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161.
Spatial patterns of trees and juveniles in a laurel forest of Tenerife, Canary Islands 总被引:5,自引:0,他引:5
Spatial patterns are important characteristics of the forest and theycan reveal such things as successional status and ecological characteristics ofthe species. We tested the hypothesis that spatial distribution will bedifferent, depending on whether the species is intolerant or tolerant to shade.We assessed the spatial distribution of trees (> 4 cm dbh) andjuveniles in eight laurel forest plots. A univariate spatial analysis(performed with Ripley's K1) showed that all tree species havesignificantaggregation at short distances (2 m). Nevertheless, two groups ofspecies could be differentiated: Erica scoparia,Myrica faya and Ilex canariensisshowed a tendency for aggregation at large distances (larger than 6m)while L. azorica and Prunuslusitanicashowed aggregation only at shorter distances. Ripley's BivariateK1,2 analyses showed no significant differences in the spatialdistribution ofanalyzed species pairs from a null model. Only Laurusazoricahad a sufficient sample size for analysis of juvenile distribution. Aunivariateanalysis revealed thatL. azorica seedlings (stems < 50 cm high)were clumped in some plots up to 5 m, but this was not consistent.Saplings (stems > 50 cm high and < 4 cm dbh)didnot show strong clumping even at short distances. L.azoricasaplings had no significant aggregation with, nor repulsionfrom, adults of the same or different species. Spatial patterns of the speciesshould be considered in the development of restoration plans of the laurelforest 90%of which has disappeared or been intensively disturbed on Tenerife Island. 相似文献
162.
Eloisa Berman Arévalo Mirjam A. F. Ros-Tonen 《Human ecology: an interdisciplinary journal》2009,37(6):733-747
While much research on forest partnerships hitherto has been focused mainly on the drivers behind their formation, the kind
of actors and deals involved, and the factors that promote or hinder their success, much less attention has been paid to the
dynamic relationships and processes inherent in these partnerships. Based on the study of a partnership process in an indigenous
reservation in Colombian Amazonia covering a variety of projects, this paper seeks to fill part of this lacuna by analyzing
the partnership as a dynamic ‘discursive battlefield,’ in which objectives and actions are being constantly negotiated. Actors
in the Matavén partnership strategically incorporate discursive elements in order to pursue their own interests while also
endorsing those that ensure the continuation of collaboration. We conclude that discourses are embedded in partnership micro-politics.
On the one hand, discursive shifts occur as a reflection of power balances at given moments. On the other hand, discourses
constitute indispensable resources with the potential to both enhance individual actor’s negotiating power and to create opportunities
for compromise. Within an ongoing discursive tension between ‘conservation’ and ‘indigenous autonomy,’ flexible notions such
as ‘territorial ordering’ prove to be successful in allowing space for manoeuvre and granting conceptual coherence to shifts
occurring ‘on the ground.’ 相似文献
163.
Savvas Genitsaris Konstantinos Ar. Kormas & Maria Moustaka-Gouni 《FEMS microbiology ecology》2009,69(1):75-83
The morphological and phylogenetic diversity of the microscopic eukaryotes of the Lake Koronia water column was investigated during a mass kill of birds and fish in August–September 2004. The dominant morphospecies corresponded to the known toxin-producing species Prymnesium parvum , followed by Amoebidium sp., a taxon belonging to the group of parasitic Mesomycetozoea , and the common chlorophyte Pediastrum boryanum. Prymnesium exhibited heteromorphic life-cycle stages (flagellate and nonmotile coccoid cells). Phylogenetic analysis with 18S rRNA gene suggested that these heteromorphic stages belonged to the Platychrysis – Prymnesium monophyletic group. The most abundant phylotype was almost identical to P. boryanum . The fungal phylotypes were related to the Chytridiomycota , and the ciliate-like ones were closely related to Enchelys polynucleata and Pattersoniella vitiphila . Two phylotypes representing novel members belonging to the Jakobida and the Apicomplexa were also found. The microscopic eukaryotes of Lake Koronia include several organisms that are related to parasitic life modes. 相似文献
164.
