170 research outputs found

    Heterosexual interactions of pairs of laboratory-housed stumptail macaques (Macaca arctoides) under continuous observation with closed-circuit video recording

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    Female-male interaction of heterosexual pairs of stumptail macaques, housed together continuously, was studied 24 hr per day using closed-circuit video recording. Two pairs were studied for approximately 2 months each. Although no generalizations can be made from such a small sample, no aspect of behavioral interaction varied significantly with the stage of the menstrual cycle of the female partner. Copulation occurred regularly but only during the daylight hours. Both pairs showed several peak ejaculation days (5-21 ejaculations/day), which were distributed throughout the entire menstrual cycle. In general, the highest number of ejaculations was observed to occur when the animals were put together either for the first time or following a separation of a few days. In one pair the female became pregnant, and from the fifth week of pregnancy onward there was a gradual increase in male aggression, coinciding with a decrease in male sexual and grooming behavior. In a second study eight different pairs were observed during the first day together and male copulatory behavior was studied. Two patterns of copulatory behavior could be discerned: pairs displaying a high number of ejaculations (19-38) and pairs displaying a low number of ejaculations (4-8). With regard to the interejaculatory interval (IEI), the male stumptail appeared to be unique. In contrast to what has been reported for other mammals, i.e., a steady increase in IEI with subsequent ejaculations, the stumptail showed increasing IEIs only during the first three to four, as well as between the last, ejaculations; in between, the IEI remained relatively constant. The maximum number of consecutive ejaculations observed was 38, displayed during a 10-hr time period (mean (± SEM)IEI, 12.9 ± 3.5 min)

    Extragalactic Peaked-Spectrum Radio Sources at Low-Frequencies are Young Radio Galaxies

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    © 2022 Dementia and Geriatric Cognitive Disorders. All rights reserved. This is an Open Access article, published by EDP Sciences, under the terms of the Creative Commons Attribution License (https://creativecommons.org/licenses/by/4.0).We present a sample of 373 peaked-spectrum (PS) sources with spectral peaks around 150 MHz, selected using a subset of the two LOw Frequency ARray (LOFAR) all-sky surveys, the LOFAR Two Meter Sky Survey and the LOFAR LBA Sky Survey. These LOFAR surveys are the most sensitive low-frequency widefield surveys to date, allowing us to select low-luminosity peaked-spectrum sources. Our sample increases the number of known PS sources in our survey area by a factor 50. The 5 GHz luminosity distribution of our PS sample shows we sample the lowest luminosity PS sources to date by nearly an order of magnitude. Since high-frequency gigahertz-peaked spectrum sources and compact steep-spectrum sources are hypothesised to be the precursors to large radio galaxies, we investigate whether this is also the case for our sample of low-frequency PS sources. Using optical line emission criteria, we find that our PS sources are predominately high-excitation radio galaxies instead of low-excitation radio galaxies, corresponding to a quickly evolving population. We compute the radio source counts of our PS sample, and find they are scaled down by a factor of ≈40 compared to a general sample of radio-loud active galactic nuclei (AGN). This implies that the lifetimes of PS sources are 40 times shorter than large-scale radio galaxies if their luminosity functions are identical. To investigate this, we compute the first radio luminosity function for a homogeneously selected PS sample. We find that for 144 MHz luminosities ≳1025 W Hz-1, the PS luminosity function has the same shape as an unresolved radio-loud AGN population, but shifted down by a factor of ≈-pagination10. We interpret this as strong evidence that these high-luminosity PS sources evolve into large-scale radio-loud AGN. For local low-luminosity PS sources, there is a surplus of PS sources, which we hypothesise to be the addition of frustrated PS sources that do not evolve into large-scale AGN.Peer reviewe

