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The recent description of the nevadioid trilobite Buenellus chilhoweensis Webster and Hageman, 2018 established the presence of early Cambrian Montezuman Stage (Cambrian Series 2, Stage 3) faunas in the Murray Shale of Chilhowee Mountain, Tennessee. The description recognized the oldest known age-diagnostic Cambrian trilobite from the Laurentian margin of the former Iapetus Ocean since Buenellus Blaker, 1988 is known otherwise only from the Sirius Passet Lagerstätte on the Innuitian margin of North Greenland. The bivalved arthropods Isoxys chilhoweanus Walcott, 1890 and Indota tennesseensis (Resser, 1938a) have also been described from the Murray Shale, but hyolithids appear to be the dominant body fossils in terms of diversity and abundance. Although poorly preserved, the hyolithids occurring together with Buenellus chilhoweensis are described to improve understanding of the Murray Shale biota. The hyolith assemblages of the Murray Shale and Sirius Passet Lagerstätte are not closely similar, although the poor preservation of both hinders comparison.
Most basic science research has focused on overt stroke caused by blockage of major blood vessels. Less attention has been paid to small vessel disease giving rise to covert stroke that often leads to vascular cognitive impairment (VCI). One reason for this may be the relative lack of relevant animal models. This talk will describe a model of VCI induced in middle-aged Sprague-Dawley rats exposed to a diet high in saturated fats, salt and refined sugar (HFSS). In Experiment 1, rats fed HFSS and subjected to a small mediodorsal (MD) thalamic stroke with or without concomitant cerebral hypoperfusion experienced significant executive dysfunction. In Experiment 2, dietary influences on functional, physiological and anatomical parameters were assessed. We found significant hypertension, blockage of brain microvessels (2-photon microscopy) and white matter atrophy in HFSS diet animals. As in Experiment 1, profound, specific set-shifting executive dysfunction was noted following both small MD infarcts (0.332 mm3) and the HFSS diet. In summary, these data describe a middle-aged animal model of VCI that includes clinically-relevant metabolic disturbances and small vessel disease and as such may be helpful in developing new cognitive therapies.
Understanding viral transmission dynamics within populations of reservoir hosts can facilitate greater knowledge of the spillover of emerging infectious diseases. While bat-borne viruses are of concern to public health, investigations into their dynamics have been limited by a lack of longitudinal data from individual bats. Here, we examine capture–mark–recapture (CMR) data from a species of Australian bat (Myotis macropus) infected with a putative novel Alphacoronavirus within a Bayesian framework. Then, we developed epidemic models to estimate the effect of persistently infectious individuals (which shed viruses for extensive periods) on the probability of viral maintenance within the study population. We found that the CMR data analysis supported grouping of infectious bats into persistently and transiently infectious bats. Maintenance of coronavirus within the study population was more likely in an epidemic model that included both persistently and transiently infectious bats, compared with the epidemic model with non-grouping of bats. These findings, using rare CMR data from longitudinal samples of individual bats, increase our understanding of transmission dynamics of bat viral infectious diseases.
Neurocognitive performance deficits have been observed in mood disorder patients and their unaffected relatives and may therefore qualify as endophenotypes. However, the precise time course of neurocognitive deficits has not been studied so that it is unknown whether neurocognitive abnormalities reflect the early effects of familial vulnerability to mood disorders or if they emerge at illness onset.
A neuropsychological test battery was administered at baseline and after a 2-year follow-up interval in 111 initially unaffected young adults at high familial risk of mood disorders and 93 healthy controls (HC). During the follow-up period, 20 high-risk subjects developed major depressive disorder (HR-MDD), with the remainder remaining well (HR-well). Linear mixed-effects models were used to investigate differences and longitudinal changes in the domains of attentional processing, working memory, verbal learning and memory, and cognitive flexibility.
Reduced long delay verbal memory and extradimensional set-shifting performance across both time points were found in the HR-well group relative to controls. The HR-MDD group displayed decreased extradimensional set-shifting abilities across both time points as compared with the HC group only. There were no significant performance differences between the two high-risk groups.
