A skin colour code for the Nigerian (Negroid) population

Some researchers have codified various people of different racial and pigment backgrounds into skin types. The West African native population generally falls into type VI –least likely to burn. There is a need for skin colour code in a multiethnic country like Nigeria especially for the purpose of health matters. The human eye is still the most accurate instrument for the measurement of colour; its interpretation however is subjective. An objective form of documentation is needed that will be simple, quick and inexpensive. To meet the challenge for the development of a skin colour code for Nigerians, a study was conducted at the University College Hospital (UCH) Ibadan, Nigeria. The study aimed at visually identifying possible skin colours and to reproduce this on the computer. 40 colour chips were identified and found relevant for the Negroid skin in Nigeria including the Nigerian albino. The chart can be laminated using thin transparent plastic film to prevent transmission of infection from skin to skin in different people. A skin colour code can be useful for clinical evaluation of disease conditions like vitiligo as well as for epidemiological studies. Its diagnostic potential is yet to be assessed. African Journal of Health Sciences Vol. 13 (1-2) 2008: pp. 96-10

Dirac point resonances due to atoms and molecules adsorbed on graphene and transport gaps and conductance quantization in graphene nanoribbons with covalently bonded adsorbates

We present a tight binding theory of the Dirac point resonances due to adsorbed atoms and molecules on an infinite 2D graphene sheet based on the standard tight binding model of the graphene p-band electronic structure and the extended Huckel model of the adsorbate and nearby graphene carbon atoms. The relaxed atomic geometries of the adsorbates and graphene are calculated using density functional theory. Our model includes the effects of the local rehybridization of the graphene from the sp^2 to sp^3 electronic structure that occurs when adsorbed atoms or molecules bond covalently to the graphene. Unlike in previous tight-binding models of Dirac point resonances, adsorbed species with multiple extended molecular orbitals and bonding to more than one graphene carbon atom are treated. More accurate and more general analytic expressions for the Green's function matrix elements that enter the T-matrix theory of Dirac point resonances than have been available previously are obtained. We study H, F, OH and O adsorbates on graphene and for each we find a strong scattering resonance (two resonances for O) near the Dirac point of graphene, by far the strongest and closest to the Dirac point being the resonance for H. We extract a minimal set of tight binding parameters that can be used to model resonant electron scattering and electron transport in graphene and graphene nanostructures with adsorbed H, F, OH and O accurately and efficiently. We also compare our results for the properties of Dirac point resonances due to adsorbates on graphene with those obtained by others using density functional theory-based electronic structure calculations, and discuss their relative merits. We then present calculations of electronic quantum transport in graphene nanoribbons with these adsorbed species...Comment: 21 pages, 9 figure

Emergence of Thermodynamics from Darwinian Dynamics

Darwinian dynamics is manifestly stochastic and nonconservative, but has a profound connection to conservative dynamics in physics. In the present paper the main ideas and logical steps leading to thermodynamics from Darwinian dynamics are discussed in a quantitative manner. A synthesis between nonequilibrum dynamics and conservative dynamics is outlined.Comment: latex, 8 page

Challenges of dermatology training among internal medicine resident doctors in Nigeria

Background: The scope of dermatology training varies in teaching hospitals across Nigeria. In some institutions, there is a department of dermatology while in others it is a unit in the internal medicine department. Some medical schools have clinical postings in dermatology while others do not. Although the number of dermatologists in the country has increased compared with a few years back when they were a handful, the numbers are still inadequate to train other health practitioners on skin disorders and to meet the needs of patients. The objective of the study was to determine the perceived challenges by residents with regards to dermatology training so as to provide adequate training and ultimately increase the number of dermatologist in the country Methods: This was a cross-sectional descriptive study among resident doctors in internal medicine attending the update course of the National Postgraduate Medical College in April 2012 at Lagos using a selfadministered questionnaire. Data was analysed with SPSS 16. Result: Ninety resident doctors (58 pre-part 1 and 32 post part 1) answered the questionnaire. Seventy two (80.9%) had at least one dermatologist currently in their training institution. Sixty seven (76.1%) of the respondents (35 pre-part 1 and 32 post-part 1) had undergone postings in dermatology. The length of training varied from 1- 6 months. Sixty (66.7%) of the residents had dermatology posting as undergraduates in medical school with the length of the posting ranging from 2-6 weeks (30.0% for two weeks, 23.3% for four weeks and 41.7% for more than four weeks). Residents felt they had inadequate exposure to procedural dermatology (surgery, lasers, aesthetic), dermatopathology and management of wounds. Inadequate research opportunity (55.9%), inadequate mentors (53.2%), and inadequate facilities (53.2%) were more important challenges to dermatology training perceived by more than 50% of the residents.Conclusion: Dermatology training at both undergraduate and post graduate level in Nigeria is variable in content and duration amongst training institutions in Nigeria. There is need to standardise undergraduate and postgraduate Dermatology training. Training institution should operate a standard structured dermatology posting for undergraduate training and adhere to available curriculums provided by the postgraduate colleges for postgraduate training. Adequate facilities should be provided in the training centres and were these are not in place candidates should go to other centres with adequate training facilities for their postings

