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Mass gatherings attended by large crowds are an increasingly common feature of society. In parallel, an increased number of studies have been conducted to identify those variables that are associated with increased medical usage rates.
To identify studies that developed and/or validated a statistical regression model predicting patient presentation rate (PPR) or transfer to hospital rate (TTHR) at mass gatherings.
Prediction modeling studies from 6 databases were retained following systematic searching. Predictors for PPR and/or TTHR that were included in a multivariate regression model were selected for analysis. The GRADE methodology (Grades of Recommendation, Assessment, Development, and Evaluation) was used to assess the quality of evidence.
We identified 11 prediction modeling studies with a combined audience of >32 million people in >1500 mass gatherings. Eight cross-sectional studies developed a prediction model in a mixed audience of (spectator) sports events, music concerts, and public exhibitions. Statistically significant variables (p<0.05) to predict PPR and/or TTHR were as follows: accommodation (seated, boundaries, indoor/outdoor, maximum capacity, venue access), type of event, weather conditions (humidity, dew point, heat index), crowd size, day vs night, demographic variables (age/gender), sports event distance, level of competition, free water availability, and specific TTHR-predictive factors (injury status: number of patient presentations, type of injury). The quality of the evidence was considered as low. Three studies externally validated their model against existing models. Two validation studies showed a large underestimation of the predicted patients presentations or transports to hospital (67-81%) whereas one study overestimated these outcomes by 10-28%.
This systematic review identified a comprehensive list of relevant predictors which should be measured to develop and validate future models to predict medical usage at mass gatherings. This will further scientifically underpin more effective pre-event planning and resource provision.
Dans cette contribution, nous nous intéressons à l'origine et au développement de la construction [adverbe de degré + nom]: C'est très théâtre, c'est-à-dire très faux. De nos jours, cette construction se présente comme un puissant outil de recatégorisation contextuelle pour exprimer un rapport de ressemblance basé sur une analogie avec un concept nominal. Sur la base d'une recherche de corpus outillée, nous montrons que la construction-hôte [ADVdegré + ADJ] a pu s'ouvrir à la catégorie nominale à partir d'un petit noyau dur de noms humains, en partie qualitatifs, tirant profit de certaines propriétés structurelles du français de l’époque. Par la suite, la construction s'est diversifiée vers d'autres classes sémantiques (noms inanimés, noms propres, etc.) et a progressivement attiré une gamme plus diversifiée de types lexicaux dans son orbite. Elle n'a cessé de gagner en productivité, tout en réduisant son fonds lexical d'origine à la portion congrue.
La présente contribution porte sur tourner et virer, deux verbes attributifs (p. ex. elle a viré/tourné folle) qui ne sont pas encore reconnus pleinement par la tradition grammaticale normative ni dans les travaux des linguistes. Elle vise à établir le profil distributionnel / collocationnel de ces deux verbes qui semblent opérer dans le même domaine sémantico-fonctionnel, afin de mettre à nu les subtiles divergences au niveau de leur profil sémantique. Celles-ci sont rattachées à la sémantique de base du verbe lexical, laissant entrevoir dans ces emplois grammaticalisés des effets dus à la « persistance lexicale » (lexical persistence). Afin d'objectiver au maximum les profils distributionnels des deux verbes (et partant leur profil sémantique), les outils statistiques offerts par la méthode collostructionnelle (Stefanowitsch et Gries 2003; Gries et Stefanowitsch 2004) sont mis à profit. En outre, la combinaison de l'approche collocationnelle et de l'analyse morphosyntaxique amène à distinguer l'emploi proprement attributif des deux verbes d'un emploi directionnel abstrait homonymique (l'entreprise a viré solaire), qui est encore proche de la construction prépositionnelle (virer à / tourner à).
