To send content items to your account,
please confirm that you agree to abide by our usage policies.
If this is the first time you use this feature, you will be asked to authorise Cambridge Core to connect with your account.
Find out more about sending content to .
To send content items to your Kindle, first ensure email@example.com
is added to your Approved Personal Document E-mail List under your Personal Document Settings
on the Manage Your Content and Devices page of your Amazon account. Then enter the ‘name’ part
of your Kindle email address below.
Find out more about sending to your Kindle.
Note you can select to send to either the @free.kindle.com or @kindle.com variations.
‘@free.kindle.com’ emails are free but can only be sent to your device when it is connected to wi-fi.
‘@kindle.com’ emails can be delivered even when you are not connected to wi-fi, but note that service fees apply.
Introduction: For rhythm control of acute atrial fibrillation (AAF) in the emergency department (ED), choices include initial drug therapy or initial electrical cardioversion (ECV). We compared the strategies of pharmacological cardioversion followed by ECV if necessary (Drug-Shock), and ECV alone (Shock Only). Methods: We conducted a randomized, blinded, placebo-controlled trial (1:1 allocation) comparing two rhythm control strategies at 11 academic EDs. We included stable adult patients with AAF, where onset of symptoms was <48 hours. Patients underwent central web-based randomization stratified by site. The Drug-Shock group received an infusion of procainamide (15mg/kg over 30 minutes) followed 30 minutes later, if necessary, by ECV at 200 joules x 3 shocks. The Shock Only group received an infusion of saline followed, if necessary, by ECV x 3 shocks. The primary outcome was conversion to sinus rhythm for ≥30 minutes at any time following onset of infusion. Patients were followed for 14 days. The primary outcome was evaluated on an apriori-specified modified intention-to-treat (MITT) basis excluding patients who never received the study infusion (e.g. spontaneous conversion). Data were analyzed using chi-squared tests and logistic regression. Our target sample size was 374 evaluable patients. Results: Of 395 randomized patients, 18 were excluded from the MITT analysis; none were lost to follow-up. The Drug-Shock (N = 198) and Shock Only (N = 180) groups (total = 378) were similar for all characteristics including mean age (60.0 vs 59.5 yrs), duration of AAF (10.1 vs 10.8 hrs), previous AF (67.2% vs 68.3%), median CHADS2 score (0 vs 0), and mean initial heart rate (119.9 vs 118.0 bpm). More patients converted to normal sinus rhythm in the Drug-Shock group (97.0% vs 92.2%; absolute difference 4.8%, 95% CI 0.2-9.9; P = 0.04). The multivariable analyses confirmed the Drug-Shock strategy superiority (P = 0.04). There were no statistically significant differences for time to conversion (91.4 vs 85.4 minutes), total ED length of stay (7.1 vs 7.7 hours), disposition home (97.0% vs 96.1%), and stroke within 14 days (0 vs 0). Premature discontinuation of infusion was more common in the Drug-Shock group (8.1% vs 0.6%) but there were no serious adverse events. Conclusion: Both the Drug-Shock and Shock Only strategies were highly effective and safe in allowing AAF patients to go home in sinus rhythm. A strategy of initial cardioversion with procainamide was superior to a strategy of immediate ECV.
Important data in the investigation of laser-produced plasmas will be provided by studies of the X-ray emission characteristics in the range 1-10 keV, with time resolution comparable to plasma heating times. Present techniques using conventional photomultipliers or photodiodes are not suitable for time measurements on plasma heated by short optical pulses of several hundred picoseconds or less. The development of new X-ray cameras is also necessary. Their photocathodes must be chosen with care. In this paper we describe an initial study of the characteristics of metallic photocathodes: quantum efficiency, energy distribution of emitted photoelectrons, etc. Then we worked out the provisional sensitivity, spatial and temporal resolution of cameras in the streak mode or in shutter mode.
The SPICA mid- and far-infrared telescope will address fundamental issues in our understanding of star formation and ISM physics in galaxies. A particular hallmark of SPICA is the outstanding sensitivity enabled by the cold telescope, optimised detectors, and wide instantaneous bandwidth throughout the mid- and far-infrared. The spectroscopic, imaging, and polarimetric observations that SPICA will be able to collect will help in clarifying the complex physical mechanisms which underlie the baryon cycle of galaxies. In particular, (i) the access to a large suite of atomic and ionic fine-structure lines for large samples of galaxies will shed light on the origin of the observed spread in star-formation rates within and between galaxies, (ii) observations of HD rotational lines (out to ~10 Mpc) and fine structure lines such as [C ii] 158 μm (out to ~100 Mpc) will clarify the main reservoirs of interstellar matter in galaxies, including phases where CO does not emit, (iii) far-infrared spectroscopy of dust and ice features will address uncertainties in the mass and composition of dust in galaxies, and the contributions of supernovae to the interstellar dust budget will be quantified by photometry and monitoring of supernova remnants in nearby galaxies, (iv) observations of far-infrared cooling lines such as [O i] 63 μm from star-forming molecular clouds in our Galaxy will evaluate the importance of shocks to dissipate turbulent energy. The paper concludes with requirements for the telescope and instruments, and recommendations for the observing strategy.
