Costly

Distribution by Scientific Domains
Distribution within Life Sciences

Kinds of Costly

  • very costly

  • Terms modified by Costly

  • costly information
  • costly state verification

  • Selected Abstracts


    Experimentally Constrained Virulence is Costly for Common Cuckoo Chicks

    ETHOLOGY, Issue 1 2009
    Grim
    Chicks of some avian brood parasites show high virulence by eliminating all host progeny in the nest whereas others develop in the presence of host nestmates. Common cuckoo (Cuculus canorus) chicks are typically highly virulent parasites as they attempt to evict all host eggs and chicks soon after hatching. However, several features of nest design, including steep walls and/or cavity nests, may effectively prevent cuckoo hatchlings from evicting nestmates. A previous observational study showed low success of cuckoo chicks in evicting progeny of a cavity nester host, the redstart (Phoenicurus phoenicurus) but cuckoo chicks showed low survival both when reared alone or in mixed broods with host nestmates. Whether poor cuckoo performance was caused by eviction costs and/or by the effect of presence of host chicks per se remains unclear. We experimentally cancelled any potential eviction costs by removing host eggs immediately after the cuckoo hatched and creating mixed broods 5 days later when the eviction instinct of the cuckoo already ceased. Cuckoos that were forced to compete with host nestlings experienced lower provisioning rates, poorer growth, and lower fledging success than control lone cuckoos. Cuckoos in mixed broods that survived until fledging fledged later, and at lower masses, than those in the sole cuckoo group. Thus, the cuckoo gens specializing on redstarts is similar to other cuckoo gentes, whose chicks are more successful in evicting host nestmates, and it does not benefit from the presence of host brood. Cohabitation with host nestlings then should be viewed as a maladaptive by-product of host cavity nest design. [source]


    Presidential Address, Committing to Commit: Short-term Debt When Enforcement Is Costly

    THE JOURNAL OF FINANCE, Issue 4 2004
    Douglas W. Diamond
    ABSTRACT In legal systems with expensive or ineffective contract enforcement, it is difficult to induce lenders to enforce debt contracts. If lenders do not enforce, borrowers will have incentives to misbehave. Lenders have incentives to enforce given bad news when debt is short-term and subject to runs caused by externalities across lenders. Lenders will not undo these externalities by negotiation. The required number of lenders increases with enforcement costs. A very high enforcement cost can exceed the ex ante incentive benefit of enforcement. Removing lenders' right to immediately enforce their debt with a "bail-in" can improve the ex ante incentives of borrowers. [source]


    Horizontal Roadway Curvature Computation Algorithm Using Vision Technology

    COMPUTER-AIDED CIVIL AND INFRASTRUCTURE ENGINEERING, Issue 2 2010
    Yichang (James) Tsai
    However, collecting such data is time-consuming, costly, and dangerous using traditional, manual surveying methods. It is especially difficult to perform such manual measurement when roadways have high traffic volumes. Thus, it would be valuable for transportation agencies if roadway curvature data could be computed from photographic images taken using low-cost digital cameras. This is the first article that develops an algorithm using emerging vision technology to acquire horizontal roadway curvature data from roadway images to perform roadway safety assessment. The proposed algorithm consists of four steps: (1) curve edges image processing, (2) mapping edge positions from an image domain to the real-world domain, (3) calibrating camera parameters, and (4) calculating the curve radius and center from curve points. The proposed algorithm was tested on roadways having various levels of curves and using different image sources to demonstrate its capability. The ground truth curvatures for two cases were also collected to evaluate the error of the proposed algorithm. The test results are very promising, and the computed curvatures are especially accurate for curves of small radii (less than 66 m/200 ft) with less than 1.0% relative errors with respect to the ground truth data. The proposed algorithm can be used as an alternative method that complements the traditional measurement methods used by state DOTs to collect roadway curvature data. [source]


    Dynamic range expansion of receiver by using optimized gain adjustment for high-field MRI

    CONCEPTS IN MAGNETIC RESONANCE, Issue 4 2010
    C.H. Oh
    Abstract In high-field magnetic resonance imaging (MRI) system, the signal-to-noise ratio of MR signal is so high that the receiver frequently cannot cover the full dynamic range of the MR signal. Although this problem can be overcome by using a compander (compressor and expander) composed of logarithmic amplifiers and a ROM table to retrieve the nonlinearity of the logarithmic amplifiers or by simply increasing the number of bits of analog-to-digital converter, the methods can be costly and complex or even impossible for most commercial systems. In addition, the spectrometer has to be specifically designed to operate in those modes. In this article, we developed a simple dynamic range improvement method using a receiver with optimized variable gain control in which function can be implemented without any hardware modification to the spectrometer, if the spectrometer can do gain control during a scan. Simulations as well as experiments for the brain and resolution phantom have been performed, and the results demonstrate the utility of the proposed method. © 2010 Wiley Periodicals, Inc. Concepts Magn Reson Part A 36A: 243,254, 2010. [source]


