1,126 research outputs found

    Shear waves in prestrained poroelastic media

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    Shear wave elastography measures shear wave speed in soft tissues for diagnostic purposes. In [1], shear wave speed was shown to depend on prestrain, but not necessarily prestress, in a perfused canine liver. We model this phenomenon by examining incremental waves in a pressurized poroelastic medium with incompressible phases. The analysis suggests novel restrictions on the strain energy functions for soft tissues

    O impacto dos distúrbios monetários na inflação e nos ciclos de negócios na economia iraniana

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    In this paper, we have investigated the effect of monetary disorders on inflation and business cycles in Iran’s economy during the period 1973 to 2012. Monetary disorders are defined by two indexes of monetary policy uncertainty and shock to liquidity growth. In the first step, the causal relationship of monetary policy uncertainty on real GDP fluctuations, employment fluctuations and inflation are estimated using Granger causality test. To this purpose, to follow Haghighat and Mohammad Gholipour Tapeh (2014), the conditional variance of liquidity growth extracted from models of GARCH family was applied as a substitute for monetary policy uncertainty. In the second stage, the reaction of economic growth, employment growth and inflation to the shock to liquidity growth are estimated using impulse response function technique derived from VAR model. The results indicate the existence of one-way Granger causality relation of monetary policy uncertainty in all three variables of real GDP fluctuations, employment fluctuations and inflation. Also, based on the results, impulse response function reduces the shock to liquidity growth as much as a standard deviation, real GDP growth and employment after a period and increases inflation. Accordingly, the hypothesis of the effect of monetary disorders on business cycles in Iran’s economy in the period of this research cannot be rejected.JEL classification: E23, E31, E32, E52En este documento, hemos investigado el efecto de los trastornos monetarios en la inflación y los ciclos económicos en la economía de Irán durante el período de 1973 a 2012. Los trastornos monetarios se definen por dos índices de incertidumbre de la política monetaria y el impacto del crecimiento de la liquidez. En el primer paso, la relación causal de la incertidumbre de la política monetaria sobre las fluctuaciones del PIB real, las fluctuaciones del empleo y la inflación se estiman mediante la prueba de causalidad de Granger. Para este propósito, siguiendo a Haghighat y Mohammad Gholipour Tapeh (2014), se aplicó la varianza condicional del crecimiento de la liquidez extraída de los modelos de la familia GARCH como sustituto de la incertidumbre de la política monetaria. En la segunda etapa, la reacción del crecimiento económico, el crecimiento del empleo y la inflación al impacto del crecimiento de la liquidez se estiman utilizando la técnica de función de respuesta al impulso derivada del modelo VAR. Los resultados indican la existencia de una relación de causalidad de Granger unidireccional de la incertidumbre de la política monetaria en las tres variables de fluctuaciones del PIB real, fluctuaciones del empleo e inflación. Además, en función de los resultados, la función de respuesta al impulso reduce el impacto del crecimiento de la liquidez tanto como una desviación estándar, el crecimiento del PIB real y el empleo después de un período y aumenta la inflación. En consecuencia, la hipótesis del efecto de los trastornos monetarios en los ciclos económicos de la economía de Irán en el período de esta investigación no puede ser rechazada.Clasificación JEL: E23, E31, E32, E52Neste artigo, investigamos o efeito dos distúrbios monetários sobre a inflação e os ciclos econômicos na economia do Irã durante o período de 1973 a 2012. Os distúrbios monetários são definidos por dois índices de incerteza da política monetária e por choque no crescimento da liquidez. No primeiro passo, a relação causal entre a incerteza da política monetária sobre as flutuações do PIB real, as flutuações do emprego e a inflação é estimada usando o teste de causalidade de Granger. Para este propósito, para seguir Haghighat e Mohammad Gholipour Tapeh (2014), a variância condicional do crescimento de liquidez extraída de modelos da família GARCH foi aplicada como um substituto para a incerteza da política monetária. No segundo estágio, a reação do crescimento econômico, crescimento do emprego e inflação ao choque para o crescimento da liquidez são estimados usando a técnica de função de resposta impulsiva derivada do modelo VAR. Os resultados indicam a existência de uma relação de causalidade de Granger unidirecional da incerteza da política monetária em todas as três variáveis de flutuações reais do PIB, flutuações do emprego e inflação. Além disso, com base nos resultados, a função de resposta ao impulso reduz o choque para o crescimento da liquidez, tanto quanto um desvio padrão, crescimento do PIB real e emprego após um período e aumenta a inflação. Consequentemente, a hipótese do efeito dos distúrbios monetários nos ciclos de negócios na economia do Irã no período desta pesquisa não pode ser rejeitada.Classificação JEL: E23, E31, E32, E5

