6,043 research outputs found
Co-author weighting in bibliometric methodology and subfields of a scientific discipline
Collaborative work and co-authorship are fundamental to the advancement of
modern science. However, it is not clear how collaboration should be measured
in achievement-based metrics. Co-author weighted credit introduces distortions
into the bibliometric description of a discipline. It puts great weight on
collaboration - not based on the results of collaboration - but purely because
of the existence of collaborations. In terms of publication and citation
impact, it artificially favors some subdisciplines. In order to understand how
credit is given in a co-author weighted system (like the NRC's method), we
introduced credit spaces. We include a study of the discipline of physics to
illustrate the method. Indicators are introduced to measure the proportion of a
credit space awarded to a subfield or a set of authors.Comment: 11 pages, 1 figure, 4 table
Post-Election Audits: Restoring Trust in Elections
With the intention of assisting legislators, election officials and the public to make sense of recent literature on post-election audits and convert it into realistic audit practices, the Brennan Center and the Samuelson Law, Technology and Public Policy Clinic at Boalt Hall School of Law (University of California Berkeley) convened a blue ribbon panel (the "Audit Panel") of statisticians, voting experts, computer scientists and several of the nation's leading election officials. Following a review of the literature and extensive consultation with the Audit Panel, the Brennan Center and the Samuelson Clinic make several practical recommendations for improving post-election audits, regardless of the audit method that a jurisdiction ultimately decides to adopt
Hawkes process as a model of social interactions: a view on video dynamics
We study by computer simulation the "Hawkes process" that was proposed in a
recent paper by Crane and Sornette (Proc. Nat. Acad. Sci. USA 105, 15649
(2008)) as a plausible model for the dynamics of YouTube video viewing numbers.
We test the claims made there that robust identification is possible for
classes of dynamic response following activity bursts. Our simulated timeseries
for the Hawkes process indeed fall into the different categories predicted by
Crane and Sornette. However the Hawkes process gives a much narrower spread of
decay exponents than the YouTube data, suggesting limits to the universality of
the Hawkes-based analysis.Comment: Added errors to parameter estimates and further description. IOP
style, 13 pages, 5 figure
Wireless Integrated Microelectronic Vacuum Sensor System
NASA Stennis Space Center's (SSC's) large rocket engine test facility requires the use of liquid propellants, including the use of cryogenic fluids like liquid hydrogen as fuel, and liquid oxygen as an oxidizer (gases which have been liquefied at very low temperatures). These fluids require special handling, storage, and transfer technology. The biggest problem associated with transferring cryogenic liquids is product loss due to heat transfer. Vacuum jacketed piping is specifically designed to maintain high thermal efficiency so that cryogenic liquids can be transferred with minimal heat transfer. A vacuum jacketed pipe is essentially two pipes in one. There is an inner carrier pipe, in which the cryogenic liquid is actually transferred, and an outer jacket pipe that supports and seals the vacuum insulation, forming the "vacuum jacket." The integrity of the vacuum jacketed transmission lines that transfer the cryogenic fluid from delivery barges to the test stand must be maintained prior to and during engine testing. To monitor the vacuum in these vacuum jacketed transmission lines, vacuum gauge readings are used. At SSC, vacuum gauge measurements are done on a manual rotation basis with two technicians, each using a handheld instrument. Manual collection of vacuum data is labor intensive and uses valuable personnel time. Additionally, there are times when personnel cannot collect the data in a timely fashion (i.e., when a leak is detected, measurements must be taken more often). Additionally, distribution of this data to all interested parties can be cumbersome. To simplify the vacuum-gauge data collection process, automate the data collection, and decrease the labor costs associated with acquiring these measurements, an automated system that monitors the existing gauges was developed by Invocon, Inc. For this project, Invocon developed a Wireless Integrated Microelectronic Vacuum Sensor System (WIMVSS) that provides the ability to gather vacuum-gauge measurements automatically and wirelessly, in near-real time - using a