Showing papers by "University of Costa Rica published in 2004"
TL;DR: This study assembles a geographic information system (GIS) to relate the 2000 census population with an inventory of health facilities (supply) and assesses the equity in access to health care by Costa Ricans and the impact on it by the ongoing reform of the health sector.
314 citations
TL;DR: This study relates parenting of 3-month-old children to children's self-recognition and self-regulation at 18 to 20 months and results are discussed with respect to their implications for culturally informed developmental pathways.
Abstract: This study relates parenting of 3-month-old children to children's self-recognition and self-regulation at 18 to 20 months. As hypothesized, observational data revealed differences in the sociocultural orientations of the 3 cultural samples' parenting styles and in toddlers' development of self-recognition and self-regulation. Children of Cameroonian Nso farmers who experience a proximal parenting style develop self-regulation earlier, children of Greek urban middle-class families who experience a distal parenting style develop self-recognition earlier, and children of Costa Rican middle-class families who experience aspects of both distal and proximal parenting styles fall between the other 2 groups on both self-regulation and self-recognition. Results are discussed with respect to their implications for culturally informed developmental pathways.
288 citations
TL;DR: Axioms for non-unital spectral triples, extending those introduced in the unital case by Connes, are proposed in this paper, and for the sake of their importance in noncommutative quantum field theory, the spaces R2N endowed with Moyal products are intensively investigated.
Abstract: Axioms for nonunital spectral triples, extending those introduced in the unital case by Connes, are proposed. As a guide, and for the sake of their importance in noncommutative quantum field theory, the spaces R2N endowed with Moyal products are intensively investigated. Some physical applications, such as the construction of noncommutative Wick monomials and the computation of the Connes–Lott functional action, are given for these noncommutative hyperplanes.
275 citations
TL;DR: In this paper, the authors derived the power behavior of light-front Fock-state hadronic wavefunctions for hard scattering in the large-r region of the AdS space from the conformal isometries which determine the scaling of string states as we approach the boundary from the interior of AdS. The nonperturbative scaling results were obtained for spin-zero and spin-1/2 hadrons and extended to include the orbital angular momentum dependence of the constituents in the Fockexpansion in the light-cone.
224 citations
TL;DR: Genomic libraries constructed from microbial DNA isolated from insect intestinal tracts from the orders Isoptera and Lepidoptera were screened for genes that encode proteins with xylanase activity and several novel xylan enzyme enzymes with unusual primary sequences and novel domains of unknown function were discovered.
Abstract: Recombinant DNA technologies enable the direct isolation and expression of novel genes from biotopes containing complex consortia of uncultured microorganisms. In this study, genomic libraries were constructed from microbial DNA isolated from insect intestinal tracts from the orders Isoptera (termites) and Lepidoptera (moths). Using a targeted functional assay, these environmental DNA libraries were screened for genes that encode proteins with xylanase activity. Several novel xylanase enzymes with unusual primary sequences and novel domains of unknown function were discovered. Phylogenetic analysis demonstrated remarkable distance between the sequences of these enzymes and other known xylanases. Biochemical analysis confirmed that these enzymes are true xylanases, which catalyze the hydrolysis of a variety of substituted β-1,4-linked xylose oligomeric and polymeric substrates and produce unique hydrolysis products. From detailed polyacrylamide carbohydrate electrophoresis analysis of substrate cleavage patterns, the xylan polymer binding sites of these enzymes are proposed.
173 citations
TL;DR: A significant positive correlation between G II species richness and plant species richness in both deciduous and riparian habitats is found, suggesting that radiation of GII species may be associated with plant species species richness.
Abstract: Summary 1 We tested four hypotheses concerning the variation in species richness of gall-inducing insects (GII) in plant communities. We sampled deciduous and riparian habitats in a tropical dry forest at Chamela-Cuixmala Biosphere Reserve in western Mexico, that differ in phenology and moisture availability. 2 GII species richness might be expected to increase with the richness of host plant species, with life-form complexity of host plants (trees to shrubs, herbs and climbers), with host age or with host plant density. 3 We found 172 plant species, of which more were present in deciduous than in riparian habitats, but 34 (19.8%) occurred in both. A different GII species colonized each of 39 host species. Most GII species (69.2%) were gall midges (Cecidomyiidae). 4 We found a significant positive correlation between GII species richness and plant species richness in both deciduous and riparian habitats, suggesting that radiation of GII species may be associated with plant species richness. 5 Most of the GII species occurred on trees or shrubs rather than herbs or climbers, consistent with structural complexity providing more colonization sites. 6 The frequency of GII was greater on saplings, which may have more undifferentiated meristems susceptible to gall induction. 7 Both the frequency and intensity of damage by galls were greater in deciduous than riparian habitats, indicating a preference of GII species for plants in the more xeric habitat. 8 The frequency of GII increased with host plant density in only 18 (46.2%) of GII species. 9 Richness of GII depends on all proposed factors, although density is often the least important. The effects of host richness and host age are similar to those seen in many specialist folivorous insects, although the unique association of a single insect with a single host is only seen for GII.
