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Opportunities
Kinds of Opportunities Terms modified by Opportunities Selected AbstractsEFFECTS OF ATTRACTIVENESS, OPPORTUNITY AND ACCESSIBILITY TO BURGLARS ON RESIDENTIAL BURGLARY RATES OF URBAN NEIGHBORHOODSCRIMINOLOGY, Issue 3 2003WIM BERNASCO This study assesses the effects of attractiveness, opportunity and accessibility to burglars on the residential burglary rates of urban neighborhoods, combining two complementary lines of investigation that have been following separate tracks in the literature. As a complement to standard measures of attractiveness and opportunity, we introduce and specify a spatial measure of the accessibility of neighborhoods to burglars. Using data on about 25, 000 attempted and completed residential burglaries committed in the period 1996,2001 in the city of The Hague, the Netherlands, we study the variation in burglary rates across its 89 residential neighborhoods. Our results suggest that all three factors, attractiveness, opportunity and accessibility to burglars, pull burglars to their target neighborhoods. [source] IS EQUALITY OF OPPORTUNITY POLITICALLY FEASIBLE?ECONOMICS & POLITICS, Issue 1 2005Stefan Zink We develop a political-economy model where the amount of education subsidies is determined in a majority vote and spending is financed by revenues from taxation. Our analysis demonstrates that limiting the extent of subsidization and thus excluding the poor from gaining enough education can be a political equilibrium. Despite being the main beneficiaries of subsidies, the politically decisive middle class hesitates to extend monetary benefits, since improved access to higher education diminishes the return to education. Moreover, a non-monotone relation between inequality and the extent of redistribution through tax-financed educational subsidies obtains. [source] THE FEMINIZATION OF TEACHING AND THE PRACTICE OF TEACHING: THREAT OR OPPORTUNITY?EDUCATIONAL THEORY, Issue 4 2006Morwenna Griffiths She outlines a feminist theory of practice that draws critically on theories of embodiment, diversity, and structures of power to show that any practice is properly seen as fluid, leaky, and viscous. Examining different and competing understandings of "feminization", referring either to the numbers of women in teaching or to a culture associated with women , Griffith argues that concerns about increasing number of women teachers are misplaced. She complicates the cultural question, observing that masculine practices have a hegemonic form while feminized practices have developed in resistance to these, and she ultimately argues that hegemonic masculinity, not feminization, is the problem because it drives out diversity. Griffiths concludes that the leaky, viscous practices of teaching would benefit from the increased diversity and decreased social stratification feminization brings to the profession. [source] ON THE OPPORTUNITY FOR SEXUAL SELECTION, THE BATEMAN GRADIENT AND THE MAXIMUM INTENSITY OF SEXUAL SELECTIONEVOLUTION, Issue 7 2009Adam G. Jones Bateman's classic paper on fly mating systems inspired quantitative study of sexual selection but also resulted in much debate and confusion. Here, I consider the meaning of Bateman's principles in the context of selection theory. Success in precopulatory sexual selection can be quantified as a "mating differential," which is the covariance between trait values and relative mating success. The mating differential is converted into a selection differential by the Bateman gradient, which is the least squares regression of relative reproductive success on relative mating success. Hence, a complete understanding of precopulatory sexual selection requires knowledge of two equally important aspects of mating patterns: the mating differential, which requires a focus on mechanisms generating covariance between trait values and mating success, and the Bateman gradient, which requires knowledge of the genetic mating system. An upper limit on the magnitude of the selection differential on any sexually selected trait is given by the product of the standard deviation in relative mating success and the Bateman gradient. This latter view of the maximum selection differential provides a clearer focus on the important aspects of precopulatory sexual selection than other methods and therefore should be an important part of future studies of sexual selection. [source] EXPERIMENTAL EVIDENCE THAT SEXUAL CONFLICT INFLUENCES THE OPPORTUNITY, FORM AND INTENSITY OF SEXUAL SELECTIONEVOLUTION, Issue 9 2008Matthew D. Hall Sexual interactions are often rife with conflict. Conflict between members of the same sex over opportunities to mate has long been understood to effect evolution via sexual selection. Although conflict between males and females is now understood to be widespread, such conflict is seldom considered