4,166 research outputs found

    Effect of Adding Palm Fiber to Thermal Conductivity of Quick Set Concrete

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    As climate change becomes a more dire issue and more readily accepted by those in power, the demand for local and systemic solutions grows louder. In urban environments, one issue of concern is the contribution of anthropogenic heat from buildings which contributes to localized warming of the environment. A method that can reduce anthropogenic heat is decreasing the thermal conductivity of building materials. The objective of this study is to examine the possibility of using palm fibers to reduce the thermal conductivity of quick-set concrete samples. The data gathered in this study are used to determine the thermal conductivity value of samples with varying weight percentage content of palm fiber. These results lend evidence to the worth of exploring methods of using local sources of organic fibers to reduce the thermal conductivity of building materials which may help reduce anthropogenic heat from new building constructions. Based on the results of this study, adding palm fiber reduces the thermal conductivity of quick-set concrete samples

    On thick subcategories of the category of projective presentations

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    We study thick subcategories of the category of 2-term complexes of projective modules over an associative algebra. We show that those thick subcategories that have enough injectives are in explicit bijection with 2-term silting complexes and complete cotorsion pairs. We also provide a bijection with left finite wide subcategories of the module category and prove that all these maps are compatible with previously known correspondences. We discuss possible applications to stability conditions.Comment: 35 pages V2: typos corrected V3: new introduction for section 4, typos correcte

    A recipe for an unpredictable random number generator

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    In this work we present a model for computation of random processes in digital computers which solves the problem of periodic sequences and hidden errors produced by correlations. We show that systems with non-invertible non-linearities can produce unpredictable sequences of independent random numbers. We illustrate our result with some numerical calculations related with random walks simulations.Comment: 8 pages, 5 figures, Proceedings Mochima spring school in theoretial physic

    Identification and Characterization of the Lipid Transport System in the Tarantula Grammostola rosea

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    Lipids due to its hydrophobic nature are transported in the hemolymph mainly by lipoproteic fractions. In the present work we studied the lipoproteic fractions present in the hemolymph of the spider Grammostola rosea. Through ultracentrifugation two lipoproteic fractions are isolated, one of high density named Gr-HDL (δ = 1.13 - 1.15 g/ml) and the other of very high density called Gr-VHDL (δ = 1.24 - 1.27 g/ml) Gr-VHDL in hemolymph is majority in relation to Gr-HDL. In this sense Gr-VHDL fraction has 98.6% of hemolymphatic proteins, and 89.3% of lipids presents in the hemolymph. Both lipoproteic fractions possess phospholipids such as majority lipids (phosphatidylcholine and phosphatidylethanolamine) and 18:1, 16:0, 18:2 and 18:0 as the major fatty acids. In order to confirm the role played by lipoproteic fractions in vitro assays with different 14C-lipid were performed. It was observed that Gr-VHDL takes up mainly free fatty acids and triacylglycerols unlike that observed for Gr-HDL in relation to phosphatidylcholine. Through electrophoresis it was observed that Gr-VHDL has three proteins: a predominant band of 68 kDa and two others of 99 and 121 kDa. Gr-HDL displayed a predominant band of 93 kDa, and other minority of 249 kDa. In conclusion, this study reports lipid characterization of the lipoproteic fractions present in the hemolymph of the tarantula, G. rosea. The role of each lipoproteic fraction in relation to lipid up- take is sustained by in vitro assays. Similarities and differences are found when it is compared to lipoproteins of only the three species of spiders studied.Fil: Laino, Aldana. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Investigaciones Bioquímicas de La Plata ; ArgentinaFil: Cunningham, Monica Liliana. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Investigaciones Bioquímicas de La Plata ; ArgentinaFil: Suarez, Gustavo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Investigaciones Bioquímicas de La Plata ; ArgentinaFil: Garcia, Carlos Fernando. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Investigaciones Bioquímicas de La Plata ; Argentin

    Organizational Leadership in Academic Libraries : Identifying Culture Types and Leadership Roles

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    The purpose of this study is to identify organizational culture types and leadership roles among research and non-research libraries in higher education institutions in the United States and to reveal trends that can assist in enacting needed organizational change. Organizational culture and leadership are two intertwined concepts that are strongly aligned with the human element of any supervisory experience. According to Crosby, they help “nurture effective and humane organizations” (Crosby, 2004). This research project sought to test the claims brought forth by library researchers such as Kaarts-Brown et al. in which they reported a tie between the library manager’s ability to shift leadership roles to the overall effectiveness of the organization’s culture (2004, p. 38). It also examined possible models to aid libraries in diagnosing and making change that can influence organizational culture in positive ways. Application of Cameron and Quinn’s Competing Values Framework (CVF) by use of the Organizational Culture Assessment Instrument (OCAI) provided a method for identifying culture and leadership roles among 625 academic library respondents. One hundred higher education libraries affiliated with the Association of Research Libraries (ARL) were compared to 123 similar-sized non-research oriented colleges and universities. The library literature stresses that budgetary constraints cause great difficulties among libraries of all types in this country. It also states that library science education does little to prepare its leaders to tackle this wide-spread crisis. This research project attempted to reveal the impact budget may have on culture and if education has any bearing on leadership traits and if one library type displays cultures or leadership roles that are desirable. Significant differences were revealed for several of the variables studied. Revealing culture types or library organizations and the leadership roles of their chief officers can aid in the diagnosis of effective or ineffective organizations. Once types and roles are identified, strategies can be suggested to meet institutional goals in spite of budget problems. With no state-supported economic relief anticipated for higher education in the near future, identifying creative strategies for library directors to employ may aid them in becoming more effective managers. Cameron and Quinn assert that effective managers beget effective leaders, who in turn can invoke positive change within their organizations (2006, p. 81)

    The Ancient Mayan

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    Exploring the Mayan traditions, ways of communicating, and passed down beliefs in the Esquivel family tree. The homeland of Yucatan Peninsula a world known to the Mayan ruins. In this creative story a young woman discovers many important aspects of her life through her ancestors

    Funding, Supporting, & Sustaining OER

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    Before you approach the Administration or an external entity for financial support, get those ducks lined up on your campus! Faculty | Librarians | IT Support | Proposed Courses | Registrar

    Workplace Concentration of Immigrants

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    To what extent do immigrants and the native-born work in separate workplaces? Do worker and employer characteristics explain the degree of workplace concentration? We explore these questions using a matched employer-employee database that extensively covers employers in selected MSAs. We find that immigrants are much more likely to have immigrant coworkers than are natives, and are particularly likely to work with their compatriots. We find much higher levels of concentration for small businesses than for large ones, that concentration varies substantially across industries, and that concentration is particularly high among immigrants with limited English skills. We also find evidence that neighborhood job networks are strongly positively associated with concentration. The effects of networks and language remain strong when type is defined by country of origin rather than simply immigrant status. The importance of these factors varies by immigrant country of origin—for example, not speaking English well has a particularly strong association with concentration for immigrants from Asian countries. Controlling for differences across MSAs, we find that observable employer and employee characteristics account for about half of the difference between immigrants and natives in the likelihood of having immigrant coworkers, with differences in industry, residential segregation and English speaking skills being the most important factors
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