Greenhouse technology for sustainable production in mild winter climate areas: Trends and needs

Greenhouse production in the near future will need to reduce significantly its environmental impact. For this purpose, elements such as the structure, glazing materials, climate equipments and controls have to be developed and wisely managed to reduce the dependence on fossil fuels, achieve maximum use of natural resources such as solar radiation and water, and minimize the input of chemicals and fertilizers. This paper discusses the most relevant developments in greenhouse technology for mild winter climates. Regarding greenhouse structures, recent studies based on computational fluid dynamics have been conducted to investigate the effect of parameters such as ventilator size and arrangement, roof slope and greenhouse width and height on the air exchange rate. Next generation greenhouses are expected to incorporate some of the innovations derived from recent ventilation studies. Covering crops with screens is becoming a common practice. Main advantages and limitations of screenhouses are discussed in this paper. Thermal storage is increasingly applied in closed or semi-closed greenhouses. Under some conditions semi-closed greenhouses could mitigate day/night while reducing the use of water and the entrance of pest. Photo selective films that reflect a fraction of NIR radiation are effective at lowering greenhouse temperature and, in some cases, may be cost effective. NIR reflective films have side effects of major importance in greenhouse production. The CO2 enrichment strategy in computer-controlled greenhouses is based on determining the benefits of increasing the CO2 concentration against the cost of it. No clear strategies have been defined for the application of CO2 in unheated greenhouses, where most of the time the source of carbon dioxide is the external air. Some authors suggest ventilating as little as possible and fertilizing with bottled carbon dioxide at least up to the external concentration. Improving greenhouses by introducing new technologies may have an additional impact on the environment. From an environmental point of view, the incorporation of technology needs to increase yield to compensate for its associated environmental burden. Previous results have shown that forced ventilation and heating are the main reasons for the increase in environmental impact in climate controlled greenhouses. Additional results on the area of technology and its associated impact are discussed in this pape

Asymmetric Search and Loss Aversion: Choice Experiment on Consumer Willingness to Search in the Gasoline Retail Market

Price search enables consumers to overcome information asymmetries, it can lead to a reduction in price dispersion and it can increase consumer surplus, but search is costly. In this paper, an internet survey is conducted among a random sample of 490 drivers in the State of Ohio to answer the question, when are consumers more likely to search? The internet survey affords us the opportunity to impose exogenous price changes in a random sample of gasoline consumers to examine the decision-making process behind intended search decisions. Results indicate that among the respondents who faced prices below their expected price, only 12% chose to search, whereas 45% searched when prices were above. Results suggest that asymmetric search can be explained by prospect theory, in the sense that consumers evaluate current prices compared to a reference price, and as a consequence they value price increases differently from price decreases. Our findings indicate that in the gasoline retail market, consumers are allowing retailers to extract consumer surplus by exhibiting loss aversion because this behavior deters search when the probability of finding a lower price is highest.price search, choice experiment, search cost, gasoline market, Consumer/Household Economics, Demand and Price Analysis, D83, D03,

Multivectorial strategy to interpret a resistive behaviour of loads in smart buildings

In Smart buildings, electric loads are affected by an important distortion in the current and voltage waveforms, caused by the increasing proliferation of non linear electronic devices. This paper presents an approach on non sinusoidal power theory based on Geometric Algebra that clearly improves traditional methods in the optimization of apparent power and power factor compensation. An example is included that demonstrates the superiority of this approach compared with traditional methods.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

Economic Capital and Hispanic Economically Disadvantaged Student Persistence at a Hispanic-Serving Institution

The purpose of this study was to examine the relationship between college persistence and family income, parental education level, and type of financial aid for first-time, full-time Hispanic economically disadvantaged students selected from a South Texas Hispanic-serving institution. The dependent variable, college persistence, was measured by completed college credit hours per academic year. Predictor variables included family income, collected from the Free Application for Federal Student Aid (FAFSA), and parental education level, collected from the FAFSA for Parent 1 and Parent 2, as provided, indicating level of schooling received. Type of financial aid was the category of aid received, such as grants, loans, scholarships, work-study, or other. A quantitative design was useful to examine the impact of family income, parental education level, and type of financial aid on college persistence for first-time, full-time college students attending a Hispanic-serving institution in South Texas. A multiple linear regression analysis was the statistic used to determine if there was a relationship between the dependent variable, college persistence, and the predictor variables: family income, parental education level, and type of financial aid. Testing for the null hypothesis occurred using a level of significance, or alpha level, of .05. The literature review includes a historical Hispanic population growth background, how researchers have historically measured persistence, Hispanic student persistence, understanding the college price, and loan debt impact. The theoretical framework comprised Tinto’s (1975) theory of student departure and Becker’s (1975) human capital theory. This study focused on the persistence section of the theory of student departure and the relationship between persistence and financial aid variables, with human capital theory used to tie the economic aspect of financial aid, particularly student loans, to student persistence. The results showed a relationship between persistence and family income, parental education level, and type of financial aid. The multiple linear regression, conducted independently for enrolled students for 4 academic years, showed grants and scholarships consistently among the top three contributing variables of the total variance in predicting persistence. All seven predictor variables were significant in the first year, with grants and scholarships the top two contributing variables to predict persistence. Six of the seven predictor variables were significant in the second year, with grants and scholarships the top two contributing variables to predict persistence and family income next; parental education level was not significant. In the third year, six of the seven predictor variables were significant, with grants and scholarships the top two contributing variables to predict persistence and family income next; parental education level was not significant. Seven predictor variables were significant in the fourth year, with grants and scholarships the top two contributing variables to predict persistence followed by scholarships. Work-study was not significant

