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Long-duration gamma-ray burst (GRB) afterglow observations offer cutting-edge opportunities to characterise the star formation history of the Universe back to the epoch of reionisation, and to measure the chemical composition of interstellar and intergalactic gas through absorption spectroscopy. The main barrier to progress is the low efficiency in rapidly and confidently identifying which bursts are high redshift (
$z > 5$
) candidates before they fade, as this requires low-latency follow-up observations at near-infrared wavelengths (or longer) to determine a reliable photometric redshift estimate. Since no current or planned gamma-ray observatories carry near-infrared telescopes on-board, complementary facilities are needed. So far this task has been performed by instruments on the ground, but sky visibility and weather constraints limit the number of GRB targets that can be observed and the speed at which follow-up is possible. In this work we develop a Monte Carlo simulation framework to investigate an alternative approach based on the use of a rapid-response near-infrared nano-satellite, capable of simultaneous imaging in four bands from
$0.8$
to
$1.7\,\unicode{x03BC}$
m (a mission concept called SkyHopper). Using as reference a sample of 88 afterglows observed with the GROND instrument on the MPG/ESO telescope, we find that such a nano-satellite is capable of detecting in the H-band (1.6
$\unicode{x03BC}$
m)
$72.5\% \pm 3.1\%$
of GRBs concurrently observable with the Swift satellite via its UVOT instrument (and
$44.1\% \pm 12.3\%$
of high redshift (
$z>5$
) GRBs) within 60 min of the GRB prompt emission. This corresponds to detecting
${\sim}55$
GRB afterglows per year, of which 1–3 have
$z > 5$
. These rates represent a substantial contribution to the field of high-z GRB science, as only 23
$z > 5$
GRBs have been collectively discovered by the entire astronomical community over the last
${\sim}24$
yr. Future discoveries are critically needed to take advantage of next generation follow-up spectroscopic facilities such as 30m-class ground telescopes and the James Webb Space Telescope. Furthermore, a systematic space-based follow-up of afterglows in the near-infrared will offer new insight on the population of dusty (‘dark’) GRBs which are primarily found at cosmic noon (
$z\sim 1-3$
). Additionally, we find that launching a mini-constellation of 3 near-infrared nano-satellites would increase the detection fraction of afterglows to
${\sim}83\%$
and substantially reduce the latency in the photometric redshift determination.
Sleep and circadian timing shifts later during adolescence, conflicting with early school start times, and resulting in circadian misalignment. Although circadian misalignment has been linked to depression, substance use, and altered reward function, a paucity of experimental studies precludes the determination of causality. Here we tested, for the first time, whether experimentally-imposed circadian misalignment alters the neural response to monetary reward and/or response inhibition.
Methods
Healthy adolescents (n = 25, ages 13–17) completed two in-lab sleep schedules in counterbalanced order: An ‘aligned’ condition based on typical summer sleep-wake times (0000–0930) and a ‘misaligned’ condition mimicking earlier school year sleep-wake times (2000–0530). Participants completed morning and afternoon functional magnetic resonance imaging scans during each condition, including monetary reward (morning only) and response inhibition (morning and afternoon) tasks. Total sleep time and circadian phase were assessed via actigraphy and salivary melatonin, respectively.
Results
Bilateral ventral striatal (VS) activation during reward outcome was lower during the Misaligned condition after accounting for the prior night's total sleep time. Bilateral VS activation during reward anticipation was lower during the Misaligned condition, including after accounting for covariates, but did not survive correction for multiple comparisons. Right inferior frontal gyrus activation during response inhibition was lower during the Misaligned condition, before and after accounting for total sleep time and vigilant attention, but only during the morning scan.
Conclusions
Our findings provide novel experimental evidence that circadian misalignment analogous to that resulting from school schedules may have measurable impacts on healthy adolescents' reward processing and inhibition of prepotent responses.
