Direct measurement of the phase coherence length in a GaAs/GaAlAs square network

The low temperature magnetoconductance of a large array of quantum coherentloops exhibits Altshuler-Aronov-Spivak oscillations which periodicitycorresponds to 1/2 flux quantum per loop.We show that the measurement of the harmonics content in a square networkprovides an accurate way to determine the electron phase coherence length$L\_{\phi}$ in units of the lattice length without any adjustableparameters.We use this method to determine $L\_{\phi}$ in a network realised from a 2Delectron gas (2DEG) in a GaAS/GaAlAs heterojunction. The temperaturedependence follows a power law $T^{-1/3}$ from 1.3 K to 25 mK with nosaturation, as expected for 1D diffusive electronic motion andelectron-electron scattering as the main decoherence mechanism.Comment: Additional experimental data in version

Integrating a technology-enriched curriculum: ethno-case study

The purpose of this qualitative study was to provide an examination of beliefs, context factors, and practices of exemplary teachers that lead to a technology-enriched curriculum. Three middle school teachers participated. Using both direct and participant observation the Spradley model was followed with three rounds of observations: (1) descriptive, (2) focused, and (3) selective. Interviews were conducted with open-ended questions and documents were collected from the parish website. This research provides: (1) up-to-date information on what and how educational technology is used today; and (2) information which gives other educators an understanding of what beliefs and context factors influence teachers to integrate technology into their curriculum. Findings suggest that these middle school teachers believe technology is a tool that adds value to lessons and to students\u27 learning and motivation. Due to a personal interest in technology, these teachers are self-taught and apply for grants to acquire new hardware and software. They receive support for release time to continue with ongoing professional development, which has helped to change their teaching strategies from teacher-centered to student-centered. They are not afraid to take risk using trial and error, flexible planning, project-based lessons, varying roles, varying grouping, and providing multiple activities in their classroom practices. Students are allowed to make choices, be independent, and take responsibility for themselves and their work

Propuesta de una metodología estándar para la caracterización de la organogelificación de aceites comestibles con ceras

Saturated and trans fatty acids play a significant role in the plastic properties of food. However, health recommendations suggest limiting their intake. One approach which got the attention of researchers was to decrease the amount of saturated and trans fatty acids in food by the structuring of edible oils through the crystallization of waxes. The underlying mechanisms that lead to organogelation and the properties that characterize well-structured edible oil have been slow to fully understand due in part to a lack of standardiza­tion in their analysis which often makes the comparison between research results from different laboratories difficult. The aim of this work was to review previously reported methods for the characterization of organo­gelation using vegetable and animal waxes, and to propose a minimal standardization for an organogelation analysis.Los ácidos grasos saturados y trans juegan un rol significativo en las propiedades plásticas de los alimentos. Sin embargo, las recomendaciones de salud sugieren limitar su consumo. Un enfoque que han propuesto investigadores científicos es la disminución en la cantidad de grasas trans y saturadas en la alimenta­ción por medio de la estructuración de aceites comestibles a partir de la cristalización de ceras. Los mecanismos por los cuales la organogelificación ocurre, así como las propiedades que caracterizan una buena estructuración del aceite, han sido descubiertos lentamente debido en parte a la falta de estandarización de los análisis impli­cados, lo que frecuentemente vuelve difícil la comparación entre resultados de investigación de distintos labo­ratorios. El objetivo de este trabajo es realizar una revisión de los principales métodos para la caracterización de la organogelificación y de los organogeles formados usando ceras vegetales y animales, proponiendo una estandarización mínima del análisis de organogelificación

Equivalent linear change in cognition between individuals with bipolar disorder and healthy controls over 5 years

ObjectivesCognitive dysfunction is a key feature of bipolar disorder (BD). However, not much is known about its temporal stability, as some studies have demonstrated a neurodegenerative model in BD while others have shown no change in cognitive functioning over time. Building upon our prior work, which examined the natural course of executive functioning, the current study aimed to investigate the natural course of memory, emotion processing, and fine motor dexterity over a 5‐year period in BD and healthy control (HC) samples.MethodsUsing a 5‐year longitudinal cohort, 90 individuals with BD and 17 HCs were administered a battery of neuropsychological tests at study baseline and at 1 and 5 years after study entry that captured four areas of cognitive performance: visual memory, auditory memory, emotion processing, and fine motor dexterity.ResultsLatent growth curve modeling showed no group differences in the slopes of any of the cognitive factors between the BD and HC groups. Age at baseline was negatively associated with visual memory, emotion processing, and fine motor dexterity. Education level was positively associated with auditory and visual memory and fine motor. Female gender was negatively associated with emotion processing.ConclusionsExtending our prior work on longitudinal evaluation of executive functioning, individuals with BD show similar linear change in other areas of cognitive functioning including memory, emotion processing, and fine motor dexterity as compared to unaffected HCs. Age, education, and gender may have some differential effects on cognitive changes.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/142144/1/bdi12532.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/142144/2/bdi12532_am.pd

