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Bucknell University

UniversityLewisburg, United States

Research output, citation impact, and the most-cited recent papers from Bucknell University (United States). Aggregated across the NobleBlocks index of 300M+ scholarly works.

Total works
10.6K
Citations
286.5K
h-index
187
i10-index
5.1K
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Bucknell UniversityUniversity at Lewisburg

Top-cited papers from Bucknell University

THE STAR FORMATION LAW IN NEARBY GALAXIES ON SUB-KPC SCALES
Frank Bigiel, Adam K. Leroy, Fabian Walter, E. Brinks +3 more
2008· The Astronomical Journal1.8Kdoi:10.1088/0004-6256/136/6/2846

We present a comprehensive analysis of the relationship between star formation rate surface density, SigmaSFR, and gas surface density, Sigmagas, at sub-kpc resolution in a sample of 18 nearby galaxies. We use high-resolution H I data from The H I Nearby Galaxy Survey, CO data from HERACLES and the BIMA Survey of Nearby Galaxies, 24 mum data from the Spitzer Space Telescope, and UV data from the Galaxy Evolution Explorer. We target seven spiral galaxies and 11 late-type/dwarf galaxies and investigate how the star formation law differs between the H2 dominated centers of spiral galaxies, their H I dominated outskirts and the H I rich late-type/dwarf galaxies. We find that a Schmidt-type power law with index N = 1.0 ± 0.2 relates SigmaSFR and SigmaH2 across our sample of spiral galaxies, i.e., that H2 forms stars at a constant efficiency in spirals. The average molecular gas depletion time is ~2 × 109 years. The range of SigmaH2 over which we measure this relation is ~3-50 M sun pc 2, significantly lower than in starburst environments. We find the same results when performing a pixel-by-pixel analysis, averaging in radial bins, or when varying the star formation tracer used. We interpret the linear relation and constant depletion time as evidence that stars are forming in giant molecular clouds with approximately uniform properties and that SigmaH2 may be more a measure of the filling fraction of giant molecular clouds than changing conditions in the molecular gas. The relationship between total gas surface density (Sigmagas) and SigmaSFR varies dramatically among and within spiral galaxies. Most galaxies show little or no correlation between SigmaHI and SigmaSFR. As a result, the star formation efficiency (SFE), SigmaSFR/Sigmagas, varies strongly across our sample and within individual galaxies. We show that this variation is systematic and consistent with the SFE being set by local environmental factors: in spirals the SFE is a clear function of radius, while the dwarf galaxies in our sample display SFEs similar to those found in the outer optical disks of the spirals. We attribute the similarity to common environments (low density, low metallicity, H I dominated) and argue that shear (which is typically absent in dwarfs) cannot drive the SFE. In addition to a molecular Schmidt law, the other general feature of our sample is a sharp saturation of H I surface densities at SigmaHI ≈ 9 M sun pc 2 in both the spiral and dwarf galaxies. In the case of the spirals, we observe gas in excess of this limit to be molecular.

The Role of Corporations in Achieving Ecological Sustainability
Paul Shrivastava
1995· Academy of Management Review1.4Kdoi:10.5465/amr.1995.9512280026

Ecological problems rooted in organizational activities have increased significantly, yet the role corporations play in achieving ecological sustainability is poorly understood. This article examines the implications of ecologically sustainable development for corporations. It articulates corporate ecological sustainability through the concepts of (a) total quality environmental management, (b) ecologically sustainable competitive strategies, (c) technology transfer through technology-for nature-swaps, and (d) reducing the impact of populations on ecosystems. It examines the implications that these concepts have for organizational research.

