Academic achievement : the role of praise in motivating students

The motivation of students is an important issue in higher education, particularly in the context of the increasing diversity of student populations. A social-cognitive perspective assumes motivation to be dynamic, context-sensitive and changeable, thereby rendering it to be a much more differentiated construct than previously understood. This complexity may be perplexing to tutors who are keen to develop applications to improve academic achievement. One application that is within the control of the tutor, at least to some extent, is the use of praise. Using psychological literature the article argues that in motivating students, the tutor is not well served by relying on simplistic and common sense understandings of the construct of praise and that effective applications of praise are mediated by students' goal orientations, which of themselves may be either additive or interactive composites of different objectives and different contexts

New Insights on Long-Term Hepatitis B Virus Responses in HIV–Hepatitis B virus Co-infected Patients: Implications for Antiretroviral Management in Hepatitis B virus-Endemic Settings

BACKGROUND: WHO treatment guidelines recommend tenofovir plus lamivudine or emtricitabine as the nucleoside reverse transcriptase inhibitor backbone in first-line regimens for HIV-infected adults. Lamivudine alone is not recommended, because of the risk of hepatitis B virus (HBV) resistance. We studied HBV responses in a large cohort of co-infected patients in a resource-limited setting. SETTING: Clinical centers in Uganda and Zimbabwe. METHODS: DART was a randomized trial of monitoring practices in HIV-infected adults starting antiretroviral therapy. Baseline samples were tested retrospectively for HBV serological markers and HBV DNA. Longitudinal HBV DNA testing at 48 weeks and the last available sample before HBV-relevant modification of antiretroviral therapy was performed on patients with detectable HBV DNA at baseline. RESULTS: Two hundred twenty-four hepatitis B surface antigen-positive patients were followed for up to 4.8 years. Of the drugs with anti-HBV activity, 166 were prescribed lamivudine-tenofovir and 58 lamivudine alone. Ninety-eight percent (96/98) patients with baseline HBV DNA 6 log10 IU/mL. Of the 83 patients suppressed at 48 weeks and with follow-up data, only 7(8%) experienced viral rebound (range 200-3460 IU/mL). Of the 20 patients not suppressed at 48 weeks and with follow-up data, HBV DNA levels generally declined with lamivudine-tenofovir, but increased with lamivudine alone. Alanine transaminase flares were not observed in any patient who experienced viral rebound. CONCLUSIONS: The suppressive effect of lamivudine alone was highly durable (up to 5 years) in HIV-HBV co-infected patients with baseline HBV DNA <6 log10 IU/mL. It may be feasible to develop stratified approaches using lamivudine as the only drug with anti-HBV activity

Absence of Root Hairs in Non-Nodulating Groundnut, Arachis hypogaea L.

Root hairs observed at the site of lateral root emergence in nodulating groundnut cultivars were found to be absent in non-nodulating groundnut lines. In a segregating F2-population of the cross NC 17 × PI 259747 a strong association was observed between the presence of root hairs and nodulation, and the absence of root hairs and non-nodulation

Comparação de quatro métodos para a delimitação de uma microbacia hidrográfica de 1 km2: GRASS e extensões Spatial Analyst, ArcSWAT e HEC-GeoHMS no ArcGIS.

A correta delimitação de uma microbacia hidrográfica (MBH) é essencial para sua caracterização e gestão. Porém os métodos digitais de delimitação de bacias são pouco usados para delimitar MBH's. O trabalho comparou quatro métodos para a delimitação de uma MBH de uso agrícola de cerca de 1 km², no Paraná, a partir de um modelo digital de elevação SRTM com pixel de 30 m. Os métodos foram implementados nos programas GRASS e ArcGIS (usando as extensões Spatial Analyst, ArcSWAT e HEC-GeoHMS). Todas as MBH's foram satisfatoriamente delimitadas quando avaliadas usando um MDE com pixel de 1 m e curvas de nível extraídas dele. Entre os métodos, aquele aplicado no Spatial Analyst mostrou-se rápido e simples. O HEC-GeoHMS possui muitas etapas e detalhes, o que pode se tornar um incômodo. O GRASS utiliza o parâmetro quantidade mínima de células na bacia para delimitar, o que pode exigir muitas tentativas e erros até encontrar a quantidade correspondente à microbacia. O ArcSWAT calcula automaticamente diversos parâmetros das bacias delimitadas e dos rios, tais como área, perímetro, coordenadas geográficas e elevação. Diante disso, recomenda-se o uso do ArcSWAT por ser simples, gerar um bom delineamento e ainda calcular parâmetros das microbacias e dos rios

Nitrogen Fixation By Groundnut (Arachis Hypogaea) In Intercropped And Rotational Systems

This paper examines the nodulation and nitrogen furation of groundnut when grown in pure culture or in associatbn with pearl millet, maize or sorghum. In all cases, association of groundnut with a cereal resulted in reduced nodulation and nitrogen fixation. This was ascribed to shading of the groundnut, leading to reduced photosynthesis. When grain milkt was planted in rotation wish groundnut or maize supplied 21) kg N/ha, yield following .groundnut were 524 kg/ha greater than obtained in the millet] maize rotation

