Frequency-modulated second elements of two-element alarm calls do not enhance discrimination of callers in three Eurasian ground squirrels

Alarm calls of the European Spermophilus citellus (EGS),Taurus S.taurensis (TGS) and Anatolian S.xanthoprymnus (AGS) ground squirrels share the same basic structure.They are tonal sounds consisting primarily of two different elements.The first element,often produced without the second element,has limited frequency modulation,while the second element is more frequency modulated.The present study examined whether this frequency-modulated element enhances the individual distinctiveness of calls,allowing calls to be ascribed with greater confidence to individual callers of the three species.Cross-validated discriminant function analysis (DFA) based on five acoustic parameters of the first element successfully classified calls to correct individuals (EGS:90％,TGS:98％,AGS:96％).Cross-validated DFA based on five acoustic parameters of the second element was also successful in classifications (EGS:88％,TGS:86％,AGS:96％),though discrimination of callers based on parameters of the second versus first element was the same for the AGS,lower for the EGS and significantly lower for the TGS.Cross-validated DFA based on five acoustic parameters of two-element calls also successfully classified calls to correct individuals (EGS:93％,TGS:98％,AGS:97％),though did not improve the extent to which calls could be classified to individuals beyond that based on the first element alone.Thus,the second element does not enhance the individual distinctiveness of calls,but may convey other information such as the location of the caller.     

Giant otter alarm calls as potential mechanisms for individual discrimination and sexual selection

Acoustic variation can convey identity information, facilitate social interactions among individuals and may be useful in identifying sex and group affiliation of senders. Giant otters live in highly cohesive groups with exclusive territories along water bodies defended by the entire group by means of acoustic and chemical signals. Snorts are harsh alarm calls, emitted in threat contexts, which commonly elicit the cohesion and the alert behaviour of the members of the group. The aim of this study was to determine whether giant otter snorts have potential to be used for individual discrimination. We tested this hypothesis by verifying if the acoustic characteristics of snorts vary between two study areas, among social groups and individuals, and between males and females. Snort acoustic variables did not differ significantly among study areas, but varied significantly among groups, individuals and between sexes, with higher discrimination between sexes. The frequency of formants (F1–F5) and formant dispersion (DF) potentially allow identity coding among groups, individuals and sexes. The stronger sex discrimination of snorts may be related to information on body size carried by formant frequencies and dispersion, indicating acoustic sexual dimorphism in giant otters. Acoustic differences among groups and individuals are more likely learned, since we did not find evidence for a genetic signal encoded in the snort variables measured. We conclude that the snorts carry information that could be used for individual or group recognition.     

Niche construction,adaptive preferences,and the differences between fitness and utility

A number of scholars have recently defended the claim that there is a close connection between the evolutionary biological notion of fitness and the economic notion of utility: both are said to refer to an organism’s success in dealing with its environment, and both are said to play the same theoretical roles in their respective sciences. However, an analysis of two seemingly disparate but in fact structurally related phenomena—‘niche construction’ (the case where organisms change their environment to make it fit to their needs) and ‘adaptive preferences’ (the case where agents change their wants to make them fit to what the world has given them)—shows that one needs to be very careful about the postulation of this sort of fitness–utility connection. Specifically, I here use the analysis of these two phenomena to establish when connecting fitness and utility is and is not possible.     

Tetrapeptide substrates for the discrimination among kallikreins and other trypsin-like serine proteinases

The three tetrapeptides Ac-Phe-Arg-Arg-Val-NH2 (I), Ac-Phe-Arg-Arg-Pro-NH2 (II) and Ac-Phe-Lys-Arg-Val-NH2 (III) were shown to form a most convenient substrate system for the discrimination of the serine proteinases listed below. Tissue kallikreins (porcine pancreatic, horse and human urinary) have the unique feature of cleaving well the Arg-Arg bond in peptide I (P'2 = Val), hardly splitting it in peptide II (P'2 = Pro). The kcat/Km for the hydrolysis of peptide II by horse urinary kallikrein was 600-fold lower than that for peptide I. Trypsin, plasma kallikreins (human and rat), tonin and rat urinary kallikrein were distinguished from each other by the sequence of the N-terminal fragments formed in the hydrolysis of peptides I and/or II. Differences in the cleavage sites in these peptides are explained by differences in the specificities of the proteinase subsite S2 and/or in their preference for Arg or Lys residues. The three tetrapeptides were not substrates for plasmin.     

