333 research outputs found

    The magic of the Last Planner® System for Nigerian construction

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    Extremely poor economic performance of the Nigerian construction industry suggests that non-value adding activities are prevalent, which result not only in the reduction of contractors’ profit margin but economic loss for the country in general. This study analyses non-value adding activities in Nigerian construction sites. The research seeks to establish potential antidotes within the Last Planner® System (LPS) and reveal the elements of the LPS which could be abstracted into Nigerian construction to improve performance. It was found that these elements form the theoretical basis for developing a lean approach that was labelled Last Planner® thinking

    D3-brane Potentials from Fluxes in AdS/CFT

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    We give a comprehensive treatment of the scalar potential for a D3-brane in a warped conifold region of a compactification with stabilized moduli. By studying general ultraviolet perturbations in supergravity, we systematically incorporate `compactification effects' sourced by supersymmetry breaking in the compact space. Significant contributions to the D3-brane potential, including the leading term in the infrared, arise from imaginary anti-self-dual (IASD) fluxes. For an arbitrary Calabi-Yau cone, we determine the most general IASD fluxes in terms of scalar harmonics, then compute the resulting D3-brane potential. Specializing to the conifold, we identify the operator dual to each mode of flux, and for chiral operators we confirm that the potential computed in the gauge theory matches the gravity result. The effects of four-dimensional curvature, including the leading D3-brane mass term, arise directly from the ten-dimensional equations of motion. Furthermore, we show that gaugino condensation on D7-branes provides a local source for IASD flux. This flux precisely encodes the nonperturbative contributions to the D3-brane potential, yielding a promising ten-dimensional representation of four-dimensional nonperturbative effects. Our result encompasses all significant contributions to the D3-brane potential discussed in the literature, and does so in the single coherent framework of ten-dimensional supergravity. Moreover, we identify new terms with irrational scaling dimensions that were inaccessible in prior works. By decoupling gravity in a noncompact configuration, then systematically reincorporating compactification effects as ultraviolet perturbations, we have provided an approach in which Planck-suppressed contributions to the D3-brane effective action can be computed.Comment: 70 page

    Association Between a Directly Translated Cognitive Measure of Negative Bias and Self-reported Psychiatric Symptoms

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    BACKGROUND: Negative interpretation biases are thought to be core symptoms of mood and anxiety disorders. However, prior work using cognitive tasks to measure such biases is largely restricted to case-control group studies, which cannot be used for inference about individuals without considerable additional validation. Moreover, very few measures are fully translational (i.e., can be used across animals and humans in treatment-development pipelines). This investigation aimed to produce the first measure of negative cognitive biases that is both translational and sensitive to individual differences, and then to determine which specific self-reported psychiatric symptoms are related to bias. METHODS: A total of 1060 (n = 990 complete) participants performed a cognitive task of negative bias along with psychiatric symptom questionnaires. We tested the hypothesis that individual levels of mood and anxiety disorder symptomatology would covary positively with negative bias on the cognitive task using a combination of computational modeling of behavior, confirmatory factor analysis, exploratory factor analysis, and structural equation modeling. RESULTS: Participants with higher depression symptoms (β = −.16, p = .017) who were older (β = −.11, p = .001) and had lower IQ (β = .14, p < .001) showed greater negative bias. Confirmatory factor analysis and structural equation modeling suggested that no other psychiatric symptom (or transdiagnostic latent factor) covaried with task performance over and above the effect of depression, while exploratory factor analysis suggested combining depression/anxiety symptoms in a single latent factor. Generating groups using symptom cutoffs or latent mixture modeling recapitulated our prior case-control findings. CONCLUSIONS: This measure, which uniquely spans both the clinical group-to-individual and preclinical animal-to-human generalizability gaps, can be used to measure individual differences in depression vulnerability for translational treatment-development pipelines

    Anomaly Equations and Intersection Theory

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    Six-dimensional supergravity theories with N=(1,0) supersymmetry must satisfy anomaly equations. These equations come from demanding the cancellation of gravitational, gauge and mixed anomalies. The anomaly equations have implications for the geometrical data of Calabi-Yau threefolds, since F-theory compactified on an elliptically fibered Calabi-Yau threefold with a section generates a consistent six-dimensional N=(1,0) supergravity theory. In this paper, we show that the anomaly equations can be summarized by three intersection theory identities. In the process we also identify the geometric counterpart of the anomaly coefficients---in particular, those of the abelian gauge groups---that govern the low-energy dynamics of the theory. We discuss the results in the context of investigating string universality in six dimensions.Comment: 29 pages + appendices, 8 figures; v2: minor corrections, references added; v3: minor corrections, reference adde

    Comparison of Statistical Models Used for Assessing Factors Associated with Infant Mortality in Nigeria

