3,692 research outputs found
Magnetization switching and domain-wall propagation behavior in edge-modulated ferromagnetic nanowire structures
Tuning magnon spectra via interlayer coupling in pseudo-3D nanostructured artificial spin ice arrays
We have investigated the static and dynamic behavior of “pseudo-3D” trilayer square artificial spin ice structures. The trilayer stack comprises of two ferromagnetic Ni81Fe19 (Permalloy, Py) layers with 30 and 70 nm thickness, separated by a nonmagnetic copper layer of varying thickness from 2 to 40 nm. We show that the copper thickness enables interlayer coupling between layers to be finely controlled, leading to bespoke magnetization states and resonance spectra tuning. Our results demonstrate a further route to control the interaction in artificial spin ices beyond planar structures, enabling tunable magnetization dynamics, a potentially programmable degree of freedom for magnonic and microwave devices
Nanometric constrictions in superconducting coplanar waveguide resonators
We report on the design, fabrication and characterization of superconducting
coplanar waveguide resonators with nanoscopic constrictions. By reducing the
size of the center line down to 50 nm, the radio frequency currents are
concentrated and the magnetic field in its vicinity is increased. The device
characteristics are only slightly modified by the constrictions, with changes
in resonance frequency lower than 1% and internal quality factors of the same
order of magnitude as the original ones. These devices could enable the
achievement of higher couplings to small magnetic samples or even to single
molecular spins and have applications in circuit quantum electrodynamics,
quantum computing and electron paramagnetic resonance.Comment: 4 pages, 4 figure
The Three Dimensional Thirring Model for Small N_f
We formulate the three dimensional Thirring model on a spacetime lattice and
study it for various even numbers of fermion flavors N_f by Monte Carlo
simulation. We find clear evidence for spontaneous chiral symmetry breaking at
strong coupling, contradicting the predictions of the 1/N_f expansion. The
critical point appears to correspond to an ultra-violet fixed point of the
renormalisation group; a fit to a RG-inspired equation of state in the vicinity
of the fixed point yields distinct critical exponents for N_f=2 and N_f=4,
while no fit is found for N_f=6, suggesting there is a critical number N_fc<6
beyond which no chiral symmetry breaking occurs. The spectrum of the N_f=2
theory is studied; the states examined vary sharply but continuously across the
transition.Comment: 50 pages LaTeX, including 16 tables and 20 figures - uses style file
ldd_art.sty (included
First record of the globally-threatened Cerrado endemic snake <i>Philodryas livida</i> (Amaral, 1923) (Serpentes, Dipsadidae) from Paraguay, and the importance of the Reserva Natural Laguna Blanca to its conservation
Paraguay. Reserva Natural Laguna Blanca (RNLB), Departamento San Pedro. (23º46’52.6”S, 56º17’28.9”W). RNLB is a 804 hectare reserve consisting of over 400 hectares of near pristine Cerrado, a patch of degraded Atlantic Forest, and areas of transitional semi-deciduous, semi-humid gallery forest. The four main Cerrado ecotopes are present at RNLB and grow on a predominately sandy substrate (Eiten, 1972; 1978). The reserve is based around an eponymously-named freshwater lake of 157 hectares which, geologically-speaking, is possibly the only true lake in Paraguay (Guyra Paraguay, 2008).Asociación Herpetológica Argentina (AHA
First record of the globally-threatened Cerrado endemic snake <i>Philodryas livida</i> (Amaral, 1923) (Serpentes, Dipsadidae) from Paraguay, and the importance of the Reserva Natural Laguna Blanca to its conservation
Paraguay. Reserva Natural Laguna Blanca (RNLB), Departamento San Pedro. (23º46’52.6”S, 56º17’28.9”W). RNLB is a 804 hectare reserve consisting of over 400 hectares of near pristine Cerrado, a patch of degraded Atlantic Forest, and areas of transitional semi-deciduous, semi-humid gallery forest. The four main Cerrado ecotopes are present at RNLB and grow on a predominately sandy substrate (Eiten, 1972; 1978). The reserve is based around an eponymously-named freshwater lake of 157 hectares which, geologically-speaking, is possibly the only true lake in Paraguay (Guyra Paraguay, 2008).Asociación Herpetológica Argentina (AHA
Adjuvant Therapy of Nivolumab Combined With Ipilimumab Versus Nivolumab Alone in Patients With Resected Stage IIIB-D or Stage IV Melanoma (CheckMate 915)
Teràpia adjuvant; MelanomaTerapia adyuvante; MelanomaAdjuvant therapy; MelanomaPURPOSE
Ipilimumab and nivolumab have each shown treatment benefit for high-risk resected melanoma. The phase III CheckMate 915 trial evaluated adjuvant nivolumab plus ipilimumab versus nivolumab alone in patients with resected stage IIIB-D or IV melanoma.
