bluuebunny/crossref_metadata_2025 huggingface dataset:
Soil CO2 respiration: Comparison of chemical titration, CO2 IRGA analysis and the Solvita gel system
Authors: Haney R.L. , Brinton W.F. , Evans E.
Published: May 2008

The measurement of soil carbon dioxide respiration is a means to gauge biological soil fertility. Test methods for respiration employed in the laboratory vary somewhat, and to date the equipment and labor required have somewhat limited more widespread adoption of such methodologies. The purpose of this research is to compare the results of measured soil CO2 respiration using three methods: (1) titration method; (2) infrared gas analysis (IRGA); and (3) the Solvita gel system for soil CO2 analysis. We acquired 36 soil samples from across the USA for comparison, which ranged in pH from 4.5 to 8.5, organic C from 0.8 to 4.6% and the clay content from 6 to 62%. All three methods were highly correlated with each other after 24-h of incubation (titration and Solvita r2=0.82, respirometer and Solvita r2=0.79 and titration versus respirometer r2=0.95). The 24-h (1-day) CO2 release from all three methods was also highly correlated to both basal soil respiration (7–28 days) and cumulative 28-day CO2 respiration. An additional 24 soil samples were acquired and added to the original 36, for a total of 60 soil samples. These samples were used for calibration of the Solvita gel digital color reader results using CO2-titration results and regression analysis. Regression analysis resulted in the equation y=20.6∗(Solvita number)−16.5 with an r2 of 0.83. The data suggest that the Solvita gel system for soil CO2 analysis could be a simple and easily used method to quantify soil microbial activity. Applications may also exist for the gel system for in situ measurements in surface gas chambers. Once standardized soil sampling and laboratory analysis protocols are established, the Solvita method could be easily adapted to commercial soil testing labs as an index of soil microbial activity.
Ist die Ruheherzfrequenz ein kardiovaskulärer Risikofaktor?
Authors: Cook S. , Delacrétaz E. , Hess O.M.
Published: May 2008

Die Herzfrequenz ist als kardiovaskulärer Risikofaktor über Jahre, ja Jahrzehnte nicht beachtet worden. Neuere Untersuchungen haben jedoch gezeigt, dass sowohl bei der Normalbevölkerung, aber vor allem auch bei Patienten mit Herzkrankheiten die Herzfrequenz ein wichtiger prognostischer Faktor ist, der mit dem Auftreten eines plötzlichen Herztodes oder der Entwicklung einer Herzinsuffizienz verbunden ist. Interessanterweise ist die Herzfrequenz nicht nur ein Risikofaktor für kardiovaskuläre Mortalität, sondern auch für die Gesamtmortalität. Pathophysiologisch kommt als Ursache für die erhöhte kardiovaskuläre Mortalität die Zunahme der Ruhefrequenz, die mit einer Erhöhung des myokardialen Sauerstoffverbrauchs und einer Reduktion der Koronardurchblutung (durch Verminderung der diastolischen Füllungszeit) verbunden ist, in Frage.
Positive Beeinflussung kardiovaskulärer Risikofaktoren durch Blockade des Endocannabinoidsystems
Authors: Chatterjee T. , Chatterjee T. , Ritz A. , Ince H. , Nienaber Ch. A. , Rehders T. C.
Published: May 2008

Fettleibigkeit erhöht das Risiko für kardiovaskuläre Erkrankungen. Abdominales Fettgewebe ist ein hochaktives endokrines Organ. Die Freisetzung der Stoffe führt zu einer systemischen Entzündungsreaktion, verstärktem oxidativem Stress und Gerinnungsstörungen und somit zur Arteriosklerose. Rimonabant ist der erste Endocannabinoid Rezeptorenantagonist der zur Behandlung der Adipositas, des Diabetes mellitus Typ 2 und zur positiven Beeinflussung der kardiovaskulären Risikofaktoren entwickelt wurde. Dieser Artikel soll eine Übersicht über das Endocannabinoidsystem und Rimonabant geben.
Studying California's smog
Authors: Showstack Randy
Published: May 2008

Scientists at the Scripps Institution of Oceanography began using autonomous unmanned aerial vehicles (AUAVs) last month to assess southern California's potential for climate change and better understand the sources of air pollution. The California AUAV Air Pollution Profiling Study (CAPPS) uses the vehicles to gather meteorological data as the aircraft fly through clouds and aerosol masses in southern California skies.
In Memoriam
Authors: Anonymous
Published: May 2008

Melvin J. Hill, 88, 17 December 2007, Tectonophysics, 1956

David Jones, 76, 30 October 2007, Tectonophysics, 1980
A Brief History of the End of Time
Authors: Seitz Russell
Published: May 2008

We face the end of an era of abundance. The world is running out of geological time. A generation ago, every person on the face of the Earth had a year of time on deposit in the geological column— 4.5 billion years of deep time for 4.5 billion people.

