982 research outputs found
Testing the use of sealable bags as an alternative and less expensive method for tracing isotopes in plant matter
The main purpose of the research was to find a less expensive method for sampling isotopes from plants. By collecting plant xylem in a plastic, sealable bag, filling the bag with dry air, letting it sit for 24 hours and then running it through the laser spectrometer, the isotopes of the plants will be traced; specifically, deuterium and oxygen-18. The bag method of this experiment comes from that of Hendry (2015) when he used it on soils. Once the raw data was collected it was transposed from vapor to liquid data. The values found match with previous isotopic collections that were done using IR mass spectrometry. This shows that this inexpensive method was comparable to previous methods and can allow for the study of isotopes to be more accessible to the scientific community
Detailed observations of the phytoplankton spring bloom in the stratifying central North Sea
Analysis of detailed time series of bio-optical and temperature data from the North Sea supports the view that a minimum level of turbulence is a prerequisite for the onset and maintenance of the phytoplankton spring bloom in shelf seas, which distinguishes these seas from the open ocean. The start of the spring bloom, primarily diatoms, is controlled by the light regime, while its progress is predominantly dependent upon episodic turbulence input following short periods of stratification, which allow the resuspension of a fast sinking (50-200 m day-1) phytoplankton community from the bottom mixing layer. A relationship between turbulence and the vertical distribution of phytoplankton is proposed which is found at synoptic time scales and on time scales of a day and less. Throughout the spring bloom, algal biomass is either equally distributed through the water column or concentrated in the bottom mixing layer. Growth can only be sustained in the near-surface layer during periods of substantial turbulence input. The establishment of semi-permanent seasonal stratification causes an almost complete reduction in near-surface biomass and a concomitant increase in biomass in the bottom mixing layer which subsequently acts as a source for occasional increased near-surface biomass until early summer
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
The distribution of deep-sea sponge aggregations (Porifera) in relation to oceanographic processes in the Faroe-Shetland Channel.
Deep-sea sponge aggregations have been identified as potential Vulnerable Marine Ecosystems under United Nations General Assembly Resolution 61/105. Understanding the distribution of these habitats is critical to future spatial management efforts, and central to this understanding are quantitative data on the environmental drivers of that distribution. Accumulations of large suspension feeders are hypothesised to aggregate in regions of internal wave formation. The causal link is thought to be an increase in the supply of food related to the incidence of internal waves, which results in resuspension of particulate organic matter on which the sponges feed. There is, however, almost no empirical evidence to support this hypothesis for deep-sea sponge aggregations, although there is strong circumstantial evidence. We tested the relationship between sponge density and 1) temperature range (as a measure of internal wave presence in this region), and 2) optical backscatter (a measure of particulate flux) for a known sponge aggregation in the Faroe-Shetland Channel where internal wave interaction with the slope is further well-documented. 25 benthic video transects, ranging from 422 to 979âŻm water depth were conducted in the study region. 225 images were analysed and all taxa identified to morphotypes and quantified. Temperature and optical backscatter data were drawn from archived CTD data, and data from long term (4 months) and 2 seasonal short term (11 days) mooring deployments from the region. A generalised linear model was used to test the relationship between sponge density and temperature range (ÎT), and sponge density and optical backscatter. The results showed a statistically significant positive relationship between sponge density and temperature range, with the highest sponge densities occurring at depths of greatest temperature range. They showed a statistically significant positive relationship between sponge density and optical backscatter for long term and one short term seasonal deployment (SepâOct), but a weak negative relationship for the other short term mooring deployment (April-May). We conclude that sponge aggregations in the Faroe-Shetland Channel are associated with slope regions that are subjected to abrupt and pronounced changes in temperature due to intensified internal wave activity over the slope between depths of 400â600 and that lead to intensified near-bed currents and elevated resuspension of particulate. Our data provide empirical evidence of the relationship between internal wave processes and deep-sea sponge aggregations. These data modify current theory on drivers of deep sea sponge aggregation distribution, suggesting aggregations also occur directly within regions of internal wave breaking, rather than simply proximal to these regions
Proefveld- en praktijkgegevens betreffende de aardappelteelt voor de zetmeelindustrie ten behoeve van modellering : groeicurves van zetmeelaardappelrassen op de noordelijke zand- en veenkoloniale gronden (1973-1999)
