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We examined the prevalence and correlates of Helicobacter pylori (H. pylori) infection according to cytotoxin-associated gene A (CagA) phenotype, a main virulence antigen, among the ethnically diverse population groups of Jerusalem. A cross-sectional study was undertaken in Arab (N = 959) and Jewish (N = 692) adults, randomly selected from Israel's national population registry in age-sex and population strata. Sera were tested for H. pylori immunoglobulin G (IgG) antibodies. Positive samples were tested for virulence IgG antibodies to recombinant CagA protein, by enzyme-linked immunosorbent assay. Multinomial regression models were fitted to examine associations of sociodemographic factors with H. pylori phenotypes. H. pylori IgG antibody sero-prevalence was 83.3% (95% confidence interval (CI) 80.0%–85.5%) and 61.4% (95% CI 57.7%–65.0%) among Arabs and Jews, respectively. Among H. pylori positives, the respective CagA IgG antibody sero-positivity was 42.3% (95% CI 38.9%–45.8%) and 32.5% (95% CI 28.2%–37.1%). Among Jews, being born in the Former Soviet Union, the Middle East and North Africa, vs. Israel and the Americas, was positively associated with CagA sero-positivity. In both populations, sibship size was positively associated with both CagA positive and negative phenotypes; and education was inversely associated. In conclusion, CagA positive and negative infection had similar correlates, suggesting shared sources of these two H. pylori phenotypes.
Laser–solid interactions are highly suited as a potential source of high energy X-rays for nondestructive imaging. A bright, energetic X-ray pulse can be driven from a small source, making it ideal for high resolution X-ray radiography. By limiting the lateral dimensions of the target we are able to confine the region over which X-rays are produced, enabling imaging with enhanced resolution and contrast. Using constrained targets we demonstrate experimentally a
X-ray source, improving the image quality compared to unconstrained foil targets. Modelling demonstrates that a larger sheath field envelope around the perimeter of the constrained targets increases the proportion of electron current that recirculates through the target, driving a brighter source of X-rays.
The effect of male hierarchy on the sexual activity of individuals is unclear from the recent scientific literature and a clear distinction between the social and sexual aspects of this hierarchy is lacking. Moreover, the effect of male team size on the extent of sexual competition between individuals has not been examined in the recently developed group mating systems for pigs, such as the Dynamic Service System for gilts (DSS). The main objectives of the present study were therefore to examine the effect of boar sexual status on the sexual activity of individuals and the influence of boar team size on the reproductive output of a DSS.
The heat period at which gilts are bred affects first reproductive performance and overall sow productivity. However, most studies which have examined this subject have confounded chronological age (i.e. days) with physiological age (i.e. number of heat periods experienced) and the importance of each factor remains unclear. The Dynamic Service System (DSS) is a recently developed variant of group mating and the optimum heat period at which gilts should be bred has never been established. This study tested the hypothesis that the physiological age at which gilts are first mated in a DSS will affect their first reproductive behaviour (i.e. mating frequency and quality) and performance.
Introduction: Some low acuity Emergency Department (ED) presentations are considered non-urgent or convenience visits and potentially avoidable with improved access to primary care. This study explored self-reported reasons why non-urgent patients presented to the ED. Methods: Patients, 17 years and older, were randomly selected from electronic registration records at three urban EDs in Edmonton, Alberta (AB), Canada during weekdays (0700 to 1900). A 47-item questionnaire was completed by each consenting patient, which included items on whether the patient believed the ED was their best care option and the rationale supporting their response. A thematic content analysis was performed on the responses, using previous experience and review of the literature to identify themes. Results: Of the 2144 eligible patients, 1408 (65.7%) questionnaires were returned, and 1402 (65.4%) were analyzed. For patients who felt the ED was their best option (n = 1234, 89.3%), rationales included: safety concerns (n = 309), effectiveness of ED care (n = 284), patient-centeredness of ED (n = 277), and access to health care professionals in the ED (n = 204). For patients who felt the ED was not their best care option (n = 148, 10.7%), rationales included a perception that: access to health professionals outside the ED was preferable (n = 39), patient-centeredness (particularly timeliness) was lacking in the ED (n = 26), and their health concern was not important enough to require ED care (n = 18). Conclusion: Even during times when alternative care options are available, the majority of non-urgent patients perceived the ED to be the most appropriate location for care. These results highlight that simple triage scores do not accurately reflect the appropriateness of care and that understanding the diverse and multi-faceted reasons for ED presentation are necessary to implement strategies to support non-urgent, low acuity care needs.