No longer! Earth's population has been growing faster than time has been passing, and with 6.5 billion people afoot, the average person's share of the geological column has shrunk to 252 days. At this rate of population growth, the supply of unexplored strata may melt away before the glaciers disappear, threatening a mass extinction of Earth scientists. Dividing the geological column equitably among the geoscientists alive today would allow each scarcely a millennium's worth of strata as the focus of their life's work, yet most commence their careers with thesis titles that lay claim to whole periods and epochs—a million‐to‐one disparity between supply and demand.
Saiz‐Lopez Receives 2007 Holton Award
Authors: Wiscombe Warren J. , Saiz‐Lopez Alfonso
Published: May 2008

Alfonso Saiz‐Lopez received the 2007 James R. Holton Junior Scientist Award at the 2007 AGU Fall Meeting in San Francisco, Calif. The award recognizes outstanding research contributions by a junior atmospheric scientist within 3 years of his or her Ph.D.
Tsunami and Its Hazards in the Indian and Pacific Oceans
Authors: Bilek Susan L.
Published: May 2008

The 26 December 2004 earthquake and tsunami that struck offshore the Sumatra‐Andaman islands with tragic effects on inhabitants around the Indian Ocean is obviously a key event in the Earth sciences. Much like other critical topics of recent years, such as environmental issues and climate change, the earthquake and tsunami affected our science in many ways, while also connecting our science with the public policy arena.

Our previous understanding of these enormous earthquakes and their resulting tsunamis had been limited to two previous magnitude 9+ events, the Chile and Alaska earthquakes of the 1960s. At that time, digital recording of global seismic data was not standard practice, and other data sets were equally limited.
Interdecadal Variability of Rainfall on a Warming Planet
Authors: Previdi Michael , Liepert Beate G.
Published: May 2008

How much will the global water cycle accelerate with global warming? In a recent study, Wentz et al. [2007] used satellite observations to show that global mean precipitation increased by 7% per °C increase in global mean surface temperature over the period between July 1987 and August 2006. This yields an absolute precipitation increase of 13.2±4.8 millimeters per year per decade, a rate of increase that is 2–3 times greater than that simulated by general circulation models (GCMs). Century‐long integrations of GCMs also yield much smaller global precipitation increases of about 1–3% per °C of global warming [Held and Soden, 2006]. Nonetheless, Wentz et al. [2007, p. 235] argue that the recent 20‐year period may “be long enough to indicate that the observed scaling relations [e.g., between precipitation and temperature] will continue on a longer time scale,” implying significant errors in climate model predictions.
China shaken by magnitude 7.9 earthquake
Authors: Showstack Randy
Published: May 2008

A magnitude 7.9 earthquake that struck the eastern Sichuan region of China on 12 May 2008 at 0628 UTC has caused more than 22,000 fatalities as of press time, and Chinese government officials have indicated that this figure could increase to 50,000. The quake also caused severe damage including landslides and cracks to 391 mostly small dams, according to an Associated Press report that cited the Xinhua News Agency and CCTV news. China's Ministry of Water Resources has dispatched several work teams to quake‐hit localities “to prevent dams that were damaged by the earthquake from bursting and endangering the lives of residents,” the ministry stated.
Challenges to Understanding Past and Future Climate in Africa: MARUM Workshop: Response of North African Ecosystems to Abrupt Climate Change; Bremen, Germany, 14–16 November 2007
Authors: Stuut Jan‐Berend , Mulitza Stefan , Prange Matthias
Published: May 2008

The future response of African ecosystems to global change is highly uncertain. North Africa is one of the regions where many state‐of‐the‐art climate models fail to reproduce major features of the monsoonal precipitation system, and consequently, projections of future changes are not coherent among different models. A 3‐day workshop brought together 50 international experts in atmosphere physics, African paleoclimate, and archaeology. The workshop aimed to explore the role of Africa in global climate change throughout the geological past, the present, and the future. The following principal recommendations resulted from the workshop.
Fundamental Astronomy, Fifth Edition
Authors: Pintér Balázs
Published: May 2008

Writing a spectacular astronomy book is relatively easy these days. The impressive images of the latest observations of the celestial world capture the attention even of those who may not be interested in anything else in the world. In the bookstores, one can find a wide variety of beautifully illustrated books that display all of the known members of the celestial realm. The books present us with the planets and their moons, the Sun, some spectacular stars and constellations, the Milky Way, other galaxies, and the incomprehensible dimensions and depths of space. Undoubtedly, all of us—regardless of age or social or academic background—need these books, simply because we would like to know where we actually live.
Outstanding Student Paper Awards
Authors: Anonymous
Published: May 2008

The following members received Outstanding Student Paper Awards at the 2007 AGU Fall Meeting, in San Francisco, Calif.
The immunobiology of cholangiocytes
Authors: Chen Xian‐Ming , O'Hara Steven P , LaRusso Nicholas F
Published: May 2008

Cholangiocytes, the epithelial cells lining bile ducts, provide the first line of defense against lumenal microbes in the biliary system. Recent advances in biliary immunity indicate that cholangiocytes express a variety of pathogen‐recognition receptors and can activate a set of intracellular signaling cascades to initiate a profound antimicrobial defense, including release of proinflammatory cytokines and chemokines, production of antimicrobial peptides and maintenance of biliary epithelial integrity. Cholangiocytes also interact with other cell types in the liver (for example, lymphocytes and Kupffer cells) through expression and release of adhesion molecules and immune mediators. Subsequently, through an intricate feedback mechanism involving both epithelial and other liver cells, a set of intracellular signaling pathways are activated to regulate the functional state of cholangiocyte responses during microbial infection. Thus, cholangiocytes are actively involved in mucosal immunity of the biliary system and represent a fine‐tuned, integral component of liver immunity.
Strategic Systems Implementation: Diffusion through Drift
Authors: Elbanna Amany R
Published: May 2008

