918 research outputs found
Post-ISCO Ringdown Amplitudes in Extreme Mass Ratio Inspiral
An extreme mass ratio inspiral consists of two parts: adiabatic inspiral and
plunge. The plunge trajectory from the innermost stable circular orbit (ISCO)
is special (somewhat independent of initial conditions). We write an expression
for its solution in closed-form and for the emitted waveform. In particular we
extract an expression for the associated black-hole ringdown amplitudes, and
evaluate them numerically.Comment: 21 pages, 5 figures. v4: added section with numerical evaluation of
the ringdown amplitude
Paradoxical augmented relapse in alcohol-dependent rats during deep-brain stimulation in the nucleus accumbens
Case reports indicate that deep-brain stimulation in the nucleus accumbens may
be beneficial to alcohol-dependent patients. The lack of clinical trials and
our limited knowledge of deep-brain stimulation call for translational
experiments to validate these reports. To mimic the human situation, we used a
chronic-continuous brain-stimulation paradigm targeting the nucleus accumbens
and other brain sites in alcohol-dependent rats. To determine the network
effects of deep-brain stimulation in alcohol-dependent rats, we combined
electrical stimulation of the nucleus accumbens with functional magnetic
resonance imaging (fMRI), and studied neurotransmitter levels in nucleus
accumbens-stimulated versus sham-stimulated rats. Surprisingly, we report here
that electrical stimulation of the nucleus accumbens led to augmented relapse
behavior in alcohol-dependent rats. Our associated fMRI data revealed some
activated areas, including the medial prefrontal cortex and caudate putamen.
However, when we applied stimulation to these areas, relapse behavior was not
affected, confirming that the nucleus accumbens is critical for generating
this paradoxical effect. Neurochemical analysis of the major activated brain
sites of the network revealed that the effect of stimulation may depend on
accumbal dopamine levels. This was supported by the finding that brain-
stimulation-treated rats exhibited augmented alcohol-induced dopamine release
compared with sham-stimulated animals. Our data suggest that deep-brain
stimulation in the nucleus accumbens enhances alcohol-liking probably via
augmented dopamine release and can thereby promote relapse
RGS2 expression predicts amyloid-β sensitivity, MCI and Alzheimer's disease: genome-wide transcriptomic profiling and bioinformatics data mining
Alzheimer's disease (AD) is the most frequent cause of dementia. Misfolded protein pathological hallmarks of AD are brain deposits of amyloid-β (Aβ) plaques and phosphorylated tau neurofibrillary tangles. However, doubts about the role of Aβ in AD pathology have been raised as Aβ is a common component of extracellular brain deposits found, also by in vivo imaging, in non-demented aged individuals. It has been suggested that some individuals are more prone to Aβ neurotoxicity and hence more likely to develop AD when aging brains start accumulating Aβ plaques. Here, we applied genome-wide transcriptomic profiling of lymphoblastoid cells lines (LCLs) from healthy individuals and AD patients for identifying genes that predict sensitivity to Aβ. Real-time PCR validation identified 3.78-fold lower expression of RGS2 (regulator of G-protein signaling 2; P=0.0085) in LCLs from healthy individuals exhibiting high vs low Aβ sensitivity. Furthermore, RGS2 showed 3.3-fold lower expression (P=0.0008) in AD LCLs compared with controls. Notably, RGS2 expression in AD LCLs correlated with the patients' cognitive function. Lower RGS2 expression levels were also discovered in published expression data sets from postmortem AD brain tissues as well as in mild cognitive impairment and AD blood samples compared with controls. In conclusion, Aβ sensitivity phenotyping followed by transcriptomic profiling and published patient data mining identified reduced peripheral and brain expression levels of RGS2, a key regulator of G-protein-coupled receptor signaling and neuronal plasticity. RGS2 is suggested as a novel AD biomarker (alongside other genes) toward early AD detection and future disease modifying therapeutics
Signatures of particle collisions near extreme black holes
Finite-energy particles in free fall can collide with diverging
center-of-mass energy near rapidly rotating black holes. What are the most
salient observational signatures of this remarkable geometric effect? Here we
revisit the problem from the standpoint of the near-horizon extreme Kerr
geometry, where these collisions naturally take place. It is shown that the
ingoing particle kinematics admits a simple, universal form. Given a scattering
cross section, determination of emission properties is reduced to evaluation of
