bluuebunny/crossref_metadata_2025_split huggingface dataset:
Assessing Antimicrobial Resistance, Utilization, and Stewardship in Yemen: An Exploratory Mixed-Methods Study
Authors: Orubu Ebiowei S. F. , Al-Dheeb Najwa , Ching Carly , Bu Jawdeh Sima , Anderson Jessica , Sheikh Rashad , Hariri Fadhel , Basaleem Huda , Zaman Muhammad H. 
Published: August 2021

ABSTRACT.
Antimicrobial resistance (AMR), largely driven by irrational use of antimicrobials, is a global, multifaceted problem calling for a complete understanding of all contributory factors for effective containment. In conflict settings, war-wounds and malnutrition can combine with existing social determinants to increase demand for antibiotics, compounding irrational use. In this study, we focus on Yemen, a low-income country with active conflict for the last 5 years, and analyze the current status of awareness and stewardship efforts regarding AMR. We performed a survey of prescribers/physicians and pharmacists to describe perceptions of AMR prevalence, antibiotic use practices, and stewardship in Yemen, supported by a nonsystematic scoping literature review and a key informant interview. Participants (96%, N = 54) reported a perceived high AMR prevalence rate. Prescribers (74%, 20/27) reported pressure to prescribe broad-spectrum antibiotics. In the majority of cases (81%, 22/27), antimicrobial sensitivity tests (AST) were not performed to inform antibiotic choice. The main barrier to AST was cost. Most pharmacists (67%, 18/27) sold antibiotics without prescriptions. Amoxicillin (including amoxicillin-clavulanate) was the most-commonly prescribed (63%, 17/27) or dispensed (81%, 22/27) antibiotic. AST was rated the least important solution to AMR in Yemen. While there was awareness of a high AMR rate, stewardship is poor in Yemen. We note that barriers to the use of AST could be addressed through the deployment of reliable, affordable, quality rapid diagnostics, and AST kits. Compulsory continuing education emphasizing the use of AST to guide prescribing and patients’ awareness programs could help avoid irrational use.
Bazı Tane Sorgum ve Sorgum X Sudanotu Melezi Çeşitlerinde Ekim Zamanının Verim ve Verim Unsurlarına Etkisi Üzerine Bir Araştırma
Authors: Kemal YILDIRIM  , Gülşah BENGİSU  
Published: August 2021

Bu araştırma bazı tane sorgum ve sorgum sudanotu melezi çeşitlerinde ekim zamanının verim ve verim unsurlarına etkisi üzerine Toprak Mahsulleri Ofisi Viranşehir Ajans Müdürlüğü tesisleri uygulama arazisinde yürütülmüştür. Deneme bölünmüş parseller deneme desenine göre 3 tekerrürlü olarak oluşturulmuştur. Araştırmada ana parselleri çeşitler, Kws, Fito, Hay day ve Akdarı alt parselleri ise ekim zamanları 25 Haziran, 5 Temmuz ve 15 Temmuz olarak oluşturulmuştur. 3 farklı zamanda ekimi yapılan sorgumun bölünmüş parseller deneme desenine göre analizler yapılmıştır. Analizlerle: % 50 çiçeklenme gün sayısı, olgunlaşma gün sayısı, bitki boyu, yaprak sayısı, sap kalınlığı, salkım uzunluğu, salkım ağırlığı, salkım başına tane verimi, salkım başına tane sayısı, salkımda tane oranı, tane verimi, 1000 tane ağırlığı, hektolitre ağırlığı ve ham protein oranı sonuçları incelenmiştir. Bu araştırma sonucunda ele alınan özellikler irdelendiğinde Şanlıurfa ili Viranşehir ilçesi koşullarında sorgum bitkisinin tane verimi bakımından Akdarı ve Hay day çeşitlerinin ilk ekim zamanı, yeşil ot bakımından Fito ve Kws çeşitlerinin ilk ekim zamanı önerilmektedir.
Canonical forms for free κ-semigroups
Authors: Costa José Carlos 
Published: August 2021