167 citations
TL;DR: It is proposed that perceived importance is the best proximal predictor of contact's reduction of prejudice and is distinct from established quantity and quality indicators.
Abstract: Furthering G. W. Allport's (1954) contentions for optimal contact, the authors introduce a new construct: the perceived importance of contact. They propose that perceived importance is the best proximal predictor
of contact's reduction of prejudice. If individuals have opportunities for contact at work or in the neighborhood, their chances to have intergroup acquaintances and friends increase. Intergroup contact among acquaintances and friends can be perceived as more or less important, which in turn determines intergroup evaluations. A 1st study shows that the new measure of perceived importance is indeed distinct from established quantity and quality indicators. The results are cross-validated in a 2nd study that also sheds light on the meaning of importance. In 3rd and 4th studies, structural equation analyses and a meta-analysis support the hypotheses.
154 citations
TL;DR: One in every 3 patients admitted to the PICUs requires ventilatory support, and survival of unselected infants and children receiving MV for more than 12 h was 85%.
Abstract: To describe the daily practice of mechanical ventilation (MV), and secondarily, its outcome in pediatric intensive care units (PICUs) Prospective cohort of infants and children who received MV for at least 12 h Thirty-six medical surgical PICUs All consecutive patients admitted to the PICUs during 2-month period Of the 1893 patients admitted, 659 (35%) received MV for a median time of 4 days (25th percentile, 75%: 2, 6) Median of age was 13 months (25th percentile, 75%: 5, 48) Common indications for MV were acute respiratory failure (ARF) in 72% of the patients, altered mental status in 14% of the patients, and ARF on chronic pulmonary disease in 10% of the patients Median length of stay in the PICUs was 8 days (25th percentile, 75%: 5, 13) Overall mortality rate in the PICUs was 15% (confidence interval 95%: 13–18) for the entire population, 50% (95% CI: 25–74) in patients who received MV because of acute respiratory distress syndrome, 24% (95% CI: 16–35) in patients who received MV for altered mental status and 16% (95% CI: 9–29) in patients who received MV for ARF on chronic pulmonary disease One in every 3 patients admitted to the PICUs requires ventilatory support The ARF was the most common reason for MV, and survival of unselected infants and children receiving MV for more than 12 h was 85%
138 citations
TL;DR: In this paper, the authors present plate tectonic reconstructions of the southern Central American Volcanic Arc (CAVA) reveal that the inception of Cocos Ridge subduction began no earlier than 3 Ma, and possibly as late as 2 Ma.
126 citations
TL;DR: In this article, the authors analyzed culturally formed parenting styles during infancy, as related to the sociocultural orientations of independence and interdependence, and found that two styles of parenting (distal and proximal) can express parenting priorities in particular ecocultural environments.
Abstract: Objective. This study analyzes culturally formed parenting styles during infancy, as related to the sociocultural orientations of independence and interdependence. Design. Free-play situations between mothers and 3-month-old infants were videotaped in 5 cultural communities that differ according to their sociocultural orientations: cultural communities in West Africa (N = 26), Gujarat in India (N = 39), Costa Rica (N = 21), Greece (N = 51), and Germany (N = 56). The videotapes were analyzed using coding systems that operationalize the component model of parenting with a focus on 4 parenting systems, including body contact, body stimulation, object stimulation, and face-to-face contact. Results. 2 styles of parenting (distal and proximal) can be related to the sociocultural orientations of independence and interdependence. It is apparent that they express parenting priorities in particular ecocultural environments. Conclusions. Infants participate, from birth on, in sociocultural activities that are commit...
118 citations
TL;DR: In this paper, the authors present a general algebraic-combinatorial proof of the cancellation-free formula for antipodes, in its original diagrammatic form, for Hopf algebras.
