1,171 research outputs found
Do plant species influence soil gas fluxes in tropical forests?
Abstract ID: 53. Publicado também on-line
Trace gas fluxes from intensively managed rice and soybean fields across three growing seasons in the brazilian amazon.
The emission of gases that may potentially intensify the greenhouse effect has received special attention due to their ability to raise global temperatures and possibly modify conditions for life on earth. The objectives of this study were the quantification of trace gas flux (N2O, CO2 and CH4) in soils of the lower Amazon basin that are planted with rice and soybean, and the relation of this flux to soil physical and chemical parameters and to precipitation. This study was conducted in agricultural fields planted with rice (Oryza Sativa) and soybean (Glycine max), located near the cities of Belterra and Santarém in western Pará State, Brazil, during the production years of 2005-2007. Measurements were done using static chambers in the field, and samples were analyzed by gas chromatography in the laboratory. Statistical analysis was conducted to determine variation ingas flux in the two crops, and the results show that CO2 flux varied between 305 and 227 mg-C m-2 h-1 under rice, and 243 and 156 mg-C m-2 h-1 under soybean. Flux of nitrous oxide (N2O) under rice varied between 4.5 and 20.4 ?g-N m-2 h-1, and under soybean flux variation was between 4.0 and 9.4 ?g- N m-2 h-1. Variation in flux of methane (CH4) under rice was between 5.1 and 14.0 ?g-C m-2 h-1, and under soybean it was 0.4 and 1.2 ?g-C m-2 h-1. These results demonstrate that, during our study period, the rice crop had higher flux for all trace gases than the soybean crop
The effectiveness of nitrofurantoin, fosfomycin and trimethoprim for the treatment of cystitis in relation to renal function
Objectives: We evaluated the effect of renal function on clinical failure rates of nitrofurantoin, fosfomycin and trimethoprim for the treatment of cystitis in primary care. Methods: Data were retrospectively obtained from 78 Dutch general practitioner (GP) practices between 2013 and 2019. Eligible episodes in patients (>11 years) were those requiring 5 days of nitrofurantoin (NF5), single-dose fosfomycin–trometamol (FT1), 3 days of trimethoprim (TMP3) for uncomplicated cystitis, or 7 days of nitrofurantoin (NF7) or trimethoprim (TMP7) for complicated cystitis. Clinical failure was defined as second antibiotic prescription for cystitis or pyelonephritis within 28 days post-prescription. Mixed effects regression analysis was used, with patient and GP practice as random effects and demography, comorbidity, and cystitis history as fixed effects. Results: Adjusted odds ratios (aORs) for clinical failure per 10mL/min decrease in estimated glomerular filtration rate (eGFR) were 1.05 (95% CI: 1.01–1.09) for NF5 (n = 24,591), 0.96 (95% CI: 0.92–1.01) for FT1 (n = 5359), 0.98 (95% CI: 0.89–1.08) for TMP3 (n = 1064), 1.05 (95% CI: 1.02–1.09) for NF7 (n = 10,628) and 1.02 (95% CI: 0.93–1.14) for TMP7 (n = 831). In uncomplicated cystitis and eGFR ≥60 mL/min, clinical failures occurred in 14.6% (1895/12 980) of NF5-treated, 20.7% (266/1283) of FT1-treated (aOR versus NF5 1.37, 95% CI 1.18–1.59) and 20.8% (66/318) of TMP3-treated patients (aOR 1.42, 95% CI 1.07–1.87 versus NF5). In uncomplicated cystitis and eGFR <60 mL/min, FT1 resulted in 16.0% (39/244) and NF5 in 23.3% clinical failures (110/472), aOR: 0.61, 95% CI: 0.39–0.95). Conclusions: In eGFR ≥60 mL/min treatment with fosfomycin or trimethoprim for uncomplicated cystitis was associated with more clinical failure than treatment with nitrofurantoin, while in eGFR <60 mL/min nitrofurantoin was associated with more clinical failure than fosfomycin–trometamol. Renal function, if known, should be considered in the clinical decision-making for cystitis treatment
Morphobathymetry and formation processes of sediment waves in the Gulf of Valencia continental slope (NW Mediterranean)
Versión del edito
Age Trajectories of the Structural Connectome in Child and Adolescent Offspring of Individuals With Bipolar Disorder or Schizophrenia
Background: Offspring of parents with severe mental illness (e.g., bipolar disorder or schizophrenia) are at elevated risk of developing psychiatric illness owing to both genetic predisposition and increased burden of environmental stress. Emerging evidence indicates a disruption of brain network connectivity in young offspring of patients with bipolar disorder and schizophrenia, but the age trajectories of these brain networks in this high-familial-risk population remain to be elucidated. Methods: A total of 271 T1-weighted and diffusion-weighted scans were obtained from 174 offspring of at least 1 parent diagnosed with bipolar disorder (n = 74) or schizophrenia (n = 51) and offspring of parents without severe mental illness (n = 49). The age range was 8 to 23 years; 97 offspring underwent 2 scans. Anatomical brain networks were reconstructed into structural connectivity matrices. Network analysis was performed to investigate anatomical brain connectivity. Results: Offspring of parents with schizophrenia had differential trajectories of connectivity strength and clustering compared with offspring of parents with bipolar disorder and parents without severe mental illness, of global efficiency compared with offspring of parents without severe mental illness, and of local connectivity compared with offspring of parents with bipolar disorder. Conclusions: The findings of this study suggest that familial high risk of schizophrenia is related to deviations in age trajectories of global structural connectome properties and local connectivity strength.</p
Age Trajectories of the Structural Connectome in Child and Adolescent Offspring of Individuals With Bipolar Disorder or Schizophrenia
