scholarly journals Variability of demographic parameters and population dynamics of Atlantic salmon Salmo salar L. in a south-west French river

2003 ◽  
Vol 60 (2) ◽  
pp. 356-370 ◽  
Author(s):  
J. Dumas ◽  
P. Prouzet

Abstract The abundance of the salmon population in the Nivelle River was assessed for 11 cohorts during all the stages of their life cycle, from eggs to spawners. A stochastic life history model was used to simulate the changes in numbers at each stage over several years and to evaluate the parameters of a Ricker-type Stock and Recruitment (S–R) relationship. Parameters necessary for managing the exploitation of the species were also estimated. The results indicated that an average deposition of 611 700 eggs (values varying in a proportion of 1 to 3, depending on the year) produced 4870 0+ parr in autumn (variation from 1 to 5.6); 71.8% of which belonged to the group of future 1-year old smolts. The age 1+ parr were eight times less numerous. Survival from egg to 0+ parr was on average 0.97%, but highly variable (varying from 1 to 15). It was density-dependent and followed Ricker S–R model with an optimum of 7800 parr for a survival rate of 3%. During their second year, the survival of 1+ parr reached 53.4% and varied little. The adult runs of complete cohorts amounted to 196 maiden salmon (range, 88 to 382) and previous spawners comprised only 0.9% of adults. Grilse (1 year in the sea) constituted the majority (88.7%). The overall survival rates from 0+ parr to adult returns (6.2% on average) varied three-fold. The majority was females among the grilse (56.2%) and 2-sea-year salmon (88.6%); all 3-sea-year adults were female. Eggs deposited per female averaged 4200, 8500 and 12 750 eggs in each age group, respectively. Simulations of population abundances at various life stages were in good agreement with the observed data. The S–R relationship revealed the low productivity and the vulnerability of this stock, mainly due to the low survival rate of the young during their first year of life. The maximum yield of 12.2% of recruits could be obtained from a deposition of 1 424 000 eggs, which is twice the present average level.

2020 ◽  
Vol 5 (1) ◽  
pp. 74-89
Author(s):  
Hugh Crago

In a seminal 1973 paper, Robert Clark described the very different “cultures” of the first and second year students in a four year clinical psychology PhD programme. The author applies Clark’s template to his own experiences as trainee or trainer in five different counsellor education programmes, one in the US and four in Australia. Each of the programmes, to varying degrees, demonstrates key features of the pattern identified by Clark, where the first year is “therapeutic” and other-oriented, the second is “professional” and self-focused. The author concludes that all the surveyed programmes exhibited some level of “second year crisis”, in which a significant number of students felt abandoned, dissatisfied, or rebellious. The author extends and refines Clark’s developmental analogy (first year = childhood; second year = adolescence) to reflect recent neurological research, in particular, the shift from a right hemisphere-dominant first year of life, prioritising affiliative needs, to a left hemisphere-dominant second year, prioritising autonomy and control. This shift is paralleled later by a more gradual move from a protective, supportive childhood to necessary, but sometimes conflictual, individuation in adolescence. The first two years of a counsellor training programme broadly echo this process, a process exacerbated by the second year internship/placement, in which students must “leave home” and adjust to unfamiliar, potentially less nurturing, authority figures. Finally, the author suggests introducing more rigorous “academic holding” into the first year, and greater attention to “therapeutic holding” of dissident students in the second, hopefully decreasing student dropout, and achieving a better balanced training experience.


1992 ◽  
Vol 2 (12) ◽  
pp. S228
Author(s):  
J S Najarian ◽  
P S Almond ◽  
M Mauer ◽  
B Chavers ◽  
T Nevins ◽  
...  

The treatment of choice for end-stage renal failure within the first year of life is controversial. Between September 1970 and February 1991, we performed 28 kidney transplants (27 primary, 1 retransplant, 23 living donor, 5 cadaver) in infants less than 1 yr of age (mean, 7 +/- 2 months; range, 6 wk to 12 months). The 1-yr patient survival rate for living donor recipients was 100% versus 20% for cadaver recipients (P = 0.0001). The 1-yr graft survival rate for living donor recipients was 96% versus 20% for cadaver recipients (P = 0.001). The 1-yr patient survival rate for cyclosporin A (CSA) recipients (N = 12) was 100% versus 75% for non-CSA recipients (P = 0.03). The 1-yr graft survival rate for CSA recipients was 92% versus 75% for non-CSA recipients (P = 0.08). There was no difference in the number of rejection episodes or serum creatinine levels in CSA versus non-CSA recipients. Compared with pretransplant values, the mean posttransplant standard deviation scores (SDS) for height (N = 18), weight (N = 22), and head circumference (N = 8) improved: height SDS from -1.9 to -1.5 (not significant); weight SDS from -2.5 to 0.6 (P less than 0.0005); head circumference SDS from -2.0 to -0.7 (P = 0.01). Because no other renal replacement therapy can match these results, we conclude that renal transplantation is the treatment of choice for infants with end-stage renal failure.