Automata, Logic and Semantics
The implicit signature κ consists of the multiplication and the (ω-1)-power. We describe a procedure to transform each κ-term over a finite alphabet A into a certain canonical form and show that different canonical forms have different interpretations over some finite semigroup. The procedure of construction of the canonical forms, which is inspired in McCammond\textquoterights normal form algorithm for ω-terms interpreted over the pseudovariety A of all finite aperiodic semigroups, consists in applying elementary changes determined by an elementary set Σ of pseudoidentities. As an application, we deduce that the variety of κ-semigroups generated by the pseudovariety S of all finite semigroups is defined by the set Σ and that the free κ-semigroup generated by the alphabet A in that variety has decidable word problem. Furthermore, we show that each ω-term has a unique ω-term in canonical form with the same value over A. In particular, the canonical forms provide new, simpler, representatives for ω-terms interpreted over that pseudovariety.
An S-adic characterization of minimal subshifts with first difference of complexity 1 ≤ p(n+1) - p(n) ≤ 2
Authors: Leroy Julien 
Published: August 2021

Automata, Logic and Semantics
An S-adic characterization of minimal subshifts with first difference of complexity 1 ≤ p(n + 1) − p(n) ≤ 2 S. Ferenczi proved that any minimal subshift with first difference of complexity bounded by 2 is S-adic with Card(S) ≤ 3 27. In this paper, we improve this result by giving an S-adic characterization of these subshifts with a set S of 5 morphisms, solving by this way the S-adic conjecture for this particular case.
A combinatorial non-commutative Hopf algebra of graphs
Authors: Tanasa Adrian , Duchamp Gerard , Foissy Loïc , Hoang-Nghia Nguyen , Manchon Dominique 
Published: August 2021

Combinatorics
A non-commutative, planar, Hopf algebra of planar rooted trees was defined independently by one of the authors in Foissy (2002) and by R. Holtkamp in Holtkamp (2003). In this paper we propose such a non-commutative Hopf algebra for graphs. In order to define a non-commutative product we use a quantum field theoretical (QFT) idea, namely the one of introducing discrete scales on each edge of the graph (which, within the QFT framework, corresponds to energy scales of the associated propagators). Finally, we analyze the associated quadri-coalgebra and codendrifrom structures.
A Parameterized Measure-and-ConquerAnalysis for Finding a k-Leaf Spanning Treein an Undirected Graph
Authors: Binkele-Raible Daniel , Fernau Henning 
Published: August 2021

Discrete Algorithms
The problem of finding a spanning tree in an undirected graph with a maximum number of leaves is known to be NP-hard. We present an algorithm which finds a spanning tree with at least k leaves in time O*(3.4575k) which improves the currently best algorithm. The estimation of the running time is done by using a non-standard measure. The present paper is one of the still few examples that employ the Measure & Conquer paradigm of algorithm analysis in the area of Parameterized Algorithmics.
The generalized 3-connectivity of Lexicographic product graphs
Authors: Li Xueliang , Mao Yaping 
Published: August 2021

Graph Theory
The generalized k-connectivity κk(G) of a graph G, first introduced by Hager, is a natural generalization of the concept of (vertex-)connectivity. Denote by G^H and G&Box;H the lexicographic product and Cartesian product of two graphs G and H, respectively. In this paper, we prove that for any two connected graphs G and H, κ3(G^H)&#x2265; κ3(G)|V(H)|. We also give upper bounds for κ3(G&Box; H) and κ3(G^H). Moreover, all the bounds are sharp.
Stokes posets and serpent nests
Authors: Chapoton Frédéric 
Published: August 2021

