pinecone/core-2020-05-10-deduplication huggingface dataset:
Dynamic choosability of triangle-free graphs and sparse random graphs

The \textit{$r$-dynamic choosability} of a graph $G$, written ${\rm
ch}_r(G)$, is the least $k$ such that whenever each vertex is assigned a list
of at least $k$ colors a proper coloring can be chosen from the lists so that
every vertex $v$ has at least $\min\{d_G(v),r\}$ neighbors of distinct colors.
Let ${\rm ch}(G)$ denote the choice number of $G$. In this paper, we prove
${\rm ch}_r(G)\leq (1+o(1)){\rm ch}(G)$ when $\frac{\Delta(G)}{\delta(G)}$ is
bounded. We also show that there exists a constant $C$ such that for the random
graph $G=G(n,p)$ with $\frac{2}{n}<p\leq \frac{1}{2}$, it holds that ${\rm
ch}_2(G)\leq {\rm ch}(G) + C$, asymptotically almost surely. Also if $G$ is
triangle-free regualr graph, then ${\rm ch}_2(G)\leq {\rm ch}(G)+86$ holds
Convex drawings of the complete graph: topology meets geometry

In this work, we introduce and develop a theory of convex drawings of the
complete graph $K_n$ in the sphere. A drawing $D$ of $K_n$ is convex if, for
every 3-cycle $T$ of $K_n$, there is a closed disc $\Delta_T$ bounded by $D[T]$
such that, for any two vertices $u,v$ with $D[u]$ and $D[v]$ both in
$\Delta_T$, the entire edge $D[uv]$ is also contained in $\Delta_T$.
  As one application of this perspective, we consider drawings containing a
non-convex $K_5$ that has restrictions on its extensions to drawings of $K_7$.
For each such drawing, we use convexity to produce a new drawing with fewer
crossings. This is the first example of local considerations providing
sufficient conditions for suboptimality. In particular, we do not compare the
number of crossings {with the number of crossings in} any known drawings. This
result sheds light on Aichholzer's computer proof (personal communication)
showing that, for $n\le 12$, every optimal drawing of $K_n$ is convex.
  Convex drawings are characterized by excluding two of the five drawings of
$K_5$. Two refinements of convex drawings are h-convex and f-convex drawings.
The latter have been shown by Aichholzer et al (Deciding monotonicity of good
drawings of the complete graph, Proc.~XVI Spanish Meeting on Computational
Geometry (EGC 2015), 2015) and, independently, the authors of the current
article (Levi's Lemma, pseudolinear drawings of $K_n$, and empty triangles,
\rbr{J. Graph Theory DOI: 10.1002/jgt.22167)}, to be equivalent to pseudolinear
drawings. Also, h-convex drawings are equivalent to pseudospherical drawings as
demonstrated recently by Arroyo et al (Extending drawings of complete graphs
into arrangements of pseudocircles, submitted)
Finding a subdivision of a prescribed digraph of order 4

The problem of when a given digraph contains a subdivision of a fixed digraph
$F$ is considered. Bang-Jensen et al. laid out foundations for approaching this
problem from the algorithmic point of view. In this paper we give further
support to several open conjectures and speculations about algorithmic
complexity of finding $F$-subdivisions. In particular, up to 5 exceptions, we
completely classify for which 4-vertex digraphs $F$, the $F$-subdivision
problem is polynomial-time solvable and for which it is NP-complete. While all
NP-hardness proofs are made by reduction from some version of the 2-linkage
problem in digraphs, some of the polynomial-time solvable cases involve
relatively complicated algorithms.Comment: To appear in Journal of Graph Theor
Polychromatic colorings of complete graphs with respect to 1-,2-factors
  and Hamiltonian cycles

If G is a graph and H is a set of subgraphs of G, then an edge-coloring of G
is called H-polychromatic if every graph from H gets all colors present in G on
its edges. The H-polychromatic number of G, denoted poly_H(G), is the largest
number of colors in an H-polychromatic coloring. In this paper, poly_H(G) is
determined exactly when G is a complete graph and H is the family of all
1-factors. In addition poly_H(G) is found up to an additive constant term when
G is a complete graph and H is the family of all 2-factors, or the family of
all Hamiltonian cycles.Comment: 15 pages, 6 figure
Circuit Covers of Cubic Signed Graphs

