910 resultados para native fragments
Resumo:
Ceramic vessels and milling stones are important components of the archaeological record in several Nuraghi from the Pranemuru Plateau (Sardinia). To obtain information on the possible uses of the milling stones and the content vessels is of great interest to understand the economical activities carried out in these sites by these populations. One of the approaches to obtain information on the plant uses was the phytolith analyses of the sediment adhered both to the surface of the milling stones and to the surface of the vessel content. In total we analyzed eleven archaeological samples and two control samples collected from five different Nuraghi in the Pranemuru Plateau (Nuoro Province, Sardinia). The Nuraghi were located in an area of 10 km radius from nuraghe Arrubiu and were chronologically ascribed to the Bronze Age and one site -Pranu Illixi- to the Iron Age.
Resumo:
BACKGROUND: Plasmodium falciparum MSP2 is a blood stage protein that is associated with protection against malaria. It was shown that the MSP2 dimorphic (D) and constant (C) regions were well recognized by immune human antibodies, and were characterized by major conserved epitopes in different endemic areas and age groups. These Abs recognized merozoite-derived proteins in WB and IFA. Here, the goal was to determine in mice the immunogenicity of the two allelic MSP2 D and C domains formulated with different adjuvants, for their possible use in future clinical studies. METHOD: Female A/J, C3H, and ICR mice were immunized subcutaneously 3 times at 3-week interval with a mixture of allelic and conserved MSP2 long synthetic peptides formulated with different adjuvants. One week after the third injection, sera from each group were obtained and stored at -20°C for subsequent testing. RESULTS: Both domains of the two MSP2 families are immunogenic and the fine specificity and intensity of the Ab responses are dependent on mouse strains and adjuvants. The major epitopes were restricted to the 20-mer peptide sequences comprising the last 8aa of D and first 12aa of C of the two allelic families and the first 20aa of the C region, this for most strains and adjuvants. Strong immune responses were associated with GLA-SE adjuvant and its combination with other TLR agonists (CpG or GDQ) compared to alhydrogel and Montanide. Further, the elicited Abs were also capable of recognizing Plasmodium-derived MSP2 and inhibiting parasite growth in ADCI. CONCLUSION: The data provide a valuable opportunity to evaluate in mice different adjuvant and antigen formulations of a candidate vaccine containing both MSP2 D and C fragments. The formulations with GLA-SE seem to be a promising option to be compared with the alhydrogel one in human clinical trials.
Resumo:
The profound crisis that has affected the Spanish economy since mid - 2008 has been characterized by significant job losses and a marked rise in the country´s unemployment rate. However, unemployment has had a differential impact on different population groups. Compared to native, immigrant workers have experienced higher rates of job loss. Against this backdrop, this paper examines the differences between immigrants and natives (distinguished by gender) in terms of their probability of suffering job loss in the downturn of late 2008 and 2009. Our results indicate that the higher rate of job loss among female immigrant workers can be fully explained by their lower endowment of human capital. By contrast, human capital endowment and over-representation in certain occupations, sectors and regions in which the crisis had greatest impact do not appear to be the only reason for the penalty suffered by immigrant males in terms of their chances of losing their job in the downturn.
Resumo:
This study examines health care utilization of immigrants relative to the native-born populations aged 50 years and older in eleven European countries. Methods. We analyzed data from the Survey of Health Aging and Retirement in Europe (SHARE) from 2004 for a sample of 27,444 individuals in 11 European countries. Negative Binomial regression was conducted to examine the difference in number of doctor visits, visits to General Practitioners (GPs), and hospital stays between immigrants and the native-born individuals. Results: We find evidence those immigrants above age 50 use health services on average more than the native-born populations with the same characteristics. Our models show immigrants have between 6% and 27% more expected visits to the doctor, GP or hospital stays when compared to native-born populations in a number of European countries. Discussion: Elderly immigrant populations might be using health services more intensively due to cultural reasons.
