2,857 research outputs found
Investigation and modeling of viscoelastic moduli for multilayered polymeric systems using high frequency ultrasonic waves
Mechanical characterization of both the bulk and individual layer properties of layered polymer stacks provides important information for their use in novel applications. A single technique to measure both the bulk and layer properties is atempted. Ultrasonic testing provides an opportunity to determine the mechanical characteristics for layered samples in the form of the complex mechanical moduli. These moduli express the viscoelastic properties of the materials. Using ultrasound, this can be done for the bulk and the layers in a single test. With ultrasound, the ability to determine the complex moduli in single layers has been demonstrated. The moduli were determined within the expected range. The ultrasonic testing has also allowed the determination of the speed of sound of the individual layers in a 2 layer sample consisting of layers of Polycarbonate and Poly(methyl methacrylate). Internal interference limited the ability to measure attenuation. To attempt to allow for analysis of these complex waveforms, a secondary technique for waveform analysis has been proposed and developed. This method employs a finite element simulation to replicate the experiment. By deriving a simulation with the complex moduli as inputs, it is possible to use the simulation results to measure the moduli of multilayered samples. This is done comparatively through iteration of the simulation inputs. When a set of inputs creates a simulated result matching the experimental scans, a solution has been found. A preliminary version of the simulation is presented and demonstrated
Clustering in Cell Cycle Dynamics with General Response/Signaling Feedback
Motivated by experimental and theoretical work on autonomous oscillations in
yeast, we analyze ordinary differential equations models of large populations
of cells with cell-cycle dependent feedback. We assume a particular type of
feedback that we call Responsive/Signaling (RS), but do not specify a
functional form of the feedback. We study the dynamics and emergent behaviour
of solutions, particularly temporal clustering and stability of clustered
solutions. We establish the existence of certain periodic clustered solutions
as well as "uniform" solutions and add to the evidence that cell-cycle
dependent feedback robustly leads to cell-cycle clustering. We highlight the
fundamental differences in dynamics between systems with negative and positive
feedback. For positive feedback systems the most important mechanism seems to
be the stability of individual isolated clusters. On the other hand we find
that in negative feedback systems, clusters must interact with each other to
reinforce coherence. We conclude from various details of the mathematical
analysis that negative feedback is most consistent with observations in yeast
experiments.Comment: To appear in J. Theoretical Biology 292 (2012), 103-11
Development of Entrepreneurial Attitudes Assessment Instrument for Freshman Students
An increasing population of university programs and quantity of curricular content focused on entrepreneurship poses both enormous opportunities for student growth, and numerous practical challenges. Prior work has largely focused on pre-post assessment of student learning, shifts in‘mindset’, activity effectiveness, mapping of student outcomes, and implications of student learning on career success. A baseline of freshman student attitudes towards entrepreneurship,outside of specifically focused entrepreneurial leaning, has significant potential to identify and inform programming in entrepreneurship, as well as general curriculums and pedagogy. An improved understanding of student’s constructive and cognitive influences in entrepreneurial education will serve to better inform the way entrepreneurship education in engineering is historically and currently discussed. Improving entrepreneurship education models begins with understanding student backgrounds comprised of different experiences, knowledge, and preconceptions. When looking longitudinally, migratory information can better inform entrepreneurial programming to provide data and support for more organized and integrated approaches to entrepreneurship education.This work in progress provides initial results and validation on the quantitative instrument portion of a mixed methods study developed for assessing and tracking entrepreneurial behaviors, experiences, and attitudes in a way identifiable to engineering and business freshman.The instrument is modified from the Entrepreneurial Attitude Orientation (EAO) survey instrument developed by Robbins in the early 1990s. Additionally, a section for gathering student socioeconomic status and gender, using elements of the Academic Pathways of People Learning Engineering Survey (APPLES) is included. Based on the difficulties in operationalization of student socioeconomic status self-identification, normalizing question are added as suggested by Donaldson and Sheppard from results in the APPLES instrument development process.The quantitative portion, discussed here, survey will be deployed during winter of 2015, to business and engineering freshman at a large Midwestern university. The initial deployment will allow validation against prior uses of the EAO instrument. Results will be presented in the paper and conference presentation comparing gender and socioeconomic correlations to entrepreneurial attitudes with previous publications. The survey instrument is being developed as the quantitative element of a mixed method longitudinal study tracking student entrepreneurial attitudes, focus, and growth over student college experiences. Follow-on efforts are intended to help better inform educators about the nature of student construction and growth in an university space increasingly influenced by a move towards entrepreneurship education
