bluuebunny/crossref_metadata_2025 huggingface dataset:
Discarte
Authors: Sherwood Rob , Bender Adam , Spring Neil
Published: August 2008

Internet topology discovery consists of inferring the inter-router connectivity ("links") and the mapping from IP addresses to routers ("alias resolution"). Current topology discovery techniques use TTL-limited "traceroute" probes to discover links and use direct router probing to resolve aliases. The often-ignored record route (RR) IP option provides a source of disparate topology data that could augment existing techniques, but it is difficult to properly align with traceroute-based topologies because router RR implementations are under-standardized. Correctly aligned RR and traceroute topologies have fewer false links, include anonymous and hidden routers, and discover aliases for routers that do not respond to direct probing. More accurate and feature-rich topologies benefit overlay construction and network diagnostics, modeling, and measurement.

We present DisCarte, a system for aligning and cross-validating RR and traceroute topology data using observed engineering practices DisCarte uses disjunctive logic programming (DLP), a logical inference and constraint solving technique, to intelligently merge RR and traceroute data. We demonstrate that the resultant topology is more accurate and complete than previous techniques by validating its internal consistency and by comparing to publicly-available topologies. We classify irregularities in router implementations and introduce a divide-and-conquer technique used to scale DLP to Internet-sized systems.
Accountable internet protocol (aip)
Authors: Andersen David G. , Balakrishnan Hari , Feamster Nick , Koponen Teemu , Moon Daekyeong , Shenker Scott
Published: August 2008

This paper presents AIP (Accountable Internet Protocol), a network architecture that provides accountability as a first-order property. AIP uses a hierarchy of self-certifying addresses, in which each component is derived from the public key of the corresponding entity. We discuss how AIP enables simple solutions to source spoofing, denial-of-service, route hijacking, and route forgery. We also discuss how AIP's design meets the challenges of scaling, key management, and traffic engineering.
Challenges, design and analysis of a large-scale p2p-vod system
Authors: Huang Yan , Fu Tom Z.J. , Chiu Dah-Ming , Lui John C.S. , Huang Cheng
Published: August 2008

P2P file downloading and streaming have already become very popular Internet applications. These systems dramatically reduce the server loading, and provide a platform for scalable content distribution, as long as there is interest for the content. P2P-based video-on-demand (P2P-VoD) is a new challenge for the P2P technology. Unlike streaming live content, P2P-VoD has less synchrony in the users sharing video content, therefore it is much more difficult to alleviate the server loading and at the same time maintaining the streaming performance. To compensate, a small storage is contributed by every peer, and new mechanisms for coordinating content replication, content discovery, and peer scheduling are carefully designed. In this paper, we describe and discuss the challenges and the architectural design issues of a large-scale P2P-VoD system based on the experiences of a real system deployed by PPLive. The system is also designed and instrumented with monitoring capability to measure both system and component specific performance metrics (for design improvements) as well as user satisfaction. After analyzing a large amount of collected data, we present a number of results on user behavior, various system performance metrics, including user satisfaction, and discuss what we observe based on the system design. The study of a real life system provides valuable insights for the future development of P2P-VoD technology.
Predictable performance optimization for wireless networks
Authors: Li Yi , Qiu Lili , Zhang Yin , Mahajan Ratul , Rozner Eric
Published: August 2008

We present a novel approach to optimize the performance of IEEE 802.11-based multi-hop wireless networks. A unique feature of our approach is that it enables an accurate prediction of the resulting throughput of individual flows. At its heart lies a simple yet model of the network that captures interference, traffic, and MAC-induced dependencies. Unless properly accounted for, these dependencies lead to unpredictable behaviors. For instance, we show that even a simple network of two links with one flow is vulnerable to severe performance degradation. We design algorithms that build on this model to optimize the network for fairness and throughput. Given traffic demands as input, these algorithms compute rates at which individual flows must send to meet the objective. Evaluation using a multi-hop wireless testbed as well as simulations show that our approach is very effective. When optimizing for fairness, our methods result in close to perfect fairness. When optimizing for throughput, they lead to 100-200% improvement for UDP traffic and 10-50% for TCP traffic.
A New Look at Global Forest Histories of Land Clearing
Authors: Williams Michael
Published: August 2008

Uncertainty about historical evidence of forest clearing is highlighted; nevertheless, its longevity and basic importance for survival make an understanding of the process important. First, archaeological and paleobotanical evidence for clearing during late Mesolithic and Neolithic Europe is examined. A similar examination of the Americas during past millennia emphasizes the myth of a pristine precontact forest. Post-1950s deforestation is beset with similar problems of forest extent and loss, pathways and processes of change, and the rate of change. Recent literature also reflects concerns about past and present motives in clearing and management, emphasizing conflicts between traditional users and modern producers, North/South inequalities of consumption/production, and social confrontation. The cultural meaning of the forest is another current theme, developed through dominant “discourses.” Finally, I argue that humans and the organic world are intimately entwined, and our expectations and ideas of the natural world actually mold the way we use and manipulate it.
Quorum Sensing in Staphylococci
Authors: Novick Richard P. , Geisinger Edward
Published: August 2008