Gegevens over de groei van aardappelen op de noordelijke zand- en veenkoloniale gronden ten behoeve van de zetmeelindustrie zijn verzameld. Naast gegevens afkomstig van proefvelden zijn praktijkgegevens over de zetmeelaardappelteelt in Nederland bijeen gebracht en in een database ingevoerd. De proefboerderijen 'Geert Veenhuizenhoeve' te Borgercompagnie, 'A.G. Mulderhoeve' te EmmercompascuĂŒm en 'ât Kompas' te Valthermond liggen op veenkoloniale dalgrond, en de 'Kooijenburg' te Rolde op lemige zandgrond. De verzamelde gegevens hebben betrekking op de periode 1973-199
BCG as a case study for precision vaccine development: lessons from vaccine heterogeneity, trained immunity, and immune ontogeny
Vaccines have been traditionally developed with the presumption that they exert identical immunogenicity regardless of target population and that they provide protection solely against their target pathogen. However, it is increasingly appreciated that vaccines can have off-target effects and that vaccine immunogenicity can vary substantially with demographic factors such as age and sex. Bacille Calmette-GuĂ©rin (BCG), the live attenuated Mycobacterium bovis vaccine against tuberculosis (TB), represents a key example of these concepts. BCG vaccines are manufactured under different conditions across the globe generating divergent formulations. Epidemiologic studies have linked early life immunization with certain BCG formulations to an unanticipated reduction (âŒ50%) in all-cause mortality, especially in low birthweight males, greatly exceeding that attributable to TB prevention. This mortality benefit has been related to prevention of sepsis and respiratory infections suggesting that BCG induces âheterologousâ protection against unrelated pathogens. Proposed mechanisms for heterologous protection include vaccine-induced immunometabolic shifts, epigenetic reprogramming of innate cell populations, and modulation of hematopoietic stem cell progenitors resulting in altered responses to subsequent stimuli, a phenomenon termed âtrained immunity.â In addition to genetic differences, licensed BCG formulations differ markedly in content of viable mycobacteria key for innate immune activation, potentially contributing to differences in the ability of these diverse formulations to induce TB-specific and heterologous protection. BCG immunomodulatory properties have also sparked interest in its potential use to prevent or alleviate autoimmune and inflammatory diseases, including type 1 diabetes mellitus and multiple sclerosis. BCG can also serve as a model: nanoparticle vaccine formulations incorporating Toll-like receptor 8 agonists can mimic some of BCGâs innate immune activation, suggesting that aspects of BCGâs effects can be induced with non-replicating stimuli. Overall, BCG represents a paradigm for precision vaccinology, lessons from which will help inform next generation vaccines
An ovine model of hyperdynamic endotoxemia and vital organ metabolism
BACKGROUND: Animal models of endotoxemia are frequently used to understand the pathophysiology of sepsis and test new therapies. However, important differences exist between commonly used experimental models of endotoxemia and clinical sepsis. Animal models of endotoxemia frequently produce hypodynamic shock in contrast to clinical hyperdynamic shock. This difference may exaggerate the importance of hypoperfusion as a causative factor in organ dysfunction. This study sought to develop an ovine model of hyperdynamic endotoxemia and assess if there is evidence of impaired oxidative metabolism in the vital organs. METHODS: Eight sheep had microdialysis catheters implanted into the brain, heart, liver, kidney and arterial circulation. Shock was induced with a 4hr escalating dose infusion of endotoxin. After 3hrs vasopressor support was initiated with noradrenaline and vasopressin. Animals were monitored for 12hrs after endotoxemia. Blood samples were recovered for haemoglobin, white blood cell count, creatinine and proinflammatory cytokines (IL-1Beta, IL-6 & IL-8). RESULTS: The endotoxin infusion was successful in producing distributive shock with the mean arterial pressure decreasing from 84.5â±â12.8âmmHg to 49â±â8.03âmmHg (pâ<â0.001). Cardiac index remained within the normal range decreasing from 3.33â±â0.56âl/min/m to 2.89lâ±â0.36âl/min/m (pâ=â0.0845). Lactate/pyruvate ratios were not significantly abnormal in the heart, brain, kidney or arterial circulation. Liver microdialysis samples demonstrated persistently high lactate/pyruvate ratios (mean 37.9â±â3.3). CONCLUSIONS: An escalating dose endotoxin infusion was successful in producing hyperdynamic shock. There was evidence of impaired oxidative metabolism in the liver suggesting impaired splanchnic perfusion. This may be a modifiable factor in the progression to multiple organ dysfunction and death
Dynamic Interactive Social Cognition Training in Virtual Reality (DiSCoVR) for adults with Autism Spectrum Disorder:A feasibility study
