Implications of long-term land-use change for the hydrology and solute budgets of small catchments in Amazonia

The replacement of undisturbed tropical forest with cattle pasture has the potential to greatly modify the hydrology of small watersheds and the fluxes of solutes. We examined the fluxes of water, Cl(-), NO(3)(-)-N: SO(4)(2--)-S, NH(4)(+)-N, Na(+), K(+), Mg(2+) and Ca(2+) in different flow paths in similar to 1 ha catchments of undisturbed open tropical rainforest and a 20 year-old pasture established from forest in the southwestern Brazilian Amazon state of Rondonia. Storm flow discharge was 18% of incident rainfall in pasture, but only 1% in forest. Quickflow predominated over baseflow in both catchments and in both wet and dry seasons. In the pasture, groundwater and quickflow were important flow paths for the export of all solutes. In the forest, quickflow was important for NO(3)(-)-N export, but all other solutes were exported primarily by groundwater outflow. Both catchments were sinks for SO(4)(2-)-S and Ca(2+), and sources of Na(+). The pasture catchment also lost K(+) and Mg(2+) because of higher overland flow frequency and volume and to cattle excrement. These results show that forest clearing dramatically influences small watershed hydrology by increasing quickflow and water export to streams. They also indicate that tropical forest watersheds are highly conservative for most solutes but that pastures continue to lose important cations even decades after deforestation and pasture establishment. (c) 2008 Elsevier B.V. All rights reserved.

Runoff sources and land cover change in the Amazon: an end-member mixing analysis from small watersheds

The flowpaths by which water moves from watersheds to streams has important consequences for the runoff dynamics and biogeochemistry of surface waters in the Amazon Basin. The clearing of Amazon forest to cattle pasture has the potential to change runoff sources to streams by shifting runoff to more surficial flow pathways. We applied end-member mixing analysis (EMMA) to 10 small watersheds throughout the Amazon in which solute composition of streamwater and groundwater, overland flow, soil solution, throughfall and rainwater were measured, largely as part of the Large-Scale Biosphere-Atmosphere Experiment in Amazonia. We found a range in the extent to which streamwater samples fell within the mixing space determined by potential flowpath end-members, suggesting that some water sources to streams were not sampled. The contribution of overland flow as a source of stream flow was greater in pasture watersheds than in forest watersheds of comparable size. Increases in overland flow contribution to pasture streams ranged in some cases from 0% in forest to 27-28% in pasture and were broadly consistent with results from hydrometric sampling of Amazon forest and pasture watersheds that indicate 17- to 18-fold increase in the overland flow contribution to stream flow in pastures. In forest, overland flow was an important contribution to stream flow (45-57%) in ephemeral streams where flows were dominated by stormflow. Overland flow contribution to stream flow decreased in importance with increasing watershed area, from 21 to 57% in forest and 60-89% in pasture watersheds of less than 10 ha to 0% in forest and 27-28% in pastures in watersheds greater than 100 ha. Soil solution contributions to stream flow were similar across watershed area and groundwater inputs generally increased in proportion to decreases in overland flow. Application of EMMA across multiple watersheds indicated patterns across gradients of stream size and land cover that were consistent with patterns determined by detailed hydrometric sampling.

Change in central kinin B2 receptor density after exercise training in rats

Cardiovascular responses elicited by the stimulation of kinin B2 receptors in the IV cerebral ventricle paratrigeminal nucleus or in the thoracic spinal cord are similar to those observed during an exercise bout Considering that the kalikrein-kinin system (KKS) could act on the cardiovascular modulation during behavioral responses as physical exercise or stress this study evaluated the central B2 receptor densities of Wistar (W) and spontani ously hypertensive rats (SHR) after chronic moderate exercise Animals we re exercise-trained for ten weeks on a treadmill Afterwards systolic blood pressure decreased in both trained strains Animals were killed and the medulla and spinal cord extracted for B2 receptor autoradiography Trained animals were compared to their sedentary controls Sedentary groups showed specific binding sites for Hoe-140 (fmol/mg of tissue) in laminas 1 and 2 of the spinal cord nucleus of the solitary tract (NTS) area postrema (AP) spinal trigeminal tract (sp5) and paratrigeminal nucleus (Pa5) In trained W a significant increase (p<0 05) in specific binding was observed in the Pa5 (31 3%) and NTS (28 2%) Trained SHR showed a significant decrease in n ceptor density in lamina 2 (21 9%) of the thoracic spinal cord and an increase in specific binding in Pa5 (36 1%) We suggest that in the medulla chronic exercise could hyper stimulate the KKS enhancing their efficiency through the increase of B2 receptor density involving this receptor in central cardiovascular control during exercise or stress In the lamina 2 B2 receptor might be involved in the exercise-induced hypotension (C) 2010 Elsevier BV All rights reserved

