784 research outputs found
Intensification of cattle ranching production systems: Socioeconomic and environmental synergies and risks in Brazil
Intensification of Brazilian cattle ranching systems has attracted both national and international attention due to its direct relation with Amazon deforestation on the one hand and increasing demand of the global population for meat on the other. Since Brazilian cattle ranching is predominantly pasture-based, we particularly focus on pasture management. We summarize the most recurrent opportunities and risks associated with pasture intensification that are brought up within scientific and political dialogues, and discuss them within the Brazilian context. We argue that sustainable intensification of pasturelands in Brazil is a viable way to increase agricultural output while simultaneously sparing land for nature. Since environmental degradation is often associated with low-yield extensive systems in Brazil, it is possible to obtain higher yields, while reversing degradation, by adopting practices like rotational grazing, incorporation of legumes and integrated crop-livestock-forestry systems. Technical assistance is however essential, particularly for small- and medium-scale farmers. Sound complementary policies and good governance must accompany these measures so that a ‘rebound effect’ does not lead to increased deforestation and other adverse social and environmental impacts. It is also important that animal welfare is not compromised. Although the discussion is presented with respect to Brazil, some aspects are relevant to other developing countries
Socioeconomic inequalities in patients undergoing abdominal wall reconstruction in the North-West of England, UK: a three-centre retrospective cohort study
Purpose: Patients from deprived areas are more likely to experience longer waiting times for elective surgery, be multimorbid, and have inferior outcomes from elective and emergency surgery. This study aims to investigate how surgical outcomes vary by deprivation for patients undergoing elective abdominal wall reconstruction. Methods: A three-centre retrospective cohort study was conducted across three hospitals in North-West England, including patients with complex ventral hernias undergoing abdominal wall reconstruction between 2013 and 2021. Demographic data, comorbidities, and index of multiple deprivation quintiles were recorded. Results: 234 patients (49.6% female), age 57 (SD 13) years, underwent elective abdominal wall reconstruction. Significantly higher unemployment rates were found in the most deprived quintiles (Q1 and Q2). There were more smokers in Q1 and Q2, but no significant deprivation related differences in BMI, diabetes, chronic kidney disease or ischaemic heart disease. There were also higher rates of Clavien-Dindo 1–2 complications in Q1 and Q5, but no difference in the Clavien-Dindo 3–4 outcomes. Patients in Q1 and Q5 had a significantly greater hospital length of stay. Conclusion: The association between deprivation and greater unemployment and smoking rates highlights the potential need for equitable support in patient optimisation. The lack of differences in patient co-morbidities and hernia characteristics could represent the application of standardised operative criteria and thresholds. Further research is needed to better understand the relationship between socioeconomic status, complications, and prolonged hospital length of stay
Matrix theory origins of non-geometric fluxes
We explore the origins of non-geometric fluxes within the context of M theory
described as a matrix model. Building upon compactifications of Matrix theory
on non-commutative tori and twisted tori, we formulate the conditions which
describe compactifications with non-geometric fluxes. These turn out to be
related to certain deformations of tori with non-commutative and
non-associative structures on their phase space. Quantization of flux appears
as a natural consequence of the framework and leads to the resolution of
non-associativity at the level of the unitary operators. The quantum-mechanical
nature of the model bestows an important role on the phase space. In
particular, the geometric and non-geometric fluxes exchange their properties
when going from position space to momentum space thus providing a duality among
the two. Moreover, the operations which connect solutions with different fluxes
are described and their relation to T-duality is discussed. Finally, we provide
some insights on the effective gauge theories obtained from these matrix
compactifications.Comment: 1+31 pages, reference list update
Structure in 6D and 4D N=1 supergravity theories from F-theory
We explore some aspects of 4D supergravity theories and F-theory vacua that
