1,358 research outputs found
Radial Velocities of Newly Discovered Globular Clusters in NGC 5128
We present radial velocity measurements for 74 globular clusters (GCs) in the
nearby giant elliptical NGC 5128, of which 31 are newly discovered clusters.
All the GC candidates were taken from the list of possible new clusters given
in the Harris, Harris, & Geisler (2004) photometric survey. In addition to the
newly confirmed clusters, we identified 24 definite foreground stars and 31
probable background galaxies. From a combined list of 299 known GCs in NGC 5128
with measured radial velocities and metallicity-sensitive (C - T_1) photometric
indices, we construct a new metallicity distribution function (MDF) for the
cluster system. The MDF shows an approximately bimodal form, with centroids at
[Fe/H] = -1.46 and -0.53, and with nearly equal numbers of metal-poor and
metal-rich clusters in the two modes. However, there are many
intermediate-color clusters in the distribution, and the fainter clusters tend
to have a higher proportion of red clusters. These features of the MDF may
indicate a widespread age range within the cluster system as well as an
intrinsically broad metallicity spread.Comment: 10 pages, 7 figures, 4 tables - accepted in Astronomical Journa
A cross-sectional study of predatory publishing emails received by career development grant awardees
OBJECTIVE:
To investigate the scope of academic spam emails (ASEs) among career development grant awardees and the factors associated with the amount of time spent addressing them.
DESIGN:
A cross-sectional survey of career development grant investigators via an anonymous online survey was conducted. In addition to demographic and professional information, we asked investigators to report the number of ASEs received each day, how they determined whether these emails were spam and time they spent per day addressing them. We used bivariate analysis to assess factors associated with the amount of time spent on ASEs.
SETTING:
An online survey sent via email on three separate occasions between November and December 2016.
PARTICIPANTS:
All National Institutes of Health career development awardees funded in the 2015 fiscal year.
MAIN OUTCOME MEASURES:
Factors associated with the amount of time spent addressing ASEs.
RESULTS:
A total of 3492 surveys were emailed, of which 206 (5.9%) were returned as undeliverable and 96 (2.7%) reported an out-of-office message; our overall response rate was 22.3% (n=733). All respondents reported receiving ASEs, with the majority (54.4%) receiving between 1 and 10 per day and spending between 1 and 10âmin each day evaluating them. The amount of time respondents reported spending on ASEs was associated with the number of peer-reviewed journal articles authored (p<0.001), a history of publishing in open access format (p<0.01), the total number of ASEs received (p<0.001) and a feeling of having missed opportunities due to ignoring these emails (p=0.04).
CONCLUSIONS:
ASEs are a common distraction for career development grantees that may impact faculty productivity. There is an urgent need to mitigate this growing problem
Serum, urinary, and salivary nitric oxide in rheumatoid arthritis: complexities of interpreting nitric oxide measures
Nitric oxide (NO) may play important roles in rheumatoid arthritis (RA). RA is an inflammatory disease involving joints and other systems including salivary glands. To assess NO production in RA patients, we compared levels of serum, urine, and salivary nitrite and nitrate (NOx) in patients with RA and normal subjects, and we examined the relationships of these measures to disease activity. Serum, urine, and NOx levels as well as renal creatinine, NOx clearance and fractional excretion rates were compared in 25 RA patients and 20 age- and gender-matched healthy controls. Subjects were hospitalized for 3 days and placed on a NOxrestricted diet. NOx was assayed using nitrate reductase and the Griess reagent. RA activity was assessed using standard clinical and laboratory measures. While consuming a restricted diet for 3 days to eliminate the effects of oral intake of NOx, 24 hour urinary NOx excretion decreased in both RA patients and healthy controls. Urine NOx levels at all time points were not significantly different between RA patients and normal subjects. Serum NOx levels also decreased during the 3 days of NOx restriction, but RA patients had higher serum NOx levels at all time points compared with the control group. Likewise, serum NOx/creatinine ratios were higher in RA patients than in controls. Although basal salivary flow rate and tear flow were lower in RA patients, salivary NOx levels did not differ between normal and RA subjects. While renal creatinine clearance was not different between the two groups, we found that RA patients had lower renal NOx clearance and lower renal NOx fractional excretion. After correction of p values for multiple comparisons, there were no significant relationships for the RA group between measures of disease activity and the urinary NOx, serum NOx, or urinary NOx clearance. Despite interest in the use of NO as a marker of disease activity, alterations in renal NOx clearance and fractional excretion in RA make it difficult to assess in vivo NO production even with strict dietary restriction of NOx intake
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Neuropsychological Test Performance in African-American and White Patients with Alzheimer's Disease