A signed graph is a graph $G$ associated with a mapping $\sigma: E(G)\to
\{-1,+1\}$, denoted by $(G,\sigma)$. A $cycle$ of $(G,\sigma)$ is a connected
2-regular subgraph. A cycle $C$ is $positive$ if it has an even number of
negative edges, and negative otherwise. A $circuit$ of of a signed graph
$(G,\sigma)$ is a positive cycle or a barbell consisting of two edge-disjoint
negative cycles joined by a path. The definition of a circuit of signed graph
comes from the signed-graphic matroid. A circuit cover of $(G,\sigma)$ is a
family of circuits covering all edges of $(G,\sigma)$. A circuit cover with the
smallest total length is called a shortest circuit cover of $(G,\sigma)$ and
its length is denoted by $\text{scc}(G,\sigma)$. Bouchet proved that a signed
graph with a circuit cover if and only if it is flow-admissible (i.e., has a
nowhere-zero integer flow). M\'a\v{c}ajov\'a et. al. show that a
2-edge-connected signed graph $(G,\sigma)$ has $\text{scc}(G,\sigma)\le 9
|E(G)|$ if it is flow-admissible. This bound was improved recently by Cheng et.
al. to $\text{scc}(G,\sigma) \le 11|E(G)|/3$ for 2-edge-connected signed graphs
with even negativeness, and particularly, $\text{scc}(G,\sigma)\le
3|E(G)|+\epsilon(G,\sigma)/3$ for 2-edge-connected cubic signed graphs with
even negativeness (where $\epsilon(G,\sigma)$ is the negativeness of
$(G,\sigma)$). In this paper, we show that every 2-edge-connected cubic signed
graph has $\text{scc}(G,\sigma)\le 26|E(G)|/9$ if it is flow-admissible, and
$\text{scc}(G,\sigma)\le 23|E(G)|/9$ if it has even negativeness.Comment: 13 pages, 2 figure
The width of quadrangulations of the projective plane

We show that every $4$-chromatic graph on $n$ vertices, with no two
vertex-disjoint odd cycles, has an odd cycle of length at most
$\tfrac12\,(1+\sqrt{8n-7})$. Let $G$ be a non-bipartite quadrangulation of the
projective plane on $n$ vertices. Our result immediately implies that $G$ has
edge-width at most $\tfrac12\,(1+\sqrt{8n-7})$, which is sharp for infinitely
many values of $n$. We also show that $G$ has face-width (equivalently,
contains an odd cycle transversal of cardinality) at most $\tfrac14(1+\sqrt{16
n-15})$, which is a constant away from the optimal; we prove a lower bound of
$\sqrt{n}$. Finally, we show that $G$ has an odd cycle transversal of size at
most $\sqrt{2\Delta n}$ inducing a single edge, where $\Delta$ is the maximum
degree. This last result partially answers a question of Nakamoto and Ozeki.Comment: 15 pages, 4 figures (revised version
Koml\'os's tiling theorem via graphon covers

Komlos [Komlos: Tiling Turan Theorems, Combinatorica, 2000] determined the
asymptotically optimal minimum-degree condition for covering a given proportion
of vertices of a host graph by vertex-disjoint copies of a fixed graph H, thus
essentially extending the Hajnal-Szemeredi theorem which deals with the case
when H is a clique. We give a proof of a graphon version of Komlos's theorem.
To prove this graphon version, and also to deduce from it the original
statement about finite graphs, we use the machinery introduced in [Hladky, Hu,
Piguet: Tilings in graphons, arXiv:1606.03113]. We further prove a stability
version of Komlos's theorem.Comment: 21 pages, 1 figure; accepted to Journal of Graph Theor
Improper coloring of graphs on surfaces

A graph $G$ is $(d_1,\ldots,d_k)$-colorable if its vertex set can be
partitioned into $k$ sets $V_1,\ldots,V_k$, such that for each $i\in\{1,
\ldots, k\}$, the subgraph of $G$ induced by $V_i$ has maximum degree at most
$d_i$. The Four Color Theorem states that every planar graph is
$(0,0,0,0)$-colorable, and a classical result of Cowen, Cowen, and Woodall
shows that every planar graph is $(2,2,2)$-colorable. In this paper, we extend
both of these results to graphs on surfaces. Namely, we show that every graph
embeddable on a surface of Euler genus $g>0$ is $(0,0,0,9g-4)$-colorable and
$(2,2,9g-4)$-colorable. Moreover, these graphs are also
$(0,0,O(\sqrt{g}),O(\sqrt{g}))$-colorable and
$(2,O(\sqrt{g}),O(\sqrt{g}))$-colorable. We also prove that every triangle-free
graph that is embeddable on a surface of Euler genus $g$ is $(0, 0,
O(g))$-colorable. This is an extension of Gr\"{o}tzsch's Theorem, which states
that triangle-free planar graphs are $(0, 0, 0)$-colorable. Finally, we prove
that every graph of girth at least 7 that is embeddable on a surface of Euler
genus $g$ is $(0,O(\sqrt{g}))$-colorable. All these results are best possible
in several ways as the girth condition is sharp, the constant maximum degrees
cannot be improved, and the bounds on the maximum degrees depending on $g$ are
tight up to a constant multiplicative factor.Comment: 19 pages, 3 figures - v3 - final versio
On dihedral flows in embedded graphs