    Clock synchronization in Cell/B.E. traces

    CONCURRENCY AND COMPUTATION: PRACTICE & EXPERIENCE, Issue 14 2009
    M. Biberstein
    Abstract Cell/B.E. is a heterogeneous multicore processor that was designed for the efficient execution of parallel and vectorizable applications with high computation and memory requirements. The transition to multicores introduces the challenge of providing tools that help programmers tune the code running on these architectures. Tracing tools, in particular, often help locate performance problems related to thread and process communication. A major impediment to implementing tracing on Cell is the absence of a common clock that can be accessed at low cost from all cores. The OS clock is costly to access from the auxiliary cores and the hardware timers cannot be simultaneously set on all the cores. In this paper, we describe an offline trace analysis algorithm that assigns wall-clock time to trace records based on their thread-local time stamps and event order. Our experiments on several Cell SDK workloads show that the indeterminism in assigning wall-clock time to events is low, on average 20,40 clock ticks (translating into 1.4,2.8,µs on the system used in our experiments). We also show how various practical problems, such as the imprecision of time measurement, can be overcome. Copyright © 2009 John Wiley & Sons, Ltd. [source]


    Network-aware selective job checkpoint and migration to enhance co-allocation in multi-cluster systems,

    CONCURRENCY AND COMPUTATION: PRACTICE & EXPERIENCE, Issue 13 2009
    William M. Jones
    Abstract Multi-site parallel job schedulers can improve average job turn-around time by making use of fragmented node resources available throughout the grid. By mapping jobs across potentially many clusters, jobs that would otherwise wait in the queue for local resources can begin execution much earlier; thereby improving system utilization and reducing average queue waiting time. Recent research in this area of scheduling leverages user-provided estimates of job communication characteristics to more effectively partition the job across system resources. In this paper, we address the impact of inaccuracies in these estimates on system performance and show that multi-site scheduling techniques benefit from these estimates, even in the presence of considerable inaccuracy. While these results are encouraging, there are instances where these errors result in poor job scheduling decisions that cause network over-subscription. This situation can lead to significantly degraded application performance and turnaround time. Consequently, we explore the use of job checkpointing, termination, migration, and restart (CTMR) to selectively stop offending jobs to alleviate network congestion and subsequently restart them when (and where) sufficient network resources are available. We then characterize the conditions and the extent to which the process of CTMR improves overall performance. We demonstrate that this technique is beneficial even when the overhead of doing so is costly. Copyright © 2009 John Wiley & Sons, Ltd. [source]


    Current Technique of Fluid Status Assessment

    CONGESTIVE HEART FAILURE, Issue 2010
    FACEP, W. Frank Peacock MD
    Congest Heart Fail. 2010;16(4)(suppl 1):S45,S51. ©2010 Wiley Periodicals, Inc. Early in the management of acute illness, it is critically important that volume status is accurately estimated. If inappropriate therapy is given because of errors in volume assessment, acute mortality rates are increased. Unfortunately, as the gold standard of radioisotopic volume measurement is costly and time-consuming, in the acute care environment clinicians are forced to rely on less accurate measures. In this manuscript, the authors review the currently available techniques of volume assessment for patients presenting with acute illness. In addition to discussing the accuracy of the history, physical examination, and radiography, acoustic cardiography and bedside ultrasonography are presented. [source]


    Comparison of Impedance Cardiography to Direct Fick and Thermodilution Cardiac Output Determination in Pulmonary Arterial Hypertension

    CONGESTIVE HEART FAILURE, Issue 2004
    Gordon L. Yung MD
    Cardiac output (CO) is an important diagnostic and prognostic tool for patients with ventricular dysfunction. Pulmonary hypertension patients undergo invasive right heart catheterization to determine pulmonary vascular and cardiac hemodynamics. Thermodilution (TD) and direct Fick method are the most common methods of CO determination but are costly and may be associated with complications. The latest generation of impedance cardiography (ICG) provides noninvasive estimation of CO and is now validated. The purpose of this study was to compare ICG measurement of CO to TD and direct Fick in pulmonary hypertension patients. Thirty-nine enrolled patients were analyzed: 44% were male and average age was 50.8±17.4 years. Results for bias and precision of cardiac index were as follows: ICG vs. Fick (,0.13 L/min/m2 and 0.46 L/min/m2), TD vs. Fick (0.10 L/min/m2 and 0.41 L/min/m2), ICG vs. TD (respectively, with a 95% level of agreement between ,0.72 and 0.92 L/min/m2; CO correlation of ICG vs. Fick, TD vs. Fick, and ICG vs. TD was 0.84, 0.89, and 0.80, respectively). ICG provides an accurate, useful, and cost-effective method for determining CO in pulmonary hypertension patients, and is a potential tool for following responses to therapeutic interventions. [source]


    Comparative Overview of Cardiac Output Measurement Methods: Has Impedance Cardiography Come of Age?

