A liquid argon time projection chamber, constructed for the Argon Response to Ionization and Scintillation (ARIS) experiment, is exposed to the highly collimated and quasimonoenergetic LICORNE ...neutron beam at the Institut de Physique Nucléaire d’Orsay (IPNO) in order to study the scintillation response to nuclear and electronic recoils. An array of liquid scintillator detectors, arranged around the apparatus, tag scattered neutrons and select nuclear recoil energies in the 7, 120 keV energy range. The relative scintillation efficiency of nuclear recoils is measured to high precision at null field, and the ion-electron recombination probability is extracted for a range of applied electric fields. Single-scattered Compton electrons, produced by gammas emitted from the deexcitation of Li*7 in coincidence with the beam pulse, along with calibration gamma sources, are used to extract the recombination probability as a function of energy and electron drift field. The ARIS results are compared with three recombination probability parametrizations (Thomas-Imel, Doke-Birks, and PARIS), allowing for the definition of a fully comprehensive model of the liquid argon response to nuclear and electronic recoils down to the few-keV range. The constraints provided by ARIS to the liquid argon response at low energy allow the reduction of systematics affecting the sensitivity of dark matter search experiments based on liquid argon.
In this qualitative study we explored the experiences of women breastfeeding children over 12 months of age. Data were collected from 24 participants using semi-structured photo-elicitation ...interviews and photo-prompted online surveys. Participants took photographs of their extended breastfeeding experiences over one week and reflected on how the events depicted made them feel, and what they represented in terms of their experience. Data were analysed using Interpretative Phenomenological Analysis. Four themes were developed; parenting through breastfeeding: meeting the needs of my child, my body is not my own, social influences on the breastfeeding experience, and thinking about stopping: my choice or theirs? Findings highlight that extended breastfeeding was experienced as beneficial for both mother and child, promoting closeness, and bonding, and providing a valued parenting tool. However, some mothers reported conflict between their desire for child-led extended breastfeeding and the need to regain autonomy and control of their own bodies. The dangers of negative societal responses to extended breastfeeding and risks to mental health posed by cultural constructions of ‘ideal’ motherhood are discussed.
Worldwide, suicide is a leading cause of death. Although a sizable proportion of deaths by suicide may be preventable, it is well documented that despite major governmental and international ...investments in research, education and clinical practice suicide rates have not diminished and are even increasing among several at-risk populations. Although nonhuman animals do not engage in suicidal behavior amenable to translational studies, we argue that animal model systems are necessary to investigate candidate endophenotypes of suicidal behavior and the neurobiology underlying these endophenotypes. Animal models are similarly a critical resource to help delineate treatment targets and pharmacological means to improve our ability to manage the risk of suicide. In particular, certain pathophysiological pathways to suicidal behavior, including stress and hypothalamic-pituitary-adrenal axis dysfunction, neurotransmitter system abnormalities, endocrine and neuroimmune changes, aggression, impulsivity and decision-making deficits, as well as the role of critical interactions between genetic and epigenetic factors, development and environmental risk factors can be modeled in laboratory animals. We broadly describe human biological findings, as well as protective effects of medications such as lithium, clozapine, and ketamine associated with modifying risk of engaging in suicidal behavior that are readily translatable to animal models. Endophenotypes of suicidal behavior, studied in animal models, are further useful for moving observed associations with harmful environmental factors (for example, childhood adversity, mechanical trauma aeroallergens, pathogens, inflammation triggers) from association to causation, and developing preventative strategies. Further study in animals will contribute to a more informed, comprehensive, accelerated and ultimately impactful suicide research portfolio.
Patients with cranial diabetes insipidus (CDI) are at risk of developing both hypernatraemia and hyponatraemia, due to the condition itself or secondary to treatment with vasopressin-analogues or ...during administration of i.v. fluids. We aimed to assess the frequency and impact of dysnatraemias in the inpatient (INPT) and outpatient (OPT) setting in desmopressin-treated CDI, comparing those with normal thirst with those with abnormal thirst.
The study included 192 patients with cranial diabetes, who were identified from the Beaumont Pituitary Database, a tertiary referral centre. Retrospective case note audit was performed and the clinical and biochemical information of 147 patients with CDI were available for analysis.
A total of 4142 plasma sodium measurements for 137 patients with normal thirst, and 385 plasma sodium measurements for ten patients with abnormal thirst were analysed. In those with normal thirst, the most common OPT abnormality was mild hyponatraemia (pNa(+) 131-134 mmol/l) in 27%, while 14.6% had more significant hyponatraemia (pNa(+) ≤130 mmol/l). Of those patients with normal thirst, 5.8% were admitted due to complications directly related to hyponatraemia. Compared with patients with normal thirst, those with abnormal thirst were more likely to develop significant OPT hypernatraemia (20% vs 1.4%, P=0.02) and significant INPT hyponatraemia (50% vs 11.1%, P 0.02).
