Quantum discrete breathers

We review recent studies about quantum discrete breathers. We describe their basic properties in comparison with their classical counterparts, and the ways they may be addressed theoretically in different quantum lattice models including either bosonic or fermionic excitations. We also review recent experimental work in the field.Comment: 49 pages, 36 figures, some corrected typos, and the section "Conclusions and outlook" was added. Chapter for a book edited by S. Keshavamurthy and P. Schlagheck with title "Dynamical Tunneling: Theory and Experiment

Edge-localized states in quantum one-dimensional lattices

In one-dimensional quantum lattice models with open boundaries, we find and study localization at the lattice edge. We show that edge-localized eigenstates can be found in both bosonic and fermionic systems, specifically, in the Bose-Hubbard model with on-site interactions and in the spinless fermion model with nearest-neighbor interactions. We characterize the localization through spectral studies via numerical diagonalization and perturbation theory, through considerations of the eigenfunctions, and through the study of explicit time evolution. We concentrate on few-particle systems, showing how more complicated edge states appear as the number of particles is increased.Comment: 9 pages, 12 figure

Winter sowing and higher populations as dry-farming strategies on sunflower crop (Helianthus annuus L.)

Sunflower is sown in early spring (March-April) under Mediterranean dryland conditions. Plant development is coincidental with increasing air temperature and crop ET and usually reproduction occurs under water and temperature stresses, resulting in severe yield limitations (Downes 1975, Carvalho et al 1990, 1991). As a strategy of stress avoidance during the reproductive stages winter sowing (late December and January) has been successfully tested (Vesperinas et al 1991, Ordonez 1990). This experiment tested the potential advantage in anticipating sowing date to late December or January, and in increasing plant population in order to use soil water more efficiently

Pms2 suppresses large expansions of the (GAA·TTC)n sequence in neuronal tissues

Copyright @ 2012 Bourn et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.Expanded trinucleotide repeat sequences are the cause of several inherited neurodegenerative diseases. Disease pathogenesis is correlated with several features of somatic instability of these sequences, including further large expansions in postmitotic tissues. The presence of somatic expansions in postmitotic tissues is consistent with DNA repair being a major determinant of somatic instability. Indeed, proteins in the mismatch repair (MMR) pathway are required for instability of the expanded (CAG·CTG)(n) sequence, likely via recognition of intrastrand hairpins by MutSβ. It is not clear if or how MMR would affect instability of disease-causing expanded trinucleotide repeat sequences that adopt secondary structures other than hairpins, such as the triplex/R-loop forming (GAA·TTC)(n) sequence that causes Friedreich ataxia. We analyzed somatic instability in transgenic mice that carry an expanded (GAA·TTC)(n) sequence in the context of the human FXN locus and lack the individual MMR proteins Msh2, Msh6 or Pms2. The absence of Msh2 or Msh6 resulted in a dramatic reduction in somatic mutations, indicating that mammalian MMR promotes instability of the (GAA·TTC)(n) sequence via MutSα. The absence of Pms2 resulted in increased accumulation of large expansions in the nervous system (cerebellum, cerebrum, and dorsal root ganglia) but not in non-neuronal tissues (heart and kidney), without affecting the prevalence of contractions. Pms2 suppressed large expansions specifically in tissues showing MutSα-dependent somatic instability, suggesting that they may act on the same lesion or structure associated with the expanded (GAA·TTC)(n) sequence. We conclude that Pms2 specifically suppresses large expansions of a pathogenic trinucleotide repeat sequence in neuronal tissues, possibly acting independently of the canonical MMR pathway.IDB was supported by a postdoctoral fellowship from the National Ataxia Foundation. RMP was supported by Ataxia UK. SA was supported by The Wellcome Trust. This research was made possible by grants from the National Institutes of Health (NIH/NINDS) and the Muscular Dystrophy Association to S.I.B

Anaplastic thyroid cancer: how far can we go?

