Magnetic behaviour of multisegmented FeCoCu/Cu electrodeposited nanowires

Understanding the magnetic behaviour of multisegmented nanowires (NWs) is a major key for the application of such structures in future devices. In this work, magnetic/non-magnetic arrays of FeCoCu/Cu multilayered NWs electrodeposited in nanoporous alumina templates are studied. Contrarily to most reports on multilayered NWs, the magnetic layer thickness was kept constant (30 nm) and only the non-magnetic layer thickness was changed (0 to 80 nm). This allowed us to tune the interwire and intrawire interactions between the magnetic layers in the NW array creating a three-dimensional (3D) magnetic system without the need to change the template characteristics. Magnetic hysteresis loops, measured with the applied field parallel and perpendicular to the NWs' long axis, showed the effect of the non-magnetic Cu layer on the overall magnetic properties of the NW arrays. In particular, introducing Cu layers along the magnetic NW axis creates domain wall nucleation sites that facilitate the magnetization reversal of the wires, as seen by the decrease in the parallel coercivity and the reduction of the perpendicular saturation field. By further increasing the Cu layer thickness, the interactions between the magnetic segments, both along the NW axis and of neighbouring NWs, decrease, thus rising again the parallel coercivity and the perpendicular saturation field. This work shows how one can easily tune the parallel and perpendicular magnetic properties of a 3D magnetic layer system by adjusting the non-magnetic layer thickness

Estudio empírico sobre la influencia de recursos heurísticos en la resolución de problemas de probabilidad condicionada L0 y L2

Se ha constatado la dificultad de los estudiantes a la hora de resolver problemas de probabilidad condicionada (Cañadas et al., 2011). En general, la complejidad de estos problemas es debida a varios factores: el formato y el orden en el que se presentan los datos, el contexto en el que se plantea el problema, el lenguaje utilizado para expresar los datos condicionales o las herramientas utilizadas en el proceso de resolución. En nuestro estudio nos centraremos en el uso y la influencia de recursos heurísticos, como tablas de contingencia o diagramas de árbol, durante la resolución de un problema de probabilidad condicionada

Microestructura del esmalte de los incisivos de roedores (Mammalia, Rodentia)

Abstract not availabl

All-fiber tunable optical delay line

We present a tunable optical delay line based on the use of a single chirped fiber Bragg grating written into a standard single mode optical fiber. In the proposed scheme, the delay is induced through the Bragg grating differential group delay curve. This is achieved by launching orthogonally polarized optical pulses in both directions into the Bragg grating and by controlling its local birefringence. This bidirectional propagation allows to compensate the second-order dispersion. The setup is suitable to delay pulses with a spectral width just less than the grating reflection bandwidth, which is particularly useful in the context of forthcoming wavelength division multiplexing ultra-high bit rate lightwave systems. In this work, the performances of the setup are investigated using a pulsed laser delivering 6.3 ps Fourier transform limited pulses at 1548 nm. A maximum delay of 120 ps (about 20 times the pulse width) is reported experimentally

Fertilization capacity with rainbow trout DNA-damaged sperm and embryo developmental success

Mammalian spermatozoa undergo a strong selection process along the female tract to guarantee fertilization by good quality cells, but risks of fertilization with DNA-damaged spermatozoa have been reported. In contrast, most external fertilizers such as fish seem to have weaker selection procedures. This fact, together with their high prolificacy and external embryo development, indicates that fish could be useful for the study of the effects of sperm DNA damage on embryo development. We cryopreserved sperm from rainbow trout using egg yolk and low-density lipoprotein as additives to promote different rates of DNA damage. DNA fragmentation and oxidization were analyzed using comet assay with and without digestion with restriction enzymes, and fertilization trials were performed. Some embryo batches were treated with 3-aminobenzamide (3AB) to inhibit DNA repair by the poly (ADP-ribose) polymerase, which is an enzyme of the base excision repair pathway. Results showed that all the spermatozoa cryopreserved with egg yolk carried more than 10% fragmented DNA, maintaining fertilization rates of 61.1+/-2.3 but a high rate of abortions, especially during gastrulation, and only 14.5+/-4.4 hatching success. Furthermore, after 3AB treatment, hatching dropped to 3.2+/-2.2, showing that at least 10% DNA fragmentation was repaired. We conclude that trout sperm maintains its ability to fertilize in spite of having DNA damage, but that embryo survival is affected. Damage is partially repaired by the oocyte during the first cleavage. Important advantages of using rainbow trout for the study of processes related to DNA damage and repair during development have been reported. Reproduction (2010) 139 989-997Junta de Castilla y Leon (Spain) [LE007A06]; University of Leoninfo:eu-repo/semantics/publishedVersio

