Sexual abuse and suicidality: gender differences in a large community sample of adolescents

Objective: A cross-sectional study of gender specific relationships between self-reported child sexual abuse and suicidality in a community sample of adolescents. Method: Students aged 14 years on average (N = 2,485) from 27 schools in South Australia completed a questionnaire including items on sexual abuse and suicidality, and measures of depression (Centre for Epidemiological Studies Depression Scale), hopelessness (Beck Hopelessness Scale), and family functioning (McMaster Family Assessment Device General Functioning Subscale). Data analysis included logistic regression. Results: In boys, self-report sexual abuse is strongly and independently associated with suicidal thoughts, plans, threats, deliberate self-injury, and suicide attempts, after controlling for current levels of depression, hopelessness, and family dysfunction. In girls, the relationship between sexual abuse and suicidality is mediated fully by depression, hopelessness, and family dysfunction. Girls who report current high distress about sexual abuse, however, have a threefold increased risk of suicidal thoughts and plans, compared to non-abused girls. Boys who report current high distress about sexual abuse have 10-fold increased risk for suicidal plans and threats, and 15-fold increased risk for suicide attempts, compared to non-abused boys. Fifty-five percent (n = 15) of sexually abused boys attempted suicide versus 29% (n = 17) girls. Conclusions: A history of sexual abuse should alert clinicians, professionals and caters in contact with adolescents, to greatly increased risks of suicidal behavior and attempts in boys, even in the absence of depression and hopelessness. Distress following sexual abuse, along with depression and hopelessness indicate increased risk of suicidal behavior in girls, as well as boys. (C) 2004 Published by Elsevier Ltd.

Symptoms and diagnosis of borderline, early and advanced epithelial ovarian cancer

Objective. To document symptoms associated with borderline, early and advanced ovarian cancer and identify personal characteristics associated with early versus late diagnosis. Methods. Information concerning symptoms and diagnosis history was available from 811 women with ovarian cancer who took part in an Australian case–control study in the early 1990s. Women were classified into three groups for comparison based on their diagnosis: borderline, early (stage I–II) and advanced (stage III–IV) invasive cancer. Results. Sixteen percent of women with borderline tumors, 7% with early cancer and 4% with advanced cancer experienced no symptoms before diagnosis (P < 0.0001). Among women with symptoms, abdominal pain (44%) or swelling (39%) were most frequently reported; an abdominal mass (12%) and gynecological symptoms (12%) were less common. Compared to advanced stage cancer, women with early stage cancer were more likely to report an abdominal mass or urinary symptoms but less likely to report gastrointestinal problems or general malaise. General malaise and ‘other’ symptoms were least common in borderline disease. Older women, and those with higher parity or a family history of breast or ovarian cancer, were more likely to be diagnosed at an advanced stage of disease. Conclusions. Women who experience persistent or recurrent abdominal symptoms, particularly swelling and/or pain should be encouraged to seek medical attention and physicians should be alert to the possibility of ovarian cancer even in the absence of an abdominal mass. Further information about the prevalence of these symptoms in the general population is essential to assist physicians in patient management.

The mental health country profile: Background, design and use of a systematic method of appraisal

This article describes the construction and use of a systematic structured method of mental health country situation appraisal, in order to help meet the need for conceptual tools to assist planners and policy makers develop and audit policy and implementation strategies. The tool encompasses the key domains of context, needs, resources, provisions and outcomes, and provides a framework for synthesizing key qualitative and quantitative information, flagging up gaps in knowledge, and for reviewing existing policies. It serves as an enabling tool to alert and inform policy makers, professionals and other key stakeholders about important issues which need to be considered in mental health policy development. It provides detailed country specific information in a systematic format, to facilitate global sharing of experiences of mental health reform and strategies between policy makers and other stakeholders. Lastly, it is designed to be a capacity building tool for local stakeholders to enhance situation appraisal, and multisectorial policy development and implementation.