30 pages, 12 figures
We study two different objects attached to an arbitrary quadrangulation of a regular polygon. The first one is a poset, closely related to the Stokes polytopes introduced by Baryshnikov. The second one is a set of some paths configurations inside the quadrangulation, satisfying some specific constraints. These objects provide a generalisation of the existing combinatorics of cluster algebras and nonnesting partitions of type A.
On étudie deux objets attachés à une quadrangulation quelconque d'un polygone régulier. Le premier objet est un ensemble partiellement ordonné, fortement lié aux polytopes de Stokes introduits par Barysknikov. Le second est un ensemble de configurations de chemins dans la quadrangulation. Ces deux objets généralisent respectivement les aspects combinatoires des algèbres amassées et des partitions non-emboitées de type A.
Coloring and Guarding Arrangements
Authors: Bose Prosenjit , Cardinal Jean , Collette Sébastien , Hurtado Ferran , Korman Matias , Langerman Stefan , Taslakian Perouz 
Published: August 2021

Combinatorics
Given an arrangement of lines in the plane, what is the minimum number c of colors required to color the lines so that no cell of the arrangement is monochromatic? In this paper we give bounds on the number c both for the above question, as well as some of its variations. We redefine these problems as geometric hypergraph coloring problems. If we define $\Hlinecell$ as the hypergraph where vertices are lines and edges represent cells of the arrangement, the answer to the above question is equal to the chromatic number of this hypergraph. We prove that this chromatic number is between Ω(logn/loglogn). and O(n√). Similarly, we give bounds on the minimum size of a subset S of the intersections of the lines in A such that every cell is bounded by at least one of the vertices in S. This may be seen as a problem on guarding cells with vertices when the lines act as obstacles. The problem can also be defined as the minimum vertex cover problem in the hypergraph $\Hvertexcell$, the vertices of which are the line intersections, and the hyperedges are vertices of a cell. Analogously, we consider the problem of touching the lines with a minimum subset of the cells of the arrangement, which we identify as the minimum vertex cover problem in the $\Hcellzone$ hypergraph.
On additive combinatorics of permutations of ℤ<sub>n</sub>
Authors: Chandran L. Sunil , Rajendraprasad Deepak , Singh Nitin 
Published: August 2021

Special issue PRIMA 2013
Let ℤ<sub>n</sub> denote the ring of integers modulo n. A permutation of ℤ<sub>n</sub> is a sequence of n distinct elements of ℤ<sub>n</sub>. Addition and subtraction of two permutations is defined element-wise. In this paper we consider two extremal problems on permutations of ℤ<sub>n</sub>, namely, the maximum size of a collection of permutations such that the sum of any two distinct permutations in the collection is again a permutation, and the maximum size of a collection of permutations such that no sum of two distinct permutations in the collection is a permutation. Let the sizes be denoted by s(n) and t(n) respectively. The case when n is even is trivial in both the cases, with s(n)=1 and t(n)=n!. For n odd, we prove (nφ(n))/2<sup>k</sup>≤s(n)≤n!· 2<sup>-(n-1)/2</sup>((n-1)/2)! and 2<sup>(n-1)/2</sup>·(n-1 / 2)!≤t(n)≤ 2<sup>k</sup>·(n-1)!/φ(n), where k is the number of distinct prime divisors of n and φ is the Euler's totient function.
A matroid associated with a phylogenetic tree
Authors: Dress Andreas , Huber Katharina , Steel Mike 
Published: August 2021

Special issue PRIMA 2013
A (pseudo-)metric D on a finite set X is said to be a \textquotelefttree metric\textquoteright if there is a finite tree with leaf set X and non-negative edge weights so that, for all x,y ∈X, D(x,y) is the path distance in the tree between x and y. It is well known that not every metric is a tree metric. However, when some such tree exists, one can always find one whose interior edges have strictly positive edge weights and that has no vertices of degree 2, any such tree is &#x2013; up to canonical isomorphism &#x2013; uniquely determined by D, and one does not even need all of the distances in order to fully (re-)construct the tree\textquoterights edge weights in this case. Thus, it seems of some interest to investigate which subsets of X, 2 suffice to determine (\textquoteleftlasso\textquoteright) these edge weights. In this paper, we use the results of a previous paper to discuss the structure of a matroid that can be associated with an (unweighted) X-tree T defined by the requirement that its bases are exactly the \textquotelefttight edge-weight lassos\textquoteright for T, i.e, the minimal subsets of X, 2 that lasso the edge weights of T.
Hamiltonian decomposition of prisms over cubic graphs
Authors: Rosenfeld Moshe , Xiang Ziqing 
Published: August 2021

