Graphene energy loss spectroscopy: Perpendicular case

AbstractThe energy loss of a fast charged particle probe incident on a two-dimensional graphene sheet is examined here. The fast particle motion is taken to be perpendicular to the 2D graphene sheet, which is considered to be in the degenerate limit of zero temperature. The response dynamics of the 2D graphene layer are described in the random phase approximation and the energy loss for particle motion perpendicular to the 2D graphene layer is calculated as a function of the velocity of the charged particle

Investigation of the Liverpool Bay mixing front using POLCOMS

Liverpool Bay, northwest UK, is a region of freshwater influence and hypertidal conditions. The river inflow from the 3 large estuary systems (Dee, Mersey and Ribble) forms a coastal front that moves < 10 km in response to semi-diurnal tidal straining and < 35 km due to the spring-neap cycle. The time variability of the density gradients in this coastal region are mainly controlled by salinity. Coastal observations are used in this study to improve the numerical simulation of the exchange process occurring at this front through improved spatial structure and temporal variability. A decade of Conductivity Temperature Depth (CTD) sensor observations were collected during cruises across a nearshore grid of monitoring stations. These data are used in addition to fixed mooring data that are near-continuous in time to validate numerical simulations using the 1-way nested Proudman Oceanographic Laboratory Coastal Ocean Modelling System (POLCOMS) at ~1.8km and 180m horizontal resolution. A downscaled simulation is used to investigate the influence of model resolution, inclusion of wetting and drying, diffusivity, turbulence advection and the influence of model boundary and initial conditions for select cruise periods in 2008. This year is chosen as a typical year with periods of calm and stormy conditions with variable river influence to investigate the seasonal frontal structure. A method to validate the spatial structure of the front is presented demonstrating the importance of a fine-resolution grid and improved physics to capture the details

Evolution of the pairing pseudogap in the spectral function with interplane anisotropy

We study the pairing pseudogap in the spectral function as a function of interplane coupling. The analytical expressions for the self-energy in the critical regime are obtained for any degree of anisotropy. The frequency dependence of the self-energy is found to be qualitatively different in two and three dimensions, and the crossover from two to three dimensional behavior is discussed. In particular, by considering the anisotropy of the Fermi velocity and gap along the Fermi surface, we can qualitatively explain recent photoemission experiments on high temperature superconductors concerning the temperature dependent Fermi arcs seen in the pseudogap phase.Comment: 20 pages, revtex, 5 encapsulated postscript figures include

Domestic Rivalry and Export Performance: Theory and Evidence from International Airline Markets

The much-studied relationship between domestic rivalry and export performance consists of those supporting a national-champion rationale, and those supporting a rivalry rationale. While the empirical literature generally supports the positive effects of domestic rivalry, the national-champion rationale actually rests on firmer theoretical ground. We address this inconsistency by providing a theoretical framework that illustrates three paths via which domestic rivalry translates into enhanced international exports. Furthermore, empirical tests on the world airline industry elicit the existence of one particular path - an enhanced firm performance effect - that connects domestic rivalry with improved international exports

A solution for improved simulation efficiency of a multi-domain marine power system model

Integrated Full Electric Propulsion (IFEP) marine power systems offer increased design flexibility and operational economy by supplying ship propulsion and service loads from a common electrical system. Predicting the behaviour of IFEP systems through simulation is important in reducing the design risk. However, the prevalence of power electronics and the potential for interaction between large electrical and mechanical systems introduce significant simulation challenges. This paper presents an integrated simulation tool, which brings together electrical, mechanical, thermal and hydrodynamic models, facilitating a holistic simulation capability. Approaches adopted for model validation and computational efficiency together with two case studies are discussed

Charge Stripes and Antiferromagnetism in Insulating Nickelates and Superconducting Cuprates

Neutron and X-ray scattering studies have provided strong evidence for coupled spatial modulations of charge and spin densities in layered nickelates and cuprates. The accumulated results for La(2-x)Sr(x)NiO(4+d) are consistent with the strongly-modulated topological-stripe concept. Clues from Nd-doped La(2-x)Sr(x)CuO(4) suggest similar behavior for the cuprates. The experimental results are summarized, and features that conflict with an interpretation based on a Fermi-surface instability are emphasized. A rationalization for the differences in transport properties between the cuprates and nickelates is given.Comment: 10pp., uses elsart.sty, 3 eps figures embedded with psfig; for proceedings of Spectroscopies in Novel Superconductors '97, J. Phys. Chem. Solid

