bluuebunny/crossref_metadata_2025 huggingface dataset:
Myc stabilization in response to estrogen and phospholipase D in MCF‐7 breast cancer cells
Authors: Rodrik Vanessa , Gomes Evan , Hui Li , Rockwell Patricia , Foster David A.
Published: September 2006

Estrogen, which has been strongly implicated in breast cancer, suppresses apoptosis in estrogen receptor (ER) positive MCF‐7 breast cancer cells. Phospholipase D (PLD), which is commonly elevated in ER negative breast cancer cells, also suppresses apoptosis. Survival signals generated by both estrogen and PLD are dependent upon elevated Myc expression. We report here that estrogen‐ and PLD‐induced increases in Myc expression are due to reduced turnover of Myc protein. Estrogen and PLD suppressed phosphorylation of Myc at Thr58 – a site that targets Myc for degradation by the proteasome. The data provide a mechanism for elevated Myc expression in hormone‐dependent and hormone‐independent breast cancer.
Profiling of E‐cadherin, β‐catenin and Ca2+ in embryo–uterine interactions at implantation
Authors: Jha Rajesh Kumar , Titus Shiny , Saxena Deeksha , Kumar Pradeep G. , Laloraya Malini
Published: September 2006

Establishment of early pregnancy is promoted by a complex network of signalling molecules that mediate cell‐to‐cell and cell‐to‐extracellular matrix communications between the receptive endometrium and the invasive trophectoderm. In this study, we have attempted to evaluate the expression profiles of cadherin and catenin during embryo implantation in the mouse. Western blotting studies along with immunocytochemical analysis revealed that E‐cadherin is expressed rather ubiquitously in the uterine epithelial cells, distinct enrichment is observed on the apical membrane in the endometrium of peri‐implantation uterus specifically at the implantation sites and not at the inter‐implanation sites. β‐Catenin also is upregulated and is specifically restricted to apical membrane of epithelial cells of implantation sites. Progesterone induced expression of E‐cadherin and 17β‐estradiol regulated the expression of catenin in implantation‐delayed uteri. Interestingly, estradiol imparted negative modulation on cadherin expression when co‐administered with progesterone. On the contrary, trophoblast exhibits a striking down regulation of cadherin, catenin and Ca2+ at peri implanting stage. These observations suggest that the trophoblasts exhibited an invasive phenotype while the endometrial epithelium displayed an adhesive phenotype during the window of implantation. Thus, embryo implantation presents an instance where two interacting surfaces showed mutually complementing interaction phenotypes.
Phosphorylation‐dependent phospholipase D activity of matrix vesicles
Authors: Balcerzak Marcin , Pikula Slawomir , Buchet Rene
Published: September 2006

A progressive hydrolysis of phospholipids was observed during the mineralization process mediated by extracellular matrix vesicles. Increasing levels of different hydrolysis products revealed phospholipase A and D activities. The importance of these enzymes for the mineralization process lies in a high rate of hydrolysis of neutral phospholipids and lower rate of degradation of anionic phospholipids, which may favor mineral formation in vesicular membrane and membrane breakdown necessary for the release of mineral deposits into extracellular matrix. In this report, we focus on the phosphorylation‐dependent phospholipase D activity during mineral formation initiated by chicken embryo matrix vesicles.
Nova Scotia Politics: Clientelism and John Savage
Authors: MacLeod Jeffrey
Published: September 2006

Abstract.This paper is a test of clientelism as an explanatory framework for the challenges faced by the Nova Scotia Liberal government led by Dr. John Savage, 1993–1997. Clientelism, as an explanatory theoretical framework, is a useful tool for interpreting the political events that drove Premier Savage from office only four years after leading his party to a significant majority in the Nova Scotia legislature. The hypothesis presented is that Nova Scotia's political culture supports an environment in which clientelism flourishes. Since the clientelistic dyadic relationship and networks are deeply rooted in the cultural mores of Nova Scotia, they cannot be easily challenged and dismantled by any single political actor or government. Therefore, the Savage government's attempt to capsize this long-established cultural practice is advanced as the prime reason for its failure to endure as a viable administration.

Résumé.Cette communication est un test de clientélisme qui tente d'expliquer le cadre dans lequel s'inscrivent les défis auxquels a été confronté le gouvernement libéral de Nouvelle-Écosse mené par le DrJohn Savage de 1993 à 1997. Le clientélisme, en tant que cadre théorique explicatif, est un outil utile qui permet d'interpréter les événements politiques qui ont fait perdre son poste de Premier Ministre au DrSavage quatre ans seulement après qu'il ait mené son parti vers une majorité significative à l'assemblée législative de Nouvelle-Écosse. En fin de compte, l'hypothèse est que la culture politique de Nouvelle-Écosse favorise un environnement dans lequel le clientélisme est florissant. Du fait que la relation dyadique clientéliste et les réseaux sont profondément ancrés dans les traditions culturelles de Nouvelle-Écosse, il est peu probable qu'un acteur unique ou un simple gouvernement puisse facilement les mettre au défi et les démanteler. En conséquence, nous suggérons que la tentative du gouvernement Savage de renverser cette pratique culturelle de longue date est la raison principale pour laquelle ce gouvernement n'a pas réussi à survivre en tant qu'administration.
Racing to the Bottom? Provincial Interdependence in the Canadian
Federation
Authors: Dahlby Bev
Published: September 2006

Racing to the Bottom? Provincial Interdependence in the Canadian
Federation, Kathryn Harrison, ed., Vancouver: UBC Press, 2006, pp.
305.

