3,310 research outputs found
Development And Validation Of Parent Action Measurement Model
Kajian bertumpu pada pembinaan dan pengesahan instrumen SPAQ yang bertujuan
untuk mengesan konstruk tindakan ibu bapa yang mempunyai impak terhadap
pencapaian akademik dan disiplin pelajar di Malaysia.
The present research is aimed at developing and validating an instrument (SPAQ) to
measure the impact of parents’ actions on students’ academic achievement and
discipline in Malaysia. A survey using SPAQ was administered to 3425 secondary
school students of various races from 24 schools in Kedah, Penang and Perak
Factors Influencing Electronic Data Interchange (EDI) Usage In Port Related Industries In Northern Malaysia
Recent developments in Electronic Data Interchange (EDI) usage for container terminals examine the various benefits of its applications in the port environment. This report provides an early analysis of EDI developments in the
area. In a global context, ports are often very important maritime business centres where the most important commercial actors operate. Hence, ports are very important information centres. It can be either the driving force or the brakes of regional and local economies. It has been recognized as catalysts to spur the economic prosperity of a nation. Thereby, ports must be considered as a logistic and commercial platform. The maritime and port scenario is a fast growing one, especiahy in the areas of containerised cargo and short sea shipping. Ports are point of arrival and departure for this type of traffic and many of them are not yet able to match an acceptable operation performance. New challenges such as a need of quick loading/unloading operations and extremely fast administrative procedures are critical issues to look upon.
It is with these reasons that this study was conducted with the primary objective to identify factors that would contribute towards encouraging EDI usage besides cushioning its barriers. However the scope of the study is
restricted to those port related organizations in the Northern Region of Malaysia only. Among the key factors identified in this study that indicate a positive association to EDI usage are Competitive Pressure, Productivity Pressure, and Security aspects. Surprisingly, top-level support, vendors related factors and economic factors which were tested was found to have no significant
contribution to EDI usage. However, a closer look at the mean value showed that generally thereis a need to gain support from the top management and more aggressive promotion by vendors in order to ensure a more successful
implementation. This study suggested that vendors could play an active role in providing the expertise. In addition, understanding of information technoiogy is
important for successful implementation. For this, adequate training for both employees and management should be encouraged. Another suggestion is to introduce special scheme or programme in the form of incentives, grants,
subsidies, etc. to all the players involved in the promotion of information technology such as EDI in the 200 odd port related organizations
New immunolatex spheres: visual markers of antigens on lymphocytes for scanning electron microscopy
New immunochemical reagents consisting of antibodies bound to small latex spheres were used as visual markers for the detection and localization of cell surface antigens by scanning electron microscopy. Cross-linked latex spheres of various sizes from 300 to 3,4000 Å in diameter were synthesized by aqueous emulsion copolymerization of methacrylate derivatives containing hydroxyl and carboxyl functional groups. Proteins and other molecules containing primary amino groups were covalently bonded to the acrylic spheres under a variety of mild conditions by the aqueous carbodiimide, cyanogen bromide, and glutaraldehyde methods. For use in the indirect immunochemical-labeling technique, goat antibodies directed against rabbit immunoglobulins were bonded to the spheres. These immunolatex reagents were shown to bind only to cells (red blood and lymphocytes) which had previously been sensitized with rabbit antibodies against cell surface antigens. Mouse spleen lymphocytes with exposed immunoglobulins on their surface (B cells) were labeled with these spheres and distinguished from unlabeled or T lymphocytes by scanning electron microscopy. The distribution of Ig receptors on lymphocytes was also studied using the spheres as visual markers. When lymphocytes were fixed with glutaraldehyde and subsequently labeled with the immunolatex reagents, a random distribution was observed by scanning electron microscopy; a patchy distribution was observed when unfixed lymphocytes were used. These results are consistent with studies using ferritin-labeled antibodies (S. De Petris and M. Raff. 1973. Nature [Lond.]. 241:257.) and support the view that Ig receptors on lymphocytes undergo translational diffusion. In addition to serving as visual markers for scanning electron microscopy, these latex spheres tagged with fluorescent or radioactive molecules have applications as highly sensitive markers for fluorescent microscopy and as reagents for quantitative studies of cell surface antigens and other receptors
Complements and Meat Demand in the U.S.
