15,367 research outputs found

    Paradox in Wave-Particle Duality

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    We report on the simultaneous determination of complementary wave and particle aspects of light in a double-slit type "welcher-weg" experiment beyond the limitations set by Bohr's Principle of Complementarity. Applying classical logic, we verify the presence of sharp interference in the single photon regime, while reliably maintaining the information about the particular pinhole through which each individual photon had passed. This experiment poses interesting questions on the validity of Complementarity in cases where measurements techniques that avoid Heisenberg's uncertainty principle and quantum entanglement are employed. We further argue that the application of classical concepts of waves and particles as embodied in Complementarity leads to a logical inconsistency in the interpretation of this experiment

    A metagenomic assessment of the bacteria associated with Lucilia sericata and Lucilia cuprina (Diptera: Calliphoridae)

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    Lucilia Robineau-Desvoidy (Diptera: Calliphoridae) is a blow fly genus of forensic, medical, veterinary, and agricultural importance. This genus is also famous because of its beneficial uses in maggot debridement therapy (MDT). Although the genus is of considerable economic importance, our knowledge about microbes associated with these flies and how these bacteria are horizontally and trans-generationally transmitted is limited. In this study, we characterized bacteria associated with different life stages of Lucilia sericata (Meigen) and Lucilia cuprina(Wiedemann) and in the salivary gland of L. sericata by using 16S rDNA 454 pyrosequencing. Bacteria associated with the salivary gland of L. sericata were also characterized using light and transmission electron microscopy (TEM). Results from this study suggest that the majority of bacteria associated with these flies belong to phyla Proteobacteria, Firmicutes, andBacteroidetes, and most bacteria are maintained intragenerationally, with a considerable degree of turnover from generation to generation. In both species, second-generation eggs exhibited the highest bacterial phylum diversity (20 % genetic distance) than other life stages. The Lucilia sister species shared the majority of their classified genera. Of the shared bacterial genera, Providencia, Ignatzschineria, Lactobacillus, Lactococcus, Vagococcus, Morganella, and Myroides were present at relatively high abundances. Lactobacillus, Proteus,Diaphorobacter, and Morganella were the dominant bacterial genera associated with a survey of the salivary gland of L. sericata. TEM analysis showed a sparse distribution of both Gram-positive and Gram-negative bacteria in the salivary gland of L. sericata. There was more evidence for horizontal transmission of bacteria than there was for trans-generational inheritance. Several pathogenic genera were either amplified or reduced by the larval feeding on decomposing liver as a resource. Overall, this study provides information on bacterial communities associated with different life stages of Lucilia and their horizontal and trans-generational transmission, which may help in the development of better vector-borne disease management and MDT methods

    A high-affinity antibody against the CSP N-terminal domain lacks Plasmodium falciparum inhibitory activity

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    Malaria is a global health concern and research efforts are ongoing to develop a superior vaccine to RTS,S/AS01. To guide immunogen design, we seek a comprehensive understanding of the protective humoral response against Plasmodium falciparum circumsporozoite protein (PfCSP). In contrast to the well-studied responses to the repeat region and the C-terminus, the antibody response against the N-terminal domain of PfCSP (N-CSP) remains obscure. Here, we characterized the molecular recognition and functional efficacy of the N-CSP-specific monoclonal antibody 5D5. The crystal structure at 1.85 Åresolution revealed that 5D5 binds an α-helical epitope in N-CSP with high affinity through extensive shape and charge complementarity, and the unusual utilization of an N-linked glycan. Nevertheless, functional studies indicated low 5D5 binding to live Pf sporozoites, and lack of sporozoite inhibition in vitro and in mosquitoes. Overall, our data on low recognition and inhibition of sporozoites do not support the inclusion of the 5D5 epitope into the next generation of CSP-based vaccines.Summary Statement The Plasmodium falciparum sporozoite surface protein, PfCSP, is an attractive vaccine target, but the antibody response against the CSP N-terminal domain has remained understudied. Here, to guide immunogen design, Thai et al. provide insights into the binding motif and functional efficacy of the N-terminal domain-specific monoclonal antibody, 5D5

    CAUSAS DE EXCLUSÃO DE DOADORES VIVOS DE RIM NO SERVIÇO DE TRANSPLANTE DE UM HOSPITAL DE TERCEIRO NÍVEL NO NOROESTE DO MÉXICO