Introduction: Some non-urgent/low-acuity Emergency Department (ED) presentations are considered convenience visits and potentially avoidable with improved access to primary care services. This study surveyed patients who presented to the ED and explored their self-reported reasons and barriers for not being connected to a primary care provider (PCP). Methods: Patients aged 17 years and older were randomly selected from electronic registration records at three urban EDs in Edmonton, Alberta (AB), Canada. Following initial triage, stabilization, and verbal informed consent, patients completed a 47-item questionnaire. Data from the survey were cross-referenced to a minimal patient dataset consisting of ED and demographic information. The questionnaire collected information on patient characteristics, their connection to a PCP, and patients' reasons for not having a PCP. Results: Of the 2144 eligible patients, 1408 (65.7%) surveys were returned and 1402 (65.4%) were completed. The majority of patients (74.4%) presenting to the ED reported having a family physician; however, the ‘closeness’ of the connection to their family physician varied greatly among ED patients with the most recent family physician visit ranging from 1 hour before ED presentation to 45 years prior. Approximately 25% of low acuity ED patients reported no connection with a family physician. Reasons for a lack of PCP connection included: prior physician retired, left, or died (19.8%), they had never tried to find one (19.2%), they had recently moved to Alberta (18.0%), and they were unable to find one (16.5%). Conclusion: A surprisingly high proportion of ED patients (25.6%) have no identified PCP. Patients had a variety of reasons for not having a family physician. These need to be understood and addressed in order for primary care access to successfully contribute to diverting non-urgent, low acuity presentations from the ED.
Previous research in post-traumatic stress disorder (PTSD) has identified disrupted ventromedial prefrontal cortex (vmPFC) function in those with v. without PTSD. It is unclear whether this brain region is uniformly affected in all individuals with PTSD, or whether vmPFC dysfunction is related to individual differences in discrete features of this heterogeneous disorder.
In a sample of 51 male veterans of Operation Enduring Freedom/Operation Iraqi Freedom, we collected functional magnetic resonance imaging data during a novel threat anticipation task with crossed factors of threat condition and temporal unpredictability. Voxelwise regression analyses related anticipatory brain activation to individual differences in overall PTSD symptom severity, as well as individual differences in discrete symptom subscales (re-experiencing, emotional numbing/avoidance, and hyperarousal).
The vmPFC showed greater anticipatory responses for safety relative to threat, driven primarily by deactivation during threat anticipation. During unpredictable threat anticipation, increased PTSD symptoms were associated with relatively greater activation for threat v. safety. However, simultaneous regression on individual symptom subscales demonstrated that this effect was driven specifically by individual differences in hyperarousal symptoms. Furthermore, this analysis revealed an additional, anatomically distinct region of the vmPFC in which re-experiencing symptoms were associated with greater activation during threat anticipation.
Increased anticipatory responses to unpredictable threat in distinct vmPFC subregions were uniquely associated with elevated hyperarousal and re-experiencing symptoms in combat veterans. These results underscore the disruptive impact of uncertainty for veterans, and suggest that investigating individual differences in discrete aspects of PTSD may advance our understanding of underlying neurobiological mechanisms.
The excavations of the cemetery groups at Balneaves, Loanleven and Park of Tongland facilitate an examination of many aspects of Bronze Age burial practices in Scotland. They are notable as much for the differences in burial ritual they imply as for the very narrow chronological period in which they were used. The three sites produced a total of seventeen 14C dates, two of which are aberrant, with means of the remaining fifteen falling within a period of 250 years (3370–3610 bp in radiocarbon years). The excavations were sponsored by Historic Scotland (formerly Historic Buildings and Monuments, Scotland).
