735 research outputs found

    Predicting Bird Oiling Events at Oil Sands Tailings Ponds and Assessing the Importance of Alternate Waterbodies for Waterfowl: a Preliminary Assessment

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    Tailings ponds are an integral part of oil sands mining development in northeastern Alberta, but waterfowl and shorebirds often land in these ponds during spring migration where they may become covered with oil. For decades, managers have developed and implemented methods for deterring birds from landing in these ponds, yet no deterrent strategy is fully effective. Therefore, to enhance deterrence strategies, it will be important to understand the environmental conditions that influence bird use of tailings ponds. This study quantified waterfowl flights over, and use of, tailings ponds and compared this use to waterfowl activity at natural waterbodies in the region over a single spring migration period. Results suggest that waterfowl are most likely to land on tailings ponds before lakes have thawed, after which migratory ducks appeared mainly to use natural waterbodies for migratory stopover sites. Very high numbers of waterfowl were observed on one waterbody, Kearl Lake, suggesting that this lake may be of greater importance to spring staging waterfowl than previously thought. A small sample of birds oiled at tailings ponds were examined in relation to spring weather conditions. Logistic regression analysis demonstrated that the probability of birds being oiled tended to increase with precipitation levels. Results of this study suggest that (1) preservation of natural waterbodies may play an important role in minimizing bird use of tailings ponds, and (2) future bird deterrence efforts should especially aim to deter birds during rainy weather conditions when birds may be more likely to become oiled. These results were from a small sample size, are preliminary in nature, and should be interpreted with caution. A concerted and careful effort to collect and thoroughly analyze long-term records of oiled birds may reveal important environmental effects predicting bird oiling events

    Greening crowdfunding campaigns: an investigation of message framing and effective communication strategies for funding success

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    Purpose: Recognising the growing importance of environmental and sustainable activities and the role of communication strategies in soliciting their financing, this work investigates the influence of message framing, green emphasis and quantitative information on the probability of green crowdfunding campaigns' success. Design/methodology/approach: This analysis is based on crowdfunding campaigns published between 2015 and 2020 on the Indiegogo platform in the category “Community projects – Environment”. The study develops an in-depth qualitative content analysis of the projects before performing an empirical examination to determine funding causes. Findings: Communication strategies (message framing, green emphasis and quantitative goals) affect funding success. However, project category moderates the impact of message framing and green emphasis on campaign success. While positive framing increases agri-food campaign success, negative framing is more effective for clean energy and climate preservation projects. Moreover, indication of a quantitative goal and a marked green emphasis in a project's presentation increase campaign success, but a too marked green emphasis is only effective for agri-food projects. Practical implications: Green entrepreneurs and campaign managers must work carefully on their projects' communication, accounting for the type of product proposed, emphasising green components in its description and utilising quantitative information to present future goals. These strategies maximise backers' responses and enable entrepreneurs to obtain funding. The authors’ findings may be extended to other contexts, including the banking sector, to craft effective communication strategies for green financial products. Originality/value: By applying framing theory in a new context (i.e. the online financing of green entrepreneurs), this study identifies new campaign success determinants and provides evidence for the moderating role of project category. Furthermore, the study highlights the need to develop different communication strategies for social and environmental-oriented projects

    Does alexithymia have a mediating effect between impulsivity and emotional-behavioral functioning in adolescents with binge eating disorder?

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    Objective: Binge eating Disorder (BeD) has recently been included in the Dsm-5. like many other eating disorder symptoms, BED is often present in adolescence. No studies have specifically investigated the influence of impulsivity and alexithymia on the emotional-behavioural functioning of adolescents diagnosed with BeD. Method: in this study, we recruited n = 162 adolescents (age range: 14-18) and divided them into two groups: 78 adolescents diagnosed with BeD, according to the Dsm-5 criteria (group A), and 84 healthy controls (group B). participants completed the youth self-report (ysr/11-18), the toronto Alexithymia scale (tAs-20) and the Barratt impulsiveness scale (Bis-11). Results: the results showed that group A had higher scores of alexithymia, impulsivity and maladaptive emotionalbehavioural functioning than Group B. Furthermore, alexithymia had a mediating effect on the relationship between impulsivity and emotional-behavioural functioning. Conclusions: These results allow us to hypothesise that alexithymia is a key variable influencing the emotional and behavioural problems of adolescents affected by BED. Our data confirms the previous studies underlining the association of impulsivity and alexithymia with the diagnosis of BeD in adolescents, and our study contributes to the previous literature, emphasising the central role of alexithymia in the mediating effect between impulsivity and emotional and behavioural problems. these results suggest the importance of promoting prevention and treatment polices focused on alexithymia

