Changes in the relationship between society and nature in the Mezzo-region of Southeastern Pará, Amazon, Brazil

With this work, the authors wish to show some of the alterations in the pattern of relations between society and nature, which have taken place throughout the 20th century in the Parauapebas and Itacaiúnas river valleys, as well as in parts of the Tocantins River valley, in southeastern Pará. This is accomplished through descriptions based on Coudreau's first-hand accounts (1889), transcribed in "Voyage a Itaboca et a L'Itacayuna", published in 1897, which depicts an area almost totally covered by forest. This is followed by a counter view made possible through the LandSat 5 satellite sensors, with images of those valleys in 2001, showing the consequences of society transformations and pressure on natural resources, and above all the dramatic decrease in the size of the forest, reduced to 52 percent of the 63,000 square kilometers analyzed herein.

Optimum dietary protein requirement for Amazonian Tambaqui, Colossoma macropomum Cuvier, 1818, fed fish meal free diets

Fish meal free diets were formulated to contain graded protein levels as 25% (diet 1), 30% (diet 2), 35% (diet 3) and 40% (diet 4). The diets were fed to tambaqui juveniles (Colossoma macropomum) (46.4 ± 6.3g) in randomly designed recirculating systems for 60 days, to determine the optimum protein requirement for the fish. The final weight of the fish, weight gain (28.1, 28.5, 32.2, 28.0g) and specific growth rate increased (P>0.05) consistently with increasing dietary protein up to treatment with 35% protein diet and then showed a declining trend. Feed intake followed the same trend resulting in best feed efficiency (62.5%) in fish fed diet with 35% protein. Similarly, the protein intake increased significantly with increasing dietary protein levels and reduced after the fish fed with 35% protein; while protein efficiency ratio (2.28, 1.99, 1.87, 1.74) decreased with increasing dietary protein levels. Carcass ash and protein had linear relationship with dietary protein levels while the lipid showed a decreasing trend. Ammonia content (0.68, 0.73, 0.81, 1.21 mg L-1) of the experimental waters also increased (P<0.05) with increasing protein levels while pH, dissolved oxygen and temperature remained fairly constant without any clear pattern of inclination. Broken-line estimation of the weight gain indicated 30% protein as the optimum requirement for the fish.

Fine-root production in two secondary forest sites with distinct ages in Eastern Amazon

The objective of this work was to assess the fine-root (≤ 2 mm diameter) production dynamics of two forest regrowths at different ages. Fine-root production was monitored by the ingrowth core method in one 18-year-old site (2 ha) and one 10-year-old site (0.5 ha), both localized in the Apeú region, Northern Pará State, Brazil. The sites were abandoned after successive shifting cultivation, beginning in 1940. Monthly production of live fine-root was similar between sites and was influenced by rainfall seasonality, with higher production during the dry season than the wet season for mass and length. However, mortality in terms of mass was higher in the 10-year-old site than in the 18-year-old site. The seasonality influenced mortality only in the 18-year old site following the pattern observed for live fine-root. The influence seasonal on mortality in terms of length was different between sites, with higher mortality during the wet season in the 10-year-old site and higher mortality during the dry season in the 18-year-old site. Specific root length was higher during the wet season and at the 10-year-old site. Fine-root production was not influenced by the chronosequence of the sites studied, probably fine-root production may have already stabilized in the sites or it depended more on climate and soil conditions. The production of fine-roots mass and length were indicators that generally showed the same pattern.

Cryptic species in Pagamea coriacea sensu lato (Rubiaceae): evidence from morphology, ecology and reproductive behavior in a sympatric context

In this study we explore morphological and ecological variation in sympatric populations of Pagamea coriacea s.l. - a species complex from white-sand vegetation in the Amazon. A total of 147 trees were sampled and monitored at three nearby sites in Central Amazon, Brazil. Multivariate analyses of morphology indicated two distinct groups (A and B), which also differed in bark type, each containing subgroups associated with sexual dimorphism. However, a single hermaphroditic individual was observed within group B. As expected, all pistillate plants produced fruits, but 23% of the staminate plants of group B, and 5% of group A also produced fruits. This variation suggests that the sexual systems of both groups are between dioecy and gynodioecy. There was an overlap in flowering phases between the two groups, but the pattern of floral maturation differed. Ecologically, plants of group B were found in more shaded habitats and over sandstone bedrocks, while group A was prevalent in deeper sandy soils as canopy plants. The significances of morphological and environmental differences were tested by a multivariate analysis of variance, and a canonical discriminant analysis assessed the importance of variables. The coexistence in sympatry of two discrete morphological groups in the P. coriacea s.l., with different habitat preferences and reproductive behaviors, indicates they represent distinct species.