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    Background: Infant mortality is a public health concern especially in developing countries, particularly Nigeria. Different models had been used independently to identify factors associated with infant mortality. Some of the used models sometimes violate the underlying assumption for the models. This study was designed to compare the models that have been previously used and identify the appropriate model using standard model selection criteria to analyse risk factors for infant mortality in Nigeria. Methods: The study utilised 2008 Nigeria Demographic and Health Survey (NDHS) data with a sample size of 7107. The NDHS was a stratified two-stage cluster design where a questionnaire was used to collect data on the birth history of women aged 15-49 years. The models employed for this study were: Logit, Probit and Clog-log. The model selection criteria were Akaike Information Criterion (AIC), Residual Deviance and Vuong test. The model with the smallest criteria was considered to be the best fit. Results: The results showed that Infant Mortality in Nigeria can be appropriately modelled by Clog-log model. The models and corresponding AIC values were: Logit (6171.1), Probit (6212.6) and Clog-log (6126.6). The residual deviance included: Logit (6135.1), Probit (6176.6) and Clog-log (6090.6). Clog-log had the smallest AIC and residual deviance values; hence, it was of the best fit. Home delivery and delivery by professionals had negative significant associations with infant mortality while women's education (primary/no education) and birth order had positive significant association, (p < 0.05). Conclusion: The best model for infant mortality evaluation in Nigeria was Clog-log. Generally, improved women’s education would significantly reduce Infant Mortality in Nigeria

    Psychotic-like experiences and their cognitive appraisal under short-term sensory deprivation.

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    This study aimed to establish and compare the effects of brief sensory deprivation on individuals differing in trait hallucination proneness

    A comparative assessment of public and private dots laboratories in the Lagos state TB control programme

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    Background: The purpose of the laboratory services within the framework of the NTP is to provide bacteriologic evidence for the diagnosis, follow-up of TB patients and to document cure at the end of treatment. However to be fully functional, laboratory commodities should be available as needed. This study compared the laboratory hygiene practices and availability of laboratory equipment and other consumables for making diagnosis of TB in public and private DOTS laboratories in Lagos State.Methods: A descriptive comparative cross sectional study comparing availability of commodities in public and private laboratories involved in TB services in Lagos State.Results: Seventeen DOTS laboratories and 34 laboratory scientist/technician were recruited for this study. About three quarter and two thirds of the public and private DOTS laboratories respectively had reagents for smear microscopy. A significantly higher proportion of the public DOTS laboratories had separate area for TB work and separate table for smear preparation (p &lt;0.05). A higher proportion (71.4%) of the laboratory scientist/ technicians at the public compared with 38.5% of those at the private DOTS laboratories had good knowledge of the laboratory diagnosis of TB.Conclusion: Laboratories involved in TB service are not functioning optimally and need to be strengthened.Key Words: Laboratory, DOTS, Consumables, Hygiene.French AbstractContexte : L’objet des services des laboratoires dans le cadre du NTP est de fournir les preuves bactériologiques pour le diagnostic, de suivre les patients tuberculeux et de documenter la guérison a la fin du traitement. Toutefois, pour être pleinement fonctionnel, les produits de laboratoire devraient être disponibles au besoin. Cette recherche comparait les pratiques hygiènes de laboratoire et la disponibilité des équipements de laboratoire et autres consommables pour faire le diagnostic de la tuberculose aux laboratoires de DOTS publics et prives dans l’État de Lagos.Méthodes : Une étude transversale comparative et transversale descriptive comparant la disponibilité des produits aux laboratoires publics et prives  concernes a fournir aux services tuberculeux dans l’état de Lagos.Résultats : Dix – sept laboratoires de DOTS et 34 scientifiques/techniciens ont été recrutés pour cette recherche. Environ trois quarts et deux tiers des laboratoires de DOT publics et prives ont eu réactif respectivement pour la microscopie des frottis. Une proportion significativement plus élevée des laboratoires de DOTS publics a eu un espace séparé pour les travaux de la tuberculose et une table séparée pour la préparation des frottis (p&lt;0,05). Une proportion élevée(71,4%) des scientifiques/techniciens des laboratoires publics comparativement a 38,5% de ceux des laboratoires de DOTS prives avaient une bonne connaissance de diagnostic laboratoire de la tuberculose.Conclusion : Les laboratoires qui ont concerné a fournir les services tuberculeux ne fonctionnent pas de la façon optimale et doivent être renforcés.Mots– clés : Laboratoire, DOTS, consommables, Hygiène

    Cellulase recycling in biorefineriesis : is it possible?

