An Approach to Modeling Crustacean Egg-Bearing Fractions as a Function of Size and Season

1991 ◽  
Vol 48 (8) ◽  
pp. 1431-1436 ◽  
Author(s):  
Victor R. Restrepo ◽  
Reg A. Watson

We present an approach to the analysis of crustacean egg production ogives with emphasis on detecting seasonal trends. The relationship between the proportion of gravid females (by size) and season is a prerequisite to the estimation of egg production potentials of populations. The basic method consists of relating, for each sample, the proportion of berried females with their size through a three-parameter logistic function where the asymptote may be less than 1. We then provide guidance for detecting seasonal trends in the estimates of the parameters for the individual samples. This is accomplished by restricting the basic model such that some parameters are considered to be either fixed for all samples or as simple functions of time or environmental variables such as temperature. Parameter estimates are obtained via maximum likelihood methods, and comparisons between alternative models are presented graphically and using likelihood ratio tests. We illustrate the approach and its application with data for a tropical shrimp, Penaeus esculentus, from northern Australia.

1991 ◽  
Vol 69 (8) ◽  
pp. 2085-2088 ◽  
Author(s):  
Edward P. Caswell ◽  
Ivan J. Thomason

Egg production by the sugarbeet cyst nematode, Heterodera schachtii, infecting sugarbeet, Beta vulgaris, was assessed at temperatures of 13, 18, 24, and 30 °C in constant-temperature tanks. The minimum-threshold temperature for degree-day accumulation relative to egg production was identified as 8 °C. The relationship between cumulative degree-days (DD) (base 8 °C) and egg production was examined. Egg production began between 160 and 270 DD after hatch and reached a maximum between 390 and 480 DD. Observed egg production (Y) across all temperatures was described as a logistic function of degree-days: Y = 202/(1 + 23726 e−0.034 DD) (r2 = 0.84; P < 0.05). The model depicts initiation of egg production at 140 DD, a maximum average egg production of 202 eggs per female reached at approximately 410 DD, and a maximum rate of egg production of 1.7 eggs/DD reached at approximately 290 DD. The accuracy of the model was limited because observed cumulative egg production was confounded by egg hatch. Accordingly, the cumulative egg production data were adjusted for egg hatch. The adjusted cumulative egg production (Y) was described as a logistic function of cumulative degree-days: Y = 420/(1 + 3319 e−0.023 DD) (r2 = 0.98; P < 0.05). The function depicts egg production initiated at approximately 120 DD. Average maximum egg production is 420 eggs per female occurring at approximately 680 DD, with a maximum egg-production rate of 2.4 eggs/DD occurring at approximately 350 DD.


1998 ◽  
Vol 55 (7) ◽  
pp. 1766-1783 ◽  
Author(s):  
C Tara Marshall ◽  
Olav Sigurd Kjesbu ◽  
Nathalia A Yaragina ◽  
Per Solemdal ◽  
Øyvind Ulltang

The assumption that spawner biomass is directly proportional to total egg production by fish stocks underlies most spawner-recruit relationships. Despite its importance, this assumption is largely untested. Data describing the reproductive potential of Northeast Arctic (NEA) Atlantic cod (Gadus morhua) were used to test the proportionality assumption for a period showing strong variation in condition and abundance of spawners. At the individual scale, relative fecundity varied with length and condition. This decreases the likelihood that the proportionality assumption is valid. At the stock level, total egg production was estimated (1985-1996) using acoustic estimates of total abundance and demographic information from trawl sampling in combination with year-specific fecundity-length relationships. For NEA cod, spawner biomass estimated by virtual population analysis (VPA) was not proportional to total egg production. Compared with VPA-based estimates of spawner biomass, total egg production is an improved index of recruitment potential because (i) the magnitude of variation observed in total egg production was closer to that observed in recruitment and (ii) the relationship between recruitment at age 1 and total egg production approaches the origin. The results suggest that further progress in explaining recruitment variation will be achieved using more sensitive measures of the true reproductive potential of the stock.


Author(s):  
Brynne D. Ovalle ◽  
Rahul Chakraborty

This article has two purposes: (a) to examine the relationship between intercultural power relations and the widespread practice of accent discrimination and (b) to underscore the ramifications of accent discrimination both for the individual and for global society as a whole. First, authors review social theory regarding language and group identity construction, and then go on to integrate more current studies linking accent bias to sociocultural variables. Authors discuss three examples of intercultural accent discrimination in order to illustrate how this link manifests itself in the broader context of international relations (i.e., how accent discrimination is generated in situations of unequal power) and, using a review of current research, assess the consequences of accent discrimination for the individual. Finally, the article highlights the impact that linguistic discrimination is having on linguistic diversity globally, partially using data from the United Nations Educational, Scientific and Cultural Organization (UNESCO) and partially by offering a potential context for interpreting the emergence of practices that seek to reduce or modify speaker accents.


