Variational neural network ansatz for steady states in open quantum systems

We present a general variational approach to determine the steady state of open quantum lattice systems via a neural network approach. The steady-state density matrix of the lattice system is constructed via a purified neural network ansatz in an extended Hilbert space with ancillary degrees of freedom. The variational minimization of cost functions associated to the master equation can be performed using a Markov chain Monte Carlo sampling. As a first application and proof-of-principle, we apply the method to the dissipative quantum transverse Ising model.Comment: 6 pages, 4 figures, 54 references, 5 pages of Supplemental Information

A modified Brazilian test for the generalized-fracturetoughness determination in multimaterial corners. Numerical and experimental results

IX CONGRESO NACIONAL DE MATERIALES COMPUESTOS. Celebrado en Girona, 5, 6, 7 y 8 de julio de 2011In the present work, a general procedure for the experimental evaluation of the generalized fracture toughness in multimaterial corners is defined. The proposed method is suitable for closed corners (all material wedges being bonded) having two singular terms in the asymptotic stress representation at the corner tip. For a particular corner configuration, the method finds the load configuration at which one of the singular terms vanishes, thus the main stress contribution being controlled by the other non-vanishing singular term. The experimental test, until failure, using the previously defined load configuration allows the generalized fracture toughness associated to each singular term to be evaluated. The whole procedure has been applied to a bimaterial CFRP-Adhesive bimaterial corner and the generalized fracture toughness values have been obtained. The testing of mixed modes has permitted a failure envelope based on the generalized fracture toughness values at the corner tip to be defined. Previously published results, with different geometries, but involving the same corner, have shown that the failure envelope can predict accurately the failure initiation at these corners.Junta de Andalucía y Fondo Social Europeo P08-TEP-4071Junta de Andalucía y Fondo Social Europeo P08-TEP-4051Ministerio de Ciencia e Innovación MAT2009-14022CAPES Ministerio de Educación de Brasi

\u3ci\u3ePagamea\u3c/i\u3e Aubl. (Rubiaceae), from species to processes, building the bridge

Species delimitation have a great impact in scientific, environmental and other human activities, and is fundamental for understanding evolution. Plant species are usually delimited based on morphology and rarely species concepts are stated and analysis of variation made explicit. Botanists do see species as ?segments of evolutionary lineages?, but reproductive isolation is rarely addressed. Yet, reproductive isolation is necessary for understanding species, because speciation is the process of acquiring reproductive barriers. Almost any lineage will have species at different stages of isolation, and a single type of data will be insufficient for species delimitation. In plants, other biological processes such as hybridization, selfing and apomixis, make our search for species more challenging. If one focus on sympatry, reproductive isolation can be inferred, even if species are then defined only locally. If in a single locality putative species are distinct, then they must be reproductively isolated. Here, I first combine molecular phylogenetics (chloroplast and ITS), multivariate analyses of morphology, and sympatry for inferring reproductive isolation and delimiting species in Pagamea, a plant lineage from Tropical South America. I then used phylogenetic estimates of relationships to gain insights into the tempo and mode of speciation in this lineage. The results suggest 29 species in Pagamea. These include monophyletic and paraphyletic species, sympatric but cryptic species, and species that can be recognized only in a local sense. The ITS phylogeny best describes patterns of morphological, ecological and geographical variation, and the chloroplast shows a pattern consistent with the differential sorting of ancestral polymorphisms. Pagamea started diversifying ~ 10 million year ago and all speciation events took place before the Pleistocene (\u3e1.5 million years). Data exploration suggests peripatric speciation as the predominant mode in Pagamea, in agreement with the island-like distribution of its specific habitat (white-sand systems). Pagamea diversified along environmental gradients related to both flooding and altitude, with altitudinal shifts being phylogenetically more conserved than shifts for flooding levels. Eight new species of Pagamea are recognized and novel species circumscriptions are made. Hypothesis of species and intraspecific patterns of variation are also made explicit, and several interesting evolutionary scenarios emerge

