Age, maturation, and population structure of the Humboldt squid Dosidicus gigas off the Peruvian Exclusive Economic Zones

Age, maturation and population structure of the Humboldt squid Dosidicus gigas were studied based on random sampling of the Chinese jigging fishery off the Peruvian Exclusive Economic Zones （EEZ） during 2008-2010. Estimated ages ranged from 144 to 633 days, confirming that the squid is a short-lived species with longevity no longer than 2 years. Occurrence of mature females and hatching in each month indicated that Humboldt squid spawned year-round. Back-calculated hatching dates for the samples were from January 22^nd, 2008 to April 22nd, 2010 with a peak between January and March. Two size-based and two hatching date-based populations could be defined from mantle length （ML） at maturity and back-calculated hatching dates, respectively. Females matured at a larger size than males, and there was a significant difference in ML at maturity between the two hatching groups （P〈0.05）. The waters adjacent to 1 l^S off the Peruvian EEZ may be a potential spawning ground. This study shows the complexity of the population structure and large variability in key life history parameters in the Humboldt squid off the Peruvian EEZ, which should be considered in the assessment and management of this important resource.

Spatial distribution pattern of Picea schrenkiana population in the Middle Tianshan Mountains and the relationship with topographic attributes

The spatial distribution of plant populations is an important feature of population structure and it de- termines the population＇s ecological preferences, biological characteristics and relationships with environmental factors. The point pattern analysis method was adopted to study the distribution pattern of Picea schrenkiana indi- viduals of different size classes and the correlations between two size classes as well as the impact of topog- raphical attributes on the population distribution. With increasing diameter at breast height, the plant density of the P. schrenkiana population showed a declining trend. Old trees showed a random distribution at a small spatial scale （0-12 m）, whereas saplings, small trees and big trees all had an aggregated distribution at all scales. With the increase of tree age, the scales at which maximal aggregation occurred gradually increased and the aggregation strength decreased. At a small scale （0-16 m）, all size classes showed a negative correlation and the larger the difference between tree size, the more significant the negative correlation. The number of medium, big and old trees had a significantly positive correlation with elevations, whereas the number of saplings and small trees was not significantly correlated with elevations. The numbers of saplings, small and medium trees showed a significant positive correlation with slope gradient, whereas the number of big trees was not significantly correlated, and the number of old trees was negatively correlated with gradient. With the exception of old trees, saplings, small, me- dium and big trees showed negative correlations with convexity index. The study provides a theoretical basis for the conservation, rehabilitation and sustainable management of forest ecosystems in the Tianshan Mountains.

Skeletochronological Study of Age,Longevity and Growth in a Population of Rana nigromaculata(Amphibia:Anura) in Sichuan,China

A skeletochronological study was conducted for the age, longevity and growth of a Rana nigromaculata population in northeastern Sichuan, China. Of 139 specimens, 119(68 males and 51 females) exhibited distinct arrested growth lines in phalanges. Age at first reproduction was found to be two years of age for males and three for females. Maximum longevity was estimated to be at least six years in males and seven years in females. Average age did not differ between males and females. Breeding females were significantly older than breeding males. Females were larger in body size and heavier in body mass than males. Age was not correlated with body size and body mass in males, but a significant correlation was found among age, body size and body mass in females. The growth curve appeared significantly different between the sexes, with a higher growth rate throughout life and a larger asymptotic size in females. Moreover, analysis of the growth model indicated that the population studied was relatively stable.

Subtotal colonic bypass plus colostomy with antiperistaltic cecoproctostomy for the treatment of slow transit constipation in an aged population:A retrospective control study

