758 resultados para southeastern Pacific


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Time-variable gravity data from the Gravity Recovery And Climate Experiment (GRACE) mission are used to study total water content over Australia for the period 2002–2010. A time-varying annual signal explains 61% of the variance of the data, in good agreement with two independent estimates of the same quantity from hydrological models. Water mass content variations across Australia are linked to Pacific and Indian Ocean variability, associated with El Niño-Southern Oscillation (ENSO) and the Indian Ocean Dipole (IOD), respectively. From 1989, positive (negative) IOD phases were related to anomalously low (high) precipitation in southeastern Australia, associated with a reduced (enhanced) tropical moisture flux. In particular, the sustained water mass content reduction over central and southern regions of Australia during the period 2006–2008 is associated with three consecutive positive IOD events.

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Uniquely in the Southern Hemisphere the New Zealand micro-continent spans the interface between a subtropical gyre and the Subantarctic Circumpolar Current. Its 20° latitudinal extent includes a complex of submerged plateaux, ridges, saddles and basins which, in the present interglacial, are partial barriers to circulation and steer the Subtropical (STF) and Subantarctic (SAF) fronts. This configuration offers a singular opportunity to assess the influence of bottom topography on oceanic circulation through Pleistocene glacial - interglacial (G/I) cycles, its effect on the location and strength of the fronts, and its ability to generate significant differences in mixed layer thermal history over short distances. For this study we use new planktic foraminiferal based sea-surface temperature (SST) estimates spanning the past 1 million years from a latitudinal transect of four deep ocean drilling sites. We conclude that: 1. the effect of the New Zealand landmass was to deflect the water masses south around the bathymetric impediments; 2. the effect of a shallow submerged ridge on the down-current side (Chatham Rise), was to dynamically trap the STF along its crest, in stark contrast to the usual glacial-interglacial (G-I) meridional migration that occurs in the open ocean; 3. the effect of more deeply submerged, downstream plateaux (Campbell, Bounty) was to dynamically trap the SAF along its steep southeastern margin; 4. the effects of saddles across the submarine plateaux was to facilitate the development of jets of subtropical and subantarctic surface water through the fronts, forming localized downstream gyres or eddies during different phases in the G-I climate cycles; 5. the deep Pukaki Saddle across the Campbell-Bounty Plateaux guided a branch of the SAF to flow northwards during each glacial, to form a strong gyre of circumpolar surface water in the Bounty Trough, especially during the mid-Pleistocene Climate Transition (MIS 22-16) when exceptionally high SST gradients existed across the STF; 6. the shallower Mernoo Saddle, at the western end of the Chatham Rise, provided a conduit for subtropical water to jet southwards across the STF in the warmest interglacial peaks (MIS 11, 5.5) and for subantarctic water to flow northwards during glacials; 7. although subtropical or subantarctic drivers can prevail at a particular phase of a G-I cycles, it appears that the Antarctic Circumpolar Current is the main influence on the regional hydrography. Thus complex submarine topography can affect distinct differences in the climate records over short distances with implications for using such records in interpreting global or regional trends. Conversely, the local topography can amplify the paleoclimate record in different ways in different places, thus enhancing its value for the study of more minor paleoceanographic influences that elsewhere are more difficult to detect. Such sites include DSDP 594, which like some other Southern Ocean sites, has the typical late Pleistocene asymmetrical saw-tooth G-I climate pattern transformed to a gap-tooth pattern of quasi-symmetrical interglacial spikes that interrupt extended periods of minimum glacial temperatures.

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Significant uncertainties persist in the reconstruction of past sea surface temperatures in the eastern equatorial Pacific, especially regarding the amplitude of the glacial cooling and the details of the post-glacial warming. Here we present the first regional calibration of alkenone unsaturation in surface sediments versus mean annual sea surface temperatures (maSST). Based on 81 new and 48 previously published data points, it is shown that open ocean samples conform to established global regressions of Uk'37 versus maSST and that there is no systematic bias from seasonality in the production or export of alkenones, or from surface ocean nutrient concentrations or salinity. The flattening of the regression at the highest maSSTs is found to be statistically insignificant. For the near-coastal Peru upwelling zone between 11-15°S and 76-79°W, however, we corroborate earlier observations that Uk'37 SST estimates significantly over-estimate maSSTs at many sites. We posit that this is caused either by uncertainties in the determination of maSSTs in this highly dynamic environment, or by biasing of the alkenone paleothermometer toward El Niño events as postulated by Rein et al. (2005).

