928 resultados para Americium 241, standard deviation
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BACKGROUND: The numbers of people attending emergency departments (EDs) at hospitals are increasing. We aimed to analyse trends in ED attendance at a Swiss university hospital between 2002 and 2012, focussing on age-related differences and hospital admission criteria. METHODS: We used hospital administrative data for all patients aged ≥16 years who attended the ED (n = 298,306) at this university hospital between 1 January 2002, and 31 December 2012. We descriptively analysed the numbers of ED visits according to the admission year and stratified by age (≥65 vs <65 years). RESULTS: People attending the ED were on average 46.6 years old (standard deviation 20 years, maximum range 16‒99 years). The annual number of ED attendances grew by n = 6,639 (27.6%) from 24,080 in 2002 to 30,719 in 2012. In the subgroup of patients aged ≥65 the relative increase was 42.3%, which is significantly higher (Pearson's χ2 = 350.046, df = 10; p = 0.000) than the relative increase of 23.4% among patients <65 years. The subgroup of patients ≥65 years attended the ED more often because of diseases (n = 56,307; 85%) than accidents (n = 9,844; 14.9%). This subgroup (patients ≥65 years) was also more often admitted to hospital (Pearson's χ2 = 23,377.190; df = 1; p = 0.000) than patients <65 years. CONCLUSIONS: ED attendance of patients ≥65 years increased in absolute and relative terms. The study findings suggest that staff of this ED may want to assess the needs of patients ≥65 years and, if necessary, adjust the services (e.g., adapted triage scales, adapted geriatric screenings, and adapted hospital admission criteria).
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OBJECTIVE: To determine the number of punctures in fine-needle aspiration biopsies required for a safe cytological analysis of thyroid nodules. MATERIALS AND METHODS: Cross-sectional study with focus on diagnosis. The study population included 94 patients. RESULTS: The mean age of the patients participating in the study was 52 years (standard-deviation = 13.7) and 90.4% of them were women. Considering each puncture as an independent event, the first puncture has showed conclusive results in 78.7% of cases, the second, in 81.6%, and the third, in 71.8% of cases. With a view to the increasing chance of a conclusive diagnosis at each new puncture, two punctures have showed conclusive results in 89.5% of cases, and three punctures, in 90.6% of cases with at least one conclusive result. CONCLUSION: Two punctures in fine-needle aspiration biopsies of thyroid nodules have lead to diagnosis in 89.5% of cases in the study sample, suggesting that there is no need for multiple punctures to safely obtain the diagnosis of thyroid nodules.
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The objective of this study was to evaluate the methodological characteristics of cost-effectiveness evaluations carried out in Spain, since 1990, which include LYG as an outcome to measure the incremental cost-effectiveness ratio. METHODS: A systematic review of published studies was conducted describing their characteristics and methodological quality. We analyse the cost per LYG results in relation with a commonly accepted Spanish cost-effectiveness threshold and the possible relation with the cost per quality adjusted life year (QALY) gained when they both were calculated for the same economic evaluation. RESULTS: A total of 62 economic evaluations fulfilled the selection criteria, 24 of them including the cost per QALY gained result as well. The methodological quality of the studies was good (55%) or very good (26%). A total of 124 cost per LYG results were obtained with a mean ratio of 49,529
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Abstract Objective: To analyze the prevalence of anatomical variations of celiac arterial trunk (CAT) branches and hepatic arterial system (HAS), as well as the CAT diameter, length and distance to the superior mesenteric artery. Materials and Methods: Retrospective, cross-sectional and predominantly descriptive study based on the analysis of multidetector computed tomography images of 60 patients. Results: The celiac trunk anatomy was normal in 90% of cases. Hepatosplenic trunk was found in 8.3% of patients, and hepatogastric trunk in 1.7%. Variation of the HAS was observed in 21.7% of cases, including anomalous location of the right hepatic artery in 8.3% of cases, and of the left hepatic artery, in 5%. Also, cases of joint relocation of right and left hepatic arteries, and trifurcation of the proper hepatic artery were observed, respectively, in 3 (5%) and 2 (3.3%) patients. Mean length and caliber of the CAT were 2.3 cm and 0.8 cm, respectively. Mean distance between CAT and superior mesenteric artery was 1.2 cm (standard deviation = 4.08). A significant correlation was observed between CAT diameter and length, and CAT diameter and distance to superior mesenteric artery. Conclusion: The pattern of CAT variations and diameter corroborate the majority of the literature data. However, this does not happen in relation to the HAS.
