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PubMed1999

Cell death mechanisms in the olfactory bulb of rats infected intranasally with Semliki forest virus.

Semliki Forest virus (SFV) infection of mice is used as a model to study pathogenic processes occurring in viral encephalitis. It has previously been shown that avirulent strains of SFV differ from virulent strains in showing restricted multiplication in neurones and in producing localized rather than widespread lesions in the central nervous system (CNS). Restricted neuronal damage is age-dependent and does not occur in neonatal animals. In this study, cell death mechanisms occurring in the CNS of adult rats infected intranasally (i.n.) with a virulent (SFV4) and an avirulent (A7) strain of SFV have been investigated. Although i.n. infection of rats was less efficient than that of mice, SFV4 reached a higher titre in the CNS of infected animals than A7. Neuronal destruction and leucocytic infiltration occurred throughout the forebrain of SFV4-infected rats. A7-infected rats remained clinically normal although degenerate neurons and inflammatory changes were present primarily in the olfactory system. Following infection with either A7-SFV or SFV4, TUNEL-positive nuclei were seen in areas of leucocytic infiltration and among the poorly differentiated cells of the rostral migratory stream. Migrating cells had condensed nuclear chromatin, compacted cytoplasm and intact cellular membranes, characteristic of apoptosis, and were sparsely immunolabelled for viral antigen. In SFV4-infected rats, large numbers of contiguous neurones in forebrain areas exhibited cytoplasmic eosinophilia and karyolysis and were surrounded by phagocytic cells. Such neurones contained dense intracytoplasmic deposits of viral antigen and showed weak cytoplasmic TUNEL staining; electron microscopy showed membrane disruption, organelle disintegration, irregular chromatin condensation and cytoplasmic aggregation of virus particles. Bcl-2 staining was similar in infected and control rats and was most intense in randomly distributed Purkinje cells in the cerebellum; neurons in the olfactory bulbs were unstained. These findings indicate that during SFV encephalitis, infiltrating leucocytes and neural precursor cells undergo apoptosis whilst productively infected neurons undergo necrosis.

Alphavirus Infections↗

PubMed2002

Radical curative efficacy of five-day regimen of primaquine for treatment of Plasmodium vivax malaria in India.

For over 4 decades the antimalarial program in India has been prescribing a 5-day primaquine regimen as an antirelapse therapy to treat Plasmodium vivax malaria. In view of conflicting reports on the effectiveness of this regimen in the Indian subcontinent, and the varying prevalence of P. vivax in various ecosystems in India, the antirelapse efficacy of this regimen was evaluated in Orissa, a malaria endemic state in eastern India where P. falciparum predominates. In 723 cases of P. vivax infection treated with chloroquine alone and followed up weekly for 1 yr, the prevalence of recurrence of parasitaemia with fever was 8.6%. Among another 759 P. vivax cases treated with chloroquine and a 5-day regimen of primaquine at 15 mg/day (adult dose), the recurrence of infection was 6.5%. The difference in recurrence was not significant (P = 0.53). It is important to note that in a great majority of cases of P. vivax in this area, infection did not recur even without treatment with primaquine. This finding, that the use of the 5-day primaquine regimen with chloroquine had no significant advantage over the use of chloroquine alone, undermines the rationale of using primaquine as an antirelapse drug in forested areas with a high prevalence of P. falciparum.

Adolescent↗

PubMed2005

Decision forest analysis of 61 single nucleotide polymorphisms in a case-control study of esophageal cancer; a novel method.