    CONGESTIVE HEART FAILURE, Issue 2 2000
    Anthony N. De Maria MD
    Cardiac output, usually expressed as liters of blood ejected by the left ventricle per minute, is a fundamental measure of the adequacy of myocardial function to meet the perfusion needs of tissue at any time. Decreases in cardiac output over time (when cardiac output is measured under similar conditions) may signal myocardial functional deterioration and the onset or progression of heart failure. Conversely, improvements in cardiac output may indicate a positive response to medical therapy. However, most methods for evaluating cardiac output are technically demanding, require specialized training and specialized environments for measurement, and are costly. Therefore, most measurement techniques are impractical for routine evaluation of disease progression and/or response to treatment in the prevention and/or management of heart failure. This paper provides a comparative overview of commonly employed cardiac output measurement strategies with emphasis on developments in impedance cardiography which suggest that impedance cardiography has the potential to make routine assessment and trending of cardiac output a viable alternative to assist in the management of both chronically and acutely ill patients, including those with heart failure. [source]


    Confronting Uncertainty and Missing Values in Environmental Value Transfer as Applied to Species Conservation

    CONSERVATION BIOLOGY, Issue 5 2010
    SONIA AKTER
    conservación de especies; error de transferencia; incertidumbre; transferencia de valor ambiental; valores de no uso Abstract:,The nonuse (or passive) value of nature is important but time-consuming and costly to quantify with direct surveys. In the absence of estimates of these values, there will likely be less investment in conservation actions that generate substantial nonuse benefits, such as conservation of native species. To help overcome decisions about the allocation of conservation dollars that reflect the lack of estimates of nonuse values, these values can be estimated indirectly by environmental value transfer (EVT). EVT uses existing data or information from a study site such that the estimated monetary value of an environmental good is transferred to another location or policy site. A major challenge in the use of EVT is the uncertainty about the sign and size of the error (i.e., the percentage by which transferred value exceeds the actual value) that results from transferring direct estimates of nonuse values from a study to a policy site, the site where the value is transferred. An EVT is most useful if the decision-making framework does not require highly accurate information and when the conservation decision is constrained by time and financial resources. To account for uncertainty in the decision-making process, a decision heuristic that guides the decision process and illustrates the possible decision branches, can be followed. To account for the uncertainty associated with the transfer of values from one site to another, we developed a risk and simulation approach that uses Monte Carlo simulations to evaluate the net benefits of conservation investments and takes into account different possible distributions of transfer error. This method does not reduce transfer error, but it provides a way to account for the effect of transfer error in conservation decision making. Our risk and simulation approach and decision-based framework on when to use EVT offer better-informed decision making in conservation. Resumen:,El valor de no uso (o pasivo) de la naturaleza es importante pero su cuantificación con muestreos pasivos consume tiempo y es costosa. En ausencia de estimaciones de estos valores, es probable que haya menos inversión en acciones de conservación que generen beneficios de no uso sustanciales, tal como la conservación de especies nativas. Para ayudar a superar decisiones respecto a la asignación de dólares para conservación que reflejan la carencia de estimaciones de los valores de no uso, estos valores pueden ser estimados indirectamente por la transferencia de valor ambiental (TVA). La transferencia de valor ambiental utiliza datos existentes o información de un sitio de estudio de tal manera que el valor monetario estimado de un bien ambiental es transferido a otro sitio. Un reto mayor en el uso de TVA es la incertidumbre sobre la señal y el tamaño del error (i.e., el porcentaje en que el valor transferido excede al valor actual) que resulta de la transferencia de estimaciones directas de los valores de no uso de un sitio de estudio a uno político, el sitio adonde el valor es transferido. Una TVA es más útil si el marco de toma de decisiones no requiere información muy precisa y cuando la decisión de conservación está restringida por tiempo y recursos financieros. Para tomar en cuenta la incertidumbre en el proceso de toma de decisiones, se puede seguir una decisión heurística que guie el proceso de decisión e ilustre sobre las posibles ramificaciones de la decisión. Para tomar en cuenta la incertidumbre asociada con la transferencia de valores de un sitio a otro, desarrollamos un método de riesgo y simulación que utiliza simulaciones Monte Carlo para evaluar los beneficios netos de las inversiones de conservación y que considera posibles distribuciones diferentes de la transferencia de error. Este método no reduce el error de transferencia, pero proporciona una manera para considerar el efecto del error de transferencia en la toma de decisiones de conservación. Nuestro método de riesgo y simulación y el marco de referencia basado en decisones sobre cuando utilizar TVA permiten la toma de decisiones en conservación más informadas. [source]


    Why bartering biodiversity fails

    CONSERVATION LETTERS, Issue 4 2009
    Susan Walker
    Abstract Regulatory biodiversity trading (or biodiversity "offsets") is increasingly promoted as a way to enable both conservation and development while achieving "no net loss" or even "net gain" in biodiversity, but to date has facilitated development while perpetuating biodiversity loss. Ecologists seeking improved biodiversity outcomes are developing better assessment tools and recommending more rigorous restrictions and enforcement. We explain why such recommendations overlook and cannot correct key causes of failure to protect biodiversity. Viable trading requires simple, measurable, and interchangeable commodities, but the currencies, restrictions, and oversight needed to protect complex, difficult-to-measure, and noninterchangeable resources like biodiversity are costly and intractable. These safeguards compromise trading viability and benefit neither traders nor regulatory officials. Political theory predicts that (1) biodiversity protection interests will fail to counter motivations for officials to resist and relax safeguards to facilitate exchanges and resource development at cost to biodiversity, and (2) trading is more vulnerable than pure administrative mechanisms to institutional dynamics that undermine environmental protection. Delivery of no net loss or net gain through biodiversity trading is thus administratively improbable and technically unrealistic. Their proliferation without credible solutions suggests biodiversity offset programs are successful "symbolic policies," potentially obscuring biodiversity loss and dissipating impetus for action. [source]