More Comprehensive and Inclusive Approaches to Demographic Data Collection
In this evidence-based practice paper, we discuss ways for researchers and educators to more sensitively, accurately, and effectively collect demographic information on surveys. Identifying variables that capture diversity more broadly is vital in understanding the variety of ways in which students participate in and experiencing engineering education. We frame this discussion through publically available statistics that suggest the potential error in common approaches employed for demographic collection. While basic questions about participants’ sex and ethnicity are standard items in assessment and data collection, these questions only develop a limited representation and potentially present an inaccurate accounting of students’ social identities and honest self-expression. Classic demographic measurement approaches classify students on broad, general, and historically driven elements of diversity typically defined by others rather than individual students. Unfortunately, simply asking a participant to self-identify their gender dichotomously or select from a pre-defined set of ethnicity options has the potential to record information that does not completely or accurately represent a student’s self-identified characteristics or a researchers latent purpose. Alternatively, asking questions via simple open-ended queries both maintains any problem represented in the phrasing of the question as well as presents a major loss in efficiency by requiring a post-collection coding step. In this paper we discuss three major topics through reviews of literature, emergent cultural norms, and suggestions for better practices. First, we will cover the framing of demographic questions to gather the intended information (i.e., differentiating how the student experiences the world and how the world experiences the student). Second, we address ordering of demographic questions and the extended capability provided by modern online collection tools. Finally, using the lessons of parts one and two we offer some examples of improved ways of collecting a variety of demographic information such as gender identity, ethnicity, language, sexual orientation, disability status, and socioeconomic status. The examples will show how researchers can be more sensitive to issues of diversity while at the same time improving research quality
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Achimota Pararubulavirus 3: A New Bat-Derived Paramyxovirus of the Genus Pararubulavirus
Bats are an important source of viral zoonoses, including paramyxoviruses. The paramyxoviral Pararubulavirus genus contains viruses mostly derived from bats that are common, diverse, distributed throughout the Old World, and known to be zoonotic. Here, we describe a new member of the genus Achimota pararubulavirus 3 (AchPV3) and its isolation from the urine of African straw-coloured fruit bats on primary bat kidneys cells. We sequenced and analysed the genome of AchPV3 relative to other Paramyxoviridae, revealing it to be similar to known pararubulaviruses. Phylogenetic analysis of AchPV3 revealed the failure of molecular detection in the urine sample from which AchPV3 was derived and an attachment protein most closely related with AchPV2—a pararubulavirus known to cause cross-species transmission. Together these findings add to the picture of pararubulaviruses, their sources, and variable zoonotic potential, which is key to our understanding of host restriction and spillover of bat-derived paramyxoviruses. AchPV3 represents a novel candidate zoonosis and an important tool for further study
Bootstrapping Multilingual AMR with Contextual Word Alignments
We develop high performance multilingualAbstract Meaning Representation (AMR)
sys-tems by projecting English AMR annotationsto other languages with weak
supervision. Weachieve this goal by bootstrapping transformer-based
multilingual word embeddings, in partic-ular those from cross-lingual RoBERTa
(XLM-R large). We develop a novel technique forforeign-text-to-English AMR
alignment, usingthe contextual word alignment between En-glish and foreign
language tokens. This wordalignment is weakly supervised and relies onthe
contextualized XLM-R word embeddings.We achieve a highly competitive
performancethat surpasses the best published results forGerman, Italian,
Spanish and Chinese
Individual differences in zoo-housed squirrel monkeys’ (<i>Saimiri sciureus</i>) reactions to visitors, research participation, and personality ratings
Understanding individual differences in captive squirrel monkeys is a topic of importance both for improving welfare by catering to individual needs, and for better understanding the results and implications of behavioral research. In this study, 23 squirrel monkeys (Saimiri sciureus), housed in an environment that is both a zoo enclosure and research facility, were assessed for (i) the time they spent by an observation window under three visitor conditions: no visitors, small groups, and large groups, and (ii) their likelihood of participating in voluntary research, and (iii) zookeepers ratings of personality. A Friedman’s ANOVA and Wilcoxon post-hoc tests comparing mean times found that the monkeys spent more time by the window when there were large groups present than when there were small groups or no visitors. Thus, visitors do not seem to have a negative effect and may be enriching for certain individuals. Through GLMM and correlational analyses, it was found that high scores on the personality trait of playfulness and low scores on cautiousness, depression, and solitude were significant predictors of increased window approach behavior when visitors were present. The GLMM and correlational analyses assessing the links between personality traits and research participation found that low scores of cautiousness and high scores of playfulness, gentleness, affection, and friendliness, were significant predictors. The implications of these results are discussed in relation to selection bias and its potential confounding effect on cognitive studies with voluntary participation