Patient's reactions to digital rectal examination of the prostate

OBJECTIVE: In recent years, there has been a rise in the incidence of prostate cancer (PCa), and routine screening for the disease has become a well accepted clinical practice. Even with the recognized benefit of this approach, some men are still reluctant to undergo digital rectal examination (DRE). For this reason, we designed the present study in order to better understand men's reactions about this method of screening. The aim was to identify possible drawbacks that could be overcome to increase DRE. MATERIALS AND METHODS: We randomly selected 269 patients that were enrolled in an institutional PCa screening program. They were first asked to answer a question regarding their preferred position to undergo the examination. Following this step, they answered a questionnaire in which physical and psychological reactions regarding the DRE were presented. Finally, we used a visual analogical scale (VAS) to analyze the perception of pain during DRE. RESULTS: The supine position was preferred for most patients (53.9%). Before DRE, about 59.4% of patients felt that the exam would be acceptable. After DRE, this figure increased to 91.5% (p < 0.001). Mean VAS score during DRE was 1.69 on a scale with a range between 0 and 10 (0 = no pain; 10 = extreme pain). CONCLUSION: Patient expectations about DRE were negative before examination and changed significantly following the exam. Pain during examination was negligible, contrary to the prevalent belief. These two findings must be clearly presented to patients in order to improve PCa screening acceptance

Learning and knowledge transfer by humans and digital platforms: which tools best support the decision-making process?

Purpose – This study aims to investigate the impact of technologies on the knowledge transfer process. In particular, the authors aim to analyze the topic of knowledge brokers and the relationship between broker and digital tools in the knowledge transfer process in the sport context. The study developed, therefore, aims to investigate the creating of this environment for knowledge transfer and knowledge sharing between man and machine, looking to improve the planning of technical sports projects of the clubs. Design/methodology/approach – This paper presents a qualitative approach aimed at analyzing how platforms and the players’ agents can be useful tools in the knowledge transfer process. The research was conducted through a survey with a structured questionnaire via e-mail to 64 managers at the head of clubs playing in the Italian Series B basketball in the 2021–2022 championship. The total number of questions administered is 21. Findings – The results demonstrate how sports directors, for the construction of a technical sports project, in addition to learning off the pitch by interactions with media, fans, pressure management, leadership skills, positive attitude, tolerance, understanding of other opinions, background and cultures, see the athletes’ agents as the main stakeholder of the managers. The research resulted, by the clubs’ managers, in both formal learning and informal-type learning. Informal learning, by far the most frequently used and most important in the general learning process of executives, is identified in the use that executives make of information available on digital platforms and of the fiduciary relationships that management has with players’ agents. Originality/value – The results demonstrate the valuable opportunities for executives, coaches, managers and clubs to strategically manage learning and knowledge sharing. Improving and managing knowledge-sharing strategies would help increase knowledge, not only of the sports directors but also of the entire club, thus improving the absolute quality of the game within the Italian basketball divisions. The authors have developed an innovative framework regarding the construction of a ‘‘typed sports technical project’’, and the authors have identified a series of crucial phases capable of determining the creation of a new roster of athletes

Características estruturais e ultraestruturais da espermatogênese do cascudo-cinza Liposarcus anisitsi (Holmberg, 1893) (Teleostei, Siluriformes)