This paper deals with the distribution of power among Belgian political parties during the interwar period. In the 1930s Belgium, like most European countries, was confronted with the electoral success of extreme right- and left-wing parties that wanted to change the existing political system into an authoritarian one. Usually, historians draw attention to the rapidly growing share of seats in Parliament held by extreme parties as a sign of their increasing influence on Belgian politics. Among game theorists, however, it is widely accepted that the proportion of seats is a poor proxy for power relations (Schotter, 1979). It is indeed possible that a political party acquiring a higher proportion of seats in Parliament loses its capacity to influence the outcome of a vote, and vice versa.
Efficiency analysis is used for assessing links between technical efficiency (TE) of livestock farms and animal diseases. However, previous studies often do not make the link with the allocation of inputs and mainly present average effects that ignore the often huge differences among farms. In this paper, we studied the relationship between exposure to gastrointestinal (GI) nematode infections, the TE and the input allocation on dairy farms. Although the traditional cost allocative efficiency (CAE) indicator adequately measures how a given input allocation differs from the cost-minimising input allocation, they do not represent the unique input allocation of farms. Similar CAE scores may be obtained for farms with different input allocations. Therefore, we propose an adjusted allocative efficiency index (AAEI) to measure the unique input allocation of farms. Combining this AAEI with the TE score allows determining the unique input-output position of each farm. The method is illustrated by estimating efficiency scores using data envelopment analysis (DEA) on a sample of 152 dairy farms in Flanders for which both accountancy and parasitic monitoring data were available. Three groups of farms with a different input-output position can be distinguished based on cluster analysis: (1) technically inefficient farms, with a relatively low use of concentrates per 100 l milk and a high exposure to infection, (2) farms with an intermediate TE, relatively high use of concentrates per 100 l milk and a low exposure to infection, (3) farms with the highest TE, relatively low roughage use per 100 l milk and a relatively high exposure to infection. Correlation analysis indicates for each group how the level of exposure to GI nematodes is associated or not with improved economic performance. The results suggest that improving both the economic performance and exposure to infection seems only of interest for highly TE farms. The findings indicate that current farm recommendations regarding GI nematode infections could be improved by also accounting for the allocation of inputs on the farm.
We address the question, in decision theory, of how the value of risky options (gambles) should be assessed when they have no finite standard expected value, that is, where the sum of the probability-weighted payoffs is infinite or not well defined. We endorse, combine and extend (1) the proposal of Easwaran (2008) to evaluate options on the basis of their weak expected value, and (2) the proposal of Colyvan (2008) to rank options on the basis of their relative expected value.
Other considerations and issues in pediatric hepatology
Donald A. Novak, Department of Pediatrics, University of Florida, and Division of Pediatric Gastroenterology, Shands Hospital, Gainesville, FL, USA,
Gregory Y. Lauwers, Gastrointestinal Pathology Service and Department of Pathology, Massachusetts General Hospital; and Department of Pathology, Harvard Medical School, Boston, MA, USA,
Richard L. Kradin, Gastrointestinal Pathology Service and Department of Pathology, Massachusetts General Hospital; and Department of Pathology, Harvard Medical School, Boston, MA, USA
In this paper the electrical properties of epitaxial CoSi2 on Si obtained by solid-state reaction of a Ti/Co bimetallic layer are investigated. Low temperature resistivity, magnetoresistance and Hall data are presented. The CoSi2ISi Schottky diodes are characterised by current - voltage and capacitance - voltage measurements at temperatures varying between - 100°C and 60°C.
An investigation of the influence of an intermediate titanium thin film on the silicidation reaction between an overlying iron film and the (100)-oriented silicon substrate is presented. The Fe-Ti bilayers were obtained by consecutive sputtering of a Ti layer and an Fe layer on Si substrates. In addition, single iron layers were made by sputtering for comparison with the bilayers. By subsequent rapid-thermnal processing (RTP), depending on the annealing conditions, both the semiconducting β- and the metallic α-FeSi2 thin films could be formed. The phase formation has been investigated as a function of the thickness of the titanium layer, the annealing time and temperature. In this paper the first results on iron disilicide formation through Fe-Ti-Si diffusion couples are shown. Characterisation of the FeSi2 layers using Rutherford backscattering spectrometry (RBS), channelling RBS, X-ray diffraction (XRD), sheet resistivity measurements will be presented.