Crisis ◽  
2016 ◽  
Vol 37 (4) ◽  
pp. 265-270 ◽  
Author(s):  
Meshan Lehmann ◽  
Matthew R. Hilimire ◽  
Lawrence H. Yang ◽  
Bruce G. Link ◽  
Jordan E. DeVylder

Abstract. Background: Self-esteem is a major contributor to risk for repeated suicide attempts. Prior research has shown that awareness of stigma is associated with reduced self-esteem among people with mental illness. No prior studies have examined the association between self-esteem and stereotype awareness among individuals with past suicide attempts. Aims: To understand the relationship between stereotype awareness and self-esteem among young adults who have and have not attempted suicide. Method: Computerized surveys were administered to college students (N = 637). Linear regression analyses were used to test associations between self-esteem and stereotype awareness, attempt history, and their interaction. Results: There was a significant stereotype awareness by attempt interaction (β = –.74, p = .006) in the regression analysis. The interaction was explained by a stronger negative association between stereotype awareness and self-esteem among individuals with past suicide attempts (β = –.50, p = .013) compared with those without attempts (β = –.09, p = .037). Conclusion: Stigma is associated with lower self-esteem within this high-functioning sample of young adults with histories of suicide attempts. Alleviating the impact of stigma at the individual (clinical) or community (public health) levels may improve self-esteem among this high-risk population, which could potentially influence subsequent suicide risk.


Author(s):  
Emma Simone

Virginia Woolf and Being-in-the-world: A Heideggerian Study explores Woolf’s treatment of the relationship between self and world from a phenomenological-existential perspective. This study presents a timely and compelling interpretation of Virginia Woolf’s textual treatment of the relationship between self and world from the perspective of the philosophy of Martin Heidegger. Drawing on Woolf’s novels, essays, reviews, letters, diary entries, short stories, and memoirs, the book explores the political and the ontological, as the individual’s connection to the world comes to be defined by an involvement and engagement that is always already situated within a particular physical, societal, and historical context. Emma Simone argues that at the heart of what it means to be an individual making his or her way in the world, the perspectives of Woolf and Heidegger are founded upon certain shared concerns, including the sustained critique of Cartesian dualism, particularly the resultant binary oppositions of subject and object, and self and Other; the understanding that the individual is a temporal being; an emphasis upon intersubjective relations insofar as Being-in-the-world is defined by Being-with-Others; and a consistent emphasis upon average everydayness as both determinative and representative of the individual’s relationship to and with the world.


2016 ◽  
pp. 45-49
Author(s):  
P.N. Veropotvelyan ◽  
◽  
I.S. Tsehmistrenko ◽  
N.P. Veropotvelyan ◽  
N.S. Rusak ◽  
...  

Was to conduct a systematic review of data on the relationship between polymorphisms genes of detoxification system and development of preeclampsia (РЕ). Рresents the main genes of detoxification system (GSTPI, GSTМI, GSTТI, GРХI, ЕРНХI, SOD-2, SOD-3, CYPIAL, MTHЕR, MTR) and their functions. Of interest is the possibility of calculating the individual risk of PE based on the results about the presence of a combination of different polymorphisms in the genotype of the female. Question about early diagnosis of РЕ remains controversial and not fully understood. It is necessary to conduct further in-depth, extended study of this problem. Key words: preeclampsia, oxidative stress, genes of the detoxification system.


2020 ◽  
Vol 8 (2) ◽  
Author(s):  
Prevan Moodley ◽  
Francois Rabie

Many gay couples engage in nonmonogamous relationships. Ideas about nonmonogamy have historically been theorised as individual pathology and indicating relational distress. Unlike mixed-sex couples, boundaries for gay couples are often not determined by sexual exclusivity. These relationships are built along a continuum of open and closed, and sexual exclusivity agreements are not restricted to binaries, thus requiring innovation and re-evaluation. Three white South African gay couples were each jointly interviewed about their open relationship, specifically about how this is negotiated. In contrast to research that uses the individual to investigate this topic, this study recruited dyads. The couples recalled the initial endorsement of heteronormative romantic constructions, after which they shifted to psychological restructuring. The dyad, domesticated through the stock image of a white picket fence, moved to a renewed arrangement, protected by “rules” and imperatives. Abbreviated grounded theory strategies led to a core category, “co-creating porous boundaries”, and two themes. First, the couple jointly made heteronormative ideals porous and, second, they reconfigured the relationship through dyadic protection. The overall relationship ideology associated with the white picket fence remained intact despite the micro-innovations through which the original heteronormative patterning was reconfigured.


2019 ◽  
Vol 5 (2) ◽  
pp. 32
Author(s):  
Gabriela E. Gui

In today’s America, not every child starts on a level playing field, and very few children move ahead based solely on hard work or talent. Generational poverty and a lack of cultural capital hold many students back, robbing them of the opportunity to move up professionally and socially. Children of immigrants are especially at-risk because, in addition to facing poverty, race, geographical location or economic disadvantages, they are also confronted with failure due to their limited or non-existent English proficiency. This study focuses on the degree to which teachers in a mid-sized urban school district take into consideration the individual needs of immigrant children in the process of their education. The study also examines the preparation teachers have had to equip them with knowledge of best practices in teaching immigrant children, and the relationship between teachers’ practices, beliefs, and their demographic and personal characteristics (age, gender, years of experience, level of education, etc.). Quantitative data was collected via a survey. Interviews with teachers and one central office administrator provided data for the qualitative section of the study. The findings revealed that teachers, in general, appeared to lack knowledge of specific policies for mainstreaming immigrant students into general education classrooms; their use of effective teaching practices for working with immigrant children were limited; and most of the teachers had not participated actively in professional development that focused on teaching immigrant children.


2020 ◽  
Vol 2 (4) ◽  
pp. 126-130
Author(s):  
N. V. SHAMANIN ◽  

The article raises the issue of the relationship of parent-child relationships and professional preferences in pedagogical dynasties. Particular attention is paid to the role of the family in the professional development of the individual. It has been suggested that there is a relationship between parent-child relationships and professional preferences.


Sign in / Sign up

Export Citation Format

Share Document