The field of stress physiology has rapidly expanded, particularly in those fields interested in identifying chronic stress in wild animals. Despite this expansion, stress remains difficult to assess ...and understand, due in large part to the temporal complexities of common stress measurement techniques.
While the stress response happens on a short time‐scale, chronic stress results over longer time‐scales. Therefore, the temporal dynamics of techniques used to assess ‘stress’ need to be fully understood in order to be applied correctly.
In this review, we provide information on 37 physiological and behavioural metrics that are commonly used to measure stress, especially in wild free‐living vertebrates, with a particular focus on which time‐scale they integrate stress.
We organize these metrics into seven broad categories based on which physiological system they are most closely associated with (glucocorticoids, sympathetic/parasympathetic nervous system, immune, metabolic, cellular/molecular, tissue development and behaviour).
We conclude by summarizing which kind of biological questions and variation each technique is most suitable for.
This review will enable researchers to understand the temporal dynamics of stress measurement techniques for better design of future studies.
A free Plain Language Summary can be found within the Supporting Information of this article.
A free Plain Language Summary can be found within the Supporting Information of this article.
Using the context of the 2021 U.S. Capitol riot, an attack on the U.S Congress that was in response to the alleged voter fraud perpetuated by high profile Republicans, this study sought to uncover ...the differences in content memory (i.e., free recall and recognition) scores for both factually correct and disinformation news content. In addition, it also explored how exposure to different message modalities (i.e., text, image, and video) may exacerbate the recall and recollection of news content, especially when presented with purposely misleading information. An online experiment (n = 568) using manipulated mock news articles was conducted to gauge participants' content memory for participants exposed to either factually correct or disinformation news content. Findings showcase that while there is no significant difference in content memory scores between those exposed to disinformation and factually correct news, partisans might be more tempted to purposely remember story details that support their party regardless of whether those details are accurate. Moreover, while modality may help in aiding one's memory for information, other factors such as expectancy-violation should be integrated with existing multimedia learning theories when applying the cognitive processing logic of modality to news consumption.
•Disinformation news content is recalled at a similar rate as content that is factually correct.•Partisans might be more tempted to communicate story details that support their party regardless if it is accurate.•Exposure to text and image articles generated greater recall when compared to video for non-disinformation news.•Exposure to the text article and video generated greater recall when compared to the image article for disinformation news.•Expectancy-violation may explain differentiating rates of recall across modalities and news types.
great human expansion Henn, Brenna M; Cavalli-Sforza, L. L; Feldman, Marcus W
Proceedings of the National Academy of Sciences,
10/2012, Letnik:
109, Številka:
44
Journal Article
Recenzirano
Odprti dostop
Genetic and paleoanthropological evidence is in accord that today’s human population is the result of a great demic (demographic and geographic) expansion that began approximately 45,000 to 60,000 y ...ago in Africa and rapidly resulted in human occupation of almost all of the Earth’s habitable regions. Genomic data from contemporary humans suggest that this expansion was accompanied by a continuous loss of genetic diversity, a result of what is called the “serial founder effect.” In addition to genomic data, the serial founder effect model is now supported by the genetics of human parasites, morphology, and linguistics. This particular population history gave rise to the two defining features of genetic variation in humans: genomes from the substructured populations of Africa retain an exceptional number of unique variants, and there is a dramatic reduction in genetic diversity within populations living outside of Africa. These two patterns are relevant for medical genetic studies mapping genotypes to phenotypes and for inferring the power of natural selection in human history. It should be appreciated that the initial expansion and subsequent serial founder effect were determined by demographic and sociocultural factors associated with hunter-gatherer populations. How do we reconcile this major demic expansion with the population stability that followed for thousands years until the inventions of agriculture? We review advances in understanding the genetic diversity within Africa and the great human expansion out of Africa and offer hypotheses that can help to establish a more synthetic view of modern human evolution.
Objective
Eating‐related fear and anxiety are hallmark symptoms of eating disorders (EDs). However, it is still unclear which fears are most important (e.g., food, weight gain), which has practical ...implications, given treatments for eating‐related fear necessitate modifications based on the specific fear driving ED pathology. For example, exposure treatments should be optimized based on specific fears that maintain pathology. The current study (N = 1,622 combined clinical ED and undergraduate sample) begins to answer questions on the precise nature of ED fears and how they operate with other ED symptoms.
Method
We used network analysis to create two models of ED fears and symptoms. The first model consisted of ED fears only (e.g., fears of food, fears of weight gain) to identify which fear is most central. The second model consisted of ED fears and ED symptoms to detect how ED fears operate with ED symptoms.
Results
We found fear of disliking how one's body feels due to weight gain, disliking eating in social situations, feeling tense around food, fear of judgment due to weight gain, and food anxiety were the most central ED fears. We also identified several bridge symptoms between ED fears and symptoms. Finally, we found that the most central ED fears predicted excessive exercise at two‐month follow‐up.
Discussion
These data support the idea that consequences (i.e., judgment) associated with fears of weight gain and interoceptive fears are the most central ED fears. These data have implications for the future development of precision interventions targeted to address ED‐related fear.
