1,425 research outputs found
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
VvMYB60 expression is restricted to guard cells and correlates with stomatal conductance in the grape leaf
Grapevine (Vitis vinifera L.) is traditionally grown under non-irrigated field conditions in many cropping environments, including dry lands and semiarid regions. Good osmotic adjustment, architecture of the root system, xylem embolism and efficient stomatal control of water loss account for the drought resistance traits of the Vitis genus. Among these features, the regulation of stomatal activity is of particular relevance, as it directly shapes the isohydric versus anysohydric behaviour of different grape species and cultivars. Increasing evidence indicates a role for the transcriptional control of gene expression in modulating stomatal responses to both biotic and abiotic stimuli. R2R3 MYB transcription factors have been identified as key regulators of stomatal opening and transpirational water loss under stress in different plant species. We identified the grape gene VvMYB60 (VIT_08s0056g00800) as the functional ortholog of AtMYB60 (At1g08810), involved in the regulation of stomatal activity in Arabidopsis. Here, we report results from the analysis of VvMYB60 expression in the grape leaf, including: 1. The qPCR analyses of stomata-enriched grape epidermal fragments and lasermicrodissected guard cells; 2. The confocal analysis of grape leaves agro-infiltrated with the VvMYB60promoter::GFP construct; 3. The analysis of changes in VvMYB60 expression relatively to variations in stomatal conductance (gs) in plants grown under control or drought stress conditions. As a whole our data confirmed the guard cell-specificity of VvMYB60 expression in the grape leaf and revealed a positive correlation between gs and the relative abundance of the VvMYB60 transcripts, thus substantiating the notion of VvMYB60 being a transcriptional mediator of stomatal activity in grape
Quantum Circuits for the Unitary Permutation Problem
We consider the Unitary Permutation problem which consists, given unitary
gates and a permutation of , in
applying the unitary gates in the order specified by , i.e. in
performing . 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 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 calls in
the query model and quantum switches in the new model. We
refine these results by proving that quantum switches
are necessary and sufficient to solve this problem, whereas 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 queries are required, for any
. 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
Neuromuscular evaluation in young patients with unilateral posterior crossbite before and after rapid maxillary expansion
OBJECTIVES: The aim of this study is to analyze the electromyographic and electrognatographic exams of 55 patients before and after rapid palatal expansion, and to find out a relationship between the results. MATERIALS AND METHODS: The sample consisted of 55 children (28 females and 27 males; age ranging between 6 and10 years) with unilateral posterior crossbite, and subjected to an electromyographic and electrognatographic examination before and after a rapid palatal expansion. RESULTS: By analyzing the results, it is possible to observe an increased electrical activity of the masticatory muscles (right and left masseters and anterior temporalis) both in rest position and during activities after rapid palatal expansion. CONCLUSIONS: Rapid palatal expansion produces important changes in the muscular tone and it increases the muscular activity of the masticatory muscles
Gamification and Coding to Engage Primary School Students in Learning Mathematics: A Case Study
This paper describes a pilot educational project made in a Primary School in Italy (Scuola Primaria Alessandro Manzoni at Mulazzano, Milan) implemented in 2016 and 2017. The project was born from a specific request: the school aimed at improving the results achieved by students aged 7 during the National Tests for Mathematics since they registered performances lower than the National Average. In this context, we supported teachers providing information tools and methods to improve performances. Our aim was to develop new game-oriented approaches to problem-solving, mixing our different experiences and competences (organization design, information technologies, psychology). We provided a broader spectrum of parameters tools and keys to understand how to achieve an inclusive approach personalized on students, involving them and their teachers in the project. This cooperative approach allowed us to collect interesting observations about learning styles, pointing out the negative impact that standardized processes and instruments can have on self-esteem and consequently on the performance of pupils. We argue that addressing pupils in considering mathematics as continuous research and development can increase their performances in National Tests execution. Children free to realize their own experiments and observations dramatically improve their involvement and curiosity about Mathematics
Titanium TSME appliance for patients allergic to nickel
Aim The aim of this article is to describe the use of a titanium TSME appliance for patients with allergy to resin and nickel. We aim to highlight the optimal way to avoid problems such as stomatitis and peri-labial dermatitis, which generally appear in patients who use traditional orthodontic appliances made in acrylic resin and steel. Materials and methods The construction of a titanium appliance is described and a case treated with it is reported. Results The titanium TSME presented in this paper has excellent biocompatibility due to its ability to form superficial oxides, which prevent oxidation and thus corrosion. Conclusion The non-allergic properties of titanium allow to propose it as an alternative in patients with a long-term history of allergic reactions to nichel
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