BACKGROUND: Systematic evaluation and study of single nucleotide polymorphisms (SNPs) made possible by high throughput genotyping technologies and bioinformatics promises to provide breakthroughs in the understanding of complex diseases. Understanding how the millions of SNPs in the human genome are involved in conferring susceptibility or resistance to disease, or in rendering a drug efficacious or toxic in the individual is a major goal of the relatively new fields of pharmacogenomics. Esophageal squamous cell carcinoma is a high-mortality cancer with complex etiology and progression involving both genetic and environmental factors. We examined the association between esophageal cancer risk and patterns of 61 SNPs in a case-control study for a population from Shanxi Province in North Central China that has among the highest rates of esophageal squamous cell carcinoma in the world. METHODS: High-throughput Masscode mass spectrometry genotyping was done on genomic DNA from 574 individuals (394 cases and 180 age-frequency matched controls). SNPs were chosen from among genes involving DNA repair enzymes, and Phase I and Phase II enzymes. We developed a novel adaptation of the Decision Forest pattern recognition method named Decision Forest for SNPs (DF-SNPs). The method was designated to analyze the SNP data. RESULTS: The classifier in separating the cases from the controls developed with DF-SNPs gave concordance, sensitivity and specificity, of 94.7%, 99.0% and 85.1%, respectively; suggesting its usefulness for hypothesizing what SNPs or combinations of SNPs could be involved in susceptibility to esophageal cancer. Importantly, the DF-SNPs algorithm incorporated a randomization test for assessing the relevance (or importance) of individual SNPs, SNP types (Homozygous common, heterozygous and homozygous variant) and patterns of SNP types (SNP patterns) that differentiate cases from controls. For example, we found that the different genotypes of SNP GADD45B E1122 are all associated with cancer risk. CONCLUSION: The DF-SNPs method can be used to differentiate esophageal squamous cell carcinoma cases from controls based on individual SNPs, SNP types and SNP patterns. The method could be useful to identify potential biomarkers from the SNP data and complement existing methods for genotype analyses.

Algorithms↗

PubMed1986

Acute febrile cerebrovasculitis: a syndrome of unknown, perhaps rickettsial, cause.

In late 1983, five patients living near Charlottesville, Virginia, were treated for an unusual syndrome of fever, headache, altered mentation, multifocal neurologic signs, and cerebrospinal fluid pleocytosis. Clinical signs of brainstem disease developed in four patients. All five had had recent exposure to forests or wood and contact with flea-infested dogs. Two patients died; one survivor has had recurrent seizures. Brain biopsy samples in two patients and autopsy findings in another showed cerebral vasculitis and perivasculitis involving mostly venules and capillaries. In the autopsy, the severest vascular lesions involved the brainstem and thalami, where they were accompanied by acute fibrinoid necrosis, but discrete vascular lesions of lesser intensity were randomly distributed in the white matter and cortex. Serologic studies on paired specimens in four patients showed significant cross-reacting antibody responses to rickettsial (typhus-group) antigens in the indirect hemagglutination, latex agglutination, and IgM microimmunofluorescence tests, but no agent was visualized or isolated. The cause of this serious inflammatory disorder is unknown.

Acute Disease↗

PubMed1994

[Lansoprazole versus ranitidine in the prevention of early recurrences of digestive hemorrhages from gastroduodenal ulcers. Randomized double-blind multicenter study].

Strong inhibition of acid secretion could be able to decrease gastric and duodenal ulcer early rebleeding. OBJECTIVE--The aim of this double blind randomized trial was to compare early rebleeding rates of 2 groups of patients treated with ranitidine (600 mg/day) or lansoprazole (60 mg/day) per os for 6 consecutive days. METHODS--Seventy five patients with a high risk of rebleeding (clinical and endoscopical criteria) were included in this trial. These ulcers were Ia (n = 10), Ib (n = 20), IIa (n = 13), IIb (n = 32) in Forrest classification. RESULTS--Nineteen out of 75 patients rebled (25.3%): 11 out of 37 (30%) and 8 out of 38 (21%) in the ranitidine and lansoprazole groups respectively. Rates of rebleeding were 10%, 12.5%, 36% and 29% respectively in the ulcers grade Ia (previously treated with endoscopic sclerosis), Ib, IIa and IIb in the Forest classification. CONCLUSION--The rates of rebleeding were not statistically different in the 2 groups of treatment. The high rebleeding rates observed with Forrest IIa and IIb and duodenal ulcers support the need of haemostatic endoscopic therapy associated to antisecretory treatment in such patients.