Divergence of Arctic shrub growth associated with sea ice decline

Arctic sea ice extent (SIE) is declining at an accelerating rate with a wide range of ecological consequences. However, determining sea ice effects on tundra vegetation remains a challenge. In this study, we examined the universality or lack thereof in tundra shrub growth responses to changes in SIE and summer climate across the Pan-Arctic, taking advantage of 23 tundra shrub-ring chronologies from 19 widely distributed sites (56°N to 83°N). We show a clear divergence in shrub growth responses to SIE that began in the mid-1990s, with 39% of the chronologies showing declines and 57% showing increases in radial growth (decreasers and increasers, respectively). Structural equation models revealed that declining SIE was associated with rising air temperature and precipitation for increasers and with increasingly dry conditions for decreasers. Decreasers tended to be from areas of the Arctic with lower summer precipitation and their growth decline was related to decreases in the standardized precipitation evapotranspiration index. Our findings suggest that moisture limitation, associated with declining SIE, might inhibit the positive effects of warming on shrub growth over a considerable part of the terrestrial Arctic, thereby complicating predictions of vegetation change and future tundra productivity

Sequencing strategies for the traceability of GMOs - methods and related quality aspects

DNA sequencing in GMO analysis has undergone a rapid repositioning from a technology that may be used as an additional confirmatory step to a technique that deserves consideration as a routine methodology. The methodology may be applied in different ways, from initial screening for authorised as well as unauthorised GMOs in complex samples to, for specific cases, a strategy to establish the identity of possible new GMOs, as well as a range of options in between these two alternative applications. As the overall costs of DNA sequencing are reducing, broader applications are becoming feasible for routine testing in GMO laboratories. The actual application, however, requires further harmonisation and standardisation to maintain current quality standards when applying innovative GMO analytical strategies that include DNA sequencing steps. In the present report, a summary is provided of the results of the dedicated Working Group of the European Network of GMO Laboratories (ENGL) on good practice/quality of DNA sequencing data. The Working Group has addressed both Sanger sequencing as well as massive parallel DNA sequencing within the framework of GMO analysis, with emphasis on the latter. General information is provided in relation to quality aspects of massive parallel DNA sequencing, from sample DNA extraction and preparation, through template amplification and DNA sequencing, to quality assessment of the sequencing results and quality criteria for the use of sequencing data analysis pipelines. In addition, specific GMO-related aspects of DNA sequencing methodologies are discussed considering current GMO detection and identification strategies in different sample types (i.e. simple versus complex food/feed matrices, known versus unknown GMOs), and the intended purpose (i.e. characterisation of the full genome of a genetically modified microorganism (GMM), the full identification of an inserted genetic element and its flanking regions, or the screening for multiple genetically modified (GM) elements in a single genome or in a mixture). The Working Group identified four scenarios covering current real-life situations in GMO analysis strategies that include massive parallel DNA sequencing steps: two targeted sequencing approaches focusing on multiple known or partially known sequences, respectively, and two non-targeted sequencing approaches focusing on either whole genome sequencing of a single organism or, alternatively, applying metagenomics in complex samples. Quality considerations and criteria common to all scenarios have been tentatively established, as well as specific ones relevant for individual scenarios. On a global level, one harmonised definition of a GMO is no longer applicable, especially for genome-edited organisms that contain minor modifications, such as single nucleotide mutations. For these organisms, there is no international consensus on whether or not they should fall within the scope of the GMO regional legislations. In this context, global discussions on the safety aspects and the traceability of these organisms are affected and the exchange of information on the (potential) presence of GMO in food/feed samples and related raw materials has become hampered.JRC.F.5 - Food and Feed Complianc

Distinct Molecular Evolutionary Mechanisms Underlie the Functional Diversification of the Wnt and TGFβ Signaling Pathways

The canonical Wnt pathway is one of the oldest and most functionally diverse of animal intercellular signaling pathways. Though much is known about loss-of-function phenotypes for Wnt pathway components in several model organisms, the question of how this pathway achieved its current repertoire of functions has not been addressed. Our phylogenetic analyses of 11 multigene families from five species belonging to distinct phyla, as well as additional analyses employing the 12 Drosophila genomes, suggest frequent gene duplications affecting ligands and receptors as well as co-evolution of new ligand–receptor pairs likely facilitated the expansion of this pathway’s capabilities. Further, several examples of recent gene loss are visible in Drosophila when compared to family members in other phyla. By comparison the TGFβ signaling pathway is characterized by ancient gene duplications of ligands, receptors, and signal transducers with recent duplication events restricted to the vertebrate lineage. Overall, the data suggest that two distinct molecular evolutionary mechanisms can create a functionally diverse developmental signaling pathway. These are the recent dynamic generation of new genes and ligand–receptor interactions as seen in the Wnt pathway and the conservative adaptation of ancient pre-existing genes to new roles as seen in the TGFβ pathway. From a practical perspective, the former mechanism limits the investigator’s ability to transfer knowledge of specific pathway functions across species while the latter facilitates knowledge transfer