bluuebunny/crossref_metadata_2025 huggingface dataset:
Risk‐Reduction Surgery Decisions in High‐Risk Women Seen for Genetic Counseling
Authors: Ray Jessica A. , Loescher Lois J. , Brewer Molly
Published: December 2005

Women at greatest risk for hereditary breast and ovarian cancer may consider prophylactic removal of breasts or ovaries as a risk‐reduction measure. This report describes uptake of risk‐reduction mastectomy (RRM), risk‐reduction oophorectomy (RRO), and related factors in 62 high‐risk women who received genetic counseling. Seven (11%) participants underwent RRM and 13 (21%) underwent RRO. Of these women, 37% did not have BRCA testing, suggesting other factors influence decisions to undergo surgery. Women who had indicated (pre‐genetic counseling) their intent not to have surgery chose not to have surgery. Information received during genetic counseling that women perceived as being most important for influencing risk‐reduction surgery decisions was BRCA test result (positive or negative), followed by discussion of family cancer history. Reasons for indecision about risk‐reduction surgery included genetic testing results, concerns about surgery, timing in life, and early menopause. The findings enhance our understanding of information that is helpful to women considering this surgery.
“SLANG”—Sensitive Language and the New Genetics—an Exploratory Study
Authors: Hodgson J. , Hughes E. , Lambert C.
Published: December 2005

SLANG—Sensitive Language and the New Genetics—is a concept that arose out of informal discussions between a number of interested parties, both consumers and professionals, who were becoming increasingly uneasy with some of the language commonly used in medical genetics. Some language choices were felt by the authors to be inappropriate for a variety of reasons. Poor language choice may impede an individual's understanding of a genetic condition or important medical information and the chosen words themselves may simply be perceived as discriminatory and even offensive.

SLANG is an important concept to explore partly because literature in this area confirms that language choices in medical settings can be of great significance to both patients and families. Studies have shown how language choices impact on professional practice by, as one example, changing the intended meaning of medical information and affecting individual perception of risk and choice which, in turn, may affect individual or familial well‐being. In addition language choice has the power to affect how individuals perceive themselves and are viewed by others. This paper presents the results from our pilot study and discusses the implications for health professionals with particular reference to medical genetics settings.
Psychological Adjustment and Knowledge About Hereditary Hemochromatosis in a Clinic‐Based Sample: A Prospective Study
Authors: Meiser Bettina , Dunn Stewart , Dixon Jeannette , Powell Lawrie W.
Published: December 2005

This study assessed psychological adjustment and quality of life relative to population‐based norms and knowledge about hereditary hemochromatosis in a sample of 101 patients who attended a hemochromatosis clinic. Participants were assessed prior to their clinic visit, and two weeks and 12 months after attendance, using self‐administered questionnaires. Mean Mental Health Component Scores from the Medical Outcomes Study 36‐Item Short‐Form Health Survey (SF‐36) (45.3, 95% CI 43.2, 47.4) were as compromised as those found amongst stroke victims (45.9, 95% CI 42.8, 49.0) who had participated in a national health survey. Recall of the genetic testing result was less than optimal, in that only 69.3% of those with genetic testing results knew whether they carried one or two mutations. This study demonstrates that patients would benefit from routine assessment of psychological distress and referral to mental health professionals of those whose levels of distress suggest a need for clinical intervention. Results also show that patients may benefit from strategies aimed at improving recall of genetic testing results.
Sequential Down Syndrome Screening: The Importance of First and Second Trimester Test Correlations when Calculating Risk
Authors: Benn Peter , Donnenfeld Alan E.
Published: December 2005

Down syndrome screening can be particularly effective when both first and second trimester tests are performed. However, the counseling of women who have received sequential first and second trimester screening can be problematic. We evaluated an approximation where the post‐test risk from the first trimester screening is used as the new a priori risk for the second trimester screening. The approximation disregards between‐trimester test correlations. The Down syndrome detection rate based on the approximation (90.2%) would be close to that obtained when all correlations were considered (90.8%) but the false positive rate would be 26% higher (3.9% versus 3.1%, respectively). For any particular woman, the use of the approximation could result in highly inaccurate risks. We conclude that the correlations that exist between first and second trimester screening tests preclude the use of second trimester risks derived from the direct product of separate first and second trimester screening. Counseling issues in the delivery of sequential screening are discussed.
Doctor's Expertise and Managing Discrepant Information from Other Sources in Genetic Counseling: A Conversation Analytic Perspective
Authors: Lehtinen Esa , Kääriäinen Helena
Published: December 2005

