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Common Variables (common + variable)

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Medical Sciences60%

Terms modified by Common Variables

  • common variable immunodeficiency
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    Selected Abstracts

    Allometric Models for Tree Volume and Total Aboveground Biomass in a Tropical Humid Forest in Costa Rica1

    BIOTROPICA, Issue 1 2005
    Milena Segura
    ABSTRACT Allometric equations for the estimation of tree volume and aboveground biomass in a tropical humid forest were developed based on direct measurements of 19 individuals of seven tree species in Northern Costa Rica. The volume and the biomass of the stems represented about two-thirds of the total volume and total aboveground biomass, respectively. The average stem volume varied between 4 and 11 Mg/tree and the average total aboveground biomass ranged from 4 to 10 mg/tree. The mean specific gravity of the sampled trees was 0.62 ± 0.06 (g/cm3). The average biomass expansion factor was 1.6 ± 0.2. The best-fit equations for stem and total volume were of logarithmic form, with diameter at breast height (R2= 0.66 , 0.81) as an independent variable. The best-fit equations for total aboveground biomass that were based on combinations of diameter at breast height, and total and commercial height as independent variables had R2 values between 0.77 and 0.87. Models recommended for estimating total aboveground biomass are based on diameter at breast height, because the simplicity of these models is advantageous. This variable is easy to measure accurately in the field and is the most common variable recorded in forest inventories. Two widely used models in literature tend to underestimate aboveground biomass in large trees. In contrast, the models developed in this study accurately estimate the total aboveground biomass in these trees. RESUMEN Ecuaciones alométricas para la estimación de volumen y biomasa aérea de árboles en un bosque húmedo tropical fueron desarrollados basados en mediciones directas de 19 individuos de siete especies de árboles al norte de Costa Rica. El volumen y la biomasa del tronco representaron cerca de dos terceras partes del volumen total del árbol y de la biomasa aérea total. El volumen promedio del tronco varió entre 4 y 11 Mg/árbol y el promedio de la biomasa aérea total varió entre 4 y 10 mg/árbol. La gravedad específica promedio de los árboles muestreados fué de 0.62 ± 0.06 (g/cm3). El factor de expansión de biomasa promedio fué de 1.6 ± 0.2. Las ecuaciones de mejor ajuste para el volumen de tallo y total fueron de tipo logarítmico, con el diámetro a la altura de pecho (R2= 0.66 a 0.81) como variable independiente. Las ecuaciones de mejor ajuste para biomasa aérea total, las cuales fueron basadas en combinaciones de diámetro a la altura de pecho y altura total y comercial como variables independientes, presentaron valores de R2 entre 0.77 y 0.87. Los modelos recomendados para estimar biomasa aérea total están basados en diámetro a la altura de pecho, porque la simplicidad de estos modelos es ventajosa. Esta variable es de fácil medición en el campo y tiene mayor precision, además, es la más comúnmente registrada en inventarios forestales. Dos modelos ampliamente usados en la literature tienden a subestimar la biomasa aérea total en árboles grandes. En contraste, los modelos desarrollados en este estudio, estiman con mayor precisión la biomasa aérea total de estos árboles. [source]

    The prognosis of occupational contact dermatitis in 2004

    CONTACT DERMATITIS, Issue 5-6 2004
    Jennifer Cahill
    The prognosis of occupational contact dermatitis (OCD) takes into account the extent of healing, effect on quality of life and employment, and financial costs for both the individual and the wider community. We reviewed 15 studies published between 1958 and 2002, reporting the complete clearance of dermatitis (range of 18,72%). 9 of the 15 studies reported a clearance rate of between 18 and 40%. Improvement was reported as an outcome in 3 studies between 1991 and 2002 (range of 70,84%). A number of common variables were identified as of possible influence. These include age, sex, atopy, patient knowledge, disease aetiology, duration of symptoms and job change; clinical, financial and social issues are also described. All of these factors need to be considered when managing a patient with OCD. Improved patient knowledge and early diagnosis may be associated with improved prognosis, whereas job change does not make a significant difference. Some patients will develop persistent post-occupational dermatitis, which has important implications for prognosis and workers' compensation. Only a small proportion of eligible patients receive workers' compensation, even though financially supported healing time soon after diagnosis may result in an improved prognosis. [source]

