3,071 research outputs found
A new heap game
Given heaps of tokens. The moves of the 2-player game introduced
here are to either take a positive number of tokens from at most heaps,
or to remove the {\sl same} positive number of tokens from all the heaps.
We analyse this extension of Wythoff's game and provide a polynomial-time
strategy for it.Comment: To appear in Computer Games 199
Game saturation of intersecting families
We consider the following combinatorial game: two players, Fast and Slow,
claim -element subsets of alternately, one at each turn,
such that both players are allowed to pick sets that intersect all previously
claimed subsets. The game ends when there does not exist any unclaimed
-subset that meets all already claimed sets. The score of the game is the
number of sets claimed by the two players, the aim of Fast is to keep the score
as low as possible, while the aim of Slow is to postpone the game's end as long
as possible. The game saturation number is the score of the game when both
players play according to an optimal strategy. To be precise we have to
distinguish two cases depending on which player takes the first move. Let
and denote the score of
the saturation game when both players play according to an optimal strategy and
the game starts with Fast's or Slow's move, respectively. We prove that
holds
Fast Algorithm for Partial Covers in Words
A factor of a word is a cover of if every position in lies
within some occurrence of in . A word covered by thus
generalizes the idea of a repetition, that is, a word composed of exact
concatenations of . In this article we introduce a new notion of
-partial cover, which can be viewed as a relaxed variant of cover, that
is, a factor covering at least positions in . We develop a data
structure of size (where ) that can be constructed in time which we apply to compute all shortest -partial covers for a
given . We also employ it for an -time algorithm computing
a shortest -partial cover for each
Palindromic complexity of trees
We consider finite trees with edges labeled by letters on a finite alphabet
. Each pair of nodes defines a unique labeled path whose trace is a
word of the free monoid . The set of all such words defines the
language of the tree. In this paper, we investigate the palindromic complexity
of trees and provide hints for an upper bound on the number of distinct
palindromes in the language of a tree.Comment: Submitted to the conference DLT201
Predicting synthetic rescues in metabolic networks
An important goal of medical research is to develop methods to recover the
loss of cellular function due to mutations and other defects. Many approaches
based on gene therapy aim to repair the defective gene or to insert genes with
compensatory function. Here, we propose an alternative, network-based strategy
that aims to restore biological function by forcing the cell to either bypass
the functions affected by the defective gene, or to compensate for the lost
function. Focusing on the metabolism of single-cell organisms, we
computationally study mutants that lack an essential enzyme, and thus are
unable to grow or have a significantly reduced growth rate. We show that
several of these mutants can be turned into viable organisms through additional
gene deletions that restore their growth rate. In a rather counterintuitive
fashion, this is achieved via additional damage to the metabolic network. Using
flux balance-based approaches, we identify a number of synthetically viable
gene pairs, in which the removal of one enzyme-encoding gene results in a
nonviable phenotype, while the deletion of a second enzyme-encoding gene
rescues the organism. The systematic network-based identification of
compensatory rescue effects may open new avenues for genetic interventions.Comment: Supplementary Information is available at the Molecular Systems
Biology website: http://www.nature.com/msb/journal/v4/n1/full/msb20081.htm
La Germania alla prova del coronavirus tra Stato di diritto e misure emergenziali
Il lavoro analizza le strategie adottate in Germania per contrastare la pandemia COVID-19. L\u2019analisi si articola su due filoni: da un lato si approfondiscono le misure per il contenimento della diffusione dei contagi, dall\u2019altro quelle volte ad arginare le ricadute economiche della pandemia. L\u2019emergenza ha rappresentato anche per la Germania un vero e proprio stress test, mettendo a dura prova sia il riparto federale delle competenze, sia le istituzioni democratiche e la salvaguardia dei diritti fondamentali come elemento qualificante dello Stato di diritto
Psychological, social and biological correlates of body perception disturbance in complex regional pain syndrome
Body Perception Disturbance (BPD) in Complex Regional Pain Syndrome (CRPS) still represents a poorly understood phenomenon. Research has shown that knowledge about changes in body perception can yield relevant information for understanding and treating the disease. This study addressed possible connections between BPD and psychological and social factors, pain intensity, and disease duration. Sixty patients with chronic CRPS Type I of the hand were recruited. Body Perception Disturbance was assessed using the Galer and Jensen Neurobehavioral Questionnaire (GJ) and the BATH CRPS Body Perception Disturbance Scale (BATH). Depression, anxiety, stress, childhood trauma and other life events were assessed using standardized and validated questionnaires. This study found that BPD in CRPS was significantly correlated with measures of depression, anxiety, current stress, quality of life, and pain intensity, but not with stress experienced in the twelve months preceding onset of illness, childhood trauma, or duration of illness. Future research needs to identify which patients are most likely to develop these psychological conditions of CRPS, so that early, preventive intervention is possible. This study establishes a relationship between depression, anxiety, current stress, quality of life, pain intensity, and BPD severity. It also supports literature suggesting that preexisting stress, childhood trauma, and disease duration have no influence on BPD. The findings suggest that there is a bidirectional influence between brain alterations, psychological symptoms, and illness severity
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