Reduced verbal memory and cognitive flexibility are familial trait markers for vulnerability to mood disorders in individuals with a close family history of bipolar disorder. Both neurocognitive performance deficits appear to be relatively stable over a 2-year time period and do not appear to be linked to the onset of MDD. These findings support their use as stable quantitative endophenotypes for mood disorders.
The rapid rise in syphilis cases has prompted a number of public health campaigns to assist men who have sex with men (MSM) recognize and present early with symptoms. This study aimed to investigate the temporal trend of the duration of self-report symptoms and titre of rapid plasma reagin (RPR) in MSM with infectious syphilis. Seven hundred and sixty-one syphilis cases in MSM diagnosed at the Melbourne Sexual Health Centre (MSHC) from 2007–2013 were reviewed. Median duration of symptoms and RPR titres in each year were calculated. The median durations of symptoms with primary and secondary syphilis were 9 [interquartile range (IQR) 6–14] days and 14 (IQR 7–30) days, respectively. The overall median titre of RPR in secondary syphilis (median 128, IQR 64–256) was higher than in primary syphilis (median 4, IQR 1–32) and in early latent syphilis (median 32, IQR 4–64). The median duration of symptoms for primary syphilis, secondary syphilis and titre of RPR level did not change over time. Public health campaigns were not associated with a significant shorter time from onset of symptoms to treatment. Alternative strategies such as more frequent testing of MSM should be promoted to control the syphilis epidemic in Australia.
The effects of management on ecosystem diversity, structure and function must be understood for the sustainable integration of conservation and development. A potential source of experimentation and learning in ecosystem management is the array of private protected areas worldwide. Autonomous management systems can be seen as natural experiments, presenting an opportunity to explore the consequences of manipulating ecosystem properties. By quantifying management diversity and developing an index of management intensity we assessed the ecological correlates of private protected area management within the savannah biome in South Africa. Management intensity is positively correlated with herbivore density, predator density and ecotourism lodge density and negatively with herbivore community heterogeneity, reintroduction success and primary productivity at the local protected area scale. However, these trade-offs are tantamount to functional diversity as different management systems play unique roles in the regional socio-ecological and socio-economic systems, which range from animal production centres high in commercial value to low density areas that may sustain landscape processes. Furthermore, fenced private protected areas are necessary to safeguard rare species that cannot sustain viable populations in altered ecosystems. Thus, when considered at the regional scale, a private protected area network that constitutes a patchwork of management systems will create a coincident conservation and production landscape. We suggest that maintaining management heterogeneity will provide net benefits to biodiversity and potentially galvanize locally sustainable, wildlife-based economies.
Bat flies are obligate ectoparasites of bats and it has been hypothesized that they may be involved in the transmission of Bartonella species between bats. A survey was conducted to identify whether Cyclopodia greefi greefi (Diptera: Nycteribiidae) collected from Ghana and 2 islands in the Gulf of Guinea harbour Bartonella. In total, 137 adult flies removed from Eidolon helvum, the straw-coloured fruit bat, were screened for the presence of Bartonella by culture and PCR analysis. Bartonella DNA was detected in 91 (66·4%) of the specimens examined and 1 strain of a Bartonella sp., initially identified in E. helvum blood from Kenya, was obtained from a bat fly collected in Ghana. This is the first study, to our knowledge, to report the identification and isolation of Bartonella in bat flies from western Africa.
Benchmarking, the comparison of efficiency measures of an organization against those of other organizations, is widely used in industry, medical practice and agriculture as a means of learning where practice can be improved. This could be used by conservationists for routine repeatable activities, such as the treatment of invasive species or the survival rate of transplanted plants. We give three examples of the benefits of cross-site comparisons: grazing management in South Africa, husbandry of captive penguins and management of lagoons for wading birds. Benchmarking, by comparing effectiveness with others, is the initial stage in identifying weaknesses and leads on to learning how to improve through cross-site comparisons, comparisons with better performers or examination of the published literature. We suggest that the term best practice, which is often used as part of benchmarking, is unsuitable as it implies a comparison of all options, which rarely takes place, and it is subject to change as knowledge and techniques develop. An alternative term is current effective practice.
Binary logit regression models were used to estimate factors affecting adoption of recommended management practices. Variables analyzed include aspects of farm structure, human capital, farm objectives, and production system employed by the producer. Results reveal that operation size and dependency upon income from the stocker operation, in particular, influence the adoption of recommended practices. Older producers and those pursuing a year-round production strategy were found to lag in adoption.