    A Stochastic Theory of the Hierarchical Clustering III. The Non-universality and Non-stationarity of the Halo Mass Function

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    In the framework of the stochastic theory for hierarchical clustering, we investigate the time-dependent solutions of the Fokker-Planck equation describing the statistics of dark matter halos, and discuss the typical timescales needed for these to converge toward stationary states, far away enough from initial conditions. Although we show that the stationary solutions can reproduce the outcomes of state-of-the-art NN-body simulations at z0z\approx 0 to a great accuracy, one needs to go beyond to fully account for the cosmic evolution of the simulated halo mass function toward high-redshift. Specifically, we demonstrate that the time-dependent solutions of the Fokker-Planck equation can describe, for reasonable initial conditions, the non-universal evolution of the simulated halo mass functions. Compared to standard theoretical estimates, our stochastic theory predicts a halo number density higher by factor of several toward z10z\gtrsim 10, an outcome which can be helpful in elucidating early and upcoming data from JWST. Finally, we point out the relevance of our approach in designing, interpreting and emulating present and future NN-body experiments.Comment: 14 pages, 5 Figures. Accepted by Ap

    Binding Mechanisms in Visual Perception and Their Link With Neural Oscillations: A Review of Evidence From tACS

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    Neurophysiological studies in humans employing magneto- (MEG) and electro- (EEG) encephalography increasingly suggest that oscillatory rhythmic activity of the brain may be a core mechanism for binding sensory information across space, time, and object features to generate a unified perceptual representation. To distinguish whether oscillatory activity is causally related to binding processes or whether, on the contrary, it is a mere epiphenomenon, one possibility is to employ neuromodulatory techniques such as transcranial alternating current stimulation (tACS). tACS has seen a rising interest due to its ability to modulate brain oscillations in a frequency-dependent manner. In the present review, we critically summarize current tACS evidence for a causal role of oscillatory activity in spatial, temporal, and feature binding in the context of visual perception. For temporal binding, the emerging picture supports a causal link with the power and the frequency of occipital alpha rhythms (8–12 Hz); however, there is no consistent evidence on the causal role of the phase of occipital tACS. For feature binding, the only study available showed a modulation by occipital alpha tACS. The majority of studies that successfully modulated oscillatory activity and behavioral performance in spatial binding targeted parietal areas, with the main rhythms causally linked being the theta (~7 Hz) and beta (~18 Hz) frequency bands. On the other hand, spatio-temporal binding has been directly modulated by parieto-occipital gamma (~40–60 Hz) and alpha (10 Hz) tACS, suggesting a potential role of cross-frequency coupling when binding across space and time. Nonetheless, negative or partial results have also been observed, suggesting methodological limitations that should be addressed in future research. Overall, the emerging picture seems to support a causal role of brain oscillations in binding processes and, consequently, a certain degree of plasticity for shaping binding mechanisms in visual perception, which, if proved to have long lasting effects, can find applications in different clinical populations

