240 research outputs found
The optical afterglow of the short gamma-ray burst GRB 050709
It has long been known that there are two classes of gamma-ray bursts (GRBs),
mainly distinguished by their durations. The breakthrough in our understanding
of long-duration GRBs (those lasting more than ~2 s), which ultimately linked
them with energetic Type Ic supernovae, came from the discovery of their
long-lived X-ray and optical afterglows, when precise and rapid localizations
of the sources could finally be obtained. X-ray localizations have recently
become available for short (duration <2 s) GRBs, which have evaded optical
detection for more than 30 years. Here we report the first discovery of
transient optical emission (R-band magnitude ~23) associated with a short
burst; GRB 050709. The optical afterglow was localized with subarcsecond
accuracy, and lies in the outskirts of a blue dwarf galaxy. The optical and
X-ray afterglow properties 34 h after the GRB are reminiscent of the afterglows
of long GRBs, which are attributable to synchrotron emission from
ultrarelativistic ejecta. We did not, however, detect a supernova, as found in
most nearby long GRB afterglows, which suggests a different origin for the
short GRBs.Comment: 11 pages, 3 figures, press material at http://www.astro.ku.dk/dark
Revision of the " Chloritisdelibrata (Benson, 1836)" group (Gastropoda, Stylommatophora, Camaenidae).
Chloritisdelibrata (Benson, 1836), known from northeastern India, was believed to have three varietal forms, sometimes mentioned as subspecies: C.delibratavar.khasiensis (Nevill, 1877) and C.delibratavar.fasciata (Godwin-Austen, 1875) from the Khasi Hills, India, and C.delibratavar.procumbens (Gould, 1844) from Dawei in Myanmar. The reproductive anatomy of the latter form is known and does not match with those of any continental camaenid genera, but does with that of the newly examined Chloritisplatytropis Möllendorff, 1894 from Thailand. The latter species is conchologically similar to Bouchetcamaenahuberi Thach, 2018 (synonym of Helixfouresi Morlet, 1886), which is the type species of the genus Bouchetcamaena Thach, 2018. Thus, Bouchetcamaena can provisionally host the entire Chloritisdelibrata -group with the exception of var. fasciata, which is transferred to Burmochloritis Godwin-Austen, 1920 due to the multiple reddish bands on its shell. The examination of shells deposited in the Natural History Museum, London revealed that seven morphologically distinguishable forms are present, which are accepted here as representing distinct species. Four new species are described from India: Bouchetcamaenafoveata Páll-Gergely sp. nov., B.fusca Páll-Gergely sp. nov., B.raripila Páll-Gergely sp. nov., and B.subdelibrata Páll-Gergely sp. nov
Primary care obesity management in Hungary: evaluation of the knowledge, practice and attitudes of family physicians
BACKGROUND: Obesity, a threatening pandemic, has an important public health implication. Before proper medication is available, primary care providers will have a distinguished role in prevention and management. Their performance may be influenced by many factors but their personal motivation is still an under-researched area. METHOD: The knowledge, attitudes and practice were reviewed in this questionnaire study involving a representative sample of 10% of all Hungarian family physicians. In different settings, 521 practitioners (448 GPs and 73 residents/vocational trainees) were questioned using a validated questionnaire. RESULTS: The knowledge about multimorbidity, a main consequence of obesity, was balanced.Only 51% of the GPs were aware of the diagnostic threshold for obesity; awareness being higher in cities (60%) and the highest among residents (90%). They also considered obesity an illness rather than an aesthetic issue.There were wider differences regarding attitudes and practice, influenced by the the doctors' age, gender, known BMI, previous qualification, less by working location.GPs with qualification in family medicine alone considered obesity management as higher professional satisfaction, compared to physicians who had previously other board qualification (77%vs68%). They measured their patients' waist circumference and waist/hip ratio (72%vs62%) more frequently, provided the obese with dietary advice more often, while this service was less frequent among capital-based doctors who accepted the self-reported body weight dates by patients more frequently / commonly. Similar reduced activity and weight-measurement in outdoor clothing were more typical among older doctors.Diagnosis based on BMI alone was the highest in cities (85%). Consultations were significantly shorter in practices with a higher number of enrolled patients and were longer by female providers who consulted longer with patients about the suspected causes of developing obesity (65%vs44%) and offered dietary records for patients significantly more frequently (65%vs52%). Most of the younger doctors agreed that obesity management was a primary care issue.Doctors in the normal BMI range were unanimous that they should be a model for their patients (94%vs81%). CONCLUSION: More education of primary care physicians, available practical guidelines and higher community involvement are needed to improve the obesity management in Hungary
Organization and Biology of the Porcine Serum Amyloid A (SAA) Gene Cluster: Isoform Specific Responses to Bacterial Infection.