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    On a near future, bio-based economy will assume a key role in our lives. Lignocellulosic materials (e.g., agroforestry residues, industrial/solid wastes) represent a cheaper and environmentally friendly option to fossil fuels. Indeed, following suitable processing, they can be metabolized by different microorganisms to produce a wide range of compounds currently obtained by chemical synthesis. However, due to the recalcitrant nature of these materials, they cannot be directly used by microorganisms, the conversion of polysaccharides into simpler sugars being thus required. This conversion, which is usually undertaken enzymatically, represents a significant part on the final cost of the process. This fact has driven intense efforts on the reduction of the enzyme cost following different strategies. Here, we describe the fundamentals of the enzyme recycling technology, more specifically, cellulase recycling. We focus on the main strategies available for the recovery of both the liquid- and solid-bound enzyme fractions and discuss the relevant operational parameters (e.g., composition, temperature, additives, and pH). Although the efforts from the industry and enzyme suppliers are primarily oriented toward the development of enzyme cocktails able to quickly and effectively process biomass, it seems clear by now that enzyme recycling is technically possible.Financial support from FEDER and Fundação para a Ciência e a Tecnologia (FCT): GlycoCBMs Project PTDC/AGR-FOR/3090/2012–FCOMP-01-0124- FEDER-027948 and Strategic Project PEst-OE/EQB/LA0023/2013, Project BBioInd-Biotechnology and Bioengineering for improved Industrial and Agro-Food processes, REF. NORTE-07-0124-FEDER-000028 Cofunded by the Programa Operacional Regional do Norte (ON.2–O Novo Norte), QREN, FEDER and the PhD grant to DG (SFRH/BD/88623/ 2012) and ACR (SFRH/BD/89547/2012)

    Stronger Neural Modulation by Visual Motion Intensity in Autism Spectrum Disorders

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    Theories of autism spectrum disorders (ASD) have focused on altered perceptual integration of sensory features as a possible core deficit. Yet, there is little understanding of the neuronal processing of elementary sensory features in ASD. For typically developed individuals, we previously established a direct link between frequency-specific neural activity and the intensity of a specific sensory feature: Gamma-band activity in the visual cortex increased approximately linearly with the strength of visual motion. Using magnetoencephalography (MEG), we investigated whether in individuals with ASD neural activity reflect the coherence, and thus intensity, of visual motion in a similar fashion. Thirteen adult participants with ASD and 14 control participants performed a motion direction discrimination task with increasing levels of motion coherence. A polynomial regression analysis revealed that gamma-band power increased significantly stronger with motion coherence in ASD compared to controls, suggesting excessive visual activation with increasing stimulus intensity originating from motion-responsive visual areas V3, V6 and hMT/V5. Enhanced neural responses with increasing stimulus intensity suggest an enhanced response gain in ASD. Response gain is controlled by excitatory-inhibitory interactions, which also drive high-frequency oscillations in the gamma-band. Thus, our data suggest that a disturbed excitatoryinhibitory balance underlies enhanced neural responses to coherent motion in ASD

    Therapies to limit myocardial injury in animal models of myocarditis: a systematic review and meta-analysis

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    Current myocarditis guidelines do not advocate treatment to prevent myocardial injury and scar deposition in patients with myocarditis and normal left ventricular ejection fraction. We aimed to ascertain the utility of beta blockers, calcium channel blockers and antagonists of the renin–angiotensin system in ameliorating myocardial injury, scar formation and calcification in animal in vivo models of myocarditis. The project was prospectively registered with the PROSPERO database of systematic reviews (CRD42018089336). Primary outcomes (necrosis, fibrosis and calcification) were meta-analysed with random-effects modelling. 52 studies were systematically reviewed. Meta-analysis was performed compared with untreated controls. In each study, we identified all independent comparisons of treatment versus control groups. The pooled weighted mean difference (WMD) indicated treatment reduced necrosis by 16.9% (71 controlled analyses, 95% CI 13.2–20.7%; P < 0.001), however there was less evidence of an effect after accounting for publication bias. Treatment led to a 12.8% reduction in fibrosis (73 controlled analyses, 95% CI 7.6–18.0%; P < 0.001). After accounting for publication bias this was attenuated to 7.8% but remained significant. Treatment reduced calcification by 4.1% (28 controlled analyses, 95% CI 0.2–8.0%; P < 0.0395). We observed significant heterogeneity in effect size in all primary endpoints, which was predominantly driven by differences between drug categories. Beta blockers and angiotensin-converting enzyme (ACE) inhibitors were the only agents that were effective for both necrosis and fibrosis, while only ACE inhibitors had a significant effect on calcification. This study provides evidence for a role for ACE inhibitors and beta blockers to prevent myocardial injury and scar deposition in in vivo models of myocarditis. There is a need for further well-designed studies to assess the translational application of these treatments
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