228 research outputs found
Editorial: Freshwater biodiversity crisis: Multidisciplinary approaches as tools for conservation
Economic History and History of Economics: Complementary Approaches to Portuguese Economic Development
This chapter focuses on how the problems of economic development were addressed by the Portuguese historiography of the late nineteenth and twentieth centuries. The ensuing discussion benefits from the simultaneous consideration of two historiographical domains that complement each other: economic history and the history of economics. On the one hand, there are the authors and texts of economic history that seek to describe the facts and circumstances related to the functioning and dynamics of economic reality, for a given period or succession of periods, in order to establish evolutionary trends. On the other hand, there are the authors and texts of the history of economics that seek to adopt analytical forms (principles and laws) and doctrinal and programmatic frameworks (visions and ideologies) aimed at providing explanatory meaning to the observed economic changes, phenomena and regularities. A true understanding of the important issues pertaining to Portuguese economic development is to be found, however, in the intersection of these distinct but complementary historiographical perspectives.info:eu-repo/semantics/publishedVersio
Lutzomyia umbratilis, the Main Vector of Leishmania guyanensis, Represents a Novel Species Complex?
BACKGROUND: Lutzomyia umbratilis is an important Leishmania guyanensis vector in South America. Previous studies have suggested differences in the vector competence between L. umbratilis populations situated on opposite banks of the Amazonas and Negro Rivers in the central Amazonian Brazil region, likely indicating a species complex. However, few studies have been performed on these populations and the taxonomic status of L. umbratilis remains unclear. METHODOLOGY/PRINCIPAL FINDINGS: Phylogeographic structure was estimated for six L. umbratilis samples from the central Amazonian region in Brazil by analyzing mtDNA using 1181 bp of the COI gene to assess whether the populations on opposite banks of these rivers consist of incipient or distinct species. The genetic diversity was fairly high and the results revealed two distinct clades ( = lineages) with 1% sequence divergence. Clade I consisted of four samples from the left bank of the Amazonas and Negro Rivers, whereas clade II comprised two samples from the right bank of Negro River. No haplotypes were shared between samples of two clades. Samples within clades exhibited low to moderate genetic differentiation (F(ST) = -0.0390-0.1841), whereas samples between clades exhibited very high differentiation (F(ST) = 0.7100-0.8497) and fixed differences. These lineages have diverged approximately 0.22 Mya in the middle Pleistocene. Demographic expansion was detected for the lineages I and II approximately 30,448 and 15,859 years ago, respectively, in the late Pleistocene. CONCLUSIONS/SIGNIFICANCE: The two genetic lineages may represent an advanced speciation stage suggestive of incipient or distinct species within L. umbratilis. These findings suggest that the Amazonas and Negro Rivers may be acting as effective barriers, thus preventing gene flow between populations on opposite sides. Such findings have important implications for epidemiological studies, especially those related to vector competence and anthropophily, and for vector control strategies. In addition, L. umbratilis represents an interesting example in speciation studies
Scaling up integration: development and results of a participatory assessment of HIV/TB services, South Africa
<p>Abstract</p> <p>Background</p> <p>In South Africa the need to integrate HIV, TB and STI programmes has been recognised at a policy and organisation level; the challenge is now one of translating policies into relevant actions and monitoring implementation to ensure that the anticipated benefits of integration are achieved. In this research, set in public primary care services in Cape Town, South Africa, we set out to determine how middle level managers could be empowered to monitor the implementation of an effective, integrated HIV/TB/STI service.</p> <p>Methods</p> <p>A team of managers and researchers designed an evaluation tool to measure implementation of key components of an integrated HIV/TB/STI package with a focus on integration. They used a comprehensive health systems framework based on conditions for programme effectiveness and then identified and collected tracer indicators. The tool was extensively piloted in two rounds involving 49 clinics in 2003 and 2004 to identify data necessary for effective facility-level management. A subsequent evaluation of 16 clinics (2 per health sub district, 12% of all public primary care facilities) was done in February 2006.</p> <p>Results</p> <p>16 clinics were reviewed and 635 records sampled. Client access to HIV/TB/STI programmes was limited in that 50% of facilities routinely deferred clients. Whilst the physical infrastructure and staff were available, there was problem with capacity in that there was insufficient staff training (for example, only 40% of clinical staff trained in HIV care). Weaknesses were identified in quality of care (for example, only 57% of HIV clients were staged in accordance with protocols) and continuity of care (for example, only 24% of VCT clients diagnosed with HIV were followed up for medical assessment). Facility and programme managers felt that the evaluation tool generated information that was useful to manage the programmes at facility and district level. On the basis of the results facility managers drew up action plans to address three areas of weakness within their own facility.</p> <p>Conclusions</p> <p>This use of the tool which is designed to empower programme and facility managers demonstrates how engaging middle managers is crucial in translating policies into relevant actions.</p
Factors associated with the care of elderly persons with Primary Health Care sensitive conditions
Structure of a lectin from Canavalia gladiata seeds: new structural insights for old molecules
