3,637 research outputs found
Detecting exotic heavy leptons at the Large Hadron Collider
New almost-degenerate charged and neutral heavy leptons are a feature of a
number of theories of physics beyond the Standard Model. The prospects for
detecting these at the Large Hadron Collider using a time-of-flight technique
are considered, along with any cosmological or experimental constraints on
their masses. Based on a discovery criterion of 10 detected exotic leptons we
conclude that, with an integrated luminosity of 100 fb-1, it should be possible
to detect such leptons provided their masses are less than 950 GeV. It should
also be possible to use the angular distribution of the produced particles to
distinguish these exotic leptons from supersymmetric scalar leptons, at a
better than 90% confidence level, for masses up to 580 GeV
Simulating Reionization: Character and Observability
In recent years there has been considerable progress in our understanding of
the nature and properties of the reionization process. In particular, the
numerical simulations of this epoch have made a qualitative leap forward,
reaching sufficiently large scales to derive the characteristic scales of the
reionization process and thus allowing for realistic observational predictions.
Our group has recently performed the first such large-scale radiative transfer
simulations of reionization, run on top of state-of-the-art simulations of
early structure formation. This allowed us to make the first realistic
observational predictions about the Epoch of Reionization based on detailed
radiative transfer and structure formation simulations. We discuss the basic
features of reionization derived from our simulations and some recent results
on the observational implications for the high-redshift Ly-alpha sources.Comment: 3 pages, to appear in the Proceedings of First Stars III, Santa Fe,
July 2007, AIP Conference Serie
A rare case of term viable secondary abdominal pregnancy following rupture of a rudimentary horn: a case report
<p>Abstract</p> <p>Introduction</p> <p>Abdominal pregnancy is a rare event, but one that represents a grave risk to the health of the pregnant woman. An abdominal pregnancy is defined as an ectopic pregnancy that implants in the peritoneal cavity. Early abdominal pregnancy is self-limited by hemorrhage from trophoblastic invasion with complete abortion of the gestational sac that leaves a discrete crater. Advanced abdominal pregnancy is a rare event, with high fetal and maternal morbidity and mortality.</p> <p>Case presentation</p> <p>This is a case report of a 22-year-old primigravida with an abdominal pregnancy from a ruptured rudimentary horn. She was diagnosed as a case of term pregnancy with placenta previa with a transverse fetal lie and cervical fibroid and was prepared for an elective cesarean section. Intra-operatively, a live term female baby was extracted from the peritoneal cavity and it turned out to be an abdominal pregnancy from a ruptured rudimentary horn of a unicornuate uterus, which is a very rare condition. Mother and baby were in good condition after such a catastrophic event.</p> <p>Conclusion</p> <p>This case illustrates a rare obstetric condition which can be a severe catastrophic condition leading to maternal mortality and morbidity. It is imperative for every obstetrician to have in mind the possibility of abdominal pregnancy, although rare, especially in pregnant patients with persistent abdominal pain and painful fetal movements.</p
Molecular basis for passive immunotherapy of Alzheimer's disease
Amyloid aggregates of the amyloid-{beta} (A{beta}) peptide are implicated in the pathology of Alzheimer's disease. Anti-A{beta} monoclonal antibodies (mAbs) have been shown to reduce amyloid plaques in vitro and in animal studies. Consequently, passive immunization is being considered for treating Alzheimer's, and anti-A{beta} mAbs are now in phase II trials. We report the isolation of two mAbs (PFA1 and PFA2) that recognize A{beta} monomers, protofibrils, and fibrils and the structures of their antigen binding fragments (Fabs) in complex with the A{beta}(1–8) peptide DAEFRHDS. The immunodominant EFRHD sequence forms salt bridges, hydrogen bonds, and hydrophobic contacts, including interactions with a striking WWDDD motif of the antigen binding fragments. We also show that a similar sequence (AKFRHD) derived from the human protein GRIP1 is able to cross-react with both PFA1 and PFA2 and, when cocrystallized with PFA1, binds in an identical conformation to A{beta}(1–8). Because such cross-reactivity has implications for potential side effects of immunotherapy, our structures provide a template for designing derivative mAbs that target A{beta} with improved specificity and higher affinity
Character building in childrens’ online information behaviours: applying a virtue epistemology perspective to information literacy.