in the same light as a general agent of sexual selection. Any interaction between males or females that generates variation in fitness, whether due to conflict, competition or mate choice, can potentially influence sexual selection acting on a range of male traits. Here we seek to address a lack of direct experimental evidence for how sexual conflict influences sexual selection more broadly. We manipulate a major source of sexual conflict in the black field cricket, Teleogryllus commodus, and quantify the resulting changes in the nature of sexual selection using formal selection analysis to statistically compare multivariate fitness surfaces. In T. commodus, sexual conflict occurs over the attachment time of an external spermatophore. By experimentally manipulating the ability of males and females to influence spermatophore attachment, we found that sexual conflict significantly influences the opportunity, form, and intensity of sexual selection on male courtship call and body size. When males were able to harass females, the opportunity for selection was smaller, the form of selection changed, and sexual selection was weaker. We discuss the broader evolutionary implications of these findings, including the contributions of sexual conflict to fluctuating sexual selection and the maintenance of additive genetic variation. [source] ADAPTATION AND INTRAINDIVIDUAL VARIATION IN SALES OUTCOMES: EXPLORING THE INTERACTIVE EFFECTS OF PERSONALITY AND ENVIRONMENTAL OPPORTUNITYPERSONNEL PSYCHOLOGY, Issue 2 2006GREG L. STEWART Many practices in the field of industrial-organizational psychology assume that individual performance is stable across time; yet, little is actually known about the extent to which performance varies within individuals. We specifically address this issue by exploring the longitudinal influence of a situational opportunity (referrals received from the central office) on intraindividual performance outcomes of sales representatives. We also explore Conscientiousness and Openness to Experience as traits that explain variation in adaptation to changes in referrals. Our results show that more weekly variation in individual performance resides within individuals than between individuals. A majority of this variance is explained by the situational opportunity of referrals. Furthermore, the positive relationship between referrals and outcomes is stronger for sales representatives high on Conscientiousness, but weaker for representatives high on Openness to Experience. [source] A GREAT OPPORTUNITY AHEAD FOR SURGICAL PUBLISHING,ANZ JOURNAL OF SURGERY, Issue 12 2006Robert J. S. Thomas Editor-in-Chief No abstract is available for this article. [source] Biodiversity Conservation in Agricultural Landscapes: Challenges and Opportunities of Coffee Agroforests in the Western Ghats, IndiaCONSERVATION BIOLOGY, Issue 2 2010CLAUDE A. GARCIA agroforestería de café; Ghats Occidentales; medios de vida; mosaicos paisajísticos; proyectos integrados de conservación y desarrollo Abstract:,The new approaches advocated by the conservation community to integrate conservation and livelihood development now explicitly address landscape mosaics composed of agricultural and forested land rather than only protected areas and largely intact forests. We refer specifically to a call by Harvey et al. (2008) to develop a new approach based on six strategies to integrate biodiversity conservation with sustainable livelihoods in Mesoamerican landscape mosaics. We examined the applicability of this proposal to the coffee agroforests of the Western Ghats, India. Of the six strategies, only one directly addresses livelihood conditions. Their approach has a clear emphasis on conservation and, as currently formulated risks repeating the failures of past integrated conservation and development projects. It fails to place the aspirations of farmers at the core of the agenda. Thus, although we acknowledge and share the broad vision and many of the ideas proposed by this approach, we urge more balanced priority setting by emphasizing people as much as biodiversity through a careful consideration of local livelihood needs and aspirations. Resumen:,Los nuevos enfoques recomendados por la comunidad de conservación para integrar la conservación y el desarrollo ahora abordan explícitamente los mosaicos paisajísticos compuestos de tierras agrícolas y forestales en lugar de solo áreas protegidas y bosques casi intactos. Basado en seis estrategias para integrar la conservacion de la biodiversidad con modos de vida sustentables en los mosaicos paisajisticos de Mesoamerica. Nos referimos específicamente a la llamada de Harvey et al. (2008) para desarrollar un enfoque nuevo basado en seis estrategias para congraciar la conservación de la biodiversidad con modos de vida sustentables en los mosaicos paisajísticos de Mesoamérica. Examinamos la aplicabilidad