Abstract: This manuscript stands at the interface between combinatorial Hopf algebra theory and renormalization theory. Its plan is as follows: Section 1 is the introduction, and contains as well an elementary invitation to the subject. The rest of part I, comprising Sections 2-6, is devoted to the basics of Hopf algebra theory and examples, in ascending level of complexity. Part II turns around the all-important Faa di Bruno Hopf algebra. Section 7 contains a first, direct approach to it. Section 8 gives applications of the Faa di Bruno algebra to quantum field theory and Lagrange reversion. Section 9 rederives the related Connes-Moscovici algebras. In Part III we turn to the Connes-Kreimer Hopf algebras of Feynman graphs and, more generally, to incidence bialgebras. In Section10 we describe the first. Then in Section11 we give a simple derivation of (the properly combinatorial part of) Zimmermann's cancellation-free method, in its original diagrammatic form. In Section 12 general incidence algebras are introduced, and the Faa di Bruno bialgebras are described as incidence bialgebras. In Section 13, deeper lore on Rota's incidence algebras allows us to reinterpret Connes-Kreimer algebras in terms of distributive lattices. Next, the general algebraic-combinatorial proof of the cancellation-free formula for antipodes is ascertained; this is the heart of the paper. The structure results for commutative Hopf algebras are found in Sections 14 and 15. An outlook section very briefly reviews the coalgebraic aspects of quantization and the Rota-Baxter map in renormalization.
TL;DR: The integrity of the cag pathogenicity island is determined by using specific flanking and internally anchored PCR primers to know the biogeographical distribution of strains carrying fully integral cag-PAI with proinflammatory behavior in vivo to contribute to the understanding of the pathogen-host interaction in health and disease.
Abstract: The cag pathogenicity island (cag-PAI) is one of the major virulence determinants of Helicobacter pylori. The chromosomal integrity of this island or the lack thereof is speculated to play an important role in the progress of the gastroduodenal pathology caused by H. pylori. We determined the integrity of the cag-PAI by using specific flanking and internally anchored PCR primers to know the biogeographical distribution of strains carrying fully integral cag-PAI with proinflammatory behavior in vivo. Genotypes based on eight selected loci were studied in 335 isolates obtained from eight different geographic regions. The cag-PAI appeared to be disrupted in the majority of patient isolates throughout the world. Conservation of cag-PAI was highest in Japanese isolates (57.1%). However, only 18.6% of the Peruvian and 12% of the Indian isolates carried an intact cag-PAI. The integrity of cag-PAI in European and African strains was minimal. All 10 strains from Costa Rica had rearrangements. Overall, a majority of the strains of East Asian ancestry were found to have intact cag-PAI compared to strains of other descent. We also found that the cagE and cagT genes were less often rearranged (18%) than the cagA gene (27%). We attempted to relate cag-PAI rearrangement patterns to disease outcome. Deletion frequencies of cagA, cagE, and cagT genes were higher in benign cases than in isolates from severe ulcers and gastric cancer. Conversely, the cagA promoter and the left end of the cag-PAI were frequently rearranged or deleted in isolates linked to severe pathology. Analysis of the cag-PAI genotypes with a different biogeoclimatic history will contribute to our understanding of the pathogen-host interaction in health and disease.
TL;DR: The data strongly suggest that the adherence mechanism of brucellae to epithelial cells and macrophages is mediated by cellular receptors containing sialic acid and sulphated residues, which may represent a mechanism for spread within the host tissues.
Abstract: The basis for the interaction of Brucella species with the surface of epithelial cells before migration in the host within polymorphonuclear leucocytes is largely unknown. Here, we studied the ability of Brucella abortus and Brucella melitensis to adhere to cultured epithelial (HeLa and HEp-2) cells and THP-1-derived macrophages, and to bind extracellular matrix proteins (ECM). The brucellae adhered to epithelial cells forming localized bacterial microcolonies on the cell surface, and this process was inhibited significantly by pretreatment of epithelial cells with neuraminidase and sodium periodate and by preincubation of the bacteria with heparan sulphate and N-acetylneuraminic acid. Trypsinization of epithelial cells yielded increased adherence, suggesting unmasking of target sites on host cells. Notably, the brucellae also adhered to cultured THP-1 cells, and this event was greatly reduced upon removal of sialic acid residues from these cells with neuraminidase. B. abortus bound in a dose-dependent manner to immobilized fibronectin and vitronectin and, to a lesser extent, to chondroitin sulphate, collagen and laminin. In sum, our data strongly suggest that the adherence mechanism of brucellae to epithelial cells and macrophages is mediated by cellular receptors containing sialic acid and sulphated residues. The recognition of ECM (fibronectin and vitronectin) by the brucellae may represent a mechanism for spread within the host tissues. These are novel findings that offer new insights into understanding the interplay between Brucella and host cells.
