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1.
Rev Sci Instrum ; 95(6)2024 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-38921059

RESUMO

Superconducting magnets based on Rare Earth Barium Copper Oxides (REBCO) offer transformative capabilities in the fields of fusion energy, high energy physics, and space exploration. A challenge shared by these applications is the limited lifetime of REBCO due to radiation damage sustained during operation. Here we present a new ion-beam facility that enables simultaneous cryogenic irradiation and in situ characterization of commercial REBCO tapes. The ion source provides spatially uniform fluxes up to 1018 protons/m2s with kinetic energies up to 3.4 MeV, in addition to helium and higher-Z species. Using this facility, we can induce uniform damage profiles in the first 10-20 µm of REBCO tapes with less than 0.25 appm of hydrogen implanted in REBCO after a dose of 1020 protons/m2. The tape can be held between 20 and 300 K with an accuracy of ±0.1 K and is connected to a four-point probe measuring the critical current, Ic, and critical temperature, Tc, before, during, and after irradiation with transport current ranging from 100 nA to 100 A, and a typical voltage noise less than 0.1 µV. These capabilities are presently used to study the effect of irradiation temperature on REBCO performance change during and after proton bombardment, to assess the possibility of Ic and Tc recovery after irradiation through thermal annealing, and to explore the instantaneous and recoverable suppression of Ic and Tc observed during irradiation.

3.
Sociol Ruralis ; 64(2): 180-201, 2024 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-38680761

RESUMO

This paper focuses on the relationships between people and farmed nonhuman animals, and between these animals and the farmed environments they encounter, in the enactment of interspecies endemic disease situations. It examines how the nonhuman embodied capacities, agency and subjectivities of cows and sheep on farms in the north of England make a difference to how the endemic conditions of lameness and bovine viral diarrhoea (BVD) are encountered and responded to by farmers and advisers. The paper draws on empirical research with farmers and their advisers, and explores three key, inter-related, themes: first, the importance of intersubjective relationships between people and animals on farms; second, the nonhuman components of the 'disease situations' associated with endemic diseases, including animals' embodied characteristics and behaviours and the relationships between bodies and environments on different farms; and finally the ways in which animal agency and resistance makes a difference to on-farm interventions aiming to prevent or treat lameness and BVD. The paper concludes by arguing that animals' capacities, and nonhuman difference, should be taken further into account in future policy and practice interventions in endemic disease in farmed animals.

4.
Nature ; 620(7973): 299-302, 2023 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-37558847

RESUMO

The presence of perennially wet surface environments on early Mars is well documented1,2, but little is known about short-term episodicity in the early hydroclimate3. Post-depositional processes driven by such short-term fluctuations may produce distinct structures, yet these are rarely preserved in the sedimentary record4. Incomplete geological constraints have led global models of the early Mars water cycle and climate to produce diverging results5,6. Here we report observations by the Curiosity rover at Gale Crater indicating that high-frequency wet-dry cycling occurred in early Martian surface environments. We observe exhumed centimetric polygonal ridges with sulfate enrichments, joined at Y-junctions, that record cracks formed in fresh mud owing to repeated wet-dry cycles of regular intensity. Instead of sporadic hydrological activity induced by impacts or volcanoes5, our findings point to a sustained, cyclic, possibly seasonal, climate on early Mars. Furthermore, as wet-dry cycling can promote prebiotic polymerization7,8, the Gale evaporitic basin may have been particularly conducive to these processes. The observed polygonal patterns are physically and temporally associated with the transition from smectite clays to sulfate-bearing strata, a globally distributed mineral transition1. This indicates that the Noachian-Hesperian transition (3.8-3.6 billion years ago) may have sustained an Earth-like climate regime and surface environments favourable to prebiotic evolution.


