Compression-induced crossovers for the ground state of classical dipole lattices on a Möbius strip.

We explore the ground-state properties of a lattice of classical dipoles spanned on the surface of a Möbius strip. The dipole equilibrium configurations depend significantly on the geometrical parameters of the Möbius strip, as well as on the lattice dimensions. As a result of the variable dipole spacing on the curved surface of the Möbius strip, the ground state can consist of multiple domains with different dipole orientations which are separated by domain-wall-like boundaries. We analyze in particular the dependence of the ground-state dipole configuration on the width of the Möbius strip and highlight two crossovers in the ground state that can be correspondingly tuned. A first crossover changes the dipole lattice from a phase which resists compression to a phase that favors it. The second crossover leads to an exchange of the topological properties of the two involved domains. We conclude with a brief summary and an outlook on more complex topologically intricate surfaces.

Suplementação gestacional na produção de lã de ovelhas e cordeiros / Gestacional supplementation in wool production of ewes and lambs

O objetivo deste estudo foi avaliar o efeito da suplementação durante diferentes períodos gestacionais sobre a produção de lã de ovelhas e cordeiros da raça Ideal. Foram utilizadas 53 ovelhas da raça Ideal, com escore corporal médio (3), inseminadas pela técnica de laparoscopia, com sêmen fresco de um único reprodutor; e seus cordeiros. Os tratamentos experimentais foram: sem suplementação (n=9); suplementação do início da gestação até 50 dias (n=11); suplementação dos 51 aos 100 dias de gestação (n=11); suplementação dos 101 aos 150 dias - final da gestação (n=11); e suplementação durante toda a gestação (n=11). A suplementação foi a 1,5% do peso corporal. Amostras de lã das ovelhas e dos cordeiros foram tomadas na região do costilhar esquerdo e enviadas ao laboratório para análises objetivas de finura de lã. As suplementações no terço final e durante toda a gestação proporcionavam os melhores resultados, com aumento de produção de lã e de peso das ovelhas. Ovelhas que receberam suplementação durante toda a gestação apresentaram maior diâmetro de fibra e peso corporal. O desempenho de lã dos cordeiros não foi influenciado pela alimentação de ovelhas durante a gestação.(AU)

The objective of this study was to evaluate the effect of supplementation during different gestational periods on the wool production of sheep and lambs of the Ideal breed. Fifty-three adult Ideal sheep were used, with a mean body score inseminated by the laparoscopy technique using fresh sperm from a single breeder and his lambs. Treatment groups: No supplementation (n=9); Supplementation in the beginning of gestation up to 50 days (n=11); Supplementation from 51 to 100 days of gestation (n=11); Supplementation from 101 to 150 days - end of gestation (n=11) ;and Supplementation throughout the gestation (n=11). The supplementation was at 1.5% of body weight. After birth, lambs were kept with their mothers in cultivated pasture of black oats and ryegrass. Wool samples from sheep and lambs were taken in the left-hand region and sent to the laboratory for objective analyzes of wool fineness. The supplementation performed in the final third and throughout the gestation provides the best results, with increased sheep weight. Ewes that received supplementation throughout pregnancy had greater fiber diameter and body weight. The wool performance of lambs was not influenced by feeding sheep during gestation.(AU)

One for all and all for one: retention of colour-unchanged old flowers increases pollinator attraction in a hermaphroditic plant.

