Statistical Arbitrage Mining for Display Advertising

We study and formulate arbitrage in display advertising. Real-Time Bidding (RTB) mimics stock spot exchanges and utilises computers to algorithmically buy display ads per impression via a real-time auction. Despite the new automation, the ad markets are still informationally inefficient due to the heavily fragmented marketplaces. Two display impressions with similar or identical effectiveness (e.g., measured by conversion or click-through rates for a targeted audience) may sell for quite different prices at different market segments or pricing schemes. In this paper, we propose a novel data mining paradigm called Statistical Arbitrage Mining (SAM) focusing on mining and exploiting price discrepancies between two pricing schemes. In essence, our SAMer is a meta-bidder that hedges advertisers' risk between CPA (cost per action)-based campaigns and CPM (cost per mille impressions)-based ad inventories; it statistically assesses the potential profit and cost for an incoming CPM bid request against a portfolio of CPA campaigns based on the estimated conversion rate, bid landscape and other statistics learned from historical data. In SAM, (i) functional optimisation is utilised to seek for optimal bidding to maximise the expected arbitrage net profit, and (ii) a portfolio-based risk management solution is leveraged to reallocate bid volume and budget across the set of campaigns to make a risk and return trade-off. We propose to jointly optimise both components in an EM fashion with high efficiency to help the meta-bidder successfully catch the transient statistical arbitrage opportunities in RTB. Both the offline experiments on a real-world large-scale dataset and online A/B tests on a commercial platform demonstrate the effectiveness of our proposed solution in exploiting arbitrage in various model settings and market environments.Comment: In the proceedings of the 21st ACM SIGKDD international conference on Knowledge discovery and data mining (KDD 2015

Sports Rehabilitation and Interprofessional Collaboration

Background: The demand for interprofessional collaboration continues to grow due to changing priorities of the health care system.  The benefits of interprofessional collaboration are well documented; however, the methods of collaboration are often unclear and often difficult to put into practice.  While there is a growing number of studies on the impact of interprofessional collaboration in settings such as inpatient, intensive care units, and acute care, there are limited documented cases regarding the interprofessional management of a physical therapy patient in the outpatient orthopedic private practice setting.   Purpose: The purpose of this paper is to describe the reflections of a physical therapist and an athletic trainer in their experience with interprofessional collaboration, describe the barriers they have experienced that make interprofessional collaboration challenging, and to offer solutions to these barriers.  The barriers discussed in the paper include limited knowledge of and respect for other professionals’ skill set, high-productivity work environments, medical hierarchy, overlapping bodies of knowledge, discrepancy between professional reasoning, territorial behavior, and ineffective communication.  Discussion: It appears that contextual factors, such as community in which the professionals practice, the healthcare setting, and the practice environment, have a far less important impact to successful collaboration than the professionals’ attitudes and investment in the collaborative efforts.  Conclusion: Collaboration between a PT and an AT can lead to power struggles and suboptimal patient care if these barriers are not overcome and collaboration may be necessary to provide the highest quality of patient care

Nebraska Farm Real Estate Market Highlights 2012-2013

This report represents the 35th annual edition of the Nebraska Farm Real Estate Market Developments series. It has continued to provide an important informational role regarding agricultural land market dynamics for the many stakeholders. As stated in the introduction of the first annual report: “The dynamics of the farm real estate market, particularly in recent years, suggests that accurate and complete information concerning this market is of great importance. From the standpoint of the public interest as well as that of individual participants, all land market decisions should be based upon a sound understanding of the current market situation.” 1 In today’s market, where market transactions exceeding a million dollars are the norm, objective market information and analysis is more critical than ever. The annual February 1st University of Nebraska-Lincoln Nebraska Farm Real Estate survey provides the foundation for that effort. This year, the February 2013 survey of over 100 expert-panel reporters from across the state provided current information and insight regarding the agricultural land market conditions in their areas. The panel members have been selected on the basis of being closely affiliated with agricultural land markets as certified agricultural appraisers, professional farm managers, agricultural lenders, etc. Moreover, the vast majority of panelists have reported annually for a number of years; which provides valuable historical consistency and context to the information provided. Based on their knowledge of market activity, reporters provide point-in-time estimates of current agricultural land values and cash rental rates for a variety of land types and classes. Comparing these current measures against previous year’s results provides important trend analysis over time. The historical UNL data series for Nebraska agricultural land values going back to 1978; the agricultural cash rental rate series back to 1981; and the USDA historical all-land value series are included in the appendix to this report. In addition to the point-in-time estimates, panel reporters provide details regarding actual sales transactions which have occurred over the previous 12 months. This year, our panel provided information on 520 sales that were considered representative of the recent agricultural land market. This gives important insight into the characteristics of recent sales as well as benchmark indicators for studying trends over time. Because the state is quite diverse in land resource characteristics and agricultural patterns, most of the market information is provided down to sub-state levels which are the Nebraska Agricultural Statistics Districts (See Figure 1). This provides greater geographically-appropriate detail that is not available from other data sources, such as quarterly value estimates from the Kansas City Federal Reserve and the Economic Research Service-USDA annual Farm Value and Cash Rent series for the state as a whole. But this is not to say that even sub-state levels of values and cash rents appropriately reflect the conditions of any local market in that geographic area. In fact, local differences in values and rents can be extreme. So, the information and analysis to follow here is a more realistic measure of general patterns and trends. Should one need information down to a specific parcel, we strongly recommend they seek out the services of a certified agricultural appraiser and/or a professional farm management firm