OPT management of CDI is complicated by a significant incidence of hyponatraemia. In contrast, OPT hypernatraemia is almost exclusively a complication seen in adipsic CDI, who also had more frequent INPT hyponatraemia. CDI associated with thirst disorder requires increased physician attention and patient awareness of potential complications.
This study was conducted to explore differences in gray and white matter density between bipolar and healthy comparison groups using voxel-based morphometry (VBM).
Brain magnetic resonance imaging ...was performed for 39 subjects with bipolar I disorder and 43 comparison subjects. Images were registered into a proportional stereotaxic space and segmented into gray matter, white mater, and cerebrospinal fluid. Statistical parametric mapping was used to calculate differences in gray and white matter density between groups.
Bipolar subjects had decreased gray matter density in left anterior cingulate gyrus (Brodmann’s area BA 32, 7.3% decrease), an adjacent left medial frontal gyrus (BA 10, 6.9% decrease), right inferior frontal gyrus (BA 47, 9.2% decrease), and right precentral gyrus (BA 44, 6.2% decrease), relative to comparison subjects.
The observation of a gray matter density decrease in the left anterior cingulate, which processes emotions, in bipolar subjects is consistent with prior reports that used region-of-interest analytic methods. Decreased gray matter density in the right inferior frontal gyrus, which processes nonverbal and intrinsic functions, supports nondominant hemisphere dysfunction as a component of bipolar disorder.
New experiments have been performed on the brittle compressive failure of columnar‐grained, first‐year sea ice with the S2 growth texture, harvested from the floating cover on the Arctic Ocean. The ...ice was proportionally loaded biaxially across the columns at –10°C at 1.5 × 10−2 s−1; i.e., within the regime of brittle behavior. The results, when combined with earlier measurements of tensile strength by Richter‐Menge and Jones (1993), allow the complete brittle failure envelope to be constructed. The envelope is symmetric about the loading path R = σ2/σ1 = 1, owing to the isotropic character of the material within the horizontal plane of the ice sheet, but is asymmetric with respect to the compressive‐compressive and tensile‐tensile quadrants, owing to the relative weakness of the material under tension. The compressive strength reaches a maximum along the loading path R ∼ 0.5. Terminal failure occurs through either splitting (unconfined loading), Coulombic shear faulting under lower confinement (R < 0.2) or spalling under higher confinement (0.2 < R ≤ 1). An integral component of compressive failure under low confinement is the internal friction coefficient: its value under the conditions of the experiments (μi = 0.92 ± 0.09) is deduced from the failure envelope. The internal friction coefficient is shown through postterminal failure measurements to be closely similar to the coefficient of friction at the onset of sliding along the Coulombic faults. Granite exhibits similar behavior. Modeling reveals that the terminal failure stress under low confinement can be reasonably well described in terms of the comb‐crack mechanism (Schulson et al., 1999; Renshaw and Schulson, 2001) of brittle compressive failure. Comparison with observations and measurements in the field indicate that the failure processes that operate on the smaller scale are similar to at least some of those that operate on the larger scale, implying that the physics of failure may be scale‐independent.
We present new constraints on sub-GeV dark-matter particles scattering off electrons based on 6780.0 kg d of data collected with the DarkSide-50 dual-phase argon time projection chamber. This ...analysis uses electroluminescence signals due to ionized electrons extracted from the liquid argon target. The detector has a very high trigger probability for these signals, allowing for an analysis threshold of three extracted electrons, or approximately 0.05 keVee. We calculate the expected recoil spectra for dark matter-electron scattering in argon and, under the assumption of momentum-independent scattering, improve upon existing limits from XENON10 for dark-matter particles with masses between 30 and 100 MeV/c^{2}.
We report on the search for dark matter weakly interacting massive particles (WIMPs) in the mass range below 10 GeV=c2 from the analysis of the entire dataset acquired with a low-radioactivity argon ...target by the DarkSide-50 experiment at Laboratori Nazionali del Gran Sasso. The new analysis benefits from more accurate calibration of the detector response, improved background model, and better determination of systematic uncertainties, allowing us to accurately model the background rate and spectra down to 0.06 keVer. A 90% C.L. exclusion limit for the spin-independent cross section of 3 GeV=c2 mass WIMP on nucleons is set at 6 × 10-43 cm2, about a factor 10 better than the previous DarkSide-50 limit. This analysis extends the exclusion region for spin-independent dark matter interactions below the current experimental constraints in the 1.2, 3.6 GeV=c2 WIMP mass range.
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