bluuebunny/crossref_metadata_2025_split huggingface dataset:
Spanning Trails in a 2-Connected Graph
Authors: Wang Shipeng , Xiong Liming 
Published: January 2020

In this article we prove the following: Let $G$ be a $2$-connected graph with circumference $c(G)$. If $c(G)\leq 5$, then $G$ has a spanning trail starting from any vertex, if $c(G)\leq 7$, then $G$ has a spanning trail.
As applications of this result, we obtain the following.

Every $2$-edge-connected graph of order at most 8 has a spanning trail starting from any vertex with the exception of six graphs.

Let $G$ be a $2$-edge-connected graph and $S$ a subset of $V(G)$ such that $E(G-S)=\emptyset$ and $|S|\leq 6$. Then $G$ has a trail traversing all vertices of $S$ with the exception of two graphs, moreover, if $|S|\leq 4$, then $G$ has a trail starting from any vertex of $S$ and containing $S$.

Every $2$-connected claw-free graph $G$ with order $n$ and minimum degree $\delta(G)> \frac{n}{7}+4\geq 23$ is traceable or belongs to two exceptional families of well-defined graphs, and moreover, if $\delta(G)> \frac{n}{6}+4\geq 13$, then $G$ is traceable.

All above results are sharp in a sense.
Classes of Graphs with $e$-Positive Chromatic Symmetric Function
Authors: Foley Angèle M. , Hoàng Chính T. , Merkel Owen D. 
Published: January 2020

In the mid-1990s, Stanley and Stembridge conjectured that the chromatic symmetric functions of claw-free co-comparability (also called incomparability) graphs were $e$-positive. The quest for the proof of this conjecture has led to an examination of other, related graph classes. In 2013 Guay-Paquet proved that if unit interval graphs are $e$-positive, that implies claw-free incomparability graphs are as well. Inspired by this approach, we consider a related case and prove that unit interval graphs whose complement is also a unit interval graph are $e$-positive. We introduce the concept of strongly $e$-positive to denote a graph whose induced subgraphs are all $e$-positive, and conjecture that a graph is strongly $e$-positive if and only if it is (claw, net)-free.
Flow polynomials of a Signed Graph
Authors: Ren Xiangyu , Qian Jianguo 
Published: January 2020

For a signed graph $G$ and non-negative integer $d$, it was shown by DeVos et al. that there exists a polynomial $F_d(G,x)$ such that the number of the nowhere-zero $\Gamma$-flows in $G$ equals $F_d(G,x)$ evaluated at $k$ for every Abelian group $\Gamma$ of order $k$ with $\epsilon(\Gamma)=d$, where $\epsilon(\Gamma)$ is the largest integer $d$ for which $\Gamma$ has a subgroup isomorphic to $\mathbb{Z}^d_2$. We define a class of particular directed circuits in $G$, namely the fundamental directed circuits, and show that all $\Gamma$-flows (not necessarily nowhere-zero) in $G$ can be generated by these circuits. It turns out that all $\Gamma$-flows in $G$ can be evenly partitioned into $2^{\epsilon(\Gamma)}$ classes specified by the elements of order 2 in $\Gamma$, each class of which consists of the same number of flows depending only on the order of $\Gamma$. Using an extension of Whitney's broken circuit theorem of Dohmen and Trinks, we give a combinatorial interpretation of the coefficients in $F_d(G,x)$ for $d=0$ in terms of broken bonds. Finally, we show that the sets of edges in a signed graph that contain no broken bond form a homogeneous simplicial complex.
Resilient Degree Sequences with respect to Hamilton Cycles and Matchings in Random Graphs
Authors: Condon Padraig , Espuny Díaz Alberto , Kühn Daniela , Osthus Deryk , Kim Jaehoon 
Published: January 2020

Pósa's theorem states that any graph $G$ whose degree sequence $d_1 \le \cdots \le d_n$ satisfies $d_i \ge i+1$ for all $i < n/2$ has a Hamilton cycle. This degree condition is best possible. We show that a similar result holds for suitable subgraphs $G$ of random graphs, i.e.~we prove a `resilience version' of Pósa's theorem: if $pn \ge C \log n$ and the $i$-th vertex degree (ordered increasingly) of $G \subseteq G_{n,p}$ is at least $(i+o(n))p$ for all $i<n/2$, then $G$ has a Hamilton cycle. This is essentially best possible and strengthens a resilience version of Dirac's theorem obtained by Lee and Sudakov.
Chvátal's theorem generalises Pósa's theorem and characterises all degree sequences which ensure the existence of a Hamilton cycle. We show that a natural guess for a resilience version of Chvátal's theorem fails to be true. We formulate a conjecture which would repair this guess, and show that the corresponding degree conditions ensure the existence of a perfect matching in any subgraph of $G_{n,p}$ which satisfies these conditions. This provides an asymptotic characterisation of all degree sequences which resiliently guarantee the existence of a perfect matching.
Cyclic Demazure Modules and Positroid Varieties
Authors: Lam Thomas 
Published: January 2020