TL;DR: Batimastat exerted a significant inhibition of in vitro coagulant and in vivo defibrinogenating effects of venom, evidencing that metalloproteinases play a key role in the coagULopathy characteristic of B. asper envenomation and may become a therapeutic alternative in this pathology.
TL;DR: A series of anatomical and pharmacological studies demonstrated that both sPLA2s produce activation of dorsal horn astrocytes and microglia that is more prominent ipsilateral to the site of injection, which may have general implications for the understanding of inflammatory pain.
Abstract: Snakebites constitute a serious public health problem in Central and South America, where species of the lancehead pit vipers (genus Bothrops) cause the majority of accidents. Bothrops envenomations are very painful, and this effect is not neutralized by antivenom treatment. Two variants of secretory phospholipases A2 (sPLA2), corresponding to Asp49 and Lys49 PLA2s, have been isolated from Bothrops asper venom. These sPLA2s induce hyperalgesia in rats following subcutaneous injection. However, venom in natural Bothrops bites is frequently delivered intramuscularly, thereby potentially reaching peripheral nerve bundles. Thus, the present series of experiments tested whether these sPLA2s could exert pain-enhancing effects following administration around healthy sciatic nerve. Both were found to produce mechanical allodynia ipsilateral to the injection site; no thermal hyperalgesia was observed. As no prior study has examined potential spinal mechanisms underlying sPLA2 actions, a series of anatomical and pharmacological studies were performed. These demonstrated that both sPLA2s produce activation of dorsal horn astrocytes and microglia that is more prominent ipsilateral to the site of injection. As proinflammatory cytokines and nitric oxide have each been previously implicated in spinally mediated pain facilitation, the effect of pharmacological blockade of these substances was tested. The results demonstrate that mechanical allodynia induced by both sPLA2s is blocked by interleukin-1 receptor antagonist, anti-rat interleukin-6 neutralizing antibody, the anti-inflammatory cytokine interleukin-10, and a nitric oxide synthesis inhibitor (L-NAME). As a variety of immune cells also produce and release sPLA2s during inflammatory states, the data may have general implications for the understanding of inflammatory pain.
TL;DR: Based on the distribution of live coral cover and species richness, three conservation units were identified as priority, with the southern and northernmost sides of the marine protected area as the most significant.
Abstract: SUMMARY Sampling scale and lack of attention to taxa other than scleractinian corals have limited the capacity to protect coral reefs and coral communities in Pacific Panama. The distribution of coral habitats (live coral cover) and their species richness in the largest marine protected area of Panama, the Coiba National Park (270125 ha), is described using quadrat transects and manta tows. The species richness of scleractinian corals and octocorals was lower in coral reefs than in coral communities, and a close relationship between richness and live coral cover was observed only in coral communities. The distribution of high live coral cover in coral communities overlapped with areas of high coral species richness. Average live coral cover in communities was 64%, comparedto28%inreefs,whereasalgaecoverwas30%and 49%, respectively. Twenty-two coral and 34 octocoral species were observed, many only now detected in Panama as endemic or new species. Analysis of satellite imagery showed 80% of terrestrial habitats were mostly primary forest, and coral reefs and coral communities covered 1700 ha, about 2% of marine habitats. Shallow marine environments (<20 m) had up to 60% calcareous red algae cover (rhodolite beds). Basedonthedistributionoflivecoralcoverandspecies richness, three conservation units were identified as priority, with the southern and northernmost sides of the marine protected area as the most significant. These three areas encompass most of the rare and endemic species or populations, as well as species previously regarded as endangered.
TL;DR: Analysis of production parameters indicate that acid pH treatments and caprylic acid precipitations, which have been validated for the manufacture of some human IgG products, appear to provide the best potential for viral inactivation of antivenoms.
TL;DR: The impact of the reforma of the sector de la salud in Costa Rica in 1995 on the mortalidad de ninos and adultos and the equidad in the acceso a los servicios de salud was analyzed in this paper.
