Testing hypotheses concerning the formation of shell growth marks in marine pelecypods

1991 ◽  
Vol 69 (3) ◽  
pp. 535-546 ◽  
Author(s):  
Edwin Bourget ◽  
Hélène Bérard ◽  
Vibeke Brock
Keyword(s):  
Shell Growth ◽  
Growth Accounting ◽  
Short Term ◽  
Tidal Period ◽  
Growth Increments ◽  
Potential Sources ◽  
Sources Of Variation ◽  
Shell Deposition ◽  
The Individual ◽  
External Growth

This paper reviews the evidence supporting the current hypotheses (daily, tidal, endogenous, and other rhythms of growth) accounting for short-term periodicity in the formation of marks (external growth ridges and internal growth increments) on the shell of marine pelecypod molluscs. With few exceptions our analysis shows too much unexplained variability and the availability of too few studies of potential sources of variation for the proposed cycles of mark formation (circadian, circatidal) to be accepted. Since shell deposition takes the form of marks, which must be discrete in frequency (0, 1, or 2 per given day or tidal period), we submit that individual frequencies must be used to test hypotheses concerning the rhythms of shell growth mark formation, and we propose the use of three criteria: (i) that departure of the individual measured frequency from the expected frequency should not be more than the maximal error in measurements (maximal counting errors made by the observer); (ii) should condition one be violated, then the so-called "missing" or "superfluous" marks should be clearly accounted for; (iii) that potential sources of variation (e.g., age, habitat, locality, season) should not significantly influence the frequency of formation of the marks.

Determination of allostatic load dynamics in the assessment of adaptation in temporary workers in the Arctic

2020 ◽  
pp. 547-548
Author(s):  
O. Yu. Atkov ◽  
S. G. Gorokhova
Keyword(s):  
Body Mass Index ◽  
Glucose Level ◽  
Shift Work ◽  
Allostatic Load ◽  
The Arctic ◽  
Temporary Workers ◽  
Short Term ◽  
Short Term Adaptation ◽  
The Individual

The individual dynamics of the allostatic load index was revealed mainly due to changes in the glucose level, body mass index, which makes it applicable for assessing the short-term adaptation to the stay in the conditions of shift work

Co-operation as a Conditional Strategy among Peers: Influence of Social Ecology and Kin Relations

1996 ◽  
Vol 19 (1) ◽  
pp. 39-52 ◽  
Author(s):  
Peter J. LaFreniere
Keyword(s):  
Peer Relations ◽  
Research Programme ◽  
Conditional Strategy ◽  
Social Unit ◽  
Kin Relations ◽  
Sources Of Variation ◽  
The Individual ◽  
Developmental Significance ◽  
The Relationship

The goal of this study is to analyse sources of variation, residing within the individual or within the relationship, in the ability to balance co-operative and competitive behaviours in a dyadic context. The ability to balance these two tendencies can be considered fundamental to successful adaptation within a social unit because co-operation may be essential in raising offspring, competing with other groups or in generating resources, whereas egoistic behaviour may protect the individual from exploitation or otherwise enhance reproductive success. Research is reviewed on the influence of social structures and relationships on co-operation in peer groups, and the origin and developmental significance of individual differences in co-operative abilities. Finally, a research programme investigating the conjunction of kin and peer relations is described, emphasising the role of affective synchrony, behavioural contingency, and reciprocity in shaping and sustaining co-operative behaviour as a conditional strategy.

Social trust, norms and morality

Human Affairs ◽  
2013 ◽  
Vol 23 (3) ◽  
Author(s):  
Miroslav Popper
Keyword(s):  
Social Capital ◽  
Political Institutions ◽  
Social Trust ◽  
Local Level ◽  
Dynamic Change ◽  
Short Term ◽  
Legal Norms ◽  
Increased Sensitivity ◽  
The Individual

