Empirical Research Plan: Effects of Sketching on Program Comprehension

Sketching is an important means of communication in software engineering practice. Yet, there is little research investigating the use of sketches. We want to contribute a better understanding of sketching, in particular its use during program comprehension. We propose a controlled experiment to investigate the effectiveness and efficiency of program comprehension with the support of sketches as well as what sketches are used in what way.Comment: 5 pages, 0 figures, Proc. International Conference on Agile Software Development (XP'16). Volume 251 of the book series Lecture Notes in Business Information Processing (LNBIP). Springer, 201

Inequalities for characteristic numbers of flags of distributions and foliations

We prove inequalities relating the degrees of holomorphic distributions and of holomorphic foliations forming a flag on $\mathbb{P}^n$. Such inequalities are inspired by the so called Poincar\'e problem for foliations.Comment: Several minor clarifications and correction

Substance abuse and adherence to antiretroviral therapy among patients attending clinic at a specialist hospital in Jos, Nigeria

Substance abuse does not only increase susceptibility to HIV/AIDS through high risk Sexual behaviors but it also hastens the progression of the disease among infected persons than in those who do not abuse drugs. Furthermore, drug use impairs adherence to antiretroviral therapy (ART) leading to reduction in ART effectiveness and ultimately increased HIV-related mortality. In North Central Nigeria there is a dearth of information concerning the influence of substance abuse on adherence to ART which has substantially altered the fate of HIV-infected people. The objectives of this study therefore, were to determine the type of substances abused by HIV-infected patients attending clinic at Plateau State Specialists Hospital (PSSH) and to determine the effect of substance abuse and sociodemographic factors on adherence to ART among these patients. Ethical approval was obtained before the commencement of the study which was crosssectional in design. The study was carried out at the infectious disease unit of the Plateau State Specialists Hospital, Jos among 160 consecutive patients. The Alcohol, Smoking and Substance Involvement Screening Test (ASSIST) was used for the assessment of the types of substance abused and AIDS Clinical Trials Group(ACTG) adherence instrument was used to assess reasons for non- adherence. The results showed that 61.9% of the patients did not use any substance of abuse, 38.1% either abused one substance or a combination of substances. Substance abuse were (p = 0.0001), alcohol abuse (p = 0.003) and educational status (p = 0.0001) significantly associated with non-adherence to ART while, age (p = 0.954), employment status (p = 0.924) and marital status (p = 0.466) were not. However, logistic regression revealed that only alcohol abuse (B = -1.383, df = 1, p = .002) predicted non adherence to ART. We recommend the screening of patients on ART for substance abuse and a multi-disciplinary approach to the treatment of HIV/AIDS.Keywords: HIV, substance abuse, medication adherenc

Cluster Morphologies as a Test of Different Cosmological Models

We investigate how cluster morphology is affected by the cosmological constant in low-density universes. Using high-resolution cosmological N-body/SPH simulations of flat (\Omega_0 = 0.3, \lambda_0 = 0.7, \Lambda CDM) and open (\Omega_0 = 0.3, \lambda_0 = 0, OCDM) cold dark matter universes, we calculate statistical indicators to quantify the irregularity of the cluster morphologies. We study axial ratios, center shifts, cluster clumpiness, and multipole moment power ratios as indicators for the simulated clusters at z=0 and 0.5. Some of these indicators are calculated for both the X-ray surface brightness and projected mass distributions. In \Lambda CDM all these indicators tend to be larger than those in OCDM at z=0. This result is consistent with the analytical prediction of Richstone, Loeb, & Turner, that is, clusters in \Lambda CDM are formed later than in OCDM, and have more substructure at z=0. We make a Kolmogorov-Smirnov test on each indicator for these two models. We then find that the results for the multipole moment power ratios and the center shifts for the X-ray surface brightness are under the significance level (5%). We results also show that these two cosmological models can be distinguished more clearly at z=0 than z = 0.5 by these indicators.Comment: 30pages, 6figures, Accepted for publication in Ap

The Role of Collective Neutrino Flavor Oscillations in Core-Collapse Supernova Shock Revival

