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Salmonella spp. continue to be a leading cause of foodborne morbidity worldwide. To assess the risk of foodborne disease, current national regulatory schemes focus on prevalence estimates of Salmonella and other pathogens. The role of pathogen quantification as a risk management measure and its impact on public health is not well understood. To address this information gap, a quantitative risk assessment model was developed to evaluate the impact of pathogen enumeration strategies on public health after consumption of contaminated ground turkey in the USA. Public health impact was evaluated by using several dose–response models for high- and low-virulent strains to account for potential under- or overestimation of human health impacts. The model predicted 2705–21 099 illnesses that would result in 93–727 reported cases of salmonellosis. Sensitivity analysis predicted cooking an unthawed product at home as the riskiest consumption scenario and microbial concentration the most influential input on the incidence of human illnesses. Model results indicated that removing ground turkey lots exceeding contamination levels of 1 MPN/g and 1 MPN in 25 g would decrease the median number of illnesses by 86–94% and 99%, respectively. For a single production lot, contamination levels higher than 1 MPN/g would be needed to result in a reported case to public health officials. At contamination levels of 10 MPN/g, there would be a 13% chance of detecting an outbreak, and at 100 MPN/g, the likelihood of detecting an outbreak increases to 41%. Based on these model prediction results, risk management strategies should incorporate pathogen enumeration. This would have a direct impact on illness incidence linking public health outcomes with measurable food safety objectives.
Recent efforts to characterize the nanoscale structural and chemical modifications induced by energetic ion irradiation in nuclear materials have greatly benefited from the application of synchrotron-based x-ray diffraction (XRD) and x-ray absorption spectroscopy (XAS) techniques. Key to the study of actinide-bearing materials has been the use of small sample volumes, which are particularly advantageous, as the small quantities minimize the level of radiation exposure at the ion-beam and synchrotron user facility. This approach utilizes energetic heavy ions (energy range: 100 MeV–3 GeV) that pass completely through the sample thickness and deposit an almost constant energy per unit length along their trajectory. High energy x-rays (25–65 keV) from intense synchrotron light sources are then used in transmission geometry to analyze ion-induced structural and chemical modifications throughout the ion tracks. We describe in detail the experimental approach for utilizing synchrotron radiation (SR) to study the radiation response of a range of nuclear materials (e.g., ThO2 and Gd2TixZr2−xO7). Also addressed is the use of high-pressure techniques, such as the heatable diamond anvil cell, as a new means to expose irradiated materials to well-controlled high-temperature (up to 1000 °C) and/or high-pressure (up to 50 GPa) conditions. This is particularly useful for characterizing the annealing kinetics of irradiation-induced material modifications.
The prevalence of overweight and obesity is increasing worldwide. The impact of overweight on post-tonsillectomy haemorrhage rates in children and adults is unclear.
Body mass index and post-tonsillectomy haemorrhage were evaluated in all patients treated with tonsillectomy within one year in a tertiary referral centre. Bleeding episodes were categorised according to the Austrian Tonsil Study.
Between June 2011 and June 2012, 300 adults and children underwent tonsillectomy. Post-tonsillectomy haemorrhage occurred in 55 patients. Of those, 29 were type A (history of blood in saliva only, no active bleeding), 15 were type B (active bleeding, treatment under local anaesthesia) and 11 were type C (active bleeding, treatment under general anaesthesia). The return to operating theatre rate was 3.7 per cent. Post-tonsillectomy haemorrhage was more frequent in adolescents and adults than in children. Overweight or obesity was positively correlated with age. Post-tonsillectomy bleeding was recorded in 11.1 per cent of underweight patients, 18.9 per cent of normal weight patients and 18.7 per cent of overweight patients (p = 0.7). Data stratification (according to age and weight) did not alter the post-tonsillectomy bleeding risk (p = 0.8).
Overweight or obesity did not increase the risk of post-tonsillectomy haemorrhage in either children or adults.
Heteroepitaxial CoxNi1−xSi2 layers with good crystalline quality have been formed by ion beam synthesis. Rutherford Backscattering (RBS) - Channeling, Auger Electron Spectroscopy (AES), Transmission Electron Microscopy (TEM) and X-Ray Diffraction (XRD) have been used to study the buried layers. For a sample with x=0.66, we found that this ternary silicide layer contains 11% type B and 89% type A orientation. The TEM investigation reveals that the type B component is mainly located at the interfaces with a thickness of a few monolayers. XRD studies show that the strain of the type B component is smaller than that of the type A component, and this is probably the reason for such a unique distribution of the type B component in the epilayer.