Assuntos
Meio Ambiente Extraterreno , Marte , Ciclo Hidrológico , Água , Argila/química , Meio Ambiente Extraterreno/química , Minerais/análise , Minerais/química , Sulfatos/análise , Sulfatos/química , Umidade , Água/análise , Origem da Vida , Exobiologia
5.
Vet J ; 298-299: 106019, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37536451

RESUMO

Field tests and their association with laminitis have not been evaluated in large cohorts. The objectives of this study were to evaluate the performance of basal insulin (BI), the oral sugar test (OST) and the insulin tolerance test (ITT) to diagnose ID and investigate their association with laminitis. Insulin dysregulation status was determined in 146 ponies using BI (insulin concentration >20 µIU/mL), an OST (insulin concentration >65 µIU/mL at 60 or 90 min after oral administration of 0.45 mL/kg corn syrup) and an ITT (< 50% reduction in glucose concentration 30 min after intravenous administration of 0.1 IU/kg insulin). Laminitis was identified using modified-Obel scores. A Bayesian approach was used to define the characteristics of the tests and receiver operating characteristic curves were used to assess their association with laminitis. All tests were well tolerated and laminitis was diagnosed in 9% of ponies. Insulin dysregulation was diagnosed in 15% of ponies using BI, 38% using the OST and 54% using the ITT with 11% of ponies positive for all three tests. The sensitivities and specificities of BI, the OST and the ITT to diagnose ID were 0.52 (95% confidence interval [CI], 0.35-0.79) and 0.97 (95% CI, 0.91 - 1.00), 0.84 (95% CI, 0.70 - 0.94) and 0.60 (95% CI, 0.49 - 0.71), and 0.85 (95% CI, 0.68-0.96) and 0.88 (95% CI, 0.75 - 0.97), respectively. Only BI and the OST were associated with laminitis (P = 0.003 and 0.015, respectively).


Assuntos
Doenças do Pé , Doenças dos Cavalos , Cavalos , Animais , Insulina , Glicemia , Teste de Tolerância a Glucose/veterinária , Teorema de Bayes , Administração Intravenosa/veterinária , Doenças dos Cavalos/diagnóstico , Doenças do Pé/diagnóstico , Doenças do Pé/veterinária
6.
Sci Robot ; 8(81): eadf9001, 2023 Aug 30.
Artigo em Inglês | MEDLINE | ID: mdl-37647385

RESUMO

Soft robot arms offer safety and adaptability due to their passive compliance, but this compliance typically limits their payload capacity and prevents them from performing many tasks. This paper presents a model-based design approach to effectively increase the payload capacity of soft robot arms. The proposed approach uses localized body stiffening to decrease the compliance at the end effector without sacrificing the robot's range of motion. This approach is validated on both a simulated and a real soft robot arm, where experiments show that increasing the stiffness of localized regions of their bodies reduces the compliance at the end effector and increases the height to which the arm can lift a payload. By increasing the payload capacity of soft robot arms, this approach has the potential to improve their efficacy in a variety of tasks including object manipulation and exploration of cluttered environments.

7.
bioRxiv ; 2023 Aug 21.
Artigo em Inglês | MEDLINE | ID: mdl-37577676

RESUMO

Spatial cognition research requires behavioral paradigms that can distinguish between different navigational elements, such as allocentric (map-like) navigation and egocentric (e.g., body centered) navigation. To fill this need, we developed a flexible experimental platform that can be quickly modified without the need for significant changes to software and hardware. In this paper, we present this inexpensive and flexible behavioral platform paired with software which we are making freely available. Our behavioral platform serves as the foundation for a range of experiments, and though developed for assessing spatial cognition, it also has applications in the non-spatial domain of behavioral testing. There are two components of the software platform, 'Maze' and 'Stim Trigger'. Both programs can work in conjunction with electrophysiology acquisition systems, allowing for precise time stamping of neural events with behavior. The Maze program includes functionality for automatic reward delivery based on user defined zones. 'Stim Trigger' permits control of brain stimulation via any equipment that can be paired with an Arduino board. We seek to share our software and leverage the potential by expanding functionality in the future to meet the needs of a larger community of researchers.