de esta propuesta en los agrobosques de café de los Ghats occidentales en la India. Solo una de las seis estrategias mencionadas aborda directamente las condiciones de vida. La propuesta tiene un claro énfasis en la conservación y, tal como está formulada actualmente, falla en colocar las aspiraciones de los campesinos en el centro de la agenda. Corre pues el riesgo de repetir los fracasos de pasados proyectos integrados de conservación y desarrollo. Por lo tanto, aunque reconocemos y compartimos la amplia visión y muchas de las ideas de esta llamada, insistimos en una definición de prioridades balanceada que enfatice a la gente tanto como a la biodiversidad mediante una consideración cuidadosa de las necesidades y aspiraciones de los habitantes locales. [source] Incentives and Opportunities to Manage Earnings around Option Grants,CONTEMPORARY ACCOUNTING RESEARCH, Issue 3 2009Terry A. Baker First page of article [source] The Impact of Technological Opportunities and Innovative Capabilities on Firms' Output InnovationCREATIVITY AND INNOVATION MANAGEMENT, Issue 3 2003María J. Oltra In this study, we analyse the effect that external sources of knowledge and absorptive capacity exert on a firm's output innovation. In addition, we examine the moderating influence of absorptive capacity on the effect that technological opportunities have on output innovation. Empirical research was carried out on a sample of 91 Spanish firms from the ceramic tile industry. Absorptive capacity is operationalized by ,systematic or continuous R&D' and output innovation by ,percentage of sales from new products'. Technological opportunities are divided into several industry and non-industry related variables. Our results show the positive effect that both the industry's technological opportunities and a systematic approach to R&D exert on output innovation. Moreover, firms with a systematic approach to R&D usually achieve higher innovation output than firms which do not follow this approach. The innovation results of this second group decrease as a result of embedded technology acquisition. [source] A Modeling Framework for Supply Chain Simulation: Opportunities for Improved Decision Making,DECISION SCIENCES, Issue 1 2005D. J. Van Der Zee ABSTRACT Owing to its inherent modeling flexibility, simulation is often regarded as the proper means for supporting decision making on supply chain design. The ultimate success of supply chain simulation, however, is determined by a combination of the analyst's skills, the chain members' involvement, and the modeling capabilities of the simulation tool. This combination should provide the basis for a realistic simulation model, which is both transparent and complete. The need for transparency is especially strong for supply chains as they involve (semi)autonomous parties each having their own objectives. Mutual trust and model effectiveness are strongly influenced by the degree of completeness of each party's insight into the key decision variables. Ideally, visual interactive simulation models present an important communicative means for realizing the required overview and insight. Unfortunately, most models strongly focus on physical transactions, leaving key decision variables implicit for some or all of the parties involved. This especially applies to control structures, that is, the managers or systems responsible for control, their activities and their mutual attuning of these activities. Control elements are, for example, dispersed over the model, are not visualized, or form part of the time-indexed scheduling of events. In this article, we propose an alternative approach that explicitly addresses the modeling of control structures. First, we will conduct a literature survey with the aim of listing simulation model qualities essential for supporting successful decision making on supply chain design. Next, we use this insight to define an object-oriented modeling framework that facilitates supply chain simulation in a more realistic manner. This framework is meant to contribute to improved decision making in terms of recognizing and understanding opportunities for improved supply chain design. Finally, the use of the framework is illustrated by a case example concerning a supply chain for chilled salads. [source] The Rapid Rise of Supermarkets in Latin America: Challenges and Opportunities for DevelopmentDEVELOPMENT POLICY REVIEW, Issue 4 2002Thomas Reardon First page of article [source] Limited Opportunities for Paramedic Student Endotracheal Intubation Training in the Operating RoomACADEMIC EMERGENCY MEDICINE, Issue 10 2006Bradford D. Johnston MD Abstract Background Paramedics, who often are the first to provide emergency care to critically ill patients, must be proficient in endotracheal intubation (ETI). Training in the controlled operating room (OR) setting is a common method for learning