We explore the effects of collective neutrino flavor oscillations due to neutrino-neutrino interactions on the neutrino heating behind a stalled core-collapse supernova shock. We carry out axisymmetric (2D) radiation-hydrodynamic core-collapse supernova simulations, tracking the first 400 ms of the post-core-bounce evolution in 11.2 solar mass and 15 solar mass progenitor stars. Using inputs from these 2D simulations, we perform neutrino flavor oscillation calculations in multi-energy single-angle and multi-angle single-energy approximations. Our results show that flavor conversions do not set in until close to or outside the stalled shock, enhancing heating by not more than a few percent in the most optimistic case. Consequently, we conclude that the postbounce pre-explosion dynamics of standard core-collapse supernovae remains unaffected by neutrino oscillations. Multi-angle effects in regions of high electron density can further inhibit collective oscillations, strengthening our conclusion.Comment: v2: Added multi-angle calculations. Conclusions unchanged. 16 pages, 7 figures. Accepted to Phys. Rev. D after revisions: 15 Sept 2011 (major), 24 Jan 2012 (minor

Sociodemographic predictors of depression among survivors of armed conflict with posttraumatic stress disorder in Dogonahawa, north central Nigeria

Background: Survivors of mass violence are at high risk of developing a wide range of psychological disorders. Nevertheless, little is known about the impact of trauma in post conflict low-income countries where armed conflict abounds.Objective: This study was carried out to assess the prevalence of comorbid  depression among victims of armed- conflict in Dogonahawa, north-central Nigeria who developed posttraumatic stress disorder (PTSD) and those who did not. It also assessed the socio-demographic predictors for comorbid depression among those who developed PTSD.Method: A cross-sectional study that employed a multi stage sampling technique to select eligible subjects in Dogonahawa, north-central Nigeria. The PTSD module of Mini International Neuropsychiatric Interview (MINI) was used to assess for current symptoms of PTSD, while the Beck Depression Inventory-II (BDI-II) was used to assess for depression.Results: The results showed that 55.5% and 44.7% of the respondents had PTSD and PTSD with comorbid depression respectively. The difference in prevalence was statistically significant with adults diagnosed with PTSD in this community being significantly more likely to experience comorbid depression than those without PTSD (p< 0.001). Being a female gender and being the head of household were found to be the predictors for comorbid depression among respondents with PTSD.Conclusions: Mental health consequences of conflict continued to endure four years after the armed conflict. In the light of the above, mental health emergency  interventions after exposure to traumatic event need to be developed to enhance healing and recovery.KeyWords: PTSD, co-morbid depression, sociodemographic predictors, depression, Armed, Conflict, Dogonahaw

Matrix Product Renormalization Group: Potential Universal Quantum Many-Body Solver

The density matrix renormalization group (DMRG) is a celebrated tensor network algorithm, which computes the ground states of one-dimensional quantum many-body systems very efficiently. Here we propose an improved formulation of continuous tensor network algorithms, which we name a matrix product renormalization group (MPRG). MPRG is a universal quantum many-body solver, which potentially works at both zero and finite temperatures, in two and higher dimensions, and is even applicable to open quantum systems. Furthermore, MPRG does not rely on any variational principles and thus supports any kind of non-Hermitian systems in any dimension. As a demonstration, we present critical properties of the Yang-Lee edge singularity in one dimension as a representative non-Hermitian system.Comment: 5 pages, 3 figures, 2 table

Impact of eV-mass sterile neutrinos on neutrino-driven supernova outflows

Motivated by recent hints for sterile neutrinos from the reactor anomaly, we study active-sterile conversions in a three-flavor scenario (2 active + 1 sterile families) for three different representative times during the neutrino-cooling evolution of the proto-neutron star born in an electron-capture supernova. In our "early model" (0.5 s post bounce), the nu_e-nu_s MSW effect driven by Delta m^2=2.35 eV^2 is dominated by ordinary matter and leads to a complete nu_e-nu_s swap with little or no trace of collective flavor oscillations. In our "intermediate" (2.9 s p.b.) and "late models" (6.5 s p.b.), neutrinos themselves significantly modify the nu_e-nu_s matter effect, and, in particular in the late model, nu-nu refraction strongly reduces the matter effect, largely suppressing the overall nu_e-nu_s MSW conversion. This phenomenon has not been reported in previous studies of active-sterile supernova neutrino oscillations. We always include the feedback effect on the electron fraction Y_e due to neutrino oscillations. In all examples, Y_e is reduced and therefore the presence of sterile neutrinos can affect the conditions for heavy-element formation in the supernova ejecta, even if probably not enabling the r-process in the investigated outflows of an electron-capture supernova. The impact of neutrino-neutrino refraction is strong but complicated, leaving open the possibility that with a more complete treatment, or for other supernova models, active-sterile neutrino oscillations could generate conditions suitable for the r-process.Comment: 23 pages, including 14 figures and 2 tables (minor changes in the text). Matches published version in JCA