Experimental Analysis of Structural Change and Rheological Behavior of Macromolecular Solutions with Guar and Xanthan Gums in Crossflow Microfiltration Processing

The present paper reports on the structural change and rheological behavior of mixtures of macromolecular suspensions (guar and xanthan gums) in crossflow microfiltration processing. Mixtures in suspension of guar and xanthan gums at low concentrations (1,000 ppm) and different proportions were processed by microfiltration with membrane of nominal pore size of 0.4 mu m. The rheological behavior of the mixtures was investigated in rotational viscometers at two different temperatures, 25 and 40 C, at the beginning and at the end of each experiment. The shear stress (t) in function of the shear rate (gamma) was fitted and analyzed with the power-law model. All the mixtures showed flow behavior index values (n) lower than 1, characterizing non-Newtonian fluids (pseudoplastic). The samples of both mixtures and permeates were also analyzed by absorbency spectroscopy in infrared radiation. The absorbency analysis showed that there is good synergism between xanthan and guar gums without structure modifications or gel formation in the concentration process by microfiltration.

A discussion on volume change in the plastic phase

This technical note discusses the possibility of using a more simplified scheme to estimate the plastic multiplier when some material shows volume changes, e.g. soil, balsa wood foam and other similar materials. Two procedures regarding volume changes during the plastic phase are discussed here. The first one is the classic procedure applied to non-associative plasticity, for which a Drucker-Prager-like surface is adopted to represent the plastic potential. For the second procedure, the plastic potential is not explicitly known, however, its orthogonal direction is chosen respecting a plastic volume change parameter similar to Poisson`s ratio. Copyright (C) 2007 John Wiley & Sons, Ltd.

Natural and human forcing in recent geomorphic change; case studies in the Rio de la Plata basin

An analysis of geomorphic system`s response to change in human and natural drivers in some areas within the Rio de la Plata basin is presented The aim is to determine whether an acceleration of geomorphic processes has taken place in recent years and, if so, to what extent it is due to natural (climate) or human (land-use) drivers Study areas of different size, socio-economic and geomorphic conditions have been selected: the Rio de la Plata estuary and three sub-basins within its watershed Sediment cores were extracted and dated ((210)Pb) to determine sedimentation rates since the end of the 19th century. Rates were compared with time series on rainfall as well as human drivers such as population, GDP, livestock load, crop area, energy consumption or cement consumption, all of them related to human capacity to disturb land surface Data on river discharge were also gathered Results obtained indicate that sedimentation rates during the last century have remained essentially constant in a remote Andean basin, whereas they show important increases in the other two, particularly one located by the Sao Paulo metropolitan area Rates in the estuary are somewhere in between It appears that there is an intensification of denudation/sedimentation processes within the basin. Rainfall remained stable or varied very slightly during the period analysed and does not seem to explain increases of sedimentation rates observed. Human drivers, particularly those more directly related to capacity to disturb land surface (GDP, energy or cement consumption) show variations that suggest human forcing is a more likely explanation for the observed change in geomorphic processes It appears that a marked increase in denudation, of a ""technological"" nature, is taking place in this basin and leading to an acceleration of sediment supply This is coherent with similar increases observed in other regions (C) 2010 Elsevier B V All rights reserved

Reliability concepts applied to cutting tool change time

This paper presents a reliability-based analysis for calculating critical tool life in machining processes. It is possible to determine the running time for each tool involved in the process by obtaining the operations sequence for the machining procedure. Usually, the reliability of an operation depends on three independent factors: operator, machine-tool and cutting tool. The reliability of a part manufacturing process is mainly determined by the cutting time for each job and by the sequence of operations, defined by the series configuration. An algorithm is presented to define when the cutting tool must be changed. The proposed algorithm is used to evaluate the reliability of a manufacturing process composed of turning and drilling operations. The reliability of the turning operation is modeled based on data presented in the literature, and from experimental results, a statistical distribution of drilling tool wear was defined, and the reliability of the drilling process was modeled. (C) 2010 Elsevier Ltd. All rights reserved.