basic ETI technique. Objectives To determine the quantity and nature of OR ETI training currently provided to paramedic students. Methods The authors surveyed directors of paramedic training programs accredited by the Commission on Accreditation of Allied Health Education Programs. An anonymous 12-question, structured, closed-response survey instrument was used that requested information regarding the duration and nature of OR training provided to paramedic students. The results were analyzed by using descriptive statistics. Results From 192 programs, 161 completed surveys were received (response rate, 85%). OR training was used at 156 programs (97%) but generally was limited (median, 17,32 hours per student). Half of the programs provided fewer than 16 OR hours per student. Students attempted a limited number of OR ETI (median, 6,10 ETI). Most respondents (61%) reported competition from other health care students for OR ETI. Other identified hindering factors included the increasing OR use of laryngeal mask airways and physicians' medicolegal concerns. Respondents from 52 (33%) programs reported a recent reduction in OR access, and 56 (36%) programs expected future OR opportunities to decrease. Conclusions Despite its key role in airway management education, the quantity and nature of OR ETI training that is available to paramedic students is limited in comparison to that available to other ETI providers. [source] Spain's greatest and most recent mine disasterDISASTERS, Issue 1 2008Flor Ma. On 25 April 1998, the mineral waste retaining wall at the Swedish-owned pyrite mine at Aznalcóllar (Seville, Spain) burst,2 causing the most harmful environmental and socio-economic disaster in the history of the River Guadiamar basin. The damage was so great that the regional government decided in May 1998 to finance a comprehensive, multidisciplinary research initiative with the objective of eradicating or at least minimising all of the negative social, economic and environmental impacts. This paper utilises a Strengths, Weaknesses, Opportunities and Threats (SWOT) analysis to identify eight strategic measures aimed at providing policymakers with key guidelines on implementing a sustainable development model, in a broad sense. Empirical evidence, though, reveals that, to date, major efforts to tackle the negative impacts have centred on environmental concerns and that the socio-economic consequences have not been completely mitigated. [source] Advanced Opportunities for Student Education in Emergency MedicineACADEMIC EMERGENCY MEDICINE, Issue 10 2004Charissa B. Pacella MD Abstract Many medical students are excited about emergency medicine (EM) following a standard clerkship and seek out additional learning opportunities. An advanced EM elective may accomplish several educational goals, including development of clinical skills in evaluating the undifferentiated patient, broader exploration of the field of EM, and more focused study of one particular aspect of EM. Previously cited examples include pediatric EM, medical toxicology, occupational medicine, sports medicine, and EM research. Numerous other EM specialty courses for senior medical students are emerging, as reflected in the "Undergraduate Rotations" listings on the Society for Academic Emergency Medicine. A few examples drawn from the list include emergency ultrasound, international EM, wilderness medicine, disaster medicine, geriatric EM, and hyperbaric medicine. Educators aspiring to develop, or in the process of developing, an advanced EM elective may benefit from a brief overview of necessary course considerations, including didactic format, the clinical role of the medical student in the emergency department, and involvement with patient procedures. Suggestions are made regarding additional educational opportunities, including follow-up of patients seen in the emergency department and development of an emergency department radiology case file. This article also addresses several related concerns, including suggested prerequisites, administration and cost considerations, appropriate didactic topics, and methods for evaluating students. Several EM subspecialty areas, namely pediatric EM, medical toxicology, and out-of-hospital care, are specifically discussed. Formal advanced cardiac life support training is also often included in an advanced EM elective and is briefly discussed. The overall intent of this article is to provide medical student educators with resources and ideas to assist them in developing a unique advanced EM elective. [source] Avoiding Misconception, Misuse, and Missed Opportunities: The Collection of Verbal Reports in Educational Achievement TestingEDUCATIONAL MEASUREMENT: ISSUES AND PRACTICE, Issue 4 2004Jacqueline P. Leighton The collection of verbal reports is one way in which cognitive and developmental psychologists gather data to