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We present a method for automatic inference of conditions on the initial states of a program that guarantee that the safety assertions in the program are not violated. Constrained Horn clauses (CHCs) are used to model the program and assertions in a uniform way, and we use standard abstract interpretations to derive an over-approximation of the set of unsafe initial states. The precondition then is the constraint corresponding to the complement of that set, under-approximating the set of safe initial states. This idea of complementation is not new, but previous attempts to exploit it have suffered from the loss of precision. Here we develop an iterative specialisation algorithm to give more precise, and in some cases optimal safety conditions. The algorithm combines existing transformations, namely constraint specialisation, partial evaluation and a trace elimination transformation. The last two of these transformations perform polyvariant specialisation, leading to disjunctive constraints which improve precision. The algorithm is implemented and tested on a benchmark suite of programs from the literature in precondition inference and software verification competitions.
Testosterone influences well-being, mood and cognition and may play a role in the pathophysiology of bipolar disorder.
To examine testosterone levels in patients with bipolar disorder compared with healthy controls.
We examined baseline total testosterone levels and current depression scores in male and female patients with bipolar disorder and mild to moderate depression and healthy controls.
A significant interaction between diagnosis and gender was observed (F(2,97)=9.791, P=0.002). Testosterone levels were significantly lower for male patients with bipolar disorder compared with male controls (P=0.001). Women with bipolar disorder had significantly higher testosterone levels than female controls (P=0.03).
Disturbances in testosterone levels may represent an important neurobiological abnormality in bipolar disorder and may differ by gender. If these findings are confirmed, the use of gender appropriate treatment strategies for the normalisation of testosterone levels in bipolar disorder depression should be further explored.
Previous studies of facial emotion processing in bipolar disorder (BD) have reported conflicting findings. In independently conducted studies, we investigate facial emotion labeling in euthymic and depressed BD patients using tasks with static and dynamically morphed images of different emotions displayed at different intensities. Study 1 included 38 euthymic BD patients and 28 controls. Participants completed two tasks: labeling of static images of basic facial emotions (anger, disgust, fear, happy, sad) shown at different expression intensities; the Eyes Test (Baron-Cohen, Wheelwright, Hill, Raste, & Plumb, 2001), which involves recognition of complex emotions using only the eye region of the face. Study 2 included 53 depressed BD patients and 47 controls. Participants completed two tasks: labeling of “dynamic” facial expressions of the same five basic emotions; the Emotional Hexagon test (Young, Perret, Calder, Sprengelmeyer, & Ekman, 2002). There were no significant group differences on any measures of emotion perception/labeling, compared to controls. A significant group by intensity interaction was observed in both emotion labeling tasks (euthymia and depression), although this effect did not survive the addition of measures of executive function/psychomotor speed as covariates. Only 2.6–15.8% of euthymic patients and 7.8–13.7% of depressed patients scored below the 10th percentile of the controls for total emotion recognition accuracy. There was no evidence of specific deficits in facial emotion labeling in euthymic or depressed BD patients. Methodological variations—including mood state, sample size, and the cognitive demands of the tasks—may contribute significantly to the variability in findings between studies. (JINS, 2015, 21, 709–721)
Adequate Zn and Mg intakes may be beneficial for the prevention and treatment of mental health problems, such as depression, anxiety and attention-deficit hyperactivity disorder. We aimed to investigate the prospective association between dietary intakes of Zn and Mg and internalising and externalising behaviour problems in a population-based cohort of adolescents.
Prospective analysis (general linear mixed models) of dietary intakes of Zn and Mg assessed using a validated FFQ and mental health symptoms assessed using the Youth Self-Report (YSR), adjusting for sex, physical activity, family income, supplement status, dietary misreporting, BMI, family functioning and energy intake.
Western Australian Pregnancy Cohort (Raine) Study.
Adolescents (n 684) at the 14- and 17-year follow-ups.
Higher dietary intake of Mg (per sd increase) was significantly associated with reduced externalising behaviours (β=−1·45; 95 % CI −2·40, −0·50; P=0·003). There was a trend towards reduced externalising behaviours with higher Zn intake (per sd increase; β=−0·73; 95 % CI −1·57, 0·10; P=0·085).
The study shows an association between higher dietary Mg intake and reduced externalising behaviour problems in adolescents. We observed a similar trend, although not statistically significant, for Zn intake. Randomised controlled trials are necessary to determine any benefit of micronutrient supplementation in the prevention and treatment of mental health problems in adolescents.
To describe the role, contribution and value of research nurses in New Zealand community-based or primary health care research.
Research nurses are increasingly recognised as having a key role in undertaking successful research in hospitals and clinical trial units however only limited work has been undertaken to examine their role in community-based research. Undertaking health research in the community has unique challenges particularly in relation to research design and recruitment and retention of participants.
We describe four community-based research projects involving research nurses, each with particular recruitment, retention and logistical problems. Vignettes are used to illustrate the role, contribution and value of research nurses in a diverse range of community research projects.
