113 research outputs found
Quantum Lower and Upper Bounds for 2D-Grid and Dyck Language
We study the quantum query complexity of two problems.
First, we consider the problem of determining if a sequence of parentheses is a properly balanced one (a Dyck word), with a depth of at most k. We call this the Dyck_{k,n} problem. We prove a lower bound of ?(c^k ?n), showing that the complexity of this problem increases exponentially in k. Here n is the length of the word. When k is a constant, this is interesting as a representative example of star-free languages for which a surprising O?(?n) query quantum algorithm was recently constructed by Aaronson et al. [Scott Aaronson et al., 2018]. Their proof does not give rise to a general algorithm. When k is not a constant, Dyck_{k,n} is not context-free. We give an algorithm with O(?n(log n)^{0.5k}) quantum queries for Dyck_{k,n} for all k. This is better than the trival upper bound n for k = o({log(n)}/{log log n}).
Second, we consider connectivity problems on grid graphs in 2 dimensions, if some of the edges of the grid may be missing. By embedding the "balanced parentheses" problem into the grid, we show a lower bound of ?(n^{1.5-?}) for the directed 2D grid and ?(n^{2-?}) for the undirected 2D grid. The directed problem is interesting as a black-box model for a class of classical dynamic programming strategies including the one that is usually used for the well-known edit distance problem. We also show a generalization of this result to more than 2 dimensions
ProuÄavanje 194Ir uhvatom termiÄkih neutrona I (d, p) reakcijom
Levels of 194Ir were studied using thermal neutron capture reaction. A pair spectrometer was used to measure the high-energy Ī³-ray spectrum from thermal-neutron capture in enriched 193Ir target over the energy range 4640 - 6100 keV. The low-energy Ī³-radiation from the reaction was studied with crystal diffraction spectrometers, and conversion electrons were observed with magnetic spectrometers. The high-sensitivity measurements at the Grenoble reactor, evaluated for transition energies up to 500 keV, are compared with lower-sensitivity measurements at the Wuerenlingen and Salaspils reactors. The comparison helped to obtain reliable isotopic identification for a number of 194Ir lines. The multipolarity admixtures for 29 Ī³-transitions were determined on the basis of conversion lines from different electron subshells. Prompt and delayed Ī³-Ī³ coincidences were measured using semiconductor and scintillation detectors. The 193Ir(d,p) high-resolution spectra, observed with a magnetic spectrometer, are given. All these data contributed to establishing a detailed level scheme of 194Ir. Additional data and the interpretation of the results in terms of current models will be presented in a forthcoming paper.ProuÄavala su se stanja u 194Ir reakcijama 193Ir(n, Ī³) i 193Ir(d, p). Mjerenja uhvata termiÄkih neutrona naÄinjena su uz reaktore u Grenoblu, Wuerenlingenu i Salapsisu. Za mjerenja Ī³-zraÄenja visoke energije upotrebljavao se spektrometar parova, a za niske energije difraktometar. Konverzijske elektrone se mjerilo magnetskim spektrometrom. Mjerenja reakcije (d, p) visokog razluÄivanja izvedena su magnetskim spektrometrom. Usporedbe tih mjerenja omoguÄile su pouzdano izotopno prepoznavanje prijelaza u 194 Ir, a spektri konverzijskih elektrona i odreÄivanje multipolnosti prijelaza. Dobiveni su podaci osnova sheme raspada 194Ir
ProuÄavanje 194Ir uhvatom termiÄkih neutrona I (d, p) reakcijom