The adoption of Enterprise Resource Planning (ERP) systems follows various paths in organisations and achieves diverse results. The traditional models of diffusion of innovation applied in information systems are not sufficient to explain such variations in adoption. This study examines the process of drift in an ERP project to answer the questions of how and why drift tends to occur in such projects. It applies Actor Network Theory to interpret the data. This analytical lens reveals that a software implementation project's fate depends on each move it takes and each party involved in handling that move. Every handling of the project by different parties could present either a positive modality (that strengthens it and pushes it forward on its track) or a negative modality (that weakens its initial form and drags it onto a different direction). The study provides an alternative view of diffusion, and an explanation of drift in the ERP case that could be extended to other technological projects. It invites practitioners to monitor the various movements of their projects and to allow strategic drift in order to achieve a successful implementation.
An Exploration of Information Systems Adoption: Tools and Skills as Cultural Artefacts - the case of a Management Information System
Authors: Bunker Deborah , Kautz Karlheinz , Anhtuan Anhtai
Published: May 2008

This paper explains the development of a skills-focused approach that can assist organisations to better anticipate hurdles to successful information systems (IS) adoption. This approach is utilised in an interpretive field study in an Australian information technology company. From a perspective that views IS as tools, the approach is used to analyse the management control skills required to use a specific management IS. A skills match between the set of management control skills assumed by the toolmaker and the skills possessed by the tool user shows why a group of users with a high degree of match adopted the tool, while another one with a low degree of match did not do so. The study thus demonstrates that the skills-focused approach is a valid and effective way of determining the appropriateness of an IS.
Theorizing Sociospatial Relations
Authors: Jessop Bob , Brenner Neil , Jones Martin
Published: May 2008

This essay seeks to reframe recent debates on sociospatial theory through the introduction of an approach that can grasp the inherently polymorphic, multidimensional character of sociospatial relations. As previous advocates of a scalar turn, we now question the privileging, in any form, of a single dimension of sociospatial processes, scalar or otherwise. We consider several recent sophisticated ‘turns’ within critical social science; explore their methodological limitations; and highlight several important strands of sociospatial theory that seek to transcend the latter. On this basis, we argue for a more systematic recognition of polymorphy—the organization of sociospatial relations in multiple forms—within sociospatial theory. Specifically, we suggest that territories (T), places (P), scales (S), and networks (N) must be viewed as mutually constitutive and relationally intertwined dimensions of sociospatial relations. We present this proposition as an extension of recent contributions to the spatialization of the strategic-relational approach (SRA), and we explore some of its methodological implications. We conclude by briefly illustrating the applicability of the ‘TPSN framework’ to several realms of inquiry into sociospatial processes under contemporary capitalism.
Global Peddlers and Local Networks: Migrant Cosmopolitanisms
Authors: Kothari Uma
Published: May 2008

This paper is based on the experiences of street traders from South Asia and West Africa who currently live and work in Barcelona. I argue that in the ‘informal’ and marginal spaces inhabited, utilised, and created by these traders, they produce forms of nonelite cosmopolitanism through which livelihoods are sustained, social bonds are strengthened, and fluid, diasporic identities are produced. These are enabled by the development and maintenance of globalised networks and allegiances that are negotiated in highly localised ways and are often based on religion, ethnicity, and nationality. Thus, mobile and abiding cultural characteristics coexist as peddlers’ experiences of travelling and their encounters in place challenge conventional notions of cosmopolitanism and parochialism, and their apparent dualism. The paper introduces the notion of a strategic cosmopolitanism that emerges out of the need for vulnerable individuals and groups to make a living in an environment characterised by insecurity, and concludes by enquiring whether there are temporal dimensions to their cosmopolitanism.
Making Neoliberal States of Development: The Ghanaian Diaspora and the Politics of Homelands
Authors: Mohan Giles
Published: May 2008

For impoverished African states the attraction of inward flows of capital is vital and migrants are one such source of finance. Some governments actively encourage this, which brings out tensions between national affiliation and more particularistic forms of identification. This paper examines this in the context of Ghana. Between the mid-1970s and the late 1990s there was largescale out-migration from Ghana, creating what has been termed a ‘neo-diaspora’. The migrants have mainly settled in cities in Western Europe and North America where they have developed institutional networks linking them to other diasporic locations and to Ghana. These migrants have complex identities forged from multiple meetings in numerous places. Some of these are rooted in hometown, clan, and family attachments and the obligations this brings. The current government (in line with many developing countries) is making a major play to ‘harness’ the diaspora for political support and inward investment. Tensions are being played out about dual citizenship and whether the migrants’ economic commitments to Ghana are matched by rights as full citizens. The Ghana government has to tread a careful path between attracting investment and garnering the right sort of political support, since people in the diaspora often have an ambivalent relationship to domestic politics. One of the vehicles through which the Ghanaian state seeks to square this is through encouraging hometown associations in various cities in the global North to fund development at the local level through various local–local partnerships. Hence, the nation, the national good, and development are being promoted through particularistic ethnic and locality-based organisations, which brings to light multiple and overlapping political communities.
Postcolonial Bombay: Decline of a Cosmopolitanism City?
Authors: McFarlane Colin
Published: May 2008