The staphylococcal agr locus encodes a quorum sensing (QS) system that controls the expression of virulence and other accessory genes by a classical two-component signaling module. Like QS modalities in other Gram-positive bacteria, agr encodes an autoactivating peptide (AIP) that is the inducing ligand for AgrC, the agr signal receptor. Unlike other such systems, agr variants have arisen that show strong cross-inhibition in heterologous combinations, with important evolutionary implications. Also unlike other systems, the effector of global gene regulation in the agr system is a major regulatory RNA, RNAIII. In this review, we describe the functions of the agr system's elements, show how they interact to bring about the regulatory response, and discuss the role of QS in staphylococcal pathobiology. We conclude with the suggestion that agr autoactivation, unlike classical enzyme induction, can occur under suboptimal conditions and can distinguish self from non-self by inducing an exclusive and coordinated population wide response.
Undercover Policing and the Shifting Terms of Scholarly Debate: The United States and Europe in Counterpoint
Authors: Ross Jacqueline E.
Published: August 2008

Among investigative tactics, undercover policing is unique in the extent to which it allows the police to shape the events they investigate. Yet this shared feature of undercover investigations produces very different academic controversies in the United States and Europe. European scholars fear the implications of legalizing tactics that had previously been tolerated, if at all, at the margins of legality. By contrast, American commentators seek to unsettle what they view as complacency about a tactic that is used far more widely in the United States than in Europe. In Italy and Germany, a long tradition of scholarship in criminal law treats police infiltration as a problem of government law-breaking. In France, a distinguished sociological tradition views undercover tactics as a privileged terrain of turf warfare between competing government agencies. Because of their interest in the entrapment defense, American academics focus largely on the criminal responsibility of targets, not operatives. More recently, American and European scholars have shifted their interest away from the criminal law, with its emphasis on the individual criminal liability of targets and undercover operatives, toward the exploration of new means for distributing responsibility among complementary institutional actors like police, prosecutors, and judges. Undercover policing has thus increasingly become a problem of criminal procedure, in which undercover tactics have come to be framed as threats to privacy, freedom of association, trial rights, and other civil liberties. As criminal investigations become increasingly transnational, criminal procedure has provided a shared framework of criticism and a familiar repertoire of solutions, facilitating national comparisons and sometimes muting national differences in regulatory norms and approach.
Chondrosarcoma and Peroxisome Proliferator‐Activated Receptor
Authors: Nishida K. , Kunisada T. , Shen Z. N. , Kadota Y. , Hashizume K. , Ozaki T.
Published: August 2008

Induction of differentiation and apoptosis in cancer cells by ligands of PPARγ is a novel therapeutic approach to malignant tumors. Chondrosarcoma (malignant cartilage tumor) and OUMS‐27 cells (cell line established from grade III human chondrosarcoma) express PPARγ. PPARγ ligands inhibited cell proliferation in a dose‐dependent manner, and induced apoptosis of OUMS‐27. The higher‐grade chondrosarcoma expressed a higher amount of antiapoptotic Bcl‐xL in vivo. The treatment of OUMS‐27 by 15d‐PGJ2, the most potent endogenous ligand for PPARγ, downregulated expression of Bcl‐xL and induced transient upregulation of proapoptotic Bax, which could accelerate cytochrome c release from mitochondria to the cytosol, followed by induction of caspase‐dependent apoptosis. 15d‐PGJ2 induced the expression of CDK inhibitor p21 protein in human chondrosarcoma cells, which appears to be involved in the mechanism of inhibition of cell proliferation. These findings suggest that targeted therapy with PPARγ ligands could be a novel strategy against chondrosarcoma.
Feedback Remodeling of Cardiac Potassium Current Expression
Authors: Xiao Ling , Xiao Jiening , Luo Xiaobin , Lin Huixian , Wang Zhiguo , Nattel Stanley
Published: August 2008

Background—

Inhibition of individual K
+
currents causes functionally based compensatory increases in other K
+
currents that minimize changes in action potential duration, a phenomenon known as repolarization reserve. The possibility that sustained K
+
channel inhibition may induce remodeling of ion current expression has not been tested. Accordingly, we assessed the effects of sustained inhibition of one K
+
current on various other cardiac ionic currents.