The study examines a recurrent interactional pattern in genetic counseling. It describes clinical geneticists' responses in situations in which clients have presented information from other sources that is potentially discrepant with information given by the doctor. The data consists of 12 video‐recorded sessions of genetic counseling in Finland, and the method is conversation analysis. There are two primary ways the doctors respond: either they accept the client's information as such, but show that it is not discrepant with the doctor's information, or they reject the client's information. In the latter case they mitigate the ‘wrongness’ of the client's information. The clinical geneticists seem to be working with a dilemma: they need to find a balance between ensuring correct understanding of the information and showing respect for the expertise of others. A particularly complex case is also analyzed and reflected on.
Myelin basic protein, an autoantigen in multiple sclerosis, is selectively processed by human trypsin 4
Authors: Medveczky Péter , Antal József , Patthy András , Kékesi Katalin , Juhász Gábor , Szilágyi László , Gráf László
Published: December 2005

Demyelination, the proteolytic degradation of the major membrane protein in central nervous system, myelin, is involved in many neurodegenerative diseases. In the present in vitro study the proteolytic actions of calpain, human trypsin 1 and human trypsin 4 were compared on lipid bound and free human myelin basic proteins as substrates. The fragments formed were identified by using N‐terminal amino acid sequencing and mass spectrometry. The analysis of the degradation products showed that of these three proteases human trypsin 4 cleaved myelin basic protein most specifically. It selectively cleaves the Arg79‐Thr80 and Arg97‐Thr98 peptide bonds in the lipid bound form of human myelin basic protein. Based on this information we synthesized peptide IVTPRTPPPSQ that corresponds to sequence region 93–103 of myelin basic protein and contains one of its two trypsin 4 cleavage sites, Arg97‐Thr98. Studies on the hydrolysis of this synthetic peptide by trypsin 4 have confirmed that the Arg97‐Thr98 peptide bond is highly susceptible to trypsin 4. What may lend biological interest to this finding is that the major autoantibodies found in patients with multiple sclerosis recognize sequence 85–96 of the protein. Our results suggest that human trypsin 4 may be one of the candidate proteases involved in the pathomechanism of multiple sclerosis.
Efficient delivery of siRNA into cytokine‐stimulated insulinoma cells silences Fas expression and inhibits Fas‐mediated apoptosis
Authors: Burkhardt Brant R. , Lyle Rachel , Qian Keping , Arnold Anne-Sophie , Cheng Henrique , Atkinson Mark A. , Zhang Y. Clare
Published: December 2005

Fas/FasL interactions have been proposed as a potentially important mechanism mediating β‐cell death in type 1 diabetes. Recent investigations suggest RNA interference, afforded by small interfering RNAs (siRNA), can provide specific and robust gene silencing in mammalian cells. The current study attempted to investigate the effects of silencing Fas expression with siRNA on Fas‐mediated apoptosis in mouse insulinoma cells following cytokine incubation. Our results indicate that siRNA is capable of rapid inhibition of cytokine‐induced Fas mRNA production and cell surface Fas protein. A complete suppression of the total Fas protein was only observed after prolonged incubation with siRNA, suggesting a slow turn‐over of Fas protein. Moreover, siRNA significantly inhibited Fas‐mediated β‐cell apoptosis assessed by Caspase‐3 and terminal deoxynucleotidyl transferase biotin‐dUTP nick end labeling assays, the extent of which positively correlated with the level of cell surface Fas. These observations provide additional evidence supporting a role for the Fas‐mediated pathway in β‐cell destruction, and suggest that siRNA targeting Fas may be of therapeutic value in preventing type 1 diabetes and improving islet cell viability in transplantation.
First “hybrid” ligands of vanilloid TRPV1 and cannabinoid CB2receptors and non‐polyunsaturated fatty acid‐derived CB2‐selective ligands
Authors: Appendino Giovanni , Cascio Maria Grazia , Bacchiega Sara , Moriello Aniello Schiano , Minassi Alberto , Thomas Adèle , Ross Ruth , Pertwee Roger , De Petrocellis Luciano , Di Marzo Vincenzo
Published: December 2005