Special issue PRIMA 2013
The prisms over cubic graphs are 4-regular graphs. The prisms over 3-connected cubic graphs are Hamiltonian. In 1986 Brian Alspach and Moshe Rosenfeld conjectured that these prisms are Hamiltonian decomposable. In this paper we present a short survey of the status of this conjecture, various constructions proving that certain families of prisms over 3-connected cubic graphs are Hamiltonian decomposable. Among others, we prove that the prisms over cubic Halin graphs, cubic generalized Halin graphs of order 4k + 2 and other infinite sequences of cubic graphs are Hamiltonian decomposable.
Determining pure discrete spectrum for some self-affine tilings
Authors: Akiyama Shigeki , Gähler Franz , Lee Jeong-Yup 
Published: August 2021

Discrete Algorithms
By the algorithm implemented in the paper by Akiyama-Lee [Adv. Math. 226(4):2855 13;2883, 2011] and some of its predecessors, we have examined the pure discreteness of the spectrum for all irreducible Pisot substitutions of trace less than or equal to 2, and some cases of planar tilings generated by boundary substitutions due to Kenyon [Geom. Func. Anal. 6:471 13;488, 1996].
Oriented diameter and rainbow connection number of a graph
Authors: Huang Xiaolong , Li Hengzhe , Li Xueliang , Sun Yuefang 
Published: August 2021

Graph Theory
The oriented diameter of a bridgeless graph G is min diam(H) | H is a strang orientation of G. A path in an edge-colored graph G, where adjacent edges may have the same color, is called rainbow if no two edges of the path are colored the same. The rainbow connection number rc(G) of G is the smallest integer number k for which there exists a k-edge-coloring of G such that every two distinct vertices of G are connected by a rainbow path. In this paper, we obtain upper bounds for the oriented diameter and the rainbow connection number of a graph in terms of rad(G) and η(G), where rad(G) is the radius of G and η(G) is the smallest integer number such that every edge of G is contained in a cycle of length at most η(G). We also obtain constant bounds of the oriented diameter and the rainbow connection number for a (bipartite) graph G in terms of the minimum degree of G.
Maximum difference about the size of optimal identifying codes in graphs differing by one vertex
Authors: Pelto Mikko 
Published: August 2021

Graph Theory
Let G=(V,E) be a simple undirected graph. We call any subset C⊆V an identifying code if the sets I(v)={c∈C | {v,c}∈E or v=c } are distinct and non-empty for all vertices v∈V. A graph is called twin-free if there is an identifying code in the graph. The identifying code with minimum size in a twin-free graph G is called the optimal identifying code and the size of such a code is denoted by γ(G). Let GS denote the induced subgraph of G where the vertex set S⊂V is deleted. We provide a tight upper bound for γ(GS)-γ(G) when both graphs are twin-free and |V| is large enough with respect to |S|. Moreover, we prove tight upper bound when G is a bipartite graph and |S|=1.
How often should you clean your room?
Authors: Martin Kimball , Shankar Krishnan 
Published: August 2021

Analysis of Algorithms
We introduce and study a combinatorial optimization problem motivated by the question in the title. In the simple case where you use all objects in your room equally often, we investigate asymptotics of the optimal time to clean up in terms of the number of objects in your room. In particular, we prove a logarithmic upper bound, solve an approximate version of this problem, and conjecture a precise logarithmic asymptotic.
Connectivity of Fibonacci cubes, Lucas cubes and generalized cubes
Authors: Azarija Jernej , Klavžar Sandi , Lee Jaehun , Rho Yoomi 
Published: August 2021

