Effects of different head–neck positions on the larynges of ridden horses

Hyperflexion, that is the strong deflection of the horse's head, poll and neck, is a prevalent training technique in equitation. Hyperflexion has come under criticism in recent years for being suspected of affecting the horses' well‐being contrary to animal welfare. The goal of the present study is a comparison between the impacts of different poll‐neck positions on findings in the upper respiratory tract of ridden horses. For this purpose, video recordings of the larynges of 14 horses were taken using an overground endoscope. The videos were recorded at rest and during three different riding phases: firstly, in a stretching posture, secondly, in a working position and, thirdly, in hyperflexion. A comparison between the analyses of the working position and hyperflexion phases revealed a significant reduction in the laryngeal opening area (p = 0.001) with a value of 8.2 ± 5.0%. Furthermore, other parameters of the larynx evaluated also showed a significant diminishment. These changes did not correlate with the age of the horses or their level of education, and they were independent of the individual anatomical conditions of the poll‐neck region. In summary, it can be stated that hyperflexion causes a considerable compression of the larynx.     

Identification of focus areas for Australian Bat Lyssavirus potential exposure prevention in the Metro North Hospital and Health Service region

Australian Bat Lyssavirus (ABLV) is a fatal rabies‐like disease spread to humans from bats. All people who report bat bites or scratches in Queensland are considered potentially exposed to ABLV and are followed up and treated to prevent ABLV. Preventing members of the public intentionally interacting with bats will reduce the number of potential exposures to ABLV. In order to target public health messaging, this study examines the epidemiology of potential ABLV exposures in Metro North Hospital and Health Service (HHS), a region of Queensland that encompasses metro and rural areas in the south‐east of the state. People who intentionally handled bats during the study period were more likely to be adult (93%), male (60%), scratched (51%) by a megabat (72%) and been potentially exposed while rescuing the bat when it was trapped or injured (72%). The number of potential exposures reported in Queensland has increased since 2013; the same year, a Queensland child died of ABLV. Seasonally, exposures are more common during bat breeding and nursing periods when bats are more active (summer to autumn). Although there were more notifications in a band stretching north from the inner city to northern metro suburbs, notification rates were higher in large rural statistical areas in the north of the HHS. These data will be used to develop geographically targeted ABLV prevention messaging for the general public.     

Interferon-beta-related DNA is dispersed in the human genome

Interferon-beta 1 (IFN-beta 1) complementary DNA was used as a hybridization probe to isolate human genomic DNA clones lambda B3 and lambda B4 from a human genomic DNA library. Blot-hybridization procedures and partial nucleotide sequencing revealed that lambda B3 is related to IFN-beta 1 (and more distantly to IFN-alpha 1). Analyses of DNA obtained from a panel of human-rodent somatic cell hybrids that were probed with DNA derived from lambda B3 showed that lambda B3 is on human chromosome 2. Similar experiments indicated that lambda B4 is not on human chromosomes 2, 5, or 9. The finding that DNA related to the IFN-beta 1 gene (and IFN-alpha 1 gene) is dispersed in the human genome raises new questions about the origins of the interferon genes.     

Harvesting natural populations in a randomly fluctuating environment

As harvesting effort and yield are increased, animal populations that are being harvested for sustained yield will take longer to recover from environmentally imposed disturbances. One consequence is that the coefficient of variation (the relative variance) of the yield increases as the point of maximum sustained yield (MSY) is approached. When overexploitation has resulted in a population smaller than that for MSY, high effort produces a low average yield with high variance. These observations accord with observed trends in several fish and whaling industries. We expect these effects to be more pronounced for a harvesting strategy based on constant quotas than for one based on constant effort. Although developed in a MSY context, the conclusions also apply if the aim is to maximize the present value of (discounted) net economic revenue.     

Species turnover rates on islands: dependence on census interval

Measurements of species turnover in island bird communities demonstrate two trends with increasing census interval t: (i) Apparent turnover rates T decrease greatly with t, and (ii) the coefficient of variation of T decreases asymptotically to a constant value. These effects are predicted by a statistical model whose parameters are the immigration and extinction probabilities of each species. Available bird censuses at intervals of decades underestimate turnover rates by about an order of magnitude.     

Ecology. Species-area relations in tropical forests

A power law called the species-area relationship describes the finding that the number of species is proportional to the size of the area in which they are found, raised to an exponent (usually, a number between 0.2 and 0.3). In their Perspective, May and Stumpf discuss new results from a survey of five tropical forest census areas containing a total of a million trees. They explain how this large data set can be used to fine-tune the existing power law so that it provides a better prediction of species diversity in small census samples.