Field evidence for the influence of weathering on rock erodibility and channel form in bedrock rivers

Erosion processes in bedrock-floored rivers shape channel cross-sectional geometry and the broader landscape. However, the influence of weathering on channel slope and geometry is not well understood. Weathering can produce variation in rock erodibility within channel cross-sections. Recent numerical modeling results suggest that weathering may preferentially weaken rock on channel banks relative to the thalweg, strongly influencing channel form. Here, we present the first quantitative field study of differential weathering across channel cross-sections. We hypothesize that average cross-section erosion rate controls the magnitude of this contrast in weathering between the banks and the thalweg. Erosion rate, in turn, is moderated by the extent to which weathering processes increase bedrock erodibility. We test these hypotheses on tributaries to the Potomac River, Virginia, with inferred erosion rates from similar to 0.1m/kyr to \u3e0.8m/kyr, with higher rates in knickpoints spawned by the migratory Great Falls knickzone. We selected nine channel cross-sections on three tributaries spanning the full range of erosion rates, and at multiple flow heights we measured (1) rock compressive strength using a Schmidt hammer, (2) rock surface roughness using a contour gage combined with automated photograph analysis, and (3) crack density (crack length/area) at three cross-sections on one channel. All cross-sections showed significant (

Why is cheating wrong?

Since cheating is obviously wrong, arguments against it (it provides an unfair advantage, it hinders learning) need only be mentioned in passing. But the argument of unfair advantage absurdly takes education to be essentially a race of all against all; moreover, it ignores that many cases of unfair (dis)advantages are widely accepted. That cheating can hamper learning does not mean that punishing cheating will necessarily favor learning, so that this argument does not obviously justify sanctioning cheaters. -- Keywords: academic dishonesty, academic integrity, academic misconduct, education, ethics, homework, plagiarismComment: 8 pages; new (completely rewritten) version; in Studies in Philosophy and Education (2009

Effectiveness of second-generation antipsychotics: a naturalistic, randomized comparison of olanzapine, quetiapine, risperidone, and ziprasidone

<p>Abstract</p> <p>Background</p> <p>No clear recommendations exist regarding which antipsychotic drug should be prescribed first for a patient suffering from psychosis. The primary aims of this naturalistic study were to assess the head-to-head effectiveness of first-line second-generation antipsychotics with regards to time until drug discontinuation, duration of index admission, time until readmission, change of psychopathology scores and tolerability outcomes.</p> <p>Methods</p> <p>Patients ≥ 18 years of age admitted to the emergency ward for symptoms of psychosis were consecutively randomized to risperidone (n = 53), olanzapine (n = 52), quetiapine (n = 50), or ziprasidone (n = 58), and followed for up to 2 years.</p> <p>Results</p> <p>A total of 213 patients were included, of which 68% were males. The sample represented a diverse population suffering from psychosis. At admittance the mean Positive and Negative Syndrome Scale (PANSS) total score was 74 points and 44% were antipsychotic drug naïve. The primary intention-to-treat analyses revealed no substantial differences between the drugs regarding the times until discontinuation of initial drug, until discharge from index admission, or until readmission. Quetiapine was superior to risperidone and olanzapine in reducing the PANSS total score and the positive subscore. Quetiapine was superior to the other drugs in decreasing the PANSS general psychopathology subscore; in decreasing the Clinical Global Impression - Severity of Illness scale score (CGI-S); and in increasing the Global Assessment of Functioning - Split version, Functions scale score (GAF-F). Ziprasidone was superior to risperidone in decreasing the PANSS positive symptoms subscore and the CGI-S score, and in increasing the GAF-F score. The drugs performed equally with regards to most tolerability outcomes except a higher increase of hip-circumference per day for olanzapine compared to risperidone, and more galactorrhoea for risperidone compared to the other groups.</p> <p>Conclusions</p> <p>Quetiapine appears to be a good starting drug candidate in this sample of patients admitted to hospital for symptoms of psychosis.</p> <p>Trial Registration</p> <p>ClinicalTrials.gov ID; URL: <url>http://www.clinicaltrials.gov/</url>: NCT00932529</p

First observations of separated atmospheric nu_mu and bar{nu-mu} events in the MINOS detector

The complete 5.4 kton MINOS far detector has been taking data since the beginning of August 2003 at a depth of 2070 meters water-equivalent in the Soudan mine, Minnesota. This paper presents the first MINOS observations of nuµ and [overline nu ]µ charged-current atmospheric neutrino interactions based on an exposure of 418 days. The ratio of upward- to downward-going events in the data is compared to the Monte Carlo expectation in the absence of neutrino oscillations, giving Rup/downdata/Rup/downMC=0.62-0.14+0.19(stat.)±0.02(sys.). An extended maximum likelihood analysis of the observed L/E distributions excludes the null hypothesis of no neutrino oscillations at the 98% confidence level. Using the curvature of the observed muons in the 1.3 T MINOS magnetic field nuµ and [overline nu ]µ interactions are separated. The ratio of [overline nu ]µ to nuµ events in the data is compared to the Monte Carlo expectation assuming neutrinos and antineutrinos oscillate in the same manner, giving R[overline nu ][sub mu]/nu[sub mu]data/R[overline nu ][sub mu]/nu[sub mu]MC=0.96-0.27+0.38(stat.)±0.15(sys.), where the errors are the statistical and systematic uncertainties. Although the statistics are limited, this is the first direct observation of atmospheric neutrino interactions separately for nuµ and [overline nu ]µ