Our current knowledge of star formation and accretion luminosity at high redshift (z > 3–4), as well as the possible connections between them, relies mostly on observations in the rest-frame ultraviolet, which are strongly affected by dust obscuration. Due to the lack of sensitivity of past and current infrared instrumentation, so far it has not been possible to get a glimpse into the early phases of the dust-obscured Universe. Among the next generation of infrared observatories, SPICA, observing in the 12–350 µm range, will be the only facility that can enable us to trace the evolution of the obscured star-formation rate and black-hole accretion rate densities over cosmic time, from the peak of their activity back to the reionisation epoch (i.e., 3 < z ≲ 6–7), where its predecessors had severe limitations. Here, we discuss the potential of photometric surveys performed with the SPICA mid-infrared instrument, enabled by the very low level of impact of dust obscuration in a band centred at 34 µm. These unique unbiased photometric surveys that SPICA will perform will fully characterise the evolution of AGNs and star-forming galaxies after reionisation.
A new uvby and Hβ monitoring program of low mass eclipsing binaries is currently being carried out in the framework of a 5 year observational program which also involves radial velocity determinations. The scope of this work is to provide very accurate absolute astrophysical parameters: mass, radius and effective temperatures, for main sequence late-type stars. One of the main goals is to improve the mass-luminosity relation in the low and intermediate mass range. A second objective is to perform accurate tests of the most recent grids of evolutionary models. This program is complementary to that currently being in progresss by the Copenhagen group.
In this contribution we present the photometric preliminary results obtained for three of the systems included in our long term survey: BH Vir, ZZ UMa and CR Cas for which, primary eclipses have been observed. Particular attention is paid to the determination of reddening, distances and radiative properties. A more detailed study will be carried out when the light curves and radial velocity measurements are completed
The objective of this study was to evaluate genetic and non-genetic factors influencing artificial insemination (AI) success in French dairy goats. Data analysis, on a total of 584 676 and 386 517 AI records for Alpine and Saanen breed, respectively, collected from 1992 to 2009, was conducted separately on each breed. We used a linear simple repeatability animal model which combined male and female random effect and environmental fixed effects. The most important environmental factor identified was the period within year effect due to the European heat wave of 2003. The estimated values of the annual fertility exhibited a negative trend of 1% loss of AI success per 10 years for Alpine breed only. The range of variation for the flock×within years random effect was 70% and 65% for Alpine and Saanen breeds. The negative effect on AI success of antibody production after repetitive hormonal treatment was confirmed. We observed an important positive relationship between fertility and protein yield expressed as quartile within flock×years of protein 250-day yield for female with lactation number over 1, while this trend was negative for primiparous females. We detected a negative effect of the duration of conservation of semen with a difference of about 4% of AI success between extreme values (2 to 8+ or 9+ years). Heritability estimates for male fertility were 0.0037 and 0.0043 for Alpine and Saanen breed respectively, while estimates for female fertility was 0.040 and 0.049. Repeatability estimates for males were 0.008 and 0.010 for Alpine and Saanen, respectively, and 0.097 and 0.102 for females. With such low values of heritability, selection can hardly affect fertility.
Clostridium difficile infection (CDI) has been extensively described in healthcare settings; however, risk factors associated with community-acquired (CA) CDI remain uncertain. This study aimed to synthesize the current evidence for an association between commonly prescribed medications and comorbidities with CA-CDI.
A systematic search was conducted in 5 electronic databases for epidemiologic studies that examined the association between the presence of comorbidities and exposure to medications with the risk of CA-CDI. Pooled odds ratios were estimated using 3 meta-analytic methods. Subgroup analyses by location of studies and by life stages were conducted.
Twelve publications (n=56,776 patients) met inclusion criteria. Antimicrobial (odds ratio, 6.18; 95% CI, 3.80–10.04) and corticosteroid (1.81; 1.15–2.84) exposure were associated with increased risk of CA-CDI. Among the comorbidities, inflammatory bowel disease (odds ratio, 3.72; 95% CI, 1.52–9.12), renal failure (2.64; 1.23–5.68), hematologic cancer (1.75; 1.02–5.68), and diabetes mellitus (1.15; 1.05–1.27) were associated with CA-CDI. By location, antimicrobial exposure was associated with a higher risk of CA-CDI in the United States, whereas proton-pump inhibitor exposure was associated with a higher risk in Europe. By life stages, the risk of CA-CDI associated with antimicrobial exposure greatly increased in adults older than 65 years.
