oalib

Publish in OALib Journal

ISSN: 2333-9721

APC: Only $99

Submit

Search Results: 1 - 10 of 1302 matches for " Alec Jenkins "
All listed articles are free for downloading (OA Articles)
Page 1 /1302
Display every page Item
Scanned probe imaging of nanoscale magnetism at cryogenic temperatures with a single-spin quantum sensor
Matthew Pelliccione,Alec Jenkins,Preeti Ovartchaiyapong,Christopher Reetz,Eve Emmanuelidu,Ni Ni,Ania C. Bleszynski Jayich
Physics , 2015,
Abstract: High spatial resolution magnetic imaging has driven important developments in fields ranging from materials science to biology. However, to uncover finer details approaching the nanoscale with greater sensitivity requires the development of a radically new sensor technology. The nitrogen-vacancy (NV) defect in diamond has emerged as a promising candidate for such a sensor based on its atomic size and quantum-limited sensing capabilities afforded by long spin coherence times. Although the NV center has been successfully implemented as a nanoscale scanning magnetic probe at room temperature, it has remained an outstanding challenge to extend this capability to cryogenic temperatures, where many solid-state systems exhibit non-trivial magnetic order. Here we present NV magnetic imaging down to 6 K with 6 nm spatial resolution and 3 {\mu}T/$\sqrt{\mbox{Hz}}$ field sensitivity, first benchmarking the technique with a magnetic hard disk sample, then utilizing the technique to image vortices in the iron pnictide superconductor BaFe$_2$(As$_{0.7}$P$_{0.3}$)$_2$ with $T_c$ = 30 K. The expansion of NV-based magnetic imaging to cryogenic temperatures represents an important advance in state-of-the-art magnetometry, which will enable future studies of heretofore inaccessible nanoscale magnetism in condensed matter systems.
Retail Price Optimization from Sparse Demand Data  [PDF]
Philip Thomas, Alec Chrystal
American Journal of Industrial and Business Management (AJIBM) , 2013, DOI: 10.4236/ajibm.2013.33035
Abstract:

It will be shown how the retailer can use economic theory to exploit the sparse information available to him to set the price of each item he is selling close to its profit-maximizing level. The variability of the maximum price acceptable to each customer is modeled using a probability density for demand, which provides an alternative to the conventional demand curve often employed. This alternative way of interpreting retail demand data provides insights into the optimal price as a central measure of a demand distribution. Modeling individuals variability in their maximum acceptable price using a near-exhaustive set of demand densities, it will be established that the optimal price will be close both to the mean of the underlying demand density and to the mean of the Rectangular distribution fitted to the underlying distribution. An algorithm will then be derived that produces a near-optimal price, whatever the market conditions prevailing, monopoly, oligopoly, monopolistic competition or, in the limiting case, perfect competition, based on the minimum of market testing. The algorithm given for optimizing the retail price, even when demand data are sparse, is shown in worked examples to be accurate and thus of practical use to retail businesses.

Generalized Demand Densities for Retail Price Investigation  [PDF]
Philip Thomas, Alec Chrystal
American Journal of Industrial and Business Management (AJIBM) , 2013, DOI: 10.4236/ajibm.2013.33034
Abstract:

The paper introduces generalized demand densities as a new and effective way of conceptualizing and analyzing retail demand. The demand density is demonstrated to contain the same information as the demand curve conventionally used in economic studies of consumer demand, but the fact that it is a probability density sets bounds on its possible behavior, a feature that may be exploited to allow near-exhaustive testing of possible demand scenarios using candidate demand densities. Four such demand densities are examined in detail. The Household Income demand density is based on the assumption that a persons maximum acceptable price (MAP) for an item is proportional to his household after-tax income. The Double Power demand density allows the mode to be located anywhere in the range between zero and the highest MAP possessed by anyone in the target population. The two-parameter, Rectangular demand density, the simplest model that a retailer may employ, has the useful feature that it may be matched relatively easily to any unimodal demand density and hence may act as its approximate proxy. The Kinked demand density is derived from the kinked demand curve sometimes used as a relatively uncomplicated way of conceptualizing the effects of oligopoly. The central measures of each of these demand densities are derived: mean price, mode, median, optimal and, when appropriate, the mean of the matched Rectangular demand density. In a further result arising from the use of demand densities, it is shown that stable trading at the kink price will not occur if the demand curve is kinked and convex.