Discussions of cosmopolitanism in Bombay often focus on the rubrics of communal tension, tolerance, and violence, and frequently report the decline of a once cosmopolitan city, especially as a result of the communal riots and bombings that occurred in the early 1990s. However, claims that the city has undergone a general social transformation since the 1990s need to be tempered by the multiple forms of cosmopolitan imaginations and practices that exist in the city. There is a wide variety of alternative cosmopolitan formations—not all of them progressive—reflected in civil society organizations and lifestyle changes for different groups, and often vividly reflected in film. This paper will chart two examples of contemporary cosmopolitanism. The first part of the paper explores the cautious optimism of film in the promise of cosmopolitan Bombay during the early years of Independence, before briefly discussing how cinema later attempted to reflect the destabilizing of the postcolonial vision of urban national development. The second part of the paper begins with discussion of the contemporary cinematic portrayal of elite-oriented global cosmopolitan modernity, and then contrasts this with a different form of global cosmopolitan modernity articulated through the work of the Slum/Shack Dwellers International network. This discussion conceives of cosmopolitanism as social, marking a counterpoint to the tendency in discourses of liberal cosmopolitanism that emphasizes the agency of the globally aware individual. Methodologically, the paper seeks to demonstrate that relating often analytically separate realms such as film and civil society can provide a wider politicocultural lens through which to examine urban change.
Chronic sodium nitrite therapy augments ischemia-induced angiogenesis and arteriogenesis
Authors: Kumar Dinesh , Branch Billy G. , Pattillo Christopher B. , Hood Jay , Thoma Stephen , Simpson Stephen , Illum Sandra , Arora Neeraj , Chidlow John H. , Langston Will , Teng Xinjun , Lefer David J. , Patel Rakesh P. , Kevil Christopher G.
Published: May 2008

Chronic tissue ischemia due to defective vascular perfusion is a hallmark feature of peripheral artery disease for which minimal therapeutic options exist. We have reported that sodium nitrite therapy exerts cytoprotective effects against acute ischemia/reperfusion injury in both heart and liver, consistent with the model of bioactive NO formation from nitrite during ischemic stress. Here, we test the hypothesis that chronic sodium nitrite therapy can selectively augment angiogenic activity and tissue perfusion in the murine hind-limb ischemia model. Various therapeutic doses (8.25–3,300 μg/kg) of sodium nitrite or PBS were administered. Sodium nitrite significantly restored ischemic hind-limb blood flow in a time-dependent manner, with low-dose sodium nitrite being most effective. Nitrite therapy significantly increased ischemic limb vascular density and stimulated endothelial cell proliferation. Remarkably, the effects of sodium nitrite therapy were evident within 3 days of the ischemic insult demonstrating the potency and efficacy of chronic sodium nitrite therapy. Sodium nitrite therapy also increased ischemic tissue nitrite and NO metabolites compared to nonischemic limbs. Use of the NO scavenger carboxy PTIO completely abolished sodium nitrite-dependent ischemic tissue blood flow and angiogenic activity consistent with nitrite reduction to NO being the proangiogenic mechanism. These data demonstrate that chronic sodium nitrite therapy is a recently discovered therapeutic treatment for peripheral artery disease and critical limb ischemia.
The evolution of imperfect floral mimicry
Authors: Vereecken Nicolas J. , Schiestl Florian P.
Published: May 2008

The theory of mimicry predicts that selection favors signal refinement in mimics to optimally match the signals released by their specific model species. We provide here chemical and behavioral evidence that a sexually deceptive orchid benefits from its mimetic imperfection to its co-occurring and specific bee model by triggering a stronger response in male bees, which react more intensively to the similar, but novel, scent stimulus provided by the orchid.
Synthesis and bioassay of improved mosquito repellents predicted from chemical structure
Authors: Katritzky Alan R. , Wang Zuoquan , Slavov Svetoslav , Tsikolia Maia , Dobchev Dimitar , Akhmedov Novruz G. , Hall C. Dennis , Bernier Ulrich R. , Clark Gary G. , Linthicum Kenneth J.
Published: May 2008

Mosquito repellency data on acylpiperidines derived from the U.S. Department of Agriculture archives were modeled by using molecular descriptors calculated by CODESSA PRO software. An artificial neural network model was developed for the correlation of these archival results and used to predict the repellent activity of novel compounds of similar structures. A series of 34 promising
N
-acylpiperidine mosquito repellent candidates (4a–4q′) were synthesized by reactions of acylbenzotriazoles 2a–2p with piperidines 3a–3f. Compounds (4a–4q′) were screened as topically applied mosquito repellents by measuring the duration of repellency after application to cloth patches worn on the arms of human volunteers. Some compounds that were evaluated repelled mosquitoes as much as three times longer than
N
,
N
-diethyl-
m
-toluamide (DEET), the most widely used repellent throughout the world. The newly measured durations of repellency were used to obtain a superior correlation equation relating mosquito repellency to molecular structure.
The evolution of courtship behaviors through the origination of a new gene in
Drosophila
Authors: Dai Hongzheng , Chen Ying , Chen Sidi , Mao Qiyan , Kennedy David , Landback Patrick , Eyre-Walker Adam , Du Wei , Long Manyuan
Published: May 2008

