Home About us Contact
|
Home About us Contact | ||
|
|
||
Scarce Information (scarce + information)
Selected AbstractsEstimating Canopy Structure in an Amazon Forest from Laser Range Finder and IKONOS Satellite Observations,BIOTROPICA, Issue 4 2002Gregory P. Asner ABSTRACT Canopy structural data can be used for biomass estimation and studies of carbon cycling, disturbance, energy balance, and hydrological processes in tropical forest ecosystems. Scarce information on canopy dimensions reflects the difficulties associated with measuring crown height, width, depth, and area in tall, humid tropical forests. New field and spaceborne observations provide an opportunity to acquire these measurements, but the accuracy and reliability of the methods are unknown. We used a handheld laser range finder to estimate tree crown height, diameter, and depth in a lowland tropical forest in the eastern Amazon, Brazil, for a sampling of 300 trees stratified by diameter at breast height (DBH). We found significant relationships between DBH and both tree height and crown diameter derived from the laser measurements. We also quantified changes in crown shape between tree height classes, finding a significant but weak positive trend between crown depth and width. We then compared the field-based measurements of crown diameter and area to estimates derived manually from panchromatic 0.8 m spatial resolution IKONOS satellite imagery. Median crown diameter derived from satellite observations was 78 percent greater than that derived from field-based laser measurements. The statistical distribution of crown diameters from IKONOS was biased toward larger trees, probably due to merging of smaller tree crowns, underestimation of understory trees, and overestimation of individual crown dimensions. The median crown area derived from IKONOS was 65 percent higher than the value modeled from field-based measurements. We conclude that manual interpretation of IKONOS satellite data did not accurately estimate distributions of tree crown dimensions in a tall tropical forest of eastern Amazonia. Other methods will be needed to more accurately estimate crown dimensions from high spatial resolution satellite imagery. [source] Archeology and written sources on eighth- to tenth-century BohemiaEARLY MEDIEVAL EUROPE, Issue 3 2009'a Profantová This article examines the contribution of archaeology to our understanding of the history of Bohemia in the early Middle Ages. In a period for which only scarce information is available from written sources, archaeology is able to verify information from legend and confirm the scanty written evidence. The results of archaeological research, however, also strongly suggest that relations between Bohemians and Magyars were much more complex than the evidence of the written sources has until now led many to believe. [source] Evaluation of a novel Bacillus strain from a north-western Spain hot spring as a source of extracellular thermostable lipaseJOURNAL OF CHEMICAL TECHNOLOGY & BIOTECHNOLOGY, Issue 10 2009Francisco J. Deive Abstract BACKGROUND: Thermophilic microorganisms are receiving significant attention as a source of useful thermostable enzymes. However, the number of known strains is still limited, and very often their most interesting biocatalysts are intracellular or membrane-bound and produced at low levels. Thus, the isolation and study of novel extracellular enzyme-producing thermophilic microorganisms is very interesting. Moreover, the assessment of bioreactor performance is crucial, given the scarce information on the large-scale culture of these strains. RESULTS: The production of a thermostable extracellular lipase in submerged cultures of a thermophilic microorganism, recently isolated in north-west Spain, was investigated. The strain was identified by 16S rDNA sequencing as belonging to genus Bacillus. The influence of operating variables (i.e. pH, temperature, aeration) on lipase biosynthesis was analysed. Enzyme production at bioreactor scale was investigated, special attention being paid to the effect of aeration and agitation rates. CONCLUSION: The best conditions for the studied process were determined in shake flasks as pH 7.0, 55 °C and high aeration levels. Also, the non-association between lipase production and cell growth was ascertained. The culture of this novel strain was successfully carried out in laboratory-scale bioreactors, thus proving its potential for further applications. Copyright © 2009 Society of Chemical Industry [source] Relative frequency of peripheral odontogenic tumors: a study of 45 new cases and comparison with studies from the literatureJOURNAL OF