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"This study has been made with the cooperation of the Secretariat of the Institute of Pacific relations and constitutes a report in its International research series."

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The aeolid nudibranch Pteraeolidia ianthina hosts symbiotic dinoflagellates in the same way as many reef-building corals. This widespread Indo-Pacific sea slug ranges from tropical to temperate waters, and offers a unique opportunity to examine a symbiosis that occurs over a large latitudinal gradient. We used partial 28S and 18S nuclear ribosomal (nr) DNA to examine the genetic diversity of the Symbiodinium dinoflagellates contained within F ianthina. We detected Symbiodinium from genetic clades A, B, C and D. P. ianthina from tropical regions (Singapore, Sulawesi) host Symbiodinium clade C or D or both; those from the subtropical eastern Australian coast (Heron Island, Mon Repo, Moreton Bay, Tweed Heads) host Symbiodinium clade C, but those from the temperate southeastern Australian coastline (Port Stephens, Bare Island) host clade A or B or both. The Symbiodinium populations within 1 individual nudibranch could be homogeneous or heterogeneous at inter- or intra-clade levels (or both). Our results suggested that the Pteraeolidia-Symbiodinium symbiosis is flexible and favours symbiont phylotypes best adapted for that environment. This flexibility probably reflects the function of the symbiont clade in relation to the changing environments experienced along the latitudinal range, and facilitates the large geographic range of P. ianthina.

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Scorpion stings account for most envenomations by venomous animals in Brazil. A retrospective study (1994-2011) of the clinical consequences of Tityus scorpion stings in 1327 patients treated at a university hospital in Campinas, southeastern Brazil, is reported. The clinical classification, based on outcome, was: dry sting (no envenoming), class I (only local manifestations), class II (systemic manifestations), class III (life-threatening manifestations, such as shock and/or cardiac failure requiring inotropic/vasopressor agents, and/or respiratory failure), and fatal. The median patient age was 27 years (interquartile interval = 15-42 years). Scorpions were brought for identification in 47.2% of cases (Tityus bahiensis 27.7%; Tityus serrulatus 19.5%). Sting severity was classified and each accounted for the following percentage of cases: dry stings - 3.4%, class I - 79.6%, class II - 15.1%, class III - 1.8% and fatal - 0.1%. Pain was the primary local manifestation (95.5%). Systemic manifestations such as vomiting, agitation, sweating, dyspnea, bradycardia, tachycardia, tachypnea, somnolence/lethargy, cutaneous paleness, hypothermia and hypotension were detected in class II or class III + fatal groups, but were significantly more frequent in the latter group. Class III and fatal cases occurred only in children <15 years old, with scorpions being identified in 13/25 cases (T. serrulatus, n = 12; T. bahiensis, n = 1). Laboratory blood abnormalities (hyperglycemia, hypokalemia, leukocytosis, elevations in serum total CK, CK-MB and troponin T, bicarbonate consumption and an increase in base deficit and blood lactate), electrocardiographic changes (ST segment) and echocardiographic alterations (ventricular ejected fraction <54%) were frequently detected in class III patients. Seventeen patients developed pulmonary edema, 16 had cardiac failure and seven had cardiogenic shock. These results indicate that most scorpion stings involved only local manifestations, mainly pain; the greatest severity was associated with stings by T. serrulatus and in children <15 years old.

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To evaluate factors associated with hypertension in Brazilian women of 50 years of age or more. A cross-sectional population based study using self-reports. A total of 622 women were included. The association between sociodemographic, clinical and behavioral factors and the woman's age at the onset of hypertension was evaluated. Data were analyzed according to cumulative continuation rates without hypertension, using the life-table method and considering annual intervals. Next, a Cox multiple regression analysis model was adjusted to analyze the occurrence rates of hypertension according to various predictor variables. Significance level was pre-established at 5% (95% confidence level) and the sampling plan (primary sampling unit) was taken into consideration. Median age at onset of hypertension was 64.3 years. Cumulative continuation rate without hypertension at 90 years was 20%. Higher body mass index (BMI) at 20-30 years of age was associated with a higher cumulative occurrence rate of hypertension over time (coefficient=0.078; p<0.001). Being white was associated with a lower cumulative occurrence rate of hypertension over time (coefficient= -0.439; p=0.003), while smoking >15 cigarettes/day was associated with a higher rate over time (coefficient=0.485; p=0.004). The results of the present study highlight the importance of weight control in young adulthood and of avoiding smoking in preventing hypertension in women aged ≥50 years.

