Showing papers by "Albion College published in 2010"

Twin Nucleation by Slip Transfer across Grain Boundaries in Commercial Purity Titanium

Abstract: The role of strain transfer in the activation of deformation twinning at grain boundaries has been characterized in commercially pure titanium deformed in bending. Two different orientations of a textured polycrystal were deformed in bending and were analyzed using electron backscattered diffraction (EBSD) to determine the active slip and twinning systems in the surface tensile region. Prismatic slip and $$ \left\{ {10\bar{1}2} \right\}\left\langle {\bar{1}011} \right\rangle $$ twinning were the most widely observed deformation modes in both orientations. Nonprismatic slip systems were also activated, most likely to accommodate local strain heterogeneities. A slip-stimulated twin nucleation mechanism was identified for soft/hard grain pairs: dislocation slip in a soft-oriented grain can stimulate twin nucleation in the neighboring hard grain when the slip system is well aligned with the twinning system. This alignment was described by a slip-transfer parameter m′.[24] Twins activated by this mechanism always had the highest m′ value among the six available $$ \left\{ {10\bar{1}2} \right\}\left\langle {\bar{1}011} \right\rangle $$ twinning systems, while the Schmid factor, based on the global (uniaxial tensile) stress state, was a less significant indicator of twin activity. Through slip transfer, deformation twins sometimes formed despite having a very low global Schmid factor. The frequency of slip-stimulated twin nucleation depends strongly on the texture and loading direction in the material. For grain pairs having one grain with a large Schmid factor for twinning, nonparametric statistical analysis confirms that those with a larger m′ are more likely to display slip-stimulated twinning.

Generation of optical coherent-state superpositions by number-resolved photon subtraction from the squeezed vacuum

Abstract: We have created heralded coherent-state superpositions (CSSs) by subtracting up to three photons from a pulse of squeezed vacuum light. To produce such CSSs at a sufficient rate, we used our high-efficiency photon-number-resolving transition edge sensor to detect the subtracted photons. This experiment is enabled by and utilizes the full photon-number-resolving capabilities of this detector. The CSS produced by three-photon subtraction had a mean-photon number of $2.{75}_{\ensuremath{-}0.24}^{+0.06}$ and a fidelity of $0.{59}_{\ensuremath{-}0.14}^{+0.04}$ with an ideal CSS. This confirms that subtracting more photons results in higher-amplitude CSSs.

Developmental networks and learning: toward an interdisciplinary perspective on identity development during doctoral study

Abstract: The authors draw on two families of theories – developmental networks and sociocultural perspectives on learning – to develop an interdisciplinary approach to the study of doctoral education as a path to the professoriate. This approach seeks to elucidate the connection between doctoral students’ developmental networks, what they learn during their graduate experience (including their learning about the faculty role) and how they develop a professional identity. The authors first discuss the key tenets of the developmental networks and sociocultural perspectives, before exploring their alignments and explaining how the combination might remedy the limitations inherent in each approach. Finally, they offer some research propositions and directions for further study of the preparation of doctoral students for academic careers.

The genomics education partnership: successful integration of research into laboratory classes at a diverse group of undergraduate institutions.

Abstract: Genomics is not only essential for students to understand biology but also provides unprecedented opportunities for undergraduate research. The goal of the Genomics Education Partnership (GEP), a collaboration between a growing number of colleges and universities around the country and the Department of Biology and Genome Center of Washington University in St. Louis, is to provide such research opportunities. Using a versatile curriculum that has been adapted to many different class settings, GEP undergraduates undertake projects to bring draft-quality genomic sequence up to high quality and/or participate in the annotation of these sequences. GEP undergraduates have improved more than 2 million bases of draft genomic sequence from several species of Drosophila and have produced hundreds of gene models using evidence-based manual annotation. Students appreciate their ability to make a contribution to ongoing research, and report increased independence and a more active learning approach after participation in GEP projects. They show knowledge gains on pre- and postcourse quizzes about genes and genomes and in bioinformatic analysis. Participating faculty also report professional gains, increased access to genomics-related technology, and an overall positive experience. We have found that using a genomics research project as the core of a laboratory course is rewarding for both faculty and students.

Beyond mentoring and advising: Toward understanding the role of faculty “developers” in student success

Abstract: It is old news that interactions between students and faculty enhance student learning. In this article, Vicki Baker and Kimberly Griffin offer another role for faculty in their relationships with students—that of developer.