A positroid variety is an intersection of cyclically rotated Grassmannian Schubert varieties. Each graded piece of the homogeneous coordinate ring of a positroid variety is the intersection of cyclically rotated (rectangular) Demazure modules, which we call the cyclic Demazure module. In this note, we show that the cyclic Demazure module has a canonical basis, and define the cyclic Demazure crystal.
Generalised Mycielski Graphs and the Borsuk–Ulam Theorem
Authors: Müller Tobias , Stehlík Matěj 
Published: January 2020

Stiebitz determined the chromatic number of generalised Mycielski graphs using the topological method of Lovász, which invokes the Borsuk–Ulam theorem. Van Ngoc and Tuza used elementary combinatorial arguments to prove Stiebitz's theorem for 4-chromatic generalised Mycielski graphs, and asked if there is also an elementary combinatorial proof for higher chromatic number. We answer their question by showing that Stiebitz's theorem can be deduced from a version of Fan's combinatorial lemma. Our proof uses topological terminology, but is otherwise completely discrete and could be rewritten to avoid topology altogether. However, doing so would be somewhat artificial, because we also show that Stiebitz's theorem is equivalent to the Borsuk–Ulam theorem.
The Spectrum of Group-Based Complete Latin Squares
Authors: Ollis M. A. , Tripp Christopher R. 
Published: January 2020

We construct sequencings for many groups that are a semi-direct product of an odd-order abelian group and a cyclic group of odd prime order. It follows from these constructions that there is a group-based complete Latin square of order $n$ if and only if $n \in \{ 1,2,4\}$ or there is a non-abelian group of order $n$.
On Partially Ordered Patterns of Length 4 and 5 in Permutations
Authors: Gao Alice L. L. , Kitaev Sergey 
Published: January 2020

Partially ordered patterns (POPs) generalize the notion of classical patterns studied widely in the literature in the context of permutations, words, compositions and partitions. In an occurrence of a POP, the relative order of some of the elements is not important. Thus, any POP of length $k$ is defined by a partially ordered set on $k$ elements, and classical patterns correspond to $k$-element chains. The notion of a POP provides a convenient language to deal with larger sets of permutation patterns.
This paper contributes to a long line of research on classical permutation patterns of length 4 and 5, and beyond, by conducting a systematic search of connections between sequences in the Online Encyclopedia of Integer Sequences (OEIS) and permutations avoiding POPs of length 4 and 5. As the result, we (i) obtain 13 new enumerative results for classical patterns of length 4 and 5, and a number of results for patterns of arbitrary length, (ii) collect under one roof many sporadic results in the literature related to avoidance of patterns of length 4 and 5, and (iii) conjecture 6 connections to the OEIS. Among the most intriguing bijective questions we state, 7 are related to explaining Wilf-equivalence of various sets of patterns, e.g. 5 or 8 patterns of length 4, and 2 or 6 patterns of length 5.
The Toucher-Isolator game
Authors: Dowden Chris , Kang Mihyun , Mikalački Mirjana , Stojaković Miloš 
Published: January 2020

We introduce a new positional game called `Toucher-Isolator', which is a quantitative version of a Maker-Breaker type game. The playing board is the set of edges of a given graph $G$, and the two players, Toucher and Isolator, claim edges alternately. The aim of Toucher is to `touch' as many vertices as possible (i.e. to maximise the number of vertices that are incident to at least one of her chosen edges), and the aim of Isolator is to minimise the number of vertices that are so touched.
We analyse the number of untouched vertices $u(G)$ at the end of the game when both Toucher and Isolator play optimally, obtaining results both for general graphs and for particularly interesting classes of graphs, such as cycles, paths, trees, and $k$-regular graphs. We also provide tight examples.
Fractional Domination Game
Authors: Bujtas Csilla , Tuza Zsolt 
Published: January 2020

