1,923 research outputs found
Pilot Study Results from a Brief Intervention to Create Smoke-Free Homes
Very few community-based intervention studies have examined how to effectively increase the adoption of smoke-free homes. A pilot study was conducted to test the feasibility, acceptability, and short-term outcomes of a brief, four-component intervention for promoting smoke-free home policies among low-income households. We recruited forty participants (20 smokers and 20 nonsmokers) to receive the intervention at two-week intervals. The design was a pretest-posttest with follow-up at two weeks after intervention. The primary outcome measure was self-reported presence of a total home smoking ban. At follow-up, 78% of participants reported having tried to establish a smoke-free rule in their home, with significantly more nonsmokers attempting a smoke-free home than smokers (P = .03). These attempts led to increased smoking restrictions, that is, going from no ban to a partial or total ban, or from a partial to a total ban, in 43% of the homes. At follow-up, 33% of the participants reported having made their home totally smoke-free. Additionally, smokers reported smoking fewer cigarettes per day. Results suggest that the intervention is promising and warrants a rigorous efficacy trial
Data-driven efficient score tests for deconvolution problems
We consider testing statistical hypotheses about densities of signals in
deconvolution models. A new approach to this problem is proposed. We
constructed score tests for the deconvolution with the known noise density and
efficient score tests for the case of unknown density. The tests are
incorporated with model selection rules to choose reasonable model dimensions
automatically by the data. Consistency of the tests is proved
Risk factors for behavior problems in cats presented to an Australian companion animal behavior clinic
Behavior problems in companion animals are common reasons for relinquishment or euthanasia. Insight into the risk factors for problem behaviors will facilitate the construction of strategies for solutions. We identified risk factors for behavior problems in domestic cats whose owners contacted a companion animal behavior clinic in Brisbane, Australia. Owners of 1,556 cats reported on their cats' behavior problem, breed, sex and age, and owner's postcodes and work routine were also recorded. Risk factors were determined from proportional morbidities for the behavior problem that each cat was reported as having. Breed effects were also assessed by comparing the numbers of cats in each breed group with the breeds of registered cats in a part of the catchment area. Behavior problems in domestic cats where the owners sought professional advice were mostly (71% of all cats) related to house soiling, usually urination, and aggression, especially to familiar people. Persian and similar breeds were at reduced risk of aggression to familiar cats but increased risk of house soiling, compared to other breed groups. Overall, Persian, Siamese, Burmese, and similar breeds had more behavior problems than companion cat breeds. Older cats showed increasing tolerance of familiar people but reduced tolerance of other cats. Males were more likely to present with excessive vocalization and house soiling with urine and less likely to present with aggression between familiar cats. We conclude that cat breed, age and sex, and social advantage of the area in which the cat lives are risk factors for specific behavior problems
Tools to overcome potential barriers to chlamydia screening in general practice: Qualitative evaluation of the implementation of a complex intervention
Background:
Chlamydia trachomatis remains a significant public health problem. We used a complex intervention, with general practice staff, consisting of practice based workshops, posters, computer prompts and testing feedback and feedback to increase routine chlamydia screening tests in under 25 year olds in South West England. We aimed to evaluate how intervention components were received by staff and to understand what determined their implementation into ongoing practice.
Methods:
We used face-to-face and telephone individual interviews with 29 general practice staff analysed thematically within a Normalisation Process Theory Framework which explores: 1. Coherence (if participants understand the purpose of the intervention); 2. Cognitive participation (engagement with and implementation of the intervention); 3. Collective action (work actually undertaken that drives the intervention forwards); 4. Reflexive monitoring (assessment of the impact of the intervention).
Results:
Our results showed coherence as all staff including receptionists understood the purpose of the training was to make them aware of the value of chlamydia screening tests and how to increase this in their general practice. The training was described by nearly all staff as being of high quality and responsible for creating a shared understanding between staff of how to undertake routine chlamydia screening.
Cognitive participation in many general practice staff teams was demonstrated through their engagement by meeting after the training to discuss implementation, which confirmed the role of each staff member and the use of materials. However several participants still felt unable to discuss chlamydia in many consultations or described sexual health as low priority among colleagues. National targets were considered so high for some general practice staff that they didnât engage with the screening intervention.
Collective action work undertaken to drive the intervention included use of computer prompts which helped staff remember to make the offer, testing rate feedback and having a designated lead. Ensuring patients collected samples when still in the general practice was not attained in most general practices.
Reflexive monitoring showed positive feedback from patients and other staff about the value of screening, and feedback about the general practices testing rates helped sustain activity.
Conclusions:
A complex intervention including interactive workshops, materials to help implementation and feedback can help chlamydia screening testing increase in general practices
Quantum Monte Carlo treatment of elastic exciton-exciton scattering
We calculate cross sections for low energy elastic exciton-exciton scattering
within the effective mass approximation. Unlike previous theoretical
approaches, we give a complete, non-perturbative treatment of the four-particle
scattering problem. Diffusion Monte Carlo is used to calculate the essentially
exact energies of scattering states, from which phase shifts are determined.