Improved time-resolved acousto-optic technique for optical fiber analysis of axial non-uniformities by using edge interrogation

The time-resolved acousto-optic technique demonstrated recently to be a very useful method for the analysis of fiber axial non-uniformities, able to detect variations of fiber diameter in the nanometric scale with a spatial resolution of few cm. An edge interrogation approach is proposed to improve further the performance of this technique. The detection of subnanometer fiber diameter changes or sub-ppm changes of the core refractive index is demonstrated

Two isoforms of vasa maternal factor in Senegalese sole: Biotechnological applications

Primordial Germ Cells (PGCs) identification and manipulation present considerable potential for hatchery practice and surrogate broodstocks. To carry out the PGCs characterization a specific molecular marker is required. The vasa gene is a good candidate to identify PGCs and others germinal cells (Nagasawa et al., 2009). The aim of this study was the cloning of the Solea senegalensis vasa cDNA and its expression pattern during early development and adulthood

Brillouin optical time-domain analysis over a 240 km-long fiber loop with no repeater

22nd International Conference on Optical Fiber Sensors (OFS2012), Beijing, China, October 14, 2012In this paper we combine the use of optical pulse coding and seeded second-order Raman amplification to extend the\ud sensing distance of Brillouin optical time-domain analysis (BOTDA) sensors. Using 255-bit Simplex coding, the power\ud levels of the Raman pumps and the Brillouin pump and probe signals were adjusted in order to extend the real physical\ud sensing distance of a BOTDA sensor up to 120 km away from the sensor interrogation unit, employing a 240-km long\ud loop of standard single-mode fiber (SSMF) with no repeater. To the best of our knowledge, this is the first time that\ud distributed measurements are carried out over such a long distance with no active device inserted into the entire sensing\ud loop, constituting a considerable breakthrough in the field

Biochemistry Instructors’ Views toward Developing and Assessing Visual Literacy in Their Courses

Biochemistry instructors are inundated with various representations from which to choose to depict biochemical phenomena. Because of the immense amount of visual know-how needed to be an expert biochemist in the 21st century, there have been calls for instructors to develop biochemistry students’ visual literacy. However, visual literacy has multiple aspects, and determining which area to develop can be quite daunting. Therefore, the goals of this study were to determine what visual literacy skills biochemistry instructors deem to be most important and how instructors develop and assess visual literacy skills in their biochemistry courses. In order to address these goals, a needs assessment was administered to a national sample of biochemistry faculty at four-year colleges and universities. Based on the results of the survey, a cluster analysis was conducted to group instructors into categories based on how they intended to develop visual literacy in their courses. A misalignment was found between the visual literacy skills that were most important and how instructors developed visual literacy. In addition, the majority of instructors assumed these skills on assessments rather than explicitly testing them. Implications focus on the need for better measures to assess visual literacy skills directly

Genetic insights into the social organization of Neanderthals

Genomic analyses of Neanderthals have previously provided insights into their population history and relationship to modern humans1–8, but the social organization of Neanderthal communities remains poorly understood. Here we present genetic data for 13 Neanderthals from two Middle Palaeolithic sites in the Altai Mountains of southern Siberia: 11 from Chagyrskaya Cave9,10 and 2 from Okladnikov Cave11—making this one of the largest genetic studies of a Neanderthal population to date. We used hybridization capture to obtain genome-wide nuclear data, as well as mitochondrial and Y-chromosome sequences. Some Chagyrskaya individuals were closely related, including a father–daughter pair and a pair of second-degree relatives, indicating that at least some of the individuals lived at the same time. Up to one-third of these individuals’ genomes had long segments of homozygosity, suggesting that the Chagyrskaya Neanderthals were part of a small community. In addition, the Y-chromosome diversity is an order of magnitude lower than the mitochondrial diversity, a pattern that we found is best explained by female migration between communities. Thus, the genetic data presented here provide a detailed documentation of the social organization of an isolated Neanderthal community at the easternmost extent of their known range