Percentage Differences (percentage + difference)

Distribution by Scientific Domains


Selected Abstracts


Responses of plants in polar regions to UVB exposure: a meta-analysis

GLOBAL CHANGE BIOLOGY, Issue 11 2009
KEVIN K. NEWSHAM
Abstract We report a meta-analysis of data from 34 field studies into the effects of ultraviolet B (UVB) radiation on Arctic and Antarctic bryophytes and angiosperms. The studies measured plant responses to decreases in UVB radiation under screens, natural fluctuations in UVB irradiance or increases in UVB radiation applied from fluorescent UV lamps. Exposure to UVB radiation was found to increase the concentrations of UVB absorbing compounds in leaves or thalli by 7% and 25% (expressed on a mass or area basis, respectively). UVB exposure also reduced aboveground biomass and plant height by 15% and 10%, respectively, and increased DNA damage by 90%. No effects of UVB exposure were found on carotenoid or chlorophyll concentrations, net photosynthesis, Fv/Fm or ,PSII, belowground or total biomass, leaf mass, leaf area or specific leaf area (SLA). The methodology adopted influenced the concentration of UVB absorbing compounds, with screens and natural fluctuations promoting significant changes in the concentrations of these pigments, but lamps failing to elicit a response. Greater reductions in leaf area and SLA, and greater increases in concentrations of carotenoids, were found in experiments based in Antarctica than in those in the Arctic. Bryophytes typically responded in the same way as angiosperms to UVB exposure. Regression analyses indicated that the percentage difference in UVB dose between treatment and control plots was positively associated with concentrations of UVB absorbing compounds and carotenoids, and negatively so with aboveground biomass and leaf area. We conclude that, despite being dominated by bryophytes, the vegetation of polar regions responds to UVB exposure in a similar way to higher plant-dominated vegetation at lower latitudes. In broad terms, the exposure of plants in these regions to UVB radiation elicits the synthesis of UVB absorbing compounds, reduces aboveground biomass and height, and increases DNA damage. [source]


Women with Pain due to Osteoarthritis: The Efficacy and Safety of a Once-Daily Formulation of Tramadol

PAIN MEDICINE, Issue 6 2009
FRCP, Walter F. Kean MB ChB
ABSTRACT Objective., This analysis assesses the efficacy and safety of treatment with a once-daily oral formulation of tramadol for up to 12 weeks compared with placebo in women with moderate-to-severe pain due to osteoarthritis of the knee. Design., Two parallel, placebo-controlled phase III clinical trials were analyzed; patients were randomized to a fixed dosage of Tramadol Contramid® once a day (OAD) 100, 200, and 300 mg daily, or placebo. Outcome Measures., The primary efficacy end points were the percentage difference from baseline of the Western Ontario and McMaster University Osteoarthritis Index (WOMAC) subscale scores for pain and physical function, and the patient global rating of pain relief after 12 weeks of maintenance therapy. Results., The analysis included 405 women receiving tramadol and 280 receiving placebo. At week 12, 179 of 204 women (87.7%) receiving tramadol rated their overall pain relief as effective or very effective compared with 134 of 177 (75.7%) receiving placebo. A time-weighted analysis revealed statistically significant improvements over placebo for all the WOMAC subscale scores across all three dosages. The percentage improvements from baseline of the WOMAC pain scores were significantly better than placebo for the 100-mg (58.8 ± 37.1%, P = 0.018) and 300-mg (58.9 ± 38.8%, P = 0.023) treatment arms; however, the 200-mg dosage was not significant (53.0 ± 38.5%, P = 0.175). The WOMAC physical function scores showed significant improvement for the 100 (56.9 ± 36.4%, P = 0.009), 200 (54.0 ± 33.8%, P = 0.034), and 300 mg (53.4 ± 41.4%, P = 0.043) daily dosages. Conclusion., For moderate-to-severe pain due to osteoarthritis of the knee, women experience significant analgesia and improvement of physical function over time with treatment with Tramadol Contramid® OAD. [source]


Internationalizing the Broselow Tape: How Reliable Is Weight Estimation in Indian Children

ACADEMIC EMERGENCY MEDICINE, Issue 5 2008
Naresh Ramarajan AB
Abstract Objectives:, The Broselow pediatric emergency weight estimation tape is an accurate method of estimating children's weights based on height,weight correlations and determining standardized medication dosages and equipment sizes using color-coded zones. The study objective was to determine the accuracy of the Broselow tape in the Indian pediatric population. Methods:, The authors conducted a 6-week prospective cross-sectional study of 548 children at a government pediatric hospital in Chennai, India, in three weight-based groups: <10 kg (n = 175), 10,18 kg (n = 197), and >18 kg (n = 176). Measured weight was compared to Broselow-predicted weight, and the percentage difference was calculated. Accuracy was defined as agreement on Broselow color-coded zones, as well as agreement within 10% between the measured and Broselow-predicted weights. A cross-validated correction factor was also derived. Results:, The mean percentage differences were ,2.4, ,11.3, and ,12.9% for each weight-based group. The Broselow color-coded zone agreement was 70.8% in children weighing less than 10 kg, but only 56.3% in the 10- to 18-kg group and 37.5% in the >18-kg group. Agreement within 10% was 52.6% for the <10-kg group, but only 44.7% for the 10- to 18-kg group and 33.5% for the >18-kg group. Application of a 10% weight-correction factor improved the percentages to 77.1% for the 10- to 18-kg group and 63.0% for the >18-kg group. Conclusions:, The Broselow tape overestimates weight by more than 10% in Indian children >10 kg. Weight overestimation increases the risk of medical errors due to incorrect dosing or equipment selection. Applying a 10% weight-correction factor may be advisable. [source]


Cerebral vasomotor reactivity of bilateral severe carotid stenosis: is stroke unavoidable?

