Magnetic Properties of Dilute Alloys: Equations for Magnetization and its Structural Fluctuations

The dilute Heisenberg ferromagnet is studied taking into account fluctuations of magnetization caused by disorder. A self-consistent system of equations for magnetization and its mean quadratic fluctuations is derived within the configurationally averaged two-time temperature Green's function method. This system of equations is analised at low concentration of non-magnetic impurities. Mean relative quadratic fluctuations of magnetization are revealed to be proportional to the square of concentration of impurities.Comment: 16 pages, LaTe

Current and historical involvement of dentistry in child protection and a glimpse of the future.

Dental teams have been involved with child protection for over 40 years. This brief review summarises their involvement in the detection of various types of child abuse and goes on to discuss the gap between the proportions of dental professionals who suspect child abuse or neglect in their paediatric patients and those who refer such cases on. Potential reasons for this discrepancy are discussed, and a glimpse of the future is given as to where further research may be necessary to tackle this existing gap

Return Of The Native: Historical Comparison Of Invasive And Indigenous Crab Populations Near The Mouth Of Delaware Bay

An invasive population of the Asian shore crab Hemigrapsus sanguineus was discovered in 1988 near the mouth of Delaware Bay, and populations now occur from North Carolina to Maine. The shore crab H. sanguineus competes with indigenous species and has displaced resident crabs throughout its invasive range. However, there have been few studies that document changes in populations of H. sanguineus after the species has become established. We compare sympatric populations of the Asian shore crab and a native mud crab (Panopeus herbstii) that were monitored initially in 2001 and again in 2011 and 2012. The historical study was conducted in a rocky habitat near Cape Henlopen at the southern terminus of Delaware Bay (38.793 degrees N, 75.158 degrees W). Results showed large differences in the relative abundance of the two species throughout the duration of the study. The Asian shore crab H. sanguineus accounted for 75% of total crab abundance in 2001, but abundance had decreased to less than 25% in both 2011 and 2012. Similar results were obtained when we compared the two species in terms of biomass. Additional sampling in 2012 showed comparable low values for H. sanguineus when compared with P. herbstii at two stations about 25 km and 50 km farther south along the coast. In contrast, H. sanguineus was strongly dominant at a station 50 km north of the historical sampling site. Percentage rock cover and size of rocks varied little among sampling locations, and all sites were proximal to the coastal ocean. However, basal sediment at the northern station was coarser than sediments at the other sites, which may have restricted the occurrence of mud crabs. Overall results of the study indicate a resurgence of native mud crabs at sites where sedimentary characteristics provide adequate habitat

Hyperglycemia Has a Greater Impact on Left Ventricle Function in South Asians Than in Europeans

OBJECTIVE Diabetes is associated with left ventricular (LV) diastolic and systolic dysfunction. South Asians may be at particular risk of developing LV dysfunction owing to a high prevalence of diabetes. We investigated the role of diabetes and hyperglycemia in LV dysfunction in a community-based cohort of older South Asians and white Europeans. RESEARCH DESIGN AND METHODS Conventional and Doppler echocardiography was performed in 999 participants (542 Europeans and 457 South Asians aged 58–86 years) in a population-based study. Anthropometry, fasting bloods, coronary artery calcification scoring, blood pressure, and renal function were measured. RESULTS Diabetes and hyperglycemia across the spectrum of HbA1c had a greater adverse effect on LV function in South Asians than Europeans (N-terminal-probrain natriuretic peptide β ± SE 0.09 ± 0.04, P = 0.01, vs. −0.04 ± 0.05, P = 0.4, P for HbA1c/ethnicity interaction 0.02), diastolic function (E/e′ 0.69 ± 0.12, P < 0.0001, vs. 0.09 ± 0.2, P = 0.6, P for interaction 0.005), and systolic function (s′ −0.11 ± 0.06, P = 0.04, vs. 0.14 ± 0.09, P = 0.1, P for interaction 0.2). Multivariable adjustment for hypertension, microvascular disease, LV mass, coronary disease, and dyslipidemia only partially accounted for the ethnic differences. Adverse LV function in diabetic South Asians could not be accounted for by poorer glycemic control or longer diabetes duration. CONCLUSIONS Diabetes and hyperglycemia have a greater adverse effect on LV function in South Asians than Europeans, incompletely explained by adverse risk factors. South Asians may require earlier and more aggressive treatment of their cardiometabolic risk factors to reduce risks of LV dysfunction

A Pair of Measures of Rotational Error for Axisymmetric Robot End-Effectors

International audienceThis paper deals with the problem of representing the rotational error of spatial robots with three orientational degrees of freedom (DOF). Typically, the errors on each of three Euler angles defining the orientation of an end-effector are analysed separately. However, this is wrong since an accuracy measure should depend only on the "distance" between the nominal pose and the actual one, and not on the choice of reference frame in which these are represented. Several bi-invariant metrics for rotational error exist but are single-parameter and, by definition, disregard the shape of the robot end-effector. Yet, robot end-effectors are typically axisymmetric. Therefore, we propose a two-parameter measure of rotational errors that is better suited for such robot end-effectors

Selection of tuning parameters in bridge regression models via Bayesian information criterion

We consider the bridge linear regression modeling, which can produce a sparse or non-sparse model. A crucial point in the model building process is the selection of adjusted parameters including a regularization parameter and a tuning parameter in bridge regression models. The choice of the adjusted parameters can be viewed as a model selection and evaluation problem. We propose a model selection criterion for evaluating bridge regression models in terms of Bayesian approach. This selection criterion enables us to select the adjusted parameters objectively. We investigate the effectiveness of our proposed modeling strategy through some numerical examples.Comment: 20 pages, 5 figure