Long-lived flowers increase pollen transfer rates, but these entail high water and carbon maintenance costs. The retention of pollinated and reward-free old flowers enhances pollinator visitation to young receptive flowers by increasing floral display size. This mechanism is associated with acropetal inflorescences or changes in flower colour and openness, but the retention of unchanging solitary flowers remains overlooked. We examined pollination-dependent variation in floral longevity and determined stigmatic receptivity, pollen viability and pollen removal rates among flower ages in Kielmeyera regalis, a Neotropical savanna shrub. We also evaluated the effects of floral display size on pollinator visitation rates. Lastly, we determined whether old flowers are unvisited and exclusively increase pollinator attraction to young flowers through flower removal experiments. Regardless of pollination treatment, flowers lasted fully open with no detectable physical changes for 3 days. Over time, stigmas remained receptive but >95% of pollen was removed. Pollinator visitation significantly increased with floral display size and intermediate percentages (15-30%) of newly opened flowers. Accordingly, the retention of reward-free and unvisited old flowers increased young flower-pollinator interaction. Our results reveal the importance of a prolonged floral longevity in increasing pollinator attraction toward newly opened receptive flowers without changes in flower colour and form. We conclude that the retention of pollinated, reward-free and unvisited colour-unchanged old flowers in K. regalis is a strategy that counteracts the water use costs associated with the maintenance of large flowers with increased mate opportunities in a pollen-limited scenario.

Reproductive phenology of Melastomataceae species with contrasting reproductive systems: contemporary and historical drivers.

Flowering and fruiting are key events in the life history of plants, and both are critical to their reproductive success. Besides the role of evolutionary history, plant reproductive phenology is regulated by abiotic factors and shaped by biotic interactions with pollinators and seed dispersers. In Melastomataceae, a dominant Neotropical family, the reproductive systems vary from allogamous with biotic pollination to apomictic, and seed dispersal varies from dry (self-dispersed) to fleshy (animal-dispersed) fruits. Such variety in reproductive strategies is likely to affect flowering and fruiting phenologies. In this study, we described the reproductive phenology of 81 Melastomataceae species occurring in two biodiversity hotspots: the Atlantic rain forest and the campo rupestre. We aim to disentangle the role of abiotic and biotic factors defining flowering and fruiting times of Melastomataceae species, considering the contrasting breeding and seed dispersal systems, and their evolutionary history. In both vegetation types, pollinator-dependent species had higher flowering seasonality than pollinator-independent ones. Flowering patterns presented phylogenetic signal regardless of vegetation type. Fruiting of fleshy-fruited species was seasonal in campo rupestre but not in Atlantic rain forest; the fruiting of dry-fruited species was also not seasonal in both vegetation types. Fruiting showed a low phylogenetic signal, probably because the influence of environment and dispersal agents on fruiting time is stronger than the phylogenetic affinity. Considering these ecophylogenetic patterns, our results indicate that flowering may be shaped by the different reproductive strategies of Melastomataceae lineages, while fruiting patterns may be governed mainly by the seed dispersal strategy and flowering time, with less phylogenetic influence.

Population structure of Annona crassiflora: an endemic plant species of the Brazilian Cerrado.

Habitat fragmentation has numerous consequences, particularly to endemic species, and has a negative impact on the genetic diversity of neglected species, leading to genetic drift. Annona crassiflora Mart. is a species that is endemic to Brazil, and its incidence in the Cerrado biome has decreased. The identification and characterization of its remaining diversity is necessary for its conservation. Our aim was to study the population structure of A. crassiflora populations from different Cerrado regions in Minas Gerais State, Brazil (Corinto, Curvelo, Carmo da Mata, Boa Esperança, and Paraguaçu) using inter-simple sequence repeat (ISSR) markers and DNA content. Nuclear DNA content was estimated by flow cytometry using 10 individuals from each population. ISSR markers were used for genotyping accessions in order to study their genetic diversity and population structures. We found considerable genetic variation among populations, with the highest variability observed in the Curvelo population. There was a significant positive correlation between DNA content and latitude (r = 0.46, P = 0. 0003). A Bayesian-based cluster analysis grouped the populations into three clusters, which followed their geographical origins. There was some level of genetic diversity and differentiation among the populations, suggesting the need for a conservation plan for this species. The ISSR markers and DNA content analysis were effective in studying the genetic diversity and population structure of A. crassiflora.

Pollen analysis of honey and pollen collected by Apis mellifera linnaeus, 1758 (Hymenoptera, Apidae), in a mixed environment of Eucalyptus plantation and native cerrado in Southeastern Brazil.