ORAL PATHOLOGY & MEDICINE, Issue 7 2006Amos Buchner Background:, Peripheral (extraosseous) odontogenic tumors are rare, and reports in the literature have mainly been single case reports or a small series of cases. The aim of this study was to determine the relative frequency of peripheral (extraosseous) odontogenic tumors relative to one another and relative to their central (intraosseous) counterparts in an oral pathology biopsy service and to compare these data with information available in the literature. Methods:, The files of the Pacific Oral and Maxillofacial Pathology Laboratory of the University of the Pacific, San Francisco, CA, USA, served as the source of material for this study. Files were systematically searched for all cases of peripheral odontogenic tumors (POTs) during a 20-year-period. Results:, There were 91 178 cases accessed in which central and POTs were identified in 1133 (1.24%), central tumors in 1088 (1.2%), and peripheral tumors in 45 (0.05%). Peripheral tumors accounted for 4% of all 1133 central and POTs. Peripheral odontogenic fibroma (PODF) was the most common of the 45 POTs accounting for 51.1% (23 cases) followed by peripheral ameloblastoma (PA) 28.9% (13 cases) and peripheral calcifying cystic odontogenic tumor (PCCOT) 13.3% (six cases). Peripheral calcifying epithelial odontogenic tumor, peripheral ameloblastic fibroma, and peripheral ameloblastic carcinoma were also identified , each comprised 2.2% (one case each). PODF was more common than its central counterpart by a 1.4:1 ratio. This was the only peripheral tumor that was more common than its central counterpart. PA accounted for 9.3% of all ameloblastomas and PCCOT for 26% of all calcifying cystic odontogenic tumors. Conclusion:, There is only scarce information in the literature on the relative frequency of POTs. Additional studies should be conducted to determine the true relative frequency. To ensure accuracy, pathologists with experience in the field of odontogenic tumors should conduct these studies. Intraosseous tumors that perforate through the bone to the gingival tissue, clinically presenting as ,peripheral tumors' should be excluded. [source] Pulmonary mucus: Pediatric perspectivePEDIATRIC PULMONOLOGY, Issue 3 2003Duncan F. Rogers PhD Abstract Airway mucus hypersecretion is a clinical feature of a number of childhood diseases, including asthma and bronchitis-associated conditions. However, compared with adults, there is relatively scarce information concerning mucus pathophysiology in respiratory diseases in children. The available evidence indicates many similarities between adult and childhood respiratory hypersecretory conditions, including goblet-cell hyperplasia and submucosal gland hypertrophy, and airway mucus plugging in asthma. Consequently, it is likely that treatments that are effective in adults would be effective in children. Numerous therapeutic targets are linked to the pathophysiology of airway mucus hypersecretion in experimental models and adults with respiratory disease. Whether or not these same targets are relevant in children is for the most part unclear. These targets include the inflammatory cells mediating the inflammatory response that generates the hypersecretory phenotype, and highly specific cellular elements such as epidermal growth factor receptor tyrosine kinase and calcium-activated chloride (CACL) channels. Identification of these factors is linked with the development of different classes of pharmacotherapeutic molecules directed at these targets. Compounds with a broader spectrum of anti-inflammatory activity are likely to be more effective than compounds with restricted activity. However, certain highly specific targets, such as human CACL1 channels, appear to be strongly associated with the development of an airway hypersecretory phenotype. Data from current clinical trials in adults with blockers of these specific targets are awaited with great interest. The hope is that, if effective, pediatric trials with these compounds could be initiated with a view to alleviation of the clinical impact of airway mucus hypersecretion in children. A significant challenge to the therapeutic progression of these new compounds is effective delivery to the airways in children, with the research effort into development of new compounds matched by advances in inhaler design. Pediatr Pulmonol. 