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1.
Artículo en Inglés | MEDLINE | ID: mdl-35627337

RESUMEN

Hypertension is one of the crucial risk factors for morbidity and mortality around the world, and South Africa has a significant unmet need for hypertension care. This study aims to establish the potential risk factors of hypertension amongst adults in South Africa attributable to high systolic and diastolic blood pressure over time by fitting panel quantile regression models. Data obtained from the South African National Income Dynamics Study (NIDS) Household Surveys carried out from 2008 to 2018 (Wave 1 to Wave 5) was employed to develop both the fixed effects and random effects panel quantile regression models. Age, BMI, gender (males), race, exercises, cigarette consumption, and employment status were significantly associated with either one of the BP measures across all the upper quantiles or at the 75th quantile only. Suggesting that these risk factors have contributed to the exacerbation of uncontrolled hypertension prevalence over time in South Africa.


Asunto(s)
Hipertensión , Adulto , Población Negra , Presión Sanguínea/fisiología , Humanos , Hipertensión/epidemiología , Masculino , Factores de Riesgo , Sudáfrica/epidemiología
2.
Inquiry ; 59: 469580221082356, 2022.
Artículo en Inglés | MEDLINE | ID: mdl-35373630

RESUMEN

Hypertension has become a major public health challenge and a crucial area of research due to its high prevalence across the world including the sub-Saharan Africa. No previous study in South Africa has investigated the impact of blood pressure risk factors on different specific conditional quantile functions of systolic and diastolic blood pressure using Bayesian quantile regression. Therefore, this study presents a comparative analysis of the classical and Bayesian inference techniques to quantile regression. Both classical and Bayesian inference techniques were demonstrated on a sample of secondary data obtained from South African National Income Dynamics Study (2017-2018). Age, BMI, gender male, cigarette consumption and exercises presented statistically significant associations with both SBP and DBP across all the upper quantiles (τ∈{0.75,0.95}). The white noise phenomenon was observed on the diagnostic tests of convergence used in the study. Results suggested that the Bayesian approach to quantile regression reveals more precise estimates than the frequentist approach due to narrower width of the 95% credible intervals than the width of the 95% confidence intervals. It is therefore suggested that Bayesian approach to quantile regression modelling to be used to estimate hypertension.


Asunto(s)
Hipertensión , Teorema de Bayes , Presión Sanguínea/fisiología , Ejercicio Físico , Humanos , Hipertensión/epidemiología , Masculino , Sudáfrica/epidemiología
3.
Evolution ; 76(4): 799-816, 2022 04.
Artículo en Inglés | MEDLINE | ID: mdl-35238032

RESUMEN

Little is known about the intraspecific variation of parasite life-history traits and how this variation may affect parasite fitness and evolution. We investigated how life-history traits predict success of individual tree-hole ticks Ixodes arboricola and estimated their evolutionary potential, as well as genetic correlations within stages and phenotypic correlations within and across stages. Ticks were followed individually over two generations while allowed to feed on great tits Parus major. After accounting for host and tick maternal effects, we found that short feeding times and high engorgement weights strongly increased molting success. Molting time was also positively correlated with feeding success in adults. In larvae and nymphs, we found negative phenotypic correlations between engorgement weight and both feeding and molting time, the latter supported by a negative genetic correlation. We found sex-related differences in feeding time (longer in male nymphs) and molting time (longer in male larvae but shorter in male nymphs). Also, time since the last feeding event (set experimentally) reduced larval and nymphal fitness, whereas it increased adult female fitness. Furthermore, we found significant heritability and evolvability, that is, the potential to respond to selection, for engorgement weight and molting time across all stages but no significant heritability for feeding time. Our findings suggest that variation in tick fitness is shaped by consistent individual differences in tick quality, for which engorgement weight is a good proxy, rather than by life-history trade-offs.