2-Pyridinylmethylsulfinylbenzimidazoles↗

PubMed2001

Estrogen/progesterone replacement versus pravastatin and their sequential association in hypercholesterolemic postmenopausal women.

OBJECTIVES: The objectives of this study were to assess serum lipid changes in response to an oral estrogen combined with progesterone (Group A) as compared with pravastatin (Group B) and to evaluate the additive effects of the sequential addition of statin to hormonal replacement therapy (HRT) and of HRT to statin. METHODS: Thirty-seven of 63 hypercholesterolemic menopausal women initially submitted to a 4-month diet were randomised to oral conjugated estrogens (0.625 mg)/micronised progesterone (200 mg) or to pravastatin (40 mg). After 6 months, each group received both medications for another 6 months. RESULTS: Nineteen percent of women corrected their lipids below decision levels with diet alone. Low density lipoprotein-cholesterol (LDL-C) decreased by 8+/-5% with HRT and by 26+/-3% (P<0.001) with the statin. These single medications increased high density lipoprotein-cholesterol (HDL-C) by 13+/-5% (P<0.01) and 11+/-7%, respectively. Combined interventions produced cumulative LDL-C reductions of 40+/-2 and 42+/-3% (P<0.001) and additive HDL-C augmentations of 16+/-4 and 23+/-5% (P<0.01) with proportional changes in apolipoprotein (Apo)B-100 and ApoA-1. These combined effects brought the atherogenic index (C/HDL-C) for Groups A and B, respectively, from a moderate (5.18+/-0.25 and 5.87+/-0.18) to a reduced (3.35+/-0.20 and 3.52+/-0.19) risk category. Triglycerides (TG) which were increased by HRT and decreased by the statin returned to baseline during combined treatments. No changes in diet, physical activity or anthropomorphometric measurements explained the lipid modifications. CONCLUSIONS: In menopausal patients with elevated C not responding to diet, pravastatin was most effective to decrease LDL-C, and oral estrogen-micronised progesterone most effective to increase HDL-C. Marked reduction of the atherogenic index is achieved by sequential combinations of medications resulting from beneficial cumulative effects on both C-LDL and C-HDL.

Administration, Oral↗

PubMed2004

Microhabitat associations and seedling bank dynamics in a neotropical forest.

We conducted a rigorous test of tropical tree seedling microhabitat differentiation by examining microhabitat associations, survival and growth of established seedlings of ten tropical tree species representing a four-factor gradient in seed size. Eight microhabitat variables describing soil and light conditions were measured directly adjacent to each of 588 seedlings within twelve 10x100 m belt transects at Paracou, French Guiana, and at 264 reference points along the transects. From these measurements, we defined three principal components describing soil richness, soil softness and canopy openness. Six of ten species (in 9 of 30 total cases) were distributed non-randomly with respect to microhabitat along at least one principal component. However, few species demonstrated clear microhabitat specialization. All shifts in distribution relative to reference points were in the same direction (richer, softer soil). Furthermore, of 135 pairwise comparisons among the species, only 7 were significantly different. More than three-fourths of all seedlings (75.3%) survived over the 2-year monitoring period, but survival rates varied widely among species. In no case was the probability of survival influenced by any microhabitat parameter. Relative height growth rates for the seedlings over 2 years varied from -0.031 cm cm(-1) year(-1) (Dicorynia guianensis, Caesalpiniaceae) to 0.088 cm cm(-1) year(-1) (Virola michelii, Myristicaceae). In only 4 of 30 cases was height growth significantly associated with one of the three principal components. Because the conditions in this study were designed to maximize the chance of finding microhabitat differentiation among a group of species differing greatly in life history traits, the lack of microhabitat specialization it uncovered suggests that microhabitat partitioning among tropical tree species at the established seedling stage is unlikely to contribute greatly to coexistence among these species.

Ecosystem↗

PubMed2006

Biogeography of Brazilian populations of Panstrongylus megistus (Hemiptera, Reduviidae, Triatominae) based on molecular marker and paleo-vegetational data.

