8,970 research outputs found
Every longest circuit of a 3-connected, -minor free graph has a chord
Carsten Thomassen conjectured that every longest circuit in a 3-connected
graph has a chord. We prove the conjecture for graphs having no
minor, and consequently for planar graphs.Comment: accepted by Journal of Graph Theor
Let Care Shine Through
Care is in the eyes of the receiver; it doesn\u27t exist unless those being cared for experience it. The authors describe culturally relevant critical teacher care, an approach that considers the effects of students\u27 cultural and socioeconomic conditions and that helps teachers find ways to show care to every learnerâespecially those from oppressed groups. Bondy and Hambacher describe three principles of this care for students (having political clarity, embodying critical hope, and sticking to asset-based thinking). They describe four helpful practices that they observed in a long-term study of two effective 5th grade teachers. These teachers embodied a culturally relevant approach to supporting students: expanding the meaning of achievement; overhauling deficit thinking; offering high expectations and support; and teaching with urgency
Designing Redress: A Study About Grievances Against Public Bodies
How grievances against public bodies are resolved is important not only for the individuals concerned and the decision-makers complained about but also to the whole system of government. People need to have confidence that when things go wrong, they will be put right. There is a general public interest in that being done in accordance with constitutional principles and in ways that are effective and efficient. Over many years, a great variety of different ?mechanisms? for dealing with grievances have been created, ranging from internal complaints processes through to the work of external bodies (including ombudsmen, tribunals and courts). This project has focused on how mechanisms are designed. The study explores how different mechanisms can be thought of as relating to each other. It also looks at the various reasons why mechanisms have to be designed. Drawing on interviews with people involved in the design process and analysis of public information, a map of where the activity of designing redress has been created. Evaluating the ?administrative justice landscape?, two particular deficiencies emerge: there is no strong political or official leadership in relation to how mechanisms ought to be designed and the system is fragmented, with many different people, in various organisations all contributing to design activities. Might a toolkit of guiding principles for designing redress be one way of achieving a better design process and outcomes? A number of principles are proposed in this report, and the authors hope to engage stakeholders in a debate about how this might best be taken forward
Ore- and Fan-type heavy subgraphs for Hamiltonicity of 2-connected graphs
Bedrossian characterized all pairs of forbidden subgraphs for a 2-connected
graph to be Hamiltonian. Instead of forbidding some induced subgraphs, we relax
the conditions for graphs to be Hamiltonian by restricting Ore- and Fan-type
degree conditions on these induced subgraphs. Let be a graph on
vertices and be an induced subgraph of . is called \emph{o}-heavy if
there are two nonadjacent vertices in with degree sum at least , and is
called -heavy if for every two vertices ,
implies that . We say that is -\emph{o}-heavy
(-\emph{f}-heavy) if every induced subgraph of isomorphic to is
\emph{o}-heavy (\emph{f}-heavy). In this paper we characterize all connected
graphs and other than such that every 2-connected
-\emph{f}-heavy and -\emph{f}-heavy (-\emph{o}-heavy and
-\emph{f}-heavy, -\emph{f}-heavy and -free) graph is Hamiltonian. Our
results extend several previous theorems on forbidden subgraph conditions and
heavy subgraph conditions for Hamiltonicity of 2-connected graphs.Comment: 21 pages, 2 figure
Unique Breast Cancer Features Within the Vietnamese Population
BACKGROUND: Breast cancer is known to be a heterogeneous disease across women, and even within individual tumors. However, relatively little is known about heterogeneity across cultures. There has been some evidence to suggest that Asian women are more likely to have HER2+ breast cancer than their Caucasian counterparts.
PURPOSE: The aim of this study was to further investigate the unique pattern of breast cancer incidence and subtype in the Vietnamese population.
METHODS: We retrospectively collected data on all Vietnamese women diagnosed with invasive breast cancer at the Lester & Sue Smith Breast Center in Houston, Texas over a four year period. We recorded the subtype of breast cancer, tumor grade, age at diagnosis, and menopausal status for each woman. We then compared these characteristics between our population of Vietnamese breast cancer patients, and an ethnically diverse group of American women from the 2010 SEER registry.
