1,617 research outputs found
Squirrelpox virus: assessing prevalence, transmission and environmental degradation
Red squirrels (Sciurus vulgaris) declined in Great Britain and Ireland during the last century, due to habitat loss and the introduction of grey squirrels (Sciurus carolinensis), which competitively exclude the red squirrel and act as a reservoir for squirrelpox virus (SQPV). The disease is generally fatal to red squirrels and their ecological replacement by grey squirrels is up to 25 times faster where the virus is present. We aimed to determine: (1) the seropositivity and prevalence of SQPV DNA in the invasive and native species at a regional scale; (2) possible SQPV transmission routes; and, (3) virus degradation rates under differing environmental conditions. Grey (n = 208) and red (n = 40) squirrel blood and tissues were sampled. Enzyme-linked immunosorbent assay (ELISA) and quantitative real-time polymerase chain reaction (qPCR) techniques established seropositivity and viral DNA presence, respectively. Overall 8% of squirrels sampled (both species combined) had evidence of SQPV DNA in their tissues and 22% were in possession of antibodies. SQPV prevalence in sampled red squirrels was 2.5%. Viral loads were typically low in grey squirrels by comparison to red squirrels. There was a trend for a greater number of positive samples in spring and summer than in winter. Possible transmission routes were identified through the presence of viral DNA in faeces (red squirrels only), urine and ectoparasites (both species). Virus degradation analyses suggested that, after 30 days of exposure to six combinations of environments, there were more intact virus particles in scabs kept in warm (25°C) and dry conditions than in cooler (5 and 15°C) or wet conditions. We conclude that SQPV is present at low prevalence in invasive grey squirrel populations with a lower prevalence in native red squirrels. Virus transmission could occur through urine especially during warm dry summer conditions but, more notably, via ectoparasites, which are shared by both species
Considering the Case for Biodiversity Cycles: Reexamining the Evidence for Periodicity in the Fossil Record
Medvedev and Melott (2007) have suggested that periodicity in fossil
biodiversity may be induced by cosmic rays which vary as the Solar System
oscillates normal to the galactic disk. We re-examine the evidence for a 62
million year (Myr) periodicity in biodiversity throughout the Phanerozoic
history of animal life reported by Rohde & Mueller (2005), as well as related
questions of periodicity in origination and extinction. We find that the signal
is robust against variations in methods of analysis, and is based on
fluctuations in the Paleozoic and a substantial part of the Mesozoic.
Examination of origination and extinction is somewhat ambiguous, with results
depending upon procedure. Origination and extinction intensity as defined by RM
may be affected by an artifact at 27 Myr in the duration of stratigraphic
intervals. Nevertheless, when a procedure free of this artifact is implemented,
the 27 Myr periodicity appears in origination, suggesting that the artifact may
ultimately be based on a signal in the data. A 62 Myr feature appears in
extinction, when this same procedure is used. We conclude that evidence for a
periodicity at 62 Myr is robust, and evidence for periodicity at approximately
27 Myr is also present, albeit more ambiguous.Comment: Minor modifications to reflect final published versio
A massive, quiescent galaxy at redshift of z=3.717
In the early Universe finding massive galaxies that have stopped forming
stars present an observational challenge as their rest-frame ultraviolet
emission is negligible and they can only be reliably identified by extremely
deep near-infrared surveys. These have revealed the presence of massive,
quiescent early-type galaxies appearing in the universe as early as z2,
an epoch 3 Gyr after the Big Bang. Their age and formation processes have now
been explained by an improved generation of galaxy formation models where they
form rapidly at z3-4, consistent with the typical masses and ages derived
from their observations. Deeper surveys have now reported evidence for
populations of massive, quiescent galaxies at even higher redshifts and earlier
times, however the evidence for their existence, and redshift, has relied
entirely on coarsely sampled photometry. These early massive, quiescent
galaxies are not predicted by the latest generation of theoretical models.
