bluuebunny/crossref_metadata_2025 huggingface dataset:
Brief Report: A Bioassay to Identify Primary Human Prostate Cancer Repopulating Cells
Authors: Toivanen Roxanne , Berman David M. , Wang Hong , Pedersen John , Frydenberg Mark , Meeker Alan K. , Ellem Stuart J. , Risbridger Gail P. , Taylor Renea A.
Published: June 2011

Cancer cells are heterogeneous in both their phenotypes and ability to promote tumor growth and spread. Xenografting is used to identify the most highly capable cells of regenerating tumors, referred to as cancer repopulating cells. Because prostate cancers (PCa's) rarely grow as xenografts, indentifying PCa repopulating cells has not been possible. Here, we report improved methods to xenograft localized primary PCa tissues using chimeric grafts with neonatal mouse mesenchyme. Xenograft survival of tumor tissue was significantly increased by neonatal mesenchyme (six of six patients, 66% of grafts, versus four of six patients, 41% of grafts) and doubled the proliferation index of xenografted cancer cells. When applied to isolated PCa cells, neonatal mesenchyme effectively reconstituted PCa's and increased xenograft survival (four of nine patients; 32% of grafts with mesenchyme and 0% without), and supported active cancer cell proliferation. Using this assay, we showed that unfractionated α2β1integrinhi and α2β1integrinlo cells from primary localized PCa's demonstrated tumor formation at comparable rates, similar to previous reports using metastatic specimens. Thus, this new protocol efficiently established tumors and enabled proliferative expansion of both intact tumor tissue and fractionated cancer cells, providing a bioassay to identify and therapeutically target PCa repopulating cells.
Concise Review: Toward Stem Cell-Based Therapies for Retinal Neurodegenerative Diseases
Authors: Bull Natalie D. , Martin Keith R.
Published: June 2011

Loss of sight due to irreversible retinal neurodegeneration imposes a significant disease burden on both patients and society. Glaucoma and age-related macular degeneration are the commonest neurodegenerative blinding diseases in the developed world, and both are becoming increasingly prevalent as populations age. Our heavy reliance on our sense of sight means that visual loss often severely restricts day-to-day life, making it difficult to function without additional support. Visual impairment also limits employment possibilities, adding to the economic burden. Current therapies for many degenerative retinopathies are limited in their efficacy, often treating the effects of disease rather than the underlying causes. Consequently, the development of novel adjunctive neuroprotective and neuroregenerative treatments are important goals. Evidence from animal models suggests that stem cells could be useful as part of novel new treatment strategies for eye disease. The accessibility of the eye and extensive repertoire of available surgical techniques may facilitate the translation of stem cell-based therapies, for example, via transplantation, to the retina more rapidly than to other parts of the central nervous system. This concise review will examine how cell therapies are being applied experimentally for neuroregenerative and neuroprotective treatment of currently incurable degenerative retinal diseases. Furthermore, recent progress toward clinical translation of such therapies will be highlighted.
Debrided Skin as a Source of Autologous Stem Cells for Wound Repair
Authors: Natesan Shanmugasundaram , Wrice Nicole L. , Baer David G. , Christy Robert J.
Published: June 2011

Major traumatic injuries to the body, such as large surface area burns, limit the availability of autologous stem cell populations for wound repair. This report demonstrates that even after severe burn trauma to the body, resident stem cells present within the subcutaneous adipose tissue survive and are available for therapeutic uses. Debrided skin from wounded areas contains subcutaneous adipose tissue and can yield approximately 1.5 × 105 to 2.5 × 105 cells per milliliter of tissue. This observation indicates that tissue, which is normally discarded, could be a valuable source of stem cells. Initial immunohistochemistry of the debrided tissue localized platelet-derived growth factor receptor beta+ (PDGFR-β+) cells to perivascular niches of vascular beds. It was immunophenotypically confirmed that the cell isolates are stem cells and designated as debrided skin adipose-derived stem cells (dsASCs). Gene expression analysis of stem cell specific transcripts showed that the dsASCs maintained their stemness over serial passages. Furthermore, dsASCs were able to differentiate into adipogenic, osteogenic, and vascular cell lineages. Finally, an in vivo excision wound model in athymic rats demonstrated that the dsASCs are engrafted within a wound bed after 12 days. These data provide the first evidence that subcutaneous adipose tissue from discarded burned skin contains a viable population of stem cells that can be used for wound repair and skin regenerative therapies.
Endometrioid ovarian carcinoma in a woman with a history of infertility and multiple in‐vitro fertilization treatment cycles
Authors: Richards A. , Boogert T. , Livingstone M. , Dalrymple C.
Published: June 2011

Ovarian cancer is rarely diagnosed during assisted reproduction. Several case–control and cohort studies have described its incidence within the infertile population well after the assisted reproductive process. We present a case of endometrioid adenocarcinoma that developed during the ovarian stimulation process and show corresponding ultrasound images of its development. Copyright © 2012 ISUOG. Published by John Wiley & Sons, Ltd.
Distance‐preserving dimensionality reduction
Authors: Yang Li
Published: June 2011

