Parameterized complexity of the MINCCA problem on graphs of bounded decomposability

In an edge-colored graph, the cost incurred at a vertex on a path when two incident edges with different colors are traversed is called reload or changeover cost. The "Minimum Changeover Cost Arborescence" (MINCCA) problem consists in finding an arborescence with a given root vertex such that the total changeover cost of the internal vertices is minimized. It has been recently proved by G\"oz\"upek et al. [TCS 2016] that the problem is FPT when parameterized by the treewidth and the maximum degree of the input graph. In this article we present the following results for the MINCCA problem: - the problem is W[1]-hard parameterized by the treedepth of the input graph, even on graphs of average degree at most 8. In particular, it is W[1]-hard parameterized by the treewidth of the input graph, which answers the main open problem of G\"oz\"upek et al. [TCS 2016]; - it is W[1]-hard on multigraphs parameterized by the tree-cutwidth of the input multigraph; - it is FPT parameterized by the star tree-cutwidth of the input graph, which is a slightly restricted version of tree-cutwidth. This result strictly generalizes the FPT result given in G\"oz\"upek et al. [TCS 2016]; - it remains NP-hard on planar graphs even when restricted to instances with at most 6 colors and 0/1 symmetric costs, or when restricted to instances with at most 8 colors, maximum degree bounded by 4, and 0/1 symmetric costs.Comment: 25 pages, 11 figure

Phosphoric Acid Invasion in High Temperature PEM Fuel Cell Gas Diffusion Layers

In this work, liquid phosphoric acid was injected into polymer electrolyte membrane fuel cell (PEMFC) gas diffusion layers (GDLs) to visualize the invasion patterns developed at breakthrough. Three-dimensional (3D) images of the GDLs were obtained through X-ray computed tomography, and equivalent pore networks were generated as the basis for pore network simulations using OpenPNM. Strong qualitative agreement was obtained between the simulated and experimentally observed liquid phosphoric acid invasion patterns, which provided validation for the numerical modeling. Different GDL materials were evaluated by examining the effects of a micro porous layer (MPL) and pore size distribution on the saturation and distribution of phosphoric acid. The MPL was shown to restrict liquid phosphoric acid from entering the carbon fiber substrate. The overall phosphoric acid saturation at breakthrough was found to decrease significantly for samples containing an MPL due to the smaller pore sizes. Further, the influence of cracks in an MPL on overall saturation at breakthrough was investigated. It was observed that a crack-free MPL provided a more effective physical barrier to restrict the undesired leaching of liquid phosphoric acid through the GDL

Quantum Circuits for the Unitary Permutation Problem

We consider the Unitary Permutation problem which consists, given $n$ unitary gates $U_1, \ldots, U_n$ and a permutation $\sigma$ of $\{1,\ldots, n\}$, in applying the unitary gates in the order specified by $\sigma$, i.e. in performing $U_{\sigma(n)}\ldots U_{\sigma(1)}$. This problem has been introduced and investigated by Colnaghi et al. where two models of computations are considered. This first is the (standard) model of query complexity: the complexity measure is the number of calls to any of the unitary gates $U_i$ in a quantum circuit which solves the problem. The second model provides quantum switches and treats unitary transformations as inputs of second order. In that case the complexity measure is the number of quantum switches. In their paper, Colnaghi et al. have shown that the problem can be solved within $n^2$ calls in the query model and $\frac{n(n-1)}2$ quantum switches in the new model. We refine these results by proving that $n\log_2(n) +\Theta(n)$ quantum switches are necessary and sufficient to solve this problem, whereas $n^2-2n+4$ calls are sufficient to solve this problem in the standard quantum circuit model. We prove, with an additional assumption on the family of gates used in the circuits, that $n^2-o(n^{7/4+\epsilon})$ queries are required, for any $\epsilon >0$. The upper and lower bounds for the standard quantum circuit model are established by pointing out connections with the permutation as substring problem introduced by Karp.Comment: 8 pages, 5 figure

Preventive hygiene protocol of University of Milan for women during pregnancy: A qualitative and quantitative bacterial plaque analysis prospective original study

Introduction: The aim of this article is to describe the preventive hygiene protocol of University of Milan for women during pregnancy analyzing the bacterial plaque quantitatively and qualitatively. Materials and methods: A sample of 35 pregnant women following a protocol of periodic visits starting from the first month of pregnancy until the childbirth and in follow up controls were analyzed. Several samples (n = 4) of bacterial plaque for quantitative and qualitative analysis were taken, from the lingual surface of the lower first molar, during the first visit (T0), during the first trimester (T1), during the second or third trimester of pregnancy (T2), and one month after childbirth (T3). Results: By performing a quantitative analysis, it was calculated that the average plaque index (Fig. 1) was n = 48.1% (T0), n = 14.7% (T1), n = 18.4% (T2) and n = 18.9% (T3). The plaque index score presents a downward trend, passing from 48.1% (T0) to 18.9% (T3). The number of total cocci (Fig. 2) was n = 205.39 (T0), n = 57.5(T1), n = 74.6 (T2) and n = 75.4(T3). The number of total bacilli (Fig. 3) was n = 62.7 (T0), n = 23.1 (T1), n = 25.3 (T2), n = 27.1(T3). The total values of cocci and bacilli were correlated and the average trend of the various samples was calculated. By performing a qualitative analysis, the value of G+ cocci (Fig. 5) was n = 2.7 (T0), n = 1.4 (T1), n = 1.4 (T2) and n = 1.5 (T3). The value of G 12 cocci (Fig. 5) was n = 2.3 (T0), n = 0.7 (T1), n = 1.1 (T2) and n = 1.1 (T3). The value of G+ bacilli (Fig. 6) was n = 1.6 (T0), n = 0.9 (T1), n = 1.2 (T2) and n = 1.2 (T3). The value of G 12 bacilli (Fig. 6) was n = 1.3 (T0), n = 0.3 (T1), n = 0.7 (T2) and n = 0.7 (T3). Conclusions: The preventive hygiene protocol used in the Dental Hygiene Department of the University of Milan, during the gestation period, is a suitable method for the control of the bacterial plaque. A considerably decrease of the plaque index and bacterial components between the first visit and the subsequent check-ups was calculated