Methods and Results—

Adult canine left ventricular cardiomyocytes were incubated in primary culture and paced at a physiological rate (1 Hz) for 24 hours in the presence or absence of the highly selective rapid delayed-rectifier K
+
current (I
Kr
) blocker dofetilide (5 nmol/L). Sustained dofetilide exposure led to shortened action potential duration and increased repolarization reserve (manifested as a reduced action potential duration–prolonging response to I
Kr
blockade). These repolarization changes were accompanied by increased slow delayed-rectifier (I
Ks
) density, whereas I
Kr
, transient-outward (I
to
), inward-rectifier (I
K1
), L-type Ca
2+
(I
CaL
), and late Na
+
current remained unchanged. The mRNA expression corresponding to KvLQT1 and minK (real-time polymerase chain reaction) was unchanged, but their protein expression (Western blot) was increased, suggesting posttranscriptional regulation. To analyze possible mechanisms, we quantified the muscle-specific microRNA subtypes
miR
-133a and
miR
-133b, which can posttranscriptionally regulate and repress KvLQT1 protein expression without affecting mRNA expression. The expression levels of
miR
-133a and
miR
-133b were significantly decreased in cells cultured in dofetilide compared with control, possibly accounting for KvLQT1 protein upregulation.

Conclusions—

Sustained reductions in I
Kr
may lead to compensatory upregulation of I
Ks
through posttranscriptional upregulation of underlying subunits, likely mediated (at least partly) by microRNA changes. These results suggest that feedback control of ion channel expression may influence repolarization reserve.
Interaction of Upper-Tropospheric Turbulence and Gravity Waves as Obtained from Spectral and Structure Function Analyses
Authors: Lu Chungu , Koch Steven E.
Published: August 2008

Spectral and structure function analyses of horizontal velocity fields observed in the upper troposphere and lower stratosphere during the Severe Clear Air Turbulence Collides with Air Traffic (SCATCAT) field program, conducted over the Pacific, were carried out in an effort to identify the scale interactions of turbulence and small-scale gravity waves. Because of the intermittent nature of turbulence, these analyses were conducted by clearly separating out the cases when turbulence did or did not occur in the data. In the presence of turbulence, transitional power spectra from k−2 to k−5/3 were found to be associated with gravity waves and turbulence, respectively. The second-order structure function analysis was able to translate these spectral slopes into r and r 2/3 scaling, consistent with the Monin and Yaglom conversion law, in physical space, which presented clearer pictures of scale interactions between turbulence and gravity waves. The third-order structure function analysis indicated the existence of a narrow region of inverse energy cascade from the scales of turbulence up to the gravity waves scales. This inverse energy cascade region was linked to the occurrence of Kelvin–Helmholtz instability and other wave-amplifying mechanisms, which were conjectured to lead to the breaking of small-scale gravity waves and the ensuing generation of turbulence. The multifractal analyses revealed further scale breaks between gravity waves and turbulence. The roughness and intermittent properties were also calculated for turbulence and gravity waves, respectively. Based on these properties, turbulence and gravity waves in a bifractal parameter space were mapped. In this way, their physical and statistical attributes were clearly manifested and understood.
Quasigeostrophic Turbulence with Explicit Surface Dynamics: Application to the Atmospheric Energy Spectrum
Authors: Tulloch Ross , Smith K. Shafer
Published: August 2008

The horizontal wavenumber spectra of wind and temperature near the tropopause have a steep −3 slope at synoptic scales and a shallower −5/3 slope at mesoscales, with a transition between the two regimes at a wavelength of about 450 km. Here it is demonstrated that a quasigeostrophic model driven by baroclinic instability exhibits such a transition near its upper boundary (analogous to the tropopause) when surface temperature advection at that boundary is properly resolved and forced. To accurately represent surface advection at the upper and lower boundaries, the vertical structure of the model streamfunction is decomposed into four parts, representing the interior flow with the first two neutral modes, and each surface with its Green’s function solution, resulting in a system with four prognostic equations. Mean temperature gradients are applied at each surface, and a mean potential vorticity gradient consisting both of β and vertical shear is applied in the interior. The system exhibits three fundamental types of baroclinic instability: interactions between the upper and lower surfaces (Eady type), interactions between one surface and the interior (Charney type), and interactions between the barotropic and baroclinic interior modes (Phillips type). The turbulent steady states that result from each of these instabilities are distinct, and those of the former two types yield shallow kinetic energy spectra at small scales along those boundaries where mean temperature gradients are present. When both mean interior and surface gradients are present, the surface spectrum reflects a superposition of the interior-dominated −3 slope cascade at large scales, and the surface-dominated −5/3 slope cascade at small scales. The transition wavenumber depends linearly on the ratio of the interior potential vorticity gradient to the surface temperature gradient, and scales with the inverse of the deformation scale when β = 0.
A Spectral Stochastic Kinetic Energy Backscatter Scheme and Its Impact on Flow-Dependent Predictability in the ECMWF Ensemble Prediction System
Authors: Berner J. , Shutts G. J. , Leutbecher M. , Palmer T. N.
Published: August 2008

