion of tumors showing microsatellite stable.Cyclin E might be a poor prognosis factor.

Circulating MicroRNAs as Novel Diagnostic Biomarkers for Very Early-onset(≤40 years) Coronary Artery Disease

Objective Very early-onset coronary artery disease （CAD） is a great challenge in cardiovascular medicine throughout the world, especially regarding its early diagnosis. This study explored whether circulating microRNAs （miRNAs） could be used as potential biomarkers for patients with very early-onset CAD. Methods We performed an initial screening of miRNA expression using RNA isolated from 20 patients with angiographically documented very early-onset CAD and 20 age- and sex-matched normal controls. For further confirmation, we prospectively examined the miRNAs selected from 40 patients with very early-onset CAD and 40 angiography-normal controls. Results A total of 22 overexpressed miRNAs and 22 underexpressed miRNAs were detected in the initial screening. RT-qPCR analysis of the miRNAs obtained from the initial screening revealed that four miRNAs including miR-196-5p, miR-3163-3p, miR-145-3p, and miR-190a-5p exhibited significantly decreased expression in patients compared with that in controls （P〈0.05）. The areas under the receiver operating characteristic curve for these miRNAs were 0.824 （95% CI, 0.731-0.917; P〈0.001）, 0.758 （95% CI, 0.651-0.864; P〈0.001）, 0.753 （95% CI, 0.643-0.863; P〈0.001）, and 0.782 （95% CI, 0.680-0.884; P〈0.001）, respectively, in the validation set. Conclusion To our knowledge, this is an advanced study to report about four serum miRNAs （miR-196-5p, miR-3163-3p, miR-145-3p, and miR-190a-5p） that could be used as novel biomarkers for the diagnosis of very early-onset CAD.

Molecular approach to genetic and epigenetic pathogenesis of early-onset colorectal cancer

Colorectal cancer(CRC) is the third most frequent cancer type and the incidence of this disease is increasing gradually per year in individuals younger than 50 years old. The current knowledge is that early-onset CRC(EOCRC) cases are heterogeneous population that includes both hereditary and sporadic forms of the CRC. Although EOCRC cases have some distinguishing clinical and pathological features than elder age CRC, the molecular mechanism underlying the EOCRC is poorly clarified. Given the significance of CRC in the world of medicine, the present review will focus on the recent knowledge in the molecular basis of genetic and epigenetic mechanism of the hereditary forms of EOCRC, which includes Lynch syndrome, Familial CRC type X, Familial adenomatous polyposis, Mut YH-associated polyposis, Juvenile polyposis syndrome, Peutz-Jeghers Syndrome and sporadic forms of EOCRC. Recent findings about molecular genetics and epigenetic basis of EOCRC gave rise to new alternative therapy protocols. Although exact diagnosis of these cases still remains complicated, the present review paves way for better predictions and contributes to more accurate diagnostic and therapeutic strategies into clinical approach.

Early-onset colorectal cancer:A sporadic or inherited disease?

Colorectal cancer is the third most common cancer diagnosed worldwide.Although epidemiology data show a marked variability around the world,its overall incidence rate shows a slow but steady decrease,mainly in developed countries.Conversely,early-onset colorectal cancer appears to display an opposite trend with an overall prevalence in United States and European Union ranging from 3.0% and 8.6%.Colorectal cancer has a substantial proportion of familial cases.In particular,early age at onset is especially suggestive of hereditary predisposition.The clinicopathological and molecular features of colorectal cancer cases show a marked heterogeneity not only between early- and late-onset cases but also within the early-onset group.Two distinct subtypes of early-onset colorectal cancers can be identified:a "sporadic" subtype,usually without family history,and an inherited subtype arising in the context of well defined hereditary syndromes.The pathogenesis of the early-onset disease is substantially well characterized in the inherited subtype,which is mainly associated to the Lynch syndrome and occasionally to other rare mendelian diseases,whereas in the "sporadic" subtype the origin of the disease may be attributed to the presence of various common/rare genetic variants,so far largely unidentified,displaying variable penetrance.These variants are thought to act cumulatively to increase the risk of colorectal cancer,and presumably to also anticipate its onset.Efforts are ongoing in the attempt to unravel the intricate genetic basis of this "sporadic" early-onset disease.A better knowledge of molecular entities and pathways may impact on family-tailored prevention and clinical management strategies.