In this study we estimated the price elasticities among meats, vegetables, grains, and potatoes and the impact that different levels of income have on the demand for these commodities. The 2005 Nielsen retail home scan data were used to construct a censored demand system of 14 equations. Results revealed that the uncompensated cross-price elasticities for both low and high-incomes suggest both substitution and complement relationships, while the compensated price elasticities are dominated primarily by substitution relationships. Our findings also revealed that expenditure elasticities among both low and high-income households differ for most commodities.censored dependent variables, meats, poultry, fish, vegetables, sample selection model, two-step estimation, Demand and Price Analysis, Livestock Production/Industries, C25, D12, Q11,
Songbird organotypic culture as an in vitro model for interrogating sparse sequencing networks
Sparse sequences of neuronal activity are fundamental features of neural circuit computation; however, the underlying homeostatic mechanisms remain poorly understood. To approach these questions, we have developed a method for cellular-resolution imaging in organotypic cultures of the adult zebra finch brain, including portions of the intact song circuit. These in vitro networks can survive for weeks, and display mature neuron morphologies. Neurons within the organotypic slices exhibit a diversity of spontaneous and pharmacologically induced activity that can be easily monitored using the genetically encoded calcium indicator GCaMP6. In this study, we primarily focus on the classic song sequence generator HVC and the surrounding areas. We describe proof of concept experiments including physiological, optical, and pharmacological manipulation of these exposed networks. This method may allow the cellular rules underlying sparse, stereotyped neural sequencing to be examined with new degrees of experimental control
An efficient algorithmic approach for mass spectrometry-based disulfide connectivity determination using multi-ion analysis
<p>Abstract</p> <p>Background</p> <p>Determining the disulfide (S-S) bond pattern in a protein is often crucial for understanding its structure and function. In recent research, mass spectrometry (MS) based analysis has been applied to this problem following protein digestion under both partial reduction and non-reduction conditions. However, this paradigm still awaits solutions to certain algorithmic problems fundamental amongst which is the efficient matching of an exponentially growing set of putative S-S bonded structural alternatives to the large amounts of experimental spectrometric data. Current methods circumvent this challenge primarily through simplifications, such as by assuming only the occurrence of certain ion-types (<it>b</it>-ions and <it>y</it>-ions) that predominate in the more popular dissociation methods, such as collision-induced dissociation (<it>CID</it>). Unfortunately, this can adversely impact the quality of results.</p> <p>Method</p> <p>We present an algorithmic approach to this problem that can, with high computational efficiency, analyze multiple ions types (<it>a</it>, <it>b</it>, <it>b<sup>o</sup>, b<sup>*</sup>, c</it>, <it>x</it>, <it>y, y<sup>o</sup>, y<sup>*</sup>,</it> and <it>z</it>) and deal with complex bonding topologies, such as inter/intra bonding involving more than two peptides. The proposed approach combines an approximation algorithm-based search formulation with data driven parameter estimation. This formulation considers only those regions of the search space where the correct solution resides with a high likelihood. Putative disulfide bonds thus obtained are finally combined in a globally consistent pattern to yield the overall disulfide bonding topology of the molecule. Additionally, each bond is associated with a confidence score, which aids in interpretation and assimilation of the results.</p> <p>Results</p> <p>The method was tested on nine different eukaryotic Glycosyltransferases possessing disulfide bonding topologies of varying complexity. Its performance was found to be characterized by high efficiency (in terms of time and the fraction of search space considered), sensitivity, specificity, and accuracy. The method was also compared with other techniques at the state-of-the-art. It was found to perform as well or better than the competing techniques. An implementation is available at: <url>http://tintin.sfsu.edu/~whemurad/disulfidebond</url>.</p> <p>Conclusions</p> <p>This research addresses some of the significant challenges in MS-based disulfide bond determination. To the best of our knowledge, this is the first algorithmic work that can consider multiple ion types in this problem setting while simultaneously ensuring polynomial time complexity and high accuracy of results.</p
In vitro and in vivo studies of the trypanocidal properties of WRR-483 against Trypanosoma cruzi.
BackgroundCruzain, the major cysteine protease of Trypanosoma cruzi, is an essential enzyme for the parasite life cycle and has been validated as a viable target to treat Chagas' disease. As a proof-of-concept, K11777, a potent inhibitor of cruzain, was found to effectively eliminate T. cruzi infection and is currently a clinical candidate for treatment of Chagas' disease.Methodology/principal findingsWRR-483, an analog of K11777, was synthesized and evaluated as an inhibitor of cruzain and against T. cruzi proliferation in cell culture. This compound demonstrates good potency against cruzain with sensitivity to pH conditions and high efficacy in the cell culture assay. Furthermore, WRR-483 also eradicates parasite infection in a mouse model of acute Chagas' disease. To determine the atomic-level details of the inhibitor interacting with cruzain, a 1.5 A crystal structure of the protease in complex with WRR-483 was solved. The structure illustrates that WRR-483 binds covalently to the active site cysteine of the protease in a similar manner as other vinyl sulfone-based inhibitors. Details of the critical interactions within the specificity binding pocket are also reported.ConclusionsWe demonstrate that WRR-483 is an effective cysteine protease inhibitor with trypanocidal activity in cell culture and animal model with comparable efficacy to K11777. Crystallographic evidence confirms that the mode of action is by targeting the active site of cruzain. Taken together, these results suggest that WRR-483 has potential to be developed as a treatment for Chagas' disease
Small, porous polyacrylate beads
Uniformly-shaped, porous, round beads are prepared by the co-polymerization of an acrylic monomer and a cross-linking agent in the presence of 0.05 to 5% by weight of an aqueous soluble polymer such as polyethylene oxide. Cross-linking proceeds at high temperature above about 50.degree.C or at a lower temperature with irradiation. Beads of even shape and even size distribution of less than 2 micron diameter are formed. The beads will find use as adsorbents in chromatography and as markers for studies of cell surface receptors
Crosslinked, porous, polyacrylate beads
Uniformly-shaped, porous, round beads are prepared by the co-polymerization of an acrylic monomer and a cross-linking agent in the presence of 0.05 to 5% by weight of an aqueous soluble polymer such as polyethylene oxide. Cross-linking proceeds at high temperature above about 50.degree.C or at a lower temperature with irradiation. Beads of even shape and even size distribution of less than 2 micron diameter are formed. The beads will find use as adsorbents in chromatography and as markers for studies of cell surface receptors
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