bluuebunny/crossref_metadata_2025 huggingface dataset:
A Unique Interplay Between Rap1 and E-Cadherin in the Endocytic Pathway Regulates Self-Renewal of Human Embryonic Stem Cells
Authors: Li Li , Wang Shuai , Jezierski Anna , Moalim-Nour Lilian , Mohib Kanishka , Parks Robin J. , Francesco Retta Saverio , Wang Lisheng
Published: December 2009

Regulatory mechanisms pertaining to the self-renewal of stem cells remain incompletely understood. Here, we show that functional interactions between small GTPase Rap1 and the adhesion molecule E-cadherin uniquely regulate the self-renewal of human embryonic stem cells (hESCs). Inhibition of Rap1 suppresses colony formation and self-renewal of hESCs, whereas overexpression of Rap1 augments hESC clonogenicity. Rap1 does not directly influence the expression of the pluripotency genes Oct4 and Nanog. Instead, it affects the endocytic recycling pathway involved in the formation and maintenance of E-cadherin-mediated cell–cell cohesion, which is essential for the colony formation and self-renewal of hESCs. Conversely, distinct from epithelial cells, disruption of E-cadherin mediated cell–cell adhesions induces lysosome delivery and degradation of Rap1. This in turn leads to a further downregulation of E-cadherin function and a subsequent reduction in hESC clonogenic capacity. These findings provide the first demonstration that the interplay between Rap1 and E-cadherin along the endocytic recycling pathway serves as a timely and efficient mechanism to regulate hESC self-renewal. Given the availability of specific activators for Rap1, this work provides a new perspective to enable better maintenance of human pluripotent stem cells.
Boundary Cap Cells are Highly Competitive for CNS Remyelination: Fast Migration and Efficient Differentiation in PNS and CNS Myelin-Forming Cells
Authors: Zujovic V. , Thibaud J. , Bachelin C. , Vidal M. , Coulpier F. , Charnay P. , Topilko P. , Evercooren A. Baron-Van
Published: December 2009

During development, boundary cap cells (BC) and neural crest cell (NCC) derivatives generate Schwann cells (SC) of the spinal roots and a subpopulation of neurons and satellite cells in the dorsal root ganglia. Despite their stem-like properties, their therapeutic potential in the diseased central nervous system (CNS) was never explored. The aim of this work was to explore BC therapeutic potential for CNS remyelination. We derived BC from Krox20Cre × R26RYfp embryos at E12.5, when Krox20 is exclusively expressed by BC. Combining microdissection and cell fate mapping, we show that acutely isolated BC are a unique population closely related but distinct from NCC and SC precursors. Moreover, when grafted in the demyelinated spinal cord, BC progeny expands in the lesion through a combination of time-regulated processes including proliferation and differentiation. Furthermore, when grafted away from the lesion, BC progeny, in contrast to committed SC, show a high migratory potential mediated through enhanced interactions with astrocytes and white matter, and possibly with polysialylated neural cell adhesion molecule expression. In response to demyelinated axons of the CNS, BC progeny generates essentially myelin-forming SC. However, in contact with axons and astrocytes, some of them generate also myelin-forming oligodendrocytes. There are two primary outcomes of this study. First, the high motility of BC and their progeny, in addition to their capacity to remyelinate CNS axons, supports the view that BC are a reservoir of interest to promote CNS remyelination. Second, from a developmental point of view, BC behavior in the demyelinated CNS raises the question of the boundary between central and peripheral myelinating cells.
High-Throughput Flow Cytometry Purification of Transduced Progenitors Expressing Defined Levels of Vascular Endothelial Growth Factor Induces Controlled Angiogenesis In Vivo
Authors: Misteli Heidi , Wolff Thomas , Füglistaler Philipp , Gianni-Barrera Roberto , Gürke Lorenz , Heberer Michael , Banfi Andrea
Published: December 2009

Delivery of therapeutic genes by genetically modified progenitors is a powerful tool for regenerative medicine. However, many proteins remain localized within or around the expressing cell, and heterogeneous expression levels can lead to reduced efficacy or increased toxicity. For example, the matrix-binding vascular endothelial growth factor (VEGF) can induce normal, stable, and functional angiogenesis or aberrant angioma growth depending on its level of expression in the microenvironment around each producing cell, and not on its total dose. To overcome this limitation, we developed a flow cytometry–based method to rapidly purify transduced cells expressing desired levels of a therapeutic transgene. Primary mouse myoblasts were transduced with a bicistronic retrovirus expressing VEGF linked to a nonfunctional, truncated form of the syngenic molecule CD8a. By using a clonal population uniformly expressing a known VEGF level as a reference, cells producing similar VEGF amounts were rapidly sorted from the primary population on the basis of their CD8a fluorescence intensity. A single round of sorting with a suitably designed gate yielded a purified population that induced robust, normal, and stable angiogenesis, and completely avoided angioma growth, which was instead always caused by the heterogeneous parent population. This clinically applicable high-throughput technique allowed the delivery of highly controlled VEGF levels in vivo, leading to significantly improved safety without compromising efficacy. Furthermore, when applied to other suitable progenitor populations, this technique could help overcome a significant obstacle in the development of safe and efficacious vascularization strategies in the fields of regenerative medicine and tissue engineering.
Water‐forming NADH oxidase protects Torulopsis glabrata against hyperosmotic stress
Authors: Xu Sha , Zhou Jingwen , Qin Yi , Liu Liming , Chen Jian
Published: December 2009

