814 research outputs found
Female scholars need to achieve more for equal public recognition
Different kinds of "gender gap" have been reported in different walks of the
scientific life, almost always favouring male scientists over females. In this
work, for the first time, we present a large-scale empirical analysis to ask
whether female scientists with the same level of scientific accomplishment are
as likely as males to be recognised. We particularly focus on Wikipedia, the
open online encyclopedia that its open nature allows us to have a proxy of
community recognition. We calculate the probability of appearing on Wikipedia
as a scientist for both male and female scholars in three different fields. We
find that women in Physics, Economics and Philosophy are considerable less
likely than men to be recognised on Wikipedia across all levels of achievement.Comment: Under revie
The nucleus retroambiguus control of respiration
The role of the nucleus retroambiguus (NRA) in the context of respiration control has been subject of debate for considerable time. To solve this problem, we chemically (using d, L-homocysteic acid) stimulated the NRA in unanesthetized precollicularly decerebrated cats and studied the respiratory effect via simultaneous measurement of tracheal pressure and electromyograms of diaphragm, internal intercostal (IIC), cricothyroid (CT), and external oblique abdominal (EO) muscles, NRA-stimulation 0-1 mm caudal to the obex resulted in recruitment of IIC muscle and reduction in respiratory frequency. NRA-stimulation 1-3 mm caudal to the obex produced vocalization along with CT activation and slight increase in tracheal pressure, but no change in respiratory frequency. NRA-stimulation 3-5 mm caudal to the obex produced CT muscle activation and an increase in respiratory frequency, but no vocalization. NRA-stimulation 5-8 mm caudal to the obex produced EO muscle activation and reduction in respiratory frequency. A change to the inspiratory effort was never observed, regardless of which NRA part was stimulated. The results demonstrate that NRA does not control eupneic inspiration but consists of topographically separate groups of premotor interneurons each producing detailed motor actions. These motor activities have in common that they require changes to eupneic breathing. Different combination of activation of these premotor neurons determines the final outcome, e.g., vocalization, vomiting, coughing, sneezing, mating posture, or child delivery. Higher brainstem regions such as the midbrain periaqueductal gray (PAG) decides which combination of NRA neurons are excited. In simple terms, the NRA is the piano, the PAG one of the piano players
A glycinergic projection from the ventromedial lower brainstem to spinal motoneurons. An ultrastructural double labeling study in rat
__Abstract__
In the present study it was determined whether glycine was present in the descending brainstem projections to spinal motoneurons in the rat. For this purpose injections of wheatgerm agglutinin-horseradish peroxidase (WGA-HRP) were made in the ventromedial part of the lower brainstem at the levels of the rostral inferior olive and the caudal facial nucleus. After perfusion, WGA-HRP histochemistry was performed, followed by the postembedding immunogold tehncque with an antbody against glycine. Electron microscopical examination of the lumbar motoneuronal cell groups showed that 15% of the WGA-HRP labeled terminals, derived from the ventromedial reticular formation, were also labeled for glycine. The majority (91%) of these double labeled terminal were of the F-type (containing many flattened vesicles), while the remaining 9% were of the S-type (containing mostly sphetical vesicles). Many of the double labeled terminals established a synapse, mostly with proximal and distal dendrites. The present data, combined with our previous findings that 40% of the projections from the same ventromedial brainstem area to lumbar motoneurons contained γ-aminobutyric acid (GABA), indicate that over 50% of these brainstem projections contain GABA and/or glycine, exerting a direct inhibition effect on spinal motoneurons. The possibility that the glycinergic fibers within these projections play an important role in producing muscle atonia during rapid eye movement (REM) sleep is discussed
KC-SMARTR: An R package for detection of statistically significant aberrations in multi-experiment aCGH data
