281 research outputs found
The elliptic sieve and Brauer groups
No full textA theorem of Serre states that almost all plane conics over Q have no rational point. We prove an analogue of this for families of conics parametrised by elliptic curves using elliptic divisibility sequences and a version of the Selberg sieve for elliptic curves. We also give more general results for specialisations of Brauer groups, which yields applications to norm form equations
Fibrations with few rational points
No full textWe study the problem of counting the number of varieties in families which have a rational point. We give conditions on the singular fibres that force very few of the varieties in the family to contain a rational point, in a precise quantitative sense. This generalises and unifies existing results in the literature by Serre, Browning–Dietmann, Bright–Browning–Loughran, Graber–Harris–Mazur–Starr, et al.</p
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Individual Difference and Deterrence
No full textThis chapter builds on the concept on individual differences in deterrence theory in several important ways. First, we review recent studies expressly designed to test for heterogeneous deterrent effects based on individual differences, mainly focusing on the role of criminal propensity as a moderating factor in the deterrence process. Second, we argue for a focus on individual differences in the sensitivity to rewards from crime as a new and theoretically rich dimension around which to study this concept. Finally, we outline future directions for the study of individual differences in the deterrence process, specifically by considering the limitations of most current data sets used for exploring offender decision-making, and ways in which future studies on the topic can be planned out.
This chapter builds on the concept on individual differences in deterrence theory in several important ways. It reviews some recent advancements on this topic in the key areas identified by the Piquero et al. review, which represent studies expressly designed to test for heterogeneous deterrent effects based on individual differences. These recent studies tend to focus on the role of criminal propensity as a moderating factor in the deterrence process. The chapter focuses on a new dimension for consideration largely overlooked by many scholars—individual differences in the sensitivity to rewards from crime. It explores future directions for the study of individual differences in the deterrence process. Thomas A. Loughran, Greg Pogarsky, Alex R. Piquero, and Raymond Paternoster lay out a rationale to advance the notion of differential deterrence by arguing that "evidence of heterogeneity can show that some offenders may be more deterrable than others; that is, they may react and adjust their sanction threat perceptions in heterogeneous ways"
Manin’s conjecture for a singular sextic del Pezzo surface
No full textWe prove Manin’s conjecture for a del Pezzo surface of degree six which has one singularity of type A2. Moreover, we achieve a meromorphic continuation and explicit expression of the associated height zeta function.</p
Manin's conjecture for a singular quartic del Pezzo surface
No full textWe prove Manin's conjecture for a split singular quartic del Pezzo surface with singularity type 2A1 and eight lines. This is achieved by equipping the surface with a conic bundle structure. To handle the sum over the family of conics, we prove a result of independent interest on a certain restricted divisor problem for four binary linear forms. 2012 London Mathematical Society2012</p
Jersey City - Statue of St. Peter The Apostle on Campus of St. Peter University
No full textThis sculpture of Saint Peter, the Apostle, at St. Peter's College was executed by Brian Hanlon at the commission of the late Fr Loughran SJ in 2004.Original file name Statue of St. Peter.jp
Chapter 9: Shock and Offence Online: The Role of Emotion in Participant Absent Research
No full textPurpose - This chapter considers the implications of online participant absent research, that is where the researcher has no interaction with the author, on researcher emotion. Drawing on a study of data extracts ‘mined’ from the Internet without interaction with the author, lessons for practice are identified. It is argued that researchers should reflexively consider the ways in which passive data collection techniques may impact the researcher prior to undertaking research, in order to ensure that researchers are adequately supported.
Methodology/approach –The data described in this example were constructed around a single case study where a woman had been asked to leave a sports shop in the UK because she was breastfeeding. Not allowing breastfeeding within a business is illegal in the UK, and resulted in a protest. The study involved analysis of user-generated data from an online news site and Twitter in relation to this case.
Findings - Drawing on field notes and conversations with colleagues, I argue that in order to successfully manage my emotional response to the data, it was necessary to distance myself during analysis.