A heterologous water‐forming NADH oxidase was introduced into Torulopsis glabrata and the effect on cell growth under hyperosmotic conditions was investigated. Expression of the noxE gene from Lactococcus lactis NZ9000 in T. glabrata resulted in a marked decrease in the NADH : NAD+ ratio and higher activities of key enzymes in water‐regenerating pathways, leading to an increase in intracellular water content. NaCl‐induced reactive oxygen species production was also decreased by the introduction of NADH oxidase, resulting in a significant increase in the growth of T. glabrata under hyperosmotic stress conditions (3824 mOsmol/kg). The results indicated that the osmotolerance of cells can be enhanced by manipulating water‐production pathways. Copyright © 2009 John Wiley & Sons, Ltd.
Expression of Paracoccidioides brasiliensis CHS3 in a Saccharomyces cerevisiae chs3 null mutant demonstrates its functionality as a chitin synthase gene
Authors: Barreto Laura , Sorais Françoise , Salazar Victor , San‐Blas Gioconda , Niño‐Vega Gustavo A.
Published: December 2009

We report the isolation and sequencing of CHS3, a gene that encodes one of several chitin synthases in Paracoccidioides brasiliensis, a medically important fungus restricted geographically to Latin America. The gene contains a single open reading frame of 3817 bp with two introns (71 and 86 bp) and encodes a 1220 amino acid polypeptide with high similarity to other fungal chitin synthases. Northern analysis reveals a high expression of CHS3 in the pathogenic yeast‐like phase of the fungus and at the end of the mycelium–yeast transition. Expression of P. brasiliensis CHS3 in a Saccharomyces cerevisiae chs3 null mutant enhanced calcofluor white staining in parallel to an increase in total chitin synthase activity and chitin content in its cell wall. The sequence of P. brasiliensis CHS3 is available at the GenBank database under Accession No. AF107623.2. Copyright © 2009 John Wiley & Sons, Ltd.
Addressing the Global Burden of Surgical Disease: Proceedings from the 2nd Annual Symposium at the American College of Surgeons
Authors: Perkins R. Serene , Casey Kathleen M. , McQueen K. A. Kelly
Published: December 2009

In the past decade, interest in surgery as a means to improve public health and engage in international service has increased significantly. International organizations, academic institutions, professional associations, and humanitarian aid organizations recognize that disparate access to surgical care affects global health and they have recently joined forces to address access to surgical care. Current initiatives focus on quantitatively defining surgical disparity, prioritizing a surgical agenda, and developing economically sustainable models for health care assistance, training, and delivery. The Global Burden of Surgical Disease Working Group (GBoSD WG) strives to (1) quantitatively define global disparity in surgical care; (2) assess unmet surgical need; (3) identify priorities; (4) develop sustainable models for improved health care delivery; and (5) advocate for a surgical presence within the global public health agenda. This article formally introduces the GBoSD Working Group and papers presented during the 2009 Symposium at the American College of Surgeons in Chicago.
Pain as the Only Consistent Sign of Acute Appendicitis: Lack of Inflammatory Signs Does Not Exclude the Diagnosis
Authors: Monneuse Olivier , Abdalla S. , Pilleul F. , Hervieu V. , Gruner L. , Tissot E. , Barth X.
Published: December 2009

Background

The clinical diagnosis of acute appendicitis in adults remains tricky, but radiological examinations are very helpful to determine the diagnosis even when the adult patient presents atypically. This study was designed to quantify the proportion of patients with a preoperative diagnosis of acute appendicitis that had isolated right lower quadrant pain without biological inflammatory signs and then to determine which imaging examination led to the determination of the diagnosis.

Methods

In this monocentric study based on retrospectively collected data, we analyzed a series of 326 patients with a preoperative diagnosis of acute appendicitis and isolated those who were afebrile and had isolated right lower quadrant pain and normal white blood cell counts and C‐reactive protein levels. We determined whether the systematic ultrasonography examination was informative enough or a complementary intravenous contrast media computed tomography scan was necessary to determine the diagnosis, and whether the final pathological diagnosis fit the preoperative one.

Results

A total of 15.6% of the patients with a preoperative diagnosis of acute appendicitis had isolated rebound tenderness in the right lower quadrant, i.e., they were afebrile and their white blood cell counts and C‐reactive protein levels were normal. In 96.1% of the cases, the ultrasonography examination, sometimes complemented by an intravenous contrasted computed tomography scan if the ultrasonography result was equivocal, fit the histopathological diagnosis of acute appendicitis.