The future of stem cells in liver diseases.

Preliminary experience with clinical hepatocyte transplantation during the past decade has provided proof of concept that cell therapy can be effective for the treatment of some liver diseases. Recent progress in cell biology resulting in the isolation and characterization of hepatic stem cells and progenitor cells further increased the expectation for a new approach to the treatment of genetic and chronic liver disease. Several potential sources have been identified of hepatic stem/ progenitor cells exhibiting both differentiation towards the hepatic lineage in vitro and hepatic parenchymal repopulation with liver-specific metabolic activity in liver-injured animal models. However, a few of these results proved to be poorly reproducible in different laboratories, and it was recognized that some initial optimistic conclusions were drawn from incorrect interpretation of experimental data or from insufficient knowledge of the mechanisms involved in tissue regeneration. Moreover, only modest results have emerged so far from ongoing clinical experience involving the use of putative stem cells in liver disease. There is much need for a joined effort to concentrate the resources on a specific cell population, in order to better characterize its function, to assess its safety and Concise Revie

Dual-domain reporter approach for multiplex identification of major SARS-CoV-2 variants of concern in a microarray-based assay

: Since the emergence of the COVID-19 pandemic in December 2019, the SARS-CoV-2 virus continues to evolve into many variants emerging around the world. To enable regular surveillance and timely adjustments in public health interventions, it is of the utmost importance to accurately monitor and track the distribution of variants as rapidly as possible. Genome sequencing is the gold standard for monitoring the evolution of the virus, but it is not cost-effective, rapid and easily accessible. We have developed a microarray-based assay that can distinguish known viral variants present in clinical samples by simultaneously detecting mutations in the Spike protein gene. In this method, the viral nucleic acid, extracted from nasopharyngeal swabs, after RT-PCR, hybridizes in solution with specific dual-domain oligonucleotide reporters. The domains complementary to the Spike protein gene sequence encompassing the mutation form hybrids in solution that are directed by the second domain ("barcode" domain) at specific locations on coated silicon chips. The method utilizes characteristic fluorescence signatures to unequivocally differentiate, in a single assay, different known SARS-CoV-2 variants. In the nasopharyngeal swabs of patients, this multiplex system was able to genotype the variants which have caused waves of infections worldwide, reported by the WHO as being of concern (VOCs), namely Alpha, Beta, Gamma, Delta and Omicron variants

The Parameterized Complexity of Domination-type Problems and Application to Linear Codes

We study the parameterized complexity of domination-type problems. (sigma,rho)-domination is a general and unifying framework introduced by Telle: a set D of vertices of a graph G is (sigma,rho)-dominating if for any v in D, |N(v)\cap D| in sigma and for any $v\notin D, |N(v)\cap D| in rho. We mainly show that for any sigma and rho the problem of (sigma,rho)-domination is W[2] when parameterized by the size of the dominating set. This general statement is optimal in the sense that several particular instances of (sigma,rho)-domination are W[2]-complete (e.g. Dominating Set). We also prove that (sigma,rho)-domination is W[2] for the dual parameterization, i.e. when parameterized by the size of the dominated set. We extend this result to a class of domination-type problems which do not fall into the (sigma,rho)-domination framework, including Connected Dominating Set. We also consider problems of coding theory which are related to domination-type problems with parity constraints. In particular, we prove that the problem of the minimal distance of a linear code over Fq is W[2] for both standard and dual parameterizations, and W[1]-hard for the dual parameterization. To prove W[2]-membership of the domination-type problems we extend the Turing-way to parameterized complexity by introducing a new kind of non deterministic Turing machine with the ability to perform `blind' transitions, i.e. transitions which do not depend on the content of the tapes. We prove that the corresponding problem Short Blind Multi-Tape Non-Deterministic Turing Machine is W[2]-complete. We believe that this new machine can be used to prove W[2]-membership of other problems, not necessarily related to dominationComment: 19 pages, 2 figure

Planning the Future of U.S. Particle Physics (Snowmass 2013): Chapter 4: Cosmic Frontier

These reports present the results of the 2013 Community Summer Study of the APS Division of Particles and Fields ("Snowmass 2013") on the future program of particle physics in the U.S. Chapter 4, on the Cosmic Frontier, discusses the program of research relevant to cosmology and the early universe. This area includes the study of dark matter and the search for its particle nature, the study of dark energy and inflation, and cosmic probes of fundamental symmetries.Comment: 61 page