Given a graph $G$, a real-valued function $f: V(G) \rightarrow [0,1]$ is a fractional dominating function if $\sum_{u \in N[v]} f(u) \ge 1$ holds for every vertex $v$ and its closed neighborhood $N[v]$ in $G$. The aim is to minimize the sum $\sum_{v \in V(G)} f(v)$.
A different approach to graph domination is the domination game, introduced by Brešar et al. [SIAM J. Discrete Math. 24 (2010) 979–991]. It is played on a graph $G$ by two players, namely Dominator and Staller, who take turns choosing a vertex such that at least one previously undominated vertex becomes dominated. The game is over when all vertices are dominated. Dominator wants to finish the game as soon as possible, while Staller wants to delay the end. Assuming that both players play optimally and Dominator starts, the length of the game on $G$ is uniquely determined and is called the game domination number of $G$.
We introduce and study the fractional version of the domination game, where the moves are ruled by the condition of fractional domination. Here we prove a fundamental property of this new game, namely the fractional version of the so-called Continuation Principle. Moreover, we present lower and upper bounds on the fractional game domination number of paths and cycles. These estimates are tight apart from a small additive constant. We also prove that the game domination number cannot be bounded above by any linear function of the fractional game domination number.
Implementasi Peraturan Presiden Nomor 70 Tahun 2012 Tentang Pengadaan Barang / Layanan Oleh Unit Elektronik (E-Pengadaan) Pada Layanan Pengadaan (ULP) Universitas Lampung
Authors: Ngadiman Ngadiman 
Published: January 2020

Penelitian ini bertujuan untuk melihat implementasi kebijakan dan kendala pada proses komunikasi, sumber daya, disposisi dan struktur birokrasi dalam pelaksanaan pengadaan barang / jasa berbasis elektronik (eprocurement). Penelitian ini menggunakan metode deskriptif dengan pendekatan kualitatif. Data dikumpulkan melalui studi wawancara mendalam, dokumentasi dan observasi, sedangkan teknik validitas data dilakukan melalui triangulasi, termasuk metode triangulasi, sumber data dan data itu sendiri. Hasil penelitian ini menunjukkan bahwa e-procurement telah menunjukkan keberhasilan mereka, meskipun belum optimal, yang memperoleh efisiensi dan efektifitas pada sejumlah indikator. Dari aspek waktu, proses pengadaan dengan sistem e-procurement terbukti lebih cepat karena hanya membutuhkan waktu 14-18 hari kerja, sistem konvensional yang membutuhkan lebih dari 30 hari kerja melalui e-procurement dapat mengurangi potensi praktik korupsi, untuk pertemuan antara panitia lelang dan peserta lelang tidak terbatas. Pada saat pelelangan masih dipraktekkan secara luas dalam pertemuan langsung konvensional antara peserta lelang dan panitia lelang yang telah membuka peluang terjadinya "transaksi negatif". Dengan sistem e-procurement dokumen penawaran disampaikan dalam bentuk soft melalui internet dan hanya bisa dibuka sesuai jadwal. Faktor pembatas e-procurement dalam hal kegiatan perencanaan dan rencana anggaran PSU tidak termasuk oleh departemen perencanaan, munculnya rasa ketidakpuasan karyawan staf PSU karena tidak cocok dengan beban kerja yang diangkut oleh tambahan jumlah pendapatan yang diperoleh , ketidaktepatan dalam mentransfer karyawan staf PSU. Pelajaran yang dapat kita peroleh dari upaya ini bahwa ada komitmen yang kuat dari tingkat kepemimpinan puncak hingga tingkat staf mereka sebagai pelaksana dalam kegiatan nyata yang merupakan faktor penting dari kunci keberhasilan sistem implementasi e-procurement di Universitas Lampung.
Why we still don't need/want variables: Two SALTy case studies
Authors: Jacobson Pauline 
Published: January 2020

This paper defends the claim that variables and assignment functions are not needed as part of the semantic machinery against two apparent challenges. The relevant domains at first glance appear to show the need for variable names - but only if the variable-ful theory is supplemented with a stipulation preventing 'meaningless coindexation'. I argue that not only are both domains amenable to variable free analyses, but that indeed the variable free analyses have advnatages over the analyses using variables.
Spectroscopically Identified Cataclysmic Variables from the LAMOST Survey. I. The Sample
Authors: Hou Wen , Luo A-li , Li Yin-Bi , Qin Li 
Published: January 2020