Explaining the “Buy One Get One Free” Promotion: The Golden Ratio as a Marketing Tool  [PDF]
Philip Thomas, Alec Chrystal
American Journal of Industrial and Business Management (AJIBM) , 2013, DOI: 10.4236/ajibm.2013.38075
Abstract:

Buy-one-get-one-free (BOGOF) promotions are a common feature of retail food markets, but why are they so widespread? The theory of Relative Utility Pricing (RUP) developed in this paper provides an explanation not only for supermarket promotional offers but also for more general pricing of packs of different sizes in supermarkets and on the internet. A clear and simple explanation is given for the two most widely used quantity promotions: BOGOF and 3-for-the-price-of-2. The RUP model may be linked to the theory of iso-elastic utility functions, and this allows the relationships amongst risk-aversion, pack-size ratio and demand elasticity to be explored. “Cautious consumers”, as defined in the paper, are found to be the only sensible target for quantity promotions. It is argued that the needs of cautious consumers of retail commodities will be best addressed if the vendor sets the ratio of successive pack sizes as the square of the Golden Ratio, namely 2.62, and the price-ratio at the Golden Ratio, 1.62. Thus the Golden Ratio may be regarded as a marketing guide for vendors considering both their best interests and those of their customers. This proposition is supported by an analysis showing that higher profits are more likely to come from Golden Ratio sizing than from either BOGOF or 3-for-2 when variable costs lie in most of the upper half of the range that is required for any of these multibuy offers to generate profit. The paper’s theoretical predictions for both pack sizes and prices are supported by examples from the retail sector: grocery, paperback books and electronics.

Using Relative Utility Pricing to Explain Multibuy Prices in Supermarkets and on the Internet  [PDF]
Philip Thomas, Alec Chrystal
American Journal of Industrial and Business Management (AJIBM) , 2013, DOI: 10.4236/ajibm.2013.38078
Abstract:

The Relative Utility Pricing (RUP) model is used to explain the prices for commodities being sold in supermarkets and on the internet. Grocery prices offered by the supermarkets, Tesco, Sainsbury and Waitrose in December 2009 and August 2013, are considered, as well as the prices of electronic items offered by Amazon on the internet at the same dates. The observed price for a pack can be given an explanation in terms of its size relative to the smallest pack considered by the customer (the baseline pack), the price and variable cost associated with the baseline pack and the demand density. The optimal price may be predicted using a profit maximising calculation if these data are available. Even if the vendor’s knowledge of the demand density is poor or non-existent, it is still possible for a vendor knowing his unit variable cost to calculate a useful approximation to the profit-maximising price by using a uniform or Rectangular demand density to represent customer demand. Alternatively, if there are no independent data on the demand density but the prices of the packs are available, it is possible to determine the approximate shape of the demand density leading to those prices. This demand density will then indicate whether the demand is soft or hard, with the Rectangular distribution indicating a neutral market. We consider the vendor to be a large retailer, such as a supermarket, who can obtain the product that he wishes to sell from a variety of suppliers at constant per-unit variable cost and hence marginal cost. Any sales at a price above marginal cost will contribute to profit. The RUP model provides an approximate match to the prices observed for supermarket milk and eggs by adjusting the demand density. A softening of the market for farm retail commodities is revealed between December 2009 and August 2013, fully consistent with the coincident long period of low growth and falling real wages in the UK economy. It is shown how the vendor may use product differentiation to buck this trend. The RUP model explains also the current prices of USB memory sticks, how those prices have evolved and how they are likely to evolve over time.