Graph Theory
If f is a binary word and d a positive integer, then the generalized Fibonacci cube Qd(f) is the graph obtained from the d-cube Qd by removing all the vertices that contain f as a factor, while the generalized Lucas cube Qd(lucas(f)) is the graph obtained from Qd by removing all the vertices that have a circulation containing f as a factor. The Fibonacci cube Γd and the Lucas cube Λd are the graphs Qd(11) and Qd(lucas(11)), respectively. It is proved that the connectivity and the edge-connectivity of Γd as well as of Λd are equal to ⌊ d+2 / 3⌋. Connected generalized Lucas cubes are characterized and generalized Fibonacci cubes are proved to be 2-connected. It is asked whether the connectivity equals minimum degree also for all generalized Fibonacci/Lucas cubes. It was checked by computer that the answer is positive for all f and all d≤9.
On the 1-2-3-conjecture
Authors: Davoodi Akbar , Omoomi Behnaz 
Published: August 2021

Graph Theory
A k-edge-weighting of a graph G is a function w:E(G)→{1,…,k}. An edge-weighting naturally induces a vertex coloring c, where for every vertex v∈V(G), c(v)=∑e∼vw(e). If the induced coloring c is a proper vertex coloring, then w is called a vertex-coloring k-edge-weighting (VC k-EW). Karoński et al. (J. Combin. Theory Ser. B, 91 (2004) 151 13;157) conjectured that every graph admits a VC 3-EW. This conjecture is known as the 1-2-3-conjecture. In this paper, first, we study the vertex-coloring edge-weighting of the Cartesian product of graphs. We prove that if the 1-2-3-conjecture holds for two graphs G and H, then it also holds for G□H. Also we prove that the Cartesian product of connected bipartite graphs admits a VC 2-EW. Moreover, we present several sufficient conditions for a graph to admit a VC 2-EW. Finally, we explore some bipartite graphs which do not admit a VC 2-EW.
Edge stability in secure graph domination
Authors: Burger Anton Pierre , Villiers Alewyn Petrus , Vuuren Jan Harm 
Published: August 2021

Graph Theory
A subset X of the vertex set of a graph G is a secure dominating set of G if X is a dominating set of G and if, for each vertex u not in X, there is a neighbouring vertex v of u in X such that the swap set (X-v)∪u is again a dominating set of G. The secure domination number of G is the cardinality of a smallest secure dominating set of G. A graph G is p-stable if the largest arbitrary subset of edges whose removal from G does not increase the secure domination number of the resulting graph, has cardinality p. In this paper we study the problem of computing p-stable graphs for all admissible values of p and determine the exact values of p for which members of various infinite classes of graphs are p-stable. We also consider the problem of determining analytically the largest value ωn of p for which a graph of order n can be p-stable. We conjecture that ωn=n-2 and motivate this conjecture.
On probe 2-clique graphs and probe diamond-free graphs
Authors: Bonomo Flavia , Figueiredo Celina M. H. , Duran Guillermo , Grippo Luciano N. , Safe Martín D. , Szwarcfiter Jayme L. 
Published: August 2021

Graph Theory
Given a class G of graphs, probe G graphs are defined as follows. A graph G is probe G if there exists a partition of its vertices into a set of probe vertices and a stable set of nonprobe vertices in such a way that non-edges of G, whose endpoints are nonprobe vertices, can be added so that the resulting graph belongs to G. We investigate probe 2-clique graphs and probe diamond-free graphs. For probe 2-clique graphs, we present a polynomial-time recognition algorithm. Probe diamond-free graphs are characterized by minimal forbidden induced subgraphs. As a by-product, it is proved that the class of probe block graphs is the intersection between the classes of chordal graphs and probe diamond-free graphs.
Guarded subgraphs and the domination game
Authors: Brešar Boštjan , Klavžar Sandi , Košmrlj Gasper , Rall Doug F. 
Published: August 2021