Conclusions

The diagnosis of acute appendicitis cannot be excluded when an adult patient presents with isolated rebound tenderness in the right lower quadrant even without fever and biological inflammatory signs. In our study, ultrasonography and computed tomography were very helpful when making the final diagnosis.
Brief report: Emotion regulation and coping as moderators in the relationship between personality and self‐injury
Authors: Hasking Penelope A. , Coric Sarah J. , Swannell Sarah , Martin Graham , Thompson Holly Knox , Frost Aaron D.J.
Published: December 2009

Self‐injury without conscious suicidal intent is an increasingly prevalent phenomenon particularly among adolescent populations. This pilot study examined the extent and correlates of self‐injurious behaviour in a school population sample of 393 adolescents (aged 13–18 years) using a self‐report questionnaire. Specifically, we aimed to determine whether personality was related to self‐injury and whether this relationship was moderated by emotion regulation or coping strategies. Few personality and coping variables were directly related to self‐injury after controlling for age and psychopathology. However the relationship between personality and self‐injury was moderated by coping skills and emotion regulation. We suggest future research explore these relationships in order to determine the role of coping skills and emotional regulation training in prevention of self‐injury.
Neuronal hyperactivity at the spinal cord and periaqueductal grey during painful diabetic neuropathy: Effects of gabapentin
Authors: Morgado Carla , Terra Patrícia Pereira , Tavares Isaura
Published: December 2009

Painful diabetic neuropathy may be due to impairments in descending modulation of nociceptive transmission at the spinal cord. In the present study, streptozotocin diabetic rats (STZ rats) with neuropathic symptoms (mechanical hypersensitivity) were used to perform a time‐course evaluation of neuronal activity at the spinal dorsal horn and at the periaqueductal grey matter (PAG), a major brainstem area of pain modulation. The expression of Fos protein, a marker of nociceptive activation, progressively increased at the spinal dorsal horn at 4 and 10 weeks. At the PAG, increases in Fos expression were detected until the 4th week, with a reversal to baseline values at 10 weeks in all areas except the ventrolateral PAG. Co‐localisation of Fos with NeuN ascertained the neuronal nature of Fos‐expressing cells at the spinal cord and PAG. Four weeks after diabetes induction, the effects of gabapentin (i.p. injection of 50 mg/kg, daily during 3 days) were assessed. Gabapentin decreased Fos expression at the spinal cord and PAG and reversed mechanical hypersensitivity. The present study shows that diabetic neuropathy is accompanied by a progressive increase of the spontaneous neuronal activity at the spinal cord. Changes in descending modulation of nociceptive transmission from the PAG are likely to occur during diabetic neuropathy, probably with exacerbation of facilitatory actions. The effects of gabapentin in reversing the behavioural signs of diabetic neuropathy and neuronal hyperactivity in the spinal cord and PAG reinforce the central causes of diabetic neuropathy and point to the central targets of the drug.
Mu‐opioid receptors are not necessary for nortriptyline treatment of neuropathic allodynia
Authors: Bohren Yohann , Karavelic Dzenan , Tessier Luc‐Henri , Yalcin Ipek , Gavériaux‐Ruff Claire , Kieffer Brigitte L. , Freund‐Mercier Marie‐José , Barrot Michel
Published: December 2009

Tricyclic antidepressants (TCAs) are among the first line treatments clinically recommended against neuropathic pain. However, the mechanism by which they alleviate pain is still unclear. Pharmacological and genetic approaches evidenced a critical role of delta‐opioid receptors (DORs) in the therapeutic action of chronic TCA treatment. It is however unclear whether mu‐opioid receptors (MORs) are also necessary to the pain‐relieving action of TCAs. The lack of highly selective MOR antagonists makes difficult to conclude based on pharmacological studies. In the present work, we thus used a genetic approach and compared mutant mice lacking MORs and their wild‐type littermates. The neuropathy was induced by unilateral sciatic nerve cuffing. The threshold for mechanical response was evaluated using von Frey filaments. MOR‐deficient mice displayed the same baseline for mechanical sensitivity as their wild‐type littermates. After sciatic nerve cuffing, both wild‐type and MOR‐deficient mice displayed an ipsilateral mechanical allodynia. After about 10 days of treatment, nortriptyline suppressed this allodynia in both wild‐type and MOR‐deficient mice. MORs are thus not critical for nortriptyline action against neuropathic pain. An acute injection of the DOR antagonist naltrindole induced a relapse of neuropathic allodynia in both wild‐type and MOR‐deficient mice, thus confirming the critical role of DORs in nortriptyline action. Moreover, morphine induced an acute analgesia in control and in neuropathic wild‐type mice, but was without effect in MOR‐deficient mice. While MORs are crucial for morphine action, they are not critical for nortriptyline action. Our results highlight the functional difference between DORs and MORs in mechanisms of pain relief.
Stability of lipid domains
Authors: García-Sáez Ana J. , Schwille Petra
Published: December 2009

Membranes with simple lipid composition exhibit complex phase behavior. Ordered and disordered liquid phases can coexist in cholesterol‐containing membranes with lipid compositions resembling biological membranes and at physiological temperatures. Research during the last years suggests that these lipid domains play a role in the organization of biological membranes. Understanding the principles that govern the formation and stability of lipid domains is of great importance to build a model that properly describes membrane structure and function. In this review, we describe the current knowledge of the chemical and physical basis of lipid domains and its application to biological membranes.
Autophagy in the fission yeast Schizosaccharomyces pombe
Authors: Mukaiyama Hiroyuki , Nakase Mai , Nakamura Taro , Kakinuma Yoshimi , Takegawa Kaoru
Published: December 2009