State-to-State Rotational Excitation of CO by H\u3csub\u3e2\u3c/sub\u3e Near 1000 cm\u3csup\u3e-1\u3c/sup\u3e Collision Energy

Relative state-to-state rotationally inelastic cross sections for excitation of carbon monoxide by hydrogen were measured in a crossed molecular beam experiment at collision energies 795, 860, and 991 cm-1. The results are compared to predictions of a recent ab initio potential energy surface [J. Chem. Phys. 108, 3554 (1998)]. The agreement is very good. A comparison with older data on thermally averaged total depopulation cross sections [Chem. Phys. 53, 165 (1980)] indicates that the absolute magnitudes of the cross sections predicted by the surface are too high. The CO excitation is dominated by collisions that are elastic in H2 rotation, and the collision dynamics are very similar for different rotational levels of hydrogen

Altimetry Using GPS-Reflection/Occultation Interferometry

A Global Positioning System (GPS)- reflection/occultation interferometry was examined as a means of altimetry of water and ice surfaces in polar regions. In GPS-reflection/occultation interferometry, a GPS receiver aboard a satellite in a low orbit around the Earth is used to determine the temporally varying carrier- phase delay between (1) one component of a signal from a GPS transmitter propagating directly through the atmosphere just as the GPS transmitter falls below the horizon and (2) another component of the same signal, propagating along a slightly different path, reflected at glancing incidence upon the water or ice surface

Gene Copy Number Analysis for Family Data Using Semiparametric Copula Model

Gene copy number changes are common characteristics of many genetic disorders. A new technology, array comparative genomic hybridization (a-CGH), is widely used today to screen for gains and losses in cancers and other genetic diseases with high resolution at the genome level or for specific chromosomal region. Statistical methods for analyzing such a-CGH data have been developed. However, most of the existing methods are for unrelated individual data and the results from them provide explanation for horizontal variations in copy number changes. It is potentially meaningful to develop a statistical method that will allow for the analysis of family data to investigate the vertical kinship effects as well. Here we consider a semiparametric model based on clustering method in which the marginal distributions are estimated nonparametrically, and the familial dependence structure is modeled by copula. The model is illustrated and evaluated using simulated data. Our results show that the proposed method is more robust than the commonly used multivariate normal model. Finally, we demonstrated the utility of our method using a real dataset

State to State Ne-CO Rotationally Inelastic Scattering

Measurements of state-to-state integral cross sections for rotational excitation of CO by collisions with Ne are reported. The measurements were performed in crossed molecular beams with resonance enhanced multiphoton detection at collision energies of 711 and 797 cm-1. The cross sections display strong interference structure, with a propensity for odd Δj below Δj=10. Predictions of the ab initio potential surface of Moszynski et al. [J. Phys. Chem. A 101, 4690 (1997)] and the new ab initio surface of McBane and Cybulski [J. Chem. Phys. 110, 11734 (1999), preceding paper] are compared to the data. The new surface agrees more closely with the observed interference structure, although significant disagreements remain

State to State He-CO Rotationally Inelastic Scattering

Relative integral cross sections for rotational excitation of CO in collisions with He were measured at energies of 72 and 89 meV. The cross sections are sensitive to anisotrophy in the repulsive wall of the He-CO interaction. The experiments were done in crossed molecular beams with resonance enhanced multiphoton ionization detection. The observed cross sections display interference structure at low Δj, despite the average over the initial CO rotational distribution. At higher Δj, the cross sections decrease smoothly. The results are compared with cross sections calculated from two high quality potential energy surfaces for the He-CO interaction. The ab initio SAPT surface of Heijmen et al. [J. Chem. Phys. 107, 9921 (1997)] agrees with the data better than the XC(fit) surface of Le Roy et al. [Farad. Disc. 97, 81 (1994)]

A study of genetic association with electrophysiological measures related to alcoholism: GAW14 data

Recently, alcohol-related traits have been shown to have a genetic component. Here, we study the association of specific genetic measures in one of the three sets of electrophysiological measures in families with alcoholism distributed as part of the Genetic Analysis Workshop 14 data, the NTTH (non-target case of Visual Oddball experiment for 4 electrode placements) phenotypes: ntth1, ntth2, ntth3, and ntth4. We focused on the analysis of the 786 Affymetrix markers on chromosome 4. Our desire was to find at least a partial answer to the question of whether ntth1, ntth2, ntth3, and ntth4 are separately or jointly genetically controlled, so we studied the principal components that explain most of the covariation of the four quantitative traits. The first principal component, which explains 70% of the covariation, showed association but not genetic linkage to two markers: tsc0272102 and tsc0560854. On the other hand, ntth1 appeared to be the trait driving the variation in the second principal component, which showed association and genetic linkage at markers in four regions: tsc0045058, tsc1213381, tsc0055068, and tsc0051777 at map distances 53.26, 85.42, 89.31, and 172.86, respectively. These results show that the partial answer to our starting question for this brief analysis is that the NTTH phenotypes are not jointly genetically controlled. The component ntth1 displays marked genetic linkage