Here, we report the spectroscopic confirmation of one of these galaxies at
redshift z=3.717 with a stellar mass of 1.710 M whose
absorption line spectrum shows no current star-formation and which has a
derived age of nearly half the age of the Universe at this redshift. The
observations demonstrates that the galaxy must have quickly formed the majority
of its stars within the first billion years of cosmic history in an extreme and
short starburst. This ancestral event is similar to those starting to be found
by sub-mm wavelength surveys pointing to a possible connection between these
two populations. Early formation of such massive systems is likely to require
significant revisions to our picture of early galaxy assembly.Comment: 6 pages, 7 figures. This is the final preprint corresponding closely
to the published version. Uploaded 6 months after publication in accordance
with Nature polic
Mindfulness-based interventions in epilepsy: a systematic review
Mindfulness based interventions (MBIs) are increasingly used to help patients cope with physical and mental long-term conditions (LTCs). Epilepsy is associated with a range of mental and physical comorbidities that have a detrimental effect on quality of life (QOL), but it is not clear whether MBIs can help. We systematically reviewed the literature to determine the effectiveness of MBIs in people with epilepsy. Medline, Cochrane Central Register of Controlled Trials, EMBASE, CINAHL, Allied and Complimentary Medicine Database, and PsychInfo were searched in March 2016. These databases were searched using a combination of subject headings where available and keywords in the title and abstracts. We also searched the reference lists of related reviews. Study quality was assessed using the Cochrane Collaboration risk of bias tool. Three randomised controlled trials (RCTs) with a total of 231 participants were included. The interventions were tested in the USA (n = 171) and China (Hong Kong) (n = 60). Significant improvements were reported in depression symptoms, quality of life, anxiety, and depression knowledge and skills. Two of the included studies were assessed as being at unclear/high risk of bias - with randomisation and allocation procedures, as well as adverse events and reasons for drop-outs poorly reported. There was no reporting on intervention costs/benefits or how they affected health service utilisation. This systematic review found limited evidence for the effectiveness of MBIs in epilepsy, however preliminary evidence suggests it may lead to some improvement in anxiety, depression and quality of life. Further trials with larger sample sizes, active control groups and longer follow-ups are needed before the evidence for MBIs in epilepsy can be conclusively determined
Antimicrobial Stewardship from Policy to Practice: Experiences from UK Antimicrobial Pharmacists
Antimicrobial stewardship in the UK has evolved dramatically in the last 15 years. Factors driving this include initial central funding for specialist pharmacists and mandatory reductions in healthcare-associated infections (particularly Clostridium difficile infection). More recently, the introduction of national stewardship guidelines, and an increased focus on stewardship as part of the UK five-year antimicrobial resistance strategy, have accelerated and embedded developments. Antimicrobial pharmacists have been instrumental in effecting changes at an organizational and national level. This article describes the evolution of the antimicrobial pharmacist role, its impact, the progress toward the actions listed in the five-year resistance strategy, and novel emerging areas in stewardship in the UK
Fortnightly changes in water transport direction across the mouth of a narrow estuary
This research investigates the dynamics of the axial
tidal flow and residual circulation at the lower Guadiana
Estuary, south Portugal, a narrow mesotidal estuary with low
freshwater inputs. Current data were collected near the deepest
part of the channel for 21 months and across the channel
during two (spring and neap) tidal cycles. Results indicate
that at the deep channel, depth-averaged currents are stronger
and longer during the ebb at spring and during the flood at
neap, resulting in opposite water transport directions at a
fortnightly time scale. The net water transport across the entire
channel is up-estuary at spring and down-estuary at neap, i.e.,
opposite to the one at the deep channel. At spring tide, when
the estuary is considered to be well mixed, the observed
pattern of circulation (outflow in the deep channel, inflow
over the shoals) results from the combination of the Stokes
transport and compensating return flow, which varies laterally
with the bathymetry. At neap tide (in particular for those of
lowest amplitude each month), inflows at the deep channel are
consistently associated with the development of gravitational
circulation. Comparisons with previous studies suggest that
the baroclinic pressure gradient (rather than internal tidal
asymmetries) is the main driver of the residual water transport.