Racial and ethnic differences in perceptions of discrimination among Muslim Americans

I use data from the 2011 Pew Survey (N?=?1,033) to examine the prevalence and correlates of perceived discrimination across Muslim American racial/ethnic groups. Asian Muslims report the lowest frequency of perceived discrimination than other Muslim racial/ethnic groups. Nearly, all Muslim racial/ethnic groups have a few times higher odds of reporting one or more types of perceived discrimination than white Muslims. After controlling for socio-demographic characteristics, the observed relationships persist for Hispanic Muslims but disappear for black and other/mixed race Muslims. Women are less likely than men to report several forms of discrimination. Older Muslims report lower rates of perceived discrimination than younger Muslims. White Muslim men are more likely to report experiencing discrimination than white, black and Asian Muslim women. The findings highlight varying degrees of perceived discrimination among Muslim American racial/ethnic groups and suggest examining negative implications for Muslims who are at the greatest risk of mistreatment.     

Geophagy among primates: adaptive significance and ecological consequences

We review geophagy, or soil ingestion, in primates. This behaviour is widespread and is presumed to be important to health and nutrition. Primates may engage in geophagy for one or a combination of reasons. Here we present, and make a preliminary assessment of, six nonexclusive hypotheses that may contribute to the prevalence of geophagy. Four hypotheses relate to geophagy in alleviating gastrointestinal disorders or upsets: (1) soils adsorb toxins such as phenolics and secondary metabolites; (2) soil ingestion has an antacid action and adjusts the gut pH; (3) soils act as an antidiarrhoeal agent; and (4) soils counteract the effects of endoparasites. Two hypotheses pertain to geophagy in supplementing minerals and/or elements: (5) soils supplement nutrient-poor diets and (6) soils provide extra iron at high altitudes. In addition to these hypotheses, geophagy may satiate olfactory senses, serve as a famine food and finally may have no function at all. We draw together a large body of information from various sources to assess these hypotheses and suggest some tests to understand the function of geophagy. Our review suggests that primates engage in geophagy for a number of reasons that are nonexclusive. We conclude that mineral supplementation, adsorption of toxins, treatment of diarrhoea and pH adjustment of the gut seem the most plausible reasons why primates engage in geophagy. Copyright 2000 The Association for the Study of Animal Behaviour.     

From nestling calls to fledgling silence: adaptive timing of change in response to aerial alarm calls

Young birds and mammals are extremely vulnerable to predators and so should benefit from responding to parental alarm calls warning of danger. However, young often respond differently from adults. This difference may reflect: (i) an imperfect stage in the gradual development of adult behaviour or (ii) an adaptation to different vulnerability. Altricial birds provide an excellent model to test for adaptive changes with age in response to alarm calls, because fledglings are vulnerable to a different range of predators than nestlings. For example, a flying hawk is irrelevant to a nestling in a enclosed nest, but is dangerous to that individual once it has left the nest, so we predict that young develop a response to aerial alarm calls to coincide with fledging. Supporting our prediction, recently fledged white-browed scrubwrens, Sericornis frontalis, fell silent immediately after playback of their parents' aerial alarm call, whereas nestlings continued to calling despite hearing the playback. Young scrubwrens are therefore exquisitely adapted to the changing risks faced during development.     

Reliability of two-point discrimination thresholds using a 4-2-1 stepping algorithm

Purpose: A 4-2-1 stepping algorithm reliably captures light touch thresholds but has not been used to assess two-point discrimination (TPD) thresholds. Therefore, the purpose of this investigation was to determine the intra- and inter-rater reliability of a 4-2-1 stepping algorithm at determining TPD thresholds.

Materials and methods: Fifteen healthy, physically active young adults were assessed twice over a 1-week period using digital calipers and a 4-2-1 stepping algorithm. TPD thresholds were assessed by an expert and a novice examiner at each time point. Reliability was assessed on the plantar surface of the foot at the head of the first and base of the fifth metatarsal.

Results: Three intra-rater intraclass correlation coefficient (ICC) values exceeded 0.75 and were interpreted as good. The inter-rater reliability was good with ICC values ranging from 0.76 to 0.93 at both sites during both test sessions.

Conclusions: The 4-2-1 stepping algorithm demonstrates good intra- and inter-tester reliability at determining TPD thresholds on the plantar surface of the foot at the head of the first and base of the fifth metatarsal in young healthy adults.     