Classification of non-Riemannian doubled-yet-gauged spacetime

Assuming $\mathbf{O}(D,D)$ covariant fields as the `fundamental' variables, Double Field Theory can accommodate novel geometries where a Riemannian metric cannot be defined, even locally. Here we present a complete classification of such non-Riemannian spacetimes in terms of two non-negative integers, $(n,\bar{n})$, $0\leq n+\bar{n}\leq D$. Upon these backgrounds, strings become chiral and anti-chiral over $n$ and $\bar{n}$ directions respectively, while particles and strings are frozen over the $n+\bar{n}$ directions. In particular, we identify $(0,0)$ as Riemannian manifolds, $(1,0)$ as non-relativistic spacetime, $(1,1)$ as Gomis-Ooguri non-relativistic string, $(D{-1},0)$ as ultra-relativistic Carroll geometry, and $(D,0)$ as Siegel's chiral string. Combined with a covariant Kaluza-Klein ansatz which we further spell, $(0,1)$ leads to Newton-Cartan gravity. Alternative to the conventional string compactifications on small manifolds, non-Riemannian spacetime such as $D=10$, $(3,3)$ may open a new scheme of the dimensional reduction from ten to four.Comment: 1+41 pages; v2) Refs added; v3) Published version; v4) Sign error in (2.51) correcte

Adverse effect of diabetes and hyperglycaemia on arterial stiffness in Europeans, South Asians, and African Caribbeans in the SABRE study

OBJECTIVES: Ethnic minority groups in the UK experience marked differences in cardiovascular disease risk. We investigated differences in arterial central haemodynamics, stiffness, and load in a tri-ethnic population-based cohort. METHODS: A total of 1312 participants (70 ± 6 years) underwent echocardiography and measurement of brachial and central blood pressure to assess central arterial haemodynamics including central pulse pressure (cPP), arterial stiffness [cPP/stroke volume (SV)], systemic vascular resistance (SVR), and load (Ea). RESULTS: Brachial and central SBPs were similar in all ethnic groups. Compared with Europeans, cPP, cPP/SV, and Ea were higher in South Asians. In contrast, cPP/SV was lower in African Caribbeans despite higher mean arterial pressure, higher SVR, and higher diabetes prevalence. cPP/SV and Ea remained significantly higher in South Asians and significantly lower in African Caribbeans after multivariate adjustment. Diabetes and higher HbA1c were more strongly associated with higher cPP/SV in South Asians than in Europeans (Pinteraction = 0.045 and 0.005, respectively); higher HbA1c was also more strongly associated with increased Ea in South Asians than Europeans (Pinteraction = 0.01). There was no evidence of an interaction between glycaemia and cPP/SV in African Caribbeans. CONCLUSIONS: Compared with Europeans, South Asians have unfavorable arterial function. Diabetes and hyperglycaemia have a more deleterious effect on cPP/SV and Ea in South Asians. In contrast, African Caribbeans have more favourable arterial function than Europeans and South Asians. These differences may contribute to the differential ethnic rates of cardiovascular disease

Quantum Aspects of Massive Gravity II: Non-Pauli-Fierz Theory

We investigate the non-Pauli-Fierz(nPF) theory, a linearized massive gravity with a generic graviton mass term, which has been ignored due to a ghost in its spectrum and the resultant loss of unitarity. We first show that it is possible to use the Lee-Wick mechanism, a unitarization through the decay of a ghost, in order to handle the sixth mode ghost of nPF, and then check for the quantum consistency. Once proven to be consistent, nPF could become a viable candidate for a large distance modification of gravity, because it naturally solves the intrinsic problems that most dark energy/modified gravity models suffer from: It smoothly converges to general relativity at short distances, and the small graviton mass necessary to modify gravity at large scales can be stable under the radiative corrections from the minimal gravity-to-matter coupling.Comment: 1+16pp, accepted for JHE

Tailoring force sensitivity and selectivity by microstructure engineering of multidirectional electronic skins

Electronic skins (e-skins) with high sensitivity to multidirectional mechanical stimuli are crucial for healthcare monitoring devices, robotics, and wearable sensors. In this study, we present piezoresistive e-skins with tunable force sensitivity and selectivity to multidirectional forces through the engineered microstructure geometries (i.e., dome, pyramid, and pillar). Depending on the microstructure geometry, distinct variations in contact area and localized stress distribution are observed under different mechanical forces (i.e., normal, shear, stretching, and bending), which critically affect the force sensitivity, selectivity, response/relaxation time, and mechanical stability of e-skins. Microdome structures present the best force sensitivities for normal, tensile, and bending stresses. In particular, microdome structures exhibit extremely high pressure sensitivities over broad pressure ranges (47,062 kPa(-1) in the range of &lt; 1 kPa, 90,657 kPa(-1) in the range of 1-10 kPa, and 30,214 kPa(-1) in the range of 10-26 kPa). On the other hand, for shear stress, micropillar structures exhibit the highest sensitivity. As proof-of-concept applications in healthcare monitoring devices, we show that our e-skins can precisely monitor acoustic waves, breathing, and human artery/carotid pulse pressures. Unveiling the relationship between the microstructure geometry of e-skins and their sensing capability would provide a platform for future development of high-performance microstructured e-skins