Illumination matters part IV: blackout and whiteout in flexible ureteroscopy - first report on a phenomenon observed by PEARLS.

PURPOSE: To date, no study has evaluated effects of varying brightness settings on image quality from flexible ureteroscopes submerged in saline. The aim was to evaluate blackout and whiteout occurrences in an in-vitro kidney calyx model. MATERIAL AND METHODS: We evaluated a series of contemporary flexible ureteroscopes including the Storz Flex-Xc and Flex-X2s, Olympus V3 and P7, Pusen 7.5F and 9.2F, as well as OTU WiScope using a 3D-printed enclosed pink in-vitro kidney calyx model submerged in saline. Endoscopic images were captured with ureteroscope tip placed at 5 mm,10 mm and 20 mm distances. The complete range of brightness settings and video capture modes were evaluated for each scope. Distribution of brightness on a grayscale histogram of images was analyzed (scale range 0 to 255). Blackout and whiteout were defined as median histogram ranges from 0 to 35 and 220 to 255, respectively (monitor image too dark or too bright for the human eye, respectively). RESULTS: Blackout occurred with the P7, Pusen 7.5F, 9.2F and WiScope at all distances, and V3 at 20 mm - with lowest brightness settings. Whiteout occurred with Flex-X2s, V3 and P7 at 5 mm and 10 mm, as well as with V3 and P7 at 20 mm - mostly with highest brightness settings. The Flex-Xc had neither blackout nor whiteout at all settings and distances. CONCLUSION: Blackout or whiteout of images is an undesirable property that was found for several scopes, possibly impacting diagnostic and therapeutic purposes during ureteroscopy. These observations form a guide to impact a urologist's choice of instruments and settings.

Effects of hyperventilation on oxygenation, apnea breaking points, diving response, and spleen contraction during serial static apneas.

PURPOSE: Hyperventilation is considered a major risk factor for hypoxic blackout during breath-hold diving, as it delays the apnea breaking point. However, little is known about how it affects oxygenation, the diving response, and spleen contraction during serial breath-holding. METHODS: 18 volunteers with little or no experience in freediving performed two series of 5 apneas with cold facial immersion to maximal duration at 2-min intervals. In one series, apnea was preceded by normal breathing and in the other by 15 s of hyperventilation. End-tidal oxygen and end-tidal carbon dioxide were measured before and after every apnea, and peripheral oxygen saturation, heart rate, breathing movements, and skin blood flow were measured continuously. Spleen dimensions were measured every 15 s. RESULTS: Apnea duration was longer after hyperventilation (133 vs 111 s). Hyperventilation reduced pre-apnea end-tidal CO2 (17.4 vs 29.0 mmHg) and post-apnea end-tidal CO2 (38.5 vs 40.3 mmHg), and delayed onset of involuntary breathing movements (112 vs 89 s). End-tidal O2 after apnea was lower in the hyperventilation trial (83.4 vs 89.4 mmHg) and so was the peripheral oxygen saturation nadir after apnea (90.6 vs 93.6%). During hyperventilation, the nadir peripheral oxygen saturation was lower in the last apnea than in the first (94.0% vs 86.7%). There were no differences in diving response or spleen volume reduction between conditions or across series. CONCLUSIONS: Serial apneas  revealed a previously undescribed aspect of hyperventilation; a progressively increased desaturation across the series, not observed after normal breathing and could heighten the risk of a blackout.

Unlocking the depths: multiple factors contribute to risk for hypoxic blackout during deep freediving.