Alternate indices of electric and magnetic field exposures among Ontario electrical utility workers

Epidemiologic studies examining the risk of cancer among occupational groups exposed to electric fields (EF) and or magnetic fields (MF) have relied on traditional summaries of exposure such as the time weighted arithmetic or geometric mean exposure. Findings from animal and cellular studies support the consideration of alternative measures of exposure capable of capturing threshold and intermittent measures of field strength. The main objective of this study was to identify a series of suitable exposure metrics for an ongoing cancer incidence study in a cohort of Ontario electric utility workers. Principal components analysis (PCA) and correlational analysis were used to explore the relationships within and between series of EF and MF exposure indices. Exposure data were collected using personal monitors worn by a sample of 820 workers which yielded 4247 worker days of measurement data. For both EF and MF, the first axis of the PCA identified a series of intercorrelated indices that included the geometric mean, median and arithmetic mean. A considerable portion of the variability in EF and MF exposures were accounted for by two other principal component axes. The second axes for EF and MF exposures were representative of the standard deviation (standard deviation) and thresholds of field measures. To a lesser extent, the variability in the exposure variable was explained by time dependent indices which consisted of autocorrelations at 5 min lags and average transitions in field strength. Our results suggest that the variability in exposure data can only be accounted for by using several exposure indices, and consequently, a series of metrics should be used when exploring the risk of cancer owing to MF and EF exposure in this cohort. Furthermore, the poor correlations observed between indices of MF and EF reinforce the need to be take both fields into account when assessing the risk of cancer in this occupational group. Bioelectromagnetics 19:140–151, 1998. © 1998 Wiley-Liss, Inc.     

Correlations among indices of electric and magnetic field exposure in electric utility workers

Power-frequency electric and magnetic fields are known to exhibit marked temporal variation, yet in the absence of clear biological indications, the most appropriate summary indices for use in epidemiologic studies are unknown. In order to assess the statistical patterns among candidate indices, data on 4383 worker-days for magnetic fields and 2082 worker-days for electric fields collected for the Electric and Magnetic Field Project for Electric Utilities using the EMDEX meter [Bracken (1990): Palo Alto, CA: Electric Power Research Institute] were analyzed. We examined correlations at the individual and job title group levels among indices of exposure to both electric and magnetic fields, including the arithmetic mean, geometric mean, median, 20th and 90th percentiles, time above lower cutoffs of 20 V/m and 0.2 μT, and time above higher cutoffs of 100 V/m and 2.0 μT. For both electric and magnetic fields, the arithmetic mean was highly correlated with the 90th percentile; moderately correlated with the geometric mean, median, and lower and higher cutoff scores; and weakly correlated with the 20th percentile. Electric and magnetic field indices were generally weakly correlated with one another. Rank-order correlation coefficients were consistently greater than product-moment correlation coefficients. Job title group summary scores showed higher correlations among electric field indices and magnetic field indices and between electric and magnetic field indices than was found for individual worker-days, with only the 20th percentile clearly independent of the others. These results suggest that individuals' exposures are adequately characterized by a measure of central tendency for electric and magnetic fields, such as the arithmetic or geometric mean, and an indicator of a lower threshold or cutoff for each field type, such as the 20th percentile or proportion of time above 20 V/m or 0.2 μT. A single measure of central tendency for each type of field appears to be adequate when exposures are assessed at the job title level. © 1994 Wiley-Liss, Inc.     

Variation in the degree and costs of adaptive phenotypic plasticity among Rana temporaria populations

Adaptive phenotypic plasticity in the form of capacity to accelerate development as a response to pond drying risk is known from many amphibian species. However, very little is known about factors that might constrain the evolution of this type of plasticity, and few studies have explored to what degree plasticity might be constrained by trade-offs dictated by adaptation to different environmental conditions. We compared the ability of southern and northern Scandinavian common frog (Rana temporaria) larvae originating from 10 different populations to accelerate their development in response to simulated pond drying risk and the resulting costs in metamorphic size in a factorial laboratory experiment. We found that (i) northern larvae developed faster than the southern larvae in all treatments, (ii) a capacity to accelerate the response was present in all five southern and all five northern populations tested, but that the magnitude of the response was much larger (and less variable) in the southern than in the northern populations, and that (iii) significant plasticity costs in metamorphic size were present in the southern populations, the plastic genotypes having smaller metamorphic size in the absence of desiccation risk, but no evidence for plasticity costs was found in the northern populations. We suggest that the weaker response to pond drying risk in the northern populations is due to stronger selection on large metamorphic size as compared with southern populations. In other words, seasonal time constraints that have selected the northern larvae to be fast growing and developing, may also constrain their innate ability for adaptive phenotypic plasticity.     

