481 research outputs found
Survival, extinction and approximation of discrete-time branching random walks
We consider a general discrete-time branching random walk on a countable set
X. We relate local, strong local and global survival with suitable inequalities
involving the first-moment matrix M of the process. In particular we prove
that, while the local behavior is characterized by M, the global behavior
cannot be completely described in terms of properties involving M alone.
Moreover we show that locally surviving branching random walks can be
approximated by sequences of spatially confined and stochastically dominated
branching random walks which eventually survive locally if the (possibly
finite) state space is large enough. An analogous result can be achieved by
approximating a branching random walk by a sequence of multitype contact
processes and allowing a sufficiently large number of particles per site. We
compare these results with the ones obtained in the continuous-time case and we
give some examples and counterexamples.Comment: 32 pages, a few misprints have been correcte
Different proportion of root cutting and shoot pruning influence the growth of citronella plants
Environment concern, sustainable products demand, and natural components
conscious are currently global movement factors. Related to the global movement factors,
citronella grass (Cymbopogon nardus L.) is being widely used in folk medicine, and has insect
repellent activity, fungal and bactericidal action. Its essential oil has high content of citronellal,
citronellol, geraniol. The essential oil is mostly extracted from leaves which turns this plant with
high commercial demand. However, to obtain the best therapeutic quality and productivity of
medicinal plants, which culminates in greater quantity and quality of the active compounds, the
proper management of the crop is fundamental, as several factors can interfere during its growth
and development. Thus, we analyzed the growth of citronella plants submitted to different levels
of shoot and root cuts. Five different proportions of root pruning (0, 25, 50, 75, 100%), after 145
days of seedling planting and four cuttings in the shoots: blunt; a cut at 145 DAP (days after
planting) along with the root cut; a cut at 228 DAP; and cuts at 145 and 228 DAP (two cuts). Four
harvesting for dry matter accumulation and photoassimilate partition data were performed. The
treatment with 100% root cut, but without leaf cut, increased the total dry mass accumulation of
the plant in relation to the other treatments, for the last analysis period, demonstrating a recovery.
Thus, the application of two leaf cuts or no leaf cutting within the 100% root cut treatment for
leaf dry mass accumulation is more effective when compared to the blunt root treatment
Generation and characterization of a recombinant chimeric protein (rCpLi) consisting of B-cell epitopes of a dermonecrotic protein from Loxosceles intermedia spider venom
AbstractA chimeric protein was constructed expressing three epitopes of LiD1, a dermonecrotic toxin from the venom of Loxosceles intermedia spider. This species is responsible for a large number of accidents involving spiders in Brazil. We demonstrated that the chimeric protein (rCpLi) generated is atoxic and that antibodies previously developed in rabbits against synthetic epitopes reactive with rCpLi in ELISA and immunoblot assays. The antibody response in rabbits against the rCpLi was evaluated by ELISA and we have detected an antibody response in all immunized animals. Overlapping peptides covering the amino acid sequence of the rCpLi were synthesized on a cellulose membrane, and their recognition by rabbit anti-rCpLi serum assessed. Three different antigenic regions were identified. The percentage of inhibition of the dermonecrotic, hemorrhagic and edematogenic activities caused by the recombinant protein LiD1r in naïve rabbits was assessed by pre-incubation with anti-rCpLi antibodies. Anti-rCpLi induced good dermonecrotic and hemorrhagic protection. The levels of protection were similar to the antiboides anti-LiD1r. In summary, we have developed a polyepitope recombinant chimeric protein capable of inducing multiple responses of neutralizing antibodies in a rabbit model. This engineered protein may be a promising candidate for therapeutic serum development or vaccination
Hantavirus Pulmonary Syndrome, Central Plateau, Southeastern, and Southern Brazil
This syndrome is an increasing health problem because of human encroachment into habitats of rodent reservoirs
Seed-borne pathogens and electrical conductivity of soybean seeds
Adequate procedures to evaluate seed vigor are important. Regarding the electrical conductivity test (EC), the interference in the test results caused by seed-borne pathogens has not been clarified. This research was carried out to study the influence of Phomopsis sojae (Leh.) and Colletotrichum dematium (Pers. ex Fr.) Grove var. truncata (Schw.) Arx. fungi on EC results. Soybean seeds (Glycine max L.) were inoculated with those fungi using potato, agar and dextrose (PDA) medium with manitol (-1.0 MPa) and incubated for 20 h at 25 °C. The colony diameter, index of mycelial growth, seed water content, occurrence of seed-borne pathogens, physiological potential of the seeds, measured by germination and vigor tests (seed germination index, cold test, accelerated aging and electrical conductivity), and seedling field emergence were determined. The contents of K+, Ca2+, and Mg2+ in the seed and in the soaking solution were also determined. A complete 2 × 4 factorial design with two seed sizes (5.5 and 6.5 mm) and four treatments (control, seeds incubated without fungi, seeds incubated with Phomopsis and seeds incubated with Colletotrichum) were used with eight (5.5 mm large seeds) and six (6.5 mm large seeds) replications. All seeds submitted to PDA medium had their germination reduced in comparison to the control seeds. This reduction was also observed when seed vigor and leached ions were considered. The presence of Phomopsis sojae fungus in soybean seed samples submitted to the EC test may be the cause of misleading results
Access to infertility consultations: what women tell us about it?
The main objective of the present paper is to evaluate the perception of women concerning the barriers and access to infertility consultations. Socio cultural and economic access to infertility consultations is detached and three municipalities of the northwest of Portugal were chosen as an example of a peripheral country. A quantitative/qualitative study was done with 60 women. Three dimensions were evaluated: geographic and structural and functional access; economic access; and sociocultural access. The main barriers were mainly identified in the last two dimensions. The economic access was the less well evaluated by women being the cost of treatment (medication, and concentration of costs in a short period) difficult to bear. This can justify a greater involvement of the Portuguese Government, by developing policies for the reimbursement of part of the costs. Also, some changes in structural and functional access must be done with special regard to the separation of the infertility consultations from the reproductive medicine section. The setting of the teams, with a follow-up by the same team of health professionals is also needed
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