1,325 research outputs found
Movement patterns and athletic performance of leopards in the Okavango Delta
Although leopards are the most widespread of all the big cats and are known for their adaptability, they are elusive and little is known in detail about their movement and hunting energetics. We used high-resolution GPS/IMU (inertial measurement unit) collars to record position, activity and the first high-speed movement data on four male leopards in the Okavango Delta, an area with high habitat diversity and habitat fragmentation. Leopards in this study were generally active and conducted more runs during the night, with peaks in activity and number of runs in the morning and evening twilight. Runs were generally short (less than 100 m) and relatively slow (maximum speed 5.3 m s−1, mean of individual medians) compared to other large predators. Average daily travel distance was 11 km and maximum daily travel distance was 29 km. No direct correlation was found between average daily temperature and travel distance or between season and travel distance. Total daily energy requirements based on locomotor cost and basal metabolic rate varied little between individuals and over time. This study provides novel insights into movement patterns and athletic performance of leopards through quantitative high-resolution measurement of the locomotor, energetic, spatial and temporal movement characteristics. The results are unbiased by methodological and observational limitations characteristic of previous studies and demonstrate the utility of applying new technologies to field studies of elusive nocturnal species
Indoor Air Quality in Elderly Centers: Pollutants Emission and Health Effects
The world population is ageing, in particular in the developed world, with a significant increase in the percentage of people above 60 years old. They represent a segment of the population that is more vulnerable to adverse environmental conditions. Among them, indoor air quality is one of the most relevant, as elders spend comparatively more time indoors than younger generations. Furthermore, the recent COVID-19 pandemic contributed immensely to raising awareness of the importance of breathing air quality for human health and of the fact that indoor air is a vector for airborne infections and poisoning. Hence, this work reviews the state of the art regarding indoor air quality in elderly centers, considering the type of pollutants involved, their emission sources, and their health effects. Moreover, the influence of ventilation on air quality is also addressed. Notwithstanding the potential health problems with the corresponding costs and morbidity effects, only a few studies have considered explicitly indoor air quality and its impacts on elderly health. More studies are, therefore, necessary to objectively identify what are the impacts on the health of elderly people due to the quality of indoor air and how it can be improved, either by reducing the pollutants emission sources or by more adequate ventilation and thermal comfort strategies. © 2022 by the authors. Licensee MDPI, Basel, Switzerland.Funding: This work was financially supported by base funding of the following projects: LA/P/0045/2020 (ALiCE), UIDB/00511/2020 (LEPABE), and UIDB/50022/2020 (LAETA), funded by national funds through FCT/MCTES (PIDDAC). Fátima Felgueiras gratefully acknowledges the Portuguese National Funding Agency for Science, Research, and Technology (FCT) for the financial support through the Grant BD/6521/2020. António Martins thanks FCT for funding through program DL 57/2016—Norma transitória. Teresa Mata gratefully acknowledge the funding of Project NORTE-06-3559-FSE-000107, cofinanced by Programa Operacional Regional do Norte (NORTE2020), through Fundo Social Europeu (FSE)
Genetic Basis of Nonsyndromic Sensorineural Hearing Loss in the Sub-Saharan African Island Population of São Tomé and PrÃncipe: The Role of the DFNB1 Locus?
Hearing loss (HL) is a common condition with both genetic and environmental causes, and it greatly impacts global health. The prevalence of HL is reportedly higher in developing countries such as the Sub-Saharan African island of São Tomé and PrÃncipe, where the deaf community is estimated to be less than 1% of the population. We investigated the role of the DFNB1 locus (GJB2 and GJB6 genes) in the etiology of nonsyndromic sensorineural hearing loss (NSSHL) in São Tomé and PrÃncipe. A sample of 316 individuals, comprising 136 NSSHL patients (92 bilateral, 44 unilateral) and 180 controls, underwent a clinical and audiological examination. Sequencing of the GJB2 coding region and testing for the (GJB6-D13S1830) and del(GJB6-D13S1854) GJB6 deletions were performed. A total of 311 out of 316 individuals were successfully analyzed regarding the GJB2 and GJB6 genetic variations, respectively. The frequency of the GJB2 coding mutations in patients and controls was low. Some of those coding mutations are the most commonly found in Eurasian and Mediterranean populations and have also been identified in Portugal. None of the GJB6 deletions was present. The presence of certain coding variants in São Tomé and PrÃncipe suggests a non-Sub-Saharan genetic influx and supports the previously reported genetic influx from European (mainly Portuguese) ancestors. In summary, DFNB1 locus does not appear to be a major contributor to NSSHL in São Tomé and PrÃncipe. However, the presence of both pathogenic and likely pathogenic mutations in GJB2 suggests that GJB2-related NSSHL might still occur in this population, warranting further research on GJB2 testing in NSSHL cases