are parallel to structures in the space of 6D theories. The spectrum and
topological terms in 4D supergravity theories correspond to topological data of
F-theory geometry, just as in six dimensions. In particular, topological
axion-curvature squared couplings appear in 4D theories; these couplings are
characterized by vectors in the dual to the lattice of axion shift symmetries
associated with string charges. These terms are analogous to the Green-Schwarz
terms of 6D supergravity theories, though in 4D the terms are not generally
linked with anomalies. We outline the correspondence between F-theory topology
and data of the corresponding 4D supergravity theories. The correspondence of
geometry with structure in the low-energy action illuminates topological
aspects of heterotic-F-theory duality in 4D as well as in 6D. The existence of
an F-theory realization also places geometrical constraints on the 4D
supergravity theory in the large-volume limit.Comment: 63 page
Barriers and facilitators to recruitment of physicians and practices for primary care health services research at one centre
<p>Abstract</p> <p>Background</p> <p>While some research has been conducted examining recruitment methods to engage physicians and practices in primary care research, further research is needed on recruitment methodology as it remains a recurrent challenge and plays a crucial role in primary care research. This paper reviews recruitment strategies, common challenges, and innovative practices from five recent primary care health services research studies in Ontario, Canada.</p> <p>Methods</p> <p>We used mixed qualitative and quantitative methods to gather data from investigators and/or project staff from five research teams. Team members were interviewed and asked to fill out a brief survey on recruitment methods, results, and challenges encountered during a recent or ongoing project involving primary care practices or physicians. Data analysis included qualitative analysis of interview notes and descriptive statistics generated for each study.</p> <p>Results</p> <p>Recruitment rates varied markedly across the projects despite similar initial strategies. Common challenges and creative solutions were reported by many of the research teams, including building a sampling frame, developing front-office rapport, adapting recruitment strategies, promoting buy-in and interest in the research question, and training a staff recruiter.</p> <p>Conclusions</p> <p>Investigators must continue to find effective ways of reaching and involving diverse and representative samples of primary care providers and practices by building personal connections with, and buy-in from, potential participants. Flexible recruitment strategies and an understanding of the needs and interests of potential participants may also facilitate recruitment.</p
Selective inhibition of tropomyosin-receptor-kinase A (TrkA) reduces pain and joint damage in two rat models of inflammatory arthritis
Background: Inflammation is an essential component of arthritis pain. Nerve growth factor (NGF) plays a key role in acute and chronic pain states especially those associated with inflammation. NGF acts through tropomyosin-receptor-kinase A (TrkA). NGF blockade has reduced arthritis pain in clinical trials. We explored the mechanisms within the joint which may contribute to the analgesic effects of NGF by selectively inhibiting TrkA in carrageenan-induced or collagen-induced joint pain behaviour. The goal of the current study was to elucidate whether inflammation is central to the efficacy for NGF blockade.
Methods: Rats were injected in their left knees with 2 % carrageenan or saline. Collagen-induced arthritis (CIA) was induced by intradermal injections of a mixture of bovine type II collagen (0.2 mg) and incomplete Freund’s adjuvant (0.2 mg). Oral doses (30 mg/kg) of AR786 or vehicle control were given twice daily after arthritis induction. Ibuprofen-treated (35 mg/kg, orally, once daily) rats with CIA were used as positive analgesic controls. Pain behaviour was measured as hind-limb weight-bearing asymmetry and hind-paw withdrawal thresholds to von Frey hair stimulation (carrageenan synovitis), or withdrawal to joint compression using a Randall Selitto device (CIA). Inflammation was measured as increased knee joint diameter and by histopathological analysis.
Results: Intra-articular injections of carrageenan or induction of CIA was each associated with pain behaviour and synovial inflammation. Systemic administration of the TrkA inhibitor AR786 reduced carrageenan-induced or CIA-induced pain behaviour to control values, and inhibited joint swelling and histological evidence of synovial inflammation and joint damage.
