TeV String State Excitation via High Energy Cosmic Neutrinos

We construct the open-string scattering amplitudes for neutrino-gluon collisions and evaluate the high energy neutrino-nucleon scattering cross section via string state excitations in the TeV string-scale scenario. We find that the neutrino-gluon scattering is the dominant contribution, 5-10 times larger than neutrino-quark processes, though black hole production may be larger than the string contribution at higher energies. We illustrate the observability of the string signal at the Auger Observatory and the IceCube neutrino telescope for a string scale about 1 TeV.Comment: version to appear in PL

Design of a Monolithic Compliant Swimming Robot

Compliant mechanisms use the flexibility of their members to transfer an input displacement, force or torque to another point on the mechanism through the large deformation of its flexible links or joints. Fewer number of links, no friction, no backlash and simple design are the most important features that make them an ideal candidate when light weight, low cost and high performance are desired. The only challenge while designing a compliant mechanism is deriving the equations of motion as flexible links or flexure hinges go under large deformation. We designed a monolithic compliant swimming robot consists of a dc motor, flexible links, rigid crank, ball bearing and a base. The crank is connected to the motor using the ball bearing. The tail is designed as a lumped compliant mechanism in which the elastic deformation concentrates more on the flexure hinges to mimic the fish tail. As the motor is actuated and crank starts rotating, the flexible link attached to the crank actuates the rigid link. Rigid link is also coupled with flexure hinges to restrict its motion to tail back and forth in the water. Mechanism cad model is created, and motion analysis are performed both in Solidworks and Adams View. The entire mechanism is 3D printed using PETG filament and preliminary results are obtained from experimental testing. It’s been observed that mechanism successfully swims in the forward direction through the deformation of the flexible links and tail. The next steps will be the investigation of other actuation methods such as magnets or shape memory alloy wires and control of motion using Arduino nano so that the swimming robot will follow a desired trajectory

Asymmetric Dark Matter from Leptogenesis

We present a new realization of asymmetric dark matter in which the dark matter and lepton asymmetries are generated simultaneously through two-sector leptogenesis. The right-handed neutrinos couple both to the Standard Model and to a hidden sector where the dark matter resides. This framework explains the lepton asymmetry, dark matter abundance and neutrino masses all at once. In contrast to previous realizations of asymmetric dark matter, the model allows for a wide range of dark matter masses, from keV to 10 TeV. In particular, very light dark matter can be accommodated without violating experimental constraints. We discuss several variants of our model that highlight interesting phenomenological possibilities. In one, late decays repopulate the symmetric dark matter component, providing a new mechanism for generating a large annihilation rate at the present epoch and allowing for mixed warm/cold dark matter. In a second scenario, dark matter mixes with the active neutrinos, thus presenting a distinct method to populate sterile neutrino dark matter through leptogenesis. At late times, oscillations and dark matter decays lead to interesting indirect detection signals.Comment: 32 pages + appendix, references added, minor change

Compilation of Scandinavian Studies Index, Volume 37 – Volume 71

With the generosity on the part of the Office of Research and Creative Design and the grant offered me, I was able to produce a significant piece of scholarly work that will contribute significantly to a major academic field: a subject-word index for the academic journal, Scandinavian Studies. The actual work for the project was completed between January and August 1999. Through my experiences, I was able to broaden my knowledge of a field of study which I consider very interesting in addition to gaining valuable skills relating to editing, formatting, and indexing in journalism

Effective-periodicity effects in Fibonacci slot arrays

In this Letter, the transmission properties of a nonperiodic array of slots arranged in the form of a Fibonacci sequence are investigated. By arranging the slots in this manner, an additional periodicity can be utilized, resulting in corresponding resonance features in the transmitted signal. By investigating the transmission response of a perforated metallic sheet over a broad frequency range (6–40 GHz), it is shown that this simple one-dimensional chain supports two periodicities, one due to the regular periodic separation and one due to average spacing—which is related to the golden ratio. This response replicates the resonant behavior of a two-dimensional periodic array with a single nonperiodic array also creating new families of diffraction lobes in the far-field region.MCIN/AEI/10.13039/501100011033 PID2020-116739GB-I00EPSRC EP/R004781/1EPSRC EP/L015331/

Malignant Acute Disseminated Encephalomyelitis (ADEM) Presenting as a Stroke Alert: A Case Report.