AbstractThe article approaches the topic of social trust from an evolutionary perspective. It begins by summarising the most influential approaches that have defined specific and social trust and ascertains what causes differences in degrees of trust and how the potential risk of deception might be lowered. It then notes that the basis of morality had already been formed during the era of prehistoric man, who was able to create coalitions against aggressors and to socially control the behaviour of deviants. It points out, however, that having a certain predisposition to behaving cooperatively or an increased sensitivity to recognising and not tolerating behaviour aimed at abusing cooperation is not a sufficient guarantee of the fact that people will always (or at least in the majority of situations) favour cooperation over deception. One of the reasons for this is a tendency to favour short-term gains over long-term ones. The article argues that establishing norms (moral, social and legal) produces a higher level of social trust because it not only “encourages” individuals to behave in certain ways in particular situations but also works as a sanction which “discourages” the individual from socially deviant behaviour. The article then focuses on a debate about the causal relationship between social trust and social capital. It discusses the suggestion that political institutions, government and the judiciary may reduce rather than raise levels of social capital and consequently also the level of social trust. This is partly because of their powerful position and the consequent scope for corruption and partly because of the fact that even when attempting to act honestly, representatives of these institutions cannot sufficiently reflect upon dynamic change at the local level. Finally, the article ends by adopting the position that social trust is built primarily from bottom up and so it is risky to continually doubt the very existence and usefulness of social norms and morality and to be governed simply by legal norms.

CLINICAL PROFILE OF PATIENTS OF YOUNG STROKE.

2021 ◽  
pp. 68-70
Author(s):  
Nitin Hiraman Suryawanshi ◽  
Amit Aggarwal ◽  
Abhijit Kadam
Keyword(s):  
Diabetes Mellitus ◽  
Risk Factors ◽  
Young Patients ◽  
Behavioural Pattern ◽  
Long Term Outcomes ◽  
Short Term ◽  
Traditional Risk Factors ◽  
The Individual ◽  
Stroke In Young

A study of stroke in young patients has recently become a subject of interest. This is due to a lot of impact on the individual and society. Study of stroke in young patients can lead to therapeutical results affecting both short term and long-term outcomes. Our study is hospital based retrospective study for duration of 1 year. Thi Methods: Results: s study revealed stroke in young in 25.16% of all stroke cases, with cerebral infarction in 56% and followed by intracerebral haemorrhage in 25.64%, and cerebral venous thrombosis in 18%. The most common presenting symptom was hemiparesis. The most prevalent risk factor for stroke in young was hypertension followed by diabetes mellitus, alcohol consumption and smoking. Stroke in young requires a differe Conclusion: nt approach to investigate and treat. This is due to different underlying etilogy as compared to elderly. Although traditional risk factors are associated with stroke, behavioural pattern such as smoking and alcohol may cause and promote development of stroke in young.

HEART RATE VARIABILITY RELATED TO N95 RESPIRATOR USE IN INTERNS DURING COVID-19 PANDEMIC

2021 ◽  
pp. 69-70
Author(s):  
Pakanati Sujana ◽  
Venkata Mahesh Gandhavalla ◽  
K. Prabhakara Rao
Keyword(s):  
Heart Rate ◽  
Heart Rate Variability ◽  
Low Frequency ◽  
Protective Equipment ◽  
Short Term ◽  
Non Invasive ◽  
Critical Components ◽  
The Individual ◽  
N95 Respirators ◽  
Respiratory Droplets

Introduction: COVID19 is caused by SARS-CoV-2 which is primarily transmitted through respiratory droplets and contact routes. WHO recommended the use of personal protective equipment (PPE) for prevention and N95 respirators are critical components of PPE. Breathing through N95 respirator will impart stress in the individual and that can be assessed by heart rate variability (HRV). HRV measures the variation in time between each heartbeat controlled by autonomic nervous system (ANS), which is a non invasive reliable index to identify the ANS imbalances. Aims And Objectives: This study is aimed at assessing the HRV of Interns working in COVID19 wards using N95 respirators. Methodology: This study included 100 interns in whom short term HRV was recorded using the standard protocol. Lead II of ECG was recorded using AD instruments (ADI) 8channel polygraph and HRV was analysed using Labchart 8pro software. The recordings were taken before and 1hour after wearing N95 respirator. Results: Overall HRV (SDRR) was found to decrease signicantly after wearing N95 respirator for 1hr (p=0.000). Similarly, indices representing the parasympathetic component ( RMSSD and HF ) were also found to decrease signicantly with the use of N95 respirator. Low frequency (LF) power and LF/HF ratio increased signicantly with N95 respirator use (p=0.000). Conclusion: We conclude that using N95 respirator increased sympathetic activity reecting decreased HRV in our subjects Hence we recommend that it is better to change the duty pattern for interns.

scholarly journals The prevalence of extra-lethal violence across cultures in warfare

2017 ◽  
Author(s):  
◽  
Aaron Z. Johnson
Keyword(s):  
Cultural Analysis ◽  
Cross Cultural ◽  
Costly Signaling ◽  
Human Relations ◽  
Short Term ◽  
Direct Benefit ◽  
Lethal Violence ◽  
Individual Level ◽  
The Individual ◽  
Decisive Advantage