Graph Theory
We introduce the concept of guarded subgraph of a graph, which as a condition lies between convex and 2-isometric subgraphs and is not comparable to isometric subgraphs. Some basic metric properties of guarded subgraphs are obtained, and then this concept is applied to the domination game. In this game two players, Dominator and Staller, alternate choosing vertices of a graph, one at a time, such that each chosen vertex enlarges the set of vertices dominated so far. The aim of Dominator is that the graph is dominated in as few steps as possible, while the aim of Staller is just the opposite. The game domination number is the number of vertices chosen when Dominator starts the game and both players play optimally. The main result of this paper is that the game domination number of a graph is not smaller than the game domination number of any guarded subgraph. Several applications of this result are presented.
Ore-degree threshold for the square of a Hamiltonian cycle
Authors: DeBiasio Louis , Faizullah Safi , Khan Imdadullah 
Published: August 2021

Graph Theory
A classic theorem of Dirac from 1952 states that every graph with minimum degree at least n=2 contains a Hamiltonian cycle. In 1963, P´osa conjectured that every graph with minimum degree at least 2n=3 contains the square of a Hamiltonian cycle. In 1960, Ore relaxed the degree condition in the Dirac’s theorem by proving that every graph with deg(u) + deg(v) ≥ n for every uv =2 E(G) contains a Hamiltonian cycle. Recently, Chˆau proved an Ore-type version of P´osa’s conjecture for graphs on n ≥ n0 vertices using the regularity–blow-up method; consequently the n0 is very large (involving a tower function). Here we present another proof that avoids the use of the regularity lemma. Aside from the fact that our proof holds for much smaller n0, we believe that our method of proof will be of independent interest.
Poset vectors and generalized permutohedra
Authors: Croitoru Dorian , Oh Suho , Postnikov Alexander 
Published: August 2021

We show that given a poset $P$ and and a subposet $Q$, the integer points obtained by restricting linear extensions of $P$ to $Q$ can be explained via integer lattice points of a generalized permutohedron.
Nous montrons que, étant donné un poset $P$ et un subposet $Q$, les points entiers obtenus en restreignant les extensions linéaires de $P$ à $Q$peuvent être expliqués par les points entiers d’un permutohedron généralisé.
On the Topology of the Cambrian Semilattices
Authors: Kallipoliti Myrto , Mühle Henri 
Published: August 2021

For an arbitrary Coxeter group $W$, David Speyer and Nathan Reading defined Cambrian semilattices $C_{\gamma}$ as certain sub-semilattices of the weak order on $W$. In this article, we define an edge-labelling using the realization of Cambrian semilattices in terms of $\gamma$-sortable elements, and show that this is an EL-labelling for every closed interval of $C_{\gamma}$. In addition, we use our labelling to show that every finite open interval in a Cambrian semilattice is either contractible or spherical, and we characterize the spherical intervals, generalizing a result by Nathan Reading.
Pour tout groupe de Coxeter $W$, David Speyer et Nathan Reading ont défini les demi-treillis Cambriens comme certains sous-demi-treillis de l’ordre faible sur $W$. Dans cet article, nous définissons un étiquetage des arêtes basé sur la réalisation des demi-treillis Cambriens en termes d’éléments$\gamma$-triables, et prouvons que c’est un étiquetage EL pour tout intervalle fermé de $C_{\gamma}$. Nous utilisons de plus cet étiquetage pour ontrer que tout intervalle ouvert fini dans un demi-treillis Cambrien est soit contractile soit sphérique, et nous caractérisons les intervalles sphériques,généralisant ainsi un résultat de Nathan Reading.
Redfield-Pólya theorem in $\mathrm{WSym}$
Authors: Bultel Jean-Paul , Chouria Ali , Luque Jean-Gabriel , Mallet Olivier 
Published: August 2021

We give noncommutative versions of the Redfield-Pólya theorem in $\mathrm{WSym}$, the algebra of word symmetric functions, and in other related combinatorial Hopf algebras.
Nous donnons des versions non-commutatives du théorème d’énumération de Redfield-Pólya dans $\mathrm{WSym}$, l’algèbre des fonctions symétriques sur les mots, ainsi que dans d’autres algèbres de Hopf combinatoires.