8.
Phys Rev Lett ; 130(24): 242501, 2023 Jun 16.
Artigo em Inglês | MEDLINE | ID: mdl-37390416

RESUMO

Excited-state spectroscopy from the first experiment at the Facility for Rare Isotope Beams (FRIB) is reported. A 24(2)-µs isomer was observed with the FRIB Decay Station initiator (FDSi) through a cascade of 224- and 401-keV γ rays in coincidence with ^{32}Na nuclei. This is the only known microsecond isomer (1 µs≤T_{1/2}<1 ms) in the region. This nucleus is at the heart of the N=20 island of shape inversion and is at the crossroads of the spherical shell-model, deformed shell-model, and ab initio theories. It can be represented as the coupling of a proton hole and neutron particle to ^{32}Mg, ^{32}Mg+π^{-1}+ν^{+1}. This odd-odd coupling and isomer formation provides a sensitive measure of the underlying shape degrees of freedom of ^{32}Mg, where the onset of spherical-to-deformed shape inversion begins with a low-lying deformed 2^{+} state at 885 keV and a low-lying shape-coexisting 0_{2}^{+} state at 1058 keV. We suggest two possible explanations for the 625-keV isomer in ^{32}Na: a 6^{-} spherical shape isomer that decays by E2 or a 0^{+} deformed spin isomer that decays by M2. The present results and calculations are most consistent with the latter, indicating that the low-lying states are dominated by deformation.


Assuntos
Núcleo Celular , Coração , Isótopos , Nêutrons
9.
Anim Cogn ; 26(3): 861-883, 2023 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-36494587

RESUMO

The nature of the representation guiding spatial navigation has been investigated extensively; however, most of this work has used behavioral tasks that involved learning the location of food reward or an escape platform. In contrast, relatively few studies have focused on the spatial representation of a home base, a ubiquitous feature of open-field behavior, and its ability to be encoded relative to environmental cues. The current set of experiments investigated acquisition and retention of the location of home base establishment. In general, proximal cues anchored the position of the home base during acquisition sessions across all four experiments. Although mice established a home base during retention sessions, previous experience did not influence its position during retention sessions. These observations demonstrate that stimulus control of home base position depends on access to proximal cues. Further work is needed to determine the extent that home base establishment may provide a framework to encode goal-directed spatial behaviors.


Assuntos
Sinais (Psicologia) , Navegação Espacial , Camundongos , Animais , Comportamento Exploratório
10.
Phys Rev Lett ; 129(21): 212501, 2022 Nov 18.
Artigo em Inglês | MEDLINE | ID: mdl-36461950

RESUMO

New half-lives for exotic isotopes approaching the neutron drip-line in the vicinity of N∼28 for Z=12-15 were measured at the Facility for Rare Isotope Beams (FRIB) with the FRIB decay station initiator. The first experimental results are compared to the latest quasiparticle random phase approximation and shell-model calculations. Overall, the measured half-lives are consistent with the available theoretical descriptions and suggest a well-developed region of deformation below ^{48}Ca in the N=28 isotones. The erosion of the Z=14 subshell closure in Si is experimentally confirmed at N=28, and a reduction in the ^{38}Mg half-life is observed as compared with its isotopic neighbors, which does not seem to be predicted well based on the decay energy and deformation trends. This highlights the need for both additional data in this very exotic region, and for more advanced theoretical efforts.

11.
Science ; 377(6614): eabo2196, 2022 09 30.
Artigo em Inglês | MEDLINE | ID: mdl-36007009

RESUMO

The Perseverance rover landed in Jezero crater, Mars, to investigate ancient lake and river deposits. We report observations of the crater floor, below the crater's sedimentary delta, finding that the floor consists of igneous rocks altered by water. The lowest exposed unit, informally named Séítah, is a coarsely crystalline olivine-rich rock, which accumulated at the base of a magma body. Magnesium-iron carbonates along grain boundaries indicate reactions with carbon dioxide-rich water under water-poor conditions. Overlying Séítah is a unit informally named Máaz, which we interpret as lava flows or the chemical complement to Séítah in a layered igneous body. Voids in these rocks contain sulfates and perchlorates, likely introduced by later near-surface brine evaporation. Core samples of these rocks have been stored aboard Perseverance for potential return to Earth.