Abstract
A sample of cataclysmic variables (CVs) is presented including spectroscopically identified 380 spectra of 245 objects, of which 58 CV candidates are new discoveries. The BaggingTopPush and the Random Forest algorithms are applied to the Fifth Data Release (DR5) of the Large Sky Area Multi-Object Fiber Spectroscopic Telescope (LAMOST) to retrieve CVs with strong emission lines and with broad absorption lines respectively. Based on spectroscopic classification, 134 dwarf novae, 41 nova-like variables, and 19 magnetic CVs are identified from the sample. In addition, 89 high-inclination systems and 33 CVs showing companion stars are recognized and discussed for their distinct spectral characteristics. Comparisons between CVs from LAMOST and from published catalogs are made in spatial and magnitude distribution, and the difference of their locus in the Gaia color–absolute magnitude diagram (CaMD) are also investigated. More interestingly, for two dwarf novae observed through LAMOST and SDSS in different epochs, their spectra both in quiescence phase and during outburst are exhibited.
Explosive Nucleosynthesis in Sub-Chandrasekhar-mass White Dwarf Models for Type Ia Supernovae: Dependence on Model Parameters
Authors: Leung Shing-Chi , Nomoto Ken’ichi 
Published: January 2020

Abstract
Recent observations of Type Ia supernovae (SNe Ia) have shown diversified properties of the explosion strength, light curves, and chemical composition. To investigate possible origins of such diversities in SNe Ia, we have presented multidimensional hydrodynamical studies of explosions and associated nucleosynthesis in near-Chandrasekhar-mass carbon–oxygen (CO) white dwarfs (WDs) for a wide range of parameters. In the present paper, we extend our wide parameter survey of models to the explosions of sub-Chandrasekhar-mass CO WDs. We take the double-detonation model for the explosion mechanism. The model parameters of the survey include a metallicity of Z = 0–5 Z
⊙, a CO WD mass of M = 0.90–1.20 M
⊙, and a He envelope mass of M
He = 0.05–0.20 M
⊙. We also study how the initial He detonation configuration, such as spherical, bubble, and ring shapes, triggers the C detonation. For these parameters, we derive the minimum He envelope mass necessary to trigger the C detonation. We then examine how the explosion dynamics and associated nucleosynthesis depend on these parameters, and we compare our results with the previous representative models. We compare our nucleosynthesis yields with the unusual abundance patterns of Fe-peak elements and isotopes observed in SNe Ia SN 2011fe, SN 2012cg, and SN 2014J, as well as SN Ia remnant 3C 397, to provide constraints on their progenitors and environments. We provide the nucleosynthesis yields table of the sub-Chandrasekhar-mass explosions, to discuss their roles in the galactic chemical evolution and archaeology.
L’État sourcier
Authors: Gomez-Temesio Veronica 
Published: January 2020

Depuis les années 1980, l’eau est devenue un objet de préoccupation au sein de la communauté internationale. Cette substance vitale a désormais acquis une valeur marchande qui dicte la conditionnalité de l'aide au développement dans les pays du Sud.
Le forage hydraulique est au cœur de la réforme de privatisation qui traverse le Sénégal. Pour appréhender cette infrastructure, l’auteur revisite une posture ethnographique popularisée par l’École de Manchester : l’entrée sur le terrain par les conflits. En mettant en lumière les différents dysfonctionnements que connaissent les forages, elle interroge les processus au travers desquels se négocient et se construisent autorité publique et légitimité politique dans le Sénégal contemporain.
Cette étude ethnographique minutieuse explore le processus de formation de l’État au carrefour de l’anthropologie politique, de l’anthropologie juridique et de l’anthropologie du développement. Le forage apparaît ici comme un lieu de l’État et pour l’État.
À ce dernier, le forage permet de se construire et de se reproduire sur son territoire. Aux sciences sociales, de répondre aux questions suivantes : comment penser l’État ? Comment fonctionne-t-il en Afrique ?
High-Tidal-Volume Mechanical Ventilation and Lung Inflammation in Intensive Care Patients With Normal Lungs
Authors: Ziaka Mairi , Makris Demosthenes , Fotakopoulos George , Tsilioni Irini , Befani Christina , Liakos Panagiotis , Zygoulis Paris , Zakynthinos Epaminondas 
Published: January 2020

Background
This study was conducted to investigate whether high-tidal-volume mechanical ventilation is associated with increased lung inflammation compared with low-tidal-volume mechanical ventilation in critically ill patients with no evidence of lung injury.

Methods
In this prospective, single-blind, randomized (1:1), parallel-group study, 18 critically ill patients with normal lungs were randomly assigned to receive mechanical ventilation with a tidal volume of either 6 mL/kg (low tidal volume) or 12 mL/kg (high tidal volume) during the first 4 days in the intensive care unit.