Asunto(s)
Ixodes , Rasgos de la Historia de Vida , Passeriformes , Animales , Conducta Alimentaria , Femenino , Larva , Masculino , Ninfa/genética
4.
Front Psychol ; 13: 1051143, 2022.
Artículo en Inglés | MEDLINE | ID: mdl-36591010

RESUMEN

Social support has been shown to be a crucial element in the well-being of children and adolescents. The present research article investigated how various sources of social support (i.e., parental support, teacher support and peer support) are related to school well-being and general well-being,. A survey was administered to N = 12,215 primary school pupils, pertaining to three ethnic-cultural groups, i.e., the national majority group, the Eastern European minority group and the Middle Eastern minority group. The results showed that perceived teacher support was most strongly and positively related to school well-being, although peer support was also an important determinant of school well-being. All three sources of perceived support were positively related to general well-being. Furthermore, and contrary to previous research, no significant differences were found between both minority groups and the national majority in terms of perceived teacher support. Conversely, both minority groups reported lower perceived parental and peer support. It was further shown that minority status moderated the relationship between the various sources of support and school well-being, although it should be articulated that these effects sizes were fairly small. School diversity, finally, did not yield any relevant effects. Similarities and differences with the existing literature on school well-being are delineated, and potential explanations for these divergences are discussed.

5.
Insects ; 12(8)2021 Aug 17.
Artículo en Inglés | MEDLINE | ID: mdl-34442300

RESUMEN

Nocturnal light pollution from anthropogenic origin is increasing worldwide and is recognised as a major threat for nocturnal biodiversity. We studied the impact of artificial light on the mate attraction success of female common glow-worms (Lampyris noctiluca L.) by daily monitoring their glowing status in the field, acting as a proxy for mating status throughout the mating season. We found that females in dark surroundings typically stopped glowing after one night, indicating that they had mated, while females in illuminated areas glowed for significantly more nights, in some cases up to 15 nights. Our study confirms previous findings and hypotheses that females exposed to artificial light suffer from a reduced mate attraction success with a negative impact on populations.

6.
Symmetry (Basel) ; 13(2)2021 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-33664983

RESUMEN

BACKGROUND: Fluctuating asymmetry is often used as an indicator of developmental instability, and is proposed as a signal of genetic quality. The display of prominent masculine phenotypic features, which are a direct result of high androgen levels, is also believed to be a sign of genetic quality, as these hormones may act as immunosuppressants. Fluctuating asymmetry and masculinity are therefore expected to covary. However, there is lack of strong evidence in the literature regarding this hypothesis. MATERIALS AND METHODS: In this study, we examined a large dataset of high-density 3D facial scans of 1260 adults (630 males and 630 females). We mapped a high-density 3D facial mask onto the facial scans in order to obtain a high number of quasi-landmarks on the faces. Multi-dimensional measures of fluctuating asymmetry were extracted from the landmarks using Principal Component Analysis, and masculinity/femininity scores were obtained for each face using Partial Least Squares. The possible correlation between these two qualities was then examined using Pearson's coefficient and Canonical Correlation Analysis. RESULTS: We found no correlation between fluctuating asymmetry and masculinity in men. However, a weak but significant correlation was found between average fluctuating asymmetry and masculinity in women, in which feminine faces had higher levels of fluctuating asymmetry on average. This correlation could possibly point to genetic quality as an underlying mechanism for both asymmetry and masculinity; however, it might also be driven by other fitness or life history traits, such as fertility. CONCLUSIONS: Our results question the idea that fluctuating asymmetry and masculinity should be (more strongly) correlated in men, which is in line with the recent literature. Future studies should possibly focus more on the evolutionary relevance of the observed correlation in women.