Serious adverse events in the Australian National Evaluation of Pharmacotherapies for Opioid Dependence (NEPOD)

Aims The study estimated serious adverse event (SAE) rates among entrants to pharmacotherapies for opioid dependence, during treatment and after leaving treatment. Design A longitudinal study based on data from 12 trials included in the Australian National Evaluation of Pharmacotherapies for Opioid Dependence (NEPOD). Participants and settings A total of 1.244 heroin users and methadone patients treated in hospital, community and GP settings. Intervention Six trials included detoxification; all included treatment with methadone, buprenorphine, levo-alpha-acetyl-methadol (LAAM) or naltrexone. Findings During 394 person-years of observation, 79 SAEs of 28 types were recorded. Naltrexone participants experienced 39 overdoses per 100 person-years after leaving treatment (44% occurred within 2 weeks after stopping naltrexone). This was eight times the rate recorded among participants who left agonist treatment. Rates of all other SAEs were similar during treatment versus out of treatment, for both naltrexone-treated and agonist-treated participants. Five deaths occurred, all among participants who had left treatment, at a rate of six per 100 person-years. Total SAE rates during naltrexone and agonist treatments were similar (20, 14 per 100 person-years, respectively). Total SAE and death rates observed among participants who had left treatment were three and 19 times the corresponding rates during treatment. Conclusions Individuals who leave pharmacotherapies for opioid dependence experience higher overdose and death rates compared with those in treatment. This may be due partly to a participant self-selection effect rather than entirely to pharmacotherapy being protective. Clinicians should alert naltrexone treatment patients in particular about heroin overdose risks. Duty of care may extend beyond cessation of dosing.

Effect of gaze direction on neck muscle activity during cervical rotation

Control of the neck muscles is coordinated with the sensory organs of vision, hearing and balance. For instance, activity of splenius capitis (SC) is modified with gaze shift. This interaction between eye movement and neck muscle activity is likely to influence the control of neck movement. The aim of this study was to investigate the effect of eye position on neck muscle activity during cervical rotation. In eleven subjects we recorded electromyographic activity (EMG) of muscles that rotate the neck to the right [right obliquus capitis inferior (OI), multifides (MF), and SC, and left sternocleidomastoid (SCM)] with intramuscular or surface electrodes. In sitting, subjects rotated the neck in each direction to specific points in range that were held statically with gaze either fixed to a guide (at three different positions) that moved with the head to maintain a constant intra-orbit eye position or to a panel in front of the subject. Although right SC and left SCM EMG increased with rotation to the right, contrary to anatomical texts, OI EMG increased with both directions and MF EMG did not change from the activity recorded at rest. During neck rotation SCM and MF EMG was less when the eyes were maintained with a constant intra-orbit position that was opposite to the direction of rotation compared to trials in which the eyes were maintained in the same direction as the head movement. The inter-relationship between eye position and neck muscle activity may affect the control of neck posture and movement.

Effect of sequence variation in Plasmodium falciparum Histidine-Rich protein 2 on binding of specific monoclonal antibodies: Implications for rapid diagnostic tests for malaria