formulate and corroborate models of problem solving. The current use of verbal reports to design and validate educational assessments reflects the growing trend to fuse cognitive psychological research and educational measurement. However, doubts about the trustworthiness or accuracy of verbal reports may suggest a potential reversal of this trend. Misconceptions about the trustworthiness of verbal reports could signal misuse of verbal reports and, consequently, waning interest and missed opportunities in the description of cognitive models of test performance. In this article, misconceptions of verbal reports are addressed by (a) discussing the value of cognitive models for educational achievement testing; (b) addressing pertinent issues in the collection of verbal reports from students; and (c) concluding with avenues for a more productive union between cognitive psychological research and educational measurement. [source] Label-Free Impedance Biosensors: Opportunities and ChallengesELECTROANALYSIS, Issue 12 2007Jonathan Abstract Impedance biosensors are a class of electrical biosensors that show promise for point-of-care and other applications due to low cost, ease of miniaturization, and label-free operation. Unlabeled DNA and protein targets can be detected by monitoring changes in surface impedance when a target molecule binds to an immobilized probe. The affinity capture step leads to challenges shared by all label-free affinity biosensors; these challenges are discussed along with others unique to impedance readout. Various possible mechanisms for impedance change upon target binding are discussed. We critically summarize accomplishments of past label-free impedance biosensors and identify areas for future research. [source] How Opportunities Develop in Social EntrepreneurshipENTREPRENEURSHIP THEORY AND PRACTICE, Issue 4 2010Patricia Doyle Corner The purpose of this article was to extend existing research on opportunity identification in the social entrepreneurship literature through empirically examining this phenomenon. We used an inductive, theory-building design that surfaced patterns in social value creation across multiple case studies. The patterns showed actors seeing a social need and prospecting ideas that could address it. Data also revealed multiple, not individual, actors, dynamically engaged in interactions that nudged an opportunity into manifestation. Also, data suggested complementarities to effectuation and rational/economic processes that are divergent theoretical approaches to the study of entrepreneurship to date. [source] Beyond the Single-Person, Single-Insight Attribution in Understanding Entrepreneurial OpportunitiesENTREPRENEURSHIP THEORY AND PRACTICE, Issue 5 2007Dimo Dimov This article helps develop the creativity perspective within entrepreneurship in two ways. First, it elaborates on the nature of opportunity as a creative product. Rather than viewing opportunities as single insights, it suggests that they are emerging through the continuous shaping and development of (raw) ideas that are acted upon. Second, rather than attributing them to a particular individual, it highlights the contextual and social influences that affect the generation and shaping of ideas. This helps move entrepreneurship research beyond the single-person, single-insight attribution that currently permeates it. [source] Opportunities and constraints in the adaptation of technology for the diagnosis of bacterial plant diseases , experience from Tanzania,EPPO BULLETIN, Issue 3-4 2000R. Black In order to improve diagnostic services and plant quarantine capabilities in Tanzania, the techniques of semi-selective media, the BACTID system, metabolic profiling (Biolog), indirect enzyme-linked immunosorbent assays (ELISA) and polymerase chain reaction (PCR) were assessed for suitability with the existing facilities for the diagnosis and detection of plant-pathogenic bacteria of vegetables. Field-collected samples as well as farmers' own and commercial germplasm were used in studies involving Ralstonia solanacearum, Clavibacter michiganensis subsp. michiganensis and Xanthomonas campestris pv. vesicatoria in Solanaceae and X. c. pv. campestris in Brassicaceae. Each of the techniques was used successfully with one or more of the target pathogens; each had advantages depending on the speed, sensitivity and specificity required, as well as the costs of carrying out the diagnosis. However, constraints emerged relating to the use and disposal of materials such as plastic Petri dishes and toxic substances. The more familiar underlying constraints of high cost and poor availability of consumables and erratic water and electricity supply continued to present problems. These problems will be discussed in relation to the development of an integrated and sustainable approach to the provision of routine diagnostic