    Production Efficiency and the Pricing of Audit Services,

    CONTEMPORARY ACCOUNTING RESEARCH, Issue 1 2003
    Nicholas Dopuch
    Abstract In this paper, we examine the relative efficiency of audit production by one of the then Big 6 public accounting firms for a sample of 247 geographically dispersed audits of U.S. companies performed in 1989. To test the relative efficiency of audit production, we use both stochastic frontier estimation (SFE) and data envelopment analysis (DEA). A feature of our research is that we also test whether any apparent inefficiencies in production, identified using SFE and DEA, are correlated with audit pricing. That is, do apparent inefficiencies cause the public accounting firm to reduce its unit price (billing rate) per hour of labor utilized on an engagement? With respect to results, we do not find any evidence of relative (within-sample) inefficiencies in the use of partner, manager, senior, or staff labor hours using SFE. This suggests that the SFE model may not be sufficiently powerful to detect inefficiencies, even with our reasonably large sample size. However, we do find apparent inefficiencies using the DEA model. Audits range from about 74 percent to 100 percent relative efficiency in production, while the average audit is produced at about an 88 percent efficiency level, relative to the most efficient audits in the sample. Moreover, the inefficiencies identified using DEA are correlated with the firm's realization rate. That is, average billing rates per hour fall as the amount of inefficiency increases. Our results suggest that there are moderate inefficiencies in the production of many of the subject public accounting firm's audits, and that such inefficiencies are economically costly to the firm. [source]


    Towards a New Logic for Front End Management: From Drug Discovery to Drug Design in Pharmaceutical R&D

    CREATIVITY AND INNOVATION MANAGEMENT, Issue 2 2007
    Maria Elmquist
    Under pressure to innovate and be cost-effective at the same time, R&D departments are being challenged to develop new organizations and processes for Front End activities. This is especially true in the pharmaceutical industry. As drug development becomes more risky and costly, the discovery departments of pharmaceutical companies are increasingly being compelled to provide strong drug candidates for efficient development processes and quick market launches. It is argued that the Fuzzy Front End consists less of the discovery or recognition of opportunities than of the building of expanded concepts: the notion of concept generation is revisited, suggesting the need for a new logic for organizing Front End activities in order to support sustainable innovative product development. Based on an in-depth empirical study at a European pharmaceutical company, this paper contributes to improved understanding of the actual management practices used in the Front End. Using a design reasoning model (the C-K model), it also adds to the growing body of literature on the management of Front End activities in new product development processes. [source]


    Managing Interdependence: The Effects of Outsourcing Structure on the Performance of Complex Projects,

    DECISION SCIENCES, Issue 1 2008
    Pamsy P. Hui
    ABSTRACT The outsourcing of complex activities has become a common organizational practice. Yet very little research has focused on the implications of how these activities are divided up among outsourcing partners. Drawing on structural contingency theory, we argue that: (1) because activities within stages of complex projects are highly interdependent, outsourcing structures where owner firms do not maintain high levels of dominance over the activities that are performed will pose control and coordination challenges, leading to poor project performance; (2) the adverse effects of poorly structured outsourcing arrangements will spill over to subsequent project stages when activities are interdependent across project stages; and (3) dividing activities among large numbers of contractors or distributing work evenly among contractors exacerbates coordination and control problems further contributing to poor project performance. Our empirical analysis of 323 capital facility construction projects supports our predictions. Overall, these results provide strong evidence that some outsourcing structures are more costly than others and that because of the nature of complex projects the detrimental effects of poorly structured outsourcing are often not completely observable at the time activities are completed. We discuss the implications of our findings for capital construction and for outsourcing more generally. [source]


    Absent and Accounted For: Absenteeism and Cooperative Learning,

    DECISION SCIENCES JOURNAL OF INNOVATIVE EDUCATION, Issue 1 2006
    G. D. Koppenhaver
    ABSTRACT In a small section collaborative learning environment where student work teams promote mutual learning about investments, students limit the opportunity to learn from other students if they are absent from class. Absenteeism not only denies the student the opportunity to learn from others but also denies other members of the student's work team the opportunity to learn from the absent student. Other team members' absenteeism should be costly for individual performance if collaborative learning fosters learning and retention. The research finds that while absenteeism is detrimental to the student's own performance, absenteeism of other team members from team activities has a significant negative effect on both individual exam and homework scores. The conclusions validate the benefits of active learning and of encouraging attendance in collaborative learning environments in all disciplines. [source]