This Article Right arrow Full Text Right arrow Full Text (PDF) Right arrow Supplemental material Right arrow Alert me when this article is cited Right arrow Alert me if a correction is posted Services Right arrow Similar articles in this journal Right arrow Similar articles in PubMed Right arrow Alert me to new issues of the journal Right arrow Download to citation manager Right arrow Reprints and Permissions Right arrow Copyright Information Right arrow Books from ASM Press Right arrow MicrobeWorld Citing Articles Right arrow Citing Articles via HighWire Right arrow Citing Articles via Google Scholar Google Scholar Right arrow Articles by Lee, N. Right arrow Articles by McCarthy, J. Right arrow Search for Related Content PubMed Right arrow PubMed Citation Right arrow Articles by Lee, N. Right arrow Articles by McCarthy, J. Right arrow Pubmed/NCBI databases * Substance via MeSH Previous Article | Next Article Journal of Clinical Microbiology, August 2006, p. 2773-2778, Vol. 44, No. 8 0095-1137/06/$08.00+0 doi:10.1128/JCM.02557-05 Copyright © 2006, American Society for Microbiology. All Rights Reserved. Effect of Sequence Variation in Plasmodium falciparum Histidine- Rich Protein 2 on Binding of Specific Monoclonal Antibodies: Implications for Rapid Diagnostic Tests for Malaria{dagger} Nelson Lee,1,2 Joanne Baker,2 Kathy T. Andrews,1 Michelle L. Gatton,1,3 David Bell,4 Qin Cheng,2,3 and James McCarthy1* Australian Centre for International and Tropical Health and Nutrition, Queensland Institute of Medical Research and School of Population Health, University of Queensland, Queensland, Australia,1 Department of Drug Resistance and Diagnostics, Australian Army Malaria Institute, Brisbane, Australia,2 Malaria Drug Resistance and Chemotherapy, Queensland Institute of Medical Research, Queensland, Australia,3 World Health Organization, Regional Office for the Western Pacific, Manila, Philippines4 Received 8 December 2005/ Returned for modification 23 February 2006/ Accepted 26 May 2006 The ability to accurately diagnose malaria infections, particularly in settings where laboratory facilities are not well developed, is of key importance in the control of this disease. Rapid diagnostic tests (RDTs) offer great potential to address this need. Reports of significant variation in the field performance of RDTs based on the detection of Plasmodium falciparum histidine-rich protein 2 (HRP2) (PfHRP2) and of significant sequence polymorphism in PfHRP2 led us to evaluate the binding of four HRP2-specific monoclonal antibodies (MABs) to parasite proteins from geographically distinct P. falciparum isolates, define the epitopes recognized by these MABs, and relate the copy number of the epitopes to MAB reactivity. We observed a significant difference in the reactivity of the same MAB to different isolates and between different MABs tested with single isolates. When the target epitopes of three of the MABs were determined and mapped onto the peptide sequences of the field isolates, significant variability in the frequency of these epitopes was observed. These findings support the role of sequence variation as an explanation for variations in the performance of HRP2-based RDTs and point toward possible approaches to improve their diagnostic sensitivities

Phytotoxicity of surface waters of the Thames and Brisbane River Estuaries: A combined chemical analysis and bioassay approach for the comparison of two systems

The Thames Estuary, UK, and the Brisbane River, Australia, are comparable in size and catchment area. Both are representative of the large and growing number of the world's estuaries associated with major cities. Principle differences between the two systems relate to climate and human population pressures. In order to assess the potential phytotoxic impact of herbicide residues in the estuaries, surface waters were analysed with a PAM fluorometry-based bioassay that employs the photosynthetic efficiency (photosystem II quantum yield) of laboratory cultured microalgae, as an endpoint measure of phytotoxicity. In addition, surface waters were chemically analysed for a limited number of herbicides. Diuron atrazine and simazine were detected in both systems at comparable concentrations. In contrast, bioassay results revealed that whilst detected herbicides accounted for the observed phytotoxicity of Brisbane River extracts with great accuracy, they consistently explained only around 50% of the phytotoxicity induced by Thames Estuary extracts. Unaccounted for phytotoxicity in Thames surface waters is indicative of unidentified phytotoxins. The greatest phytotoxic response was measured at Charing Cross, Thames Estuary, and corresponded to a diuron equivalent concentration of 180 ng L-1. The study employs relative potencies (REP) of PSII impacting herbicides and demonstrates that chemical analysis alone is prone to omission of valuable information. Results of the study provide support for the incorporation of bioassays into routine monitoring programs where bioassay data may be used to predict and verify chemical contamination data, alert to unidentified compounds and provide the user with information regarding cumulative toxicity of complex mixtures. (c) 2005 Elsevier B.V. All rights reserved.

A GESTÃO DE RECURSOS HUMANOS: PERFIL ESTRATÉGICO OU OPERACIONAL?