Preferential associated anomalies in 818 cases of microtia in South america

The etiology of microtia remains unknown in most cases. The identification of patterns of associated anomalies (i.e., other anomalies that occur with a given congenital anomaly in a higher than expected frequency), is a methodology that has been used for research into the etiology of birth defects. We conducted a study based on cases of microtia that were diagnosed from more than 5 million live (LB)- and stillbirths (SB) examined in hospitals participating in ECLAMC (Latin American Collaborative Study of Congenital Malformations) between 1967 and 2009. We identified 818 LB and SB with microtia and at least one additional non-related major congenital anomaly (cases) and 15,969 LB and SB with two or more unrelated major congenital anomalies except microtia (controls). A logistic regression analysis was performed to identify the congenital anomalies preferentially associated with microtia. Preferential associations were observed for 10 congenital anomalies, most of them in the craniofacial region, including facial asymmetry, choanal atresia, and eyelid colobomata. The analysis by type of microtia showed that for anomalies such as cleft lip and palate, macrostomia, and limb reduction defects, the frequency increased with the severity of the microtia. In contrast, for other anomalies the frequency tended to be the same across all types of microtia. Based on these results we will integrate data on the developmental pathways related to preferentially associated congenital anomalies for future studies investigating the etiology of microtia.Fil: Luquetti, Daniela V.. University of Washington; Estados Unidos. Seattle Children’s Research Institute; Estados UnidosFil: Cox, Thimoty C.. Monash University; Australia. University of Washington; Estados UnidosFil: López Camelo, Jorge Santiago. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. CEMIC-CONICET. Centro de Educaciones Médicas e Investigaciones Clínicas "Norberto Quirno". CEMIC-CONICET.; ArgentinaFil: Dutra, Maria da Graça. Instituto Oswaldo Cruz; BrasilFil: Cunningham, Michael L.. University of Washington; Estados Unidos. Seattle Children’s Research Institute; Estados UnidosFil: Castilla, Eduardo Enrique. Centro de Educación Médica e Investigaciones Clínicas “Norberto Quirno”; Argentina. Instituto Oswaldo Cruz; Brasil. Instituto Nacional de Genética Médica Populacional; Brasi

Estoque de carbono em sistema de uso da terra em Rondônia.

Este trabalho teve como objetivo determinar sistemas de uso da terra praticados em Rondônia, que podem contribuir para o incremento do sequestro de carbono na fitomassa e no solo. Para medir o estoque de carbono, tomou-se como referência a floresta primária, que foi comparada com os seguintes sistemas de uso da da terra: capoeira natural; capoeira melhorada com espécies leguminosas (Inga edulis e Senna sieames); monocultivo de café; sistemas agroflorestais (café x bandarra; café x seringueira); pastagens tradicionais e pastagem manejada. A floresta primária estoca, em média, 188 t ha -1 de C, sendo que 148 t ha -1 está presente na fitomassa acima do solo.bitstream/item/77901/1/FOL-6097-0001.pd

Mammalia, Chiroptera, Molossidae, <i>Molossops temminckii</i> (Burmeister, 1854), and Vespertilionidae, <i>Eptesicus furinalis</i> (dOrbigny and Gervais, 1847): New locality record and distribution extension in Cordoba Province, Argentina

During a field trip to the Ramsar site “Bañados del Río Dulce y Laguna Mar Chiquita” we captured three specimensof Molossops temminckii (Burmeister, 1854) and two of Eptesicus furinalis (d’Orbigny and Gervais, 1847). Molossopstemminckii has a wide distribution in Argentina, but this new record represents the second mention of the species for theCordoba Province after 13 years. The specimens of E. furinalis represent the tenth record for Cordoba and the second for RíoPrimero Department. This new information reflects the scarcity of systematic studies on bats in Cordoba Province