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.
An estimated 293,300 healthcare-associated cases of Clostridium difficile infection (CDI) occur annually in the United States. To date, research has focused on developing risk prediction models for CDI that work well across institutions. However, this one-size-fits-all approach ignores important hospital-specific factors. We focus on a generalizable method for building facility-specific models. We demonstrate the applicability of the approach using electronic health records (EHR) from the University of Michigan Hospitals (UM) and the Massachusetts General Hospital (MGH).
We utilized EHR data from 191,014 adult admissions to UM and 65,718 adult admissions to MGH. We extracted patient demographics, admission details, patient history, and daily hospitalization details, resulting in 4,836 features from patients at UM and 1,837 from patients at MGH. We used L2 regularized logistic regression to learn the models, and we measured the discriminative performance of the models on held-out data from each hospital.
Using the UM and MGH test data, the models achieved area under the receiver operating characteristic curve (AUROC) values of 0.82 (95% confidence interval [CI], 0.80–0.84) and 0.75 ( 95% CI, 0.73–0.78), respectively. Some predictive factors were shared between the 2 models, but many of the top predictive factors differed between facilities.
A data-driven approach to building models for estimating daily patient risk for CDI was used to build institution-specific models at 2 large hospitals with different patient populations and EHR systems. In contrast to traditional approaches that focus on developing models that apply across hospitals, our generalizable approach yields risk-stratification models tailored to an institution. These hospital-specific models allow for earlier and more accurate identification of high-risk patients and better targeting of infection prevention strategies.
The present study aimed to evaluate the precision, ease of use and likelihood of future use of portion size estimation aids (PSEA).
A range of PSEA were used to estimate the serving sizes of a range of commonly eaten foods and rated for ease of use and likelihood of future usage.
For each food, participants selected their preferred PSEA from a range of options including: quantities and measures; reference objects; measuring; and indicators on food packets. These PSEA were used to serve out various foods (e.g. liquid, amorphous, and composite dishes). Ease of use and likelihood of future use were noted. The foods were weighed to determine the precision of each PSEA.
Males and females aged 18–64 years (n 120).
The quantities and measures were the most precise PSEA (lowest range of weights for estimated portion sizes). However, participants preferred household measures (e.g. 200 ml disposable cup) – deemed easy to use (median rating of 5), likely to use again in future (all scored either 4 or 5 on a scale from 1=‘not very likely’ to 5=‘very likely to use again’) and precise (narrow range of weights for estimated portion sizes). The majority indicated they would most likely use the PSEA preparing a meal (94 %), particularly dinner (86 %) in the home (89 %; all P<0·001) for amorphous grain foods.
Household measures may be precise, easy to use and acceptable aids for estimating the appropriate portion size of amorphous grain foods.
The present analysis aimed to investigate the changes in the reported portion sizes (PS) of foods and beverages commonly consumed by Irish adults (18–64 years) from the North South Ireland Food Consumption Survey (NSIFCS) (1997–2001) and the National Adult Nutrition Survey (NANS) (2008–10). Food PS, which are defined as the weight of food (g) consumed per eating occasion, were calculated for comparable foods and beverages in two nationally representative cross-sectional Irish food consumption surveys and were published in NSIFCS and NANS. Repeated measure mixed model analysis compared reported food PS at the total population level as well as subdivided by sex, age, BMI and social class. A total of thirteen commonly consumed foods were examined. The analysis demonstrated that PS significantly increased for five foods (‘white sliced bread’, ‘brown/wholemeal breads’, ‘all meat, cooked’, ‘poultry, roasted’ and ‘milk’), significantly decreased for three (‘potatoes’, ‘chips/wedges’ and ‘ham, sliced’) and did not significantly change for five foods (‘processed potato products’, ‘bacon/ham’, ‘cheese’, ‘yogurt’ and ‘butter/spreads’) between the NSIFCS and the NANS. The present study demonstrates that there was considerable variation in the trends in reported food PS over this period.
This study aimed to determine whether patients with post-traumatic stress disorder (PTSD) show difficulty in recruitment of the regions of the frontal and parietal cortex implicated in top-down attentional control in the presence and absence of emotional distracters.
Unmedicated individuals with PTSD (n = 14), and age-, IQ- and gender-matched individuals exposed to trauma (n = 15) and healthy controls (n = 19) were tested on the affective number Stroop task. In addition, blood oxygen level-dependent responses, as measured via functional magnetic resonance imaging, were recorded.
Patients with PTSD showed disrupted recruitment of lateral regions of the superior and inferior frontal cortex as well as the parietal cortex in the presence of negative distracters. Trauma-comparison individuals showed indications of a heightened ability to recruit fronto-parietal regions implicated in top-down attentional control across distracter conditions.
