Summary Most women of reproductive age have some physical discomfort or dysphoria in the weeks before menstruation. Symptoms are often mild, but can be severe enough to substantially affect daily ...activities. About 5–8% of women thus suffer from severe premenstrual syndrome (PMS); most of these women also meet criteria for premenstrual dysphoric disorder (PMDD). Mood and behavioural symptoms, including irritability, tension, depressed mood, tearfulness, and mood swings, are the most distressing, but somatic complaints, such as breast tenderness and bloating, can also be problematic. We outline theories for the underlying causes of severe PMS, and describe two main methods of treating it: one targeting the hypothalamus-pituitary-ovary axis, and the other targeting brain serotonergic synapses. Fluctuations in gonadal hormone levels trigger the symptoms, and thus interventions that abolish ovarian cyclicity, including long-acting analogues of gonadotropin-releasing hormone (GnRH) or oestradiol (administered as patches or implants), effectively reduce the symptoms, as can some oral contraceptives. The effectiveness of serotonin reuptake inhibitors, taken throughout the cycle or during luteal phases only, is also well established.
Attendance and completion of weight loss intervention is associated with better weight loss outcomes; however, attrition is neither consistently reported nor comprehensively explored in the weight ...loss literature. A systematic review was undertaken to identify factors associated with attrition in weight loss interventions involving overweight or obese (body mass index ≥ 25) adults (18–65 years). Sixty‐one studies published before May 2011 and addressing factors associated with weight loss programme attrition were identified. Conclusions were limited by the large number of variables explored, the small number of studies exploring each variable, the large variety of study settings and methodologies used, the inconsistent reporting of results, and the conflicting findings across studies. A consistent set of predictors has not yet been identified. The majority of studies relied on pre‐treatment routinely collected data rather than variables selected because of their theoretical and/or empirical relationship with attrition. However, psychological and behavioural patient factors and processes associated with the treatment were more commonly associated with attrition than patient background characteristics. Future research should consider theoretically grounded social–psychological and behavioural processes as potential predictors of dropout. Identification of patients at risk of dropout will contribute to both the effectiveness and the cost‐effectiveness of weight loss interventions.
Previous research has identified how menstruation is an important factor in both attempted and completed suicides for women. The purpose of this review was to outline (a) the risk profile for ...suicidality in women who were identified to experience Premenstrual Dysphoric Disorder (PMDD), a condition characterized by severe physical and psychological changes that occur during the luteal menstrual phase, and (b) the implications of these findings for clinical practice. A systematic literature review was conducted using five databases to identify any peer-reviewed articles published between 1989 and 2019. Ten papers eligible for inclusion were identified: three pertaining to
suicide cognitions
, five to
suicide attempts
and two to both
cognitions
and
attempts
. Findings showed that suicidal thoughts, ideation, plans and attempts were strongly associated with experiences of PMDD and that these findings were independent of psychiatric co-morbidities. However, women with PMDD did not present with more severe risk profiles for suicide attempts (in terms of frequency, impulsivity and lethality) or make more frequent attempts during the luteal menstrual phase compared with suicide attempters without PMDD. Women with PMDD should be considered a high risk group for suicidality; thus, identifying and treating symptoms are vital in reducing suicide attempts. Implications for clinical practice are outlined in the discussion.
We propose that the behavioral theory of the firm perspective on R&D search requires modification when applied to "communitarian" cultures such as Japan because reciprocity and embeddedness can ...influence the search decision. When performance exceeds aspirations, communitarian-oriented firms are more inclined to use their privileged position to help their less fortunate stakeholders by engaging in additional R&D search that should yield greater payoffs for these stakeholders in the future. Our results indicate that while Japanese firms engage in "problemistic" search in a manner similar to what has been found in other contexts, they respond differently when performance exceeds expectations. We find that as performance rises above aspirations, communitarian-oriented firms raise R&D search to a greater extent than do firms that lack a communitarian orientation.
The electroreduction of carbon dioxide (CO2) to carbon monoxide (CO) is a promising strategy to utilize CO2 emissions while generating a high value product. Commercial CO2 electroreduction systems ...will require high current densities (>100 mA cm−2) as well as improved energetic efficiencies (EEs), achieved via high CO selectivity and lowered applied potentials. Here we report a silver (Ag)-based system that exhibits the lowest overpotential among CO2-to-CO electrolyzers operating at high current densities, 300 mV at 300 mA cm−2, with near unity selectivity. We achieve these improvements in voltage efficiency and selectivity via operation in a highly alkaline reaction environment (which decreases overpotentials) and system pressurization (which suppresses the generation of alternative CO2 reduction products), respectively. In addition, we report a new record for the highest half-cell EE (>80%) for CO production at 300 mA cm−2.