Little information exists on the performance of black versus white patients with Alzheimer's disease on neuropsychological tests for dementia.In this study, we compared performance on the CERAD (Consortium to Establish a Registry for Alzheimer's Disease) neuropsychological battery between white (n equals 830) and black (n equals 158) patients with Alzheimer's disease enrolled in the CERAD study at 23 university medical centers in the United States. The black patients were older, had fewer years of formal education, and were more impaired in their activities of daily living than were the white patients. After controlling for these characteristics and for duration of the disease and severity of dementia, there were differences in the performance of black and white patients on several of the cognitive measures. Black patients scored lower than whites on tests of visual naming and constructional praxis and on the Mini-Mental State Examination. There were no statistical differences in performance on tests of fluency and word list memory. These findings suggest that cultural or experiential differences may modify performance on specific neuropsychological tests. These factors, in addition to age and educational background, should be considered when interpreting performance on neuropsychological tests in elderly black patients with dementia
A checklist for clinical trials in rare disease: Obstacles and anticipatory actions-lessons learned from the FOR-DMD trial
Background: Trials in rare diseases have many challenges, among which are the need to set up multiple sites in different countries to achieve recruitment targets and the divergent landscape of clinical trial regulations in those countries. Over the past years, there have been initiatives to facilitate the process of international study set-up, but the fruits of these deliberations require time to be operationally in place. FOR-DMD (Finding the Optimum Steroid Regimen for Duchenne Muscular Dystrophy) is an academic-led clinical trial which aims to find the optimum steroid regimen for Duchenne muscular dystrophy, funded by the National Institutes of Health (NIH) for 5 years (July 2010 to June 2015), anticipating that all sites (40 across the USA, Canada, the UK, Germany and Italy) would be open to recruitment from July 2011. However, study start-up was significantly delayed and recruitment did not start until January 2013. Method: The FOR-DMD study is used as an example to identify systematic problems in the set-up of international, multi-centre clinical trials. The full timeline of the FOR-DMD study, from funding approval to site activation, was collated and reviewed. Systematic issues were identified and grouped into (1) study set-up, e.g. drug procurement; (2) country set-up, e.g. competent authority applications; and (3) site set-up, e.g. contracts, to identify the main causes of delay and suggest areas where anticipatory action could overcome these obstacles in future studies. Results: Time from the first contact to site activation across countries ranged from 6 to 24 months. Reasons of delay were universal (sponsor agreement, drug procurement, budgetary constraints), country specific (complexity and diversity of regulatory processes, indemnity requirements) and site specific (contracting and approvals). The main identified obstacles included (1) issues related to drug supply, (2) NIH requirements regarding contracting with non-US sites, (3) differing regulatory requirements in the five participating countries, (4) lack of national harmonisation with contracting and the requirement to negotiate terms and contract individually with each site and (5) diversity of languages needed for study materials. Additionally, as with many academic-led studies, the FOR-DMD study did not have access to the infrastructure and expertise that a contracted research organisation could provide, organisations often employed in pharmaceutical-sponsored studies. This delay impacted recruitment, challenged the clinical relevance of the study outcomes and potentially delayed the delivery of the best treatment to patients. Conclusion: Based on the FOR-DMD experience, and as an interim solution, we have devised a checklist of steps to not only anticipate and minimise delays in academic international trial initiation but also identify obstacles that will require a concerted effort on the part of many stakeholders to mitigate
Effects of 5-HT2C, 5-HT1A receptor challenges and modafinil on the initiation and persistence of gambling behaviours
Rationale Problematic patterns of gambling are characterised by loss of control and persistent gambling often to recover losses. However, little is known about the mechanisms that mediate initial choices to begin gambling and then continue to gamble in the face of losing outcomes. Objectives These experiments first assessed gambling and loss-chasing performance under different win/lose probabilities in C57Bl/6 mice, and then investigated the effects of antagonism of 5-HT2CR with SB242084, 5-HT1AR agonism with 8-OH-DPAT and modafinil, a putative cognitive enhancer. Results As seen in humans and other species, mice demonstrated the expected patterns of behaviour as the odds for winning were altered increasing gambling and loss-chasing when winning was more likely. SB242084 decreased the likelihood to initially gamble, but had no effects on subsequent gambling choices in the face of repeated losses. In contrast, 8-OH-DPAT had no effects on choosing to gamble in the first place, but once started 8-OH-DPAT increased gambling choices in a dose-sensitive manner. Modafinil effects were different to the serotonergic drugs in both decreasing the propensity to initiate gambling and chase losses. Conclusions We present evidence for dissociable effects of systemic drug administration on different aspects of gambling behaviour. These data extend and reinforce the importance of serotonergic mechanisms in mediating discrete components of gambling behaviour. They further demonstrate the ability of modafinil to reduce gambling behaviour. Our work using a novel mouse paradigm may be of utility in modelling the complex psychological and neurobiological underpinnings of gambling problems, including the analysis of genetic and environmental factors
Vaccination Rates and Family Barriers Among Children with Inflammatory Bowel Disease
Background: Many children with inflammatory bowel disease (IBD) are taking immunosuppressant medications that place them at risk for vaccine preventable diseases. Despite national guidelines, children with IBD have low vaccination rates. Adult data suggest that there is concern about the safety of vaccines. There are no current studies addressing perceived safety about vaccinations among families of children with IBD.