7.
BMC Fam Pract ; 22(1): 52, 2021 03 11.
Artículo en Inglés | MEDLINE | ID: mdl-33706721

RESUMEN

BACKGROUND: In western Kenya, women often present with late-stage cervical cancer despite prior contact with the health care system. The aim of this study was to predict primary health care providers' behaviour in examining women who present with abnormal discharge or bleeding. METHODS: This was a cross-sectional survey using the theory of planned behaviour (TPB). A sample of primary health care practitioners in western Kenya completed a 59-item questionnaire. Structural equation modelling was used to identify the determinants of providers' intention to perform a gynaecological examination. Bivariate analysis was conducted to investigate the relationship between the external variables and intention. RESULTS: Direct measures of subjective norms (DMSN), direct measures of perceived behavioural control (DMPBC), and indirect measures of attitude predicted the intention to examine patients. Negative attitudes toward examining women had a suppressor effect on the prediction of health workers' intentions. However, the predictors of intention with the highest coefficients were the external variables being a nurse (ß = 0.32) as opposed to a clinical officer and workload of attending less than 50 patients per day (ß = 0.56). In bivariate analysis with intention to perform a gynaecological examination, there was no evidence that working experience, being female, having a lower workload, or being a private practitioner were associated with a higher intention to conduct vaginal examinations. Clinical officers and nurses were equally likely to examine women. CONCLUSIONS: The TPB is a suitable theoretical basis to predict the intention to perform a gynaecological examination. Overall, the model predicted 47% of the variation in health care providers' intention to examine women who present with recurrent vaginal bleeding or discharge. Direct subjective norms (health provider's conformity with what their colleagues do or expect them to do), PBC (providers need to feel competent and confident in performing examinations in women), and negative attitudes toward conducting vaginal examination accounted for the most variance. External variables in this study also contributed to the overall variance. As the model in this study could not explain 53% of the variance, investigating other external variables that influence the intention to examine women should be undertaken.


Asunto(s)
Detección Precoz del Cáncer , Personal de Salud/psicología , Neoplasias del Cuello Uterino/diagnóstico , Excreción Vaginal/etiología , Adulto , Anciano , Estudios Transversales , Femenino , Examen Ginecologíco , Humanos , Intención , Kenia , Masculino , Persona de Mediana Edad , Encuestas y Cuestionarios , Neoplasias del Cuello Uterino/etnología
8.
Anat Rec (Hoboken) ; 304(12): 2673-2684, 2021 12.
Artículo en Inglés | MEDLINE | ID: mdl-33773061

RESUMEN

In a recent article in this journal, Galeta et al., (2020) discussed eight Pleistocene "protodogs" and seven Pleistocene wolves. Those "protodogs" had been diagnosed in earlier publications, based on skull morphology. We re-examined the Galeta et al. paper to offer comments on their observed outcomes, and the conclusion of presumed domestication. Of seven metrics that the authors used, five differed statistically between their two groups. However, from more elaborate studies, some of those same metrics had been rejected previously as not valid species-distinguishing traits. In this respect, we do accept cranium size and wider palate as species-distinguishing metrics. The physical size of their specimens was much larger than other archaeological specimens that have been accepted as dogs. Additionally, their sample size was small, compared to the number of available specimens, as shown from previous publications by the same group. Thus, we considered statistical differences that were found between groups in their study, and assessed whether the outcomes could have resulted from natural morphological variation. We examined a group of 73 dire wolves ((Aenocyon [Canis] dirus; Perri et al., 2021), using the same methods as used by Galeta et al., (2020). We could segregate two distinct morphological groups in our study, one having outcomes that were identical to the "protodogs" in Galeta et al. (2020). For the specimens of extinct dire wolves to segregate in the same way as the subjects from Galeta et al. indicates that natural variation probably was the driver of their observed outcomes, domestication being an unlikely assumption.


Asunto(s)
Arqueología , Perros , Animales
9.
Adapt Human Behav Physiol ; 7(1): 73-88, 2021 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-33575162

RESUMEN

Studies suggest that high levels of masculinity in men can be a signal of 'better genes' as well as low parental investment. It is the trade-off between these two qualities that has led to the hypothesis that women's preferences for male masculinity are condition-dependent, yet, not all studies support this hypothesis. In addition, there is evidence that more average faces would be perceived as more attractive. Here we study the variation in masculinity preferences of a cohort of heterosexual women (n=769), using manipulated 3D faces of male subjects. We used linear mixed models to test for effects of various covariates such as relationship status, use of hormonal contraception, sociosexual orientation and self-perceived attractiveness on preference for masculinity. Our results show that women's sociosexual orientation has a positive correlation with masculinity preference while using hormonal contraception decreases this preference. None of the other covariates displayed any significant effect on masculinity preference. The initial level of masculinity of the faces (very low, low, average, high and very high) was also shown to affect this preference, where we found a significant preference for higher masculinity in the very low and average group, while no preference was found in the other groups. Our findings support the notion that condition-dependent variables have very small effects, if any, on women's preference for masculinity in men.