12.
Science ; 377(6614): 1513-1519, 2022 09 30.
Artigo em Inglês | MEDLINE | ID: mdl-36007094

RESUMO

The geological units on the floor of Jezero crater, Mars, are part of a wider regional stratigraphy of olivine-rich rocks, which extends well beyond the crater. We investigated the petrology of olivine and carbonate-bearing rocks of the Séítah formation in the floor of Jezero. Using multispectral images and x-ray fluorescence data, acquired by the Perseverance rover, we performed a petrographic analysis of the Bastide and Brac outcrops within this unit. We found that these outcrops are composed of igneous rock, moderately altered by aqueous fluid. The igneous rocks are mainly made of coarse-grained olivine, similar to some martian meteorites. We interpret them as an olivine cumulate, formed by settling and enrichment of olivine through multistage cooling of a thick magma body.

13.
Science ; 377(6603): 285-291, 2022 07 15.
Artigo em Inglês | MEDLINE | ID: mdl-35857591

RESUMO

Carbonaceous asteroids, such as (101955) Bennu, preserve material from the early Solar System, including volatile compounds and organic molecules. We report spacecraft imaging and spectral data collected during and after retrieval of a sample from Bennu's surface. The sampling event mobilized rocks and dust into a debris plume, excavating a 9-meter-long elliptical crater. This exposed material is darker, spectrally redder, and more abundant in fine particulates than the original surface. The bulk density of the displaced subsurface material was 500 to 700 kilograms per cubic meter, which is about half that of the whole asteroid. Particulates that landed on instrument optics spectrally resemble aqueously altered carbonaceous meteorites. The spacecraft stored 250 ± 101 grams of material, which will be delivered to Earth in 2023.

14.
J Frailty Aging ; 11(2): 143-150, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35441190

RESUMO

Handgrip dynamometers are widely used to measure handgrip strength (HGS). HGS is a safe and easy to obtain measure of strength capacity, and a reliable assessment of muscle function. Although HGS provides robust prognostic value and utility, several protocol variants exist for HGS in clinical settings and translational research. This lack of methodological consistency could threaten the precision of HGS measurements and limit comparisons between the growing number of studies measuring HGS. Providing awareness of the protocol variants for HGS and making suggestions to reduce the implications of these variants will help to improve methodological consistency. Moreover, leveraging recent advancements in HGS equipment may enable us to use more sophisticated HGS dynamometer technologies to better assess muscle function. This Special Article will 1) highlight differences in HGS protocols and instrumentation, 2) provide recommendations to better specify HGS procedures and equipment, and 3) present future research directions for studies that measure HGS. We also provided a minimum reporting criteria framework to help future research studies avoid underreporting of HGS procedures.


Assuntos
Força da Mão , Tecnologia , Força da Mão/fisiologia , Humanos , Prognóstico , Ciência Translacional Biomédica
15.
Space Sci Rev ; 218(2): 5, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35250103

RESUMO

Two of the instruments onboard the OSIRIS-REx spacecraft, the MapCam color imager and the OVIRS visible and infrared spectrometer, observed the surface of asteroid (101955) Bennu in partially overlapping wavelengths. Significant scientific advances have been enabled by using data from these two instruments in tandem, but a robust statistical understanding of their relationship is needed for future analyses to cross-compare their data as accurately and sensitively as possible. Here we present a cross-instrument comparison of data acquired by MapCam and OVIRS, including methods and results for all global and site-specific observation campaigns in which both instruments were active. In our analysis, we consider both the absolute radiometric offset and the relative (normalized) variation between the two instruments; we find that both depend strongly on the photometric and instrumental conditions during the observation. The two instruments have a large absolute offset (>15%) due to their independent radiometric calibrations. However, they are very consistent (relative offset as low as 1%) when each instrument's response is normalized at a single wavelength, particularly at low phase angles where shadows on Bennu's rough surface are minimized. We recommend using the global datasets acquired at 12:30 pm local solar time for cross-comparisons; data acquired at higher phase angles have larger uncertainties.

