382 research outputs found

    Combinatorial Assortment Optimization

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    Assortment optimization refers to the problem of designing a slate of products to offer potential customers, such as stocking the shelves in a convenience store. The price of each product is fixed in advance, and a probabilistic choice function describes which product a customer will choose from any given subset. We introduce the combinatorial assortment problem, where each customer may select a bundle of products. We consider a model of consumer choice where the relative value of different bundles is described by a valuation function, while individual customers may differ in their absolute willingness to pay, and study the complexity of the resulting optimization problem. We show that any sub-polynomial approximation to the problem requires exponentially many demand queries when the valuation function is XOS, and that no FPTAS exists even for succinctly-representable submodular valuations. On the positive side, we show how to obtain constant approximations under a "well-priced" condition, where each product's price is sufficiently high. We also provide an exact algorithm for kk-additive valuations, and show how to extend our results to a learning setting where the seller must infer the customers' preferences from their purchasing behavior

    Protein synthesis and degradation gene SNPs related to feed intake, feed efficiency, growth, and ultrasound carcass traits in Nellore cattle.

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    We looked for possible associations of SNPs in genes related to protein turnover, with growth, feed efficiency and carcass traits in feedlot Nellore cattle. Purebred Nellore bulls and steers (N = 290; 378 ± 42 kg body weight, 23 months ± 42 days old) were evaluated for daily feed intake, body weight gain (BWG), gross feed efficiency, feed conversion ratio, partial efficiency of growth, residual feed intake (RFI), ultrasound backfat, rump fat, and ribeye area

    A composição química da goiabeira (Psidium guajava L.)

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    This paper deals with the mineral composition fresh and dry matter production of different organs of 4, 5 old guava (Psidium guajava L.) growth on sandy soil (Savanna) without fertilizer. The data obtained for fresh and dry matter productior are present in table 2 (in Portuguese). The concentration of the elements are presented in table 3 (in Portuguese). Finally, the total amounts of elements absorbed by guava are given in the following table: Element Plant (grams) Fruits (grams) Nitrogen (N) 42,55 20,4 Phosphorus (P) 3,84 2,3 Potassium (K) 52,01 31,3 Calcium (Ca) 47,81 0,2 Magnesium (Mg) 2,

    A Comparative Study of the Outer Membrane Proteome from an Atypical and a Typical Enteropathogenic Escherichia coli

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    This study compared the proteomic profile of outer membrane proteins (OMPs) from one strain of atypical enteropathogenic Escherichia coli (aEPEC) and one of typical EPEC (tEPEC). The OMPs fractions were obtained using sarcosine extraction, and analyzed by one- and two-dimensional gel electrophoresis (1DE and 2DE, respectively). The 1DE OMPs analysis of typical and atypical EPEC evidenced similar patterns; however, the 2DE OMP profile from the aEPEC revealed more protein spots in the 40- to 70-kDa region. 2DE image analysis identified 159 protein spots in both strains whereas 53 protein spots were observed only in tEPEC and 128 were observed only in aEPEC. Remarkably, 41.5% of aEPEC spots showed higher levels of expression compared to tEPEC, some of which with two, others four or even five times more. Twenty-four selected spots were identified using MALDI-TOF mass spectrometry and they corresponded to proteins involved in cell structure and metabolism, as well as in gene regulation. Some of these proteins showed similarity with proteins identified in other E. coli pathotypes. Besides, the differential expression of some proteins in aEPEC may suggest that it could be related to their features that ascertain the adaptation to distinct environments and the worldwide spread distribution of these pathogens

    Evaluation of Nelore, Canchim, Santa Gertrudis, Holstein, Brown Swiss and Caracu as Sire Breeds in Matings with Nelore Cows. Effects on Progeny Growth, Carcass Traits and Crossbred Productivity

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    Over three calf crops, 1096 exposures of 380 Nelore (a Zebu breed) cows to 6 sire breeds Nelore (N), Canchim (C), Santa Gertrudis (G), Holstein (H), Brown Swiss (S), and Caracu (K), resulted in 644 calves weaned for a 63% calving rate. Sire breed effect was significant for birth weight, weaning weight, 13 mo weight and 18 mo weight. HN and SN calves were the heaviest at all weight periods wile CN, GN, and KN calves were the intermediates. Average daily gain from 18 mo to slaughter age was measured in 125 males finished in feed lot and 116 on pasture. A significant breed of sire × finishing system interaction was observed. Under feed lot, HN and SN had higher daily gain and dry matter intake per kg of metabolic weight than the other ones. HN calves showed the worst feed conversion. The average slaughter age was 788 d for feed lot and 989 d for pasture finished steers. Carcass traits were evaluated in 241 slaughtered animals. CN calves had the highest dressing % and edible portion % under both finishing conditions. Crossbred group productivity (calculated as 18 mo weight times the weaning rate %) was greater for locally adapted breeds of sire

    Global Analyses Of Ceratocystis Cacaofunesta Mitochondria: From Genome To Proteome.

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    The ascomycete fungus Ceratocystis cacaofunesta is the causal agent of wilt disease in cacao, which results in significant economic losses in the affected producing areas. Despite the economic importance of the Ceratocystis complex of species, no genomic data are available for any of its members. Given that mitochondria play important roles in fungal virulence and the susceptibility/resistance of fungi to fungicides, we performed the first functional analysis of this organelle in Ceratocystis using integrated omics approaches. The C. cacaofunesta mitochondrial genome (mtDNA) consists of a single, 103,147-bp circular molecule, making this the second largest mtDNA among the Sordariomycetes. Bioinformatics analysis revealed the presence of 15 conserved genes and 37 intronic open reading frames in C. cacaofunesta mtDNA. Here, we predicted the mitochondrial proteome (mtProt) of C. cacaofunesta, which is comprised of 1,124 polypeptides - 52 proteins that are mitochondrially encoded and 1,072 that are nuclearly encoded. Transcriptome analysis revealed 33 probable novel genes. Comparisons among the Gene Ontology results of the predicted mtProt of C. cacaofunesta, Neurospora crassa and Saccharomyces cerevisiae revealed no significant differences. Moreover, C. cacaofunesta mitochondria were isolated, and the mtProt was subjected to mass spectrometric analysis. The experimental proteome validated 27% of the predicted mtProt. Our results confirmed the existence of 110 hypothetical proteins and 7 novel proteins of which 83 and 1, respectively, had putative mitochondrial localization. The present study provides the first partial genomic analysis of a species of the Ceratocystis genus and the first predicted mitochondrial protein inventory of a phytopathogenic fungus. In addition to the known mitochondrial role in pathogenicity, our results demonstrated that the global function analysis of this organelle is similar in pathogenic and non-pathogenic fungi, suggesting that its relevance in the lifestyle of these organisms should be based on a small number of specific proteins and/or with respect to differential gene regulation. In this regard, particular interest should be directed towards mitochondrial proteins with unknown function and the novel protein that might be specific to this species. Further functional characterization of these proteins could enhance our understanding of the role of mitochondria in phytopathogenicity.149

    Melatonin reduces apoptotic cells, SOD2 and HSPB1 and improves the in vitro production and quality of bovine blastocysts.

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