Eucalyptus plantations are frequently used for the establishment of bee yards. This study was carried on at Fazenda Brejão, northwestern region of the State of Minas Gerais, Brazil. This farm is covered both with native Cerrado vegetation (Brazilian savanna) and eucalyptus plantations. This paper reports on the botanic origin of pollen pellets and honey collected from honeybee (Apis mellifera) hives along a thirteen-month period (January 2004 to January 2005). The most frequent pollen types found in the pollen pellets during the rainy season were Trema micrantha (Ulmaceae), Copaifera langsdorffii (Fabaceae), an unidentified Poaceae, unidentified Asteraceae-2, Cecropia sp. 1 (Cecropiaceae) and Eucalyptus spp. (Myrtaceae); during the dry season the most frequent pollen types were Acosmium dasycarpum (Fabaceae), Cecropia sp. 1 (Cecropiaceae) and Eucalyptus spp. (Myrtaceae). Pollen grains of Baccharis sp. (Asteraceae), Cecropia sp. 1 (Cecropiaceae), Copaifera langsdorffii (Fabaceae), Mimosa nuda (Fabaceae), Eucalyptus spp. (Myrtaceae) and Trema micrantha (Ulmaceae) were present in the honey samples throughout the study period.

The association of HPV genotype with the regression, persistence or progression of low-grade squamous intraepithelial lesions.

BACKGROUND: Human papillomavirus (HPV) is a highly prevalent sexually transmitted virus causing cytological alterations that precede cervical cancer. Approximately 130 genotypes have been sequenced. Low-grade squamous intraepithelial lesions (LSIL) are the most frequent cytological alteration and have an uncertain behavior. OBJECTIVES: To analyze the frequency of HPV types in LSIL and their association with the regression, persistence or progression of these lesions. METHODS: A cohort study of forty patients with LSIL cytology was conducted from December 2007 to March 2011. The follow-up lasted two years and included cytology and colposcopy. HPV detection was performed using PCR, and genotyping was performed using PCR-specific and RFLP techniques. RESULTS: DNA-HPV was detected in 87% (35/40) of the cases, with oncogenic HPV accounting for 76%; type 16 in 32% (11/35) and type 18 in 20%. LSIL regression, persistence and progression rates at the end of the study were 60%, 23% and 17%, respectively. There was 50% regression in lesions in the high oncogenic risk group (types 16 and 18). CONCLUSION: HPV 16 was the most frequent genotype found in LSIL. The persistence and progression of the LSIL were related to the persistence of oncogenic HPV. The longer the follow-up time, the lower the LSIL persistence rate and the higher its regression rate; the progression rate remained stable. In addition to the presence of oncogenic HPV, other factors are necessary for the progression of LSIL.

Pollen analysis of honey and pollen collected by Apis mellifera linnaeus, 1758 (Hymenoptera, Apidae), in a mixed environment of Eucalyptus plantation and native cerrado in Southeastern Brazil / Espectro polínico do alimento coletado por Apis mellifera linnaeus, 1758 (hymenoptera, apidae), em ambiente contendo plantações de Eucalyptus e cerrado nativo no sudeste brasileiro

Abstract Eucalyptus plantations are frequently used for the establishment of bee yards. This study was carried on at Fazenda Brejão, northwestern region of the State of Minas Gerais, Brazil. This farm is covered both with native Cerrado vegetation (Brazilian savanna) and eucalyptus plantations. This paper reports on the botanic origin of pollen pellets and honey collected from honeybee (Apis mellifera) hives along a thirteen-month period (January 2004 to January 2005). The most frequent pollen types found in the pollen pellets during the rainy season were Trema micrantha (Ulmaceae), Copaifera langsdorffii (Fabaceae), an unidentified Poaceae, unidentified Asteraceae-2, Cecropia sp. 1 (Cecropiaceae) and Eucalyptus spp. (Myrtaceae); during the dry season the most frequent pollen types were Acosmium dasycarpum (Fabaceae), Cecropia sp. 1 (Cecropiaceae) and Eucalyptus spp. (Myrtaceae). Pollen grains of Baccharis sp. (Asteraceae), Cecropia sp. 1 (Cecropiaceae), Copaifera langsdorffii (Fabaceae), Mimosa nuda (Fabaceae), Eucalyptus spp. (Myrtaceae) and Trema micrantha (Ulmaceae) were present in the honey samples throughout the study period.