Using expletives to enhance therapeutic outcomes: A case report

# Background Swearing deserves attention in the physical therapy setting due to its potential positive effects on pain, physical performance, and therapeutic alliance. The purpose of this case report is to describe the strategic use of swearing in the clinical setting. # Case Presentation A 44-year-old female completed an episode of physical therapy after undergoing patellofemoral arthroplasty. Swearing was formally included into the plan of care, and the patient swore out loud during the most challenging and painful interventions. # Results The patient reported that repeating a swear word was funny, distracted the patient, and made the patient feel more confident. The patient and physical therapist self-reported a strong therapeutic alliance. # Conclusion There is evidence repeating a swear word out loud can strengthen the therapeutic alliance, improve physical performance, and decrease pain. This is, to our knowledge, the first report of a patient swearing during an episode of physical therapy care

A Model of Vertical Oligopolistic Competition

This paper develops a model of successive oligopolies with endogenous market entry, allowing for varying degrees of product differentiation and entry costs in both markets. Our analysis shows that the downstream conditions dominate the overall profitability of the two-tier structure while the upstream conditions mainly affect the distribution of profits. We compare the welfare effects of upstream versus downstream deregulation policies and show that the impact of deregulation may be overvalued when ignoring feedback effects from the other market. Furthermore, we analyze how different forms of vertical restraints influence the endogenous market structure and show when they are welfare enhancing

Shallow Flaws Under Biaxial Loading Conditions, Part II: Application of a Weibull Stress Analysis of the Cruciform Bend Specimen Using a Hydrostatic Stress Criterion

Cruciform beam fracture mechanics specimensl have been developed in the Heavy Section Steel Technology (HSST) Program at Oak Ridge National Laboratory (ORNL) to introduce a prototypic, far- field, out-of-plane biaxird bending stress component in the test section that approximates the nonlinear biaxial stresses resulting from pressurized-thernxd-shock or pressure-temperature loading of a nuclear reactor pressure vessel (RPV). Matrices of cruciform beam tests were developed to investigate and quantify the effects of temperature, biaxial loading, and specimen size on fracture initiation toughness of two-dimensional (constant depth), shtdlow, surface flaws. Tests were conducted under biaxial load ratios ranging from uniaxial to equibiaxial. These tests demonstrated that biaxial loading can have a pronounced effect on shallow-flaw fracture toughness in the lower transition temperature region for RPV materials. Two and three- parameter Weibull models have been calibrated using a new scheme (developed at the University of Illinois) that maps toughness data from test specimens with distinctly different levels of crack-tip constraint to a small scale yielding (SSY) Weibull stress space. These models, using the new hydrostatic stress criterion in place of the more commonly used maximum principal stress in the kernel of the OW integral definition, have been shown to correlate the experimentally observed biaxiaI effect in cruciform specimens, thereby providing a scaling mechanism between uniaxial and biaxial loading states

Does \u2018bigger\u2019mean \u2018better\u2019? Pitfalls and shortcuts associated with big data for social research

\u2018Big data is here to stay.\u2019 This key statement has a double value: is an assumption as well as the reason why a theoretical reflection is needed. Furthermore, Big data is something that is gaining visibility and success in social sciences even, overcoming the division between humanities and computer sciences. In this contribution some considerations on the presence and the certain persistence of Big data as a socio-technical assemblage will be outlined. Therefore, the intriguing opportunities for social research linked to such interaction between practices and technological development will be developed. However, despite a promissory rhetoric, fostered by several scholars since the birth of Big data as a labelled concept, some risks are just around the corner. The claims for the methodological power of bigger and bigger datasets, as well as increasing speed in analysis and data collection, are creating a real hype in social research. Peculiar attention is needed in order to avoid some pitfalls. These risks will be analysed for what concerns the validity of the research results \u2018obtained through Big data. After a pars distruens, this contribution will conclude with a pars construens; assuming the previous critiques, a mixed methods research design approach will be described as a general proposal with the objective of stimulating a debate on the integration of Big data in complex research projecting

License prices for financially constrained firms

It is often alleged that high auction prices inhibit service deployment. We investigate this claim under the extreme case of financially constrained bidders. If demand is just slightly elastic, auctions maximize consumer surplus if consumer surplus is a convex function of quantity (a common assumption), or if consumer surplus is concave and the proportion of expenditure spent on deployment is greater than one over the elasticity of demand. The latter condition appears to be true for most of the large telecom auctions in the US and Europe. Thus, even if high auction prices inhibit service deployment, auctions appear to be optimal from the consumers’ point of view

Presynaptic actions of 4-Aminopyridine and γ-aminobutyric acid on rat sympathetic ganglia in vitro

Responses to bath-applications of 4-aminopyridine (4-AP) and -aminobutyric acid (GABA) were recorded intracellularly from neurones in the rat isolated superior cervical ganglion. 4-aminopyridine (0.1–1.0 mmol/l) usually induced spontaneous action potentials and excitatory postsynaptic potentials (EPSPs), which were blocked by hexamethonium. Membrane potential was unchanged; spike duration was slightly increased. Vagus nerve B-and C-fibre potentials were prolonged. In 4-AP solution (0.1–0.3 mmol/l), GABA (0.1 mmol/l), 3-aminopropanesulphonic acid or muscimol evoked bursts of spikes and EPSPs in addition to a neuronal depolarization. These bursts, which were not elicited by glycine, glutamate, taurine or (±)-baclofen, were completely antagonised by hexamethonium, tetrodotoxin or bicuculline methochloride. It is concluded that: (a) 4-AP has a potent presynaptic action on sympathetic ganglia; (b) presynaptic actions of GABA can be recorded postsynaptically in the presence of 4-AP; and (c) the presynaptic GABA-receptors revealed in this condition are similar to those on the postsynaptic membrane