647 research outputs found

    An efficiency analysis of banking systems: a comparison of European and United States large commercial banks using different functional forms.

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    This paper aims at investigation the efficiency of European and U.S. commercial banks. Scale and scope economies indicators, as well as a measurement of X-efficiency are derived from three cost functions: Fourier flexible form, translog and Box-Cox. This allows checking the stability and the robustness of the evidence across the different specifications. Our results over the period 1995-98 show that overall the average cost curve is relatively flat with some evidence of scale efficiency gains. More puzzling are the results on the presence of scope economies.

    Evaluating New Liquid Storable Bipropellants: Safety and Performance Assessments

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    Conventional storable bipropellants make use of hydrazine and its derivatives as fuels and nitrogen tetroxide as an oxidizer. In recent years, the toxicity character of these chemicals pushed the propulsion community towards “green” alternatives. Several candidates have been proposed among existing and newly developed chemicals, highlighting the need for a common and robust selection methodology. This paper aims at reviewing the most important selection criteria in the field of toxicity and discusses how to objectively define a green propellant, considering both the health and environmental hazards caused by the chemicals. Additionally, consistent figures of merit in the field of safety and handling operations and performance are proposed. In particular, operating temperatures, flammability and stability issues are discussed in the framework of physical hazards and storage requirements, while vacuum impulses, adiabatic flame temperature and sooting occurrence of the investigated couples are compared to the UDMH/NTO benchmark case. Hydrogen peroxide and nitrous oxide, and light hydrocarbons, alcohols and kerosene are selected from the open literature as promising green oxidizers and fuels, respectively. The identified methodology highlights merits and limitations of each chemical, as well as the fact that the identification of a universally best suited green couple is quite impractical. On the contrary, the characteristics of each propellant lead to a scenario of several “sub-optimal” couples, each of them opportunely fitting into a specific mission class

    Dance movement therapy and falls prevention

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    Falls are a leading cause of morbidity, healthcare use and mortality. Dance is a popular form of physical activity among older people and previous research has suggested that it may improve various health outcomes in this population, including balance, gait and muscle performance. A systematic review of the potential benefits of dance on falls and fear of falling is lacking. Thus, we conducted a systematic review considering all randomized controls trials (RCTs) investigating if dance can reduce falls and improve fear of falling in older adults. Major databases were searched from inception until 1 March 2017 and a total of 10 RCTs were identified, which included a total of 680 people (n = 356 dance, n = 324 control). Overall, the mean age of the samples was 69.4 years, and 75.2% were female. Across four RCTs, dance therapy reduced falls versus usual care in only one study. Dance therapy improved fear of falling in two out of three included RCTs. There were no serious adverse events reported in the RCTs. In summary, we found a paucity of studies investigating the effect of dance on falls and fear of falling and the evidence base is preliminary and equivocal. Given the heterogeneity of the included samples and interventions, in addition to the short-term follow-up, no firm conclusions can be drawn. However, dance appears to be safe and, given its popularity and demonstrated benefits on other health/wellbeing outcomes in older adults, it is important that future research considers its potential benefits on falls/fear of falling in older age

    Identification of onosma visianii roots extract and purified shikonin derivatives as potential acaricidal agents against tetranychus urticae

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    There is an increasing need for the discovery of reliable and eco-friendly pesticides and natural plant-derived products may play a crucial role as source of new active compounds. In this research, a lipophilic extract of Onosma visianii roots extract containing 12% of shikonin derivatives demonstrated significant toxicity and inhibition of oviposition against Tetranychus urticae mites. Extensive chromatographic separation allowed the isolation of 11 naphthoquinone derivatives that were identified by spectral techniques and were tested against Tetranychus urticae. All the isolated compounds presented effects against the considered mite and isobutylshikonin (1) and isovalerylshikonin (2) were the most active, being valuable model compounds for the study of new anti-mite agents