Early-onset gastric cancer:Learning lessons from the young

There is by no means a clear-cut pattern of mutations contributing to gastric cancers,and gastric cancer research can be hampered by the diversity of factors that can induce gastric cancer,such as Helicobacter pylori infection,diet,ageing and other environmental factors.Tumours are unquestionably riddled with genetic changes yet we are faced with an unsolvable puzzle with respect to a temporal relationship.It is postulated that inherited genetic factors may be more important in early-onset gastric cancer (EOGC) than in gastric cancers found in older patients as they have less exposure to environmental carcinogens.EOGC,therefore,could provide a key to unravelling the genetic changes in gastric carcinogenesis.Gastric cancers occurring in young patients provide an ideal background on which to try and uncover the initiating stages of gastric carcinogenesis.This review summarizes the literature regarding EOGC and also presents evidence that these cancers have a unique molecular-genetic phenotype,distinct from conventional gastric cancer.

Early-onset colorectal cancer:A separate subset of colorectal cancer

Colorectal cancer(CRC)has a great impact on the world population.With increasing frequency,CRC is described according to the presenting phenotype,based on its molecular characteristics.Classification of CRC tumors according to their genetic and/or epigenetic alterations is not only important for establishing the molecular bases of the disease,but also for predicting patient outcomes and developing more individualized treatments.Early-onset CRC is a heterogeneous disease,with a strong familial component,although the disease is sporadic in an important proportion of cases.Different molecular alterations appear to contribute to the apparent heterogeneity of the early-onset population and subgroups can be distinguished with distinct histopathologic and familial characteristics.Moreover,compared with late-onset CRC,there are characteristicsthat suggest that early-onset CRC may have a different molecular basis.The purpose of this review was to analyze the current state of knowledge about earlyonset CRC with respect to clinicopathologic,familial and molecular features.Together,these features make it increasingly clear that this subset of CRC may be a separate disease,although it has much in common with late-onset CRC.

Role of DYT1 gene in early-onset primary torsion dystonia

Mutation of the DYT1 gene has been reported to cause early-onset primary torsion dystonia （DYT1） Due to DYT1 gene mutation, defective wild torsinA and the accumulation of mutant torsinA （GAG-deleted DYT1 gene encoded the mutant torsinA, torsinA＆E） play an important role in DYT1 pathogenesis. Intracellular inclusion bodies are formed, and dopamine transport and release are disturbed by interfering functions of endoplasmic reticulum, nuclear membrane, and cytoskeleton of neural cells, resulting in DYT1 onset. Small interfering RNA could serve as a potential therapy for DYT1. However, the exact function of wild torsinA and the pathological effects of torsinAAE require further studies.

Different Fetal and Neonatal Growth between Early- and Late-Onset Preeclampsia

Preeclampsia is a heterogeneous disease, and there are major differences in severity, fetal growth and poor placentation between early- and late-onset preeclampsia. Here, we examined the effect of onset period on fetal and neonatal growth in preeclampsia with a cross-sectional study including 102 pregnant women with preeclampsia visited Okayama University Hospital from 2009 to 2013. The subjects were retrospectively compared in terms of body mass index (BMI), weight gain during pregnancy, complications, weeks of delivery, neonatal body weight and BMI at birth, fetal growth restriction (FGR), small for gestational age (SGA), pathological findings in the placenta, and infant’s weight at 1 month after birth. Neonatal body weight and BMI at birth were significantly lower and the extent of FGR and the frequency of SGA were higher in early-onset group compared with late-onset group. Mean daily weight gain during the neonatal period was significantly lower in the early-onset group compared with the late-onset group, however the weight gain rate during the neonatal period in the early-onset group was higher than that in late-onset group. In conclusions, there are significant differences in fetal and neonatal growth between early- and late-onset preeclampsia and the catch up for growth might start during neonatal period.

Serial elongation-derotation-flexion casting for children with early-onset scoliosis

Various early-onset spinal deformities, particularly infantile and juvenile scoliosis(JS), still pose challenges to pediatric orthopedic surgeons. The ideal treatment of these deformities has yet to emerge, as both clinicians and surgeons still face multiple challenges including preservation of thoracic motion, spine and cage, and protection of cardiac and lung growth and function. Elongation-derotation-flexion(EDF) casting is a technique that uses a custom-made thoracolumbar cast based on a three-dimensional correction concept. EDF can control progression of the deformity and- in some cases-coax the initially-curved spine to grow straighter by acting simultaneously in the frontal, sagittal and coronal planes. Here we provide a comprehensive review of how infantile and JS can affect normal spine and thorax and how serial EDF casting can be used to manage these spinal deformities. A fresh review of the literature helps fully understand the principles of the serial EDF casting technique and the effectiveness of conservative treatment in patients with early-onset spinal deformities, particularly infantile and juvenile scolisois.

