Perturbation bounds for constrained and weighted least squares problems

AbstractWe derive perturbation bounds for the constrained and weighted linear least squares (LS) problems. Both the full rank and rank-deficient cases are considered. The analysis generalizes some results of earlier works

Simulations of quantum dynamics with fermionic phase-space representations using numerical matrix factorizations as stochastic gauges

The Gaussian phase-space representation can be used to implement quantum dynamics for fermionic particles numerically. To improve numerical results, we explore the use of dynamical diffusion gauges in such implementations. This is achieved by benchmarking quantum dynamics of few-body systems against independent exact solutions. A diffusion gauge is implemented here as a so-called noise-matrix, which satisfies a matrix equation defined by the corresponding Fokker--Planck equation of the phase-space representation. For the physical systems with fermionic particles considered here, the numerical evaluation of the new diffusion gauges allows us to double the practical simulation time, compared with hitherto known analytic noise-matrices. This development may have far reaching consequences for future quantum dynamical simulations of many-body systems

Mast Cell Survival and Mediator Secretion in Response to Hypoxia

Tissue hypoxia is a consequence of decreased oxygen levels in different inflammatory conditions, many associated with mast cell activation. However, the effect of hypoxia on mast cell functions is not well established. Here, we have investigated the effect of hypoxia per se on human mast cell survival, mediator secretion, and reactivity. Human cord blood derived mast cells were subjected to three different culturing conditions: culture and stimulation in normoxia (21% O2); culture and stimulation in hypoxia (1% O2); or 24 hour culture in hypoxia followed by stimulation in normoxia. Hypoxia, per se, did not induce mast cell degranulation, but we observed an increased secretion of IL-6, where autocrine produced IL-6 promoted mast cell survival. Hypoxia did not have any effect on A23187 induced degranulation or secretion of cytokines. In contrast, cytokine secretion after LPS or CD30 treatment was attenuated, but not inhibited, in hypoxia compared to normoxia. Our data suggests that mast cell survival, degranulation and cytokine release are sustained under hypoxia. This may be of importance for host defence where mast cells in a hypoxic tissue can react to intruders, but also in chronic inflammations where mast cell reactivity is not inhibited by the inflammatory associated hypoxia

General symptom reporting in female fibromyalgia patients and referents: a population-based case-referent study

<p>Abstract</p> <p>Background</p> <p>Fibromyalgia is characterized by widespread musculoskeletal pain and palpation tenderness. In addition to these classic symptoms, fibromyalgia patients tend to report a number of other complaints. What these other complaints are and how often they are reported as compared with related referents from the general population is not very well known. We therefore hypothesized that subjects with fibromyalgia report more of a wide range of symptoms as compared with referents of the same sex and age from the general population.</p> <p>Methods</p> <p>138 women with diagnosed fibromyalgia in primary health care and 401 referents from the general population matched to the cases by sex, age and residential area responded to a postal questionnaire where information on marital status, education, occupational status, income level, immigrant status, smoking habits physical activity, height and weight history and the prevalence of 42 defined symptoms was sought.</p> <p>Results</p> <p>The cases had lower educational and income levels, were more often unemployed, on sick leave or on disability pension and were more often first generation immigrants than the referents. They were also heavier, shorter and more often had a history of excessive food intake and excessive weight loss. When these differences were taken into account, cases reported not only significantly more presumed fibromyalgia symptoms but also significantly more of general symptoms than the referents. The distribution of symptoms was similar in subjects with fibromyalgia and referents, indicating a generally higher symptom reporting level among the former.</p> <p>Conclusion</p> <p>Subjects with fibromyalgia had a high prevalence of reported general symptoms than referents. Some of these differences may be a consequence of the disorder while others may reflect etiological processes.</p

Psychosocial factors during the first year after a coronary heart disease event in cases and referents. Secondary Prevention in Uppsala Primary Health Care Project (SUPRIM)

<p>Abstract</p> <p>Background</p> <p>A large number of studies have reported on the psychosocial risk factor pattern prior to coronary heart disease events, but few have investigated the situation during the first year after an event, and none has been controlled. We therefore performed a case-referent study in which the prevalence of a number of psychosocial factors was evaluated.</p> <p>Methods</p> <p>Three hundred and forty-six coronary heart disease male and female cases no more than 75 years of age, discharged from hospital within the past 12 months, and 1038 referents from the general population, matched to the cases by age, sex and place of living, received a postal questionnaire in which information on lifestyle, psychosocial and quality of life measures were sought.</p> <p>Results</p> <p>The cases were, as expected, on sick leave to a larger extent than the referents, reported poorer fitness, poorer perceived health, fewer leisure time activities, but unexpectedly reported better social support, and more optimistic views of the future than the referents. There were no significant case-referent differences in everyday life stress, stressful life events, vital exhaustion, depressive mood, coping or life orientation test. However, women reported less favourable situations than men regarding stressful life events affecting others, vital exhaustion, depressive mood, coping, self-esteem, sleep, and symptom reporting, and female cases reported the most unfavourable situation of all groups.</p> <p>Conclusion</p> <p>In this first controlled study of the situation during the first year after a CHD event disease and gender status both appeared to be determinants of psychological well-being, with gender status apparently the strongest. This may have implications for cardiac rehabilitation programmes.</p

Pre-surgical depression and anxiety and recovery following coronary artery bypass graft surgery

We aimed to explore the combined contribution of pre-surgical depression and anxiety symptoms for recovery following coronary artery bypass graft (CABG) using data from 251 participants. Participants were assessed prior to surgery for depression and anxiety symptoms and followed up at 12 months to assess pain and physical symptoms, while hospital emergency admissions and death/major adverse cardiac events (MACE) were monitored on average 2.68 years after CABG. After controlling for covariates, baseline anxiety symptoms, but not depression, were associated with greater pain (β = 0.231, p = 0.014) and greater physical symptoms (β = 0.194, p = 0.034) 12 months after surgery. On the other hand, after controlling for covariates, baseline depression symptoms, but not anxiety, were associated with greater odds of having an emergency admission (OR 1.088, CI 1.010–1.171, p = 0.027) and greater hazard of death/MACE (HR 1.137, CI 1.042–1.240, p = 0.004). These findings point to different pathways linking mood symptoms with recovery after CABG surgery