The Role of Social Cognition in the Religious Fundamentalism‐Prejudice Relationship

Abstract: The study examines the indirect effects of religious fundamentalism on prejudice through cognitive style and fear of invalidity. Undergraduates (n= 199) completed measures of religious fundamentalism, homophobia, modern racism, hostile and benevolent sexism, need for cognition, need for structure, preference for consistency, and fear of invalidity. Need for cognition partially mediated the relationship between religious fundamentalism and both homophobia and benevolent sexism. Preference for consistency partially mediated the relationship between religious fundamentalism and hostile sexism. The indirect effect of religious fundamentalism on modern racism through preference for consistency approached statistical significance. The interaction between need for structure and fear of invalidity partially mediated the relationship between religious fundamentalism and both homophobia and hostile sexism, with individuals high in need for structure and low in fear of invalidity having higher religious fundamentalism and prejudice.

Superconducting Transition-Edge Sensors Optimized for High-Efficiency Photon-Number Resolving Detectors

Abstract: Superconducting photon detectors have emerged as a powerful new option for detecting single photons. System detection efficiency that incorporates the quantum efficiency of the device and system losses is one of the most important single-photon detector performance metrics for quantum information applications. Superconducting transition-edge sensors (TESs) are microcalorimeters that have the ability of distinguishing single photons with negligible dark counts. In addition, TESs are capable of directly measuring the photon number in a pulse of light. We have achieved near-unity system detection efficiency with TESs at particular wavelengths in the near-infrared by using multilayer structures that enhance the absorption of light into the active device material. We describe the design of the multilayer structure enabling high detection efficiency TESs including issues and requirements for obtaining detection efficiency values higher than 99 %. We describe the device fabrication and finally, show recent results of devices optimized for high detection efficiency using the multilayer structure.

Social change at the Harappan settlement of Gola Dhoro: a reading from animal bones

Abstract: Detailed analysis of the animal bone assemblage at Gola Dhoro here throws light on the expansion of the Indus civilisation into Gujarat. A square fort, imposed on a settlement of livestock herders in the later third millennium BC, was shown to have contained people who introduced a broader diet of meat and seafood, and new ways of preparing it. These social and dietary changes were coincident with a surge in craft and trade.

Expressed sequence tags from cephalic chemosensory organs of the northern walnut husk fly, Rhagoletis suavis, including a putative canonical odorant receptor.

Abstract: Rhagoletis fruit flies are important both as major agricultural pests and as model organisms for the study of adaptation to new host plants and host race formation. Response to fruit odor plays a critical role in such adaptation. To better understand olfaction in Rhagoletis, an expressed sequence tag (EST) study was carried out on the antennae and maxillary palps of Rhagoletis suavis (Loew) (Diptera: Tephritidae), a common pest of walnuts in eastern United States. After cDNA cloning and sequencing, 544 ESTs were annotated. Of these, 66% had an open reading frame and could be matched to a previously sequenced gene. Based on BLAST sequence homology, 9% (49 of 544 sequences) were nuclear genes potentially involved in olfaction. The most significant finding is a putative odorant receptor (OR), RSOr1, that is homologous to Drosophila melanogaster Or49a and Or85f. This is the first tephritid OR discovered that might recognize a specific odorant. Other olfactory genes recovered included odorant binding proteins, chemosensory proteins, and putative odorant degrading enzymes.

Late Miocene submarine volcanism in ANDRILL AND-1B drill core, Ross Embayment, Antarctica

Abstract: The ANDRILL McMurdo Ice Shelf initiative recovered a 1285-m-long core (AND-1B) composed of cyclic glacimarine sediments with interbedded volcanic deposits. The thickest continuous volcanic sequence by far is ∼175 m long and is found at mid-core depths from 584.19 to 759.32 m below seafloor. The sequence was logged, and initial interpretations of lithostratigraphic subdivisions were made on ice during drilling in late 2006. Subsequent observations, based on image, petrographic, and scanning electron microscopy–energy dispersive spectroscopy analyses, provide a more detailed, revised interpretation of a thick submarine to emergent volcanic succession. The sequence is subdivided into two main subsequences on the basis of sediment composition, texture, and alteration style. The ∼70-m-thick lower subsequence consists mostly of monothematic stacked volcanic-rich mudstone and sandstone deposits, which are attributed to epiclastic gravity flow turbidite processes. This subsequence is consistent with abundant active volcanism that occurred at a distal site with respect to the drill site. The ∼105-m-thick upper subsequence consists mainly of interbedded tuff, lapilli tuff, and volcanic diamictite. A Late Miocene (6.48 Ma) 2.81-m-thick subaqueously emplaced lava flow occurs within the second subsequence. This second subsequence is attributed to recurring cycles of submarine to emergent volcanic activity that occurred proximal to the drill site. This new data set provides (1) the first rock evidence of significant Late Miocene submarine volcanic activity in the Ross Embayment during a period of no to limited glaciation, and (2) a rich stratigraphic record that elucidates submarine volcano-sedimentary processes in an offshore setting.

