967 research outputs found
Doubly perturbed neutrinos and the mixing parameter
We further study a predictive model for the masses and mixing matrix of three
Majorana neutrinos. At zeroth order the model yielded degenerate neutrinos and
a generalized ``tribimaximal" mixing matrix. At first order the mass
splitting was incorporated and the tribimaximal mixing matrix emerged with
very small corrections but with a zero value for the parameter . In the
present paper a different, assumed weaker, perturbation is included which gives
a non zero value for and further corrections to other quantities.
These corrections are worked out and their consequences discussed under the
simplifying assumption that the conventional CP violation phase vanishes. It is
shown that the existing measurements of the parameter provide strong
bounds on in this model.Comment: 8 page
Semi-leptonic (1968) decays as a scalar meson probe
The unusual multiplet structures associated with the light spin zero mesons
have recently attracted a good deal of theoretical attention. Here we discuss
some aspects associated with the possibility of getting new experimental
information on this topic from semi-leptonic decays of heavy charged mesons
into an isosinglet scalar or pseudoscalar plus leptons.Comment: 11 pages, 4 figure
Electrical transport and optical studies of ferromagnetic Cobalt doped ZnO nanoparticles exhibiting a metal-insulator transition
The observed correlation of oxygen vacancies and room temperature
ferromagnetic ordering in Co doped ZnO1-o nanoparticles reported earlier (Naeem
et al Nanotechnology 17, 2675-2680) has been further explored by transport and
optical measurements. In these particles room temperature ferromagnetic
ordering had been observed to occur only after annealing in forming gas. In the
current work the optical properties have been studied by diffuse reflection
spectroscopy in the UV-Vis region and the band gap of the Co doped compositions
has been found to decrease with Co addition. Reflections minima are observed at
the energies characteristic of Co+2 d-d (tethrahedral symmetry) crystal field
transitions, further establishing the presence of Co in substitutional sites.
Electrical transport measurements on palletized samples of the nanoparticles
show that the effect of a forming gas is to strongly decrease the resistivity
with increasing Co concentration. For the air annealed and non-ferromagnetic
samples the variation in the resistivity as a function of Co content are
opposite to those observed in the particles prepared in forming gas. The
ferromagnetic samples exhibit an apparent change from insulator to metal with
increasing temperatures for T>380K and this change becomes more pronounced with
increasing Co content. The magnetic and resistive behaviors are correlated by
considering the model by Calderon et al [M. J. Calderon and S. D. Sarma, Annals
of Physics 2007 (Accepted doi: 10.1016/j.aop.2007.01.010] where the
ferromagnetism changes from being mediated by polarons in the low temperature
insulating region to being mediated by the carriers released from the weakly
bound states in the higher temperature metallic region.Comment: 7 pages, 6 figure
Maximizing the economic benefits of a grid-tied microgrid using solar-wind complementarity
The increasing use of intermittent, renewable energy sources (RESs) for electricity generation in microgrids (MGs) requires efficient strategies for reliable and economic operation. Complementarity between RESs provides good prospects for integrating several local energy sources and reducing the costs of MG setup and operations. This paper presents a framework for maximizing the economic benefits of a grid-tied MG by exploiting the spatial and temporal complementarity between solar and wind energies (solar-wind complementarity). The proposed framework considers the cost of energy production from different RESs and the cost of bi-directional energy exchange with the main grid. For a given RES mix, a minimum system power loss (SPL) threshold can also be determined. However, at this SPL threshold, MG energy exchange cost is not always minimized. The framework determines the optimized SPL value (above the threshold) at which MG energy exchange cost gets minimized. Through this framework, MG operator can decide appropriate RES mix and can achieve various tradeoffs according to the energy production cost, solar-wind complementarity of the site and its required economic objectives
Acute-on-chronic Liver Failure: MELD Score 30-day Mortality Predictability and Etiology in a Pakistani Population
Background: Cirrhosis is a pathological condition that ultimately leads to liver failure. Acute on chronic liver failure (ACLF) has a high short term mortality rate. Viral hepatitis is the most common cause of liver failure in our local population. We carried out this study to identity the 30-day mortality and etiology of patients presenting with ACLF using Model for End-Stage Liver Disease (MELD) score predictability.