Este trabalho tem como objetivo examinar o estágio atual do processo de desenvolvimento da função de Recursos Humanos (RH) e se esses papéis, ainda requeridos ou já existentes, atendem às expectativas dos diversos estratos envolvidos, auxiliando na busca de melhores resultados para as empresas e os que nelas trabalham. Nesse contexto, baseou-se na premissa de que as crescentes alterações sócio-culturais e o constante avanço tecnológico experimentado no mundo, além das modificações das condições de vida, permeiam e alteram as condições de trabalho e expectativas de convivência entre as pessoas e suas organizações, exigindo que a função Recursos Humanos busque alternativas de ação para alinhar suas estratégias às das organizações onde atua e fazendo com que o sistema de gestão de pessoas seja fonte de vantagem competitiva sustentável. Buscou-se analisar se o que uma organização faz e como o faz é fator que a distingue das demais, se sua especialização e habilidades deixam-na mais capaz, se é essa capacidade que a torna essencialmente mais competente e técnica e se, nesse quadro, o posicionamento postural de Recursos Humanos é adequado. Também procurou analisar a atuação de diversos públicos de interesse, como os envolvidos nas atividades trabalhistas-sindicais e se os novos elementos da governança corporativa são definidores de atuação estratégica para os profissionais da área estudada. Dentro dos conceitos acima, verificaram-se teorias e fatos, além de pesquisa, que resumissem e explicassem o que se sabe sobre o objeto estudado, classificando-os e sistematizando-os conforme apresentados na realidade empírica e selecionando aqueles a serem estudados, na tentativa de buscar e prever novas caracterizações dos papéis desempenhados por Recursos Humanos, que melhor os clarifiquem. A análise dos levantamentos teóricos realizados reforçou a importância das vantagens competitivas para o sucesso empresarial e a necessidade de que pessoas de conhecimento tornem-se mais produtivas na busca dessas vantagens, além de constatar que essas pessoas devem estar preparadas para atuar em contextos exigentes e complexos e o alerta de que a atuação estratégica de RH é fundamental na solidificação desse novo perfil dos empregados. As diversas funções operacionais atribuídas a Recursos Humanos, entre elas a administração da infra-estrutura e o gerenciamento da contribuição dos funcionários, devem complementar-se, agora, com as chamadas funções estratégicas, geradoras de valor, destacando-se o auxílio na definição das estratégias empresariais e sua tradução em ações de transformação e mudança. Mais do que isso se verificou a crescente preocupação de autores em aliar os recentes conceitos de governança corporativa a essa função estratégica de Recursos Humanos.(AU)

A COMUNICAÇÃO PODE SALVAR VIDAS: ALERTAS ANTECIPADOS DE EMERGÊNCIAS CLIMÁTICAS PELA TELEVISÃO DIGITAL INTERATIVA BRASILEIRA

Alertas Antecipados de Emergência são elementos importantes na redução de riscos de desastres, evitando a perda de vidas e reduzindo seu impacto econômico e material. Dentre os meios de comunicação mais eficazes para geração de alertas antecipados, a televisão digital com sua capacidade de emissão de um para muitos e ainda com suas possibilidades de gerar informações reativas com dados enviados pelo mesmo sinal de TV é, no momento, o estado da arte para ajudar a população em situações de risco, comprovado através de estudos comparativos entre os sistemas de alerta de emergência existentes hoje em todo o mundo. Neste trabalho são comparados os sistemas japonês e norte-americano, sendo que os referenciais teóricos apresentados focalizam o processo comunicacional de uma informação de emergência, a partir de diversas teorias que fundamentam o processo de comunicação em situações de crise, com os quais chegou-se à conclusão de que a tecnologia de televisão Digital Brasileira, juntamente com a infraestrutura essencial para detecção de riscos e confiabilidade para a geração de alertas antecipados já existente, dispõe de todo o ferramental necessário para a criação de um sistema nacional. Por fim são apresentadas as indicações iniciais para a criação de um modelo para uma comunicação eficaz e efetiva de informações de emergência destinado à população brasileira.