    Conceptual background, development, and preliminary data from the unified protocol for transdiagnostic treatment of emotional disorders,

    DEPRESSION AND ANXIETY, Issue 10 2010
    Zofia A. Wilamowska M.A.
    Abstract Anxiety and mood disorders are common, chronic, costly, and characterized by high comorbidity. The development of cognitive behavioral approaches to treating anxiety and mood disorders has left us with highly efficacious treatments that are increasingly widely accepted. The proliferation of treatment manuals targeting single disorders, sometimes with trivial differences among them, leaves the mental health professional with no clear way to choose one manual over another and little chance of ever becoming familiar with most of them, let alone trained to competence in their delivery. Deepening understanding of the nature of emotional disorders reveals that commonalities in etiology and latent structures among these disorders supersedes differences. Based on empirical evidence from the domains of learning, emotional development and regulation, and cognitive science, we have distilled a set of psychological procedures that comprise a unified intervention for emotional disorders. The Unified Protocol (UP) is a transdiagnostic, emotion-focused cognitive behavioral treatment, which emphasizes the adaptive, functional nature of emotions, and seeks to identify and correct maladaptive attempts to regulate emotional experiences, thereby facilitating appropriate processing and extinction of excessive emotional responding to both internal (somatic) and external cues. The treatment components of the UP are briefly outlined. Theory and rationale supporting this new approach are described along with some preliminary evidence supporting its efficacy. Implications for the treatment of emotional disorders using the UP are discussed. Depression and Anxiety, 2010. © 2010 Wiley-Liss, Inc. [source]


    Cardiac anxiety in people with and without coronary atherosclerosis,

    DEPRESSION AND ANXIETY, Issue 10 2008
    Craig D. Marker Ph.D.
    Abstract Many studies have shown that cardiac anxiety when occurring in the absence of coronary artery disease is common and quite costly. The Cardiac Anxiety Questionnaire (CAQ) is an 18-item self-report measure that assesses anxiety related to cardiac symptoms. To better understand the construct of cardiac anxiety, a factor analysis was conducted on CAQ data from 658 individuals who were self or physician-referred for electron beam tomographic screening to determine whether clinically significant coronary atherosclerosis was present. A four-factor solution was judged to provide the best fit with the results reflecting the following factor composition: heart-focused attention, avoidance of activities that bring on symptoms, worry or fear regarding symptoms, and reassurance-seeking. Factorial invariance across groups was also assessed to determine whether the factor structure of the CAQ was similar in individuals with and without clear evidence of coronary atherosclerosis. The factor structure of the CAQ did not differ between the two groups. However, the group without coronary atherosclerosis had significantly higher mean scores on their attention and worry/fear factors suggesting that people without a diagnosed cardiac condition pay more attention to and worry more about their cardiac-related symptoms than those people who have coronary atherosclerosis. Depression and Anxiety 2007. Published 2007 Wiley-Liss, Inc. [source]


    A Simple, Pain-Free Treatment for Ingrown Toenails Complicated with Granulation Tissue

    DERMATOLOGIC SURGERY, Issue 11 2006
    F. GÜLRU ERDOGAN MD
    BACKGROUND The treatment of ingrown toenail complicated with granulation tissue is usually partial or total nail avulsion with or without matricectomy. It costs loss of occupational power, however, because most patients cannot go to work or school for some time after surgery, and it is a costly and uncomfortable procedure for most patients. OBJECTIVE This study aimed to find an easy, painless, and inexpensive alternative. MATERIALS AND METHODS Seven patients with ingrown toenails complicated with granulation tissue are included. A small apparatus was applied on the nails, granulation tissue was chemically cauterized, and a foot bath was recommended twice daily. They were followed on a weekly basis or every other week until recovery. None of the patients received systemic treatment. RESULTS All seven patients were completely cured without requiring surgery and/or systemic treatment. The procedure did not have any effect on their daily life. The follow-up examination of the patients at 6 months revealed that they were totally cured, and there were no recurrences. CONCLUSION Patients with ingrown toenails complicated by granulation tissue might have an inexpensive and pain-free treatment alternative, although new studies with more patients are required. [source]


    Psychoeducational intervention for caregivers of Indian patients with schizophrenia: a randomised-controlled trial

    ACTA PSYCHIATRICA SCANDINAVICA, Issue 6 2009
    P. Kulhara
    Objective:, There are hardly any randomised-controlled trials of structured family interventions for schizophrenia from India. This study attempted to evaluate the impact of a structured psychoeducational intervention for schizophrenia, compared with standard out-patient treatment, on various patient- and caregiver-related parameters. Method:, Seventy-six patients with DSM-IV schizophrenia and their caregivers were randomly allocated to receive either a structured psychoeducational intervention (n = 38) consisting of monthly sessions for 9 months or ,routine' out-patient care (n = 38) for the same duration. Psychopathology was assessed on monthly basis. Disability levels, caregiver-burden, caregiver-coping, caregiver-support and caregiver-satisfaction were evaluated at baseline and upon completion. Results:, Structured psychoeducational intervention was significantly better than routine out-patient care on several indices including psychopathology, disability, caregiver-support and caregiver-satisfaction. The psychoeducational intervention package used was simple, feasible and not costly. Conclusion:, Structured psychoeducational intervention is a viable option for treatment of schizophrenia even in developing countries like India. [source]