Post-traumatic stress disorder (PTSD) is a psychiatric disorder that may develop following exposure to a potentially traumatic event. In developing our understanding of PTSD, identifying potential differences in prevalence, development, maintenance, and prognosis between sexes (Olff, 2017; Breslau, 2002) has been of great interest. Many theories and models have been developed to try to explain sex differences, and improve understanding, treatment, and recovery from this disorder. This chapter provides a snapshot of the current state of knowledge of PTSD with a special focus on the disorder in men, as well as providing insight into future directions and innovative approaches for studying and treating PTSD.
Available data suggest that sex hormone levels during puberty may affect symptom onset and expression, treatment responsiveness and outcomes in schizophrenia, whereas post-pubertal adolescents may have a similar clinical presentation and treatment response compared to adults with schizophrenia.
Objectives
Post-hoc analyses were conducted to assess the similarity of short- and long-term efficacy between post-pubertal adolescents and adults with schizophrenia treated with aripiprazole.
Methods
Based on available European epidemiologic data, a cut-off age of 15 years was used to isolate a subgroup of mostly post-pubertal adolescents with schizophrenia in aripiprazole clinical studies. Outcome measures from this subgroup (ages 15-17; n=147) were then compared to outcomes from one adult study (n=853) on short and long-term measures of efficacy, including PANSS scores, response rates, and remission rates.
Results
Comparable short and long-term treatment effects were observed on the PANSS total and subscale scores, demonstrated by overlapping 95% confidence intervals (mean change from baseline in PANSS total score (OC dataset): at week 6 in adults: -27,7; in adolescents 15-17 yr: -29,6; at week 30 in adults: -39,2; in adolescents 15-17 yr: -36). Percent of adolescents achieving response (defined as ≥ 30% decrease in PANSS total score from baseline) at 32 weeks (80,2%) on open label treatment was similar to that in adult studies at week 34 (80%) on double blind treatment (OC dataset).
Conclusions
Adolescents with schizophrenia (ages 15-17, mostly post-pubertal) demonstrate a positive treatment response in short-term and long-term studies which is similar to that observed in the adult patient population.
To evaluate the efficacy of aripiprazole adjunctive antidepressant therapy (ADT) with regard to functioning in patients with major depressive disorder (MDD) who did not achieve an adequate response with standard ADT.
Methods
Pooled data were analyzed from three nearly identically designed randomized, double-blind, placebo-controlled trials: CN138-139, CN138-163 and CN138-165. These included patients with MDD, without psychotic features, who had failed at least one ADT treatment in the present episode. Patients completing an 8-week prospective ADT phase with inadequate response were randomized to 6-weeks’ treatment with adjunctive aripiprazole (n=508) or placebo (n=494). Functioning was assessed using the Sheehan Disability Scale (SDS). Comparisons of mean change from baseline in total SDS score, and domains of family life, social life and work/school were performed using ANCOVA.
Results
Adjunctive aripiprazole produced significant improvements in total SDS (-1.2 on an adjusted scale of 1-10, with 10=worst level of functioning/1=best) vs adjunctive placebo (-0.7, p< 0.001). Adjunctive aripiprazole produced significant changes in the family life domain (-1.4 for adjunctive aripiprazole vs -0.7 for adjunctive placebo, p< 0.001) and the social life domain (-1.4 for adjunctive aripiprazole vs -0.7 for adjunctive placebo, p< 0.001). No difference between groups was observed on the work/school domain (-0.8 for adjunctive aripiprazole and -0.6 for adjunctive placebo, p=0.34).
Conclusions
Adjunctive aripiprazole showed significant improvements in overall SDS scores, and family and social life domains. Less change was observed in the work/school domain. The results emphasize that assessment of patient functioning may have utility both in clinical trials and clinical practice.
Optimal management of schizophrenia in adolescents is limited by the lack of available therapies. The efficacy and tolerability of aripiprazole was investigated in this patient population.
