2,144 research outputs found
Grid Graphs, Gorenstein Polytopes, and Domino Stackings
No full textWe examine domino tilings of rectangular boards, which are in natural bijection with perfect matchings of grid graphs. This leads to the study of their associated perfect matching polytopes, and we present some of their properties, in particular, when these polytopes are Gorenstein. We also introduce the notion of domino stackings and present some results and several open questions. Our techniques use results from graph theory, polyhedral geometry, and enumerative combinatorics.National Science Foundation (U.S.) (NSF (DMS-0810105)Deutsche Forschungsgemeinschaft (DFG Emmy Noether fellowship HA 4383/1
Representations of rational Cherednik algebras of G(m,r,n) in positive characteristic
No full textWe study lowest-weight irreducible representations of rational Cherednik algebras attached to the complex reflection groups G(m,r,n) in characteristic p. Our approach is mostly from the perspective of commutative algebra. By studying the kernel of the contravariant bilinear form on Verma modules, we obtain formulas for a Hilbert series of irreducible representations in a number of cases, and present conjectures in other cases. We observe that the form of the Hilbert series of irreducible representations and the generators of the kernel tend to be determined by the value of n modulo p and are related to special classes of subspace arrangements. Perhaps the most novel (conjectural) discovery from the commutative algebra perspective is that the generators of the kernel can be given the structure of a "matrix regular sequence'' in some instances, which we prove in some small cases.American Society for Engineering Education. National Defense Science and Engineering Graduate FellowshipUniversity of California, Berkeley (Miller Research Fellowship
A Finite Calculus Approach to Ehrhart Polynomials
No full textA rational polytope is the convex hull of a finite set of points in R[superscript d] with rational coordinates. Given a rational polytope P⊆R[superscript d], Ehrhart proved that, for t∈Z≥[subscript 0[, the function #(tP∩Z[superscript d]) agrees with a quasi-polynomial L[subscript P](t), called the Ehrhart quasi-polynomial. The Ehrhart quasi-polynomial can be regarded as a discrete version of the volume of a polytope. We use that analogy to derive a new proof of Ehrhart's theorem. This proof also allows us to quickly prove two other facts about Ehrhart quasi-polynomials: McMullen's theorem about the periodicity of the individual coefficients of the quasi-polynomial and the Ehrhart–Macdonald theorem on reciprocity
Free resolutions, combinatorics, and geometry
No full textThesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Mathematics, 2012.This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.Cataloged from student submitted PDF version of thesis.Includes bibliographical references (p. 71-72).Boij-Söderberg theory is the study of two cones: the first is the cone of graded Betti tables over a polynomial ring, and the second is the cone of cohomology tables of coherent sheaves over projective space. Each cone has a triangulation induced from a certain partial order. Our first result gives a module-theoretic interpretation of this poset structure. The study of the cone of cohomology tables over an arbitrary polarized projective variety is closely related to the existence of an Ulrich sheaf, and our second result shows that such sheaves exist on the class of Schubert degeneracy loci. Finally, we consider the problem of classifying the possible ranks of Betti numbers for modules over a regular local ring.by Steven V Sam.Ph.D
In Loving Memory Of Ola V. Alcorn
No full textFuneral program for Ola V. Alcorn, born November 18, 1930 and died March 21, 2002. The funeral was held March 26, 2002 at Lilly of the Vally Missionary Baptist Church, officiated by Pastor Steven R. Owens, Sr. The funeral arrangements were made through Sutton's Paradise Funeral Home and she was buried in Fort Sam Houston National Cemetery near San Antonio, Texas
The effectiveness of interventions to treat severe acute malnutrition in young children: a systematic review
No full textSevere acute malnutrition (SAM) arises as a consequence of a sudden period of food shortage and is associated with loss of a person’s body fat and wasting of their skeletal muscle. Many of those affected are already undernourished and are often susceptible to disease. Infants and young children are the most vulnerable as they require extra nutrition for growth and development, have comparatively limited energy reserves and depend on others. Undernutrition can have drastic and wide-ranging consequences for the child’s development and survival in the short and long term. Despite efforts made to treat SAM through different interventions and programmes, it continues to cause unacceptably high levels of mortality and morbidity. Uncertainty remains as to the most effective methods to treat severe acute malnutrition in young children.ObjectivesTo evaluate the effectiveness of interventions to treat infants and children aged < 5 years who have SAM.Data sourcesEight databases (MEDLINE, EMBASE, MEDLINE In-Process & Other Non-Indexed Citations, CAB Abstracts Ovid, Bioline, Centre for Reviews and Dissemination, EconLit EBSCO and The Cochrane Library) were searched to 2010. Bibliographies of included articles and grey literature sources were also searched. The project expert advisory group was asked to identify additional published and unpublished references.Review methodsPrior to the systematic review, a Delphi process involving international experts prioritised the research questions. Searches were conducted and two reviewers independently screened titles and abstracts for eligibility. Inclusion criteria were applied to the full texts of retrieved papers by one reviewer and checked independently by a second. Included studies were mapped to the research questions. Data extraction and quality assessment were undertaken by one reviewer and checked by a second reviewer. Differences in opinion were resolved through discussion at each stage. Studies were synthesised through a narrative review with tabulation of the results.ResultsA total of 8954 records were screened, 224 full-text articles were retrieved, and 74 articles (describing 68 studies) met the inclusion criteria and were mapped. No evidence focused on treatment of children with SAM who were human immunodeficiency virus sero-positive, and no good-quality or adequately reported studies assessed treatments for SAM among infants < 6 months old. One randomised controlled trial investigated fluid resuscitation solutions for shock, with none adequately treating shock. Children with acute diarrhoea benefited from the use of hypo-osmolar oral rehydration solution (H-ORS) compared with the standard World Health Organization-oral rehydration solution (WHO-ORS). WHO-ORS was not significantly different from rehydration solution for malnutrition (ReSoMal), but the safety of ReSoMal was uncertain. A rice-based ORS was more beneficial than glucose-based ORSs, and provision of zinc plus a