Induction of Cellular Growth by the Axon Guidance Regulators Netrin A and Semaphorin-1a

Abstract: Although neurite outgrowth has been linked to axon guidance regulators, the effects of guidance molecules on cellular growth are not well understood. Use of the Drosophila wing imaginal disc, an epithelial tissue and a well-characterized system for analysis of cellular growth regulation, permits analysis of the impacts of guidance molecules on cellular growth in a setting in which axon guidance is not a confounding factor. In this investigation, the impacts of Netrin A (NetA) and Semaphorin-1a (Sema1a) signaling on cellular growth are examined during wing development. Levels of these genes were modulated in somatic clones in the developing wing disc, and clone areas, as well as individual sizes of clonal cells were assessed. NetA and Sema1a signaling were found to induce cellular growth in these assays. Furthermore, immunohistochemical analyses indicated that NetA and Sema1a signaling induce expression of several growth regulators, including myc, cycD, cdk4, PCNA, and MapK in the wing disc. These data illustrate that NetA and Sema1a can specifically promote growth through induction of key cellular growth regulators. The abilities of NetA and Sema1a to regulate cellular growth are likely critical to their functions in both nervous system development and oncogenesis.

Molecular analyses of the diversity in marine bacterioplankton assemblages along the coastline of the northeastern Gulf of Mexico.

Abstract: Bacterial community diversity in marine bacterioplankton assemblages were examined in 3 coastal locations along the northeastern Gulf of Mexico (GOM) using 16S rRNA gene libraries and fluorescence ...

Comparison of Fecal Indicator Bacterial Populations in Surface Waters of the Kalamazoo River, USA

Abstract: Surface waters along the Kalamazoo River, USA, were examined for occurrence and population trends of fecal indicator bacteria (FIB) with culture-based and culture-independent methods. The two methods recorded discrepancies in FIB counts, with the culture-independent method revealing more consistent numbers between the river sites. FIB cells that hybridized with the ECO1482 probe were highest in the downstream site, while the upstream site recorded higher ENF343 hybridized cells. Spatial and temporal differences in FIB populations were probably attributable to contrasting fecal pollution influences, vegetation type, varying environmental conditions as well as several in-stream factors between the two river sites.

Sexual Politics and Ascriptive Autonomy

Abstract: I explore the notion of ascriptive autonomy as a conceptual and political tool that can be used to understand and enact potentially liberatory practices that enable marginalized people to have greater individual autonomy. “Ascriptive autonomy” refers to the sense in which autonomy is partly constituted by the conferral of the status of “autonomous individual.” Autonomy is both a capacity to determine one's own ends and a status conferred by virtue of being recognized by others. I focus on the link between these two facets of autonomy insofar as recognition may enable the development of capacity. In certain situations, autonomy may be ascribed even if one lacks some requirements associated with the capacity for autonomy because of either institutional or psychic constraints that follow from oppression. In such instances of “selective, purposeful misrecognition,” ascription may lead to the cultivatation of the capacity for autonomy while opening up a space for politics. To demonstrate this, I recast the feminist debate over sexuality using the terms of ascriptive autonomy. When viewed through the lens of misrecognition, we can better respond to critiques that charge proponents of the “pro-sex”position with focusing on sexual pleasure at the expense of sufficient attention paid to the constraints faced by women.