The synergism between high superficial roughness and corrosive atmosphere in the fatigue behavior of the SAE 1045 steel

The fatigue behavior of the SAE 1045 steel in four different conditions is reported in this paper. Four treatments were tested: polished surface, corrosive atmosphere (sugar cane juice), low quality roughness (typical equivalent surface of the shaft cane mill) and the combined condition of the two last treatments involved. Fatigue tests were performed in rotating bending conditions and the values of fatigue strength for the different situations from tests were obtained. The diminution in fatigue strength for the synergy condition of rough surface and corrosive atmosphere was of 8.7%, result statistically representative with less than 0.01% of uncertainty.

Structural change, balance-of-payments constraint, and economic growth: evidence from the multisectoral Thirlwall`s law

This paper contributes to the literature on balance-of-payments constrained growth by investigating how structural change identified with changes in the sectoral composition of exports and imports affects the external constraint We test both the original and a multisectoral version of Thirlwall`s law for a sample of Latin American and Asian countries The original Thirlwall s law is found to hold for all sample countries except South Korea, whereas the multisectoral analogue holds for all of them As the sectoral composition of exports and imports is found to matter for growth we analyze the evolution of each country`s weighted trade income elasticities

GREEN MANAGEMENT, CLIMATE CHANGE AND SMALL BUSINESS IN BRAZIL: IMPLICATIONS FOR TRAINING AND EDUCATION FOR SUSTAINABLE DEVELOPMENT

This paper presents the results of a study on the analysis of training needs regarding environmental (green) management and climate change topics in micro and small enterprises (MSEs) in Brazil and its implications on education for sustainable development. It reports on an e-mail survey of Brazilian small enterprises, whose results indicate that they are indeed interested in environmental management and climate change topics in an education for sustainable development context. The study indicates that proposals for courses on environmental management and climate change should follow a systemic perspective and take sustainable development into account. By applying factor analysis, it was found that the topics of interest can be grouped into thematic modules, which can be useful in the design of training courses for the top management leaders of those companies.

Parametric change in the grammatical encoding of indirect objects in Brazilian Portuguese

This paper examines the syntax of indirect objects (IO) in Brazilian Portuguese (BP). Adopting a comparative perspective we propose that BP differs from European Portuguese (EP) in the grammatical encoding of IO. In EP ditransitive contexts, IO is found in two configurations - one projected by a (low) applicative head and another one involving a lexical/true preposition. We propose that the former property is contingent upon the presence of dative Case marking: namely, the morpheme `a` that introduces IO (a-DP), whose corresponding clitic pronoun is `lhe/lhes`. In contrast, important changes in the pronominal system, coupled with the increase in the use of the preposition `para` are taken as evidence for the loss of the low applicative construction in BP. Thus only the configuration with the lexical/true preposition is found in (Standard) BP. We argue that the innovative properties of IO in BP are due to the loss of the (3rd person) dative clitic and the preposition `a` as dative Case markers. Under this view, we further account for the realization of IO as a DP/weak pronoun, found in dialects of the central region of Brazil, which points to a similarity with the English Double Object Construction. Finally we show that the connection between the morphological expression of the dative Case and the expression of parameters supports a view of syntactic change according to which parametric variation is determined in the lexicon, in terms of the formal features of functional heads.