PURPOSE: To examine the effect of freediving depth on risk for hypoxic blackout by recording arterial oxygen saturation (SpO2) and heart rate (HR) during deep and shallow dives in the sea. METHODS: Fourteen competitive freedivers conducted open-water training dives wearing a water-/pressure proof pulse oximeter continuously recording HR and SpO2. Dives were divided into deep (> 35 m) and shallow (10-25 m) post-hoc and data from one deep and one shallow dive from 10 divers were compared. RESULTS: Mean ± SD depth was 53 ± 14 m for deep and 17 ± 4 m for shallow dives. Respective dive durations (120 ± 18 s and 116 ± 43 s) did not differ. Deep dives resulted in lower minimum SpO2 (58 ± 17%) compared with shallow dives (74 ± 17%; P = 0.029). Overall diving HR was 7 bpm higher in deep dives (P = 0.002) although minimum HR was similar in both types of dives (39 bpm). Three divers desaturated early at depth, of which two exhibited severe hypoxia (SpO2 ≤ 65%) upon resurfacing. Additionally, four divers developed severe hypoxia after dives. CONCLUSIONS: Despite similar dive durations, oxygen desaturation was greater during deep dives, confirming increased risk of hypoxic blackout with increased depth. In addition to the rapid drop in alveolar pressure and oxygen uptake during ascent, several other risk factors associated with deep freediving were identified, including higher swimming effort and oxygen consumption, a compromised diving response, an autonomic conflict possibly causing arrhythmias, and compromised oxygen uptake at depth by lung compression possibly leading to atelectasis or pulmonary edema in some individuals. Individuals with elevated risk could likely be identified using wearable technology.

The use of dive computers in forensic investigations of fatal breath-hold diving accidents: a case study.

Freediving is a type of diving in which divers rely solely on how long they can hold their breath underwater during their dive, which is why it can also be referred to as 'breath-hold diving'. Unlike scuba (self-contained underwater breathing apparatus) diving, individuals do not require training or licencing to perform freediving and may not be aware of the risks of this activity. This paper presents a case in which coastguards retrieved a free diver's lifeless body from the seafloor. In most cases such as this, the deceased individual's cause of death would be ruled as drowning. With the deceased diver's dive computer, we concluded that a shallow water blackout caused him to drown. Data from the dive computer were extracted, graphed, and analysed to explain how a skilled swimmer and diver drowned on one of his seemingly ordinary diving trips. The dive computer can be the sole witness to a fatal dive event and provide invaluable information to forensic scientists since the diver is almost always alone. To our knowledge of the available literature, dive computers have been used in scuba diving fatality investigations; however, we believe that they have not been used in death investigations of breath-hold divers. Deficient or hasty conclusions are often based solely on autopsy findings without data collected by diving technicians and investigators. It is crucial to wait to draw conclusions until all possible dive information has been gathered and studied. This study discusses the deficiency in presenting a reasonable idea to the grieving family and friends of how their beloved relative could have drowned even though he was known to be a fit and skilled diver and avid swimmer.

Rate of alcohol-induced blackout experience and its negative consequences among Korean university students.

An alcohol-induced blackout suggested to be related to a rapid increase in blood alcohol concentration and it is closely related to long-term memory creation. Blackout has been experienced by 35% of the general population and over 50% of university student population. In addition, it has been shown that blackout could be a precursor of injury risk. However, the rate of blackout and blackout related negative consequences in Korean university students have rarely been studied. Therefore, the objective of this study was to determine the blackout experience rate and its negative consequences among students from four universities in Korea. A survey was conducted among university students located in Pusan, Korea in 2013. Demographic and blackout related information were collected through self-report questionnaire, including blackout experience, age of first blackout, and negative consequences of blackout. Descriptive statistical analysis was performed for collected data. Of a total of 470 subjects (Male = 217, Female = 253) surveyed, 190 (40.4%) subjects had experienced a blackout at some points in their lives. The majority (86.3%) of them experienced the first blackout between 20-25 years old. Among those who had experienced a blackout, 57.0% reported that they could not remember how they went home at the end of the night, 8.1%, 7.6%, 3.1%, and 2.2% reported that they had bodily injuries, argument, physical or personal fight, and sexual-related incidences, respectively. This study shows that many Korean university students have experienced blackouts and related negative events. These results suggest that more systematic drinking control strategy is required for Korean university students.

A mixed-methods approach to improve the measurement of alcohol-induced blackouts: ABOM-2.