This paper presents an overview of basic concepts and principles that deal with the problem of mapping high‐dimensional data to low‐dimensional space such that distances between all or some pairs of data points are preserved. It introduces related techniques and systematizes today's methods into linear methods, methods using iterative optimization, methods preserving exact distances, methods using geodesic distances, and methods using alignments of local models. It discusses these methods by focusing on their basic ideas, by summarizing their common features and differences, and by comparing their strengths and weaknesses. This paper assumes no familiarity with dimensionality reduction. The main text should be readable by people with little technical background. Technical information of important algorithms is briefly presented in sidebars, the reading of which assumes basics in statistics and matrix computation. © 2011 John Wiley & Sons, Inc. WIREs Data Mining Knowl Discov 2011 1 369–380 DOI: 10.1002/widm.39

This article is categorized under:

Technologies > Data Preprocessing

Technologies > Machine Learning
Non‐traditional Oils as Newer Feedstock for Rhamnolipids Production by Pseudomonas aeruginosa (ATCC 10145)
Authors: Pratap Amit , Wadekar Sushant , Kale Sandeep , Lali Arvind , Bhowmick Dipfi Narayan
Published: June 2011

Oils and fats serve as one of the most important renewable feedstocks for various chemicals such as lubricants, textiles auxiliaries, biodiesel and surfactants. The oils have also proved themselves to be better substrates than glucose for production of biosurfactants such as rhamnolipids. Cost is major hindrance in the commercialization of these biosurfactants and fresh refined oils cannot be used for rhamnolipid production. Non‐traditional oils such as jatropha oil, karanja oil and neem oil can be used as newer feedstock for the synthesis of rhamnolipids. Jatropha oil gave the highest production of rhamnolipids, 4.55 g/L in non‐traditional oils and the rhamnolipid concentration was comparable to that of most common oils, sunflower oil giving 5.08 g/L of rhamnolipids. The jatropha oil contained mainly linoleic acid that showed the highest consumption rate as compared to oleic and palmitic acid. Neem oil produced a lower concentration of rhamnolipids (2.63 g/L) than other oils. Both monorhamnolipids and dirhamnolipids were synthesized using these oils. The product obtained can find high value specialty applications such as biomedical drug delivery and cosmetics.
Changes in the German Urban System—A Financial-Sector Perspective
Authors: Klagge Britta , Peter Carsten
Published: June 2011

Urban systems analysis and especially the seminal contributions of the Globalization and World Cities Research Network (GaWC) so far mainly rely on the analysis of national and international office geographies of advanced producer services firms. This paper shows how the geography of demand-supply relationships and associated knowledge flows adds important qualitative information to the office geographies of the Globalization and World Cities Research Network. It contributes to our understanding of intercity relations and networks—and thus of urban systems more generally. We illustrate our approach by looking at private equity firms and their knowledge management strategies in Germany. Empirically, we analyze private equity firms’ business relations and networks with external partners as well as their geographical organization. While private equity firms’ geographical organization in Germany is characterized by decentralized concentration with nodes in Frankfurt and regional financial centres, there is evidence that among the latter Munich plays a special role. Only in Munich has private equity—cross-fertilized by other local financial actors—initiated a self-supporting development which strengthens Munich as a financial centre. The paper illustrates how the dynamics of private equity and its knowledge management lead to Germany’s financial system having a more tiered structure and how qualitative network analysis can help deepen our understanding of urban systems development.
Cohabitation History, Marriage, and Wealth Accumulation
Authors: Vespa Jonathan , Painter Matthew A.
Published: June 2011

This study extends research on the relationship between wealth accumulation and union experiences, such as marriage and cohabitation. Using data from the National Longitudinal Survey of Youth 1979, we explore the wealth trajectories of married individuals in light of their premarital cohabitation histories. Over time, marriage positively correlates with wealth accumulation. Most married persons with a premarital cohabitation history have wealth trajectories that are indistinguishable from those without cohabitation experience, with one exception: individuals who marry their one and only cohabiting partner experience a wealth premium that is twice as large as that for married individuals who never cohabited prior to marrying. Results remain robust over time despite cohabiters’ selection out of marriage, yet vary by race/ethnicity. We conclude that relationship history may shape long-term wealth accumulation, and contrary to existing literature, individuals who marry their only cohabiting partners experience a beneficial marital outcome. It is therefore important to understand the diversity of cohabitation experiences among the married.
Plasma Adipokine and Hormone Changes in Mountaineers on Ascent to 5300 Meters
Authors: Smith Jessica D. , Cianflone Katherine , Martin Julie , Poirier Paul , Broderick Tom L. , Noël Martin
Published: June 2011

Objective

The current study evaluated multiple metabolic and inflammatory hormone responses in recreational climbers (7 men and 3 women, age 26–49 years) over 9 days. In particular, acylation-stimulating protein (ASP), which influences fat storage in adipose tissue, has not been measured at high altitude.

Methods

Serial measurements were taken at sea level (SL), or 353 m, on day 0, 4000 m on day 3, 4750 m on day 6, and 5300 m on day 9 of the expedition.