WHO-ORS had a favourable impact on diarrhoea and need for ORS. Comparisons of different diets in children with persistent diarrhoea produced conflicting findings. For treating infection, comparison of amoxicillin with ceftriaxone during inpatient therapy, and routine provision of antibiotics for 7 days versus no antibiotics during outpatient therapy of uncomplicated SAM, found that neither had a significant effect on recovery at the end of follow-up. No evidence mapped to the next three questions on factors that affect sustainability of programmes, long-term survival and readmission rates, the clinical effectiveness of management strategies for treating children with comorbidities such as tuberculosis and Helicobacter pylori infection and the factors that limit the full implementation of treatment programmes. Comparison of treatment for SAM in different settings showed that children receiving inpatient care appear to do as well as those in ambulatory or home settings on anthropometric measures and response time to treatment. Longer-term follow-up showed limited differences between the different settings. The majority of evidence on methods for correcting micronutrient deficiencies considered zinc supplements; however, trials were heterogeneous and a firm conclusion about zinc was not reached. There was limited evidence on either supplementary potassium or nicotinic acid (each produced some benefits), and nucleotides (not associated with benefits). Evidence was identified for four of the five remaining questions, but not assessed because of resource limitation.LimitationsThe systematic review focused on key questions prioritised through a Delphi study and, as a consequence, did not encompass all elements in the management of SAM. In focusing on evidence from controlled studies with the most rigorous designs that were published in the English language, the systematic review may have excluded other forms of evidence. The systematic review identified several limitations in the evidence base for assessing the effectiveness of interventions for treating young children with severe acute malnutrition, including a lack of studies assessing the different interventions; limited details of study methods used; short follow-up post intervention or discharge; and heterogeneity in participants, interventions, settings, and outcome measures affecting generalisability.ConclusionsFor many of the most highly ranked questions evidence was lacking or inconclusive. More research is needed on a range of topic areas concerning the treatment of infants and children with SAM. Further research is required on most aspects of the management of SAM in children < 5 years, including intravenous resuscitation regimens for shock, management of subgroups (e.g. infants < 6 months old, infants and children with SAM who are human immunodeficiency virus sero-positive) and on the use of antibiotics.FundingThe National Institute for Health Research Technology Assessment programme.<br/
Brief guide to senescence assays using cultured mammalian cells
No full textCellular senescence is a crucial biological process associated with organismal aging and many chronic diseases. Here, we present a brief guide to mammalian senescence assays, including the measurement of cell cycle arrest, change in cellular morphology, senescence-associated β-galactosidase (SA-β-gal) staining, and the expression of senescence-associated secretory phenotype (SASP). This work will be useful for biologists with minimum expertise in cellular senescence assays. © 2024 The Author(s)TRUEsciescopuskc
The ‘Galilean Style in Science’ and the Inconsistency of Linguistic Theorising
No full textChomsky’s principle of epistemological tolerance says that in theoretical linguistics contradictions between the data and the hypotheses may be temporarily tolerated in order to protect the explanatory power of the theory. The paper raises the following problem: What kinds of contradictions may be tolerated between the data and the hypotheses in theoretical linguistics? First a model of paraconsistent logic is introduced which differentiates between week and strong contradiction. As a second step, a case study is carried out which exemplifies that the principle of epistemological tolerance may be interpreted as the tolerance of week contradiction. The third step of the argumentation focuses on another case study which exemplifies that the principle of epistemological tolerance must not be interpreted as the tolerance of strong contradiction. The reason for the latter insight is the unreliability and the uncertainty of introspective data. From this finding the author draws the conclusion that it is the integration of different data types that may lead to the improvement of current theoretical linguistics and that the integration of different data types requires a novel methodology which, for the time being, is not available
“THE SON OF SAM” IN THE NEW YORK TIMES: CONTENT ANALYSIS RESULTS
No full textThe article aims at the study of the representation of serial killer David Berkowitz (The Son of Sam) in The New York Times using content analysis. The research includes all newspaper articles that have been published from the time of the first murder and until the judgment of the court. During the research the author analyzes not only exterior characteristics of the articles (genre, photographs, comments, etc.) but also interior characteristics created by the author (evaluative and descriptive elements, character properties). The author assumes that the newspaper intentionally or unintentionally creates an appealing image of the killer using different methods and linguistic techniques. Statistical data that we have obtained allow us to assert that the author`s hypothesis is confirmed. In particular, the author finds out that The New York Times journalists depict David Berkowitz as a worldwide celebrity and a mystic monster and endow him with supernatural properties and outstanding abilities. Such depiction has a great influence on the audience`s perception of the killer. Many examples of the killer`s psychological aggression in the newspaper allow us to assert that The New York Times is partly responsible for the panic in New York City during a yearlong Son of Sam shooting spree
Physical dance performance: An investigation into the development of a performance technique based on the integration of certain Korean dance technique and contemporary Western styles of dance and physical theatre
No full textThis thesis was submitted for the degree of Doctor of Philosophy and awarded by Brunel University, 04/10/2001.This development of a performer practice that integrates elements of traditional Korean dance technique and Western forms of physical theatre and contemporary dance is based on an approach to internal understanding and external execution. Central to the work is the concept of body energy, or Ki. This ancient Eastern term is translated into a contemporary practice that enables a performer to engage mental and physical training. Breath and the use of breath in performing are the principal means of achieving this level of engagement
- …