In epidemiological terms, Panstrongylus megistus is one of the most important species of triatomine bug in Brazil. Samples from 11 localities were studied using the random amplification of polymorphic DNA (RAPD) technique, which was able to differentiate the study populations clearly. Biogeographical data indicate that these populations could already have arisen 18,000 years ago (C(14)), it being possible to differentiate insects from the Brazilian states of Santa Catarina (SC) in the south, Ceará (CE) in the northeast and another large intermediate block containing the remaining eight populations from five other states. These results agree with those obtained by phenograms constructed from RAPD data, in which the SC population lies opposite those of CE, consistent with the greatest geographical distance between these localities. The other eight populations (Alagoas (AL), Bahia (BA), Goiás (GO), Minas Gerais (MG) and São Paulo (SP)) are closer genetically and originated in areas whose vegetational characteristics have remained similar to each other during the last 18,000 years, thus allowing greater contact between them. The greatest divergence of this group of insects and those of Ceará appears to have occurred 8000 years ago. This more humid period gave rise to other landscape changes, allowing greater differentiation of the vegetation and consequent expansion of P. megistus populations. Formation of the Serras do Mar and Mantiqueira probably created geographical barriers that favored a certain degree of isolation and greater differentiation of the SC population. Atlantic forest remnants within the caatinga domain (created between 25 and 17,000 years ago), where the CE populations originated probably constitute ecological refugia produced by successive amplification and retraction of the most suitable habitats for this species.

Animals↗

PubMed2006

Relationship of vitamin E metabolism and oxidation in exercising human subjects.

During endurance exercise, oxygen consumption by the skeletal muscle can increase 100-200 times. We previously found that during an ultramarathon race (50 km, forest trail through hilly terrain) compared with a day of rest, vitamin E disappeared faster (as measured using 2H-labelled alpha-tocopherol) and lipid peroxidation increased. Therefore, we hypothesized that prior supplementation with antioxidants (vitamins E and C) would decrease oxidative stress during distance running and, therefore, decrease lipid peroxidation and inflammation, decrease DNA damage, decrease muscle damage and/or improve recovery. To test these hypotheses, we carried out a randomized, double-blind study in runners (n 11 females, 11 males) who were participants in an annual ultramarathon race. We found that supplementation with both vitamins E and C only prevented increases in lipid peroxidation, but had no apparent effect on DNA damage, inflammation or muscle damage. These results suggest that the mechanism of oxidative damage is operating independently of the inflammatory and muscle damage responses.

Ascorbic Acid↗

PubMed2004

Variation in mitochondrial DNA reveals multiple distant glacial refugia in black spruce (Picea mariana), a transcontinental North American conifer.

Range-wide genetic variation of black spruce (Picea mariana) was studied using polymerase chain reaction-random fragment length polymorphism markers of the mitochondrial genome. Four polymorphic mitochondrial DNA (mtDNA) loci were surveyed and two or three alleles were detected at each locus, resulting in 10 multilocus mtDNA types or mitotypes. A significant subdivision of population genetic diversity was detected (GST = 0.671; NST = 0.726), suggesting low levels of gene flow among populations. The distribution of mitotypes was not random (NST > GST; P < 0.05) and revealed four partially overlapping zones, presumably representative of different glacial populations. Comparison of the genetic structure derived from mtDNA markers and the colonization paths previously deduced from the fossil and pollen records allow us to infer at least three southern and one northeastern glacial populations for black spruce. The patterns revealed in this study suggest that black spruce shares its biogeographical history with other forest-associated North American species.

Canada↗

PubMed1999

[Ticks Ixodes ricinus (Linnaeus, 1758) from selected municipal forests of the city Poznań and their infection with the spirochetes Borrelia burgdorferi senso lato].