New genes can originate by the combination of sequences from unrelated genes or their duplicates to form a chimeric structure. These chimeric genes often evolve rapidly, suggesting that they undergo adaptive evolution and may therefore be involved in novel phenotypes. Their functions, however, are rarely known. Here, we describe the phenotypic effects of a chimeric gene,
sphinx
, that has recently evolved in
Drosophila melanogaster
. We show that a knockout of this gene leads to increased male–male courtship in
D. melanogaster
, although it leaves other aspects of mating behavior unchanged. Comparative studies of courtship behavior in other closely related
Drosophila
species suggest that this mutant phenotype of male–male courtship is the ancestral condition because these related species show much higher levels of male–male courtship than
D. melanogaster
.
D. melanogaster
therefore seems to have evolved in its courtship behaviors by the recruitment of a new chimeric gene.
Contemporary North American influenza H7 viruses possess human receptor specificity: Implications for virus transmissibility
Authors: Belser Jessica A. , Blixt Ola , Chen Li-Mei , Pappas Claudia , Maines Taronna R. , Van Hoeven Neal , Donis Ruben , Busch Julia , McBride Ryan , Paulson James C. , Katz Jacqueline M. , Tumpey Terrence M.
Published: May 2008

Avian H7 influenza viruses from both the Eurasian and North American lineage have caused outbreaks in poultry since 2002, with confirmed human infection occurring during outbreaks in The Netherlands, British Columbia, and the United Kingdom. The majority of H7 infections have resulted in self-limiting conjunctivitis, whereas probable human-to-human transmission has been rare. Here, we used glycan microarray technology to determine the receptor-binding preference of Eurasian and North American lineage H7 influenza viruses and their transmissibility in the ferret model. We found that highly pathogenic H7N7 viruses from The Netherlands in 2003 maintained the classic avian-binding preference for α2–3-linked sialic acids (SA) and are not readily transmissible in ferrets, as observed previously for highly pathogenic H5N1 viruses. However, H7N3 viruses isolated from Canada in 2004 and H7N2 viruses from the northeastern United States isolated in 2002–2003 possessed an HA with increased affinity toward α2–6-linked SA, the linkage type found prominently on human tracheal epithelial cells. We identified a low pathogenic H7N2 virus isolated from a man in New York in 2003, A/NY/107/03, which replicated efficiently in the upper respiratory tract of ferrets and was capable of transmission in this species by direct contact. These results indicate that H7 influenza viruses from the North American lineage have acquired sialic acid-binding properties that more closely resemble those of human influenza viruses and have the potential to spread to naïve animals.
Phonetic explanation without compromise
Authors: Blevins Juliette
Published: May 2008

Blust (2005, 2007a, 2007b) questions the phonetic motivation of a number of well-attested sound changes. One sound change in this class is the purported case of stressed vowel syncope in Mussau, an Oceanic language (Blust 1984, 2001, 2007a). Regular syncopes typically target unstressed vowels. By contrast, loss of stressed vowels is difficult to motivate, due to their inherent prominence. Close inspection of Mussau historical phonology suggests that, at its origins, syncope was limited to unstressed vowels, with subsequent developments obscuring its original phonetic motivation. Under the proposed analysis, the Neogrammarian insistence on phonetically motivated sound change is maintained.
Tag questions in Welsh
Authors: Rottet Kevin J. , Sprouse Rex A.
Published: May 2008

Modern Colloquial Welsh (MCW) displays a considerable variety of tag question patterns. In this paper we offer a unified account for the divergent developments in modern Welsh dialects, focusing on tags attached to “normal” or VSO clauses. We propose a scenario of how the MCW system of tags is descended from the pre-modern system by processes of reanalysis and grammaticalization. We show that South Walian dialects have elaborated a system of tag questions in which the tag reverses the polarity of the anchor to which it is attached, while North Walian dialects have followed a principle of constant polarity in which tags anticipate the polarity of the expected response.
Promoting investment by Chinese learners in classroom discourse
Authors: Trent John
Published: May 2008

Within the English language teaching profession there is now general acceptance of the advantages of integrating language and content teaching. Yet challenges continue over how such integration can be accomplished within individual classrooms. In Asian universities using English as the medium of instruction (EMI), one of the key barriers to integration is the alleged reticence of learners to participate in spoken discourse within the classroom. If the language policy aims of these institutions are to be realized, these constraints need to be acknowledged. This paper uses a multidimensional investment framework to investigate the oral participation of one group of foreign language learners within their English for academic purposes (EAP) classroom at an EMI university in Hong Kong. Drawing on data from interviews, classroom observations, audiovisual recordings of classroom interaction, and documentary analysis, this paper argues that the successful integration of language and content teaching should include an appreciation of the institutional forces that constrain and enable learners’ oral investment, how learners deploy a variety of knowledge, skills and understandings in support of this investment, and the degree of freedom learners enjoy in shaping the processes and products of their investments. The implications of this research for classroom practices are explored.
The VEGF receptor Flt-1 spatially modulates Flk-1 signaling and blood vessel branching
Authors: Kappas Nicholas C. , Zeng Gefei , Chappell John C. , Kearney Joseph B. , Hazarika Surovi , Kallianos Kimberly G. , Patterson Cam , Annex Brian H. , Bautch Victoria L.
Published: May 2008

