Testing a frequency of exposure hypothesis in attentional bias for alcohol-related stimuli amongst social drinkers

Aims To examine whether a group of social drinkers showed longer response latencies to alcohol-related stimuli than neutral stimuli and to test whether exposure to 1) an alcohol-related environment and 2) consumption related cues influenced the interference from alcohol-related stimuli. Methods A 2 × 2 × 2 × 5 factorial design with Exposure Group (high, low) and Consumption Group (high, low) as between-participant factors and Word Type (alcohol, neutral) and Block (1–5) as within-participant factors was used. Forty-three undergraduate university students, 21 assigned to a high exposure group and 22 to a low exposure group, took part in the experiment. Exposure Group was defined according to whether or not participants currently worked in a bar or pub. Consumption Group was defined according to a median split on a quantity–frequency measure derived from two questions of the Alcohol Use Disorders Identification Test (AUDIT) questionnaire. A modified computerised Stroop colour naming test was used to measure response latencies. Results Exposure and consumption factors interacted to produce greater interference from alcohol-related stimuli. In particular, the low consumption group showed interference from alcohol-related stimuli only in the high exposure condition. Exposure did not affect the magnitude of interference in the high consumption group. Conclusions Attentional bias is dependent upon exposure to distinct types of alcohol-related cues

Heart rate variability is associated with amygdala functional connectivity with MPFC across younger and older adults

The ability to regulate emotion is crucial to promote well-being. Evidence suggests that the medial prefrontal cortex (mPFC) and adjacent anterior cingulate (ACC) modulate amygdala activity during emotion regulation. Yet less is known about whether the amygdala-mPFC circuit is linked with regulation of the autonomic nervous system and whether the relationship differs across the adult lifespan. The current study tested the hypothesis that heart rate variability (HRV) reflects the strength of mPFC-amygdala interaction across younger and older adults. We recorded participants’ heart rates at baseline and examined whether baseline HRV was associated with amygdala-mPFC functional connectivity during rest. We found that higher HRV was associated with stronger functional connectivity between the amygdala and the mPFC during rest across younger and older adults. In addition to this age-invariant pattern, there was an age-related change, such that greater HRV was linked with stronger functional connectivity between amygdala and ventrolateral PFC (vlPFC) in younger than in older adults. These results are in line with past evidence that vlPFC is involved in emotion regulation especially in younger adults. Taken together, our results support the neurovisceral integration model and suggest that higher heart rate variability is associated with neural mechanisms that support successful emotional regulation across the adult lifespan

Tryptophan Depletion Affects Heart Rate Variability and Impulsivity in Remitted Depressed Patients with a History of Suicidal Ideation

Cardiale disfunctie en ritmestoornisse

Determining bone types in X-ray images

Greining fjallar um tölvukerfi sem lærir af myndum af kjúklingabringum, hvernig á að þekkja uppruna beinanna sem birtast á þeim.This thesis describes a system implemented to identify bone types in X-ray images of chicken fillets. The system has two key aspects, learning and judging. When learning, the system scans an image and extracts numerical information from it. The type of bone is then manually identified and matched to the statistical information. Following the learning phase the derived data is projected into a multidimensional space where each variable of the bone is paired to a specific dimension. Each spatial dimension is then presented with a single array in code. When judging, the system extracts the numerical information from a new image of an unspecified type. This numerical information is then equated to a location in the already filled multi-dimensional space. How inclined towards a specific type of bone the vicinity of this location is, gives information on how likely it is that the bone is of that given type. In order to determine the relative weight of each dimension, the dimensions were merged into categories. The categories were then merged into the total outcome. Dimensions were merged into categories using methods manually determined in each case whereas when merging categories into outcome the categories weight were incremented, one after another and using that weighing the whole system was run through and the correct number of images recorded. At last he weighting combination with the best total outcome was selected. The system correctly predicted the bone type for 41 out of 42 images, which is an accuracy of around 98%. This is a rather good result, especially considering that the system only had 42 images to learn from. These numbers must be taken with caution though because the dimensional weights were determined afterwards.Mare

Verðmat. Helstu aðferðir

Þessari ritgerð er ætlað að lýsa helstu aðferðum sem notaðar eru við að verðmeta fyrirtæki, bæði þau sem eru skráð á hlutabréfamarkað sem og þau sem eru óskráð. Farið verður yfir helstu atriði þessarra mála ásamt því að greina helstu áhættuþætti og áhrifavalda. Í ritgerðinni er farið yfir framkvæmd og aðferðir sem notaðar eru við slíkt verðmat ásamt því að sérstakur gaumur verður gefinn þeirri aðferð sem nefnist frjálst sjóðsstreymi. Þá verður litið á verðmat á fyrirtæki sem er skráð á skipulagðan verðbréfamarkað. Sú aðferð sem notuð verður er frjáls sjóðsstreymisaðferð og fyrirtækið sem hún er notuð á er Icelandair Group. Verðmatið sjálft, ásamt ítarlegri útreikningum má finna í viðaukum

Stafrænu fötin keisarans : könnun á kauphegðun tölvuleikjaspilara á stafrænum leikmunum