Mate choice confers direct benefits to females of Anastrepha fraterculus (Diptera: Tephritidae)
Exposure to plant compounds and analogues of juvenile hormone (JH) increase male mating success in several species of tephritid fruit flies. Most of these species exhibit a lek mating system, characterized by active female choice. Although the pattern of enhanced male mating success is evident, few studies have investigated what benefits, if any, females gain via choice of exposed males in the lek mating system. In the South American fruit fly, Anastrepha fraterculus, females mate preferentially with males that were exposed to volatiles released by guava fruit or treated with methoprene (a JH analogue). Here, we tested the hypothesis that female choice confers direct fitness benefits in terms of fecundity and fertility. We first carried out mate choice experiments presenting females with males treated and non-treated with guava volatiles or, alternatively, treated and non-treated with methoprene. After we confirmed female preference for treated males, we compared the fecundity and fertility between females mated with treated males and non-treated ones. We found that A. fraterculus females that mated with males exposed to guava volatiles showed higher fecundity than females mated to non-exposed males. On the other hand, females that mated methoprene-treated males showed no evidence of direct benefits. Our findings represent the first evidence of a direct benefit associated to female preference for males that were exposed to host fruit odors in tephritid fruit flies. Differences between the two treatments are discussed in evolutionary and pest management terms.Fil: Bachmann, Guillermo Enrique. Instituto Nacional de Tecnologia Agropecuaria. Centro de Investigacion En Ciencias Veterinarias y Agronomicas. Instituto de Agrobiotecnologia y Biologia Molecular. Grupo Vinculado Instituto de Genetica "ewald A. Favret" Al Iabimo | Consejo Nacional de Investigaciones Cientificas y Tecnicas. Oficina de Coordinacion Administrativa Pque. Centenario. Instituto de Agrobiotecnologia y Biologia Molecular. Grupo Vinculado Instituto de Genetica "ewald A. Favret" Al Iabimo.; ArgentinaFil: Devescovi, Francisco. Instituto Nacional de Tecnologia Agropecuaria. Centro de Investigacion En Ciencias Veterinarias y Agronomicas. Instituto de Agrobiotecnologia y Biologia Molecular. Grupo Vinculado Instituto de Genetica "ewald A. Favret" Al Iabimo | Consejo Nacional de Investigaciones Cientificas y Tecnicas. Oficina de Coordinacion Administrativa Pque. Centenario. Instituto de Agrobiotecnologia y Biologia Molecular. Grupo Vinculado Instituto de Genetica "ewald A. Favret" Al Iabimo.; ArgentinaFil: Nussenbaum, Ana Laura. Instituto Nacional de Tecnologia Agropecuaria. Centro de Investigacion En Ciencias Veterinarias y Agronomicas. Instituto de Agrobiotecnologia y Biologia Molecular. Grupo Vinculado Instituto de Genetica "ewald A. Favret" Al Iabimo | Consejo Nacional de Investigaciones Cientificas y Tecnicas. Oficina de Coordinacion Administrativa Pque. Centenario. Instituto de Agrobiotecnologia y Biologia Molecular. Grupo Vinculado Instituto de Genetica "ewald A. Favret" Al Iabimo.; ArgentinaFil: Milla, Fabian Horacio. Instituto Nacional de Tecnologia Agropecuaria. Centro de Investigacion En Ciencias Veterinarias y Agronomicas. Instituto de Agrobiotecnologia y Biologia Molecular. Grupo Vinculado Instituto de Genetica "ewald A. Favret" Al Iabimo | Consejo Nacional de Investigaciones Cientificas y Tecnicas. Oficina de Coordinacion Administrativa Pque. Centenario. Instituto de Agrobiotecnologia y Biologia Molecular. Grupo Vinculado Instituto de Genetica "ewald A. Favret" Al Iabimo.; ArgentinaFil: Shelly, Todd E.. Animal and Plant Health Inspection Service; Estados UnidosFil: Cladera, Jorge Luis. Instituto Nacional de Tecnologia Agropecuaria. Centro de Investigacion En Ciencias Veterinarias y Agronomicas. Instituto de Agrobiotecnologia y Biologia Molecular. Grupo Vinculado Instituto de Genetica "ewald A. Favret" Al Iabimo | Consejo Nacional de Investigaciones Cientificas y Tecnicas. Oficina de Coordinacion Administrativa Pque. Centenario. Instituto de Agrobiotecnologia y Biologia Molecular. Grupo Vinculado Instituto de Genetica "ewald A. Favret" Al Iabimo.; ArgentinaFil: Fernandez, Patricia Carina. Instituto Nacional de TecnologÃa Agropecuaria. Centro Regional Buenos Aires Norte. Estación Experimental Agropecuaria Delta del Paraná; Argentina. Consejo Nacional de Investigaciones CientÃficas y Técnicas; ArgentinaFil: Vera, MarÃa Teresa. Universidad Nacional de Tucumán. Facultad de AgronomÃa y Zootecnia; Argentina. Consejo Nacional de Investigaciones CientÃficas y Técnicas; ArgentinaFil: Segura, Diego Fernando. Instituto Nacional de Tecnologia Agropecuaria. Centro de Investigacion En Ciencias Veterinarias y Agronomicas. Instituto de Agrobiotecnologia y Biologia Molecular. Grupo Vinculado Instituto de Genetica "ewald A. Favret" Al Iabimo | Consejo Nacional de Investigaciones Cientificas y Tecnicas. Oficina de Coordinacion Administrativa Pque. Centenario. Instituto de Agrobiotecnologia y Biologia Molecular. Grupo Vinculado Instituto de Genetica "ewald A. Favret" Al Iabimo.; Argentin
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