Blood vessel formation requires the integrated regulation of endothelial cell proliferation and branching morphogenesis, but how this coordinated regulation is achieved is not well understood. Flt-1 (vascular endothelial growth factor [VEGF] receptor 1) is a high affinity VEGF-A receptor whose loss leads to vessel overgrowth and dysmorphogenesis. We examined the ability of Flt-1 isoform transgenes to rescue the vascular development of embryonic stem cell–derived flt-1−/− mutant vessels. Endothelial proliferation was equivalently rescued by both soluble (sFlt-1) and membrane-tethered (mFlt-1) isoforms, but only sFlt-1 rescued vessel branching. Flk-1 Tyr-1173 phosphorylation was increased in flt-1−/− mutant vessels and partially rescued by the Flt-1 isoform transgenes. sFlt-1–rescued vessels exhibited more heterogeneous levels of pFlk than did mFlt-1–rescued vessels, and reporter gene expression from the flt-1 locus was also heterogeneous in developing vessels. Our data support a model whereby sFlt-1 protein is more efficient than mFlt-1 at amplifying initial expression differences, and these amplified differences set up local discontinuities in VEGF-A ligand availability that are important for proper vessel branching.
Distinct versus overlapping functions of MDC1 and 53BP1 in DNA damage response and tumorigenesis
Authors: Minter-Dykhouse Katherine , Ward Irene , Huen Michael S.Y. , Chen Junjie , Lou Zhenkun
Published: May 2008

The importance of the DNA damage response (DDR) pathway in development, genomic stability, and tumor suppression is well recognized. Although 53BP1 and MDC1 have been recently identified as critical upstream mediators in the cellular response to DNA double-strand breaks, their relative hierarchy in the ataxia telangiectasia mutated (ATM) signaling cascade remains controversial. To investigate the divergent and potentially overlapping functions of MDC1 and 53BP1 in the ATM response pathway, we generated mice deficient for both genes. Unexpectedly, the loss of both MDC1 and 53BP1 neither significantly increases the severity of defects in DDR nor increases tumor incidence compared with the loss of MDC1 alone. We additionally show that MDC1 regulates 53BP1 foci formation and phosphorylation in response to DNA damage. These results suggest that MDC1 functions as an upstream regulator of 53BP1 in the DDR pathway and in tumor suppression.
Vesicles and actin are targeted to the cleavage furrow via furrow microtubules and the central spindle
Authors: Albertson Roger , Cao Jian , Hsieh Tao-shih , Sullivan William
Published: May 2008

During cytokinesis, cleavage furrow invagination requires an actomyosin-based contractile ring and addition of new membrane. Little is known about how this actin and membrane traffic to the cleavage furrow. We address this through live analysis of fluorescently tagged vesicles in postcellularized Drosophila melanogaster embryos. We find that during cytokinesis, F-actin and membrane are targeted as a unit to invaginating furrows through formation of F-actin–associated vesicles. F-actin puncta strongly colocalize with endosomal, but not Golgi-derived, vesicles. These vesicles are recruited to the cleavage furrow along the central spindle and a distinct population of microtubules (MTs) in contact with the leading furrow edge (furrow MTs). We find that Rho-specific guanine nucleotide exchange factor mutants, pebble (pbl), severely disrupt this F-actin–associated vesicle transport. These transport defects are a consequence of the pbl mutants' inability to properly form furrow MTs and the central spindle. Transport of F-actin–associated vesicles on furrow MTs and the central spindle is thus an important mechanism by which actin and membrane are delivered to the cleavage furrow.
Acetylation of mitogen-activated protein kinase phosphatase-1 inhibits Toll-like receptor signaling
Authors: Cao Wangsen , Bao Clare , Padalko Elizaveta , Lowenstein Charles J.
Published: May 2008

The mitogen-activated protein kinase (MAPK) pathway plays a critical role in Toll-like receptor (TLR) signaling. MAPK phosphatase-1 (MKP-1) inhibits the MAPK pathway and decreases TLR signaling, but the regulation of MKP-1 is not completely understood. We now show that MKP-1 is acetylated, and that acetylation regulates its ability to interact with its substrates and deactivate inflammatory signaling. We found that LPS activates acetylation of MKP-1. MKP-1 is acetylated by p300 on lysine residue K57 within its substrate-binding domain. Acetylation of MKP-1 enhances its interaction with p38, thereby increasing its phosphatase activity and interrupting MAPK signaling. Inhibition of deacetylases increases MKP-1 acetylation and blocks MAPK signaling in wild-type (WT) cells; however, deacetylase inhibitors have no effect in cells lacking MKP-1. Furthermore, histone deacetylase inhibitors reduce inflammation and mortality in WT mice treated with LPS, but fail to protect MKP-1 knockout mice. Our data suggest that acetylation of MKP-1 inhibits innate immune signaling. This pathway may be an important therapeutic target in the treatment of inflammatory diseases.
Membrane traffic and turnover in TRP-ML1–deficient cells: a revised model for mucolipidosis type IV pathogenesis
Authors: Miedel Mark T. , Rbaibi Youssef , Guerriero Christopher J. , Colletti Grace , Weixel Kelly M. , Weisz Ora A. , Kiselyov Kirill
Published: May 2008