    Persistence of parental-reported asthma at early ages:A longitudinal twin study

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    Background: Currently, we cannot predict whether a pre-school child with asthma-like symptoms will have asthma at school age. Whether genetic information can help in this prediction depends on the role of genetic factors in persistence of pre-school to school-age asthma. We examined to what extent genetic and environmental factors contribute to persistence of asthma-like symptoms at ages 3 to asthma at age 7 using a bivariate genetic model for longitudinal twin data. Methods: We performed a cohort study in monozygotic and dizygotic twins from the Netherlands Twin Register (NTR, n = 21,541 twin pairs). Bivariate genetic models were fitted to longitudinal data on asthma-like symptoms reported by parents at age 3 and 7 years to estimate the contribution of genetic and environmental factors. Results: Bivariate genetic modeling showed a correlation on the liability scale between asthma-like symptoms at age 3 and asthma at age 7 of 0.746 and the contribution of genetics was estimated to be 0.917. The genetic analyses indicated a substantial influence of genetic factors on asthma-like symptoms at ages 3 and 7 (heritability 80% and 90%, respectively); hence, contribution of environmental factors was low. Persistence was explained by a high (rg = 0.807) genetic correlation. Conclusion: Parental-reported asthma-like symptoms at age 3 and asthma at age 7 are highly heritably. The phenotype of asthma-like symptoms at age 3 and 7 was highly correlated and mainly due to heritable factors, indicating high persistence of asthma development over ages 3 and 7

    Dutch dairy farmers' perspectives on culling reasons and strategies

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    Since the abolishment of the milk quota system in Europe in 2014 and the introduction of environmental policies such as the phosphate rights system in the Netherlands, the reasons for culling dairy cows might have changed. The aim of this study was to determine the culling reasons for dairy cattle and to identify farmers' culling strategies and their intentions regarding the alteration of indicated culling strategies. To this end, an online questionnaire was distributed among dairy farmers nationally that resulted in 207 responses. Results showed that the most frequent culling reasons were related to problems with reproduction, udder, and hoof health. Primiparous cows were primarily culled for miscellaneous reasons such as injury, reproduction failure, and low milk yield. Multiparous cows were culled predominantly for reproduction failure, udder health and hoof health reasons. Most respondents indicated that they consider formulating a culling strategy, based on certain rules of thumb regarding the most common reasons for culling. Most farmers also reported that culling decisions on their farms were perceived to be unavoidable, though reproductive culling decisions are primarily voluntary. Most respondents stated that they intended to reduce the culling rate for better economic gain did not intend to alter the amount of replacement stock reared. The applied rules of thumb regarding culling strategies do not seem to have changed since the policy changes in dairy farming. The question remains whether farmers' rules of thumb might have made them unaware of the actual economic consequences of their culling strategies under the altered situation

    Early-life antibiotic use and risk of asthma and eczema:results of a discordant twin study

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    RATIONALE: Early-life antibiotic use has been associated with development of atopic diseases, but the aetiology remains unclear. To elucidate aetiology, we used a discordant twin design to control for genetic and environmental confounding. METHODS: We conducted a retrospective cohort study in twins (3-10 years) from the Netherlands Twin Register (NTR, n=34 352) and a replication study at age 9 in the Childhood and Adolescent Twin Study in Sweden (CATSS, n=7906). Antibiotic use was recorded at 0-2 years. Doctor diagnosed asthma and eczema were reported by parents when children were 3-12 years in both cohorts. Individuals were included in unmatched analyses and in co-twin control analyses with disease discordant twin pairs. RESULTS: Early-life antibiotic use was associated with increased risk of asthma (NTR OR 1.34 95%CI 1.28-1.41; CATSS 1.45 95%CI 1.34-1.56) and eczema (NTR OR 1.08 95%CI 1.03-1.13; CATSS 1.07 95%CI 1.01-1.14) in unmatched analyses. Co-twin analyses in mono- and dizygotic twin pairs showed similar results for asthma (NTR 1.54 95%CI 1.20-1.98 and CATSS 2.00 95%CI 1.28-3.13), but opposing results for eczema in NTR (0.99 95%CI 0.80-1.25) and CATSS (1.67 95%CI 1.12-2.49). The risk of asthma increased for antibiotics prescribed for respiratory infections (CATSS 1.45 95%CI 1.34-1.56), but not for antibiotics commonly used for urinary tract/skin infections (CATSS 1.02 95%CI 0.88-1.17). CONCLUSION: Children exposed to early-life antibiotic use, particularly prescribed for respiratory infections, may be at higher risk of asthma. This risk can still be observed, when correcting for genetic and environmental factors. Our results could not elucidate whether the relationship between early-life antibiotic use and eczema is confounded by familial and genetic factors

    Dispelling urban myths about default uncertainty factors in chemical risk assessment - Sufficient protection against mixture effects?

