100 research outputs found
Study of radiation feedback during formation of Population III stars in primordial minihalos
In this thesis, we utilize novel radiation transfer technique called SimpleX to study complex ionization and dissociation processes in Population III star formation around 400 million years after the Big Bang. The first part describes the SimpleX method and its implementation as a radiation transfer code SPRAI in the hydrodynamic code Arepo. We test it on several standard test cases and demonstrate its usability for physically accurate calculations in the astrophysical context. The second part presents our model of first-star formation and discuss our results. We follow the collapse of the primordial gas cloud in the central regions of a minihalo. The collapse of the gas is evolved until the first stars form in the densest regions. Subsequently, we cut out the central four parsecs region of the simulation around the star- forming area, continue the simulation for the next 20 kyrs, and simulate radiation feedback from individual stars. The results show that the effect of the ionizing radiation strongly depends on the starting position of the escaping photons and resolution. Simulations in the previous literature neglect accretion disks within the inner 10 AU around the stars. Our simulations show that the lack of resolution leads to an overestimation of the escaping ionizing photons from the accreting Population III stars. We report the trapping of the ionizing radiation on the scale length of the height of the accretion disk
Factors affecting the replacement of wooden harvesting bins with plastic equivalents for the New Zealand kiwifruit industry
The New Zealand Kiwifruit Industry is one of the biggest in the world. New Zealand grown kiwifruit is exported to more than 60 countries with Europe, Japan, Asia and U.S being the major markets. Currently, wooden bins are used for picking, handling and storing kiwifruit. Horticulture industries in many countries including the U.S, Europe, and Australia started using plastic harvesting bins over 40 years ago due to additional benefits of using plastic. However, this technology is still not put into practice in New Zealand mainly due to wood availability, familiarity with wooden bins and lack of knowledge reflecting the benefits of plastic harvesting bins. In this study, physical damage to kiwifruit in contact to different types of wooden and plastic harvesting bins was quantified and compared. The objective of the research was to indentify various physical damage mechanisms to kiwifruit and their relative significance during harvesting and storage. Mechanical damage was simulated as compression, abrasion and impact tests, conducted under laboratory conditions. The main finding of this research was that contact with wooden surfaces caused a significant amount of visible damage to kiwifruit, more so than any plastic surface. In terms of venting, 10mm vents in plastic showed least amount of damage. Compression on 10 mm plastic vents resulted in only 10 % fruit rejection , which was the minimum among all tests under ambient and coolstorage conditions. Almost all tests with wood resulted in 100% fruit rejection; this means that the whole bottom layered fruit would be rejected from a wooden bin. No significant differences were observed in percentage mass loss of fruit compressed on different wooden surfaces for both 10 and 25N firmness fruit under ambient and coolstorage conditions. This suggested that for wood, having flat or vented surface does not make a difference in percentage mass loss. It was found that impacting fruit on wooden and flat plastic surfaces caused about 30% fruit bruising, however, no bruising was observed in fruit impacted on vented plastic surfaces. It can be concluded that plastic bins are superior to wooden bins due to less fruit wastage and bruising. The research established that the initial investment of replacing a wooden harvesting with a plastic bin can be recovered within first 5 years. In addition, plastic bin would recover more than its cost by savings on less fruit rejection
Does vitamin D supplementation reduce asthma exacerbations?
Q: Does vitamin D supplementation reduce asthma exacerbations? Evidence-based answer: YES, to some extent it does, and primarily in patients with low vitamin D levels. Supplementation reduces asthma exacerbations requiring systemic steroids by 30% overall in adults and children with mild-to-moderate asthma (number needed to treat [NNT] = 7.7). The outcome is driven by the effect in patients with vitamin D levels < 25 nmol/L (NNT = 4.3), however; supplementation doesn't decrease exacerbations in patients with higher levels. Supplementation also reduces, by a smaller amount (NNT = 26.3), the odds of exacerbations requiring emergency department care or hospitalization (strength of recommendation [SOR]: A, meta-analysis of randomized controlled trials [RCTs]). In children, vitamin D supplementation may also reduce exacerbations and improve symptom scores (SOR: C, low-quality RCTs). Vitamin D doesn't improve forced expiratory volume in 1 second (FEV1) or standardized asthma control test scores. Also, it isn't associated with serious adverse effects (SOR: A, meta-analysis of RCTs).Jaspreet Jaura, MD; Gary Kelsberg, MD (Valley Family Medicine Residency, University of Washington at Valley Medical Center, Renton); Sarah Safranek, MLIS (University of Washington Health Sciences Library, Seattle)Includes bibliographical reference
Does vitamin D supplementation reduce asthma exacerbations?