Autophagy is a non‐selective degradation process in eukaryotic cells. The genome sequence of the fission yeast Schizosaccharomyces pombe has revealed that many of the genes required for autophagy are common between the fission yeast and budding yeast, suggesting that the basic machinery of autophagy is conserved between these species. Autophagy in fission yeast is specifically induced by nitrogen starvation based on monitoring a GFP–Atg8p marker. Upon nitrogen starvation, fission yeast cells exit the vegetative cell cycle and initiate sexual differentiation to produce spores. Most of the nitrogen used for de novo protein synthesis during sporulation derives from the autophagic protein degradation system. This review focuses on the recent advances in the role of autophagy in fission yeast.
The urokinase receptor: Focused cell surface proteolysis, cell adhesion and signaling
Authors: Blasi Francesco , Sidenius Nicolai
Published: December 2009

uPAR is highly expressed during tissue reorganization, inflammation, and in virtually all human cancers. Since its discovery, in vitro and in vivo models, as well as retrospective clinical studies have shown that over‐expression of components of the uPA/uPAR‐system correlates with increased proliferation, migration, and invasion affecting the malignant phenotype of cancer. uPAR regulates the cells–extracellular matrix interactions promoting its degradation and turnover through the plasminogen activation cascade.
Roles of the intramolecular regions of FE65 in its trans‐accumulation and in p53 stabilization in the nuclear matrix of osmotically stressed cells
Authors: Kawai Tomoko , Nakaya Tadashi , Suzuki Toshiharu
Published: December 2009

The neural adaptor protein FE65 interacts with the amyloid β‐protein precursor (APP). In osmotically stressed cells, the membrane APP‐tethered FE65 is released into the cytoplasm and translocates to the nuclear matrix, where it stabilizes p53 via a non‐canonical pathway. In this study, we found that the second phosphotyrosine interaction domain (PI2) of FE65 mediated its trans‐accumulation in the nuclear matrix of osmotically stressed cells. The carboxyl‐terminal half of FE65, which contains the PI2 domain, failed to stabilize p53, suggesting that the amino‐terminal half of the protein plays an important role in the stabilization of p53 in osmotically stressed cells.
CLC transport proteins in plants
Authors: Zifarelli G. , Pusch M.
Published: December 2009

Other CLC homologues have been cloned in Arabidopsis, tobacco, rice and soybean.
Flavones suppress type I IL‐4 receptor signaling by down‐regulating the expression of common gamma chain
Authors: Yamashita Shuya , Yamashita Tatsunori , Yamada Koji , Tachibana Hirofumi
Published: December 2009

Immunoglobulin E (IgE) production is induced by interleukin (IL)‐4 signaling mediated by type I IL‐4 receptor (IL‐4R) in B cells. We found that flavones inhibited IL‐4‐induced ε germline transcription which is essential for IgE class switching, and the phosphorylation of signal transducer and activator of transcription 6, janus kinase 3, and IL‐4Rα, whereas IL‐4 signaling mediated through type II IL‐4R was unaffected by flavones. Furthermore, flavones reduced the expression of common gamma chain, a characteristic constituent subunit of type I IL‐4R, suggesting that flavones suppress type I IL‐4R signaling.
Structure of the GTPase and GDI domains of FeoB, the ferrous iron transporter of Legionella pneumophila
Authors: Petermann Nele , Hansen Guido , Schmidt Christian L. , Hilgenfeld Rolf
Published: December 2009

Prokaryotic pathogens have developed specialized mechanisms for efficient uptake of ferrous iron (Fe2+) from the host. In Legionella pneumophila, the causative agent of Legionnaires’ disease, the transmembrane GTPase FeoB plays a key role in Fe2+ acquisition and virulence. FeoB consists of a membrane‐embedded core and an N‐terminal, cytosolic region (NFeoB). Here, we report the crystal structure of NFeoB from L. pneumophila, revealing a monomeric protein comprising two separate domains with GTPase and guanine‐nucleotide dissociation inhibitor (GDI) functions. The GDI domain displays a novel fold, whereas the overall structure of the GTPase domain resembles that of known G domains but is in the rarely observed nucleotide‐free state.
Prenatal diclofenac sodium administration increases the number of Purkinje cells in female rats: a stereological study
Authors: Odaci Ersan , Cihan Omer Faruk , Aslan Huseyin , Ragbetli Murat Cetin , Kaplan Suleyman
Published: December 2009

Diclofenac sodium (DS) may affect the number of Purkinje cells in the developing cerebellum since DS can easily be transported from the maternal to the fetal physiological system during the pregnancy. In the present study, the effects of prenatal exposure to DS on the number of Purkinje cells in the cerebellum of 4‐week‐old (4W‐old) and 20‐week‐old (20W‐old) female rats were investigated. There were two main groups: the drug‐treated group (DTG) and the control group (CG). Beginning from the 5th day after mating for a period of 15 days, a daily dose of 1 mg/kg of DS (Voltaren, 75 mg/3 ml ampul, Novartis, Mefar Ilaç Sanayi A.S., Kartal, İstanbul, Turkey) was intraperitoneally injected in the DTG of pregnant rats. In contrast, a daily dose of 1 ml/kg of isotonic saline was intraperitoneally administered to the CG of pregnant rats during the same period. After spontaneous delivery, female offspring were obtained, and the main groups’ offspring were divided into two subgroups as a 4W‐old group and a 20W‐old group. Therefore, there were four groups at the end of the experiment: the 4W‐old DTG and the CG, and the 20W‐old DTG and the CG. At the end of 4W and 20W, offspring were perfused, their brains were dissected, and the number of cells estimated via the optical fractionator technique. Our results showed that while the total number of Purkinje cells in the cerebellum of offspring of DT 20W‐old female rats was significantly higher than that of the CG, there was no significant difference between the 4W‐old DTG and the control groups. Therefore, it could be suggested that DS administration during the prenatal period increases the number of Purkinje cells in the cerebellum of a developing female rat throughout postnatal 20W.
Assessing hydrological alterations at multiple temporal scales: Adige River, Italy
Authors: Zolezzi G. , Bellin A. , Bruno M. C. , Maiolini B. , Siviglia A.
Published: December 2009