2003; 36:178,188. © 2003 Wiley-Liss, Inc. [source] A well-characterised peak identification list of MALDI MS profile peaks for human blood serumPROTEINS: STRUCTURE, FUNCTION AND BIOINFORMATICS, Issue 18 2010Ali Tiss Abstract MALDI MS profiling, using easily available body fluids such as blood serum, has attracted considerable interest for its potential in clinical applications. Despite the numerous reports on MALDI MS profiling of human serum, there is only scarce information on the identity of the species making up these profiles, particularly in the mass range of larger peptides. Here, we provide a list of more than 90 entries of MALDI MS profile peak identities up to 10,kDa obtained from human blood serum. Various modifications such as phosphorylation were detected among the peptide identifications. The overlap with the few other MALDI MS peak lists published so far was found to be limited and hence our list significantly extends the number of identified peaks commonly found in MALDI MS profiling of human blood serum. [source] Can soil seed banks contribute to the restoration of dune slacks under conservation management?APPLIED VEGETATION SCIENCE, Issue 2 2009Katharina Plassmann Abstract Questions: Does the soil seed bank resemble the former early successional stages of a dune slack system more than the established later successional vegetation? Does it have the potential to contribute to the conservation of a highly endangered habitat? Location: Dune slacks at Newborough Warren, UK. Methods: The composition of the soil seed bank in two depth layers was determined using the seedling emergence method between March 2004 and April 2005. Long-term monitoring data on the floristic composition of the established vegetation were obtained from the national conservation agency, and additional monitoring was undertaken in 2003. Floristic composition, seed weights, seed longevity of component species and Ellenberg indicator values were used to compare the seed bank and established vegetation. Results: The soil seed bank was diverse and contained typical dune slack species, species of early successional stages and species of conservation interest. A comparison between the composition of the seed bank and historical data on the composition of the established vegetation showed that the seed bank reflects earlier successional stages more closely than the current aboveground vegetation. This study increases the scarce information currently available on the seed bank ecology of several species, including two orchid species. Conclusions: The soil seed bank can be expected to contribute to vegetation change after disturbance. Stimulation of germination from the seed bank through management may contribute to the conservation of both characteristic and threatened species typical of dune slacks. [source] Linking frugivore activity to early recruitment of a bird dispersed tree, Eugenia umbelliflora (Myrtaceae) in the Atlantic rainforestAUSTRAL ECOLOGY, Issue 3 2009MARINA CORRÊA CÔRTES Abstract Seed dispersal by animals is a complex process involving several distinct stages: fruit removal by frugivores, seed delivery in different microhabitats, seed germination, seedling establishment, and adult recruitment. Nevertheless, studies conducted until now have provided scarce information concerning the sequence of stages in a plant's life cycle in its entirety. The main objective of this study was to evaluate the immediate consequences of frugivore activity for Eugenia umbelliflora (Myrtaceae) early recruitment by measuring the relative importance of each fruit-eating bird species on the establishment of new seedlings in scrub and low restinga vegetation in the Atlantic rainforest, Brazil. We conducted focal tree observations on E. umbelliflora trees recording birds' feeding behaviour and post-feeding movements. We also recorded the fate of dispersed seeds in scrub and low restinga vegetation. We recorded 17 bird species interacting with fruits in 55 h of observation. Only 30% of the handled fruits were successfully removed. From 108 post flight movements of exit from the fruiting trees, 30.6% were to scrub and 69.4% to low restinga forest. Proportion of seed germination was higher in low restinga than in the scrub vegetation. Incorporating the probabilities of seeds' removal, deposition, and germination in both sites, we found that the relative importance of each frugivorous bird as seed dispersers varies largely among species. Turdus amaurochalinus and Turdus rufiventris were the best dispersers, together representing almost 12% probability of seed germination following removal. Our results show the importance of assessing the overall consequence of seed dispersal within the framework of disperser effectiveness, providing a more comprehensive and realistic evaluation of the relative importance of different seed dispersers on plant population dynamics. [source] Grapevine genetics after