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UNLABELLED: It is uncertain whether bone mineral density (BMD) can accurately predict fracture in kidney transplant recipients. Trabecular bone score (TBS) provides information independent of BMD. Kidney transplant recipients had abnormal bone texture as measured by lumbar spine TBS, and a lower TBS was associated with incident fractures in recipients. INTRODUCTION: Trabecular bone score (TBS) is a texture measure derived from dual energy X-ray absorptiometry (DXA) lumbar spine images, providing information independent of bone mineral density. We assessed characteristics associated with TBS and fracture outcomes in kidney transplant recipients. METHODS: We included 327 kidney transplant recipients from Manitoba, Canada, who received a post-transplant DXA (median 106 days post-transplant). We matched each kidney transplant recipient (mean age 45 years, 39 % men) to three controls from the general population (matched on age, sex, and DXA date). Lumbar spine (L1-L4) DXA images were used to derive TBS. Non-traumatic incident fracture (excluding hand, foot, and craniofacial) (n = 31) was assessed during a mean follow-up of 6.6 years. We used multivariable linear regression models to test predictors of TBS, and multivariable Cox proportional hazard regression was used to estimate hazard ratios (HRs) per standard deviation decrease in TBS to express the gradient of risk. RESULTS: Compared to the general population, kidney transplant recipients had a significantly lower lumbar spine TBS (1.365 ± 0.129 versus 1.406 ± 0.125, P < 0.001). Multivariable linear regression revealed that receipt of a kidney transplant was associated with a significantly lower mean TBS compared to controls (-0.0369, 95 % confidence interval [95 % CI] -0.0537 to -0.0202). TBS was associated with fractures independent of the Fracture Risk Assessment score including BMD (adjusted HR per standard deviation decrease in TBS 1.64, 95 % CI 1.15-2.36). CONCLUSION: Kidney transplant recipients had abnormal bone texture as assessed by TBS and a lower lumbar spine TBS was associated with fractures in recipients.
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A flow system based on multicommutation and binary sampling process was developed to implement the sample zone trapping technique in order to increase the spectrophotometric analytical range and to improve sensitivity. The flow network was designed with active devices in order to provide facilities to determine sequentialy analyte with a wide concentration range, employing a single pumping channel to propel sample and reagents solutions. The procedure was employed to determine ortophosphate ions in water samples of river and waste. Profitable features such as an analytical throughput of 60 samples determination per hour, relative standard deviation (r.s.d.) of 2% (n = 6) for a typical sample with concentration of 2.78 mg/L were achieved. By applying the paired t-test no significant difference at 95% confidence level was observed between the results obtained with the proposed system and those of the usual flow injection system.
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A flow system procedure for spectrophotometric determination of ascorbic acid in drugs based on [Fe3+(SCN-)n]+3-n complex decomposition by reduction is described. The flow network was constituted by a set of three-way solenoid valves, controlled by a microcomputer running a software wrote in QuickBasic 4.5 language. The feasibility of the procedure was ascertained by determining ascorbic acid in drug samples with mass ranging from 0.0018 up to 0.0180 g. The results showed an agreement of about 7% when compared with recommended method. Other profitable features such as a standard deviation of 1.5% (n = 7) and a throughput of 120 determinations per hour was also achieved.
Uma célula simples para adaptação de eletrodos seletivos comerciais em sistemas de análises em fluxo
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A simple flow cell for potentiometric detection is described. It was assembled by making use of two perspex pieces fixed together by means of four screws, and allow the connection of plane membrane conventional electrodes to flow system. Details about its construction are presented. The device performance was evaluated by making use of a cyanide ion-selective electrode. The relative standard deviation was about 0.5% with a detection limit of 8.0 x 10-6 mol CN- dm-3. Under experimental conditions, the linear range was 10-5 to10-2 mol dm-3.
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A new automated system for acid-base flow titrations is proposed. In the operation mode, several sample to titrant volumetric ratios are injected in an air segmented plug. Five three way solenoid valves and three acrilic junctions, assembled in a hidrodynamic injection system, were accountable for the monosegmented reagents plug formation. A turbulent flow reactor was used for a perfect mix of reagents in the plug. The detector system employed a glass combined electrode fitted in an acrilic holder. Titrations of hydrochloric, nitric and acetic acids, in several concentrations, were performed with standard sodium hidroxide, for evaluation of the efficiency of the system. The relative standard deviation of the determinations was about ±0,5% and each titration was carried out in 3-4 minutes. A Quick BASIC 4.5® program was developed for the titrator control.
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Selectivity studies for the determination of Cr(VI) using the catalytic oxidation of the o-dianisidine by hydrogen peroxide showed two distincts situations. In the first, when interferents were studied by a univariate procedure, Cr(III) and Cu(II) cause serious interferences even at the 2:1 proportion, relative to Cr(VI), while Fe(III) interfered at the 15:1 ratio and EDTA at the 10:1 ratio. On the other hand, when a multivariate investigation was performed, Cr(III) did not present any significant principal effects and its significant interaction effects were negative, in contrast to EDTA, that presented positive interaction effects although, like Cr(III), did not show significant interaction effects. In view of the interferent's action it become necessary to separate Cr(VI) by extraction with methylisobutylketone in a chloridric acid medium before its determination in vegetals and in wastewater from a cellulose industry samples. Using this procedure, the method precision is ±0,5% at the 10 ng/mL Cr(VI) concentration level. The detection and quantification limits, calculated by means of absorbance measurements of ten replicates of blank reagents were 1,1 and 3,2 ng/mL, respectively. The results obtained with real samples showed a relative standard deviation between 1,2% and 3,0% relative to their reference values.
