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Gravitational waves from coalescing neutron stars encode information about nuclear matter at extreme densities, inaccessible by laboratory experiments. The late inspiral is influenced by the presence of tides, which depend on the neutron star equation of state. Neutron star mergers are expected to often produce rapidly rotating remnant neutron stars that emit gravitational waves. These will provide clues to the extremely hot post-merger environment. This signature of nuclear matter in gravitational waves contains most information in the 2–4 kHz frequency band, which is outside of the most sensitive band of current detectors. We present the design concept and science case for a Neutron Star Extreme Matter Observatory (NEMO): a gravitational-wave interferometer optimised to study nuclear physics with merging neutron stars. The concept uses high-circulating laser power, quantum squeezing, and a detector topology specifically designed to achieve the high-frequency sensitivity necessary to probe nuclear matter using gravitational waves. Above 1 kHz, the proposed strain sensitivity is comparable to full third-generation detectors at a fraction of the cost. Such sensitivity changes expected event rates for detection of post-merger remnants from approximately one per few decades with two A+ detectors to a few per year and potentially allow for the first gravitational-wave observations of supernovae, isolated neutron stars, and other exotica.
The SPARC tokamak is a critical next step towards commercial fusion energy. SPARC is designed as a high-field ($B_0 = 12.2$ T), compact ($R_0 = 1.85$ m, $a = 0.57$ m), superconducting, D-T tokamak with the goal of producing fusion gain $Q>2$ from a magnetically confined fusion plasma for the first time. Currently under design, SPARC will continue the high-field path of the Alcator series of tokamaks, utilizing new magnets based on rare earth barium copper oxide high-temperature superconductors to achieve high performance in a compact device. The goal of $Q>2$ is achievable with conservative physics assumptions ($H_{98,y2} = 0.7$) and, with the nominal assumption of $H_{98,y2} = 1$, SPARC is projected to attain $Q \approx 11$ and $P_{\textrm {fusion}} \approx 140$ MW. SPARC will therefore constitute a unique platform for burning plasma physics research with high density ($\langle n_{e} \rangle \approx 3 \times 10^{20}\ \textrm {m}^{-3}$), high temperature ($\langle T_e \rangle \approx 7$ keV) and high power density ($P_{\textrm {fusion}}/V_{\textrm {plasma}} \approx 7\ \textrm {MW}\,\textrm {m}^{-3}$) relevant to fusion power plants. SPARC's place in the path to commercial fusion energy, its parameters and the current status of SPARC design work are presented. This work also describes the basis for global performance projections and summarizes some of the physics analysis that is presented in greater detail in the companion articles of this collection.
SPARC is designed to be a high-field, medium-size tokamak aimed at achieving net energy gain with ion cyclotron range-of-frequencies (ICRF) as its primary auxiliary heating mechanism. Empirical predictions with conservative physics indicate that SPARC baseline plasmas would reach $Q\approx 11$, which is well above its mission objective of $Q>2$. To build confidence that SPARC will be successful, physics-based integrated modelling has also been performed. The TRANSP code coupled with the theory-based trapped gyro-Landau fluid (TGLF) turbulence model and EPED predictions for pedestal stability find that $Q\approx 9$ is attainable in standard H-mode operation and confirms $Q > 2$ operation is feasible even with adverse assumptions. In this analysis, ion cyclotron waves are simulated with the full wave TORIC code and alpha heating is modelled with the Monte–Carlo fast ion NUBEAM module. Detailed analysis of expected turbulence regimes with linear and nonlinear CGYRO simulations is also presented, demonstrating that profile predictions with the TGLF reduced model are in reasonable agreement.
Obsessive compulsive disorder (OCD) is observed at increased rates in first-degree relatives of probands with autism spectrum disorders (ASDs). In addition, OCD-like traits are observed in autism, and in Asperger syndrome. Furthermore, subjects with OCD may have traits that overlap with some aspects of higher functioning ASDs. These observations suggest that OCD and ASDs may share some genetic risk factors. In support of this, it has recently been suggested that both common and rare functional variants in the serotonin transporter (SLC6A4) may increase risk for OCD and/or ASD. We will review our large-scale analysis of common and rare functional variants SLC6A4 in ASDs and relate these results to studies of OCD. In parallel studies, we have carried our linkage analysis in families with ASDs, focusing on those with more severe OCD-like traits. These families demonstrated increased evidence for linkage to chromosomes 1, 6, and 19. Evidence for linkage to chromosomes 6 and 19 have been observed in other studies, which we will summarize. Finally, we have examined the evidence that common variants in the NrCAM, TPH1 and TPH2 genes are associated with ASDs, particularly in patients with more severe OCD-like traits, and these results will be summarized.