services. [source] Cryptic Kin Selection: Kin Structure in Vertebrate Populations and Opportunities for Kin-Directed CooperationETHOLOGY, Issue 3 2010Ben J. Hatchwell Animal societies of varying complexity have been the favoured testing ground for inclusive fitness theory, and there is now abundant evidence that kin selection has played a critical role in the evolution of cooperative behaviour. One of the key theoretical and empirical findings underlying this conclusion is that cooperative systems have a degree of kin structure, often the product of delayed dispersal, that facilitates interactions with relatives. However, recent population genetic studies have revealed that many non-cooperative animals also have kin-structured populations, providing more cryptic opportunities for kin selection to operate. In this article, I first review the evidence that kin structure is widespread among non-cooperative vertebrates, and then consider the various contexts in which kin selection may occur in such taxa, including: leks, brood parasitism, crèches, breeding associations, territoriality and population dynamics, foraging and predator deterrence. I describe the evidence that kin-selected benefits arise from interacting with kin in each of these contexts, notwithstanding the potential costs of kin competition and inbreeding. I conclude that as the tools required to determine population genetic structure are readily available, measurement of kin structure and the potential for kin selection on a routine basis is likely to reveal that this process has been an important driver of evolutionary adaptation in many non-cooperative as well as cooperative species. [source] Improving Opportunities for Adult Learning in the Acceding and Candidate Countries of Central and Eastern EuropeEUROPEAN JOURNAL OF EDUCATION, Issue 1 2004Haralabos Fragoulis First page of article [source] THE EVOLUTION OF FEMALE MATING PREFERENCES: DIFFERENTIATION FROM SPECIES WITH PROMISCUOUS MALES CAN PROMOTE SPECIATIONEVOLUTION, Issue 10 2006Mark A. McPeek Abstract Females of many species are frequently courted by promiscuous males of their own and other closely related species. Such mating interactions may impose strong selection on female mating preferences to favor trait values in conspecific males that allow females to discriminate them from their heterospecific rivals. We explore the consequences of such selection in models of the evolution of female mating preferences when females must interact with heterospecific males from which they are completely postreproductively isolated. Specifically, we allow the values of both the most preferred male trait and the tolerance of females for males that deviate from this most preferred trait to evolve. Also, we consider situations in which females base their mating decisions on multiple male traits and must interact with males of multiple species. Females will rapidly differentiate in preference when they sometimes mistake heterospecific males for suitable mates, and the differentiation of female preference will select for conspecific male traits to differentiate as well. In most circumstances, this differentiation continues indefinitely, but slows substantially once females are differentiated enough to make mistakes rare. Populations of females with broader preference functions (i.e., broader tolerance for males with trait values that deviate from females most preferred values) will evolve further to differentiate if the shape of the function cannot evolve. Also, the magnitude of separation that evolves is larger and achieved faster when conspecific males have lower relative abundance. The direction of differentiation is also very sensitive to initial conditions if females base their mate choices on multiple male traits. We discuss how these selection pressures on female mate choice may lead to speciation by generating differentiation among populations of a progenitor species that experiences different assemblages of heterospecifics. Opportunities for differentiation increase as the number of traits involved in mate choice increase and as the number of species involved increases. We suggest that this mode of speciation may have been particularly prevalent in response to the cycles of climatic change throughout the Quaternary that forced the assembly and disassembly of entire communities on a continentwide basis. [source] Theorizing in Family Gerontology: New Opportunities for Research and PracticeFAMILY RELATIONS, Issue 5 2006Karen A. Roberto Abstract: We examine the extent to which theory has been used in empirical studies of families in later life, identify prevalent types of theoretical frameworks, and assess connections between theory and both focal topics and analytic methods in the family gerontology literature. The paper is based on content and methodological analysis of 838 empirical articles with a family-level