Resumo:
Several bioaffinity assays are based on the detection of an analyte which is bound on a solid substrate via biochemical interaction. These so called solid phase assays are based on the adhesion of the primary binding partner on a solid surface, which then binds the analyte to be detected. In this thesis work a novel solid phase based assay technology, known as spot technology, was developed. The spot technology is based on combination of high-capacity solid phases, concentrated in a spot format, utilising modified streptavidin molecules and recombinant antibody fragments. The reduction of the solid phase binding surface to a size of a spot enabled denser binding of the target molecules, providing improved signal intensities and signal-to-background ratio when applied in different solid phase immunoassays. Streptavidin-biotin interactions are commonly utilised in numerous different bioaffinity assays and the ultimate nature of streptavidin to bind biotin is among the strongest non-covalent interaction reported between two biomolecules. In this study native core streptavidin was chemically modified to provide polymerised streptavidin molecules with altered adsorption properties. These streptavidin conjugates, when coated onto polystyrene surface, provided enhanced biotin binding capacity and surface stability when compared to a reference coating constructed with native streptavidin. Furthermore, the combination of chemically modified streptavidin, sitespecifically biotinylated antibody fragments and the spot coating technology provided highly dense solid phase coating with improved binding properties. The performance of the spot assay technology was further demonstrated in different immunoassay configurations. Human thyroid stimulating hormone (TSH) and human cardiac troponin I (cTnI) were used as model analytes to show the applicability of the highly sensitive spot-based solid-phase immunoassay for detection of very low levels of analytes. It was demonstrated that the spot technology provided an assay concept with enhanced sensitivity and short turn-around times, characteristics that are highly suitable for point-of-care applications.
Resumo:
We experimentally examined the predator-prey relationships between juvenile spotted sorubim Pseudoplastystoma corruscans and young-of-the-year invasive and native fish species of the Paraná River basin, Brazil. Three invasive (peacock bass Cichla piquiti, Nile tilapia Oreochromis niloticus, and channel catfish Ictalurus punctatus) and two native (yellowtail tetra Astyanax altiparanae and streaked prochilod Prochilodus lineatus) fish species were offered as prey to P. corruscans in 300 L aquaria with three habitat complexity treatments (0%, 50% and 100% structure-covered). Prey survival was variable through time and among species (C. piquiti < O. niloticus < A. altiparanae < P. lineatus < I. punctatus), depending largely on species-specific prey behavior but also on prey size and morphological defenses. Habitat complexity did not directly affect P. corruscans piscivory but some prey species changed their microhabitat use and shoaling behavior among habitat treatments in predator’s presence. Pseudoplatystoma corruscans preyed preferentially on smaller individuals of those invasive species with weak morphological defensive features that persisted in a non-shoaling behavior. Overall, our results contrast with those in a companion experiment using a diurnal predator, suggesting that nocturnal piscivores preferentially prey on different (rather diurnal) fish species and are less affected by habitat complexity. Our findings suggest that recovering the native populations of P. corruscans might help controling some fish species introduced to the Paraná River basin, particularly C. piquiti and O. niloticus, whose parental care is expected to be weak or null at night
Resumo:
The Argentine ant, Linepithema humile, is a world-wide invasive ant species. Its presence has a strong negative impact on ant diversity. The present study attempts to highlight the reasons for the coexistence of this highly dominant species with Plagiolepis pygmaea, the only native ant species that has proved able to resist the invasion in a natural ecosystem in the north-east of the Iberian Peninsula. To quantify the aggressiveness level of both species we performed aggressiveness tests on workers in different areas: a) Argentine ant workers from areas with P. pygmaea, b) Argentine ant workers from areas without P. pygmaea, c) P. pygmaea from a non-invaded area and d) P. pygmaea from an invaded area. We also confronted Argentine ant workers with P. pallidula and T. nigerrimum. These aggressiveness tests showed that the coexistence of these two species of ants was not due to a habituation process, since the aggressiveness level observed between the four kinds of confrontations were fairly similar. We also found a lack of aggressiveness between Argentine ant workers and P. pygmaea, and highly submissive behavior in the latter when confronted with the invader. The peaceful character of P. pygmaea together with its markedly submissive behavior may be the main factors behind the coexistence of these species in the study area
Resumo:
This article carries out an empirical examination of the origin of the differences between immigrant and native-born wage structures in the Spanish labour market. Especial attention is given in the analysis to the role played by occupational and workplace segregation of immigrants. Legal immigrants from developing countries exhibit lower mean wages and a more compressed wage structure than native-born workers. By contrast, immigrants from developed countries display higher mean wages and a more dispersed wage structure. The main empirical finding is that the disparities in the wage distributions for the native-born and both groups of immigrants are largely explained by their different observed characteristics, with a particularly important influence in this context of workplace and, particularly, occupational segregation.