    Factors affecting recruitment of glass eels into the Grey River, New Zealand

    JOURNAL OF FISH BIOLOGY, Issue 5 2003
    D. J. Jellyman
    The arrival pattern of glass eels of the shortfin eel Anguilla australis and longfin eel Anguilla dieffenbachii was studied over a two successive migration seasons in the Grey River, South Island, New Zealand. Fishing was carried out on selected nights during September to November, for 3 h per night during 2000 and 2001. The number of shortfin glass eels exceeded longfins in both years; earliest glass eels (September) were larger than later glass eels (November), and longfins larger than shortfins, but there were significant differences in size between years for both species. Environmental variables affecting recruitment differed between years, but common variables for both years were sampling date, time after high tide (incoming tide preferred), time after sunset and moon phase; the influence of moon phase appeared to be expressed both through tides (spring tides preferred) and moonlight. During the year of higher discharge variability, both increasing discharge and increased turbidity were also important. [source]

    Predicting behavioral problems in craniopharyngioma survivors after conformal radiation therapy

    PEDIATRIC BLOOD & CANCER, Issue 7 2009
    Eugenia P. Dolson BS
    Abstract Background Although radiation therapy is a primary treatment for craniopharyngioma, it can exacerbate existing problems related to the tumor and pre-irradiation management. Survival is often marked by neurologic deficits, panhypopituitarism, diabetes insipidus, cognitive deficiencies, and behavioral and social problems. Procedure The Achenbach Child Behavior Checklist (CBCL) was used to evaluate behavioral and social problems during the first 5 years of follow-up in 27 patients with craniopharyngioma treated with conformal radiation therapy. Results All group averages for the CBCL scales were within the age-typical range at pre-irradiation baseline. Extent of surgical resection was implicated in baseline differences for the internalizing, externalizing, behavior problem and social scores. Significant longitudinal changes were found in internalizing, externalizing, behavior problem and school scores that correlated with tumor and treatment-related factors. Conclusions The most common variables implicated in post-irradiation behavioral and social problems were CSF shunting, presence of an Ommaya reservoir, diabetes insipidus, and low pre-irradiation growth hormone levels. Pediatr Blood Cancer 2009;52:860,864. © 2009 Wiley-Liss, Inc. [source]

    Changing risk factors for fluorosis among South Australian children

    COMMUNITY DENTISTRY AND ORAL EPIDEMIOLOGY, Issue 3 2008
    A. John Spencer
    Abstract,,, Background:, Research in the last decade has shown changing exposure patterns to discretionary fluorides and declining prevalence of fluorosis among South Australian children, raising the question of how risk factors for fluorosis have changed. Objective:, To examine and compare risk factors for fluorosis among representative samples of South Australian children in 1992/1993 and 2002/2003. Methods:, Similar sampling strategies and data collection methods were employed in the Child Fluoride Study (CFS) Marks 1 (1992/1993) and 2 (2002/2003). Participants in each CFS round were examined for fluorosis using the Thylstrup and Fejerskov (TF) Index. Exposure history was collected for fluoride in water, toothpaste, fluoride supplements and infant formula, allowing for a fluorosis risk assessment analysis. Data were re-weighted to represent the child population at each time. Changes in prevalence of fluorosis, defined as having a TF score of 1+ on maxillary central incisors, fluoride exposure and risk factors between the two rounds were evaluated. Result:, A total of 375 and 677 children participated in the 1992/1993 and 2002/2003 rounds respectively. Prevalence of fluorosis declined significantly from 45.3% to 25.9%. Reduced use of fluoride supplements and increased use of 400,550-ppm children F toothpaste were the most substantial fluoride exposure changes. Early toothpaste use, residence in fluoridated areas and fluoride supplement use were the risk factors in 1992/1993. Early toothpaste use and fluoride supplement use were not risk factors, leaving fluoridated water as the only risk factor among the common variables in 2002/2003. In an analysis stratified by the type of fluoridated toothpaste in 2002/2003, the large amount of toothpaste used was a risk factor in those who used 1000-ppm fluoridated toothpaste, and eating/licking toothpaste when toothpaste use started was a risk factor among children who used either 1000-ppm or 400,550-ppm fluoridated toothpaste. Conclusion:, Introduction of the 400,550-ppm F toothpaste and use of smaller amount of toothpaste restricted risk associated with early toothpaste use. Less use and possibly a stricter fluoride supplements regimen also restricted fluorosis risk. Periodic monitoring of risk of fluorosis is required to adjust guidelines for fluoride use in caries prevention. [source]