Results

Body mass index (BMI) decreased upon ascent to 5300 m from SL (SL 23.2 ± 1.5 kg/m2; 4000 m 23.2 ± 1.4 kg/m2; 4750 m 22.9 ± 1.3 kg/m2; 5300 m 22.3 ± 1.2 kg/m2; P < .001). Similarly, plasma non-esterified fatty acids and triglycerides increased, while HDL cholesterol decreased ( P < .05 to < .001) from SL to 5300 m. Acylation-stimulating protein (SL 42.2 ± 40.2 nm; 4000 m 117.0 ± 69.6 nm; 4750 m 107.9 ± 44.5 nm; 5300 m 82.2 ± 20.2 nm; P = .019) and adiponectin (SL 10.4 ± 6.5 ng/mL, 4000 m 13.9 ± 8.5 ng/mL, 4750 m 18.3 ± 8.3 ng/mL, 5300 m 14.7 ± 8.0 ng/mL; P = .015) increased, as did insulin and Interleukin-6 (IL-6) levels (up to 71% and 168%, respectively; P < .05) with no change in leptin, complement C3 (C3), high sensitivity C-reactive protein (hsCRP) or cortisol levels throughout the mountain ascent from SL to 5300 m.

Conclusion

Acylation-stimulating protein and adiponectin are increased during a 9-day period of high altitude (SL to 5300 m) exposure despite weight loss in healthy mountaineers.
ON REGULAR MODULES
Authors: CHEN HUANYIN , NICHOLSON W. K.
Published: June 2011

Several characterizations are given of (Zelmanowitz) regular modules among the torsionless modules, the locally projective modules, the nonsingular modules, and modules where certain submodules are pure. Along the way, a version of the unimodular row lemma for torsionless modules is given, and it is shown that a regular ring is left self-injective if and only if every nonsingular left module is regular.
The ρ-variation of the heat semigroup in the Hermitian setting: behaviour inL∞
Authors: Betancor J. J. , Crescimbeni R. , Torrea J. L.
Published: June 2011

Let$\mathcal{V}_\rho(\re^{-tH})$, ρ > 2, be the ρ-variation of the heat semigroup associated to the harmonic oscillatorH= ½(−Δ + |x|2). We show that iff∈L∞(ℝ), the$\mathcal{V}_\rho(\re^{-tH})$(f)(x) < ∞, a.e.x∈ ℝ. However, we find a functionG∈L∞(ℝ), such that$\mathcal{V}_\rho(\re^{-tH})$(G)(x) ∉L∞(ℝ). We also analyse the local behaviour inL∞of the operator$\mathcal{V}_\rho(\re^{-tH})$. We find that its growth is smaller than that of a standard singular integral operator. As a by-product of our work we obtain anL∞(ℝ) functionF, such that the square function

a.e.x∈ ℝ, whereis the classical Poisson kernal in ℝ.
Metapoetic Pseudonyms in Horace, Propertius and Ovid
Authors: Heslin Peter
Published: June 2011

Two poets addressed by Propertius in his first book are in fact pseudonyms. Ponticus was formed on the model of Horace's Alpinus to designate someone who embodies the antithesis of the poet's Callimachean sensibilities. Bassus is none other than Horace himself, who was then in the course of writing iambics. In the eleventh epode, Horace responded in kind by creating the pseudonyms Pettius, Lyciscus and Inachia, all of which derive from aspects of Propertius' first book. This exchange between Horace and Propertius has echoes in their later work. We conclude by examining why Ovid seems to treat Ponticus and Bassus as real poets in theTristia.
Recurrence and ergodicity of random walks on linear groups and on homogeneous spaces
Authors: GUIVARC’H Y. , RAJA C. R. E.
Published: June 2011

We discuss recurrence and ergodicity properties of random walks and associated skew products for large classes of locally compact groups and homogeneous spaces. In particular, we show that a closed subgroup of a product of finitely many linear groups over local fields supports an adapted recurrent random walk if and only if it has at most quadratic growth. We give also a detailed analysis of ergodicity properties for special classes of random walks on homogeneous spaces and for associated homeomorphisms with infinite invariant measure. The structural properties of closed subgroups of linear groups over local fields and the properties of group actions with respect to certain Radon measures associated with random walks play an important role in the proofs.
Dangerous duties: power, paternalism and the ‘responsibility to protect’
Authors: CUNLIFFE PHILIP
Published: June 2011

This article provides a critique of Louise Arbour's article ‘The responsibility to protect as a duty of care in international law and practice’. Proceeding through criticisms of Arbour's specific propositions, the thesis is advanced that the perverse effect of the ‘duty of care’ is to undermine political accountability and by extension, political responsibility. It is argued that this is an imperfect duty that no specific agent is obliged to fulfil. This poses insuperable problems of agency that are exposed in Arbour's efforts to actualise the doctrine. As there is no mechanism for enacting the ‘duty of care’, I argue that it will be powerful states that will determine the conditions under which the ‘responsibility to protect’ is discharged. This means that the ‘duty’ will remain tied to the prerogatives of states. In order to resolve this problem of agency, it will be shown how Arbour is forced to replace the idea of law with the principle of ‘might makes right’. The ‘duty of care’ is also shown to have regressive effects on the domestic sphere: the demand that states be made accountable to the international community ends up making states responsible for their people rather than to their people.
How United Nations ideas change history
Authors: WEISS THOMAS G.
Published: June 2011

