Occupational health and the analytical and numerical modeling of airflow patterns in the industrial environment

Possibly the world's first research on breathing problems among snow crab processing workers took place in Newfoundland in the 1970's. Preventing/mitigating these problems is of paramount importance as the snow crab industry is a major contributor to the regional economy in rural Newfoundland and Labrador communities. Crab asthma is caused by overexposure to the dusts, mists, fumes or aerosols that are generated during various processes. During these processes, proteins in the crab may become airborne and can enter the lungs and breathing tubes. A recent study suggests that very low levels of allergen will need to be achieved in crab processing plants to prevent respiratory symptoms from occurring among sensitized workers. Prior to the study described in this report, there had been no air sampling of allergen levels in snow crab processing plants in Newfoundland and Labrador. Air sampling has been carried out in four crab processing plants in Newfoundland and Labrador to identify the problematic areas. Allergen contamination concentrations have been identified and related to specific areas of the processing plants and to the individual processes themselves. -- A variety of ventilation methods have been examined with local exhausting of the workplace comprising the majority of the investigated techniques. Centerline velocity profiles for overhead, slotted, and canopy local exhaust hoods proposed in previous research have been examined. Numerical modeling of the cleaning, sawing, and batch cooling processes was carried out in both an idealistic and realistic plant domain to determine the airflow patterns in and around these individual processes, as well as determining possible capture velocities from imposed velocity profiles. Velocity profiles have been obtained for the space in the vicinity of the hood face rather than just along the centerline. Velocity and pressure contours were also determined to ascertain the degree of contaminant capture. All numerical results for idealistic and realistic plant environments have been investigated, discussed, and presented

The Parallel Persistent Memory Model

We consider a parallel computational model that consists of $P$ processors, each with a fast local ephemeral memory of limited size, and sharing a large persistent memory. The model allows for each processor to fault with bounded probability, and possibly restart. On faulting all processor state and local ephemeral memory are lost, but the persistent memory remains. This model is motivated by upcoming non-volatile memories that are as fast as existing random access memory, are accessible at the granularity of cache lines, and have the capability of surviving power outages. It is further motivated by the observation that in large parallel systems, failure of processors and their caches is not unusual. Within the model we develop a framework for developing locality efficient parallel algorithms that are resilient to failures. There are several challenges, including the need to recover from failures, the desire to do this in an asynchronous setting (i.e., not blocking other processors when one fails), and the need for synchronization primitives that are robust to failures. We describe approaches to solve these challenges based on breaking computations into what we call capsules, which have certain properties, and developing a work-stealing scheduler that functions properly within the context of failures. The scheduler guarantees a time bound of $O(W/P_A + D(P/P_A) \lceil\log_{1/f} W\rceil)$ in expectation, where $W$ and $D$ are the work and depth of the computation (in the absence of failures), $P_A$ is the average number of processors available during the computation, and $f \le 1/2$ is the probability that a capsule fails. Within the model and using the proposed methods, we develop efficient algorithms for parallel sorting and other primitives.Comment: This paper is the full version of a paper at SPAA 2018 with the same nam

Selective attention moderates the relationship between attentional capture by signals of nondrug reward and illicit drug use

BACKGROUND: The current study examined whether cognitive control moderates the association between (non-drug) reward-modulated attentional capture and use of alcohol and other drugs (AOD). METHODS: Participants were 66 university students who completed an assessment including questions about AOD use, a visual search task to measure value-modulated attentional capture, and a goal-directed selective attention task as a measure of cognitive control. RESULTS: The association between the effect of value-modulated attentional capture and illicit drug use was moderated by level of cognitive control. Among participants with lower levels of cognitive control, value-modulated attentional capture was associated with illicit drug use. This was not the case among participants with higher levels of cognitive control, who instead showed a significant association between illicit drug use and self-reported impulsivity, as well as alcohol use. CONCLUSIONS: These results provide support for models that view addictive behaviours as resulting from interaction and competition between automatic and more reflective processes. That is, the mechanisms that ultimately drive addictive behaviour may differ between people low or high in cognitive control. This has important implications for understanding the development and maintenance of substance use disorders and potentially their treatment and prevention

HetFS: A heterogeneous file system for everyone

Storage devices have been getting more and more diverse during the last decade. The advent of SSDs made it painfully clear that rotating devices, such as HDDs or magnetic tapes, were lacking in regards to response time. However, SSDs currently have a limited number of write cycles and a significantly larger price per capacity, which has prevented rotational technologies from begin abandoned. Additionally, Non-Volatile Memories (NVMs) have been lately gaining traction, offering devices that typically outperform NAND-based SSDs but exhibit a full new set of idiosyncrasies. Therefore, in order to appropriately support this diversity, intelligent mechanisms will be needed in the near-future to balance the benefits and drawbacks of each storage technology available to a system. In this paper, we present a first step towards such a mechanism called HetFS, an extension to the ZFS file system that is capable of choosing the storage device a file should be kept in according to preprogrammed filters. We introduce the prototype and show some preliminary results of the effects obtained when placing specific files into different devices.The research leading to these results has received funding from the European Community under the BIGStorage ETN (Project 642963 of the H2020-MSCA-ITN-2014), by the Spanish Ministry of Economy and Competitiveness under the TIN2015-65316 grant and by the Catalan Government under the 2014-SGR- 1051 grant. To learn more about the BigStorage project, please visit http: //bigstorage-project.eu/.Peer ReviewedPostprint (author's final draft

Value-modulated attentional capture in reward and punishment contexts, attentional control, and their relationship with psychopathology

Attentional bias towards rewards has been extensively studied in both healthy and clinical populations. Several studies have shown an association between reward value-modulated attentional capture (VMAC) and greater substance use. However, less is known about the association between these VMAC effects and internalizing symptoms. Moreover, while VMAC effects have also been found in punishment contexts, the association between punishment VMAC and psychopathology has not been studied so far. In the present two-part preregistered study, we adapted a novel VMAC task to also include a punishment context and examined associations with internalizing symptoms and substance use. Our results showed consistent VMAC effects in reward contexts across two separate studies. Attentional capture was stronger for distractors associated with high rewards than for low rewards. We replicated and extended previous findings by showing such VMAC effects in a substantially shorter task that also included alternating punishment blocks. Contrary to our expectations, we found no VMAC effects in punishment contexts and no direct associations between VMAC and symptom measures. Our results speak to the feasibility of assessing VMAC effects using a scalable and short behavioral online task, but the relationship with the development of internalizing and externalizing psychopathology remains uncertain.</p

Value-modulated attentional capture in reward and punishment contexts, attentional control, and their relationship with psychopathology

Attentional bias towards rewards has been extensively studied in both healthy and clinical populations. Several studies have shown an association between reward value-modulated attentional capture (VMAC) and greater substance use. However, less is known about the association between these VMAC effects and internalizing symptoms. Moreover, while VMAC effects have also been found in punishment contexts, the association between punishment VMAC and psychopathology has not been studied so far. In the present two-part preregistered study, we adapted a novel VMAC task to also include a punishment context and examined associations with internalizing symptoms and substance use. Our results showed consistent VMAC effects in reward contexts across two separate studies. Attentional capture was stronger for distractors associated with high rewards than for low rewards. We replicated and extended previous findings by showing such VMAC effects in a substantially shorter task that also included alternating punishment blocks. Contrary to our expectations, we found no VMAC effects in punishment contexts and no direct associations between VMAC and symptom measures. Our results speak to the feasibility of assessing VMAC effects using a scalable and short behavioral online task, but the relationship with the development of internalizing and externalizing psychopathology remains uncertain.</p