Obsessive-compulsive disorder (OCD) is a highly disabling condition, with frequent early onset. Adult/adolescent OCD has been extensively investigated, but little is known about prevalence and clinical characterization of geriatric patients with OCD (G-OCD = 65 years). The present study aimed to assess prevalence of G-OCD and associated socio-demographic and clinical correlates in a large international sample.
Methods:
Data from 416 outpatients, participating in the ICOCS network, were assessed and categorized into 2 groups, age < vs = 65 years, and then divided on the basis of the median age of the sample (age < vs = 42 years). Socio-demographic and clinical variables were compared between groups (Pearson Chi-squared and t tests).
Results:
G-OCD compared with younger patients represented a significant minority of the sample (6% vs 94%, P < .001), showing a significantly later age at onset (29.4 ± 15.1 vs 18.7 ± 9.2 years, P < .001), a more frequent adult onset (75% vs 41.1%, P < .001) and a less frequent use of cognitive-behavioural therapy (CBT) (20.8% vs 41.8%, P < .05). Female gender was more represented in G-OCD patients, though not at a statistically significant level (75% vs 56.4%, P = .07). When the whole sample was divided on the basis of the median age, previous results were confirmed for older patients, including a significantly higher presence of women (52.1% vs 63.1%, P < .05).
Conclusions:
G-OCD compared with younger patients represented a small minority of the sample and showed later age at onset, more frequent adult onset and lower CBT use. Age at onset may influence course and overall management of OCD, with additional investigation needed.
Lateral memristors consisting of planar Ag electrodes (with sub-micrometer separation) supported on thin films of amorphous zinc-tin-oxide have been characterized. After an initial filament-forming process, each device exhibited volatile, resistive switching. In the low resistance state, the transport mechanism and conductance depended on prior activity and on the imposed current limit, mimicking biologic synaptic plasticity. Microscopic observations performed on each device revealed nanoscale filaments between the electrodes. These filaments were subject to Rayleigh instability and exhibited relaxation times determined by their effective radii. The relaxation times and on:off resistance ratios suggest suitability for threshold switching selector devices.
Elevated circulating cholesterol levels are a risk factor for CVD which is also associated with sub-optimal vascular function. There is emerging evidence that anthocyanins can cause beneficial cardio-protective effects by favourably modulating lipoprotein profiles. We compared the effects of blood orange juice which is rich in anthocyanins and blonde orange juice without anthocyanins on LDL-cholesterol and other biomarkers of CVD risk, vascular function and glycaemia. In all, forty-one participants (aged 25–84 years) with a waist circumference >94 cm (men) and >80 cm (women) completed a randomised, open label, two-arm cross-over trial. For 28 d participants ingested (i) 500 ml blood orange juice providing 50 mg anthocyanins/d and (ii) 500 ml blonde orange juice without anthocyanins. There was a minimum 3-week washout period between treatments. LDL-cholesterol and other biomarkers associated with CVD risk and glycaemia were assessed at the start and end of each treatment period. No significant differences were observed in total, HDL- and LDL-cholesterol, TAG, glucose, fructosamine, nitric oxide, C-reactive protein, aortic systolic blood pressure and diastolic blood pressure or carotid-femoral and brachial-ankle pulse wave velocity after 28 d ingestion of blood orange juice compared with standard orange juice. The lack of effect on LDL-cholesterol may be due to the modest concentration of anthocyanins in the blood orange juice.
