Phase diagrams of period-4 spin chains consisting of three kinds of spins

We study a period-4 antiferromagnetic mixed quantum spin chain consisting of three kinds of spins. When the ground state is singlet, the spin magnitudes in a unit cell are arrayed as (s-t, s, s+t, s) with integer or half-odd integer s and t (0 <= t < s). The spin Hamiltonian is mapped onto a nonlinear sigma model (NLSM) in a previously developed method. The resultant NLSM includes only two independent parameters originating from four exchange constants for fixed s and t. The topological angle in the NLSM determines the gapless phase boundaries between disordered phases in the parameter space. The phase diagrams for various s and t shows rich structures. We systematically explain the phases in the singlet-cluster-solid picture.Comment: 8 pages (16 figures included

Analysis of organisational climate to improve the adequacy of primary health care in the State of Kuwait

This study covers two areas of contribution to the knowledge, firstly it tried to investigate rigourously the relationships of a number of factors believed that they may affect the climate perception, classified into three types to arrive to prove a hypothesis of the important role that qualification and personal factors play in shaping the climate perception, this is in contrast with situational factors. Secondly, the study tries to recluster the items of a wide-range applied scale for the measurement of climate named HAY in order to overcome the cross-cultural differences between the Kuwaiti and the American society, and to achieve a modified dimensions of climate for a civil service organisation in Kuwait. Furthermore, the study attempts to carry out a diagnostic test for the climate of the Ministry of Public Health in Kuwait, aiming to diagnose the perceived characteristics of the MoPH organisation, and suggests a number of areas to be given attention if an improvement is to be introduced. The study used extensively the statistical and the computer facilities to make the analysis more representing the field data, on the other hand this study is characterised by the very highly responsive rate of the main survey which would affect the findings reliability. Three main field studies are included, the first one was to conduct the main questionnaire where the second was to measure the "should be" climate by the experts of MoPH using the DELPHI technique, and the third was to conduct an extensive meeting with the very top management team in MoPH. Results of the first stage were subject to CLUSTER analysis for the reconstruction of the HAY tool, whereas comparative analysis was carried on between the results of the second and third stages on one side, the first from the other

Matter-positronium interaction: An exact diagonalization study of the He atom - positronium system

The many-body system comprising a He nucleus, three electrons, and a positron has been studied using the exact diagonalization technique. The purpose has been to clarify to which extent the system can be considered as a distinguishable positronium (Ps) atom interacting with a He atom and, thereby, to pave the way to a practical atomistic modeling of Ps states and annihilation in matter. The maximum value of the distance between the positron and the nucleus is constrained and the Ps atom at different distances from the nucleus is identified from the electron and positron densities, as well as from the electron-positron distance and center-of-mass distributions. The polarization of the Ps atom increases as its distance from the nucleus decreases. A depletion of the He electron density, particularly large at low density values, has been observed. The ortho-Ps pick-off annihilation rate calculated as the overlap of the positron and the free He electron densities has to be corrected for the observed depletion, specially at large pores/voids.Comment: 18 pages, 8 figure

The biomechanics of sensory organs

Studies of mechanosensory systems have largely focused on the filter characteristics of their neural components in relation to their ultimate function. Less attention has focused on the role of the physical structure of the sensory organ which also acts as a mechanical filter of the sensory input. This biomechanical filtering is readily apparent in the case of several mechanosensory systems that transduce information about the deformations of the sensory organs in response to external forces. Because these deformations critically depend on the geometry and material properties of the mechanosensory organs, it is necessary to conduct focused studies on the biomechanical characteristics of these organs when studying the encoding properties of the mechanosensory system. Modern experimental tools such as Laser Doppler Vibrometry and computational tools such as Computational Fluid Dynamics and Finite Element Analysis provide the means for determining the sensory pre-filtering properties of small-scale mechanosensory structures. In all the cases covered in this review, the physical properties of the sensory organs play a central role in determining the signals received by the nervous system

