Dispersal of the collembolan, Folsomia Candida Willem, as a function of age

1983 ◽  
Vol 61 (11) ◽  
pp. 2534-2538 ◽  
Author(s):  
D. L. Johnson ◽  
W. G. Wellington

The tendency of Folsomia Candida to disperse varies with age. In laboratory experiments, the youngest individuals rarely moved from the release sites in dispersal trays, while the older F. Candida showed a tendency to move into more distant areas. Distance travelled is an approximately linear function of body length, and length is a power function of age in this species. The same linear relationship between dispersal and age was apparent over short (2 h) and long (24 h) dispersal periods. When food was present on the release site, the dispersive behavior of the youngest and the oldest classes was unchanged. However, the presence of food restricted travel of medium-sized springtails, many of which remained in the release site to feed. Since these young adults begin oviposition while still growing at a relatively high rate, their food requirements are higher than younger and older springtails. This change in behavior significantly altered the relationship between size and distance travelled. In natural situations, it is advantageous for the youngest individuals to remain in the area in which they hatched, where ample food and moisture are likely to be found. Because of their greater tendency to disperse, the older individuals spread their eggs over a larger area.

1998 ◽  
Vol 8 (1) ◽  
pp. 1 ◽  
Author(s):  
NP Cheney ◽  
JS Gould ◽  
WR Catchpole

This pager describes a model to predict fire spread in grasslands from wind speed at 10 m, dead fuel moisture, and degree of grass curing in three defined pasture types, The model was developed from spread measurements of experimental fins that were adjusted to their potential rate of spread at wide fronts. Extrapolations of the model were compared with spread data from 20 major wildfires in Australia. This model uses different functions to describe the relationship between rate of spread and wind speed above and below a critical wind speed of 5 km h-1. A linear relationship is used below 5 km h-1; above 5 km h-1 rate of spread is described by a power function of wind speed with an exponent of less than 1.


2017 ◽  
Vol 2 (15) ◽  
pp. 32-41
Author(s):  
Jennine Harvey ◽  
Scott Seeman ◽  
Deborah von Hapsburg

The field of Cognitive Hearing Science examines the relationship between cognitive, linguistic, and hearing functions. Although these areas are of particular importance to speech-language pathology, few studies have investigated applications of cognitive hearing science to clinical practice. The purpose of this review article is to (1) explore and present a summary of cognitive hearing science techniques for dual-task and hearing-in-noise procedures and implications to speech-language pathology, and (2) provide a clinical guide for speech-language pathology in adult multitasking intervention with noise. It is well understood that areas of cognitive skill and hearing function decline with age; therefore, additional understanding of the relationship of these functions is of particular importance to speech-language pathologists working with older individuals. This article meets the American Speech-Language-Hearing Association's (ASHA's) Special Interest Group (SIG) 15's mission of “research-to-practice” professional development by “promoting understanding of the effects of normal and pathological aging on cognition, language […] and hearing” (ASHA, 2017), and is intended to be of interest to the SIG 15 readership.


Author(s):  
Marc Allroggen ◽  
Peter Rehmann ◽  
Eva Schürch ◽  
Carolyn C. Morf ◽  
Michael Kölch

Abstract.Narcissism is seen as a multidimensional construct that consists of two manifestations: grandiose and vulnerable narcissism. In order to define these two manifestations, their relationship to personality factors has increasingly become of interest. However, so far no studies have considered the relationship between different phenotypes of narcissism and personality factors in adolescents. Method: In a cross-sectional study, we examine a group of adolescents (n = 98; average age 16.77 years; 23.5 % female) with regard to the relationship between Big Five personality factors and pathological narcissism using self-report instruments. This group is compared to a group of young adults (n = 38; average age 19.69 years; 25.6 % female). Results: Grandiose narcissism is primarily related to low Agreeableness and Extraversion, vulnerable narcissism to Neuroticism. We do not find differences between adolescents and young adults concerning the relationship between grandiose and vulnerable narcissism and personality traits. Discussion: Vulnerable and grandiose narcissism can be well differentiated in adolescents, and the pattern does not show substantial differences compared to young adults.


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.


2016 ◽  
Vol 37 (2) ◽  
pp. 128-134 ◽  
Author(s):  
Elizabeth B. Lozano ◽  
Mahzad Hojjat ◽  
Judith Sims-Knight

Abstract. The present study examined the relationship between resilience and positive outcomes in friendships of young adults. SEM and bootstrapping analyses were performed to test whether positive emotions mediate the relationship between ego-resilience and enhanced friendship outcomes. Findings revealed indirect effects for friendship closeness, maintenance behaviors, and received social support. Our findings demonstrate the importance of positive emotions and its connection with trait resilience in the realm of friendships.


1990 ◽  
Vol 21 (4) ◽  
pp. 283-300 ◽  
Author(s):  
Anoel Rinaldi ◽  
Michael C. Kearl

This research examines a social service devoted to “good deaths” in our country: hospice. Using a modified Delphi technique, a national sample of hospice experts ( n = 48) was questioned in order to elicit group judgments about hospice ideology, the issue of control over one's own death trajectory, and hospice's relevance for older individuals. The respondents generally concurred that hospice, influenced by the work of Kübler-Ross, represents a radical departure in how we die, a reaction to the quality of death within a cultural climate of death denial, and, in some sense, a demodernization movement. While a high rate of consensus was obtained on many of the issues that evolved, little evidence of a coherent ideology could be detected linking notions of hospice origins, issues of patient control, and suitability of hospice care for older individuals.


Mathematics ◽  
2021 ◽  
Vol 9 (13) ◽  
pp. 1568
Author(s):  
Shaul K. Bar-Lev

Let F=Fθ:θ∈Θ⊂R be a family of probability distributions indexed by a parameter θ and let X1,⋯,Xn be i.i.d. r.v.’s with L(X1)=Fθ∈F. Then, F is said to be reproducible if for all θ∈Θ and n∈N, there exists a sequence (αn)n≥1 and a mapping gn:Θ→Θ,θ⟼gn(θ) such that L(αn∑i=1nXi)=Fgn(θ)∈F. In this paper, we prove that a natural exponential family F is reproducible iff it possesses a variance function which is a power function of its mean. Such a result generalizes that of Bar-Lev and Enis (1986, The Annals of Statistics) who proved a similar but partial statement under the assumption that F is steep as and under rather restricted constraints on the forms of αn and gn(θ). We show that such restrictions are not required. In addition, we examine various aspects of reproducibility, both theoretically and practically, and discuss the relationship between reproducibility, convolution and infinite divisibility. We suggest new avenues for characterizing other classes of families of distributions with respect to their reproducibility and convolution properties .


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