THINGS: THE H I NEARBY GALAXY SURVEY
Fabian Walter, E. Brinks, W. J. G. de Blok, Frank Bigiel +3 more
2008· The Astronomical Journal1.4Kdoi:10.1088/0004-6256/136/6/2563

We present "The HI Nearby Galaxy Survey (THINGS)", a high spectral (<=5.2 km/s) and spatial (~6") resolution survey of HI emission in 34 nearby galaxies obtained using the NRAO Very Large Array (VLA). The overarching scientific goal of THINGS is to investigate fundamental characteristics of the interstellar medium (ISM) related to galaxy morphology, star formation and mass distribution across the Hubble sequence. Unique characteristics of the THINGS database are the homogeneous sensitivity as well as spatial and velocity resolution of the HI data which is at the limit of what can be achieved with the VLA for a significant number of galaxies. A sample of 34 objects at distances 2<D<15Mpc (resulting in linear resolutions of ~100 to 500pc) are targeted in THINGS, covering a wide range of star formation rates (10^-3 to 6 M_sun/yr), total HI masses M_HI (0.01 to 14x10^9 M_sun), absolute luminosities M_B (-11.5 to -21.7 mag) and metallicities (7.5 to 9.2 in units of 12+log[O/H]). We describe the setup of the VLA observations, the data reduction procedures and the creation of the final THINGS data products. We present an atlas of the integrated HI maps, the velocity fields, the second moment (velocity dispersion) maps and individual channel maps of each THINGS galaxy. The THINGS data products are made publicly available through a dedicated webpage. Accompanying THINGS papers address issues such as the small-scale structure of the ISM, the (dark) matter distribution in THINGS galaxies, and the processes leading to star formation.

Environmental technologies and competitive advantage
Paul Shrivastava
1995· Strategic Management Journal1.3Kdoi:10.1002/smj.4250160923

In this decade and the coming century, the natural environment will be an important arena for economic, competition. Ecological issues regarding energy, natural resources, pollution, and waste offer both competitive opportunities and constraints, and are changing the competitive landscape in many industries. Corporations can gain competitive advantage by managing ecological variables. This paper explains the concept of ‘environmental technologies’ as a competitive force and a tool for competitive advantage. Environmental technologies offer a new substantive orientation and a management process for minimizing ecological impacts of economic production while enhancing Competitiveness of firms. The practical application of environmental technologies is illustrated using a mini case example of 3M Corporation. Strategic implications of environmental technologies for competitiveness are explored.

SINGS: The<i>SIRTF</i>Nearby Galaxies Survey
Robert C. Kennicutt, L. Armus, G. J. Bendo, Daniela Calzetti +4 more
2003· Publications of the Astronomical Society of the Pacific1.3Kdoi:10.1086/376941

The SIRTF Nearby Galaxy Survey is a comprehensive infrared imaging and spectroscopic survey of 75 nearby galaxies. Its primary goal is to characterize the infrared emission of galaxies and their principal infrared-emitting components, across a broad range of galaxy properties and star formation environments. SINGS will provide new insights into the physical processes connecting star formation to the interstellar medium properties of galaxies, and provide a vital foundation for understanding infrared observations of the distant universe and ultraluminous and active galaxies. The galaxy sample and observing strategy have been designed to maximize the scientific and archival value of the data set for the SIRTF user community at large. The SIRTF images and spectra will be supplemented by a comprehensive multi-wavelength library of ancillary and complementary observations, including radio continuum, HI, CO, submillimeter, BVRIJHK, H-alpha, Paschen-alpha, ultraviolet, and X-ray data. This paper describes the main astrophysical issues to be addressed by SINGS, the galaxy sample and the observing strategy, and the SIRTF and other ancillary data products.

