36 research outputs found

    Herbivory and eutrophication mediate grassland plant nutrient responses across a global climatic gradient

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    Plant stoichiometry, the relative concentration of elements, is a key regulator of ecosystem functioning and is also being altered by human activities. In this paper we sought to understand the global drivers of plant stoichiometry and compare the relative contribution of climatic vs. anthropogenic effects. We addressed this goal by measuring plant elemental (C, N, P and K) responses to eutrophication and vertebrate herbivore exclusion at eighteen sites on six continents. Across sites, climate and atmospheric N deposition emerged as strong predictors of plot‐level tissue nutrients, mediated by biomass and plant chemistry. Within sites, fertilization increased total plant nutrient pools, but results were contingent on soil fertility and the proportion of grass biomass relative to other functional types. Total plant nutrient pools diverged strongly in response to herbivore exclusion when fertilized; responses were largest in ungrazed plots at low rainfall, whereas herbivore grazing dampened the plant community nutrient responses to fertilization. Our study highlights (1) the importance of climate in determining plant nutrient concentrations mediated through effects on plant biomass, (2) that eutrophication affects grassland nutrient pools via both soil and atmospheric pathways and (3) that interactions among soils, herbivores and eutrophication drive plant nutrient responses at small scales, especially at water‐limited sites

    Methylphenidate and the risk of psychotic disorders and hallucinations in children and adolescents in a large health system

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    Previous studies have suggested that risk of psychotic events may be increased in children exposed to methylphenidate (MPH). However, this risk has not been fully examined and the possibility of confounding factors has not been excluded. Patients aged 6-19 years who received at least one MPH prescription were identified using Hong Kong population-based electronic medical records on the Clinical Data Analysis & Reporting System (2001-2014). Using the self-controlled case series design, relative incidence of psychotic events was calculated comparing periods when patients were exposed to MPH with non-exposed periods. Of 20 586 patients prescribed MPH, 103 had an incident psychotic event; 72 (69.9%) were male and 31 (30.1%) female. The mean age at commencement of observation was 6.95 years and the mean follow-up per participant was 10.16 years. On average, each participant was exposed to MPH for 2.17 years. The overall incidence of psychotic events during the MPH exposure period was 6.14 per 10 000 patient-years. No increased risk was found during MPH exposed compared to non-exposed periods (incidence rate ratio (IRR) 1.02 (0.53-1.97)). However, an increased risk was found during the pre-exposure period (IRR 4.64 (2.17-9.92)). Results were consistent across all sensitivity analyses. This study does not support the hypothesis that MPH increases risk of incident psychotic events. It does indicate an increased risk of psychotic events prior to the first prescription of MPH, which may be due to an association between psychotic events and the behavioural and attentional symptoms that led to psychiatric assessment and initiation of MPH treatment

    Cross-Modal Object Recognition Is Viewpoint-Independent

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    BACKGROUND: Previous research suggests that visual and haptic object recognition are viewpoint-dependent both within- and cross-modally. However, this conclusion may not be generally valid as it was reached using objects oriented along their extended y-axis, resulting in differential surface processing in vision and touch. In the present study, we removed this differential by presenting objects along the z-axis, thus making all object surfaces more equally available to vision and touch. METHODOLOGY/PRINCIPAL FINDINGS: Participants studied previously unfamiliar objects, in groups of four, using either vision or touch. Subsequently, they performed a four-alternative forced-choice object identification task with the studied objects presented in both unrotated and rotated (180 degrees about the x-, y-, and z-axes) orientations. Rotation impaired within-modal recognition accuracy in both vision and touch, but not cross-modal recognition accuracy. Within-modally, visual recognition accuracy was reduced by rotation about the x- and y-axes more than the z-axis, whilst haptic recognition was equally affected by rotation about all three axes. Cross-modal (but not within-modal) accuracy correlated with spatial (but not object) imagery scores. CONCLUSIONS/SIGNIFICANCE: The viewpoint-independence of cross-modal object identification points to its mediation by a high-level abstract representation. The correlation between spatial imagery scores and cross-modal performance suggest that construction of this high-level representation is linked to the ability to perform spatial transformations. Within-modal viewpoint-dependence appears to have a different basis in vision than in touch, possibly due to surface occlusion being important in vision but not touch

    European consensus statement on diagnosis and treatment of adult ADHD: The European Network Adult ADHD.

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    BACKGROUND: Attention deficit hyperactivity disorder (ADHD) is among the most common psychiatric disorders of childhood that persists into adulthood in the majority of cases. The evidence on persistence poses several difficulties for adult psychiatry considering the lack of expertise for diagnostic assessment, limited treatment options and patient facilities across Europe. METHODS: The European Network Adult ADHD, founded in 2003, aims to increase awareness of this disorder and improve knowledge and patient care for adults with ADHD across Europe. This Consensus Statement is one of the actions taken by the European Network Adult ADHD in order to support the clinician with research evidence and clinical experience from 18 European countries in which ADHD in adults is recognised and treated. RESULTS: Besides information on the genetics and neurobiology of ADHD, three major questions are addressed in this statement: (1) What is the clinical picture of ADHD in adults? (2) How can ADHD in adults be properly diagnosed? (3) How should ADHD in adults be effectively treated? CONCLUSIONS: ADHD often presents as an impairing lifelong condition in adults, yet it is currently underdiagnosed and treated in many European countries, leading to ineffective treatment and higher costs of illness. Expertise in diagnostic assessment and treatment of ADHD in adults must increase in psychiatry. Instruments for screening and diagnosis of ADHD in adults are available and appropriate treatments exist, although more research is needed in this age group

