333 research outputs found
The Development of Novel Anti-folates: An Ongoing Battle Against Resistance
The development of drug compounds begins with the identification of well-validated targets. Conserved in bacterial, fungal, and mammalian species, the folate biosynthetic pathway performs critical processes to promote nucleic acid synthesis and maintain cellular function. Medicinal chemists have targeted dihydrofolate reductase (DHFR), an essential enzyme in this metabolic process, for several years. In fact, anti-folates acting on this pathway have potential roles against infectious diseases. This project examines a para-substituted drug compound called UCP111E, which is directed against dangerous fungal species, like Candida albicans and Candida glabrata. Since crystal structures of C. albicans DHFR (CaDHFR) and C. glabrata DHFR (CgDHFR) with UCP111E have already been solved, the main objective is to now deduce the structure of human DHFR (huDHFR) with the drug compound.
Sample preparation procedures in this project used Qiagen EasyXtal 15-well trays to plate various conditions for crystallization. Buffer (i.e., Tris), salt (i.e., lithium sulfate), precipitant (i.e., PEG 4000), and additive (i.e., ethanol) remained constant for each well in the trays. However, non-volatile additives (i.e., 1,8-diaminooctane, strontium chloride, and calcium chloride) varied.
Steps to improve the conditions with 1,8-diaminooctane produced plate-like crystals, while strontium chloride formed hexagon-shaped crystals, and calcium chloride, crystal rods. Only crystals formed with 1,8-diaminooctane and calcium chloride were large enough to diffract. However, diffraction patterns revealed the presence of salt, rather than protein, in the structures. Future projects hope to continue optimizing conditions with strontium chloride and calcium chloride to crystallize the huDHFR/UCP111E complex
Conflict Management in Culturally Diverse Workplaces : A lower-level managerâs perspective
This study discusses the intercultural workplace conflict management from lower-level managerâs point of view. The main objective of this study is to better understand how managers can develop the intercultural conflict management skills. The sub-objectives are to analyse workplace conflicts in intercultural context, determine crucial intercultural managerial skills, and understand the role of the manager as an interpreter with supervisory duties. Studying the workplace conflicts through intercultural lenses is important to understand the causes of conflicts in culturally diverse settings. Identifying the crucial managerial skills for conflict management shows the areas that require more attention. Thus, understanding how intercultural conflicts are created help to analyse different conflict management strategies and explore managerâs role.
The theoretical background of the study follows the structure of culture-based social ecological conflict model and includes additional literature and theories related to the components. The empirical research is conducted by qualitative interviews of informants who meet the criteria. The semi-structured interviews of five informants were collected and transcribed. For the analysis of the data, thematic analysis method was selected.
The findings of this study indicate that conflicts occurring at culturally diverse workplaces were related to apparent functional differences, which makes cultural differences an enhancing factor rather than a cause of conflicts. The study supports that lower-level managers have an important role in intercultural conflict settings in intervening conflict situations through interpretation. Yet the managerial skills are rather underappreciated and require self-learning because of insufficient training for the position. What is expected from the manager differ between different actors. Thus, responsibilities of a manager are vaguely determined, and the task-effectiveness was found to be valued over relational-effectiveness. The role of the manager as an interpreter and intervener is changing with the experiences, which highlights the importance of learning in the field through trial and error.TÀssÀ tutkimuksessa kÀsitellÀÀn kulttuurienvÀlisten työpaikkakonfliktien hallintaa alemman tason johtajien nÀkökulmasta. Tutkimuksen pÀÀtavoitteena on ymmÀrtÀÀ paremmin, miten johtajat voivat kehittÀÀ kulttuurienvÀlisten konfliktien hallintataitoja. Alatavoitteina on analysoida työpaikkakonflikteja kulttuurienvÀlisessÀ kontekstissa, mÀÀrittÀÀ kulttuurienvÀliset johtamistaidot, jotka ovat ratkaisevia, ja ymmÀrtÀÀ johtajan rooli tulkkina, jolla on esimiestehtÀviÀ. Työpaikkakonfliktien tutkiminen kulttuurienvÀlisen nÀkökulman kautta on tÀrkeÀÀ, jotta voidaan ymmÀrtÀÀ konfliktien syitÀ kulttuurisesti erilaisissa ympÀristöissÀ. Konfliktinhallinnan kannalta ratkaisevien johtamistaitojen tunnistaminen osoittaa, mihin alueisiin on kiinnitettÀvÀ enemmÀn huomiota. NÀin ollen kulttuurienvÀlisten konfliktien syntymisen ymmÀrtÀminen auttaa analysoimaan erilaisia konfliktinhallintastrategioita ja tutkimaan johtajan roolia.