Background: Most approaches used to find recurrent or differential DNA Copy Number Alterations (CNA) in array Comparative Genomic Hybridization (aCGH) data from groups of tumour samples depend on the discretization of the aCGH data to gain, loss or no-change states. This causes loss of valuable biological information in tumour samples, which are frequently heterogeneous. We have previously developed an algorithm, KC-SMART, that bases its estimate of the magnitude of the CNA at a given genomic location on kernel convolution (Klijn et al., 2008). This accounts for the intensity of the probe signal, its local genomic environment and the signal distribution across multiple samples. Results: Here we extend the approach to allow comparative analyses of two groups of samples and introduce the R implementation of these two approaches. The comparative module allows for a supervised analysis to be performed, to enable the identification of regions that are differentially aberrated between two user-defined classes. We analyzed data from a series of B- and T-cell lymphomas and were able to retrieve all positive control regions (VDJ regions) in addition to a number of new regions. A t-test employing segmented data, that we implemented, was also able to locate all the positive control regions and a number of new regions but these regions were highly fragmented. Conclusions: KC-SMARTR offers recurrent CNA and class specific CNA detection, at different genomic scales, in a single package without the need for additional segmentation. It is memory efficient and runs on a wide range of machines. Most importantly, it does not rely on data discretization and therefore maximally exploits the biological information in the aCGH data.MediamaticsElectrical Engineering, Mathematics and Computer Scienc
Global transcriptional responses of fission and budding yeast to changes in copper and iron levels: a comparative study
Analysis of genome-wide responses to changing copper and iron levels in budding and fission yeast reveals conservation of only a small core set of genes and remarkable differences in the responses of the two yeasts to excess copper
Alzheimer's disease
In this Seminar, we highlight the main developments in the field of Alzheimer's disease. The most recent data indicate that, by 2050, the prevalence of dementia will double in Europe and triple worldwide, and that estimate is 3 times higher when based on a biological (rather than clinical) definition of Alzheimer's disease. The earliest phase of Alzheimer's disease (cellular phase) happens in parallel with accumulating amyloid β, inducing the spread of tau pathology. The risk of Alzheimer's disease is 60-80% dependent on heritable factors, with more than 40 Alzheimer's disease-associated genetic risk loci already identified, of which the APOE alleles have the strongest association with the disease. Novel biomarkers include PET scans and plasma assays for amyloid β and phosphorylated tau, which show great promise for clinical and research use. Multidomain lifestyle-based prevention trials suggest cognitive benefits in participants with increased risk of dementia. Lifestyle factors do not directly affect Alzheimer's disease pathology, but can still contribute to a positive outcome in individuals with Alzheimer's disease. Promising pharmacological treatments are poised at advanced stages of clinical trials and include anti-amyloid β, anti-tau, and anti-inflammatory strategies
BRCA1-mutated and basal-like breast cancers have similar aCGH profiles and a high incidence of protein truncating TP53 mutations
BRCA1-mutated and basal-like breast cancers have similar aCGH profiles and a high incidence of protein truncating TP53 mutations
A novel CCM2 variant in a family with non-progressive cognitive complaints and cerebral microbleeds
Lobar cerebral microbleeds are most often sporadic and associated with Alzheimer's disease. The aim of our study was to identify the underlying genetic defect in a family with cognitive complaints and multiple lobar microbleeds and a positive family history for early onset Alzheimer's disease. We performed exome sequencing followed by Sanger sequencing for validation purposes on genomic DNA of three siblings with cognitive complaints, reduced amyloid-beta-42 in CSF and multiple cerebral lobar microbleeds. We checked for the occurrence of the variant in a cohort of 363 patients with early onset dementia and/or microbleeds. A novel frameshift variant (c.236_237delAC) generating a premature stop codon in the CCM2 gene shared by all three siblings was identified. Pathogenicity of the variant was supported by the presence of cerebral cavernous malformations in two of the siblings and by the absence of the variant exome variant databases. Two siblings were homozygous for APOE-ϵ4; one heterozygous. The cognitive complaints, reduced amyloid-beta-42 in CSF and microbleeds suggest preclinical Alzheimer's disease, but the stability of the cognitive complaints does not. We hypothesize that the phenotype in this family may be due to a combination of the CCM2 variant and the APOE status. © 2016 The Authors. American Journal of Medical Genetics Part B: Neuropsychiatric Genetics Published by Wiley Periodicals, Inc
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