Resilience: The New Paradigm in Disaster Management—An Australian Perspective  [PDF]
Stephen Jenkins, Stephen Jenkins
World Journal of Engineering and Technology (WJET) , 2015, DOI: 10.4236/wjet.2015.33C020
Abstract:

During past decades, frameworks relating to emergency and disaster management have been based on a risk management approach to prevention/mitigation and preparedness coupled with a strong emphasis on response by police and emergency service organisations. Numerous reviews and inquiries of significant events however have identified significant issues relating to the preparation for such events and the management thereof; in particular, critical shortcomings in the capability of emergency response agencies, their leaders and senior decision-makers. In 2008, the Australian Government, through The First National Security Statement to the Australian Parliament by Prime Minister Rudd, has incorporated non-traditional threats and hazards, such as those posed by the impact of climate change, on the national security agenda. In doing so, the Government has announced a paradigm shift in policy for the nation’s approach to emergency and disaster management, namely a move from “response” to “resilience”. In support of this policy shift, the Australian Government, through the Council of Australian Governments, has endorsed the National Strategy for Disaster Resilience and the Critical Infrastructure Resilience Strategy. These documents make resilience the responsibility of all levels of government, private industry, emergency response agencies, and the community. A review of the reports published following Australian reviews and inquiries into significant events has identified that existing frameworks do not provide the necessary mechanisms for baselining and assessing community resilience, that is, their ability to respond to and recover from significant events. Internationally, indices have been developed for assessing community resilience, however, inherent limitations have also been identified in their scope and application. This paper will review Australian and international events which have led to inquiries that have resulted in criticisms of the emergency and disaster response, as well as introducing the organisational capability and resilience of organisations particularly in the context of climate change.

Gestalt Couples Therapy in the Field of Trauma  [PDF]
Paul Jenkins
Psychology (PSYCH) , 2016, DOI: 10.4236/psych.2016.75072
Abstract:

The field of Gestalt therapy has long had a troubled relationship with mainstream psychotherapy. The decades long assent of cognitive-behavioral and other, more objectively oriented therapies moved Gestalt even further from common acceptance as a valid alternative for treatment. Couple’s therapy, in particular, has not commonly been seen as a natural “fit” for Gestalt practice. The author’s view is that the recent rise of integrated therapy and the need for Evidence-Based Treatment separate from issues of allegiance to a particular school of therapy has created a new opportunity to reconsider Gestalt therapy theory and practice in couple’s work. It is particularly relevant for work with couples in which one or both have been traumatized. Recent developments in Gestalt practice offers a fresh approach for such work, especially in regard to its focus on resolving underlying shame and the need for the couple to develop mutual acceptance at a deep level. Both these therapeutic tasks are vital in work with traumatized clients. These Gestalt tasks can easily be integrated with other, more mainstream models of working with trauma and working couples. An example of this integrated approach is offered to explore the ramifications of the theoretical assertion.

Dynamics of Charge Transfer by Surface Electric Discharges in Atmospheric Air  [PDF]
Alec Houpt, Sergey B. Leonov
Journal of Applied Mathematics and Physics (JAMP) , 2015, DOI: 10.4236/jamp.2015.38132
Abstract:

This work reveals essential details of plasma-surface interaction in atmospheric air that are important for a wide range of applications, beginning from airflow control and up to the high-voltage insulation. The paper discusses experimental data characterizing dynamics of development and kinetics of energy coupling in surface dielectric barrier discharge (SDBD), atmospheric air plasmas sustained over dielectric surfaces, over a wide range of time scales. The experiments have been conducted using microsecond pulse voltage waveform of single and alternating polarities. Time-resolved discharge development and mechanisms of coupling with quiescent air are analyzed using nanosecond gate camera imaging, electrical measurements, and original surface charge sensors. The results demonstrate several new, critically important processes overlooked in previous studies. Specifically, it is shown that SDBD plasmas energy release may be significantly increased by using an optimized waveform.