BACKGROUND: Alcohol-induced blackouts describe memory loss resulting from alcohol consumption. Approximately half of college students report experiencing a blackout in their lifetime. Blackouts are associated with an increased risk for negative consequences, including serious injury. Research has documented two types of blackouts, en bloc (EB) and fragmentary (FB). However, research is limited by the lack of a validated measure that differentiates between these two forms of blackout. This study used a mixed-methods approach to improve the assessment of FB and EB among young adults. Specifically, we sought to improve the existing Alcohol-Induced Blackout Measure (ABOM), which was derived from a relatively small pool of items that did not distinguish FB from EB. METHODS: Study 1 used three rounds of cognitive interviewing with U.S. college students (N = 31) to refine existing assessment items. Nineteen refined blackout items were retained for Study 2. Study 2 used face validity, factor analysis, item response theory, and external validation analyses to test the two-factor blackout model among U.S. heavy-drinking college students (N = 474) and to develop and validate a new blackout measure (ABOM-2). RESULTS: Iterative factor analyses demonstrated that the items were well represented by correlated EB and FB factors, consistent with our hypothesis. External validation analyses demonstrated convergent and discriminant validity. These analyses also provided preliminary evidence for the two factors having differential predictive validity (e.g., FB correlated with enhancement drinking motives, while EB correlated with coping and conformity motives). CONCLUSIONS: The Alcohol-Induced Blackout Measure-2 (ABOM-2) improves the measurement of blackout experiences among college students. Its use could facilitate the examination of EB and FB as differential predictors of alcohol-related outcomes in future studies.

Are memories of sexual trauma fragmented?

Alarmingly high rates of sexual assault on campus have motivated American colleges and universities to take steps to address this serious problem. Yet university administrators have often felt ill-equipped to assess allegations of sexual assault. Unsurprisingly, they have sought the expertise of psychologists who can educate administrative staff about the complexities of traumatic memory. Dr. Rebecca Campbell is among the most influential figures teaching university administrators about sexual trauma and memory. The purpose of this article is to review research pertinent to her views on fragmentation of traumatic memories, and the possible roles of tonic immobility and alcohol consumption on how survivors of sexual assault recall their experience.

Decision Support System for Emergencies in Microgrids.

The usual operation of a microgrid (MG) may often be challenged by emergencies related to extreme weather conditions and technical issues. As a result, the operator often needs to adapt the MG's management by either: (i) excluding disconnected components, (ii) switching to islanded mode or (iii) performing a black start, which is required in case of a blackout, followed by either direct reconnection to the main grid or islanded operation. The purpose of this paper is to present an optimal Decision Support System (DSS) that assists the MG's operator in all the main possible sorts of emergencies, thus providing an inclusive solution. The objective of the optimizer, developed in Pyomo, is to maximize the autonomy of the MG, prioritizing its renewable production. Therefore, the DSS is in line with the purpose of the ongoing energy transition. Furthermore, it is capable of taking into account multiple sorts of Distributed Energy Resources (DER), including Renewable Energy Sources (RES), Battery Energy Storage Systems (BESS)-which can only be charged with renewable energy-and local, fuel-based generators. The proposed DSS is applied in a number of emergencies considering grid-forming and grid-following mode, in order to highlight its effectiveness and is verified with the use of PowerFactory, DIgSILENT.

Issues with Modeling a Tunnel Communication Channel through a Plasma Sheath.

We consider two of the most relevant problems that arise when modeling the properties of a tunnel radio communication channel through a plasma layer. First, we studied the case of the oblique incidence of electromagnetic waves on a layer of ionized gas for two wave polarizations. The resonator parameters that provide signal reception at a wide solid angle were found. We also took into account the unavoidable presence of a protective layer between the plasma and the resonator, as well as the conducting elements of the antenna system in the dielectric itself. This provides the first complete simulation for a tunnel communication channel. Noise immunity and communication range studies were conducted for a prospective spacecraft radio line.

Effects of alcohol sensitivity on alcohol-induced blackouts and passing out: An examination of the alcohol sensitivity questionnaire among underage drinkers.