Conclusions: By using two models of varying inflammation we demonstrate for the first time that selective inhibition of TrkA may reduce carrageenan-induced or CIA-induced pain behaviour in rats, in part through potentially inhibiting synovial inflammation, although direct effects on sensory nerves are also likely. Our observations suggest that inflammatory arthritis causes pain and the presence of inflammation is fundamental to the beneficial effects (reduction in pain and pathology) of NGF blockade. Further research should determine whether TrkA inhibition may ameliorate human inflammatory arthritis
Drug problems among homeless individuals in Toronto, Canada: prevalence, drugs of choice, and relation to health status
<p>Abstract</p> <p>Background</p> <p>Drug use is believed to be an important factor contributing to the poor health and increased mortality risk that has been widely observed among homeless individuals. The objective of this study was to determine the prevalence and characteristics of drug use among a representative sample of homeless individuals and to examine the association between drug problems and physical and mental health status.</p> <p>Methods</p> <p>Recruitment of 603 single men, 304 single women, and 284 adults with dependent children occurred at homeless shelters and meal programs in Toronto, Canada. Information was collected on demographic characteristics and patterns of drug use. The Addiction Severity Index was used to assess whether participants suffered from drug problems. Associations of drug problems with physical and mental health status (measured by the SF-12 scale) were examined using regression analyses.</p> <p>Results</p> <p>Forty percent of the study sample had drug problems in the last 30 days. These individuals were more likely to be single men and less educated than those without drug problems. They were also more likely to have become homeless at a younger age (mean 24.8 vs. 30.9 years) and for a longer duration (mean 4.8 vs. 2.9 years). Marijuana and cocaine were the most frequently used drugs in the past two years (40% and 27%, respectively). Drug problems within the last 30 days were associated with significantly poorer mental health status (-4.9 points, 95% CI -6.5 to -3.2) but not with poorer physical health status (-0.03 points, 95% CI -1.3 to 1.3)).</p> <p>Conclusions</p> <p>Drug use is common among homeless individuals in Toronto. Current drug problems are associated with poorer mental health status but not with poorer physical health status.</p
Novel computed tomographic chest metrics to detect pulmonary hypertension
<p>Abstract</p> <p>Background</p> <p>Early diagnosis of pulmonary hypertension (PH) can potentially improve survival and quality of life. Detecting PH using echocardiography is often insensitive in subjects with lung fibrosis or hyperinflation. Right heart catheterization (RHC) for the diagnosis of PH adds risk and expense due to its invasive nature. Pre-defined measurements utilizing computed tomography (CT) of the chest may be an alternative non-invasive method of detecting PH.</p> <p>Methods</p> <p>This study retrospectively reviewed 101 acutely hospitalized inpatients with heterogeneous diagnoses, who consecutively underwent CT chest and RHC during the same admission. Two separate teams, each consisting of a radiologist and pulmonologist, blinded to clinical and RHC data, individually reviewed the chest CT's.</p> <p>Results</p> <p>Multiple regression analyses controlling for age, sex, ascending aortic diameter, body surface area, thoracic diameter and pulmonary wedge pressure showed that a main pulmonary artery (PA) diameter ≥29 mm (odds ratio (OR) = 4.8), right descending PA diameter ≥19 mm (OR = 7.0), true right descending PA diameter ≥ 16 mm (OR = 4.1), true left descending PA diameter ≥ 21 mm (OR = 15.5), right ventricular (RV) free wall ≥ 6 mm (OR = 30.5), RV wall/left ventricular (LV) wall ratio ≥0.32 (OR = 8.8), RV/LV lumen ratio ≥1.28 (OR = 28.8), main PA/ascending aorta ratio ≥0.84 (OR = 6.0) and main PA/descending aorta ratio ≥ 1.29 (OR = 5.7) were significant predictors of PH in this population of hospitalized patients.</p> <p>Conclusion</p> <p>This combination of easily measured CT-based metrics may, upon confirmatory studies, aid in the non-invasive detection of PH and hence in the determination of RHC candidacy in acutely hospitalized patients.</p
Variation in 'fast-track' referrals for suspected cancer by patient characteristic and cancer diagnosis: evidence from 670 000 patients with cancers of 35 different sites.
BACKGROUND: In England, 'fast-track' (also known as 'two-week wait') general practitioner referrals for suspected cancer in symptomatic patients are used to shorten diagnostic intervals and are supported by clinical guidelines. However, the use of the fast-track pathway may vary for different patient groups. METHODS: We examined data from 669 220 patients with 35 cancers diagnosed in 2006-2010 following either fast-track or 'routine' primary-to-secondary care referrals using 'Routes to Diagnosis' data. We estimated the proportion of fast-track referrals by sociodemographic characteristic and cancer site and used logistic regression to estimate respective crude and adjusted odds ratios. We additionally explored whether sociodemographic associations varied by cancer. RESULTS: There were large variations in the odds of fast-track referral by cancer (P<0.001). Patients with testicular and breast cancer were most likely to have been diagnosed after a fast-track referral (adjusted odds ratios 2.73 and 2.35, respectively, using rectal cancer as reference); whereas patients with brain cancer and leukaemias least likely (adjusted odds ratios 0.05 and 0.09, respectively, for brain cancer and acute myeloid leukaemia). There were sex, age and deprivation differences in the odds of fast-track referral (P<0.013) that varied in their size and direction for patients with different cancers (P<0.001). For example, fast-track referrals were least likely in younger women with endometrial cancer and in older men with testicular cancer. CONCLUSIONS: Fast-track referrals are less likely for cancers characterised by nonspecific presenting symptoms and patients belonging to low cancer incidence demographic groups. Interventions beyond clinical guidelines for 'alarm' symptoms are needed to improve diagnostic timeliness
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