Liposarcus anisitsi é um teleósteo de água doce da ordem Siluriforme, com fertilização externa, possui um processo de espematogênese cística com estrutura espermatogonial lobular irrestrita dos testículos. Nesta espécie, a espermatogônia primária intracística ou isolada é considerada como a "stem cell" da linhagem espermatogenética. Então, como consequência do processo da espermatogênese cística de Liposarcus anisitsi todas as três células germinativas são observadas no interior de cistos espermatogenéticos específicos, desde as espermatogônias primárias e secundárias até os espermatócitos e espermátides jovens e maduras. A espermatogônia possui forma esférica, com núcleo central e grande quantidade de mitocôndrias redondas e retículo endoplasmático, principalmente do tipo rugoso, em seu citoplasma. Os espermatócitos primários se inter-relacionam através de pontes citoplasmáticas e são claramente identificados pela presença de complexos sinaptonêmicos no interior de seus núcleos. Espermátides jovens no início da fase maturacional, tanto quanto as espermátides maduras tendem a exibir núcleos esféricos, um modelo variável de progressiva condensação cromatínica durante o estágio final da espermiogênese. Nestes estágios finais, as espermátides maduras mostra uma fossa nuclear formada para a fixação do flagelo. O espermatozóide de Liposarcus anisitsi possui cabeça redonda, núcleo redondo, cromatina densa, ausência de acrossoma, curta peça intermediária e longa cauda (peças principal e terminal do flagelo).Liposarcus anisitsi is a freshwater teleost from Siluriform order with external fertilization that shows cystic spermatogenesis process with spermatogonial unrestricted lobular structure of the testes. In this species, isolated or intracystic primary spermatogonia were noted as the ¨stem cells¨ of the spermatogenetic lineage. Thus, as consequence of the cystic spermatogenesis process of Liposarcus anisitsi all the three germinative cells are observed inside specific spermatogenetic cysts, since the primary and secondary spermatogonias until the spermatocytes and early and late spermatids. Spermatogonia show spherical shape with central nuclei and great amount of round mitochondria and ER profiles mainly of rough type in their cytoplasm. Primary spermatocytes have inter-relations through cytoplasmic bridges and are clearly identified by presence of synaptonemic complexes inside the nuclei. Early spermatids beginning maturational phases, as well as the late spermatids, tend to exhibit spherical nuclei, variable chromatin pattern with progressive condensation during the end steps of the spermiogenesis. In this end steps, the late spermatids show the nuclear fossa formed to the fixation of the flagella. The spermatozoon of Liposarcus anisitsi shows round head, round nuclei, very dense chromatin, lack of acrosoma, short middle piece and long tail (principal and end pieces of the flagellum)

Revisiting the hyperdominance of Neotropical tree species under a taxonomic, functional and evolutionary perspective

Recent studies have leveraged large datasets from plot-inventory networks to report a phenomenon of hyperdominance in Amazonian tree communities, concluding that few species are common and many are rare. However, taxonomic hypotheses may not be consistent across these large plot networks, potentially masking cryptic diversity and threatened rare taxa. In the current study, we have reviewed one of the most abundant putatively hyperdominant taxa, Protium heptaphyllum (Aubl.) Marchand (Burseraceae), long considered to be a taxonomically difficult species complex. Using morphological, genomic, and functional data, we present evidence that P. heptaphyllum sensu lato may represent eight separately evolving lineages, each warranting species status. Most of these lineages are geographically restricted, and few if any of them could be considered hyperdominant on their own. In addition, functional trait data are consistent with the hypothesis that trees from each lineage are adapted to distinct soil and climate conditions. Moreover, some of the newly discovered species are rare, with habitats currently experiencing rapid deforestation. We highlight an urgent need to improve sampling and methods for species discovery in order to avoid oversimplified assumptions regarding diversity and rarity in the tropics and the implications for ecosystem functioning and conservation

Polinização de Pagamea duckei Standl. (Rubiaceae): Uma espécie funcionalmente dióica

The floral biology, pollination and breeding system of Pagamea duckei Standl. (Rubiaceae) were studied at the Reserva Biológica da Campina, Manaus, Amazonas, Brazil. Floral morphology suggested that P. duckei is a distylous species. However, crossing experiments revealed that it is functionally dioecious. The flowers are actinomorphic, yellowish, produce nectar and a sweet odor, which is more intense in the morning. Anthesis started in the morning between 5.00 and 6.00 AM and extended until dusk, when the corolla tube abscissed. The flowers were visited mostly by bees of the genus Melipona. Pagamea duckei is not agamospermic and thus needs pollen vectors for effective pollination. The results of this study strengthen the idea that, in Pagamea, species with distylous flower morphology are actually functionally dioecious