Density-dependent morphological plasticity and trade-offs among vegetative traits in Eichhornia crassipes (Pontederiaceae)

Density-dependent responses are an important component of the organism life-history, and the resource allocation theory is a central concept to the life-history theory. When resource allocation varies due to environmental changes, a plant may change its morphology or physiology to cope with the new conditions, a process known as phenotypic plasticity. Our study aimed to evaluate how plant density affects Eichhornia crassipes allocation patterns. A total of 214 individuals in high and low density were collected. The density effect was observed in all plant traits examined including biomass accumulation. All traits of E. crassipes demonstrated higher values in high density conditions, except for biomass of leaves. Density exhibited a high influence on vegetative traits of E. crassipes, but did not influence allocation pattern, since a trade-off among the vegetative traits was not found. The morphological plasticity and the absence of trade-offs were discussed as strategies to overcome neighbor plants in competition situations. In high density conditions, there were clear changes in the morphology of the plants which probably allows for their survival in a highly competitive environment.

Seasonal and spatial variations in limnological conditions of a floodplain lake (lake Catalão) connected to both the Solimões and Negro Rivers, Central Amazonia

Lakes play an important role in biogeochemical, ecological and hydrological processes in the river-floodplain system. The aim of this study was to evaluate the dynamics of the limnological conditions of Catalão Lake, an Amazon floodplain lake. Thus, some of the main limnological environment variables (O2, temperature, pH, nutrient, electrical conductivity) of the Catalão Lake were analyzed under temporal and spacial scales. The study was conducted between November/2004 and August/2005. Sampling excursion were carried out every three months; one excursion for each of the four different hydrological periods (low water, rising water, high water and falling water). Sampling points were chosen so that it could be obtained a gradient of the distance from Negro River. Limnological profiles in Catalão Lake showed generally acidic to slightly alcaline water, with low levels of dissolved oxygen and low concentrations of soluble reactive phosphorous. The Negro River seems to exert the main influence during the rising water period, while the Solimões River is the principal controlling river during peak water. The Principal Component Analysis (PCA) grouped the seasonal collections by hydrological period, showing the formation of a north-south spatial gradient within the lake in relation to the limnological variables. Multivariate dispersion analysis based on distance-to-centroid method demonstrated an increase in similarity over the course of the hydrological cycle, as the lake was inundated in response to the flood pulse of the main river channels. However, the largest spatial homogeneity in the lake was observed in the epilimnion layer, during the falling water period. The daily analysis of variation indicated an oligomitic pattern during the years in which the lake was permanently connected to the Negro River. Although Catalão Lake receives large quantities of both black water from the Negro River and sediment-filled water from the Solimões River, the physical and chemical characteristics of the lake are more similar to those of the Solimões (várzea lake) than the Negro (blackwater lake).

Nesting and neonates of the yellow-spotted river turtle (Podocnemis unifilis, Podocnemididae) in the Araguari River basin, eastern Amazon, Brazil

Predation and alteration of microhabitats may represent high risk for nesting of Amazonian turtles. This study aimed at investigating the nesting and body parameters of neonates of Podocnemis unifilis in the Araguari River basin, State of Amapá, Brazil. The spawning sites of this turtle were monitored along the Falsino River (a region with two reserves) and in the urban area of the Porto Grande city along the Araguari River, from August to December 2011. A total of 180 nests were found and the nesting occurred from September to November, with prevalence in October. Eggs hatching occurred in December. The mean incubation period was 63.5 ± 5.2 days and the eggs hatching success was 25%. However, approximately 80% of the nests had suffered predation mainly by humans, which occurred in both the protected areas of the reserves and the urban area. The pattern of nesting site choice was discussed. Egg size was larger than that previously described for the same turtle species in the other regions. The body condition index of neonates indicated a good use of vitelline reserves. The results indicate the urgent need for strategic actions to conserve and maintain the natural stocks of this relatively vulnerable turtle in the region.

Reproductive biology of Ameerega trivittata (Anura: Dendrobatidae) in an area of terra firme forest in eastern Amazonia

The reproductive success of tropical amphibians is influenced by factors such as body size and the characteristics of breeding sites. Data on reproductive biology are important for the understanding of population dynamics and the maintenance of species. The objectives of the present study were to examine the abundance of Ameerega trivittata, analyze the use of microhabitats by calling males and the snout-vent length (SVL) of breeding males and females, the number of tadpoles carried by the males and mature oocytes in the females, as well as the relationship between the SVL of the female and both the number and mean size of the mature oocytes found in the ovaries. Three field trips were conducted between January and September, 2009. A total of 31 plots, with a mean area of 2.3 ha, were surveyed, resulting in records of 235 individuals, with a mean density of 3.26 individuals per hectare. Overall, 66.1% of the individuals sighted were located in the leaf litter, while 17.4% were perched on decaying tree trunks on the forest floor, 15.7% on the aerial roots of Cecropia trees, and 0.8% on lianas. Males were observed transporting a mean of 10.8 tadpoles on their backs. A significant correlation was found between the size of the females and the mean diameter of the oocytes. New data were collected on the size of oocytes and no pattern was found in the type of perches used by calling males of the different Ameerega species.