Abstract: OBJETIVO: Valorar el impacto de la reforma del sector de la salud iniciada en Costa Rica en 1995 sobre la mortalidad de ninos y adultos y la equidad en el acceso a los servicios de salud. METODOS: La reforma del sector de la salud se inicio en Costa Rica en 1995 en algunos distritos, pero en otros su adopcion fue posterior. Esto permitio efectuar un analisis de series temporales, usando un diseno cuasiexperimental con observaciones anuales de 1985 a 2001 en cada uno de los 420 distritos que tenia Costa Rica en 1984. Las series temporales se dividieron en tres periodos que permitieron agrupar a los distritos en tres categorias (grupo pionero, intermedio y tardio) segun el momento en que iniciaron el proceso de reforma: 1995-1996; 1997-2000; 2001 o despues, respectivamente. Las series incluyeron datos de defuncion desagregadas por sexo, grupos de edad y tres grandes grupos de causas de muerte (enfermedades transmisibles, de origen social, o cronicas); estimaciones de poblacion por edad y sexo; dos variables que miden la intervencion (si el distrito ha adoptado o no la reforma y, en caso de que si, el numero de anos desde que adopto la reforma); y ocho variables para controlar efectos de confusion. Los datos se obtuvieron de los registros de defunciones y nacimientos, censos de poblacion y estimaciones demograficas. Se usaron modelos de regresion multiple de Poisson con efectos fijos para estimar el impacto de la reforma en la mortalidad. Tambien se valoro el acceso de la poblacion a los servicios de salud en el primer nivel de atencion antes y despues de la reforma. El indicador de acceso utilizado fue el porcentaje de personas que vivian a menos de 4 km de distancia de un servicio que ofreciera consultas medicas. RESULTADOS: Segun lo estimado por los modelos de regresion, la adopcion de la reforma redujo significativamente la mortalidad de los ninos en 8% y la de los adultos en 2%. El efecto fue de 14% en la mortalidad de adultos debida a enfermedades transmisibles o desencadenadas por procesos infecciosos, nulo en la debida a causas sociales y similar al total (2%) en la mortalidad debida a enfermedades cronicas. Se estima que la reforma salvo aproximadamente 120 vidas de ninos y 350 vidas de adultos en el ano 2001 unicamente. La reforma se puso en marcha primero en las zonas menos densamente pobladas y de menor desarrollo socioeconomico. Como resultado, la brecha en la equidad del acceso a los servicios de salud en el primer nivel de atencion se redujo significativamente. El porcentaje de personas sin acceso equitativo a los servicios de salud del primer nivel de atencion se redujo en 15% entre 1994 y 2000 en las areas que adoptaron la reforma en 1995-1996, mientras que en las areas que no habian adoptado la reforma en 2000, la reduccion fue solo de 3%. CONCLUSION: La reforma redujo significativamente la mortalidad en Costa Rica y puso fin a una decada de estancamiento en algunos indicadores, como la esperanza de vida. El efecto de la reforma se produjo probablemente gracias a su focalizacion en las regiones menos desarrolladas del pais, lo cual dio lugar a un mejoramiento en la equidad de acceso al primer nivel de atencion medica.
TL;DR: Together, these experiments have established optimized parameters for propagation and growth of C. cujete plantlets in a sterile controlled environment for biochemical characterization and production of high-quality medicinal products.
Abstract: Crescentia cujete L. is a widely distributed medicinal tree with a diverse range of phytochemicals used as medicinal compounds. Seedlings of wild-harvested C. cujete were established in vitro and used as the starting material for the establishment of axenic cultures. Shoots were proliferated from nodal segments and were maintained over a period of more than 2 years by sequential subculture on a medium containing 1.0 µmol l−1 kinetin. De novo regeneration was induced on petiole sections cultured onto a medium containing thidiazuron in combination with 2,4-dichlorophenoxyacetic acid. Axenic cultures were also used to test the efficiency of three different cultivation systems for production of biomass of C. cujete. Growth of plantlets in a temporary immersion bioreactor resulted in significant increases in biomass, leaf number, shoot height and transplant efficiency. Plantlets grown in the bioreactors were acclimatized under greenhouse conditions. Together, these experiments have established optimized parameters for propagation and growth of C. cujete plantlets in a sterile controlled environment for biochemical characterization and production of high-quality medicinal products.