Methods:
This 6-week, randomized, double-blind, placebo controlled trial was conducted at 101 international centers, with a safety monitoring board. 13-17 year-olds with a DSM-IV diagnosis of schizophrenia were randomized to placebo, or a fixed dose of aripiprazole 10 mg or 30 mg reached after a 5 or 11 day titration, respectively. The primary endpoint was mean change from baseline on the PANSS Total score at week 6. Secondary endpoints included the PANSS Positive and Negative subscales, and CGI Improvement score. Tolerabilility assessements included frequency and severity of adverse events, as well as blood chemistries, metabolic parameters and weight gain.
Results:
Over 85% of 302 patients completed this study. Both 10 mg and 30 mg doses were superior to placebo on the primary endpoint (PANSS total), with significant differences observed as early as Week 1 (30mg). Both doses showed significant improvement on the PANSS Positive and CGI-I scales; and the 10 mg dose group was superior on PANSS Negative score. Approximately 5% of aripiprazole patients discontinued due to AEs. Weight gain and changes in prolactin were minimal.
Conclusions:
10mg and 30mg doses of aripiprazole were superior to placebo in the treatment of adolescents with schizophrenia. Aripiprazole was well tolerated, in general, with few discontinuations due to AEs. EPS was the most common AE. Change in body weight was similar to placebo.
There is limited published data from long-term pediatric bipolar clinical trials with which to guide appropriate treatment decisions. Long-term efficacy and safety of aripiprazole was investigated in this patient population.
Methods:
296 youths, ages 10-17 year-old with a DSM-IV diagnosis of bipolar I disorder were randomized to receive either placebo or aripiprazole (10mg or 30mg) in a 4-week double-blind trial. Completers continued assigned treatments for an additional 26 weeks (double-blind). Efficacy endpoints included mean change from baseline to week 4 and week 30 on the Young Mania Rating Scale; Children's Global Assessment Scale, Clinical Global Impressions-Bipolar version severity scale, General Behavior Inventory, Attention Deficit Hyperactivity Disorders Rating Scale, and time to discontinuation. Tolerability/safety assessments included incidence and severity of AEs, blood chemistries and metabolic parameters.
Results:
Over the 30-week course of double-blind treatment, aripiprazole (10 mg and 30 mg) was superior to placebo as early as week 1 (p< 0.002) and at all scheduled visits from week 2 through week 30 on mean change from baseline in the Y-MRS total score (p<.0001; all visits). Significant improvements were observed on multiple endpoints including the CGAS, GBI, CGI-BP, ADHD-RS-IV total score, time to discontinuation, and response and remission rates. The 3 most common AEs were somnolence, extrapyramidal disorder, and fatigue. Mean change in body weight z-scores over 30 weeks was not clinically significant.
Conclusions:
Over 30-weeks of treatment, both doses of aripiprazole were superior to placebo in the long term treatment of pediatric bipolar patients. Aripiprazole was generally well tolerated.
Detailed representation of ingesta inflow to and digesta outflow from the rumen is critical for improving the modelling of rumen function and herbage intake of grazing ruminants. The objective of the current work was to extend a mechanistic model of a grazing ruminant, MINDY, to simulate the dynamic links between ingestive and digestive processes as affected by forage and sward features (e.g. sward structure, herbage chemical composition) as well as the internal state of the animal. The work integrates existing aspects of forage ingestion, oral physiology and rumen digestion that influence ingesta characteristics and digesta outflows from the rumen, respectively. The paper describes the structure and function of the new development, assessing the new model in terms of dynamic changes of oral processing of ingesta and rumen dilution rate under different grazing contexts. MINDY reproduces characteristics of ingesta inflow to and digesta outflow from the rumen of grazing ruminants, achieving temporal patterns of occurrence within and between meals, similar to those for grazing animals reported in the literature. The model realistically simulates changes in particle size distribution of the ingestive bolus, bolus weight and rumen dilution rate in response to contrasting grazing management regimes. The new concepts encoded in MINDY capture the underlying biological mechanisms that drive the dynamic link between ingestion and digestion patterns. This development advances in the understanding and modelling of grazing and digestive behaviour patterns of free-ranging ruminants.