The human DARC (Duffy antigen receptor for chemokines) gene encodes a membrane-bound chemokine receptor crucial for the infection of red blood cells by Plasmodium vivax, a major causative agent of ...malaria. Of the three major allelic classes segregating in human populations, the FY*O allele has been shown to protect against P. vivax infection and is at near fixation in sub-Saharan Africa, while FY*B and FY*A are common in Europe and Asia, respectively. Due to the combination of strong geographic differentiation and association with malaria resistance, DARC is considered a canonical example of positive selection in humans. Despite this, details of the timing and mode of selection at DARC remain poorly understood. Here, we use sequencing data from over 1,000 individuals in twenty-one human populations, as well as ancient human genomes, to perform a fine-scale investigation of the evolutionary history of DARC. We estimate the time to most recent common ancestor (TMRCA) of the most common FY*O haplotype to be 42 kya (95% CI: 34-49 kya). We infer the FY*O null mutation swept to fixation in Africa from standing variation with very low initial frequency (0.1%) and a selection coefficient of 0.043 (95% CI:0.011-0.18), which is among the strongest estimated in the human genome. We estimate the TMRCA of the FY*A mutation in non-Africans to be 57 kya (95% CI: 48-65 kya) and infer that, prior to the sweep of FY*O, all three alleles were segregating in Africa, as highly diverged populations from Asia and ≠Khomani San hunter-gatherers share the same FY*A haplotypes. We test multiple models of admixture that may account for this observation and reject recent Asian or European admixture as the cause.
Statistical methods for identifying adaptive mutations from population genetic data face several obstacles: assessing the significance of genomic outliers, integrating correlated measures of ...selection into one analytic framework, and distinguishing adaptive variants from hitchhiking neutral variants. Here, we introduce SWIF(r), a probabilistic method that detects selective sweeps by learning the distributions of multiple selection statistics under different evolutionary scenarios and calculating the posterior probability of a sweep at each genomic site. SWIF(r) is trained using simulations from a user-specified demographic model and explicitly models the joint distributions of selection statistics, thereby increasing its power to both identify regions undergoing sweeps and localize adaptive mutations. Using array and exome data from 45 ‡Khomani San hunter-gatherers of southern Africa, we identify an enrichment of adaptive signals in genes associated with metabolism and obesity. SWIF(r) provides a transparent probabilistic framework for localizing beneficial mutations that is extensible to a variety of evolutionary scenarios.
We challenge the view that our species, Homo sapiens, evolved within a single population and/or region of Africa. The chronology and physical diversity of Pleistocene human fossils suggest that ...morphologically varied populations pertaining to the H. sapiens clade lived throughout Africa. Similarly, the African archaeological record demonstrates the polycentric origin and persistence of regionally distinct Pleistocene material culture in a variety of paleoecological settings. Genetic studies also indicate that present-day population structure within Africa extends to deep times, paralleling a paleoenvironmental record of shifting and fractured habitable zones. We argue that these fields support an emerging view of a highly structured African prehistory that should be considered in human evolutionary inferences, prompting new interpretations, questions, and interdisciplinary research directions.
The view that Homo sapiens evolved from a single region/population within Africa has been given primacy in studies of human evolution.
However, developments across multiple fields show that relevant data are no longer consistent with this view.
We argue instead that Homo sapiens evolved within a set of interlinked groups living across Africa, whose connectivity changed through time.
Genetic models therefore need to incorporate a more complex view of ancient migration and divergence in Africa.
We summarize this new framework emphasizing population structure, outline how this changes our understanding of human evolution, and identify new research directions.
To explore if short term, high dose vitamin D supplementation is safe and improves balance in persons with Parkinson's disease (PD).
A pilot randomized, double-blind intervention trial to measure the ...effects of 16 weeks of high dose vitamin D (10,000 IU/day) on balance as well as other motor and non-motor features of PD. We measured balance, gait, strength, falls, cognition, mood, PD severity, and quality of life before and after 16 weeks of high dose vitamin D supplementation or placebo. All participants also received 1000 mg calcium once daily.
Fifty-one randomized participants completed sixteen weeks of high dose vitamin D supplementation or placebo. The intervention resulted in a rise in serum concentrations of vitamin D (25-OH) (30.2 ng/ml to 61.1 ng/ml) and was well tolerated with no serious adverse events. Serum vitamin D (25-OH) levels rose steadily and did not suggest a leveling off at the end of the 16 weeks. There was not an improvement in the primary endpoint, balance as measured by the Sensory Organization Test (p = 0.43). A post hoc analysis examining treatment effects in younger (ages 52-66) versus older (ages 67-86) participants found a significant improvement in the SOT of 10.6 points in the younger half of the cohort (p = 0.012).
Short term, high dose vitamin D supplementation appears safe in persons with PD, but did not significantly improve balance as measured with the Sensory Organization Test in this pilot study population. A post hoc analysis suggests that vitamin D may have potential for improving balance in a younger population with PD. High dose vitamin D supplementation in PD needs further study especially in light of new research suggesting that mega doses and even moderate doses (as low as 4000IU a day) may increase falls in an older populations.
ClinicalTrials.gov: NCT01119131.
The Out-of-Africa (OOA) dispersal ∼50,000 y ago is characterized by a series of founder events as modern humans expanded into multiple continents. Population genetics theory predicts an increase of ...mutational load in populations undergoing serial founder effects during range expansions. To test this hypothesis, we have sequenced full genomes and high-coverage exomes from seven geographically divergent human populations from Namibia, Congo, Algeria, Pakistan, Cambodia, Siberia, and Mexico. We find that individual genomes vary modestly in the overall number of predicted deleterious alleles. We show via spatially explicit simulations that the observed distribution of deleterious allele frequencies is consistent with the OOA dispersal, particularly under a model where deleterious mutations are recessive. We conclude that there is a strong signal of purifying selection at conserved genomic positions within Africa, but that many predicted deleterious mutations have evolved as if they were neutral during the expansion out of Africa. Under a model where selection is inversely related to dominance, we show that OOA populations are likely to have a higher mutation load due to increased allele frequencies of nearly neutral variants that are recessive or partially recessive.
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