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Google Scholar (GS) is an important tool that faculty, administrators, and external reviewers use to evaluate the scholarly impact of candidates for jobs, tenure, and promotion. This article highlights both the benefits of GS—including the reliability and consistency of its citation counts and its platform for disseminating scholarship and facilitating networking—and its pitfalls. GS has biases because citation is a social and political process that disadvantages certain groups, including women, younger scholars, scholars in smaller research communities, and scholars opting for risky and innovative work. GS counts also reflect practices of strategic citation that exacerbate existing hierarchies and inequalities. As a result, it is imperative that political scientists incorporate other data sources, especially independent scholarly judgment, when making decisions that are crucial for careers. External reviewers have a unique obligation to offer a reasoned, rigorous, and qualitative assessment of a scholar’s contributions and therefore should not use GS.
Good education requires student experiences that deliver lessons about practice as well as theory and that encourage students to work for the public good—especially in the operation of democratic institutions (Dewey 1923; Dewy 1938). We report on an evaluation of the pedagogical value of a research project involving 23 colleges and universities across the country. Faculty trained and supervised students who observed polling places in the 2016 General Election. Our findings indicate that this was a valuable learning experience in both the short and long terms. Students found their experiences to be valuable and reported learning generally and specifically related to course material. Postelection, they also felt more knowledgeable about election science topics, voting behavior, and research methods. Students reported interest in participating in similar research in the future, would recommend other students to do so, and expressed interest in more learning and research about the topics central to their experience. Our results suggest that participants appreciated the importance of elections and their study. Collectively, the participating students are engaged and efficacious—essential qualities of citizens in a democracy.
Thermocapillary dewetting of liquids and molten films has recently emerged as a viable alternative to conventional microprocessing methods. As this thermal gradient-induced mechanism is universal, it can be applied to any material. This work explores the sequential dewetting of materials with varying melting points, including polymers and metals, to create aligned morphologies. The variation in melting point allows for the dewetting of single layers at a time or mobility-limited simultaneous dewetting. As a result, a variety of multimaterial structures can be produced with built-in alignment, such as arrays of concentric circles, lines with periodic segmentation, or islands on holes. This approach employs photothermal methods to induce the necessary thermal gradient, manipulating several variables in order to influence the consequent structures. Adjusting laser power and light intensity allows for the control of temperature for selective dewetting of films; altering beam size and exposure time affects the extent of dewetting in terms of diameter size; overlap effects and simultaneous dewetting can result in complex architectures. This controlled writing of patterns also presents a technique to create both masks at low temperatures for conductive multilayers as well as templates for electrospray deposition.
be a compact 4-manifold with boundary. We study the space of hyperkähler triples
, modulo diffeomorphisms which are the identity on the boundary. We prove that this moduli space is a smooth infinite-dimensional manifold and describe the tangent space in terms of triples of closed anti-self-dual 2-forms. We also explore the corresponding boundary value problem: a hyperkähler triple restricts to a closed framing of the bundle of 2-forms on the boundary; we identify the infinitesimal deformations of this closed framing that can be filled in to hyperkähler deformations of the original triple. Finally we study explicit examples coming from gravitational instantons with isometric actions of
We deal with aspects of direct and inverse problems in parameterized Picard–Vessiot (PPV) theory. It is known that, for certain fields, a linear differential algebraic group (LDAG)
is a PPV Galois group over these fields if and only if
contains a Kolchin-dense finitely generated group. We show that, for a class of LDAGs
, including unipotent groups,
is such a group if and only if it has differential type
. We give a procedure to determine if a parameterized linear differential equation has a PPV Galois group in this class and show how one can calculate the PPV Galois group of a parameterized linear differential equation if its Galois group has differential type
While it had long been recognized that herbivores are simultaneously influenced by natural enemies (Hairston et al. 1960) and plant defences (Fraenkel 1959), Price et al. (1980) were among the first to argue forcefully that these dual factors must be considered together. They argued that ‘[w]e cannot understand the plant–herbivore interaction without understanding the role of enemies. We cannot understand predator–prey interactions without understanding the role of plants’ (Price et al. 1980, p. 59). This holistic, tritrophic perspective conceptually unites theory from at least three areas of ecological and evolutionary research. First, this tritrophic perspective expands our view on plant defence from one based strictly on the direct defence, to one that also considers the indirect defence of plants by natural enemies (Janzen 1966; Turlings et al. 1990), as well as how natural enemies mediate the efficacy of direct defences (Moran and Hamilton 1980; Clancy and Price 1987; Williams 1999; Gassmann and Hare 2005). Second, this tritrophic perspective advances our understanding of the forces shaping the evolution of herbivore host plant choice and diet breadth by incorporating the interactive effects of host plant quality and risk of attack by natural enemies (Bernays 1998; Singer et al. 2004a, b). And third, this tritrophic perspective provides a mechanistic framework for understanding the ecological and evolutionary factors that determine the strength of the indirect effects natural enemies have on plant growth, i.e., trophic cascades (Mooney et al. 2010).