10.
Vet Surg ; 49(7): 1449-1457, 2020 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-32706139

RESUMEN

OBJECTIVE: To determine whether using 12.5° Slocum-like triple pelvic osteotomy (TPO) plates would create sufficient femoral head coverage and lower the occurrence of overrotation compared with using 20° TPO plates in dogs with hip dysplasia. STUDY DESIGN: Prospective clinical study. SAMPLE POPULATION: Thirty-five dogs with hip dysplasia (38 hips). METHODS: Nineteen hips were surgically treated with a custom-made Slocum-type 12.5° TPO plate, and these were matched to 19 hips surgically treated with a 20° commercial Slocum TPO plate. Hips were case matched according to size and breed. Ortolani sign, angles of subluxation and reduction, distraction index, and femoral head coverage (FHC) were compared between groups. Excessive coverage was defined as >80%. RESULTS: In the 12.5° group, FHC was ≥50% in all hips, with mean FHC (67%), gain (37%), and excessive coverage (11%) all significantly less than in the 20° group (79%, 54%, and 42%, respectively). CONCLUSION: The 12.5° plate produced sufficient FHC compared with the 20° plate, with fewer hips with excessive coverage. CLINICAL SIGNIFICANCE: The 12.5° TPO plate may result in sufficient FHC with a lower occurrence of excessive coverage compared with 20° plates.


Asunto(s)
Artroplastia de Reemplazo de Cadera/veterinaria , Placas Óseas/veterinaria , Displasia Pélvica Canina/cirugía , Osteotomía/veterinaria , Pelvis/cirugía , Animales , Perros , Femenino , Masculino , Proyectos Piloto
11.
J Anim Ecol ; 89(7): 1559-1569, 2020 07.
Artículo en Inglés | MEDLINE | ID: mdl-32291765

RESUMEN

Understanding the effects of invasive alien species (IAS) on native host-parasite relationships is of importance for enhancing ecological theory and IAS management. When IAS and their parasite(s) invade a guild, the effects of interspecific resource competition and/or parasite-mediated competition can alter existing native host-parasite relationships and the dependent biological traits such as native species' behaviour. We used a natural experiment of populations of native red squirrels Sciurus vulgaris that were colonized by the alien grey squirrel Sciurus carolinensis, comparing repeated measurements of red squirrel parasite infection and personality with those taken in sites where only the native species occurred. We explored two alternative hypotheses: (a) individual differences in personality traits (activity and/or sociability) of native red squirrel positively affect the probability of macroparasite spillover and thus the likelihood to acquire the alien's parasitic helminth Strongyloides robustus; (b) the combined effects of grey squirrel presence and parasite infection result in a reduction of costly personality traits (activity and/or exploration). Using data from 323 arena tests across three experimental (native species and IAS) and three control sites (only native species), we found negative correlations between native species' activity and infection with S. robustus in the sites invaded by the alien species. Activity was also negatively correlated with infection by its native helminth Trypanoxyuris sciuri but only when grey squirrels were present, while in the red-only sites there was no relationship of T. sciuri infection with any of the personality traits. Moreover, individuals that acquired S. robustus during the study reduced their activity after infection, while this was not the case for animals that remained uninfected. Our results show that parasite-mediated competition is costly, reducing activity in individuals of the native species, and altering the native host-native parasite relationships.


Asunto(s)
Helmintos , Parásitos , Animales , Especificidad del Huésped , Especies Introducidas , Sciuridae
12.
Evol Hum Sci ; 2: e35, 2020.
Artículo en Inglés | MEDLINE | ID: mdl-37588384

RESUMEN

Facial fluctuating asymmetry (FA), presumably a proxy measure of developmental instability, has been proposed to inversely relate to vocal attractiveness, which may convey information on heritable fitness benefits. Using an improved method of measuring facial FA, we sought to replicate two recent studies that showed an inverse correlation of facial FA with vocal attractiveness. In two samples of men (N = 165) and women (N = 157), we investigated the association of automatically measured facial FA based on 3D face scans with male and female observer-rated attractiveness of voice recordings. No significant associations were found for men or women, also when controlling for facial attractiveness, age, and body mass index. Equivalence tests show that effect sizes were significantly smaller than previous meta-analytic effects, providing robust evidence against a link of facial FA with vocal attractiveness. Thus, our study contradicts earlier findings that vocal attractiveness may signal genetic quality in humans via an association with FA.