Tutkimuksen teoreettinen tausta noudattaa kulttuuripohjaisen sosiaalis-ekologisen konfliktimallin rakennetta, ja siihen sisÀltyy osiin liittyvÀÀ lisÀkirjallisuutta ja teorioita. Empiirinen tutkimus toteutetaan kriteerit tÀyttÀvien informanttien laadullisilla haastatteluilla. Viiden informantin puolistrukturoidut haastattelut kerÀttiin ja kirjoitettiin puhtaaksi. Aineiston analysointiin valittiin temaattinen analyysimenetelmÀ.
Tutkimuksen tulokset osoittavat, ettÀ kulttuurisesti erilaisissa työpaikoissa esiintyvÀt konfliktit liittyivÀt ilmeisiin toiminnallisiin eroihin, mikÀ tekee kulttuurieroista pikemminkin konflikteja lisÀÀvÀn tekijÀn kuin niiden syyn. Tutkimus tukee sitÀ, ettÀ alemman tason johtajilla on kulttuurienvÀlisissÀ konfliktiympÀristöissÀ tÀrkeÀ rooli puuttua konfliktitilanteisiin tulkinnan kautta. Johtamistaitoja kuitenkin arvostetaan melko vÀhÀn, ja ne edellyttÀvÀt itseopiskelua, koska tehtÀvÀÀn ei ole riittÀvÀsti koulutusta. Se, mitÀ johtajalta odotetaan, vaihtelee eri toimijoiden vÀlillÀ. NÀin ollen johtajan vastuut ovat epÀmÀÀrÀisesti mÀÀriteltyjÀ, ja tehtÀvÀn tehokkuus on arvotettu suhteelliseen tehokkuuteen nÀhden. Johtajan rooli tulkkina ja vÀlittÀjÀnÀ muuttuu kokemusten myötÀ, mikÀ korostaa kentÀllÀ kokeilujen ja erehdysten kautta tapahtuvan oppimisen merkitystÀ
Modelling value-added tax in the presence of multiproduction and differentiated exemptions
We develop a framework for economy-wide modelling of value-added tax systems. Our framework models a number of complexities of VAT systems as they are implemented by tax agencies. In particular, we model multiple rates, multiple exemptions, multiple degrees of refundability across commodity users, and multi-product enterprises. A detailed VAT framework is important for correct modelling of VAT within a general equilibrium model. Such a framework is also of value in correctly representing the distribution of indirect tax payments within the database of a general equilibrium model, a prerequisite of accurate welfare analysis. We use the model to analyse the effects of simplifying Vietnamâs complex VAT system. We simplify the system by moving from three tax rates to one budget-neutral rate, while also removing many discretionary exemptions.value added tax; dynamic CGE model; Vietnam; indirect tax reform
Travel to My Memory
Personal perception of beauty always changes over time. The repetitive circle of adopting the new thoughts and replacing the old ones is a natural process of human being
Towards a Rule-level Verification Framework for Property-Preserving Graph Transformations
International audienceWe report in this paper a method for proving that a graph transformation is property-preserving. Our approach uses a relational representation for graph grammar and a logical representation for graph properties with first-order logic formulas. The presented work consists in identifying the general conditions for a graph grammar to preserve graph properties, in particular structural properties. We aim to implement all the relevant notions of graph grammar in the Isabelle/HOL proof assistant in order to allow a (semi) automatic verification of graph transformation with a reasonable complexity. Given an input graph and a set of graph transformation rules, we can use mathematical induction strategies to verify statically if the transformation preserves a particular property of the initial graph. The main highlight of our approach is that such a verification is done without calculating the resulting graph and thus without using a transformation engine
A Precondition Calculus for Correct-by-Construction Graph Transformations
We aim at assisting developers to write, in a Hoare style, provably correct graph transformations expressed in the ALCQ Description Logic. Given a postcondition and a transformation rule, we compute the weakest precondition for developers. However, the size and quality of this formula may be complex and hard to grasp. We seek to reduce the weakest preconditionâs complexness by a static analysis based on an alias calculus. The refined precondition is presented to the developer in terms of alternative formulae, each one specifying a potential matching of the source graph. The developer chooses then the formulae that correspond to his intention to obtain finally a correct-byconstruction Hoare triple
HIGH SCHOOL STUDENTSâ PERCEPTIONS OF THE USE OF FACEBOOK-BASED E-PORTFOLIOS IN EFL WRITING: A CASE IN THE MEKONG DELTA, VIETNAM
Electronic portfolios (e-portfolios) have grown in popularity in ESL/EFL writing instruction for their contributions to studentsâ writing. However, selecting an electronic tool in e-portfolios is of concern to many researchers and teachers. The combination of Facebook and e-portfolios is a rather new implementation in educational research, especially in high school contexts. Therefore, the current research aimed at exploring (1) high school studentsâ perceptions of the use of Facebook-based e-portfolios in terms of their contributions in writing, and (2) problems in using Facebook-based e-portfolios in writing. Fifty grade 11 students at a high school in Soc Trang province, Vietnam participated in the research. Both quantitative and qualitative data were collected by using close-ended questionnaire and the interview. Prior to data collection, the students spent six weeks writing on Facebook close-typed groups. The results showed that the students highly appreciated the contributions of Facebook-based e-portfolios in terms of enhancing interaction, giving and receiving feedback, motivation and confidence in writing, writing skills, vocabulary, and grammar knowledge. No significant problems were found in using Facebook-based e-portfolios. The research is expected to shed light on implementing Facebook-based e-portfolios in improving the quality of teaching EFL/ESL writing in high school contexts. Article visualizations