Background: Offspring of parents with severe mental illness (e.g., bipolar disorder or schizophrenia) are at elevated risk of developing psychiatric illness owing to both genetic predisposition and increased burden of environmental stress. Emerging evidence indicates a disruption of brain network connectivity in young offspring of patients with bipolar disorder and schizophrenia, but the age trajectories of these brain networks in this high-familial-risk population remain to be elucidated. Methods: A total of 271 T1-weighted and diffusion-weighted scans were obtained from 174 offspring of at least 1 parent diagnosed with bipolar disorder (n = 74) or schizophrenia (n = 51) and offspring of parents without severe mental illness (n = 49). The age range was 8 to 23 years; 97 offspring underwent 2 scans. Anatomical brain networks were reconstructed into structural connectivity matrices. Network analysis was performed to investigate anatomical brain connectivity. Results: Offspring of parents with schizophrenia had differential trajectories of connectivity strength and clustering compared with offspring of parents with bipolar disorder and parents without severe mental illness, of global efficiency compared with offspring of parents without severe mental illness, and of local connectivity compared with offspring of parents with bipolar disorder. Conclusions: The findings of this study suggest that familial high risk of schizophrenia is related to deviations in age trajectories of global structural connectome properties and local connectivity strength.</p
Acoustic and optical variations during rapid downward motion episodes in the deep north-western Mediterranean Sea
An Acoustic Doppler Current Profiler (ADCP) was moored at the deep-sea site
of the ANTARES neutrino telescope near Toulon, France, thus providing a unique
opportunity to compare high-resolution acoustic and optical observations
between 70 and 170 m above the sea bed at 2475 m. The ADCP measured downward
vertical currents of magnitudes up to 0.03 m s-1 in late winter and early
spring 2006. In the same period, observations were made of enhanced levels of
acoustic reflection, interpreted as suspended particles including zooplankton,
by a factor of about 10 and of horizontal currents reaching 0.35 m s-1. These
observations coincided with high light levels detected by the telescope,
interpreted as increased bioluminescence. During winter 2006 deep dense-water
formation occurred in the Ligurian subbasin, thus providing a possible
explanation for these observations. However, the 10-20 days quasi-periodic
episodes of high levels of acoustic reflection, light and large vertical
currents continuing into the summer are not direct evidence of this process. It
is hypothesized that the main process allowing for suspended material to be
moved vertically later in the year is local advection, linked with topographic
boundary current instabilities along the rim of the 'Northern Current'.Comment: 30 pages, 7 figure
Ketamine-Induced Disruption of Verbal Self-Monitoring Linked to Superior Temporal Activation
Introduction: Misattribution of distorted self-generated speech in patients with schizophrenia has been associated with increased lateral temporal activation. As a pharmacological model of schizophrenia, we tested whether ketamine would induce the same effects in healthy individuals. Methods: Participants were 8 healthy male volunteers who were nave to ketamine (mean age: 28 years). Ketamine (0.23 mg/kg bolus followed by 0.64 mg/kg/h) and placebo infusions were administered in a double-blind, randomised order, during 2 functional magnetic resonance imaging (fMRI) sessions. Each fMRI session consisted of a verbal self-monitoring task in which auditory feedback was experimentally modified. Results: Ketamine was associated with psychotic and dissociative symptoms. Participants made more misattributions of distorted self-generated speech (p <0.02) during the ketamine infusion. Ketamine led to reduced activation in the left superior temporal cortex during self-distorted speech, regardless of whether the speech was identified correctly or not, as compared to the placebo infusion. Misidentification of speech that had been distorted was not associated with any increase in brain activation in during the placebo infusion, however ketamine-induced misattributions were associated with a relative increase in left superior temporal cortex activation. Discussion: These data are consistent with the notion that self-monitoring impairments underlie psychotic symptoms and suggest that N-methyl-D-aspartate (NMDA) receptor dysfunction may mediate self-monitoring deficits and psychotic phenomena in schizophrenia
Brain Plasticity and Intellectual Ability Are Influenced by Shared Genes
Although the adult brain is considered to be fully developed and stable until senescence when its size steadily decreases, such stability seems at odds with continued human (intellectual) development throughout life. Moreover, although variation in human brain size is highly heritable, we do not know the extent to which genes contribute to individual differences in brain plasticity. In this longitudinal magnetic resonance imaging study in twins, we report considerable thinning of the frontal cortex and thickening of the medial temporal cortex with increasing age and find this change to be heritable and partly related to cognitive ability. Specifically, adults with higher intelligence show attenuated cortical thinning and more pronounced cortical thickening over time than do subjects with average or below average IQ. Genes influencing variability in both intelligence and brain plasticity partly drive these associations. Thus, not only does the brain continue to change well into adulthood, these changes are functionally relevant because they are related to intelligence. Copyright©2010 the authors
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