38,465 research outputs found
On O(1) contributions to the free energy in Bethe Ansatz systems: the exact g-function
We investigate the sub-leading contributions to the free energy of Bethe
Ansatz solvable (continuum) models with different boundary conditions. We show
that the Thermodynamic Bethe Ansatz approach is capable of providing the O(1)
pieces if both the density of states in rapidity space and the quadratic
fluctuations around the saddle point solution to the TBA are properly taken
into account. In relativistic boundary QFT the O(1) contributions are directly
related to the exact g-function. In this paper we provide an all-orders proof
of the previous results of P. Dorey et al. on the g-function in both massive
and massless models. In addition, we derive a new result for the g-function
which applies to massless theories with arbitrary diagonal scattering in the
bulk.Comment: 28 pages, 2 figures, v2: minor corrections, v3: minor corrections and
references adde
The longitudinal interplay between negative and positive symptom trajectories in patients under antipsychotic treatment: a post hoc analysis of data from a randomized, 1-year pragmatic trial
BACKGROUND: Schizophrenia is a highly heterogeneous disorder with positive and negative symptoms being characteristic manifestations of the disease. While these two symptom domains are usually construed as distinct and orthogonal, little is known about the longitudinal pattern of negative symptoms and their linkage with the positive symptoms. This study assessed the temporal interplay between these two symptom domains and evaluated whether the improvements in these symptoms were inversely correlated or independent with each other. METHODS: This post hoc analysis used data from a multicenter, randomized, open-label, 1-year pragmatic trial of patients with schizophrenia spectrum disorder who were treated with first- and second-generation antipsychotics in the usual clinical settings. Data from all treatment groups were pooled resulting in 399 patients with complete data on both the negative and positive subscale scores from the Positive and Negative Syndrome Scale (PANSS). Individual-based growth mixture modeling combined with interplay matrix was used to identify the latent trajectory patterns in terms of both the negative and positive symptoms. Pearson correlation coefficients were calculated to examine the relationship between the changes of these two symptom domains within each combined trajectory pattern. RESULTS: We identified four distinct negative symptom trajectories and three positive symptom trajectories. The trajectory matrix formed 11 combined trajectory patterns, which evidenced that negative and positive symptom trajectories moved generally in parallel. Correlation coefficients for changes in negative and positive symptom subscale scores were positive and statistically significant (P < 0.05). Overall, the combined trajectories indicated three major distinct patterns: (1) dramatic and sustained early improvement in both negative and positive symptoms (n = 70, 18%), (2) mild and sustained improvement in negative and positive symptoms (n = 237, 59%), and (3) no improvement in either negative or positive symptoms (n = 82, 21%). CONCLUSIONS: This study of symptom trajectories over 1 year shows that changes in negative and positive symptoms were neither inversely nor independently related with each other. The positive association between these two symptom domains supports the notion that different symptom domains in schizophrenia may depend on each other through a unified upstream pathological disease process
Fermion masses in the economical 3-3-1 model
We show that, in frameworks of the economical 3-3-1 model, all fermions get
masses. At the tree level, one up-quark and two down-quarks are massless, but
the one-loop corrections give all quarks the consistent masses. This conclusion
is in contradiction to the previous analysis in which, the third scalar triplet
has been introduced. This result is based on the key properties of the model:
First, there are three quite different scales of vacuum expectation values:
\om \sim {\cal O}(1) \mathrm{TeV}, v \approx 246 \mathrm{GeV} and . Second, there exist two types of Yukawa couplings
with different strengths: the lepton-number conserving couplings 's and the
lepton-number violating ones 's satisfying the condition in which the second
are much smaller than the first ones: .