AVALIAÇÃO DAS TÁBUAS ÓSSEAS VESTIBULARES E LINGUAIS DOS DENTES ANTERIORES INFERIORES E MOLARES SUPERIORES APÓS O TRATAMENTO COM OS APARELHOS FUNCIONAIS FIXOS FORSUS E TWIN FORCE BITE CORRECTOR

Pelo fato das consequências do uso de aparelhos ortopédicos fixos sobre o periodonto ósseo vestibular e lingual ainda serem uma incógnita para o ortodontista clínico e pesquisador, este estudo teve como objetivo avaliar, por meio de tomografia computadorizada de feixe cônico (TCFC) as alterações em espessura das tábuas ósseas vestibulares e linguais em primeiros molares superiores e incisivos e caninos inferiores, após a utilização de aparelhagem fixa e dos aparelhos Twin Force (grupo A) e Forsus (grupo B) para o tratamento da maloclusão de Classe II, 1ª divisão. Para tanto, obteve-se uma amostra de 22 pacientes jovens adultos, divididos em dois grupos, de acordo com o aparelho propulsor da mandíbula. Grupo experimental A: 11 pacientes, 6 masculinos e 5 femininos, com idade média de 15,09 anos na instalação do Twin Force, e 11 pacientes, 7 masculinos e 4 femininos, com idade média de 15,45 anos na instalação do Forsus. O tempo médio de uso do aparelho Twin Force foi de 3,73 meses e do Forsus, 7,09 meses. O grupo A realizou TCFC antes do início do tratamento (T1), antes da instalação do Twin Force (T2), após a remoção do Twin Force (T3); e o grupo B somente antes da instalação do Forsus (T2) e após a remoção do Forsus (T3). Para comparação entre os tempos T2 e T3 foi utilizado o teste t pareado e entre os tempos T1, T2 e T3 foi utilizada a Análise de Variância (ANOVA) a um critério e o teste post-hoc de Tukey. Para comparação entre os grupos foi utilizado o teste t . Na comparação intergrupos os resultados evidenciaram que não houve diferença estatisticamente significante entre as alterações das espessuras das tábuas ósseas vestibular e lingual; por outro lado, na avaliação intra-grupo, de 48 medidas avaliadas, no grupo A houve reduções estatisticamente significantes nos terços cervical e médio por vestibular, nos dentes anteroinferiores e nos primeiros molares superiores e aumento nos terços cervical e médio, por lingual nos dentes anteriores inferiores, totalizando 25 medidas significantes. Já no grupo B, houve aumento significante da tábua óssea lingual nos dentes anteriores inferiores e redução em vestibular nos molares superiores, totalizando apenas sete medidas significantes, mas com mais medidas significantes de redução óssea vestibular em terços cervical e médio nos primeiros molares superiores, em comparação com o grupo A. Não houve diferença significante entre as medições obtidas com voxel 0,2 mm e 0,4 mm e nem dimorfismo entre os gêneros. As reduções em espessura óssea alveolar, principalmente em terços cervicais e médios vestibulares nos dentes avaliados neste estudo são um alerta ao clínico, para que realize essa abordagem diagnóstica periodontal antes de iniciar o tratamento ortodôntico.