PATIENTS AND METHODS
In this randomized, double-blind, phase III trial, 1,833 patients received nivolumab 240 mg once every 2 weeks plus ipilimumab 1 mg/kg once every 6 weeks (916 patients) or nivolumab 480 mg once every 4 weeks (917 patients) for ≤ 1 year. After random assignment, patients were stratified by tumor programmed death ligand 1 (PD-L1) expression and stage. Dual primary end points were recurrence-free survival (RFS) in randomly assigned patients and in the tumor PD-L1 expression-level < 1% subgroup.
RESULTS
At a minimum follow-up of approximately 23.7 months, there was no significant difference between treatment groups for RFS in the all-randomly assigned patient population (hazard ratio, 0.92; 95% CI, 0.77 to 1.09; P = .269) or in patients with PD-L1 expression < 1% (hazard ratio, 0.91; 95% CI, 0.73 to 1.14). In all patients, 24-month RFS rates were 64.6% (combination) and 63.2% (nivolumab). Treatment-related grade 3 or 4 adverse events were reported in 32.6% of patients in the combination group and 12.8% in the nivolumab group. Treatment-related deaths were reported in 0.4% of patients in the combination group and in no nivolumab-treated patients.
CONCLUSION
Nivolumab 240 mg once every 2 weeks plus ipilimumab 1 mg/kg once every 6 weeks did not improve RFS versus nivolumab 480 mg once every 4 weeks in patients with stage IIIB-D or stage IV melanoma. Nivolumab showed efficacy consistent with previous adjuvant studies in a population resembling current practice using American Joint Committee on Cancer eighth edition, reaffirming nivolumab as a standard of care for melanoma adjuvant treatment
Assessment of the structural integrity of the Roman bridge of Alcántara (Spain) using TLS and GPR
El puente romano de Alcántara es el más grande de España. Su preservación es de suma importancia y para ello deben estudiarse diferentes aspectos. El más destacado es la evaluación de su estructura, y esto es especialmente importante ya que el puente permanece en uso. Este documento documenta la forma en que se llevó a cabo la evaluación de la seguridad estructural. Se aplicó la metodología de evaluación de las estructuras existentes. La evaluación preliminar se basó en datos bibliográficos y técnicas no destructivas. Los datos geométricos del puente se obtuvieron mediante el escaneado láser terrestre (TLS), que permitió el análisis de sus deformaciones y la evaluación de su estructura. También se utilizó el Radar de penetración en el suelo (GPR) con diferentes antenas para trabajar a diferentes profundidades y resoluciones espaciales con el fin de analizar los elementos estructurales. A partir de la información anterior, la evaluación de la seguridad estructural se realizó mediante el método de análisis de límites aplicando los trabajos históricos realizados sobre el mismo y los descritos en la normativa de obligado cumplimiento en España (IAP11), estudiando la sensibilidad de la seguridad a los parámetros más relevantes. Se discute el estado de conservación e integridad estructural del puente y se extraen conclusiones sobre las áreas de mayor riesgo y las bases para la siguiente fase de evaluación de la conservación del puente.The Roman bridge of Alcántara is the largest in Spain. Its preservation is of the utmost importance and to this end different aspects must be studied. The most prominent is the assessment of its structure, and this is especially important as the bridge remains in use. This paper documents the way the assessment of structural safety was carried out. The assessment methodology of existing structures was applied. The preliminary assessment was based on bibliographic data and non-destructive techniques. The geometric data of the bridge were obtained by Terrestrial Laser Scanning (TLS), which made possible the analysis of its deformations and assessment of its structure. Ground-Penetrating Radar (GPR) was also used with different antennae to work at different depths and spatial resolutions with the aim of analysing structural elements. From the above information, the assessment of structural safety was made using the limit analysis method by applying the historical works carried out on it and those described in the regulation of obligatory compliance in Spain (IAP11), studying the sensitivity of safety to the most relevant parameters. The state of preservation and structural integrity of the bridge is discussed and conclusions are drawn on the areas of greatest risk and the bases for the following assessment phase of preservation of the bridge.• Junta de Extremadura y Fondos FEDER. Ayuda GR15069 y GR15107, para el grupo de investigación NEXUS y COMPHASpeerReviewe
Timing molecular motion and production with a synthetic transcriptional clock
The realization of artificial biochemical reaction networks with unique functionality is one of the main challenges for the development of synthetic biology. Due to the reduced number of components, biochemical circuits constructed in vitro promise to be more amenable to systematic design and quantitative assessment than circuits embedded within living organisms. To make good on that promise, effective methods for composing subsystems into larger systems are needed. Here we used an artificial biochemical oscillator based on in vitro transcription and RNA degradation reactions to drive a variety of “load” processes such as the operation of a DNA-based nanomechanical device (“DNA tweezers”) or the production of a functional RNA molecule (an aptamer for malachite green). We implemented several mechanisms for coupling the load processes to the oscillator circuit and compared them based on how much the load affected the frequency and amplitude of the core oscillator, and how much of the load was effectively driven. Based on heuristic insights and computational modeling, an “insulator circuit” was developed, which strongly reduced the detrimental influence of the load on the oscillator circuit. Understanding how to design effective insulation between biochemical subsystems will be critical for the synthesis of larger and more complex systems
Suppression of Walker breakdown in magnetic domain wall propagation through structural control of spin wave emission
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