TL;DR: Spinal proinflammatory cytokines, nitric oxide, and prostanoids each appear to be involved in the pain‐enhancing effects of these sPLA2s, providing the first evidence of spinal mediators involved in pain facilitation induced by subcutaneous venoms.
Abstract: Snakebites are a relevant public health problem in Central and South America Snake bite envenomations cause intense pain, not relieved by anti-venom The fangs of many species are short, causing subcutaneous injection Fangs of larger species inflict subcutaneous or intramuscular envenomation To understand pain induced by subcutaneous venom, this study examined spinal mechanisms involved in pain-enhancing effects of subcutaneous Lys49 and Asp49 secretory phospholipase-A2 (sPLA2), two components of Bothrops asper snake venom showing highly different enzymatic activities Unilateral intraplantar sPLA2-Lys49 (catalytically inactive) or sPLA2-Asp49 (catalytically active) into rat hindpaws each induced mechanical hyperalgesia (Randall–Selitto test), whereas only catalytically active sPLA2-Asp49 caused mechanical allodynia (von Frey test) Effects induced by both sPLA2s were inhibited by intrathecal fluorocitrate, a reversible glial metabolic inhibitor In support, immunohistochemical analysis revealed activation of dorsal horn astrocytes and microglia after intraplantar injection of either sPLA2 Spinal proinflammatory cytokines, nitric oxide, and prostanoids each appear to be involved in the pain-enhancing effects of these sPLA2s Blockade of interleukin-1 (IL1) inhibited hyperalgesia induced by both sPLA2s, while leaving allodynia unaffected Blockade of tumor necrosis factor reduced responses to sPLA2-Asp49 An inhibitor of neuronal nitric oxide synthase, 7-nitroindazole (7-NI), inhibited hyperalgesia induced by both sPLA2s, without interfering with allodynia induced by sPLA2-Asp49 On the other hand, l -N6-(1-iminoethyl)lysine ( l -NI), an inhibitor of the inducible nitric oxide synthase, did not alter any sPLA2-induced effect Lastly, celecoxib, an inhibitor of cyclooxygenase-2, attenuated sPLA2 actions These data provide the first evidence of spinal mediators involved in pain facilitation induced by subcutaneous venoms
TL;DR: The data suggest that the association between MI and adipose tissue AA is not related to dietary intake of (n-6) FAs including linoleic acid, and better understanding of the metabolic factors that increase AA in adipOSE tissue is urgently needed.
Abstract: Arachidonic acid (AA), a precursor of prothrombotic eicosanoids, is potentially atherogenic, but epidemiologic data are scarce. We evaluated the hypothesis that increased AA in adipose tissue is associated with increased risk of nonfatal acute myocardial infarction (MI), and if so, whether this association is related to dietary or adipose tissue linoleic acid. We studied the association between AA and MI in 466 cases of a first nonfatal acute MI, matched on age, gender, and residence to 466 population controls. Fatty acids (FA) were assessed by GC in adipose tissue samples collected from all subjects. Odds ratios (OR) and 95% CI were calculated from multivariate conditional logistic regression models. Subjects in the highest quintile of adipose tissue AA (0.64% of total FA) had a higher risk of nonfatal acute MI than those in the lowest quintile (0.29% of total FA), after adjusting for potential confounders including (n-3) and trans FAs (OR = 1.94, 95% CI: 1.07, 3.53, P for trend = 0.026). Adipose tissue AA was not correlated with dietary AA (r = 0.07), linoleic acid (r = 0.04), or other dietary (n-6) FAs, or with adipose tissue linoleic acid (r = -0.07). These data suggest that the association between MI and adipose tissue AA is not related to dietary intake of (n-6) FAs including linoleic acid. Better understanding of the metabolic factors that increase AA in adipose tissue is urgently needed.
13 Sep 2004
TL;DR: A mathematical proof of convergence of a multiobjective artificial immune system algorithm (based on clonal selection theory) is presented, based on the use of Markov chains.
Abstract: This paper presents a mathematical proof of convergence of a multiobjective artificial immune system algorithm (based on clonal selection theory). An specific algorithm (previously reported in the specialized literature) is adopted as a basis for the mathematical model presented herein. The proof is based on the use of Markov chains.
TL;DR: The heterozygote advantage experienced by females may be the most plausible explanation for the maintenance of this polymorphism in A. geoffroyi, and more studies need to evaluate social foraging behaviour and the performance of different phenotypes of other New World monkeys to determine if this is a global explanation for this phenomena.
