Difference frequency generation by quasi-phase matching in periodically intermixed semiconductor superlattice waveguides

Wavelength conversion by difference frequency generation is demonstrated in domain-disordered quasi-phase-matched waveguides. The waveguide structure consisted of a GaAs/AlGaAs superlattice core that was periodically intermixed by ion implantation. For quasi-phase-matching periods of 3.0–3.8 μm, degeneracy pump wavelengths were found by second-harmonic generation experiments for fundamental wavelengths between 1520 and 1620 nm in both type-I and type-II configurations. In the difference frequency generation experiments, output powers up to 8.7 nW were generated for the type-I phase matching interaction and 1.9 nW for the type-II interaction. The conversion bandwidth was measured to be over 100 nm covering the C, L, and U optical communications bands, which agrees with predictions

Investigation of the origin of shallow gas in outer Moray Firth open blocks 15/20c and 15/25d

This report briefly describes the evidence for the origin of shallow gas in Outer Moray Firth open blocks 15/20c and 15/25d. Sea floor pockmarks are known to occur within these blocks, and they indicate the seepage of gas from shallow levels into the local water column. An environmental concern is that any industry activity in these blocks must not plumb into any component of the system that is sustaining the gas seepages at sea bed. The conclusions of this study are: 1. Interpretation of the available BGS shallow seismic data and commercial site investigation data shows that gas is seeping from sea bed in three large active pockmark complexes in approximately 150 m or more water depth: the Challenger Pockmark Complex in the north of block 15/25d, the Scanner Pockmark Complex in the south of block 15/25d and the Scotia Pockmark which is adjacent to the north-east of the Scanner Pockmark Complex. 2. A review of the peer-reviewed scientific publications indicates that the majority of the arguments based on isotope analyses of gas and authigenic carbonate are for a predominantly biological origin for the gas seeping from the active pockmarks. However, biogenic isotopic signatures in the Gulf of Mexico and the North Sea are thought to have been generated when thermogenic hydrocarbons in shallow sediments were re-cycled by bacteria to produce ‘secondary’ methane with an identical isotopic signature to biogenic methane. Thus, the isotopic data derived from the Scanner Pockmark Complex do not provide a secure basis for determining whether the gas escaping from the pockmarks in block 15/25 is primarily biogenic or thermogenic in origin. 3. Interpretations completed during this project indicate that gas seeping to sea bed in the largest pockmarks is reservoired within the uppermost part of the Aberdeen Ground Formation, where it is preserved between buried sub-glacial channels. The gas seepages at sea bed are fed from an almost continuous blanket of buried gas-charged sediments situated between the sub-glacial channel margins at approximately 280-300 ms two-way time (around 120 m below sea bed) in the northern part of block 15/25d. 4. An empirical conclusion from distribution patterns observed in the interval between sea bed and 400 ms two-way time is that loss of shallow gas from the gas-charged interval at approximately 280-300ms two-way time will cut off the supply of shallow gas to the active pockmarks. Dry well 15/25b-1A, located immediately to the north of the Scanner Pockmark Complex, appears to have been drilled on the margin of the shallow gas reservoir. A recommendation is that future development operations should not disturb the shallow gas reservoir. 5. All of the hydrocarbon discoveries made within and around the study area are oil. The nearest Upper Jurassic Kimmeridge Clay Formation principal thermogenic gas kitchen lies some 30 km to the south-east, in the Fisher Bank Basin. Gas has been proved to have migrated up into Mid-Eocene sandstones (e.g. Alba Field) in that basin. Although it is possible that further vertical migration might have been achieved through minor faults and fractures in the Late Eocene to Pliocene, no evidence was observed in the 3D data to connect the location of the active pockmarks with supply from the thermogenic gas kitchen. For example, no gas chimneys have been observed within the Tertiary section on 3D seismic data across the study area.. Although no major faults have been found in 3D seismic data that transect the entire Eocene to Pliocene interval, minor polygonal faulting has been observed within the upper part of the Hordaland Group

Relationship between lung function and grip strength in older hospitalized patients: a pilot study.