There is a widely expressed concern that technological changes and
lower barriers to trade and investment have reduced governments'
ability to impose taxes on mobile inputs, such as financial capital or
venture capitalists, and this will constrain their ability to provide
basic public services and redistribute income. These forces are often
described as producing a “race to the bottom,” in which
governments compete through their tax, regulatory, and expenditure
policies to attract footloose investments.
Canada's Francophone Minority Communities: Constitutional
Renewal and the Winning of School Governance
Authors: Riddell Troy
Published: September 2006

Canada's Francophone Minority Communities: Constitutional
Renewal and the Winning of School Governance, Michael D. Behiels,
Montreal and Kingston: McGill Queen's University Press, 2004, pp.
xxx, 442.

Michael Behiels very straightforwardly sets out the purpose of his
book in the very first sentence: “This study is a descriptive
analysis of Canada's francophone minority communities' quest for
renewal and regeneration through constitutional reform and the winning of
school governance” (xxi). Behiels bases his study on archived
material from a number of francophone groups, government documents, court
decisions, interviews with five francophone activists, and a large number
of secondary sources.
A Civil Society? Collective Actors in Canadian Political Life
Authors: Phillips Susan
Published: September 2006

A Civil Society? Collective Actors in Canadian Political
Life, Miriam Smith, Peterborough: Broadview Press, 2005, pp. 224.

A curious thing about Canadian political science is that, compared to
its American or British counterparts, it offers very little analysis of
collective action outside of political parties. Even the interest groups
in Canada don't call themselves interest groups any more. So, when a
book on collective actors by a respected scholar like Miriam
Smith—who has made significant contributions to the study of
Canadian institutionalism and whose book on the lesbian and gay movement
is a gem—comes along, it is an event for the field. Because Smith
starts the book with a quote from my 1996 article with Jane Jenson on
regime shift, I was well invested from the first line and had high
expectations that Smith would not only set the macro institutional context
that she always does so well, but would provide an insightful analysis of
developments in collective action over the past decade that would build on
where Jenson and I left off.
Development Projects for a New Millennium
Authors: Culpeper Roy
Published: September 2006

Development Projects for a New Millennium, Anil Hira and
Trevor Parfitt, Westport, Conn, and London: Praeger, 2004, pp. 216.

This is a book aimed at readers who work in the “aid
business”. These include officials of bilateral and multilateral aid
agencies, and the non-government organizations and consultancies working
on contract for or independent of the official agencies. Its fundamental
premise is that aid works best if it helps its ultimate beneficiaries
realize their own goals. Much of the book provides an analysis of how the
purveyors of aid can go about achieving this objective.
Jeux d'échelle et transformation de l'État :
le gouvernement des territoires en France et au Québec.
Authors: Champagne Éric
Published: September 2006

Jeux d'échelle et transformation de l'État
: le gouvernement des territoires en France et au Québec.,
Laurence Bherer, Jean-Pierre Collin, Éric Kerrouche et Jacques
Palard (sous la direction de)., Québec : Les Presses de
l'Université Laval, Québec, 2005, 527 p.

Les réformes territoriales initiées par Louise Harel au
Québec et Jean-Pierre Chevènement en France sont au
cœur du propos de cet ouvrage. Ces transformations ont eu lieu
simultanément il y a environ cinq ans et attestent des
préoccupations de réorganisation de la gouvernance
territoriale dans ces deux États. L'ouvrage contribue à
faire progresser la réflexion sur les formes émergentes de
l'action publique territoriale en relativisant la portée de ce
mouvement par l'analyse comparative. Approximativement cinq ans
après que le Québec et la France eurent entrepris des
réformes importantes de gestion territoriale, le besoin de faire le
point et de dresser un premier bilan s'imposait. Cet ouvrage y
participe directement.
Dans l'œil du Sphinx : Claude Morin et les relations
internationales du Québec.
Authors: Michaud Nelson
Published: September 2006

Dans l'œil du Sphinx : Claude Morin et les relations
internationales du Québec., Jean Décary,
Montréal : vlb éditeur, Collection “ Études
québécoises ”, 2005. 241p.

L'année 2005 est celle des quarante ans de la fameuse
déclaration de Paul Gérin-Lajoie devant le corps consulaire
de Montréal et elle aura été marquée par un
retour à l'avant-scène des questions liées au
rôle international du Québec. Le sujet a
défrayé la manchette des chroniqueurs politiques au
momentoù Québec et Ottawa cherchaient toujours à
définir un modus operandi acceptable de part et
d'autre; un colloque d'importance a été
organisé au printemps 2005 et deux ouvrages en seront issus; enfin,
la même maison d'édition qui nous livre aujourd'hui
une analyse de la contribution de Claude Morin à
l'établissement des relations internationales du
Québec, nous avait fourni un essai sur la carrière d'un
autre acteur d'importance dans le domaine, André Patry. Le
sujet est donc d'actualité.
The Limits of Protectionism: Building Coalitions for Free
Trade
Authors: Kukucha Chris
Published: September 2006

The Limits of Protectionism: Building Coalitions for Free
Trade, Michael Lusztig, Pittsburgh: University of Pittsburgh Press,
2004, pp. xi, 272.

