1,267 research outputs found
Estratigrafía y estructura de los Andes Centrales Argentinos entre los 30º y 31º de Latitud Sur
In a cross-section through the Argentine central Andes, two large groups of rocks can be distinguished: a Gondwanic (F'aleozoic) basement, and an Andean cover. The basement is constituted by manne sedimentary units, intruded by Upper Paleozoic granitoid rocks. The most important Gondwanic structures, are East verging thrust and related folds. The Andean cover has a volcanic and volcanoclastic origin with some interbedded continental sedimentary rocks. The lower Permo-Tnassic unit (Choiyoi Group) is linked to an extensional tectonic event, and a Neogene sequence is connected to a compressional tectonic event that produced the inversion of the previous extensional features. The amount of Andean shortening calculated fiom cross sections is of about 10%. Most of the shortening in the Andean Cordillera was transferred to the Precordillera through the detachment fault. The up-lift of the Pampeanas area is linked with a new lower detachment fault
Develando el sindrome de Burnout en profesores de primero y segundo ciclo de Educacion General Basica de una escuela rural de la Zona Central de Chile
193 p.El estudio que a continuación se presenta es del tipo cualitativo, y tiene como objetivo aproximarnos a la comprensión del fenómeno de Burnout, sus causas, características y consecuencias, y sus complejas dimensiones en profesores de educación básica. Se busca develar el grado de ausencia o presencia del síndrome, identificando cual es el impacto que produce en el clima organizacional y fundamentalmente en el desempeño escolar de la organización. Para ello se construyó un marco teórico que nos permite introducirnos en la literatura para saber que nos aporta respecto de este tópico la psicología, sociología de la profesión y la teoría organizacional. Nuestro Chile vive ya desde hace algunos anos un proceso de reforma que tiene como finalidad mejorar la calidad de los aprendizajes de los educandos de todos los niveles, sabemos que en esto el rol del profesor es fundamental puesto que de el dependen los cambios verdaderos en el aula; por ello, pensamos que los profesores son el eje fundamental de la transformación de la sociedad, sociedad que demanden a estos permanentemente nuevos desafíos para producir los cambios requeridos. Estas políticas educativas llevan implícitas una serie de exigencias, que responden a las necesidades detectadas en la realidad de las comunidades, enfrentándose al aula en muchas oportunidades con grandes dificultades, como problemas sociales de los alumnos, escasez de material didáctico, indisciplina, bajo rendimiento, un clima organizacional deteriorado; sumándose todo esto a las bajas remuneraciones, todo lo cual va provocando en los docentes angustia, desencanto, frustración y desmotivación.En educación el riesgo psicológico esta muy presente por las diversas tensiones a que se encuentran sometidos los docentes, sean estas de tipo familiar, profesional o económicas, desencadenan un gran desgaste físico y psíquico, situación que nos ha motivado a realizar este estudio con el propósito de aproximarnos a la comprensión de este fenómeno: “Síndrome de Bornout” que puede afectar a muchos o pocos, pero puede tener múltiples consecuencias para la sociedad en su totalidad
Application of Nanotrap technology for high sensitivity measurement of urinary outer surface protein A carboxyl-terminus domain in early stage Lyme borreliosis
Objectives: Prompt antibiotic treatment of early stage Lyme borreliosis (LB) prevents progression to severe multisystem disease. There is a clinical need to improve the diagnostic specificity of early stage Lyme assays in the period prior to the mounting of a robust serology response. Using a novel analyte harvesting nanotechnology, Nanotrap particles, we evaluated urinary Borrelia Outer surface protein A (OspA) C-terminus peptide in early stage LB before and after treatment, and in patients suspected of late stage disseminated LB. Method: We employed Nanotrap particles to concentrate urinary OspA and used a highly specific anti-OspA monoclonal antibody (mAb) as a detector of the C-terminus peptides. We mapped the mAb epitope to a narrow specific OspA C-terminal domain OspA236-239 conserved across infectious Borrelia species but with no homology to human proteins and no cross-reactivity with relevant viral and non-Borrelia bacterial proteins. 