We studied the stellar populations, distribution of dark matter, and dynamical structure of a sample of 25 early-type galaxies in the Coma and Abell~262 clusters. We derived dynamical mass-to-light ratios and dark matter densities from orbit-based dynamical models, complemented by the ages, metallicities, and α-element abundances of the galaxies from single stellar population models. Most of the galaxies have a significant detection of dark matter and their halos are about 10 times denser than in spirals of the same stellar mass. Calibrating dark matter densities to cosmological simulations we find assembly redshifts zDM ≈ 1–3. The dynamical mass that follows the light is larger than expected for a Kroupa stellar initial mass function, especially in galaxies with high velocity dispersion σeff inside the effective radius reff. We now have 5 of 25 galaxies where mass follows light to 1–3 reff, the dynamical mass-to-light ratio of all the mass that follows the light is large (≈ 8–10 in the Kron-Cousins R band), the dark matter fraction is negligible to 1–3 reff. This could indicate a ‘massive’ initial mass function in massive early-type galaxies. Alternatively, some of the dark matter in massive galaxies could follow the light very closely suggesting a significant degeneracy between luminous and dark matter.
Heteroepitaxial CoxNi1-xSi2 layers with good crystalline quality have been formed by ion beam synthesis. Rutherford Backscattering (RBS) - Channeling, Auger Electron Spectroscopy (AES), Transmission Electron Microscopy (TEM) and X-Ray Diffraction (XRD) have been used to study the buried layers. For a sample with x=0.66, we found that this ternary suicide layer contains 11% type B and 89 % type A orientation. The TEM investigation reveals that the type B component is mainly located at the interfaces with a thickness of a few monolayers. XRD studies show that the strain of the type B component is smaller than that of the type A component, and this is probably the reason for such a unique distribution of the type B component in the epilayer.
The growth of FexNy thin films on GaAs, In0.2Ga0.8As, and Si02/Si substrates using an ultra high-vacuum (UHV) deposition chamber equipped with electron cyclotron resonance (ECR) microwave plasma source is presented. The structural properties of the deposited films have been measured using various techniques as x-ray diffraction (XRD), Auger electron spectroscopy (AES), and transmission electron microscopy (TEM). The results of XRD measurements show that the films consist of a combination of α-Fe, α'-Fe, γ-Fe4N, and α”- Fe16N2 phases. The depth profiles, calculated from the Auger peak intensities, show a uniform nitrogen concentration through the films. The TEM reveals a columnar structure of these films. The properties of the different Fe-N layers have been exploited in the fabrication of Fe(N) / FexNy / Fe trilayer structures, where Fe(N) means a slightly nitrogen doped Fe film. The magneto-transport properties of this trilayer structure grown on In0.2Ga0.8As substrates are presented.
τ MnAl / Co superlattices are grown epitaxially on GaAs (100) substrates by molecular beam epitaxy. High angle XRD spectra are analysed and indicate that good structural quality is achieved. The behaviour of the superlattice upon annealing is described and compared with inplane and out of plane magnetization data. Extraordinary hall effect measurements show low field switching comparable to MnAl thin films. Arguments on how structural properties are affecting the magnetic properties are discussed.
This paper discusses metal organic chemical vapor deposited (MOCVD) HfO2 layers using tetrakis(diethylamido)hafnium (TDEAH) as precursor. We have studied the influence of the starting surface and deposition temperature on the growth kinetics and physical properties of the HfO2 layers. Important characteristics such as crystalline state, density, and organic contamination in the layers were found to be dependent on these parameters.
Typical for this deposition process is the formation of an interfacial layer underneath the high-k layer. Its composition and thickness, affecting scaling of the equivalent oxide thickness, are shown to be closely related to the HfO2 process parameters mentioned above.
Finally, we will show electrical results for HfO2/polySi gate stacks indicating the effect for deposition temperature.