Polychromatism of populations of Corallus hortulanus (Squamata: Boidae) from the southern Amazon Basin, Brazil

The Amazon tree boa Corallus hortulanus is known for featuring a wide variation in color pattern and design markings. Although there are studies on its polychromatism, none of them addresses the geographic variation in the color pattern of this species. The aim of this study was to describe the chromatic variation found in the populations of C. hortulanus from the southern Amazon Basin and its relationship with geographic distribution of the species. Analysis of both design markings and color patterns on 112 C. hortulanus specimens from the southern Amazon Basin interfluves resulted in the identification of six distinct morphotypes. Grayish-brown coloration and elongated diamond-shaped patterns were the most frequent patterns. Two morphotypes showed a tendency of correlation with the geographical distribution of those species found in Madeira and Juruá Rivers. The small sample size does not allow for a robust conclusion on the possible cause of geographic variation. The distribution of morphological patterns of C. hortullanus in the Amazon Basin suggest that there is gene flow between populations, regardless of geographical distance and natural barriers. The variation in color pattern and markings may represent a phenotypic response to the characteristics of different habitats occupied by the species.

Analysis of exploratory eye movements in patients with schizophrenia during visual scanning of projective tests' figures

OBJECTIVE: Compare pattern of exploratory eye movements during visual scanning of the Rorschach and TAT test cards in people with schizophrenia and controls. METHOD: 10 participants with schizophrenia and 10 controls matched by age, schooling and intellectual level participated in the study. Severity of symptoms was evaluated with the Positive and Negative Syndrome Scale. Test cards were divided into three groups: TAT cards with scenes content, TAT cards with interaction content (TAT-faces), and Rorschach cards with abstract images. Eye movements were analyzed for: total number, duration and location of fixation; and length of saccadic movements. RESULTS: Different pattern of eye movement was found, with schizophrenia participants showing lower number of fixations but longer fixation duration in Rorschach cards and TAT-faces. The biggest difference was observed in Rorschach, followed by TAT-faces and TAT-scene cards. CONCLUSIONS: Results suggest alteration in visual exploration mechanisms possibly related to integration of abstract visual information.

Female gender but not season of birth is associated with mood seasonality in a near-equatorial Brazilian city

OBJECTIVE: Studies conducted mainly in countries located in the Northern Hemisphere have shown that season of birth influences mood seasonality. Greater mood seasonality has been observed for individuals born during spring/summer months than those born during autumn/winter months. Expanding past research to the Southern Hemisphere, in this study we examine the influence of season of birth on mood seasonality in a sample of 1,247 healthy young Brazilians. METHOD: The Seasonal Pattern Assessment Questionnaire was used to compute a global seasonality score as a measure of mood seasonality in a cross-sectional study. RESULTS: Analysis of covariance was conducted to examine the effects of month of birth and gender on mood seasonality, with age entered as a covariate. A main effect of gender was observed, F (1, 1197) = 17.86, p < .01; partial Eta-squared = .02, with mood seasonality being higher for females (M = 8) than for males (M = 7). Contradicting previous findings, no significant main effect for month of birth was observed, F (1, 1197) = 0.65, p > .05. CONCLUSION: The unexpected finding is tentatively explained by differences in geographic location and weather fluctuations between the sampling location in Brazil and other countries where season of birth has been found to influence mood seasonality. Additional studies with larger samples from the Southern Hemisphere are necessary to shed additional light on the possible significant influence of season of birth on mood.