Measurement of water consumption and urinary nitrogen (UN) excretion of individual grazing ruminants is difficult, time-consuming and expensive. Therefore, prediction and modelling are critical for research to improve N and water use efficiency. The objective of the current work was to use a mechanistic model of a grazing ruminant, MINDY, to represent drinking and urination diurnal patterns, and the resulting pattern of UN excretion. This work is primarily an integration of existing knowledge of basic urination physiology and water dynamics in ruminants. MINDY reproduces observed patterns of urination achieving the correct temporal occurrence, relative volumes and nitrogen (N) concentration of individual urination events for a grazing dairy cow, comparable with those reported in the literature. The model simulates daily water imbibed and UN realistically, as well as ingestion rates for herbages with different protein content and contrasting grazing managements. Results of a cross-validation indicate that the root mean square prediction error and mean absolute error as % of the observed mean, respectively, were 26 and 23% for daily water imbibed, 26 and 27% for urination volume, and 25 and 19% for the frequency of urination. Although further parameterization and validation are needed, for a new development in an exploratory model like MINDY, these numbers are encouraging and reflect that the concepts encoded capture many of the underlying biological mechanisms that drive the diurnal pattern and daily UN excretion, as well as thirst, acceptable.
Anomalous drainage of the right superior caval vein into the left atrium is a rare congenital anomaly that causes cyanosis and occult infection owing to right-to-left shunting. Transcatheter management of this anomaly is unique and rarely reported. We report a 32-year-old man with a history of brain abscess, who was diagnosed with an anomalous right superior caval vein draining to the left atrium; right upper pulmonary vein and right middle pulmonary vein draining into the inferior portion of the right superior caval vein; and a left superior caval vein draining into the right atrium through the coronary sinus without a bridging vein. Pre-procedural planning was guided by three-dimensional printed model. The right superior caval vein was occluded with a 16-mm Amplatzer muscular Ventricular Septal Defect occluder inferior to the azygous vein, but superior to the entries of right upper and middle pulmonary veins. This diverted the right superior caval vein flow to the inferior caval vein system through the azygos vein in a retrograde manner and allowed the right upper pulmonary vein and right middle pulmonary vein flow to drain into the left atrium normally, achieving exclusion of right-to-left shunting and allowing normal drainage of pulmonary veins into the left atrium. At the 6-month follow-up, his saturation improved from 93 to 97% with no symptoms of superior caval vein syndrome.
To determine the patterns and predictors of treatment response trajectories for veterans with post-traumatic stress disorder (PTSD).
Methods
Conditional latent growth mixture modelling was used to identify classes and predictors of class membership. In total, 2686 veterans treated for PTSD between 2002 and 2015 across 14 hospitals in Australia completed the PTSD Checklist at intake, discharge, and 3 and 9 months follow-up. Predictor variables included co-morbid mental health problems, relationship functioning, employment and compensation status.
Results
Five distinct classes were found: those with the most severe PTSD at intake separated into a relatively large class (32.5%) with small change, and a small class (3%) with a large change. Those with slightly less severe PTSD separated into one class comprising 49.9% of the total sample with large change effects, and a second class comprising 7.9% with extremely large treatment effects. The final class (6.7%) with least severe PTSD at intake also showed a large treatment effect. Of the multiple predictor variables, depression and guilt were the only two found to predict differences in response trajectories.
Conclusions
These findings highlight the importance of assessing guilt and depression prior to treatment for PTSD, and for severe cases with co-morbid guilt and depression, considering an approach to trauma-focused therapy that specifically targets guilt and depression-related cognitions.
Identifying youth who may engage in future substance use could facilitate early identification of substance use disorder vulnerability. We aimed to identify biomarkers that predicted future substance use in psychiatrically un-well youth.
Method
LASSO regression for variable selection was used to predict substance use 24.3 months after neuroimaging assessment in 73 behaviorally and emotionally dysregulated youth aged 13.9 (s.d. = 2.0) years, 30 female, from three clinical sites in the Longitudinal Assessment of Manic Symptoms (LAMS) study. Predictor variables included neural activity during a reward task, cortical thickness, and clinical and demographic variables.