Detection of Alzheimer’s disease onset using MRI and PET neuroimaging:longitudinal data analysis and machine learning

The scientists are dedicated to studying the detection of Alzheimer’s disease onset to find a cure, or at the very least, medication that can slow the progression of the disease. This article explores the effectiveness of longitudinal data analysis, artificial intelligence, and machine learning approaches based on magnetic resonance imaging and positron emission tomography neuroimaging modalities for progression estimation and the detection of Alzheimer’s disease onset. The significance of feature extraction in highly complex neuroimaging data, identification of vulnerable brain regions, and the determination of the threshold values for plaques, tangles, and neurodegeneration of these regions will extensively be evaluated. Developing automated methods to improve the aforementioned research areas would enable specialists to determine the progression of the disease and find the link between the biomarkers and more accurate detection of Alzheimer’s disease onset.

Molecular alterations in gastric cancer with special reference to the early-onset subtype

Currently, gastric cancer(GC) is one of the most frequently diagnosed neoplasms, with a global burden of 723000 deaths in 2012. It is the third leading cause of cancer-related death worldwide. There are numerous possible factors that stimulate the procarcinogenic activity of important genes. These factors include genetic susceptibility expressed in a singlenucleotide polymorphism, various acquired mutations(chromosomal instability, microsatellite instability, somatic gene mutations, epigenetic alterations) and environmental circumstances(e.g., helicobcter pylori infection, EBV infection, diet, and smoking). Most of the aforementioned pathways overlap, and authors agree that a clear-cut pathway for GC may not exist. Thus, the categorization of carcinogenic events is complicated. Lately, it has been claimed that research on early-onset gastric carcinoma(EOGC) and hereditary GC may contribute towards unravelling some part of the mystery of the GC molecular pattern because young patients are less exposed to environmental carcinogens and because carcinogenesis in this setting may be more dependent on genetic factors. The comparison of various aspects that differ and coexist in EOGCs and conventional GCs might enable scientists to: distinguish which features in the pathway of gastric carcinogenesisare modifiable, discover specific GC markers and identify a specific target. This review provides a summary of the data published thus far concerning the molecular characteristics of GC and highlights the outstanding features of EOGC.

Molecular Analyses of Early-Onset Gastric Cancer in Brazilian Patients: <i>TP</i>53 Mutations, Cadherin-Catenin and Mucins Proteins Expression

Early gastric carcinomas may develop with a molecular profile differing from sporadic carcinomas occurring at a later age. In this study, we analyzed a retrospective series of 88 patients with gastric adenocarcinoma diagnosed before the age of 45 years for the presence of TP53 mutations, clinicopathological features and immunohistochemistry to evaluate the expression of markers considered to be important in gastric carcinogenesis (E-cadherin, β-catenin, MUC1, MUC2, MUC5AC, MUC6 and p53). The majority of proportion of tumors were diffuse-type (70%) and advanced stage (56%). Familial history of cancer was positive in 21% of the cases. There was a significant association between altered expression of E-cadherin and β-catenin, and between p53 expression and perineural invasion. TP53 mutations were detected in 14.5% of evaluated cases, including a germline mutation (p.R337H) in a 12-year old patient. Overall survival analysis showed significant differences in relation with tumor stage and histopathology. The evaluated biomarkers did not present prognostic value in non-exploratory multivariate analyses. The low frequency of TP53 mutations in this series suggests these alterations are not a major molecular event in gastric cancer occurring at early age, although the identification of a case with germline p.R337H mutation is consistent with the hypothesis that a small proportion of early, apparently sporadic gastric cancer, may be associated with widespread Brazilian founder mutations. Further studies are needed to evaluate the prognostic significance of markers for specific groups of patients according to tumor histology and familial history.