As the title suggests, Michael Lusztig offers a non-apologetic
endorsement of liberal trade, coalition building, and the limitations of
protectionism and rent seeking. Specifically, he argues that
“flexible” rent seekers have a better opportunity to prosper
than “inflexible” rent seekers. The goal, therefore, is for
governments to reduce rents below a specific threshold to force sectoral
interests to successfully adjust to or exit the market. Strategies include
the big bang approach, divide and conquer, iteration, and the path of
least resistance. Catalysts for change are periods of economic crisis,
international obligations, and strategic considerations in which reform is
linked to potential electoral success. Ultimately, in Lusztig's
opinion, crisis and mandated international change offer the best
opportunities for rent reduction, at least in terms of limited political
backlash.
The Science and Politics of Global Climate Change: A Guide to the
Debate
Authors: Dimitrov Radoslav S.
Published: September 2006

The Science and Politics of Global Climate Change: A Guide to the
Debate, Andrew E. Dessler and Edward A. Parson, Cambridge: Cambridge
University Press, 2006, pp. 190.

Among policy issues struggling for attention on political agendas,
climate change is particularly consequential, by virtue of its large-scale
negative consequences for all human communities and ecosystems and the
high policy costs of remedial action. The stakes are singularly high, yet
the general public is not well informed about the reality of climate
change. Even the concerned citizen seeking information gets lost between
tendentious sketches in the mass media, on the one hand, and practically
illegible specialized literature, on the other. Dessler and Parson's
work is a welcome middle ground that provides clearly comprehensible
scientifically validated information on all aspects of the issue. The book
summarizes and evaluates current information on climate change, focusing
primarily on multilateral scientific assessments conducted by the
Intergovernmental Panel on Climate Change. It offers a balanced review of
the state of knowledge, and carefully delineates the bounds of scientific
agreement and uncertainty.
A Séance with an Immortal
Authors: Sorensen Roy
Published: September 2006

To understand death, you need to compare mortality with immortality. I am here to help. In addition to my personal testimony, I present highlights from a survey of immortal species and a survey of infinitistic varieties of mortality. These field studies rebut Fredrich Nietzsche’s thesis that immortality is inevitably repetitious, Bernard Williams’ allegation that immortality is inevitably boring, and Epicurus’ thesis that death cannot be bad for you. On the positive side, the study shows that the main difference between immortality and mortality are quantitative. Attention is also given to some striking qualitative differences.
10.1017/S0031819106317029Kant and Maria von Herbert: Reticence vs. Deception
Authors: Mahon James
Published: September 2006

This article argues for a distinction between reticence and lying on the basis of what Kant says about reticence in his correspondence with Maria von Herbert and in his other ethical writings, and defends this distinction against the objections of Rae Langton (‘Duty and Desolation’, Philosophy 67, No. 262 (October 1992), 481–505). Lying is necessarily deceptive, whereas reticence is not necessarily deceptive. Allowing another person to remain ignorant of some matter is a form of reticence that is not deceptive. This form of reticence may be ethically permissible.
Did Wittgenstein Practise What He Preached?
Authors: Cook John
Published: September 2006

Wittgenstein made numerous pronouncements about philosophical method. But did he practice what he preached? Cook addresses this question by studying Wittgenstein’s treatment of the problem of other minds, tracing a line of argument that runs through his writings and lectures from the early 1930s to the 1950s. Cook finds that there is an inconsistency between Wittgenstein’s methodological advice and his actual practice. Instead of bringing words back from their metaphysical to their everyday use, he allows himself to use uncritically words whose provenance is clearly metaphysical.
International diffusion of new health technologies: A ten-country analysis of six health technologies
Authors: Packer Claire , Simpson Sue , Stevens Andrew ,   (on behalf of EuroScan: the European Information Network on New and Changing Health Technologies)
Published: September 2006

Objectives: The objective of this study was to examine and explain the differential international diffusion of six health innovations.

Methods: A retrospective diffusion study was undertaken of sildenafil, cyclooxygenase-II (COX II) inhibitors, beta interferon, verteporfin, deep brain stimulators, and drug-eluting coronary stents in ten countries—Australia, Canada, Denmark, France, The Netherlands, Norway, Spain, Sweden, Switzerland, and the United Kingdom. We plotted diffusion curves of daily defined doses per quarter, vials or implants per million population, and examined the association between diffusion and five key variables.

Results: Canada, Switzerland, and Sweden are generally high users of new technologies; Spain, Denmark, and particularly the United Kingdom are low users. Almost all countries experienced rapid adoption of sildenafil with diffusion to a similar level; there was variable adoption and diffusion of COX II inhibitors, verteporfin, and interferon beta; drug-eluting stents penetrated the market in a similar way in all but one country; and two countries had very different adoption patterns for deep brain stimulators. Above average health spending and the presence of health technology assessment (HTA) or other guidance reports are consistently associated with increased diffusion. Early warning activity and a national coverage decision being taken are more likely to be associated with a reduced diffusion.