Hydrological alteration is one of the major threats to the integrity and functioning of riverine ecosystems. We propose to analyze such alterations by means of three approaches: the well‐established range of variability approach (RVA), wavelet transform analysis (WT), and a combination of the two. This allows us to separate the most relevant scales of variability and to detect their alteration independently; such information cannot be provided by purely statistical methods like RVA. We show the advantages of this multiple approach through the analysis of two streamflow data sets of the Adige River at Trento, northeastern Italy: a daily streamflow record spanning from 1923 to 2006, and a record of instantaneous measurements with time step of 15 min from 2002 to 2006. Results suggest that starting from the 1960s, after the construction of the reservoirs currently in operation, a progressive flattening occurred in the hydrograph, which attenuated the amplitude of seasonal variations. This negative tendency worsened in the last few years, possibly as an effect of a reduction in winter snowfall. Wavelet analysis shows that hydroelectric production caused the high‐frequency components of the signal to increase in amplitude and number, with fairly regular weekly and daily oscillations and sharp transitions. The whole spectrum of low flows is significantly altered. This alteration of the natural flow has adverse consequences on the ecological integrity of the ecosystem. Use of the range of variability approach, the wavelet transform analysis, and a new methodology which integrates both allows a better separation between natural and human‐induced effects at ecologically relevant scales of variability, thereby identifying changes and trends due to hydropower management.
The 2009–2010 El Niño: Hydrologic Relief to U.S. Regions
Authors: Tootle Glenn A. , Piechota Thomas C. , Aziz Oubeidillah , Miller W. Paul , Lakshmi Venkat , Dracup John A. , Jerla Carly
Published: December 2009

Current forecasts by the U.S. National Oceanic and Atmospheric Administration (NOAA) are that the Pacific Ocean will experience El Niño conditions in late 2009 and into 2010. These forecasts are similar to past El Ni˜o events in 1972–1973, 1982–1983, 1986–1987, and 2002–2003.

Evaluating the hydrologic conditions for these past El Niño events reveals that during these times, surface water supply conditions improved in many parts of the United States, including the Southeast, Midwest, and Southwest. At the same time, the Pacific Northwest and other specific regions of the United States experienced below‐average water supply conditions. This is consistent with the long‐established linkages between oceanic‐atmospheric phenomena, El Niño, and streamflow [e.g., Kahya and Dracup, 1993; Tootle et al., 2005].
Active‐Source Seismic Experiment Confirms the Magma Pathway of Mount Asama, Japan
Authors: Aoki Yosuke , Takeo Minoru , Morita Yuichi , Tsutsui Tomoki
Published: December 2009

Large volcanic eruptions result from the ejection of magma transported from depth. How the magma is transported to the surface is one of the fundamental questions in understanding how a volcano works. A way to address this question is to explore the seismic structures of volcanoes.

One volcano that is well surveyed and instrumented through a variety of global positioning system and seismic networks is Japan's Mount Asama. Because of this, scientists were able to conduct an active‐source seismic experiment on this volcano with the goal of mapping volcanic conduits (see Figure 1).
New User Facility for Environmental Sensing
Authors: Tyler Scott , Selker John
Published: December 2009

Hydrologic instrumentation is undergoing a transformative shift in its ability to concurrently measure scales from centimeters to kilometers [e.g., Selker et al., 2006]. To rapidly distribute and incorporate these advances in the Earth and hydrologic sciences, the U.S. National Science Foundation's Earth Sciences Instrumentation and Facilities Program launched in September 2009 a community‐accessible instrument facility for distributed temperature sensing (DTS) and wireless networked environmental sensing.

DTS systems for the facility use laser‐induced Raman backscatter (spectrally shifted scattered light whose intensity can be related to the thermal state of the optical fiber) to measure the distribution of temperatures along fiber‐optic cables up to 30 kilometers long. The DTS systems can measure temperatures along fiber‐optic cable with spatial resolution of less than 1 meter and with temperature resolution of ±0.01°C. In contrast to “single point in space” measurements of environmental temperatures or “single point in time” remote sensing of temperatures, DTS provides the opportunity to continuously monitor temperatures of air, water, soil, or snow at high spatial and temporal frequency without the need for a large network of measurement systems.
Earth Sciences Push Radiative Transfer Theory: 2009 International Conference on Advances in Mathematics, Computational Methods, and Reactor Physics; Saratoga Springs, New York, 4–7 May 2009
Authors: Davis Anthony , Mishchenko Michael
Published: December 2009

