599 research outputs found
Identifying the magnetotail lobes with Cluster magnetometer data
We describe a novel method for identifying times when a spacecraft is in Earthâs magnetotail lobes solely using magnetometer data. We propose that lobe intervals can be well identified as times when the magnetic field is strong and relatively invariant, defined using thresholds in the magnitude of BX and the standard deviation Ď of the magnetic field magnitude. Using data from the Cluster spacecraft at downtail distances greater than 8 RE during 2001â2009, we find that thresholds of 30 nT and 3.5 nT, respectively, optimize agreement with a previous, independently derived lobe identification method that used both magnetic and plasma data over the same interval. Specifically, our method has a moderately high accuracy (66%) and a low probability of false detection (11%) in comparison to the other method. Furthermore, our method identifies the lobe on many other occasions when the previous method was unable to make any identification and yields longer continuous intervals in the lobe than the previous method, with intervals at the 90th percentile being triple the length. Our method also allows for analyses of the lobes outside the time span of the previous method
Fetal growth trajectories and measures of insulin resistance in young adults
Context: Events during gestation greatly influence the risk of cardiometabolic diseases including diabetes in offspring during later life. Objective: This study aimed to investigate relationships between serial ultrasound-derived fetal growth trajectories and markers of insulin resistance in young adults in the Raine Study, an Australian pregnancy cohort. Methods: Linear mixed modeling examined the relationship between fetal growth trajectory groups, constructed using serial ultrasound-based abdominal circumference (AC), femur length (FL), and head circumference (HC) from 1333 mother-fetal pairs, and offspring Homeostatic Model Assessment of Insulin Resistance (HOMA-IR), as a marker of diabetes risk, at 20 (n = 414), 22 (n = 385), and 27 (n = 431) years. Analyses were adjusted for age, sex, ethnicity, socioeconomic status, adult lifestyle factors, and maternal factors during pregnancy. Results: The study identified 7 AC, 5 FL, and 5 HC growth trajectory groups. Compared to the average-stable (reference) group, a low-falling AC growth trajectory (26%; P = .005) and 2 low HC growth trajectories (20%; P = .006% and 8%; P = .021) were associated with higher adult HOMA-IR. Trajectories representing a high-stable FL and a rising HC were associated with 12% (P = .002) and 9% (P = .021) lower adult HOMA-IR, respectively, compared to the reference group. Conclusion: Restricted fetal HC and AC from early pregnancy are associated with higher relative insulin resistance in the offspring during adulthood. These data strengthen our understanding of the importance of the intrauterine environment and its effect on the risk of predisposition to adult diabetes and related metabolic disorders
Relationships between intrauterine fetal growth trajectories and markers of adiposity and inflammation in young adults
Background: There is now good evidence that events during gestation significantly influence the developmental well-being of an individual in later life. This study aimed to investigate the relationships between intrauterine growth trajectories determined by serial ultrasound and subsequent markers of adiposity and inflammation in the 27-year-old adult offspring from the Raine Study, an Australian longitudinal pregnancy cohort. Methods: Ultrasound fetal biometric measurements including abdominal circumference (AC), femur length (FL), and head circumference (HC) from 1333 mother-fetal pairs (Gen1âGen2) in the Raine Study were used to develop fetal growth trajectories using group-based trajectory modeling. Linear mixed modeling investigated the relationship between adult body mass index (BMI), waist circumference (WC), and high-sensitivity C-reactive protein (hs-CRP) of Gen2 at 20 (n = 485), 22 (n = 421) and 27 (n = 437) years and the fetal growth trajectory groups, adjusting for age, sex, adult lifestyle factors, and maternal factors during pregnancy. Results: Seven AC, five FL and five HC growth trajectory groups were identified. Compared to the average-stable (reference) group, a lower adult BMI was observed in two falling AC trajectories: (β = â1.45 kg/m2, 95% CI: â2.43 to â0.46, P = 0.004) and (β = â1.01 kg/m2, 95% CI: â1.96 to â0.05, P = 0.038). Conversely, higher adult BMI (2.58 kg/m2, 95% CI: 0.98 to 4.18, P = 0.002) and hs-CRP (37%, 95% CI: 9â73%, P = 0.008) were observed in a rising FL trajectory compared to the reference group. A high-stable HC trajectory associated with 20% lower adult hs-CRP (95% CI: 5â33%, P = 0.011). Conclusion: This study highlights the importance of understanding causes of the unique patterns of intrauterine growth. Different fetal growth trajectories from early pregnancy associate with subsequent adult adiposity and inflammation, which predispose to the risk of diabetes and cardiometabolic disease
Role of Sigma-1 Receptors in Neurodegenerative Diseases