This article considers the United Nations (UN) as a creator and facilitator of innovative ideas in world politics. It thereby breathes new life into the world organisation's overlooked characteristics: the quality and diversity of its intellectual leadership, and its value-based framework for dealing with the global challenges of our times. The nature of UN ideas are examined – the good, the bad, and the ugly – while recognising that most have multiple origins and various carriers, and it continues by assessing impact. Three types of UN ideas – positive, normative, and instrumental – are discussed. Positive ideas are those resting on hard evidence, open to challenge and verifiable. Normative ideas are beliefs about what the world should look like. Instrumental (which some might label ‘causal’) ideas are often about what strategy will have what result or what tactic will achieve a desirable outcome, usually less verifiable and with a normative veneer. The article then examines nine UN ideas that changed the world, before illustrating the significance of this by examining two counterfactuals: a world without the world organisation and its ideas as well as with a more creative institution.
Smooth gait optimization of a fish robot using the genetic-hill climbing algorithm
Authors: Vo Tuong Quan , Kim Hyoung Seok , Lee Byung Ryong
Published: June 2011

This paper presents a model of a three-joint (four links) carangiform fish robot. The smooth gait or smooth motion of a fish robot is optimized by using a combination of the Genetic Algorithm (GA) and the Hill Climbing Algorithm (HCA) with respect to its dynamic system. Genetic algorithm is used to create an initial set of optimal parameters for the two input torque functions of the system. This set is then optimized by using HCA to ensure that the final set of optimal parameters is a “near” global optimization result. Finally, the simulation results are presented in order to demonstrate that the proposed method is effective.
The inflectional behavior of English-origin adjectives in French
Authors: SAUGERA VALÉRIE
Published: June 2011

When adjectives of English origin are pluralized in French, they follow one of three patterns: they receive inflection, reject inflection, or accept both forms. Curiously, these patterns of morphological variation have never been analyzed. This study identifies inflection-inhibiting constraints for a closed corpus of French dictionary-attested English adjectives and reveals that uninflected and variable adjectives do violate the standard native rule of adjective agreement, yet the constraints that block inflection areFrench-derived. A second feature of these adjectival anglicisms is that the nominal counterpart, if it exists, always receives native inflection (des jeans baggyvs.des baggys). The difference in word class, and specifically the feature of grammatical gender, may account for the contrastive behavior.
A NEW SUBSPECIES OF OMPHALODES LUCILIAE (BORAGINACEAE) FROM TURKEY
Authors: Mill R. R.
Published: June 2011

Omphalodes luciliae Boiss. subsp. pisidica R.R.Mill subsp. nov. (Boraginaceae, tribe Cynoglosseae) is described from Isparta and Antalya vilayets, Turkey. Its relations with the other subspecies of Omphalodes luciliae are discussed.
IMPORTANT PLANT AREAS IN THE ARABIAN PENINSULA: 3. ‘URUQ BANI MA‘ARID
Authors: Hall M. , Miller A. G. , Llewellyn O. A. , Al-Abbasi T. M. , Al-Harbi R. J. , Al-Shammari K. F.
Published: June 2011

‘Uruq Bani Ma‘arid in Saudi Arabia is an Important Plant Area (IPA) in the Arabian Peninsula. This paper describes the flora of ‘Uruq Bani Ma‘arid, provides an up-to-date botanical checklist of the area, and gives background information on the geology and fauna. It designates the locality as an IPA due to the highest known levels of plant species diversity in the Empty Quarter and the presence of endemic Arabian taxa. In addition to conservation assessments, this study discusses socio-economic issues, threats to biodiversity conservation on ‘Uruq Bani Ma‘arid, and the future research required to build upon these preliminary studies. A new combination is made for Fagonia schweinfurthii.
A NEW AND UNUSUAL XEROPHYTIC SPECIES OF BEGONIA (BEGONIACEAE) FROM PERU
Authors: Tebbitt M. C.
Published: June 2011

A new species of Begonia (Begoniaceae), Begonia gorgonea Tebbitt, is described from Cajamarca Province in northern Peru. This species is allied to a group of Andean species that are currently classified in Begonia sect. Knesebeckia. An identification key to this species group is provided, and the IUCN conservation category of VU D2 is proposed for the new species.
Seeds of Amazonian Plants . Fernando Cornejo & John Janovec.
Authors: Stuppy Wolfgang
Published: June 2011

..
Natural and Cultural History of the Golfo Dulce Region, Costa Rica . Anton Weissenhofer, Werner Huber, Veronika Mayer, Susanne Pamperl, Anton Weber & Gerhard Aubrecht (scientific editors).
Authors: Möller Michael
Published: June 2011

..
APPENDICULA NICOBARICA (ORCHIDACEAE – EPIDENDROIDEAE – PODOCHILEAE), A NEW SPECIES FROM GREAT NICOBAR BIOSPHERE RESERVE, INDIA
Authors: Jayanthi J. , Sumathi R. , Karthigeyan K. , Narasimhan D.
Published: June 2011

Appendicula nicobarica Jayanthi, Sumathi & Karthig. (Orchidaceae) is described and illustrated from Great Nicobar Biosphere Reserve, India.
THE THEMEDA QUADRIVALVIS TALL-GRASS SAVANNAH OF OMAN AT THE CROSSROAD BETWEEN AFRICA AND ASIA
Authors: Patzelt A.
Published: June 2011