Perceived discrimination and diurnal cortisol: examining relations among Mexican American adolescents

Perceived discrimination remains a salient and significant environmental stressor for ethnic and racial minority youth. Although many studies have examined the impact of racial/ethnic discrimination on mental health symptomatology and physical health, little is known of the potential physiological processes underlying such experiences, especially during adolescence. In an attempt to understand how varying perceptions of discrimination relate to functioning of the hypothalamic-pituitary-adrenal axis (HPA axis), the current study examined the relation between Mexican American adolescents' (N = 100, M(age) = 15.3 years old) perceptions of discrimination and aspects of their diurnal cortisol profiles. Three salivary samples (wakeup, +30 waking, bedtime) were collected across 3 days (total of 9 samples). Utilizing multi-level modeling, results revealed that adolescents' perceived discrimination related to greater overall cortisol output (area under the curve; AUC) after controlling for other life stressors, depressive symptoms, family income, acculturation level, daily stress levels and daily behaviors. Findings also revealed that perceived discrimination was marginally related to a steeper cortisol awakening response (CAR). Together, these findings suggest that perceived discrimination is a salient and impactful stressor for Mexican American adolescents. Understanding the physiological correlates of discrimination can provide insight into larger health disparities among ethnic and racial minority individuals.     

Dietary change and adaptive evolution of enamelin in humans and among primates

Scans of the human genome have identified many loci as potential targets of recent selection, but exploration of these candidates is required to verify the accuracy of genomewide scans and clarify the importance of adaptive evolution in recent human history. We present analyses of one such candidate, enamelin, whose protein product operates in tooth enamel formation in 100 individuals from 10 populations. Evidence of a recent selective sweep at this locus confirms the signal of selection found by genomewide scans. Patterns of polymorphism in enamelin correspond with population-level differences in tooth enamel thickness, and selection on enamel thickness may drive adaptive enamelin evolution in human populations. We characterize a high-frequency nonsynonymous derived allele in non-African populations. The polymorphism occurs in codon 648, resulting in a nonconservative change from threonine to isoleucine, suggesting that the allele may affect enamelin function. Sequences of exons from 12 primate species show evidence of positive selection on enamelin. In primates, it has been documented that enamel thickness correlates with diet. Our work shows that bursts of adaptive enamelin evolution occur on primate lineages with inferred dietary changes. We hypothesize that among primate species the evolved differences in tooth enamel thickness are correlated with the adaptive evolution of enamelin.     

Song discrimination suggests premating isolation among sympatric indigobird species and host races

Indigobirds (Vidua spp.) are host-specific brood parasites thathave diversified in a recent radiation apparently driven byhost colonization. Behavioral imprinting of both male and femaleindigobirds on host song is thought to promote rapid speciationbecause it results in assortative mating between indigobirdsassociated with a particular host. We conducted a song playbackexperiment to test whether male indigobirds discriminate amongpotential competitors based on song. Of particular interestwas the behavior of two sympatric host races of the Cameroonindigobird Vidua camerunensis that differ only in host songmimicry and other components of their vocal repertoires. Territorialmales of the two V. camerunensis host races and Vidua raricola,a morphologically distinct indigobird species, were tested withplaybacks of each other's songs. Males of all three groups respondedmost aggressively to songs of their own species and/or hostrace, as evidenced by strong and highly significant differencesin a variety of response variables. This differential territorialdefense suggests that an intruding male with different songsdoes not represent a competitive threat and is expected if femalesmate assortatively with respect to song. Thus, our results provideevidence of premating reproductive isolation among recentlyevolved indigobird species and host races.     

Testing the Validity and Reliability of the Shame Questionnaire among Sexually Abused Girls in Zambia

Purpose

The aim of the current study is to test the validity and reliability of the Shame Questionnaire among traumatized girls in Lusaka, Zambia.

Methods

The Shame Questionnaire was validated through both classical test and item response theory methods. Internal reliability, criterion validity and construct validity were examined among a sample of 325 female children living in Zambia. Sub-analyses were conducted to examine differences in construct validity among girls who reported sexual abuse and girls who did not.

Results

All girls in the sample were sexually abused, but only 61.5% endorsed or reported that sexual abuse had occurred. Internal consistency was very good among the sample with alpha = .87. Criterion validity was demonstrated through a significant difference of mean Shame Questionnaire scores between girls who experienced 0–1 trauma events and more than one traumatic event, with higher mean Shame Questionnaire scores among girls who had more than one traumatic event (p = .004 for 0–1 compared to 2 and 3 events and p = .016 for 0–1 compared to 4+ events). Girls who reported a history of witnessing or experiencing physical abuse had a significantly higher mean Shame Questionnaire score than girls who did not report a history of witnessing or experiencing physical abuse (p<.0001). There was no significant difference in mean Shame Questionnaire score between girls who reported a sexual abuse history and girls who did not. Exploratory factor analysis indicated a two-factor model of the Shame Questionnaire, with an experience of shame dimension and an active outcomes of shame dimension. Item response theory analysis indicated adequate overall item fit. Results also indicate potential differences in construct validity between girls who did and did not endorse sexual abuse.

Conclusions

This study suggests the general utility of the Shame Questionnaire among Zambian girls and demonstrates the need for more psychometric studies in low and middle income countries.