Let $\Gamma$ be a multigraph with for each vertex a cyclic order of the edges
incident with it. For $n \geq 3$, let $D_{2n}$ be the dihedral group of order
$2n$. Define $\mathbb{D} := \{(\begin{smallmatrix} 1 & a \\ 0 & 1
\end{smallmatrix}) \mid a \in \mathbb{Z}\}$. In [5] it was asked whether
$\Gamma$ admits a nowhere-identity $D_{2n}$-flow if and only if it admits a
nowhere-identity $\mathbb{D}$-flow with $|a| < n$ (a `nowhere-identity
$\mathbb{D}_n$-flow'). We give counterexamples to this statement and provide
general obstructions. Furthermore, the complexity of the existence of
nowhere-identity $\mathbb{D}_2$-flows is discussed. Lastly, graphs in which the
equivalence of the existence of flows as above is true, are described. We focus
particularly on cubic graphs.Comment: 16 pages. Some changes have been made, based on comments of the
  referees. Accepted for publication in Journal of Graph Theor
Preoperative intramuscular adipose tissue content is a novel prognostic predictor after hepatectomy for hepatocellular carcinoma.

[Background] Sarcopenia has been shown to be an independent predictor of lower disease-free and overall survival in various kinds of diseases. The quality of skeletal muscle has recently attracted much attention as a new parameter of sarcopenia. [Methods] We performed a retrospective analysis of 477 patients undergoing hepatectomy for hepatocellular carcinoma (HCC) between April 2005 and August 2014. The quality of skeletal muscle was evaluated by intramuscular adipose tissue content (IMAC) using preoperative computed tomography (CT) imaging. The impact of IMAC on outcomes after hepatectomy for HCC was analyzed. [Results] Patients with high IMAC showed older age, higher body mass index, higher indocyanine green retention test at 15 min, and more operative blood loss. The overall and recurrence-free survival rates were significantly lower in patients with high IMAC than in patients with normal IMAC (P < 0.0001, P = 0.0012, respectively). Multivariate analysis showed that high IMAC was the significant risk factor for death (hazard ratio [HR] = 2.942; P < 0.0001) and for HCC recurrence (HR = 1.529; P = 0.0007) after hepatectomy. [Conclusions] Preoperative quality of skeletal muscle was closely correlated with postoperative mortality and HCC recurrence. IMAC could be incorporated into new selection criteria for hepatectomy for HCC
Molecular mechanism of intraductal papillary mucinous neoplasm and intraductal papillary mucinous neoplasm-derived pancreatic ductal adenocarcinoma.

Pancreatic ductal adenocarcinoma (PDA) is one of the most lethal human malignancies. Dissecting the mechanisms underlying PDA development is important for developing early detection methods and effective prevention and therapies for the disease. PDA is considered to arise from distinct precursor lesions, including pancreatic intraepithelial neoplasia (PanIN) and intraductal papillary mucinous neoplasia (IPMN). However, little is known about molecular mechanisms of development of IPMN and IPMN-derived PDA. We have recently reported that loss of Brg1, a core subunit of SWI/SNF chromatin remodeling complexes, cooperates with oncogenic Kras to form cystic neoplastic lesions that resemble human IPMN and progress to PDA. Brg1 null IPMN-PDA is less lethal compared to PanIN-derived PDA (PanIN-PDA) driven by mutant Kras and hemizygous p53 deletion, mirroring prognostic trends in PDA patients. Brg1 null IPMN-PDA possesses a distinct molecular signature that supports less malignant potential compared to PanIN-PDA. Furthermore, Brg1 deletion inhibits Kras-dependent PanIN development from adult acinar cells, but promotes Kras-driven preneoplastic transformation in adult duct cells. Therefore, Brg1 is a determinant of context-dependent Kras-driven pancreatic tumorigenesis and chromatin remodeling may underlie the development of distinct PDA subsets. Understanding molecular mechanism of IPMN and IPMN-derived PDA could provide critical clues for novel diagnostic and therapeutic strategies of the disease
V. M. Bekhterev in Russian child science, 1900s-1920s :  “objective psychology” / “reflexology” as a scientific movement.\ud