INTERVENÇÃO LÚDICO-SIMBÓLICA JUNTO A PORTADORES DE DISPEPSIA FUNCIONAL

O presente estudo aborda uma intervenção grupal lúdico-simbólica junto a portadores de dispepsia funcional (DF), um distúrbio gastrointestinal caracterizado por sintomas como dor ou desconforto na região superior do abdômen, sem causa orgânica. Tem como objetivo intervir de forma grupal lúdicosimbólica junto ao portador de DF; analisar o nível de estresse dessa população e relacionar os dados da intervenção frente o nível de estresse. Trata-se de pesquisa exploratório-descritiva de caráter qualitativo. A intervenção grupal utiliza-se de técnicas de imaginação e pensamento dirigido; o nível de stress é avaliado através do Inventário de Sintomas de Stress para adultos de LIPP (ISSL). Os participantes do grupo são 12, predominantemente do sexo feminino, sendo a metade entre 20 e 50 anos e os demais, acima. Através da análise de conteúdo dos dados da entrevista dirigida pôde-se observar que todos fizeram uma associação do aparecimento dos sintomas a conflitos emocionais, focalizando cenas e situações como fatores estressores e desencadeadores da dispepsia funcional. A análise simbólica das intervenções grupais tem como base teórica a psicologia analítica de Carl Gustav Jung. Os resultados demonstraram que os participantes da intervenção grupal apresentaram redução dos sintomas da dispepsia funcional e do nível de estresse, sendo que, no início oito participantes encontravam-se na fase de resistência; um na de alerta e três sem estresse e, ao final, três se encontram na fase de resistência, um permanece na fase alerta e oito sem estresse. Essa transformação ocorreu após terem considerado os sintomas como símbolos de emoções e sentimentos através das intervenções lúdico-simbólicas, e após tê-los integrados à consciência ao fazerem conexões psíquicas entre mente e corpo para reconhecerem atitudes tomadas ou a tomar e agilizar enfrentamentos para não cristalizar sintomas da dispepsia funcional, do ponto de vista da psicologia analítica.

O EFEITO DO CONTROLE RESPIRATÓRIO EM VARIÁVEIS ELETROFISIOLÓGICAS DA ATENÇÃO

A prática do ioga tem se tornado cada vez mais popular, não apenas pelos benefícios físicos, mas principalmente pelo bem-estar psicológico trazido pela sua prática. Um dos componentes do ioga é o Prãnãyama, ou controle da respiração. A atenção e a respiração são dois mecanismos fisiológicos e involuntários requeridos para a execução do Prãnãyama. O principal objetivo desse estudo foi verificar se variáveis contínuas do EEG (potência de diferentes faixas que o compõem) seriam moduladas pelo controle respiratório, comparando-se separadamente as duas fases do ciclo respiratório (inspiração e expiração), na situação de respiração espontânea e controlada. Fizeram parte do estudo 19 sujeitos (7 homens/12 mulheres, idade média de 36,89 e DP = ± 14,46) que foram convidados a participar da pesquisa nas dependências da Faculdade de Saúde da Universidade Metodista de São Paulo. Para o registro do eletroencefalograma foi utilizado um sistema de posicionamento de cinco eletrodos Ag AgCl (FPz, Fz, Cz, Pz e Oz) fixados a uma touca de posicionamento rápido (Quick-Cap, Neuromedical Supplies®), em sistema 10-20. Foram obtidos valores de máxima amplitude de potência (espectro de potência no domínio da frequência) nas frequências teta, alfa e beta e delta e calculada a razão teta/beta nas diferentes fases do ciclo respiratório (inspiração e expiração), separadamente, nas condições de respiração espontânea e de controle respiratório. Para o registro do ciclo respiratório, foi utilizada uma cinta de esforço respiratório M01 (Pletismógrafo). Os resultados mostram diferenças significativas entre as condições de respiração espontânea e de controle com valores das médias da razão teta/beta menores na respiração controlada do que na respiração espontânea e valores de média da potência alfa sempre maiores no controle respiratório. Diferenças significativas foram encontradas na comparação entre inspiração e expiração da respiração controlada com diminuição dos valores das médias da razão teta/beta na inspiração e aumento nos valores das médias da potência alfa, sobretudo na expiração. Os achados deste estudo trazem evidências de que o controle respiratório modula variáveis eletrofisiológicas relativas à atenção refletindo um estado de alerta, porém mais relaxado do que na situação de respiração espontânea.