Understanding model error in state-of-the-art numerical weather prediction models and representing its impact on flow-dependent predictability remains a complex and mostly unsolved problem. Here, a spectral stochastic kinetic energy backscatter scheme is used to simulate upscale-propagating errors caused by unresolved subgrid-scale processes. For this purpose, stochastic streamfunction perturbations are generated by autoregressive processes in spectral space and injected into regions where numerical integration schemes and parameterizations in the model lead to excessive systematic kinetic energy loss. It is demonstrated how output from coarse-grained high-resolution models can be used to inform the parameters of such a scheme. The performance of the spectral backscatter scheme is evaluated in the ensemble prediction system of the European Centre for Medium-Range Weather Forecasts. Its implementation in conjunction with reduced initial perturbations results in a better spread–error relationship, more realistic kinetic-energy spectra, a better representation of forecast-error growth, improved flow-dependent predictability, improved rainfall forecasts, and better probabilistic skill. The improvement is most pronounced in the tropics and for large-anomaly events.

It is found that whereas a simplified scheme assuming a constant dissipation rate already has some positive impact, the best results are obtained for flow-dependent formulations of the unresolved processes.
A Station-Based Southern Annular Mode Index from 1884 to 2005
Authors: Visbeck Martin
Published: August 2008

Atmospheric pressure observations from the Southern Hemisphere are used to estimate monthly and annually averaged indexes of the southern annular mode (SAM) back to 1884. This analysis groups all relevant observations in the following four regions: one for Antarctica and three in the subtropical zone. Continuous surface pressure observations are available at a number of locations in the subtropical regions since the end of the nineteenth century. However, year-round observations in the subpolar region near the Antarctic continent began only during the 1940–60 period. The shorter Antarctic records seriously compromise the length of a traditionally estimated SAM index. To improve the situation “proxy” estimates of Antarctic sea level pressure anomalies are provided based on the concept of atmospheric mass conservation poleward of 20°S. This allows deriving a longer SAM index back to 1884. Several aspects of the new record, its statistical properties, seasonal trends, and the regional pressure anomaly correlations, are presented.
The Relationship Between Reported Problems Falling Asleep and Cognition Among African American Elderly
Authors: Gamaldo Alyssa A. , Allaire Jason C. , Whitfield Keith E.
Published: August 2008

This study examined the relationship between elders' cognitive performance and self-reported trouble falling asleep. Analyses were conducted on 174 older independently living, community dwelling African Americans ( M age = 72.74; range = 65 to 90). Cognitive performance was measured using the Mini-Mental State Examination, Forward Digit Span task, Backward Digit Span task, Alpha Span task, and California Verbal Learning Test. Results suggested that individuals who reported trouble falling asleep tended to perform significantly worse than individuals who did not report trouble falling asleep on measures tapping short-term memory and working memory after controlling for age, education, gender, depression, and current health. These results demonstrate that a self-report of sleep difficulty may be a unique predictor of cognitive performance.
Racializing the Glass Escalator
Authors: Wingfield Adia Harvey
Published: August 2008

Many men who work in women's professions experience a glass escalator effect that facilitates their advancement and upward mobility within these fields. Research finds that subtle aspects of the interactions, norms, and expectations in women's professions push men upward and outward into the higher-status, higher-paying, more “masculine” positions within these fields. Although most research includes minority men, little has explicitly considered how racial dynamics color these men's encounters with the mechanisms of the glass escalator. In this article, the author examines how intersections of race and gender combine to shape experiences for minority men in the culturally feminized field of nursing and finds that the upward mobility implied by the glass escalator is not uniformly available to all men who do “women's work.” The author concludes that the glass escalator is a racialized concept and a gendered one and considers the implications of this for future studies of men in feminized occupations.
Differentiating Between Substantiated, Suspected, and Unsubstantiated Maltreatment in Canada
Authors: Trocmé Nico , Knoke Della , Fallon Barbara , MacLaurin Bruce
Published: August 2008

The decision to substantiate is a key factor in determining eligibility for services and decisions to press criminal charges or to remove a child, and it is frequently the basis for selecting samples of maltreated children or to measure recidivism or intervention effectiveness. Although there is a growing body of research on case substantiation in the United States, few studies have examined this decision in other jurisdictions. Using data from the 2003 Canadian Incidence Study of Reported Child Abuse and Neglect, this study examines the profiles of a national sample of 10,010 investigations. Multivariate analyses reveal that substantiation decisions are generally made in a fashion that is relatively consistent with the clinical characteristics of cases. Along with severity of harm, parent risk factors, and housing risk factors, police referrals are among the most important predictors of case substantiation. Cases involving multiple forms of maltreatment are also more likely to be substantiated.
Weak Ties that Bind
Authors: Shearmur Richard , Motte Benjamin
Published: August 2008