The results of research (1997-1998) on the occurrence of the spirochetes Borrelia burgdorferi s.l. in ticks Ixodes ricinus (L.) in selected municipal forests of the city of Poznań (localities--districts of Poznań: 1 Debiec, 2 Marcelin, 3 Golecin and Wola, 4 Krzyzowniki and Smochowice, 5 Kiekrz and Strzeszynek, 6 Morasko, 7 Piatkowo, 8 Umultowo, 9 Naramowice and Rózany Młyn, 10 Malta and Antoninek) are presented. A total of 1432 ticks were collected from 10 localities (748 larvae, 590 nymphs, 47 males, and 47 females). Out of this number, 266 specimens were selected at random for further analysis (20 larvae, 160 nymphs, 44 males, and 42 females) which were then tested for the presence of the spirochetes using the PCR technique (tab. I-III, fig. 1). Spirochetes were found in 60 specimens (22.6%). Percentages of infected nymphs and males were similar: 25.6% and 27.3%, respectively. The level of infection of females was lower (14.3%) and of larvae lowest (5.0%). Infected ticks were found in all ten localities, but their proportions differed from site to site and varied from 9.5% (Piatkowo) to 34.6% (Krzyzowniki and Smochowice). Special attention was devoted to those municipal woods where ticks were abundant (Kiekrz and Strzeszynek, as well as Malta and Antoninek, and relatively numerous Debiec) and where their extensiveness of infestation was high (Krzyzowniki and Smochowice: 34.6%; Debiec: 29.6%; Naramowice and Rózany Młyn: 28.6%; Malta and Antoninek: 28.1%; and Golecin and Wola: 26.9%). After summing up all the data from the literature on Wielkopolska and the city of Poznań, the mean extensiveness of infestation in Wielkopolska turns out to be 21.8% and in Poznań slightly higher, 22.2% (tab. IV). The infection levels of the particular developmental stages are different, though: highly variable in nymphs (8.3-25.6%), and more stable in males (22.0-27.3%) and females (22.0-24.5%).

Animals↗

PubMed2002

Radiation-use efficiency of a forest exposed to elevated concentrations of atmospheric carbon dioxide.

We compared radiation-use efficiency of growth (epsilon;), defined as rate of biomass accumulation per unit of absorbed photosynthetically active radiation, of forest plots exposed to ambient (approximately 360 micro l l-1) or elevated (approximately 560 micro l l-1) atmospheric CO2 concentration ([CO2]). Large plots (30-m diameter) in a loblolly pine (Pinus taeda L.) plantation, which contained several hardwood species in the understory, were fumigated with a free-air CO2 enrichment system. Biomass accumulation of the dominant loblolly pines was calculated from monthly measurements of tree growth and site-specific allometric equations. Depending on the species, leaf area index (L*) was estimated by three methods: optical, allometric and litterfall. Based on the relationship between tree height and diameter during the first 3 years of exposure, we conclude that elevated [CO2] did not alter the pattern of aboveground biomass allocation in loblolly pine. There was considerable variation in L* estimates by the different methods; total L* was 18-42% lower when estimated by the optical method compared with estimates from allometric calculations, and this discrepancy was reduced when optical measurements were corrected for the non-random distribution of loblolly pine foliage. The allometric + litterfall approach revealed a seasonal maximum total L* of 6.2-7.1 with about 1/3 of the total from hardwood foliage. Elevated [CO2] had only a slight effect on L* in the first 3 years of this study. Mean epsilon; (+/- SD), calculated for loblolly pine only, was 0.49 +/- 0.05 and 0.62 +/- 0.04 g MJ-1 for trees in the ambient and elevated [CO2] plots, respectively. The 27% increase in epsilon; in response to CO2 enrichment was caused primarily by the stimulation of biomass increment, as there was only a small effect of elevated [CO2] on L* during the initial years of fumigation. Long-term increases in atmospheric [CO2] can increase epsilon; in closed-canopy forests but the absolute magnitude and duration of this increase remain uncertain.

Biomass↗

PubMed2000

Metabolism and temperature regulation during daily torpor in the smallest primate, the pygmy mouse lemur (Microcebus myoxinus) in Madagascar.