16.
Int J Immunogenet ; 49(1): 22-29, 2022 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-34555264

RESUMO

All UK H&I laboratories and transplant units operate under a single national kidney offering policy, but there have been variations in approach regarding when to undertake the pre-transplant crossmatch test. In order to minimize cold ischaemia times for deceased donor kidney transplantation we sought to find ways to be able to report a crossmatch result as early as possible in the donation process. A panel of experts in transplant surgery, nephrology, specialist nursing in organ donation and H&I (all relevant UK laboratories represented) assessed evidence and opinion concerning five factors that relate to the effectiveness of the crossmatch process, as follows: when the result should be ready for reporting; what level of donor HLA typing is needed; crossmatch sample type and availability; fairness and equity; risks and patient safety. Guidelines aimed at improving practice based on these issues are presented, and we expect that following these will allow H&I laboratories to contribute to reducing CIT in deceased donor kidney transplantation.


Assuntos
Transplante de Rim , Tipagem e Reações Cruzadas Sanguíneas , Isquemia Fria , Antígenos HLA , Teste de Histocompatibilidade , Humanos , Rim
17.
J Frailty Aging ; 10(4): 357-360, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34549251

RESUMO

This Brief Report describes a pilot study of the effect of 12 weeks of stationary bicycle high-intensity interval training, stationary bicycle moderate-intensity continuous training, and resistance training on cardiorespiratory, muscular, and physical function measures in insufficiently-active older adults (N=14; 66.4±3.9 years; 3 male, 11 female). After baseline testing, participants were randomly assigned to one of the exercise groups. High-intensity interval training and moderate-intensity continuous training had small-to-large effect sizes on cardiorespiratory/endurance and physical function measures, but very small effect sizes on muscular measures. Resistance training had small-to-large effect sizes on cardiorespiratory, muscular, and physical function measures. This pilot study should be interpreted cautiously, but findings suggest that resistance exercise may be the most effective of the three studied exercise strategies for older adults as it can induce beneficial adaptations across multiple domains. These effect sizes can be used to determine optimal sample sizes for future investigations.


Assuntos
Treinamento Intervalado de Alta Intensidade , Treinamento Resistido , Idoso , Exercício Físico , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Músculo Esquelético , Projetos Piloto
18.
Ann Clin Biochem ; 58(4): 305-310, 2021 07.
Artigo em Inglês | MEDLINE | ID: mdl-33554608

RESUMO

BACKGROUND: Accurate and rapid testing for SARS-COV-2 antibodies could improve the diagnosis and management of COVID-19. In this study, we aim to evaluate the diagnostic accuracy of a commercially available point-of-care lateral flow kit independently and in comparison to an established platform-based system. METHOD: Samples from 144 PCR-confirmed COVID-19 cases and 130 pre-pandemic negative controls were tested in parallel by MP Rapid 2019-NCOV IgM/IgG Combo test and Roche Elecsys. Comparison of results based on serum and capillary blood testing was undertaken. RESULTS: Sensitivity at day 15 onwards was 100% for both methods. Between days 1 and 7 post admission, the IgM/IgG Combo test and Roche Elecsys shown sensitivity of 74% (95%CI: 62%-85%) vs. 67% (95% CI: 55%-79%, P = 0.3947). Combo test specificities were 100% for IgG, 98.5% for IgM vs. Roche Elecsys specificity of 100%. Concordance analysis showed 98.5% agreement to the Roche Elecsys method (Cohen's Kappa 0.96 95% CI [0.92-0.99]). Capillary blood results showed complete agreement with serum samples using the Combo test. CONCLUSION: In comparison to Roche Elecsys, our data show that the MP Rapid 2019-NCOV IgM/IgG Combo test provides a high-confidence assay system for the detection of previous exposure to SARS-COV-2 infection with advantage of affording near-patient testing.