Targeting very thin equivalent oxides (<1 nm) requires the deposition of (very) thin dielectrica onto silicon surfaces with minimal interfacial oxide. Typically, high-k dielectric layers are deposited using ALD or MOCVD with, at present, a prime emphasis on Hf-based high-k dielectrics, either as pure HfO2, as silicate or mixed with Al2O3. In some cases nitrogen is added to improve the high-temperature stability. Depending on the deposition conditions ALD as well as MOCVD show serious deficiencies in terms of film closure and material density for ultra thin (<3 nm) films. Various surface preparation methods and deposition conditions are used to improve the film quality. Detailed studies on the film growth and its evolution requires the use of many analytical methods such as Rutherford Backscattering Spectrometry, Low Energy Ion Scattering, Time-of-flight SIMS, (spectroscopic) ellipsometry and X-ray photoelectron spectroscopy. When trying to correlate the results in terms of film thickness, apparent discrepancies can be observed which relate to non-homogeneous growth and reduced material density.
The growth of FexNy thin films on GaAs, In0.2Ga0.8As, and SiO2/Si substrates using an ultra high-vacuum (UHV) deposition chamber equipped with electron cyclotron resonance (ECR) microwave plasma source is presented. The structural properties of the deposited films have been measured using various techniques as x-ray diffraction (XRD), Auger electron spectroscopy (AES), and transmission electron microscopy (TEM). The results of XRD measurements show that the films consist of a combination of α-Fe, α'-Fe, y-Fe4N, and α”- Fe16N2 phases. The depth profiles, calculated from the Auger peak intensities, show a uniform nitrogen concentration through the films. The TEM reveals a columnar structure of these films. The properties of the different Fe-N layers have been exploited in the fabrication of Fe(N) / FexNy / Fe trilayer structures, where Fe(N) means a slightly nitrogen doped Fe film. The magneto-transport properties of this trilayer structure grown on In0.2Ga0.8As substrates are presented.
In the quest for ever smaller transistor dimensions, the well-known and reliable SiO2 gate dielectric material needs to be replaced by alternatives whith higher dielectric constants in order to reduce the gate leakage. Candidate materials are metal oxides such as HfO2. Themost promising deposition techniques, next to Physical Vapor Deposition, appear to be ALCVD and MOCVD. In this paper, we compare the most important characteristics of layers from both proces techniques and assess their relevance to gate stack applications: density, crystallisation, impurities, growth mechanism, interfacial layers, dielectric constant, mobility. Although we find some minor differences, layers from both techniques mostly show striking similarities in many aspects, both positive and negative.
Few neuropsychological tests have been developed specifically for non-English speakers. Rather, assessment measures are often derived from English source texts (STs) and translated into foreign language target texts (TTs). An abundant literature describes the potential for translation error occurring in test construction. While the neuropsychology community has striven to correct these inadequacies, interdisciplinary approaches to test translation have been largely ignored. Translation studies, which has roots in linguistics, semiotics, computer science, anthropology, and philosophy, may provide a much-needed framework for test development. We aim to apply specific aspects of Descriptive Translation Studies to present unique and heretofore unapplied frameworks to the socio-cultural conceptualizations of translated tests. In doing so, a more theoretical basis for test construction will be explored. To this end, translation theory can provide valuable insights toward the development of linguistically and culturally relevant neuropsychological test measures suitable for an increasingly diverse patient base. (JINS, 2010, 16, 227–232.)
The high-energy, low-accumulation NW Iberian shelf features three confined Holocene mud depocentres. Here, we show that the evolution of such depocentres follows successive steps. The flooding of inner shelf zones and river catchment areas by the late deglacial sea-level rise provided the precondition for shelf mud deposition. Following this, the Holocene deceleration of the sea-level rise caused a rapid refill of the accommodation space within river valleys. Subsequently, the export of major amounts of fines was initiated. The initial onset and loci of shelf mud deposition were related to deposition-favouring conditions in mid-shelf position or to the presence of morphological highs, which act as sediment traps by providing protection against stronger hydrodynamic energy. The detailed reconstruction of the Holocene depocentre evolution shows for the first time that the expansion of such shelf mud deposits cannot only occur by linear growth off the associated sediment source. Rather, they might develop around centres that are fully disconnected from the source of original sediment supply, and expand later into specific directions. Based on these differences and on the connection of the individual mud depocentres to the material source we propose a conceptual subdivision of the group “mid-shelf mud depocentres”.