The lysosomal storage disorder mucolipidosis type IV (MLIV) is caused by mutations in the transient receptor potential–mucolipin-1 (TRP-ML1) ion channel. The “biogenesis” model for MLIV pathogenesis suggests that TRP-ML1 modulates postendocytic delivery to lysosomes by regulating interactions between late endosomes and lysosomes. This model is based on observed lipid trafficking delays in MLIV patient fibroblasts. Because membrane traffic aberrations may be secondary to lipid buildup in chronically TRP-ML1–deficient cells, we depleted TRP-ML1 in HeLa cells using small interfering RNA and examined the effects on cell morphology and postendocytic traffic. TRP-ML1 knockdown induced gradual accumulation of membranous inclusions and, thus, represents a good model in which to examine the direct effects of acute TRP-ML1 deficiency on membrane traffic. Ratiometric imaging revealed decreased lysosomal pH in TRP-ML1–deficient cells, suggesting a disruption in lysosomal function. Nevertheless, we found no effect of TRP-ML1 knockdown on the kinetics of protein or lipid delivery to lysosomes. In contrast, by comparing degradation kinetics of low density lipoprotein constituents, we confirmed a selective defect in cholesterol but not apolipoprotein B hydrolysis in MLIV fibroblasts. We hypothesize that the effects of TRP-ML1 loss on hydrolytic activity have a cumulative effect on lysosome function, resulting in a lag between TRP-ML1 loss and full manifestation of MLIV.
Glucagon is absorbed from the rectum but does not hasten recovery from hypoglycaemia in patients with type 1 diabetes
Authors: Parker David R. , Braatvedt Geoffrey D. , Bargiota Alexandra , Newrick Paul G. , Brown Stephen , Gamble Gregory , Corrall Roger J. M.
Published: May 2008

WHAT IS ALREADY KNOWN ABOUT THIS SUBJECT

• Patients with type 1 diabetes experience recurrent hypoglycaemia and have abnormal glucose counter regulatory responses with a failure to secrete glucagon. It is unknown if rectal glucagon is absorbed and what effect this may have on counter regulation from hypoglycaemia.

WHAT THIS STUDY ADDS

• A rectal suppository of glucagon results in a rise in plasma glucagon with metabolic effects in normal subjects. Similarly rectal glucagon results in a rise in plasma glucagon in patients with type 1 diabetes, but 1 mg does not improve recovery rates from experimental hypoglycaemia when compared with placebo.

• Larger doses of glucagon per rectum may provide pharmacological circulating concentrations with resulting therapeutic benefit during recovery from hypoglycaemia and deserves further study.

AIMS

A failure to secrete glucagon during hypoglycaemia is near universal in patients with type 1 diabetes 5 years after disease onset and may contribute to delayed counter‐regulation during hypoglycaemia. Rectal glucagon delivery may assist glucose recovery following insulin‐induced hypoglycaemia in such patients and has not been previously studied.

METHODS

Six male patients (age 21–38 years) with type 1 diabetes (median duration 10 years) without microvascular complications, were studied supine after an overnight fast on two separate occasions at least 14 days apart. After omission of their usual morning insulin and 45 min rest, hypoglycaemia was induced by an intravenous insulin infusion which was terminated when capillary glucose concentration reached 2.5 mmol l−1. Subjects were randomized to insert a rectal suppository containing 100 mg indomethacin alone (placebo) or 100 mg indomethacin plus 1 mg glucagon at the hypoglycaemic reaction. Serial measurements were made for 120 min.

RESULTS

In the two groups, mean (SD) plasma glucose concentrations fell to a similar nadir of 1.8 (0.7) mmol l−1 (placebo) and 2.1 (1.2) mmol l−1 (glucagon). Peak plasma glucagon following hypoglycaemia was higher in the glucagon group; 176 (32) ng l−1vs. 99 (22) ng l−1 after placebo (P = 0.006). However, the glucose recovery rate over 120 min after hypoglycaemia did not differ significantly.

CONCLUSIONS

Our results provide evidence for the absorption of glucagon from the rectum. They also indicate that 1 mg does not constitute a useful mode of therapy to hasten recovery from hypoglycaemia in patients with type 1 diabetes.
A signal of increased risk of hypoglycaemia with angiotensin receptor blockers caused by confounding
Authors: Grégoire Fleur , Pariente Antoine , Fourrier‐Reglat Annie , Haramburu Françoise , Bégaud Bernard , Moore Nicholas
Published: May 2008

WHAT IS ALREADY KNOWN ABOUT THIS SUBJECT

• Spontaneous reporting is a valuable way to provide early detection for safety signals related to drug use.

• Due to the increasing size of pharmacovigilance databases, data‐mining and other automated methods for signal generation are more and more often used.

• Even if these methods are very useful, they do not allow, for every particular association, an automated exploration of the multiple sources of confounding.

WHAT THIS STUDY ADDS

• An association between angiotensin receptor blockers use and hypoglycaemia was found in the French pharmacovigilance database.

• This signal disappeared after stratification on antidiabetic drug use, suggesting confounding by indication.

• The association between hypoglycaemia and angiotensin receptor blocker use was actually less than expected in concomitant antidiabetic drug users.

AIMS

To study reporting of hypoglycaemia in angiotensin receptor blocker (ARB) users, and to investigate the possibility of confounding.

METHODS

The French pharmacovigilance database was examined for an association between hypoglycaemia and ARBs or other drugs using reports notified between 1996 and 2005. This association was also tested in patients taking or not taking antidiabetic agents (ADAs) using reporting odds ratios (ROR).

RESULTS

Hypoglycaemia was mentioned in 807 of the 174 595 reports entered during the study period. Overall hypoglycaemia was associated with the use of ARBs [ROR 2, 95% confidence interval (CI) 1, 3] and with the use of ADAs (ROR 32, 95% CI 27, 37). Moreover, the use of ARBs was associated with the use of ADAs (OR 7, 95% CI 6, 8). Considering separately reports with and without ADA, the association of ARB use with a higher risk of hypoglycaemia disappeared (OR 0.4, 95% CI 0.2, 0.8 and OR 2, 95% CI 1, 3, respectively).