Assuntos
Anticorpos Antivirais/sangue , Teste Sorológico para COVID-19 , COVID-19/sangue , Imunoglobulina G/sangue , Imunoglobulina M/sangue , Sistemas Automatizados de Assistência Junto ao Leito , SARS-CoV-2/metabolismo , Humanos , Sensibilidade e Especificidade
19.
Med Vet Entomol ; 35(3): 231-238, 2021 09.
Artigo em Inglês | MEDLINE | ID: mdl-33480060

RESUMO

Onchocerciasis is a neglected tropical disease (NTD) caused by Onchocerca Diesing 1841 (Spirurida: Onchocercidae) nematodes transmitted by blackflies. It is associated with poverty and imposes a significant health, welfare and economic burden on many tropical countries. Current methods to visualize infections within the vectors rely on invasive methods. However, using micro-computed tomography techniques, without interference from physical tissue manipulation, we visualized in three dimensions for the first time an L1 larva of an Onchocerca species within the thoracic musculature of a blackfly, Simulium damnosum s.l. Theobald 1903 (Diptera: Simuliidae), naturally infected in Ghana. The possibility that thicker peritrophic membranes in savannah flies could account for their lower parasite loads was not supported, but there were limits to our analysis. While there were no statistically significant differences between the mean thicknesses of the peritrophic membranes, in the anterior, dorsal and ventral regions, of forest and savannah blackflies killed 34-48 min after a blood-meal, the thickness of the peritrophic membrane in the posterior region could not be measured. Micro-computed tomography has the potential to provide novel information on many other parasite/vector systems and impactful images for public engagement in health education.


Assuntos
Oncocercose , Simuliidae , Animais , Florestas , Insetos Vetores , Onchocerca , Oncocercose/veterinária , Microtomografia por Raio-X
20.
Med Vet Entomol ; 35(1): 106-120, 2021 03.
Artigo em Inglês | MEDLINE | ID: mdl-32896916

RESUMO

Oestrid flies (Diptera: Oestridae) do not feed during the adult stage, so they depend on an efficient assimilation and storage of nutrients during their parasitic larval stage. We describe the general morphology and provide volumetric data for the digestive and excretory organs of the three larval instars of the nasal bot fly Oestrus ovis L., using micro-computed tomography. The size of the digestive and excretory organs greatly increased across larval instars. In all instars, the two salivary glands were remarkably large and formed a 'glandular band' by coming together, but without lumina uniting, at their posterior ends. The distal region of the anterior Malpighian tubules was greatly enlarged and full of highly radio-opaque concretions. Moreover, the anatomy of O. ovis third-instar larva was compared to that of two species of, respectively, similar and different feeding habits: Cephenemyia stimulator (Clark) and Hypoderma actaeon Brauer. Whereas the general morphology and arrangement of the digestive and excretory systems of C. stimulator was similar to that of O. ovis, some differences were observed in H. actaeon: a swollen anterior region of the midgut, salivary glands shorter and not forming a 'band' and anterior Malpighian tubules narrowly uniform throughout their entire length.


Assuntos
Dípteros/anatomia & histologia , Túbulos de Malpighi/anatomia & histologia , Animais , Sistema Digestório/anatomia & histologia , Sistema Digestório/crescimento & desenvolvimento , Dípteros/crescimento & desenvolvimento , Larva/anatomia & histologia , Larva/crescimento & desenvolvimento , Túbulos de Malpighi/crescimento & desenvolvimento , Especificidade da Espécie , Microtomografia por Raio-X
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