Extra-Lethal Violence, a form of physical aggression that goes beyond the necessity to kill someone, presents a conundrum: it is inefficient and dangerous to produce, especially during warfare. Extra-Lethal Violence, particularly when it manifests in warfare, does not contribute to the immediate survival of individuals; the time, effort, and lack of awareness of surroundings or other attack suggests that Extra-Lethal Violence could be maladaptive at the individual level or in the short term. Yet this individually risky behavior that seems to have no direct benefit to the aggressor is both common and persistent across time and space. We utilized the electronic Human Relations Area Files (HRAF) to conduct a cross cultural analysis of the prevalence and potential predictors of Extra-Lethal Violence. Our research indicates that Extra-Lethal Violence is present across all populated regions of the world, for the entire timespan of the ethnographic record up to the ethnographic present, across subsistence, marriage, and social complexity levels. Our research suggests that Costly Signaling Theory (CST) is currently the best explanation for this behavior. Extra-Lethal Violence can be characterized as a difficult to fake, clear indicator of martial skill and physical fitness that has a high broadcast efficiency, both within and between groups. Rather than allowing behaviors such as Extra-Lethal Violence to be labeled as 'abhorrent' or 'disgusting,' we must view Extra-Lethal Violence in the same light as the cavalry, the ironclads, or nuclear weapons: societies seeking a decisive advantage over their enemies, utilizing available resources, be they material or behavioral.

scholarly journals Kecerdasan Emosi Dan Depresi Pada Mahasiswa Yang Sudah Menikah

2019 ◽  
Vol 6 (2) ◽  
pp. 146
Author(s):  
Azizah Fitriah
Keyword(s):  
Emotional Intelligence ◽  
Hypothesis Test ◽  
Negative Relationship ◽  
Field Research ◽  
Short Term ◽  
Significant Negative Relationship ◽  
Correlational Approach ◽  
The Individual ◽  
Married Students ◽  
The Relationship

Every human being will one day experience a tense period in the short term when facing known problems such as career pressures, family disputes or quarrels, material pressures, and personal despair, and we will think that this is depression, which is not is an important problem because it will resolve itself, but none of these fleeting conditions is depression. Good emotional intelligence can reduce aggression, especially in adolescents. Therefore, if emotions are managed successfully, the individual will be able to entertain themselves when overwritten by sadness, can release anxiety, moodiness or offense and rise quickly again from it all. This research is field research with a correlational approach, exploring the relationship between depression and emotional intelligence in married students. The results of the hypothesis test show that between emotional intelligence and depression in married students has a significant negative relationship (XY = -0.411; sig = 0.014 <0.05). This is in accordance with the data obtained from the SPSS 19 for Windows program, stating that r table 0.334 and r xy (r hit) -0.411, said to be significant if r xy = 0.411> r table = 0.334. In other words, the higher the emotional intelligence of students who are married, the lower the possibility of depression.

scholarly journals Bivalves rapidly repair shells damaged by fatigue and bolster strength

2021 ◽  
Vol 224 (19) ◽  
Author(s):  
R. L. Crane ◽  
J. L. Diaz Reyes ◽  
M. W. Denny
Keyword(s):  
Shell Growth ◽  
Fatigue Loading ◽  
Epifluorescence Microscopy ◽  
Mytilus Californianus ◽  
Environmental Threats ◽  
Rapid Repair ◽  
Shell Deposition ◽  
Repetitive Loading ◽  
Plastic Changes ◽  
Mussel Shells

ABSTRACT Hard external armors have to defend against a lifetime of threats yet are traditionally understood by their ability to withstand a single attack. Survival of bivalve mollusks thus can depend on the ability to repair shell damage between encounters. We studied the capacity for repair in the intertidal mussel Mytilus californianus by compressing live mussels for 15 cycles at ∼79% of their predicted strength (critically fracturing 46% of shells), then allowing the survivors 0, 1, 2 or 4 weeks to repair. Immediately after fatigue loading, mussel shells were 20% weaker than control shells that had not experienced repetitive loading. However, mussels restored full shell strength within 1 week, and after 4 weeks shells that had experienced greater fatiguing forces were stronger than those repetitively loaded at lower forces. Microscopy supported the hypothesis that crack propagation is a mechanism of fatigue-caused weakening. However, the mechanism of repair was only partially explained, as epifluorescence microscopy of calcein staining for shell deposition showed that only half of the mussels that experienced repetitive loading had initiated direct repair via shell growth around fractures. Our findings document repair weeks to months faster than demonstrated in other mollusks. This rapid repair may be important for the mussels’ success contending with predatory and environmental threats in the harsh environment of wave-swept rocky coasts, allowing them to address non-critical but weakening damage and to initiate plastic changes to shell strength. We highlight the significant insight gained by studying biological armors not as static structures but, instead, as dynamic systems that accumulate, repair and respond to damage.