Q: Does vitamin D supplementation reduce asthma exacerbations? Evidence-based answer: YES, to some extent it does, and primarily in patients with low vitamin D levels. Supplementation reduces asthma exacerbations requiring systemic steroids by 30% overall in adults and children with mild-to-moderate asthma (number needed to treat [NNT] = 7.7). The outcome is driven by the effect in patients with vitamin D levels < 25 nmol/L (NNT = 4.3), however; supplementation doesn't decrease exacerbations in patients with higher levels. Supplementation also reduces, by a smaller amount (NNT = 26.3), the odds of exacerbations requiring emergency department care or hospitalization (strength of recommendation [SOR]: A, meta-analysis of randomized controlled trials [RCTs]). In children, vitamin D supplementation may also reduce exacerbations and improve symptom scores (SOR: C, lowquality RCTs). Vitamin D doesn't improve forced expiratory volume in 1 second (FEV1) or standardized asthma control test scores. Also, it isn't associated with serious adverse effects (SOR: A, meta-analysis of RCTs).Jaspreet Jaura, MD; Gary Kelsberg, MD (Valley Family Medicine Residency, University of Washington at Valley Medical Center, Renton); Sarah Safranek, MLIS (University of Washington Health Sciences Library, Seattle)Includes bibliographical reference
Robotic assembly of splined shaft-hole using hybrid compliance control and machine learning based logic branching algorithm
A prospective study of metformin versus myoinositol plus d-chiroinositol combination therapy in polycystic ovarian syndrome
Background: Polycystic ovarian syndrome (PCOS) is one of the most common endocrine disorders in women of reproductive age. Insulin resistance and resultant hyperinsulinemia contribute to hyperandrogenism in these patients. Weight loss or pharmacologic interventions that lower insulin levels reduce androgen levels. This study was planned to evaluate efficacy of metformin versus myoinositol plus d-chiroinositol combination therapy in PCOS patients and its effects on clinical, hormonal and radio diagnostic dimensions.Methods: This was a prospective study for nine months. 50 newly diagnosed PCOS patients from the Department of Obstetrics and Gynaecology, Government Medical College (GMC), Amritsar, were randomly divided into 2 groups. One group was given metformin 500 mg twice daily and another myoinositol plus d-chiroinositol 1000 mg twice daily for 9 months. Follow up was done at 3, 6, 9 months. At each visit, ultrasonography and hormone levels were evaluated. Informed consent was taken. The approval of the Institutional Ethics Committee, GMC, Amritsar was also obtained.Results: The percentage change in free testosterone levels (22.46±6.47) and insulin levels (34.24±15.02) show statistically significant decrease in group 2 (p<0.001). There was statistically significant (p<0.05) fall in AMH levels (22.41±7.78) in group 1. There was no statistically significant difference between the 2 groups in ovarian volume on ultrasonography, random blood glucose levels, luteinizing hormone (LH), follicle-stimulating hormone (FSH) levels, estrogen and progesterone levels.Conclusions: It was observed that both treatments are equally effective in the treatment of polycystic ovarian syndrome with better tolerability in myoinositol and d-chiroinositol group
Diseño de un sistema de control interno para el mejoramiento de la gestión administrativa y financiera para la Librería y Papelería Aguilar de la ciudad de Loja, provincia de Loja, período 2015
El Diseño de un Sistema de Control Interno para la Librería y Papelería Aguilar de la ciudad de Loja, provincia de Loja, periodo 2015, con la finalidad de mejorar la gestión administrativa y financiera a través de herramientas de control. Para el desarrollo del sistema se realizó cuestionarios de control interno lo que permitió conocer la situación de la empresa y proponer alternativas que coadyuve a potencializar factores que mejoren el control de procedimientos para toda empresa, mediante la siguiente estructura:
Reglamento para Crédito y Cobranza, Reglamento para Adquisiciones, Manual de Funciones y manual Contable. Como resultado encontramos que el sistema de control interno permitirá que los procedimientos se manejen por medio de un manual de procedimientos administrativos y financieros para todas las áreas, además de contar con una organización estructural y funcional definida, así el personal definirá su rol y