The knowledge and skills used by research nurses in these projects included familiarity with communities, cultural competence, health care systems and practice philosophies and in particular with vulnerable populations. Their research actions and activities include competence with a broad range of research methodologies, organisational efficiency, family-centred approach, along with advocacy and flexibility. These are underpinned by nursing knowledge and clinical expertise contributing to an ability to work autonomously. These four projects demonstrate that research nurses in community-based research possess specific attributes which facilitate successful study development, implementation and outcome.
White matter (WM) change plays an important role in age-related cognitive decline. In this review, we consider methodological advances with particular relevance to the role of WM in age-related changes in processing speed. In this context, intra-individual variability in processing speed performance has emerged as a sensitive proxy of cognitive and neurological decline while neuroimaging techniques used to assess WM change have become increasingly more sensitive. Together with a carefully designed task protocol, we emphasize that the combined implementation of intra-individual variability and neuroimaging techniques hold promise for specifying the WM-processing speed relationship with implications for normative and clinical samples. (JINS, 2014, 20, 1–6)
Alzheimer's disease (AD) is considered to be a disorder predominantly affecting memory. It is increasingly recognized that the cognitive profile may be heterogeneous. We hypothesized that it would be possible to define distinct “cognitive phenotypes” in older people with AD.
Participants from three individual studies were included, consisting of 109 patients with a diagnosis of probable AD, and 91 age- and gender-matched control participants. All had demographic and cognitive assessment data available, including the Cambridge Cognitive Examination of the Elderly (CAMCOG). The CAMCOG scores and sub-scores were further analyzed using hierarchical cluster analysis and factor analysis.
Three clusters were identified. The scores loaded onto three factors representing the domains of attention, praxis, calculation, and perception; memory; and language comprehension and executive function. The main difference between the clusters related to degree of memory impairment. The composite score for memory between the clusters remained significantly different despite adjustment for illness duration and age of onset (p < 0.001).
These data suggest clinical heterogeneity within an older group of people with AD. This may have implications for diagnosis, prognosis, response to currently available treatments, and the development of novel therapies.
Using unique daily fund-manager trade data, we examine the role of institutional trading in influencing firm performance. We show that short-horizon informed trading by multiple institutional investors effectively disciplines corporate management. Our focus is on short-term “swing” trades, sequences with three phases (e.g., buy-sell-buy). We find swing trades increase stock price informativeness, are profitable after costs, and improve market efficiency. This increase in stock price informativeness is associated with subsequent firm outperformance. Trades are most beneficial with optimal stock holdings that reflect the information acquisition incentives of investors as well as liquidity costs.
The ability to safely and effectively manage the airway is among the most fundamental and challenging aspects of out-of-hospital (OOH) emergency medical treatment. Commonly used devices to facilitate OOH airway management encompass a spectrum from basic means, such as the bag-valve mask (BVM), to more advanced and invasive means, such as the esophageal-tracheal combitube, laryngeal mask airway (LMA), laryngeal tube airway (LT), endotracheal tube (ET), and, ultimately, emergency surgical airways. End-tidal carbon dioxide (PetCO2) monitoring has emerged as the technology that can best confirm endotracheal or endobronchial location of an endotracheal tube. The threshold for detection of exhaled CO2 is significantly lower for capnometry and capnography as opposed to colorimetric devices. The use of capnography for OOH airway management enhances patient safety and can prevent the problem of unrecognized misplaced intubation (UMI) and should be a mandatory component of OOH airway management.
Single crystal-silicon quantum well layers with SiO2 barriers were grown from silicon-on-insulator substrates. Photoluminescence in the red and near-infrared was observed for average layer thickness < 8 nm, with peak signal for 2-nm thickness. The luminescence spectrum was essentially independent of well width for SiO2 barriers, but the photoluminescence intensity decreased sharply after annealing in Ar. These results suggest the importance of radiation from surface states. In contrast to oxide-passivated silicon nanocrystals and to porous silicon, the room-temperature photoluminescence quantum efficiency is low (10-4-10-5), probably due to variations in layer thickness and to diffusion of photoexcited carriers to fast nonradiative recombination centers.
Abnormal diffusion parameters are reported in specific brain regions and white matter tracts in bipolar disorder.
To investigate whether these abnormalities are generalised, and thus evident in large regions of white matter.
Diffusion parameters were measured at several regions in the corpus callosum and in deep/periventricular white matter in 28 currently euthymic patients with bipolar disorder and controls. White matter hyperintensity loads were assessed.
Comparing the whole data-sets using the sign test, in the group with bipolar disorder, mean diffusivity was greater at all 15 sites (P<0.001) and fractional anisotropy was reduced at 13 (P<0.01). The effect of diagnosis was significant for callosal mean diffusivity and fractional anisotropy and for deep/periventricular mean diffusivity (MANCOVA). Comparing individual regions (Mann–Whitney U-test), prefrontal and periventricular mean diffusivity were significantly increased; callosal and occipital fractional anisotropy were significantly reduced. Former substance use and lithium were possible confounding factors. Periventricular white matter hyperintensities were associated with significantly increased periventricular mean diffusivity in individuals with bipolar disorder.
Generalised white matter microstructural abnormalities may exist in bipolar disorder, possibly exacerbated by past substance use and ameliorated by lithium.