Dynamic Host Configuration Protocol
Ralph Droms
19931.0Kdoi:10.17487/rfc1531

The Dynamic Host Configuration Protocol (DHCP) provides a framework for passing configuration information to hosts on a TCP/IP network. DHCP is based on the Bootstrap Protocol (BOOTP) DHCP captures the behavior of BOOTP relay agents

The Calibration of Mid‐Infrared Star Formation Rate Indicators
Daniela Calzetti, Robert C. Kennicutt, C. W. Engelbracht, Claus Leitherer +4 more
2007· The Astrophysical Journal965doi:10.1086/520082

With the goal of investigating the degree to which the MIR emission traces the SFR, we analyze Spitzer 8 and 24 μm data of star-forming regions in a sample of 33 nearby galaxies with available HST NICMOS images in the Paα (1.8756 μm) emission line. The galaxies are drawn from the SINGS sample and cover a range of morphologies and a factor ~10 in oxygen abundance. Published data on local low-metallicity starburst galaxies and LIRGs are also included in the analysis. Both the stellar continuum-subtracted 8 μm emission and the 24 μm emission correlate with the extinction-corrected Paα line emission, although neither relationship is linear. Simple models of stellar populations and dust extinction and emission are able to reproduce the observed nonlinear trend of the 24 μm emission versus number of ionizing photons, including the modest deficiency of 24 μm emission in the low-metallicity regions, which results from a combination of decreasing dust opacity and dust temperature at low luminosities. Conversely, the trend of the 8 μm emission as a function of the number of ionizing photons is not well reproduced by the same models. The 8 μm emission is contributed, in larger measure than the 24 μm emission, by dust heated by nonionizing stellar populations, in addition to the ionizing ones, in agreement with previous findings. Two SFR calibrations, one using the 24 μm emission and the other using a combination of the 24 μm and Hα luminosities (Kennicutt and coworkers), are presented. No calibration is presented for the 8 μm emission because of its significant dependence on both metallicity and environment. The calibrations presented here should be directly applicable to systems dominated by ongoing star formation.

Motivations for Conserving Urban Biodiversity
DONALD C. DEARBORN, Salit Kark
2009· Conservation Biology715doi:10.1111/j.1523-1739.2009.01328.x

In a time of increasing urbanization, the fundamental value of conserving urban biodiversity remains controversial. How much of a fixed budget should be spent on conservation in urban versus nonurban landscapes? The answer should depend on the goals that drive our conservation actions, yet proponents of urban conservation often fail to specify the motivation for protecting urban biodiversity. This is an important shortcoming on several fronts, including a missed opportunity to make a stronger appeal to those who believe conservation biology should focus exclusively on more natural, wilder landscapes. We argue that urban areas do offer an important venue for conservation biology, but that we must become better at choosing and articulating our goals. We explored seven possible motivations for urban biodiversity conservation: preserving local biodiversity, creating stepping stones to nonurban habitat, understanding and facilitating responses to environmental change, conducting environmental education, providing ecosystem services, fulfilling ethical responsibilities, and improving human well-being. To attain all these goals, challenges must be faced that are common to the urban environment, such as localized pollution, disruption of ecosystem structure, and limited availability of land. There are, however, also challenges specific only to particular goals, meaning that different goals will require different approaches and actions. This highlights the importance of specifying the motivations behind urban biodiversity conservation. If the goals are unknown, progress cannot be assessed.

Supporting Autonomy in the Classroom: Ways Teachers Encourage Student Decision Making and Ownership
Candice Stefanou, Kathleen C. Perencevich, Matthew J. Dicintio, Julianne C. Turner
2004· Educational Psychologist700doi:10.1207/s15326985ep3902_2

Abstract In addition to classroom activities, teachers provide personal and instructional supports meant to facilitate the developing sense of student autonomy. In this article, we offer a way of thinking about autonomy-supportive practices that suggests that such practices can be distinguished at a featural level and that different practices may in fact have different outcomes in terms of student classroom behavior. Specifically, we propose that autonomy support can be manifested in the classroom in at least 3 distinct ways: organizational autonomy support (e.g., allowing students some decision-making role in terms of classroom management issues), procedural autonomy support (e.g., offering students choices about the use of different media to present ideas), and cognitive autonomy support (e.g., affording opportunities for students to evaluate work from a self-referent standard). We offer vignettes of teachers in their classes to illustrate our proposition that autonomy support may be carried out on several planes and may produce different outcomes. Whereas organizational autonomy support may encourage a sense of well-being and comfort with the way a classroom functions and procedural autonomy support may encourage initial engagement with learning activities, cognitive autonomy support may foster a more enduring psychological investment in deep-level thinking.

