The impact of balancing on problem hardness in a highly structured domain

Random problem distributions have played a key role in the study and design of algorithms for constraint satisfaction and Boolean satisfiability, as well as in ourunderstanding of problem hardness, beyond standard worst-case complexity. We consider random problem distributions from a highly structured problem domain that generalizes the Quasigroup Completion problem (QCP) and Quasigroup with Holes (QWH), a widely used domain that captures the structure underlying a range of real-world applications. Our problem domain is also a generalization of the well-known Sudoku puz- zle: we consider Sudoku instances of arbitrary order, with the additional generalization that the block regions can have rectangular shape, in addition to the standard square shape. We evaluate the computational hardness of Generalized Sudoku instances, for different parameter settings. Our experimental hardness results show that we can generate instances that are considerably harder than QCP/QWH instances of the same size. More interestingly, we show the impact of different balancing strategies on problem hardness. We also provide insights into backbone variables in Generalized Sudoku instances and how they correlate to problem hardness.

Spanish adaptation of the Expectancy Questionnaire (EQ) about alcohol effects in adolescents

Background: Alcohol-related expectancies are especially relevant in relation to alcohol consumption during adolescence. The main aim of this study was to adapt and translate into Spanish (Castilian) the Expectancy Questionnaire (EQ), and to study its psychometric properties in adolescents. Method: The sample was composed of 514 adolescents (57.20% female, mean age = 15.21; SD = .63) who completed the EQ and the alcohol consumption questionnaire AIS-UJI. Results: Confi rmatory factor analysis indicated that an eight-factor model, grouped into two general factors of positive and negative expectancies, had acceptable fi t indices. Cronbach’s alphas ranged from .75 to .96. Finally, the structural equation model showed that positive expectancies were positively related to alcohol use, whereas negative expectancies were negatively related to drinking. Conclusions: Results showed that the Spanish version of the EQ for adolescents is a valid and reliable questionnaire to measure expectancies about alcohol effects.

Mobile terminal adaptation in portal for better usability

Elektroniset finanssipalvelut, erityisesti Internetin kautta käytettynä, on kasvava alue. Elektronisten finanssipalveluiden tarjoajan tulee pystyä tarjoamaan laaja käytettävyys kaikkien kanavien kautta. Laajan käytettävyyden avulla asiakas voi valita haluamansa kanavan haluamanaan aikana. Palveluntarjoajalla tulee olla joustava arkkitehtuuri pystyäkseen tukemaan asiakkaiden muuttuvia vaatimuksia. Joustavalla arkkitehtuurilla päätelaitteeseen mukautuminen on mahdollista ja näin palveluntarjoaja pystyy tarjoamaan tuen monille eri päätelaitteille ja teknologioille helposti ja nopeasti. Diplomityö keskittyy tutkimaan mahdollisuutta monen kanavan tukeen ja päätelaitteeseen mukautumista Nordean tulevassa finanssiportaaliratkaisussa. Tämä pitäisi olla mahdollista uuden arkkitehtuurin kanssa, jonka TietoEnator on toteuttanut yhteistyössä Nordean kanssa. Sivujen rakenteen uudelleenjärjestelyillä saatiin hyviä tuloksia. Nykyisestä arkkitehtuurissa löydettiin myös puutteita ja jäljelle jäi avoimia kysymyksiä, jotka kirjattiin ylös. On selvästi nähtävissä, että tehokas päätelaitteeseen mukautuminen ja tuki monelle kanavalle tuo hyötyjä sekä pankille että asiakkaalle.

Langevin equations with multiplicative noise: Application to domain growth

Langevin Equations of Ginzburg-Landau form, with multiplicative noise, are proposed to study the effects of fluctuations in domain growth. These equations are derived from a coarse-grained methodology. The Cahn-Hiliard-Cook linear stability analysis predicts some effects in the transitory regime. We also derive numerical algorithms for the computer simulation of these equations. The numerical results corroborate the analytical predictions of the linear analysis. We also present simulation results for spinodal decomposition at large times.