focus published in 13 social science journals during the 1990s. Approximately one half of the articles included theory, with micro-interpretive (social psychological) theories being used most often to guide and inform research and practice. To advance the field and understand better the intricacies of family life among older adults, we suggest that investigators and practitioners explicitly incorporate theoretical frameworks into their endeavors. [source] Stock Liquidity and Investment Opportunities: Evidence from Index AdditionsFINANCIAL MANAGEMENT, Issue 3 2006John R. Becker-Blease We examine the relation between stock liquidity and investment opportunities in a sample of firms experiencing an exogenous liquidity shock. We find a positive relation between changes in capital expenditures and changes in stock liquidity, indicating that stock liquidity influences corporate investment decisions. This relation is robust to alternative measures of growth opportunities, and is consistent with a liquidity premium in equity returns. That is, an increase in liquidity effectively expands the set of positive NPV projects because it reduces the cost of capital. The results suggest that liquidity-enhancing events benefit shareholders by increasing the pool of viable growth opportunities. [source] Assets in Place, Growth Opportunities, and IPO ReturnsFINANCIAL MANAGEMENT, Issue 3 2005Kee H. Chung We consider a simple model positing that initial public offering price is equal to the present value of an entity's assets in place and growth opportunities. The model predicts that initial return is positively related to both the size and risk of growth opportunities. Consistent with this prediction, we find initial return to be positively related to both the fraction of the offer price that is accounted for by the present value of growth opportunities and various proxies of issue uncertainty. We also find that IPO investors equate one dollar of growth opportunities to approximately three quarters of tangible assets. [source] Opportunities for ultra-high resolution analysis of essential oils using comprehensive two-dimensional gas chromatography: a reviewFLAVOUR AND FRAGRANCE JOURNAL, Issue 3 2003Robert Shellie Abstract In comprehensive 2D gas chromatography, the entire sample is simultaneously subjected to analysis on two capillary columns. By using a suitable modulation interface between the primary and secondary columns, hundreds of fast, second-dimension chromatograms are produced. The data from these chromatograms are treated such that a 3D surface plot or a 2D contour plot of the components' individual retention times, on each column, as well as peak responses, are represented. In a properly tuned comprehensive 2D chromatogram, the individual sample components are spread throughout a 2D separation space, providing a signi,cant increase in the probability of resolving a greater number of sample components without increasing the analysis time. Comprehensive 2D,GC has proved useful for high-resolution conventional essential oil analysis as well as high-resolution enantioselective essential oil analysis. Combining comprehensive 2D,GC with either a quadrupole or time-of-,ight mass spectrometer gives a powerful 3D analysis technique, which is extremely effective for complex sample analysis. The present status and opportunities arising from these ultra-high resolution approaches are discussed herein. Copyright © 2003 John Wiley & Sons, Ltd. [source] Dealing with Timing and Synchronization in Opportunities for Joint Activity ParticipationGEOGRAPHICAL ANALYSIS, Issue 3 2010Tijs Neutens The ability of people to access opportunities offered by the built environment is circumscribed by various sets of space,time constraints, including the requirements to meet other persons at particular times and places to undertake activities together. While models of space,time accessibility recognize that joint activities may constrain the performance of activities in space and time, their specifications do not explicitly acknowledge the opportunities that individuals of a group have for joint activity participation. Therefore, this article focuses on joint activity participation and argues that collective activity decisions are the outcome of a complex process involving various aspects of timing, synchronization, and social hierarchy. The utility-theoretic model proposed here quantifies the extent to which opportunities can be jointly accessed by a particular group of people within a specific time period. Central to the approach are three key variables: the attractiveness of an opportunity, the time available for activity participation, and the travel time to an activity location. Because of the multiperson character of joint activities, the determination of these variables is subject to individual preferences, privileges, and power differentials