    Nipple preference and contests in suckling kittens of the domestic cat are unrelated to presumed nipple quality

    DEVELOPMENTAL PSYCHOBIOLOGY, Issue 4 2009
    Robyn Hudson
    Abstract We studied the development of suckling behavior and weight gain in 11 litters (52 kittens) of free-ranging domestic cats until postnatal day 28 just before the start of weaning. In six of these litters, we also recorded milk intake and contests for access to nipples. Already within 12 hr of birth kittens showed a preference for posterior nipples, and by postnatal day 3 each had developed a preference for particular nipples. In fact, 86% of kittens used one particular nipple most often, and even when the mother changed the side she lay on to nurse. Contests for access to nipples occurred throughout the study period at an average rate of one to two contests per kitten per hour of nursing. Contrary to suggestions in the literature that kittens compete for more productive nipples, we found no relation between kittens' use of particular nipples and their weight gain, milk intake, or involvement in contests during suckling. We suggest that kittens' preference for posterior nipples as well as their establishment of an individual "teat order" might function to optimize the number of nipples remaining productive across lactation, and to reduce energetically costly scrambles and potentially injurious contests among littermates. © 2009 Wiley Periodicals, Inc. Dev. Psychobiol 51: 322,332, 2009. [source]


    A cost-effectiveness analysis of four management strategies in the determination and follow-up of atypical squamous cells of undetermined significance

    DIAGNOSTIC CYTOPATHOLOGY, Issue 2 2005
    Alice A. Hughes M.S.P.H.
    Abstract Atypical squamous cells of undetermined significance (ASC-US) are the most common abnormal cytological result on Papanicolaou (Pap) smear. We analyzed four management strategies in a hypothetical cohort of women divided by age group: (1) immediate colposcopy, (2) repeat cytology after an ASC-US Pap smear result, (3) conventional Pap with reflex human papillomavirus (HPV) testing, and (4) liquid-based cytology with reflex HPV testing. Parameter variables were collected from previously published data. Strategies that included reflex HPV testing had the lowest overall costs for all age groups combined. Repeat Pap smears had the highest number of true positive results throughout all stages but also had the uppermost number of missed cancers and highest costs. Immediate colposcopy had the second highest overall costs and detected fewer true positive results than liquid-based cytology. Younger women (aged 18,24 yr) consistently had higher total costs for all strategies investigated. Using the incremental cost-effectiveness (CE) ratio, the immediate colposcopy strategy was more costly and less effective than liquid-based cytology and, therefore, was dominated. The incremental CE ratio was lowest for liquid-based cytology compared with conventional cytology and liquid-based cytology with reflex HPV testing was the most cost-effective strategy. Diagn. Cytopathol. 2005;32:125,132. © 2005 Wiley-Liss, Inc. [source]


    A Stark Examination of Prison Culture and Prison Ministry

    DIALOG, Issue 3 2008
    R.N. Ristad
    Abstract:, This article offers an insightful examination of prison ministry from the inside, from someone who has been involved with this ministry for over forty-five years. The author discusses four major issues that are particularly costly, both in terms of personal human costs and also financial costs. First, society's misconceptions about prison violence, and the complex, varied ways prisoners experience violence. Second, the false sense of security the current practices of institutionalization create, and the consequences they have on the inmates. Third, the risk factors that can predispose children to ending up in prison, and the lack of care and attention those children often receive. And fourth, the way in which the criminalization of drug abuse has exacerbated many problems with the current prison system. The author concludes his article with some suggestions for reforming the prison system. [source]


    Unauthorised development and seismic hazard vulnerability: a study of squatters and engineers in Istanbul, Turkey

    DISASTERS, Issue 3 2008
    Rebekah A. Green
    Many cities in developing nations have experienced an influx of poor migrants in search of work. This population influx has often been accommodated through land squatting, irregular construction and unauthorised housing. For the urban poor, this has resulted in immediate affordable housing; however, this housing frequently has long-term vulnerability to natural hazards. This article examines the ways in which squatters in Istanbul, Turkey, understand the seismic vulnerability of their unauthorised housing. Distrust of professional engineers and contractors has led Istanbul squatters to believe that self-built housing will not only be less costly but also safer than commercially built housing. The impact of residents' risk perceptions on their vulnerability to natural hazards is examined through a comparison of social attitudes regarding safe housing and the quality of unauthorised construction. This comparison highlights how squatters' risk perceptions necessitate innovative means of reducing vulnerability in unauthorised neighbourhoods of developing cities. [source]


    Aerial photosieving of exposed gravel bars for the rapid calibration of airborne grain size maps