Vegetation analysis reveals that the Themeda quadrivalvis tall-grass savannah in Oman, southern Arabia, forms a clearly defined belt with strong edaphic and geomorphological characteristics. The newly described association Desmodio gangetico-Themedetum quadrivalvis ass. nov. is interpreted as an impoverished easternmost outlier of the East African savannah.
One Step Toward God
Authors: Leftow Brian
Published: June 2011

Much of traditional natural theology offers causal explanations- e.g. for the universe's existence and ability to host our sort of life. But a less-remarked strand offers ontological explanations, claiming that theories involving God are the best answers to ontological questions. Leibniz, for instance, wrote in theMonadologythat

If there is a reality in essences or possibilities, or… eternal truths, this reality must be founded on something existent… and consequently on the existence of the necessary being in whom essence involves existence… without (God) there would be nothing real in the possibilities – not only nothing existent, but also nothing possible.
Spirituality for the Godless
Authors: McGhee Michael
Published: June 2011

‘Godless’ was never a neutral term: in 1528 William Tindale talked of ‘godlesse ypocrites and infidels’ and a ‘godless generation’ is one that has turned its back on God and the paths of righteousness. An atheist, by contrast, anewand self-conscious atheist perhaps, might now wear the term as a badge of pride, to indicate their rejection both of belief and the implication of moral turpitude. Traditionally, though, those who declared themselves ‘atheist’ had a hardly better press than the ‘godlesse’, since ‘atheism’ was and in some cases still is considered a form of intellectual and moral shallowness: thus Sir Francis Bacon offers a bluff refinement of the Psalmist's verdict on the fool who says in his heart that there is no God:

The Scripture saith,The fool hath said in his heart, there is no God; it is not said,The fool hath thought in his heart; so he rather saith it, by rote to himself, as that he would have, than that he can thoroughly believe it, or be persuaded of it.
COMPLETELY REGULAR MONOIDS WITH TWO GENERATORS
Authors: PETRICH MARIO
Published: June 2011

We classify semigroups in the title according to whether they have a finite or an infinite number ofℒ-classes or ℛ-classes. For each case, we provide a concrete construction using Rees matrix semigroups and their translational hulls. An appropriate relatively free semigroup is used to complete the classification. All this is achieved by first treating the special case in which one of the generators is idempotent. We conclude by a discussion of a possible classification of 2-generator completely regular semigroups.
An integrated mechanical and chemical method for managing prostrate cover crops on permanent beds
Authors: Hulugalle N.R. , Finlay L.A. , Weaver T.B.
Published: June 2011

Cover crops in minimum or no-tilled systems are usually killed by applying one or more herbicides, thus significantly increasing costs. Applying herbicides at lower rates with mechanical interventions that do not disturb or bury cover crop residues can, however, reduce costs. Our objective was to develop a management system with the above-mentioned features for prostrate cover crops on permanent beds in an irrigated Vertisol. The implement developed consisted of a toolbar to which were attached spring-loaded pairs of parallel coulter discs, one set of nozzles between the individual coulter discs that directed a contact herbicide to the bed surfaces to kill the cover crop and a second set of nozzles located to direct the cheaper glyphosate to the furrow to kill weeds. The management system killed a prostrate cover crop with less trafficking, reduced the use of more toxic herbicides, carbon footprint, labor and risk to operators. Maximum depth of compaction was more but average increase was less than that with the boom sprayer control.
Experimental pressure sensing and technology of piezoelectric microwave/RF MEMS filters
Authors: Massaro Alessandro , Venanzoni Giuseppe , Farina Marco , Morini Antonio , Rozzi Tullio , Cingolani Roberto , Passaseo Adriana , De Vittorio Massimo
Published: June 2011

In this work, we analyze the pressure sensing of a thin film molybdenum/aluminumnitride/molybdenum (Mo/AlN/Mo) microwave/RF MEMS filter fabricated by a simple technology. After an experimental characterization in a frequency range between 1 and 36 GHz, we focused on the piezoelectric effect due to the stress properties of the piezoelectric AlN layer by applying forces by means of weights. Variations in the bandpass region of the microwave/RF filter are observed by proving high sensitivity also for low applied weights. We check by a properly designed three-dimensional (3D) finite-element method (FEM) tool the pressure-sensing property of the proposed device. Finally, we analyze the bad gap property of a chip with central defect around 40 GHz.
Pricing for scarcity? An efficiency analysis of increasing block tariffs
Authors: Monteiro Henrique , Roseta‐Palma Catarina
Published: June 2011

Water pricing schedules often contain significant nonlinearities, such as the increasing block tariff (IBT) structure that is abundantly applied for residential users. The IBT is frequently supported as a good tool for achieving the goals of equity, water conservation, and revenue neutrality but seldom has been grounded on efficiency justifications. In particular, existing literature on water pricing establishes that although efficient schedules will depend on demand and supply characteristics, IBT cannot usually be recommended. In this paper, we consider whether the explicit inclusion of scarcity considerations can strengthen the appeal of IBT. Results show that when both demand and costs react to climate factors, increasing marginal prices may come about as a response to a combination of water scarcity and customer heterogeneity. We derive testable conditions and then illustrate their application through an estimation of Portuguese residential water demand. We show that the recommended tariff schedule hinges crucially on the choice of functional form for demand.
Analytical solutions for minimization of energy use for groundwater pumping
Authors: Ahlfeld David P. , Laverty Mikaela M.
Published: June 2011