Using Montreal as a case study, the authors investigate whether overlapping labor markets explain economic links between the suburbs and the central city. Despite interconnection between labor markets, they find only weak evidence of commuting ties between particular suburbs and the city center. However, economic functions—but also some services and amenities—are distributed unevenly across the metropolitan area. The authors suggest that other connections, such as those generated by occasional consumption activities, interfirm exchanges, and other weak ties could be explored to more fully understand the economic ties between constituent parts of metropolitan areas.
A Collaborative Immersio Approach to Evaluation Capacity Building
Authors: Huffman Douglas , Thomas Kelli , Lawrenz Frances
Published: August 2008

The purpose of this article is to describe a new collaborative immersion approach for developing evaluation capacity that was used in kindergarten through Grade 12 (K-12) schools and to place this new approach on a continuum of existing capacity-building methods. The continuum extends from individualistic training-oriented methods to collaborative real-world methods of building evaluation capacity. The strengths and weaknesses of various evaluation capacity building methods are analyzed and critiqued. Included are examples of capacity building focused on technical assistance, workshops, fellowships, and collaborative immersion. The authors make the case for considering a collaborative immersion approach to evaluation capacity building.
The Complexity of Measuring the Quality of Program Implementation With Observations
Authors: Brandon Paul R. , Taum Alice K. H. , Young Donald B. , Pottenger Francis M. , Speitel Thomas W.
Published: August 2008

In the growing literature on the evaluation of program implementation, less has been said about evaluating program quality than about evaluating other aspects of program implementation. Furthermore, most articles and reports in the program-implementation evaluation literature have presented only brief descriptions of how implementation instruments have been developed. In this article, the authors describe a method for evaluating the quality of implementation of middle school inquiry-based science using data from observations scaled with paired comparison judgments. The authors show the complexities of developing and applying the method, describe how they tried it out, present the results of validity and reliability analyses, and describe the method's strengths and weaknesses.
Using System Dynamics as an Evaluation Tool
Authors: Fredericks Kimberly A. , Deegan Michael , Carman Joanne G.
Published: August 2008

Evaluators are often faced with many challenges in the design and implementation of a program's evaluation. Because programs are entangled in complex networks of structures and stakeholders, they can be challenging to understand, and they often pose issues of competing and conflicting goals. However, by using a systems mapping approach to evaluation design, evaluators can identify and diagram the relationships between different variables and learn about their potential impact and unintended consequences on a program's processes. In this article, we describe how using a systems approach and causal loop mapping approach during an evaluation of a demonstration program for people with developmental disabilities helped evaluators to better understand the program's implementation and the variation in the program's outcomes.
Don't Throw Out the Baby With the Bath Water
Authors: Kessler Stacey R. , Nixon Ashley , Nelson Carnot
Published: August 2008

The current study examines the inherent challenges of the wide-scale implementation and replication of program models. Using the Healthy Family America (HFA) program model, the study reviews the adaptation/adoption debate and highlights the ways in which program adoption and program adaptation could coexist to facilitate successful program implementations. Specifically, 103 HFA program sites were evaluated based on their adherence to HFA's flexible program model. Although the results are mixed, the study presents a new way of addressing existing program implementation and replication issues.
Teaching Program Evaluation Three Selected Pillars of Pedagogy
Authors: Oliver Diane E. , Casiraghi Ann M. , Henderson Janis L. , Brooks Augustina M. , Mulsow Miriam
Published: August 2008

Two challenges often associated with teaching program evaluation at the graduate level are the need to incorporate practical skills development and being limited to a one-semester-long course offering. The existing literature provides some information concerning a practical application component; however, there is almost no discussion of pedagogy or, more specifically, the selection of teaching strategies for a program evaluation course. This article explains and analyzes a pedagogical framework that has been used to teach program evaluation at a research university. The concepts and practices described may help those who plan to teach about program evaluation and other courses involving practical application components, particularly in an adult learner context. The article consists of four sections: (a) analysis of the pedagogical framework, (b) brief overview of the course, (c) explanation of how the pedagogy was integrated into the course, and (d) conclusions.
Put to the Test
Authors: Lay J. Celeste , Stokes-Brown Atiya Kai
Published: August 2008