AIM To compare the efficacy,improved quality of life,and prognosis in patients undergoing either subtotal colonic bypass with antiperistaltic cecoproctostomy(SCBAC) or subtotal colonic bypass plus colostomy with antiperistaltic cecoproctostomy(SCBCAC) for the treatment of slow transit constipation.METHODS Between October 2010 and October 2014,aged patients with slow transit constipation who were hospitalized and underwent laparoscopic surgery in our institute weredivided into two groups: the bypass group,15 patients underwent SCBAC,and the bypass plus colostomy group,14 patients underwent SCBCAC. The following preoperative and postoperative clinical data were collected: gender,age,body mass index,operative time,first flatus time,length of hospital stay,bowel movements(BMs),Wexner fecal incontinence scale,Wexner constipation scale(WCS),gastrointestinal quality of life index(GIQLI),numerical rating scale for pain intensity(NRS),abdominal bloating score(ABS),and ClavienDindo classification of surgical complications(CD) before surgery and at 3,6,12,and 24 mo after surgery.RESULTS All patients successfully underwent laparoscopic surgery without open surgery conversion or surgeryrelated death. The operative time and blood loss were significantly less in the bypass group than in the bypass plus colostomy group(P = 0.007). No significant differences were observed in first flatus time,length of hospital stay,or complications with CD > 1 between the two groups. No patients had fecal incontinence after surgery. At 3,6,and 12 mo after surgery,the number of BMs was significantly less in the bypass plus colostomy group than in the bypass group. The parameters at 3,6,12,and 24 mo after surgery in both groups significantly improved compared with the preoperative conditions(P < 0.05),except NRS at 3,6 mo after surgery in both groups,ABS at 12,24 mo after surgery and NRS at 12,24 mo after surgery in the bypass group. WCS,GIQLI,NRS,and ABS significantly improved in the bypass plus colostomy group compared with the bypass group at 3,6,12,and 24 mo after surgery(P < 0.05) except WCS,NRS at 3,6 mo after surgery and ABS at 3 mo after surgery. At 1 year after surgery,a barium enema examination showed that the emptying time was significantly better in the bypass plus colostomy group than in the bypass group(P = 0.007).CONCLUSION Laparoscopic SCBCAC is an effective and safe procedure for the treatment of slow transit constipation in an aged population and can significantly improve the prognosis. Its clinical efficacy is more favorable compared with that of SCBAC. Laparoscopic SCBCAC is a better procedure for the treatment of slow transit constipation in an aged population.

Closed-loop control of epileptiform activities in a neural population model using a proportional-derivative controller

Epilepsy is believed to be caused by a lack of balance between excitation and inhibitation in the brain. A promising strategy for the control of the disease is closed-loop brain stimulation. How to determine the stimulation control parameters for effective and safe treatment protocols remains, however, an unsolved question. To constrain the complex dynamics of the biological brain, we use a neural population model（NPM）. We propose that a proportional-derivative（PD） type closed-loop control can successfully suppress epileptiform activities. First, we determine the stability of root loci, which reveals that the dynamical mechanism underlying epilepsy in the NPM is the loss of homeostatic control caused by the lack of balance between excitation and inhibition. Then, we design a PD type closed-loop controller to stabilize the unstable NPM such that the homeostatic equilibriums are maintained; we show that epileptiform activities are successfully suppressed. A graphical approach is employed to determine the stabilizing region of the PD controller in the parameter space, providing a theoretical guideline for the selection of the PD control parameters. Furthermore, we establish the relationship between the control parameters and the model parameters in the form of stabilizing regions to help understand the mechanism of suppressing epileptiform activities in the NPM. Simulations show that the PD-type closed-loop control strategy can effectively suppress epileptiform activities in the NPM.

Structure of Isolated <i>Acer grandidentatum</i>(Bigtooth Maple) Communities and Potential Population Changes

Isolated, relic populations of Acer grandidentatum (bigtooth maple, Sapindaceae) were found in deep canyons in central Texas. Associated with them on hilltops were communities of Juniperus ashei (ash juniper). We determined the structure of relic A. grandidentatum populations and compared them to adjacent J. ashei populations. The overstory and understory density was counted and basal area was determined for all woody species in both communities using the quadrat procedure. Acer grandidentatum was the highest density (788 ± 964 or 52%) and basal area (29 ± 35 or 52%) overstory species in the canyon communities while J. ashei had the highest density (1589 ± 146 or 92%) and basal area (51 ± 13 or 88%) in the hilltop communities. In the understory of the canyon communities, there were five juvenile tree species including A. grandidentatum which had the fourth highest density (13% or 176 ± 110 plants/ha). In the hilltop communities, J. ashei was the high density understory tree species (52% or 994 ± 400 plants/ha). There were no A. Grandidentatum overstory or understory plants in the hilltop Juniperus communities. Acer grandidentatum had an inverse quadratic size distribution with few juveniles. Although we counted a number of seedlings, there was little recruitment over the last 16 years and very little potential recruitment in the previous 20 years. Juniperus ashei had an inverse exponential size distribution with many understory plants and considerable recruitment. Weibull age/size distributions showed one A. grandidentatum established in the 1670’s and 2 in the 1760’s, with peak establishment in the 1970’s. Causes of the lack of recent recruitment are uncertain, but it could be episodic due to changes in herbivory, management or other environmental conditions.

