1,278 research outputs found
Fire impacts recruitment more than survival of small-mammals in a tropical savanna
The frequency and spatial patterning of fire for optimal biodiversity conservation is often poorly understood by managers, in part due to a lack of understanding of the mechanisms responsible for altering population dynamics of individual species. We investigated changes in the vital rates (survival and recruitment) of four small mammal species (three marsupials and one rodent) in a tropical savanna under four different experimental fire treatments applied at a landscape scale. Apparent survival declined in all fire treatments for only one of four small mammal species (northern brown bandicoot Isoodon macrourus). Recruitment was reduced in three of four species in multiple fire treatments. The suppression of recruitment in the northern brown bandicoot and the brushtail possum Trichosurus vulpecula populations was greatest immediately after the initial fire treatment was applied, compared to remaining treatment applications in successive years, possibly due to an elevated fire intensity as a result of higher initial fuel loads. The results suggest that higher intensity fire impacted recruitment more than survival for small mammals at this site. To assist fire managers to conserve small mammal populations in tropical savannas, we recommend fire regimes that optimise habitat resources for recruitment. This may be achieved by a reduction in fire frequency and managing fuel loads to prevent an increase in fire intensity
The Application of a Hypothesis-driven Strategy to the Sensitive Detection and Location of Acetylated Lysine Residues
The application of a hypothesis-driven method for the sensitive determination of lysine acetylation sites on enzymatically digested proteins is described. Comparative sensitivity tests were carried out using serial dilution of an acetylated bovine serum albumin (AcBSA) digest to assess the performance of a multiple reaction monitoring (MRM)–based approach as compared to a more conventional precursor scanning (PS) method. Both methods were capable of selectively detecting an acetylated peptide at the low femtomole level when spiked into a background of 500 fmol six-protein tryptic digest. The MRM approach was roughly tenfold more sensitive than precursor scanning with one acetylated peptide detected and sequenced at the level of 2 fmol on-column. The technique was subsequently applied to a gel-derived sample of cytokeratin-8 (CK8) shown to contain acetylated lysine residues by Western blot analysis. The strategy applied herein, termed MRM-initiated detection and sequencing (MIDAS), resulted in the facile identification of novel sites of acetylation on this protein
An exploratory study of the association between online gaming addiction and enjoyment motivations for playing massively multiplayer online role-playing games
Massively multiplayer online role-playing games (MMORPGs) are a popular form of entertainment used by millions of gamers worldwide. Potential problems relating to MMORPG play have emerged, particularly in relation to being addicted to playing in such virtual environments. In the present study, factors relating to online gaming addiction and motivations for playing in MMORPGs were examined to establish whether they were associated with addiction. A sample comprised 1167 gamers who were surveyed about their gaming motivations. Latent Class Analysis revealed seven classes of motivations for playing MMORPGs, which comprised: (1) novelty; (2) highly social and discovery-orientated; (3) aggressive, anti-social and non-curious; (4) highly social, competitive; (5) low intensity enjoyment; (6) discovery-orientated; and (7) social classes. Five classes of gaming addiction-related experiences were extracted including: (1) high risk of addiction, (2) time-affected, (3) intermediate risk of addiction, (4) emotional control, and (5) low risk of addiction classes. Gender was a significant predictor of intermediate risk of addiction and emotional control class membership. Membership of the high risk of addiction class was significantly predicted by belonging to a highly social and competitive class, a novelty class, or an aggressive, anti-social, and non-curious class. Implications of these findings for assessment and treatment of MMORPG addiction are discussed
Medical causes of admissions to hospital among adults in Africa: a systematic review.