Behavioural stress responses predict environmental perception in European sea bass (Dicentrarchus labrax)
Individual variation in the response to environmental challenges depends partly on innate reaction norms, partly on experience-based cognitive/emotional evaluations that individuals make of the situation. The goal of this study was to investigate whether pre-existing differences in behaviour predict the outcome of such assessment of environmental cues, using a conditioned place preference/avoidance (CPP/CPA) paradigm. A comparative vertebrate model (European sea bass, Dicentrarchus labrax) was used, and ninety juvenile individuals were initially screened for behavioural reactivity using a net restraining test. Thereafter each individual was tested in a choice tank using net chasing as aversive stimulus or exposure to familiar conspecifics as appetitive stimulus in the preferred or non preferred side respectively (called hereafter stimulation side). Locomotor behaviour (i.e. time spent, distance travelled and swimming speed in each tank side) of each individual was recorded and analysed with video software. The results showed that fish which were previously exposed to appetitive stimulus increased significantly the time spent on the stimulation side, while aversive stimulus led to a strong decrease in time spent on the stimulation side. Moreover, this study showed clearly that proactive fish were characterised by a stronger preference for the social stimulus and when placed in a putative aversive environment showed a lower physiological stress responses than reactive fish. In conclusion, this study showed for the first time in sea bass, that the CPP/CPA paradigm can be used to assess the valence (positive vs. negative) that fish attribute to different stimuli and that individual behavioural traits is predictive of how stimuli are perceived and thus of the magnitude of preference or avoidance behaviour.European Commission [265957]; Portuguese Fundacao para a Ciencia e Tecnologia (FCT) [FRH/BPD/72952/2010]; FCT [SFRH/BD/80029/2011
Male Uro-Rectal Iatrogenic Fistula Treatment in Pelvic Tumours: A National Multi-Institutional Study
Introdução: As fÃstulas uro-rectais (FUR) constituem uma complicação devastadora do tratamento de tumores pélvicos e um desafio cirúrgico para o cirurgião reconstrutivo. Contudo, apesar da sua crescente incidência associada a uma utilização cada vez mais frequente das diferentes modalidades não-cirúrgicas, especialmente de radioterapia, com ou sem cirurgia, para o tratamento de tumores pélvicos, a fÃstula urorectal permanece relativamente rara. Dada a elevada improbabilidade do encerramento espontâneo da fÃstula uro-rectal, a correcção cirúrgica torna-se necessária na quase totalidade dos casos. Apesar da existência de várias técnicas cirúrgicas, as taxas de falência/recorrência são habitualmente elevadas, particularmente em fÃstulas rádicas. Descrevemos neste estudo a nossa experiência limitada no tratamento de fÃstulas urorectais resultantes de tratamentos de tumores pélvicos (aparelho urinário inferior e recto).
Métodos: Entre Outubro de 2008 e Fevereiro de 2015, foram identificados 12 pacientes do sexo masculino com fÃstula urorectal e tratados nas nossas instituições. Foi efectuada revisão dos processos clÃnicos dos pacientes, incluindo a idade, sintomas, presença de comorbilidades, marcha diagnóstica, tipo e
etiologia da fÃstula, tipo de reconstrução cirúrgica, follow-up e resultados. Foram excluÃdos do estudo todos os pacientes com fÃstula não-neoplásica/inflamatória.
Resultados: Foram identificados e tratados 12 pacientes nas nossas instituições. Um dos pacientes, após ressecção anterior do recto, desenvolveu metástases ganglionares e hepáticas 4 meses após o diagnóstico da fÃstula urorectal, durante tratamento médico/antibiótico de abcesso pélvico e sua resolução após drenagem e, consequentemente, foi excluÃdo do tratamento cirúrgico e do estudo. A idade média dos doentes era de 68 anos (53 – 78). Nove pacientes desenvolveram fÃstula uro-rectal após terapêutica de carcinoma da próstata): Dois após braquiterapia de baixa dosagem combinada com radioterapia externa; cinco após prostatectomia radical retropúbica (PRR), com radioterapia externa adjuvante em um; um após braquiterapia de baixa dosagem seguida de ressecção transuretral por obstrução prostática; e um após ultra-som focalizado de alta intensidade e radioterapia externa. Em dois pacientes, a fÃstula resultou de tratamento cirúrgico de carcinoma rectal, associado a radioterapia externa em um deles. Foi efectuada em todos os pacientes derivação fecal com colostomia e derivação urinária, ou com cateterização suprapúbica, ou com cateterização uretral durante o perÃodo de espera para a reconstrução cirúrgica. Não houve encerramento espontâneo de fÃstula urorectal em nenhum paciente. Onze pacientes foram submetidos a reconstrução cirúrgica. Foi utilizada
abordagem exclusivamente perineal em sete doentes e abdominoperineal em quatro. Obteve-se encerramento eficaz da fÃstula em seis pacientes à primeira tentativa cirúrgica, dois doentes necessitaram
uma segunda tentativa, enquanto que em um doente foram necessárias três tentativas cirúrgicas (duas delas em outras instituições) de forma a atingir um resultado com sucesso. Ocorreu falência cirúrgica em dois doentes, os quais, actualmente, não desejam qualquer tentativa reconstrutiva adicional. Estes dois doentes e um doente, em quem a reconstrução foi eficaz, permanecem ainda com colostomia. O tempo médio de follow-
-up foi de 25,5 meses (3-75).
