Interesting Challenges (interesting + challenge)

Distribution by Scientific Domains


Selected Abstracts


Learning of foraging skills by fish

FISH AND FISHERIES, Issue 3 2003
Kevin Warburton
Abstract This chapter outlines the relationships between a number of key factors that influence learning and memory, and illustrates them by reference to studies on the foraging behaviour of fish. Learning can lead to significant improvements in foraging performance in only a few exposures, and at least some fish species are capable of adjusting their foraging strategy as patterns of patch profitability change. There is also evidence that the memory window for prey varies between fish species, and that this may be a function of environmental predictability. Convergence between behavioural ecology and comparative psychology offers promise in terms of developing more mechanistically realistic foraging models and explaining apparently ,suboptimal' patterns of behaviour. Foraging decisions involve the interplay between several distinct systems of learning and memory, including those that relate to habitat, food patches, prey types, conspecifics and predators. Fish biologists, therefore, face an interesting challenge in developing integrated accounts of fish foraging that explain how cognitive sophistication can help individual animals to deal with the complexity of the ecological context. [source]


The Puzzle of Museum Educational Practice: A Comment on Rounds and Falk

CURATOR THE MUSEUM JOURNAL, Issue 2 2006
Daniel Spock
The mandate that museums place education at the center of their public service role has had the effect of framing a new set of questions and,inevitably,problems. If museums have primary value to society as educational institutions, what kind of learning actually happens in them? Jay Rounds and John Falk, writing at the leading edge of this inquiry, explore curiosity, motivation and self-identity as paramount considerations for the special type of learning museums promote. Their analyses present interesting challenges for the museum practitioner, who may observe that people find the pursuit of curiosity pleasurable and value it more highly than knowledge acquisition. The practitioner may conclude that museums have a calling: They stand for the value of curiosity for its own sake, and for that reason will never wear out their welcome. [source]


Adults with self-reported learning disabilities in Slovenia: Findings from the international adult literacy survey on the incidence and correlates of learning disabilities in Slovenia

DYSLEXIA, Issue 4 2003
Lidija Magajna
This study of adults with self-reported learning disabilities (SRLD) in Slovenia is part of a larger secondary analysis of the data from the International Literacy Survey project (IALS). The purpose of the study was to examine the characteristics of 79 (2.68%) individuals who reported experiencing learning disabilities and compare them to the general population on a variety of indicators of educational background, employment status, and reading and writing activities at work and at home. The proficiency scores of the SRLD individuals were lower in all three literacy domains (prose, document and quantitative literacy). In prose literacy 77.9% of SRLD adults performed at Level 1 and only 7.8% reached the level necessary for a modern technological society. Experiencing learning disabilities was not related to gender or age, however, results showed significant differences between the levels achieved by older and younger people with SRLD. In SRLD groups aged 40 years and above, no one achieved more than the second level of literacy in any domain. Learning disabilities were reported more frequently in rural areas. SRLD groups achieve significantly lower educational attainment, and lower employment status, with a preference for manual labour or craft. These findings are of critical importance. SRLD people report that poorer literacy skills are an obstacle to their progression in employment. In the Slovene sample, the SRLD group stands out for low scores in quantitative literacy. Results show that they are less active, pick up information only auditorily or in short written form. They need more frequent help from relatives in literacy activities. Interpretation of the IALS data on SRLD presents many problems. These include amongst others, problems in terminology, different background factors, and the validity of self-report measures. However, the study also raises many interesting challenges for future research and policy. Increasing the availability of support, assistance and counselling for adolescents and adults with learning disabilities remains a very important goal for dyslexia and LD policies in Slovenia. Copyright © 2003 John Wiley & Sons, Ltd. [source]


The Competitive Foundations of Localized Learning and Innovation: The Case of Women's Garment Production in New York City,

ECONOMIC GEOGRAPHY, Issue 4 2002
Norma M. Rantisi
Abstract: This article considers the relevance of the "local" for firm learning in New York City's Garment District. By documenting the design innovation process in the district's women's wear industry and the ways in which designers draw on the district's specialized services and institutions to assist in the process, the article examines how a localized agglomeration or "cluster" facilitates the development of shared conventions and practices. It also shows how the district confers benefits on firms in indirect ways. Since apparel manufacturers operate in a U.S. regulatory framework that inhibits cooperation, the Garment District's support institutions serve as production intermediaries, providing firms with a means to monitor and observe rival firms' performances and solutions. As such, the case of the Garment District poses interesting challenges to the prevailing conceptions of the "local" as a site for cooperation and suggests the need to rethink the relevance of competition for learning and innovation. [source]