IPSec in 3G packet switched domain

Diplomityö käsittelee IPSec-protokollan (IP Security Protocol) implementointia UMTS:n (Universal Mobile Telecommunications System) pakettikytkentäiseen verkkoon. Runkoverkkoa käytetään mobiilikäyttäjän datan siirtämiseen sekä verkkoelementtien väliseen ohjausinformaation välitykseen. Koska UMTS:n runkoverkot ovat IP-pakettikytkentäisiä verkkoja, IPSec-protokollaa voidaan käyttää lähetettyjen IP-datasähkeiden suojaamiseen. IPSec- ja IKE-protokollien (Internet Key Exchange) käyttö on koettu monimutkaiseksi kiinteissä verkoissa. Tämän saman ongelman edessä tulevat olemaan myös operaattorit, kun he alkavat rakentaa UMTS-verkkojaan. On kuitenkin muistettava se, että tulevaisuudessa lähes kaikki data mukaanlukien ääni ja video on tarkoitus siirtää IP-protokollan avulla. IP-teknologiaan perustuva tiedonsiirron kasvu lisää IPSec-protokollan merkitystä ei ainoastaan runkoverkossa mutta myös radioliityntäverkoissa sekä SS7-merkinantoverkoissa (Signaling System No. 7). Diplomityö on tehty osaksi diplomi-insinöörin tutkintoa Lappeenrannan teknillisessä yliopistossa. Työ on tehty Nokia Networksin palveluksessa Helsingissä, vuosien 2002 ja 2003 välisenä aikana.

Differential Dimerization of Variants Linked to Enhanced S-Cone Sensitivity Syndrome (ESCS) Located in the NR2E3 Ligand-Binding Domain.

NR2E3 encodes the photoreceptor-specific nuclear hormone receptor that acts as a repressor of cone-specific gene expression in rod photoreceptors, and as an activator of several rod-specific genes. Recessive variants located in the ligand-binding domain (LBD) of NR2E3 cause enhanced short wavelength sensitive- (S-) cone syndrome (ESCS), a retinal degeneration characterized by an excess of S-cones and non-functional rods. We analyzed the dimerization properties of NR2E3 and the effect of disease-causing LBD missense variants by bioluminescence resonance energy transfer (BRET(2) ) protein interaction assays. Homodimerization was not affected in presence of p.A256V, p.R039G, p.R311Q, and p.R334G variants, but abolished in presence of p.L263P, p.L336P, p.L353V, p.R385P, and p.M407K variants. Homology modeling predicted structural changes induced by NR2E3 LBD variants. NR2E3 LBD variants did not affect interaction with CRX, but with NRL and rev-erbα/NR1D1. CRX and NRL heterodimerized more efficiently together, than did either with NR2E3. NR2E3 did not heterodimerize with TLX/NR2E1 and RXRα/NR2C1. The identification of a new compound heterozygous patient with detectable rod function, who expressed solely the p.A256V variant protein, suggests a correlation between LBD variants able to form functional NR2E3 dimers and atypical mild forms of ESCS with residual rod function.

Ras-association domain of sorting nexin 27 is critical for regulating expression of GIRK potassium channels

G protein-gated inwardly rectifying potassium (GIRK) channels play an important role in regulating neuronal excitability. Sorting nexin 27b (SNX27b), which reduces surface expression of GIRK channels through a PDZ domain interaction, contains a putative Ras-association (RA) domain with unknown function. Deleting the RA domain in SNX27b (SNX27b-DRA) prevents the down-regulation of GIRK2c/GIRK3 channels. Similarly, a point mutation (K305A) in the RA domain disrupts regulation of GIRK2c/GIRK3 channels and reduces H-Ras binding in vitro. Finally, the dominant-negative H-Ras (S17N) occludes the SNX27b-dependent decrease in surface expression of GIRK2c/GIRK3 channels. Thus, the presence of a functional RA domain and the interaction with Ras-like G proteins comprise a novel mechanism for modulating SNX27b control of GIRK channel surface expression and cellular excitability.

Worldwide Population Structure, Long-Term Demography, and Local Adaptation of Helicobacter pylori.