    EARTH SURFACE PROCESSES AND LANDFORMS, Issue 6 2010
    Stephen J. Dugdale
    Abstract In recent years, fluvial remote sensing has seen considerable progress in terms of methods capable of system scale characterisation of river catchments. One key development is automated grain size mapping. It has been shown that high resolution aerial photography can be used to automatically produce grain size maps over entire rivers. However, current aerial grain size mapping procedures all require field calibration data. The collection of such data can be costly and problematic in the case of remote areas. This paper presents a method developed to remove the need for field based calibration data. Called ,aerial photosieving', this method consists of using the same very high resolution aerial imagery intended for grain size map production to visually measure particle sizes on-screen in order to provide calibration data. The paper presents a rigorous comparison of field-based photosieving calibration data and aerial photosieving calibration data. Statistical tests are used to demonstrate that aerial photosieving gives similar results when compared with field-based data with only a slight systematic overprediction. The new aerial photosieving method therefore simplifies the overall procedure required for the production of grain size maps and thus improves the cost-effectiveness and potential availability of this new fluvial remote sensing technology. Copyright © 2010 John Wiley &Sons, Ltd. [source]


    A geomatics data integration technique for coastal change monitoring

    EARTH SURFACE PROCESSES AND LANDFORMS, Issue 6 2005
    J. P. Mills
    Abstract This paper reports research carried out to develop a novel method of monitoring coastal change, using an approach based on digital elevation models (DEMs). In recent years change monitoring has become an increasingly important issue, particularly for landforms and areas that are potentially hazardous to human life and assets. The coastal zone is currently a sensitive policy area for those involved with its management, as phenomena such as erosion and landslides affect the stability of both the natural and the built environment. With legal and financial implications of failing to predict and react to such geomorphological change, the provision of accurate and effective monitoring is essential. Long coastlines and dynamic processes make the application of traditional surveying difficult, but recent advances made in the geomatics discipline allow for more effective methodologies to be investigated. A solution is presented, based on two component technologies , the Global Positioning System (GPS) and digital small format aerial photogrammetry , using data fusion to elim-inate the disadvantages associated with each technique individually. A sparse but highly accurate DEM, created using kinematic GPS, was used as control to orientate surfaces derived from the relative orientation stage of photogrammetric processing. A least squares surface matching algorithm was developed to perform the orientation, reducing the need for costly and inefficient ground control point survey. Change detection was then carried out between temporal data epochs for a rapidly eroding coastline (Filey Bay, North Yorkshire). The surface matching algorithm was employed to register the datasets and determine dif-ferences between the DEM series. Large areas of change were identified during the lifetime of the study. Results of this methodology were encouraging, the flexibility, redundancy and automation potential allowing an efficient approach to landform monitoring. Copyright © 2005 John Wiley & Sons, Ltd. [source]


    Ambient ultraviolet-B radiation reduces hatchling size in the common frog Rana temporaria

    ECOGRAPHY, Issue 5 2000
    Maarit Pahkala
    Effects of ambient UV-B radiation and pH on hatchability and early development of Rana temporaria embryos were studied in field experiments conducted at two sites in Sweden. In neither of the populations did we find clear evidence for reduced hatchability or increased frequency of developmental anomalies of embryos exposed to ambient UV-B levels. However, in both populations hatchling size was significantly larger UV-B blocked as compared to control treatments, suggesting that ambient UV-B levels had a negative effect on early growth of embryos. This result is consistent with the hypothesis that the cellular UV-B damage repair mechanisms are costly and trades-off against early growth. Alternatively, UV-B induced photoproducts inhibiting DNA-transcription and thereby protein synthesis may directly reduce growth rate. Although low pH (5.0) had negative effects on hatchability and early embryonic growth, there was no evidence for synergistic effects of pH and UV-B on hatchability, frequency of developmental anomalies or early growth. The results suggest that increased levels of UV-B radiation may cause fitness loss in natural populations of the common frog. [source]


    Costs of cannibalism in the presence of an iridovirus pathogen of Spodoptera frugiperda

    ECOLOGICAL ENTOMOLOGY, Issue 2 2006
    Trevor Williams
    Abstract., 1.,The costs of cannibalism were examined in larvae of Spodoptera frugiperda (J. E. Smith) (Lepidoptera: Noctuidae) in the presence of conspecifics infected by a lethal invertebrate iridescent virus (IIV). The hypothesis of a positive correlation between insect density and the likelihood of disease transmission by cannibalism was examined in laboratory microcosms and a field experiment. 2.,Transmission was negligible following peroral infection of early instars with purified virus suspensions or following coprophagy of virus-contaminated faeces excreted by infected insects. In contrast, 92% of the insects that predated infected conspecifics acquired the infection and died prior to adult emergence in the laboratory. Diseased larvae were more likely to be victims of cannibalism than healthy larvae. 3.,The prevalence of cannibalism was density dependent in laboratory microcosms with a low density (10 healthy insects + one infected insect) or high density (30 healthy insects + one infected insect) of insects, and field experiments performed on maize plants infested with one or four healthy insects + one infected insect. 4.,Cannibalism in the presence of virus-infected conspecifics was highly costly to S. frugiperda; in all cases, insect survival was reduced by between ,,50% (laboratory) and ,,30% (field) in the presence of the pathogen. Contrary to expectations, the prevalence of disease was not sensitive to density because cannibalism resulted in self-thinning. As infected individuals are consumed and disappear from the population, the prevalence of disease will be determined by the timescale over which transmission can be achieved, and the rate at which individuals that have acquired an infection become themselves infectious to conspecific predators. [source]