Resumo Plantações de Eucalyptus são, frequentemente, utilizadas como locais de instalação para colmeias. Este estudo foi realizado na Fazenda Brejão, localizada no noroeste de Minas Gerais, Brasil. Esta fazenda é coberta por Cerrado nativo (savana brasileira) e por plantações de eucaliptos. Este trabalho indica a origem botânica de bolotas e mel coletados em colmeias de Apis mellifera por um período de 13 meses (Janeiro/2004 a janeiro/2005). Os tipos polínicos mais frequentes nas amostras de pólen durante a estação chuvosa foram Trema micrantha (Ulmaceae), Copaifera langsdorffii (Fabaceae), Poaceae, Asteraceae não identificada 2, Cecropia sp. 1 (Cecropiaceae) e Eucalyptus spp. (Myrtaceae); na estação seca, os tipos polínicos mais frequentes foram Acosmium dasycarpum (Fabaceae), Cecropia sp. 1 (Cecropiaceae) e Eucalyptus spp. (Myrtaceae). As espécies Baccharis sp. (Asteraceae), Cecropia sp. 1 (Cecropiaceae), Copaifera langsdorffii (Fabaceae), Mimosa nuda (Fabaceae), Eucalyptus spp. (Myrtaceae) e Trema micrantha (Ulmaceae) estiveram presentes durante todo o período amostrado.

Reduced-rank models of growth and reproductive traits in Nelore cattle.

In beef cattle genetic evaluation, principal component models of the additive genetic effect could be used to incorporate several traits in the same analysis, without an important increase in the number of parameters to be estimated. In this study, multitrait (MT) and reduced-rank models were compared for their ability to estimate parameters and predict breeding values for weaning weight, yearling weight, weaning hip height, yearling hip height, weaning to yearling weight gain, scrotal circumference, and age at the first calving. Data obtained were from 74,388 Nelore animals, born to 1441 sires and 28,502 cows. Six analyses were performed using a MT model that incorporated all the traits simultaneously and five reduced-rank models for the genetic additive direct (co)variance matrix, fitting the first one (PC1), two (PC2), three (PC3), four (PC4), and five (PC5) principal components. The model considering the first three principal components (PC3) provided the best fit. Direct and maternal heritability and the respective standard errors obtained from the MT and PC3 models were similar. In general, the PC3 model provided slightly stronger genetic correlations between the traits when compared with those obtained with the MT model. The rank correlations between the breeding values predicted with the MT and PC3 models for the different traits ranged from 0.93 to 0.99. When 2% and 10% of the best sires were selected on the basis of breeding values predicted by the MT model, the degree of concordance with the PC3 model ranged from 86% to 97%. The first three principal components explained most of the genetic variation among animals, suggesting that major changes should not be expected in the sire's classification on the basis of breeding values predicted for growth and reproductive traits. Models of principal components could be used for beef cattle genetic evaluation, especially when considering several economic traits in the same analysis.

Phenotypic plasticity and similarity among gall morphotypes on a superhost, Baccharis reticularia (Asteraceae).