Author(s):  
Svetlana Vasil'evna Ivanova ◽  
Olga Vasil'evna Kurdakova ◽  
Aminat Msostovna Konova ◽  
Anna Yurievna Gavrilova

In the course of the experiment, the effect of increasing doses of nitrogen fertilizers on the yield of clover of the meadow variety Nadezhny, entered in the State Register of Breeding Achievements in 2012, was analyzed. A comparison is also made of this influence with the timothy of the meadow variety Leningradskaya 204. It was established that the pre-sowing introduction of mineral nitrogen for clover and timothy has influenced the productivity of these crops, but the nature of this effect varies depending on the type of grass. The introduction of N20 against the background of P30K90, which provided an increase in control of 51.2% for green mass and 33.6% for air-dry matter, was optimal for meadow clover of the first year of life. For grassland clover second year of life, the best option was N0P30K90, which gave an increase of 56.6% to the control on green mass and 50.6% on air-dry matter. A further increase in the dose of nitrogen on the options caused a decrease in yield increase. Timothy meadow for two years of life was traced responsiveness to the provision of nitrogen. The most productive in all respects was the option N120P30K90.    


Author(s):  
Serhat Ayas

This trial was realized in the greenhouses of Uludağ University Yenişehir Vocational School between 2009 and 2010 to investigate effects of water deficit on yield and quality parameters of onion during four crop growth stages. In this trial, fourteen irrigation treatments in four growth periods (establishment, vegetative, yield formation and ripening) of onion (Allium cepa L E.T Grano.502) were constituted and the yield and quality parameters found from these treatments were evaluated. The layout of the experiment was a completely randomized block design with three replications for each of the fourteen irrigation treatments tested. According to the content of the treatments, the irrigation amount water applied to the plants varied between 0 and 436 mm in the first year, and between 0 and 448 mm in the second year. Water consumption of onion in the first year ranged between 205 and 496 mm and in the second year ranged between 210 and 502 mm. Yield, bulb weight, diameter, height and dry matter ratio were determined statistically significant. In 2009 and 2010 years, the maximum yield were found as 52.2 t ha-1 and 52.4 t ha-1 in E100V100Y100R100 treatments, while the minimum yield were found as 0.8 t ha-1 and 0.5 t ha-1 in the E0V0Y0R0 treatments, respectively. Water- yield relationship factors (ky) in 2009 and 2010 years were found as 1.03 and 1.04, respectively. The maximum WUE and IWUE values were obtained from establishment and ripening periods. Establishment and ripening periods may be suggested as the maximum efficient irrigation periods for the onion applied with drip irrigation under unheated greenhouse conditions.


Author(s):  
Elaine Espino Barr ◽  
Manuel Gallardo Cabello ◽  
Fernando González Orozco ◽  
Arturo Garcia Boa

This paper deals with the growth and mortality analysis of the burrito grunt A n i s o t remus interru p t u s on the coast of Colima, México. The estimated growth parameters are: L¥ = 50.59 cm; W¥ = 5,051.04 g; k = 0.147 years- 1; to = -0.916 years; A0 . 9 5 = 19.46 years. Most of the growth occurred during the first year of life, when the grunt grows 12.52 cm, the second year it grows 4.95 cm and the third, 4.60 cm. The highest value of the condition index took place between February and September. The total mortality rate (Z) was calculated as 0.53 years- 1. These values are basic for the plan of administration of the fishery of this species.


Nutrients ◽  
2018 ◽  
Vol 10 (8) ◽  
pp. 1124 ◽  
Author(s):  
Sergio Verd ◽  
Gemma Ginovart ◽  
Javier Calvo ◽  
Jaume Ponce-Taylor ◽  
Antoni Gaya

The aim of this review is to evaluate changes in protein parameters in the second year postpartum. There is considerable agreement among authors about the declining trend of human milk protein concentrations, but most research on protein content in breast milk focuses on the first year of life and comes from developed countries. Whereas this is the case for exclusive breastfeeding or for breastfeeding into the first year of life, the opposite applies to weaning or extended breastfeeding. This review is predominantly based on observational epidemiological evidence and on comparative research linking breast milk composition with cutting down on breastfeeding. Studies dating back several decades have shown an increase in the proportion of immunoglobulins, lactoferrin, and serum albumin during weaning. According to the limited data available, it seems likely that the regulation of milk protein composition during involution can be ascribed to alterations in tight junctions. In studies on humans and other mammalian species, offspring suckle more from mothers that produce more dilute milk and the increase in milk protein concentration is positively correlated to a decrease in suckling frequency during weaning. High milk protein contents were first reported in nonindustrial communities where breastfeeding is sustained the longest, but recent papers from urbanized communities have taken credit for rediscovering the increase in protein content of human milk that becomes evident with prolonged breastfeeding. This review presents an overview of the changes in breast milk protein parameters in the second year postpartum to enable milk banks’ practitioners to make informed nutritional decisions on preterm infants.