Neurodegenerative diseases with distinct genetic etiologies and pathological phenotypes appear to share common mechanisms of neuronal cellular dysfunction, including excitotoxicity, calcium dysregulation, oxidative damage, ER stress and mitochondrial dysfunction. Glial cells, including microglia and astrocytes, play an increasingly recognized role in both the promotion and prevention of neurodegeneration. Sigma receptors, particularly the sigma-1 receptor subtype, which are expressed in both neurons and glia of multiple regions within the central nervous system, are a unique class of intracellular proteins that can modulate many biological mechanisms associated with neurodegeneration. These receptors therefore represent compelling putative targets for pharmacologically treating neurodegenerative disorders. In this review, we provide an overview of the biological mechanisms frequently associated with neurodegeneration, and discuss how sigma-1 receptors may alter these mechanisms to preserve or restore neuronal function. In addition, we speculate on their therapeutic potential in the treatment of various neurodegenerative disorders
The impact of a needsâbased model of care on accessibility and quality of care within children's mental health services: A qualitative investigation of the UK iâTHRIVE Programme
Abstract: Background: The iâTHRIVE Programme is a needsâbased model of care, based on the THRIVE Framework, that is being implemented across the United Kingdom with the aim of improving outcomes for children and young people's mental health and wellbeing. This study aimed to investigate the impact that this programme has on accessibility and quality of care, as viewed by key stakeholders. Methods: Interviews with professionals and service users were conducted during the implementation of the THRIVE Framework in four sites of one mental health and community service provider. Results: Three themes are identified: âimpact of needsâbased groupings on referralâ, âimpact of collaborative and interagency approachâ and âimpact of iâTHRIVE on clinical practiceâ. Findings suggest that accessibility was seen to be promoted through the integration of a needsâbased approach, flexible reâreferral, signposting and information sharing, the use of goalâorientated interventions and collaboration over risk and treatment endings. Shared decision making was perceived to improve the experience of care for young people, as was interagency working. Goalâfocused interventions and upfront discussion of treatment endings were seen to help clinicians manage expectations and discharge but could also compromise effectiveness and engagement. Obstacles to impact were resistance to interagency working and a shortage of resources across the system. Conclusions: iâTHRIVE is a promising approach with the potential to facilitate the accessibility and quality of mental health care. However, a tension exists between enhancing accessibility and quality of care, which points towards the importance of outcome and satisfaction monitoring. Obstacles to impact point to the importance of a wholeâsystem approach supported by sufficient resources across the locality
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The impact of a needsâbased model of care on accessibility and quality of care within children's mental health services: A qualitative investigation of the UK iâTHRIVE Programme
Abstract: Background: The iâTHRIVE Programme is a needsâbased model of care, based on the THRIVE Framework, that is being implemented across the United Kingdom with the aim of improving outcomes for children and young people's mental health and wellbeing. This study aimed to investigate the impact that this programme has on accessibility and quality of care, as viewed by key stakeholders. Methods: Interviews with professionals and service users were conducted during the implementation of the THRIVE Framework in four sites of one mental health and community service provider. Results: Three themes are identified: âimpact of needsâbased groupings on referralâ, âimpact of collaborative and interagency approachâ and âimpact of iâTHRIVE on clinical practiceâ. Findings suggest that accessibility was seen to be promoted through the integration of a needsâbased approach, flexible reâreferral, signposting and information sharing, the use of goalâorientated interventions and collaboration over risk and treatment endings. Shared decision making was perceived to improve the experience of care for young people, as was interagency working. Goalâfocused interventions and upfront discussion of treatment endings were seen to help clinicians manage expectations and discharge but could also compromise effectiveness and engagement. Obstacles to impact were resistance to interagency working and a shortage of resources across the system. Conclusions: iâTHRIVE is a promising approach with the potential to facilitate the accessibility and quality of mental health care. However, a tension exists between enhancing accessibility and quality of care, which points towards the importance of outcome and satisfaction monitoring. Obstacles to impact point to the importance of a wholeâsystem approach supported by sufficient resources across the locality