At Balneaves, a penannular ditch enclosed sixteen features, including a group of seven pits with cremation burials, four of which were associated with a distinctive assemblage of collared urns. The cremated bone was well preserved. At least one large standing stone had been erected on the site, and this was buried in the medieval period.
At Loanleven, only a segment of the enclosing ring-ditch survived, within which were four cists, two containing inhumations and two cremations, one of the latter (Cist 2) associated with a fragment of a food vessel. A decorated slab, in so-called ‘Passage Grave Style’, was recovered from Cist 1, and the same cist produced palynological evidence for grave furnishings in the form of a mat of plant material which probably underlay the body. 14C dates give a terminus ante quem of 3620±50 bp (GU–2543) for the re-use of the decorated slab, and a terminus post quem of 3410±50 bp (GU–2542) for the food vessel grave.
Park of Tongland, regarded as a Four-Poster stone circle, was excavated after the fall of a standing stone. It was shown to be of multi-period construction, consisting of a cairn which overlay seven pits containing fragmentary cremation burials, two associated with collared urns. The standing stones may not all have been erect at the same time. A series of 14C dates fell within the range of 1480–1530 bc.
The experimental mechanics of microelectronics components requires high spatial resolution measurements that are best obtained by using the scanning microscope because of the high spacial resolution and depth of field obtained using this instrument. This paper describes how measurements made from photographs taken in the scanning electron microscope have been used successfully to determine the strains which develop due to differences in coefficient of thermal between various parts of microelectronic components. Results are presented for thermal strains in the solder joints of a surface mounted component and in a printed circuit board plated through hole.
Auger electron analysis of oxides grown at 573 K in dried oxygen on the matrix and on precipitates in a 0.5 wt% Ni in zirconium alloy, is part of a larger program to study the effect of second phase particles on the oxidation and hydriding behaviour of Zircaloy-2. The alloy consisted of a zirconium matrix containing randomly distributed Zr2Ni precipitates of up to 10 μM in diameter. Oxidation simultaneously proceeded about the whole periphery of the precipitate and after approximately 50 days exposure was completely oxidized and of nearly uniform composition. The chemical structure of the oxides grown on the matrix and on the free and internal surfaces of the precipitate were determined as a function of depth in the oxide film.
The continuing shrinkage of feature size and environmental concerns regarding the use of lead containing solder are major driving forces in the search for alternative technologies for metal interconnects in electronic packaging. Electrically conductive adhesives are considered a potential substitute for the lead-tin solder. This study concentrated on interfacial properties of eutectic solder and silver-filled epoxy adhesives. A freeze fracture technique was employed in order to preserve interfacial information. The chemical composition of the fractured faces varied; the adhesive side was rich in tin, whereas the eutectic solder side showed lead-rich characteristics.
It is known that aluminum will readily form aluminum hydroxide during aqueous exposures. Thick oxide layers with a typical pseudoboehmite (fibre-like network) structure and bayerite crystals were observed on the aluminum metallization after the aqueous cleaning process. The study investigated the effect of a deionized (DI) water cleaning process (recently implemented to replace CFC-based cleaning technology) on the surface chemistry and corrosion behaviour of aluminum wire bond pads. The study also correlated the wire bond yield and oxide thickness with various water cleaning process parameters. The wire bond yield and reliability issues are discussed briefly.
Future planetary exploration missions will require safe and precision soft-landing to target scientifically interesting sites near hazardous terrain features, such as escarpments, craters, slopes, and rocks. Although the landing accuracy has steadily improved over time to approximately 35 km for the recent Mars Exploration Rovers due to better approach navigation, a drastically different guidance, navigation and control concept is required to meet future mission requirements. For example, future rovers will require better than 6 km landing accuracy for Mars and better than 1 km for the Moon plus 100 m maneuvering capability to avoid hazards. Laser Radar or Lidar technology can be the key to meeting these objectives since it can provide highresolution 3-D maps of the terrain, accurately measure ground proximity and velocity, and determine atmospheric pressure and wind velocity. These lidar capabilities can enable the landers of the future to identify the pre-selected landing zone and hazardous terrain features within it, determine the optimum flight path, having atmospheric pressure and winds data, and accurately navigate using precision ground proximity and velocity data. This paper examines the potential of lidar technology in future human and robotic missions to the Moon, Mars, and other planetary bodies. A guidance and navigation control architecture concept utilizing lidar sensors will be presented and its operation will be described. The performance and physical requirements of the lidar sensors will be also discussed.