Waves of Change Within Civil Society in Latin America: Mexico City and Sao Paulo

For the past half a century, Latin American scholars have been pointing toward the emergence of new social actors as agents of social and political democratization. The first wave of actors was characterized by the emergence of novel agents-mainly, new popular movements-of social transformation. At first, the second wave, epitomized by nongovernmental organizations (NGOs), was celebrated as the upsurge of a new civil society, but later on, it was the target of harsh criticism. The literature often portrays this development in Latin American civil society as a displacement trend of actors of the first wave by the second wave-""NGOization""-""and even denounces new civil society as rootless, depoliticized, and functional to retrenchment. Thus, supposedly, NGOization encumbers social change. The authors argue that NGOization diagnosis is a flawed depiction of change within civil society. Rather than NGOization related to the depoliticization and neoliberalization of civil society, in Mexico City and Sao Paulo, there has been modernization of organizational ecologies, changes in the functional status of civil society, and interestingly, specialization aimed at shaping public agenda. The authors argue that such specialization, instead of encumbering social change, brings about different repertoires of strategies and skills purposively developed for influencing policy and politics. Their argument relies on comparative systematic evidence. Through network analysis, they examine the organizational ecology of civil society in Mexico City and Sao Paulo.

Amino acids change liver growth factors gene expression in malnourished rats

Background: Glutamine and proline are metabolized in the liver and may collaborate on its regeneration. Parenteral nutrition (PN) containing either glutamine or proline was given to partially hepatectomized rats. The total RNA content and growth factor gene expression in hepatic remnants was measured, to determine the effects of these amino acid supplementation on the expression of growth factors during liver regeneration. Methods: Wistar rats nourished (HN) and malnourished (HM) were hepatectomized and divided in two groups: 20 receiving PN enriched with Alanyl-Glutamine (HN-Gln and HM-Gln) and 20 PN enriched with proline+alanine (HN-Pro and HM-Pro). The control groups comprised 7 nourished (CN) and 7 malnourished (CM) rats that didn`t undergo surgery. Growth factor and thymidine kinase mRNA levels were measured by RT-PCR. Results: In nourished rats, total hepatic RNA levels were lower in the HN-Gln and HN-Pro groups (0.75 and 0.63 mu g/mg tissue, respectively) than in control group (1.67 mu g/mg tissue) (P<0.05). In malnourished rats, total hepatic RNA content was higher in the HM-Pro group than FIN-Pro, HM-Gln, and CM (3.18 vs. 0.63, 0.93 and 1.10 mu g/mg, respectively; P<0.05). Hepatocyte growth factor mRNA was more abundant in the HM-Gln group when compared to CM (031 vs. 0.23 arbitrary units) and also in HM-Pro in relation to HM-Gln, HN-Pro, and CM (0.46 vs. 033 and 0.23, respectively, P<0.05). Conclusions: Proline or glutamine supplementation in malnourished rats improves total RNA content in the remnant hepatic tissue. Amino acids administration increased HGF gene expression after partial hepatectomy in malnourished rats, with a greater effect of proline than glutamine.

Microvascular Lymphatic Density Analysis in Cutaneous Regressive and Nonregressive Superficial Spreading Melanomas Using the Lymphatic Marker D2-40

Background: The prognostic significance of spontaneous regression in melanoma, especially thin lesions, has been a controversial issue for the past 20 years, although recent studies suggest that extensive and late regression may be related to worse prognosis. Many data suggest that lymphangiogenesis predicts metastatic spread in melanoma. Methods: We have quantified lymphatic microvascular density (LMVD) in thin (<= 1.0 mm) superficial spreading melanomas comparing regressive and nonregressive melanomas, regressive and nonregressive areas from the same tumor, and early and late histological stages of regression in the same tumor. In addition, we tried to correlate lymphangiogenesis and tumor growth phase. We conducted histological examinations and immunohistochemical analyses using monoclonal antibody D2-40 with subsequent quantification by image analysis of 37 melanomas, 16 regressive and 21 nonregressive (controls). Results: We found higher LMVD in the late stage of regression compared with nonregressive area (internal control) of regressive melanomas. Conclusions: Our study suggest that the late stage of spontaneous regression in thin melanomas may be related to worse prognosis as it showed higher LMVD, and evidence shows that this is related with increased risk of metastatic spread. But this supposition must be confirmed by a longer follow-up for detection of lymph node metastases.