Associations between prenatal exposure to phthalates and features of the metabolic syndrome in males from childhood into adulthood
Phthalate metabolites are detectable within the majority of the population. Evidence suggests that a prenatal exposure to phthalates may be associated with the subsequent risks of obesity and elevated blood pressure. We hypothesised that a prenatal exposure to phthalates would lead to an increase in adverse cardiometabolic parameters through childhood and adulthood. The maternal serum phthalate measurements from the stored samples taken from Gen1 mothers at 18 and 34 weeks gestation were examined in relation to the cardiometabolic measures in 387 male offspring from the Raine Study. Data from the Gen2 follow-ups between 3 and 27 years were used. The primary outcomes were analysed longitudinally using linear mixed models for the repeated measures. Non-alcoholic fatty liver disease (NAFLD) was assessed at 17 years using logistic regression. A consistent positive relationship was observed between a prenatal exposure to mono-carboxy-iso-octyl phthalate (MCiOP) through adolescence into adulthood with systolic blood pressure. There were no other consistent cardiovascular associations. Mid-levels of prenatal exposures to Mono-n-butyl phthalate (MnBP) were associated with a greater incidence of NAFLD. Detectable Mono-3-carboxypropyl phthalate (MCPP) was associated with a lower serum HDL-C through late childhood into adulthood, while a higher prenatal exposure to mono-iso-butyl phthalate (MiBP), was associated with a higher LDL-C at 22 years of age. A mid-level prenatal exposure to mono-2-ethylhexyl phthalate (MEHP) metabolites was associated with higher insulin in adulthood, while a higher prenatal exposure to the sum of the Di-(2-ethyl-hexyl) phthalate (DEHP) and Di-iso-nonyl phthalate (DiNP) metabolites was associated with higher fasting serum glucose in adulthood. In conclusion, our study demonstrated that higher prenatal phthalate exposures to some phthalate metabolites was associated with some adverse metabolic profiles through adolescence into adulthood, although the consistent themes were limited to a few metabolites and the outcomes of systolic blood pressure, fasting insulin and glucose
Poster abstract: Discovering Bioactive Compounds For Bone Growth: The Osteogenicity Of Marine Organism-derived Extracts
Tailward propagation of magnetic energy density variations With respect to substorm onset times
During geomagnetic substorms, around 1015 J of energy is extracted from the solar wind and processed by the Earth's magnetosphere. Prior to the onset of substorm expansion phases, this energy is thought to be largely stored as an increase in the magnetic field in the magnetotail lobes. However, how, when, and where this energy is stored and released within the magnetotail is unclear. Using data from the Cluster spacecraft and substorm onsets from Substorm Onsets and Phases from Indices of the Electrojet (SOPHIE), we examine the variation in the lobe magnetic energy density with respect to substorm onset for 541 isolated onsets. Based on a crossâcorrelation analysis and a simple model, we deduce the following: On average, the magnetic energy density increases approximately linearly in the hour preceding onset and decreases at a similar rate after onset. The timing and magnitude of these changes varies with downtail distance, with observations from the midâtail ( urn:x-wiley:jgra:media:jgra54303:jgra54303-math-0001) showing larger changes in the magnetic energy density that occur âź20 min after changes in the nearâtail ( urn:x-wiley:jgra:media:jgra54303:jgra54303-math-0002). The decrease in energy density in the nearâtail region is observed before the ground onset identified by SOPHIE, implying that the substorm is driven from the magnetotail and propagates into the ionosphere. The implication of these results is that energy in the nearâtail region is released first during the substorm expansion phase, with energy conversion propagating away from the Earth with time
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Increases in plasma sheet temperature with solar wind driving during substorm growth phases
During the substorm growth phase, magnetic reconnection extracts ~10^15 J from the solar wind through magnetic reconnection at the magnetopause, which is then stored in the magnetotail lobes. Plasma sheet pressure then increases to balance magnetic flux density increases in the lobes. We examine plasma sheet pressure, density and temperature during substorm growth phases using nine years of Cluster data (>316,000 data points). We show that plasma sheet pressure and temperature are higher during growth phases with higher solar wind driving whereas the density is approximately constant. We also show a weak correlation between plasma sheet temperature before onset and the minimum SuperMAG SML auroral index in the subsequent substorm. We discuss how energization of the plasma sheet before onset may result from thermodynamically adiabatic processes; how hotter plasma sheets may result in magnetotail instabilities and how this relates to the onset and size of the subsequent substorm expansion phase
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