PEDIATRICS ◽  
1952 ◽  
Vol 9 (5) ◽  
pp. 648-650
Author(s):  
C. COLLINS-WILLIAMS

ACCIDENTS, at the present time, are one of the principal causes of death, particularly among children. In Canada approximately 1,500 children die each year as the result of accidents, a mortality greater than that due to the 10 acute infectious diseases of childhood combined. During the five year period 1942-46 inclusive, in Canada, accidents stood in eighth place as a cause of death during the first year of life, in third place during the second year, and in first place during each year after infancy up to the fifteenth birthday. During the same period, 21% of the deaths between the first and fifteenth birthdays were due to accidents. In this age of preventive medicine when our chief purpose as physicians is the prevention of morbidity and mortality, we, as pediatricians, cannot neglect this extremely important phase of child care. In any campaign to reduce the number of accidents, there are three ways in which the physician can play an important part. Firstly, the general public must be made aware of the seriousness of the situation and must be educated in the ways in which they, as citizens and parents, can help to reduce accidents. Secondly, the medical profession, working through its associations and publications, must stimulate all physicians to a concerted effort to reduce the number of accidents. Finally, and most important, the physician must concentrate on an educational program for his own private patients. A few words from the physician who looks after the child will do more to impress parents than will reams of propaganda published by someone unknown to them.


The Auk ◽  
2007 ◽  
Vol 124 (3) ◽  
pp. 815-827
Author(s):  
Leesa A. Sidhu ◽  
Edward A. Catchpole ◽  
Peter Dann

Abstract We analyzed yearly mark-recapture-recovery information collected over a 36-year period for the Little Penguins (Eudyptula minor) of Phillip Island in southeastern Australia. We show that it is feasible to model age-dependence for the survival, recapture, and recovery probabilities simultaneously, and that such a modeling scheme yields biologically realistic age structures for the model parameters. We provide illustrations of potentially erroneous results that may arise when researchers fail (1) to consider simultaneous age-dependence or (2) to detect annual variations that may mask age-dependence. From 1968 to 2004, 23,686 chicks were flipper-banded; 2,979 birds were encountered after fledging, and 1,347 were ultimately recovered dead. We found low survival of 17% in the first year of life, increasing to 71% in the second year of life, 78% in the third year, and 83% thereafter, and declining gradually after nine years of age. A population model allowing for immigration of birds from areas surrounding the study sites fits the observed stable population in the study sites. Modelado de Marca-Recaptura-Recuperación y Supervivencia Relacionada con la Edad en Eudyptula minor


2019 ◽  
Vol 28 (3) ◽  
pp. 274-279 ◽  
Author(s):  
Audun Dahl ◽  
Celia A. Brownell

From early in life, children help, comfort, and share with other people. Recent research has deepened scientific understanding of the development of prosociality—efforts to promote the welfare of others. In this article, we discuss two key insights about the emergence and early development of prosocial behavior, focusing on the development of helping. First, children’s motivations and capabilities for helping change in quality as well as quantity over the opening years of life. Specifically, helping begins in participatory activities without prosocial intent in the first year of life, becoming increasingly autonomous and motivated by prosocial intent over the second year. Second, helping emerges through bidirectional social interactions starting at birth: Caregivers and other individuals support the development of helping in a variety of ways, and young children play active roles that often influence caregiver behavior. The question now is not whether but how social interactions contribute to the development of prosocial behavior. Recent methodological and theoretical advances provide exciting avenues for future research on the social and emotional origins of human prosociality.


1995 ◽  
Vol 73 (7) ◽  
pp. 1312-1322 ◽  
Author(s):  
S. C. Amstrup ◽  
G. M. Durner

Polar bears (Ursus maritimus) are hunted throughout most of their range. In addition to hunting, polar bears of the Beaufort Sea region are exposed to mineral and hydrocarbon extraction and related human activities such as shipping, road building, and seismic testing. As human populations increase and demands for polar bears and other arctic resources escalate, reliable estimates of survivorship of polar bears are needed to predict and manage the impacts of those activities. We used the Kaplan–Meier model to estimate annual survival (with 95% confidence intervals) for radio-collared female polar bears and their dependent young that were followed during a 12-year study in the Alaskan Beaufort Sea. Survival of adult female polar bears was higher than had been previously thought: Ŝ = 0.969 (range 0.952–0.983). If human-caused mortalities were deleted, the computed survival rate was 0.996 (0.990–1.002). Survival of young from den exit to weaning was 0.676 (0.634–0.701). Survival during the second year of life, 0.860 (0.751–0.903), was substantially higher than during the first year, 0.651 (0.610–0.675). Shooting by local hunters accounted for 85% of the documented deaths of adult female polar bears. Conversely, 90% of documented losses of young accompanying radio-collared females were not directly caused by humans. Deaths of dependent young were independent of litter size (P = 0.36), indicating that parental investment in single cubs was not different from investment in litters of two or more. Precise estimates of the survival of independent juveniles and adult males still need to be developed.


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