One-sided rectifying p-n junction diodes fabricated from n-CdS and p-ZnTe:Te semiconductors

The fabrication of a one-sided p-n hetero-junction (HJ) diodes have been successfully carried out using both p-type ZnTe and n-CdS semiconductors. Chemical bath deposition (CBD) and electrodeposition (ED) techniques have been used in the deposition of n-CdS and p-ZnTe layers respectively. Before the fabrication of the one-sided p-nHJ diodes, the electrical properties of glass/ FTO/p-ZnTe/Al and glass/FTO/n-CdS/Au rectifying structures were separately studied using capacitance-voltage (C-V ) technique so as to determine the doping density of each of the thin films. The results from C-V analyses showed that p-ZnTe is moderately doped with an acceptor density of 3.55×1015 cm3 while n-CdS is heavily doped with a donor density of 9.00×1019 cm3. The heavy doping of n-CdS and moderate doping of p-ZnTe will make the interface between n-CdS and p-ZnTe thin films a one-sided n+p diode. Therefore, to fabricate the CdS/ZnTe hetero-structure, it was ensured that approximately same thickness of CdS and ZnTe thin films being used in the initial experiment to study the electrical properties of glass/FTO/n-CdS/Au and glass/FTO/p-ZnTe/Al were also used in the development of the one-sided n+p junction diodes to obtain more accurate results. The electronic properties of the device structure were studied using both current-voltage (IV ) and C-V measurement techniques. The I-V results show that the one-sided n+pHJ diodes possess good rectifying quality with a series resistance (Rs) of35 and rectification factors exceeding 102.7 under dark condition. The results of theC-Vanalyses showed that the acceptor density of the onesided n+pHJ diode is of the order of 1015 cm3 while the donor density is of the order of 1018 cm3. The results obtained from this analysis still showed the moderate doping of p-ZnTe and the degenerate nature of n-CdS

Multiple shoot induction from embryo derived callus cultures of cowpea (Vigna unguiculata l.) Walp

The production of whole plant of cowpea (Vigna unguiculata) L. Walp from calli is an efficient, reliable and rapid strategy. This provides a faster method of micro propagation. Seeds of the pea were surface sterilized, and then the embryo axes were dissected and germinated. Callus growth was induced on thecut surface of the embryo of V. unguiculata. Root development in the cells was promoted by the action of the auxin, naphthalene acetic acid (NAA), at low cytokinin concentration. After five weeks, multiple shoots ranging from two to four developed from the calli cultures after being subcultured on media withhigh concentration of cytokinin, benzylaminopurine (BAP). Percentages shoot production from calli grown on media with 1 mM concentration of BAP was 45.5% while calli subcultured on 4 mM BAP produced 87.5% shoot production. Percentage rate of survival was between 21-26% in the hardened transplanted plantlets

Surface Acoustic Wave Single-Electron Interferometry

We propose an experiment to observe interference of a single electron as it is transported along two parallel quasi-one-dimensional channels trapped in a single minimum of a travelling periodic electric field. The experimental device is a modification of the surface acoustic wave (SAW) based quantum processor. Interference is achieved by creating a superposition of spatial wavefunctions between the two channels and inducing a relative phase shift via either a transverse electric field or a magnetic field. The interference can be used to estimate the decoherence time of an electron in this type of solid-state device

Prevalence of iron deficiency anaemia in anaemic under-5 children in Enugu South East Nigeria

Background: Iron deficiency anaemia has been described as the commonest type of nutritional anaemia in infancy and childhood. The associated adverse health sequelae include permanent behavioural and cognitive impairments. Early detection and prompt treatment are necessary to prevent these complications.Aim: To determine the prevalence and socio-demographic distribution of iron deficiency anaemia among anaemic under five children in Enugu.Subjects and methods: Under-five children presenting at a tertiary hospital were consecutively enrolled and screened for iron deficiency anaemia using haematocrit and serum ferritin levels. Iron deficiency anaemia was defined as haematocrit level <30% and ferritin level <12ng/ml.Results: Three hundred and twelve children (187 males, 125 females) aged below 60 months had a PCV check out of which 178 (57.1%) were anaemic (PCV< 30%). Of the anaemic group, 61(34.3%) had iron deficiency anaemia. Prevalence of iron deficiency anaemia was higher among the males (38.0%) [p=0.235], age group 13- 23months (40.0%) [p=0.575] and children from lower socioeconomic class (43.5%)[p=0.158]. There is a positive but weak correlation between serum ferritin and haematocrit levels [r= 0.11 p=0.130].Conclusion: The prevalence of iron deficiency anaemia in the study population was high and varies with the child’s age group, gender and parental socioeconomic class.Keywords: iron deficiency anaemia, serum ferritin, haemtocrit, Enugu

The use of behaviour management techniques amongst paediatric dentists working in the Arabian region: a cross‑sectional survey study