Tritrophic interactions have received considerable attention in agricultural systems, with numerous studies documenting the effects of crop traits on herbivores and their natural enemies (Hare 1992; Tumlinson et al. 1992; Vet and Dicke 1992; Bottrell et al. 1998; Turlings and Benrey 1998; Cortesaro et al. 2000; Hare 2002; Ode 2006). In contrast, comparatively little is known of the influences of plant traits on herbivore–enemy interactions from natural systems (e.g., Hare 1992, 2002). Our goals in this review are three-fold. First, where past reviews on this topic have focused on agricultural systems (e.g., Hare 1992, 2002), we give special attention to the evidence for plant variation in herbivore–enemy interactions from natural communities. Second, we position this topic within the framework of trait- and density-mediated indirect interactions. Finally, we consider the evolutionary and ecological implications of plant variation in herbivore–enemy interactions, and we do so with specific reference to the different mechanistic pathways by which such plant effects can occur.
Creative writing, whether in literature or science, may well seem like an enjoyable pastime to its readers, but it most certainly involves hard work, intense concentration, and periods of uncertainty and blockage for even the most productive of its practitioners. No wonder the ancient Greeks and Romans called on specific deities or immortals like the Muses to guide them past inevitable hesitancies into more freely flowing streams of thought. Even the Christian poet Dante sought the aid of the pagan epic poet Virgil as his leader through his literary traversal of the realms of the afterlife. Such breakthroughs into creative production often come about through vivid daytime fantasies or suggestive night dreams that we now can recognize are natural human occurrences and not necessarily visitations from Olympian deities.
Many anecdotal reports by creative scientists, artists, and writers suggest that periods of creative impasse can be terminated by the occurrence of vivid day or night dreams (Garfield, 1974; Shepard, 1978; Singer, 1975, 2004). Albert Einstein described how his waking fantasies of himself or some alter ego traveling through space at the speed of light and then picturing the consequences of such actions opened the way for his development of his theory of relativity. Niels Bohr described how learning of his son's involvement in an act of petty thievery led to his trying to reconcile his nearly simultaneous feelings of anger and disappointment about the boy with his fatherly feelings of love and protectiveness.
In the three centuries or so since the modern international system began flo take on its present shape, its component members have come together in a wide variety of organizations, for a wide variety of purposes. Those who act on behalf of the nations have turned to international organizations to oversee peace settlements, to strengthen their collective defense capacity, to mediate conflicts between themselves, to discourage interference from the outside, to harmonize their trade relations, to supervise international waterways, to accelerate the production of food, to codify diplomatic practice, and to formalize legal proceedings. Some organizations are established primarily for the neutral purpose of making coexistence possible, others for the more affirmative purposes of positive cooperation. Some have been directed toward the modification of the system, others toward the preservation of its status quo.
It has often been observed that recent converts to any belief system tend to be among its most zealous adherents, and science (despite its emphasis on objectivity and detachment) has proved no exception. As the canons of scientific inquiry begin to take hold in each field of human knowledge, there have appeared those who seem, as it were, more royalist than the king. For these scholars the rules of scientific inference are not guidelines to be used with care but dogmas to be pursued unswervingly; to them science is not, as someone once expressed it, “attenuated common sense” but a totally different and rather severe regimen of thought.
In any field of scholarly inquiry it is recognized that we must describe before we can hope toexplain. That is, we cannot account for the incidence of a certain class of events or conditions until we have identified and described those particular phenomena. If we agree that the current state of theory in the field of international organization leaves much to be desired, this fact may be partly due to our violation of this principle. Whether we deal with all international organizations over a lengthy period of time or a smaller subset based on such inclusion criteria as function or time period and whether we treat such organizations as the dependent, intervening, or independent variable, it is essential that we first acquire the data by which such organizations can be described. The major purpose of this article is to report the results of a first systematic effort to generate this data, so that we may move on in a cumulative fashion toward the empirical testing of propositions, models, or theories in which international organization is a major variable.
This paper is an expanded version of the 10 lectures I gave as the 2006 London Mathematical Society Invited Lecture Series at the Heriot-Watt University, 31 July - 4 August 2006. My goal was to give the audience an introduction to the algebraic, analytic and algorithmic aspects of the Galois theory of linear differential equations by focusing on some of the main ideas and philosophies and on examples. There are several texts ([1, 2, 3, 4, 5] to name a few) that give detailed expositions and I hope that the taste offered here will encourage the reader to dine more fully with one of these.
The rest of the paper is organized as follows. In Section 1.2, What is a Linear Differential Equation?, I discuss three ways to think about linear differential equations: scalar equations, linear systems and differential modules. Just as it is useful to think of linear maps in terms of linear equations, matrices and associated modules, it will be helpful in future sections to go back and forth between the different ways of presenting linear differential equations.
In Section 1.3, Basic Galois Theory and Applications, I will give the basic definitions and describe the Galois correspondence. In addition I will describe the notion of monodromy and its relation to the Galois theory. I will end by giving several applications and ramifications, one of which will be to answer the question Although y = cos x satisfies y″ + y = 0, why doesn't sec x satisfy a linear differential equation?