Tunneling with the Lorentz Force and the Friction

We present a semiclassical study of a transport process, the tunneling, in the presence of a magnetic field and a dissipative environment. We have found that the problem can be mapped onto an effective one-dimensional one, and the tunneling rate is strongly affected by the magnetic field, such as a complete suppression by a large parallel magnetic field, an example of the dynamical localization. In such case a small perpendicular component of the field, or the dissipation, can enhance the tunneling rate. In the small parallel field and finite temperatures the tunneling rate is finite. Explicit expressions will be presented in those cases. If viewing the tunneling in the presence of a magnetic field as a dissipative tunneling process, by varying the magnetic field and the potential one can obtain the dissipative spectral function between the subohmic $s =0$ and the superohmic $s = \infty$. In combination with a real dissipative spectral function, the effect of the magnetic field can map the spectral function from $s$ to $2-s$, with $s>2$ mapping to $s = 0$, revealing a dual symmetry between the friction and the Lorentz force. Two cases relevant to experiments, the edge state tunneling in a Hall bar and the tunneling near the dynamical localization will be discussed in detail.Comment: Late

Motion of Vacancies in a Pinned Vortex Lattice: Origin of the Hall Anomaly

Physical arguments are presented to show that the Hall anomaly is an effect of the vortex many-body correlation rather than that of an individual vortex. Quantitatively, the characteristic energy scale in the problem, the vortex vacancy formation energy, is obtained for thin films. At low temperatures a scaling relation between the Hall and longitudinal resistivities is found, with the power depending on sample details. Near the superconducting transition temperature and for small magnetic fields the Hall conductivity is found to be proportional to the inverse of the magnetic field and to the quadratic of the difference between the measured and the transition temperatures.Comment: minor change

Two Stages in the evolution of binary alkali Bose-Einstein condensate mixtures towards phase segregation

Two stages of quantum spinodal decomposition is proposed and analyzed for this highly non-equilibrium process. Both time and spatial scales for the process are found. Qualitative agreement with existing data is found. Some cases the agreements are quantitative. Further experimental verifications are indicated.Comment: late

Dissipative Tunneling in 2 DEG: Effect of Magnetic Field, Impurity and Temperature

We have studied the transport process in the two dimensional electron gas (2DEG) in presence of a magnetic field and a dissipative environment at temperature T. By means of imaginary time series functional integral method we calculate the decay rates at finite temperature and in the presence of dissipation. We have studied decay rates for wide range of temperatures -- from the thermally activated region to very low temperature region where the system decays by quantum tunneling. We have shown that dissipation and impurity helps the tunneling. We have also shown that tunneling is strongly affected by the magnetic field. We have demonstrated analytical results for all the cases mentioned above.Comment: 8 pages, 2 figure

Pattern of Urine Toxicology Screening in a Lagos Psychiatric Hospital

Toxicology screening has clinical and forensic applications in evaluating severe or life-threatening symptoms in patients presenting with signs and symptoms suggestive of intoxication or overdose. In both acute psychiatric and medical settings, urine toxicology has been found helpful in detection of substances of abuse. The aim of this study was to determine the pattern of substance use as detected by urine toxicology screening amongst patients at a psychiatric facility in Lagos Nigeria. A Total of 1555 subjects made up of males (1480) and females (75) were screened using the one step multi-6 drug test panel immunoassay for qualitative detection of Methadone, Methamphetamine, Benzodiazepine, Cocaine, Morphine and Tetrahydrocannabinol. 927 (59.6%) subjects were positive with one or more drugs passing the concentration cut off. Tetrahydrocannabinol (42.3%) and Benzodiazepine (49%) were found to be predominant in the population studied. This study shows the most common psychoactive substance used in this environment is cannabis and also, the significant agreement between clinical diagnosis and urine toxicology screening.Keywords: Urine screening, Toxicology, Substance use, clinical diagnosi

Factors influencing direct costs dynamics of building projects - team members perception in Delta state, Nigeria