Early-Onset Alzheimer’s Disease and Metabolic Dysfunction, a Comparative Review

Alzheimer’s disease is quickly becoming one of the most known diseases in the country due to its devastating effects and lack of treatment options. Within this lethal disease, there is a smaller group, those individuals that are diagnosed with early-onset Alzheimer’s disease. It is understood that these individuals see faster effects of the disease and die considerably sooner, but it is not understood why. This review compares the early-onset (EOAD) and late-onset (LOAD) types to try and determine some of the most blaring differences between the two. The genetic basis linking EOAD and LOAD has been the apolipoprotein E gene (APOE) to indicate metabolic alteration with the &#949;4 allele specifically. The topographical atrophy disparities between EOAD and LOAD supported the more noticeable cognitive differences between the two Alzheimer’s disease categories. The faster and wider spread atrophy of EOAD patients correlates with the difficulty they experience with attention, language, visuo-spatial, and executive functions. Finally, brain metabolism differs between both AD subtypes as well, where EOAD indicates the wide spread damage and metabolic breakdown across more diverse regions of the brain.

Mutation analysis of ATP13A2 in early-onset parkinsonism patients

BACKGROUND： A recent study has found that ATP13A2 is the causative gene for PARK9-linked autosomal recessive early-onset parkinsonism, described previously in Jordanian and Chilean families （Kufor-Rakeb syndrome）. OBJECTIVE： To screen eastern Asian patients with early-onset parkinsonism for mutations in ATP13A2 and to describe positron emission tomography （PET） findings of PARK9-linked parkinsonism. DESIGN, TIME AND SETTING： In total, 117 patients were selected from the Department of Neurology, Juntendo University, from February 2003 to October 2006, for this molecular genetics and case-control study. PARTICIPANTS： The patients with parkinsonism consist of two cohorts. Ninety four patients with onset age of less than 30 years were selected for the first cohort. They included 49 males and 44 females, comprising 73 Japanese, 9 Korean, 8 Taiwan Residents, and 4 Mainland Chinese. Eleven patients had parkinsonism complicated with dementia, 15 patients had family histories of parkinsonism （including 2 families）, and 5 patients were from consanguineous parents （including one family）. The second cohort of 23 patients was composed of patients with consanguineous parents （n = 15） or who had affected siblings （n = 6） or both （n = 2）, but the age at onset ranged from 30 to 50 years. METHODS： In 117 patients with parkinsonism, direct sequencing of ATP13A2 exons 13, 16, and 26, in which mutations had been reported previously, were performed. Sequencing was also performed in all 29 exons, including splice sites, in 28 probands who showed homozygosity at the PARK9 locus by haplotype analysis. Mutation analysis was also performed in 150 normal people. Linkage analysis was performed on all 3 parkinsonism families using short tandem repeat markers flanking the PARK9 locus. For patients who had ATP13A2 mutation, we performed brain MRI and ^18F-dopa PET scans. MAIN OUTCOME MEASURES： ATP13A2 DNA sequence, ^18F-dopa PET scan and brain MRI findings. RESULTS： A novel F182L mutation in a consanguineous Japanese family was identified. The patient was homozygous for the F182L mutation and her unaffected parents and two unaffected siblings were heterozygous for the F182L mutation. The patient developed early-onset atypical parkinsonism, which resembled the originally reported Kufor-Rakeb syndrome. MRI examination showed spinal cord atrophy and ^18F-dopa PET scan findings were similar to those of Parkinson＇s disease. CONCLUSION： Detection of the new PARK9 mutation, together with the previously reported cases of PARK9-linked parkinsonism, expand the clinical phenotypic spectrum of levodopa-responsive parkinsonism.

Elderly patients with very late-onset schizophrenia-like psychosis and early-onset schizophrenia: Cross-sectional and retrospective clinical findings

Objectives: The aim of this study was to characterize the symptoms at onset/past and current symptoms of patients with Very Late-Onset Schizophrenia-Like Psychosis (VLOSLP;first onset of psychotic symptoms at/or after 60 years old) with those of elderly patients diagnosed with schizophrenia before the age of 40 years old (Early-Onset Schizophrenia—EOS) in order to validate the clinical nosology proposed by the International Late-Onset Schizophrenia Group. Methods: This is a between-patient comparison study with retrospective and current data taken from an historical cohort that was conducted from May/2005 to August/2008. Seventeen VLOSLP and 17 EOS were included. Schizophrenia and schizophrenia-like psychotic disorders were initially diagnosed by board-certified psychiatrists with the Diagnostic and Statistical Manual Criteria at use at onset of the disorders. Patients’ symptoms were assessed with the Scale for the Assessment of Positive Symptoms (SAPS) and the Scale for the Assessment of Negative Symptoms (SANS). The general scores on the SAPS/SANS were the primary outcomes. Results: Both groups had hallucinations and delusions at onset of the disease, but the following symptoms were more present and severe in EOS than in VLOSLP: hallucinations (p = 0.001);assiduity loss (p p = 0.001), reference (p p = 0.001) delusions. VLOSLP had mostly persecutory delusions. At current evaluation (follow-up of cohort), most patients in the two groups presented residual symptoms of anhedonia and apathy, but EOS, presented more symptoms of friendship poverty (d = 1.42, large effect size) than VLOSLP. The neuroimaging studies (when available) at follow-up demonstrated greater vascular cerebral lesions/vulnerability in VLOSLP than in EOS patients. Conclusion: This study showed that both VLOSLP and EOS had positive and negative symptoms in the past/at onset of the disease, but they were more severe in EOS than in VLOSLP. However, the positive symptoms of both groups at follow-up of the cohort (current evaluation) responded relatively well to neuroleptics.