Oxidative stress has been linked to many obesity-related conditions among children including cardiovascular disease, diabetes mellitus and hypertension. Exposure to environmental chemicals such as phthalates, ubiquitously found in humans, may also generate reactive oxygen species and subsequent oxidative stress. We examined longitudinal changes of 8-isoprostane urinary concentrations, a validated biomarker of oxidative stress, and associations with maternal prenatal urinary concentrations of phthalate metabolites for 258 children at 5, 9 and 14 years of age participating in a birth cohort residing in an agricultural area in California. Phthalates are endocrine disruptors, and in utero exposure has been also linked to altered lipid metabolism, as well as adverse birth and neurodevelopmental outcomes. We found that median creatinine-corrected 8-isoprostane concentrations remained constant across all age groups and did not differ by sex. Total cholesterol, systolic and diastolic blood pressure were positively associated with 8-isoprostane in 14-year-old children. No associations were observed between 8-isoprostane and body mass index (BMI), BMI Z-score or waist circumference at any age. Concentrations of three metabolites of high molecular weight phthalates measured at 13 weeks of gestation (monobenzyl, monocarboxyoctyl and monocarboxynonyl phthalates) were negatively associated with 8-isoprostane concentrations among 9-year olds. However, at 14 years of age, isoprostane concentrations were positively associated with two other metabolites (mono(2-ethylhexyl) and mono(2-ethyl-5-carboxypentyl) phthalates) measured in early pregnancy. Longitudinal data on 8-isoprostane in this pediatric population with a high prevalence of obesity provides new insight on certain potential cardiometabolic risks of prenatal exposure to phthalates.
Finite element modelling has been used to optimise the current/ voltage (I/V) characteristics of metal/ n-SiC and metal/ n-Si diodes incorporating a thin interfacial layer. The electrical properties of the diodes have been examined in relation to the polytype of SiC (3H, 4H or 6C), the doping level, NA, (1015 - 1018cm3) of the substrate, the defect state density, Dit and the work function of the Schottky metal, Φm. The modelling by Technology Computer-Aided Design (TCAD) has shown that the presence of an interfacial insulating layer with a thickness of 1.0 nm has reduced the reverse leakage current of the diode by a factor of ∼102 in Si and 1013 (from 10-19 A to 10-6 A) for SiC with only a minor reduction (∼ 0.8 times) in the forward current in SiC. The properties of the diodes have been modelled at room temperature without thermal annealing.
Carbon films deposited by filtered cathodic vacuum arc have been used to form high quality Schottky diodes on p-Si. Energetic deposition with an applied substrate bias of -1 kV and with a substrate temperature of 100 °C has produced carbon diodes with rectification ratios of ∼ 3 × 106, saturation currents of ∼0.02 nA and ideality factors close to unity (n = 1.05). Simulations were used to estimate the effective work function and the thickness of an interfacial mixed (C/SiO2) layer from the current/voltage characteristics of the diodes.
ZnSe-based heterostructures grown on GaAs substrates have been investigated for use in pin-diode LED applications. In this study, a conventional Bragg-Brentano diffractometer (BBD) has been used to screen samples for phase identification, crystallite size, presence of polycrystalline ZnSe, and initial rocking curve (RC) analysis. A limitation of the conventional diffractometer is that the smallest RC full width at half maximum (FWHM) that can be achieved is 500 to 600 arc sec. As deposition parameters are optimized and the RC limit of the conventional diffractometer is reached, analysis is moved to a four-bounce high-resolution diffractometer (HRD). Although more time for analysis is required, using the HRD has a RC resolution advantage, where RCs of <20 arc sec are obtained for neat GaAs wafers. Combining the BBD and HRD instruments for analysis of ZnSe films grown on GaAs substrates allows for an efficient means of high sample throughput combined with an accurate measurement of film alignment.
Taxometric research methods were developed by Paul Meehl and colleagues to distinguish between categorical and dimensional models of latent variables. We have conducted a comprehensive review of published taxometric research that included 177 articles, 311 distinct findings and a combined sample of 533 377 participants. Multilevel logistic regression analyses have examined the methodological and substantive variables associated with taxonic (categorical) findings. Although 38.9% of findings were taxonic, these findings were much less frequent in more recent and methodologically stronger studies, and in those reporting comparative fit indices based on simulated comparison data. When these and other possible confounds were statistically controlled, the true prevalence of taxonic findings was estimated at 14%. The domains of normal personality, mood disorders, anxiety disorders, eating disorders, externalizing disorders, and personality disorders (PDs) other than schizotypal yielded little persuasive evidence of taxa. Promising but still not definitive evidence of psychological taxa was confined to the domains of schizotypy, substance use disorders and autism. This review indicates that most latent variables of interest to psychiatrists and personality and clinical psychologists are dimensional, and that many influential taxonic findings of early taxometric research are likely to be spurious.