MODĂLISATION DE PROCĂDĂS LOGICIELS Ă BASE DE PATRONS RĂUTILISABLES
This thesis investigates the reuse of software processes by an approach based on process patterns. The objective of our work is to make process patterns directly applicable in process modeling. The concept of process pattern is used to capture and reuse the proven solutions for recurring process problems. However, this attractive concept has still been poorly exploited due to the inadequate formalization and the lack of supporting methodology and tools. To promote the use of process patterns and reduce the modelling effort, we broaden the concept of process pattern for capturing various types of process knowledge at different abstract levels, and propose ways to reuse (semi-)automatically process patterns in process modelling. We define the process meta-model UML-PP to formalize the process pattern concept and the ways to apply patterns in process models. UML-PP allows describing the internal structure of a process pattern as well as the relations between process patterns, and enables the explicit representation of process patterns' applications in process models. We propose the meta-process PATPRO defining the modelling steps to elaborate a process model in UML-PP by reusing process patterns. To allow automated applications of process patterns, we define an operational semantics for the patterns reuse operators who carry out some tasks of the meta-process. We have developed the prototype PATPRO-MOD allowing to create and manage process patterns catalogues, and to elaborate process models in UML-PP by reusing (semi-)automatically process patterns.Cette thÚse est consacrée à la réutilisation de procédés par une approche à base de patrons de procédé. Le concept de patron de procédé a été introduit pour capitaliser et réutiliser des solutions éprouvées des problÚmes de procédés récurrents. Cependant cette approche est encore peu exploitée à cause du champ de définition limité, du manque de formalisation, de méthodologie et d'outils support. Pour promouvoir l'utilisation de patrons de procédé et réduire l'effort de modélisation, nous considérons le concept de patron de procédé à différents niveaux d'abstraction pour capturer divers types de connaissances sur les procédés, et proposons des moyens pour réutiliser de façon (semi-)automatique ces patrons dans la modélisation des procédés. Nous avons défini le méta-modÚle de procédé UML-PP pour formaliser le concept de patron de procédé et la maniÚre d'appliquer les patrons dans la modélisation de procédés. UML-PP permet de décrire la structure interne d'un patron de procédé ainsi que les relations entre patrons, et permet d'exprimer explicitement l'utilisation de patrons dans les modÚles de procédé. Nous proposons le méta-procédé PATPRO définissant une démarche de modélisation pour élaborer un modÚle de procédé UML-PP en réutilisant des patrons de procédé. Pour permettre une automatisation de l'application de patrons de procédé, nous définissons une sémantique opérationnelle des opérateurs de réutilisation de patrons qui réalisent l'imitation de patrons. Nous avons réalisé le prototype PATPRO-MOD permettant de créer et gérer des catalogues de patrons de procédé et d'élaborer des modÚles de procédé UML-PP en réutilisant semi-automatiquement des patrons prédéfinis
Coagulation of chitin production wastewater from shrimp scraps with by-product chitosan and chemical coagulants
[[abstract]]Chitin production wastewater contains nutrient-rich organic and mineral contents. Coagulation of the wastewater with a natural coagulant such as by-product chitosan would be an economical and environmentally friendly method of treatment. This study investigated the treatment efficiencies of a preliminary sedimentation process followed by coagulation. The removal efficiencies for wastewater parameters were evaluated and compared for coagulants including by-product chitosan, polyaluminum chloride, and polyacryamide. The evaluation was based on the removal of wastewater turbidity and other criteria, including tCOD, sCOD, TKN, NH4+âN, TP, TSS, calcium, and crude protein. The results showed that the preliminary sedimentation (before coagulation) can remove over 80% of turbidity and more than 93% of TSS at pH 4 in 30 min. At optimal conditions, when the ratio of crude protein and calcium was 4.95, by-product chitosan dose of 77.5 mg·Lâ1 and pH = 8.3, the wastewater characteristics changes were tCOD 23%, sCOD 32%, TKN and ammonium 25%, TP 90%, TSS 84%, Ca2+ 29%, and crude protein 25%. The residue recovered through coagulation consists of up to 55 mg·gâ1 crude protein, which is used for animal feed or crop fertilizer.[[sponsorship]]ç§æéš[[notice]]èŁæŁćź
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