Helicobacter pylori is an important human pathogen associated with serious gastric diseases. Owing to its medical importance and close relationship with its human host, understanding genomic patterns of global and local adaptation in H. pylori may be of particular significance for both clinical and evolutionary studies. Here we present the first such whole genome analysis of 60 globally distributed strains, from which we inferred worldwide population structure and demographic history and shed light on interesting global and local events of positive selection, with particular emphasis on the evolution of San-associated lineages. Our results indicate a more ancient origin for the association of humans and H. pylori than previously thought. We identify several important perspectives for future clinical research on candidate selected regions that include both previously characterized genes (e.g., transcription elongation factor NusA and tumor necrosis factor alpha-inducing protein Tipα) and hitherto unknown functional genes.

La chute comme événement du parcours de vie : signification, conséquences, adaptation et prévention

La chute chez les personnes âgées est considérée comme un problème de santé publique en raison de sa fréquence, de ses conséquences ainsi que de l'efficacité de certain programmes de prévention. La chute est pourtant très souvent non signalée par les personnes ou par les professionnels. Je postule que la chute est un événement traumatisant ; j'examine d'une part son impact sur les trajectoires de personnes à partir de 50 ans et d'autre part l'adaptation à cet événement. Mobilisant différents types de données existantes, ce travail met en évidence les nombreux impacts de la chute au-delà de la santé, et notamment sur les dimensions sociales et sur la qualité de vie ; en comparaison à d'autres événements de santé, la chute présente un effet sur plusieurs indicateurs qui s'exprime tant à court qu'à long terme. J'identifie des facteurs de vulnérabilité à la chute : le moment de survenue de l'événement est un critère déterminant, l'adaptation étant plus difficile quand la chute survient chez des moins de 65 ans ; la gravité de l'événement entrave également la probabilité de s'y adapter. Par contre, les ressources institutionnelles sont sous-utilisées par les personnes concernées et les effets d'un programme généraliste de prévention des chutes fondé sur de l'activité physique et de l'éducation pour la santé sont modestes et ne se maintiennent pas au-delà de l'intervention. Au final, cette thèse apporte une contribution originale à l'étude psychosociale de la chute envisagée au moyen du modèle de la vulnérabilité : ses conclusions permettent d'ajuster des interventions qui devraient prioritairement viser à renforcer les ressources et stratégies individuelles et ensuite à gérer les conséquences identitaires et émotionnelles liées à la chute.

On the origin of the selectivity of plasmidic H-NS towards horizontally acquired DNA: Linking H-NS oligomerization and cooperative DNA binding

The nucleoid-associated protein H-NS is a global modulator of the expression of genes associated with adaptation to environmental changes. A variant of H-NS expressed in the R27 plasmid was previously shown to selectively modulate the expression of horizontally acquired genes, with minimal effects on core genes that are repressed by the chromosomal form of H-NS. Both H-NS proteins are formed by an oligomerization domain and a DNA-binding domain, which are connected by a linker that is highly flexible in the absence of DNA. We studied DNA binding by means of oligomer-forming chimeric proteins in which domains of the chromosomal and plasmidic variants are exchanged, as well as in monomeric truncated forms containing the DNA-binding domain and variable portions of the linker. Point mutations in the linker were also examined in full-length and truncated H-NS constructs. These experiments show that the linker region contributes to DNA binding affinity and that it is a main component of the distinct DNA binding properties of chromosomal and plasmidic H-NS. We propose that interactions between the linker and DNA limit the flexibility of the connection between H- NS oligomerization and DNA binding and provide an allosteric indirect readout mechanism to detect long- range distortions of DNA, thus enabling discrimination between core and horizontally acquired DNA.

Computational toolbox towards evolutionary domain mapping of membrane proteins

Membrane proteins account for about 20% to 30% of all proteins encoded in a typical genome. They play central roles in multiple cellular processes mediating the interaction of the cell with its surrounding. Over 60% of all drug targets contain a membrane domain. The experimental difficulties of obtaining a crystal structural severely limits our ability or understanding of membrane protein function. Computational evolutionary studies of proteins are crucial for the prediction of 3D structures. In this project, we construct a tool able to quantify the evolutionary positive selective pressure on each residue of membrane proteins through maximum likelihood phylogeny reconstruction. The conservation plot combined with a structural homology model is also a potent tool to predict those residues that have essentials roles in the structure and function of a membrane protein and can be very useful in the design of validation experiments.