Results
Future substance use was associated with higher left middle prefrontal cortex activity, lower left ventral anterior insula activity, thicker caudal anterior cingulate cortex, higher depression and lower mania scores, not using antipsychotic medication, more parental stress, older age. This combination of variables explained 60.4% of the variance in future substance use, and accurately classified 83.6%.
Conclusions
These variables explained a large proportion of the variance, were useful classifiers of future substance use, and showed the value of combining multiple domains to provide a comprehensive understanding of substance use development. This may be a step toward identifying neural measures that can identify future substance use disorder risk, and act as targets for therapeutic interventions.
Original studies published over the last decade regarding time trends in dementia report mixed results. The aims of the present study were to use linked administrative health data for the province of Saskatchewan for the period 2005/2006 to 2012/2013 to: (1) examine simultaneous temporal trends in annual age- and sex-specific dementia incidence and prevalence among individuals aged 45 and older, and (2) stratify the changes in incidence over time by database of identification.
Methods:
Using a population-based retrospective cohort study design, data were extracted from seven provincial administrative health databases linked by a unique anonymized identification number. Individuals 45 years and older at first identification of dementia between April 1, 2005 and March 31, 2013 were included, based on case definition criteria met within any one of four administrative health databases (hospital, physician, prescription drug, and long-term care).
Results:
Between 2005/2006 and 2012/2013, the 12-month age-standardized incidence rate of dementia declined significantly by 11.07% and the 12-month age-standardized prevalence increased significantly by 30.54%. The number of incident cases decreased from 3,389 to 3,270 and the number of prevalent cases increased from 8,795 to 13,012. Incidence rate reductions were observed in every database of identification.
Conclusions:
We observed a simultaneous trend of decreasing incidence and increasing prevalence of dementia over a relatively short 8-year time period from 2005/2006 to 2012/2013. These trends indicate that the average survival time of dementia is lengthening. Continued observation of these time trends is warranted given the short study period.
Both maternal obesity and disordered mood have adverse effects on pregnancy outcome. We hypothesized that maternal very severe obesity (SO) is associated with increased anxiety and depression (A&D) symptoms during pregnancy, with adverse effects on gestational weight gain (GWG), postpartum mood and postpartum weight retention (PPWR) and explored any mediation by circulating glucocorticoids.
Method.
We measured A&D symptoms with validated questionnaires at weeks 17 and 28 of pregnancy and 3 months postpartum in 135 lean [body mass index (BMI) ⩽25 kg/m2] and 222 SO (BMI ⩾40 kg/m2) pregnant women. Fasting serum cortisol was measured by radioimmunoassay; GWG and PPWR were recorded.
Results.
A&D symptoms were higher in the SO group during pregnancy and postpartum despite adjusting for multiple confounders including previous mental health diagnosis (p < 0.05), and were non-linearly correlated with total GWG (anxiety R2 = 0.06, p = 0.037; depression R2 = 0.09, p = 0.001). In the SO group only, increased maternal anxiety (β = 0.33, p = 0.03) and depression (β = 0.19, p = 0.04) symptoms at week 17 of pregnancy were associated with increased PPWR, independent of total GWG and breastfeeding. Anxiety symptoms at week 28 of pregnancy, but not depression, were non-linearly correlated with serum cortisol level at week 36 of pregnancy (R2 = 0.06, p = 0.02). Cortisol did not mediate the link between A&D symptoms and GWG.
Conclusions.
Maternal SO was associated with increased A&D symptoms, and with adverse effects on GWG and PPWR independent of circulating glucocorticoids. Strategies to optimize GWG and postpartum weight management in SO women should include assessment and management of maternal mood in early pregnancy.
Although post-traumatic stress disorder (PTSD) has been a focus of attention in 1990/1991 Gulf War veterans, the excess risk of depression has not been clearly identified. We investigated this through a systematic review and meta-analysis of studies comparing depression in Gulf War veterans to depression in a comparison group of non-deployed military personnel.
Method
Multiple electronic databases and grey literature were searched from 1990 to 2012. Studies were assessed for eligibility and risk of bias according to established criteria.