Conclusions: The significant differences in diffusion between different countries are not consistent with a neat evidence-based world. The tools available to policy makers to control diffusion (early warning systems, HTA, and a fourth hurdle) play some part in influencing diffusion but need close scrutiny of how successfully they operate.
Cost-effectiveness of a preventive counseling and support package for postnatal depression
Authors: Petrou Stavros , Cooper Peter , Murray Lynne , Davidson Leslie L.
Published: September 2006

Objectives: This study reports the cost-effectiveness of a preventive intervention, consisting of counseling and specific support for the mother–infant relationship, targeted at women at high risk of developing postnatal depression.

Methods: A prospective economic evaluation was conducted alongside a pragmatic randomized controlled trial in which women considered at high risk of developing postnatal depression were allocated randomly to the preventive intervention (n = 74) or to routine primary care (n = 77). The primary outcome measure was the duration of postnatal depression experienced during the first 18 months postpartum. Data on health and social care use by women and their infants up to 18 months postpartum were collected, using a combination of prospective diaries and face-to-face interviews, and then were combined with unit costs (£, year 2000 prices) to obtain a net cost per mother–infant dyad. The nonparametric bootstrap method was used to present cost-effectiveness acceptability curves and net benefit statistics at alternative willingness to pay thresholds held by decision makers for preventing 1 month of postnatal depression.

Results: Women in the preventive intervention group were depressed for an average of 2.21 months (9.57 weeks) during the study period, whereas women in the routine primary care group were depressed for an average of 2.70 months (11.71 weeks). The mean health and social care costs were estimated at £2,396.9 per mother–infant dyad in the preventive intervention group and £2,277.5 per mother–infant dyad in the routine primary care group, providing a mean cost difference of £119.5 (bootstrap 95 percent confidence interval [CI], −535.4, 784.9). At a willingness to pay threshold of £1,000 per month of postnatal depression avoided, the probability that the preventive intervention is cost-effective is .71 and the mean net benefit is £383.4 (bootstrap 95 percent CI, −£863.3–£1,581.5).

Conclusions: The preventive intervention is likely to be cost-effective even at relatively low willingness to pay thresholds for preventing 1 month of postnatal depression during the first 18 months postpartum. Given the negative impact of postnatal depression on later child development, further research is required that investigates the longer-term cost-effectiveness of the preventive intervention in high risk women.
Model to assess the cost-effectiveness of new treatments for depression
Authors: Sobocki Patrik , Ekman Mattias , Ågren Hans , Jönsson Bengt , Rehnberg Clas
Published: September 2006

Objectives: The objective of this study was to develop a model to assess the cost-effectiveness of a new treatment for patients with depression.

Methods: A Markov simulation model was constructed to evaluate standard care for depression as performed in clinical practice compared with a new treatment for depression. Costs and effects were estimated for time horizons of 6 months to 5 years. A naturalistic longitudinal observational study provided data on costs, quality of life, and transition probabilities. Data on long-term consequences of depression and mortality risks were collected from the literature. Cost-effectiveness was quantified as quality-adjusted life-years (QALYs) gained from the new treatment compared with standard care, and the societal perspective was taken. Probabilistic analyses were conducted to present the uncertainty in the results, and sensitivity analyses were conducted on key parameters used in the model.

Results: Compared with standard care, the new hypothetical therapy was predicted to substantially decrease costs and was also associated with gains in QALYs. With an improved treatment effect of 50 percent on achieving full remission, the net cost savings were 20,000 Swedish kronor over a 5-year follow-up time, given equal costs of treatments. Patients gained .073 QALYs over 5 years. The results are sensitive to changes in assigned treatment effects.

Conclusions: The present study provides a new model for assessing the cost-effectiveness of treatments for depression by incorporating full remission as the treatment goal and QALYs as the primary outcome measure. Moreover, we show the usefulness of naturalistic real-life data on costs and quality of life and transition probabilities when modeling the disease over time.
Health economic evaluations: How to find them
Authors: Alton Viveka , Eckerlund Ingemar , Norlund Anders
Published: September 2006

Objectives: The aim of this study was to demonstrate the best way of identifying all relevant published health economic evaluation studies, which have increased in number rapidly in the past few decades. Nevertheless, health technology assessment projects are often faced with a scarcity of relevant studies.

Methods: Six bibliographic databases were searched using various individually adapted strategies. The particular example involves the cost-effectiveness of diagnosing gastroesophageal reflux disease. Inclusion and exclusion criteria were formulated.

Results: After irrelevant studies and duplicates had been excluded, sixty-eight abstracts were reviewed. We chose forty-one of them as relevant for full-text review, which identified fourteen papers as having met the inclusion criteria. Most of the relevant studies were identified by searching the National Health Service Economic Evaluation Database (NHS EED) and PubMed databases.

Conclusions: A search in NHS EED, by means of the Cochrane Library or the Center for Reviews and Dissimination, along with a supplementary search in PubMed, is generally an appropriate, cost-effective strategy. However, because “cost-effectiveness” is not consistently indexed with Medical Subject Heading terms in PubMed, all economic search terms need to be used to fully identify the relevant references.
Future costs of stroke in the Netherlands: The impact of stroke services
Authors: Struijs Jeroen N. , van Genugten Marianne L. L. , Evers Silvia M. A. A. , Ament André J. H. , Baan Caroline A. , van den Bos Geertrudis A. M.
Published: September 2006

Objectives: In the next decades, the number of stroke patients is expected to increase. Furthermore, organizational changes, such as stroke services, are expected to be implemented on a large scale. The purpose of this study is to estimate the future healthcare costs by taking into account the expected increase of stroke patients and a nationwide implementation of stroke services.