low-maintenance, lowpower sensor mesh network. The WIMVSS operates by using a self-configuring mesh network of wireless sensor units. Mesh networking is a type of networking where each sensor or node can capture and disseminate its own data, but also serve as a relay to receive and transmit data from other sensors. Each sensor node can synchronize with adjacent sensors, and propagate data from one sensor to the next, until the destination is reached. In this case, the destination is a Network Interface Unit (NIU). The WIMVSS sensors are mounted on the existing vacuum gauges. Information gathered by the sensors is sent to the NIU. Because of the mesh networking, if a sensor cannot directly send the data to the NIU, it can be propagated through the network of sensors. The NIU requires antenna access to the sensor units, AC power, and an Ethernet connection. The NIU bridges the sensor network to a WIMVSS server via an Ethernet connection. The server is configured with a database, a Web server, and proprietary interface software that makes it possible for the vacuum measurements from vacuum jacketed fluid lines to be saved, retrieved, and then displayed from any Web-enabled PC that has access to the Internet. Authorized users can then simply access the data from any PC with Internet connection. Commands can also be sent directly from the Web interface for control and maintenance of the sensor network. The technology enabled by the WIMVSS decreases labor required for gathering vacuum measurements, increases access to vacuum data by making it available on any computer with access to the Internet, increases the frequency with which data points can be acquired for evaluating the system, and decreases the recurring cost of the sensors by using off-the-shelf components and integrating these with heritage vacuum gauges
Gender Specific Disruptions in Emotion Processing in Younger Adults with Depression
Background: One of the principal theories regarding the biological basis of major depressive disorder (MDD) implicates a dysregulation of emotion-processing circuitry. Gender differences in how emotions are processed and relative experience with emotion processing might help to explain some of the disparities in the prevalence of MDD between women and men. This study sought to explore how gender and depression status relate to emotion processing. Methods: This study employed a 2 (MDD status) × 2 (gender) factorial design to explore differences in classifications of posed facial emotional expressions (N=151). Results: For errors, there was an interaction between gender and depression status. Women with MDD made more errors than did nondepressed women and men with MDD, particularly for fearful and sad stimuli (Ps Ps P=.01). Men with MDD, conversely, performed similarly to control men (P=.61). Conclusions: These results provide novel and intriguing evidence that depression in younger adults (years) differentially disrupts emotion processing in women as compared to men. This interaction could be driven by neurobiological and social learning mechanisms, or interactions between them, and may underlie differences in the prevalence of depression in women and men. Depression and Anxiety, 2009. Published 2008 Wiley-Liss, Inc
Movement Intention Is Better Predicted than Attention in the Posterior Parietal Cortex
We decoded on a trial-by-trial basis the location of visual targets, as a marker of the locus of attention, and intentions to reach and to saccade in different directions using the activity of neurons in the posterior parietal cortex of two monkeys. Predictions of target locations were significantly worse than predictions of movement plans for the same target locations. Moreover, neural signals in the parietal reach region (PRR) gave better predictions of reaches than saccades, whereas signals in the lateral intraparietal area (LIP) gave better predictions of saccades than reaches. Taking together the activity of both areas, the prediction of either movement in all directions became nearly perfect. These results cannot be explained in terms of an attention effect and support the idea of two segregated populations in the posterior parietal cortex, PRR and LIP, that are involved in different movement plans
In-depth PtdIns(3,4,5)P3 signalosome analysis identifies DAPP1 as a negative regulator of GPVIdriven platelet function
Effect of Bromocriptine-QR (a Quick-Release Formulation of Bromocriptine Mesylate) on Major Adverse Cardiovascular Events in Type 2 Diabetes Subjects
