4,632 research outputs found
Low power arcjet performance
An experimental investigation was performed to evaluate arc jet operation at low power. A standard, 1 kW, constricted arc jet was run using nozzles with three different constrictor diameters. Each nozzle was run over a range of current and mass flow rates to explore stability and performance in the low power engine. A standard pulse-width modulated power processor was modified to accommodate the high operating voltages required under certain conditions. Stable, reliable operation at power levels below 0.5 kW was obtained at efficiencies between 30 and 40 percent. The operating range was found to be somewhat dependent on constrictor geometry at low mass flow rates. Quasi-periodic voltage fluctuations were observed at the low power end of the operating envelope, The nozzle insert geometry was found to have little effect on the performance of the device. The observed performance levels show that specific impulse levels above 350 seconds can be obtained at the 0.5 kW power level
AA. VV., Dominicos en Mesoamérica, 500 Años, Provincia Santiago de México, (Suplemento de la Revista «Analogía Filosófica»), México 1992, 583 pp., 16 x 21. [RECENSIÓN]
AA. VV., Los Dominicos y el Nuevo Mundo, Actas del III Congreso Internacional, ed. Deimos, Madrid 1991, 852 pp., 17 x 24. [RECENSIÓN]
Scintigraphic Demonstration of Urine Extravasation Secondary to Acute Ureteral Obstruction: A Case Report and Some Considerations about Acute Ureteral Obstruction
Acute ureteral obstruction produces renal damage and complications that are proportional to the severity and length of the obstruction. Anatomic diagnosis of the obstruction may be insufficient to manage the patient. Intravenous urogram (IVU) is the method usually advised by radiologists to obtain functional information, but requires iodinated contrast agents. IVU anatomic information is superior to anatomic information obtained with renal scintigraphy, but normally the physician already has the anatomic information (unenhanced CT or ultrasound). A renal scan offers better physiologic information than the IVU, has neither adverse effects nor complications, is accurate to confirm or discard significant ureteral obstruction, and depicts obstruction complications. This paper presents a patient with spontaneous urine extravasation secondary to acute renal obstruction who is diagnosed with renal scintigraphy. The authors describe the scintigraphic signs of extraperitoneal, diffuse perinephric, urine extravasation and emphasize the role of renal scintigraphy in diagnosis and follow-up of renal colic
Antibiotic Prescribing Practices of Filipino Dentists
There are reports that dentists overprescribe antibiotics which may contribute to antibiotic resistance. This is an exploratory study on antibiotic prescribing practices of Filipino dentists using an online platform to form a basis for antimicrobial stewardship policy for dentists. A link to an online questionnaire using Survey Monkey was posted in a Closed Group Facebook account of Filipino dentists. Two hundred thirty (230) dentists participated. Data was analyzed by Survey Monkey. Amoxicillin is the first choice of antibiotics(71.18%), andclindamycin is the second (57.27%). Most respondents follow the indications for antibiotic therapy, however, some will prescribe antibiotics for conditions without indications. For dental procedures, 88.99% will prescribe for periodontal surgery, 75.45% for endodontic surgery, 68.3% for extraction of a tooth with chronic infection, 87.17% for third molar surgery, 26.7% for routine endodontics, and 23.56% for periodontal treatment without surgery. Not all of the respondents would prescribe for medical conditions that require antibiotic prophylaxis, while 60.36% will prescribe when in doubt in diagnosis, under time pressure (25.68%), and 48.67% considers patient preference. Only 10.48% of the respondents are very familiar with antimicrobial stewardship, while majority (69.74%) have not attended a lecture for antimicrobial stewardship for dentists.There is inappropriate antibiotic prescribing of participants on certain dental diseases, procedures, and medical conditions. Most respondents are not very familiar and have not attended a lecture on antimicrobial stewardship for specifically for dentists
Towards a Semantic Gas Source Localization under Uncertainty
Towards a Semantic Gas Source Localization under Uncertainty.Communications in Computer and Information Science book series (CCIS, volume 855), doi:10.1007/978-3-319-91479-4_42This work addresses the problem of efficiently and coherently
