Reconstructing historical forest cover change in the Lower Amazon floodplains using the LandTrendr algorithm

ABSTRACTThe Amazon várzeas are an important component of the Amazon biome, but anthropic and climatic impacts have been leading to forest loss and interruption of essential ecosystem functions and services. The objectives of this study were to evaluate the capability of the Landsat-based Detection of Trends in Disturbance and Recovery (LandTrendr) algorithm to characterize changes in várzeaforest cover in the Lower Amazon, and to analyze the potential of spectral and temporal attributes to classify forest loss as either natural or anthropogenic. We used a time series of 37 Landsat TM and ETM+ images acquired between 1984 and 2009. We used the LandTrendr algorithm to detect forest cover change and the attributes of "start year", "magnitude", and "duration" of the changes, as well as "NDVI at the end of series". Detection was restricted to areas identified as having forest cover at the start and/or end of the time series. We used the Support Vector Machine (SVM) algorithm to classify the extracted attributes, differentiating between anthropogenic and natural forest loss. Detection reliability was consistently high for change events along the Amazon River channel, but variable for changes within the floodplain. Spectral-temporal trajectories faithfully represented the nature of changes in floodplain forest cover, corroborating field observations. We estimated anthropogenic forest losses to be larger (1.071 ha) than natural losses (884 ha), with a global classification accuracy of 94%. We conclude that the LandTrendr algorithm is a reliable tool for studies of forest dynamics throughout the floodplain.

Evolution of Cardiovascular Diseases Mortality in the Counties of the State of Rio de Janeiro from 1979 to 2010

Background: Cardiovascular Diseases (CVD) are the leading cause of death in Brazil. Objective: To estimate total CVD, cerebrovascular disease (CBVD), and ischemic heart disease (IHD) mortality rates in adults in the counties of the state of Rio de Janeiro (SRJ), from 1979 to 2010. Methods: The counties of the SRJ were analysed according to their denominations stablished by the geopolitical structure of 1950, Each new county that have since been created, splitting from their original county, was grouped according to their former origin. Population Data were obtained from the Brazilian Institute of Geography and Statistics (IBGE), and data on deaths were obtained from DataSus/MS. Mean CVD, CBVD, and IHD mortality rates were estimated, compensated for deaths from ill-defined causes, and adjusted for age and sex using the direct method for three periods: 1979–1989, 1990–1999, and 2000–2010, Such results were spatially represented in maps. Tables were also constructed showing the mortality rates for each disease and year period. Results: There was a significant reduction in mortality rates across the three disease groups over the the three defined periods in all the county clusters analysed, Despite an initial mortality rate variation among the counties, it was observed a homogenization of such rates at the final period (2000–2010). The drop in CBVD mortality was greater than that in IHD mortality. Conclusion: Mortality due to CVD has steadily decreased in the SRJ in the last three decades. This reduction cannot be explained by greater access to high technology procedures or better control of cardiovascular risk factors as these facts have not occurred or happened in low proportion of cases with the exception of smoking which has decreased significantly. Therefore, it is necessary to seek explanations for this decrease, which may be related to improvements in the socioeconomic conditions of the population.

Diversity and structure of microcrustacean assemblages (Cladocera and Copepoda) and limnological variability in perennial and intermittent pools in a semi-arid region, Bahia, Brazil

Temporary wetlands undergo recurrent drought due to the scarcity of water, which disrupts the hydrological connectivity with adjacent aquatic systems. However, some environments retain water for longer periods, allowing greater persistence of the community. The current study evaluated differences in the microcrustacean assemblages and limnological variability between perennial and intermittent pools in a semi-arid region of Brazil. The abiotic features (water temperature, pH, total alkalinity, electrical conductivity and depth) of intermittent pools were affected more than perennial pools due to loss of water volume. This may have contributed to a higher average richness and diversity index in some intermittent pools and differences in the structure of the assemblages. The lowest species richness and diversity were recorded where physical factors, such as a large quantity of suspended solids and variability in the electrical conductivity of the water and pH, make the environment unsuitable for these organisms. These results suggest that community development in intermittent pools is interrupted by the dry season; when the water returns, due to rainfall or rising groundwater, each pond undergoes a different process of colonization. In these circumstances, the biological importance of temporary aquatic environments is clear, since such pools provide shelters and have an important role in the maintenance of the regional diversity of aquatic environments.

