409 research outputs found
Liquid Polymorphism and Double Criticality in a Lattice Gas Model
We analyze the possible phase diagrams of a simple model for an associating
liquid proposed previously. Our two-dimensional lattice model combines
oreintati onal ice-like interactions and \"{}Van der Waals\"{} interactions
which may be repulsive, and in this case represent a penalty for distortion of
hydrogen bonds in the presence of extra molecules. These interactions can be
interpreted in terms of two competing distances, but not necessarily soft-core.
We present mean -field calculations and an exhaustive simulation study for
different parameters which represent relative strength of the bonding
interaction to the energy penalty for its distortion. As this ratio decreases,
a smooth disappearance of the doubl e criticality occurs. Possible connections
to liquid-liquid transitions of molecul ar liquids are suggested
Relationship among oral habits, orofacial function and oral health-related quality of life in children
Assessment of schistosomiasis, through school surveys, in the Forest Zone of Pernambuco, Brazil
Culture-area relation in Axelrod's model for culture dissemination
Axelrod's model for culture dissemination offers a nontrivial answer to the
question of why there is cultural diversity given that people's beliefs have a
tendency to become more similar to each other's as people interact repeatedly.
The answer depends on the two control parameters of the model, namely, the
number of cultural features that characterize each agent, and the number
of traits that each feature can take on, as well as on the size of the
territory or, equivalently, on the number of interacting agents. Here we
investigate the dependence of the number of distinct coexisting cultures on
the area in Axelrod's model -- the culture-area relationship -- through
extensive Monte Carlo simulations. We find a non-monotonous culture-area
relation, for which the number of cultures decreases when the area grows beyond
a certain size, provided that is smaller than a threshold value and . In the limit of infinite area, this threshold value
signals the onset of a discontinuous transition between a globalized regime
marked by a uniform culture (C=1), and a completely polarized regime where all
possible cultures coexist. Otherwise the culture-area relation
exhibits the typical behavior of the species-area relation, i.e., a
monotonically increasing curve the slope of which is steep at first and
steadily levels off at some maximum diversity value
A Rationale for Schistosomiasis Control in Elementary Schools of the Rainforest Zone of Pernambuco, Brazil
In 2001, a World Health Assembly resolution urged member states to ensure treatment against schistosomiasis and soil-transmitted helminthiasis in endemic areas with the goal of attaining a minimum target of at least 75% of all school-aged children by 2010. In the highly endemic Rainforest Zone of Pernambuco (ZMP), northeast Brazil, the Schistosomiasis Control Program has registered a cumulative coverage of only 20% of the population at risk, which jeopardizes the accomplishment of the minimum target for that area. Demographic and parasitological data from a representative municipality of the ZMP provide evidence that the current, community-based approach to control can be complemented with school-based actions. In the most troubled municipalities, individual diagnosis and treatment could be focused on school-aged children rather than whole populations without compromising the principles of the primary health care system. Local health and education teams should be encouraged to include school-based interventions to scale up coverage and achieve a rapid impact on infection
Schistosomiasis mansoni in Bananal (State of São Paulo, Brazil): IV. Study on the public awareness of its risks in the Palha District
Factors related to transmission of and infection with Schistosoma mansoni in a village in the South-eastern Region of Brazil
First report on dung beetles in intra-Amazonian savannahs in Roraima, Brazil
This is the first study to address the dung beetle (Coleoptera: Scarabaeidae: Scarabaeinae) diversity in intra-Amazonian savannahs in the state of Roraima, Brazil. Our aim was to survey the dung beetle fauna associated with these savannahs (regionally called 'lavrado'), since little is known about the dung beetles from this environment. We conducted three field samples using pitfall traps baited with human dung in savannah areas near the city of Boa Vista during the rainy seasons of 1996, 1997, and 2008. We collected 383 individuals from ten species, wherein six have no previous record in intra-Amazonian savannahs. The most abundant species were Ontherus appendiculatus (Mannerheim, 1829), Canthidium aff. humerale (Germar, 1813), Dichotomius nisus (Olivier, 1789), and Pseudocanthon aff. xanthurus (Blanchard, 1846). We believe that knowing the dung beetles diversity associated with the intra-Amazonian savannahs is ideal for understanding the occurrence and distribution of these organisms in a highly threatened environment, it thus being the first step towards conservation strategy development
The development and psychometric properties of the Arabic version of the child oral health impact profile-short form (COHIP- SF 19)
BACKGROUND: This study aims to cross-culturally adapt the original English-language COHIP-SF 19 to Arabic culture and to test its psychometric properties in a community sample. METHODS: The Arabic COHIP-SF 19 was developed and its psychometric properties were examined in a population-based sample of 876 schoolchildren who were aged 12 years of age, in Benghazi, Libya. The Arabic COHIP-SF 19 was tested for its internal consistency, reproducibility, construct validity, factorial validity and floor as well as ceiling effects. A Mann-Whitney U test was used to compare the mean scores of COHIP-SF 19 by participants' caries status and self-reported oral health rating, satisfaction and treatment need. RESULTS: The Arabic COHIP-SF 19 was successfully and smoothly developed. It showed an acceptable level of equivalence to the original version. Overall, the internal consistency and reproducibility were acceptable to excellent, with a Cronbach's alpha of 0.84 and an intra-class correlation coefficient (ICC) of 0.76. All hypotheses predefined to test construct validity were confirmed. That is, children who had active dental caries, and who rated their oral health as poor, were not satisfied with their oral health or indicated the need of treatment had lower COHIP-SF 19 scores (P < 0.05). Floor or ceiling effects were not observed. The exploratory Factorial analysis suggested a 4-component solution and deletion of one item. CONCLUSION: The Arabic COHIP-SF 19 was successfully developed. The measure demonstrated satisfactory reliability and validity to estimate OHRQoL in a representative sample of 12-year-old schoolchildren
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