Analytical solutions are obtained for optimization formulations that minimize energy used for groundwater pumping. The formulations choose pumping rates at groundwater wells while insuring that total pumpage meets a specified demand. Such formulations might be appropriate for an urban water supply or a large−scale agricultural irrigation system. Solutions are found by applying stationarity conditions. The solutions produce simple and physically meaningful requirements on drawdowns at each well. Under certain conditions, pumping rates are optimal when the sum of the nonpumping lift and two times the drawdown at each pumping well takes a constant value across the domain. The results are examined for steady and transient conditions. The results are based on only a few assumptions on the modeled system: the response of drawdown with head is linear, and all pumping activity occurs during the same time periods. Implications of these results for well field operation are suggested.
Studying atmospheric transport through Lagrangian models
Authors: Lin John C. , Brunner Dominik , Gerbig Christoph
Published: June 2011

Lagrangian models (LMs) track the movement of fluid parcels in their moving frame of reference. As such, scientists using LMs are forced, in a way, to imagine themselves moving with the parcel and experiencing the effects of advection, turbulence, and changes in the parcel's environment. LMs have advanced in sophistication over recent decades, allowing them to be used increasingly for both scientific and societal purposes. For example, it is common practice now for researchers around the world to apply LMs to examine a wide spectrum of geophysical phenomena. Atmospheric chemists can track intercontinental transport of pollution plumes [Stohl et al., 2002] or airborne radioactivity [Wotawa et al., 2006]. By running LMs backward in time [Flesch et al., 1995; Lin et al., 2003], instrumentalists can establish the source regions of observed atmospheric species with high computational efficiency [Ryall et al., 2001]. Therefore, LMs are being used increasingly to quantify sources and sinks of greenhouse gases by combining simulations with observations in an inverse modeling framework [Trusilova et al., 2010]. Such “top‐down” emissions estimation is receiving growing acceptance as an independent tool to test the veracity of emissions inventories and to verify adherence to treaties.
Climate change report calls for iterative risk management framework
Authors: Showstack Randy
Published: June 2011

Climate change is occurring, is very likely caused by human activities, and poses significant risks for a broad range of human and natural systems, a 12 May report by the U.S. National Research Council (NRC) reaffirms. The report includes a series of recommended steps to respond to those risks. In addition, the report urges an iterative risk management framework that can adapt to new information and changing circumstances and concerns about the risks. “Each additional ton of greenhouse gases emitted commits us to further change and greater risks. In the judgment of the [NRC] Committee on America's Climate Choices, the environmental, economic, and humanitarian risks of climate change indicate a pressing need for substantial action to limit the magnitude of climate change and to prepare to adapt to its impacts,” the report states.
George Robert Tilton (1923–2010)
Authors: Mattinson James , Hopson Clifford
Published: June 2011

George Robert Tilton, professor emeritus of geochemistry at the University of California, Santa Barbara, passed away 12 October 2010 at age 87 in Eugene, Oreg. George was among those exceptionally versatile scientists whose research and teaching effectively bridged two main disciplines: chemistry and geology. He was recognized internationally as a leader in lead isotope geochemistry and uranium‐lead (U‐Pb) geochronology, fields that he helped pioneer and revolutionize. George combined analytical chemistry and mass spectrometry to attack a wide range of geological problems, particularly those concerning the age, origin, and evolution of the Earth, Moon, and solar system.
Engaging with Congress: An unexpected encounter
Authors: Dutrow Barb
Published: June 2011

AGU sent an e‐mail to all of its U.S. members on 15 March 2011, encouraging us to meet with our members of Congress and ask them to be mindful of cuts to scientific research. I decided to take the advice that I often give to students: Never miss an opportunity. I thank AGU and the public affairs staff for encouraging us to speak with our elected officials concerning science funding but, more important, for crafting and distributing “talking points” to get us over the activation energy barrier and make conversations flow coherently.
Identifying climate change threats to the arctic archaeological record
Authors: Murray Maribeth , Jensen Anne , Friesen Max
Published: June 2011

Global Climate Change and the Polar Archaeological Record; Tromsø, Norway, 15–16 February 2011; A workshop was held at the Institute of Archaeology and Social Anthropology, University of Tromsø, in Norway, to catalyze growing concern among polar archaeologists about global climate change and attendant threats to the polar archaeological and paleoecological records. Arctic archaeological sites contain an irreplaceable record of the histories of the many societies that have lived in the region over past millennia. Associated paleoecological deposits provide powerful proxy evidence for paleoclimate and ecosystem structure and function and direct evidence of species diversity, distributions, and genetic variability. Archaeological records can span most of the Holocene (the past ∼12,000 years), depending upon location, and paleoecological records extend even further. Most are largely unstudied, and, although extremely vulnerable to destruction, they are poorly monitored and not well protected. Yet these records are key to understanding how the Arctic has functioned as a system, how humans were integrated into it, and how humans may have shaped it. Such records provide a wide range of data that are not obtainable from sources such as ice and ocean cores; these data are needed for understanding the past, assessing current and projecting future conditions, and adapting to ongoing change.
News media and new media: Strong coverage of AGU Fall Meeting
Authors: Weiss Peter
Published: June 2011