Reproductive strategy of a non-annual rivulid in a perennial wetland

ABSTRACT Atlantirivulus riograndensis (Costa & Lanés, 2009) is a fish registered to the basin of Patos lagoon and the adjacent coastal plains in southern states of Rio Grande do Sul and Santa Catarina, Brazil, found in shallow water courses with that have large quantities of aquatic vegetation and forest edges. The objective of this study was to investigate the reproductive strategy and tactics of this species including the sex ratio, the length at first maturity, spawning type, fecundity and the possible associations among reproduction and abiotic factors. Sampling of specimens occurred in perennial wetlands within the Banhado dos Pachecos wildlife refuge, in the city of Viamão, state of Rio Grande do Sul, Brazil, which is a conservation unit that belongs to an area of environmental protection in the Pampa Biome. The capture of 30 A. riograndensis specimens per month occurred from January to December of 2012. A total of 188 females and 172 males were captured and the total sex ratio was 1:1 in the sampled population. Sexual maturity of the species occurs after 13.59 and 11.92 mm (SL) for females and males, respectively. Both a multiple spawning and a long reproductive period (since August to March) were confirmed by the presence of post-ovulatory follicles that were observed through histological analysis and the values of the gonadosomatic index in females considered spawning capable. The average absolute fecundity of the species is of 19.33 (± 6.18) vitellogenic oocytes in mature ovaries. No significant relationship was found between mean GSI and the abiotic data. Reproductive tactics presented by A. riograndensis indicate a species with an opportunistic reproductive strategy, following the pattern of other species of the Rivulidae family.

Sobre a dosagem fluorométrica da riboflavina na urina

Urinary determinations of riboflavine were done with the methods of Emmerie, Ferrebee and Najjar. Recovery experiments gave better results with the method of Ferrebee and the modification of Najjar. Some details are presented and calibration curves are constructed for the use of the Pulfrich fotometer and the pfalz and Bauer fluorphotometer. In two normal cases it was observed that the excretion of riboflavine is great after 2 to 5hs of the injection of 1mg. of synthetic riboflavine. Normal cases excreted in an adequate diet 12 to 145 microg. of riboflavine per 100cc. of urine and 76 to 1300 microg. per day.

Esquistossomose mansônica: dinâmica da transmissão

The following remarks were addressed at the round table that discussed the alternative approaches to schistosomiasis control. The address begins with a short analysis of the progressive spread of the area of distribution of the disease, and of the difficulties faced by those in charge of control programs, conventional or otherwise. A model was sketched, taking into consideration the distinct classes of factors involved in the dynamics of transmission: biological, immunological, ecological, socio-cultural, and economical. The true significance and pertinence of such a model was analysed, and the relevant questions that must be answered before a true representative model can be constructed, were listed.

Development of nuclear DNA probes for the typing of Trypanososma cruzi

We have developed and tested a new way of typing Trypanosoma cruzi, mamely the use of cloned nuclear DNA fragments as genetic markers. Restriction fragment length polymorphisms were verified on Soutern blots hybridized to random probes. Fragment patterns were analyzed and dendrograms constructed. Our results on well characterized laboratory strains correlate well to published isoenzyme studies. Some of the probes were also hybridized to chromosomes separated by pulse field gel electrophoresis a higher degree of heterogeneity was observed at this level.

Detection of Babesia bigemina infection: use of a DNA probe - a review

The development of a repetitive DNA probe for Babesia bigemina was reviewed. The original plasmid (p(Bbi)16) contained an insert of B. bigemina DNA of approximately 6.3 kb. This probe has been evaluated for specificityand analytical sensitivity by dot hybridization with isolates from Mexico, the Caribbean region and Kenya. A partial restriction map has been constructed and insert fragments have been subcloned and utilized as specific DNA probes. A comparison of 32P labelled and non-radioactive DNA probes was presented. Non-radioctive detection systems that have been used include digoxigenin dUTP incorporation, and detection by colorimetric substrate methods. Derivatives from the original DNA probe have been utilized to detect B. bigemina infection in a) experimentally inoculated cattle, b) field exposed cattle, c) infected Boophilus microplus ticks, and d) the development of a PCR amplification system.

The p53 gene expression and its developmental regulation in schistosomes

We have studied the gene expression, especially of the oncoproteins, and its regulation in schistosomes. Schistosomes have a complex life cycle with defined dimorphic lifestyle. The parasite are so far unique in biology in expressing oncogene products in their adult stage. In order to characterize the expression and developmental regulation, a lambda gt 11 cDNA library and lambda EMBL4 genomic DNA library of each growth stage of Schistosoma mansoni and S. japonicum was constructed, and was screened with various monoclonal antibodies against ongogene products. One positive plaque reacted to anti-p53 antibody (Ab-2, Oncogene Science, Inc.) was further analyzed. This fusion protein was about 120 KDa in molecular weights, and expressed as 1.4 Kb RNA in the adult stage. P53 gene is well-known as the negative regulator of the cell cicle, and the mutations in the gene are turning out to be the most common genetic alterations in human cancers. The comparison of the gene structure among species and stages were being conducted. Chromosome structures, C-band formation, and the results of in situ hybridization using the phage probe would be discussed.

An oligonucleotide probe derived from kDNA minirepeats is specific for Leishmania (Viannia)

Sequence analysis of Leishmania (Viannia) kDNA minicircles and analysis of multiple sequence alignments of the conserved region (minirepeats) of five distinct minicircles from L. (V.) braziliensis species with corresponding sequences derived from other dermotropic leishmanias indicated the presence of a sub-genus specific sequence. An oligonucleotide bearing this sequence was designed and used as a molecular probe, being able to recognize solely the sub-genus Viannia species in hybridization experiments. A dendrogram reflecting the homologies among the minirepeat sequences was constructed. Sequence clustering was obtained corresponding to the traditional classification based on similarity of biochemical, biological and parasitological characteristics of these Leishmania species, distinguishing the Old World dermotropic leishmanias, the New World dermotropic leishmanias of the sub-genus Leishmania and of the sub-genus Viannia.