RESULTS: We discovered that 15 of 33 Vietnamese patients diagnosed in our breast center had HER2 over-expressing breast cancer, resulting in a 45% rate of HER2 positivity. Compared with the 2010 Surveillance, Epidemiology, and End Results (SEER) registry data that encompasses 28% of all US breast cancer patients diagnosed that year, regardless of race, the Smith Clinic Vietnamese cohort had a statistically significant higher rate of HER2+ breast cancer, with an odds ratio of 4.7 (45% vs. 15%, p
CONCLUSIONS: Vietnamese breast cancer patients, especially those older than 50 years old, tend to have higher rates of HER2+ breast cancer than the general population. This unique pattern of breast cancer merits further study, as it may reflect a genetic mutation or environmental exposure which is more common among Vietnamese women
Gerechte Designs with Rectangular Regions
A \emph{gerechte framework} is a partition of an array into
regions of cells each. A \emph{realization} of a gerechte framework is a
latin square of order with the property that when its cells are partitioned
by the framework, each region contains exactly one copy of each symbol. A
\emph{gerechte design} is a gerechte framework together with a realization.
We investigate gerechte frameworks where each region is a rectangle. It seems
plausible that all such frameworks have realizations, and we present some
progress towards answering this question. In particular, we show that for all
positive integers and , any gerechte framework where each region is
either an rectangle or a rectangle is realizable.Comment: 14 pages, 12 figure
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Distinctive cellular response to aluminum based adjuvants.
Aluminum-based adjuvants (ABAs) are used in human vaccines to enhance the magnitude of protective immune responses elicited against specific pathogens. One hypothesis is that stress signals released by aluminum-exposed necrotic cells play a role in modulating an immune response that contributes to the adjuvant's effectiveness. We hypothesized that aluminum adjuvant-induced necrosis would be similar irrespective of cellular origin or composition of the adjuvant. To test this hypothesis, human macrophages derived from peripheral monocytic cell line (THP-1) and cells derived from the human brain (primary astrocytes) were evaluated. Three commercially available formulations of ABAs (Alhydrogel, Imject alum, and Adju-Phos) were examined. Alum was also used as a reference. Cell viability, reactive oxygen species formation, and production of tumor necrosis factor alpha (TNF-α) and interleukin-6 (IL-6) were quantified. Cells were exposed to different concentrations (10-100 Όg/mL) of the adjuvants for 24 h or 72 h. The two FDA approved adjuvants (Alhydrogel and Adju-Phos) decreased cell viability in both cell types. At the 72 h time point, the decrease in viability was accompanied with increased ROS formation. The size of the aluminum agglomerates was not relatable to the changes observed. After exposure to ABAs, astrocytes and macrophages presented a distinct profile of cytokine secretion which may relate to the function and unique characteristics of each cell type. These variations indicate that aluminum adjuvants may have differing capability of activating cells of different origin and thus their utility in specific vaccine design should be carefully assessed for optimum efficacy
The epistemic approach to argument evaluation: Virtues, beliefs, commitments
This paper will have two parts. In the first, it will point out the agreement between lists of paradigm epistemic and argumentative virtues, and it will take that agreement as prima facie support for the epistemic approach to argument evaluation. Second, it will consider the disagreement over whether successful argument resolution requires change of belief or whether it only requires change of commitment. It turns out that the epistemic approach is neutral on that question
Becoming warm demanders: Perspectives and practices of first-year teachers
In the literature on culturally responsive pedagogy warm demanders are teachers who embrace values and enact practices that are central to their studentsâ success. Few scholars have examined the experience of novice teachers who attempt to enact this stance. In this study of two first-year, female, European American teachers who attempted to be warm demanders for their predominantly African American elementary school students, the authors answer the question, âHow do the teachers think about and enact warm demanding?â The teachersâ contrasting experiences have implications for administrators and teacher educators
Tutte's 5-Flow Conjecture for Highly Cyclically Connected Cubic Graphs
In 1954, Tutte conjectured that every bridgeless graph has a nowhere-zero
5-flow. Let be the minimum number of odd cycles in a 2-factor of a
bridgeless cubic graph. Tutte's conjecture is equivalent to its restriction to
cubic graphs with . We show that if a cubic graph has no
edge cut with fewer than edges that separates two odd
cycles of a minimum 2-factor of , then has a nowhere-zero 5-flow. This
implies that if a cubic graph is cyclically -edge connected and , then has a nowhere-zero 5-flow
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