Clean, Green Chiral Reactions—Just Add a Salt

Abstract: Chirality—literally handedness—refers to the mirror-image, or left-right asymmetry of objects like shoes and gloves. Like our hands, many chemical compounds (and most biomolecules) exist as enantiomers, which, relative to each other, have mirror-image arrangements of substituents around an atom (typically carbon or nitrogen). In many cases, pharmaceuticals must have a specific chirality in order to be active, but making pure chiral compounds is difficult and costly. Traditionally, chemists have relied on reagents for controlling chirality that contain heavy metals ( 1 ), the presence of which can lead to toxicity issues. A relatively new alternative is the use of nonmetal catalysts called organocatalysts. On page 1376 of this issue, Uyanik et al. ( 2 ) report a more “green” organocatalytic reaction that also uses an iodine reagent to closes rings in a molecule during an oxidation step.

Intra-specific niche partitioning obscures the importance of fine-scale habitat data in species distribution models

Abstract: Geographic information systems (GIS) allow researchers to make cost-effective, spatially explicit predictions of species’ distributions across broad geographic areas. However, there has been little research on whether using fine-scale habitat data collected in the field could produce more robust models of species’ distributions. Here we used radio-telemetry data collected on a declining species, the North American wood turtle (Glyptemys insculpta), to test whether fine-scale habitat variables were better predictors of occurrence than land-cover and topography variables measured in a GIS. Patterns of male and female occurrence were similar in the spring; however, females used a much wider array of land-cover types and topographic positions in the summer and early fall, making it difficult for GIS-based models to accurately predict female occurrence at this time of year. Males on the other hand consistently selected flat, low-elevation, riparian areas throughout the year, and this consistency in turn led to the development of a strong GIS-based model. These results demonstrate the importance of taking a more sex-specific and temporally dynamic view of the environmental niche.

The progress of the betting in a baseball game

Abstract: The development of the Internet has led to the creation of countless new markets, among them, online, in-game betting markets for sporting contests. We examine the behavior of prices as events unfold in a baseball game. Specifically, we compare the evolution of prices during a game with probability estimates generated by an empirical model of scoring in baseball. We find that price changes correspond closely to changes in the probability of winning, for plays of both small and dramatic impact. Nevertheless, data limitations inhibit the ability to make strong claims regarding the hypothesis of efficient pricing.

Patterns from Archimedean Tilings Using Generalized Truchet Tiles Decorated with Simple B´ ezier Curves

Abstract: Decorated tiles with simple motifs have been used to enhance the visual appeal of tilings by infusing the underlying tessellation with additional patterns. This paper explores a generalization of Truchet tiles by decorating tiles made from regular polygons with simple B´ ezier curves and considering more than one arc per side. Examples of the generalized tilings for each of the Archimedean tilings are presented using one and two arcs per side. The tension present between the global irregularity and both the local similarity and positional regularity of the generated curves provides excitement and movement not present in the underlying tessellations.

Calycogonium bairdianum (Melastomataceae: Miconieae), a new species from the Cordillera Central, Dominican Republic

Abstract: Calycogonium bairdianum, a new species, is here described from the Cordillera Central of the Dominican Republic. It is compared to C. impressum, to which it is likely related. Although Calycogonium is not monophyletic, C. bairdianum and C. impressum may be related to other species in the genus that exhibit acarodomatia formed by hairs at the two major vein junctions on the leaf abaxial surface, a likely synapomorphy. Calycogonium bairdianum is distinguished from C. impressum by its relatively glabrous (vs. pubescent) and larger leaves (i.e., usually [2.9–]4.5–8.1 cm vs. 2.1–3.7 cm long) with veins that are plane to only slightly impressed adaxially (vs. more strongly impressed).

Toward a Socially Optimal Wireless Spectrum Management

Abstract: It is widely recognized that the wireless spectrum is a scarce and limited resource and that the present practice of static spectrum allocation and exclusive licensing is inefficient. The proposed approaches generally either focus on maximization of spectrum utilization or profit maximization of individuals (such as the government or users). In this paper, we consider an efficient, or socially optimal, spectrum sharing that consists of three objectives: full (quantitative) utilization, effective (qualitative) utilization, and zero interference. Through a comparative study of these models using suggested objective criteria, we show a hybrid model consisting of a dynamic spectrum market and dynamic spectrum access supported by cognitive radio technologies that can achieve the social optimum. The dynamic spectrum market enabled by a benevolent social coordinator has fundamental differences from existing dynamic market models in that primary licensed user is not involved in the process of allocating underused spectrum. Moreover, the motivation of social coordinator is to reach socially optimal allocation of spectrum resources rather than to maximize profit or revenue of individuals.