The Age Structure of a Larix gmelini Population and How It Was Related to Natural Disturbances

The age structure of a Lurix gmelini population in the northern part of the Great Xingan mountains consists of one to several age waves. Three types (one-, two- and multi-generation populations) , plusing eleven subtypes of age structure can be classified. As the basic unit of the age structure, age waves show an apparent β distribution in the range from 20 to 60 years. The interval between the starting points of two adjacent age waves is more than 100 years. Natural disturbances,especially forest fires that occurred in this area have had an important effect on the age structure. Most of the age waves resulted from forest fires, but the effect of windfall on the age structure also can be revealed through the analysis of young age waves. Generally, high intensity and low frequency fires are usually followed by one-generation populations, while low intensity and high frequency fires by two- or multi-generation populations.

Periodontal conditions and treatment in urban and rural population of West Bengal,India

Objective:To search adequate epidemiological data on periodontal conditions for the planning of oral health programs in Indian population,and to determine the prevalence of periodontal diseases,in regards to age and gender of urban and rural population in West Bengal.India. Methods:22 542 subjects aged 15 years onwards,representative of rural and urban areas of West Bengal were examined for their periodontal conditions using the community periodontal index(CPI).Results:Supra and/or sub gingival calculus dominated as the most frequent score (score 2) among males(76.51%) and females(76.58%),which was least affected in young age group and higher in rural population.Severity of highest score were significant(P【0.001) according to their gender,age group and habitation and had independent effects(P【0.001) on it. Mean number of sextants affected by scores 1,2,3,& 4 were more in the rural areas.Assessed treatment needed was predominantly typeⅡ(Scaling and improved oral hygiene).Conclusions: The severe periodontal condition(Score 2,3 and 4) is observed among rural males in older age group more than its urban counterparts of West Bengal,India.

Long-term monitoring data reveal effects of age,population density,and environmental aspects on hatching success of Common Cranes(Grus grus)

Facing climate and land use change,a species’ability to successfully adapt to changing environments is crucial for its survival.Extensive drainage and intensification of agriculture and forestry set wetlands and associated species at risk of population declines.The population of Common Cranes(Grus grus)has experienced considerable fluctuations over the last century.Despite increasing population numbers,hatching success seemed to have decreased over the last years.The aim of this study was to identify factors influencing hatching success and nest survival of Common Cranes based on analyses of long-term individual-based monitoring data from northeastern Germany and evaluate the species ability to adapt to changing environments.Hatching success decreased over the course of the study period from 0.75 to 0.55.Surprisingly,nest survival and hatching success did not vary across different nesting habitats,whereas factors such as female age,timing of nest initiation and breeding pair density were found to have significant effects on hatching success.Older females showed higher hatching success,even though the proportion of unhatched eggs was highest in females aged 20 years or older.Early nest initiation had a positive effect on hatching success.Water levels are more favorable early in the nesting season,whereas increasing evaporation with time causes water levels to decrease,granting easier access for predators.Independently of female age,hatching success decreased with increasing numbers of breeding pairs within a 2-km radius around a nesting site.High population densities intensify competition for resources and promote intraspecific interactions,affecting reproductive outcome negatively.This study gives first insights into mechanisms behind population regulation in Common Cranes,highlighting the importance of population dynamics and individual features.We suggest to further investigate density dependent effects including landscape and habitat features as well as reproductive success in terms of chick survival,since successfully raising juveniles is crucial for a species survival.