scholarly journals EXPRESS: Sources of Variation In Search and Foraging A Theoretical Perspective

2021 ◽  
pp. 174702182110503
Author(s):  
Alastair David Smith ◽  
Carlo De Lillo
Keyword(s):  
Spatial Scales ◽  
Theoretical Perspective ◽  
Search Space ◽  
Visual Exploration ◽  
Two Dimensional ◽  
Search Behaviour ◽  
Wide Range ◽  
Search Processes ◽  
Sources Of Variation ◽  
The Individual

Search – the problem of exploring a space of alternatives in order to identify target goals – is a fundamental behaviour for many species. Although its foundation lies in foraging, most studies of human search behaviour have been directed towards understanding the attentional mechanisms that underlie the efficient visual exploration of two-dimensional scenes. With this review, we aim to characterise how search behaviour can be explained across a wide range of contexts, environments, spatial scales, and populations, both typical and atypical. We first consider the generality of search processes across psychological domains. We then review studies of interspecies differences in search. Finally, we explore in detail the individual and contextual variables that affect visual search and related behaviours in established experimental psychology paradigms. Despite the heterogeneity of the findings discussed, we identify that variations in control processes, along with the ability to regulate behaviour as a function of the structure of search space and the sampling processes adopted, to be central to explanations of variations in search behaviour. We propose a tentative theoretical model aimed at integrating these notions and close by exploring questions that remain unaddressed.

scholarly journals Fiber tractography bundle segmentation depends on scanner effects, acquisition, diffusion sensitization, and bundle segmentation workflow

2021 ◽  
Author(s):  
Kurt Schilling ◽  
Chantal M.W. Tax ◽  
Francois Rheault ◽  
Colin B Hansen ◽  
Qi Yang ◽  
...  
Keyword(s):  
White Matter ◽  
Mean Diffusivity ◽  
B Value ◽  
Fiber Tractography ◽  
Acquisition Protocol ◽  
Segmentation Methods ◽  
Combining Data ◽  
Potential Sources ◽  
Sources Of Variation ◽  
The Brain

When investigating connectivity and microstructure of white matter pathways of the brain using diffusion tractography bundle segmentation, it is important to understand potential confounds and sources of variation in the process. While cross-scanner and cross-protocol effects on diffusion microstructure measures are well described (in particular fractional anisotropy and mean diffusivity), it is unknown how potential sources of variation effect bundle segmentation results, which features of the bundle are most affected, where variability occurs, nor how these sources of variation depend upon the method used to reconstruct and segment bundles. In this study, we investigate four potential sources of variation, or confounds, for bundle segmentation: variation (1) across scan repeats, (2) across scanners, (3) across acquisition protocol, and (4) across diffusion sensitization. We employ four different bundle segmentation workflows on two benchmark multi-subject cross-scanner and cross-protocol databases, and investigate reproducibility and biases in volume overlap, shape geometry features of fiber pathways, and microstructure features within the pathways. We find that the effects of acquisition protocol, in particular acquisition resolution, result in the lowest reproducibility of tractography and largest variation of features, followed by scanner-effects, and finally b-value effects which had similar reproducibility as scan-rescan variation. However, confounds varied both across pathways and across segmentation workflows, with some bundle segmentation workflows more (or less) robust to sources of variation. Despite variability, bundle dissection is consistently able to recover the same location of pathways in the deep white matter, with variation at the gray matter/ white matter interface. Next, we show that differences due to the choice of bundle segmentation workflows are larger than any other studied confound, with low-to-moderate overlap of the same intended pathway when segmented using different methods. Finally, quantifying microstructure features within a pathway, we show that tractography adds variability over-and-above that which exists due to noise, scanner effects, and acquisition effects. Overall, these confounds need to be considered when harmonizing diffusion datasets, interpreting or combining data across sites, and when attempting to understand the successes and limitations of different methodologies in the design and development of new tractography or bundle segmentation methods.

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