Emergence of Hierarchy on a Network of Complementary Agents

Complementarity is one of the main features underlying the interactions in biological and biochemical systems. Inspired by those systems we propose a model for the dynamical evolution of a system composed by agents that interact due to their complementary attributes rather than their similarities. Each agent is represented by a bit-string and has an activity associated to it; the coupling among complementary peers depends on their activity. The connectivity of the system changes in time respecting the constraint of complementarity. We observe the formation of a network of active agents whose stability depends on the rate at which activity diffuses in the system. The model exhibits a non-equilibrium phase transition between the ordered phase, where a stable network is generated, and a disordered phase characterized by the absence of correlation among the agents. The ordered phase exhibits multi-modal distributions of connectivity and activity, indicating a hierarchy of interaction among different populations characterized by different degrees of activity. This model may be used to study the hierarchy observed in social organizations as well as in business and other networks.Comment: 13 pages, 4 figures, submitte

Aplicação da PCAM e da análise de agrupamento em clones de cupuaçuzeiro.

O objetivo deste trabalho foi estudar a divergência genética de 50 clones de cupuaçuzeiro, por meio da PCAM e da Análise de Agrupament

Exploratory research analysis on emissions generated in internal combustion engines

It is common knowledge that internal combustion engines have the function of transforming thermal energy into useful mechanical work. During the combustion process of the fuel and air mixture (heat generation) a quantity of gases are produced and released into the environment by the exhaust system of these engines. When these machines were invented, their creators might not have had the notion that the generated gases would be aggressors to nature. The constant population growth, the increasing demand for the use of these engines and observations of the impact in nature, among them the health and greenhouse effects, evidenced mainly from the end of the last century, led scientists to study the problem related to gaseous emissions from these machines. The present work aims to study and evaluate the emissions of internal combustion engines, their consequences both to the human health and to the environment, the evolution of government legislation and also the control mechanisms implemented to reduce these pollutants. The applied methodology is a qualitative and exploratory study of bibliographic character of theoretical and experimental works that were presented in master's dissertations, doctoral theses, scientific articles and websites of companies specialized in the subject

Avaliação do uso de diferentes tipos de sacos de tecido para incubação in vitro de amostras vegetais.

Resumo: Avaliou-se o potencial de uso de sacos de tecido com diferentes características e porosidades para acondicionamento de amostras em ensaios de produção de gases in vitro. Para isso, amostras de feno de capim coastcross (Cynodon sp.), secas em estufa de ventilação forçada e trituradas (1 mm) foram incubadas durante 96 horas em frascos de vidro com 160 mL de capacidade, contendo 72 mL de meio de cultura e 8 mL de inóculo ruminal. O substrato foi incubado, em quadruplicata, diretamente no frasco de fermentação (controle) ou acondicionado em 3 tipos de saco de tecido: ANKOM filter bag (modelo F57, porosidade = 25 ?m); saco de poliéster (3,5 × 8,0 cm) com porosidade de 25 ?m; saco de poliéster (3,5 × 8,0 cm) com porosidade de 40 ?m. Os valores de degradabilidade da matéria seca não diferiram entre os tratamentos após 96 horas de incubação (P>0,05). A produção acumulada de gases, no entanto, foi 12% inferior ao controle quando o substrato foi incubado em saco de poliéster com porosidade de 40 ?m (P0.05). Total gas production, however, was 12% lower for the substrate incubated in 40-?m polyester bags in comparison to the control (P<0.05). Enclosing samples in cloth bags altered the fermentation kinetic of the incubated substrate, mainly in regard to the rate of gas production (P<0.05). Such alterations were significantly greater when using ANKOM F57 filter bags (P<0.05). Enclosing samples in cloth bags is not appropriate to estimate fermentation kinetic parameters by using the gas production technique

Immunoallergic Disorders in the Elderly

Although allergic diseases have become increasingly prevalent in the elderly, there are few data on this population. Through a retrospective analysis of the electronic medical records of patients aged 65 years and above followed in our Immunoallergology Unit, we aimed to characterize the immunoallergic diseases of the elderly. The most common disorders were respiratory diseases (n = 185; 50%), mucocutaneous diseases (n = 113; 31%), drug allergy (n = 31; 8%), food allergy (n = 9; 2%), and anaphylaxis (n = 9; 2%). Use of specific immunotherapy was residual (n = 2; 1%). There was an association between anaphylaxis and both, drug (p = 0.004) and food (p = 0.013) allergies. Non-allergic rhinitis and bronchial asthma were more frequent in females, and ACE inhibitors/ARB induced-angioedema in males. Recognizing the characteristics of immunoallergic diseases in the elderly and the specificities of this age group is paramount in providing these patients with the best possible care.info:eu-repo/semantics/publishedVersio

Physical aerosol properties and their relation to air mass origin at Monte Cimone (Italy) during the first MINATROC campaign

