Monotonicity of Degrees of Generalized Alexander Polynomials of Groups and 3-Manifolds

We investigate the behavior of the higher-order degrees, db_n, of a finitely presented group G. These db_n are functions from H^1(G;Z) to Z whose values are the degrees certain higher-order Alexander polynomials. We show that if def(G) is at least 1 or G is the fundamental group of a compact, orientable 3-manifold then db_n is a monotonically increasing function of n for n at least 1. This is false for general groups. As a consequence, we show that if a 4 manifold of the form X times S^1 admits a symplectic structure then X ``looks algebraically like'' a 3-manifold that fibers over S^1, supporting a positive answer to a question of Taubes. This generalizes a theorem of S. Vidussi and is an improvement on the previous results of the author. We also find new conditions on a 3-manifold X which will guarantee that the Thurston norm of f*(psi), for psi in H^1(X;\Z) and f:Y -> X a surjective map on pi_1, will be at least as large the Thurston norm of psi. When X and Y are knot complements, this gives a partial answer to a question of J. Simon. More generally, we define Gamma-degrees, db_Gamma, corresponding to a surjective map G -> Gamma for which Gamma is poly-torsion-free-abelian. Under certain conditions, we show they satisfy a monotonicity condition if one varies the group. As a result, we show that these generalized degrees give obstructions to the deficiency of a group being positive and obstructions to a finitely presented group being the fundamental group of a compact, orientable 3-manifold.Comment: 19 page

Grading Grain Under the U.S. Grain Standards

Crop Production/Industries,

The Korteweg-de Vries equation and water waves. Part 2. Comparison with experiments

The Korteweg-de Vries (KdV) equation is tested experimentally as a model for moderate amplitude waves propagating in one direction in relatively shallow water of uniform depth. For a wide range of initial data, comparisons are made between the asymptotic wave forms observed and those predicted by the theory in terms of the number of solitons that evolve, the amplitude of the leading soliton, the asymptotic shape of the wave and other qualitative features. The KdV equation is found to predict accurately the number of evolving solitons and their shapes for initial data whose asymptotic characteristics develop in the test section of the wave tank. The accuracy of the leading-soliton amplitudes computed by the KdV equation could not be conclusively tested owing to the viscous decay of the measured wave amplitudes; however, a procedure is presented for estimating the decay in amplitude of the leading wave. Computations suggest that the KdV equation predicts the amplitude of the leading soliton to within the expected error due to viscosity (12%) when the non-decayed amplitudes are less than about a quarter of the water depth. Indeed, agreement to within about 20% is observed over the entire range of experiments examined, including those with initial data for which the non-decayed amplitudes of the leading soliton exceed half the fluid depth

The narrative coherence of witness transcripts in children on the autism spectrum

Background and Aims. Autistic children often recall fewer details about witnessed events than typically developing children (of comparable age and ability), although the information they recall is generally no less accurate. Previous research has not examined the narrative coherence of such accounts, despite higher quality narratives potentially being perceived more favourably by criminal justice professionals and juries. This study compared the narrative coherence of witness transcripts produced by autistic and typically developing (TD) children (ages 6-11 years, IQs 70+). Methods and Procedures. Secondary analysis was carried out on interview transcripts from a subset of 104 participants (autism=52, TD=52) who had taken part in a larger study of eyewitness skills in autistic and TD children. Groups were matched on chronological age, IQ and receptive language ability. Coding frameworks were adopted from existing narrative research, featuring elements of ‘story grammar’. Outcomes and Results. Whilst fewer event details were reported by autistic children, there were no group differences in narrative coherence (number and diversity of ‘story grammar’ elements used), narrative length or semantic diversity. Conclusions and Implications. These findings suggest that the narrative coherence of autistic children’s witness accounts is equivalent to TD peers of comparable age and ability

Relative Abundance, Seasonal Distribution and Taxonomy of Sphingidae of Northeast Arkansas

A total of 38 species of sphingids, with keys and descriptions, are reported from Northeast Arkansas. Graphs and tables are presented to show relative abundance and seasonal distribution. Drawings of genitalia, fore tibiae, and forewings, as well as photographs of species in the key are included

Performing for Hollywood: Coloniality and the Tourist Image in Esteban Ramírez’s Caribe (2004)