Raul Zamora-Ros Mireia Urpí-Sardà Rosa M. Lamuela-Raventós Ramon Estruch Miguel Ángel Martínez-González Mònica Bulló Fernando Arós Antonio Cherubini Cristina Andres-Lacueva 《Free radical biology & medicine》2009,46(12):1562-1566
Several clinical and epidemiological studies have shown that moderate wine consumption may exert a protective effect against oxidative stress involved in several diseases, such as cardiovascular and neurodegenerative disorders. However, the epidemiological assessment of wine consumption has usually been obtained using self-reported questionnaires containing less reliable information for assessing total intake than nutritional biomarkers. A reliable biomarker for wine consumption is, therefore, needed. To validate urinary resveratrol metabolites (RMs) as a biomarker of wine consumption in a large cohort of free-living subjects, 1000 consecutive subjects entering a substudy of the PREDIMED trial (Prevención con Dieta Mediterránea) were evaluated. Data were collected in a validated semiquantitative food frequency questionnaire. RMs were measured in morning urine by LC-MS/MS. Urinary RM values correlated directly with reported daily amounts of wine consumed (r = 0.895; p < 0.001). One drink of wine per week can be detected. Using a cut-off of 411.4 nmol/g creatinine, the measurement of urinary RMs could discriminate wine consumers from non-wine consumers with a sensitivity of 93.3% (95% confidence interval (CI) 91.5–94.7%) and a specificity of 92.1% (CI 90.2–93.7%). Urinary RMs fulfill the criteria to be considered as a nutritional biomarker of wine consumption in a large sample of free-living subjects. This biomarker would provide an additional tool for investigating more precisely the relationship between wine consumption and health benefits. 相似文献
165.
166.
Anna C Need Dalia Kasperavičiūtė Elizabeth T Cirulli David B Goldstein 《Genome biology》2009,10(1):R7-7
Background
It was recently shown that the genetic distinction between self-identified Ashkenazi Jewish and non-Jewish individuals is a prominent component of genome-wide patterns of genetic variation in European Americans. No study however has yet assessed how accurately self-identified (Ashkenazi) Jewish ancestry can be inferred from genomic information, nor whether the degree of Jewish ancestry can be inferred among individuals with fewer than four Jewish grandparents. 相似文献167.
Vilma Kisnierienė Vidmantas Sakalauskas Aleksandras Pleskačiauskas Vladimir Yurin Osvaldas Rukšėnas 《Central European Journal of Biology》2009,4(3):343-350
Interrelations between the action of acetylcholine (ACh) and cadmium ions (Cd2+) on bioelectrogenesis of Nitellopsis obtusa cells were investigated. We analyzed repetitively triggered action potentials (AP), their reproducibility, shape and dynamics
of membrane potential after AP induction. ACh significantly increased membrane permeability only at high concentrations (1
mM and 5 mM). Repolarisation level of action potential after the first stimulus was much more positive in all cells treated
with ACh as compared to the control. Differences of membrane potentials between points just before the first and the second
stimuli were 23.4±.0 mV (control); 40.4±5.9 mV (1 mM ACh solution) and 57.7 ± 8.5 mV (5 mM ACh solution). Cd2+ at 20 μM concentration was examined as a possible inhibitor of acetylcholinesterase (AChE) in vivo. We found that cadmium strengthens depolarizing effect of acetylcholine after the first stimulus. The highest velocity of
AP repolarization was reduced after ACh application and Cd2+strengthened this effect. There were no differences in dynamics of membrane potential after repetitively triggered action
potentials in ACh or ACh and Cd2+ solutions. This shows that cadmium in small concentration acts as inhibitor of acetylcholinesterase. 相似文献
168.
A major challenge in plant biology is to understand how functions in plant cells emerge from interactions between molecular components. Computational and mathematical modelling can encapsulate the relationships between molecular components and reveal how biological functions emerge. We review recent progress in modelling in metabolism, growth, signalling and circadian rhythms in plant cells. We discuss challenges and opportunities for future directions. 相似文献
169.
Alexander Pérez-Ruiz Margarida Julià-Sapé Guillem Mercadal Iván Olier Carles Majós Carles Arús 《BMC bioinformatics》2010,11(1):581
Background
Proton Magnetic Resonance (MR) Spectroscopy (MRS) is a widely available technique for those clinical centres equipped with MR scanners. Unlike the rest of MR-based techniques, MRS yields not images but spectra of metabolites in the tissues. In pathological situations, the MRS profile changes and this has been particularly described for brain tumours. However, radiologists are frequently not familiar to the interpretation of MRS data and for this reason, the usefulness of decision-support systems (DSS) in MRS data analysis has been explored. 相似文献170.
Sandra Ortega-Martorell Iván Olier Margarida Julià-Sapé Carles Arús 《BMC bioinformatics》2010,11(1):106