2,726 research outputs found

    Semi- and fully synthetic carbohydrate vaccines against pathogenic bacteria : recent developments

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    The importance of vaccine-induced protection was repeatedly demonstrated over the last three decades and emphasized during the recent COVID-19 pandemic as the safest and most effective way of preventing infectious diseases. Vaccines have controlled, and in some cases, eradicated global viral and bacterial infections with high efficiency and at a relatively low cost. Carbohydrates form the capsular sugar coat that surrounds the outer surface of human pathogenic bacteria. Specific surface-exposed bacterial carbohydrates serve as potent vaccine targets that broadened our toolbox against bacterial infections. Since first approved for commercial use, antibacterial carbohydrate-based vaccines mostly rely on inherently complex and heterogenous naturally derived polysaccharides, challenging to obtain in a pure, safe, and cost-effective manner. The introduction of synthetic fragments identical with bacterial capsular polysaccharides provided well-defined and homogenous structures that resolved many challenges of purified polysaccharides. The success of semisynthetic glycoconjugate vaccines against bacterial infections, now in different phases of clinical trials, opened up new possibilities and encouraged further development towards fully synthetic antibacterial vaccine solutions. In this mini-review, we describe the recent achievements in semi- and fully synthetic carbohydrate vaccines against a range of human pathogenic bacteria, focusing on preclinical and clinical studies

    Reflections on a coaching pilot project in healthcare settings

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    This paper draws on personal reflection of coaching experiences and learning as a coach to consider the relevance of these approaches in a management context with a group of four healthcare staff who participated in a pilot coaching project. It explores their understanding of coaching techniques applied in management settings via their reflections on using coaching approaches and coaching applications as healthcare managers. Coaching approaches can enhance a manager’s skill portfolio and offer the potential benefits in terms of successful goal achievement, growth, mutual learning and development for both themselves and staff they work with in task focused scenarios

    Counting dependent and independent strings

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    The paper gives estimations for the sizes of the the following sets: (1) the set of strings that have a given dependency with a fixed string, (2) the set of strings that are pairwise \alpha independent, (3) the set of strings that are mutually \alpha independent. The relevant definitions are as follows: C(x) is the Kolmogorov complexity of the string x. A string y has \alpha -dependency with a string x if C(y) - C(y|x) \geq \alpha. A set of strings {x_1, \ldots, x_t} is pairwise \alpha-independent if for all i different from j, C(x_i) - C(x_i | x_j) \leq \alpha. A tuple of strings (x_1, \ldots, x_t) is mutually \alpha-independent if C(x_{\pi(1)} \ldots x_{\pi(t)}) \geq C(x_1) + \ldots + C(x_t) - \alpha, for every permutation \pi of [t]

    Degree spectra for transcendence in fields

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    We show that for both the unary relation of transcendence and the finitary relation of algebraic independence on a field, the degree spectra of these relations may consist of any single computably enumerable Turing degree, or of those c.e. degrees above an arbitrary fixed Δ20\Delta^0_2 degree. In other cases, these spectra may be characterized by the ability to enumerate an arbitrary Σ20\Sigma^0_2 set. This is the first proof that a computable field can fail to have a computable copy with a computable transcendence basis

    Mapping the MIS Curriculum Based on Critical Skills of New Graduates: An Empirical Examination of IT Professionals

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    MIS curricula research almost always focuses on either curriculum issues or the critical skills required of new MIS graduates, rarely both. This study examines both by determining the critical skills required of new graduates, from the perspective of IT professionals in the field, then uniquely mapping those skills into a comprehensive yet flexible MIS curriculum that could be used by any MIS department. Using a sample of 153 IT professionals from six organizations in the mid-South, the results are somewhat surprising. While personal attributes are important, IT workers clearly believe that technology skills are a critical component of an MIS education, in particular database skills (including SQL), computer languages (at least two), and web design proficiency. Results also stress the importance of foundational concepts and knowledge, preparing new graduates for careers and not merely their first job. The impact for MIS curriculum designers is clear: make the major technically robust while simultaneously providing a core foundation in both business and IT. The study strongly suggests that concentrations (two or more sequenced courses) are a must; four are recommended as a result of this study: programming/architecture, telecommunications/networks, database, and web design/e-commerce. Implications are discussed

    Tree Compression with Top Trees Revisited

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    We revisit tree compression with top trees (Bille et al, ICALP'13) and present several improvements to the compressor and its analysis. By significantly reducing the amount of information stored and guiding the compression step using a RePair-inspired heuristic, we obtain a fast compressor achieving good compression ratios, addressing an open problem posed by Bille et al. We show how, with relatively small overhead, the compressed file can be converted into an in-memory representation that supports basic navigation operations in worst-case logarithmic time without decompression. We also show a much improved worst-case bound on the size of the output of top-tree compression (answering an open question posed in a talk on this algorithm by Weimann in 2012).Comment: SEA 201

    On the complexity of computing the kk-restricted edge-connectivity of a graph

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    The \emph{kk-restricted edge-connectivity} of a graph GG, denoted by λk(G)\lambda_k(G), is defined as the minimum size of an edge set whose removal leaves exactly two connected components each containing at least kk vertices. This graph invariant, which can be seen as a generalization of a minimum edge-cut, has been extensively studied from a combinatorial point of view. However, very little is known about the complexity of computing λk(G)\lambda_k(G). Very recently, in the parameterized complexity community the notion of \emph{good edge separation} of a graph has been defined, which happens to be essentially the same as the kk-restricted edge-connectivity. Motivated by the relevance of this invariant from both combinatorial and algorithmic points of view, in this article we initiate a systematic study of its computational complexity, with special emphasis on its parameterized complexity for several choices of the parameters. We provide a number of NP-hardness and W[1]-hardness results, as well as FPT-algorithms.Comment: 16 pages, 4 figure

    Reconfiguration of Dominating Sets

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    We explore a reconfiguration version of the dominating set problem, where a dominating set in a graph GG is a set SS of vertices such that each vertex is either in SS or has a neighbour in SS. In a reconfiguration problem, the goal is to determine whether there exists a sequence of feasible solutions connecting given feasible solutions ss and tt such that each pair of consecutive solutions is adjacent according to a specified adjacency relation. Two dominating sets are adjacent if one can be formed from the other by the addition or deletion of a single vertex. For various values of kk, we consider properties of Dk(G)D_k(G), the graph consisting of a vertex for each dominating set of size at most kk and edges specified by the adjacency relation. Addressing an open question posed by Haas and Seyffarth, we demonstrate that DΓ(G)+1(G)D_{\Gamma(G)+1}(G) is not necessarily connected, for Γ(G)\Gamma(G) the maximum cardinality of a minimal dominating set in GG. The result holds even when graphs are constrained to be planar, of bounded tree-width, or bb-partite for b3b \ge 3. Moreover, we construct an infinite family of graphs such that Dγ(G)+1(G)D_{\gamma(G)+1}(G) has exponential diameter, for γ(G)\gamma(G) the minimum size of a dominating set. On the positive side, we show that Dnm(G)D_{n-m}(G) is connected and of linear diameter for any graph GG on nn vertices having at least m+1m+1 independent edges.Comment: 12 pages, 4 figure
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