the genome sequence: Challenges and limitationsAUSTRALIAN JOURNAL OF GRAPE AND WINE RESEARCH, Issue 2010J.M. MARTÍNEZ-ZAPATER Abstract The publication of the genome sequences of inbred grapevine plant PN40024 and the cultivar Pinot Noir has provided a new generation of molecular tools and has opened the way to functional genomics in grapevine. Establishing gene biological function is now a major challenge requiring the parallel development of molecular and genetic information. New massive pyrosequencing technologies will ensure no shortage of nucleotide sequence information. However, genetic analysis and genetic tools in grapevine still require additional development. Exploiting the existing natural genetic variation in Vitis vinifera L. and other inter-fertile Vitis species should be a priority to focus functional analyses on genes contributing to phenotypic variation because their genetic variation constitutes the basis for genetic improvement of classical cultivars and for the development of new ones. In this review, we discussed the current molecular and genetic tools available in grapevine and considered those that need to be developed to exploit natural genetic variation in the analyses of gene function. We also reviewed the scarce information on the genetic and molecular structure of relevant grapevine traits and proposed future directions. [source] Synthesis and analysis of aminochromes by HPLC-photodiode array.BIOMEDICAL CHROMATOGRAPHY, Issue 1 2003Adrenochrome evaluation in rat blood Abstract The catecholamine oxidation process induces cardiotoxicity and neurotoxicity. Catecholamines can oxidize to aminochromes through autoxidation or by enzymatic or non-enzymatic catalysis. Although some toxic effects seem to be related to the formation of aminochromes there is still scarce information concerning the identification and evaluation of these compounds in in vivo models. In this study five catecholamines were oxidized to their respective aminochromes: adrenaline/adrenochrome; noradrenaline/noradrenochrome; dopa/dopachrome; dopamine/dopaminochrome; and isoproterenol/isoprenochrome. The evaluation of the catecholamines oxidation profile was performed by HPLC with photodiode array detection and using either enzymatic (tyrosinase) or non-enzymatic [Ag2O, CuSO4, NaIO4 and K3Fe(CN)6] catalytic systems. The NaIO4 was found to be the most efficient oxidant of catecholamines. An isocratic reverse-phase HPLC method was developed to analyse each pair of catecholamine,aminochrome. The analytical system was then applied to the detection of adrenochrome in rat blood at 490,nm. Thus, adrenochrome was administered i.p. to rats and its concentration in whole blood was monitored after 5, 15 and 25,min. Blood treatment for adrenochrome evaluation consists of an acidification for protein precipitation followed by a rapid neutralization. The results showed a rapid decrease of adrenochrome concentration in blood after its administration. The adrenochrome present in blood was characterized by UV and tandem mass spectrometry. Copyright © 2002 John Wiley & Sons, Ltd. [source] Carotid Stenosis as Detected by Ultrasound in a General Population is a Strong Predictor of DeathACTA NEUROLOGICA SCANDINAVICA, Issue 5 2001Oddmund Joakimsen Background and Purpose: In the last two decades, ultrasound examinations have increasingly been used as a noninvasive method to screen for carotid stenosis. Several clinical studies have shown that carotid stenosis is a risk factor for ischemic stroke and coronary heart disease and death. However, there is scarce information about stenosis as detected in a general population and the relation with mortality. The purpose of this population-based study was to assess whether carotid stenosis is a predictor of death. Methods: In 1994 to 1995, 248 subjects with suspected carotid stenosis were identified among 6727 men and women 25 to 84 years of age who were examined with ultrasound as part of the population-based Tromsø Study. These subjects and 496 age- and sex-matched control subjects were followed for 4.2 years, and the number and causes of deaths were identified. Results: The unadjusted relative risk for death was 2.72 (95% CI, 1.57 to 4.75) for subjects with stenosis compared with control subjects. Adjusting for cardiovascular risk factors increased the relative risk to 3.47 (95% CI, 1.47 to 8.19). The adjusted relative risk in persons with stenosis and no cardiovascular disease or diabetes was 5.66 (95% CI, 1.53 to 20.90), which was higher than in subjects with stenosis and self-reported disease (1.79; 95% CI, 0.75 to 4.27). There was a dose-response relationship between degree