13.
PLoS Negl Trop Dis ; 13(8): e0007667, 2019 08.
Artículo en Inglés | MEDLINE | ID: mdl-31425506

RESUMEN

BACKGROUND: Ochollo is a village in southern Ethiopia burdened with cutaneous leishmaniasis (CL), where Phlebotomus pedifer is the only vector for Leishmania aethiopica and hyraxes are confirmed reservoir hosts. A detailed description of the different players of transmission, and the ecology and seasonality of the vector needs to be established in order to accomplish efficient control programs. METHODS AND FINDINGS: Between March 2017 and February 2018, a monthly sandfly collection was carried out in different habitats and records of temperature and humidity were taken. Rodents and hyraxes were trapped in the dry and wet season. All samples were screened for Leishmania kinetoplast DNA (kDNA). Positive samples were further processed for determination of the Leishmania species and the species of the sandfly/small mammal that was found infected. Additionally, the species of 400 sandfly specimens from different habitats and seasons was identified. 17,190 Sergentomyia and Phlebotomus sandflies were caught and showed an overall kDNA prevalence of 2.6%, all were L. aethiopica infections only found in P. pedifer. The overall sandfly and P. pedifer abundance peaked in the dry season and was negatively correlated with the %RH. The kDNA prevalence varied over the months and was negatively correlated with the temperature. Total sandfly abundance did not differ between the sampled habitats, but P. pedifer was the distinct predominant species only in caves. Moreover, significantly more infected sandflies were found in caves. Only 1/192 rodents were kDNA positive, while 20.0% (5/25) of Heterohyrax brucei were found infected. CONCLUSIONS: This study suggests that caves may be a source of multiplication of the infection. If an outdoor control program would be considered, it would be useful to focus on caves in the wet season, when the sandfly abundance is lowest. The captured rodent species appear not important for transmission and the contribution of hyraxes in transmission should be further investigated.


Asunto(s)
ADN Protozoario/análisis , Reservorios de Enfermedades , Vectores de Enfermedades , Damanes/parasitología , Leishmania/genética , Leishmaniasis Cutánea/epidemiología , Psychodidae/parasitología , Animales , ADN Protozoario/genética , Transmisión de Enfermedad Infecciosa , Etiopía/epidemiología , Femenino , Humanos , Humedad , Leishmaniasis Cutánea/transmisión , Masculino , Carga de Parásitos , Prevalencia , Psychodidae/crecimiento & desarrollo , Estaciones del Año , Temperatura
14.
Sci Rep ; 9(1): 11189, 2019 08 01.
Artículo en Inglés | MEDLINE | ID: mdl-31371774

RESUMEN

Competition between animal species can cause niche partitioning and shape an individual's phenotype, including its behaviour. However, little is known about effects of interspecific competition on personality, the among-individual variation in behaviour that is consistent across different spatial and temporal contexts. We investigated whether alien grey squirrels (Sciurus carolinensis) influenced the expression of personality traits in native red squirrels (Sciurus vulgaris). In Italy, alien grey squirrels replaced native reds through competition for food resources and space, reducing breeding and recruitment in the native species. We compared personality of red squirrels in red-only (no interspecific competition) and red-grey (with interspecific competition) sites, using arena-tests. The trait activity was measured by Open Field Test while sociability and avoidance were quantified by Mirror Image Stimulation test. Red squirrels co-occurring with the alien species had higher sociability scores and higher between-individual variation in sociability than in red-only sites. Differences in activity and avoidance were not significant. Personality - fitness relationships were not affected by presence or absence of grey squirrels, suggesting that the expression of sociability in red squirrels was not due to short-term selection, but was likely the result of context-related advantages when co-occurring with the competing species.