Our observations also indicate that the flushing out of the
water accumulated up-estuary (at spring) may also produce
strong unidirectional barotropic outflow across the entire
channel around neap tide.info:eu-repo/semantics/publishedVersio
The developmental regulator Pax6 is essential for maintenance of islet cell function in the adult mouse pancreas
The transcription factor Pax6 is a developmental regulator with a crucial role in development of the eye, brain, and olfactory system. Pax6 is also required for correct development of the endocrine pancreas and specification of hormone producing endocrine cell types. Glucagon-producing cells are almost completely lost in Pax6-null embryos, and insulin-expressing beta and somatostatin-expressing delta cells are reduced. While the developmental role of Pax6 is well-established, investigation of a further role for Pax6 in the maintenance of adult pancreatic function is normally precluded due to neonatal lethality of Pax6-null mice. Here a tamoxifen-inducible ubiquitous Cre transgene was used to inactivate Pax6 at 6 months of age in a conditional mouse model to assess the effect of losing Pax6 function in adulthood. The effect on glucose homeostasis and the expression of key islet cell markers was measured. Homozygous Pax6 deletion mice, but not controls, presented with all the symptoms of classical diabetes leading to severe weight loss requiring termination of the experiment five weeks after first tamoxifen administration. Immunohistochemical analysis of the pancreata revealed almost complete loss of Pax6 and much reduced expression of insulin, glucagon, and somatostatin. Several other markers of islet cell function were also affected. Notably, strong upregulation in the number of ghrelin-expressing endocrine cells was observed. These findings demonstrate that Pax6 is essential for adult maintenance of glucose homeostasis and function of the endocrine pancreas
Enzymatic processing of protein-based fibers
Wool and silk are major protein fiber materials used by the textile industry. Fiber protein structure-function relationships are briefly described here, and the major enzymatic processing routes for textiles and other novel applications are deeply reviewed. Fiber biomodification is described here with various classes of enzymes such as protease, transglutaminase, tyrosinase, and laccase. It is expected that the reader will get a perspective on the research done as a basis for new applications in other areas such as cosmetics and pharma.This work was financially supported by the National Natural Science Foundation of China (21274055,51373071, 31201134 and 31470509), the Program for New Century Excellent Talents in University (NCET-12-0883), the Program for Changjiang Scholars and Innovative Research Team in University (IRT1135), the Jiangsu Provincial Natural Science Foundation of China (BK2012112), and the Fundamental Research Funds for the Central Universities (JUSRP51312B)
Digital reconstruction of the inner ear of Leptictidium auderiense (Leptictida, Mammalia) and North American leptictids reveals new insight into leptictidan locomotor agility
Leptictida are basal Paleocene to Oligocene eutherians from Europe and North America comprising species with highly specialized postcranial features including elongated hind limbs. Among them, the European Leptictidium was probably a bipedal runner or jumper. Because the semicircular canals of the inner ear are involved in detecting angular acceleration of the head, their morphometry can be used as a proxy to elucidate the agility in fossil mammals. Here we provide the first insight into inner ear anatomy and morphometry of Leptictida based on high-resolution computed tomography of a new specimen of Leptictidium auderiense from the middle Eocene Messel Pit (Germany) and specimens of the North American Leptictis and Palaeictops. The general morphology of the bony labyrinth reveals several plesiomorphic mammalian features, such as a secondary crus commune. Leptictidium is derived from the leptictidan groundplan in lacking the secondary bony lamina and having proportionally larger semicircular canals than the leptictids under study. Our estimations reveal that Leptictidium was a very agile animal with agility score values (4.6 and 5.5, respectively) comparable to Macroscelidea and extant bipedal saltatory placentals. Leptictis and Palaeictops have lower agility scores (3.4 to 4.1), which correspond to the more generalized types of locomotion (e.g., terrestrial, cursorial) of most extant mammals. In contrast, the angular velocity magnitude predicted from semicircular canal angles supports a conflicting pattern of agility among leptictidans, but the significance of these differences might be challenged when more is known about intraspecific variation and the pattern of semicircular canal angles in non-primate mammals
Role for the thromboxane A 2 receptor β-isoform in the pathogenesis of intrauterine growth restriction
Intrauterine growth restriction (IUGR) is a pathology of pregnancy that results in failure of the fetus to reach its genetically determined growth potential. In developed nations the most common cause of IUGR is impaired placentation resulting from poor trophoblast function, which reduces blood flow to the fetoplacental unit, promotes hypoxia and enhances production of bioactive lipids (TXA 2 and isoprostanes) which act through the thromboxane receptor (TP). TP activation has been implicated as a pathogenic factor in pregnancy complications, including IUGR; however, the role of TP isoforms during pregnancy is poorly defined. We have determined that expression of the human-specific isoform of TP (TPβ) is increased in placentae from IUGR pregnancies, compared to healthy pregnancies. Overexpression of TPα enhanced trophoblast proliferation and syncytialisation. Conversely, TPβ attenuated these functions and inhibited migration. Expression of the TPβ transgene in mice resulted in growth restricted pups and placentae with poor syncytialisation and diminished growth characteristics. Together our data indicate that expression of TPα mediates normal placentation; however, TPβ impairs placentation, and promotes the development of IUGR, and represents an underappreciated pathogenic factor in humans
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