As scientists at AGU's 2010 Fall Meeting engaged one another with talks, posters, and hallway chats last December, a steady stream of reporting and commentary about all things Fall Meeting spilled out from the Moscone Center in San Francisco, Calif., to audiences throughout the world. Some 150 journalists—representing print, online, and broadcast media outlets, plus freelancers—reported from the meeting. Other reporters not present at the meeting participated in press conferences and other press events via live webcasts. Writers for nearly 2 dozen Earth and space science blogs churned out Fall Meeting‐related blog postings. Twitter users also busily commented from the meeting, generating more than 4500 tweets labeled with the meeting's #AGU10 hashtag (a Twitter identity code). The outpouring of meeting‐related news and commentary added up to more than 3000 stories, of which many reached far‐flung parts of the globe, according to an analysis made using Vocus, a media monitoring service.
Research Spotlight: Modeling saturation overshoot in porous media
Authors: Tretkoff Ernie
Published: June 2011

Infiltration of water into soils or porous rocks often follows unpredictable, preferential flow paths, also known as fingers. These fingers are caused by a condition called saturation overshoot, where the water content in the finger tip is greater than the water content in the finger tail. Why this happens has puzzled researchers,as overshoot cannot occur in traditional models. DiCarlo et al. used modeling and experiments to bridge the pore‐level and continuum‐scale physics behind saturation overshoot. Their model predicts the types of soils and initial conditions that are susceptible to overshoot and preferential flow. (Water Resources Research, doi:10.1029/ 2010WR009879, 2011)
Research Spotlight: Determining the underlying pattern of Arctic snowfall
Authors: Schultz Colin
Published: June 2011

Across the Arctic terrain, more than a hundred bright orange markers dot the landscape, sticking up from the fallen snow. The fiberglass poles, standing 1.5 meters high and spaced 100 meters apart, allow Sturm and Wagner to track snow depth over their 1‐square‐kilometer research area in Alaska. These depth measurements may be simple, but trying to turn them into a prediction of future snowfall distribution is far more difficult. A rough estimate of the amount of snow expected in an area can be estimated from weather models, but the smaller‐scale distribution of snow across the landscape is often dictated by interactions among wind, topography, and vegetation, factors that models have difficulty simulating. (Water Resources Research, doi:10.1029/ 2010WR009434, 2010)
Triagency collaboration for the advancement of climate change education
Authors: Wilson Carolyn E. , Chambers Lin H. , Schoedinger Sarah
Published: June 2011

Second Annual NASA, NOAA, and NSF Climate Change Education Principal Investigators Meeting; Fairfax, Virginia, 28 February to 2 March 2011; In 2009 the Obama administration identified climate change research and education as a presidential priority. Embracing the spirit of the America COMPETES Act, which encourages coordination of federal science, technology, engineering, and mathematics (STEM) education activities and programs, NASA, the National Oceanic and Atmospheric Administration (NOAA), and the National Science Foundation (NSF) have been working together to increase funding opportunities for projects focused on global climate literacy and education in formal and informal learning environments and have fostered collaborations among awardees that create a strong national network for effectively presenting climate science to diverse audiences.
Jerolmack receives 2010 Luna B. Leopold Young Scientist Award: Response
Authors: Jerolmack Douglas J.
Published: June 2011

Douglas J. Jerolmack received the 2010 Luna B. Leopold Young Scientist Award at the 2010 AGU Fall Meeting, held 13“17 December in San Francisco, Calif. The award recognizes “a young scientist for making a significant and outstanding contribution that advances the field of Earth and planetary surface processes.”
Sea surface height and steric height increases in the Southern Hemisphere
Authors: Tretkoff Ernie
Published: June 2011

Sea surface height has increased by 3 millimeters per year, globally averaged, since 1993. Some fraction of sea surface height change is due to added water from melting glaciers, for instance, and some is due to increasing heat and salinity changes (steric effects). Focusing on the Southern Hemisphere, Sutton and Roemmich analyzed temperature and salinity data from the Argo float array in relation to earlier data from the World Ocean Circulation Experiment (WOCE) to estimate the steric changes. These were compared with the total sea surface height changes over the same period seen in satellite altimetric data. They found that on decadal time scales, about half of the rise in sea surface height in the Southern Ocean is due to steric effects, with the proportion increasing southward. The accompanying increase in ocean heat content south of 30°S can account for most of the global heat content change during this period. (Geophysical Research Letters, doi:10.1029/2011GL046802, 2011)
Ash from huge Australian bushfires in 2009 circled the globe
Authors: Kumar Mohi
Published: June 2011

On 7 February 2009, record high temperatures, low rainfall and humidity, and fast blowing winds caused sparks in the bush near the Australian city of Melbourne to ignite much of the southeastern region of the state of Victoria. In just a few days, more than 4500 square kilometers had burned and 173 people had died in what has been called the worst natural disaster in Australian history. The fires released so much smoke that daytime on 7 February was plunged into darkness in Melbourne. Indeed, soot particles and other aerosols are known to scatter and absorb solar radiation. However, airborne particles released by fires are typically thought to remain in the atmosphere close to their sources. In fact, climate models pay little attention to the scattering and absorbing effects of fire‐borne aerosols because they are not believed to reach altitudes above 10 kilometers, in the stratosphere, where circulation patterns would distribute a plume of pollution around the globe, possibly leading to global cooling effects. Ash from volcanic plumes has long been considered the sole method by which aerosols and gases could be injected into the stratosphere from the Earth's surface. However, Australia's bushfires of 2009 showed otherwise. (Journal of Geophysical Research‐Atmospheres, doi:10.1029/2010JD015162, 2011)
RNA Quadruplexes
Authors: Halder Kangkan , Hartig Jörg S.
Published: June 2011

