Tactical Voting in Plurality Elections

How often will elections end in landslides? What is the probability for a head-to-head race? Analyzing ballot results from several large countries rather anomalous and yet unexplained distributions have been observed. We identify tactical voting as the driving ingredient for the anomalies and introduce a model to study its effect on plurality elections, characterized by the relative strength of the feedback from polls and the pairwise interaction between individuals in the society. With this model it becomes possible to explain the polarization of votes between two candidates, understand the small margin of victories frequently observed for different elections, and analyze the polls'' impact in American, Canadian, and Brazilian ballots. Moreover, the model reproduces, quantitatively, the distribution of votes obtained in the Brazilian mayor elections with two, three, and four candidates.     

Acid hydrolases in the perinuclear secretion granules of the rat preputial gland. A light and electron microscope study

Synopsis Four acid hydrolases in the secretory cells and the sebum of the preputial sebaceous gland of the rat were incestigated cytochemically. A strong -glucuronidase activity was found to occur in the matrix of the perinuclear secretion granules, whereas the granule crystalloids were unreactive. The distribution of acid phosphatase at the light microscope level was similar, though the intensity of the reaction was lower and the number of positive granules smaller. By electron microscopy, the final reaction product of acid phosphatase occurred in patches at the periphery of the granule matrix, as well as in the vesicles adjoining the Golgi stacks, from which the perinuclear granules seemed to arise. In the sebum, the two hydrolases occurred in the background material between the unstained crystalloid masses. There was noN-acetyl--glucosaminidase or aryl sulphatase activity in the gland. The perinuclear granules appear to be secretory lysosomes which, after discharge from the disaggregating cell, release their acid hydrolases into the sebum.     

An electron microscope autoradiographic study of DOC conversion to corticosterone in the rat adrenal cortex

Summary Seven thymuses from children between 1 and 12 years were examined by electron microscopy. Biopsies had been taken during surgical correction of congenital heart defects.In all cases we found interdigitating reticulum cells (IRC) in the medulla and inner cortex. These cells resembled the IRC which have been described previously in the thymus-dependent regions of the spleen and lymph node. They were characterized by an irregularly shaped nucleus, narrow cisterns of rough endoplasmic reticulum, and widespread interdigitation and invagination of the cell membrane. The surfaces of the IRC were in close contact with those of small lymphocytes, sometimes polysomal lymphatic cells, epithelial cells, and occasionally with those of lymphatic cells containing ergastoplasm.The IRC is apparently a specific cell of thymus-dependent regions. It may be that the IRC in the thymus, lymph node, and spleen contribute to the microenvironment needed for the differentiation of T-cells.Supported by the Deutsche Forschungsgemeinschaft, SFB 111/CII and III.—We wish to thank Miss M. Neubert and Mrs. R. Köpke for their technical assistance and Mrs. M. Soehring for her help with the translation.     

Modeling competition between Laurencia obtusa (Ceramiales,Rhodophyta) and Hypnea spinella (Gigartinales,Rhodophyta) at Cabo Frio Island,Rio de Janeiro,Brazil

The Lotka-Volterra competition model was used to represent the interaction between Laurencia obtusa and Hypnea spinella. A new model that considers effects of competition on algal carrying capacity is suggested. To test the models, data from field experiments conducted in an intertidal region at Cabo Frio Island, Rio de Janeiro, Brazil, were used. Both models showed that Hypnea was a stronger competitor than Laurencia. The model of interaction through the carrying capacity showed a stable coexistence between the algal populations and better represented the experimental data.     

Calcium exchanges in Anodonta cygnea: barriers and driving gradients

Electrical potential differences between the haemolymph and the extrapallial fluid, and between the haemolymph and the mantle cavity fluid, and ionic concentrations of calcium in the haemolymph and in extrapallial fluid were measured in vivo in Anodonta cygnea. The electrochemical potential of ionic calcium in the haemolymph is clearly above the electrochemical potential of ionic calcium in the environment and is very nearly in equilibrium with that of the extrapallial fluid. Simultaneous measurements of carbon dioxide partial pressure and pH in the extrapallial fluid showed that in this compartment ionic calcium is clearly above saturation. It is proposed that calcium deposition is regulated through the secretion of the organic matrix and by controlling the pH and the carbon dioxide partial pressure of the extrapallial fluid. An estimation of the minimum positive balance of calcium required to sustain shell growth together with the electrophysiological characterization of the mantle cavity epithelium showed that this tissue is not the route of entry of calcium into the animal.Abbreviations BW body weight - DW dry weight - E_EPF-S chemical potential difference - EPF extrapallial fluid - G_tot total conductance - I_sc short-circuit current - K_sp solubility product - MCE mantle cavity epithelium - MCF mantle cavity fluid - OME outer mantle epithelium - PCO₂ partial pressure of carbon dioxide - PVC Poly(vinyl chloride) - S shell - SEM standard error of mean - V _ic intracellular electrical potential - V _oc open-circuit voltage     