Genetic Manipulation Of Nodulation In Groundnut

There is large variation among cultivars of groundnut in ability to nodulatc and fix nitrogen (N), and in seasonal and diurnal patterns of nitrogenase activity. Total N uptake, or total dry matter production, may be a useful index in ranking cultivan for N2-fixing ability. Certain cultivars of Arachis hypogaea ssp. hypogaea var. bpogaea formed up to 13% of their total nodule number on the hypocotyl, and some cultivars even nodulated on the stem above the crown of the plant. In contrast, cultivars from A. hypogaea ssp. fastigiata var. fasrigiata and var. vulgaris formed few nodules on the. hypocotyl. Non-nodulating plants have been observed in 13 crosses. Genetic analysis indicates that two independent recessive genes are involved. Some progeny of these crosses also form a few big nodules, a trait which seems to be controlled by the host plant

Morfometria de bacias hidrográficas de primeira ordem em áreas agrícolas sob sistema plantio direto: delimitação e propensão à erosão e inundação.

O Sistema Plantio Direto (SPD) aplica técnicas agrícolas conservacionistas para preservação do solo, controlando processos de erosão. Para isso, é necessário conhecer as características do relevo que afetam a dinâmica e o poder erosivo da água na microbacia hidrográfica (MBH) em que o SPD está inserido. Os objetivos do trabalho foram: adaptar uma metodologia para o delineamento de 12 MBHs de cerca de 1 km² sob SPD a partir de modelos digitais de terreno (MDTs) e de elevação (MDEs). Ademais, calcularam-se quatro índices morfométricos relacionados à dinâmica e poder erosivo da água nas MBHs: declividade, coeficiente de compacidade (CC), índice de circularidade (IC) e fator de forma (FF). Para delimitar as MBHs foi necessário combinar dados de diferentes fontes e resoluções espaciais (MDTs Pleiades e Ultracam D, MDEs ALOS Palsar e SRTM) e usou-se a extensão ArcSWAT. As MBH estavam distribuídas nos seguintes estados: SP, GO, MS, RS e PR. Conforme os valores de declividade, as MBHs Sarandi e Coxilha são as mais propensas à erosão, enquanto Maracaju 1 e Itaí 1 são as menos propensas. Segundo os índices CC, IC e FF, as MBHs Toledo 2 e Coxilha são as mais propensas à inundação, e as MBHs Maracaju 1 e 2 e Itaí 1 as menos. A metodologia aplicada foi adaptada com êxito para a delimitação de MBHs de primeira ordem. Outrossim, os índices morfométricos calculados subsidiarão a gestão do SPD, permitindo executar medidas de controle da erosão, reduzindo impactos da perda de solo e nutrientes nessas áreas agrícolas

Nitrogen Fixation By Groundnut (Arachis Hypoga Ea) In Intercropped And Rotational Systems

This paper examines the nodulation and nitrogen furation of groundnut when grown in pure culture or in associatbn with pearl millet, maize or sorghum. In all cases, association of groundnut with a cereal resulted in reduced nodulation and nitrogen fixation. This was ascribed to shading of the groundnut, leading to reduced photosynthesis. When grain milkt was planted in rotation wish groundnut or maize supplied 21) kg N/ha, yield following .groundnut were 524 kg/ha greater than obtained in the millet] maize rotation

Evidence for Reduced Drug Susceptibility without Emergence of Major Protease Mutations following Protease Inhibitor Monotherapy Failure in the SARA Trial

BACKGROUND: Major protease mutations are rarely observed following failure with protease inhibitors (PI), and other viral determinants of failure to PI are poorly understood. We therefore characterized Gag-Protease phenotypic susceptibility in subtype A and D viruses circulating in East Africa following viral rebound on PIs. METHODS: Samples from baseline and treatment failure in patients enrolled in the second line LPV/r trial SARA underwent phenotypic susceptibility testing. Data were expressed as fold-change in susceptibility relative to a LPV-susceptible reference strain. RESULTS: We cloned 48 Gag-Protease containing sequences from seven individuals and performed drug resistance phenotyping from pre-PI and treatment failure timepoints in seven patients. For the six patients where major protease inhibitor resistance mutations did not emerge, mean fold-change EC50 to LPV was 4.07 fold (95% CI, 2.08-6.07) at the pre-PI timepoint. Following viral failure the mean fold-change in EC50 to LPV was 4.25 fold (95% CI, 1.39-7.11, p = 0.91). All viruses remained susceptible to DRV. In our assay system, the major PI resistance mutation I84V, which emerged in one individual, conferred a 10.5-fold reduction in LPV susceptibility. One of the six patients exhibited a significant reduction in susceptibility between pre-PI and failure timepoints (from 4.7 fold to 9.6 fold) in the absence of known major mutations in protease, but associated with changes in Gag: V7I, G49D, R69Q, A120D, Q127K, N375S and I462S. Phylogenetic analysis provided evidence of the emergence of genetically distinct viruses at the time of treatment failure, indicating ongoing viral evolution in Gag-protease under PI pressure. CONCLUSIONS: Here we observe in one patient the development of significantly reduced susceptibility conferred by changes in Gag which may have contributed to treatment failure on a protease inhibitor containing regimen. Further phenotype-genotype studies are required to elucidate genetic determinants of protease inhibitor failure in those who fail without traditional resistance mutations whilst PI use is being scaled up globally