Methods: By means of a dynamic multistate life table, the total number of stroke patients can be projected. The model calculates the annual number of patients by age and gender. The total healthcare costs are calculated by multiplying the average healthcare costs specified by age, gender, and healthcare sector with the total number of stroke patients specified by age and gender.

Results: In the year 2000, the healthcare costs for stroke amounted to €1.62 billion. This amount is approximately 4.4 percent of the total national healthcare budget. Projections of the total costs of stroke based on current practice result in an increase of 28 percent (€2.08 billion) in the year 2020. A nationwide implementation of stroke services in 2020 would result in a substantial reduction of the costs of stroke (€1.81 billion: 13 percent cost reduction) compared with the regular care scenario.

Conclusions: A nationwide implementation of stroke services is a strong policy tool for cost containment of health care in an aging population like that in the Netherlands. Policy makers should optimize the organization of stroke care.
Effects of artificial lighting on the detection of plant stress with spectral reflectance remote sensing in bioregenerative life support systems
Authors: Schuerger Andrew C. , Richards Jeffrey T.
Published: September 2006

Plant-based life support systems that utilize bioregenerative technologies have been proposed for long-term human missions to both the Moon and Mars. Bioregenerative life support systems will utilize higher plants to regenerate oxygen, water, and edible biomass for crews, and are likely to significantly lower the ‘equivalent system mass’ of crewed vehicles. As part of an ongoing effort to begin the development of an automatic remote sensing system to monitor plant health in bioregenerative life support modules, we tested the efficacy of seven artificial illumination sources on the remote detection of plant stresses. A cohort of pepper plants (Capsicum annuum L.) were grown 42 days at 25 °C, 70% relative humidity, and 300 μmol m−2 s−1 of photosynthetically active radiation (PAR; from 400 to 700 nm). Plants were grown under nutritional stresses induced by irrigating subsets of the plants with 100, 50, 25, or 10% of a standard nutrient solution. Reflectance spectra of the healthy and stressed plants were collected under seven artificial lamps including two tungsten halogen lamps, plus high pressure sodium, metal halide, fluorescent, microwave, and red/blue light emitting diode (LED) sources. Results indicated that several common algorithms used to estimate biomass and leaf chlorophyll content were effective in predicting plant stress under all seven illumination sources. However, the two types of tungsten halogen lamps and the microwave illumination source yielded linear models with the highest residuals and thus the highest predictive capabilities of all lamps tested. The illumination sources with the least predictive capabilities were the red/blue LEDs and fluorescent lamps. Although the red/blue LEDs yielded the lowest residuals for linear models derived from the remote sensing data, the LED arrays used in these experiments were optimized for plant productivity and not the collection of remote sensing data. Thus, we propose that if adjusted to optimize the collection of remote sensing information from plants, LEDs remain the best candidates for illumination sources for monitoring plant stresses in bioregenerative life support systems.
W(h)ither the Drake equation?
Authors: Burchell Mark J.
Published: September 2006

For over 40 years the formalism known as the Drake equation has helped guide speculation about the likelihood of intelligent extraterrestrial life contacting us. Since the equation was formulated there have been significant advances in astronomy and astrophysics, sufficient to merit a review of the significance of the Drake equation. The equation itself is as a series of terms which, when combined, allow an informed discussion of the likelihood of contact with an alien intelligence. However, whilst it has a mathematical form (i.e. a series of terms multiplied together to give an overall probability) it is best understood not as an equation in the strictly mathematical sense. Some of the terms have a physically quantifiable, numerically based meaning (e.g. obtainable from astronomy) and some are more social in content in that they describe the behaviour and evolution of societies and thus are more social science in nature and not truly estimable without observation of a set of societies. Initially, almost all the terms had to be estimated based on informed guesswork or belief. However, in the intervening period since the early 1960s, many of the a priori scientific terms which were themselves initially so uncertain as to require estimation by guess work or belief are now, or will soon be, directly measurable from current or planned astronomical projects. This leaves the non-scientific terms as a distinct class of their own, still subject to analysis only by discussion. Thus observational astronomy has nearly caught up with parts of the Drake equation and will soon quantify the purely physical science parts of the equation. The social parts (concerning intelligent societies, etc.) are still a priori unknowable. In addition, the growth of the subject called astrobiology (i.e. the study of life in the Universe) has developed so fast that communicating with intelligent life is now increasingly seen as just one small part of a much larger discipline. The knowledge as to whether there is life per se (apart from on Earth) in our galactic neighbourhood may be obtainable in the near future directly from observation. Such knowledge will have a profound impact on mankind and will be obtained without the form of communication envisaged by the Drake equation.
Calibration of stable oxygen isotopes in Siderastrea radians (Cnidaria:Scleractinia): Implications for slow‐growing corals
Authors: Moses Christopher S. , Swart Peter K. , Dodge Richard E.
Published: September 2006