Antimicrobial exposure was the strongest risk factor associated with CA-CDI. Further studies are required to investigate the risk of CA-CDI associated with medications commonly prescribed in the community. Patients with diarrhea who have inflammatory bowel disease, renal failure, hematologic cancer, or diabetes are appropriate populations for interventional studies of screening.
A number of studies have suggested that molecular materials could offer similar performance as, or even potentially supersede, those of inorganic materials in spintronics devices. Radically new spintronics functionalities, unavailable with conventional inorganic materials, could stem from the interface between ferromagnetic (FM) and molecular materials, giving rise to the so-called “spinterface” field. In this article, we review the fundamental concepts, recent experiments, and perspectives in this fast rising field, where the functionality is brought from the bulk to the ultimate downscaled device: the interface. The article shows how spin-dependent hybridization at the FM metal/molecule interface can lead to induced spin polarization in the molecular orbitals thanks to spin-dependent broadening and energy shifting of the molecular levels. Interfacial spin polarization can then be tailored thanks to chemical interactions. Examples of enhancement and reversal are given, and we highlight how this spin-dependent hybridization opens a new door for the spintronics crafting of multifunctionality through chemical designing and tuning on the molecular scale.
This study builds on existing research on the prevalence and consequences of mental illness discrimination by investigating and quantifying the relationships between experienced discrimination and costs of healthcare and leisure activities/social participation among secondary mental health service users in England.
We use data from the Mental Illness-Related Investigations on Discrimination (MIRIAD) study (n = 202) and a subsample of the Viewpoint study (n = 190). We examine experiences of discrimination due to mental illness in the domains of personal relationships, community activities, and health care, and how such experienced discrimination relates to patterns of service use and engagement in leisure activities.
Our findings show that the cost of health services used for individuals who reported previous experiences of discrimination in a healthcare setting was almost twice as high as for those who did not report any discrimination during the last 12 months (Relative Risk: 1.73; 95% Confidence Interval (CI): 1.39, 2.17) and this was maintained after controlling for symptoms and functioning. Experienced discrimination in healthcare (Relative Risk: 0.83; 95% CI: 0.81, 0.84) or in relationships (Relative Risk: 0.89; 95% CI: 0.87, 0.91), however, was associated with lower participation in, and hence lower costs of, leisure activities. Individuals who reported any discrimination in a healthcare setting had, on average, £434 higher costs associated with health service use while reported discrimination in the community was associated with increased leisure costs of £32.
These findings make an important initial step towards understanding the magnitude of the costs of mental health-related discrimination.
Pulsed-laser shadowgraphs and images of scattered light are combined with limiting and scattering data to build a model of the response of silicon napthalocyanine (SiNc) at concentrations on the order of 10−3 M in toluene to 12–16 ns 532 nm laser pulses over an energy range from 10 nJ to 2 mJ. The inherent spherical aberration induced by the sample has a profound effect on the response. The scattering is extremely intense above pulse energies of 100 μJ. The data indicates the response at pulse energies below 300 mJ is due to reverse saturable absorption. Full absorbance is not observed until the agglomerates vaporize. At fluences approaching 1 J/cm2 a plasma begins to form and the liquid near the window starts to boil. Intense scatter from the boiling liquid combined with plasma absorption produces hard clamping.
The deep ultraviolet (250 nm) photopatterning of spin-on films of polymeric Au mercaptide results in formation of adherent Au patterns. Fxcimer laser projection patterning and standard contact printing techniques give excellent pattern resolution on the micron scale. Laser direct write produces lines at very fast writing speeds. Exposed areas are less soluble than unexposed areas, i.e. the film behaves as a negative photoresist. Bakeout of developed patterns at 250°C yields good purity Au micropatterns up to 500 Å thick. Mechanistic information about pattern formation is gained from uv-visible, infrared, and mass spectrometric monitoring of the photolysis process, and from Auger analysis of films. Adherent patterns are apparently formed by photochemical cleavage of Au-S bonds followed by evaporation of a small amount of free mercaptide. The loss of ligand in the exposed areas renders them less soluble than unexposed film. Thermal decomposition of both photolyzed and unphotolyzed films has the same result of volatilizing all film material except Au.
Atomic transport due to electromigration in interconnect lines in integrated circuits depends strongly on temperature. Therefore temperature nonuniformities can create sites of atomic flux divergence resulting in material accumulation or depletion leading to failure. The mechanical stress which will evolve at the sites of material flux divergence will oppose the electromigration driving force. A model is developed to describe the stress evolution during electromigration in the presence of temperature nonuniformnities. Solutions of the differential equations describing the electromigration-induced stress buildup are calculated numerically. The solutions are compared to experimental data in the literature.