Originality/value – Whilst the role of emotion is often considered as part of ethnographic practice in studies utilising face-to-face data collection, it is underexplored in the online domain. This chapter presents, through a detailed example, a reflective account of the emotion work required in one such study. Strategies to reflexively manage emotion for those undertaking participant absent research, which are applicable to both online and off-line situations, are highlighted
The Aftermarket Performance of Initial Public Offerings in Canada
No full textIn this paper, we empirically investigate Canadian initial public offerings (IPOs) to provide one case on the international evidence on the long-run performance of IPOs. Specifically, we examine whether the choice of a performance measurement methodology directly determines both the size and power of statistical test, as documented in previous studies (Mitchell and Stafford, 2000; Loughran and Ritter, 2000; and Brav, Geczy and Gompers, 2000). Our sample consists of 445 IPOs between January 1991 and December 1998. Using cumulative abnormal returns as an abnormal performance measure, we find that the Canadian IPOs underperform significantly the sample of seasoned firms with the same market capitalization. More specifically, the 3 year and the 5 year underperformances estimated on value weighted (VW) basis are statistically significant. Moreover, using the buy-and hold returns as an alternative measurement for long-run performance, we find that investors who buy immediately after listing and hold shares for five years will make a loss of 24,66%, on equally weighted (EW) basis (15,16% on VW basis) relative to an investment in the control firms. Using the calendar-time returns method, we find that the 5 years underperformance is 25,6% on EW basis (19,22% on VW basis). We have entertained a number of possible explanations for the poor subsequent performance of issuing firms. While, the fads or investor's overreactions and divergence of opinions hypotheses do not apply in explaining the aftermarket performance of Canadian IPOs, our evidence is consistent with the hot issue market story. La présente étude contribue à l'analyse internationale de la performance à long terme des émissions initiales, menée dans différents pays, en analysant les émissions canadiennes de la période 1992-1998. Nous examinons en particulier dans quelle mesure le choix des mesures de performance influence à la fois l'amplitude des résultats et la puissance des tests statistiques, comme l'affirment plusieurs auteurs tels Mitchell and Stafford (2000), Loughran and Ritter (2000) ainsi que Brav, Geczy et Gompers (2000). L'échantillon inclut 445 émissions initiales réalisées entre0101 1991 et1101 1991. Lorsque la méthode des résidus cumulés est utilisée pour mesurer la performance anormale, nous observons que les émissions initiales canadiennes ont une performance significativement inférieure à celle d'entreprises pairées, de taille semblable qui n'ont pas procédé à des émissions. Les résidus moyens pondérés calculés après 3 ou 5 ans sont négatifs lorsque ces rendements sont pondérés par les valeurs des produits bruts. L'effet n'est donc pas imputable uniquement aux petites émissions. Lorsque la méthode de la détention passive est utilisée, nous estimons la perte de richesses des acquéreur des émissions qui les détiennent pendant 5 ans à 24,66% de leur richesse initiale. L'examen des facteurs explicatifs de la performance à moyen et long terme semble confirmer l'hypothèse des fenêtres d'opportunité, alors que les hypothèses basées sur l'irrationalité ou la sur réaction ne semblent pas confirmées.Initial public offerings; long term performance; Canada, Émissions initiales, sous performance à long terme, Canada
The number of varieties in a family which contain a rational point
No full textWe consider the problem of counting the number of varieties in a family over a number field which contain a rational point. In particular, for products of Brauer-Severi varieties and closely related counting functions associated to Brauer group elements. Using harmonic analysis on toric varieties, we provide a positive answer to a question of Serre on such counting functions in some cases. We also formulate some conjectures on generalisations of Serre's problem
Hasse principle for a family of K3 surfaces
No full textIn this talk we study the Hasse principle for the family of "diagonal K3 surfaces of degree 2", given by the explicit equations:
I will explain how many such surfaces, when ordered by their coefficients, have a Brauer-Manin obstruction to the Hasse principle. This is joint work with Damián Gvirtz and Masahiro Nakahara.Non UBCUnreviewedAuthor affiliation: University of BathResearche
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