New selection rules for resonant Raman scattering on quantum wires

The bosonisation technique is used to calculate the resonant Raman spectrum of a quantum wire with two electronic sub-bands occupied. Close to resonance, the cross section at frequencies in the region of the inter sub-band transitions shows distinct peaks in parallel polarisation of the incident and scattered light that are signature of collective higher order spin density excitations. This is in striking contrast to the conventional selection rule for non-resonant Raman scattering according to which spin modes can appear only in perpendicular polarisation. We predict a new selection rule for the excitations observed near resonance, namely that, apart from charge density excitations, only spin modes with positive group velocities can appear as peaks in the spectra in parallel configuration close to resonance. The results are consistent with all of the presently available experimental data.Comment: 7 pages, 2 figure

Associations between maternal BMI, breastfeeding practices and infant anthropometric status in Colombia; secondary analysis of ENSIN 2010

BACKGROUND Maternal malnutrition and infant feeding mode impact short and long term infant and child morbidity and mortality. The period of lactation may provide an opportunity to modulate the risk of disease later in life. Our aim was to estimate the effect of maternal body mass index (BMI) and infant feeding mode, particularly breastfeeding practices, on the anthropometric status of children under 2 years in Colombia. METHODS A secondary analysis was performed using the data from ENSIN 2010. Term infants under 2y, singleton, with a mother older than 18y, were included in the analysis. Outcomes were wasting (WLZ  +2SD) and stunting (LAZ < -2SD). Predictors were infant feeding (exclusive and predominant BF constructed from 24-h recall, age at introduction of liquids, semisolids and solids) and maternal BMI. Socioeconomic variables, maternal education and age, conditions during pregnancy and birth weight were analyzed as covariates. RESULTS Mothers of overweight infants had higher BMI (Mean dif = 1.47 kg/m2; 95% CI = 2.1, 0.8) than those with normal weight infants. Stunting and wasting were not predicted by maternal anthropometry or infant feeding mode. Fewer maternal years of education were associated with wasting (OR = 0.90; 95% CI = 0.86, 0.97; p = 0.003) and stunting (OR = 0.92; 95% CI = 0.89, 0.94; p < 0.0001), while more maternal years of education were associated with overweight (OR = 1.06; 95% CI = 1.02, 1.01; p = 0.001); higher birth weight was associated with overweight (OR = 1.001; 95% CI = 1.00, 1.001; p < 0.0001) and lower birth was associated with stunting (OR = 0.99; 95% CI = 0.89; p < 0.0001) in the final regression model. CONCLUSIONS Maternal BMI is a modifiable target for public health policy to promote healthy infant growth. Infant nutritional status is affected by direct and indirect factors that need to be addressed in further studies

Effect of Pre-Ageing Thermal Conditions on the Corrosion Properties of Antimony-Modified Al-Si-Mg Alloy

The purpose of this investigation was to evaluate the effect of pre-ageing thermal conditions on the corrosion properties of antimony-modified Al-Si-Mg alloy.The alloy was subjected to a Single Thermal Ageing Treatment; STAT (T6 temper-solution heat treatment and ageing) and Double thermal ageing treatment; DTAT (T7 temper- solution heat treatment and ageing for stabilization). These consist of solution heat treatment (SHT) at 540oC for 1hr, water quenched followed by an artificial ageing; DTAT and STAT. For the single thermal ageing treatment (STAT), quenched samples were aged at temperatures of 1800C for 2hrs, before cooling in air. In the double thermal ageing treatment (DTAT), quenched samples were pre-aged at a temperature of 90oC, 105oC and 120oC for 1- 5 hrs. This was followed by ageing at 180oC for 2hrs before cooling in air. The corrosion characteristic of the as-cast, Single Thermal Ageing Treatment (STAT) and Double Thermal Ageing Treatment (DTAT) were evaluated using weight loss and linear polarization techniques in a static 3.5%NaCl solution. From the results, the corrosion rate decreases with increasing pre-ageing time and temperatures. Equally, from the linear polarization data/curves, the corrosion rate of the treated alloy decreases at all ageing temperatures along with the ageing time. The Optical Microscope (OM) results of as-corroded samples revealed that the alloy suffers pitting/uniform corrosion. The corrosion behaviour of the DTAT samples in simulated seawater showed an excellent improvement in corrosion resistance than the as-cast and conventional STAT alloy.http://dx.doi.org/10.4314/njt.v34i4.

Laser-induced charge and spin photocurrents at BiAg2_2 surface: a first principles benchmark

Here, we report first principles calculations and analysis of laser-induced photocurrents at the surface of a prototype Rashba system. By referring to Keldysh non-equilibrium formalism combined with the Wannier interpolation scheme we perform first-principles electronic structure calculations of a prototype BiAg$_2$ surface alloy, which is a well-known material realization of the Rashba model. In addition to non-magnetic ground state situation we also study the case of in-plane magnetized BiAg$_2$. We calculate the laser-induced charge photocurrents for the ferromagnetic case and the laser-induced spin photocurrents for both the non-magnetic and the ferromagnetic cases. Our results confirm the emergence of very large in-plane photocurrents as predicted by the Rashba model. The resulting photocurrents satisfy all the symmetry restrictions with respect to the light helicity and the magnetization direction. We provide microscopic insights into the symmetry and magnitude of the computed currents based on the ab-initio multi-band electronic structure of the system, and scrutinize the importance of resonant two-band and three-band transitions for driven currents, thereby establishing a benchmark picture of photocurrents at Rashba-like surfaces and interfaces. Our work contributes to the study of the role of the interfacial Rashba spin-orbit interaction as a mechanism for the generation of in-plane photocurrents, which are of great interest in the field of ultrafast and terahertz spintronics