These results are consistent with suggestions that emotional responsiveness can interfere with the recruitment of regions implicated in top-down attentional control; the heightened emotional responding of patients with PTSD may lead to the heightened interference in the recruitment of these regions.
Since the early 1990s, our understanding of plate boundary zone crustal deformation has been revolutionized by advances in global positioning system (GPS) techniques. These allow us to track directly the movement of the ground in real time, quantify the rates of crustal deformation within plate boundary zones and determine the displacement of the Earth's surface during earthquakes. The GPS measurements are taken at survey points permanently attached to the ground either by intermittent (survey-style) or continuous (daily, automated) collection of phase and pseudorange data from the constellation of GPS satellites that orbit the Earth. The GPS measurements spanning some period of time (usually longer than one year) can accurately track the movement of one point on the Earth's surface relative to others (to within a few mma−1 uncertainty). Such measurements have allowed scientists to determine where and how much tectonic strain is currently accumulating within plate boundary zones (e.g. Kreemer et al., 2000; McClusky et al., 2000; Sagiya et al., 2000; Beavan and Haines, 2001).
One of the major issues facing siting of nuclear facilities is the possibility of rapid seismic or slow aseismic strain at or near the facility. Elevated strain within a site (possibly due to a seismic event) could perturb a nuclear facility and/or jeopardize the long-term isolation of a high-level waste (HLW) repository in numerous ways, including activation/formation of faults, enhanced creep deformation of engineered barriers, flexural folding of the host rock or enhanced groundwater flow. Geological and seismological data are commonly used to assess future seismic shaking and rock deformation hazards for nuclear facilities (Stepp et al., 2001).
The processes that led to the onset and evolution of the North Atlantic Igneous Province (NAIP) have been a theme of debate in the past decades. A popular theory has been that the impingement on the lower lithosphere of a hot mantle plume (the ‘Ancestral Iceland’ plume) initiated the first voluminous outbursts of lava and initiated rifting in the North Atlantic area in Early Palaeogene times. Here we review previous studies in order to set the NAIP magmatism in a time–space context. We suggest that global plate reorganizations and lithospheric extension across old orogenic fronts and/or suture zones, aided by other processes in the mantle (e.g. local or regional scale upwellings prior to and during the final Early Eocene rifting), played a role in the generation of the igneous products recorded in the NAIP for this period. These events gave rise to the extensive Paleocene and Eocene igneous rocks in W Greenland, NW Britain and at the conjugate E Greenland–NW European margins. Many of the relatively large magmatic centres of the NAIP were associated with transient and geographically confined doming in Early Paleocene times prior to the final break-up of the North Atlantic area.
The literature contains considerable disagreements on the relative stabilities of the members of the copper hydroxyl sulphate family. Titration of copper sulphate with sodium hydroxide is claimed by some to produce only brochantite, while other reports indicate that antlerite and a dihydrate of antlerite are produced in the titration. Most stability field diagrams show that antlerite is the more stable stoichiomer at pH 4 and sulphate activity of 0.05–1. We have reexamined this stoichiometric family by titration of aqueous copper sulphate with sodiumhydroxide and sodium carbonate, reverse titration of sodiumhydroxide with copper sulphate and simultaneous addition of copper sulphate and sodium hydroxide at a variety of mole ratios, concentrations, temperatures and reaction times. We have also explored the reaction of copper hydroxide with copper sulphate and the reaction of weak bases, such as sodiumacetate, sodiumcarbonate and urea, with copper sulphate. Our work indicates that: (1) antlerite is not formed in reactions of 0.05 to 1.2 M CuSO4 with 0.05–1.0 M NaOH or Na2CO3 at room temperature; (2) antlerite is formed in the addition of small concentrations of base (≤0.01 M) to 1 M CuSO4 at 80°C, but not at roomtem perature or with 0.01 M CuSO4 at 80°C; (3) the formation of Cu5(SO4)2(OH)6·4H2O occurs at large Cu2+ to base mole ratios; (4) the compound described in the literature as antlerite dihydrate is actually Cu5(SO4)2(OH)6.4H2O; (5) at mole ratios of Cu2+ to OH– ranging from 2:1 to 1:2 the predominant product is brochantite; and (6) brochantite and Cu5(SO4)2(OH)6.4H2O are converted to antlerite in the presence of 1 M CuSO4 (the latter requires temperatures of 80°C or greater).