Cognitive processes affect the gait of subjects with Parkinson’s and Alzheimer’s disease in dual tasks

Objective To investigate the relation between gait parameters and cognitive impairments in subjects with Parkinson’s disease (PD) and Alzheimer’s disease (AD) during the performance of dual tasks. Methods This was a cross-sectional study involving 126 subjects divided into three groups: Parkinson group (n = 43), Alzheimer group (n = 38), and control group (n = 45). The subjects were evaluated using the Timed Up and Go test administered with motor and cognitive distracters. Gait analyses consisted of cadence and speed measurements, with cognitive functions being assessed by the Brief Cognitive Screening Battery and the Clock Drawing Test. Statistical procedures included mixed-design analyses of variance to observe the gait patterns between groups and tasks and the linear regression model to investigate the influence of cognitive functions in this process. A 5% significant level was adopted. Results Regarding the subjects’ speed, the data show a significant difference between group vs task interaction (p = 0.009), with worse performance of subjects with PD in motor dual task and of subjects with AD in cognitive dual task. With respect to cadence, no statistical differences was seen between group vs task interaction (p = 0.105), showing low interference of the clinical conditions on such parameter. The linear regression model showed that up to 45.79%, of the variance in gait can be explained by the interference of cognitive processes. Conclusion Dual task activities affect gait pattern in subjects with PD and AD. Differences between groups reflect peculiarities of each disease and show a direct interference of cognitive processes on complex tasks.

Trends in mortality due to ischemic heart disease in the municipality of Goiania, Brazil, during the years between 1980 and 1994

OBJECTIVE: To analyze the trends of specific, standardized coefficients of mortality due to ischemic heart disease according to sex and age during the years 1980 and 1994 in the municipality of Goiania, GO, Brazil. METHODS: Data on deaths were retrieved from the Information on Mortality System of the Ministry of Health; population data were obtained from the Foundation of the Brazilian Institute for Geography and Statistics (IBGE). The trends of the specific coefficients were analyzed by triennia of the historical series, including individuals of both sexes from 25 years of age on, partitioned into 6 age groups of ten years intervals. The population data corresponding to the year 1980 were used as the standard for the calculation of each age group coefficient. Analyses were carried out by straight linear regression. RESULTS: Coefficients were greater for males in each triennium of the series and increased with age in both sexes. The study of the trends of the specific age coefficients of both sexes revealed a stable pattern of evolution up to the age of 65-74 years (P>0.05). From 75 years on, a clear-cut decline in mortality due to ischemic heart disease was shown by both sexes. The standardized coefficients also showed a significant decline (p<=0.05). CONCLUSION: The municipality of Goiânia is at present in a stage of epidemiological transition similar to that of developed countries, even though the observed decline is predominantly influenced by the mortality of older individuals (75 years of age or older).

Changes in the profile of lipoprotein subfractions associated with hormone replacement therapy

OBJECTIVE: To report the effects of 2 regimens of hormone replacement therapy during the postmenopausal period on the profile of the major lipoprotein subfractions (HDL, LDL, and VLDL). METHODS: We carried out a cohort study in 38 postmenopausal patients who were starting their hormone replacement therapy due to gynecological indications, for a period of 12 weeks. Analysis of lipoprotein subclasses was performed through nuclear magnetic resonance spectroscopy. RESULTS: Hormone replacement therapy cause an increase in the proportion of larger subfractions of VLDL and HDL (p=0.008 and 0.03, respectively) and in the proportion of larger particles of VLDL due to a 36% increase in the levels of larger particles (p=0.004), concomitantly with a 15% reduction in the levels of smaller particles (p=0.04). In regard to HDL, the increase occurred only a 17% increase in the levels of larger particles (p=0.002). No significant change occurred in the distribution pattern of LDL subfractions. CONCLUSION: The proportion of larger subfractions of VLDL and HDL increases after hormone replacement therapy. The increase in the proportion of larger particles of VLDL occurs due to an increase in the levels of the larger subclasses concomitantly with a reduction in the smaller particles. However, an increase in the proportion of larger particles of HDL occurs only due to an increase in the levels of the larger subfractions.

Diagnostic value of the tilt-table test for the assessment of syncope in children and adolescents

OBJECTIVE - To assess the diagnostic value, the characteristics, and feasibility of tilt-table testing in children and adolescents. METHODS - From August 1991 to June 1997, we retrospectively assessed 94 patients under the age of 18 years who had a history of recurring syncope and presyncope of unknown origin and who were referred for tilt-table testing. These patients were divided into 2 groups: group I (children) - 36 patients with ages ranging from 3 to 12 (mean of 9.19±2.31) years; group II (adolescents) - 58 patients with ages ranging from 13 to 18 (mean of 16.05±1.40) years. We compared the positivity rate, the type of hemodynamic response, and the time period required for the test to become positive in the 2 groups. RESULTS - The positivity rates were 41.6 % and 50% for groups I and II, respectively. The pattern of positive hemodynamic response that predominated in both groups was the mixed response. The mean time period required for the test to become positive was shorter in group I (11.0±7.23 min) than in group II (18.44±7.83 min). No patient experienced technical difficulty or complications. CONCLUSION - No difference was observed in regard to feasibility, positivity rate, and pattern of positive response for the tilt-table test in children and adolescents. Pediatric patients had earlier positive responses.