CONCLUSION

A signal indicating an association between ARB use and hypoglycaemia was found in the French pharmacovigilance database. This signal disappeared after stratification on ADA use, thus suggesting confounding by indication. Moreover, the association between ARB use and hypoglycaemia was negative in ADA users.
The reproducibility of adenosine monophosphate bronchial challenges in mild, steroid‐naive asthmatics
Authors: Singh Dave , Fairwood Jennifer , Murdoch Robert , Weeks Amanda , Russell Paul , Roy Kay , Langley Steve , Woodcock Ashley
Published: May 2008

WHAT IS ALREADY KNOWN ABOUT THIS SUBJECT

• Repeated adenosine monophosphate (AMP) challenges are used to assess drug effects in asthma clinical trials, but may be prone to tachyphylaxis when repeated at short intervals.

• Possible tachyphylaxis at 12‐ and 24‐h intervals has not been studied.

WHAT THIS STUDY ADDS

• Clinically relevant tachyphylaxis after repeated AMP challenges does not occur when repeated at 12‐ and 24‐h intervals.

• AMP challenges at these intervals can be used to assess drug effects in clinical trials.

AIMS

Repeated adenosine monophosphate (AMP) challenges are used to assess drug efficacy in clinical trials of mild, steroid‐naive asthmatics. Refractoriness has been reported after repeated challenges over short intervals. This study evaluated possible tachyphylaxis after repeated AMP challenges at 12 and 24 h in mild, steroid‐naive asthmatics.

METHODS

This was an open, three‐way crossover study. Twenty‐six steroid‐naive asthmatic subjects were randomized to the following AMP challenge regimens separated by 7–14 days: (A) challenge at 08.00 h, repeated 24 h later; (B) challenge at 08.00 h, repeated 12 and 24 h later; (C) challenge at 20.00 h, repeated 12 h later. Comparisons within day were assessed using 90% confidence intervals (CIs). Non‐inferiority approach taken with 1 doubling concentration (DC) as a clinically relevant difference.

RESULTS

Regimen A: Significant increase in AMP reactivity at 24 h. Mean DC difference was 0.6 (90% CI 0.24, 0.96). Regimen B: No evidence of difference between AMP reactivity at 08.00 h and a repeated challenge 12 h later. Repeated challenge at 24 h caused a significant increase in provocation concentration (PC)20 compared with 12 h (mean DC difference 0.48, 90% CI 0.02, 0.95) and 0 h (mean DC difference 0.82, 90% CI 0.49, 1.14 – the upper CI exceeds the criteria of 1 DC). Challenge regimen C: No difference between challenges; mean DC difference of 0.28 (90% CI −0.2, 0.76).

CONCLUSION

The small decline in AMP reactivity during repeated challenges was not consistently observed, and was small compared with the known effects of inhaled drugs.
Diamondback moth females oviposit more on plants infested by non‐parasitised than by parasitised conspecifics
Authors: CHOH YASUYUKI , UEFUNE MASAYOSHI , TAKABAYASHI JUNJI
Published: May 2008

Abstract 1. When offered a choice, female diamondback moths (Plutella xylostella) oviposited more eggs on plants with non‐parasitised conspecific larvae than on plants with parasitised larvae.

2. The leaf area consumed by parasitised larvae was significantly lower than that by non‐parasitised larvae. However, this quantitative difference in larval damage did not explain the female’s ability to discriminate between plants with parasitised and non‐parasitised larvae, as females showed an equal oviposition preference for plants infested by higher or lower densities of non‐parasitised larvae.

3. Pupal weight and duration of the larval stage of P. xylostella were independent of whether larvae were reared on plants that were previously infested by either non‐parasitised or parasitised larvae.

4. The larval parasitoid Cotesia vestalis did not distinguish between plants infested by non‐parasitised larvae and plants infested by larvae that had already been parasitised by conspecific wasps.

5. Based on these data, it can be concluded that the moth oviposition preference for plants infested by non‐parasitised conspecifics relative to plants infested by parasitised conspecifics was not explained by plant quality or by the attractiveness of plants towards wasps. It is hypothesised that one of the reasons for this preference is avoidance of plants where a relatively high risk of parasitism is expected due to the emergence of parasitoids from the parasitised host larvae.
Rapid morphological change in stream beetle museum specimens correlates with climate change
Authors: BABIN‐FENSKE JENNIFER , ANAND MADHUR , ALARIE YVES
Published: May 2008

Abstract 1. Climate change has been occurring at unprecedented rates and its impacts on biological populations is beginning to be well documented in the literature. For many species, however, long‐term records are not available, and trends have not been documented.

2. Using museum specimens from southern USA, we show that the stream‐dwelling beetle Gyretes sinuatus has shown an 8% increase in body size and change in body shape (fineness ratio) from 1928 to 1988. Any directional morphological change observed over time could be an indicator of a microevolutionary response.

3. During these 60 years, there have also been changes in temperature, precipitation, and location of collection sites. Unlike the global trend, mean annual temperature in the region has decreased, and furthermore, total annual precipitation has increased. By investigating how these various ecological and geographical variables may affect body size and shape, we can examine which pressures may promote larger and/or thinner beetles.

4. Results indicate that mean annual temperature was the most predictive variable for the change in size and shape. We suggest there is an adaptive role for temperature on body size and shape of stream dwelling organisms.

5. We found that museum specimens can be invaluable resources of information when collection date and location information is available. We promote the use of such specimens for future studies of the morphological response to climate change.