Shackled to the Status Quo: The Inhibiting Effects of Incumbent System Habit, Switching Costs, and Inertia on New System Acceptance1
Greta L. Polites, Elena Karahanna
2012· MIS Quarterly670doi:10.2307/41410404

Given that adoption of a new system often implies fully or partly replacing an incumbent system, resistance is often manifested as failure of a user to switch from an incumbent technology to a newly introduced one. Thus, a potential source of resistance to adopting a new system lies in the use of an incumbent system. Using the status quo bias and habit literatures as theoretical lenses, the study explains how use of an incumbent system negatively impacts new system perceptions and usage intentions. We argue that habitual use of an incumbent system, rationalization due to perceived transition costs, and psychological commitment due to perceived sunk costs all encourage development of inertia. Inertia in turn fully mediates the impact of these incumbent system constructs on constructs related to acceptance of the new system via psychological commitment based on cognitive consistency and by increasing the importance of normative pressures. Specifically, we hypothesize that inertia leads to decreased perceptions of the ease of use and relative advantage of a newly introduced system and has a negative impact on intentions to use the new system, above and beyond its impact through perceptions. Finally, we hypothesize that inertia moderates the relationship between subjective norm and intention, such that normative pressures to use a new system become more important in the presence of inertia. Empirical results largely support the hypothesized relationships showing the inhibiting effect of incumbent-system habit, transition and sunk costs, and inertia on acceptance of a new system. Our study thus extends theoretical understanding of the role of incumbent system constructs such as habit and inertia in technology acceptance, and lays the foundations for further study of the interplay between perceptions and cognition with respect to the incumbent system and those with respect to a new system.

Star Formation in NGC 5194 (M51a). II. The Spatially Resolved Star Formation Law
Robert C. Kennicutt, Daniela Calzetti, Fabian Walter, G. Hélou +4 more
2007· The Astrophysical Journal574doi:10.1086/522300

We have studied the relationship between the star formation rate (SFR), surface density, and gas surface density in the spiral galaxy M51a (NGC 5194), using multiwavelength data obtained as part of the Spitzer Infrared Nearby Galaxies Survey (SINGS). We introduce a new SFR index based on a linear combination of Halpha emission-line and 24 mum continuum luminosities, which provides reliable extinction-corrected ionizing fluxes and SFR densities over a wide range of dust attenuations. The combination of these extinction-corrected SFR densities with aperture synthesis H I and CO maps has allowed us to probe the form of the spatially resolved star formation law on scales of 0.5-2 kpc. We find that the resolved SFR versus gas surface density relation is well represented by a Schmidt power law, which is similar in form and dispersion to the disk-averaged Schmidt law. We observe a comparably strong correlation of the SFR surface density with the molecular gas surface density, but no significant correlation with the surface density of atomic gas. The best-fitting slope of the Schmidt law varies from N=1.37 to 1.56, with zero point and slope that change systematically with the spatial sampling scale. We tentatively attribute these variations to the effects of areal sampling and averaging of a nonlinear intrinsic star formation law. Our data can also be fitted by an alternative parameterization of the SFR surface density in terms of the ratio of gas surface density to local dynamical time, but with a considerable dispersion.