Diffuse elastic scattering of electrons by single nanometer-sized defects in ion irradiated Au has been measured quantitatively. Results are given for two dislocation loops and compared with published calculations to establish the loop geometry and interstitial or vacancy nature. Defect images using only diffuse scatttering are achieved with high sensitivity and good resolution by a hollow-cone dark-field method.
This article focuses on mental health assessment of refugees in clinical, educational and administrative-legal settings in order to synthesise research and practice designed to enhance and promote further development of culturally appropriate clinical assessment services during the refugee resettlement process. It specifically surveys research published over the last 25 years into the development, reliability measurement and validity testing of assessment instruments, which have been used with children, adolescents and adults from refugee backgrounds, prior to or following their arrival in a resettlement country, to determine whether the instruments meet established crosscultural standards of conceptual, functional, linguistic, technical and normative equivalence. The findings suggest that, although attempts have been made to develop internally reliable, appropriately normed tests for use with refugees from diverse cultural and linguistic backgrounds, matters of conceptual and linguistic equivalence and test–retest reliability are often overlooked. Implications of these oversights for underreporting refugees' mental health needs are considered. Efforts should also be directed towards development of culturally comparable, valid and reliable measures of refugee children's mental health and of refugee children's and adults' psychoeducational, neuropsychological and applied memory capabilities.
Equilibrium properties of linear theta-pinch plasmas are studied within the framework of the steady-state (∂ / ∂ t = 0) Vlasov– Maxwell equations. The analysis is carried out for an infinitely long plasma column aligned parallel to an externally applied axial magnetic field Bzext ê 2. Equilibrium properties are calculated for the class of rigid-rotor Vlasov equilibria, in which the jth component distribution function f j(H⊥, Pθ, υ 2) depends on perpendicular energy H⊥ and canonical angular momentum Pθ, exclusively through the linear combination H⊥ – ω jPθ, where ω j = const. = angular velocity of mean rotation. General equilibrium relations that pertain to the entire class of rigid-rotor Vlasov equilibria are discussed; and specific examples of sharp- and diffuse-boundary equilibrium configurations are considered. Rigid-rotor density and magnetic field profiles are compared with experimentally observed profiles. A general prescription is given for determining the functional dependence of the equilibrium distribution function on H⊥−ωjPθg in circumstances, where the density profile or magnetic field profile is specified.
This paper discusses the procedure for constructing intense hollow relativistic electron beam equilibria within the framework of the steady-state (∂/∂t = 0) Vlasov–Maxwell equations. It is assumed that the electron beam propagates parallel to a uniform axial guide field Bext0 = B0 êz inside a grounded cylindrical conductor, and that the positive ions provide a partially neutralizing background with density n0i(r) = fn0e(r), where f = const. = fractional neutralization. The equilibrium properties are calculated for the specific choice of electron distribution function , where H, Pθ, and Pz are the energy, canonical angular momentum, and axialcanonical momentum, respectively, for an electron moving in the equilibrium fields, and , and P0 are constants. For this choice of distribution function, the mean axial velocity of the electron beam is equal to , and the beam density profile is hollow with inner and outer radii, R0 and R1, determined self-consistently from nonlinear boundary conditions that involve the equilibrium parameters Po, γb, γ0, etc., and the equilibrium self fields. Closed expressions for Ro and B1 are obtained for the case where the collisionless skin depth c/ωpe is large in comparison with the characteristic radius of the electron beam, and the beam density is sufficiently low that . The two cases, Po>0 and Po<0, are considered.