In the early 20th century the child population became a major focus of scientific, professional and public interest. This led to the crystallization of a dynamic field of child science, encompassing developmental and educational psychology, child psychiatry and special education, school hygiene and mental testing, juvenile criminology and the anthropology of childhood. This article discusses the role played in child science by the eminent Russian neurologist and psychiatrist Vladimir Mikhailovich Bekhterev. The latter's name is associated with a distinctive program for transforming the human sciences in general and psychology in particular that he in the 1900s labelled “objective psychology” and from the 1910s renamed “reflexology.” The article examines the equivocal place that Bekhterev's “objective psychology” and “reflexology” occupied in Russian/Soviet child science in the first three decades of the 20th century. While Bekhterev's prominence in this field is beyond doubt, analysis shows that “objective psychology” and “reflexology” had much less success in mobilizing support within it than certain other movements in this arena (for example, “experimental pedagogy” in the pre-revolutionary era); it also found it difficult to compete with the variety of rival programs that arose within Soviet “pedology” during the 1920s. However, this article also demonstrates that the study of child development played a pivotal role in Bekhterev's program for the transformation of the human sciences: it was especially important to his efforts to ground in empirical phenomena and in concrete research practices a new ontology of the psychological, which, the article argues, underpinned “objective psychology”/“reflexology” as a transformative scientific movement
Impact of an Inpatient Geriatric Consultative Service on Outcomes for Cognitively Impaired Patients

Background

Impact of geriatric consultative services (GCS) on hospital readmission and mortality outcomes for cognitively impaired (CI) patients is not known.
Objective

Evaluate impact of GCS on hospital readmission and mortality among CI inpatients.
Design

Secondary data-analysis of a prospective trial of a computerized decision support system between July 1, 2006, and May 30, 2008.
Setting

Study conducted at XXXXX hospital, a 340-bed, public hospital with over 2,300 yearly admissions of 65 or older.
Patients

415 inpatients aged 65 and older with CI were enrolled from July 2006 to March 2008.
Measurements

30 day and one year mortality and hospital readmission following the index admission. Cox’s proportional hazard models were used to determine the association between receiving GCS, re-admission or mortality while adjusting for demographics, discharge destination, delirium, Charlson Comorbidity Index, and prior hospitalizations. The propensity score method was used to adjust for the non-random assignment of GCS.
Results

Patients receiving GCS were older (79; 8.1 SD vs 76; 7.8 SD; p<.001 with higher incidence of delirium (49% vs. 29%; p<.001)). No significant differences were found between the groups for hospital readmission (Hazard Ratio (HR)=1.19; 95% CI = 0.89, 1.59) and mortality at 12 months of index admission (HR=.91 ; 95% CI = 0.59, 1.40). However, a significant increase in readmissions was observed for the GCS group (HR=1.75; 95% CI = 1.06–2.88) at 30 days post-discharge.
Conclusion

One year post-discharge outcomes of CI patients that received GCS were not different from patients who did not receive the service. New models of care are needed to improve post-discharge readmission and mortality among hospitalized patients with CI
Navigating venous access: A guide for hospitalists

Venous access is the foundation for safe and effective hospital-based care. Inpatient providers must have a deep knowledge of the different types of venous access devices (VADs), their relative indications, contraindications, and appropriateness. However, such knowledge is difficult to come by and usually only gleaned through years of clinical experience. To bridge this gap, we provide an in-depth summary of the relevant anatomical considerations, physical characteristics, advantages, and disadvantages of VADs commonly used in the hospital setting. In doing so, we seek to improve the safety and share the science of vascular access with frontline clinicians. To aid decision-making, we conclude by operationalizing the available data through algorithms that outline appropriate vascular access for the hospitalized patient.Full Tex
Redesigning inpatient care: testing the effectiveness of an Accountable Care Team model

BACKGROUND
US healthcare underperforms on quality and safety metrics. Inpatient care constitutes an immense opportunity to intervene to improve care.