BACKGROUND: The role of alcohol sensitivity in the experience of blacking out and passing out has not been well established. Here, we examined the relation between individual differences in alcohol sensitivity (i.e., numbers of drinks required to experience various effects of alcohol) and reports of blacking out and passing out in the past year. METHODS: Participants (925 healthy, underage college student drinkers) completed the Alcohol Sensitivity Questionnaire (ASQ) and reported on their past year blacking out and passing out experiences. RESULTS: The fit of the ASQ's 2-factor structure was fair (CFI = 0.90, RMSEA = 0.09) in this sample of underage drinkers. In unadjusted models, higher ASQ scores (i.e., requiring more drinks to experience effects, indicating lower alcohol sensitivity) were associated with experiencing more blackouts (IRR = 1.68 [1.31-2.15]) and passing out (IRR = 2.25 [1.59-3.18]) in the past year. After controlling for typical consumption, however, higher ASQ scores were associated with fewer past-year blackouts (IRR = 0.76 [0.60-0.98]). Total ASQ scores moderated the relationship between typical alcohol consumption and blackout occurrence (interaction IRR = 0.96 [0.93-0.98]), but not passing out occurrence (interaction IRR = 0.95 [0.89-1.01]), with the quantity of alcohol consumed more strongly associated with blackout occurrence among higher-sensitivity than lower-sensitivity drinkers. CONCLUSIONS: These findings are consistent with prior work suggesting that low sensitivity may act as a paradoxical risk factor for certain heavy drinking effects, contributing to higher levels of alcohol consumption and more frequent negative consequences while also conferring protection (relative to high-sensitivity peers) at a given level of alcohol exposure.

Persistent attention-deficit/hyperactivity disorder predicts socially oriented, but not physical/physiologically oriented, alcohol problems in early adulthood.

BACKGROUND: Although individuals with histories of childhood attention-deficit/hyperactivity disorder (ADHD) report more alcohol-related problems in adulthood than those without ADHD, it is unknown whether there are group differences in certain types of alcohol problems. We tested whether the nature of alcohol problems differed for individuals with and without childhood ADHD, as well as adulthood-persistent ADHD, to facilitate a personalized medicine approach for alcohol problems in this high-risk group. METHODS: Data were drawn from a prospective, observational study. Children diagnosed with ADHD and demographically similar individuals without childhood ADHD were followed prospectively through young adulthood (N = 453; 87.6% male). ADHD symptom persistence was assessed using self-reports and parent reports. Alcohol problems and heavy drinking were assessed repeatedly from 18-30 years old to construct lifetime measures. RESULTS: Full-sample confirmatory factor analyses identified 5 alcohol problem "types:" interpersonal problems/risky behaviors, occupational/academic impairment, impaired control/treatment seeking, tolerance/withdrawal, and drinking to blackout. Latent class analyses of items within each type yielded the best fit for 3-class solutions for all sets of items except blackout drinking, for which 2 classes emerged. Children with ADHD were more likely than those without ADHD to belong to high-risk latent classes for interpersonal problems/risky behaviors, occupational/academic problems, and impaired control (the high-risk class that indexed treatment-seeking behavior). These effects were driven by individuals whose ADHD symptoms persisted into adulthood. Few group differences emerged for tolerance/withdrawal and blackout drinking, except that individuals with only childhood ADHD (no persistence) were more likely to belong to the low-risk groups than those with adulthood-persistent ADHD and without ADHD. CONCLUSIONS: Individuals with ADHD histories whose symptoms persist into adulthood may be more likely to experience socially oriented alcohol problems and impaired control/treatment seeking than individuals without an ADHD history and those with childhood ADHD only. Tailored alcohol prevention and treatment programs may benefit this high-risk population.

Compound Climate and Infrastructure Events: How Electrical Grid Failure Alters Heat Wave Risk.

The potential for critical infrastructure failures during extreme weather events is rising. Major electrical grid failure or "blackout" events in the United States, those with a duration of at least 1 h and impacting 50,000 or more utility customers, increased by more than 60% over the most recent 5 year reporting period. When such blackout events coincide in time with heat wave conditions, population exposures to extreme heat both outside and within buildings can reach dangerously high levels as mechanical air conditioning systems become inoperable. Here, we combine the Weather Research and Forecasting regional climate model with an advanced building energy model to simulate building-interior temperatures in response to concurrent heat wave and blackout conditions for more than 2.8 million residents across Atlanta, Georgia; Detroit, Michigan; and Phoenix, Arizona. Study results find simulated compound heat wave and grid failure events of recent intensity and duration to expose between 68 and 100% of the urban population to an elevated risk of heat exhaustion and/or heat stroke.

"I Still Don't Know What Happened, Complete Blackout": a Content Analysis of Tweets Referencing Alcohol-Induced Amnesia.

