Biomass equations for forest regrowth in the eastern Amazon using randomized branch sampling.

Florestas secundárias ocupam uma área extensa e crescente na bacia Amazônica, porém determinações acuradas do impacto dessas florestas nos ciclos de carbono e nutrientes têm sido dificultadas pelo número reduzido de equações alométricas. Neste estudo, nós desenvolvemos equações em nível de comunidade e espécies individuais para estimar a biomassa total da parte aérea de uma floresta secundária com 15 anos de idade na Amazônia oriental. O trabalho de campo utilizou amostragem aleatória de ramos, que é uma técnica rápida, porém pouco utilizada em florestas tropicais. Baseada no erro padrão da série de segmentos individuais (14%), a consistência da série de segmentos totais amostrados foi considerada elevada, sugerindo que o método pode ser eficiente em comparação com procedimentos tradicionais. Os melhores ajustes foram obtidos com a equação tradicional Y=a×DBHb, onde Y é a biomassa, DBH é o diâmetro à altura do peito, e a e b são parâmetros para cada espécie arbórea. Ajustes razoáveis também foram alcançados com equações da forma Y=a(BA×H), onde Y é a biomassa, BA é a área basal, H é a altura e a é um parâmetro específico para cada espécie arbórea. Comparações com equações disponíveis na literatura indicaram uma faixa de erro provável de -33% a +29% usando-se relações desenvolvidas para outros sítios. Nós também apresentamos equações para os seguintes componentes da biomassa da parte aérea: tronco, ramos e folhas

Correlation but no causation between leaf nitrogen and maximum assimilation: the role of drought and reproduction in gas exchange in an understory tropical plant Miconia ciliata (Melastomataceae).

Alternative hypotheses were tested to explain a previously reported anomaly in the response of leaf photosynthetic capacity at light saturation (A..) in Miconia ciliata to dry-season irrigation. The anomaly is characterized by an abrupt increase in leaf A._ for nonirrigated plants at the onset of the rainy season to values that significantly exceeded corresponding measurements for plants that were irrigated during the previous dry season. Hypothesis I posits that a pulse in leaf nitrogen increases CO2 assimilation in nonirrigated plants at the onset of the wet season and is dampened for irrigated plants; this hypothesis was rejected because, although a wet-season nitrogen pulse did occur, it was identical for both irrigated and nonirrigated plants and was preceded by the increase in assimilation by nonirrigated plants. Hypothesis 2 posits that a reproduction-related, compensatory photosynthetic response occurs in nonirrigated plants following the onset of the wet season and is dampened in irrigated plants; consistent with hypothesis 2, high maximum assimilation rates for control plants in the wet season were significantly correlated with fruiting and flowering, whereas irrigation caused flowering and fruiting in the dry season, spreading M. ciliata reproductive activity in irrigated plants across the entire year

Long-term manipulation of soil moisture availability alters ecosystem processes in eastern Amazonian forest regrowth, Brazil.

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Problem gambling: a suitable case for social work?

Problem gambling attracts little attention from health and social care agencies in the UK. Prevalence surveys suggest that 0.6% of the population are problem gamblers and it is suggested that for each of these individuals, 10–17 other people, including children and other family members, are affected. Problem gambling is linked to many individual and social problems including: depression, suicide, significant debt, bankruptcy, family conflict, domestic violence, neglect and maltreatment of children and offending. This makes the issue central to social work territory. Yet, the training of social workers in the UK has consistently neglected issues of addictive behaviour. Whilst some attention has been paid in recent years to substance abuse issues, there has remained a silence in relation to gambling problems. Social workers provide more help for problems relating to addictions than other helping professions. There is good evidence that treatment, and early intervention for gambling problems, including psycho-social and public health approaches, can be very effective. This paper argues that problem gambling should be moved onto the radar of the social work profession, via inclusion on qualifying and post-qualifying training programmes and via research and dissemination of good practice via institutions such as the Social Care Institute for Excellence (SCIE). Keywords: problem gambling; addictive behaviour; socia

Completeness and Changes in Registered Data and Reporting Bias of Randomized Controlled Trials in ICMJE Journals after Trial Registration Policy

We assessed the adequacy of randomized controlled trial (RCT) registration, changes to registration data and reporting completeness for articles in ICMJE journals during 2.5 years after registration requirement policy.For a set of 149 reports of 152 RCTs with ClinicalTrials.gov registration number, published from September 2005 to April 2008, we evaluated the completeness of 9 items from WHO 20-item Minimum Data Set relevant for assessing trial quality. We also assessed changes to the registration elements at the Archive site of ClinicalTrials.gov and compared published and registry data.RCTs were mostly registered before 13 September 2005 deadline (n = 101, 66.4%); 118 (77.6%) started recruitment before and 31 (20.4%) after registration. At the time of registration, 152 RCTs had a total of 224 missing registry fields, most commonly 'Key secondary outcomes' (44.1% RCTs) and 'Primary outcome' (38.8%). More RCTs with post-registration recruitment had missing Minimum Data Set items than RCTs with pre-registration recruitment: 57/118 (48.3%) vs. 24/31 (77.4%) (χ(2) (1) = 7.255, P = 0.007). Major changes in the data entries were found for 31 (25.2%) RCTs. The number of RCTs with differences between registered and published data ranged from 21 (13.8%) for Study type to 118 (77.6%) for Target sample size.ICMJE journals published RCTs with proper registration but the registration data were often not adequate, underwent substantial changes in the registry over time and differed in registered and published data. Editors need to establish quality control procedures in the journals so that they continue to contribute to the increased transparency of clinical trials

Are citations from clinical trials evidence of higher impact research? An analysis of ClinicalTrials.gov

An important way in which medical research can translate into improved health outcomes is by motivating or influencing clinical trials that eventually lead to changes in clinical practice. Citations from clinical trials records to academic research may therefore serve as an early warning of the likely future influence of the cited articles. This paper partially assesses this hypothesis by testing whether prior articles referenced in ClinicalTrials.gov records are more highly cited than average for the publishing journal. The results from four high profile general medical journals support the hypothesis, although there may not be a cause-and effect relationship. Nevertheless, it is reasonable for researchers to use citations to their work from clinical trials records as partial evidence of the possible long-term impact of their research

Trial Publication after Registration in ClinicalTrials.Gov: A Cross-Sectional Analysis

Joseph Ross and colleagues examine publication rates of clinical trials and find low rates of publication even following registration in Clinicaltrials.gov