Levels of 194Ir were studied using thermal neutron capture reaction. A pair spectrometer was used to measure the high-energy Ī³-ray spectrum from thermal-neutron capture in enriched 193Ir target over the energy range 4640 - 6100 keV. The low-energy Ī³-radiation from the reaction was studied with crystal diffraction spectrometers, and conversion electrons were observed with magnetic spectrometers. The high-sensitivity measurements at the Grenoble reactor, evaluated for transition energies up to 500 keV, are compared with lower-sensitivity measurements at the Wuerenlingen and Salaspils reactors. The comparison helped to obtain reliable isotopic identification for a number of 194Ir lines. The multipolarity admixtures for 29 Ī³-transitions were determined on the basis of conversion lines from different electron subshells. Prompt and delayed Ī³-Ī³ coincidences were measured using semiconductor and scintillation detectors. The 193Ir(d,p) high-resolution spectra, observed with a magnetic spectrometer, are given. All these data contributed to establishing a detailed level scheme of 194Ir. Additional data and the interpretation of the results in terms of current models will be presented in a forthcoming paper.ProuÄavala su se stanja u 194Ir reakcijama 193Ir(n, Ī³) i 193Ir(d, p). Mjerenja uhvata termiÄkih neutrona naÄinjena su uz reaktore u Grenoblu, Wuerenlingenu i Salapsisu. Za mjerenja Ī³-zraÄenja visoke energije upotrebljavao se spektrometar parova, a za niske energije difraktometar. Konverzijske elektrone se mjerilo magnetskim spektrometrom. Mjerenja reakcije (d, p) visokog razluÄivanja izvedena su magnetskim spektrometrom. Usporedbe tih mjerenja omoguÄile su pouzdano izotopno prepoznavanje prijelaza u 194 Ir, a spektri konverzijskih elektrona i odreÄivanje multipolnosti prijelaza. Dobiveni su podaci osnova sheme raspada 194Ir
Sonification and Music as Support to the Communication of Alcohol-Related Health Risks to Young People : Study design and results
Excessive consumption of alcohol has been recognised as a significant risk factor impacting the health of young people. Effective communication of such risk is considered to be one key step to improve behaviour. We evaluated an innovative multimedia intervention that utilised audio (sonificationāusing sound to display dataāand music) and interactivity to support the visual communication of alcohol health risk data. A 3-arm pilot experiment was undertaken. The trial measures included health knowledge, alcohol risk perception and user experience of the intervention. Ninety-six subjects participated in the experiment. At 1 month follow-up, alcohol knowledge and alcohol risk perception improved significantly in the whole sample. However, there was no difference between the intervention groups that experienced (1) visual presentation with interactivity (VI-Exp group) and, (2) visual presentation with audio (sonification and music) and interactivity (VAI-Exp group), when compared to the control group which experienced a (3) visual only presentation (V-Cont group). Participants reported enjoying the presentations and found them educational. The majority of participants indicated that the audio, music and sonification helped to convey the information well, and, although a larger sample size is needed to fully establish the effectiveness of the different interventions, this study provides a useful model for future similar studies
Altered orbitofrontal sulcogyral patterns in gambling disorder: a multicenter study
Gambling disorder is a serious psychiatric condition characterized by decision-making and reward processing
impairments that are associated with dysfunctional brain activity in the orbitofrontal cortex (OFC). However, it remains
unclear whether OFC functional abnormalities in gambling disorder are accompanied by structural abnormalities. We
addressed this question by examining the organization of sulci and gyri in the OFC. This organization is in place very
early and stable across life, such that OFC sulcogyral patterns (classified into Types I, II, and III) can be regarded as
potential pre-morbid markers of pathological conditions. We gathered structural brain data from nine existing studies,
reaching a total of 165 individuals with gambling disorder and 159 healthy controls. Our results, supported by both
frequentist and Bayesian statistics, show that the distribution of OFC sulcogyral patterns is skewed in individuals with
gambling disorder, with an increased prevalence of Type II pattern compared with healthy controls. Examination of
gambling severity did not reveal any significant relationship between OFC sulcogyral patterns and disease severity.