OBJECTIVE
Describe a model of inpatient care and measure its impact.

DESIGN
A quantitative assessment of the implementation of a new model of care. The graded implementation of the model allowed us to follow outcomes and measure their association with the dose of the implementation.

SETTING AND PATIENTS
Inpatient medical and surgical units in a large academic health center.

INTERVENTION
Eight interventions rooted in improving interprofessional collaboration (IPC), enabling data-driven decisions, and providing leadership were implemented.

MEASUREMENTS
Outcome data from August 2012 to December 2013 were analyzed using generalized linear mixed models for associations with the implementation of the model. Length of stay (LOS) index, case-mix index–adjusted variable direct costs (CMI-adjusted VDC), 30-day readmission rates, overall patient satisfaction scores, and provider satisfaction with the model were measured.

RESULTS
The implementation of the model was associated with decreases in LOS index (P < 0.0001) and CMI-adjusted VDC (P = 0.0006). We did not detect improvements in readmission rates or patient satisfaction scores. Most providers (95.8%, n = 92) agreed that the model had improved the quality and safety of the care delivered.

CONCLUSIONS
Creating an environment and framework in which IPC is fostered, performance data are transparently available, and leadership is provided may improve value on both medical and surgical units. These interventions appear to be well accepted by front-line staff. Readmission rates and patient satisfaction remain challenging
Trends in Thrombolytic Use for Ischemic Stroke in the United States

BACKGROUND: Although recombinant tissue plasminogen activator (tPA) improves outcomes from ischemic stroke, prior studies have found low rates of administration. Recent guidelines and regulatory agencies have advocated for increased tPA administration in appropriate patients, but it is unclear how many patients actually receive tPA. OBJECTIVE: To determine whether national rates of tPA use for ischemic stroke have increased over time. METHODS: We identified all patients with a primary diagnosis of ischemic stroke from years 2001 to 2006 in the National Hospital Discharge Survey (NHDS), a nationally representative sample of inpatient hospitalizations, and searched for procedure codes for intravenous thrombolytic administration. Clinical and demographic factors were obtained from the survey and multivariable logistic regression used to identify independent predictors associated with thrombolytic use. RESULTS: Among the 22,842 patients hospitalized with ischemic stroke, tPA administration rates increased from 0.87% in 2001 to 2.40% in 2006 (P < 0.001 for trend). Older patients were less likely to receive tPA (adjusted odds ratio [OR] and 95% confidence interval [CI]; 0.4 [0.3-0.6] for patients ≥80 years vs. <60 years), as were African American patients (0.4 [0.3-0.7]). Larger hospitals were more likely to administer tPA (3.3 [2.0-5.6] in hospitals with at least 300 beds compared to those with 6-99 beds). CONCLUSIONS: Although tPA administration for ischemic stroke has increased nationally in recent years, the overall rate of use remains very low. Larger hospitals were more likely to administer tPA. Further efforts to improve appropriate administration of tPA should be encouraged, particularly as the acceptable time-window for using tPA widens.Economic
Differences in designations of observation care in US freestanding children's hospitals: Are they virtual or real?

OBJECTIVE:  To characterize practices related to observation care and to examine the current models of pediatric observation medicine in US children's hospitals.    DESIGN:  We utilized 2 web‐based surveys to examine observation care in the 42 hospitals participating in the Pediatric Health Information System database. We obtained information regarding the designation of observation status, including the criteria used to admit patients into observation. From hospitals reporting the use of observation status, we requested specific details relating to the structures of observation care and the processes of care for observation patients following emergency department treatment.    RESULTS:  A total of 37 hospitals responded to Survey 1, and 20 hospitals responded to Survey 2. Designated observation units were present in only 12 of 31 (39%) hospitals that report observation patient data to the Pediatric Health Information System. Observation status was variably defined in terms of duration of treatment and prespecified criteria. Observation periods were limited to <48 hours in 24 of 31 (77%) hospitals. Hospitals reported that various standards were used by different payers to determine observation status reimbursement. Observation care was delivered in a variety of settings. Most hospitals indicated that there were no differences in the clinical care delivered to virtual observation status patients when compared with other inpatients.    CONCLUSIONS:  Observation is a variably applied patient status, defined differently by individual hospitals. Consistency in the designation of patients under observation status among hospitals and payers may be necessary to compare quality outcomes and costs, as well as optimize models of pediatric observation care. Journal of Hospital Medicine  2012;. © 2011 Society of Hospital Medicine