Typhoid fever in children presenting to paediatric medical wards of Ahmadu Bello University Teaching Hospital Zaria: A 13-month review

Typhoid fever is a systemic infection caused by the Gram-negative bacilli Salmonellae, transmitted via the feaco-oral route. It commonly affects children, leading to complications and death if untreated. This is a reportof typhoid fever admissions as seen at ABU Teaching Hospital Zaria over a 13-month period. Objectives: To describe the clinical presentation and management outcomes of children admitted with typhoid fever during a13-month period.Materials and methods: A retrospective review of demographic, clinical presentation and treatment response of children managed for typhoid fever was conducted. Results were presented as means with standard deviation, proportions, tables, figures and Chisquares with p values. The prevalence of typhoid fever admissions was obtained over the period from2008-2011.Results: A total of 779 children were admitted from 1st January 2011 to 31st January 2012, out of which 39 (4.9%) had a diagnosis of typhoid fever. There was a significant difference in prevalence of typhoid fever admissions from 2008-2010 compared to 2011 (X2 = 5.6651; p &lt;0.019). The mean age was 7.2 (SD ± 4.3) years and 71.8% resided in the sameneighbourhood. All the children had pre-admission antibiotics, while 93.3% had abdominal pain, 64.1% had diarrhoea, 89.7% had fever and 69% had hepatomegaly. Widal test and blood cultures were positive in 46% and 10.3% respectively. Poor treatment response led to antibiotic switch for 61.1% started on chloramphenicol. Bowel perforation occurred in four(10.3%) who had laparotomy but there was no mortality, and all were discharged after recovery.Conclusion: A surge was observed in typhoid fever admissions associatedwith widespread use of preadmission antibiotics. Low rates of pathogen isolation and unaffordable costs precluded appropriate antibiotic choice for many at admission, and led to poor treatment response. Public health education should emphasize water hygiene and judicious use of antibiotics.Key words: Typhoid fever; Enteric fever; Children; Hospital admission

A review of implant provision for hypodontia patients within a Scottish referral centre

Background: Implant treatment to replace congenitally missing teeth often involves multidisciplinary input in a secondary care environment. High quality patient care requires an in-depth knowledge of treatment requirements. Aim: This service review aimed to determine treatment needs, efficiency of service and outcomes achieved in hypodontia patients. It also aimed to determine any specific difficulties encountered in service provision, and suggest methods to overcome these. Methods: Hypodontia patients in the Unit of Periodontics of the Scottish referral centre under consideration, who had implant placement and fixed restoration, or review completed over a 31 month period, were included. A standardised data collection form was developed and completed with reference to the patient's clinical record. Information was collected with regard to: the indication for implant treatment and its extent; the need for, complexity and duration of orthodontic treatment; the need for bone grafting and the techniques employed and indicators of implant success. Conclusion: Implant survival and success rates were high for those patients reviewed. Incidence of biological complications compared very favourably with the literature

Statistical properties of contact vectors

We study the statistical properties of contact vectors, a construct to characterize a protein's structure. The contact vector of an N-residue protein is a list of N integers n_i, representing the number of residues in contact with residue i. We study analytically (at mean-field level) and numerically the amount of structural information contained in a contact vector. Analytical calculations reveal that a large variance in the contact numbers reduces the degeneracy of the mapping between contact vectors and structures. Exact enumeration for lengths up to N=16 on the three dimensional cubic lattice indicates that the growth rate of number of contact vectors as a function of N is only 3% less than that for contact maps. In particular, for compact structures we present numerical evidence that, practically, each contact vector corresponds to only a handful of structures. We discuss how this information can be used for better structure prediction.Comment: 20 pages, 6 figure

Association Between Multiparametric Magnetic Resonance Imaging of the Prostate and Oncological Outcomes after Primary Treatment for Prostate Cancer: A Systematic Review and Meta-analysis

CONTEXT: The diagnostic accuracy of multiparametric magnetic resonance imaging (mpMRI) for prostate cancer (PCa) diagnosis has been extensively explored. Little is known about the prognostic value of mpMRI suspicion scores and other quantitative mpMRI information. OBJECTIVE: To systematically review the current literature assessing the relationship between pretreatment mpMRI and oncological outcomes after primary treatment for PCa to assess the role of mpMRI as a prognostic tool. EVIDENCE ACQUISITION: A computerized bibliographic search of MEDLINE/PubMed, EMBASE, Scopus, and the Cochrane Library CENTRAL databases was performed for all studies assessing the relationship between mpMRI and oncological outcomes after primary treatment for PCa. The review protocol is registered in the PROSPERO database (CRD42020209899). EVIDENCE SYNTHESIS: A total of six studies were included. Reliable evidence is still limited in this field. The Prostate Imaging-Reporting and Data System (PI-RADS) score was an independent predictor of biochemical recurrence (BCR) after radical prostatectomy (RP) in the majority of the studies included. The tumor volume at mpMRI was not significantly associated with BCR after RP for PCa. Data on disease progression and PCa-specific mortality are limited. Heterogeneity among the studies was substantial. CONCLUSIONS: The review shows that PI-RADS scores provide information on the future likelihood of cancer recurrence or progression, at least for men undergoing RP. We are of the view that this information should be taken into account to identify men at higher risk of unfavorable outcomes. PATIENT SUMMARY: A higher Prostate Imaging-Reporting and Data System score for magnetic resonance imaging of the prostate seems to be positively associated with oncological failure in prostate cancer and should be incorporated into future risk models