On the Computational Complexity of the Strong Geodetic Recognition Problem

A strong geodetic set of a graph~$G=(V,E)$ is a vertex set~$S \subseteq V(G)$ in which it is possible to cover all the remaining vertices of~$V(G) \setminus S$ by assigning a unique shortest path between each vertex pair of~$S$. In the Strong Geodetic problem (SG) a graph~$G$ and a positive integer~$k$ are given as input and one has to decide whether~$G$ has a strong geodetic set of cardinality at most~$k$. This problem is known to be NP-hard for general graphs. In this work we introduce the Strong Geodetic Recognition problem (SGR), which consists in determining whether even a given vertex set~$S \subseteq V(G)$ is strong geodetic. We demonstrate that this version is NP-complete. We investigate and compare the computational complexity of both decision problems restricted to some graph classes, deriving polynomial-time algorithms, NP-completeness proofs, and initial parameterized complexity results, including an answer to an open question in the literature for the complexity of SG for chordal graphs

Supine sleep and positional sleep apnea after acute ischemic stroke and intracerebral hemorrhage

OBJECTIVE: Obstructive sleep apnea is frequent during the acute phase of stroke, and it is associated with poorer outcomes. A well-established relationship between supine sleep and obstructive sleep apnea severity exists in non-stroke patients. This study investigated the frequency of supine sleep and positional obstructive sleep apnea in patients with ischemic or hemorrhagic stroke. METHODS: Patients who suffered their first acute stroke, either ischemic or hemorrhagic, were subjected to a full polysomnography, including the continuous monitoring of sleep positions, during the first night after symptom onset. Obstructive sleep apnea severity was measured using the apnea-hypopnea index, and the NIHSS measured stroke severity. RESULTS: We prospectively studied 66 stroke patients. The mean age was 57.6±11.5 years, and the mean body mass index was 26.5±4.9. Obstructive sleep apnea (apnea-hypopnea index >5) was present in 78.8% of patients, and the mean apnea-hypopnea index was 29.7±26.6. The majority of subjects (66.7%) spent the entire sleep time in a supine position, and positional obstructive sleep apnea was clearly present in the other 23.1% of cases. A positive correlation was observed between the NIHSS and sleep time in the supine position (r s = 0.5;

Antiproliferative Activity Of Flavonoids From Croton Sphaerogynus Baill. (euphorbiaceae).

Croton sphaerogynus is a shrub from the Atlantic Rain Forest in southeastern Brazil. A lyophilized crude EtOH extract from leaves of C. sphaerogynus, obtained by maceration at room temperature (seven days), was suspended in methanol and partitioned with hexane. The purified MeOH phase was fractionated over Sephadex LH-20 yielding five fractions (F1-F5) containing flavonoids, as characterized by HPLC-DAD and HPLC-MS analyses. The antiproliferative activity of the crude EtOH extract, MeOH and hexane phases, and fractions F1-F5 was evaluated on in vitro cell lines NCI-H460 (nonsmall cell lung), MCF-7 (breast cancer), and U251 (glioma). The MeOH phase showed activity (mean log GI50 0.54) higher than the hexane phase and EtOH extract (mean log GI50 1.13 and 1.19, resp.). F1 exhibited activity against NCI-H460 (nonsmall cell lung) (GI50 1.2 μg/mL), which could be accounted for the presence of flavonoids and/or diterpenes. F4 showed moderate activity (mean log GI50 1.05), while F5 showed weak activity (mean log GI50 1.36). It is suggested that the antiproliferative activity of the crude EtOH extract and MeOH phase is accounted for a synergistic combination of flavonoids and diterpenes.201521280

Zoneamento agroclimático para produção de mudas de morangueiro no Rio Grande do Sul.

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\u3cem\u3eIn Situ\u3c/em\u3e Digestibility of \u3cem\u3eGliricidia sepium\u3c/em\u3e Combined with \u3cem\u3eBrachiaria decumbens\u3c/em\u3e in a Silvopastoral System

Silvopastoral system (SPS) are characterized by a combination of trees, pasture and herbivores animals, in the same physical area, in order to obtain diversified products. A promising legume tree that has been studied and used in SPS in tropical areas is gliricidia [Gliricidia sepium (Jacq.) Steud]. Advantages of gliricidia use in SPS include N inputs via biological fixation, improvement of soil properties, nutrient cycling and also a source of feed to grazing animals (Cubillos-Hinojosa et al., 2011). Gliricidia has high crude protein concentration in its leaves, which complements the usual N-poor diet of ruminants grazing warm-season grasses. The introduction of gliricidia in SPS faces a problem due to the low initial acceptability by cattle, being necessary an adaptation period in order to cattle reach satisfactory intake levels (Carvalho Filho et al., 1997). In general, the quality of the forages can be predicted by accessing their nutritive value, represented by the chemical composition and digestibility of the forage constituents (Van Soest, 1994). The digestibility of dry matter in forages consumed in a SPS can be influenced by the forage species used, by grass/legume combinations, and by the proportion that each forage species takes in the diet of the ruminants. This study evaluated in situ digestibility of gliricidia in increasing levels of inclusion in the diet composed by sabi grass (Brachiaria decumbens, Stapf) in a silvopastoral system

Canopy Height and Its Relationship with Leaf Area Index and Light Interception of Tropical Grasses

Photosynthetic tissues, mainly green leaves, are the major component of forage growth and development. The amount of these tissues in a forage plant is influenced directly by the cutting management, which is based on cutting frequency and stubble height. It is usual to recommend as a management practice to cut (or graze) the forage whenever it reaches a given stubble height. Brougham (1956) stated that, when the forage canopy is intercepting 95% of the photosynthetic active radiation, this is the critical leaf area index (LAI), which means the forage is near its maximum growth rate without shading itself. There is also the optimum LAI, where the forage reaches the maximum point of mass accumulation, indicating time to start grazing or cut. Generally the critical and optimum LAI have close values, but they are not necessarily the same (Brown and Blaser, 1968). This trial evaluated the relationship among canopy height, leaf area index, and light interception in ten different tropical grasses

Hepatitis B virus infection in Haemodialysis Centres from Santa Catarina State, Southern Brazil. Predictive risk factors for infection and molecular epidemiology.