Measurements of the electrical resistivity and magnetoresistivity are reported for 100 nm buried α-FeSi2 in the temperature range 1.2 to 300 K, and in magnetic fields up to 5 Tesla.The metallic α-FeSi2 phase, formed by ion-beam synthesis and subsequent rapid-thermal annealing, is found to have a high residual resistivity of about 227 μΩ2 cm. Furthermore, a minimum in the electrical resistivity is found at 40 K. Combined with mnagnetore si stance measurements it is concluded that this minimum cannot be attributed to the Kondo effect, but is caused by weak localisation and spin-orbit interaction due to the very strong elastic scattering in the material. From the magnetoresistance measurements, at temperatures below 40 K, the relaxation times due to inelastic and spin-orbit scattering are deduced. The inelastic scattering rate is found to saturate below 4.2 K, and follow a T3 power law between 4.2 K to 40 K.
The relationship between silicide thickness, sheet resistance and silicon consumption is experimentally checked for Co-disilicide and Ni-monosilicide. The reverse bias leakage current of shallow Ni-silicided and Co-silicided square diodes is compared for varying junction depth and varying silicide thickness. A lower reverse bias leakage current is obtained for a Ni-silicided shallow junction as compared to its Co-silicided counterpart. This can be attributed to the reduced silicon consumption. The Ti cap does not play an active role during the Ni-silicidation of narrow active area and poly lines. It is shown that a Ni-silicidation process is scalable without Ti cap.
Making use of SPER (Solid Phase Epitaxial Regrowth) As and B deep source/drain junctions with high activation can be obtained at temperatures below 700°C. However, higher thermal budget is required to regrow and activate the dopants in the poly gates. Low junction leakage and low contact resistance can be obtained for Ni-silicided As and B SPER junctions making use of deep As and B implants. Because of the low thermal budget source/drain junctions obtained by SPER are an attractive alternative to conventional spike annealed junctions for technologies making use of metal gates.
Junctions were formed in thin SiGe/strained Si substrates with a thickness of 250-350 nm to assess the effect of different buffer layer parameters (bandgap, dislocations, thickness) on the junction leakage density that can be expected in MOSFET devices. The implantations used are standard well, channel and Highly Doped Drain (HDD) implants. Both p+/n and n+/p junctions were evaluated. The total thickness of the buffer layers was varied to compare the effect of different structural layers on the diode leakage. This investigation shows that the effect of an increased defect density is dominant at room temperature for the strained Si samples, resulting in 4-5 orders of magnitude increase in leakage. However, there is a different gradation in leakage dependence for thick and thin buffer layers, especially at higher temperatures.
Silicidation of small features of various geometries and sizes using Ni-silicide was studied. Effects of dopants, surface preparation and silicidation parameters on silicide morphology were investigated. It was found that Ni silicide thickness and quality of the silicide/silicon interface (presence of NiSi2 pyramids) are dependent on the area dimensions and geometry. NiSi formed on narrow lines is thicker compared to wide areas. We found that pyramids of epitaxial NiSi2 protruding into the Si substrate are formed during the silicidation of undoped, boron-doped and BF2-doped active areas. The presence of pyramids was not observed on As-doped silicon. Rough interface due to the pyramids could be the reason for a more pronounced linewidth dependence of leakage current in the case of p+/n diodes. A higher density of pyramids was found on narrow lines (below 0.2μm) and particularly islands structures. No pyramids were found when a Ge preamorphisation implant was used.