Acute disseminated encephalomyelitis (ADEM) is a rare illness. Generally characterized by encephalopathy and non-specific, heterogeneous neurological deficits depending on the location of the demyelinated lesions, ADEM is considered a clinical diagnosis with radiological findings that may or may not have supportive features based on the temporal relationship of an inciting factor and symptom onset. Even rarer, hyperacute or malignant ADEM can be defined by rapid symptom onset followed by catastrophic brain edema and its sequelae. We present a case of a patient who presented with an acute stroke with activation of a rapid sequence care pathway (stroke alert protocol) to mobilize resources that could expedite his care to determine eligibility for thrombolysis. ADEM was the definitive diagnosis with a subsequent rapid and treatment-refractory decline

Global human footprint on the linkage between biodiversity and ecosystem functioning in reef fishes

Copyright: © 2011 Mora et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.Difficulties in scaling up theoretical and experimental results have raised controversy over the consequences of biodiversity loss for the functioning of natural ecosystems. Using a global survey of reef fish assemblages, we show that in contrast to previous theoretical and experimental studies, ecosystem functioning (as measured by standing biomass) scales in a non-saturating manner with biodiversity (as measured by species and functional richness) in this ecosystem. Our field study also shows a significant and negative interaction between human population density and biodiversity on ecosystem functioning (i.e., for the same human density there were larger reductions in standing biomass at more diverse reefs). Human effects were found to be related to fishing, coastal development, and land use stressors, and currently affect over 75% of the world's coral reefs. Our results indicate that the consequences of biodiversity loss in coral reefs have been considerably underestimated based on existing knowledge and that reef fish assemblages, particularly the most diverse, are greatly vulnerable to the expansion and intensity of anthropogenic stressors in coastal areas

Netrin-3 Signals Through Serine Phosphorylation in Tetrahymena thermophila

The netrin family of proteins are structurally related to laminin and, while first discovered in the nematode Caenorhabditis elegans, are now known to be present in species throughout the animal kingdom, including humans. These proteins also have a wide variety of roles that include inhibition of apoptosis, chemorepulsion, and axonal guidance. Due to the results of previous studies involving netrin-1 in vertebrate systems, the current prevailing assumption is that netrins, when acting as chemorepellents, signal using tyrosine kinases. However, data that we gathered through phosphoserine-targeting ELISA assays and immunofluorescence microscopy demonstrates that the netrin-3 peptides signal Tetrahymena thermophila through serine phosphorylation instead, causing the ciliate protists to avoid netrin-3 peptides in response. Treatment with netrin-3 peptides also seems to cause mitotic inhibition in Tetrahymena, which can be reversed by addition of a serine kinase inhibitor. This new information suggests that netrin-3 may have physiological roles that have previously been unexplored

Gram-Negative Bacterial Infections: Research Priorities, Accomplishments, and Future Directions of the Antibacterial Resistance Leadership Group

Antimicrobial resistance in pathogenic gram-negative bacteria is one of the most pressing challenges in the field of infectious diseases and is one of 4 key areas of unmet medical need identified by the Antibacterial Resistance Leadership Group (ARLG). The mission of the Gram-Negative Committee is to advance our knowledge of these challenging infections and implement studies to improve patient outcomes. Studies have fallen primarily into 2 broad categories: prospective cohort studies and interventional trials. Among the observational studies, CRACKLE (Consortium on Resistance Against Carbapenems in Klebsiella pneumoniae and Other Enterobacteriaceae) has contributed seminal multicenter data describing risk factors and clinical outcomes of carbapenem-resistant Enterobacteriaceae (CRE) in sentinel US hospitals. Building on this success, CRACKLE II will expand the network to hospitals across the United States and Colombia. Similar protocols have been proposed to include Acinetobacter baumannii and Pseudomonas aeruginosa (SNAP and POP studies). In addition, the CREST study (Carbapenem-Resistant Enterobacteriaceae in Solid Organ Transplant Patients) has provided pivotal data on extended-spectrum β-lactamase (ESBL)-producing Enterobacteriaceae and CRE carriage among solid organ transplant recipients to inform management of this vulnerable patient population. Two clinical trials to define novel ways of using an existing antibiotic, fosfomycin, to treat ESBL-producing Enterobacteriaceae (one that has completed enrollment and the other in late protocol development) will determine the clinical efficacy of fosfomycin as step-down oral therapy to treat complicated urinary tract infections. Additional clinical studies and trials using immunotherapeutic or newly approved agents are also in the planning stage, with the main goals of generating actionable data that will inform clinical decision making and facilitate development of new treatment options for highly resistant gram-negative bacterial infections

Association of blood pressure variability and neurocognition in children with chronic kidney disease

Children with chronic kidney disease (CKD) and hypertension have increased blood pressure variability (BPV). Increased BPV has been associated with lower neurocognitive test scores in adults. Children with CKD are at risk for decreased neurocognitive function. Our objective was to determine if children with CKD and increased BPV had worse performance on neurocognitive testing compared with children with CKD and lower BPV