Quantum monte carlo methods for electronic structure of nanosystems

ISRAEL JOURNAL OF CHEMISTRY, Issue 2-3 2002
Lubos Mitas
We provide a brief review of recent applications of quantum Monte Carlo (QMC) methods to the electronic structure of nanosystems. We report on calculations of carbon rings with second-order Jahn-Teller effect, energy ordering of silicon clusters, dissociation enthalpies of protonated hydrogen clusters, and other interesting challenges. We point out the QMC accuracy and outline a few ideas that characterize the current position of QMC among the electronic structure methods and its future development. [source]


Depression in paediatric cancer: an overview

PSYCHO-ONCOLOGY, Issue 7 2006
Margaret DeJong
Abstract Research into depression in paediatric cancer is in its early stages, but nevertheless has presented interesting challenges regarding the recognition and measurement of depression in a medically ill population. In this article we discuss the complex interaction between physical and psychological variables, and the diagnostic difficulties arising from this. We review the epidemiological findings regarding prevalence, evaluating the apparently low prevalence rate in the light of methodological weaknesses. Hypotheses put forward to explain the findings are discussed. We conclude by highlighting areas for future research. Copyright © 2005 John Wiley & Sons, Ltd. [source]


Seamless mobility across IMS and legacy circuit networks

BELL LABS TECHNICAL JOURNAL, Issue 4 2006
Maria R. G. Azada
The growing desire of network providers to introduce support for voice over IP (VoIP) has created interesting challenges in the area of interoperability with existing wireless circuit networks. The 3rd Generation Partnership Project (3GPP) and the 3rd Generation Partnership Project 2 (3GPP2) standards have defined the IP Multimedia Subsystem (IMS) as the platform for convergence. By definition, IMS is access agnostic; it provides services and features through a common core network, regardless of the means of transport. However, the IMS standards are just beginning to address the challenges associated with interworking with existing cellular circuit networks. Achieving seamless mobility involves supporting both roaming and handoff between networks. This paper discusses the issues involved in providing seamless mobility for subscribers across the packet and circuit domains and proposes network-based solutions. © 2006 Lucent Technologies Inc. [source]


Growth inhibition of dinoflagellate algae in shake flasks: Not due to shear this time!

BIOTECHNOLOGY PROGRESS, Issue 1 2010
Weiwei Hu
Abstract Large scale algae cultures present interesting challenges in that they exhibit characteristics of typical bacterial and animal cell cultures. One current commercial food additive, docosahexaenoic acid (DHA), is produced using the dinoflagellate algae, Crypthecodiniumcohnii. Like animal cell culture, the perceived sensitivity of algae culture to hydrodynamic forces has potentially limited the agitation and aeration applied to these systems. However, the high density cultivation of C. cohnii required for an economically feasible process inevitably results in high oxygen demand. In this study, we demonstrated what first appeared to be a problem with shear sensitivity in shake flasks is most probably a mass transfer limitation. We subsequently demonstrated the limit of chronic and rapid energy dissipation rate, EDR, that C. cohnii cells can experience. This limit was determined using a microfluidic device connected in a recirculation loop to a stirred tank bioreactor, which has been previously used to repeatedly expose animal cells to high levels of EDR. Inhibition of cell growth was observed when C. cohnii cells were subjected to an EDR of 5.9 × 106 W/m3 with an average frequency of 0.2/min or more. This level of EDR is sufficiently high that C. cohnii can withstand typically encountered hydrodynamic forces in bioprocesses. This result suggests that at least one dinoflagellate algae, C. cohnii, is quite robust with respect to hydrodynamic forces and the scale-up of process using this type of algae should be more concerned with providing sufficient gas transfer given the relatively high oxygen demand. © 2009 American Institute of Chemical Engineers Biotechnol. Prog., 2010 [source]


Selenium- and Tellurium-Containing Multifunctional Redox Agents as Biochemical Redox Modulators with Selective Cytotoxicity

CHEMISTRY - A EUROPEAN JOURNAL, Issue 36 2010
Dr. Vincent Jamier
Abstract Various human diseases, including different types of cancer, are associated with a disturbed intracellular redox balance and oxidative stress (OS). The past decade has witnessed the emergence of redox-modulating compounds able to utilize such pre-existing disturbances in the redox state of sick cells for therapeutic advantage. Selenium- and tellurium-based agents turn the oxidizing redox environment present in certain cancer cells into a lethal cocktail of reactive species that push these cells over a critical redox threshold and ultimately kill them through apoptosis. This kind of toxicity is highly selective: normal, healthy cells remain largely unaffected, since changes to their naturally low levels of oxidizing species produce little effect. To further improve selectivity, multifunctional sensor/effector agents are now required that recognize the biochemical signature of OS in target cells. The synthesis of such compounds provides interesting challenges for chemistry in the future. [source]