Altogether, our results provide evidence for a skewed distribution of OFC sulcogyral patterns in gambling disorder and
suggest that pattern Type II might represent a pre-morbid structural brain marker of the disease. It will be important to
investigate more closely the functional implications of these structural abnormalities in future work.Y.L. was supported by the National Natural Science Foundation of China (Grant
No. 31600929) and the Fundamental Research Funds for the Central
Universities (010914380002). G.S. was supported by a Veni grant from the
Netherlands Organization for Scientific Research (Grant No. 016.155.218). J.J.
was supported by the Academy of Finland (Grant No. 295580), the Finnish
Medical Foundation, and the Finnish Foundation for Alcohol Studies. V.K. was
supported by the Academy of Finland (Grant No. 256836) and the Finnish
Foundation for Alcohol Studies. S.G. and H.R.S. were supported by the Danish
Council for Independent Research in Social Sciences through a grant to
Thomas RamsĆøy (āDecision Neuroscience Projectā; Grant No. 0601-01361B) and
by the Lundbeck Foundation through a Grant of Excellence (āContActā; Grant
No. R59 A5399). A.G. was supported by Deutsche Forschungsgemeinschaft
(DFG) HE2597/15ā1, HE2597/15ā2, and DFG Graduiertenkolleg 1589/2 āSensory
Computation in Neural Systemsā. N.R.-S. was supported by a research grant by
the Senatsverwaltung fĆ¼r Gesundheit und Soziales, Berlin, Germany (Grant No.
002ā2008/I B 35). C.M.R.d.L. and J.C.P. were supported by a grant from the
Spanish Government (Ministerio de EconomĆa y Competitividad, SecretarĆa de
Estado de InvestigaciĆ³n, Desarrollo e InnovaciĆ³n; Convocatoria 2017 de
Proyectos I+D de Excelencia, Spain; co-funded by the Fondo Europeo de
Desarrollo Regional, FEDER, European Union; Grant No. PSI2017ā85488-P). J.-C.
D. was supported by āLABEX ANR-11-LABEX-0042ā of UniversitĆ© de Lyon within
the program Investissements dāAvenir (ANR-11-IDEX-007) operated by the
French National Research Agency and by a grant from the Fondation pour la
Recherche MĆ©dicale (Grant No. DPA20140629796)
The Impact of Social Disparity on Prefrontal Function in Childhood
The prefrontal cortex (PFC) develops from birth through late adolescence. This extended developmental trajectory provides many opportunities for experience to shape the structure and function of the PFC. To date, a few studies have reported links between parental socioeconomic status (SES) and prefrontal function in childhood, raising the possibility that aspects of environment associated with SES impact prefrontal function. Considering that behavioral measures of prefrontal function are associated with learning across multiple domains, this is an important area of investigation. In this study, we used fMRI to replicate previous findings, demonstrating an association between parental SES and PFC function during childhood. In addition, we present two hypothetical mechanisms by which SES could come to affect PFC function of this association: language environment and stress reactivity. We measured language use in the home environment and change in salivary cortisol before and after fMRI scanning. Complexity of family language, but not the child's own language use, was associated with both parental SES and PFC activation. Change in salivary cortisol was also associated with both SES and PFC activation. These observed associations emphasize the importance of both enrichment and adversity-reduction interventions in creating good developmental environments for all children
Perceptual Load-Dependent Neural Correlates of Distractor Interference Inhibition
