887 research outputs found

    Observations of V592 Cas -— an Outflow at Optical Wavelengths

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    We present new red optical spectra of V592 Cas aimed at exploring the properties of the outflow of this system in a spectral region where the underlying white dwarf and the accretion disk do not contribute significantly to the observed absorption components of the Hα and He I line profiles. We use the Hα emission line to study the wind, which appears as pronounced blueshifted P Cygni absorption troughs whose low velocity end contaminates the blue side of the emission line profile. The wind appears to be episodic in nature, with multiple events reaching velocities of 5000 km s^–1 in Hα. Similar (but weaker) wind signatures appear in the He I 5876 Å line but are absent in He I 6678 Å. Our data suggest that during wind episodes the wind is phase dependent and is visible for half of the orbit of the system. Considering that V592 Cas is viewed almost face-on, the symmetry axis of the outflow cannot be orthogonal to the disk and/or the outflow must have some other inherent asymmetry in outflow geometry. A possible origin of the wind is in a disk hotspot, either at the initial impact point of the accretion stream on the disk edge or as a result of disk overflow (similar to SW Sextantis stars). Simultaneous optical photometry during one night of our spectroscopic observations indicate that there is no clear relationship between the optical brightness variations and the strength of the outflow in this system

    Multi-locus phylogeny of dolphins in the subfamily Lissodelphininae: character synergy improves phylogenetic resolution

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    BACKGROUND: Dolphins of the genus Lagenorhynchus are anti-tropically distributed in temperate to cool waters. Phylogenetic analyses of cytochrome b sequences have suggested that the genus is polyphyletic; however, many relationships were poorly resolved. In this study, we present a combined-analysis phylogenetic hypothesis for Lagenorhynchus and members of the subfamily Lissodelphininae, which is derived from two nuclear and two mitochondrial data sets and the addition of 34 individuals representing 9 species. In addition, we characterize with parsimony and Bayesian analyses the phylogenetic utility and interaction of characters with statistical measures, including the utility of highly consistent (non-homoplasious) characters as a conservative measure of phylogenetic robustness. We also explore the effects of removing sources of character conflict on phylogenetic resolution. RESULTS: Overall, our study provides strong support for the monophyly of the subfamily Lissodelphininae and the polyphyly of the genus Lagenorhynchus. In addition, the simultaneous parsimony analysis resolved and/or improved resolution for 12 nodes including: (1) L. albirostris, L. acutus; (2) L. obscurus and L. obliquidens; and (3) L. cruciger and L. australis. In addition, the Bayesian analysis supported the monophyly of the Cephalorhynchus, and resolved ambiguities regarding the relationship of L. australis/L. cruciger to other members of the genus Lagenorhynchus. The frequency of highly consistent characters varied among data partitions, but the rate of evolution was consistent within data partitions. Although the control region was the greatest source of character conflict, removal of this data partition impeded phylogenetic resolution. CONCLUSION: The simultaneous analysis approach produced a more robust phylogenetic hypothesis for Lagenorhynchus than previous studies, thus supporting a phylogenetic approach employing multiple data partitions that vary in overall rate of evolution. Even in cases where there was apparent conflict among characters, our data suggest a synergistic interaction in the simultaneous analysis, and speak against a priori exclusion of data because of potential conflicts, primarily because phylogenetic results can be less robust. For example, the removal of the control region, the putative source of character conflict, produced spurious results with inconsistencies among and within topologies from parsimony and Bayesian analyses

    Emotional Intelligence Training and Professional Salespeople

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    Emotional intelligence (EI) has long been considered a significant success factor, especcially in careers like personal selling that involve considerable social. contact (Goldman, 1995). As a result, a series of studies have investigated the link between EI and sales performance. The results of these studies indicates that EI can positively impact sales performanace. As a result, researchers (Deeter-Schmelz & Sojka, 2003) have called for its integration into sales training programs. However, to this point, no research has established an effective approach to EI training in sales. This study begins to rectify that shortcoming by indentifying best practices in general EI training that can be adapted to meet sales training goals. Guidelines to the development of EI training in sales are also provided

    The Photometric Period and Variability of the Cataclysmic Variable V849 Herculis (PG 1633+115)

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    We report time-resolved photometry of the cataclysmic variable V849 Her, and measure a period of 0.1414 \pm 0.0030 days (3.394 \pm 0.072 hours). We also present photometry taken over several weeks in 2010 and 2011, as well as light curves from 1995 to 2011 by the American Association of Variable Star Observers. The spectra, absolute magnitude derived from infrared magnitudes, and variability all suggest that V849 Her is a nova-like variable. The shallow (0.5-magnitude) low states we observe resemble the erratic low states of the VY Sculptoris stars, although they may recur quasi-periodically over an average cycle of 12.462 \pm 0.074 days.Comment: 18 pages, 9 figures, accepted for publication in New Astronom

    Soliciting Human-in-the-Loop User Feedback for Interactive Machine Learning Reduces User Trust and Impressions of Model Accuracy