Abstract: Most platyrrhine monkeys have an X-linked tri-allelic polymorphism for medium and long wavelength (M/L) sensitive cone photopigments. These pigments' sensitivity maxima (λmax) range from 535 to 562 nm. All animals also have an autosomally coded short-wavelength-sensitive (S) cone pigment. In populations with three M/L alleles there are six different colour vision phenotypes. Heterozygous females have trichromatic colour vision, while males and homozygous females are dichromats. The selective basis for this polymorphism is not understood, but is probably affected by the costs and benefits of trichromatic compared to dichromatic colour vision. For example, it has been suggested that trichromats are better equipped than dichromats to detect fruit against a leaf background. To investigate this possibility, we modeled fruit detection by various colour vision phenotypes present in the frugivorous spider monkey, Ateles geoffroyi. Our study population is thought to have three M/L alleles with cone pigment λmax values close to 535, 550 and 562 nm. The model predicted that all trichromat phenotypes had an advantage over dichromats, and the 535/562 nm phenotype was best; however, the model predicted that dichromats could detect all of the fruit species consumed by spider monkeys. We conclude that the heterozygote advantage experienced by females may be the most plausible explanation for the maintenance of this polymorphism in A. geoffroyi. Nevertheless, more studies need to evaluate social foraging behaviour and the performance of different phenotypes of other New World monkeys to determine if this is a global explanation for this phenomena or more specific to A. geofforyi.
TL;DR: In this paper, the core structures of spiroketal naphthodecalins are assembled by Barton's base mediated Ullmann binaphthyl ether coupling, Dakin reactions and hypervalent iodine spirocyclization.
Abstract: Spiroketal naphthodecalins are readily assembled by Barton's base mediated Ullmann binaphthyl ether coupling, Dakin reactions and hypervalent iodine spirocyclization. The core structures can be further diversified by enone addition and Stille coupling reactions. Nanomolar inhibitors for the Trx/TrxR redox control system were prepared by this approach and compared to series of natural product isolates. Cytotoxicity in MCF-7 cell assays ranged from an IC50 of 1.6 to >100 µM.
TL;DR: Toys entering a hospital can be contaminated with potentially dangerous bacteria and may provide unnecessary risks for nosocomial infection and effective measures must be implemented to prevent the spread of infections via toys.
TL;DR: Predictions of the lock and key and sexually antagonistic coevolution hypotheses were tested by studying the functional morphology of several male genitalic traits by freezing copulating pairs of four species of Drosophila.
Abstract: Several hypotheses attempt to explain why male genitalia typically diverge rapidly over evolutionary time. Predictions of the lock and key and the sexually antagonistic coevolution hypotheses were tested by studying the functional morphology of several male genitalic traits by freezing copulating pairs of four species of Drosophila: saltans, willistoni, melanogaster, and malerkotliana. Contrary to the predictions of the hypotheses, there were no species-specific differences in female morphology that corresponded to interspecific differences in the morphology of the male surstylus (which pressed and perhaps spread the distal tip of the oviscape), the epandrium (which grasped the external surface of the extended oviscape), and the aedeagus and paraphyses (which, in willistoni, clamped the oviscape). Antagonistic coevolution could possibly explain the diverse male genitalic morphology if female resistance behavior rather than morphology has coevolved with male morphology, but there are reasons doubt this explanation.
TL;DR: A new myotoxin was isolated from the venom of Bothrops atrox from Colombia, a mature product of 122 residues that belongs to the family of Lys49 phospholipase A(2) (PLA(2)) homologues, a subgroup of catalytically inactive proteins within the group IIA.
TL;DR: In this paper, a Ca(EDTA) complex in presence of phosphate ions was used to synthesize hydroxyapatite (HAp) at temperatures below 140 °C and at different pH values, and phase identification, crystallinity and morphology of obtained products were studied via FTIR, SEM, XRD and EDS.
TL;DR: The results demonstrate that the unfolded protein response remains functionally intact in cells with a 65% decrease in the cellular UDP-Glc level and provide evidence that this decrease is a stress signal in mammalian cells, which triggers the coordinate overexpression of mitochondrial and ER chaperones, independently of the ER stress elements.
TL;DR: H. pylori isolates were categorised as resistant to amoxicillin, clarithromycin and tetracycline when inhibition diameters were less than 25, 21 and 25 mm, respectively, in the disk diffusion assay.