Thermoregulation, energetics and patterns of torpor in the pygmy mouse lemur, Microcebus myoxinus, were investigated under natural conditions of photoperiod and temperature in the Kirindy/CFPF Forest in western Madagascar. M. myoxinus entered torpor spontaneously during the cool dry season. Torpor only occurred on a daily basis and torpor bout duration was on average 9.6 h, and ranged from 4.6 h to 19.2 h. Metabolic rates during torpor were reduced to about 86% of the normothermic value. Minimum body temperature during daily torpor was 6.8 degrees C at an ambient temperature of 6.3 degrees C. Entry into torpor occurred randomly between 2000 and 0620 hours, whereas arousals from torpor were clustered around 1300 hours within a narrow time window of less than 4 h. Arousal from torpor was a two-step process with a first passive climb of body temperature to a mean of 27 degrees C, carried by the daily increase of ambient temperature when oxygen consumption remained more or less constant, followed by a second active increase of oxygen consumption to further raise the body temperature to normothermic values. In conclusion, daily body temperature rhythms in M. myoxinus further reduce the energetic costs of daily torpor seen in other species: they extend to unusually low body temperatures and consequently low metabolic rates in torpor, and they employ passive warming to reduce the energetic costs of arousal. Thus, these energy-conserving adaptations may represent an important energetic aid to the pygmy mouse lemur and help to promote their individual fitness.

Animals↗

PubMed1990

Identification of different agrobacterium strains isolated from the same forest nursery.

Several Agrobacterium strains isolated from the same forest nursery from 1982 to 1988 were compared by serological, biochemical, and DNA-DNA hybridization methods. Similarities among strains belonging to biovar 2 were observed by indirect immunofluorescence, whereas biovar 1 strains showed serological heterogeneity. Electrophoretic analysis of bacterial envelope-associated proteins showed that few bands appeared in the strains belonging to biovar 1, whereas many proteins appeared in the case of biovar 2 strains. Chromosomal DNA was analyzed with six random C58 chromosomal fragments. None of the six probes hybridized to the DNA of the two biovar 2 strains. One of the probes gave the same hybridization pattern with all biovar 1 strains, whereas the other probes yielded different patterns. The vir regions were closely related in the different pathogenic strains. The T-DNA and replication regions were less conserved and showed some variations among the strains.

Journal Article↗

PubMed2002

Degree of threat to the biological diversity in the Ilha Grande State Park (RJ) and guidelines for conservation.

The State Park of Ilha Grande is only a part (5,594 hectares) of the entire island (19,300 hectares) which is located off the south coast of Rio de Janeiro state, between the cities of Mangaratiba and Angra dos Reis. Approximately half of the Park area (47%) is covered by dense Atlantic forest. The secondary forest growth is in a process of ecological succession close to attaining maturity (43%) and the remaining part (10%) is composed of human-altered areas (1%), rocky outcrops with herbaceous vegetation (7%), mangroves and beaches (2%). The fauna is well represented but already shows signs of degradation with introduced species. The analysis of the degree of threat has shown that the dense forest habitat has a relatively stable status of conservation while the secondary forest, the mangrove and the herbaceous vegetation on rocky outcrops (and their fauna) are categorized as vulnerable. The area altered by human occupation is considered threatened. Since the coastal area where Ilha Grande is located is well known for its beautiful scenery (known as the green coast, because of the contrast between the ocean and the Atlantic forest covering the Serra do Mar mountain chain). There is a strong possibility for tourism to become the means in which to achieve economic sustainability for conservation. Contradictorily, tourism is also the major threat to local biodiversity and its landscape units. Because tourism is not organized and controlled, during high season the numbers grow above local capacity, giving rise to a proliferation of hotels, guesthouses and camping grounds. The resulting untreated open sewage, random garbage disposal and other harmful activities form the major threats to biodiversity.

Animals↗

PubMed2006

Composition, diversity, and spatial relationships of anurans following wetland restoration in a managed tropical forest.