particular integrals on the sky of a near-horizon orbiting particle. We
subsequently apply this scheme to the example of single-photon bremsstrahlung,
substantiating past results which indicate that ejected particles are
observable, but their energies are bounded by the rest masses of the colliding
particles. Our framework is readily applicable for any scattering process.Comment: 11 pages, 4 figure
Revisiting Politicide: State Annihilation in Israel/Palestine
State annihilation is a persistent concern in Israel/Palestine. While the specter of Israel’s destruction increasingly haunts Israeli public political debates, the actual materialization of Palestinian statehood seems to be permanently suspended, caught in an ever-protracted process of state-building. The current paper claims that to understand the unfolding of the discursive formations, as well as the spatial dimensions of conflict and control in Israel/Palestine, we should explicate the workings of the processes of politicide. Politicide, in this regard, denotes the eradication of the political existence of a group and sabotaging the turning of a community of people into a polity. This analysis suggests that the insistence that the State of Israel is under threat of extinction should be understood as a speech act, a performative reiteration, which allows for the securitization of Israeli rule in the occupied Palestinian territory, a securitization which then serves to rationalize the ongoing concrete politicide of the Palestinians. Elaborating on the concept of politicide, and diverging from defining it solely through the use of brute violence, this examination suggests that what is often overlooked in discussions of politicide are the seemingly more benign means of its implementation, the micro-power mechanisms of spatial control, prohibitions and regulations
Exploring the Interplay Between Colorectal Cancer Subtypes Genomic Variants and Cellular Morphology: A Deep-Learning Approach
Molecular subtypes of colorectal cancer (CRC) significantly influence
treatment decisions. While convolutional neural networks (CNNs) have recently
been introduced for automated CRC subtype identification using H&E stained
histopathological images, the correlation between CRC subtype genomic variants
and their corresponding cellular morphology expressed by their imaging
phenotypes is yet to be fully explored. The goal of this study was to determine
such correlations by incorporating genomic variants in CNN models for CRC
subtype classification from H&E images. We utilized the publicly available
TCGA-CRC-DX dataset, which comprises whole slide images from 360 CRC-diagnosed
patients (260 for training and 100 for testing). This dataset also provides
information on CRC subtype classifications and genomic variations. We trained
CNN models for CRC subtype classification that account for potential
correlation between genomic variations within CRC subtypes and their
corresponding cellular morphology patterns. We assessed the interplay between
CRC subtypes' genomic variations and cellular morphology patterns by evaluating
the CRC subtype classification accuracy of the different models in a stratified
5-fold cross-validation experimental setup using the area under the ROC curve
(AUROC) and average precision (AP) as the performance metrics. Combining the
CNN models account for variations in CIMP and SNP further improved
classification accuracy (AUROC: 0.8470.01 vs. 0.7870.03, p0.01,
AP: 0.680.02 vs. 0.640.05)
SPRING: an RCT study of probiotics in the prevention of gestational diabetes mellitus in overweight and obese women
Background: Obesity is increasing in the child-bearing population as are the rates of gestational diabetes. Gestational diabetes is associated with higher rates of Cesarean Section for the mother and increased risks of macrosomia, higher body fat mass, respiratory distress and hypoglycemia for the infant. Prevention of gestational diabetes through life style intervention has proven to be difficult. A Finnish study showed that ingestion of specific probiotics altered the composition of the gut microbiome and thereby metabolism from early gestation and decreased rates of gestational diabetes in normal weight women. In SPRING (the Study of Probiotics IN the prevention of Gestational diabetes), the effectiveness of probiotics ingestion for the prevention of gestational diabetes will be assessed in overweight and obese women
Abstracts of papers presented at an international workshop on management of soilborne pathogens sponsored by the United States-Israel binational agricultural research and development fund (bard): March 1-5,1998 Ramat Rachel, Jerusalem, Israel
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