Repaired shell injuries are reported in 11 specimens including six genera and eight species of gastropods from the upper Middle Ordovician (Caradoc) Kullsberg Limestone and the Upper Ordovician (Ashgill) Boda Limestone, Siljan district, Sweden. The specimens are of different sizes and morphologies, including one isostrophic, three low-spired, and six moderately high-spired turbinate forms. Single and repeated episodes of shell damage and subsequent repair are preserved, the breaks ranging from simple arcuate or scalloped fractures to removal of large sections of the apertural margin. Both early and late growth stages show damage, but the injuries are usually restricted to only one whorl. No shell repairs were discovered on the 65 more or less complete specimens of the subulitids, although the smooth shell makes observation difficult. Injuries in the Siljan samples are found in both microgastropods and large specimens, but the sample is too small for meaningful quantification. The shell repair frequency is about 7 percent, based on examination of 404 specimens (54 from Kullsberg Limestone and 350 from Boda Limestone). Most of the repaired injuries are attributed to failed predation, adding significantly to the Lower Paleozoic documentation of predation on gastropods. The gastropod shells are morphologically weak by modern standards, but do show some architectural strengthening features such as narrow apertures, collabral or spiral threads, and other ornamentation. The identity of the predator(s) is unknown.
The marine offshore shelf mudstones of the Early Cambrian Buen Formation at Sirius Passet, North Greenland, contain a rich Konservat-Lagerstätte which includes abundant well-preserved material of the bivalved arthropod Isoxys volucris new species. The new material confirms Isoxys Walcott, 1890 as a component of the earliest arthropod faunas worldwide. Isoxys species are known from the Early Cambrian of Spain, Siberia, South Australia and Southwest China and also from the Early to Middle Cambrian of Laurentian North America. Isoxys occurs in the Redlichiid, Bigotinid and Olenellid trilobite faunal realms but is restricted to within tropical/subtropical regions, attesting to possible paleolatitudinal controls on its distribution. Isoxys resembles some phyllocarid and bradoriid arthropods but without knowledge of its soft-parts the affinity of the genus remains uncertain.
Marine shelf siliciclastics of the early Cambrian Buen Formation of North Greenland have yielded the earliest abundant, well localised Bradoriida (Arthropoda) from the Laurentian part of North America: the shelf-dwelling Petrianna gen. nov. Petrianna apparently has a fairly rigid, phosphatic shell. Its assignment to the Cambriidae, a family markedly dissimilar morphologically from the phosphatocopines (the only Bradoriida hitherto regarded as having a primary phosphatic shell), implies rejection of the criterion of carapace composition in the ordinal/subordinal classification of Bradoriida.
Petrianna confirms the Bradoriida as a consistent component of the earliest arthropod faunas. Cambriids are currently known only from the early Cambrian of Greenland, Siberia and China and offer potential for correlation. Cambriid occurrences span parts of the Redlichiid, Olenellid and Bigotinid trilobite faunal realms but are known only from tropical/subtropical regions, thus indicating possible palaeolatitudinal controls on their distribution.
Animal performance from grassland is dependant both on the grass growth achieved and the efficiency of utilisation. The Grassland Research Institute and ADAS conducted a series of trials (GM 20) which showed grass growth to be mainly influenced by the available water capacity of the soil, summer rainfall and altitude. This gives a site class which together with the fertilizer used determines the quantity of herbage grown.
Less is known of the variation in utilisation of the grass grown. This analysis has been undertaken to assess the levels of grassland utilisation found on dairy farms of England and Wales.
This paper deals, in the main, with aluminium alloys and steels that are currently available on a commercial basis or are likely to become available in the near future. It highlights the more significant improvements made during the past two decades.
Aircraft structures have been built predominantly of aluminium alloys since the Second World War and, although certain improvements have been made over this period, the alloy systems used have changed little essentially because the alloys available have been limited by the solid solubilities of the selected solute elements at safe solution temperatures. The slow but certain development of novel production routes including fibre and whisker reinforcement of metals, powder production and rapid solidification techniques will circumvent this limitation by the turn of the century.
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