Asymptotic stability at infinity for differentiable vector fields of the plane

Let X:R2\Dr->R2 be a differentiable (but not necessarily C1) vector field, where r>0 and Dr={z\in R2:|z|\le r}. If for some e>0 and for all p\in R2\Dr, no eigenvalue of D_p X belongs to (-e,0]\cup {z\in\C:\mathcal{R}(z)\ge 0}, then (a)For all p\in R2\Dr, there is a unique positive semi--trajectory of X starting at p; (b)\mathcal{I}(X), the index of X at infinity, is a well defined number of the extended real line [-\infty,\infty); (c) There exists a constant vector v\in R2 such that if \mathcal{I}(X) is less than zero (resp. greater or equal to zero), then the point at infinity \infty of the Riemann sphere R2\cup\set{\infty} is a repellor (resp. an attractor) of the vector field X+v.Comment: 16 pages, 7 figure

The Profile of Executive Secretaries and Their Relationship with Labor Demands

The work shows an analysis related to the emergence of the profession of the executive secretariat, highlighting the importance of the functions performed by the people who occupy these positions, for the good performance of public and private institutions. The results of an investigation carried out in the GAD of the Portoviejo canton, of the province of Manabí in Ecuador, are presented, where the current performance of a group of people in the position of the executive secretariat is evaluated, where the positive evolution is shown. It has been experienced in the last years in the exercise of this profession in correspondence with the labor demands of the Autonomous Decentralized Government of the canton Portoviejo

Standardized experimental estimation of the maximum unnoticeable environmental displacement during eye blinks for redirect walking in virtual reality

Redirect walking is a technique that aims to manipulate the walking trajectories in immersive virtual reality settings by inducing unnoticeable displacements of the virtual environment. Taking into advantage the change blindness phenomenon, visual occlusion during eye blinks has been recently proposed to perform those displacements. This study determined the maximum unnoticeable displacement that can be performed in practical scenario, which proved to be near 0.8° of occlusion and disocclusion in both horizontal and vertical axes

Avaliação da dinâmica do transporte dos bovinos no Pantanal Sul-Matogrossense.

O presente trabalho visou definir, caracterizar, classificar os modais de transporte de bovinos e avaliar as atuais condições da infra-estrutura logística dos meios de transporte em quatro sub-regiões do Pantanal (Paiaguás, Nhecolândia, Nabileque e Paraguai), através de duas abordagens: a avaliação da dinâmica do transporte e comercialização dos bovinos e a avaliação da dinâmica do transporte fluvial dos bovinos no porto de Ladário, MS. This study aimed define, characterize and classify the modal transport of beef cattle and assess the current conditions of the infrastructure in logistic of transport, in three subregion of Pantanal (Paiaguás, Nhecolandia, Nabileque and Paraguay), through two approaches: the assessment of the dynamics of the transport and marketing of cattle and evaluation of the dynamics of the fluvial transport of cattle in the port of Ladário, MS

Local mapping of dissipative vortex motion

We explore, with unprecedented single vortex resolution, the dissipation and motion of vortices in a superconducting ribbon under the influence of an external alternating magnetic field. This is achieved by combing the phase sensitive character of ac-susceptibility, allowing to distinguish between the inductive-and dissipative response, with the local power of scanning Hall probe microscopy. Whereas the induced reversible screening currents contribute only inductively, the vortices do leave a fingerprint in the out-of-phase component. The observed large phase-lag demonstrates the dissipation of vortices at timescales comparable to the period of the driving force (i.e. 13 ms). These results indicate the presence of slow microscopic loss mechanisms mediated by thermally activated hopping transport of vortices between metastable states.Comment: 5 pages, 2 figure

Charge transport through bio-molecular wires in a solvent: Bridging molecular dynamics and model Hamiltonian approaches

We present a hybrid method based on a combination of quantum/classical molecular dynamics (MD) simulations and a mod el Hamiltonian approach to describe charge transport through bio-molecular wires with variable lengths in presence o f a solvent. The core of our approach consists in a mapping of the bio-molecular electronic structure, as obtained f rom density-functional based tight-binding calculations of molecular structures along MD trajectories, onto a low di mensional model Hamiltonian including the coupling to a dissipative bosonic environment. The latter encodes fluctuat ion effects arising from the solvent and from the molecular conformational dynamics. We apply this approach to the c ase of pG-pC and pA-pT DNA oligomers as paradigmatic cases and show that the DNA conformational fluctuations are essential in determining and supporting charge transport

Brain Gene Expression Signatures From Cerebrospinal Fluid Exosome RNA Profiling

While the Visual Impairment and Intracranial Pressure (VIIP) syndrome observations have focused on ocular symptoms, spaceflight has been also associated with a number of other performance and neurologic signs, such as headaches, cognitive changes, vertigo, nausea, sleep/circadian disruption and mood alterations, which, albeit likely multifactorial, can also result from elevation of intracranial pressure (ICP). We therefore hypothesize that these various symptoms are caused by disturbances in the neurophysiology of the brain structures and are correlated with molecular markers in the cerebrospinal fluid (CSF) as indicators of neurophysiological changes. Exosomes are 30-200 nm microvesicles shed into all biofluids, including blood, urine, and CSF, carrying a highly rich source of intact protein and RNA cargo. Exosomes have been identified in human CSF, and their proteome and RNA pool is a potential new reservoir for biomarker discovery in neurological disorders. The purpose of this study is to investigate changes in brain gene expression via exosome analysis in patients suffering from ICP elevation of varied severity (idiopathic intracranial hypertension -IIH), a condition which shares some of the neuroophthalmological features of VIIP, as a first step toward obtaining evidence suggesting that cognitive function and ICP levels can be correlated with biomarkers in the CSF. Our preliminary work, reported last year, validated the exosomal technology applicable to CSF analysis and demonstrated that it was possible to obtain gene expression evidence of inflammation processes in traumatic brain injury patients. We are now recruiting patients with suspected IIH requiring lumbar puncture at Baylor College of Medicine. Both CSF (5 ml) and human plasma (10 ml) are being collected in order to compare the pattern of differentially expressed genes observed in CSF and in blood. Since blood is much more accessible than CSF, we would like to determine whether plasma biomarkers for elevated ICP can be identified. This may eventually lead to a blood test to diagnose intracranial hypertension