of stenosis and risk of death (P=0.002 for linear trend). Conclusion: Carotid stenosis as detected in a general population is a strong and independent predictor of death. Carotid stenosis was a stronger predictor of death than self-reported cardiovascular disease or diabetes. [source] The psychological impact of genital anomalies on the parents of affected childrenACTA PAEDIATRICA, Issue 3 2007A Duguid Abstract Background: There is scarce information on how parents cope with children with genital anomalies. Participants & methods: Twenty-six parents of 25 children with a median age of 0.5 years (r, 5 days,10.8 years) were recruited through the Scottish Genital Anomaly Network and had a quantitative assessment of parenting stress and coping patterns; a qualitative assessment by a semi-structured interview was also performed in19 parents. Results: In five parents, the total stress score was above the 85th centile, denoting clinical levels of stress. Three parents showed reduced coping pattern scores for social support, self-esteem and psychological stability and three showed a reduction in utilization of communication with medical professionals. The scores did not correlate with each other or the extent of genital anomaly in the child. Semi-structured interview analysis revealed parents' need for more knowledge about the imminent surgery, post-operative care and their desire for written information that could complement the time-restricted contact with the clinical team. Conclusion: In the majority of cases, parents did not display abnormal levels of stress or coping on quantitative assessment. The semi-structured interview provided further information about the parents' level of coping and potential for stress and highlighted the need for more effective exchange of clinical information at a critical period of the parent,child relationship. [source] Stroke in renal transplant recipients: epidemiology, predictive risk factors and outcomeCLINICAL TRANSPLANTATION, Issue 1 2003Anna Oliveras Abstract: Background:, Cerebrovascular and cardiovascular diseases are the most important causes of increased morbidity and mortality in patients with end-stage renal disease. Stroke has been widely reported in chronic dialysis patients, but there is scarce information about stroke in renal transplant recipients (RTR), although cerebrovascular events are the most common and potentially life-threatening neurological complications in them. Our aim is to analyze the prevalence, risk factors, etiopathogenia, clinical aspects and outcome of stroke in RTR. Methods:, We analyzed 403 patients who received one or more renal grafts between 1979 and 2000: group A = patients who had stroke (n = 19); group B = those who did not (n = 384). Medical records and pertinent data were compiled. The risk of stroke was studied using univariate and multivariate Cox regression models. Results:, prevalence of stroke in RTR was 7.97% at 10 yr. Time elapsed between renal transplantation (RT) and stroke: 49.3 months. Possible risk factors based on the univariate analyses were: diabetic nephropathy (DN) (p <,0.001) and autosomal-dominant-polycystic-kidney-disease (p =,0.049) as original nephropathies, peripheral vascular disease (PVD) (p <,0.001), diabetes mellitus prior to RT (p =,0.005), age older than 40 yr (p =,0.037) and hypertension (p =,0.049). Other analysed risk factors such as gender, renal function, cytomegalovirus infection, hyperlipidemia, hyperuricemia, erythrocytosis or hypertensive donor failed to show any significant predictive value for stroke in these patients. When multivariate analyses were carried out, we found that DN (OR = 4.8; p = 0.010), PVD (OR = 8.2; p < 0.001) and age > 40 yr (OR = 3.3; p = 0.019) were predictive risk factors for stroke. For group A, hypertension was present in all patients, 68.4% had hyperlipidemia and 42.1% reported previous stroke. Cerebral hemorrhage occurred in seven of 19 (36.84%) of the stroke patients, but no subarachnoid hemorrhage occurred in them. Seven of 12 ischemic strokes were atherotrombotic. Considering all strokes, basal ganglia was the predominant localization. The outcome was poor, as nearly half of the patients died in the 3 months following stroke. Conclusions:, Prevalence of stroke in our RTR population was 7.97%. Cerebral hemorrhage appears to be more prevalent in RTR than in general population. More than that, the cerebral hemorrhage rate we found is higher than that reported elsewhere in RTR. The main predictors of stroke were DN, PVD and age. No patient with interstitial nephropathy suffered stroke. Mortality is high in RTR with stroke. [source] | ||||||||||||||||