    Multi-COBS: A Novel Algorithm for Byte Stuffing at High Throughput

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    Framing methods are used to break a data stream into packets in most digital communications. The use of a reserved symbol to denote the frame boundaries is a popular practice. This end-of-frame (EOF) marker should be removed from the packet content in a reversible manner. Many strategies, such as the bit and byte stuffing processes employed by high-level data link control (HDLC) and Point-to-Point Protocol (PPP), or the Consistent Overhead Byte Stuffing (COBS), have been devised to perform this goal. These bit and byte stuffing algorithms remove the reserved EOF marker from the packet payload and replace it with some extra information that can be used to undo the action later. The amount of data added is called overhead and is a figure-of-merit of such algorithms, together with the encoding and decoding speed. Multi-COBS, a new byte stuffing algorithm, is presented in this paper. Multi-COBS provides concurrent encoding and decoding, resulting in a performance improvement of factor four or eight in common word-based digital architectures while delivering an average and worst-case overhead equivalent to the state-of-the-art. On the reference 28-nanometer field programmable gate array (FPGA) (Artix-7), Multi-COBS achieves a throughput of 6.6 Gbps, instead of 1.7 Gbps of COBS. Thanks to its parallel elaboration capability, Multi-COBS is ideal for digital systems built in programmable logic as well as modern computers

    Numerical and Experimental Validation of Active Vibration Control Logic Performance of a Hybrid Noise Control-Based Brick

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    The limitations of active noise control (ANC) in coping with low frequencies and of passive noise control (PNC) in coping with middle-high frequencies are objects of research that present the potentialities of hybrid noise control (HBC). It aims at combining both of the behaviours by broadening the range of absorbed frequencies. Among the several application fields, the AEC (architecture, engineering, and construction) market can take advantage for those applications in which the noise conditions are caused by sound sources that tune in a broad frequencies range. In this frame, the paper describes the numerical and experimental validation of the active behaviour of an under-development project of a hybrid noise control-based acoustic bricks. The latter intends to embed the potentialities of active vibrational noise control (AVC) and passive destructive interference (PDI) in a unique design of an easy-to-mount, 3D-printed, customisable smart acoustic blocks. Active vibration control, the object of this paper, is provided by a 5-mm thick aluminium circular plate with an attached piezoelectric patch. The vibration of the latter, depending on a specific control law, defines the vibration of the plate itself achieving an abatement of the reflection coefficient. Through mathematical modelling and tests in an impedance tube, the results show that the control logic can reach an average abatement of the reflection coefficient of 82% in the frequency range 144-1007 Hz

    Anomalous Perception of Biological Motion in Autism: A Conceptual Review and Meta-Analysis

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    Despite its popularity, the construct of biological motion (BM) and its putative anomalies in autism spectrum disorder (ASD) are not completely clarified. In this article, we present a meta-analysis investigating the putative anomalies of BM perception in ASD. Through a systematic literature search, we found 30 studies that investigated BM perception in both ASD and typical developing peers by using point-light display stimuli. A general meta-analysis including all these studies showed a moderate deficit of individuals with ASD in BM processing, but also a high heterogeneity. This heterogeneity was explored in different additional meta-analyses where studies were grouped according to levels of complexity of the BM task employed (first-order, direct and instrumental), and according to the manipulation of low-level perceptual features (spatial vs. temporal) of the control stimuli. Results suggest that the most severe deficit in ASD is evident when perception of BM is serving a secondary purpose (e.g., inferring intentionality/action/emotion) and, interestingly, that temporal dynamics of stimuli are an important factor in determining BM processing anomalies in ASD. Our results question the traditional understanding of BM anomalies in ASD as a monolithic deficit and suggest a paradigm shift that deconstructs BM into distinct levels of processing and specific spatio-temporal subcomponents

    Relax-and-fix heuristics applied to a real-world lot-sizing and scheduling problem in the personal care consumer goods industry

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    This paper addresses an integrated lot-sizing and scheduling problem in the industry of consumer goods for personal care, a very competitive market in which the good customer service level and the cost management show up in the competition for the clients. In this research, a complex operational environment composed of unrelated parallel machines with limited production capacity and sequence-dependent setup times and costs is studied. There is also a limited finished-goods storage capacity, a characteristic not found in the literature. Backordering is allowed but it is extremely undesirable. The problem is described through a mixed integer linear programming formulation. Since the problem is NP-hard, relax-and-fix heuristics with hybrid partitioning strategies are investigated. Computational experiments with randomly generated and also with real-world instances are presented. The results show the efficacy and efficiency of the proposed approaches. Compared to current solutions used by the company, the best proposed strategies yield results with substantially lower costs, primarily from the reduction in inventory levels and better allocation of production batches on the machines
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