Abstract
In alkaline and neutral MEA CO
2
electrolyzers, CO
2
rapidly converts to (bi)carbonate, imposing a significant energy penalty arising from separating CO
2
from the anode gas outlets. Here we ...report a CO
2
electrolyzer uses a bipolar membrane (BPM) to convert (bi)carbonate back to CO
2
, preventing crossover; and that surpasses the single-pass utilization (SPU) limit (25% for multi-carbon products, C
2+
) suffered by previous neutral-media electrolyzers. We employ a stationary unbuffered catholyte layer between BPM and cathode to promote C
2+
products while ensuring that (bi)carbonate is converted back, in situ, to CO
2
near the cathode. We develop a model that enables the design of the catholyte layer, finding that limiting the diffusion path length of reverted CO
2
to ~10 μm balances the CO
2
diffusion flux with the regeneration rate. We report a single-pass CO
2
utilization of 78%, which lowers the energy associated with downstream separation of CO
2
by 10× compared with past systems.
Extended emission (EE) is a high-energy, early time rebrightening sometimes seen in the light curves of short gamma-ray bursts (GRBs). We present the first contiguous fits to the EE tail and the ...later X-ray plateau seen by the Swift mission, unified within a single model. Our central engine is a magnetar surrounded by a fall-back accretion disc, formed by either the merger of two compact objects or the accretion-induced collapse of a white dwarf. During the EE phase, material is accelerated to super-Keplarian velocities and ejected from the system by the rapidly rotating (P 1-10 ms) and very strong (1015 G) magnetic field in a process known as magnetic propellering. The X-ray plateau is modelled as magnetic dipole spin-down emission. We first explore the range of GRB phenomena that the propeller could potentially reproduce, using a series of template light curves to devise a classification scheme based on phenomology. We then obtain fits to the light curves of nine GRBs with EE, simultaneously fitting both the propeller and the magnetic dipole spin-down and finding typical disc masses of a few 10−3 M to a few 10−2 M. This is done for ballistic, viscous disc and exponential accretion rates. We find that the conversion efficiency from kinetic energy to EM emission for propellered material needs to be 10 per cent and that the best-fitting results come from an exponential accretion profile.
Calibration of X-ray absorption in our Galaxy Willingale, R.; Starling, R. L. C.; Beardmore, A. P. ...
Monthly Notices of the Royal Astronomical Society,
05/2013, Letnik:
431, Številka:
1
Journal Article
Recenzirano
Odprti dostop
Prediction of the soft X-ray absorption along lines of sight through our Galaxy is crucial for understanding the spectra of extragalactic sources, but requires a good estimate of the foreground ...column density of photoelectric absorbing species. Assuming uniform elemental abundances this reduces to having a good estimate of the total hydrogen column density,
. The atomic component,
, is reliably provided using the mapped 21 cm radio emission but estimating the molecular hydrogen column density,
, expected for any particular direction, is difficult. The X-ray afterglows of Gamma Ray Bursts (GRBs) are ideal sources to probe X-ray absorption in our Galaxy because they are extragalactic, numerous, bright, have simple spectra and occur randomly across the entire sky. We describe an empirical method, utilizing 493 afterglows detected by the Swift X-ray Telescope, to determine N
Htot through the Milky Way which provides an improved estimate of the X-ray absorption in our Galaxy and thereby leads to more reliable measurements of the intrinsic X-ray absorption and, potentially, other spectral parameters, for extragalactic X-ray sources. We derive a simple function, dependent on the product of the atomic hydrogen column density,
, and dust extinction, E(B − V), which describes the variation of the molecular hydrogen column density,
, of our Galaxy, over the sky. Using the resulting N
Htot we show that the dust-to-hydrogen ratio is correlated with the carbon monoxide emission and use this ratio to estimate the fraction of material which forms interstellar dust grains. Our resulting recipe represents a significant revision in Galactic absorption compared to previous standard methods, particularly at low Galactic latitudes.
Fully printed humidity sensors based on two-dimensional (2D) materials are described. Monolayer graphene oxide (GO) and few-layered black phosphorus (BP) flakes were dispersed in low boiling point ...solvents suitable for inkjet printing. The humidity sensors were fabricated by printing GO and BP sensing layers on printed silver nanoparticle electrodes. The electrical response of the GO and BP sensors to humidity levels ranges from 11 to 97% relative humidity, which revealed a high capacitance sensitivity of 4.45 × 104 times for the GO sensor and 5.08 × 103 times for the BP sensor at 10 Hz operation frequency. Response/recovery times of the GO and BP sensor were found to be 2.7/4.6 s and 4.7/3.0 s respectively. These sensors also showed sensitive and fast response to a proximal human fingertip, showing potential applications in contactless switching.
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