For the case of equal-mass electrons and holes, which is equivalent to
positronium-positronium scattering, we find a_s = 2.1 a_x for scattering of
singlet-excitons and a_s= 1.5 a_x for triplet-excitons, where a_x is the
excitonic radius. The spin dependence of the cross sections arises from the
spatial exchange symmetry of the scattering wavefunctions. A significant
triplet-triplet to singlet-singlet scattering process is found, which is
similar to reported effects in recent experiments and theory for excitons in
quantum wells. We also show that the scattering length can change sign and
diverge for some values of the mass ratio m_h/m_e, an effect not seen in
previous perturbative treatments.Comment: 6 pages, 6 figures. Revision has updated figures, improved paper
structure, some minor correction
An epidemiological analysis of dog behavior problems presented to an Australian behavior clinic, with associated risk factors
Records of dogs presented to a behavior clinic servicing the eastern seaboard of Australia in and around Brisbane and the Gold Coast were analyzed for principal behavior problems and the related factors, from information recorded at the time that the owner approached the clinic for assistance. Data relating to 7,858 dogs presenting with 11,521 behavior problems between 2001 and 2013 were analyzed. Twenty-two principal behavior problems were identified, of which the most common, in declining order, were aggression toward people, barking, and anxious behavior. Male dogs were at greater risk of several behavior problems, compared to female dogs. Low socioeconomic status of owners and a short period spent at home each week were also associated with a greater risk of several behavior problems. The prevalence of breeds and breed groups presented to the clinic were compared with dog registrations at the local city council, and there were more working dogs; hounds and utility dogs; and fewer terriers, toy dogs, and nonsporting dogs in the clinic population. Uncommon breeds were overrepresented in the clinic population compared to local registrations. The risk of developing behavior problems is discussed in the light of evidence about the dogs and their owners
Accelerating growth of HFC-227ea (1,1,1,2,3,3,3-heptafluoropropane) in the atmosphere
We report the first measurements of 1,1,1,2,3,3,3-heptafluoropropane (HFC-227ea), a substitute for ozone depleting compounds, in air samples originating from remote regions of the atmosphere and present evidence for its accelerating growth. Observed mixing ratios ranged from below 0.01 ppt in deep firn air to 0.59 ppt in the current northern mid-latitudinal upper troposphere. Firn air samples collected in Greenland were used to reconstruct a history of atmospheric abundance. Year-on-year increases were deduced, with acceleration in the growth rate from 0.029 ppt per year in 2000 to 0.056 ppt per year in 2007. Upper tropospheric air samples provide evidence for a continuing growth until late 2009. Furthermore we calculated a stratospheric lifetime of 370 years from measurements of air samples collected on board high altitude aircraft and balloons. Emission estimates were determined from the reconstructed atmospheric trend and suggest that current "bottom-up" estimates of global emissions for 2005 are too high by a factor of three
Maximum likelihood drift estimation for a threshold diffusion
We study the maximum likelihood estimator of the drift parameters of a
stochastic differential equation, with both drift and diffusion coefficients
constant on the positive and negative axis, yet discontinuous at zero. This
threshold diffusion is called drifted Oscillating Brownian motion.For this
continuously observed diffusion, the maximum likelihood estimator coincide with
a quasi-likelihood estimator with constant diffusion term. We show that this
estimator is the limit, as observations become dense in time, of the
(quasi)-maximum likelihood estimator based on discrete observations. In long
time, the asymptotic behaviors of the positive and negative occupation times
rule the ones of the estimators. Differently from most known results in the
literature, we do not restrict ourselves to the ergodic framework: indeed,
depending on the signs of the drift, the process may be ergodic, transient or
null recurrent. For each regime, we establish whether or not the estimators are
consistent; if they are, we prove the convergence in long time of the properly
rescaled difference of the estimators towards a normal or mixed normal
distribution. These theoretical results are backed by numerical simulations
Structurally Complex Osteosarcoma Genomes Exhibit Limited Heterogeneity within Individual Tumors and across Evolutionary Time
Osteosarcoma is an aggressive malignancy characterized by high genomic complexity. Identification of few recurrent mutations in protein coding genes suggests that somatic copy-number aberrations (SCNA) are the genetic drivers of disease. Models around genomic instability conflict-it is unclear whether osteosarcomas result from pervasive ongoing clonal evolution with continuous optimization of the fitness landscape or an early catastrophic event followed by stable maintenance of an abnormal genome. We address this question by investigating SCNAs in >12,000 tumor cells obtained from human osteosarcomas using single-cell DNA sequencing, with a degree of precision and accuracy not possible when inferring single-cell states using bulk sequencing. Using the CHISEL algorithm, we inferred allele- and haplotype-specific SCNAs from this whole-genome single-cell DNA sequencing data. Surprisingly, despite extensive structural complexity, these tumors exhibit a high degree of cell-cell homogeneity with little subclonal diversification. Longitudinal analysis of patient samples obtained at distant therapeutic timepoints (diagnosis, relapse) demonstrated remarkable conservation of SCNA profiles over tumor evolution. Phylogenetic analysis suggests that the majority of SCNAs were acquired early in the oncogenic process, with relatively few structure-altering events arising in response to therapy or during adaptation to growth in metastatic tissues. These data further support the emerging hypothesis that early catastrophic events, rather than sustained genomic instability, give rise to structural complexity, which is then preserved over long periods of tumor developmental time. SIGNIFICANCE: Chromosomally complex tumors are often described as genomically unstable. However, determining whether complexity arises from remote time-limited events that give rise to structural alterations or a progressive accumulation of structural events in persistently unstable tumors has implications for diagnosis, biomarker assessment, mechanisms of treatment resistance, and represents a conceptual advance in our understanding of intratumoral heterogeneity and tumor evolution
Draft Genome Sequence of the Human-Pathogenic Fungus Scedosporium boydii
The opportunistic fungal pathogen Scedosporium boydii is the most common Scedosporium species in French patients with cystic fibrosis. Here we present the first genome report for S. boydii, providing a resource which may enable the elucidation of the pathogenic mechanisms in this species
- âŠ