within a group. Specific attention is given to how time-of-day and synchronization effects influence the opportunities accessible to a group of individuals. The impact of these factors on joint accessibility is illustrated by a real-world example of an everyday rendezvous scenario. The outcomes of a simulation exercise suggest that time-of-day and synchronization effects significantly affect the benefits that can be gained from opportunities for joint activities. La capacidad de acceso a las oportunidades que los entornos construidos (como las ciudades) ofrecen a las personas, está limitada por un conjunto diverso de restricciones espacio-temporales. Entre ellas se incluyen los requisitos para coincidir y encontrarse con otras personas en determinados momentos y lugares con el fin de realizar actividades conjuntas. Los modelos de accesibilidad comunes reconocen que las actividades conjuntas pueden limitar el ejercicio de actividades en el espacio y el tiempo. Sin embargo, sus especificaciones no reconocen explícitamente las oportunidades disponibles a todos los individuos de un grupo para participar de una actividad conjunta. Es en este contexto y dadas las limitaciones descritas que este artículo se centra en la participación de individuos en actividades conjuntas y propone el argumento que la toma de decisiones relacionadas con dichas actividades son el resultado de un proceso complejo que involucra varios aspectos de temporización (programación temporal), sincronización, y jerarquía social. El modelo teórico de utilidad que se propone aquí cuantifica el grado en que las oportunidades pueden ser evaluadas en forma conjunta por un grupo de personas particular dentro de un período de tiempo específico. El marco general propuesto por los autores se basa en tres variables fundamentales: el atractivo de una oportunidad, el tiempo disponible para la participación de la actividad, y el tiempo de desplazamiento al lugar donde se lleva a cabo actividad. Debido al carácter particular de estas actividades (que involucran múltiples participantes), la determinación de estas variables está sujeta a preferencias individuales, a privilegios y a diferencias de poder dentro de un grupo. El presente estudio además presta atención especial a la forma en la que la hora del día y los efectos de sincronización pueden influenciar la disponibilidad de oportunidades para un grupo determinado de individuos. El impacto de estos factores sobre la accesibilidad agregada de actividades conjuntas es ejemplificado por los autores mediante un caso del mundo real que utiliza escenarios de encuentros diarios entre personas. Los resultados de este ejercicio de simulación sugieren que los efectos de la hora del día y la sincronización afectan significativamente los beneficios que se pueden obtener a partir las oportunidades disponibles para acceder a y realizar actividades conjuntas. [source] Clubs, Spades, Diamonds and Disadvantage: the Geography of Electronic Gaming Machines in MelbourneGEOGRAPHICAL RESEARCH, Issue 1 2001D.C. Marshall Opportunities to gamble, particularly on electronic gaming machines (EGMs) have been rapidly increasing in Australia during the 1990s. The increase in expenditure on gambling and the related problems have subsequently become a growing concern, particularly in relation to disadvantaged sectors of the population. Given this, the development of a geography of gambling is an important step in understanding the implications of this rapidly expanding industry. This paper addresses this issue at two distinct geographical scales in metropolitan Melbourne and considers the distribution of EGMs in relation to levels of economic well-being. Findings suggest that patterns evident at the wider Melbourne scale of greater concentration of EGMs in less advantaged regions are also reflected at a local level. These findings are related to the wider issues of accessibility to gambling facilities and problem gambling. [source] Monsoon in the Americas: Opportunities and ChallengesGEOGRAPHY COMPASS (ELECTRONIC), Issue 5 2009Thomas M. Rickenbach This article presents a comparative review of the North and South America Monsoon Systems and highlights the challenges and opportunities presented to those regions by the seasonal rains. Monsoon precipitation represents a major component of the water resources available to the southwestern US and to Brazil. Although each system shares classical features of the well-known southwest Indian monsoon, water use, agriculture, public safety, and energy policy in these two countries have been shaped by the unique regional complexities of monsoon rain across each region. A comparison between these two systems may offer perspective for ways by which these societies may adapt to current and future challenges, and take advantage of new opportunities. [source] | ||||||||||||||||||||||||||||||||||||||||