locating a gas source in a domestic environment with a mobile
robot, meaning efficiently the coverage of the shortest distance as possible
and coherently the consideration of different gas sources explaining
the gas presence. The main contribution is the exploitation, for the
first time, of semantic relationships between the gases detected and the
objects present in the environment to face this challenging issue. Our
proposal also takes into account both the uncertainty inherent in the
gas classification and object recognition processes. These uncertainties
are combined through a probabilistic Bayesian framework to provide a
priority-ordered list of (previously observed) objects to check. Moreover
the proximity of the different candidates to the current robot location
is also considered by a cost function, which output is used for planning
the robot inspection path. We have conducted an initial demonstration
of the suitability of our gas source localization approach by simulating
this task within domestic environments for a variable number of objects,
and comparing it with an greedy approach.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech
Características del suministro de leña al mercado energético doméstico en la ciudad de Santiago del Estero, Argentina
Casi la mitad de la población de la provincia de
Santiago del Estero, Argentina, emplea la leña como
combustible para cubrir sus necesidades energéticas
tanto para el consumo doméstico familiar como para
la producción a escala artesanal de alimentos
destinados a la venta.
Este trabajo analiza el uso intensivo de recursos
forestales escasos en el ámbito doméstico, así como
el desconocimiento de formas alternativas
generadoras de energía y la falta de previsión para
asegurarse la provisión de los mismos.
El objetivo de esta investigación es caracterizar el
modo de transacción y sus mecanismos referidos a la
leña en el mercado local describiendo el modo de
pago más empleado, así como los medios de
transporte, el origen de la leña, y una breve
caracterización de las tendencias acerca del recurso
y la actitud de cambio de actividad productiva ante
la escasez del mismo.
La metodología se basó en el empleo de encuestas
semi-estructuradas a consumidores de leña para uso
productivo artesanal de comidas y alimentos típicos
de la ciudad. Las encuestas contenían preguntas
acerca de la cantidad de leña consumida en la
producción de alimentos, el medio de pago, el origen
de la leña y la forma de traslado de la misma.
Los resultados revelan tres niveles de consumidores
según el peso de leña consumida. Se detectó la
presencia de un sistema de comercialización no
formal manejado con vehículos motorizados. Casi
toda la leña consumida es comprada y las
transacciones son todas del modo contado efectivo.___________________________________Almost half of the population of Santiago del Estero,
Argentina, uses firewood as fuel to meet their energy
needs for both family consumption and sale-oriented
production of food and meals at a craft level.
This work analyses the intensive use of scarce forest
resources within the domestic environment, the
ignorance about energy-generating alternative forms
as well as the lack of forecast for assuring their
supply.
The aim of this research is to characterize the way
and the mechanisms by which firewood is
commercialized locally, describing the most used
ways of payment, transportation, firewood origin
and including a brief characterization of the trends
as to the resource and the attitude towards changing
the productive activity to face its scarcity.
Methodologically, semi-structured surveys were
conducted among those using firewood for a craft
production of typical food and meals. The surveys
included questions concerning the quantity of
firewood employed in preparing foods, its origin,
and the ways it is hauled and paid.
The results reveal three different levels of consumers
according to the firewood they employ and detect
the existence of a non-formal system of
commercialization run by motorized vehicles. Both
the purchase of almost all firewood consumed and
transactions are made in cash
Población y Desarrollo: Objeto de reflexión Bioética
Según el último informe de Naciones Unidas sobre población mundial, se estima que la población aumentará hasta 9.3 mil millones en 2050 y a 10.1 mil millones en 2100.1 Tal crecimiento, que pudiera parecer exagerado, no lo es por muchas razones, especialmente si se mira la trasformación que ha vivido el globo en los últimos 30 años en relación con la tasa de fecundidad
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