Conclusão: As fÃstulas uro-rectais são uma complicação pouco frequente, mas devastadora, do tratamento dos tumores pélvicos, habitualmente associada com morbilidade debilitante e degradação da qualidade de vida. Embora a sua reconstrução cirúrgica possa ser extremamente difÃcil, ela é possÃvel com sucesso na maioria dos casos através de uma abordagem perineal ou abdominoperineal agressiva e interposição de tecidos, quando indicada.info:eu-repo/semantics/publishedVersio
Silicon-based spin and charge quantum computation
Silicon-based quantum-computer architectures have attracted attention because
of their promise for scalability and their potential for synergetically
utilizing the available resources associated with the existing Si technology
infrastructure. Electronic and nuclear spins of shallow donors (e.g.
phosphorus) in Si are ideal candidates for qubits in such proposals due to the
relatively long spin coherence times. For these spin qubits, donor electron
charge manipulation by external gates is a key ingredient for control and
read-out of single-qubit operations, while shallow donor exchange gates are
frequently invoked to perform two-qubit operations. More recently, charge
qubits based on tunnel coupling in P substitutional molecular ions in Si
have also been proposed. We discuss the feasibility of the building blocks
involved in shallow donor quantum computation in silicon, taking into account
the peculiarities of silicon electronic structure, in particular the six
degenerate states at the conduction band edge. We show that quantum
interference among these states does not significantly affect operations
involving a single donor, but leads to fast oscillations in electron exchange
coupling and on tunnel-coupling strength when the donor pair relative position
is changed on a lattice-parameter scale. These studies illustrate the
considerable potential as well as the tremendous challenges posed by donor spin
and charge as candidates for qubits in silicon.Comment: Review paper (invited) - to appear in Annals of the Brazilian Academy
of Science
Alterações nos parâmetros fisiológicos dos recém-nascidos sob oxigenoterapia na coleta de gasometria
Synchronous bursts on scale-free neuronal networks with attractive and repulsive coupling
This paper investigates the dependence of synchronization transitions of
bursting oscillations on the information transmission delay over scale-free
neuronal networks with attractive and repulsive coupling. It is shown that for
both types of coupling, the delay always plays a subtle role in either
promoting or impairing synchronization. In particular, depending on the
inherent oscillation period of individual neurons, regions of irregular and
regular propagating excitatory fronts appear intermittently as the delay
increases. These delay-induced synchronization transitions are manifested as
well-expressed minima in the measure for spatiotemporal synchrony. For
attractive coupling, the minima appear at every integer multiple of the average
oscillation period, while for the repulsive coupling, they appear at every odd
multiple of the half of the average oscillation period. The obtained results
are robust to the variations of the dynamics of individual neurons, the system
size, and the neuronal firing type. Hence, they can be used to characterize
attractively or repulsively coupled scale-free neuronal networks with delays.Comment: 15 pages, 9 figures; accepted for publication in PLoS ONE [related
work available at http://arxiv.org/abs/0907.4961 and
http://www.matjazperc.com/
Aurora kinase A drives the evolution of resistance to third-generation EGFR inhibitors in lung cancer.
Although targeted therapies often elicit profound initial patient responses, these effects are transient due to residual disease leading to acquired resistance. How tumors transition between drug responsiveness, tolerance and resistance, especially in the absence of preexisting subclones, remains unclear. In epidermal growth factor receptor (EGFR)-mutant lung adenocarcinoma cells, we demonstrate that residual disease and acquired resistance in response to EGFR inhibitors requires Aurora kinase A (AURKA) activity. Nongenetic resistance through the activation of AURKA by its coactivator TPX2 emerges in response to chronic EGFR inhibition where it mitigates drug-induced apoptosis. Aurora kinase inhibitors suppress this adaptive survival program, increasing the magnitude and duration of EGFR inhibitor response in preclinical models. Treatment-induced activation of AURKA is associated with resistance to EGFR inhibitors in vitro, in vivo and in most individuals with EGFR-mutant lung adenocarcinoma. These findings delineate a molecular path whereby drug resistance emerges from drug-tolerant cells and unveils a synthetic lethal strategy for enhancing responses to EGFR inhibitors by suppressing AURKA-driven residual disease and acquired resistance
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