Geochemical proxies in the skeletons of corals used for the purpose of reconstructing environmental records have typically been obtained from relatively fast‐growing corals (usually >8 mm yr−1) and from only a few key genera (most commonly Porites and Montastraea). In many areas, however, there are no suitable fast‐growing corals available for such reconstructions. Here, we investigate the potential of Siderastrea radians, a slow‐growing Atlantic and Caribbean zooxanthellate coral, as an archive of sea surface temperature (SST) and salinity over the period from 1891 to 2002. Sampling the skeleton of three corals from the Cape Verde Islands, we were able to reproduce a clear seasonal signal, but with limited correlation to monthly SST, arising from inadequate chronologic constraint of the individual samples. The SST‐δ18O calibration slopes for different sampling scales on several cores can range from about −9°C ‰−1 to +2°C ‰−1 (compared to other published values of around −5 to −4°C ‰−1). Careful treatment produced a δ18O–SST calibration equation where SST(°C) = 12.56(±1.20) − 3.86(±0.39)*(δc–δw). The recognition of the limitations of calibration at such small growth rates due to skeletal complexity and suspicion of environmental interferences suggests the need for careful consideration in the interpretation of climate proxy results from S. radians and other slow‐growing corals.
Spectral dependency of optical backscattering by marine particles from satellite remote sensing of the global ocean
Authors: Loisel Hubert , Nicolas Jean‐Marc , Sciandra Antoine , Stramski Dariusz , Poteau Antoine
Published: September 2006

Knowledge of the relative proportion between small‐sized and larger particles in the surface ocean is essential to understand the ocean ecology and biogeochemistry, including particle dynamics and carbon cycling. We show that this information may be assessed qualitatively from satellite observations of ocean color. Such capability is based on the estimation of spectral dependence, γ, of particulate backscattering coefficient, bbp, which is sensitive to particle size distribution. Our results obtained from satellite observations of the global ocean are supported by in situ measurements, and they demonstrate a general decrease of the spectral slope γ from oligotrophic to eutrophic regimes, although significant regional differences are observed in the relationship between γ and the chlorophyll a concentration, Chl. To first approximation, such a decrease in γ is expected to be accompanied by an increased role of larger particles. This is consistent with our field data that show relatively high concentrations of submicron particles in very clear oceanic waters. Different seasonal patterns are also observed depending on the oceanic regions. The seasonal amplitude of γ is generally higher than that of Chl and bbp in equatorial and tropical regions, and it is much lower at temperate latitudes. These spatio‐temporal patterns are interpreted in terms of processes that modify the composition of particulate assemblages and physiology of phytoplankton in response to environmental forcing. The changes in γ are clearly related to variations in the mixed layer depth and photosynthetic available radiation.
Biologic cycling of silica across a grassland bioclimosequence
Authors: Blecker S. W. , McCulley R. L. , Chadwick O. A. , Kelly E. F.
Published: September 2006

The dynamics of biologic Si cycling in grassland ecosystems are largely unknown and likely to impact mineral weathering rates regionally and diatom productivity globally; key regulatory processes in the global Si cycle are closely tied to the global carbon cycle. Across a bioclimatic sequence spanning major grassland ecosystems in the Great Plains, soil biogenic silica depth distributions are similar to that of soil organic carbon; however, unlike soil organic carbon, quantities of soil biogenic silica decrease with increasing precipitation, despite an increase in annual biogenic inputs through litterfall across the same gradient. Though comprising only 1–3% of the total Si pool, faster turnover of biogenic Si and annual cycling by grasses should positively impact mineral dissolution. Our results suggest that the largest reservoir of biogenic Si in terrestrial ecosystems resides in soils, and emphasize the potential significance of grasslands in the global biogeochemical cycle of Si.
Measurements of natural uranium concentration and isotopic composition with permil‐level precision by inductively coupled plasma–quadrupole mass spectrometry
Authors: Shen Chuan‐Chou , Lin Huei‐Ting , Chu Mei‐Fei , Yu Ein‐Fen , Wang Xianfeng , Dorale Jeffrey A.
Published: September 2006

A new analytical technique using inductively coupled plasma–quadrupole mass spectrometry (ICP‐QMS) has been developed that produces permil‐level precision in the measurement of uranium concentration ([U]) and isotopic composition (δ234U) in natural materials. A 233U‐236U double spike method was used to correct for mass fractionation during analysis. To correct for ratio drifting, samples were bracketed by uranium standard measurements. A sensitivity of 6–7 × 108 cps/ppm was generated with a sample solution uptake rate of 30 μL/min. With a measurement time of 15–20 min, standards of 30‐ng uranium produced a within‐run precision better than 3‰ (±2 R.S.D.) for δ234U and better than 2‰ for [U]. Replicate measurements made on standards show that a between‐run reproducibility of 3.5‰ for δ234U and 2‰ for [U] can be achieved. ICP‐QMS data of δ234U and [U] in seawater, coral, and speleothem materials are consistent with the data measured by other ICP‐MS and TIMS techniques. Advantages of the ICP‐QMS method include low cost, easy maintenance, simple instrumental operation, and few sample preparation steps. Sample size requirements are small, such as 10–14 mg of coral material. The results demonstrate that this technique can be applied to natural samples with various matrices.
Recent cooling of the upper ocean
Authors: Lyman John M. , Willis Josh K. , Johnson Gregory C.
Published: September 2006