OBJECTIVE: Older people with reduced respiratory muscle strength may be misclassified as having COPD on the basis of spirometric results. We aimed to evaluate the relationship between lung function and grip strength in older hospitalized patients without known airways disease. METHODS: Patients in acute medical wards were recruited who were aged ≥70 years; no history, symptoms, or signs of respiratory disease; Mini Mental State Examination ≥24; willing and able to consent to participate; and able to perform hand grip and forced spirometry. Data including lung function (forced expiratory volume in 1 second [FEV1], forced vital capacity [FVC], FEV1/FVC, peak expiratory flow rate [PEFR], and slow vital capacity [SVC]), grip strength, age, weight, and height were recorded. Data were analyzed using descriptive statistics and linear regression unadjusted and adjusted (for age, height, and weight). RESULTS: A total of 50 patients (20 men) were recruited. Stronger grip strength in men was significantly associated with greater FEV1, but this was attenuated by adjustment for age, height, and weight. Significant positive associations were found in women between grip strength and both PEFR and SVC, both of which remained robust to adjustment. CONCLUSION: The association between grip strength and PEFR and SVC may reflect stronger patients generating higher intrathoracic pressure at the start of spirometry and pushing harder against thoracic cage recoil at end-expiration. Conversely, patients with weaker grip strength had lower PEFR and SVC. These patients may be misclassified as having COPD on the basis of spirometric results

Influence of implant diameter on surrounding bone

Objectives : Implant osseointegration is dependent upon various factors, such as bone quality and type of implant surface. It is also subject to adaptation in response to changes in bone metabolism or transmission of masticatory forces. Understanding of long-term physiologic adjustment is critical to prevention of potential loss of osseointegration, especially because excessive occlusal forces lead to failure. To address this issue, wide-diameter implants were introduced in part with the hope that greater total implant surface would offer mechanical resistance. Yet, there is little evidence that variation in diameter translates into a different bone response in the implant vicinity. Therefore, this study aimed at comparing the impact of implant diameter on surrounding bone. Material and methods : Twenty standard (3.75 mm) and 20 wide (5 mm) implants were placed using an animal model. Histomorphometry was performed to establish initial bone density (IBD), bone to implant contact (BIC) and adjacent bone density (ABD). Results : BIC was 71% and 73%, whereas ABD was 65% and 52%, for standard and wide implants, respectively. These differences were not statistically different ( P >0.05). Correlation with IBD was then investigated. BIC was not correlated with IBD. ABD was not correlated to IBD for standard implants ( r 2 =0.126), but it was correlated with wide implants ( r 2 =0.82). In addition, a 1 : 1 ratio between IBD and ABD was found for wide implants. It can be concluded, within the limits of this study, that ABD may be influenced by implant diameter, perhaps due to differences in force dissipation. To cite this article: Brink J, Meraw SJ, Sarment DP. Influence of implant diameter on surrounding bone. Clin. Oral Impl. Res. 18 , 2007; 563–568 doi: 10.1111/j.1600-0501.2007.01283.xPeer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/75089/1/j.1600-0501.2007.01283.x.pd

Prevalence and characterization of human mecC methicillin-resistant Staphylococcus aureus isolates in England