This article problematizes US-Costa Rican cultural and ideological relations through an analysis of the film Caribe / Caribbean (2004) by Esteban Ramírez, positing that the film unconsciously invites an international audience to colonize it via the tourist gaze. Beginning by considering Ramírez’s anti-imperialist stance within the film’s plot which underscores the sovereignty of the Central American nation, I argue that these aims are undone through the exoticization of space and place. This article therefore goes on to analyse the ways in which the tropical image of the nation is seen to be internalized by the film, as well as considering the hegemonic Hollywood tropes of ethnicity and gender which are mimicked and performed

Collective Culpability in Costa Rica: The Case of Quince Duncan’s Kimbo

Despite Costa Rica’s peaceful rhetoric, Quince Duncan’s 1989 novel, Kimbo, portrays civil society as so corrupt it would rather condemn and kill an innocent man than admit to individual faults. This article therefore considers the nation as a crime scene in Kimbo, whereby the State and its deputies are the perpetrators of several crimes. Using Antonio Gramsci’s and Louis Althusser’s concepts of the State, civil society and subaltern to discuss the idea of a nationwide, collective culpability, it analyses the roles played by the ‘voices’ versus the ‘voiceless’ in the novel. It argues that the former group incorporates Repressive State Apparatus and Ideological State Apparatus, such as the police, judiciary and the Catholic Church, while the latter comprises marginalized groups such as Afro–Costa Ricans, women and the poor

Living Behind Bars: Representations of the Costa Rican Home in Cinematic Works by Hernán Jiménez

‘¿Por qué hay tantas rejas? Todas esas casas parecen jaulas.’ [Why are there so many bars? All these houses look like cages]. Hernán Jiménez’s central character, Antonio, poses this question in the national box-office hit, El regreso [The Return] (2011), upon returning to his hometown of San José, Costa Rica, after a decade living in New York. The home as an imprisoning space which mirrors what Jiménez sees as the oppressive atmosphere of the nation’s capital is a recurring theme in his work and this article therefore considers the domestic space as a place of fear and unease rather than comfort and rest, analysing the role of security, family, and home in Costa Rica. These reflections are explored with reference to three of Jiménez’s cinematic works: the documentary Doble llave y cadena [Double Lock and Chain] (2005), and the two feature-length fiction films A ojos cerrados [Closed Eyes] (2009) and El regreso (2011), which are analysed according to Homi K. Bhabha and Dwayne Avery’s conceptions of the unhomely home

Developing best practice for infilling daily river flow data

Complete river flow time series are indispensable to the sustainable management of water resources and even very short gaps can severely compromise data utility. Suitably-flagged flow estimates, derived via judicious infilling, are thus highly beneficial. The UK National River Flow Archive provides stewardship of and access to daily river flow records from over 1500 gauging stations and, whilst the majority are sensibly complete, historical validation reveals a significant quantity of gaps. A full assessment of the suitability of existing techniques for infilling such gaps is lacking. This paper therefore presents an appraisal of various simple infilling techniques, including regression, scaling and equipercentile analysis, according to their ability to generate daily flow estimates for 25 representative UK gauging stations. All of the techniques rely upon data transfer from donor stations and results reveal that the equipercentile and multiple regression approaches perform best. Case studies offer further insight and an example of infilling is presented, along with areas of future study. The results demonstrate the potential for developing generic infilling methodologies to ensure a consistent and auditable approach towards infilling, which could find wider application both within the UK and internationally

Mediated intimacy: Sex advice in media culture

The bold argument of Mediated Intimacy (Barker et al., 2018)1 is that media of various kinds play an increasingly important role in shaping people’s knowledge, desires, practices and expectations about intimate relationships. While arguments rage about the nature and content of sex and relationship education in schools, it is becoming clear that more and more of us – young and old – look not to formal education, or even to our friends, for information about sex, but to the media (Albury, 2016; Attwood et al., 2015). This is not simply a matter of media ‘advice’ in the form of self-help books, magazine problem pages, or online ‘agony’ columns – though these are all proliferating and are discussed at length in the book. It is also about the wider cultural habitat of images, ideas and discourses about intimacy that circulate through and across media: the ‘happy endings’ of romantic comedies; the ‘money shots’ of pornography; the celebrity gossip about who is seeing whom, who is ‘cheating’, and who is looking ‘hot’; the lifestyle TV about ‘embarrassing bodies’ or being ‘undateable’; the newspaper features on how to have a ‘good’ divorce or ‘ten things never to say on a first date’; the new apps that incite us to quantify and rate our sex lives, and so forth. These constitute the ‘taken for granted’ of everyday understandings of intimacy, and they are at the heart of Mediated Intimacy