The Ksp (ion activity product) values of antlerite and brochantite were determined to be 2.53 (0.01)⨯10−48 and 1.01 (0.01)⨯10−69, respectively, using atomic absorption spectroscopy and Visual MINTEQ after equilibration in solutions of varying ionic strength and pH for six days. These values are in good agreement with those from the literature. However, after 6 months, antlerite in contact with solution is partially converted to brochantite and hence is metastable with a relatively low conversion rate. The Ksp value for antlerite must therefore be considered approximate. The relative stabilities of the copper hydroxyl sulphates are rationalized using appropriate equations and Gibbs energy calculations. A Gibbs free energy of formation for Cu5(SO4)2(OH)6.4H2O of –3442 kJ/mol was obtained from the simple salt approximation.
From a cognitive neuroscience perspective, the emotional attentional bias in post-traumatic stress disorder (PTSD) could be conceptualized either as emotional hyper-responsiveness or as reduced priming of task-relevant representations due to dysfunction in ‘top-down’ regulatory systems. We investigated these possibilities both with respect to threatening and positive stimuli among traumatized individuals with and without PTSD.
Twenty-two patients with PTSD, 21 trauma controls and 20 non-traumatized healthy participants were evaluated on two tasks. For one of these tasks, the affective Stroop task (aST), the emotional stimuli act as distracters and interfere with task performance. For the other, the emotional lexical decision task (eLDT), emotional information facilitates task performance.
Compared to trauma controls and healthy participants, patients with PTSD showed increased interference for negative but not positive distracters on the aST and increased emotional facilitation for negative words on the eLDT.
These findings document that hyper-responsiveness to threat but not to positive stimuli is specific for patients with PTSD.
There was a recent thread on the microscopy listserver by John McCaffrey (who hosted the discussion on TEM calibration at the 2001 M&M facility managers session) and Richard Beanland, dealing with the calibration of TEMs. This discussion was prompted by a calibration question from John Basgen, who was looking for more precision and more long-lived calibration specimens. The discussion complements and extends the one of the M&M 2001 managers meeting on EM calibration (Microscopy Today, January/February 2002, issue #02-1), and we are running this separately from that meeting discussion. (MT-ed.)
We present optical and microstructural characterization of nanocrystalline silicon superlattices (nc-Si SLs). Our samples have better than 5 % Si nanocrystal size distribution and a long range order along the direction of growth provided by periodically alternating layers of Si nanocrystals and SiO2. Flat and chemically abrupt nc-Si/SiO2 interfaces with a roughness of < 4Å are confirmed by transmission electron microscopy (TEM), Auger elemental microanalysis, X-ray small angle reflection, and low-frequency Raman scattering. Photoluminescence (PL) in our structures has been studied in details including time-resolved and steady-state PL spectroscopy in a wide range of temperature, excitation wavelength and power. Resonantly excited PL spectra show phonon steps proving that the PL originates in Si nanocrystals. Electrical measurements show signature of phonon-assisted tunneling proving low defect density nc-Si/SiO2 interface.
It has been observed that the sheet resistance of a Ti-salicided polysilicon-gate electrode or source/drain region increases significantly as the dimension reaches the lower sub-micron range. The resistance of platinum and nickel silicide (PtSi and NiSi), however, does not increase with reduced linewidth. We have studied PtSi and NiSi films with deep sub-micron linewidths on single crystal or poly-Si substrates. In this study, the material properties such as sheet resistance, grain structure and surface morphology of these silicide films in confined geometries are reviewed and compared with TiSi2. Process windows for forming and maintaining these silicides are explored.
PtSi/Si interfaces have been formed by depositing Pt layers on chemically cleaned, lightly doped, n-type Si (100) wafers in a UHV magnetron sputter-deposition system using ultra high purity Ar as the sputter gas, followed by ex-situ silicidation in N2 ambient utilizing a 3-step rapid thermal annealing (RTA) process. The polycrystalline PtSi layer, with oriented grains ranging in size from 50-100 nm, exhibits a columnar growth morphology. The PtSi/Si interface is planar with interface roughness in the order of 5 nm peak-to-peak. Auger depth profile shows uniform composition through the PtSi layer and a clean and chemically abrupt PtSi/Si interface.
Epitaxial PbTe and CdxPb1−xTe films have been grown on single crystal (111) BaF2 by low energy bias sputtering, and have been analyzed by transmission electron microscopy (TEM) and transmission electron diffraction (TED). Preparation of suitable cross-sectional TEM samples was made difficult by the tendency of the substrate to cleave apart during dimpling, and by the epoxy forming bridges across the sample during atom milling. Suitable preparation techniques were developed employing back-polishing the BaF2 substrates to <0.2 mm thickness, using a suitable epoxy, and shielding the argon atom beam during milling to prevent milling parallel to the surface. In cases where an epoxy bridge did form across the sample, the bridge was broken manually or by atom milling, depending upon the area of sample which was being investigated. These techniques are applicable to other materials which produce similar problems during TEM sample preparation.