Methodology: This was a descriptive case series, conducted at Sheikh Zayed Hospital, Lahore, Pakistan from January 31, 2018 to July 30, 2018. One hundred and eighty five patients who met the inclusion criteria were enrolled using 95% confidence level and 4% margin of error. Data was entered and analyzed with SPSS version 23.0. Numerical variables including age was presented by Mean ± S.D. Categorical variables i.e. gender, etiology of acute-on-chronic liver failure and 30-day mortality were presented by frequency and percentage. Data was stratified for age, gender, duration of chronic liver disease and MELD grade to address the effect modifiers. Post-stratification chi-square test was calculated using 95% significance (p≤0.05).
Results: Majority of the enrolled patients were male (74.6%) while only 25.4% of the patients were female. One hundred and thirty patients (70.3%) had underlying viral hepatitis while twelve patients (6.5%) and forty three patients (23.2%) presented with alcoholic liver disease and drug-induced ACLF, respectively. Eighty patients (43.2%) died within 30 days of admission.The 30-day mortality with respect to MELD grade was statistically significant (p<0.001) with the highest mortality noted in grade-IV and thirty five patients (43.8%) dying within 30 days of admission (p<0.001). Grade-II and III MELD scores also contributed to the 30-day mortality with twenty three patients (28.8%) and nineteen patients (23.8%) dying within 30 days of admission (p<0.001).
Conclusion: MELD scores are able to accurately predict the short-term mortality in patients with ACLF and viral hepatitis was the most common etiology in our population. Early detection and use of appropriate prognostic models may alleviate mortality and morbidity in paitents with ACLF
The Effect of Fish Size and Condition on the Contents of Twelve Essential and Non Essential Elements in Aristichthys nobilis
The correlation coefficients between fish size (body weight and total length) and metal contents (Na, K, Ca, Mg, Mn, Fe, Cu, Zn, Cr, Co, Cd and Pb) in whole fish (Aristichthys nobilis) were determined. A total of 71 fish samples were collected from hatcheries and fish reservoirs located in Islamabad and Fatehjung. Highly significant (P<0.001) relationship between metal concentrations and fish size was found. Most of the metals (Na, K, Ca, Mg, Cu, Zn, Cr, Cd and Pb) showed an isometric increase, while Mn, Fe and Co showed an allometric increase in with increasing body weight. All metals showed isometric increase, while, Na, Mn, Fe, Cu, and Co showed positive allometric growth in relation to total length. The correlation coefficient (r) between different variables and wet body weight, condition factor was found highly significant (P<0.001) in examined fish except for Na, Ca, Cu, Zn, Cd and Pb while for total length the same results found except Ca, Cd, Zn and Pb. Variance inflation factor values of regression coefficients in multiple regression analysis for each variable were lesser than 10. The metal levels of the examined fish were lower than the recommended values in fish and fishery products set by FAO
Identifying Users with Wearable Sensors based on Activity Patterns
We live in a world where ubiquitous systems surround us in the form of automated homes, smart appliances and wearable devices. These ubiquitous systems not only enhance productivity but can also provide assistance given a variety of different scenarios. However, these systems are vulnerable to the risk of unauthorized access, hence the ability to authenticate the end-user seamlessly and securely is important. This paper presents an approach for user identification given the physical activity patterns captured using on-body wearable sensors, such as accelerometer, gyroscope, and magnetometer. Three machine learning classifiers have been used to discover the activity patterns of users given the data captured from wearable sensors. The recognition results prove that the proposed scheme can effectively recognize a user’s identity based on his/her daily living physical activity patterns
Gauged linear sigma model and pion-pion scattering
A simple gauged linear sigma model with several parameters to take the
symmetry breaking and the mass differences between the vector meson and the
axial vector meson into account is considered here as a possibly useful
template for the role of a light scalar in QCD as well as for (at a different
scale) an effective Higgs sector for some recently proposed walking technicolor
models. An analytic procedure is first developed for relating the Lagrangian
parameters to four well established (in the QCD application) experimental
inputs. One simple equation distinguishes three different cases:1. QCD with
axial vector particle heavier than vector particle, 2. possible technicolor
model with vector particle heavier than the axial vector one, 3. the unphysical
QCD case where both the KSRF and Weinberg relations hold. The model is applied
to the s-wave pion-pion scattering in QCD. Both the near threshold region and
(with an assumed unitarization) theglobal region up to about 800 MeV are
considered. It is noted that there is a little tension between the choice of
bare sigma mass parameter for describing these two regions. If a reasonable
globa fit is made, there is some loss of precision in the near threshold
region.Comment: 19 pages, 9 figure
Optical Coherence Tomography Angiography Vessel Density in Healthy, Glaucoma Suspect, and Glaucoma Eyes.