Serum amyloid A (SAA) is a prominent acute phase protein. Although its biological functions are debated, the wide species distribution of highly homologous SAA proteins and their uniform behavior in response to injury or inflammation in itself suggests a significant role for this protein. The pig is increasingly being used as a model for the study of inflammatory reactions, yet only little is known about how specific SAA genes are regulated in the pig during acute phase responses and other responses induced by pro-inflammatory host mediators. We designed SAA gene specific primers and quantified the gene expression of porcine SAA1, SAA2, SAA3, and SAA4 by reverse transcriptase quantitative polymerase chain reaction (RT-qPCR) in liver, spleen, and lung tissue from pigs experimentally infected with the Gram-negative swine specific bacterium Actinobacillus pleuropneumoniae, as well as from pigs experimentally infected with the Gram-positive bacterium Staphylococcus aureus. Our results show that: 1) SAA1 may be a pseudogene in pigs; 2) we were able to detect two previously uncharacterized SAA transcripts, namely SAA2 and SAA4, of which the SAA2 transcript is primarily induced in the liver during acute infection and presumably contributes to circulating SAA in pigs; 3) Porcine SAA3 transcription is induced both hepatically and extrahepatically during acute infection, and may be correlated to local organ affection; 4) Hepatic transcription of SAA4 is markedly induced in pigs infected with A. pleuropneumoniae, but only weakly in pigs infected with S. aureus. These results for the first time establish the infection response patterns of the four porcine SAA genes which will be of importance for the use of the pig as a model for human inflammatory responses, e.g. within sepsis, cancer, and obesity research
The environmental history of Fenékpuszta with a special attention to the climate and precipitation of the last 2000 years
May Measurement Month 2018: a pragmatic global screening campaign to raise awareness of blood pressure by the International Society of Hypertension
Aims
Raised blood pressure (BP) is the biggest contributor to mortality and disease burden worldwide and fewer than half of those with hypertension are aware of it. May Measurement Month (MMM) is a global campaign set up in 2017, to raise awareness of high BP and as a pragmatic solution to a lack of formal screening worldwide. The 2018 campaign was expanded, aiming to include more participants and countries.
Methods and results
Eighty-nine countries participated in MMM 2018. Volunteers (≥18 years) were recruited through opportunistic sampling at a variety of screening sites. Each participant had three BP measurements and completed a questionnaire on demographic, lifestyle, and environmental factors. Hypertension was defined as a systolic BP ≥140 mmHg or diastolic BP ≥90 mmHg, or taking antihypertensive medication. In total, 74.9% of screenees provided three BP readings. Multiple imputation using chained equations was used to impute missing readings. 1 504 963 individuals (mean age 45.3 years; 52.4% female) were screened. After multiple imputation, 502 079 (33.4%) individuals had hypertension, of whom 59.5% were aware of their diagnosis and 55.3% were taking antihypertensive medication. Of those on medication, 60.0% were controlled and of all hypertensives, 33.2% were controlled. We detected 224 285 individuals with untreated hypertension and 111 214 individuals with inadequately treated (systolic BP ≥ 140 mmHg or diastolic BP ≥ 90 mmHg) hypertension.
Conclusion
May Measurement Month expanded significantly compared with 2017, including more participants in more countries. The campaign identified over 335 000 adults with untreated or inadequately treated hypertension. In the absence of systematic screening programmes, MMM was effective at raising awareness at least among these individuals at risk
Path-accelerated molecular dynamics: Parallel-in-time integration using path integrals
Massively parallel computer architectures create new opportunities for the
performance of long-timescale molecular dynamics (MD) simulations. Here, we
introduce the path-accelerated molecular dynamics (PAMD) method that takes
advantage of distributed computing to reduce the wall-clock time of MD
simulation via parallelization with respect to MD timesteps. The marginal
distribution for the time evolution of a system is expressed in terms of a path
integral, enabling the use of path sampling techniques to numerically integrate
MD trajectories. By parallelizing the evaluation of the path action with
respect to time and by initializing the path configurations from a
non-equilibrium distribution, the algorithm enables significant speedups in
terms of the length of MD trajectories that can be integrated in a given amount
of wall-clock time. The method is demonstrated for Brownian dynamics, although
it is generalizable to other stochastic equations of motion including open
systems. We apply the method to two simple systems, a harmonic oscillator and a
Lennard-Jones liquid, and we show that in comparison to the conventional Euler
integration scheme for Brownian dynamics, the new method can reduce the
wall-clock time for integrating trajectories of a given length by more than
three orders of magnitude in the former system and more than two in the latter.
This new method for parallelizing MD in the dimension of time can be trivially
combined with algorithms for parallelizing the MD force evaluation to achieve
further speedup
Welding dynamics in an atomistic model of an amorphous polymer blend with polymer-polymer interface
We consider an atomistic model of thermal welding at the polymer-polymer interface of a polyetherimide/polycarbonate blend, motivated by applications to 3D manufacturing in space. We follow diffusion of semiflexible chains at the interface and analyze strengthening of the samples as a function of the welding time tw by simulating the strain-stress and shear viscosity curves. The time scales for initial wetting, and for fast and slow diffusion, are revealed. It is shown that each component of the polymer blend has its own characteristic time of slow diffusion at the interface. Analysis of strainstress demonstrates saturation of the Young’s modulus at tw = 240 ns, while the tensile strength continues to increase. The shear viscosity is found to have a very weak dependence on the welding time for tw > 60 ns. It is shown that both strain-stress and shear viscosity curves agree with experimental data
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