OBJECTIVE: We qualitatively examined the content of alcohol-related blackouts posts ("Tweets") on Twitter, focusing on reflections post-drinking that involved clear references to memory loss. METHODS: We examined publically available Tweets that referenced blackouts after an alcohol consumption event (n = 3,574). RESULTS: Twitter represents a relatively unfiltered glimpse at reflections on alcohol-induced amnesia. As hypothesized, most tweets referencing blackouts did not clearly describe amnesia. In the Tweets that clearly reference amnesia, we identified several themes. Tweeters referenced an 'AlterEgo' who was responsible for all the intoxicated behaviors that were inconsistent with the Tweeter's personality. Additionally, the Tweets discussed ways in which the drinker recovered memories (e.g. from friends, from social media), other events that occurred during the amnesia (e.g. loss of items, help from friends, sexual experiences), and regret about having lost memories. Some Tweeters requested assistance from their followers to reconstruct their drinking event. Tweets have the potential to set norms about acceptable behaviors or scripts following a blackout. CONCLUSIONS: Since most blackout Tweets are ambiguous with regards to alcohol-induced amnesia, these Tweets might be leading people to believe that blackouts are passing out or just periods of heavy intoxication. In addition, themes from these Tweets can inform future interventions by using the cognitions surrounding this high-risk behavior.

Blackout of my nights: Contentless, timeless and selfless report from the night in patients with central hypersomnias.

At the extreme spectrum of consciousness during sleep, some patients with rare hypersomnias reported experiencing a specific night 'blackout' when sleeping, i.e., an absence of experiences or recall of them from sleep onset to offset. Thus, we explored through questionnaires the conscious experiences (dreaming experience, mind, self) during the night in 133 patients with idiopathic hypersomnia, 108 patients with narcolepsy, and 128 healthy controls. The night blackout was more frequent in idiopathic hypersomnia than in narcolepsy and control groups. Patients with idiopathic hypersomnia and frequent night amnesia had lower dream recall frequencies, and felt more often sleep as deep and mind as blank during the night. They had a higher proportion of slow wave sleep on their (retrospectively collected) sleep recordings than those without night blackout. This night blackout provides a new model for studying loss of consciousness during sleep, here as a contentless, selfless and timeless feeling upon awakening.

"Can't Wait to Blackout Tonight": An Analysis of the Motives to Drink to Blackout Expressed on Twitter.

BACKGROUND: Alcohol-related blackouts are associated with a range of negative consequences and are common among social drinkers. Discussing alcohol use on social networking platforms (e.g., Twitter) is common and related to higher alcohol consumption levels. Due to the widespread nature of alcohol-related social networking posts and alcohol-related blackouts, we examined the content of alcohol-related blackouts posts/"Tweets" on Twitter, with a focus on intentions to blackout and specific motivations for blacking out. METHODS: A set of Tweets containing "blackout," "blackout," "blacking out," "blacked out," or "blacks out" were collected from April 26, 2018, and April 29, 2018. Using NVivo software, we coded all preblackout Tweets (i.e., before the blackout experience) for intentions and motives to blackout. RESULTS: Most Tweets that we collected expressed an intention to blackout and these intentions ranged in strength (i.e., will blackout vs. might blackout). With respect to specific motives for blacking out, celebration motives were identified. For example, Tweets addressed blacking out to celebrate one's birthday, someone else's birthday, a school or work accomplishment, a sports win, during a vacation, or a holiday. Another endorsed motive for blacking out was loss or coping motives. For example, the Tweets commented on blacking out to deal with stress or a bad day. CONCLUSION: Our findings suggest that Twitter users express intentions to blackout due to celebration or coping reasons. Given the consequences associated with blackout drinking, future research should consider the link between blackout intentions, blackout motives, and alcohol-related harm.

Genetic Epidemiology of Liability for Alcohol-Induced Blacking and Passing Out.