World Population Aged 60 and Over by Region

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Genotypic Diversity Affects Age Structure of Tiller and Rhizome of Leymus chinensis Population,But Not Age Structure of Bud

The effect of genotypic diversity on the age structure and bud bank of the Leymus chinensis population has not yet been demonstrated.This experiment was designed to study the age structure of the tiller,rhizome,and bud of L.chinensis at genotypic diversity levels of 1,2,4,8,and 12.A total of 64 communities were established in this experiment,following the principle of randomized block experimental design.The results indicated that genotypic diversity had a significant or obviously significant effect on the cumulative length of rhizomes of 2a and 4a,dry matter accumulation of rhizomes of 1a and 2a,tiller number of 1a,tiller productivity of 3a,but had no significant effect age structure of buds.As the levels of genotypic diversity increased,the proportion of the cumulative length of rhizomes with 4a decreased and then increased,and dry matter accumulation of rhizomes with 1a and 2a gradually increased while the number of tillers with 1a gradually decreased,when the gradient of genotypic diversity increased.At the 1,2,4,8,and 12 genotype diversity levels,the number of tillers,the cumulative length of rhizomes,and dry matter accumulation in rhizomes and buds were all age structures of expanding type.However,tiller productivity was an expanding or stable age structure at levels of 1,2,4,8 genotypic diversity,while it was a declining age structure at the 12 genotype diversity gradient.An appropriate genotypic diversity is conducive to maintaining the growth and stability of the age structure of L.chinensis population,but too high a gradient of genotypic diversity can have a negative impact on the population age structure.This study provided that an appropriate number of genotypic diversity contributes to the stability of the population.

Present Situation of China’s Aged Population

The population aged 60 and over in China reached 113.95.million.accounting for 9.43%of the total population,those aged65 and over for 6.41%。those aged 80 and over for 0.82%,according to data from the 1%national population sam-pling survey conducted on October 1 , 1995

The number of new Chinese population and the future evolution of population policy planning analysis

China as the world＇ s most populous country, the number of demographic change is an essential element of social development plan under consideration. This article combined with the background, based on the birth rate, mortality indicators as well as the corresponding changes in the age structure, demographic trends predict the future based on the current form of the economy analysis the population of 60 years since the founding of New China .China＇ s population control based on the complexity of the future still need to take tight family planning policy, change the mechanism of population control, optimize population structure, improve population quality.

Welfare for the Aged in Nigeria,a Sustenance for the Declining Older Population and Aged Male in Nigeria

A buttress on the need for welfare program in Nigeria and the important obligation to consider the Economics’and CIA’s contextual position for the dependency ratios,both total and elderly dependency ratio alongside the consideration of the age structure and demography statistics of Nigeria relatively to other economies,particularly as an elixir for the declining older population in Nigeria and the aged male contraction in the nation.Although,older female population is higher in every country as obtainable globally,the Nigerian case is that of drastic contraction in both aged male and older population generally.Therefore,the submission is that the government has to consider the total dependency ratio to the elderly dependency ratio,which is all-encompassing in order to cater for the declining older population and to appropriate the requisite welfare cum benefits programs in the nation.

Analysis on age structure of Zoysia japonica (Poaceae) population

The age-structure of natural population of Zoysia japonica in Xiuyan County of Liaoning Province was studied by generational method. The results showed that the highest tiller age class was three, but 1st age class tillers held dominant posi-tion with proportions over 95% in each month during the growing seasons. The 2nd age class and 3rd age class tillers were minority in the population. So Z. japonica population was an expanding population. The zero age class buds on the rhizomes were dominant in buds age structures. The proportion of buds to tillers on quantity in each month was about 30% to 40% and reached the highest at the end of September. The increasing of buds proportion before dormancy guaranteed the quantity of tillers in the next spring. The biomass of 1st age class tillers changed with time. The biomass kept increasing from April to July and reached the highest at the end of July and then decreased.

Comparative study on population age structures between Adenophora lobophylla and A. potaninii

Comparing with an affinity and widespread species Adenophora potaninii the age structures of A. loboPhylla population, an endangered plant species were studied. 29 sample plots were investigated in the centered distribution area, Jinchuan county from altitude 2 300 m to 3 400 m. The main factors which influence the population age structures of A. lobophylla were analyzed. The principal characteristics of A. lobophylla populations are that the number of seedling and the density of population are much less than these of A. potaninii population. Below aititude of 2 700 m, the age structures of most A. lobophylla populations show the declining status, only above altitude of 2 700 m they are stable, while age structures of all populations of A. potaninll populations at corresponding altitude perform stable and developing features. The age structure patterns, relations between age (X) and number of individual (y) of stable populations of A. lobophylla can be expressed by equation : y =e(a-bx), and the longest life spah is 25a. Whereas A. potaninii populations can be expressed by the equationf y =ax-b, and the longest life span of individual is 21a. The external factors, which constrain the extension of A. lobophylla population, are extreme environmental conditions such as serious drought, external disturbance and low temperature.