Influences of MJO-induced Tropical Cyclones on the Circulation-Convection Inconsistency for the 2021 South China Sea Summer Monsoon Onset

The South China Sea Summer Monsoon(SCSSM)onset is characterized by an apparent seasonal conversion of circulation and convection.Accordingly,various indices have been introduced to identify the SCSSM onset date.However,the onset dates as determined by various indices can be very inconsistent.It not only limits the determination of onset dates but also misleads the assessment of prediction skills.In 2021,the onset time as identified by the circulation criteria was 20 May,which is 12 days earlier than that deduced by also considering the convection criteria.The present study mainly ascribes such circulation-convection inconsistency to the activities of tropical cyclones(TCs)modulated by the Madden-Julian Oscillation(MJO).The convection of TC“Yaas”(2021)acted as an upper-level diabatic heat source to the north of the SCS,facilitating the circulation transition.Afterward,TC“Choi-wan”(2021)over the western Pacific aided the westerlies to persist at lower levels while simultaneously suppressing moist convection over the SCS.Accurate predictions using the ECMWF S2S forecast system were obtained only after the MJO formation.The skillful prediction of the MJO during late spring may provide an opportunity to accurately predict the establishment of the SCSSM several weeks in advance.

The Inter-Annual Variability of Rainfall Onset and Its Implication on Crop Planting in Selected East Africa Countries

The inter-annual variability of rainfall onset and crop replanting in East Africa (EA) was assessed using daily estimated rainfall data from climate hazard group infrared precipitation (CHIRPS Ver2.0) and monthly Sea Surface Temperature (SST) indices [Indian Ocean Dipole (IOD) and El-Ni?o Southern Oscillation (ENSO) at NINO3.4 region] from the National Center for Environmental Prediction (NCEP) and the National Center for Atmospheric Research (NCAR). The data covered a period of 40 years from1981 to 2020. The methods of cumulative of daily mean rainfall, percentage of onset date departure (PODD), Mann-Kendall (MK) trend test, student t-test, and correlation were applied in the analysis. The results showed that early onset with dry spell (WDS) consideration frequently occurs in Uganda between the first and second dekads of September, while late rainfall onset WDS occurs in the first and second dekads of December over central and Northern Kenya as well as in the Northeastern highlands, parts of the northern coast and unimodal regions in Tanzania. Rainfall onset with no dry spell (WnDS) portrayed an average of 10 days before the occurrence of true onset WDS, with maximum onset departure days (ODD) above 30 days across the Rift Valley area in Kenya and the Northeastern highlands in Tanzania. The high chance of minimum ODD is seen over entire Uganda and the area around Lake Victoria. However, few regions, such as Nakuru (Kenya) Gulu and Kibale (Uganda), and Gitega (Burundi), revealed a slight positive linear trend while others showed negative trend. Significant positive patterns for correlation between onset WDS and SST indices (IOD and NINO 3.4) were discovered in Northern and Northeastern Kenya, as well as areas along the Indian Ocean (over Tanzania’s Northern Coast). Inter-annual relationship between onset dates WDS and IOD (NINO3.4) indices exhibits a high correlation coefficient r = 0.23 (r = 0.48) in Uganda and r = 0.44 (r = 0.36) in Kenya. On the other hand, a negative correlation was revealed over Burundi and Tanzania (over a unimodal region). A high percentage of PODD was observed, ranging from 40% to 70% over the Rift Valley in Kenya and at the Northeastern highlands in Tanzania. However, a strong PODD above 70% was observed over Tanga and the Northern Pwani Region in Tanzania. These findings will help farmers to understand the appropriate time for crop planting, as well as help other socio-economic activities that strongly depend on rainfall.