The theories of radiative transfer and particle—particularly neutron—transport are grounded in distinctive microscale physics that deals with either optics or particle dynamics. However, it is not practical to track every wave or particle in macroscopic systems, nor do all of these details matter. That is why Newton's laws, which describe individual particles, are replaced by those of Euler, Navier‐Stokes, Maxwell, Boltzmann, Gibbs, and others, which describe the collective behavior of vast numbers of particles. And that is why the radiative transfer (RT) equation is used to describe the flow of radiation through geophysical‐scale systems, leaving to Maxwell's wave equations only the task of providing the optical properties of the medium, be it air, water, snow, ice, or biomass. Interestingly, particle transport is determined by the linear transport equation, which is mathematically identical to the RT equation, so geophysicists and nuclear scientists are interested in the same mathematics and computational techniques.
Improving Environmental Projections in the High Mountains of Northern Eurasia: International Workshop on the Northern Eurasia High Mountain Ecosystems; Bishkek, Kyrgyzstan, 9–13 September 2009
Authors: Groisman Pavel , Aizen Vladimir
Published: December 2009

The northern Eurasia high mountains, particularly in dry regions of Central Asia, are critically important because they are the source of the water supply for the densely populated lowlands. These regions are highly vulnerable to climatic and environmental changes. Global warming, current and future expected retreat of seasonal snow cover and glaciers, and changes in precipitation pattern and type significantly affect river runoff, permafrost, and groundwater. Moreover, the majority of mountain regions in northern Eurasia are characterized by growing anthropogenic pressure that causes harmful feedback, including desertification of lowlands; wind erosion; contamination of the atmosphere, surface waters, and groundwaters; reduction in crop yield; and increasing human mortality rates.
A Crash Course in Science Radio Reporting
Authors: Schielke Erika
Published: December 2009

This past summer, 5 weeks after defending my doctoral dissertation, I traded my lab bench and field sampling gear for a radio reporter's recorder and a microphone, and I headed west. As a graduate student at Yale University in New Haven, Conn., I had seen great science going on all around me, but the public was unaware of most of it. Having dabbled in science writing while finishing my Ph.D. in ecology and evolutionary biology, I was looking for ways to gain more experience in science communication and even had been considering pursuing a career in science reporting.

Then a remarkable opportunity opened up that took me to Greeley, Colo., covering science stories at KUNC, a National Public Radio affiliate, for 10 weeks this past summer.
Deep mantle subduction flux
Authors: Porter Katherine A. , White William M.
Published: December 2009

We assess the flux of incompatible trace elements into the deep mantle in the Aleutian, Central America, Izu‐Bonin, Kurile, Lesser Antilles, Mariana, Sunda, and Tonga subduction zones. We use a simple mass balance approach in which we assume that all of the material lost from the subducting crust and sediment (the “slab”) is incorporated into the magmas erupted above the subduction zone, and we use these assumptions to calculate a residual slab composition. The calculated residual slabs are enriched in incompatible elements compared to mid‐ocean ridge basalts and highly enriched compared to primitive or depleted mantle. Almost all of the subducted Nb, Ta, and intermediate and heavy rare earths survive into the deep mantle, as do most of the light rare earths. On average, 73% of Th and Pb, 74% of K, 79% of U, 80% of Rb, 80% of Sr, and 82% of Ba survive into the deep mantle. Pb/Ce ratios are systematically lower, and Nb/U ratios are systematically higher, in the deep mantle flux than they are in the flux of material into the trench. Nevertheless, most residual slabs have Pb/Ce and Nb/U ratios outside the typical mantle range. Changes to U/Pb and Th/U ratios tend to be small and are not systematic. Rb/Sr ratios significantly decrease in some subduction zones but increase in others. In contrast, Sm/Nd ratios increase by small but significant amounts in most arcs. Based on these results, we attempt to predict the Sr, Nd, and Pb composition of anciently recycled material now in the mantle. We find that such material would most resemble enriched mantle II–type oceanic island basalts (OIB). None of our calculated residual slabs would evolve to Sr‐Nd‐Pb isotopic compositions similar to either high 238U/204Pb or enriched mantle I. The range of Sr and Pb isotope ratios in anciently recycled material is similar to that seen in modern OIB, but Nd isotopic compositions do not range to ɛNd values as low as those in some modern OIB. Neither radiogenic nor unradiogenic Pb isotope compositions can be exclusively associated with recycled material.
Interactions between deformation and fluids in the frontal thrust region of the NanTroSEIZE transect offshore the Kii Peninsula, Japan: Results from IODP Expedition 316 Sites C0006 and C0007
Authors: Screaton E. , Kimura G. , Curewitz D. , Moore G. , Chester F. , Fabbri O. , Fergusson C. , Girault F. , Goldsby D. , Harris R. , Inagaki F. , Jiang T. , Kitamura Y. , Knuth M. , Li C.‐F. , Liljedahl L. Claesson , Louis L. , Milliken K. , Nicholson U. , Riedinger N. , Sakaguchi A. , Solomon E. , Strasser M. , Su X. , Tsutsumi A. , Yamaguchi A. , Ujiee K. , Zhao X.
Published: December 2009