    Role of Pressure and Aluminum Size in Solid Propellant CCP Generation

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    Aluminum combustion in solid propellants generates condensed products leaving the burning surface. The population of this particles is quite wide, spanning from smoke-oxide to molten metal drops. Their properties depend upon both intrinsic propellant features and combustion conditions (e.g. composition, microstructure, combustion pressure, and propellant burning rate). In propellants, aluminum is typically used in the shape of a micrometric powder. This class of energetic materials produces spherical agglomerates having the size between some tens to few hundreds of micrometers. When the metal fuel turns to nanometric, flake-kind aggregates emerge from the burning surface. Some macroscopic properties, such as the burning rate, are affected. This paper presents some results obtained from a set of aluminized propellants based on inert binder (hydroxylterminated polybutadiene) and ammonium perchlorate. The effect of both powder size and pressure is explored in terms of ballistics and condensed combustion residues. A nonstraightforward trend with pressure emerges when the condensed combustion products of propellants containing micro-aluminum and nano-aluminum are compared

    Osteoarthritis increases the risk of cardiovascular disease: Data from the osteoarthritis initiative

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    Objective: Although osteoarthritis (OA) is a common condition in older adults, the role of OA in increasing cardiovascular disease (CVD) incidence is still debated. The aim of this study was to investigate the association between OA and the onset of CVD in a large database of American adults. Design: Longitudinal. Setting: Community-dwelling. Participants: People with OA or at high risk of OA. Measurements:. Osteoarthritis was defined as the presence of OA of the hand, knee, hip, back/neck or of other sites. CVD was defined as self-reported presence of heart attack, heart failure, stroke and other cerebral atherosclerotic conditions, and peripheral artery disease. Results: A total 4,265 persons without CVD (mean age=60.8 years, females=59.2%) at baseline were analyzed (1,775 with OA versus 2,490 without). Over a mean of 8.2 years, according to an adjusted Cox’s regression analysis for 11 potential baseline confounders, study participants with OA of any joint had a significantly higher risk of developing CVD compared to those without OA (Hazard ratio (HR): =1.27; 95% CI: 1.03-1.56). The presence of hand OA was associated with a higher risk of developing CVD (HR=1.31; 95%CI: 1.01-1.68) with respect to those who had no OA. Knee, hip and back/neck OA did not, instead, increase the risk of developing CVD. The association between OA and CVD was significant in the women, but not in the men. Conclusions: OA, in particular, when it affects the hand and is found in women, was associated with a higher risk of developing CVD

    Mitochondrial genetic haplogroups and cardiovascular diseases: Data from the Osteoarthritis Initiative

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    Background: Some case-control studies reported that mitochondrial haplogroups could be associated with the onset of cardiovascular diseases (CVD), but the literature regarding this topic is limited. We aimed to investigate whether any mitochondrial haplogroup carried a higher or lower risk of CVD in a large cohort of North American people affected by knee osteoarthritis or at high risk for this condition. Materials and methods: A longitudinal cohort study including individuals from the Osteoarthritis Initiative was done. Haplogroups were assigned through a combination of sequencing and PCR-RFLP techniques. All the mitochondrial haplogroups have been named following this nomenclature: HV, JT, UK, IWX, and superHV/others. The strength of the association between mitochondrial haplogroups and incident CVD was evaluated through a Cox’s regression analysis, adjusted for potential confounders, and reported as hazard ratios (HRs) with their 95% confidence intervals (CIs). Results: Overall, 3,288 Caucasian participants (56.8% women) with a mean age of 61.3±9.2 years without CVD at baseline were included. During a median follow-up of 8 years, 322 individuals (= 9.8% of baseline population) developed a CVD. After adjusting for 11 potential confounders at baseline and taking those with the HV haplotype as reference (the most frequent), those with JT carried a significant lower risk of CVD (HR = 0.75; 95%CI: 0.54–0.96; p = 0.03). Participants with the J haplogroup had the lowest risk of CVD (HR = 0.71; 95%CI: 0.46–0.95; p = 0.02). Conclusions: The presence of JT haplogroups (particularly J) may be associated with a reduced risk of CVD. However, this result was not based on a high level of statistical significance. Thus, future research with larger sample size is needed to assess whether our results can be corroborated
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