Asunto(s)
Conducta Animal/fisiología , Conducta Competitiva/fisiología , Especies Introducidas , Personalidad/fisiología , Sciuridae/fisiología , Animales , Reacción de Prevención/fisiología , Variación Biológica Poblacional/fisiología , Femenino , Aptitud Genética/fisiología , Italia , Masculino , Sciuridae/psicología , Factores Sexuales
15.
Endosc Int Open ; 7(5): E717-E727, 2019 May.
Artículo en Inglés | MEDLINE | ID: mdl-31073539

RESUMEN

Background and study aims Post-colonoscopy colorectal cancer (PCCRC) is an important quality parameter of colonoscopy. Most studies have shown that the risk for colorectal cancer is reduced after an index colonoscopy for screening or diagnostic purposes with or without polypectomy. In this study, we aimed to quantify and describe PCCRC in Belgium, including the possible relationships with patient, physician, and colonoscopy characteristics. Patients and methods Reimbursement data on colorectal related medical procedures from the Intermutualistic Agency (IMA-AIM) were linked with data on clinical and pathological staging of colorectal cancer (CRC) available at the Belgian Cancer Registry (BCR) over a period covering 9 years (2002 - 2010). Results In total, 63 518 colorectal cancers were identified in 61 616 patients between 2002 and 2010. We calculated a mean PCCRC rate of 7.6 %. PCCRC was significantly higher in older people and correlated significantly with polyp detection rate and the number of resections and procedures performed per year per physician. Conditional observed survival, given still alive 3 years since first colonoscopy, for PCCRC was worse than for CRC. Older patients and patients with invasive carcinomas had a worse outcome. Conclusions Although no quality register exists in Belgium, we were able to demonstrate that PCCRC in Belgium is directly related to the experience of the physician performing the procedure. In the absence of a quality register, utilization of population-based data sources proved to be a valuable tool to identify quality parameters.

16.
Sci Rep ; 9(1): 6085, 2019 04 15.
Artículo en Inglés | MEDLINE | ID: mdl-30988365

RESUMEN

Dense surface registration, commonly used in computer science, could aid the biological sciences in accurate and comprehensive quantification of biological phenotypes. However, few toolboxes exist that are openly available, non-expert friendly, and validated in a way relevant to biologists. Here, we report a customizable toolbox for reproducible high-throughput dense phenotyping of 3D images, specifically geared towards biological use. Given a target image, a template is first oriented, repositioned, and scaled to the target during a scaled rigid registration step, then transformed further to fit the specific shape of the target using a non-rigid transformation. As validation, we use n = 41 3D facial images to demonstrate that the MeshMonk registration is accurate, with 1.26 mm average error, across 19 landmarks, between placements from manual observers and using the MeshMonk toolbox. We also report no variation in landmark position or centroid size significantly attributable to landmarking method used. Though validated using 19 landmarks, the MeshMonk toolbox produces a dense mesh of vertices across the entire surface, thus facilitating more comprehensive investigations of 3D shape variation. This expansion opens up exciting avenues of study in assessing biological shapes to better understand their phenotypic variation, genetic and developmental underpinnings, and evolutionary history.

17.
Int J Mol Sci ; 20(6)2019 Mar 23.
Artículo en Inglés | MEDLINE | ID: mdl-30909578

RESUMEN

In Europe, the toxicological safety of genetically modified (GM) crops is routinely evaluated using rodent feeding trials, originally designed for testing oral toxicity of chemical compounds. We aimed to develop and optimize methods for advancing the use of zebrafish feeding trials for the safety evaluation of GM crops, using maize as a case study. In a first step, we evaluated the effect of different maize substitution levels. Our results demonstrate the need for preliminary testing to assess potential feed component-related effects on the overall nutritional balance. Next, since a potential effect of a GM crop should ideally be interpreted relative to the natural response variation (i.e., the range of biological values that is considered normal for a particular endpoint) in order to assess the toxicological relevance, we established natural response variation datasets for various zebrafish endpoints. We applied equivalence testing to calculate threshold equivalence limits (ELs) based on the natural response variation as a method for quantifying the range within which a GM crop and its control are considered equivalent. Finally, our results illustrate that the use of commercial control diets (CCDs) and null segregant (NS) controls (helpful for assessing potential effects of the transformation process) would be valuable additions to GM safety assessment strategies.