Globally, thyroid cancer accounts for 2 % of all cancer diagnoses, and can be classified as well-differentiated or undifferentiated. Currently, differentiated thyroid carcinomas have good prognoses, and can be treated with a combination of therapies, including surgical thyroidectomy, radioactive iodine therapy and hormone-based therapy. On the other hand, anaplastic thyroid carcinoma, a subtype of undifferentiated thyroid carcinoma characterized by the loss of thyroid-like phenotype and function, does not respond to either radioactive iodine or hormone therapies. In most cases, anaplastic thyroid carcinomas are diagnosed in later stages of the disease, deeming them inoperable, and showing poor response rates to systemic chemotherapy. Recently, treatment courses using multiple-target agents are being explored and clinical trials have shown very promising results, such as overall survival rates, progression-free survival and tumor shrinkage. This review is focused on thyroid carcinomas, with particular focus on anaplastic thyroid carcinoma, exploring its undifferentiated nature. Special interest will be given to the treatment approaches currently available and respective obstacles or drawbacks. Our purpose is to contribute to understand why this malignancy presents low responsiveness to current treatments, while overviewing novel therapies and clinical trials.This research was funded by Fundação para a Ciência e a Tecnologia (FCT) through the Project Reference UID/DTP/04138/2019.info:eu-repo/semantics/publishedVersio

Anaplastic thyroid cancer: How far can we go?

This research was funded by Fundacao para a Ciencia e a Tecnologia (FCT) through the Project Reference UID/DTP/04138/2019.Globally, thyroid cancer accounts for 2 % of all cancer diagnoses, and can be classified as well-differentiated or undifferentiated. Currently, differentiated thyroid carcinomas have good prognoses, and can be treated with a combination of therapies, including surgical thyroidectomy, radioactive iodine therapy and hormone-based ther-apy. On the other hand, anaplastic thyroid carcinoma, a subtype of undifferentiated thyroid carcinoma character-ized by the loss of thyroid-like phenotype and function, does not respond to either radioactive iodine or hormone therapies. In most cases, anaplastic thyroid carcinomas are diagnosed in later stages of the disease, deeming them inoperable, and showing poor response rates to systemic chemotherapy. Recently, treatment courses using multi-ple-target agents are being explored and clinical trials have shown very promising results, such as overall survival rates, progression-free survival and tumor shrinkage. This review is focused on thyroid carcinomas, with particular focus on anaplastic thyroid carcinoma, exploring its undifferentiated nature. Special interest will be given to the treatment approaches currently available and respective obstacles or drawbacks. Our purpose is to contribute to understand why this malignancy presents low responsiveness to current treatments, while overviewing novel therapies and clinical trials.publishersversionpublishe

Projecto Rodentia : etologia aplicada na sala de aula do 1º Ciclo

p. 275-279O Projecto Rodentia, implementado no ano 2006/2007, visa promover a cultura científica em alunos do 1º ciclo do Ensino Básico, familiarizando-os com o Método Científico e desenvolvendo competências conceptuais, processuais e atitudinais, com base na Etologia Aplicada e na reflexão ética sobre o bem-estar animal. Foram instalados em três salas de aula habitats especialmente desenhados, contendo cada um dois ratos de laboratório. Inicialmente orientadas, as crianças começaram de modo progressivamente autónomo a propor actividades experimentais, registar e interpretar resultados e tirara conclusões, tacitamente aprendendo o Método Científico. Recorreu-se à observação comportamental e análise de trabalhos dos alunos para avaliar o desenvolvimento da lógica condicional nestes alunos

A microbiological perspective of raw milk preserved at room temperature using hyperbaric storage compared to refrigerated storage

The effects of hyperbaric storage (HS, 50–100 MPa) at room temperature (RT) on endogenous and inoculated pathogenic surrogate vegetative bacteria (Escherichia coli, Listeria innocua), pathogenic Salmonella enterica and bacterial spores (Bacillus subtilis) were assessed and compared with conventional refrigeration at atmospheric pressure for 60 days. Milk stored at atmospheric pressure and refrigeration quickly surpassed the acceptable microbiological limit within 7 days of storage, regarding endogenous microbiota, yet 50 MPa/RT slowed down microbial growth, resulting in raw milk spoilage after 28 days, while a significant microbial inactivation occurred under 75–100 MPa (around 4 log units), to counts below 1 log CFU/mL throughout storage, similar to what was observed for B. subtilis endospores. While inoculated microorganisms had a gradually counts reduction in all HS conditions. Results indicate that HS can not only result in the extension of milk shelf-life but is also able to enhance its safety and subsequent quality. Industrial relevance: This new preservation methodology could be implemented in the dairy farm storage tanks, or during milk transportation for further processing, allowing a better microbial control, than refrigeration. This methodology is very promising, and can improve food products shelf-life with a considerable lower carbon foot-print than refrigeration.info:eu-repo/semantics/publishedVersio

Neotropical club-tailed scorpions.