BACKGROUND: Despite the publication of several studies on the subject, there is significant uncertainty regarding the burden of disease among adults in sub-Saharan Africa (sSA). OBJECTIVES: To describe the breadth of available data regarding causes of admission to hospital, to systematically analyze the methodological quality of these studies, and to provide recommendations for future research. DESIGN: We performed a systematic online and hand-based search for articles describing patterns of medical illnesses in patients admitted to hospitals in sSA between 1950 and 2010. Diseases were grouped into bodily systems using International Classification of Disease (ICD) guidelines. We compared the proportions of admissions and deaths by diagnostic category using χ2. RESULTS: Thirty articles, describing 86,307 admissions and 9,695 deaths, met the inclusion criteria. The leading causes of admission were infectious and parasitic diseases (19.8%, 95% confidence interval [CI] 19.6-20.1), respiratory (16.2%, 95% CI 16.0-16.5) and circulatory (11.3%, 95% CI 11.1-11.5) illnesses. The leading causes of death were infectious and parasitic (17.1%, 95% CI 16.4-17.9), circulatory (16%, 95% CI 15.3-16.8) and digestive (16.2%, 95% CI 15.4-16.9). Circulatory diseases increased from 3.9% of all admissions in 1950-59 to 19.9% in 2000-2010 (RR 5.1, 95% CI 4.5-5.8, test for trend p<0.00005). The most prevalent methodological deficiencies, present in two-thirds of studies, were failures to use standardized case definitions and ICD guidelines for classifying illnesses. CONCLUSIONS: Cardiovascular and infectious diseases are currently the leading causes of admissions and in-hospital deaths in sSA. Methodological deficiencies have limited the usefulness of previous studies in defining national patterns of disease in adults. As African countries pass through demographic and health transition, they need to significantly invest in clinical research capacity to provide an accurate description of the disease burden among adults for public health policy
Analysis of the recombination landscape of hexaploid bread wheat reveals genes controlling recombination and gene conversion frequency
Background: Sequence exchange between homologous chromosomes through crossing over and gene conversion is highly conserved among eukaryotes, contributing to genome stability and genetic diversity. A lack of recombination limits breeding efforts in crops; therefore, increasing recombination rates can reduce linkage drag and generate new genetic combinations. Results: We use computational analysis of 13 recombinant inbred mapping populations to assess crossover and gene conversion frequency in the hexaploid genome of wheat (Triticum aestivum). We observe that high-frequency crossover sites are shared between populations and that closely related parents lead to populations with more similar crossover patterns. We demonstrate that gene conversion is more prevalent and covers more of the genome in wheat than in other plants, making it a critical process in the generation of new haplotypes, particularly in centromeric regions where crossovers are rare. We identify quantitative trait loci for altered gene conversion and crossover frequency and confirm functionality for a novel RecQ helicase gene that belongs to an ancient clade that is missing in some plant lineages including Arabidopsis. Conclusions: This is the first gene to be demonstrated to be involved in gene conversion in wheat. Harnessing the RecQ helicase has the potential to break linkage drag utilizing widespread gene conversions
Experimental realisation of Shor's quantum factoring algorithm using qubit recycling
Quantum computational algorithms exploit quantum mechanics to solve problems
exponentially faster than the best classical algorithms. Shor's quantum
algorithm for fast number factoring is a key example and the prime motivator in
the international effort to realise a quantum computer. However, due to the
substantial resource requirement, to date, there have been only four
small-scale demonstrations. Here we address this resource demand and
demonstrate a scalable version of Shor's algorithm in which the n qubit control
register is replaced by a single qubit that is recycled n times: the total
number of qubits is one third of that required in the standard protocol.
Encoding the work register in higher-dimensional states, we implement a
two-photon compiled algorithm to factor N=21. The algorithmic output is
distinguishable from noise, in contrast to previous demonstrations. These
results point to larger-scale implementations of Shor's algorithm by harnessing
scalable resource reductions applicable to all physical architectures.Comment: 7 pages, 3 figure
LC-MS/MS quantification of salvinorin A from biological fluids
A facile method for quantifying the concentration of the powerful and widely available hallucinogen salvinorin A (a selective kappa opioid agonist) from non-human primate cerebrospinal fluid (CSF) and human plasma has been developed using liquid chromatography-tandem mass spectrometry (LC-MS/MS) in positive electrospray ionization (ESI) mode. With CSF solid phase extraction can be avoided completely by simply diluting each sample to 10 % (v/v) acetonitrile, 1 % (v/v) formic acid and injecting under high aqueous conditions for analyte focusing. Extensive plasma sample preparation was investigated including protein precipitation, SPE column selection, and plasma particulate removal. Human plasma samples were centrifuged at 21,000 × gravity for 4 minutes to obtain clear particulate-free plasma, from which 300 μl was spiked with internal standard and loaded onto a C18 SPE column with a 100 mg mL−1 loading capacity. Guard columns (C18, hand packed 1 mm × 20 mm) were exchanged after backpressure increased above 4600psi, about 250 injections. A shallow acetonitrile/water gradient was used, 29 to 33% CH3CN over 8 minutes to elute salvinorin A. Reduction of chemical noise was achieved using tandem mass spectrometry with multiple reaction monitoring while sensitivity increases were observed using a 50 μL injection volume onto a small bore analytical column (C18, 1 mm ID × 50 mm) thus increasing peak concentration. Limits of quantification were found to be 0.0125 ng mL−1 (CSF) and 0.05 ng mL−1 (plasma) with interday precision and accuracy below 1.7 % and 9.42 % (CSF) and 3.47 % and 12.37 % (plasma) respectively. This method was used to determine the concentration of salvinorin A from an in vivo Rhesus monkey study and a trial of healthy human research participants, using behaviorally active doses