Asunto(s)
Alimentación Animal , Alimentos Modificados Genéticamente , Análisis de Peligros y Puntos de Control Críticos , Plantas Modificadas Genéticamente , Pez Cebra , Alimentación Animal/efectos adversos , Alimentación Animal/análisis , Animales , Suplementos Dietéticos , Análisis de los Alimentos , Inocuidad de los Alimentos , Perfilación de la Expresión Génica , Análisis de Peligros y Puntos de Control Críticos/métodos , Hígado/metabolismo , Masculino , Pruebas de Toxicidad , Zea mays , Pez Cebra/genética
18.
PLoS One ; 13(12): e0207895, 2018.
Artículo en Inglés | MEDLINE | ID: mdl-30586353

RESUMEN

Perfect bilateral symmetry is the optimal outcome of the development of bilateral traits in the absence of developmental perturbations. Any random perturbation in this perfect symmetrical state is called Fluctuating Asymmetry (FA). Many studies have been conducted on FA as an indicator of Developmental Instability (DI) and its possible link with stress and individual quality in general and with attractiveness, health and level of masculinity or femininity in humans. Most human studies of facial asymmetry use 2D pictures and a limited number of landmarks. We developed a protocol to utilize high-density 3D scans of human faces to measure the level of asymmetry. A completely symmetric spatially dense anthropometric mask with paired vertices is non-rigidly mapped on target faces using an Iterative Closest Point (ICP) registration algorithm. A set of 19 manually indicated landmarks were used to validate the mapping precision. The protocol's accuracy in FA calculation is assessed, and results show that a spatially dense approach is more accurate. In addition, it generates an integrated asymmetry estimate across the entire face. Finally, the automatic nature of the protocol provides a great advantage by omitting the tedious step of manual landmark indication on the biological structure of interest.


Asunto(s)
Antropometría/métodos , Cara/diagnóstico por imagen , Cara/fisiología , Asimetría Facial/diagnóstico por imagen , Asimetría Facial/patología , Imagenología Tridimensional/métodos , Adolescente , Adulto , Algoritmos , Femenino , Humanos , Imagenología Tridimensional/estadística & datos numéricos , Masculino , Adulto Joven
19.
Evolution ; 72(10): 2049-2056, 2018 10.
Artículo en Inglés | MEDLINE | ID: mdl-30095156

RESUMEN

Development is often temperature-dependent. We hypothesized smaller size and larger asymmetry with increasing temperatures. However, we also predicted associations with asymmetry to differ among traits that differ in their degree of functional importance (especially the functional wings in migratory birds were predicted to be more canalized), timing of development (skeletal [femur, tarsus, and humerus] vs. feather [wing and tail traits]). We analyzed a large dataset of which we included species with at least 20 specimens resulting in 5533 asymmetry values in 1593 individuals from 66 species. There was a consistent significant decrease in size with temperature across all traits. Fluctuating asymmetry (FA) for wings and femur was on average lower, suggesting higher canalization, and it decreased with migration distance, however that was not the case for the other traits. FA increased with increasing temperature for wings, but not for the other characters, where the different responses of different characters to temperature were significant. Because there was no significant three-way interaction between temperature, migration distance, and character, the asymmetry-temperature response was similar in migratory and resident species. These findings imply that climate warming reduces size of all traits and decreases developmental instability of wings in birds.


Asunto(s)
Aves/crecimiento & desarrollo , Tamaño Corporal , Cambio Climático , Alas de Animales/crecimiento & desarrollo , Animales , Dinamarca , Fenotipo , Estaciones del Año
20.
PeerJ ; 5: e3359, 2017.
Artículo en Inglés | MEDLINE | ID: mdl-28626605

RESUMEN

Disturbance from the normal developmental trajectory of a trait during growth-the so-called developmental instability-can be observed morphologically through phenodeviants and subtle deviations from perfect symmetry (fluctuating asymmetry). This study investigates the relationship between phenodeviance in the human vertebral column (as a result of axial patterning defects) and limb fluctuating asymmetry. Since both types of markers of developmental instability have been found associated with congenital abnormalities in humans, we anticipate a relationship between them if the concept of developmental instability, measured through either phenodeviants or asymmetry, would reflect an organism-wide process. Yet we did not find any support for this hypothesis. We argue that the vast differences in the developmental processes involved in both systems renders these two markers of developmental instability unrelated, in spite of their associations with other congenital abnormalities. Our results thus contribute to the growing awareness that developmental instability is not an organism-wide property.

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