Annual Occurrence of Calanus sinicus Carcasses in the Jiaozhou Bay and the Adjacent Waters

The dead proportion of a calanoid copepod Calanus sinicus population was investigated monthly with neutral red staining method at 12 stations in the Jiaozhou Bay and the adjacent waters from December 2008 to November 2009. C. sinicus could be observed through the whole year, with an evident numerical peak from February to April and an extremely low abundance in summer. Annual variation of the dead proportion differed greatly between adult females and copepodites. Dead females were observed only in the southern part and outside the bay sporadically in five months, when the egg production was the most active. Dead proportion of females was usually less than 5%. Dead copepodites could be observed in all but three months in summer in the whole study area, and the proportion varied between 3.8% – 18.2%. Death percentage of copepodites increased significantly in the northern part in January and June, when water temperature exceeded it's favorable limits;however, the fluctuated salinity had no significant effect on the survival of both females and copepodites. Thus the dead proportion of C. sinicus was relatively low in the Jiaozhou Bay, while difference could be observed between females and copepodites. Dead copepodites were common in all samples, but dead females were presented mainly as ‘reproduction cost' during generation alternation.

Age scope of high-risk population for esophageal cancer in Ci county

AIM: To define the age scope of high-risk population for esophageal cancer (EC) in Ci county. METHODS: The results of endoscopic examination of 2 013 subjects, cytological screening of 16 763 persons and records of 9 265 patients with EC were analyzed by Ridit methods, the standard age group was 45-49 year group. RESULTS: The average age of patients with moderate esophageal epithelium dysplasia by endoscopic examination was 53.5 years, of severe esophageal epithelium dysplasia, 51.4 years, early EC, 55.6 years. The average age of stage one severe epithelium dysplasia (SEEDⅠ) by cytological screening was 51.2 years, of stage two severe epithelium esophageal dysplasia (SEED Ⅱ) 51.6 years, of advanced EC 61.7 years. In the group of 40-year olds, the value of Ridit by pathological diagnosis was 0.46, 95% CI, 0.45-0.47, that by cytological diagnosis was 0.45, 95% CI, 0.43-0.47. As the age increased at five-year intervals, the value of Ridit increased significantly. CONCLUSION: In Ci county of a high incidence area of EC, the age definition of high-risk population should be above 45 years.

Age-specific reference ranges of prostatespecific antigen in the elderly of Amirkola: A population-based study

Objective:To determine the age-specific reference ranges of prostate-specific antigen(PSA)in the older men in the city of Amirkola.Methods:This cross-sectional study is a part of Amirkola Health and Ageing Project(AHAP)which has been conducted as a cohort study since 2011 in Amirkola,a city in northern Iran.The demographic information of all men aged 60 and older were collected through questionnaires and interviews and the PSA measurements were performed using ELISA and Diametra kit.The acquired data were analyzed afterwards.Results:A number of 837 elderly men with a mean age of 69.99±7.72 years participated in this study.The serum PSA level(95th percentile)was determined to be 0.9(0-4.89)ng/mL in the age group of 60-64 years,1.1(0-4.88)ng/mL in the age group of 65-69 years,0.93(0-9.01)ng/mL in the age group of 70-74 years,1.3(0-7.95)ng/mL in the age group of 75-79 years,1.9(0-11.98 ng/mL)in the age group of 80-84 years,and 1.45(0-33.17)ng/mL in the 85 and older group.The serum PSA level was significantly correlated with age(p=0.000).Conclusion:This study indicated that there is a direct correlation between the age and serum PSA levels.The use of age-specific reference range could guide clinicians on the incidence of prostate cancer in this population and perhaps reduce the number of unnecessary tests in this population group.