Integrated Ocean Drilling Program (IODP) Expedition 316 Sites C0006 and C0007 examined the deformation front of the Nankai accretionary prism offshore the Kii Peninsula, Japan. In the drilling area, the frontal thrust shows unusual behavior as compared to other regions of the Nankai Trough. Drilling results, integrated with observations from seismic reflection profiles, suggest that the frontal thrust has been active since ∼0.78–0.436 Ma and accommodated ∼13 to 34% of the estimated plate convergence during that time. The remainder has likely been distributed among out‐of‐sequence thrusts further landward and/or accommodated through diffuse shortening. Unlike results of previous drilling on the Nankai margin, porosity data provide no indication of undercompaction beneath thrust faults. Furthermore, pore water geochemistry data lack clear indicators of fluid flow from depth. These differences may be related to coarser material with higher permeability or more complex patterns of faulting that could potentially provide more avenues for fluid escape. In turn, fluid pressures may affect deformation. Well‐drained, sand‐rich material under the frontal thrust could have increased fault strength and helped to maintain a large taper angle near the toe. Recent resumption of normal frontal imbrication is inferred from seismic reflection data. Associated décollement propagation into weaker sediments at depth may help explain evidence for recent slope failures within the frontal thrust region. This evidence consists of seafloor bathymetry, normal faults documented in cores, and low porosities in near surface sediments that suggest removal of overlying material. Overall, results provide insight into the complex interactions between incoming materials, deformation, and fluids in the frontal thrust region.
Volcanic and geochemical evolution of the Teno massif, Tenerife, Canary Islands: Some repercussions of giant landslides on ocean island magmatism
Authors: Longpré Marc‐Antoine , Troll Valentin R. , Walter Thomas R. , Hansteen Thor H.
Published: December 2009

Large‐scale, catastrophic mass wasting is a major process contributing to the dismantling of oceanic intraplate volcanoes. Recent studies, however, have highlighted a possible feedback relationship between flank collapse, or incipient instability, and subsequent episodes of structural rearrangement and/or renewed volcano growth. The Teno massif, located in northwestern Tenerife (Canary Islands), is a deeply eroded Miocene shield volcano that was built in four major eruptive phases punctuated by two lateral collapses, each removing >20–25 km3 of the volcano's north flank. In this paper, we use detailed field observations and petrological and geochemical data to evaluate possible links between large‐scale landslides and subsequent volcanism/magmatism during Teno's evolution. Inspection of key stratigraphic sequences reveals that steep angular unconformities, relics of paleolandslide scars, are marked by polymict breccias. Near their base, these deposits typically include abundant juvenile pyroclastic material, otherwise scarce in the region. While some of Teno's most evolved, low‐density magmas were produced just before flank collapses, early postlandslide lava sequences are characterized by anomalously high proportions of dense ankaramite flows, extremely rich in clinopyroxene and olivine crystals. A detailed sampling profile shows transitions from low‐Mg # lavas relatively rich in SiO2 to lavas with low silica content and comparatively high Mg # after both landslides. Long‐term variations in Zr/Nb, normative nepheline, and La/Lu are coupled but do not show a systematic correlation with stratigraphic boundaries. We propose that whereas loading of the growing precollapse volcano promoted magma stagnation and differentiation, the successive giant landslides modified the shallow volcano‐tectonic stress field at Teno, resulting in widespread pyroclastic eruptions and shallow magma reservoir drainage. This rapid unloading of several tens of km3 of near‐surface rocks appears to have upset magma differentiation processes, while facilitating the remobilization and tapping of denser ankaramite magmas that were stored in the uppermost mantle. Degrees of mantle melting coincidently reached a maximum in the short time interval between the two landslides and declined shortly after, probably reflecting intrinsic plume processes rather than a collapse‐induced influence on mantle melting. Our study of Teno volcano bears implications for other oceanic volcanoes where short‐term compositional variations may also directly relate to major flank collapse events.
Depth dependent seismic scattering attenuation in the Nuevo Cuyo region (southern central Andes)
Authors: Badi G. , Del Pezzo E. , Ibanez J. M. , Bianco F. , Sabbione N. , Araujo M.
Published: December 2009

In the present work we separated intrinsic from scattering attenuation coefficients both for the crust and the upper mantle in the tectonically highly active areas of the Southern‐Central Andes ‐ Nuevo Cuyo region, analyzing two groups of earthquakes, well separated in depth. This region is characterized by the presence of flat subduction. We apply MLTWA (Multiple Lapse Time Window Analysis), coda normalization and Q‐coda techniques to measure the scattering and intrinsic attenuation coefficient and the total Q for S waves. We find that intrinsic attenuation does not decrease with depth whereas scattering attenuation is higher in the crust than in the upper mantle, and that intrinsic attenuation predominates over scattering attenuation. We interpret this observation in terms of the release of water and other fluids into the overlying lithosphere due to the dynamics of the subduction process, in agreement with most of the prevalent geodynamic models.
Two‐dimensional hybrid code simulation of electromagnetic ion cyclotron waves in a dipole magnetic field
Authors: Hu Y. , Denton R. E.
Published: December 2009