PurposeThe purpose of this study was to compare retinal nerve fiber layer (RNFL) thickness and optical coherence tomography angiography (OCT-A) retinal vasculature measurements in healthy, glaucoma suspect, and glaucoma patients.MethodsTwo hundred sixty-one eyes of 164 healthy, glaucoma suspect, and open-angle glaucoma (OAG) participants from the Diagnostic Innovations in Glaucoma Study with good quality OCT-A images were included. Retinal vasculature information was summarized as a vessel density map and as vessel density (%), which is the proportion of flowing vessel area over the total area evaluated. Two vessel density measurements extracted from the RNFL were analyzed: (1) circumpapillary vessel density (cpVD) measured in a 750-μm-wide elliptical annulus around the disc and (2) whole image vessel density (wiVD) measured over the entire image. Areas under the receiver operating characteristic curves (AUROC) were used to evaluate diagnostic accuracy.ResultsAge-adjusted mean vessel density was significantly lower in OAG eyes compared with glaucoma suspects and healthy eyes. (cpVD: 55.1 ± 7%, 60.3 ± 5%, and 64.2 ± 3%, respectively; P < 0.001; and wiVD: 46.2 ± 6%, 51.3 ± 5%, and 56.6 ± 3%, respectively; P < 0.001). For differentiating between glaucoma and healthy eyes, the age-adjusted AUROC was highest for wiVD (0.94), followed by RNFL thickness (0.92) and cpVD (0.83). The AUROCs for differentiating between healthy and glaucoma suspect eyes were highest for wiVD (0.70), followed by cpVD (0.65) and RNFL thickness (0.65).ConclusionsOptical coherence tomography angiography vessel density had similar diagnostic accuracy to RNFL thickness measurements for differentiating between healthy and glaucoma eyes. These results suggest that OCT-A measurements reflect damage to tissues relevant to the pathophysiology of OAG
Culturally Adapted Interventions in Mental Health: Global Position Statement
The preponderance of western psychological concepts are often relied upon to conceptualise health-related phenomena. It is hardly surprising therefore that despite the availability of a number of interventions, studies have concluded that outcomes for minority cultural groups are not as good as for Caucasian people (western Europe and North America) in many high and middle income countries (HMIC). The evidence base of most psychosocial interventions is yet to be established in Low and Middle Income Countries (LMICs). There has been a propensity in some quarters to view low and middle income countries as passive beneficiaries of mental health knowledge, rather than as contributors or partners in knowledge production and development. A move towards a more equal bilateral relationship is called for, which should lead to better service provision. This Position Statement aims to highlight the current position and need for culturally adapted interventions. It is a global call for action to achieve a standardised mechanism to achieve parity of access and outcomes across all cultural groups regardless of country of residence
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