Background: Bromocriptine-QR (a quick-release formulation of bromocriptine mesylate), a dopamine D2 receptor agonist, is a US Food and Drug Administrration–approved treatment for type 2 diabetes mellitus (T2DM). A 3070-subject randomized trial demonstrated a significant, 40% reduction in relative risk among bromocriptine-QR-treated subjects in a prespecified composite cardiovascular (CV) end point that included ischemic-related (myocardial infarction and stroke) and nonischemic-related (hospitalization for unstable angina, congestive heart failure [CHF], or revascularization surgery) end points, but did not include cardiovascular death as a component of this composite. The present investigation was undertaken to more critically evaluate the impact of bromocriptine-QR on cardiovascular outcomes in this study subject population by (1) including CV death in the above-described original composite analysis and then stratifying this new analysis on the basis of multiple demographic subgroups and (2) analyzing the influence of this intervention on only the “hard” CV end points of myocardial infarction, stroke, and CV death (major adverse cardiovascular events [MACEs]). Methods and Results: Three thousand seventy T2DM subjects on stable doses of ≤2 antidiabetes medications (including insulin) with HbA1c ≤10.0 (average baseline HbA1c=7.0) were randomized 2:1 to bromocriptine-QR (1.6 to 4.8 mg/day) or placebo for a 52-week treatment period. Subjects with heart failure (New York Heart Classes I and II) and precedent myocardial infarction or revascularization surgery were allowed to participate in the trial. Study outcomes included time to first event for each of the 2 CV composite end points described above. The relative risk comparing bromocriptine-QR with the control for the cardiovascular outcomes was estimated as a hazard ratio with 95% confidence interval on the basis of Cox proportional hazards regression. The statistical significance of any between-group difference in the cumulative percentage of CV events over time (derived from a Kaplan–Meier curve) was determined by a log-rank test on the intention-to-treat population. Study subjects were in reasonable metabolic control, with an average baseline HbA1c of 7.0±1.1, blood pressure of 128/76±14/9, and total and LDL cholesterol of 179±42 and 98±32, respectively, with 88%, 77%, and 69% of subjects being treated with antidiabetic, antihypertensive, and antihyperlipidemic agents, respectively. Ninety-one percent of the expected person-year outcome ascertainment was obtained in this study. Respecting the CV-inclusive composite cardiovascular end point, there were 39 events (1.9%) among 2054 bromocriptine-QR-treated subjects versus 33 events (3.2%) among 1016 placebo subjects, yielding a significant, 39% reduction in relative risk in this end point with bromocriptine-QR exposure (P=0.0346; log-rank test) that was not influenced by age, sex, race, body mass index, duration of diabetes, or preexisting cardiovascular disease. In addition, regarding the MACE end point, there were 14 events (0.7%) among 2054 bromocriptine-QR-treated subjects and 15 events (1.5%) among 1016 placebo-treated subjects, yielding a significant, 52% reduction in relative risk in this end point with bromocriptine-QR exposure (P<0.05; log-rank test). Conclusions: These findings reaffirm and extend the original observation of relative risk reduction in cardiovascular adverse events among type 2 diabetes subjects treated with bromocriptine-QR and suggest that further investigation into this impact of bromocriptine-QR is warranted
In-depth PtdIns(3,4,5)P3 signalosome analysis identifies DAPP1 as a negative regulator of GPVIdriven platelet function
A disorder of surfactant metabolism without identified genetic mutations
BACKGROUND:
Surfactant metabolism disorders may result in diffuse lung disease in children.
CASE PRESENTATION:
We report a 3-years-old boy with dry cough, progressive hypoxemia, dyspnea and bilateral ground glass opacities at chest high-resolution computed tomography (HRCT) who had no variants in genes encoding surfactant proteins or transcription factors. Lung histology strongly suggested an abnormality of surfactant protein. A 7-month course of pulse intravenous high-dose methylprednisolone plus oral hydroxychloroquine and azithromycin led to gradual weaning from oxygen and oral steroids, and to improvement of cough and dyspnea. Over the follow-up period, hydroxychloroquine and azithromycin were not withdrawn as cough and dyspnea re-appeared at each attempt and disappeared at re-start. At 6 years of age chest HRCT still appeared unchanged, but clinical symptoms or signs were absent.
CONCLUSIONS:
In children suspected of inborn errors of pulmonary surfactant metabolism who do not have a recognized genetic mutation, lung biopsy with consistent histology may help physicians to address the definitive diagnosis
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