268 urine samples from patients being evaluated for all categories of LB were collected in a LB endemic area. The urinary OspA assay, blinded to outcome, utilized Nanotrap particle pre-processing, western blotting to evaluate the OspA molecular size, and OspA peptide competition for confirmation. Results: OspA test characteristics: sensitivity 1.7 pg/mL (lowest limit of detection), % coefficient of variation (CV) = 8 %, dynamic range 1.7-30 pg/mL. Pre-treatment, 24/24 newly diagnosed patients with an erythema migrans (EM) rash were positive for urinary OspA while false positives for asymptomatic patients were 0/117 (Chi squared p < 10-6). For 10 patients who exhibited persistence of the EM rash during the course of antibiotic therapy, 10/10 were positive for urinary OspA. Urinary OspA of 8/8 patients switched from detectable to undetectable following symptom resolution post-treatment. Specificity of the urinary OspA test for the clinical symptoms was 40/40. Specificity of the urinary OspA antigen test for later serology outcome was 87.5 % (21 urinary OspA positive/24 serology positive, Chi squared p = 4.072e-15). 41 of 100 patients under surveillance for persistent LB in an endemic area were positive for urinary OspA protein. Conclusions: OspA urinary shedding was strongly linked to concurrent active symptoms (e.g. EM rash and arthritis), while resolution of these symptoms after therapy correlated with urinary conversion to OspA negative
Efficiency Evaluation of Fully Integrated On-board EV Battery Chargers with Nine-Phase Machines
A fully integrated on-board battery charger for future electric vehicles (EVs) has been recently introduced. It re-utilizes all the propulsion components of an EV in charging/vehicle-to-grid (V2G) modes, it does not require any additional components or hardware reconfiguration, and charging/V2G modes are realized with zero electromagnetic torque production. Both fast (three-phase) and slow (single-phase) charging are possible, with unity power factor operation at the grid side. The solution is based on the use of a triple three-phase machine and a nine-phase inverter/rectifier. This paper reports on the results of efficiency evaluation for the said system. Testing is performed using both a nine-phase induction machine and a nine-phase permanent magnet (PM) machine for a range of operating conditions in charging/V2G modes, with both three-phase and single-phase grid connection. Additionally, the impact of converter interleaving on the losses and efficiency is also studied. Losses are separated for different subsystems, thus providing an insight into the importance of optimization of different EV power train components from the efficiency point of view. Promising efficiencies, in the order of 90%, are achieved although none of the system components have been optimized
An Integrated On-Board Battery Charger with a Nine-Phase PM Machine
A fully integrated on-board battery charger for electrical vehicles (EVs) has been developed recently using a nine-phase machine. All the components used for propulsion are employed in the charging process, no additional components are required, and there is no need for hardware reconfiguration between charging and propulsion modes of operation. The proposed solution can be connected directly to single-phase or three-phase grid to perform charging, so that the expensive off-board charger infrastructure is not needed. The only requirement is to use a nine-phase machine in combination with a nine-phase inverter in the powertrain of the EV. This however inevitably brings in further advantages in the propulsion mode, such as increased fault tolerance and the current subdivision into more phases. The benefits of the topology, originally developed for an induction machine, make it interesting for further investigation. Therefore, the performance of the charger is examined here using a permanent magnet synchronous machine (PMSM). The results show that the charger topology is applicable to other types of synchronous machines and is, even more importantly, independent of the angular spatial shift between the individual three-phase windings of the nine-phase machine’s stator. The results are comparable with those obtained using an induction machine and confirm the viability of the solution in conjunction with the PMSM as a propulsion motor
Perinatal asphyxia: CNS development and deficits with delayed onset
Perinatal asphyxia constitutes a prototype of obstetric complications occurring when pulmonary
oxygenation is delayed or interrupted. The primary insult relates to the duration of the period
lacking oxygenation, leading to death if not re-established. Re-oxygenation leads to a secondary
insult, related to a cascade of biochemical events required for restoring proper function. Perinatal
asphyxia interferes with neonatal development, resulting in long-term deficits associated to mental
and neurological diseases with delayed clinical onset, by mechanisms not yet clarified.