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    Objective: To identify the causes for exclusion of living kidney donors at a third-level hospital in northwestern Mexico. Materials and methods: An observational, cross-sectional, descriptive and retrospective study, in which the medicalrecords of candidates for living kidney donation were evaluated from January 1, 2019 to December 31, 2021. Results: Out of the 30 selected records, only 6.6 % (2) were chosen as donors, i.e., the rejection rate of the potential candidates was 93.3 % (28). The average age was 40.7 years; when divided into age groups, it was observed that 7.44 % were ≤ 39 years, 5.31 % were ≥ 50 years and 4.25 % were in the 40–49 age range. The main pathologies that caused therejection of living donors were chronic diseases such as unknown renal disease, obesity, diabetes mellitus, systemic hypertension and heart diseases, which accounted for 60.7 %. The desire to donate was more frequent among blood relatives than non-blood relatives. In the case of blood relatives, i.e., siblings, parents, children, uncles, aunts, etc., 64.2 % were rejected, while 34.7 % of non-blood relatives, including spouses and friends, were rejected.Conclusions: Based on the body mass index (BMI), the results showed that overweight and obesity were the main causes of exclusion, a situation that is consistent with the Mexican epidemiological profile. The number of living donors at ourcenter has been reduced because most of the population is not healthy and has obesity, which affects the willingness to be a candidate for living kidney donation.Objetivo: Identificar las causas de exclusión de los donantes renales vivos en un centro hospitalario de tercer nivel en el noroeste de México.Materiales y métodos: Estudio de tipo observacional, transversal, descriptivo, retrospectivo. Se realizó la evaluación de los expedientes clínicos de los candidatos vivos para donación renal, que abarcó el periodo comprendido entre el 1 de enero de 2019 y el 31 de diciembre de 2021. Resultados: De los 30 expedientes seleccionados, solo se eligieron 2 (6,6 %) donadores, es decir, existió un índice de rechazo de 28 (93,3 %) de los potenciales candidatos. La edad promedio fue de 40,7 años; al dividirlos en grupos de edad, se observó que el 7,44 % fueron ≤39 años; el 5,31 %, ≥50 años; y el 4,25 %, de 40 a 49 años. Dentro de las principales patologías que originaron el rechazo del donador vivo se encuentran las enfermedades crónicas, como afección renal desconocida, obesidad, diabetes mellitus, hipertensión arterial sistémica y cardiopatías, que representaron el 60,7 %. El deseo de donares más frecuente entre consanguíneos que en no consanguíneos. En el caso de los consanguíneos, es decir, hermanos, padres, hijos, tíos, etc., el 64,2 % fue rechazado; en los no consanguíneos, el 34,7 %, que incluía a esposos y amigos. Conclusiones: Los resultados obtenidos sobre el índice de masa corporal (IMC) mostraron que el sobrepeso y laobesidad fueron las principales causas de exclusión, circunstancia que es particular en nuestro país respecto a su perfil epidemiológico. La cantidad de donantes vivos en nuestro centro se redujo porque la mayor parte de la población no es sana, padece obesidad y ello repercute al momento de presentarse como candidato a donante.Resumo Objetivo: Identificar as causas de exclusão de doadores vivos de rim. Material e métodos: Estudo observacional, transversal, descritivo, retrospectivo, no qual é realizada a análise dos prontuários de possíveis doadores de rim no período de 1º de janeiro de 2019 a 31 de dezembro de 2021. Identificar diagnósticos que excluam uma pessoa como doador. Resultados: Dos 30 arquivos selecionados, apenas 2 (6,6%) foram escolhidos como doadores, ou seja, houve uma taxa de rejeição de 28 (93,3%). Os principais motivos de rejeição foram doenças crônicas, indicando 60,7% em que se encontraram doença renal desconhecida, obesidade, diabetes mellitus, hipertensão arterial sistêmica e cardiopatia. Conclusão: Os resultados obtidos no índice de massa corporal (IMC) mostraram o sobrepeso e a obesidade como uma das principais causas de exclusão com 21,4%, informação semelhante à de Lapasia et al., que descreve a obesidade como a principal causa de rejeição representando quase 40% dos doadores. Ezzaki et al, também a descrevem como causa de exclusão

    Effectiveness and Adoption of a Drawing-to-Learn Study Tool for Recall and Problem Solving: Minute Sketches with Folded Lists

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    Drawing by learners can be an effective way to develop memory and generate visual models for higher-order skills in biology, but students are often reluctant to adopt drawing as a study method. We designed a nonclassroom intervention that instructed introductory biology college students in a drawing method, minute sketches in folded lists (MSFL), and allowed them to self-assess their recall and problem solving, first in a simple recall task involving non-European alphabets and later using unfamiliar biology content. In two preliminary ex situ experiments, students had greater recall on the simple learning task, non-European alphabets with associated phonetic sounds, using MSFL in comparison with a preferred method, visual review (VR). In the intervention, students studying using MSFL and VR had similar to 50-80% greater recall of content studied with MSFL and, in a subset of trials, better performance on problem-solving tasks on biology content. Eight months after beginning the intervention, participants had shifted self-reported use of drawing from 2% to 20% of study time. For a small subset of participants, MSFL had become a preferred study method, and 70% of participants reported continued use of MSFL. This brief, low-cost intervention resulted in enduring changes in study behavior

    Delocalization in Continuous Disordered Systems

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    Continuous One-dimensional models supporting extended states are studied. These delocalized statesoccur at well defined values of the energy and are consequences of simple statistical correlation rules. We explicitly study alloys of delta-barrier potentials as well as alloys and liquids of quantum well as.The divergence of the localization length is studied and a critical exponent 2/3 is found for the delta-barrier case, whereas for the quantum wells we find an exponent of 2 or 2/3 depending on the well's parameters. These results support the idea that correlations between random scattering sequences break Anderson localization. We further calculate the conductance of disordered superlattices. At the peak transmission the relative fluctuations of the transmission coefficient are vanishing.Comment: 8 page

    Diffusion in disordered systems under iterative measurement

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    We consider a sequence of idealized measurements of time-separation Δt\Delta t onto a discrete one-dimensional disordered system. A connection with Markov chains is found. For a rapid sequence of measurements, a diffusive regime occurs and the diffusion coefficient DD is analytically calculated. In a general point of view, this result suggests the possibility to break the Anderson localization due to decoherence effects. Quantum Zeno effect emerges because the diffusion coefficient DD vanishes at the limit Δt0\Delta t \to 0.Comment: 8 pages, 0 figures, LATEX. accepted in Phys.Rev.
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