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    © 2013 Martin et al.; licensee BioMed Central LtdThis article has been made available through the Brunel Open Access Publishing Fund.Assessing the detrimental health effects of chemicals requires the extrapolation of experimental data in animals to human populations. This is achieved by applying a default uncertainty factor of 100 to doses not found to be associated with observable effects in laboratory animals. It is commonly assumed that the toxicokinetic and toxicodynamic sub-components of this default uncertainty factor represent worst-case scenarios and that the multiplication of those components yields conservative estimates of safe levels for humans. It is sometimes claimed that this conservatism also offers adequate protection from mixture effects. By analysing the evolution of uncertainty factors from a historical perspective, we expose that the default factor and its sub-components are intended to represent adequate rather than worst-case scenarios. The intention of using assessment factors for mixture effects was abandoned thirty years ago. It is also often ignored that the conservatism (or otherwise) of uncertainty factors can only be considered in relation to a defined level of protection. A protection equivalent to an effect magnitude of 0.001-0.0001% over background incidence is generally considered acceptable. However, it is impossible to say whether this level of protection is in fact realised with the tolerable doses that are derived by employing uncertainty factors. Accordingly, it is difficult to assess whether uncertainty factors overestimate or underestimate the sensitivity differences in human populations. It is also often not appreciated that the outcome of probabilistic approaches to the multiplication of sub-factors is dependent on the choice of probability distributions. Therefore, the idea that default uncertainty factors are overly conservative worst-case scenarios which can account both for the lack of statistical power in animal experiments and protect against potential mixture effects is ill-founded. We contend that precautionary regulation should provide an incentive to generate better data and recommend adopting a pragmatic, but scientifically better founded approach to mixture risk assessment. © 2013 Martin et al.; licensee BioMed Central Ltd.Oak Foundatio

    Medication use in uncontrolled pediatric asthma:Results from the SysPharmPediA study

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    Background: Uncontrolled pediatric asthma has a large impact on patients and their caregivers. More insight into determinants of uncontrolled asthma is needed. We aim to compare treatment regimens, inhaler techniques, medication adherence and other characteristics of children with controlled and uncontrolled asthma in the: Systems Pharmacology approach to uncontrolled Paediatric Asthma (SysPharmPediA) study. Material and methods: 145 children with moderate to severe doctor-diagnosed asthma (91 uncontrolled and 54 controlled) aged 6–17 years were enrolled in this multicountry, (Germany, Slovenia, Spain, and the Netherlands) observational, case-control study. The definition of uncontrolled asthma was based on asthma symptoms and/or exacerbations in the past year. Patient-reported adherence and clinician-reported medication use were assessed, as well as lung function and inhalation technique. A logistic regression model was fitted to assess determinants of uncontrolled pediatric asthma. Results: Children in higher asthma treatment steps had a higher risk of uncontrolled asthma (OR (95%CI): 3.30 (1.56–7.19)). The risk of uncontrolled asthma was associated with a larger change in FEV1% predicted post and pre-salbutamol (OR (95%CI): 1.08 (1.02–1.15)). Adherence and inhaler techniques were not associated with risk of uncontrolled asthma in this population. Conclusion: This study showed that children with uncontrolled moderate-to-severe asthma were treated in higher treatment steps compared to their controlled peers, but still showed a higher reversibility response to salbutamol. Self-reported adherence and inhaler technique scores did not differ between controlled and uncontrolled asthmatic children. Other determinants, such as environmental factors and differences in biological profiles, may influence the risk of uncontrolled asthma in this moderate to severe asthmatic population
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