BACKGROUND: Individuals differ in their sensitivity to alcohol's physiological effects, including blacking and passing out. Blackouts are periods of impaired memory formation when an individual engages in activities they later cannot recall, while passing out results in loss of consciousness. METHODS: The sample consisted of 3,292 adult twins from the Australian Twin Registry. Univariate twin analyses were conducted to examine the contributions of genetic and environmental influences to blacking and passing out occurrence and susceptibility (accounting for frequency of intoxication). Evidence for shared etiology of susceptibility to blacking and passing out was examined using bivariate twin analyses. RESULTS: Although blacking and passing out were strongly associated (odds ratio (OR) = 4.45, 95% confidence interval (CI): [3.85, 5.14]), the genetic epidemiology was quite different. Genetic (43%) and nonshared environmental (57%) influences contributed to liability for blackout occurrence. For passing out occurrence, there was evidence of sex differences. Among men, genetic (32%) and nonshared environmental (68%) influences contributed, whereas among women, there were shared (29%) and nonshared environmental (72%) influences. After accounting for frequency of intoxication, genetic influences on blackout susceptibility remained significant; in contrast, only nonshared environmental influences were significant for passing out susceptibility. There was evidence for overlapping genetic and nonshared environmental factors influencing susceptibility to blacking and passing out among men; among women, there were overlapping nonshared environmental influences. CONCLUSIONS: Blacking and passing out are 2 common sedative-like effects of heavy drinking, and people differ considerably in their susceptibility to these effects. This study suggests that differences in blackout susceptibility can be explained by genetic factors in both men and women, while differences in susceptibility to pass out after consuming alcohol may be attributable to environmental influences, particularly among women. These environmental factors may include changing social and cultural norms about alcohol use, drinking context, and the type(s) of alcohol consumed.

Estrogen Modulates Ethanol-Induced Memory Deficit in Postpubertal Adolescent Rats.

BACKGROUND: Our laboratory and others have reported that ethanol (EtOH) impairs hippocampus-associated memory formation in prepubertal adolescent rats. Acute alcohol exposure in humans produces a syndrome of memory loss ("blackouts") that is similar to impairments caused by hippocampal damage. The ability to form new long-term explicit memories is affected, but not short-term memory storage or recall of information from long-term storage. Alcohol-induced memory impairment, similar to teenage alcohol blackouts, has been shown in prepubertal adolescent rodents. In the present study, EtOH's effect on contextual fear memory was examined in postpubertal rats. METHODS: In Experiment 1, intact male and female postpubertal rats were treated with an acute intraperitoneal injection of EtOH or vehicle. Thirty minutes later, rats were trained in the fear conditioning paradigm, and 24 hours after training, all rats were tested for contextual fear conditioning. In Experiment 2, groups of intact postpubertal female rats were treated with a single injection of EtOH, or vehicle, during different phases of the estrus cycle and tested for fear conditioning. In Experiment 3, groups of postpubertal female rats were ovariectomized (OVX) and were given hormonal supplementation (estrogen with or without progesterone) and tested for EtOH-induced memory formation. Additional controls included sham-operated, oil-treated postpubertal female rats. In Experiment 4, intact postpubertal male rats were administered exogenous estrogen alone or together with progesterone and tested for EtOH-induced contextual memory formation. RESULTS: Following an acute EtOH exposure, intact postpubertal female rats exhibited significant impairments in contextual fear conditioning. But acute EtOH had little effect on contextual fear conditioning in intact postpubertal males. EtOH impaired memory formation during all phases of the estrus cycle except during estrus phase when blood levels of estrogen are low. Ovariectomized rats did not show any EtOH-induced impairment in contextual freezing compared to vehicle-treated ovariectomized rats. In female rats, bilateral ovariectomy eliminated EtOH-induced memory deficit and estrogen replacement reintroduced EtOH-induced memory impairment. Although postpubertal male rats were insensitive to EtOH's effect on contextual fear conditioning, but when treated with exogenous estrogen, they performed poorly in the contextual memory task. CONCLUSIONS: Together, these data suggest that the female gonadal hormone estrogen is an important modulator of EtOH-induced cognitive behavior in postpubertal female and male rats, and that it may play an important role in teenage alcohol blackout.

Efficient Location Service for a Mobile Sink in Solar-Powered Wireless Sensor Networks.

By utilizing mobile sinks in wireless sensor networks (WSNs), WSNs can be deployed in more challenging environments that cannot connect with the Internet, such as those that are isolated or dangerous, and can also achieve a balanced energy consumption among sensors which leads to prolonging the network lifetime. However, an additional overhead is required to check the current location of the sink in order for a node to transmit data to the mobile sink, and the size of the overhead is proportional to that of the network. Meanwhile, WSNs composed of solar-powered nodes have recently been actively studied for the perpetual operation of a network. This study addresses both of these research topics simultaneously, and proposes a method to support an efficient location service for a mobile sink utilizing the surplus energy of a solar-powered WSN. In this scheme, nodes that have a sufficient energy budget can constitute rings, and the nodes belonging to these rings (which are called ring nodes) maintain up-to-date location information on the mobile sink node and serve this information to the other sensor nodes. Because each ring node only uses surplus energy to serve location information, this does not affect the performance of a node's general operations (e.g., sensing, processing, and data delivery). Moreover, because multiple rings can exist simultaneously in the proposed scheme, the overhead for acquiring the position information of the sink can be significantly reduced, and also hardly increases even if the network size becomes larger.