When That Tune Runs Through Your Head: A PET Investigation of Auditory Imagery for Familiar Melodies
Andrea R. Halpern
1999· Cerebral Cortex548doi:10.1093/cercor/9.7.697

The present study used positron emission tomography (PET) to examine the cerebral activity pattern associated with auditory imagery for familiar tunes. Subjects either imagined the continuation of nonverbal tunes cued by their first few notes, listened to a short sequence of notes as a control task, or listened and then reimagined that short sequence. Subtraction of the activation in the control task from that in the real-tune imagery task revealed primarily right-sided activation in frontal and superior temporal regions, plus supplementary motor area (SMA). Isolating retrieval of the real tunes by subtracting activation in the reimagine task from that in the real-tune imagery task revealed activation primarily in right frontal areas and right superior temporal gyrus. Subtraction of activation in the control condition from that in the reimagine condition, intended to capture imagery of unfamiliar sequences, revealed activation in SMA, plus some left frontal regions. We conclude that areas of right auditory association cortex, together with right and left frontal cortices, are implicated in imagery for familiar tunes, in accord with previous behavioral, lesion and PET data. Retrieval from musical semantic memory is mediated by structures in the right frontal lobe, in contrast to results from previous studies implicating left frontal areas for all semantic retrieval. The SMA seems to be involved specifically in image generation, implicating a motor code in this process.

Ecocentric Management for a Risk Society
Paul Shrivastava
1995· Academy of Management Review539doi:10.5465/amr.1995.9503271996

A central feature of postindustrial modernization is the proliferation of technological and environmental risks and crises. These risks and crises emanate from corporate industrial activities. The traditional management paradigm is limited in several ways for responding to demands of the risk society and should be abandoned. I propose an alternative “ecocentric” paradigm for management in the risk society context, which advocates an ecologically centered conception of interorganizational relations and internal management activities. Thus, organizations are viewed as situated within bioregionally sustainable industrial ecosystems, relating to each other through a logic of ecological interdependence. Within this context, ecocentric management seeks to minimize the environmental impact of organizational vision, inputs, throughputs, and outputs. Implications of this paradigm for management practice and research are examined.

Fractals and cancer.
James W. Baish, R K Jain
2000· PubMed537

Recent studies have shown that fractal geometry, a vocabulary of irregular shapes, can be useful for describing the pathological architecture of tumors and, perhaps more surprisingly, for yielding insights into the mechanisms of tumor growth and angiogenesis that complement those obtained by modern molecular methods. This article outlines the basic methods of fractal geometry and discusses the value and limitations of applying this new tool to cancer research.

Gender Differences in Coping with Stress: When Stressor and Appraisals Do Not Differ
J. T. Ptacek, Ronald E. Smith, Kenneth L. Dodge
1994· Personality and Social Psychology Bulletin503doi:10.1177/0146167294204009

In an attempt to control for the effects of event type on sex differences in coping, men and women responded to an identical achievement-related stressor under controlled laboratory conditions. Although men and women were similar in their cognitive appraisal of the situation, they nonetheless reported differences in preparatory coping. Women reported seeking social support and using emotion-focused coping to a greater extent than men, whereas men reported using relatively more problem-focused coping than women. The masculinity and femininity of respondents failed to moderate the relation between sex and coping. These results are inconsistent with a purely situational explanation of sex differences in coping but are consistent with the notion that men and women are socialized to cope with stress in different ways.

Search for Electron Neutrino Appearance at the<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mi>Δ</mml:mi><mml:msup><mml:mi>m</mml:mi><mml:mn>2</mml:mn></mml:msup><mml:mo>∼</mml:mo><mml:mn>1</mml:mn><mml:mtext> </mml:mtext><mml:mtext> </mml:mtext><mml:msup><mml:mi>eV</mml:mi><mml:mn>2</mml:mn></mml:msup></mml:math>Scale
A. A. Aguilar-Arevalo, A. O. Bazarko, S. J. Brice, Bruce Brown +4 more
2007· Physical Review Letters499doi:10.1103/physrevlett.98.231801

The MiniBooNE Collaboration reports first results of a search for nu e appearance in a nu mu beam. With two largely independent analyses, we observe no significant excess of events above the background for reconstructed neutrino energies above 475 MeV. The data are consistent with no oscillations within a two-neutrino appearance-only oscillation model.