Ecosystem-level effects of re-oligotrophication and N:P imbalances in rivers and estuaries on a global scale

Trends and ecological consequences of phosphorus (P) decline and increasing nitrogen (N) to phosphorus (N:P) ratios in rivers and estuaries are reviewed and discussed. Results suggest that re-oligotrophication is a dominant trend in rivers and estuaries of high-income countries in the last two–three decades, while in low-income countries widespread eutrophication occurs. The decline in P is well documented in hundreds of rivers of United States and the European Union, but the biotic response of rivers and estuaries besides phytoplankton decline such as trends in phytoplankton composition, changes in primary production, ecosystem shifts, cascading effects, changes in ecosystem metabolism, etc., have not been sufficiently monitored and investigated, neither the effects of N:P imbalance. N:P imbalance has significant ecological effects that need to be further investigated. There is a growing number of cases in which phytoplankton biomass have been shown to decrease due to re-oligotrophication, but the potential regime shift from phytoplankton to macrophyte dominance described in shallow lakes has been documented only in a few rivers and estuaries yet. The main reasons why regime shifts are rarely described in rivers and estuaries are, from one hand the scarcity of data on macrophyte cover trends, and from the other hand physical factors such as peak flows or high turbidity that could prevent a general spread of submerged macrophytes as observed in shallow lakes. Moreover, re-oligotrophication effects on rivers may be different compared to lakes (e.g., lower dominance of macrophytes) or estuaries (e.g., limitation of primary production by N instead of P) or may be dependent on river/estuary type. We conclude that river and estuary re-oligotrophication effects are complex, diverse and still little known, and in some cases are equivalent to those described in shallow lakes, but the regime shift is more likely to occur in mid to high-order rivers and shallow estuaries.     

The detection and attribution of extreme reductions in vegetation growth across the global land surface

Negative extreme anomalies in vegetation growth (NEGs) usually indicate severely impaired ecosystem services. These NEGs can result from diverse natural and anthropogenic causes, especially climate extremes (CEs). However, the relationship between NEGs and many types of CEs remains largely unknown at regional and global scales. Here, with satellite-derived vegetation index data and supporting tree-ring chronologies, we identify periods of NEGs from 1981 to 2015 across the global land surface. We find 70% of these NEGs are attributable to five types of CEs and their combinations, with compound CEs generally more detrimental than individual ones. More importantly, we find that dominant CEs for NEGs vary by biome and region. Specifically, cold and/or wet extremes dominate NEGs in temperate mountains and high latitudes, whereas soil drought and related compound extremes are primarily responsible for NEGs in wet tropical, arid and semi-arid regions. Key characteristics (e.g., the frequency, intensity and duration of CEs, and the vulnerability of vegetation) that determine the dominance of CEs are also region- and biome-dependent. For example, in the wet tropics, dominant individual CEs have both higher intensity and longer duration than non-dominant ones. However, in the dry tropics and some temperate regions, a longer CE duration is more important than higher intensity. Our work provides the first global accounting of the attribution of NEGs to diverse climatic extremes. Our analysis has important implications for developing climate-specific disaster prevention and mitigation plans among different regions of the globe in a changing climate.     

Socioeconomic transition and physical growth of Tupí-Mondê Amerindian children of the Aripuan? Park, Brazilian Amazon

Anthropometric assessment of nutritional status is reported for three Tupí-Mondê-speaking groups from Rond?nia and Mato Grosso, Brazil. This region of the Amazon basin is experiencing rapid development through government-oriented colonization. The Gavi?o, Suruí, and Zoró had their first contacts with Brazilian national society at different times, and the nature and degree of their participation in regional markets varies. Height, weight, sitting height, subischial leg length, upper arm circumference, triceps skin-fold thickness, and upper arm muscle and fat areas are reported for children 0-10.9 years of age. Like other Amazonian Amerindians, Tupí-Mondê children are short for their age but normal or above normal in weight for height with respect to the National Center for Health Statistics reference. Hence stunting levels are high (55.4%) and wasting levels are low (0.8%). There are also deficits in body composition parameters, especially in upper arm circumference and estimated muscle and fat areas. We interpret the results as evidence of suboptimal nutritional status, reflecting the interaction between poor diet and infectious and parasitic diseases. The Gavi?o, with the longest period of contact, present the lowest level of stunting. This finding is attributed to the use of cash income from rubber tapping and nut gathering to purchase of food items and health care. Differences in height between the three groups are mostly due to leg length, instead of sitting height, reinforcing the idea that environmental conditions can alter body proportions.