Framleiðendur tölvuleikja selja ekki einungis tölvuleiki, þeir selja líka stafræna leikmuni (e. digital props) sem geta haft áhrif á spilun leiksins eða breytt útlitinu á persónunni sem að notandi leiksins spilar. En hverjir eru það sem kaupa stafræna leikmuni aðeins útlitsins vegna og hvaða þættir einkenna þá sem kaupendur? Markmiðið með þessari rannsókn var að komast að því hverjir versla stafræna leikmuni og að finna þá þætti sem að einkenna þá. Nýttar voru heimildir um neytendahegðun, ferli kaupákvörðunar og hópmyndun á markaði með áherslu á kaup stafrænna leikmuna. Rannsóknaráherslan var EVE Online fjölspilunarleikurinn (e. massively multiplayer online role-playing game/mmorpg) og sala stafrænna leikmuna sem ekki hafa beint notagildi innan leiksins. Könnun var lögð fyrir fyrrverandi og núverandi notendur leiksins og skoðuð var fylgni á milli kaupa stafræna leikmuna og tíma sem notendur eyddu í spilun leiksins, vörumerkjatryggð, mismunandi spilastíl notenda, hópmyndun á markaði, aldur, stöðu og kyn. Þessi rannsókn var gerð til þess að auka þekkingu á sviði neytendahegðunar gagnvart stafrænum leikmunum í tölvuleikjum. Gögnin úr könnuninni voru skoðuð til þess að finna þá þætti sem einkenna neytendur sem kaupa stafræna leikmuni sem hafa ekki beint notagildi.Tvær af fimm tilgátunum sem lagaðar voru fyrir stóðust. H2: notendur sem þekkja aðra notendur sem hafa keypt stafræna leikmuni sem hafa ekki beint notagildi eru líklegri til að kaupa stafræna leikmuni sem hafa ekki beint notagildi ( (1, N = 533) = 49.753, p = < .001), það var miðlungs áhrifastærð (Cramer’s Phi = .306). Hin tilgátan; H4: notendur sem fylgja leiknum, EVE Online, á samfélagsmiðlum eru líklegri til að kaupa stafræna leikmuni sem hafa ekki beint notagildi ( (3, N = 531) = 24.772, p = < .001), það var líka miðlungs áhrifastærð (Cramer’s Phi = .216). Niðurstöðurnar benda til þess að notendur versli þessa stafrænu leikmuni af félagslegum ástæðum. Mögulega sem stöðutákn eða til þess að tilheyra eða aðgreina sig frá öðrum hópum notenda innan leiksins. Lykilorð: Stafrænir leikmunir, neytendahegðun, fjölspilunarleikir, EVE OnlineProducers of video games don´t just sell games, they also sell digital props that can affect the game itself or change aesthetic elements in the game e.g. the appearance of the players' avatars. Who are the consumers which buy aesthetical digital props and which factors define them? The aim of this study was to discover what kind of consumer purchases aesthetic digital props within games and to find the factors that define them. The literature regarding consumer behavior, consumer buying processes and grouping in the market was reviewed with a focus on the purchase of digital props. The focus of this study was the mmorpg EVE Online and the sale of digital props within the game. A survey was conducted amongst both current and former players of the game to find out if any correlation existed between the purchase of aesthetic digital props and the time the users spent playing the game, brand loyalty, different types of play styles, grouping in the market, age, status and gender. The aim of this study was to increase the knowledge of consumer behavior of digital props within games. The data from the survey was examined to find the factors that define those who purchase aesthetic digital props. Two of the five hypotheses that were put forth were confirmed. The first one being H2: users who know other users who have bought aesthetic digital props are more likely to buy aesthetic digital props ( (1, N = 533) = 49.753, p = < .001), it had a medium effect size (Cramer´s Phi = .306). The other hypothesis was H4: users who follow the game, EVE Online, on social media are more likely to buy aesthetic digital props ( (3, N = 531) = 24.772, p = < .001), which also had a medium effect size (Cramer´s Phi = .216). The results suggest that social factors play a part in the purchase of these digital props. Perhaps as status symbols, to distinguish the player from a certain groups or to belong to a group within the game. Keywords: Digital props, consumer behaviour, mmorpgs, EVE Onlin

Allostatic dysregulation of natural reward processing in prescription opioid misuse: Autonomic and attentional evidence

Chronic pain patients who misuse prescription opioids may suffer from allostatic dysregulation of natural reward processing. Hence, this study examined whether prescription opioid misusers with chronic pain (n = 72) evidenced decreased natural reward responsiveness relative to non-misusers with chronic pain (n = 26). Subjects completed a dot probe task containing pain-related, opioid-related, and natural reward stimuli while attentional bias (AB) scores and heart rate variability (HRV) responses were assessed. Compared to non-misusers, misusers evidenced significantly more attenuated HRV responses to opioid, pain, and natural reward cues presented during the dot probe task. These significant between-groups differences in HRV were largest during attention to natural reward cues, but became non-significant in a sensitivity analysis controlling for opioid dosing. In addition, non-misusers evidenced an AB toward natural reward cues, whereas misusers did not. Findings suggest that opioid misusers exhibit attentional and autonomic deficits during reward processing