    The dual of z-submodules of modules and some of extensions

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    Let R be a commutative ring with identity and M be an R-module. The purpose of this paper is to introduced the dual notion of z-submodules of M and some of extensions. Moreover, we investigate some properties of these classes of modules when M is a coreduced comultiplication R-module

    Effect of different Alphamune levels in artificial diet on growth parameters, digestibility and enzyme activity of rainbow trout, Oncorhynchus mykiss (Walbaum 1792)

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    This study was conducted to evaluate the effects of Alphamune, a mixed prebiotic composed of mannan-oligosaccharide and β-glucans, on the growth performance, digestibility and enzyme activity of rainbow trout, Oncorhynchus mykiss. A basal diet was formulated using common feed ingredients supplemented with Alphamune at 0, 0.5, 1, 2, and 4 g.kg^-1 leading to five experimental diets. Obtained results showed that inclusion of dietary Alphamune significantly increased the final weight and weight gain (p0.05). Also apparent digestibility coefficient (ADC) was not affected by dietary addition of the prebiotic (p>0.05). Our results indicated that amlayse and lipase activities were not significantly influenced by administration of different doses of Alphamune. The result also showed that trypsin activity was gradually increased with increasing of the probiotic level (p>0.05). In conclusion, inclusion of the prebiotic Alphamune can improve the nutrient efficiency and growth performance of rainbow trout confirming the positive effect of a mixture of prebiotics on fish

    Fishing pattern, maximum constant yield (MCY) and recruitment pattern of Thunnus tonggol in Hormuzgan province

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    Thunnus tonggol is one of the most important large pelagic fish species in Hormuzgan province waters. Nominal catch of T. tonggol in 2010 was 32405 tones comprising 65% of total catch of large pelagic fishes. For sustainable exploitation of the resources of this fish, we need to identify its fishing pattern, maximum constant yield and recruitment pattern. Hence, length and weight data were collected randomly from 6 major artisanal fish-landing sites Hassineh, Kong, Bandar Abbas, Salakh, Sirik and Jask in Hormuzgan province, starting in April 2010 over one year. Growth parameters L∞ and K were estimated at 112.23cm 0.3 and (1/year), respectively. Hence, the natural mortality was calculated at 0.43 (1/year) and the maximum constant yield was computed at 11880 tones. Length-weight power relationship, W= aFLb , was W= 3×10-05FL2.82 that showed T. tonggol have isometric growth. Fishing pattern indicated that almost 85% of the catch was under the size at first maturity. Maximum recruitment pattern was in November with average fork length being 27cm. For optimum exploitation of T. tonggol stocks, we suggest two approaches including fishing ban in the maximum recruitment time and gear (Drift gillnet) modification

    The Simultaneous Impacts of Seasonal Weather and Solar Conditions on PV Panels Electrical Characteristics

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    Solar energy usage is thriving day by day. These solar panels are installed to absorb solar energy and produce electrical energy. As a result, the efficiency of solar panels depends on different environmental factors, namely, air temperature, dust (aerosols and accumulated dust), and solar incidence, and photovoltaic panel angles. The effects of real conditions factors on power and efficiency of photovoltaic panels are studied in this paper through testing the panel in real environmental tests. To study the mentioned parameters precisely, two panels with different angles are used. The case study is regarding a region of Tehran, Iran, in summer and winter seasons. The results show that panel efficiency during winter is higher than summer due to air temperature decrement. It is discovered that among air pollutants, Al and Fe have the most share in polluting the air that affect the photovoltaic efficiency. Moreover, measuring the accumulated dust on the panels shows more amount in winter in comparison with summer. The important point in studying the effect of tilt angle is that inconformity between solar incidence and photovoltaic panel angles would result in solar radiation absorption and eventually panel efficiency loss and also, photovoltaic panel installation angle would affect the amount of dust deposited on its surface.© 2021 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https://creativecommons.org/licenses/by/4.0/).fi=vertaisarvioitu|en=peerReviewed
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