Despite the importance of high-stakes tests in education policy, relatively little is known about opinion on this issue. We examine racial and socioeconomic differences in support for high-stakes testing. Given the achievement gaps between racial minorities and Whites and between the lower and higher status, it would be reasonable to expect that those whose children are most likely to do well on high-stakes tests would support the policy, whereas their counterparts would oppose them. However, these groups have different histories with and optimism about the public education system as well as different perceptions about how high-stakes tests will affect their children. We find that Latinos strongly support these measures, whereas African Americans and Whites oppose them primarily because African Americans are pessimistic about improving public schools and Whites are concerned about how resources will be redistributed. We also find that those of higher status are more likely to oppose high-stakes testing.
Institutionalizing Ethics: A Synthesis of Frameworks and the Implications for HRD
Authors: Foote Marianne F. , Ruona Wendy E.A.
Published: August 2008

Today, many human resource professionals are faced with the responsibilities of implementing ethics initiatives in the workplace. The integration of ethics is becoming an aspect of organizational life to counter unethical conduct, enhance the organization's reputation, and stimulate the attraction and retention of talent. Scholars believe ethical behavior must be institutionalized—evidenced in daily practices and rooted in organizational culture—to sustain ethics in the workplace. It is becoming increasingly clear that human resource development (HRD) professionals significantly contribute, and even more, to the process of institutionalizing ethics. This article synthesizes the literature by comparing several of the frameworks for the institutionalization of ethics that have been forwarded in research and theory during the past 15 years. Implications for HRD professionals as key contributors in the institutionalization of ethics process are discussed.
A Sociable Atmosphere
Authors: Zemke Dina Marie , Shoemaker Stowe
Published: August 2008

This exploratory study examines how introducing an ambient scent affects the interactions between people within a meeting room. The study demonstrates behavioral mapping, a procedure for testing people's responses to ambient factors. The study found that introducing an ambient scent into a meeting room significantly increased the number of social interactions between the study's participants. However, the significance of the effect of the scent was moderate. The role of scent in the hospitality industry seems promising, although the small number of observations, along with certain other factors, limits the possibility for generalizing the results of this study.
Information Technology in Hotel Management
Authors: Piccoli Gabriele
Published: August 2008

Information technology can provide hospitality firms with a sustained competitive advantage, provided the technology complements operations. Based on interdisciplinary research findings with regard to the sustainability of IT-enabled competitive advantage, this article provides a framework that can help both hospitality scholars and managers formally analyze existing and proposed IT-dependent strategic initiatives. The chief element in achieving a competitive advantage is to identify the drivers of response lag, which is the time it takes for competitors to imitate an IT initiative—if they are able to do so. The drivers can be grouped into one of the following four barriers to erosion of competitive advantage: (1) IT-resources barrier, (2) complementary-resources barrier, (3) IT-project barrier, and (4) preemption barrier.
The Compelling “Hard Case” for “Green” Hotel Development
Authors: Butler Jim
Published: August 2008

Hotel developers and managers may be wary of the current emphasis on “green” hotel development, because such trends have come and gone in the past. This time, however, consumers will almost certainly continue to demand that hotels join other commercial real estate operators in constructing and operating their buildings in accordance with standards established by the U.S. Green Building Council. The so-called LEED standards (Leadership in Energy and Environmental Design) are the basis of certification for qualifying buildings. Governments are beginning to mandate reduced energy use and emissions. Whereas building a green hotel used to cost a premium, current studies show that the cost of building to LEED standards is not greater than conventional approaches, while those buildings are healthier for occupants and less expensive to operate. Although retrofitting buildings does save energy, a better approach is to construct green hotels. Current incentives for energy-saving construction and operation may diminish, and early adopters will have the best chance at those incentives.
The Role of Technology in Restaurant Revenue Management
Authors: Kimes Sheryl E.
Published: August 2008

Technology systems can support restaurant managers' efforts to improve sales and profits through revenue management. By subdividing a meal into its component sections, a manager can determine which systems to apply at a particular stage for the purpose of providing the greatest revenue benefit for a particular restaurant. In adopting technology, managers must first conduct a financial analysis to determine whether the technology's cost will be more than offset by revenue improvements. If that financial calculation is favorable, management must then consider benefits to both employees and customers and must also take into account employees' and customers' perceptions of the technology's utility and ease of use. Without those elements in place, the technology faces dim prospects no matter what its prospective financial benefit.
Interlobular and intralobular mammary stroma: Genotype may not reflect phenotype
Authors: Fleming JM , Long EL , Ginsburg E , Gerscovich D , Meltzer PS , Vonderhaar BK
Published: August 2008

Background

The normal growth and function of mammary epithelial cells depend on interactions with the supportive stroma. Alterations in this communication can lead to the progression or expansion of malignant growth. The human mammary gland contains two distinctive types of fibroblasts within the stroma. The epithelial cells are surrounded by loosely connected intralobular fibroblasts, which are subsequently surrounded by the more compacted interlobular fibroblasts. The different proximity of these fibroblasts to the epithelial cells suggests distinctive functions for these two subtypes. In this report, we compared the gene expression profiles between the two stromal subtypes.