Prion protein interacts with bace1 and differentially regulates its activity towards wild type and swedish mutant amyloid precursor protein
In Alzheimer disease amyloid-β (Aβ) peptides derived from the amyloid precursor protein (APP) accumulate in the brain. Cleavage of APP by the β-secretase BACE1 is the rate-limiting step in the production of Aβ. We have reported previously that the cellular prion protein (PrP(C)) inhibited the action of BACE1 toward human wild type APP (APP(WT)) in cellular models and that the levels of endogenous murine Aβ were significantly increased in PrP(C)-null mouse brain. Here we investigated the molecular and cellular mechanisms underlying this observation. PrP(C) interacted directly with the prodomain of the immature Golgi-localized form of BACE1. This interaction decreased BACE1 at the cell surface and in endosomes where it preferentially cleaves APP(WT) but increased it in the Golgi where it preferentially cleaves APP with the Swedish mutation (APP(Swe)). In transgenic mice expressing human APP with the Swedish and Indiana familial mutations (APP(Swe,Ind)), PrP(C) deletion had no influence on APP proteolytic processing, Aβ plaque deposition, or levels of soluble Aβ or Aβ oligomers. In cells, although PrP(C) inhibited the action of BACE1 on APP(WT), it did not inhibit BACE1 activity toward APP(Swe). The differential subcellular location of the BACE1 cleavage of APP(Swe) relative to APP(WT) provides an explanation for the failure of PrP(C) deletion to affect Aβ accumulation in APP(Swe,Ind) mice. Thus, although PrP(C) exerts no control on cleavage of APP(Swe) by BACE1, it has a profound influence on the cleavage of APP(WT), suggesting that PrP(C) may be a key protective player against sporadic Alzheimer disease
Learning to prescribe - pharmacists' experiences of supplementary prescribing training in England
Background: The introduction of non-medical prescribing for professions such as pharmacy and nursing in
recent years offers additional responsibilities and opportunities but attendant training issues. In the UK and in contrast to some international models, becoming a non-medical prescriber involves the completion of an
accredited training course offered by many higher education institutions, where the skills and knowledge
necessary for prescribing are learnt.
Aims: to explore pharmacists' perceptions and experiences of learning to prescribe on supplementary prescribing (SP) courses, particularly in relation to inter-professional learning, course content and subsequent use of prescribing in practice.
Methods: A postal questionnaire survey was sent to all 808 SP registered pharmacists in England in April 2007,
exploring demographic, training, prescribing, safety culture and general perceptions of SP.
Results: After one follow-up, 411 (51%) of pharmacists responded. 82% agreed SP training was useful, 58%
agreed courses provided appropriate knowledge and 62% agreed that the necessary prescribing skills were gained.
Clinical examination, consultation skills training and practical experience with doctors were valued highly;
pharmacology training and some aspects of course delivery were criticised. Mixed views on inter-professional
learning were reported – insights into other professions being valued but knowledge and skills differences
considered problematic. 67% believed SP and recent independent prescribing (IP) should be taught together, with more diagnostic training wanted; few pharmacists trained in IP, but many were training or intending to train. There was no association between pharmacists' attitudes towards prescribing training and when they undertook training between 2004 and 2007 but earlier cohorts were more likely to be using supplementary prescribing in practice.
Conclusion: Pharmacists appeared to value their SP training and suggested improvements that could inform
future courses. The benefits of inter-professional learning, however, may conflict with providing professionspecific training. SP training may be perceived to be an instrumental 'stepping stone' in pharmacists' professional project of gaining full IP status
Differential Drug Survival of Biologic Therapies for the Treatment of Psoriasis: A Prospective Observational Cohort Study from the British Association of Dermatologists Biologic Interventions Register (BADBIR)
Drug survival reflects a drug’s effectiveness, safety, and tolerability. We assessed the drug survival of biologics used to treat psoriasis in a prospective national pharmacovigilance cohort (British Association of Dermatologists Biologic Interventions Register (BADBIR)). The survival rates of the first course of biologics for 3,523 biologic-naive patients with chronic plaque psoriasis were compared using survival analysis techniques and predictors of discontinuation analyzed using a multivariate Cox proportional hazards model. Data for patients on adalimumab (n=1,879), etanercept (n=1,098), infliximab (n=96), and ustekinumab (n=450) were available. The overall survival rate in the first year was 77%, falling to 53% in the third year. Multivariate analysis showed that female gender (hazard ratio (HR) 1.22; 95% confidence interval (CI): 1.09–1.37), being a current smoker (HR 1.19; 95% CI: 1.03–1.38), and a higher baseline dermatology life quality index (HR 1.01; 95% CI: 1.00–1.02) were predictors of discontinuation. Presence of psoriatic arthritis (HR 0.82; 95% CI: 0.71–0.96) was a predictor for drug survival. As compared with adalimumab, patients on etanercept (HR 1.63; 95% CI: 1.45–1.84) or infliximab (HR 1.56; 95% CI: 1.16–2.09) were more likely to discontinue therapy, whereas patients on ustekinumab were more likely to persist (HR 0.48; 95% CI: 0.37–0.62). After accounting for relevant covariates, ustekinumab had the highest first-course drug survival. The results of this study will aid clinical decision making when choosing biologic therapy for psoriasis patients
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