1,326 research outputs found
Does PIN Affect Equity Prices around the World?
This study examines the empirical controversy over the pricing effect of the Easley, Hvidkjaer, and O׳Hara (2002) probability of information-based trading, PIN, on a sample of 30,095 firms from 47 countries worldwide. Contrary to the empirical evidence of Easley, Hvidkjaer, and O׳Hara, but consistent with that of Duarte and Young (2009), we do not find that PIN exhibits a positive effect on a cross section of expected stock returns in international markets. Alternative information-based trading measures also display no effect on expected stock returns, corroborating our finding that information risk proxied by PIN, in general, has no pricing effect in world markets.postprin
Portuguese self-reported oral-hygiene habits and oral status
Background: Good oral health is essential for good general health and quality of life. In Portugal, there are few studies on oral-health habits and the population's perceptions of this behaviour. Objective: The main purpose of this study was to characterise the Portuguese population's self-reported oral-health status, habits and perceptions, as well as their demands regarding national oral health-care services. Methods: A randomised group of 1,395 individuals, > 15 years of age, was selected as a representative sample of the Portuguese population. Face-to-face interviews were conducted, based on a structured questionnaire with closed and semi-closed questions. The data were submitted for statistical analysis using SPSS. Results and discussion: A sample of 1,102 individuals answered the questionnaire. The great majority of the sample (97.6%) brushed their teeth daily, 70.3% had lost permanent teeth and 6.4% were edentulous. The loss of permanent teeth was statistically associated with poor oral-hygiene habits (P < 0.01). Moreover, 50.1% of the participants had experienced difficulty eating and/or drinking, 18% had felt ashamed of the appearance of their teeth and 69.3% had experienced toothache or gingival pain. A reduction in visits to a dentist in the previous 12 months was identified mainly for people from a lower social class (31.2%) and older people (29.4%). Conclusion: Evidence suggests that oral diseases might be more prevalent in Portuguese adults than the European average. Efforts should be made to promote good oral-hygiene habits among older people and people from lower social classes
Efficacy of Pregabalin in Acute Postoperative Pain Under Different Surgical Categories: a meta-analysis
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Effects of Intra-Operative Total Intravenous Anaesthesia with Propofol versus Inhalational Anaesthesia with Sevoflurane on Post-Operative Pain in Liver Surgery: A Retrospective Case-Control Study
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Impact of soil and water conservation measuren on catchment hydrological response: a case in north Ethiopia
Impact studies of catchment management in the developing world rarely include detailed hydrological components. Here, changes in the hydrological response of a 200-ha catchment in north Ethiopia are investigated. The management included various soil and water conservation measures such as the construction of dry masonry stone bunds and check dams, the abandonment of post-harvest grazing, and the establishment of woody vegetation. Measurements at the catchment outlet indicated a runoff depth of 5 mm or a runoff coefficient (RC) of 1·6% in the rainy season of 2006. Combined with runoff measurements at plot scale, this allowed calculating the runoff curve number (CN) for various land uses and land management techniques. The pre-implementation runoff depth was then predicted using the CN values and a ponding adjustment factor, representing the abstraction of runoff induced by the 242 check dams in gullies. Using the 2006 rainfall depths, the runoff depth for the 2000 land management situation was predicted to be 26·5mm(RCD 8%), in line with current RCs of nearby catchments. Monitoring of the ground water level indicated a rise after catchment management. The yearly rise in water table after the onset of the rains (ΔT) relative to the water surplus (WS) over the same period increased between 2002-2003 (ΔT/WS D 3·4) and 2006 (ΔT/WS >11·1). Emerging wells and irrigation are other indicators for improved water supply in the managed catchment. Cropped fields in the gullies indicate that farmers are less frightened for the destructive effects of flash floods. Due to increased soil water content, the crop growing period is prolonged. It can be concluded that this catchment management has resulted in a higher infiltration rate and a reduction of direct runoff volume by 81% which has had a positive influence on the catchment water balance. © 2010 John Wiley & Sons, Ltd
Gully cut- and- fill cycles as related to agromanagement : a historical curve number simulation in the Tigray Highlands