Results
At baseline and at 24, 48, and 96 hours, exhaled breath condensate was collected to measure interleukin 1β, interleukin 10, tumor necrosis factor α, and total nitric oxide metabolites. Interleukin 1β levels in exhaled breath condensate were significantly increased at 24 hours compared with baseline in the high-tidal-volume group but not in the low-tidal-volume group. The interleukin 1β increase in the high-tidal-volume group was transient. Exhaled breath condensate levels of interleukin 1β, interleukin 10, tumor necrosis factor α, and total nitric oxide metabolites did not differ significantly between the high-tidal-volume and low-tidal-volume groups at any time point.

Conclusion
Short-term mechanical ventilation with a tidal volume of 12 mL/kg may trigger inflammatory responses in the lungs of intensive care unit patients without preexisting lung injury.
Pneumothoraces Prevented With Use of Electromagnetic Device to Place Feeding Tubes
Authors: Bourgault Annette M. , Powers Jan , Aguirre Lillian 
Published: January 2020

Background
A US Food and Drug Administration safety letter warned about the risk for pneumothoraces during feeding tube insertion despite the use of electromagnetic placement devices that provide real-time visualization of feeding tube position.

Objectives
To systematically assess pulmonary placement and pneumothoraces in CORTRAK-assisted feeding tube insertions.

Methods
CINAHL, MEDLINE, and Cochrane databases were searched for studies of CORTRAK-assisted feeding tube insertion. Thirty-two studies documenting pulmonary placement and/or complications of feeding tube insertion were found.

Results
Operators recognized pulmonary placement on insertion tracings during 202 CORTRAK-assisted feeding tube insertion procedures, resulting in the immediate withdrawal of 199 feeding tubes. One pneumothorax was identified later by radiography. Seven pulmonary placements were not recognized by CORTRAK operators at the time of feeding tube insertion, resulting in 2 pneumothoraces. The incidence of pneumothorax for CORTRAK-assisted feeding tube insertions was 0.02% (3 of 17039). Of the feeding tubes inserted into the pulmonary system – either found during or after the procedure −1.4% (3 of 209) resulted in pneumothoraces (as opposed to the 19% to 28% incidence of pneumothorax for blind feeding tube insertions. Operators recognizing pulmonary placement on CORTRAK insertion tracings may have prevented 97% (202 of 209) of feeding tubes from being inserted farther into the respiratory tract.

Conclusions
Feeding tube insertion with an electromagnetic placement device is advantageous over blind feeding tube insertion because the operator can recognize pulmonary placement early and withdraw the feeding tube, thus decreasing the risk of pulmonary complications.
Nurse Prompting for Prescriber-Led Review of Antimicrobial Use in the Critical Care Unit
Authors: Raybardhan Sumit , Kan Tiffany , Chung Bonnie , Ferreira Danielle , Bitton Marina , Shin Phil , Das Pavani 
Published: January 2020

Background
Developing a sustainable strategy for prescriber-led review of antimicrobial use in a critical care unit may improve antimicrobial use without the need for additional resources.

Methods
Using a quality improvement framework, the researchers created a prompt for prescriber-led review of antimicrobial use. The outcome measure was antimicrobial use (days of therapy per 1000 patient days). The process measure was the proportion of relevant cases for which an antimicrobial prompt was provided. Balancing measures included mortality rate, length of stay, 48-hour readmission rates, and multiple organ dysfunction score. Interrupted time series with segmented regression analysis was used for the outcome measure.

Results
Process analysis identified critical care unit nurses for antimicrobial use prompting. A standard script was developed to incorporate a days of therapy prompt into nurse rounds, with primed prescriber responses. Before the intervention, monthly antimicrobial use was 804 days of therapy per 1000 patient days, with a positive trend (7.3 days of therapy per 1000 patient days, P &lt; .05). After the intervention, there was an immediate reduction of 217 days of therapy per 1000 patient days (P &lt; .05), with a nonsignificant negative trend, representing a 20% (95% CI, −15% to −25%) reduction. No significant change was noted in use of the control class of medications. The proportion of relevant cases for which an antimicrobial prompt was provided increased from 21% to 48% during the intervention period. Balancing measures were comparable before and after the intervention.

Conclusions
Nurse prompting can lead to significant reductions in antimicrobial use, providing a sustainable mechanism for independent antimicrobial reassessment.