Objectives: There are limited data available on the epidemiology and prevalence of methicillin-resistant Staphylococcus aureus (MRSA) in the human population that encode the recently described mecA homologue, mecC. To address this knowledge gap we undertook a prospective prevalence study in England to determine the prevalence of mecC among MRSA isolates.<p></p> Patients and methods: Three hundred and thirty-five sequential MRSA isolates from individual patients were collected from each of six clinical microbiology laboratories in England during 2011–12. These were tested by PCR or genome sequencing to differentiate those encoding mecA and mecC. mecC-positive isolates were further characterized by multilocus sequence typing, spa typing, antimicrobial susceptibility profile and detection of PBP2a using commercially available kits.<p></p> Results: Nine out of the 2010 MRSA isolates tested were mecC positive, indicating a prevalence among MRSA in England of 0.45% (95% CI 0.24%–0.85%). The remainder were mecA positive. Eight out of these nine mecC MRSA isolates belonged to clonal complex 130, the other being sequence type 425. Resistance to non-β-lactam antibiotics was rare among these mecC MRSA isolates and all were phenotypically identified as MRSA using oxacillin and cefoxitin according to BSAC disc diffusion methodology. However, all nine mecC isolates gave a negative result using three different commercial PBP2a detection assays. Conclusions: mecC MRSA are currently rare among MRSA isolated from humans in England and this study provides an important baseline prevalence rate to monitor future changes, which may be important given the increasing prevalence of mecC MRSA reported in Denmark.<p></p&gt

Young people's uses of celebrity: Class, gender and 'improper' celebrity

This is an Author's Accepted Manuscript of an article published in Discourse: Studies in the Cultural Politics of Education, 34(1), 2013, copyright Taylor & Francis, available online at: http://www.tandfonline.com/10.1080/01596306.2012.698865.In this article, we explore the question of how celebrity operates in young people's everyday lives, thus contributing to the urgent need to address celebrity's social function. Drawing on data from three studies in England on young people's perspectives on their educational and work futures, we show how celebrity operates as a classed and gendered discursive device within young people's identity work. We illustrate how young people draw upon class and gender distinctions that circulate within celebrity discourses (proper/improper, deserving/undeserving, talented/talentless and respectable/tacky) as they construct their own identities in relation to notions of work, aspiration and achievement. We argue that these distinctions operate as part of neoliberal demands to produce oneself as a ‘subject of value’. However, some participants produced readings that show ambivalence and even resistance to these dominant discourses. Young people's responses to celebrity are shown to relate to their own class and gender position.The Arts and Humanities Research Council, the British Academy, the Economic and Social Research Council, and the UK Resource Centre for Women in Science Engineering and Technology

Switching model with two habitats and a predator involving group defence

Switching model with one predator and two prey species is considered. The prey species have the ability of group defence. Therefore, the predator will be attracted towards that habitat where prey are less in number. The stability analysis is carried out for two equilibrium values. The theoretical results are compared with the numerical results for a set of values. The Hopf bifuracation analysis is done to support the stability results

Apodization technique for fiber grating fabrication with a halftone transmission amplitude mask

Experimental results of fiber Bragg gratings fabricated with halftone amplitude transmission masks and 10-cm-long phase masks are presented for the first time to our knowledge. The performance of the devices is evaluated in terms of their spectral characteristics and deviation from linear group delay. Good out-of-band sidelobe suppression of -27 dB and group-delay ripple of ?9.5 ps is achieved for fully apodized grating devices

The rationale for heart team decision-making for patients with stable, complex coronary artery disease

Stable complex coronary artery disease can be treated with coronary artery bypass grafting (CABG), percutaneous coronary intervention (PCI), or medical therapy. Multidisciplinary decision-making has gained more emphasis over the recent years to select the most optimal treatment strategy for individual patients with stable complex coronary artery disease. However, the so-called 'Heart Team' concept has not been widely implemented. Yet, decision-making has shown to remain suboptimal; there is large variability in PCI-to-CABG ratios, which may predominantly be the consequence of physician-related factors that have raised concerns regarding overuse, underuse, and inappropriate selection of revascularization. In this review, we summarize these and additional data to support the statement that a multidisciplinary Heart Team consisting of at least a clinical/non-invasive cardiologist, interventional cardiologist, and cardiac surgeon, can together better analyse and interpret the available diagnostic evidence, put into context the clinical condition of the patient as well as consider individual preference and local expertise, and through shared decision-making with the patient can arrive at a most optimal joint treatment strategy recommendation for patients with stable co