Epidemiological studies suggest that the Hispanic population is at increased risk for neurological disorders. Yet, few assessment measures have been developed for, adapted to, or normalized with Spanish-speakers. The Neuropsychological Screening Battery for Hispanics (NeSBHIS) was developed to address the lack of resources available to this underserved community. Although the NeSBHIS possesses robust construct validity and clinical utility in a community-based sample, these properties remain largely untested in neurological populations. One hundred and twenty-seven Spanish-speaking Hispanic patients with confirmed epilepsy (mean age = 37.8, SD = 13.3) were evaluated using the NeSBHIS. All participants self-identified as “Hispanic” and immigrated from Spanish-speaking countries. Data were analyzed using confirmatory factor analysis with the a priori assumption that variables would load according to theoretical expectations reported by Pontón and colleagues (2000). The overall model fit indices were in the desired range: Comparative Fit Index = 0.936, Tucker Lewis Index = 0.915, RMSEA = 0.090, and SRMR = 0.069. All NeSBHIS subtests loaded significantly (p < .001) on their respective factors; the standardized loadings were high, ranging from 0.562 to 0.995, with the exception of Block Design (–0.308). Overall, findings suggest that the NeSBHIS has robust construct validity in a neurological sample. (JINS, 2009, 15, 217–224.)
Green rusts, GRs, can act as both sorbents and reductants towards selected pollutants. Organo-GRs are expected to combine these properties with a high affinity for hydrophobic substances. A novel organo-GR, GRLAS, was synthesized by incorporating a mixture of linear alkylbenzenesulphonates (LAS) into the interlayer space of synthetic sulphate green rust, GRSO4 . Mössbauer analysis of GRLAS indicates that the structure of the organo-GR is very similar to that of the initial GRSO4 with regard to the FeII/FeIII ratio and local coordination of Fe atoms. X-ray diffraction demonstrates that the GRLAS formed was well ordered, although a mixture of surfactant was used for intercalation. The basal spacings of the GRLAS and the kinetics of the ion-exchange process were dependent on the initial surfactant loading; basal spacings of ~2.85 nm were obtained at LAS solution concentrations >10 mM. The ratio LASadsorbed/SO42–desorbed significantly exceeded the stoichiometric ratio of 2 during the initial part of the ion-exchange process (t = 5 h). However, this ratio was reached progressively with time. GRSO4 preferentially sorbed LAS homologues with long alkyl chains over short ones. Carbon tetrachloride was successfully adsorbed into GRLAS. The adsorption isotherm was linear with a distribution coefficient, Kd, of 505±19 litre kg–1.
This paper begins with the observation that half of all graphs containing no induced path of length 3 are disconnected. We generalize this in several directions. First, we give necessary and sufficient conditions (in terms of generating functions) for the probability of connectedness in a suitable class of graphs to tend to a limit strictly between zero and one. Next we give a general framework in which this and related questions can be posed, involving operations on classes of finite structures. Finally, we discuss briefly an algebra associated with such a class of structures, and give a conjecture about its structure.
The class of graphs containing no induced path of length 3 has many remarkable properties, stemming from the following well-known observation. Recall that an induced subgraph of a graph consists of a subset S of the vertex set together with all edges contained in S.
Proposition. Let G be a finite graph with more than one vertex, containing no induced path of length 3. Then G is connected if and only if its complement is disconnected.
Proof. It is trivial that the complement of a disconnected graph is connected. Moreover, since P3 is self-complementary, the property of containing no induced P3 is self-complementary. So let G be a minimal counterexample: thus, G and Ḡ are connected but, for any vertex v, either G – v or G – v is disconnected. Choose a vertex v and assume, without loss, that G - v is disconnected. Then v is joined to a vertex in each component of G – v.
An interfacial SiO2 hampers a silicidation reaction between Co and Si. A refractory metal cap is believed to block ambient oxygen diffusing toward the Co/Si interface. However, an interfacial SiO2 can also be present prior to and/or during the annealing. This work reports on our findings of the interaction between SiO2 and Co layers capped with refractory metals. It was found that Ti diffuses through the Co layer and segregates underneath the Co, which leads to the reduction of SiO2 and the formation of free Si. The free Si in-diffuses and reaches the original Ti surface. On the other hand, TiN shows a very inert behavior compared to Ti. The results are discussed in connection with Co silicidation processes.
This paper begins with the observation that half of all graphs containing no induced
path of length 3 are disconnected. We generalize this in several directions. First, we give
necessary and sufficient conditions (in terms of generating functions) for the probability
of connectedness in a suitable class of graphs to tend to a limit strictly between zero and
one. Next we give a general framework in which this and related questions can be posed,
involving operations on classes of finite structures. Finally, we discuss briefly an algebra
associated with such a class of structures, and give a conjecture about its structure.