Why are health care interventions delivered over the internet? A systematic review of the published literature

Background: As Internet use grows, health interventions are increasingly being delivered online. Pioneering researchers are using the networking potential of the Internet, and several of them have evaluated these interventions. Objective: The objective was to review the reasons why health interventions have been delivered on the Internet and to reflect on the work of the pioneers in this field in order to inform future research. Methods: We conducted a qualitative systematic review of peer-reviewed evaluations of health interventions delivered to a known client/patient group using networked features of the Internet. Papers were reviewed for the reasons given for using the Internet, and these reasons were categorized. Results: We included studies evaluating 28 interventions plus 9 interventions that were evaluated in pilot studies. The interventions were aimed at a range of health conditions. Reasons for Internet delivery included low cost and resource implications due to the nature of the technology; reducing cost and increasing convenience for users; reduction of health service costs; overcoming isolation of users; the need for timely information; stigma reduction; and increased user and supplier control of the intervention. A small number of studies gave the existence of Internet interventions as the only reason for undertaking an evaluation of this mode of delivery. Conclusions: One must remain alert for the unintended effects of Internet delivery of health interventions due to the potential for reinforcing the problems that the intervention was designed to help. Internet delivery overcomes isolation of time, mobility, and geography, but it may not be a substitute for face-to-face contact. Future evaluations need to incorporate the evaluation of cost, not only to the health service but also to users and their social networks. When researchers report the outcomes of Internet-delivered health care interventions, it is important that they clearly state why they chose to use the Internet, preferably backing up their decision with theoretical models and exploratory work. Evaluation of the effectiveness of a health care intervention delivered by the Internet needs to include comparison with more traditional modes of delivery to answer the following question: What are the added benefits or disadvantages of Internet use that are particular to this mode of delivery? © Griffiths, Frances, Lindenmeyer, Antje, Powell, John, Thorogood, Margaret.

Neuromagnetic investigations of functional organisation within human visual cortex

This thesis describes a series of experimental investigations into the functional organisation of human visual cortex using neuromagnetometry.This technique combines good spatial and temporal resolution enabling identification of the location and temporal response characteristics of cortical neurones within alert humans. To activate different neuronal populations and cortical areas a range of stimuli were used, the parameters of which were selected to match the known physiological properties of primate cortical neurones. In one series of experiments the evoked magnetic response was recorded to isoluminant red/green gratings. Co-registration of signal and magnetic resonance image data indicated a contribution to the response from visual areas V1, V2 and V4. To investigate the spatio-temporal characteristics of neurones within area V1 the evoked response was recorded for a range of stimulus spatial and temporal frequencies. The response to isoluminant red/green gratings was dominated by a major component which was found to have bandpass spatial frequency tuning with a peak at 1-2 cycles/degree, falling to the level of the noise at 6-8 cycles/degree. The temporal frequency tuning characteristics of the response showed bimodal sensitivity with peaks at 0-1Hz and 4Hz. In a further series of experiments the luminance evoked response was recorded to red/black, yellow/black and achromatic gratings and in all cases was found to be more complex than the isoluminant chromatic response, comprising up to three distinct components. The major response peak showed bandpass spatial frequency tuning characteristics, peaking at 6-8 cycles/degree, falling to the level of the noise at 12-16 cycles/degree. The results provide evidence to suggest that within area V1 the same neuronal population encodes both chromatic and luminance information and has spatial frequency tuning properties consistent with single-opponent cells. Furthermore, the results indicate that cells within area V1 encode chromatic motion information over a wide range of temporal frequencies with temporal response characteristics suggestive of the existence of a sub-population of cells sensitive to high temporal frequencies.

Statnote 32 : the partial correlation coefficient

In previous statnotes, the application of correlation and regression methods to the analysis of two variables (X,Y) was described. The most important statistic used to measure the degree of correlation between two variables is Pearson’s ‘product moment correlation coefficient’ (‘r’). The correlation between two variables may be due to their common relation to other variables. Hence, investigators using correlation studies need to be alert to the possibilities of spurious correlation and the methods of ‘partial correlation’ are one method of taking this into account. This statnote applies the methods of partial correlation to three scenarios. First, to a fairly obvious example of a spurious correlation resulting from the ‘size effect’ involving the relationship between the number of general practitioners (GP) and the number of deaths of patients in a town. Second, to the relationship between the abundance of the nitrogen-fixing bacterium Azotobacter in soil and three soil variables, and finally, to a more complex scenario, first introduced in Statnote 24involving the relationship between the growth of lichens in the field and climate.