In the experimental scenario, the effects observed long after perinatal asphyxia have been explained
by over expression of sentinel proteins, such as poly(ADP-ribose) polymerase-1 (PARP-1),
competing for NAD+ during re-oxygenation, leading to the idea that sentinel protein inhibition
constitutes a suitable therapeutic strategy. Asphyxia induces transcriptional activation of proinflammatory
factors, in tandem with PARP-1 overactivation, and pharmacologically induced
PARP-1 inhibition also down-regulates the expression of proinflammatory cytokines.
Nicotinamide has been proposed as a suitable PARP-1 inhibitor. Its effect has been studied in
an experimental model of global hypoxia in rats. In that model, the insult is induced by immersing
rat foetuses into a water bath for various periods of time. Following asphyxia, the pups are
delivered, treated, and nursed by surrogate dams, pending further experiments. Nicotinamide
rapidly distributes into the brain following systemic administration, reaching steady state
concentrations sufficient to inhibit PARP-1 activity for several hours, preventing several of the
long-term consequences of perinatal asphyxia, supporting the idea that it constitutes a lead for
exploring compounds with similar or better pharmacological profiles
On interconnecting and orchestrating components in disaggregated data centers:The dReDBox project vision
Computing systems servers-low-or high-end ones have been traditionally designed and built using a main-board and its hardware components as a 'hard' monolithic building block; this formed the base unit on which the system hardware and software stack design build upon. This hard deployment and management border on compute, memory, network and storage resources is either fixed or quite limited in expandability during design time and in practice remains so throughout machine lifetime as subsystem upgrades are seldomely employed. The impact of this rigidity has well known ramifications in terms of lower system resource utilization, costly upgrade cycles and degraded energy proportionality. In the dReDBox project we take on the challenge of breaking the server boundaries through materialization of the concept of disaggregation. The basic idea of the dReDBox architecture is to use a core of high-speed, low-latency opto-electronic fabric that will bring physically distant components more closely in terms of latency and bandwidth. We envision a powerful software-defined control plane that will match the flexibility of the system to the resource needs of the applications (or VMs) running in the system. Together the hardware, interconnect, and software architectures will enable the creation of a modular, vertically-integrated system that will form a datacenter-in-a-box
There's no place like OM:Vesicular sorting and secretion of the peptidylarginine deiminase of Porphyromonas gingivalis
The oral pathogen Porphyromonas gingivalis is one of the major periodontal agents and it has been recently hailed as a potential cause of the autoimmune disease rheumatoid arthritis. In particular, the peptidylarginine deiminase enzyme of P. gingivalis (PPAD) has been implicated in the citrullination of certain host proteins and the subsequent appearance of antibodies against citrullinated proteins, which might play a role in the etiology of rheumatoid arthritis. The aim of this study was to investigate the extracellular localization of PPAD in a large panel of clinical P. gingivalis isolates. Here we show that all isolates produced PPAD. In most cases PPAD was abundantly present in secreted outer membrane vesicles (OMVs) that are massively produced by P. gingivalis, and to minor extent in a soluble secreted state. Interestingly, a small subset of clinical isolates showed drastically reduced levels of the OMV-bound PPAD and secreted most of this enzyme in the soluble state. The latter phenotype is strictly associated with a lysine residue at position 373 in PPAD, implicating the more common glutamine residue at this position in PPAD association with OMVs. Further, one isolate displayed severely restricted vesiculation. Together, our findings show for the first time that neither the major association of PPAD with vesicles, nor P. gingivalis vesiculation per se, are needed for P. gingivalis interactions with the human host
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