Background: Social cognitive difficulties in Autism Spectrum Disorder (ASD) can affect the daily lives of people with ASD profoundly, impacting the development and maintenance of meaningful social relations. Social cognition training (SCT) is commonly used for improving social functioning, but lacks ecological validity and the ability to effectively mimic social situations. Development of virtual reality (VR) interventions, focusing on enhancing social cognition, could add to the effectiveness of SCT within ASD care, by offering a safe, interactive and practical training setting, where generalization of knowledge and skills to the real-world are promoted. In this paper, our primary aim is to evaluate the feasibility and acceptance by participants and therapists of the Dynamic Interactive Social Cognition Method: Training in Virtual Reality (DiSCoVR) protocol as developed for adults with schizophrenic spectrum disorder (SSD), adapted for ASD (DiSCoVR-A). 26 participants, aged 18-63, took part in a pilot study. 22 participants completed baseline and post-assessment, including primary outcome evaluation assessment through a semi-structured interview. Secondary measures focused on social cognition, emotion recognition, mental flexibility, social anxiety, empathy and social responsiveness and were assessed at baseline (T0), post-treatment (T1), and at follow-up (T2) sixteen weeks after completion of the intervention. Results: Our results show that the majority of participant and therapists found the VR intervention acceptable and feasible, as reported in evaluation questionnaires and interviews. Conclusion: These preliminary findings are promising; however, controlled research is needed to further investigate the effectiveness of VR within social cognition training for adults with ASD
Early weight measures and long-term neuropsychological outcome of critically ill neonates and infants:a secondary analysis of the PEPaNIC trial
Neonates and infants surviving critical illness show impaired growth during critical illness and are at risk for later neuropsychological impairments. Early identification of individuals most at risk is needed to provide tailored long-term follow-up and care. The research question is whether early growth during hospitalization is associated with growth and neuropsychological outcomes in neonates and infants after pediatric intensive care unit admission (PICU). This is a secondary analysis of the PEPaNIC trial. Weight measurements upon PICU admission, at PICU discharge, at hospital discharge, at 2- and 4-year follow-up, and of different subgroups were compared using (paired) t-tests. Multiple linear regression analyses were performed to investigate the association between early growth in weight measures and neuropsychological outcomes at 4-year follow-up. One hundred twenty-one infants were included, and median age upon admission was 21Â days. Growth in weight per week was less than the age-appropriate norm, resulting in a decrease in weight-for-age Z-score during hospitalization. Weight is normalized at 2- and 4-year follow-up. Weight gain in kilograms per week and change in weight Z-score were not associated with neurodevelopmental outcome measures at 4-year follow-up. Lower weight-for-age Z-score at PICU admission and at hospital discharge was associated only with lower weight and height Z-scores at 4-year follow-up. Conclusion: Growth in weight during hospital stay of young survivors of critical illness is impaired. Worse early growth in weight is associated with lower weight and height but not with neuropsychological outcomes at 4-year follow-up. What is Known: âą Critically ill neonates and infants show impaired early growth during admission and are at risk for later neuropsychological impairments. âą Unraveling the association between early growth and later neuropsychological impairments is crucial since the first year of life is critical for brain development. What is New: âą Critically ill neonates and infants had age appropriate weight measures at 4-year follow-up. âą Poor growth in weight during hospital stay was not associated with poorer cognitive, emotional, or behavioral functioning four years after critical illness.</p
Genetic contributions to human brain morphology and intelligence
Variation in gray matter (GM) and white matter (WM) volume of the adult human brain is primarily genetically determined. Moreover, total brain volume is positively correlated with general intelligence, and both share a common genetic origin. However, although genetic effects on morphology of specific GM areas in the brain have been studied, the heritability of focal WM is unknown. Similarly, it is unresolved whether there is a common genetic origin of focal GM and WM structures with intelligence. We explored the genetic influence on focal GM and WM densities in magnetic resonance brain images of 54 monozygotic and 58 dizygotic twin pairs and 34 of their siblings. For genetic analyses, we used structural equation modeling and voxel-based morphometry. To explore the common genetic origin of focal GM and WM areas with intelligence, we obtained cross-trait/cross-twin correlations in which the focal GM and WM densities of each twin are correlated with the psychometric intelligence quotient of his/her cotwin. Genes influenced individual differences in left and right superior occipitofrontal fascicle (heritability up to 0.79 and 0.77), corpus callosum (0.82, 0.80), optic radiation (0.69, 0.79), corticospinal tract (0.78, 0.79), medial frontal cortex (0.78, 0.83), superior frontal cortex (0.76, 0.80), superior temporal cortex (0.80, 0.77), left occipital cortex (0.85), left postcentral cortex (0.83), left posterior cingulate cortex (0.83), right parahippocampal cortex (0.69), and amygdala (0.80, 0.55). Intelligence shared a common genetic origin with superior occipitofrontal, callosal, and left optical radiation WM and frontal, occipital, and parahippocampal GM (phenotypic correlations up to 0.35). These findings point to a neural network that shares a common genetic origin with human intelligence
- âŠ