Distinctions in Alcohol-Induced Memory Impairment: A Mixed Methods Study of En Bloc Versus Fragmentary Blackouts.

BACKGROUND: Blackouts-or memory loss for all or part of a drinking event-are reliable predictors of alcohol-related consequences. Studies suggest a distinction between en bloc (complete memory loss) and fragmentary (off-and-on memory loss) blackouts; however, research has not consistently differentiated between these 2 forms of blackout. This study aimed to validate the distinction between en bloc and fragmentary blackouts among young adults. METHODS: Data were collected using qualitative (Study 1) and quantitative (Study 2) research methods. Participants in both studies were college students with a history of alcohol-induced memory impairment. They were recruited using community advertisement (Study 1, N = 50, 56% female) and Qualtrics survey panels (Study 2, N = 350, 56% female). Study 1 participants engaged in 8 focus groups. Discussions were audio-recorded, transcribed verbatim, and coded using applied thematic analysis. Findings guided assessment of en bloc and fragmentary blackout in Study 2. In Study 2, a separate sample of participants completed an online survey assessing drinking behavior, alcohol-induced memory impairment, and theoretical correlates of en bloc and fragmentary blackouts. RESULTS: Study 1 participants differentiated between en bloc and fragmentary blackouts (which they referred to as "blackouts" and "brownouts," respectively) based on duration and extent of memory loss. They indicated that blackouts occur along a continuum, with en bloc "blackouts" at the extreme. They also stated that the term "blackout drinking" does not always imply memory loss. Study 2 participants reported higher rates of "brownouts" (81%) than "blackouts" (54%). They reported less negative outcome expectancies and attitudes, greater personal approval, higher prevalence estimates, lower self-efficacy, and stronger intentions for "brownouts" than "blackouts" (p < 0.001). Women perceived "blackouts/brownouts" as more prevalent than men and reported lower intentions to experience "blackouts" (p < 0.005). CONCLUSIONS: Young adults are more permissive of fragmentary than en bloc blackout. En bloc blackouts may be a target for future interventions.

Blackouts as a Moderator of Young Adult Veteran Response to Personalized Normative Feedback for Heavy Drinking.

BACKGROUND: Blackouts-or periods of alcohol-induced amnesia for all or part of a drinking event-have been identified as independent predictors of alcohol-related harm that may be used to identify individuals who would benefit from intervention. However, little is known about the prevalence and impact of blackouts among Veterans. This study examined blackouts as a moderator of young adult veteran response to a brief, online personalized normative feedback (PNF) intervention for heavy drinking. METHODS: Veterans scoring ≥3/4 (women/men) on the Alcohol Use Disorders Identification Test completed a baseline and 1-month assessment as part of a larger intervention trial (N = 571; 83% male; age M = 28.9, SD = 3.3). Participants were randomized to alcohol PNF (n = 285) or a video game attention control (n = 286). Hierarchical regression was used to examine the interaction between intervention condition and blackouts on alcohol-related outcomes at 1-month follow-up. RESULTS: At baseline, 26% of participants reported loss of memory for drinking events in the past 30 days. The interaction between condition and blackouts was significant, such that PNF participants who had experienced blackouts at baseline reported greater decreases in drinking quantity at 1 month than those who had not, and only PNF participants who had experienced baseline blackouts reported a decrease in alcohol problems at follow-up. CONCLUSIONS: PNF appears to be particularly effective for individuals who have experienced alcohol-induced blackout, perhaps because blackouts prime them for feedback on their alcohol use. While other negative consequences may also prime individuals for behavior change, blackouts are posited as a particularly useful screening tool because they are prevalent among young adults, have a strong association with alcohol-related harm, and are assessed in widely used clinical measures.