Inaccurate costs forecast of building projects is traceable to variation in direct and indirect costs caused by several factors. This study evaluates the severity of the impact of eighty factors responsible for direct costs  dynamics of building projects in Delta State, Nigeria. The objective is to compare consultants and contractors perception of the severity of the  factors on direct costs differential. A field survey of 85 contractors and 67 consultants was conducted with the aid of structured questionnaires. Data were analysed using mean score, Mann-Whitney U and Kruskal Wallis  tests. The study concludes that consultants and contractors have similar  perception of the effect of the direct cost variation factors (p-values  between 0.365 and 0.930). Construction, resources, and performance  factors are the most significant of the groups (MS range = 3.66 to 4.33), though no significant variation among groups’ importance in the evaluation (p-values = 0.42 and 0.19). The study recommends that clients should  count on consultants and contractors for direct cost advice, provided they accommodate all the direct cost variation groups during cost advice, with priority on the leading factors of each group. Key words: Building projects, Consultants, Contractors, Cost dynamics, Direct costs

Profit Efficiency in Poultry Production in Peri-Urban Lagos, Nigeria

The study was conducted to determine the profit efficiency of poultry production in four peri-urban Local Government Areas in Lagos state. A total of ninety-six poultry farms involved in the survey were selected using a two-stage sampling technique. An average farmer in the sample was 40 years old; 85% were males and 84% had tertiary education. Most poultry farm in the sample had flock size that range between 500 and 2500. Prices of all the variable inputs significantly influence the profit of poultry farms while that of fixed inputs have no significant effect. The result indicates that the poultry farmers are not fully profit efficient. The mean efficiency estimated was 72 percent indicating that there was a 23 percent allowance to improve efficiency. Furthermore, the result shows that gender, family farm, finance, number of broilers and fulltime employment are the determinants of profit (technical and allocative) efficiency.Key Words: Poultry, Production, Profit, Efficiency, Nigeri

Carbon Monoxide as Indoor Pollutant in Kano Metropolis

The level of carbon monoxide concentrations in three different residential areas of Kano municipality has been determined. Health effects of carbon monoxide are not only determined by its pollution level, but the time spent breathing polluted air. Samples of carbon monoxide gas in three different residential districts within the Kano Metropolis; the high (city), medium (Sabon gari) and low (Nassarawa) density residential districts were assessed. The frequency distribution pattern for the gas is skewed towards high frequency of low concentration with a mean and standard deviation of 4.93 ± 3.08ìg/m3. Evidence linking high level of indoor carbon monoxide tolow birth weight and increase in prenatal deaths necessitates the need to periodically check the levels of the gas within each house hold in the metropoli

Psychological distress and symptoms among patients attending sexually transmitted infections clinic in Lagos, Nigeria

Background: The study was carried out to investigate the manifestations of psychological distress and symptoms among individuals receiving treatment for sexually transmitted diseases and to compare them with individuals who were not suffering from sexually transmitted diseases.Methods: Patients attending the sexually transmitted disease clinic of the Lagos State University Teaching Hospital, Ikeja, Lagos were recruited for this study; while the comparison group (n=50) was made up of participants attending the outpatient clinic of the University of Lagos Medical Centre, Akoka, Lagos. The participants completed the Symptoms Distress Checklist-90 (SLC-90) and Psychophysiological Symptoms Checklist (PSC).Results: The findings showed that 80% were males. The ages of the respondents ranged from 22 to 52 years, with a mean of 31.4 years. The participants in the study group obtained higher mean scores on interpersonal sensitivity (C), depression (D), anxiety (E) and hostility (F). The participants in the study group also had higher mean score in the PSC than those in the control group. Significant differences were found in SLC-(B) obsessive-compulsive, (E) anxiety and (F) Hostility. Of the total participants, 15 (30%) of the study group had previous STI infections when compared to 3 (6%) of the comparison group.Conclusion: It is suggested that clinicians running the sexually transmitted diseases should screen their patients for psychological disturbances and also work with mental health experts to provide psychological services for identified patients suffering from psychological distress among those attending the STI clinic.Keywords: Psychological reactions, sexually transmitted infections, Lagos, Nigeri