<p>Abstract</p> <p>Background</p> <p>Lectins are mainly described as simple carbohydrate-binding proteins. Previous studies have tried to identify other binding sites, which possible recognize plant hormones, secondary metabolites, and isolated amino acid residues. We report the crystal structure of a lectin isolated from <it>Canavalia gladiata </it>seeds (CGL), describing a new binding pocket, which may be related to pathogen resistance activity in ConA-like lectins; a site where a non-protein amino-acid, α-aminobutyric acid (Abu), is bound.</p> <p>Results</p> <p>The overall structure of native CGL and complexed with α-methyl-mannoside and Abu have been refined at 2.3 Å and 2.31 Å resolution, respectively. Analysis of the electron density maps of the CGL structure shows clearly the presence of Abu, which was confirmed by mass spectrometry.</p> <p>Conclusion</p> <p>The presence of Abu in a plant lectin structure strongly indicates the ability of lectins on carrying secondary metabolites. Comparison of the amino acids composing the site with other legume lectins revealed that this site is conserved, providing an evidence of the biological relevance of this site. This new action of lectins strengthens their role in defense mechanisms in plants.</p
Molecular taxonomy of the two Leishmania vectors Lutzomyia umbratilis and Lutzomyia anduzei (Diptera: Psychodidae) from the Brazilian Amazon
Background: Lutzomyia umbratilis (a probable species complex) is the main vector of Leishmania guyanensis in the northern region of Brazil. Lutzomyia anduzei has been implicated as a secondary vector of this parasite. These species are closely related and exhibit high morphological similarity in the adult stage; therefore, they have been wrongly identified, both in the past and in the present. This shows the need for employing integrated taxonomy. Methods. With the aim of gathering information on the molecular taxonomy and evolutionary relationships of these two vectors, 118 sequences of 663 base pairs (barcode region of the mitochondrial DNA cytochrome oxidase I - COI) were generated from 72 L. umbratilis and 46 L. anduzei individuals captured, respectively, in six and five localities of the Brazilian Amazon. The efficiency of the barcode region to differentiate the L. umbratilis lineages I and II was also evaluated. The data were analyzed using the pairwise genetic distances matrix and the Neighbor-Joining (NJ) tree, both based on the Kimura Two Parameter (K2P) evolutionary model. Results: The analyses resulted in 67 haplotypes: 32 for L. umbratilis and 35 for L. anduzei. The mean intra-specific genetic distance was 0.008 (0.002 to 0.010 for L. umbratilis; 0.008 to 0.014 for L. anduzei), whereas the mean interspecific genetic distance was 0.044 (0.041 to 0.046), supporting the barcoding gap. Between the L. umbratilis lineages I and II, it was 0.009 to 0.010. The NJ tree analysis strongly supported monophyletic clades for both L. umbratilis and L. anduzei, whereas the L. umbratilis lineages I and II formed two poorly supported monophyletic subclades. Conclusions: The barcode region clearly separated the two species and may therefore constitute a valuable tool in the identification of the sand fly vectors of Leishmania in endemic leishmaniasis areas. However, the barcode region had not enough power to separate the two lineages of L. umbratilis, likely reflecting incipient species that have not yet reached the status of distinct species. © 2013 Scarpassa and Alencar; licensee BioMed Central Ltd
Antibacterial properties and healing effects of Melipona scutellaris honey in MRSA-infected wounds of rats
Chimera-like states in modular neural networks
Chimera states, namely the coexistence of coherent and incoherent behavior, were previously analyzed in complex networks. However, they have not been extensively studied in modular networks. Here, we consider a neural network inspired by the connectome of the C. elegans soil worm, organized into six interconnected communities, where neurons obey chaotic bursting dynamics. Neurons are assumed to be connected with electrical synapses within their communities and with chemical synapses across them. As our numerical simulations reveal, the coaction of these two types of coupling can shape the dynamics in such a way that chimera-like states can happen. They consist of a fraction of synchronized neurons which belong to the larger communities, and a fraction of desynchronized neurons which are part of smaller communities. In addition to the Kuramoto order parameter ?, we also employ other measures of coherence, such as the chimera-like ? and metastability ? indices, which quantify the degree of synchronization among communities and along time, respectively. We perform the same analysis for networks that share common features with the C. elegans neural network. Similar results suggest that under certain assumptions, chimera-like states are prominent phenomena in modular networks, and might provide insight for the behavior of more complex modular networks
Recommended from our members
Intermediate predator naïveté and sex-skewed vulnerability predict the impact of an invasive higher predator
The spread of invasive species continues to reduce biodiversity across all regions and habitat types globally. However, invader impact prediction can be nebulous, and approaches often fail to integrate coupled direct and indirect invader effects. Here, we examine the ecological impacts of an invasive higher predator on lower trophic groups, further developing methodologies to more holistically quantify invader impact. We employ functional response (FR, resource use under different densities) and prey switching experiments to examine the trait- and density-mediated impacts of the invasive mosquitofish Gambusia affinis on an endemic intermediate predator Lovenula raynerae (Copepoda). Lovenula raynerae effectively consumed larval mosquitoes, but was naïve to mosquitofish cues, with attack rates and handling times of the intermediate predator unaffected by mosquitofish cue-treated water. Mosquitofish did not switch between male and female prey, consistently displaying a strong preference for female copepods. We thus demonstrate a lack of risk-reduction activity in the presence of invasive fish by L. raynerae and, in turn, high susceptibility of such intermediate trophic groups to invader impact. Further, we show that mosquitofish demonstrate sex-skewed predator selectivity towards intermediate predators of mosquito larvae, which may affect predator population demographics and, perversely, increase disease vector proliferations. We advocate the utility of FRs and prey switching combined to holistically quantify invasive species impact potential on native organisms at multiple trophic levels
- …