Effects of alloying Ni with Pt and Ta on silicide properties for CMOS technology have been studied. It was found that Pt is soluble in NiSi, which is in line with literature, whereas Ta segregates towards the surface during thermal treatment. Additionally, Ta retards NiSi formation at low temperature. Thermal stability of NiSi on Si is improved more efficiently by alloying Ni with Pt compared to Ta. Silicide/diffusion contact resistance is extracted using the Transmission Line Structure. In our experiments, contact resistivity appeared to be virtually unaffected with respect to the alloying element. Thermal stability on narrow poly Si structures was also improved when Ni was alloyed with Pt. Similar leakage currents for Ni and Ni(Pt) silicides on N+ and P+ junctions were obtained. The results presented in this work suggest that Pt is a better candidate as alloying element to improve NiSi thermal stability for CMOS processes than Ta.
This paper presents an overview of Ni-alloy (Ni, Ni-Pt and Ni-Ta) silicide development for the 45 nm node and beyond, including applications to self-aligned silicide (SALICIDE) processes, reaction with SiGe and strained Si on SiGe, and applications to fully silicided (FUSI) gates. Key SALICIDE issues addressed include the use of spike or low temperature rapid thermal processes (RTP) to control silicidation and junction leakage on small features, factors affecting the formation of epitaxial pyramidal NiSi2 grains, and NiSi thermal stability and agglomeration kinetics. Alloying with Pt or Ta is shown to improve thermal stability of NiSi films, although with quite different behaviors. While Pt is incorporated predominantly in solution in NiSi, Ta segregates to the surface of the films. Ni-Pt alloy silicides were also found to achieve low sheet resistance on narrow gates, low contact resistivity and low junction leakage, making them attractive for CMOS applications. For the Ni/SiGe reaction, a narrower RTP process window for low sheet resistance and a lower activation energy for agglomeration were observed when compared to the Ni/Si reaction. The lower thermal stability was correlated to Ge segregation from the Ni(SiGe) films. The Ni/doped poly-Si reaction was studied for FUSI gate applications, showing a retardation of the silicidation kinetics for high B doses and a large pile- up of dopants (for As, B or P) at the NiSi/SiO2 interface due to dopant snowplow during silicidation. The work function (WF) of NiSi was observed to shift with the addition of dopants, effect attributed to modifications of the interface dipole by the pile-up of dopants. No significant degradation was observed when comparing gate oxide breakdown statistics for Ni FUSI to conventional poly-Si gates. The process window for a FUSI gate-last process (performed after S/D Ni silicidation) was evaluated showing a potential integration problem due to possible degradation of the S/D silicide during the FUSI gate reaction.
The feasibility of the SPER junction process as a reasonable alternative to the spike anneal junction is proved in this work. Good control of the SCE and performance competitive results as compared to the spike junction are obtained. An analysis of the interaction between the halo dopant and the SPER junctions has been carried out; it is shown that the performance degrades with increasing halo dose as a consequence of an overlap resistance problem.
The implantation of high doses of Co in Si1−xGex alloys is investigated for several Ge concentrations. The aim of this work is to monitor phase formation, layer formation and crystalline structure of the layers. The samples are evaluated by RBS, SIMS, TEM and sheet resistance measurements. Similar as for the implantation of high doses of Co in Si, buried layer formation of CoSi2 in the Si1−x Gex alloy is observed with a concommitant expulsion of Ge out of the silicide layer.
In-situ emissivity measurements at a wavelength of 2.4 μα were used to monitor RTP Co silicidation on crystalline and polycrystalline silicon substrates. The influence of various parameters influencing the silicidation reaction was extensively studied. It is shown that particularly the phase transformation from CoSi to the final suicide phase, COSi2, strongly depends on parameters such as background doping level and type of substrate. This is illustrated for As-doped substrates. The method is extremely sensitive for the in-situ detection of the thermal degradation of thin COSi2 films at high temperatures, which is demonstrated for 25 nm COSi2 layers on highly As-doped c-Si substrates.