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    Mixed-initiative systems allow users to interactively provide feedback to potentially improve system performance. Human feedback can correct model errors and update model parameters to dynamically adapt to changing data. Additionally, many users desire the ability to have a greater level of control and fix perceived flaws in systems they rely on. However, how the ability to provide feedback to autonomous systems influences user trust is a largely unexplored area of research. Our research investigates how the act of providing feedback can affect user understanding of an intelligent system and its accuracy. We present a controlled experiment using a simulated object detection system with image data to study the effects of interactive feedback collection on user impressions. The results show that providing human-in-the-loop feedback lowered both participants' trust in the system and their perception of system accuracy, regardless of whether the system accuracy improved in response to their feedback. These results highlight the importance of considering the effects of allowing end-user feedback on user trust when designing intelligent systems.Comment: Accepted and to appear in the Proceedings of the AAAI Conference on Human Computation and Crowdsourcing (HCOMP) 202

    Gauging the Effect of Buyer vs. Seller Initiation of Customer Value Creation on Buyer Loyalty in Large B2B Sales Relationships

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    This study addresses two central questions: Is it important to determine whether the salesperson or the buyer initiates value creation in large business-to-business (B2B) selling environments? Furthermore, does the mode of initiation – buyer or seller – later influence customer attitudes toward the sales interaction? Value creation is necessary for large B2B sales situations because customized solutions often are required to meet customer needs. This empirical study compares buyer and seller initiators of value creation in B2B dealings and analyzes which actor most positively affects customer perceptions. In a study of 142 senior-level managers at buyer organizations who participated in large-sale deals, we quantitatively analyzed the relationship to identify who initiates value creation, based on the initial Net Promoter Score (NPS). Buyer managers rated seller-initiated value creation higher than buyer-initiated value creation, and seller-initiated value creation had a net positive effect on buyer attitudes and loyalty. The study concludes by offering sales managers practical strategies for enhancing buyer satisfaction, creating positive customer word-of-mouth, and engendering customer loyalty

    Multi-locus phylogeography of the dusky dolphin (Lagenorhynchus obscurus): passive dispersal via the west-wind drift or response to prey species and climate change?

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    <p>Abstract</p> <p>Background</p> <p>The dusky dolphin (<it>Lagenorhynchus obscurus</it>) is distributed along temperate, coastal regions of New Zealand, South Africa, Argentina, and Peru where it feeds on schooling anchovy, sardines, and other small fishes and squid tightly associated with temperate ocean sea surface temperatures. Previous studies have suggested that the dusky dolphin dispersed in the Southern Hemisphere eastward from Peru via a linear, temperate dispersal corridor provided by the circumpolar west-wind drift. With new mitochondrial and nuclear DNA sequence data, we propose an alternative phylogeographic history for the dusky dolphin that was structured by paleoceanographic conditions that repeatedly altered the distribution of its temperate prey species during the Plio-Pleistocene.</p> <p>Results</p> <p>In contrast to the west-wind drift hypothesis, phylogenetic analyses support a Pacific/Indian Ocean origin, with a relatively early and continued isolation of Peru from other regions. Dispersal of the dusky dolphin into the Atlantic is correlated with the history of anchovy populations, including multiple migrations from New Zealand to South Africa. Additionally, the cooling of the Eastern Equatorial Pacific led to the divergence of anchovy populations, which in turn explains the north-south equatorial transgression of <it>L. obliquidens </it>and the subsequent divergence of <it>L. obscurus </it>in the Southern Hemisphere.</p> <p>Conclusion</p> <p>Overall, our study fails to support the west-wind drift hypothesis. Instead, our data indicate that changes in primary productivity and related abundance of prey played a key role in shaping the phylogeography of the dusky dolphin, with periods of ocean change coincident with important events in the history of this temperate dolphin species. Moderate, short-term changes in sea surface temperatures and current systems have a powerful effect on anchovy populations; thus, it is not infeasible that repeated fluctuations in anchovy populations continue to play an important role in the history of coastal dolphin populations.</p

    Identification of Potential Seepage Locations Along the Herbert Hoover Dike, Lake Okeechobee FL., by Electromagnetic Geophysical Method. Prediction and Confirmation.

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    This case history demonstrates the use of electromagnetic (EM) induction methods to examine known seepage locations and then predict future ones along the Herbert Hoover Dike (HHD) in south central Florida. The HHD forms an embankment dam 20 to 30 feet high and 140 miles long surrounding Lake Okeechobee. Approximately 26 miles of embankment was surveyed with EM induction. The objective of the EM survey was to identify active and potential foundation seepage locations and conduits. Areas of greater conductivity were often associated with seepage locations observed during a record high water event in October, 1995. These problems included boils and piping of foundation and embankment materials. One great benefit of this investigation was that large areas of competent dike foundations could be separated from areas containing potential problems requiring additional examination

    Reply to Comment on "Criterion that Determines the Foldability of Proteins"

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    We point out that the correlation between folding times and σ=(Tθ−Tf)/Tθ\sigma = (T_{\theta } - T_{f})/T_{\theta } in protein-like heteropolymer models where TθT_{\theta } and TfT_{f} are the collapse and folding transition temperatures was already established in 1993 before the other presumed equivalent criterion (folding times correlating with TfT_{f} alone) was suggested. We argue that the folding times for these models show no useful correlation with the energy gap even if restricted to the ensemble of compact structures as suggested by Karplus and Shakhnovich (cond-mat/9606037).Comment: 6 pages, Latex, 2 Postscript figures. Plots explicitly showing the lack of correlation between folding time and energy gap are adde
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