The load theory of selective attention hypothesizes that distractor interference is suppressed after perceptual processing (i.e., in the later stage of central processing) at low perceptual load of the central task, but in the early stage of perceptual processing at high perceptual load. Consistently, studies on the neural correlates of attention have found a smaller distractor-related activation in the sensory cortex at high relative to low perceptual load. However, it is not clear whether the distractor-related activation in brain regions linked to later stages of central processing (e.g., in the frontostriatal circuits) is also smaller at high rather than low perceptual load, as might be predicted based on the load theory.We studied 24 healthy participants using functional magnetic resonance imaging (fMRI) during a visual target identification task with two perceptual loads (low vs. high). Participants showed distractor-related increases in activation in the midbrain, striatum, occipital and medial and lateral prefrontal cortices at low load, but distractor-related decreases in activation in the midbrain ventral tegmental area and substantia nigra (VTA/SN), striatum, thalamus, and extensive sensory cortices at high load.Multiple levels of central processing involving midbrain and frontostriatal circuits participate in suppressing distractor interference at either low or high perceptual load. For suppressing distractor interference, the processing of sensory inputs in both early and late stages of central processing are enhanced at low load but inhibited at high load
Reward-Related Dorsal Striatal Activity Differences between Former and Current Cocaine Dependent Individuals during an Interactive Competitive Game
Cocaine addiction is characterized by impulsivity, impaired social relationships, and abnormal mesocorticolimbic reward processing, but their interrelationships relative to stages of cocaine addiction are unclear. We assessed blood-oxygenation-level dependent (BOLD) signal in ventral and dorsal striatum during functional magnetic resonance imaging (fMRI) in current (CCD; nā=ā30) and former (FCD; nā=ā28) cocaine dependent subjects as well as healthy control (HC; nā=ā31) subjects while playing an interactive competitive Domino game involving risk-taking and reward/punishment processing. Out-of-scanner impulsivity-related measures were also collected. Although both FCD and CCD subjects scored significantly higher on impulsivity-related measures than did HC subjects, only FCD subjects had differences in striatal activation, specifically showing hypoactivation during their response to gains versus losses in right dorsal caudate, a brain region linked to habituation, cocaine craving and addiction maintenance. Right caudate activity in FCD subjects also correlated negatively with impulsivity-related measures of self-reported compulsivity and sensitivity to reward. These findings suggest that remitted cocaine dependence is associated with striatal dysfunction during social reward processing in a manner linked to compulsivity and reward sensitivity measures. Future research should investigate the extent to which such differences might reflect underlying vulnerabilities linked to cocaine-using propensities (e.g., relapses)
LU 76. konference: tÄzes un raksti
KrÄjumu veido LU Filozofijas un socioloÄ£ijas institÅ«ta pÄtnieku Latvijas UniversitÄtes 76. starptautiskÄs zinÄtniskÄs konferences sekciju darbÄ 2018. gada 15. un 16. februÄrÄ« nolasÄ«to prioritÄrajam projektam āKritiskÄ domÄÅ”ana, inovÄcija, konkurÄtspÄja un globalizÄcijaā veltÄ«to referÄtu tÄzes, kÄ arÄ« vairÄki raksti, kuri tapuÅ”i uz Å”ajÄ konferencÄ nolasÄ«to referÄtu pamata.
LU FSI pÄtniekiem konference bija ne tikai atskaite par otrajÄ pÄtniecÄ«bas gadÄ projektÄ paveikto, bet tajÄ pÄtnieki diskutÄja arÄ« par to, kÄ paplaÅ”inÄt pÄtÄmo tÄmu loku, pievÄrÅ”oties vairÄkiem Latvijas sabiedrÄ«bai aktuÄliem jautÄjumiem. PiemÄram, ja Filozofijas un socioloÄ£ijas institÅ«ta filozofi projekta 1. posma noslÄguma seminÄrÄ pÄrsvarÄ diskutÄja par kritiskÄs domÄÅ”anas konceptu un tÄs lietojuma iespÄjÄm, tad LU 76. konferencÄ jau iezÄ«mÄjÄs noturÄ«ga interese par kritiskÄs domÄÅ”anas un medijpratÄ«bas sasaisti, kas 2018. gada beigÄs noslÄdzÄs ar ekspertu seminÄru cikla organizÄÅ”anu sadarbÄ«bÄ ar Eiropas Kopienas pÄrstÄvniecÄ«bu LatvijÄ. VairÄki pÄtnieki pievÄrsÄs jautÄjumam par inovÄcijas iespÄjÄm humanitÄrajÄs zinÄtnÄs utt.
Konferences referÄti atspoguļoja dažÄdas pieejas un metodoloÄ£ijas, sniedzot ieskatu vÄl nepabeigtajos pÄtÄ«jumos, bet tikai to norisÄ un pirmajos rezultÄtos. PÄtÄ«jumu gaitai lasÄ«tÄjs aicinÄts sekot turpmÄkajÄs LU FSI pÄtnieku zinÄtniskajÄs publikÄcijÄs
- ā¦