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'Cachaça' is the Brazilian name for the spirit obtained from sugarcane. According to Brazilian regulations, it may be sold raw or with addition of sugar and may contain up to 5 mg/L of copper. Copper in "cachaça" was determined by titration with EDTA, using a homemade copper membrane electrode for end-point detection. It was found a pooled standard deviation of 0,057 mg/L and there was no significant difference between the results obtained by the potentiometric method and by flame atomic absorption spectrometry with standard addition. Among the 21 'cachaça' samples from 16 different brands analyzed, three overpassed the legal copper limit. For its characteristics of accuracy, precision, and speed, the potentiometric method may be employed advantageously in routine analysis, specially when low cost is a major concern.
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Tutkielman tavoitteena oli selvittää Suomen osakemarkkinoiden hinnoittamistehokkuutta johdon ennustepoikkeamien tapauksessa. Tarkastelu-ajanjakso on 1.1.2000–31.12.2006. Kiinnostuneita oltiin erityisesti keski-pitkän ja pitkän aikavälin (10 kaupankäyntivuorokautta ja 40 kaupankäyntivuorokautta) epänormaaleista tuotoista. Työn empiriaosuus suoritettiin tapahtumatutkimusmenetelmää hyväksikäyttäen. Empiriaosuudessa laskettiin ennustepoikkeaman aiheuttamat epänormaalit tuotot pienimmän neliösumman regressiota hyväksikäyttäen. Positiivisten poikkeamien aiheuttamat epänormaalit tuotot eivät poikenneet tilastollisesti markkinatuotoista millään tarkasteluvälillä. Negatiivisten epänormaalien tuottojen poikkeamaa havaittiin 10 kaupankäyntivuorokautta ennustepoikkeaman julkaisun jälkeen. Toimialakohtaisessa tarkastelussa parillisten otosten t-testissä havaittiin, että terveydenhuollon, rahoituksen ja informaatioteknologian epänormaalit tuotot poikkesivat markkinatuotoista. Yrityskohtaisia tekijöitä tutkittiin yksinkertaisella t-testillä. Näistä velkaisuusasteella, beetalla, päivätuottojen keskihajonnalla, päivittäisellä liikevaihdolla sekä P/E-luvulla havaittiin voi-tavan ennustaa mahdollisten ennustepoikkeamien esiintymistiheyttä. Sen sijaan markkina-arvolla ja P/B-luvulla ei havaittu yhteyttä ennustepoikkeamien esiintymistiheyteen. Tutkittaessa käyttäytymistieteellisen rahoituksen olettamaa kaupankäyntivolyymin kasvusta ennustepoikkeamaa ympäröivänä aikana ei tilastollista merkittävyyttä löydetty.
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An on-line electrodissolution procedure implemented in a flow injection system for determination of copper, zinc and lead in brasses alloys by ICP-AES is described. Sample dissolution procedure was carried out by using a PTFE chamber and a DC power supply with constant current. Solid sample was attached to chamber as anode and a gold tubing coupled in the chamber was used as cathode. An electrolytic solution flowing through the gold tubing closed the electric circuit with sample, in order to provide condition for electric dissolution when the DC power supply was switched on. The best results were achieved by using a 1.5 mol l-1 nitric acid solution as electrolyte and a 2.5 A current intensity. The procedure presented a good performance characterized by a relative standard deviation better than < 5% (n=5) and a sample throughput of 180 determinations per hour for Cu, Zn and Pb. Results were in agreement with those obtained by conventional acid dissolution (99% confidence level).
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Anodic electrodissolution procedure in a flow injection system for determination of constituents in alloys is discussed. This approach implement sample preparation procedure by using a chamber and a DC power supply with constant direct current. Solid sample was attached to chamber as anode. In this review a general overview of these procedure is presented. The procedure presented a good performance characterized by a high sample throughput determinations, good accuracy and relative standard deviation.
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A spectrophotometric flow injection analysis (FIA) procedure employing natural urease enzyme source for the determination of urea in animal blood plasma was developed. Among leguminous plants used in the Brazilian agriculture, the Cajanus cajan specie was selected as urease source considering its efficiency and availability. A minicolumn was filled with leguminous fragments and coupled to the FIA manifold, where urea was on-line converted to ammonium ions and subsequently it was quantified by spectrophotometry. The system was employed to determine urea in animal plasma samples without any prior treatment. Accuracy was assessed by comparison results with those obtained employing the official procedure and no significant difference at 90 % confidence level was observed. Other profitable features such as an analytical throughput of 30 determinations per hour, a reagent consumption of 19.2 mg sodium salicylate, 0.5 mg sodium hipochloride and a relative standard deviation of 1.4 % (n= 12) were also obtained.