We present the results of experiments studying the effect of carrier depletion and interfacial stress on time to breakdown of'thin oxide films during constant current stressing High energy electrons resulting from carrier depletion conditions increase damage to oxides during tunneling. Carrier depletion conditions cause a dramatic decrease in time to breakdown and increase the number of early failures substantially. Mechanical interfacial stress results in a degradation in oxide reliability. Anode interfacial stress has been uniquely isolated from other phenomena such as cathode surface roughness, and has been shown to result in accelerated breakdown. These results have implications on oxide reliability and on test methodologies to obtain a measure of the same
It is known from literature that the properties of thin films greatly depend on their structuare. Therefore, the microstructural design is attractive for control over the properties of thin metal films used for interconnect metallization.
In this paper we discuss the potentialities of the self-ion assisted deposition technique for control over the grain and grain boundary structures of thin metal films and their properties such as resistivity and immunity to electromigration.
It was found that resistivity of aluminum films deposited at the 6 kV bias was virtually equal to resistivity of bulk aluminum. Films deposited at the less bias or without it had higher resistivities. Abnormal grain growth was found in 6 kV-films. In films prepared without bias normal grain growth proceeds.
Co-deposition of copper-palladium alloy films was demonstrated using low-pressure CVD from individual precursors - (hexafluoroacetylacetonato)copper(I)(vinyltrimethylsilane) [(hfac)Cu(I)vtms] and palladium(II)bis(hexafluoroacetylacetonate) [Pd(hfac)2], for Cu and Pd respectively. High-purity alloy films with controlled composition, microstructure and morphology were prepared and their oxidation behavior was examined at different temperatures and compared with that of pure copper CVD films with similar morphology. As-deposited copper-palladium alloy films showed improved resistance to oxidation up to 300°C in air. Enhanced oxidation resistance compared to Cu CVD films was observed at concentrations of palladium as low as 0.5 at. %.
Patterned 930 nm Al(1%-Si) interconnects over 147 nm of Cu were electromigration lifetime tested at 1.0–1.5 × 105 A/cm2 at 250 °C. The morphology of the surfaces of the electromigrated stripes with different line widths and times to failure were characterized by atomic force microscopy, and changes in surface roughness were compared. The diffusion of copper into the electromigrated aluminum stripes was determined by depth profiling using Auger electron spectroscopy. In particular, areas where hillocks formed were examined and compared to areas of median roughness.
In this paper, the impact of several front-end processing steps (up to gate oxidation) on gate oxide integrity (GOI) is evaluated. In PBL isolation processing, the use of as-deposited amorphous silicon (a-Si), subsequently annealed during nitride deposition, results in better structural and electrical properties compared to as-deposited polysilicon or as-deposited a-Si with an extra anneal step prior to nitride deposition. Thicker or dual sacrificial schemes exhibit improved gate oxide low voltage breakdown and charge-to-breakdown. Dilute RCA chemistries during pre-gate cleaning produce equal or better surfaces for gate oxidation than the conventional non-dilute RCA with less chemical usage. As gate oxides are scaled below 100Å, lowering gate oxidation temperature is proven to result in far better gate oxide quality than maintaining process temperatures at or above 900°C and diluting oxygen in either argon or nitrogen.
Electromigration-induced failure of near-bamboo interconnects depends strongly on the number and lengths of both polygranular clusters and bamboo segments in a line. We have used numerical techniques to calculate the stress profile as a function of position and time for near-bamboo lines with a variety of microstructures. Our results show that coupling of stress profiles between nearby clusters can affect the time to reach a pre-defined critical, or failure, stress. The degree of coupling depends both on the spacing between clusters and the ratio of the diffusivities between polygranular and single crystal regions. Electromigration failure is therefore sensitive to the distribution and lengths of bamboo segments, and the likelihood of long polygranular clusters coinciding with adjacent short bamboo segments.
Void and hillock formation during annealing was studied depending on the deposition conditions. Aluminum films were deposited onto oxidized silicon substrates by the self-ion assisted technique. The bias 0 or 6 kV was applied to the substrate during deposition. The films were then annealed in vacuum for 1 hour in the temperature range from 1500 to 550°C. The structure of the films was investigated by transmission electron microscopy.
It was found that recrystallization and void and hillock formation in the films depend on the bias during deposition. Normal grain growth occurred in the films deposited without bias. Abnormal grain growth was observed in the 6 kV-films. It was also found that the mechanism of stress relaxation during thermal cycling depends on the self-ion bombardment. In the films prepared without bias, stress relaxation proceeds by diffusion creep. In the films deposited at the 6 kV bias, stress relaxation proceeds by plastic deformation.