Understanding factors that modulate plant development is still a challenging task in plant biology. Although research has highlighted the role of abiotic and biotic factors in determining final plant structure, we know little of how these factors combine to produce specific developmental patterns. Here, we studied patterns of cell and tissue organisation in galled and non-galled organs of Baccharis reticularia, a Neotropical shrub that hosts over ten species of galling insects. We employed qualitative and quantitative approaches to understand patterns of growth and differentiation in its four most abundant gall morphotypes. We compared two leaf galls induced by sap-sucking Hemiptera and stem galls induced by a Lepidopteran and a Dipteran, Cecidomyiidae. The hypotheses tested were: (i) the more complex the galls, the more distinct they are from their non-galled host; (ii) galls induced on less plastic host organs, e.g. stems, develop under more morphogenetic constraints and, therefore, should be more similar among themselves than galls induced on more plastic organs. We also evaluated the plant sex preference of gall-inducing insects for oviposition. Simple galls were qualitative and quantitatively more similar to non-galled organs than complex galls, thereby supporting the first hypothesis. Unexpectedly, stem galls had more similarities between them than to their host organ, hence only partially supporting the second hypothesis. Similarity among stem galls may be caused by the restrictive pattern of host stems. The opposite trend was observed for host leaves, which generate either similar or distinct gall morphotypes due to their higher phenotypic plasticity. The Relative Distance of Plasticity Index for non-galled stems and stem galls ranged from 0.02 to 0.42. Our results strongly suggest that both tissue plasticity and gall inducer identity interact to determine plant developmental patterns, and therefore, final gall structure.

Does plant architectural complexity increase with increasing habitat complexity? A test with a pioneer shrub in the Brazilian Cerrado.

Understanding variation in plant traits in heterogeneous habitats is important to predict responses to changing environments, but trait-environment associations are poorly known along ecological gradients. We tested the hypothesis that plant architectural complexity increases with habitat complexity along a soil fertility gradient in a Cerrado (Neotropical savanna) area in southeastern Brazil. Plant architecture and productivity (estimated as the total number of healthy infructescences) of Miconia albicans (SW.) Triana were examined in three types of vegetation which together form a natural gradient of increasing soil fertility, tree density and canopy cover: grasslands (campo sujo, CS), shrublands (cerrado sensu strico, CE) and woodlands (cerradão, CD). As expected, plants growing at the CS were shorter and had a lower branching pattern, whereas plants at the CD were the tallest. Unexpectedly, however, CD plants did not show higher architectural complexity compared to CE plants. Higher architectural similarity between CE and CD plants compared to similarity between CS and CE plants suggests reduced expression of functional architectural traits under shade. Plants growing at the CE produced more quaternary shoots, leading to a larger number of infructescences. This higher plant productivity in CE indicates that trait variation in ecological gradients is more complex than previously thought. Nematode-induced galls accounted for fruit destruction in 76.5% infructescences across physiognomies, but percentage of attack was poorly related to architectural variables. Our data suggest shade-induced limitation in M. albicans architecture, and point to complex phenotypic variation in heterogeneous habitats in Neotropical savannas.

Langevin equations for competitive growth models.

Langevin equations for several competitive growth models in one dimension are derived. For models with crossover from random deposition (RD) to some correlated deposition (CD) dynamics, with small probability p of CD, the surface tension ν and the nonlinear coefficient λ of the associated equations have linear dependence on p due solely to this random choice. However, they also depend on the regularized step functions present in the analytical representations of the CD, whose expansion coefficients scale with p according to the divergence of local height differences when p→0. The superposition of those scaling factors gives ν~p(2) for random deposition with surface relaxation (RDSR) as the CD, and ν~p, λ~p(3/2) for ballistic deposition (BD) as the CD, in agreement with simulation and other scaling approaches. For bidisperse ballistic deposition (BBD), the same scaling of RD-BD model is found. The Langevin equation for the model with competing RDSR and BD, with probability p for the latter, is also constructed. It shows linear p dependence of λ, while the quadratic dependence observed in previous simulations is explained by an additional crossover before the asymptotic regime. The results highlight the relevance of scaling of the coefficients of step function expansions in systems with steep surfaces, which is responsible for noninteger exponents in some p-dependent stochastic equations, and the importance of the physical correspondence of aggregation rules and equation coefficients.

Analysis of human papillomavirus and Epstein-Barr virus infection and aberrant death-associated protein kinase methylation in high-grade squamous intraepithelial lesions.