134 pages : illustrations (some color), maps ; 26 cm.The Neotropical "club-tailed" scorpions of the genus Rhopalurus Thorell, 1876, and two related genera in family Buthidae C.L. Koch, 1837, i.e., Physoctonus Mello-Leitão, 1934, and Troglorhopalurus Lourenço et al., 2004, are revised, based on a simultaneous phylogenetic analysis of 90 morphological characters and 4260 aligned DNA nucleotides from three mitochondrial and two nuclear gene loci. The monophyletic New World buthid subfamily Rhopalurusinae Bucherl, 1971, to which these scorpions were originally assigned, is redefined, revised diagnoses and a key to identification of its genera and species (except for Centruroides Marx, 1890) provided, and their distributions mapped. The paraphyly of Rhopalurus Thorell, 1876, which comprises several monophyletic groups congruent with its disjunct distribution, justifies its relimitation and that of Troglorhopalurus Lourenço et al., 2004, the revalidation of Heteroctenus Pocock, 1893, and creation of Ischnotelson, gen. nov. (type species: Rhopalurus guanambiensis Lenarducci, Pinto-da-Rocha and Lucas, 2005) and Jaguajir, gen. nov. (type species: Rhopalurus agamemnon C.L. Koch, 1839). Ten new combinations are proposed: Heteroctenus abudi (Armas and Marcano Fondeur, 1987), comb. nov.; Heteroctenus bonettii (Armas, 1999), comb. nov.; Heteroctenus garridoi (Armas, 1974), comb. nov.; Heteroctenus gibarae (Teruel, 2006), comb. nov.; Heteroctenus princeps (Karsch, 1879), comb. nov.; Ischnotelson guanambiensis (Lenarducci, Pinto-da-Rocha and Lucas, 2005), comb. nov.; Jaguajir agamemnon (C.L. Koch, 1839), comb. nov.; Jaguajir pintoi (Mello-Leitão, 1932), comb. nov.; Jaguajir rochae (Borelli, 1910), comb. nov.; Troglorhopalurus lacrau (Lourenço and Pinto-da-Rocha, 1997), comb. nov. Three new species are described: Ischnotelson peruassu, sp. nov. (type locality: Parque Estadual do Peruassu, Minas Gerias, Brazil); Physoctonus striatus, sp. nov. (type locality: Castelo do Piauí, Piauí, Brazil); Rhopalurus ochoai, sp. nov. (type locality: San Agustín, Edo. Zulia, Venezuela). Fifteen new junior subjective synonyms are proposed: Rhopalurus acromelas Lutz and Mello, 1922, Rhopalurus melleipalpus Lutz and Mello, 1922, Rhopalurus iglesiasi Werner, 1927, Rhopalurus lambdophorus Mello-Leitão, 1932, Rhopalurus dorsomaculatus Prado, 1938, and Rhopalurus goiasensis Prado, 1940 = Jaguajir agamemnon (C.L. Koch, 1839); Rhopalurus pintoi kourouensis Lourenço, 2008 = Jaguajir pintoi (Mello-Leitão, 1932); Rhopalurus crassicauda Caporiacco, 1947, Rhopalurus amazonicus Lourenço, 1986, and Rhopalurus crassicauda paruensis Lourenço, 2008 = Rhopalurus laticauda Thorell, 1876; Rhopalurus melloleitaoi Teruel and Armas, 2006, and Rhopalurus aridicola (Teruel and Armas, 2012) = Heteroctenus junceus (Herbst, 1800); Rhopalurus granulimanus Teruel, 2006 = Heteroctenus gibarae (Teruel, 2006); Rhopalurus virkii Santiago-Blay, 2009 = Heteroctenus abudi (Armas and Marcano Fondeur, 1987); Rhopalurus brejo Lourenço, 2014 = Troglorhopalurus lacrau (Lourenço and Pinto-da-Rocha, 1997)