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The aim of this work was to evaluate the floristic composition, richness, and diversity of the upper and lower strata of a stretch of mixed rain forest near the city of Itaberá, in southeastern Brazil. We also investigated the differences between this conservation area and other stretches of mixed rain forest in southern and southeastern Brazil, as well as other nearby forest formations, in terms of their floristic relationships. For our survey of the upper stratum (diameter at breast height [DBH] > 15 cm), we established 50 permanent plots of 10 × 20 m. Within each of those plots, we designated five, randomly located, 1 × 1 m subplots, in order to survey the lower stratum (total height > 30 cm and DBH < 15 cm). In the upper stratum, we sampled 1429 trees and shrubs, belonging to 134 species, 93 genera, and 47 families. In the lower stratum, we sampled 758 trees and shrubs, belonging to 93 species, 66 genera, and 39 families. In our floristic and phytosociological surveys, we recorded 177 species, belonging to 106 genera and 52 families. The Shannon Diversity Index was 4.12 and 3.5 for the upper and lower strata, respectively. Cluster analysis indicated that nearby forest formations had the strongest floristic influence on the study area, which was therefore distinct from other mixed rain forests in southern Brazil and in the Serra da Mantiqueira mountain range.

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Food habits of jaguarundi (Puma yagouaroundi) (Geoffroy, 1803) (Carnivora, Felidae) were studied between November 2000 and November 2001, in a 24.9 km² area of secondary Atlantic Rainforest and eucalypt plantation, in the Serra de Paranapiacaba, São Paulo State, Brazil. Analyses of 26 fecal and regurgitate samples, obtained over a stretch of 570.1 km, showed the consumption of 19 prey items and 74 prey occurrences. Small mammals were the most frequent food item (42.5%), followed by birds (21%), reptiles (14%) and medium-sized mammals (3%). The percent occurrence (PO) suggests that the diet consisted mainly of small rodents (30%) and birds (21%). We recorded for the first time the predation of Viperidae snakes by P. yagouaroundi. Although having a large list of items and range of dietary niche breadths (Bsta = 0.76), our data show that jaguarundi prey mainly on small vertebrates (mammals, birds or reptiles), and even in tall tropical forests or eucalypt plantations, it preys mostly on animals that come to, or live on, the ground.

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A new species of dactylogyrid monogenean, Apedunculata discoidea gen. n., sp. n. is described and illustrated from the gills of the freshwater fish Prochilodus lineatus (Valenciennes, 1837) in pisciculture ponds from Pirassununga, São Paulo, Brazil. Diagnostic characters of the new genus and species are: 1) vagina dextrolateral slightly sclerotised, opening anteriorly at level of copulatory complex; 2) copulatory organ coiled with two counterclockwise rings; 3) Accessory piece distal and not articulated; 4) body disk-shaped, lacking a peduncle.

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OBJECTIVE: This study aimed to asses oral health conditions in a population aged 60 years and over living in Botucatu, Southeastern Brazil. A cross-sectional population-based study was carried out using a random sample (N=372) of the urban population aged 60 years and over from the city of Botucatu, in 2005. World Health Organization criteria and codes for oral health epidemiological surveys were used. Re-examination was carried out in 10% of individuals aiming to evaluate intra-examiner agreement. Statistical analysis was performed by one-way ANOVA or Kruskal-Wallis ANOVA, as applicable. Also, the t-test was used in the absence of homoscedasticity. Fisher's exact test was used for situations where the categories with less than five units were observed. Adjusted residuals and multiple-comparison analysis were conducted to identify associations between variable categories and subgroups. The intra-examiner agreement was 98% and Kappa statistics result was 0.95. Loss component represented 90.68% of DMF-T index, which was 29.85. The prevalence of edentulism was 63.17%. Upper and lower dentures were found in 80% and 58% respectively, with complete denture as the most commonly used. In those studied, 15% required upper and 38% lower dentures. There was more need for complete denture in both jaws. Approximately 20% had soft tissue alterations. For periodontal conditions, most sextants were excluded (81.81%). Periodontal pockets (4 - 5 mm) were seen in 11.29% of the examined individuals. The oral health status of the elderly population in Botucatu is poor, as well as in other Brazilian cities. The results of this study may help planning collective health actions, giving an accurate description of the oral problems among the elderly.