We observe a net loss of 3.2 (±1.1) × 1022 J of heat from the upper ocean between 2003 and 2005. Using a broad array of in situ ocean measurements, we present annual estimates of global upper‐ocean heat content anomaly from 1993 through 2005. Including the recent downturn, the average warming rate for the entire 13‐year period is 0.33 ± 0.23 W/m2 (of the Earth's total surface area). A new estimate of sampling error in the heat content record suggests that both the recent and previous global cooling events are significant and unlikely to be artifacts of inadequate ocean sampling.
Observations of the F region height redistribution in the storm‐time ionosphere over Europe and the USA using GPS imaging
Authors: Yin Ping , Mitchell Cathryn , Bust Gary
Published: September 2006

Ionospheric imaging with GPS provides a near‐global view of the three‐dimensional time‐evolving ionosphere. This is of particular interest during storms. The focus of this paper is on the height redistribution of the plasma and in particular the longitudinal and latitudinal variations in the time of plasma uplifts. Three storms, 15 July 2000, 30 October 2003 and 20 November 2003, are studied here. Dramatic elevation of the F layer by more than one hundred kilometers was seen in the images during daytime over Europe and the USA for all three storms. All three showed an east‐west time delay of around one hour in the peak‐height elevation over some 85° longitude. The 20 November 2003 storm also showed a north‐south time delay in the change in the F‐region height with the uplift seen first at high latitudes and then low latitudes. Independent evidence from other instruments and techniques are provided as supporting evidence that the peak‐height uplifts occurred. Candidate mechanisms of the peak height changes are electric fields and neutral winds and the roles of these drivers will be investigated in future modelling studies.
Kinetic signatures during a quasi‐continuous lobe reconnection event: Cluster Ion Spectrometer (CIS) observations
Authors: Bavassano Cattaneo M. B. , Marcucci M. F. , Retinò A. , Pallocchia G. , Rème H. , Dandouras I. , Kistler L. M. , Klecker B. , Carlson C. W. , Korth A. , McCarthy M. , Lundin R. , Balogh A.
Published: September 2006

On 3 December 2001 the Cluster spacecraft observed a long‐lasting lobe reconnection event in the southern high‐latitude dusk magnetopause (MP) tailward of the cusp, during a 4 hour interval of mainly northward interplanetary magnetic field (IMF) and of sub‐Alfvénic magnetosheath flow. Almost all the MP encounters have accelerated flows (for which the Walén test has been successfully verified by Retinò et al. (2005)) as well as a large number of secondary populations related to reconnection, that is, ions of magnetosheath or magnetospheric origin which cross the MP either way. The detailed analysis of the distribution functions shows that the reconnection site frequently moves relative to the spacecraft, but simultaneous measurements by two spacecraft on opposite sides of the reconnection site indicate that the spacecraft's distance from the X line is small, i.e., below 3200 km. The vicinity to the X line throughout the event is probably the reason why the distribution functions characteristics agree with theoretical expectations on both sides of the reconnection site throughout this long event. Moreover, the detailed analysis of the distribution functions shows evidence, during a few time intervals, of dual reconnection, i.e., of reconnection simultaneously going on also in the northern hemisphere.
Reactive and nonreactive scattering of N2 from Ru(0001): A six-dimensional adiabatic study
Authors: Díaz C. , Vincent J. K. , Krishnamohan G. P. , Olsen R. A. , Kroes G. J. , Honkala K. , Nørskov J. K.
Published: September 2006

We have studied the dissociative chemisorption and scattering of N2 on and from Ru(0001), using a six-dimensional quasiclassical trajectory method. The potential energy surface, which depends on all the molecular degrees of freedom, has been built applying a modified Shepard interpolation method to a data set of results from density functional theory, employing the RPBE generalized gradient approximation. The frozen surface and Born-Oppenheimer [Ann. Phys. (Leipzig) 84, 457 (1927)] approximations were used, neglecting phonons and electron-hole pair excitations. Dissociative chemisorption probabilities are found to be very small even for translational energies much higher than the minimum reaction barrier, in good agreement with experiment. A comparison to previous low dimensional calculations shows the importance of taking into account the multidimensional effects of N2 rotation and translation parallel to the surface. The new calculations strongly suggest a much smaller role of nonadiabatic effects than previously assumed on the basis of a comparison between low dimensional results and experiments [J. Chem. Phys. 115, 9028 (2001)]. Also in agreement with experiment, our theoretical results show a strong dependence of reaction on the initial vibrational state. Computed angular scattering distributions and parallel translation energy distributions are in good agreement with experiments on scattering, but the theory overestimates vibrational and rotational excitations in scattering.
Simulation study of spheroidal dust gains charging: Applicable to dust grain alignment
Authors: Zahed H. , Sobhanian S. , Mahmoodi J. , Khorram S.
Published: September 2006