Isolated elliptical galaxies in the local Universe

We have studied a sample of 89 very isolated, elliptical galaxies at z < 0.08 and compared their properties with elliptical galaxies located in a high-density environment such as the Coma supercluster. Our aim is to probe the role of environment on the morphological transformation and quenching of elliptical galaxies as a function of mass. In addition, we elucidate the nature of a particular set of blue and star-forming isolated ellipticals identified here. We study physical properties of ellipticals such as color, specific star formation rate, galaxy size, and stellar age, as a function of stellar mass and environment based on SDSS data. We analyze the blue star-forming isolated ellipticals in more detail, through photometric characterization using GALFIT, and infer their star formation history using STARLIGHT. Among the isolated ellipticals ~ 20% are blue, 8% are star forming, and ~ 10% are recently quenched, while among the Coma ellipticals ~ 8% are blue and just <= 1% are star forming or recently quenched. There are four isolated galaxies (~ 4.5%) that are blue and star forming at the same time. These galaxies, with masses between 7 x 10^9 and 2 x 10^10 h-2 M_sun, are also the youngest galaxies with light-weighted stellar ages <= 1 Gyr and exhibit bluer colors toward the galaxy center. Around 30-60% of their present-day luminosity, but only < 5% of their present-day mass, is due to star formation in the last 1 Gyr. The processes of morphological transformation and quenching seem to be in general independent of environment since most of elliptical galaxies are 'red and dead', although the transition to the red sequence should be faster for isolated ellipticals. In some cases, the isolated environment seems to propitiate the rejuvenation of ellipticals by recent (< 1 Gyr) cold gas accretion.Comment: 23 pages, 15 figures (16 pages and 9 figures without appendices). A&A, in pres

Regional differences in long-term cycles and seasonality of Puumala virus infections, Finland, 1995-2014

Puumala hantavirus (PUUV) causes haemorrhagic fever with renal syndrome in humans, an endemic disease in Finland. We aimed to study recent trends in PUUV infections in Finland, to evaluate whether there are regional differences in seasonality and long-term cycles and whether the patterns have changed over time. We analysed serologically confirmed acute PUUV infections reported to the National Infectious Disease Register from 1 April 1995 to 31 March 2014. A total of 30 942 cases of PUUV infections were identified during the study period. The average annual incidence was 31 cases/100 000 person-years with the highest in Eastern Finland and the lowest in Southwestern Finland. Throughout Finland there was not an increasing trend in incidence but changes in incidence, seasonality and long-term cycles differed regionally. Long-term cycles supported by high Bayesian posterior probabilities (73-100%) differed between the south and the north, shifting from 3 to 4 years, respectively. Temporal changes in seasonality were most prominent in Southwestern Finland. The pattern of human PUUV infection epidemiology probably primarily reflects the spatio-temporal interaction between bank-vole population dynamics and climate.Peer reviewe

Zikavirus

English summaryPeer reviewe

Health Information-Seeking Patterns of the General Public and Indications for Disease Surveillance : Register-Based Study Using Lyme Disease

Peer reviewe

Seroprevalence of Lyme borreliosis in Finland 50 years ago

ObjectivesLyme borreliosis (LB) is a tick-borne infection common in Europe. In Finland, the LB seroprevalence in the healthy population was 3.9% in 2011. While the present-day seroprevalence of LB is well characterized in several European areas, there are no studies on the seroprevalence of LB before the description of the infection in the late 1970s.MethodsWe used a subset of historical serum samples (n = 994) collected during the Finnish Mobile Clinic Health Survey, a nationwide cross-sectional health survey of the 1960s and 1970s. All samples were screened with Borrelia burgdorferi whole-cell sonicate IgG ELISA. The seropositivity of the samples was further confirmed by the C6 peptide ELISA and recomBead IgG 2.0 bead immunoassay. The association of LB seropositivity with risk factors and with self-reported diseases and symptoms relating to disseminated LB were analysed by logistic regression.ResultsB. burgdorferi IgGs were detected in 199 of 994 analysed samples; hence, the overall seroprevalence was 20.0% (95% confidence interval: 17.6–22.6). The highest seroprevalence was observed in persons aged ≥50 years (165/696), in those currently not working (92/383), and in the regions of South and Central Finland (91/226 and 27/88, respectively). Further, perception of feeling unhealthy (129/197 versus 412/794) was higher among LB-seropositive individuals compared to LB-seronegative participants.ConclusionLB seroprevalence was considerably higher in Finland in the late 1960s and early 1970s than in 2011. This result questions the perception of an unprecedentedly high LB seroprevalence in present-day Europe