    Male field crickets that provide reproductive benefits to females incur higher costs

    ECOLOGICAL ENTOMOLOGY, Issue 3 2005
    William E. Wagner JR
    Abstract., 1.,Females often select mates based on signals correlated with the quality of the direct benefits that males will provide to them. A male's quality as a mate and the structure of his mating signals may covary because both traits are energetically expensive for males to produce and because both traits are affected by short-term changes in nutritional condition. 2.,In the variable field cricket, Gryllus lineaticeps, previous work has shown that females receive reproductive benefits from males that produce higher chirp rates and lifespan benefits from males that produce longer chirp durations, even when they only receive the sperm and seminal fluid contained in male spermatophores. Higher chirp rates are energetically expensive for males to produce, and chirp rate is strongly affected by diet quality, whereas longer chirp durations do not appear to be expensive for males to produce, and chirp duration does not appear to be affected by male diet quality. In this study two hypotheses were tested about the energetic costs of spermatophore production: (1) that spermatophores are expensive for males to produce and (2) that males providing greater direct benefits to females incur higher costs of spermatophore production. 3.,Males that were provided with a lower quality diet took longer to produce a new spermatophore. This result suggests that spermatophores are costly for males to produce. 4.,Males that produced higher chirp rates took longer to produce a new spermatophore. This result suggests that male chirp rate and female reproductive benefits may covary because both traits are energetically expensive for males to produce and thus are affected by male nutritional condition. There was no association, however, between male chirp duration and spermatophore production time. [source]


    Effect of soil hardness on aggression in the solitary wasp Mellinus arvensis

    ECOLOGICAL ENTOMOLOGY, Issue 5 2001
    Jaboury Ghazoul
    Summary 1. Two alternative nesting strategies are exhibited by soil-nesting Mellinus arvensis females, digging a new nest (diggers) and searching for an old unoccupied burrow (searchers). Wasps appear unable to distinguish between occupied and unoccupied nests, and aggressive interactions between searchers and nest owners at nest entrances are frequent. 2. In aggressive encounters, there is an advantage in size and residency status. 3. The costs associated with the two nesting strategies vary across geographically separated populations: nest digging incurs costs in terms of time, and these vary according to the hardness of the soil substrate; nest searching is variably costly in terms of risk of injury in aggressive encounters with nest-owning females. 4. Individual female wasps can switch between nesting strategies, and thus soil hardness, by affecting the cost of nest construction, affects the relative frequencies of the two nesting strategies within a population, favouring an increase in the searching strategy. This, in turn, affects the frequency and intensity of aggression between females at a nesting aggregation. 5. Female body size is correlated with soil hardness. As aggressive encounters are more frequent in sites with hard soil substrates, there is increased selective advantage in having large body size at these sites. 6. Body size is determined primarily by the availability of food resources during larval development, which is, to a degree, a function of the size of the adult female. There is a trade-off between provisioning a few cells with many provisions in each, leading to the development of few but large adults, as opposed to many cells with few provisions, leading to many small offspring. The relative advantage of these two provisioning strategies is, at least in part, a function of the hardness of the soil substrate. [source]


    The promise and the potential consequences of the global transport of mycorrhizal fungal inoculum

    ECOLOGY LETTERS, Issue 5 2006
    Mark W. Schwartz
    Abstract Advances in ecology during the past decade have led to a much more detailed understanding of the potential negative consequences of species' introductions. Moreover, recent studies of mycorrhizal symbionts have led to an increased knowledge of the potential utility of fungal inoculations in agricultural, horticultural and ecological management. The intentional movement of mycorrhizal fungal species is growing, but the concomitant potential for negative ecological consequences of invasions by mycorrhizal fungi is poorly understood. We assess the degree to which introductions of mycorrhizal fungi may lead to unintended negative, and potentially costly, consequences. Our purpose is to make recommendations regarding appropriate management guidelines and highlight top priority research needs. Given the difficulty in discerning invasive species problems associated with mycorrhizal inoculations, we recommend the following. First, careful assessment documenting the need for inoculation, and the likelihood of success, should be conducted prior to inoculation because inoculations are not universally beneficial. Second, invasive species problems are costly and often impossible to control by the time they are recognized. We recommend using local inoculum sources whenever possible. Third, non-sterile cultures of inoculum can result in the movement of saprobes and pathogens as well as mutualists. We recommend using material that has been produced through sterile culture when local inoculum is not available. Finally, life-history characteristics of inoculated fungi may provide general guidelines relative to the likelihood of establishment and spread. We recommend that, when using non-local fungi, managers choose fungal taxa that carry life-history traits that may minimize the likelihood of deleterious invasive species problems. Additional research is needed on the potential of mycorrhizal fungi to spread to non-target areas and cause ecological damage. [source]