funciones de acuerdo a su perfil profesional cuyo efecto se ve reflejado en el manejo interno de la institución y la atención al cliente. Se recomienda aplicar el sistema propuesto, su impacto en cuanto a lo económico, social, se ha determinado como positivo, lo cual hace ver que mediante la ejecución del mismo se logrará mejorar la gestión administrativa y financiera.In order to improve the administrative and financial management through tools of control, the design of an Internal Control System for the Bookstore and Stationery Aguilar in Loja, during the period 2015 was carried out. For the system development, internal control questionnaires were performed, which allowed to know the company situation and propose alternatives to contribute enhance factors improving the company procedures control, by means of the following structure: Regulation for Credit and Collection, Regulations for Acquisitions, Function Manual and Accounting Manual. As a result, it is found that the internal control system will allow procedures to be managed through a manual of administrative and financial procedures for all areas, in addition to having a defined structural and functional organization, so the define their role and functions according to their professional profile whose effect is reflected in the internal management of the institution and customer service. It is recommended to apply the proposed system, its impact in terms of economic and social, has been determined as positive what makes it possible to see that through its implementation it is possible to improve administrative and financial management
Comprobación del estado del aislamiento en máquinas eléctricas rotativas mediante la aplicación de ensayos offline
[EN] This thesis intends to determine the real condition of the insulation of a rotating electrical machine, by means of a set of tests that will be applied in the insulation system of real machines; this process will be applied to both asynchronous and synchronous motors. Two different types of techniques exist; destructive tests and non-destructive tests. Among the first group, we can find the measurement of the insulation resistance, phase inductance, polarization index and dielectric absorption. On the other hand, when the development of the test will be feasible and the integrity of the machine will not be risked, destructive tests will be also developed, namely: hi-pot tests or surge tests. Most of these methods are invasive and require that the machine is disconnected from the mains to be able to measure the necessary parameters. Moreover, in the thesis, a detailed description of each test will be given, including necessary equipment, theoretical foundations as well as normalized limit values that will be used as thresholds to determine the machine condition.[ES] El presente trabajo pretende determinar el estado actual del aislamiento de una maquina eléctrica rotativa, por medio de una serie de ensayos y pruebas que se aplicaran en máquinas reales sobre su sistema aislante; este proceso se efectuará principalmente a motores síncronos y asíncronos. Existen dos tipos de técnicas a aplicar, una es de tipo destructivo y otras de no destructivo. Entre las pruebas y ensayos de tipo no destructivo se encuentran, la resistencia del aislamiento, inductancia de fase, índice de polarización y la relación de absorción dieléctrica. Por otro lado, cuando sea posible efectuarlo y no se ponga en riesgo la integridad del máquina, se procederá a realizar pruebas de carácter destructivo como el ensayo hi-pot, surge o rampa. La mayoría de estos métodos, son de tipo intrusivo y requieren que la máquina se encuentre generalmente fuera de funcionamiento (offline), para poder efectuar sobre ella alguna medición. Además, se pretende dar una descripción detallada de cada método aplicado, sus fundamentos, el equipamiento necesario para llevarlo a cabo, así como valores límites normalizados, que, al ser comparados con los resultados obtenidos a través de las pruebas y ensayos realizados, nos permitirán interpretar la condición en la que se encuentra el motor.Carrión Jaura, RD. (2016). Comprobación del estado del aislamiento en máquinas eléctricas rotativas mediante la aplicación de ensayos offline. Universitat Politècnica de València. http://hdl.handle.net/10251/76696TFG
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