Methods

Fresh normal breast tissue was collected from reduction mammoplasty patients and immediately placed into embedding medium and frozen on dry ice. Tissue sections were subjected to laser capture microscopy to isolate the interlobular from the intralobular fibroblasts. RNA was prepared and subjected to microarray analysis using the Affymetrix Human Genome U133 GeneChip®. Data was analyzed using the Affy and Limma packages available from Bioconductor. Findings from the microarray analysis were validated by RT-PCR and immunohistochemistry.

Results

No statistically significant difference was detected between the gene expression profiles of the interlobular and intralobular fibroblasts by microarray analysis and RT-PCR. However, for some of the genes tested, the protein expression patterns between the two subtypes of fibroblasts were significantly different.

Conclusion

This study is the first to report the gene expression profiles of the two distinct fibroblast populations within the human mammary gland. While there was no significant difference in the gene expression profiles between the groups, there was an obvious difference in the expression pattern of several proteins tested. This report also highlights the importance of studying gene regulation at both the transcriptional and post-translational level.
Male sexual ornament size is positively associated with reproductive morphology and enhanced fertility in the stalk-eyed fly Teleopsis dalmanni
Authors: Rogers David W , Denniff Matthew , Chapman Tracey , Fowler Kevin , Pomiankowski Andrew
Published: August 2008

Background

Exaggerated male ornaments and displays often evolve in species where males only provide females with ejaculates during reproduction. Although "good genes" arguments are typically invoked to explain this phenomenon, a simpler alternative is possible if variation in male reproductive quality (e.g. sperm number, ejaculate content, mating rate) is an important determinant of female reproductive success. The "phenotype-linked fertility hypothesis" states that female preference for male ornaments or displays has been selected to ensure higher levels of fertility and has driven the evolution of exaggerated male traits. Females of the stalk-eyed fly Teleopsis dalmanni must mate frequently to maintain high levels of fertility and prefer to mate with males exhibiting large eyespan, a condition-dependent sexual ornament. If eyespan indicates male reproductive quality, females could directly increase their reproductive success by mating with males with large eyespan. Here we investigate whether male eyespan indicates accessory gland and testis length, and then ask whether mating with large eyespan males affects female fertility.

Results

Male eyespan was a better predictor of two key male reproductive traits – accessory gland and testis length – than was body size alone. This positive relationship held true over three levels of increasing environmental stress during the maturation of the adult accessory glands and testes. Furthermore, females housed with a large eyespan male exhibited higher levels of fertility than those with small eyespan males.

Conclusion

Male eyespan in stalk-eyed flies is subject to strong directional mate preference and is a reliable indicator of male reproductive quality – both because males with larger eyespan have bigger accessory glands and testes, and also as they confer higher fertility on females. Fertility enhancement may have arisen because males with larger eyespan mated more often and/or because they transferred more sperm or other substances per ejaculate. The need to ensure high levels of fertility could thus have been an important selective force in the coevolution of female preference and male eyespan in stalk-eyed flies. Our results support the phenotype-linked fertility hypothesis and suggest that it might be of general importance in explaining the evolution of exaggerated male ornaments and displays in species where males only provide females with ejaculates during reproduction.
A DNA and morphology based phylogenetic framework of the ant genus Lasius with hypotheses for the evolution of social parasitism and fungiculture
Authors: Maruyama Munetoshi , Steiner Florian M , Stauffer Christian , Akino Toshiharu , Crozier Ross H , Schlick-Steiner Birgit C
Published: August 2008

Background

Ants of the genusLasiusare ecologically important and an important system for evolutionary research. Progress in evolutionary research has been hindered by the lack of a well-founded phylogeny of the subgenera, with three previous attempts disagreeing. Here we employed two mitochondrial genes (cytochrome c oxidase subunit I, 16S ribosomal RNA), comprising 1,265 bp, together with 64 morphological characters, to recover the phylogeny ofLasiusby Bayesian and Maximum Parsimony inference after exploration of potential causes of phylogenetic distortion. We use the resulting framework to infer evolutionary pathways for social parasitism and fungiculture.