Results
Of 14 098 titles and abstracts assessed, 14 studies met the inclusion criteria. Gulf War veterans had over twice the odds of experiencing depression [odds ratio (OR) 2.28, 95% confidence interval (CI) 1.88–2.76] and dysthymia or chronic dysphoria (OR 2.39, 95% CI 2.0–2.86) compared to non-deployed military personnel. This finding was robust in sensitivity analyses, and to differences in overall risk of bias and psychological measures used.
Conclusions
Despite divergent methodologies between studies, depression and dysthymia were twice as common in Gulf War veterans and are important medical conditions for clinicians and policymakers to be aware of in managing Gulf War veterans’ health.
Sleep loss produces abnormal increases in reward seeking but the mechanisms underlying this phenomenon are poorly understood. The present study examined the influence of one night of sleep deprivation on neural responses to a monetary reward task in a sample of late adolescents/young adults.
Method
Using a within-subjects crossover design, 27 healthy, right-handed late adolescents/young adults (16 females, 11 males; mean age 23.1 years) underwent functional magnetic resonance imaging (fMRI) following a night of sleep deprivation and following a night of normal sleep. Participants' recent sleep history was monitored using actigraphy for 1 week prior to each sleep condition.
Results
Following sleep deprivation, participants exhibited increased activity in the ventral striatum (VS) and reduced deactivation in the medial prefrontal cortex (mPFC) during the winning of monetary reward, relative to the same task following normal sleep conditions. Shorter total sleep time over the five nights before the sleep-deprived testing condition was associated with reduced deactivation in the mPFC during reward.
Conclusions
These findings support the hypothesis that sleep loss produces aberrant functioning in reward neural circuitry, increasing the salience of positively reinforcing stimuli. Aberrant reward functioning related to insufficient sleep may contribute to the development and maintenance of reward dysfunction-related disorders, such as compulsive gambling, eating, substance abuse and mood disorders.
Lyme borreliosis (LB) is the most common arthropod-borne disease of humans in the Northern hemisphere. In Europe, the causative agent, Borrelia burgdorferi sensu lato complex, is principally vectored by Ixodes ricinus ticks. The aim of this study was to identify environmental factors influencing questing I. ricinus nymph abundance and B. burgdorferi s.l. infection in questing nymphs using a large-scale survey across Scotland. Ticks, host dung and vegetation were surveyed at 25 woodland sites, and climatic variables from a Geographical Information System (GIS) were extracted for each site. A total of 2397 10 m2 transect surveys were conducted and 13 250 I. ricinus nymphs counted. Questing nymphs were assayed for B. burgdorferi s.l. and the average infection prevalence was 5·6% (range 0·8–13·9%). More questing nymphs and higher incidence of B. burgdorferi s.l. infection were found in areas with higher deer abundance and in mixed/deciduous compared to coniferous forests, as well as weaker correlations with season, altitude, rainfall and ground vegetation. No correlation was found between nymph abundance and infection prevalence within the ranges encountered. An understanding of the environmental conditions associated with tick abundance and pathogen prevalence may be used to reduce risk of exposure and to predict future pathogen prevalence and distributions under environmental changes.
Human campylobacteriosis exhibits a distinctive seasonality in temperate regions. This paper aims to identify the origins of this seasonality. Clinical isolates [typed by multi-locus sequence typing (MLST)] and epidemiological data were collected from Scotland. Young rural children were found to have an increased burden of disease in the late spring due to strains of non-chicken origin (e.g. ruminant and wild bird strains from environmental sources). In contrast the adult population had an extended summer peak associated with chicken strains. Travel abroad and UK mainland travel were associated with up to 17% and 18% of cases, respectively. International strains were associated with chicken, had a higher diversity than indigenous strains and a different spectrum of MLST types representative of these countries. Integrating empirical epidemiology and molecular subtyping can successfully elucidate the seasonal components of human campylobacteriosis. The findings will enable public health officials to focus strategies to reduce the disease burden.