230 research outputs found

    Implementasi Profesionalisme Guru Dalam Memotivasi Belajar Siswa Di Sekolah Dasar

    Full text link
    Professionalism seems to develop at all sectors in Indonesia today. Many efforts have been undertaken by the decision makers of education to pursue it. Among other efforts done by the authorities is the professional teacher certification. The implementation of professional teacher certification has basically referred to the Law No. 19, year 2005, on the National Education Standard; and the Governmental Regulation No. 74 year 2008 on Teachers, which suggest that teachers are obliged to have relevant academic qualification, competence and certification of educator. The objective of those regulations is only very prestigious i.e. to make them enhance qualified working experience within a certain interval of time. Hopefully, after they are certified professionally, they are able to encourage students to learn, especially for elementary student

    Spectroscopy as a rapid detecting paprika powder adulteration

    Get PDF
    Paprika powder, a spice known for imparting flavour, colour and aroma in foods has recently become compromised by fraudulent activities involving diverse adulterants such as corn flour and has prompted quality assurance (QA) measures. Near infrared spectroscopy (NIRS) is a non-destructive method gaining grounds in QA applications. The study applied NIRS to detect paprika powder adulterated with corn flour. Chemometric evaluation spectra showed that NIRS could discriminate cornflour adulteration with 100% classification accuracy. Adulteration was also predicted with high accuracies coefficient of determination (R2CV) between 0.97 and 0.99 and low errors (0.72 g/100g), proving the future QA applications of NIRS

    A Condensation-Ordering Mechanism in Nanoparticle-Catalyzed Peptide Aggregation

    Get PDF
    Nanoparticles introduced in living cells are capable of strongly promoting the aggregation of peptides and proteins. We use here molecular dynamics simulations to characterise in detail the process by which nanoparticle surfaces catalyse the self- assembly of peptides into fibrillar structures. The simulation of a system of hundreds of peptides over the millisecond timescale enables us to show that the mechanism of aggregation involves a first phase in which small structurally disordered oligomers assemble onto the nanoparticle and a second phase in which they evolve into highly ordered beta-sheets as their size increases

    Are Long-Range Structural Correlations Behind the Aggregration Phenomena of Polyglutamine Diseases?

    Get PDF
    We have characterized the conformational ensembles of polyglutamine peptides of various lengths (ranging from to ), both with and without the presence of a C-terminal polyproline hexapeptide. For this, we used state-of-the-art molecular dynamics simulations combined with a novel statistical analysis to characterize the various properties of the backbone dihedral angles and secondary structural motifs of the glutamine residues. For (i.e., just above the pathological length for Huntington's disease), the equilibrium conformations of the monomer consist primarily of disordered, compact structures with non-negligible -helical and turn content. We also observed a relatively small population of extended structures suitable for forming aggregates including - and -strands, and - and -hairpins. Most importantly, for we find that there exists a long-range correlation (ranging for at least residues) among the backbone dihedral angles of the Q residues. For polyglutamine peptides below the pathological length, the population of the extended strands and hairpins is considerably smaller, and the correlations are short-range (at most residues apart). Adding a C-terminal hexaproline to suppresses both the population of these rare motifs and the long-range correlation of the dihedral angles. We argue that the long-range correlation of the polyglutamine homopeptide, along with the presence of these rare motifs, could be responsible for its aggregation phenomena

    Polyglutamine Induced Misfolding of Huntingtin Exon1 is Modulated by the Flanking Sequences

    Get PDF
    Polyglutamine (polyQ) expansion in exon1 (XN1) of the huntingtin protein is linked to Huntington's disease. When the number of glutamines exceeds a threshold of approximately 36–40 repeats, XN1 can readily form amyloid aggregates similar to those associated with disease. Many experiments suggest that misfolding of monomeric XN1 plays an important role in the length-dependent aggregation. Elucidating the misfolding of a XN1 monomer can help determine the molecular mechanism of XN1 aggregation and potentially help develop strategies to inhibit XN1 aggregation. The flanking sequences surrounding the polyQ region can play a critical role in determining the structural rearrangement and aggregation mechanism of XN1. Few experiments have studied XN1 in its entirety, with all flanking regions. To obtain structural insights into the misfolding of XN1 toward amyloid aggregation, we perform molecular dynamics simulations on monomeric XN1 with full flanking regions, a variant missing the polyproline regions, which are hypothesized to prevent aggregation, and an isolated polyQ peptide (Qn). For each of these three constructs, we study glutamine repeat lengths of 23, 36, 40 and 47. We find that polyQ peptides have a positive correlation between their probability to form a β-rich misfolded state and their expansion length. We also find that the flanking regions of XN1 affect its probability to^x_page_count=28 form a β-rich state compared to the isolated polyQ. Particularly, the polyproline regions form polyproline type II helices and decrease the probability of the polyQ region to form a β-rich state. Additionally, by lengthening polyQ, the first N-terminal 17 residues are more likely to adopt a β-sheet conformation rather than an α-helix conformation. Therefore, our molecular dynamics study provides a structural insight of XN1 misfolding and elucidates the possible role of the flanking sequences in XN1 aggregation

    The power to detect artificial selection acting on single loci in recently domesticated species