Political leadership and the politics of performance:France, Syria and the chemical weapons crisis of 2013

This article draws upon developments in UK research on political rhetoric and political performance in order to examine the incident in 2013 when French President François Hollande committed French forces to a US-led punitive strike against Syria, after the use of chemical weapons in a Damascus suburb on 21 August. The US-led retaliation did not take place. This article analyses Hollande's declaration on 27 July and his TV appearance on 15 September. His rhetoric and style are best understood as generic to the nature of the presidential office of the Fifth Republic. The article concludes by appraising how analysis of the French case contributes to the developing literature on rhetoric, celebrity and performance

Selective enhancement of endothelial BMPR-II with BMP9 reverses pulmonary arterial hypertension.

Genetic evidence implicates the loss of bone morphogenetic protein type II receptor (BMPR-II) signaling in the endothelium as an initiating factor in pulmonary arterial hypertension (PAH). However, selective targeting of this signaling pathway using BMP ligands has not yet been explored as a therapeutic strategy. Here, we identify BMP9 as the preferred ligand for preventing apoptosis and enhancing monolayer integrity in both pulmonary arterial endothelial cells and blood outgrowth endothelial cells from subjects with PAH who bear mutations in the gene encoding BMPR-II, BMPR2. Mice bearing a heterozygous knock-in allele of a human BMPR2 mutation, R899X, which we generated as an animal model of PAH caused by BMPR-II deficiency, spontaneously developed PAH. Administration of BMP9 reversed established PAH in these mice, as well as in two other experimental PAH models, in which PAH develops in response to either monocrotaline or VEGF receptor inhibition combined with chronic hypoxia. These results demonstrate the promise of direct enhancement of endothelial BMP signaling as a new therapeutic strategy for PAH

Ventral and dorsal striatal dopamine efflux and behavior in rats with simple vs. co-morbid histories of cocaine sensitization and neonatal ventral hippocampal lesions

xposing animal models of mental illness to addictive drugs provides an approach to understanding the neural etiology of dual diagnosis disorders. Previous studies have shown that neonatal ventral hippocampal lesions (NVHL) in rats produce features of both schizophrenia and addiction vulnerability. Objective This study investigated ventral and dorsal striatal dopamine (DA) efflux in NVHL rats combined with behavioral sensitization to cocaine. Methods Adult NVHL vs. SHAM-operated rats underwent a 5-day injection series of cocaine (15 mg/kg/day) vs. saline. One week later, rats were cannulated in nucleus accumbens SHELL, CORE, or caudate–putamen. Another week later, in vivo microdialysis sampled DA during locomotor testing in which a single cocaine injection (15 mg/kg) was delivered. Results NVHLs and cocaine history significantly increased behavioral activation approximately 2-fold over SHAM-saline history rats. DA efflux curves corresponded time dependently with the cocaine injection and locomotor curves and varied significantly by striatal region: Baseline DA levels increased 5-fold while cocaine-stimulated DA efflux decreased by half across a ventral to dorsal striatal gradient. However, NVHLs, prior cocaine history, and individual differences in behavior were not underpinned by differential DA efflux overall or within any striatal region.Conclusion Differences in ventral/dorsal striatal DA efflux are not present in and are not required for producing differential levels of acute cocaine-induced behavioral activation in NVHLs with and without a behaviorally sensitizing cocaine history. These findings suggest other neurotransmitter systems, and alterations in striatal network function post-synaptic to DA transmission are more important to understanding the interactive effects of addictive drugs and mental illness

Suicide risk in schizophrenia: learning from the past to change the future

Suicide is a major cause of death among patients with schizophrenia. Research indicates that at least 5–13% of schizophrenic patients die by suicide, and it is likely that the higher end of range is the most accurate estimate. There is almost total agreement that the schizophrenic patient who is more likely to commit suicide is young, male, white and never married, with good premorbid function, post-psychotic depression and a history of substance abuse and suicide attempts. Hopelessness, social isolation, hospitalization, deteriorating health after a high level of premorbid functioning, recent loss or rejection, limited external support, and family stress or instability are risk factors for suicide in patients with schizophrenia. Suicidal schizophrenics usually fear further mental deterioration, and they experience either excessive treatment dependence or loss of faith in treatment. Awareness of illness has been reported as a major issue among suicidal schizophrenic patients, yet some researchers argue that insight into the illness does not increase suicide risk. Protective factors play also an important role in assessing suicide risk and should also be carefully evaluated. The neurobiological perspective offers a new approach for understanding self-destructive behavior among patients with schizophrenia and may improve the accuracy of screening schizophrenics for suicide. Although, there is general consensus on the risk factors, accurate knowledge as well as early recognition of patients at risk is still lacking in everyday clinical practice. Better knowledge may help clinicians and caretakers to implement preventive measures. This review paper is the results of a joint effort between researchers in the field of suicide in schizophrenia. Each expert provided a brief essay on one specific aspect of the problem. This is the first attempt to present a consensus report as well as the development of a set of guidelines for reducing suicide risk among schizophenia patients