This study was conducted to investigate the presence of Epstein-Barr virus (EBV) and human papillomavirus (HPV) and the promoter methylation status of the death-associated protein kinase (DAPK) gene in high-grade intraepithelial lesions. Viral infection was analyzed using polymerase chain reaction (PCR), and promoter methylation status was evaluated using chemical modification by sodium bisulfite followed by PCR. A total of 24 samples were studied. HPV was detected in 16.6%, EBV in 16.6%, and HPV/EBV coinfection in 16.6%. No virus infection was detected in 50% of the samples studied. DAPK promoter methylation was observed in 29.2% of the analyzed samples. There was no significant correlation between DAPK methylation and viral infection. DAPK methylation was detected in 28% of HPV-positive lesions, in 28% of HPV- and EBV-positive lesions, and in 44% (3/7) of the samples without viral infection. There was no observed methylation in samples with isolated EBV infection. In DAPK unmethylated samples, HPV infection was found in 12%, EBV infection in 23%, HPV/EBV coinfection in 12%, and an absence of HPV and EBV infection in 53%. The promoter methylation of the DAPK gene is an important event during carcinogenesis and may have potential clinical application as a marker for the progression and prognosis of cancer.

Surface and bulk properties of deposits grown with a bidisperse ballistic deposition model.

We study roughness scaling of the outer surface and the internal porous structure of deposits generated with the three-dimensional bidisperse ballistic deposition (BBD), in which particles of two sizes are randomly deposited. Systematic extrapolation of roughness and dynamical exponents and the comparison of roughness distributions indicate that the top surface has Kardar-Parisi-Zhang (KPZ) scaling for any ratio F of the flux between large and small particles. A scaling theory predicts the characteristic time of the crossover from random to correlated growth in BBD and provides relations between the amplitudes of roughness scaling and F in the KPZ regime. The porosity of the deposits monotonically increases with F and scales as F{12} for small F, which is also explained by the scaling approach and illustrates the possibility of connecting surface growth rules and bulk properties. The suppression of relaxation mechanisms in BBD enhances the connectivity of the deposits when compared to other ballisticlike models, so that they percolate down to F approximately 0.05. The fractal dimension of the internal surface of the percolating deposits is D{F} approximately 2.9, which is very close to the values in other ballistic-like models and suggests universality among these systems.

Constrictive chronic pericarditis in children.

Constrictive pericarditis is a uncommom disease in children. We have now encountered pericardial thickening as the cause of severe constrictive physiology in two patients, one also having haemodynamic features of restrictive cardiomyopathy. Both patients, who had refractory ascites and evidence of increased systemic venous pressure, underwent Doppler echocardiography, cardiac catheterisation, and magnetic resonance imaging. Resonance imaging failed to show any thickning of the pericardium, but cardiac catheterisation revealed diastolic equalisation of pressures in all four chambers, with only mild elevation of pulmonary pressure in the first patient, but nearly equalisation of diastolic pressure, and a very high pulmonary arterial pressure with a difference of 7 mm Hg between the end diastolic pressures in the two ventricles in the second patient. Doppler revealed a restrictive pattern of mitral inflow, with high E and small A velocities and a short deceleration time. The clinical background did not suggest pericardial disease in either of the patients. We conclude that a careful search is needed to uncover constrictive pericarditis when there is no previous disease which may suggest late pericardial constriction. The haemodynamic features of restrictive cardiomyopathy can co-exist with pericardial restriction, and differentiation between the two entities is critical in view of the diverse management and prognosis of the two conditions.

Hepatitis B virus surface antigen (HBsAg) and antibody (anti-HBs) forming immune complexes in fulminant hepatitis.

This paper reports an unusual pattern of serological HBV markers and the presence of HBsAg/anti-HBs immune complexes in serum samples from two patients with fulminant hepatitis from the Brazilian Western Amazon Basin. The diagnosis was made by both serologic tests and demonstration of antigen/antibody complexes by transmission electron microscopy. Concurrent Delta virus superinfection is also discussed.