    Programmed DNA elimination of germline development genes in songbirds

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    In some eukaryotes, germline and somatic genomes differ dramatically in their composition. Here we characterise a major germline–soma dissimilarity caused by a germline-restricted chromosome (GRC) in songbirds. We show that the zebra finch GRC contains >115 genes paralogous to single-copy genes on 18 autosomes and the Z chromosome, and is enriched in genes involved in female gonad development. Many genes are likely functional, evidenced by expression in testes and ovaries at the RNA and protein level. Using comparative genomics, we show that genes have been added to the GRC over millions of years of evolution, with embryonic development genes bicc1 and trim71 dating to the ancestor of songbirds and dozens of other genes added very recently. The somatic elimination of this evolutionarily dynamic chromosome in songbirds implies a unique mechanism to minimise genetic conflict between germline and soma, relevant to antagonistic pleiotropy, an evolutionary process underlying ageing and sexual traits

    Neurodevelopmental Disruption of Cortico-Striatal Function Caused by Degeneration of Habenula Neurons

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    The habenula plays an important role on cognitive and affective functions by regulating monoamines transmission such as the dopamine and serotonin, such that its dysfunction is thought to underlie a number of psychiatric conditions. Given that the monoamine systems are highly vulnerable to neurodevelopmental insults, damages in the habenula during early neurodevelopment may cause devastating effects on the wide-spread brain areas targeted by monoamine innervations.Using a battery of behavioral, anatomical, and biochemical assays, we examined the impacts of neonatal damage in the habenula on neurodevelopmental sequelae of the prefrontal cortex (PFC) and nucleus accumbens (NAcc) and associated behavioral deficits in rodents. Neonatal lesion of the medial and lateral habenula by ibotenic acid produced an assortment of behavioral manifestations consisting of hyper-locomotion, impulsivity, and attention deficit, with hyper-locomotion and impulsivity being observed only in the juvenile period, whereas attention deficit was sustained up until adulthood. Moreover, these behavioral alterations were also improved by amphetamine. Our study further revealed that impulsivity and attention deficit were associated with disruption of PFC volume and dopamine (DA) receptor expression, respectively. In contrast, hyper-locomotion was associated with decreased DA transporter expression in the NAcc. We also found that neonatal administration of nicotine into the habenula of neonatal brains produced selective lesion of the medial habenula. Behavioral deficits with neonatal nicotine administration were similar to those caused by ibotenic acid lesion of both medial and lateral habenula during the juvenile period, whereas they were different in adulthood.Because of similarity between behavioral and brain alterations caused by neonatal insults in the habenula and the symptoms and suggested neuropathology in attention deficit/hyperactivity disorder (ADHD), these results suggest that neurodevelopmental deficits in the habenula and the consequent cortico-striatal dysfunctions may be involved in the pathogenesis and pathophysiology of ADHD

    Estimating the number of children exposed to parental psychiatric disorders through a national health survey

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    <p>Abstract</p> <p>Objective</p> <p>Children whose parents have psychiatric disorders experience an increased risk of developing psychiatric disorders, and have higher rates of developmental problems and mortality. Assessing the size of this population is important for planning of preventive strategies which target these children.</p> <p>Methods</p> <p>National survey data (CCHS 1.2) was used to estimate the number of children exposed to parental psychiatric disorders. Disorders were diagnosed using the World Psychiatric Health Composite International Diagnostic Interview (WMH-CIDI) (12 month prevalence). Data on the number of children below 12 years of age in the home, and the relationship of the respondents with the children, was used to estimate exposure. Parent-child relations were identified, as was single parenthood. Using a design-based analysis, the number of children exposed to parental psychiatric disorders was calculated.</p> <p>Results</p> <p>Almost 570,000 children under 12 live in households where the survey respondent met criteria for one or more mood, anxiety or substance use disorders in the previous 12 months, corresponding to 12.1% of Canadian children under the age of 12. Almost 3/4 of these children have parents that report receiving no mental health care in the 12 months preceding the survey. For 17% of all Canadian children under age 12, the individual experiencing a psychiatric disorder is the only parent in the household.</p> <p>Conclusion</p> <p>The high number of children exposed causes major concern and has important implications. Although these children will not necessarily experience adversities, they possess an elevated risk of accidents, mortality, and of developing psychiatric disorders. We expect these estimates will promote further research and stimulate discussion at both health policy and planning tables.</p

    Biochar: pyrogenic carbon for agricultural use: a critical review.

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    O biocarvĂŁo (biomassa carbonizada para uso agrĂ­cola) tem sido usado como condicionador do solo em todo o mundo, e essa tecnologia Ă© de especial interesse para o Brasil, uma vez que tanto a ?inspiração?, que veio das Terras Pretas de Índios da AmazĂŽnia, como o fato de o Brasil ser o maior produtor mundial de carvĂŁo vegetal, com a geração de importante quantidade de resĂ­duos na forma de finos de carvĂŁo e diversas biomassas residuais, principalmente da agroindĂșstria, como bagaço de cana, resĂ­duos das indĂșstrias de madeira, papel e celulose, biocombustĂ­veis, lodo de esgoto etc. Na Ășltima dĂ©cada, diversos estudos com biocarvĂŁo tĂȘm sido realizados e atualmente uma vasta literatura e excelentes revisĂ”es estĂŁo disponĂ­veis. Objetivou-se aqui nĂŁo fazer uma revisĂŁo bibliogrĂĄfica exaustiva, mas sim uma revisĂŁo crĂ­tica para apontar alguns destaques na pesquisa sobre biochar. Para isso, foram selecionados alguns temaschave considerados crĂ­ticos e relevantes e fez-se um ?condensado? da literatura pertinente, mais para orientar as pesquisas e tendĂȘncias do que um mero olhar para o passad
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