Methods: A total of 108 caregivers of children (ages 10-25 years) were surveyed during their outpatient visit, with approximately half having a diagnosis of IBD. The survey consisted of validated questions regarding vaccine safety and opinions. After enrollment, state-wide vaccine registry data was collected. Demographics between the two groups were compared using Ch-square and the Wilcoxon rank-sum tests to analyze Likert scale questions.
Results: The majority of children followed for IBD were Caucasian males, had Crohn's disease (68%) and were immunosuppressed. Results from the survey revealed a concern about vaccine safety (40% vs. 16%, p=0.03) and overall effectiveness (34% vs. 12%, p<0.01) in the IBD group compared to the non-IBD. Furthermore, more IBD families were worried that vaccines would worsen their child's symptoms (36% vs. 10%, p=<0.01). The majority of children were missing the flu and/or HPV vaccine. Finally, 96% of the children on a biologic for their IBD were missing the PPSV23 booster.
Conclusions: Caregivers of children with IBD are more concerned about vaccine safety and effectiveness than those with non-IBD diagnosis. Despite being on immunosuppressant medications, many patients were missing recommended vaccines
Synchronous deficits in cumulative muscle protein synthesis and ribosomal biogenesis underlie age-related anabolic resistance to exercise in humans
Ageing is associated with impaired hypertrophic responses to resistance exercise training (RET). Here we investigated the aetiology of âanabolic resistanceâ in older humans. Twenty healthy male individuals, 10 younger (Y; 23 ± 1 years) and 10 older (O; 69 ± 3 years), performed 6 weeks unilateral RET (6 Ă 8 repetitions, 75% of one repetition maximum (1-RM), 3 times per week). After baseline bilateral vastus lateralis (VL) muscle biopsies, subjects consumed 150 ml D2O (70 atom%; thereafter 50 ml weekâ1), further bilateral VL muscle biopsies were taken at 3 and 6 weeks to quantify muscle protein synthesis (MPS) via gas chromatographyâpyrolysisâisotope ratio mass spectrometry. After RET, 1-RM increased in Y (+35 ± 4%) and O (+25 ± 3%; P < 0.01), while MVC increased in Y (+21 ± 5%; P < 0.01) but not O (+6 ± 3%; not significant (NS)). In comparison to Y, O displayed blunted RET-induced increases in muscle thickness (at 3 and 6 weeks, respectively, Y: +8 ± 1% and +11 ± 2%, P < 0.01; O: +2.6 ± 1% and +3.5 ± 2%, NS). While âbasalâ longer term MPS was identical between Y and O (âŒ1.35 ± 0.1% dayâ1), MPS increased in response to RET only in Y (3 weeks, Y: 1.61 ± 0.1% dayâ1; O: 1.49 ± 0.1% dayâ1). Consistent with this, O exhibited inferior ribosomal biogenesis (RNA:DNA ratio and c-MYC induction: Y: +4 ± 2 fold change; O: +1.9 ± 1 fold change), translational efficiency (S6K1 phosphorylation, Y: +10 ± 4 fold change; O: +4 ± 2 fold change) and anabolic hormone milieu (testosterone, Y: 367 ± 19; O: 274 ± 19 ng dlâ1 (all P < 0.05). Anabolic resistance is thus multifactorial
Relationships between plant traits, soil properties and carbon fluxes differ between monocultures and mixed communities in temperate grassland
1. The use of plant traits to predict ecosystem functions has been gaining growing attention. Aboveâground plant traits, such as leaf nitrogen (N) content and specific leaf area (SLA), have been shown to strongly relate to ecosystem productivity, respiration and nutrient cycling. Furthermore, increasing plant functional trait diversity has been suggested as a possible mechanism to increase ecosystem carbon (C) storage. However, it is uncertain whether belowâground plant traits can be predicted by aboveâground traits, and if both aboveâ and belowâground traits can be used to predict soil properties and ecosystemâlevel functions.
2. Here, we used two adjacent field experiments in temperate grassland to investigate if aboveâ and belowâground plant traits are related, and whether relationships between plant traits, soil properties and ecosystem C fluxes (i.e. ecosystem respiration and net ecosystem exchange) measured in potted monocultures could be detected in mixed field communities.
3. We found that certain shoot traits (e.g. shoot N and C, and leaf dry matter content) were related to root traits (e.g. root N, root C:N and root dry matter content) in monocultures, but such relationships were either weak or not detected in mixed communities. Some relationships between plant traits (i.e. shoot N, root N and/or shoot C:N) and soil properties (i.e. inorganic N availability and microbial community structure) were similar in monocultures and mixed communities, but they were more strongly linked to shoot traits in monocultures and root traits in mixed communities. Structural equation modelling showed that aboveâ and belowâground traits and soil properties improved predictions of ecosystem C fluxes in monocultures, but not in mixed communities on the basis of communityâweighted mean traits.
4. Synthesis. Our results from a single grassland habitat detected relationships in monocultures between aboveâ and belowâground plant traits, and between plant traits, soil properties and ecosystem C fluxes. However, these relationships were generally weaker or different in mixed communities. Our results demonstrate that while plant traits can be used to predict certain soil properties and ecosystem functions in monocultures, they are less effective for predicting how changes in plant species composition influence ecosystem functions in mixed communities
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