We investigated the composition, diversity, and patterns of spatial use of an anuran community following a wetland restoration project in a managed tropical monsoon forest in southern Taiwan. Anurans comprising eight species in seven genera and four families reached a mean density of 0.025+/-0.004 anurans m(-2) within a year. The three most important species in terms of frequency of occurrence and relative abundance all had an early appearance; only the most abundant Fejervarya limnocharis (62.2% of total accounts), however, remained present throughout the entire year. The distribution of anurans observed among habitat zones was non-random, with most records occurring in densely planted (42.8%) and running-water (23.9%) zones, and the fewest in a buffer zone adjacent to a paved road. Mean numbers of anurans were correlated with the mean percent vegetation cover among individually divided small pools. Microhyla ornate, M. heymonsi, Polypedates megacephalus, and F. limnocharis appeared to be more heterogeneous in their use of space than Buergeria japonicus. Species differed in their most frequently used habitat zones within the wetland site, with the pairs F. limnocharis and P. megacephalus, and M. ornate and Bufo melanostictus, exhibiting similar respective distributions among zones. Our study demonstrates the value of even a small, isolated wetland in contributing to and maintaining regional amphibian diversity. Patterns of spatial relationships of this anuran community have important implications for the conservation of local populations across species.

Animals↗

PubMed2001

Mapping distributions of chromosomal forms of Anopheles gambiae in West Africa using climate data.

The mosquito Anopheles gambiae Giles sensu stricto (Diptera: Culicidae), the principal vector of malaria in West Africa, comprises several chromosomal forms (e.g. Bissau, Forest, Mopti, Savanna) associated with climatic zones. Here we show how climate data can be used to map the geographical distribution of these chromosomal forms. The climate at 144 sites surveyed for mosquitoes in West Africa between 1971 and 92 was determined using computerized climate surfaces. Forest and Bissau forms occurred at relatively wet sites: median annual precipitation 1325 mm and 1438 mm, respectively, interquartile ranges (IQR) 1144-1858 mm and 1052-1825 mm), whilst the Mopti form was found at dry sites (annual 938 mm, IQR 713-1047 mm) and the Savanna form at sites intermediate between the wet and dry forms (annual 1067 mm, IQR 916-1279). Logistic regression analyses of the climate variables were carried out on a stratified random sample of half the sites. The resulting models correctly classified over 80% of the sites for presence or absence of each chromosomal form. When these models were tested against excluded sites they were also correct at over 80% of sites. The combined data produced models that were correct at over 86% of sites. Mean annual precipitation, evapotranspiration, minimum temperature and maximum temperature were the most important climate variables correlated with the distribution of these forms of An. gambiae. We used the logistic models to map the distribution of each chromosomal form within the reported range for An. gambiae s.s. in West Africa employing a geographical information system. Our maps indicate that each chromosomal form favours particular climate envelopes in well-defined ecoclimatic zones, although these forms are sympatric at the edges of their ranges. This study demonstrates that climate can be used to map the distribution of chromosomal forms of insects across large areas.

Africa, Western↗

PubMed2006

Comparing the use of indigenous knowledge with classification and ordination techniques for assessing the species composition and structure of vegetation in a tropical forest.

Identification of groups that are similar in their floristic composition and structure (habitat types) is essential for conservation and forest managers to allocate high priority areas and to designate areas for reserves, refuges, and other protected areas. In this study, the use of indigenous knowledge for the identification of habitat types in the field was compared against an ecological characterization of habitat types, including their species composition obtained by using classification and ordination techniques for a tropical landscape mosaic in a rural Mayan area of Quintana Roo, Mexico. Plant diversity data calculated from 141 sampled sites chosen randomly on a vegetation class's thematic map obtained by multispectral satellite image classification were used for this propose. Results indicated high similarity in the categorization of vegetation types between the Mayan classification and those obtained by cluster and detrended correspondence analysis. This suggests that indigenous knowledge has a practical use and can be comparable to that obtained by using science-based methods. Finally, identification and mapping of vegetation classes (habitat types) using satellite image classification allowed us to discriminate significantly different species compositions, in such a way that they can provide a useful mechanism for interpolating diversity values over the entire landscape.

Biodiversity↗