Upper critical field for underdoped high-T_c superconductors. Pseudogap and stripe--phase

We investigate the upper critical field in a stripe--phase and in the presence of a phenomenological pseudogap. Our results indicate that the formation of stripes affects the Landau orbits and results in an enhancement of $H_{c2}$. On the other hand, phenomenologically introduced pseudogap leads to a reduction of the upper critical field. This effect is of particular importance when the magnitude of the gap is of the order of the superconducting transition temperature. We have found that a suppression of the upper critical field takes place also for the gap that originates from the charge--density waves.Comment: 7 pages, 5 figure

Interferon-λ cures persistent murine norovirus infection in the absence of adaptive immunity

Norovirus gastroenteritis is amajor public health burden worldwide. Although fecal shedding is important for transmission of enteric viruses, little is known about the immune factors that restrict persistent enteric infection. We report here that although the cytokines interferon-α (IFN-α) and IFN-β prevented the systemic spread of murine norovirus (MNoV), only IFN-λcontrolled persistent enteric infection. Infection-dependent induction of IFN-λ was governed by the MNoV capsid protein and correlated with diminished enteric persistence. Treatment of established infection with IFN-λ cured mice in a manner requiring nonhematopoietic cell expression of the IFN-λ receptor, Ifnlr1, and independent of adaptive immunity. These results suggest the therapeutic potential of IFN-λ for curing virus infections in the gastrointestinal tract

Vascular Endothelial Growth Factor-Related Pathways in Hemato-Lymphoid Malignancies

Angiogenesis is essential for malignant tumor growth. This has been documented for solid tumors, and there is an emerging evidence suggesting that tumor progression of hematolymphoid malignancies also depends on the induction of new blood vessel formation. The most important proangiogenic agent is vascular endothelial growth factor (VEGF), activating VEGF receptors 1 and 2. The available data on angiogenesis in hemato-lymphoid malignancies, such as acute leukemias, myelodysplastic syndromes, myeloproliferative neoplasms, multiple myeloma, and lymphomas, point towards the significance of autocrine and paracrine VEGF-mediated effects for proliferation and survival of leukemia/lymphoma cells in addition to tumor vascularization. Antiangiogenic strategies have become an important therapeutic modality for solid tumors. Several antiangiogenic agents targeting VEGF-related pathways are also being utilized in clinical trials for the treatment of hemato-lymphoid malignancies, and in some instances these pathways have emerged as promising therapeutic targets. This review summarizes recent advances in the basic understanding of the role of angiogenesis in hemato-lymphoid malignancies and the translation of such basic findings into clinical studies

Cognitive changes in patients with epilepsy identified through the MoCA test during neurology outpatient consultation

Introduction Epilepsy is a chronic neurological disorder that may occur alongside cognitive changes, with effects on multiple cognitive domains. Objective To compare the cognitive performance of patients with epilepsy and healthy controls through Montreal Cognitive Assessment (MoCA) during outpatient consultation at a reference diagnostic center in Colombia and analyze and the influencing factors. Materials and methodology One-hundred and four patients during neurology outpatient consultation in the city of Cartagena, Colombia, were assessed with the (MoCA) test, i.e., 54 people who consulted for headache and have not been diagnosed with epilepsy (NEP) and 50 with a diagnosis of epilepsy (EPs) according to the diagnostic criteria of the International League Against Epilepsy (ILAE). Results Significant differences were found in the total mean scores of the (MoCA) between (EPs) and (NPE) groups (t = 4.72; p < 0.01), particularly in attention (t = 3.22; p < 0.02) and memory (t = 5.04; p < 0.01) dimensions. Additionally, a significant association was observed between years of schooling and (MoCA) scores (p = 0,019) but not between socioeconomic level (p = 0,510), age (p = 0,452) and the frequency of seizures (p = 0,471). Discussion Patients with epilepsy show lower scores in several cognitive domains in respect of the control group. The (MoCA) has proven its appropriateness for cognitive screening in the contexts of clinical neurology outpatient consultation