BACKGROUND: Patients under haemodialysis are considered at high risk to acquire hepatitis B virus (HBV) infection. Since few data are reported from Brazil, our aim was to assess the frequency and risk factors for HBV infection in haemodialysis patients from 22 Dialysis Centres from Santa Catarina State, south of Brazil. METHODS: This study includes 813 patients, 149 haemodialysis workers and 772 healthy controls matched by sex and age. Serum samples were assayed for HBV markers and viraemia was detected by nested PCR. HBV was genotyped by partial S gene sequencing. Univariate and multivariate statistical analyses with stepwise logistic regression analysis were carried out to analyse the relationship between HBV infection and the characteristics of patients and their Dialysis Units. RESULTS: Frequency of HBV infection was 10.0%, 2.7% and 2.7% among patients, haemodialysis workers and controls, respectively. Amidst patients, the most frequent HBV genotypes were A (30.6%), D (57.1%) and F (12.2%). Univariate analysis showed association between HBV infection and total time in haemodialysis, type of dialysis equipment, hygiene and sterilization of equipment, number of times reusing the dialysis lines and filters, number of patients per care-worker and current HCV infection. The logistic regression model showed that total time in haemodialysis, number of times of reusing the dialysis lines and filters, and number of patients per worker were significantly related to HBV infection. CONCLUSIONS: Frequency of HBV infection among haemodialysis patients at Santa Catarina state is very high. The most frequent HBV genotypes were A, D and F. The risk for a patient to become HBV positive increase 1.47 times each month of haemodialysis; 1.96 times if the dialysis unit reuses the lines and filters > or = 10 times compared with haemodialysis units which reuse < 10 times; 3.42 times if the number of patients per worker is more than five. Sequence similarity among the HBV S gene from isolates of different patients pointed out to nosocomial transmission

Isolation of Root Endophytic Bacteria in Elephant Grass (\u3cem\u3ePennisetum purpureum\u3c/em\u3e Schum.) Cultivars

Elephant grass (Pennisetum purpureum Schum.) is one of the most productive warm-season grasses. Farmers utilize elephant grass in different forms, such as cut-and-carry operations, grazing, conserved forage (silage, hay), and as an energy source (Lira et al. 2010). Nitrogen (N) is an essential element for plant growth and development and it is usually a limiting factor for forage production in the tropics (Boddey et al. 2004). Biological N fixation (BNF) may occur in warm-season grasses by their association with diazotrophic bacteria. These bacteria colonize different niches in the host plant. Endophytic bacteria form colonies inside the plant tissue whereas epiphytic bacteria colonize plant external surfaces (Compant et al. 2010). Both types of bacteria may benefit host plants (Badri et al. 2009). This study evaluated endophytic diazotrophic bacteria density associated to the roots of different elephant grass cultivars (cvs. ‘Elefante B’, ‘Venezuela’, and ‘Pioneiro’) using two N-free growth media, at different evaluation periods

High-resolution genetic map and QTL analysis of growth-related traits of Hevea brasiliensis cultivated under suboptimal temperature and humidity conditions

Rubber tree (Hevea brasiliensis) cultivation is the main source of natural rubber worldwide and has been extended to areas with suboptimal climates and lengthy drought periods; this transition affects growth and latex production. High-density genetic maps with reliable markers support precise mapping of quantitative trait loci (QTL), which can help reveal the complex genome of the species, provide tools to enhance molecular breeding, and shorten the breeding cycle. In this study, QTL mapping of the stem diameter, tree height, and number of whorls was performed for a full-sibling population derived from a GT1 and RRIM701 cross. A total of 225 simple sequence repeats (SSRs) and 186 single-nucleotide polymorphism (SNP) markers were used to construct a base map with 18 linkage groups and to anchor 671 SNPs from genotyping by sequencing (GBS) to produce a very dense linkage map with small intervals between loci. The final map was composed of 1,079 markers, spanned 3,779.7 cM with an average marker density of 3.5 cM, and showed collinearity between markers from previous studies. Significant variation in phenotypic characteristics was found over a 59-month evaluation period with a total of 38 QTLs being identified through a composite interval mapping method. Linkage group 4 showed the greatest number of QTLs (7), with phenotypic explained values varying from 7.67 to 14.07%. Additionally, we estimated segregation patterns, dominance, and additive effects for each QTL. A total of 53 significant effects for stem diameter were observed, and these effects were mostly related to additivity in the GT1 clone. Associating accurate genome assemblies and genetic maps represents a promising strategy for identifying the genetic basis of phenotypic traits in rubber trees. Then, further research can benefit from the QTLs identified herein, providing a better understanding of the key determinant genes associated with growth of Hevea brasiliensis under limiting water conditions