Development and Validation of a Multidimensional Measure of Sport-Specific Psychological Skills: The Athletic Coping Skills Inventory-28
Ronald E. Smith, Robert W. Schutz, Frank L. Smoll, J. T. Ptacek
1995· Journal of Sport and Exercise Psychology484doi:10.1123/jsep.17.4.379

Confirmatory factor analysis was used as the basis for a new form of the Athletic Coping Skills Inventory (ACSI). The ACSI-28 contains seven sport-specific subscales: Coping With Adversity, Peaking Under Pressure, Goal Setting/Mental Preparation, Concentration, Freedom From Worry, Confidence and Achievement Motivation, and Coachability. The scales can be summed to yield a Personal Coping Resources score, which is assumed to reflect a multifaceted psychological skills construct. Confirmatory factor analyses demonstrated the factorial validity of the ACSI-28, as the seven subscales conform well to the underlying factor structure for both male and female athletes. Psychometric characteristics are described, and preliminary evidence for construct and predictive validity is presented.

The Overspent American: Upscaling, Downshifting, and the New Consumer
Janet T. Knoedler
1999· Journal of Economic Issues483doi:10.1080/00213624.1999.11506198

(1999). The Overspent American: Upscaling, Downshifting, and the New Consumer. Journal of Economic Issues: Vol. 33, No. 3, pp. 747-750.

The BIMA Survey of Nearby Galaxies (BIMA SONG). II. The CO Data
Tamara T. Helfer, Michele D. Thornley, Michael W. Regan, Tony Wong +4 more
2003· The Astrophysical Journal Supplement Series474doi:10.1086/346076

The BIMA Survey of Nearby Galaxies is a systematic imaging study of the 3 mm CO J = 1--0 molecular emission within the centers and disks of 44 nearby spiral galaxies. The typical spatial resolution of the survey is 6", or 360 pc at the average distance (12 Mpc) of the sample, over a field of view of 10kpc. The velocity resolution of the CO observations is 4 km/s. The sample was not chosen based on CO or infrared brightness; instead, all spirals were included that met the selection criteria of vsun <= 2000 km/s, dec >= -20deg, inc <= 70deg, D25 < 70', and BT < 11.0. The detection rate was 41/44 sources or 93%. Fully-sampled single-dish CO data were incorporated into the maps for 24 galaxies; these single-dish data comprise the most extensive collection of fully-sampled, two-dimensional single-dish CO maps of external galaxies to date. We also tabulate direct measurements of the global CO flux densities for these 24 sources. We demonstrate that the measured ratios of flux density recovered are a function of the signal-to-noise of the interferometric data. We examine the degree of central peakedness of the molecular surface density distributions and show that the distributions exhibit their brightest CO emission within the central 6" in only 20/44 or 45% of the sample. We show that all three Local Group spiral galaxies have CO morphologies that are represented in SONG, though the Milky Way CO luminosity is somewhat below the SONG average, and M31 and M33 are well below average. This survey provides a unique public database of integrated intensity maps, channel maps, spectra, and velocity fields of molecular emission in nearby galaxies.

Structures of Cage, Prism, and Book Isomers of Water Hexamer from Broadband Rotational Spectroscopy
Cristóbal Pérez, Matt T. Muckle, Daniel P. Zaleski, Nathan A. Seifert +4 more
2012· Science474doi:10.1126/science.1220574

Theory predicts the water hexamer to be the smallest water cluster with a three-dimensional hydrogen-bonding network as its minimum energy structure. There are several possible low-energy isomers, and calculations with different methods and basis sets assign them different relative stabilities. Previous experimental work has provided evidence for the cage, book, and cyclic isomers, but no experiment has identified multiple coexisting structures. Here, we report that broadband rotational spectroscopy in a pulsed supersonic expansion unambiguously identifies all three isomers; we determined their oxygen framework structures by means of oxygen-18-substituted water (H(2)(18)O). Relative isomer populations at different expansion conditions establish that the cage isomer is the minimum energy structure. Rotational spectra consistent with predicted heptamer and nonamer structures have also been identified.