Results

We recovered two well supported major lineages. One includesAcanthomyops,Austrolasius,Chthonolasius, andLasius pallitarsis, which we confirm to represent a seventh subgenus, the other clade containsDendrolasius, andLasius sensu stricto. The subgenusCautolasius, displaying neither social parasitism nor fungiculture, probably belongs to the second clade, but its phylogenetic position is not resolved at the cutoff values of node support we apply. Possible causes for previous problems with reconstructing theLasiusphylogeny include use of other reconstruction techniques, possibly more prone to instabilities in some instances, and the inclusion of phylogenetically distorting characters.

Conclusion

By establishing an updated phylogenetic framework, our study provides the basis for a later formal taxonomic revision of subgenera and for studying the evolution of various ecologically and sociobiologically relevant traits ofLasius, although there is need for future studies to include nuclear genes and additional samples from the Nearctic. Both social parasitism and fungiculture evolved twice inLasius, once in each major lineage, which opens up new opportunities for comparative analyses. The repeated evolution of social parasitism has been established for other groups of ants, though not for temporary social parasitism as found inLasius. For fungiculture, the independent emergence twice in a monophyletic group marks a novel scenario in ants. We present alternative hypotheses for the evolution of both traits, with one of each involving loss of the trait. Though less likely for both traits than later evolution without reversal, we consider reversal as sufficiently plausible to merit independent testing.
Dynamic RNA profiling in Plasmodium falciparum synchronized blood stages exposed to lethal doses of artesunate
Authors: Natalang Onguma , Bischoff Emmanuel , Deplaine Guillaume , Proux Caroline , Dillies Marie-Agnès , Sismeiro Odile , Guigon Ghislaine , Bonnefoy Serge , Patarapotikul Jintana , Mercereau-Puijalon Odile , Coppée Jean-Yves , David Peter H
Published: August 2008

Background

Translation of the genome sequence of Plasmodium sp. into biologically relevant information relies on high through-put genomics technology which includes transcriptome analysis. However, few studies to date have used this powerful approach to explore transcriptome alterations of P. falciparum parasites exposed to antimalarial drugs.

Results

The rapid action of artesunate allowed us to study dynamic changes of the parasite transcriptome in synchronous parasite cultures exposed to the drug for 90 minutes and 3 hours. Developmentally regulated genes were filtered out, leaving 398 genes which presented altered transcript levels reflecting drug-exposure. Few genes related to metabolic pathways, most encoded chaperones, transporters, kinases, Zn-finger proteins, transcription activating proteins, proteins involved in proteasome degradation, in oxidative stress and in cell cycle regulation. A positive bias was observed for over-expressed genes presenting a subtelomeric location, allelic polymorphism and encoding proteins with potential export sequences, which often belonged to subtelomeric multi-gene families. This pointed to the mobilization of processes shaping the interface between the parasite and its environment. In parallel, pathways were engaged which could lead to parasite death, such as interference with purine/pyrimidine metabolism, the mitochondrial electron transport chain, proteasome-dependent protein degradation or the integrity of the food vacuole.

Conclusion

The high proportion of over-expressed genes encoding proteins exported from the parasite highlight the importance of extra-parasitic compartments as fields for exploration in drug research which, to date, has mostly focused on the parasite itself rather than on its intra and extra erythrocytic environment. Further work is needed to clarify which transcriptome alterations observed reflect a specific response to overcome artesunate toxicity or more general perturbations on the path to cellular death.
Functional imaging of interleukin 1 beta expression in inflammatory process using bioluminescence imaging in transgenic mice
Authors: Li Limei , Fei Zhaoliang , Ren Jianke , Sun Ruilin , Liu Zhihui , Sheng Zhejin , Wang Long , Sun Xia , Yu Jun , Wang Zhugang , Fei Jian
Published: August 2008

Background

Interleukin 1 beta (IL-1β) plays an important role in a number of chronic and acute inflammatory diseases. To understand the role of IL-1β in disease processes and develop anin vivoscreening system for anti-inflammatory drugs, a transgenic mouse line was generated which incorporated the transgene firefly luciferase gene driven by a 4.5-kb fragment of the human IL-1β gene promoter. Luciferase gene expression was monitored in live mice under anesthesia using bioluminescence imaging in a number of inflammatory disease models.

Results

In a LPS-induced sepsis model, dramatic increase in luciferase activity was observed in the mice. This transgene induction was time dependent and correlated with an increase of endogenous IL-1β mRNA and pro-IL-1β protein levels in the mice. In a zymosan-induced arthritis model and an oxazolone-induced skin hypersensitivity reaction model, luciferase expression was locally induced in the zymosan injected knee joint and in the ear with oxazolone application, respectively. Dexamethasone suppressed the expression of luciferase gene both in the acute sepsis model and in the acute arthritis model.

Conclusion

Our data suggest that the transgenic mice model could be used to study transcriptional regulation of the IL-1β gene expression in the inflammatory process and evaluation the effect of anti-inflammatory drugin vivo.