Aerosol physical properties were measured at the Monte Cimone Observatory (Italy) from 1 June till 6 July 2000. The measurement site is located in the transition zone between the continental boundary layer and the free troposphere (FT), at the border between the Mediterranean area and Central Europe, and is exposed to a variety of air masses. Sub-&mu;m number size distributions, aerosol hygroscopicity near 90% RH, refractory size distribution at 270&deg;C and equivalent black carbon mass were continuously measured. Number size distributions and hygroscopic properties indicate that the site is exposed to aged continental air masses, however during daytime it is also affected by upslope winds. The mixing of this transported polluted boundary layer air masses with relatively clean FT air leads to frequent nucleation events around local noon. <P style='line-height: 20px;'> Night-time size distributions, including fine and coarse fractions for each air mass episode, have been parameterized by a 3-modal lognormal distribution. Number and volume concentrations in the sub-&mu;m modes are strongly affected by the air mass origin, with highest levels in NW-European air masses, versus very clean, free tropospheric air coming from the N-European sector. During a brief but distinct dust episode, the coarse mode is clearly enhanced. <P style='line-height: 20px;'> The observed hygroscopic behavior of the aerosol is consistent with the chemical composition described by Putaud et al.&nbsp;(2004), but no closure between known chemical composition and measured hygroscopicity could be made because the hygroscopic properties of the water-soluble organic matter (WSOM) are not known. The data suggest that WSOM is slightly-to-moderately hygroscopic (hygroscopic growth factor GF at 90% relative humidity between 1.05 and 1.51), and that this property may well depend on the air mass origin and history. <P style='line-height: 20px;'> External mixing of aerosol particles is observed in all air masses through the occurrence of two hygroscopicity modes (average GF of 1.22 and 1.37, respectively). However, the presence of 'less' hygroscopic particles has mostly such a low occurrence rate that the average growth factor distribution for each air mass sector actually appears as a single mode. This is not the case for the dust episode, where the external mixing between less hygroscopic and more hygroscopic particles is very prominent, and indicating clearly the occurrence of a dust accumulation mode, extending down to 50 nm particles, along with an anthropogenic pollution mode. <P style='line-height: 20px;'> The presented physical measurements finally allow us to provide a partitioning of the sub-&mu;m aerosol in four non-overlapping fractions (soluble/volatile, non-soluble/volatile, refractory/non-black carbon, black carbon) which can be associated with separate groups of chemical compounds determined with chemical-analytical techniques (ions, non-water soluble organic matter, dust, elemental carbon). All air masses except the free-tropospheric N-European and Dust episodes show a similar composition within the uncertainty of the data (53%, 37%, 5% and 5% respectively for the four defined fractions). Compared to these sectors, the dust episode shows a clearly enhanced refractory-non-BC fraction (17%), attributed to dust in the accumulation mode, whereas for the very clean N-EUR sector, the total refractory fraction is 25%, of which 13% non-BC and 12% BC

A genetic toolkit and gene switches to limit Mycoplasma growth for biosafety applications

Mycoplasmas have exceptionally streamlined genomes and are strongly adapted to their many hosts, which provide them with essential nutrients. Owing to their relative genomic simplicity, Mycoplasmas have been used to develop chassis for biotechnological applications. However, the dearth of robust and precise toolkits for genomic manipulation and tight regulation has hindered any substantial advance. Herein we describe the construction of a robust genetic toolkit for M. pneumoniae, and its successful deployment to engineer synthetic gene switches that control and limit Mycoplasma growth, for biosafety containment applications. We found these synthetic gene circuits to be stable and robust in the long-term, in the context of a minimal cell. With this work, we lay a foundation to develop viable and robust biosafety systems to exploit a synthetic Mycoplasma chassis for live attenuated vectors for therapeutic applications

Net cage tambaqui farming: microbiological quality, nutritional value and yield.

Tambaqui is traditionally consumed at a commercial size of 1.0 to 3.0 kg However, it is also consumed at between 0.350 to 0.450 kg, this size being referred to as tambaqui curumim (C). The objective of this study was to evaluate the microbiological quality of tambaqui at the commercial size (CS) and to characterize the nutritional value and yield of tambaqui belonging to the two size classes Curumim and CS originating from net cages. The effect of size on the centesimal composition and fish yield was evaluated in a completely randomized design with 12 repetitions while for the microbiological analysis one fish from each net cage was used. C showed protein, ash and moisture contents above those of CS, whereas the ether extract was higher for CS. The yields were 70.04% for C and 65.55% for CS. 50% of the samples showed contamination by Staphylococcus aureus, all values being within the Brazilian?s regulation limits. Salmonella spp. was found in 91.67% of the samples while 75% showed contamination by total coliforms and 8.34% by Escherichia coli. C showed a suitable nutritional value and a better yield in relation to CS. The addition of C to the diet will depend on its acceptance in the markets where its commercialization is not yet established. The microbiological results suggest a tendency of the species to harbor Salmonella spp. on the body surface

Predição da massa corporal em pequenos ruminantes por meio de medidas morfométricas.

A determinação da massa corporal é importante para o melhoramento genético e para os manejos nutricional, reprodutivo e sanitário. Todavia, a inexistência de balanças em grande parte das propriedades rurais dificulta a coleta dessa informação. Assim, esse estudo teve como objetivo determinar a relação entre medidas morfométricas e a massa corporal para servir de base para o desenvolvimento de uma ferramenta de estimativa da massa baseada em mensurações corporais