Extraordinary renditions: reflections upon the war on terror in British and American screen science fiction
Alec Charles
Historia Actual Online , 2010,
Abstract: Como la Guerra Fría influenció cuarenta a os de ciencia ficción televisiva, así la sombra del 11/S formaliza la ciencia ficción popular en los primeros a os del siglo XXI. La destrucción de Nueva York ha ocurrido en muchas películas como El día después de ma ana, Cloverfield, La Guerra de los Mundos y La Leyenda. Como La Invasión, la última trilogía que reinventa la fábula de la Guerra Fría –La invasión de los ladrones de cuerpos, la Guerra de los Mundos y El hombre Omega- para la era neoconservadora, como 28 días después, 28 semanas después, Jericho y el remade Superviventes con un resurgimiento en un escenario post-apocalíptico que adolece de la serie Day of the Triffids. Como Star Trek: Enterprise vuelve su tradicional liberalismo como un ejercicio de patriotera paranoia, Batalla estelar (otro restaurada reliquia de la Guerra Fría) ha presentado una visión más ambigua y problemática de la batalla de la democracia con el fundamentalismo. El re-hecho Doctor Who y Héroes han avanzado similares argumentos de nuevo en el totalizado seudo-utopismo de los cruzados o de los jihadistas a favor del stablishment de un consenso plural. Palabras clave: 11/S, ciencia ficción televisiva, Doctor Who, escenario post-apocalíptico, paranoia patriotera ___________________________ ABSTRACT: As the Cold War influenced forty years of screen science fiction, so the shadow of 9/11 informs popular science fiction in the early twenty-first century. The destruction of New York has recurred in such films as The Day After Tomorrow, Cloverfield, War of the Worlds and I Am Legend. Like The Invasion, the latter pair reinvent Cold War fables – Invasion of the Body Snatchers, War of the Worlds and The Omega Man – for the neoconservative age, while 28 Days Later, 28 Weeks Later, Jericho and the remade Survivors witness a resurgence in post-apocalyptic concerns redolent of Day of the Triffids. While Star Trek: Enterprise turned its franchise’s traditional liberalism into an exercise in jingoistic paranoia, Battlestar Galactica (another restored relic of the Cold War) has presented a much more ambiguous and problematic vision of democracy’s battle with fundamentalism. The reimagined Doctor Who and Heroes have advanced similar arguments against the totalizing pseudo-utopianism of the crusader or the jihadist and in favour of the establishment of a pluralist consensus. Keywords: 9/11; screen science fiction; Doctor Who; post-apocalyptic concerns; jingoistic paranoia
15 years experience with percutaneous mitral commissurotomy
Alec Vahanian
Polish Journal of Cardiology , 2003,
Abstract: Most reports concerning percutaneous mitral commissurotomy (PMC) have been published since 1986. As regards the technique, efficacy, safety, and applicability, the PMC using Inoue balloon is clearly established worldwide. PMC significantly improves valve function; the resting parameters as well as the exercise parame-ters are improved after PMC. Risks are related to the experience of the team performing the procedure and also, but to a lesser extent, to the clinical status of the patient. The most important complication of the procedure is the occurrence of traumatic mitral regurgitation which is seen in around 5% of cases. Long-term results are satisfactory and around 60% of the patients remain alive without re-intervention with no symptoms in the period of observation exceeding 10 years. The exact incidence of restenosis has been estimated around 40% at seven years. PMC should not be performed in patients with only moderate mitral stenosis becau-se there is still a small inherent risk in the technique, the threshold commonly admitted is a valve area of <1.5 cm2. Left atrial thrombosis is a contraindication for the technique for most authors. PMC is also contraindi-cated in patients with massive calcification, those with absence of commissural fusion which could occur after previous surgery, or in cases with more than moderate mitral regurgitation. Finally, PMC should not be performed if severe aortic valve disease, mostly aortic stenosis, is associated with mitral stenosis. In conclusion the good results that have been obtained with PMC enable us to say that this technique which is the second most important percutaneous technique in cardiology, has an important place in the treatment of mitral stenosis besides and not against surgery because PMC and surgery are complementary each being applicable at the appropriate stage of the disease.
Page 1 /1302
Display every page Item


Home
Copyright © 2008-2017 Open Access Library. All rights reserved.