Proton temperature anisotropy (T > 1) with sufficiently high will drive the electromagnetic ion cyclotron (EMIC) instability. A two‐dimensional hybrid code is employed to simulate the EMIC waves in a dipole magnetic field. We initialize the electron‐proton plasma such that the MHD equilibrium J × B = − · is satisfied for the parallel force, while it is only satisfied along the magnetic equator for the perpendicular force. A high temperature ratio T = 9 and low plasma beta β = 0.1 are used to lessen the effects of nonequilibrium off the equator. The plasma is more unstable to the EMIC waves along the magnetic equator where the temperature ratio is high and the plasma β is low. There, waves are generated with dominant left‐hand polarization with the expected EMIC wave frequencies based on linear theory. These waves propagate along the magnetic field toward the ionosphere; and the inhomogeneity of the magnetic field causes the waves in the low L shell region to travel faster than those in the high L shell, so that the wavefronts turn oblique to the local magnetic field. When the wave vector turns perpendicular to the magnetic field at high magnetic latitudes, the initially left‐hand waves become linearly polarized. The linear polarization of the EMIC waves is consistent with some observations and with ray tracing results for reflected waves. We also introduce resistive layers to damp the waves near the boundaries to reduce the waves that are reflected by the boundary condition. The power spectra indicate that there is a radial propagation of wave energy with a group speed equal to about 0.1 times the equatorial Alfvén speed. Additionally, we find that there is a radial coherence length equal to about 10 associated with the EMIC wave structure.
Measurements of quasi‐trapped electron and positron fluxes with PAMELA
Authors: Adriani O. , Barbarino G. , Bazilevskaya G. A. , Bellotti R. , Boezio M. , Bogomolov E. A. , Bonechi L. , Bongi M. , Bonvicini V. , Borisov S. V. , Bottai S. , Bruno A. , Cafagna F. S. , Campana D. , Carbone R. , Carlson P. , Casolino M. , Castellini G. , Consiglio L. , De Pascale M. P. , De Santis C. , De Simone N. , Di Felice V. , Galper A. M. , Gillard W. , Grishantseva L. A. , Jerse G. , Hofverberg P. , Karelin A. V. , Koldashov S. V. , Krutkov S. Y. , Kvashnin A. N. , Leonov A. A. , Malakhov V. V. , Malvezzi V. , Marcelli L. , Mayorov A. G. , Menn W. , Mikhailov V. V. , Mocchiutti E. , Monaco A. , Mori N. , Nikonov N. N. , Osteria G. , Papini P. , Pearce M. , Picozza P. , Pizzolotto C. , Ricci M. , Ricciarini S. B. , Rossetto L. , Ritabrata S. , Runtso M. F. , Simon M. , Sparvoli R. , Spillantini P. , Stozhkov Y. I. , Vacchi A. , Vannuccini E. , Vasilyev G. I. , Voronov S. A. , Wu J. , Yurkin Y. T. , Zampa G. , Zampa N. , Zverev V. G.
Published: December 2009

This paper presents precise measurements of the differential energy spectra of quasi‐trapped secondary electrons and positrons and their ratio between 80 MeV and 10 GeV in the near‐equatorial region (altitudes between 350 km and 600 km). Latitudinal dependences of the spectra are analyzed in detail. The results were obtained from July until November 2006 onboard the Resurs‐DK satellite by the PAMELA spectrometer, a general purpose cosmic ray detector system built around a permanent magnet spectrometer and a silicon‐tungsten calorimeter.
Surface currents during anomalous upwelling seasons off central California
Authors: Kaplan David M. , Halle Chris , Paduan Jeff , Largier John L.
Published: December 2009

An extensive spatiotemporal surface currents data set from central California is used to examine in detail 2 extreme years in the California Current. The year 2006 is characterized by an extended period of calm winds during the critical early months of the upwelling season (April and May). This leads to little or no upwelling over this period, essentially delaying the onset of the upwelling season. The year 2007 is characterized by extremely strong alongshore wind stress during the first quarter of the year and during the early part of the upwelling season. This produced monthly mean alongshore current velocities over the midshelf for April 2007 in excess of 0.7 m s−1, which has not been previously observed in this region for periods of more than a few days since the installation of the HF radar instruments in 2001. Both of these extremes appear to have had important consequences for the coastal ecosystem that have been documented elsewhere, including the collapse of parts of the trophic web (2006) and the presence of large quantities of water of deep origin over the continental shelf (2007). Understanding and describing circulation and transport patterns during these extremes is important in light of predictions from global climate change, which may cause these extreme conditions to occur more frequently.
Recent changes in Arctic sea ice melt onset, freezeup, and melt season length
Authors: Markus Thorsten , Stroeve Julienne C. , Miller Jeffrey
Published: December 2009

In order to explore changes and trends in the timing of Arctic sea ice melt onset and freezeup, and therefore melt season length, we developed a method that obtains this information directly from satellite passive microwave data, creating a consistent data set from 1979 through present. We furthermore distinguish between early melt (the first day of the year when melt is detected) and the first day of continuous melt. A similar distinction is made for the freezeup. Using this method we analyze trends in melt onset and freezeup for 10 different Arctic regions. In all regions except for the Sea of Okhotsk, which shows a very slight and statistically insignificant positive trend (0.4 d decade−1), trends in melt onset are negative, i.e., toward earlier melt. The trends range from −1.0 d decade−1 for the Bering Sea to −7.3 d decade−1 for the East Greenland Sea. Except for the Sea of Okhotsk all areas also show a trend toward later autumn freeze onset. The Chukchi/Beaufort seas and Laptev/East Siberian seas observe the strongest trends with 7 d decade−1. For the entire Arctic, the melt season length has increased by about 20 days over the last 30 years. Largest trends of over 10 d decade−1 are seen for Hudson Bay, the East Greenland Sea, the Laptev/East Siberian seas, and the Chukchi/Beaufort seas. Those trends are statistically significant at the 99% level.