    Get PDF
    <p>Abstract</p> <p>Background</p> <p>An increasing number of aquaculture species are subjected to artificial selection in systematic breeding programs. Rapid improvements of important commercial traits are reported, but little is known about the effects of the strong directional selection applied, on gene level variation. Large numbers of genetic markers are becoming available, making it feasible to detect and estimate these effects. Here a simulation tool was developed in order to explore the power by which single genetic loci subjected to uni-directional selection in parallel breeding populations may be detected.</p> <p>Findings</p> <p>Two simulation models were pursued: 1) screening for loci displaying higher genetic differentiation than expected (high-F<sub>ST </sub>outliers), from neutral evolution between a pool of domesticated populations and a pool of wild populations; 2) screening for loci displaying lower genetic differentiation (low-F<sub>ST </sub>outliers) between domesticated strains than expected from neutral evolution. The premise for both approaches was that the isolated domesticated strains are subjected to the same breeding goals. The power to detect outlier loci was calculated under the following parameter values: number of populations, effective population size per population, number of generations since onset of selection, initial F<sub>ST</sub>, and the selection coefficient acting on the locus. Among the parameters investigated, selection coefficient, the number of generation since onset of selection, and number of populations, had the largest impact on power. The power to detect loci subjected to directional in breeding programmes was high when applying the between farmed and wild population approach, and low for the between farmed populations approach.</p> <p>Conclusions</p> <p>A simulation tool was developed for estimating the power to detect artificial selection acting directly on single loci. The simulation tool should be applicable to most species subject to domestication, as long as a reasonable high accuracy in input parameters such as effective population size, number of generations since the initiation of selection, and initial differentiation (F<sub>ST</sub>) can be obtained. Identification of genetic loci under artificial selection would be highly valuable, since such loci could be used to monitor maintenance of genetic variation in the breeding populations and monitoring possible genetic changes in wild populations from genetic interaction between escapees and their wild counterpart.</p

    Contrasted Patterns of Selection on MHC-Linked Microsatellites in Natural Populations of the Malagasy Plague Reservoir

    Get PDF
    Plague (Yersinia pestis infection) is a highly virulent rodent disease that persists in many natural ecosystems. The black rat (Rattus rattus) is the main host involved in the plague focus of the central highlands of Madagascar. Black rat populations from this area are highly resistant to plague, whereas those from areas in which the disease is absent (low altitude zones of Madagascar) are susceptible. Various lines of evidence suggest a role for the Major Histocompatibility Complex (MHC) in plague resistance. We therefore used the MHC region as a candidate for detecting signatures of plague-mediated selection in Malagasy black rats, by comparing population genetic structures for five MHC-linked microsatellites and neutral markers in two sampling designs. We first compared four pairs of populations, each pair including one population from the plague focus and one from the disease-free zone. Plague-mediated selection was expected to result in greater genetic differentiation between the two zones than expected under neutrality and this was observed for one MHC-class I-linked locus (D20Img2). For this marker as well as for four other MHC-linked loci, a geographic pattern of genetic structure was found at local scale within the plague focus. This pattern would be expected if plague selection pressures were spatially variable. Finally, another MHC-class I-linked locus (D20Rat21) showed evidences of balancing selection, but it seems more likely that this selection would be related to unknown pathogens more widely distributed in Madagascar than plague

    Cynomolgus Macaque as an Animal Model for Severe Acute Respiratory Syndrome

    Get PDF
    BACKGROUND: The emergence of severe acute respiratory syndrome (SARS) in 2002 and 2003 affected global health and caused major economic disruption. Adequate animal models are required to study the underlying pathogenesis of SARS-associated coronavirus (SARS-CoV) infection and to develop effective vaccines and therapeutics. We report the first findings of measurable clinical disease in nonhuman primates (NHPs) infected with SARS-CoV. METHODS AND FINDINGS: In order to characterize clinically relevant parameters of SARS-CoV infection in NHPs, we infected cynomolgus macaques with SARS-CoV in three groups: Group I was infected in the nares and bronchus, group II in the nares and conjunctiva, and group III intravenously. Nonhuman primates in groups I and II developed mild to moderate symptomatic illness. All NHPs demonstrated evidence of viral replication and developed neutralizing antibodies. Chest radiographs from several animals in groups I and II revealed unifocal or multifocal pneumonia that peaked between days 8 and 10 postinfection. Clinical laboratory tests were not significantly changed. Overall, inoculation by a mucosal route produced more prominent disease than did intravenous inoculation. Half of the group I animals were infected with a recombinant infectious clone SARS-CoV derived from the SARS-CoV Urbani strain. This infectious clone produced disease indistinguishable from wild-type Urbani strain. CONCLUSIONS: SARS-CoV infection of cynomolgus macaques did not reproduce the severe illness seen in the majority of adult human cases of SARS; however, our results suggest similarities to the milder syndrome of SARS-CoV infection characteristically seen in young children

    Deep Theorizing in International Relations

    Get PDF
    This paper starts from the observation that, at a time when the popularity of grand theory is in decline among IR scholars, they do not agree on what they mean by theory. In fact, the celebration of theoretical pluralism is accompanied by the relative absence of a serious conversation about what ‘theory’ is, could, or should be. Taking the view that we need such a conversation, this puts forward the notion of ‘deep theorizing’. Countering both the shallow theorizing of modern scholarship that conflates theory with scientific method, and the postmodern view that abstract narratives must be deconstructed and rejected, it offers a reading of the parameters along which substantial theorizing proceeds. Specifically, it suggests that ‘deep theorizing’ is the conceptual effort of explaining (inter)action by developing a reading of drives/basic motivations and the ontology of its carrier through an account of the human condition, that is, a particular account of how the subject (the political actor) is positioned in social space and time. The paper illustrates the plausibility of this meta-theoretical angle in a discussion of realist, liberal and postcolonial schools of thought

    Race at the margins: A Critical Race Theory perspective on race equality in UK planning.

    Get PDF
    Despite evidence of the growing ethnic diversity of British cities and its impact on urban governance, the issue of racial equality in UK planning remains marginal, at best, to mainstream planning activity. This paper uses Critical Race Theory (CRT) to consider the reasons why the ‘race’ and planning agenda continues to stall. CRT, it is argued, offers a compelling account of why changes in practice over time have been patchy at best, and have sometimes gone into reverse
    corecore