Forest culicinae mosquitoes in the environs of samuel hydroeletric plant, state of Rondônia, Brazil

Data on frequency and seasonal distribution of culicinae were recorded in the forest near a recently constructed hydroelectric plant - Samuel, in the State of Rondônia, Brazilian Amazon. Collections were performed almost daily from August 1990 to July 1991, between 6 and 9 p.m., using human bait. A total of 3,769 mosquitoes was collected, representing 21 species, including seven new records for the State of Rondônia. The most frequently collected species were Aedes fulvus (25%) and Ae. pennai (12.3%). The highest density for the majority of mosquito species coincided with the rainy season.

Contrasting Genomic Variability between Clones from Field Isolates and Laboratory Populations of Schistosoma mansoni

The extent of genomic variability of clones of Schistosoma mansoni obtained from field isolates was compared with that of strains that have been laboratory maintained. Analysis was undertaken using randomly amplified polymorphic dNAs (RAPDs) generated with three primers. Phenograms showing the similarity among the clones were constructed. The data showed that while the laboratory strain is highly homogeneous the clones derived from the field populations were highly variable with 43% of RAPDs exhibiting polymorphisms among 23 clones. Clones isolated from the same infected individual were always more closely grouped than clones from different individuals. The data clearly demonstrated that earlier analyses of the genomic variability in S. mansoni have underestimated this phenomenon due to the failure to examine field isolates

Towards the Physical Map of the Trypanosoma cruzi Nuclear Genome: Construction of YAC and BAC Libraries of the Reference Clone T. cruzi CL-Brener

Strategies to construct the physical map of the Trypanosoma cruzi nuclear genome have to capitalize on three main advantages of the parasite genome, namely (a) its small size, (b) the fact that all chromosomes can be defined, and many of them can be isolated by pulse field gel electrophoresis, and (c) the fact that simple Southern blots of electrophoretic karyotypes can be used to map sequence tagged sites and expressed sequence tags to chromosomal bands. A major drawback to cope with is the complexity of T. cruzi genetics, that hinders the construction of a comprehensive genetic map. As a first step towards physical mapping, we report the construction and partial characterization of a T. cruzi CL-Brener genomic library in yeast artificial chromosomes (YACs) that consists of 2,770 individual YACs with a mean insert size of 365 kb encompassing around 10 genomic equivalents. Two libraries in bacterial artificial chromosomes (BACs) have been constructed, BACI and BACII. Both libraries represent about three genome equivalents. A third BAC library (BAC III) is being constructed. YACs and BACs are invaluable tools for physical mapping. More generally, they have to be considered as a common resource for research in Chagas disease

Vital Statistics of Panstrongylus geniculatus (Latreille 1811) (Hemiptera: Reduviidae) under Experimental Conditions

A statistical evaluation of the population dynamics of Panstrongylus geniculatus is based on a cohort experiment conducted under controlled laboratory conditions. Animals were fed on hen every 15 days. Egg incubation took 21 days; mean duration of 1st, 2nd, 3rd, 4th, and 5th instar nymphs was 25, 30, 58, 62, and 67 days, respectively; mean nymphal development time was 39 weeks and adult longevity was 72 weeks. Females reproduced during 30 weeks, producing an average of 61.6 eggs for female on its lifetime; the average number of eggs/female/week was 2.1. Total number of eggs produced by the cohort was 1379. Average hatch for the cohort was 88.9%; it was not affected by age of the mother. Age specific survival and reproduction tables were constructed. The following population parameters were evaluated, generation time was 36.1 weeks; net reproduction rate was 89.4; intrinsic rate of natural increase was 0.125; instantaneous birth and death rates were 0.163 and 0.039 respectively; finite rate of increase was 1.13; total reproductive value was 1196 and stable age distribution was 31.2% eggs, 64.7% nymphs and 4.1% adults. Finally the population characteristics of P. geniculatus lead to the conclusion that this species is a K strategist.

Wild birds as hosts of Amblyomma cajennense (Fabricius, 1787) (Acari: Ixodidae)

We evaluated the prevalence, mean intensity and relative density of ticks in 467 wild birds of 67 species (12 families) from forest and cerrado habitats at two protected areas of Minas Gerais, between March and September 1997. Ticks collected (n=177) were identified as larvae and nymphs of Amblyomma cajennense and four other species of Amblyomma. We report for the first time 28 bird species as hosts of the immature stages of A. cajennense, demonstrating the lack of host specificity of the larvae and nymphs. A. cajennense had 15% prevalence on birds, with a mean infestation intensity of 0.37 ticks per host sampled, and 2.5 ticks per infested bird. Prevalence varied in relation to host species, diet and between birds from forests at two successional stages. There were no differences in relation to host forest dependence, participation in mixed flocks of birds, and nest type constructed. A. cajennense is a species of medical and veterinary importance, occurring on domestic animals but is known little of its occurrence on wildlife.