Gully cut-and-fill dynamics are often thought to be driven by climate and/or deforestation related to population pressure. However, in this case-study of nine representative catchments in the Northern Ethiopian Highlands, we find that neither climate changes nor deforestation can explain gully morphology changes over the twentieth century. Firstly, by using a Monte Carlo simulation to estimate historical catchment-wide curve numbers, we show that the landscape was already heavily degraded in the nineteenth and early twentieth century – a period with low population density. The mean catchment-wide curve number (> 80) one century ago was, under the regional climatic conditions, already resulting in considerable simulated historical runoff responses. Secondly, twentieth century land-cover and runoff coefficient changes were confronted with twentieth century changing gully morphologies. As the results show, large-scale land-cover changes and deforestation cannot explain the observed processes. The study therefore invokes interactions between authigenic factors, small-scale plot boundary changes, cropland management and sociopolitical forces to explain the gully cut processes. Finally, semi-structured interviews and sedistratigraphic analysis of three filled gullies confirm the dominant impact of (crop)land management (tillage, check dams in gullies and channel diversions) on gully cut-and-fill processes. Since agricultural land management – including land tenure and land distribution – has been commonly neglected in earlier related research, we argue therefore that it can be a very strong driver of twentieth century gully morphodynamics
Spinal cord stimulation for chronic non-cancer pain: a review of current evidence and practice
Spinal cord stimulation provides analgesia through electrical stimulation of the dorsal column of the spinal cord via electrode leads placed into the epidural space. In traditional tonic stimulation, a painful sensation is replaced with paraesthesia. Spinal cord stimulation is effective in reducing neuropathic pain, enhancing function, and improving quality of life in different chronic pain conditions. Currently, there is most evidence to support its use for failed back surgery syndrome when multidisciplinary conventional management is unsuccessful. Temporary trial leads are inserted in carefully selected patients to test their responsiveness prior to permanent implantation. Newer neuromodulation modalities are now available. These include burst stimulation, high-frequency stimulation, and dorsal root ganglion stimulation. Results are encouraging to date, and they may provide superior analgesia and cover for deficiencies of traditional tonic stimulation. Although complications are not uncommon, they are rarely life threatening or permanently disabling. Nonetheless, device removal is occasionally needed.link_to_OA_fulltex
The Legacy of Leaded Gasoline in Bottom Sediment of Small Rural Reservoirs
The historical and ongoing lead (Pb) contamination caused by the 20th-century use of leaded gasoline was investigated by an analysis of bottom sediment in eight small rural reservoirs in eastern Kansas, USA. For the reservoirs that were completed before or during the period of maximum Pb emissions from vehicles (i.e., the 1940s through the early 1980s) and that had a major highway in the basin, increased Pb concentrations reflected the pattern of historical leaded gasoline use. For at least some of these reservoirs, residual Pb is still being delivered from the basins. There was no evidence of increased Pb deposition for the reservoirs completed after the period of peak Pb emissions and (or) located in relatively remote areas with little or no highway traffic. Results indicated that several factors affected the magnitude and variability of Pb concentrations in reservoir sediment including traffic volume, reservoir age, and basin size. The increased Pb concentrations at four reservoirs exceeded the U.S. Environmental Protection Agency threshold-effects level (30.2 mg kg-1) and frequently exceeded a consensus-based threshold-effects concentration (35.8 mg kg-1) for possible adverse biological effects. For two reservoirs it was estimated that it will take at least 20 to 70 yr for Pb in the newly deposited sediment to return to baseline (pre-1920s) concentrations (30 mg kg-1) following the phase out of leaded gasoline. The buried sediment with elevated Pb concentrations may pose a future environmental concern if the reservoirs are dredged, the dams are removed, or the dams fail
Mitochondrial and nuclear markers reveal a lack of genetic structure in the entocommensal nemertean Malacobdella arrokeana in the Patagonian gulfs
Abstract Malacobdella arrokeana is an entocommensal nemertean exclusively found in the bivalve geoduck Panopea abbreviata, and it is the only representative of the genus in the southern hemisphere. To characterize its genetic diversity, population structure and recent demographic history, we conducted the first genetic survey on this species, using sequence data for the cytochrome oxidase I gene (COI), 16S rRNA (16S) and the internal transcribed spacer (ITS2). Only four different ITS2 genotypes were found in the whole sample, and the two main haplotypes identified in the mitochondrial dataset were present among all localities with a diversity ranging from 0.583 to 0.939. Nucleotide diversity was low (p = 0.001?0.002). No significant genetic structure was detected between populations, and mismatch distribution patterns and neutrality tests results are consistent with a population in expansion or under selection. Analysis of molecular variance (AMOVA) revealed that the largest level of variance observed was due to intrapopulation variation (100, 100 and 94.39 % for 16S, COI and ITS2, respectively). Fst values were also non-significant. The observed lack of population structure is likely due to high levels of genetic connectivity in combination with the lack or permeability of biogeographic barriers and episodes of habitat modification.Fil: Fernandez Alfaya, Jose Elias. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Nacional Patagónico; ArgentinaFil: Bigatti, Gregorio. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Nacional Patagónico; ArgentinaFil: Machordom, Annie. Consejo Superior de Investigaciones Cientificas. Museo Nacional de Cs. Naturales; Españ
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