The charging process of nonspherical dust grains in an unmagnetized plasma as well as in the presence of a magnetic field is studied. It is shown that unlike the spherical dust grain, due to nonhomogeneity of charge distribution on the spheroidal dust surface, the resultant electric forces on electrons and ions are different. This process produces some surface charge density gradient on the nonspherical grain surface. Effects of a magnetic field and other plasma parameters on the properties of the dust particulate are studied. It has been shown that the alignment direction could be changed or even reversed with the magnetic field and plasma parameters. Finally, the charge distribution on the spheroidal grain surface is studied for different ambient parameters including plasma temperature, neutral collision frequency, and the magnitude of the magnetic field.
Meromorphic Lax representations of (1+1)-dimensional multi-Hamiltonian dispersionless systems
Authors: Szablikowski Błażej M. , Błaszak Maciej
Published: September 2006

Rational Lax hierarchies introduced by Krichever are generalized. A systematic construction of infinite multi-Hamiltonian hierarchies and related conserved quantities is presented. The method is based on the classical R-matrix approach applied to Poisson algebras. A proof that Poisson operators constructed near different points of Laurent expansion of Lax functions are equal is given. All results are illustrated by several examples.
Infrared spectra of isotopic CO2–He complexes
Authors: McKellar A. R. W.
Published: September 2006

Infrared spectra of three isotopic forms of the weakly bound CO2–He van der Waals complex have been studied in the region of the CO2 ν3 fundamental band around 2300cm−1, using a tunable diode laser to probe a pulsed supersonic expansion. The complex is a T-shaped near-oblate asymmetric rotor, and it is found that O18 isotopic substitution is sufficient to interchange the a and b inertial axes. For the symmetric isotopes, such as the normal species and the O16C13O16 and O18C13O18 forms studied here, half of the normal rotational levels of the complex are missing due to the effects of O16 (or O18) interchange symmetry. However, for asymmetrically substituted ones, such as O16C13O18, all rotational levels are present. Moreover, for the asymmetric isotope, both a- and b-type transitions were observed, so that the spectrum was much richer. The CO2–He system is of interest both as a benchmark for intermolecular potential energy surface calculations, and because CO2 is a valuable probe molecule for helium cluster spectroscopy.
New implementation of a shear-force microscope suitable to study topographical features over wide areas
Authors: Ustione A. , Cricenti A. , Piacentini M. , Felici A. C.
Published: September 2006

A new implementation of a shear-force microscope is described that uses a shear-force detection system to perform topographical imaging of large areas (∼1×1mm2). This implementation finds very interesting application in the study of archeological or artistic samples. Three dc motors are used to move a sample during a scan, allowing the probe tip to follow the surface and to face height differences of several tens of micrometers. This large-area topographical imaging mode exploits new subroutines that were added to the existing homemade software; these subroutines were created in Microsoft VISUAL BASIC 6.0 programming language. With this new feature our shear-force microscope can be used to study topographical details over large areas of archaeological samples in a nondestructive way. We show results detecting worn reliefs over a coin.
Evolution of nanoscale morphology on fracture surface of brittle metallic glass
Authors: Wang G. , Wang Y. T. , Liu Y. H. , Pan M. X. , Zhao D. Q. , Wang W. H.
Published: September 2006

The authors report the observations of periodic morphology evolution on fracture surface of a brittle metallic glassy ribbon, suggesting a wavy local stress intensity factor along the crack propagation. The authors find that the formation of nanoscale damage cavity structure is a common characteristic morphology on the fracture surfaces. On the surface of the hackle zone, these cavities assemble and generate the nanoscale swirling periodic corrugations. The elastic waves interfering with the plastic process zone on the crack front is proposed to explain such dynamic crack instability. The authors’ observations support the notion of an impinging effect of elastic waves on propagating crack front.
Guided modes in ZnO nanorods
Authors: Hauschild Robert , Kalt Heinz
Published: September 2006

For the case of hexagonal ZnO waveguides the Helmholtz equation is solved numerically taking into account the anisotropy of both index of refraction and gain, as well as the material dispersion. The intensity distribution of all waveguide modes, their energy dependence, and the confinement as a function of the nanorod diameter are discussed. The authors apply these model calculations to determine the coupling of nanorod lasers in dense arrays and to optimize the geometry of nanorods for single mode lasing.
Quantitative measurement of tip-sample interactions in amplitude modulation atomic force microscopy
Authors: Hölscher H.
Published: September 2006

The author introduces an algorithm for the reconstruction of the tip-sample interactions in amplitude modulation atomic force microscopy (“tapping mode”). The method is based on the recording of amplitude and phase versus distance curves and allows the reconstruction of tip-sample force and energy dissipation as a function of the actual tip-sample distance. The proposed algorithm is verified by a numerical simulation and applied to a silicon sample in ambient conditions.
Fabrication of patterned single-crystal SrTiO3 thin films by ion slicing and anodic bonding
Authors: Lee Yoo Seung , Djukic Djordje , Roth Ryan M. , Laibowitz Robert , Izuhara Tomoyuki , Osgood Richard M. , Bakhru Sasha , Bakhru Hassaram , Si Weidong , Welch David
Published: September 2006

A new technique for directly fabricating patterned thin films (<1μm thick) of fully single-crystal strontium titanate uses deep H+ implantation into the oxide sample, followed by anodic bonding of the sample to a Pyrex or Pyrex-on-Si substrate. The dielectric properties and crystal structure of such thin films are characterized and are found to be essentially those of the bulk single crystal.