Resumo:
This study is focused on the dominance exerted by the invasive Argentine ant over native ants in a coastal Mediterranean area. Theimpact of this invasive ant on native ant assemblages and its consequences on total ant biomass and on the intensity of habitat explorationwere evaluated. Foraging ants were observed and their trajectories recorded during 5-minute periods in two study zones, one invaded andthe other non-invaded. Ant species detected, ant worker abundance, ant biomass and the intensity of soil surface searching done by antswere compared between the two zones. The Argentine ant invasion provoked a drastic reduction of the ant species richness. Apparentlyonly one native ant species is able to coexist with the Argentine ant, the cryptic Plagiolepis pygmaea. Ant worker abundance was also modified after the invasion: the number of Argentine ant workers detected, which represented 92% of the invaded zone, was two times higher than the number of native ant workers detected in the non-invaded zone. The total ant biomass was inversely affected, becoming four times lower in the invaded zone highly dominated by Linepithema humile. The higher number of Argentine ant workers and their fast tempo of activity implied an alteration of the intensity of soil surface searching: scanning by the Argentine ants in the invaded zone was higher than that done by the native ants in the non-invaded zone, and the estimated time for a complete soil surface scan was 64 minutes in the invaded zone and 108 minutes in the non-invaded zone. Consequently, resources will be discovered faster by ants in the invaded zone than in the non-invaded zone. The increase of the mean temperature and the decrease of the relative humidity from May to August reduced the ant activity in the two study zones but this reduction was greater in the invaded zone
Resumo:
Successful plant invaders may have specific morphological and physiological traits that promote invasion in a new habitat. The Evolution of Increased Competitive Ability (EICA) hypothesis predicts that plants released from natural enemies in the introduced habitats are more competitive and perform better than plants from the native populations. An increased phenotypic plasticity may also favour invasion because it allows plants to function under a wider range of environments. In this study we used Senecio pterophorus (Asteraceae) to test whether introduced plant populations are 1)more competitive and 2) more plastic compared with the native populations. We conducted a common garden experiment using plants from the native range (South Africa, Eastern Cape), an expanded range (South Africa, Western Cape) and two introduced ranges (Australia and Europe) under different conditions of water availability. Contrary to the EICA and the increased plasticity hypotheses, plants from the invasive and expanded populations grew less and responded less to watering than those from their native range. These results may be caused by a depleted competition as well as the presence of genetic bottlenecks in the newly invaded areas.
Resumo:
Brazil is one of the largest producers and consumers of charcoal in the world. About 50% of its charcoal comes from native forests, with a large part coming from unsustainable operations. The anatomic identification of charcoal is subjective; an instrumental technique would facilitate the monitoring of forests. This study aimed to verify the feasibility of using medium and near infrared reflectance spectroscopy to discriminate native (ipê) from plantation charcoals (eucalyptus). Principal Components Analysis, followed by Discriminant Factorial Analysis formed two different groups indicated by Mahalanobis distances of 40.6 and 80.3 for near and mid infrared, respectively. Validation of the model showed 100% efficacy.