EUROPEAN JOURNAL OF NEUROLOGY, Issue 2 2006
A. Y. Gur
We evaluated the cerebral hemodynamic features of severe bilateral carotid stenosis by assessing and comparing cerebral vasomotor reactivity (VMR) in the middle cerebral (MCA) and vertebral arteries (VA) by transcranial Doppler and the Diamox (1 g acetazolamide i.v.) test. VMR was evaluated by recording the percentage differences in peak systolic blood flow velocity in each MCA and VA at baseline and by the Diamox test. Twenty-eight symptomatic (SCAS) and 31 asymptomatic (ACAS) patients with bilateral severe (>70%) internal carotid artery stenosis were studied. The mean MCA VMR% was 29 ± 26.9% in SCAS and 43.2 ± 26.8% in ACAS patients (P < 0.01). Their respective mean VA VMR% was 30.2 ± 36.5% and 39.6 ± 24.4% (P = NS). VMR% of the symptomatic MCA side in SCAS patients was significantly lower than the opposite side (20.5 ± 31.1% and 39.2 ± 37.9% respectively; P < 0.03). In contrast, the VA VMR% of both sides in SCAS patients remained similar (28.1 ± 39.3% and 34.6 ± 47.9% respectively; P = NS). VMR% of the MCA and VA in ACAS patients was also similar for both sides of bilateral carotid stenosis. The cerebral hemodynamic features differ between SCAS and ACAS patients with bilateral carotid occlusive disease in the anterior part of the circle of Willis. An independent cerebral vascular reserve capacity of the posterior circulation is proposed. [source]


Technical note: The effect of midshaft location on the error ranges of femoral and tibial cross-sectional parameters

AMERICAN JOURNAL OF PHYSICAL ANTHROPOLOGY, Issue 2 2010
Vladimír Sládek
Abstract In comparing long-bone cross-sectional geometric properties between individuals, percentages of bone length are often used to identify equivalent locations along the diaphysis. In fragmentary specimens where bone lengths cannot be measured, however, these locations must be estimated more indirectly. In this study, we examine the effect of inaccurately located femoral and tibial midshafts on estimation of geometric properties. The error ranges were compared on 30 femora and tibiae from the Eneolithic and Bronze Age. Cross-sections were obtained at each 1% interval from 60 to 40% of length using CT scans. Five percent of deviation from midshaft properties was used as the maximum acceptable error. Reliability was expressed by mean percentage differences, standard deviation of percentage differences, mean percentage absolute differences, limits of agreement, and mean accuracy range (MAR) (range within which mean deviation from true midshaft values was less than 5%). On average, tibial cortical area and femoral second moments of area are the least sensitive to positioning error, with mean accuracy ranges wide enough for practical application in fragmentary specimens (MAR = 40,130 mm). In contrast, tibial second moments of area are the most sensitive to error in midshaft location (MAR = 14,20 mm). Individuals present significant variation in morphology and thus in error ranges for different properties. For highly damaged fossil femora and tibiae we recommend carrying out additional tests to better establish specific errors associated with uncertain length estimates. Am J Phys Anthropol 2010. © 2009 Wiley-Liss, Inc. [source]


The Price Premium of China A-Shares over Hong Kong H-Shares: A Further Visit of the Liquidity Hypothesis,

ASIA-PACIFIC JOURNAL OF FINANCIAL STUDIES, Issue 5 2009
Hing-Wah Lee
Abstract I examine the price premium between A-shares and H-shares using a sample of Hong Kong, Shenzhen, and Shanghai stock market intraday data in 2004. Following the market-microstructure approach, I reinvestigate the liquidity hypothesis by incorporating spread and depth. The study generates two important results. First, China A-shares on average provide better market liquidity than their Hong Kong H-share counterparts do. Second, after controlling for traditional liquidity measures and variables related to competing hypotheses, the percentage differences in quoted spread and depth between A-shares and H-shares still explain significantly the price premium. Endogeneity between spread and depth does not affect the major findings. [source]


Structure Elucidation and Phytotoxicity of Ecdysteroids from Chenopodium album

CHEMISTRY & BIODIVERSITY, Issue 4 2005
Marina DellaGreca
The leaves of Chenopodium album were infused in H2O/MeOH. The extract treated with cold acetone gave heavy precipitation, which was removed by centrifugation. Solid material was fractionated into acidic and neutral fractions. The acidic material was subjected to different silica-gel column chromatographies, and then it was purified by reversed-phase HPLC to afford four known ecdysteroids and the new 3,,14, -dihydroxy-5, -pregn-7-ene-2,6,20-trione that were characterized by extensive spectroscopic investigation, especially by 1D- and 2D-NMR. Their effects on germination and growth of Lactuca sativa L. have been studied. The results are reported as percentage differences of germination, root elongation and shoot elongation, from the control at concentrations ranging from 10,4 to 10,7,M. [source]


Chenoalbicin, a Novel Cinnamic Acid Amide Alkaloid from Chenopodium album

CHEMISTRY & BIODIVERSITY, Issue 10 2004
Francesca Cutillo
The roots of Chenopodium album were infused in MeOH, and the extract was partitioned between AcOEt and H2O. AcOEt-Soluble material was subjected to different silica-gel column chromatographies and then purified by reverse-phase HPLC to afford a new cinnamic acid amide alkaloid as a racemic mixture. The new compound, named chenoalbicin (1), was characterized by extensive spectroscopic investigation, especially 1D and 2D NMR spectroscopy. Its effects on the germination and growth of Lactuca sativa L. has been studied. The results are reported as percentage differences of germination, root elongation, and shoot elongation from the control at concentrations ranging from 10,4 to 10,7,M. [source]