Advanced superimposed sputtering of amorphous Indium Zinc Oxide transparent conductors for Energy applications

Abstract: In this work, we investigate the use of RF, DC, and mixed RF/DC magnetron sputtering and its effect on the optoelectronic properties of amorphous Indium Zinc Oxide (IZO) films sputtered from an 87/13 wt% ceramic target. The effect of oxygen concentration in the sputter gas is examined at several RF/DC power ratios and a variety of total powers to help optimize conductivity. We find that higher conductivities can be achieved at 50% of the typical DC sputtering oxygen concentration when duplicated via mixed RF/DC sputtering. By combining the two, mixed RF/DC sputtering allows for the high deposition rates of typical DC sputter deposition, while obtaining the greater conductivities and transparencies assisted by RF sputtering.

Taking Responsibility: PRWORA's Limits to Immigrant Access

Abstract: The 1996 welfare reforms in the US made significant changes to the eligibility criteria for immigrants to receive benefits. These reforms coincided with significant immigration reforms, tightening the requirements for legal citizenship and loosening the accountability requirements for the state in its dealing with immigrants. In this paper I suggest that the drive to limit immigrants' autonomy through welfare reform is founded on a claim that immigrants who seek out welfare have failed to "take responsibility" for the consequences of their autonomous choice to migrate. This foundational claim is deeply problematic, first because it assumes an individualistic conception of autonomy, and second because it reflects a view of immigration divorced from the reality of the economic and political interdependence of nation-states throughout the world. Immigrants' decisions to migrate can be understood as autonomous, I suggest, but only when autonomy is conceived relationally. Such decisions, where taken by emigrants from impoverished nations, must be understood as relationally constituted in part by the failure of the U.S. to take responsibility for its political and economic actions, which allow American citizens to live a comparatively privileged life at the expense of citizens of other nations. In fact, if we shift the notion of personal responsibility at the heart of the foundational claim to one of political responsibility, understood as a critical expression of autonomy, we can understand many immigrants' claims to welfare rights as forms of taking political responsibility. Such claims challenge structural conditions of inequality generated by the system of "birthright citizenship," which unequally and arbitrarily distributes benefits of citizenship status.

Remaking The Meaning of Dependence: The Case of a Supervised Injection Site

Abstract: What role can the state play in fostering autonomy in citizens who are dependent on drugs, but also deeply stigmatized, marginalized, and disenfranchised? In this paper I draw on interviews conducted with people associated with Insite, North America’s first and only supervised injection facility located in Vancouver, Canada, as well as philosophical accounts of autonomy to consider this question. At Insite, a government funded facility, injection drug users can consume pre-obtained illegal drugs under medical supervision. Fostering autonomy entails on the one hand, putting in place the relational, embodied, and material support necessary to facilitate the capacity for autonomy, the capacity to determine one’s ends or meaningfully shape one’s life plans, and on the other hand, creating the conditions wherein people are ascribed the status of an autonomous individual. In order for the state to achieve both goals where drug users and other marginalized people who are classified as dependent are concerned, it must generate institutional and social conditions that reshape the meaning of stigmatized forms of dependence. I argue that through services delivered at Insite the state is relatively successful in creating some of the institutional and material conditions for recreating the meaning of dependence on drugs (addiction) and therefore fostering autonomy. However, because of the political context in which the struggle to keep the doors of Insite open has taken place and, in turn, the ensuing public health discourse adopted by its advocates, there are limitations to the state’s ability to use Insite as a means for reconceiving dependence in such a away that it fosters the recognition-elements of autonomy. Though political expedient, the public health discourse limits recognition of autonomy in favor of recognition of “humanity,” which has different implications. This speaks more broadly to some of the limitations the state may face in attempting to foster autonomy. Nonetheless, the expanded opportunity for capacity-based autonomy that Insite offers may also provide the tools for other means of generating recognition.

Earthworms in Behavioral Neuroscience: Nearly a Century of Studies

Abstract: YERKES (1912) EXAMINED the ability of earthworms to learn a T-maze. Since then the earthworm has been a subject not only in other T-maze studies, but also in studies of Pavlovian conditioning and circadian rhythms. Its relatively simple nervous system makes the earthworm an ideal candidate for behavioral neuroscience studies; its relatively limited sensory and behavioral repertoire make such studies challenging.