Opposed to DNA quadruplex sequences, RNA quadruplexes are still less well characterized. On the other hand, RNA quadruplexes are found to be at least as stable as their DNA counterparts. They show the same dependence on metal ions but seem to be much more restricted with respect to the adopted conformations. Other than DNA, which is mostly found to be double-stranded inside cells, RNAs are produced during transcription without its complementary sequence. The absence of a second strand that is able to hybridize and form a duplex makes the folding of RNA quadruplexes a likely event of intramolecular structure formation. Consequently, the formation of RNA quadruplexes in cellular RNAs has recently been suggested and the study of their influence and potential roles in cellular processes has just started. Here we give an overview of the RNA quadruplex field, summarizing issues such as structures, stabilities, and anticipated roles of these interesting four-stranded, guanosine-rich sequences.
The Roles of Metal Ions in Regulation by Riboswitches
Authors: Ferré-D'Amaré Adrian R. , Winkler Wade C.
Published: June 2011

Metal ions are required by all organisms in order to execute an array of essential molecular functions. They play a critical role in many catalytic mechanisms and structural properties. Proper homeostasis of ions is critical; levels that are aberrantly low or high are deleterious to cellular physiology. To maintain stable intracellular pools, metal ion-sensing regulatory (metalloregulatory) proteins couple metal ion concentration fluctuations with expression of genes encoding for cation transport or sequestration. However, these transcriptional-based regulatory strategies are not the only mechanisms by which organisms coordinate metal ions with gene expression. Intriguingly, a few classes of signal-responsive RNA elements have also been discovered to function as metalloregulatory agents. This suggests that RNA-based regulatory strategies can be precisely tuned to intracellular metal ion pools, functionally akin to metalloregulatory proteins. In addition to these metal-sensing regulatory RNAs, there is a yet broader role for metal ions in directly assisting the structural integrity of other signal-responsive regulatory RNA elements. In this chapter, we discuss how the intimate physicochemical relationship between metal ions and nucleic acids is important for the structure and function of metal ion- and metabolite-sensing regulatory RNAs.
Multiple Roles of Metal Ions in Large Ribozymes
Authors: Donghi Daniela , Schnabl Joachim
Published: June 2011

Since the discovery of catalytic RNA molecules (ribozymes), intense research has been devoted to understand their structure and activity. Among RNA molecules, the large ribozymes, namely group I and group II introns and RNase P, are of special importance. The first two ribozymes are known for their ability to perform self-splicing while RNase P is responsible for the 5′-end maturation of tRNA in bacteria, archea, and eukaryotes. All three groups of ribozymes show a significant requirement for metal ions in order to establish the active tertiary structure that enables catalysis. The primary role of both monovalent and divalent metal ions is to screen the negative charge associated with the phosphate sugar backbone, but the metal ions also play an active role in catalysis. Biochemical and biophysical investigations, supported by recent findings from X-ray crystal structures, allow clarifying and rationalizing both the structural and catalytic roles of metal ions in large ribozymes. In particular, the “two-metal-ion mechanism”, describing how metal ions in the active center take part in catalysis, has been largely corroborated.
The Ribosome: A Molecular Machine Powered by RNA
Authors: Trappl Krista , Polacek Norbert
Published: June 2011

Metal ions are the salt in the soup of essentially every biological system. Also in the ribosome, the largest natural ribozyme that produces all proteins in every living cell, metal ions have been found contributing significantly to the highly dynamic and accurate process of translation. The ribosome is considered a molecular fossil of the ‘RNA world’ and it could be shown that the evolutionarily oldest parts of the particle, which build the catalytic center and surrounding domains, are densely packed with divalent metal ions. Nevertheless, metal ions do not seem to directly participate in ribosomal catalysis, their important roles in the ribosome, however, cannot be denied. It is probable that mono- and divalent metal ions primarily promote the functionally competent architecture of the ribosomal RNAs, but more direct roles in mRNA decoding and reading frame maintenance are likely. Decades of biochemical studies and the recent high resolution crystallographic structures of the ribosome strongly indicate that metal ions are involved in essentially every phase of the ribosomal elongation cycle, thus contributing significantly to the precise translation of the genetic code.
Metal Ion Requirements in Artificial Ribozymes that Catalyze Aminoacylation and Redox Reactions
Authors: Suga Hiroaki , Futai Kazuki , Jin Koichiro
Published: June 2011

The means of in vitro selection has yielded a number of artificial ribozymes with functions that have not been discovered as yet in modern biological systems. Like naturally occurring ribozymes, most artificial ribozymes also use metal ions for the support of catalysis. Here we choose two such ribozymes, flexizyme and ribox, that exhibit specific activities of tRNA aminoacylation and redox chemistry, respectively, and comprehensively summarize the roles of metal ions in conjunction with their structure and function.