With the acceptable set of parameters, numerical evaluation shows that in
this model, masses of the exotic quarks also have different scales, namely, the
exotic quark () gains mass GeV, while the
D_\al exotic quarks (q_{D_\al} = -1/3) have masses in the TeV scale:
m_{D_\al} \in 10 \div 80 TeV.Comment: 20 pages, 8 figure
Sigmoid Volvulus and Ileosigmoid Knotting at St. Mary’s Hospital Lacor in Gulu, Uganda
Background: Sigmoid volvulus is a common cause of intestinal obstruction in developing countries where it affects relatively young people. Little is known about this condition in our country and there is yet no literature from an environment like ours (northern Uganda) where civil war has devastated the economy with most of the populace displaced into internally displaced peoples’ camp. The main objective of this study was to determine the demographics, treatment and outcome of sigmoid Volvulus cases seen at Lacor Hospital.Methods: This was both a retrospective and prospective study of patients who presented with sigmoid volvulus at St. Mary’s Hospital Lacor over a period of 61/2 years from 1st January 2002 to 31st July 2008. Medical records of patients who underwent sigmoid surgery was stratified for the following measures; demographic characteristics, presentation to hospital (emergency or elective), operative finding and operative procedure, complication, co-ominous factors and outcome. Similar data was gathered from patients who were prospectively followed up. Data was analyzed using SPSS.Results: A total of 44 patients were studied. Their age ranged from 16 to 80 years with a mean of 52.2years (SD +/- 15.98) and a mode of 60years. There was a preponderance of male (84%) with a male to female sex ratio of 5.3: 1. The disease significantly affected the older males compared with females P=0.032. Approximately 77% of the patients presented acutely and had to undergo emergency surgical intervention, the rest were subacute. About 75% of the patients were treated with primary resection and anastomosis, of which 52.2% were emergency cases. Colostomy was offered to 20.5% and sigmoidoscopic derotation to 4.5%. Overall mortality rate was 15.9% and of the patients who died, 18% had primary resection and anastomosis, while 11% were offered colostomy, (P>0.05). Most of those who died were either the older ones (median age 68years) and/or had co morbid illness such as diabetes mellitus, hypertension, intra-abdominal abscess and cancer.Conclusion: Sigmoid volvulus is relatively rare in our community. It commonly affect males particularly the old. Most of the patients presented acutely, requiring immediate resuscitation and surgical approach. In viable bowel, primary resection and anastomosis of the twisted sigmoid is feasible as it may not adversely affect outcome. Nevertheless colostomy should be considered if the bowel is gangrenous or perforated. Though the disease carries a high mortality, most of the patient who die are either older and/or have co-morbid conditions
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Quasi-diffusion magnetic resonance imaging (QDI): A fast, high b-value diffusion imaging technique.
To enable application of non-Gaussian diffusion magnetic resonance imaging (dMRI) techniques in large-scale clinical trials and facilitate translation to clinical practice there is a requirement for fast, high contrast, techniques that are sensitive to changes in tissue structure which provide diagnostic signatures at the early stages of disease. Here we describe a new way to compress the acquisition of multi-shell b-value diffusion data, Quasi-Diffusion MRI (QDI), which provides a probe of subvoxel tissue complexity using short acquisition times (1-4 min). We also describe a coherent framework for multi-directional diffusion gradient acquisition and data processing that allows computation of rotationally invariant quasi-diffusion tensor imaging (QDTI) maps. QDI is a quantitative technique that is based on a special case of the Continuous Time Random Walk model of diffusion dynamics and assumes the presence of non-Gaussian diffusion properties within tissue microstructure. QDI parameterises the diffusion signal attenuation according to the rate of decay (i.e. diffusion coefficient, D in mm2 s-1) and the shape of the power law tail (i.e. the fractional exponent, α). QDI provides analogous tissue contrast to Diffusional Kurtosis Imaging (DKI) by calculation of normalised entropy of the parameterised diffusion signal decay curve, Hn, but does so without the limitations of a maximum b-value. We show that QDI generates images with superior tissue contrast to conventional diffusion imaging within clinically acceptable acquisition times of between 84 and 228 s. We show that QDI provides clinically meaningful images in cerebral small vessel disease and brain tumour case studies. Our initial findings suggest that QDI may be added to routine conventional dMRI acquisitions allowing simple application in clinical trials and translation to the clinical arena
Buprenorphine added on brief cognitive behavioral therapy for treatment of methamphetamine use disorder
Background: Methamphetamine (MA) use remains a major public health concern around the world. Recent findings suggest that buprenorphine may be helpful for cocaine use reduction. Moreover, animal studies described reduced dopamine peak effect following MA use, due to the administration of low dose buprenorphine.
Objectives: This study examined the effectiveness of buprenorphine with brief cognitive behavioral therapy on MA use disorder.
Methods: The study was conducted in an outpatient substance abuse treatment center in Qazvin, Iran. Nineteen MA users received buprenorphine for 24 weeks combined with brief cognitive behavioral therapy in an outpatient substance abuse treatment program, three times per week, as a before and after non - randomization study. Clinical outcomes included treatment retention, MA use, degree of MA dependency and craving, quality of life, cognitive abilities questionnaire, addiction severity and also adverse events. Data was analyzed by performing repeated measures analysis and the Friedman test for nonparametric variables.
Results: Fifteen participants completed the study during six months and frequency of MA use was significantly decreased at 24 weeks (P < 0.001). There were also significant reductions in craving (P < 0.001), degree of MA dependence (P < 0.001), and improvements in quality of life, cognitive ability, and some subscales of addiction severity.
Conclusions: The results of this preliminary clinical study demonstrated that buprenorphine could potentially attenuate MA craving and alternate rewarding effects of MA and had promising effects on cognitive impairment. Furthermore, buprenorphine can be considered as a harm reduction intervention in some communities, in which the people, as a result of cultural beliefs, do not accept a therapy, which only consists of counseling and no medications
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