This paper advances our understanding of the theoretical and practical challenges of developing intellectual character in children’s online information behaviours. We argue that widely reported issues such as misinformation and disinformation extend IL education beyond considerations of ability to considerations of disposition, and highlight this as an understudied topic within IL education. We introduce the classical concept of intellectual character and discuss virtues traits in the IL context. Applying Baehr’s nine intellectual virtues to two commonly cited IL models, we evidence limited presence of virtues in IL models, and propose an important agenda for future research
Super-resolution far-field ghost imaging via compressive sampling
Much more image details can be resolved by improving the system's imaging
resolution and enhancing the resolution beyond the system's Rayleigh
diffraction limit is generally called super-resolution. By combining the sparse
prior property of images with the ghost imaging method, we demonstrated
experimentally that super-resolution imaging can be nonlocally achieved in the
far field even without looking at the object. Physical explanation of
super-resolution ghost imaging via compressive sampling and its potential
applications are also discussed.Comment: 4pages,4figure
A single-photon transistor using nano-scale surface plasmons
It is well known that light quanta (photons) can interact with each other in
nonlinear media, much like massive particles do, but in practice these
interactions are usually very weak. Here we describe a novel approach to
realize strong nonlinear interactions at the single-photon level. Our method
makes use of recently demonstrated efficient coupling between individual
optical emitters and tightly confined, propagating surface plasmon excitations
on conducting nanowires. We show that this system can act as a nonlinear
two-photon switch for incident photons propagating along the nanowire, which
can be coherently controlled using quantum optical techniques. As a novel
application, we discuss how the interaction can be tailored to create a
single-photon transistor, where the presence or absence of a single incident
photon in a ``gate'' field is sufficient to completely control the propagation
of subsequent ``signal'' photons.Comment: 20 pages, 4 figure
Neoliberalisation and 'lad cultures' in higher education
This paper links HE neoliberalisation and ‘lad cultures’, drawing on interviews and focus groups with women students. We argue that retro-sexist ‘laddish’ forms of masculine competitiveness and misogyny have been reshaped by neoliberal rationalities to become modes of consumerist sexualised audit. We also suggest that neoliberal frameworks scaffold an individualistic and adversarial culture among young people that interacts with perceived threats to men’s privilege and intensifies attempts to put women in their place through misogyny and sexual harassment. Furthermore, ‘lad cultures’, sexism and sexual harassment in higher education may be invisibilised by institutions to preserve marketability in a neoliberal context. In response, we ask if we might foster dialogue and partnership between feminist and anti-marketisation politics
Adaptive Lévy processes and area-restricted search in human foraging
A considerable amount of research has claimed that animals’ foraging behaviors display movement lengths with power-law distributed tails, characteristic of Lévy flights and Lévy walks. Though these claims have recently come into question, the proposal that many animals forage using Lévy processes nonetheless remains. A Lévy process does not consider when or where resources are encountered, and samples movement lengths independently of past experience. However, Lévy processes too have come into question based on the observation that in patchy resource environments resource-sensitive foraging strategies, like area-restricted search, perform better than Lévy flights yet can still generate heavy-tailed distributions of movement lengths. To investigate these questions further, we tracked humans as they searched for hidden resources in an open-field virtual environment, with either patchy or dispersed resource distributions. Supporting previous research, for both conditions logarithmic binning methods were consistent with Lévy flights and rank-frequency methods–comparing alternative distributions using maximum likelihood methods–showed the strongest support for bounded power-law distributions (truncated Lévy flights). However, goodness-of-fit tests found that even bounded power-law distributions only accurately characterized movement behavior for 4 (out of 32) participants. Moreover, paths in the patchy environment (but not the dispersed environment) showed a transition to intensive search following resource encounters, characteristic of area-restricted search. Transferring paths between environments revealed that paths generated in the patchy environment were adapted to that environment. Our results suggest that though power-law distributions do not accurately reflect human search, Lévy processes may still describe movement in dispersed environments, but not in patchy environments–where search was area-restricted. Furthermore, our results indicate that search strategies cannot be inferred without knowing how organisms respond to resources–as both patched and dispersed conditions led to similar Lévy-like movement distributions
Corelation Between Sum of Precordial ST Depression in Acute Inferior Myocardial Infarction with Stenosis Severity of Left Anterior Descending Artery
Background : There were many studies proved that precordial ST depression in Inferior STEMI show LAD disease from angiografi, but there were also many who unproved . Altought LAD disease was not the main cause of precordial ST depression in Inferior STEMI, but there were many patients with Inferior STEMI who had high grade LAD disease. Sum of precordial ST depression is one of ECG criteria that can help us to prove it . The aim of this study in to know if there is corelation between sum of precordial ST depression with LAD disease and the severity of LAD disease in Inferior STEMI patients with precordial ST depression .
Methods : We analized 60 patients inferior STEMI with precordial ST depression onset less than 24 hours that hospitalized in Haji Adam Malik General Hospital since December 2013-June 2017. Patients were divided in to 4 groups based on sum of precordial ST depression. Bivariate analysis were made to see the corelation between sum of precordial ST depression with LAD disease and severity of LAD, p value < 0.05 is statistically significant.
Result : Bivariate analysis show that there is strong corelation between sum of precordial ST depression with LAD disease (p=0.01). Sum of precordial ST depression also corelate with severity of LAD (p=0.01). There are also corelation with location of the lesion in proximal LAD and the complexity of the lesion but not statistically significant (p=0.233 and p=0.102). Analysis ROC curve sum of precordial ST depression to LAD disease give the cut off ≥5.15 mm with sensitivity 70% and spesificity 76.2%(AUC 0,752 ,95% CI: 0,620 – 0,883 p<0,001)
Conclusion : There is strong corelation between sum of precordial ST depression with high grade LAD disease. The more the sum of precordial ST depression the more posibility high degree LAD disease ( p=0.01)
- …