Purpose The purposes of this study were to investigate paediatric dental practitioners’ training and confidence in using dental behaviour management techniques in the Arabian region and to assess the factors influencing the application of advanced behaviour management techniques. Methods: An online questionnaire was distributed to paediatric dental practitioners in the Arabian region. Data were analysed using descriptive statistics and Pearson Chi Square. Results A total of 113 responses were obtained. Of these, the majority were from Egypt (45%, n = 51). Just over half of the respondents were registered as specialists at the country where they were practicing paediatric dentistry (53%, n = 60). The use of behaviour management techniques varied amongst participants with tell-show-do (95%, n = 107) and positive reinforcement (89%, n = 101) being the most routinely used techniques. The majority of participants reported using voice control (83%) and parental separation (68%) techniques. Hand over mouth exercise (HOME) was only used by 24% (n = 27) of participants, whilst just over half of the participants, 53%, reported using protective stabilisation. A significant association was shown between country of practice, country of obtaining paediatric dental training, speciality status and the use of advanced behaviour management techniques, whilst confidence in using HOME and sedation were associated with work setting and country of practice, respectively. Conclusion The use of advanced behaviour management techniques was found to be high amongst respondents in the Arabian region. The lack of training in using these techniques, however, is of concern. Further assessment of the factors affecting the use of and confidence in applying advanced behaviour management techniques in the Arabian region is needed

Comparison of homoeolocus organisation in paired BAC clones from white clover (Trifolium repens L.) and microcolinearity with model legume species

<p>Abstract</p> <p>Background</p> <p>White clover (<it>Trifolium repens </it>L.) is an outbreeding allotetraploid species and an important forage legume in temperate grassland agriculture. Comparison of sub-genome architecture and study of nucleotide sequence diversity within allopolyploids provides insight into evolutionary divergence mechanisms, and is also necessary for the development of whole-genome sequencing strategies. This study aimed to evaluate the degree of divergence between the O and P' sub-genomes of white clover through sequencing of BAC clones containing paired homoeoloci. The microsyntenic relationships between the genomes of white clover and the model legumes <it>Lotus japonicus </it>and <it>Medicago truncatula </it>as well as <it>Arabidopsis thaliana </it>were also characterised.</p> <p>Results</p> <p>A total of four paired homoeologous BACs were selected and sequenced to generate 173 kb of overlapping sequence between the O and P' sub-genomes. Equivalent gene content was generally observed, apart from small-scale deletions, in contrast to conservation of intergenic sequences, which varied between the four selected regions. Measurement of the number of synonymous substitutions between homoeologous genes led to estimation of a 4.2 million year divergence time between the two sub-genomes. Microsynteny was observed between the genomes of white clover and <it>L. japonicus </it>for all four targeted regions, but corresponding <it>M. truncatula </it>genomic regions were only identified for two BAC pairs.</p> <p>Conclusions</p> <p>This study describes the first analysis of sub-genome structural conservation across selected genomic regions in white clover. Although the high levels of sequence conservation between the O and P' sub-genomes would complicate efforts for whole genome sequence assembly, the conserved microsynteny with model legume genomes, especially that of <it>L. japonicus</it>, will be highly valuable for the future of white clover genomics and molecular breeding.</p

Are nonsingular black holes with super-Planckian hair ruled out by S2 star data?

We propose a novel nonsingular black-hole spacetime representing a strong deformation of the Schwarzschild solution with mass $M$ by an additional hair $\ell$, which may be hierarchically larger than the Planck scale. Our black-hole model presents a de Sitter core and $\mathcal{O}(\ell^2/r^2)$ slow-decaying corrections to the Schwarzschild solution. Our black-hole solutions are thermodynamically preferred when $0.2 \lesssim \ell/GM \lesssim \, 0.3$ and are characterized by strong deviations in the orbits of test particles from the Schwarzschild case. In particular, we find corrections to the perihelion precession angle scaling linearly with $\ell$. We test our model using the available data for the orbits of the S2 star around $\text{SgrA}^*$. These data strongly constrain the value of the hair $\ell$, casting an upper bound on it of $\sim \, 0.47 \, GM$, but do not rule out the possible existence of regular black holes with super-Planckian hair.Comment: 6 pages, 2 figures, 1 table. Revised version: Addendum and some references have been adde

Identifying a Two-State Hamiltonian in the Presence of Decoherence

Mapping the system evolution of a two-state system allows the determination of the effective system Hamiltonian directly. We show how this can be achieved even if the system is decohering appreciably over the observation time. A method to include various decoherence models is given and the limits of this technique are explored. This technique is applicable both to the problem of calibrating a control Hamiltonian for quantum computing applications and for precision experiments in two-state quantum systems. For simple models of decoherence, this method can be applied even when the decoherence time is comparable to the oscillation period of the system.Comment: 8 pages, 6 figures. Minor corrections, published versio

Identifying an Experimental Two-State Hamiltonian to Arbitrary Accuracy

Precision control of a quantum system requires accurate determination of the effective system Hamiltonian. We develop a method for estimating the Hamiltonian parameters for some unknown two-state system and providing uncertainty bounds on these parameters. This method requires only one measurement basis and the ability to initialise the system in some arbitrary state which is not an eigenstate of the Hamiltonian in question. The scaling of the uncertainty is studied for large numbers of measurements and found to be proportional to one on the square-root of the number of measurements.Comment: Minor corrections, Accepted for publication in Physical Review