12‐Phenylacetyl‐ricinoleoyl‐vanillamide (phenylacetylrinvanil, PhAR, IDN5890), is an ultra‐potent agonist of human vanilloid TRPV1 receptors also endowed with moderate affinity for human cannabinoid CB2receptors. To improve its CB2affinity and temper its potency at TRPV1, the modification of the polar headgroup and the lipophilic 12‐acylgroup of PhAR was pursued. Replacement of the vanillyl headgroup of PhAR with various aromatic or alkyl amino groups decreased activity at TRPV1 receptors, although the dopamine, cyclopropylamine, 1′‐(R)‐ and 1′‐(S)‐methyl‐ethanolamine, and ethanolamine derivatives retained significant potency (EC5031–126 nM). Within these compounds, the 12‐phenylacetylricinoleyl cyclopropylamide and ethanolamide were the strongest ligands at CB2receptors, withKiof 22 and 44 nM, and 14‐ and >20‐fold selectivity over cannabinoid CB1receptors, respectively. The propyl‐ and allyl‐derivatives also exhibited high affinity at CB2receptors (Ki= 40 and 22 nM, with 40 and >80‐fold selectivity over CB1receptors, respectively), but no activity at TRPV1 receptors. The cyclopropyl‐ and allyl‐derivatives behaved as CB2inverse agonists in the GTP‐γ‐S binding assay. Addition ofpara‐methoxy, ‐tert‐butyl or ‐chlorine groups to the 12‐phenylacetyl moiety of PhAR produced compounds that retained full potency at TRPV1 receptors, but with improved selectivity over CB2or CB1receptors. Thus, the manipulation of PhAR led to the development of the first CB2/TRPV1 dual ligands and of an entirely new class of inverse agonists at CB2receptors. Both types of compounds might find application in the treatment of inflammation, and represent new molecular probes to investigate the endocannabinoid–endovanilloid signalling system.
Cyclin D1 activation through ATF‐2 in Reg‐induced pancreatic β‐cell regeneration
Authors: Takasawa Shin , Ikeda Takayuki , Akiyama Takako , Nata Koji , Nakagawa Kei , Shervani Nausheen J. , Noguchi Naoya , Murakami-Kawaguchi Shoko , Yamauchi Akiyo , Takahashi Iwao , Tomioka-Kumagai Tomoko , Okamoto Hiroshi
Published: December 2005

Regenerating gene product (Reg) is induced in pancreatic β‐cells and acts as an autocrine/paracrine growth factor for regeneration via a cell surface Reg receptor. However, the manner by which Reg induces β‐cell regeneration was unknown. In the present study, we found that Reg increased phospho‐ATF‐2, which binds to −57 to −52 of the cyclin D1 gene to activate the promoter. The Reg/ATF‐2‐induced cyclin D1 promoter activation was attenuated by PI(3)K inhibitors such as LY294002 and wortmannin. In Reg knockout mouse islets, the levels of phospho‐ATF‐2, cyclin D1, and phospho‐Rb were greatly decreased. These results indicate that the Reg–Reg receptor system stimulates the PI(3)K/ATF‐2/cyclin D1 signaling pathway to induce β‐cell regeneration.
Raf‐1 kinase associates with Hepatitis C virus NS5A and regulates viral replication
Authors: Bürckstümmer T. , Kriegs M. , Lupberger J. , Pauli E.K. , Schmittel S. , Hildt E.
Published: December 2005

Hepatitis C virus (HCV) is a positive‐strand RNA virus that frequently causes persistent infection associated with severe liver disease. HCV nonstructural protein 5A (NS5A) is essential for viral replication. Here, the kinase Raf‐1 was identified as a novel cellular binding partner of NS5A, binding to the C‐terminal domain of NS5A. Raf‐1 colocalizes with NS5A in the HCV replication complex. The interaction of NS5A with Raf‐1 results in increased Raf‐1 phosphorylation at serine 338. Integrity of Raf‐1 is crucial for HCV replication: inhibition of Raf‐1 by the small‐molecule inhibitor BAY43‐9006 or downregulation of Raf‐1 by siRNA attenuates viral replication.
Cheltenham Festival 2005
Authors: Conway Paul
Published: January 2006

Cheltenham Festival 2005: John Pickard’s ‘Gaia’ Symphony for brass
Mapping of the heavy ion outflows as seen by IMAGE and multifluid global modeling for the 17 April 2002 storm
Authors: Winglee R. M. , Lewis W. , Lu Gang
Published: December 2005

Multifluid global modeling that includes both light and heavy ion dynamics is used to investigate changes in magnetospheric dynamics produced by enhanced ionospheric outflows for the 17 April 2002 storm. The predicted outflow rates and their effects on the magnetosphere are compared with AMIE and IMAGE/HENA data as a function of relative O+ concentration in the ionosphere. It is shown that O+ can be the dominant species on the dusk side in the inner magnetosphere during the periods of high activity even for ionospheric concentrations as low as 5% as a result of differential heavy ion convection patterns. However, for these low outflow conditions, the cross‐polar cap potential is much larger than that calculated by AMIE. As the O+ ionospheric concentration increases, the heavy outflow rate approaches canonical values, and the effective ionospheric resistivity falls in association with a decrease in cross‐polar cap potential and an increase in the auroral field aligned currents. Within the magnetosphere, the region where the O+ concentration exceeds 50% expands toward the duskside and down the tail. Pressures in excess of 1 nPa can be supported by the enhanced O+ outflows. The presence of these enhanced outflows appears at about the same time and over a similar region to enhancements seen in the HENA 51–180 keV oxygen data. These results provide a direct tie between heavy ionospheric outflows and their energization in the tail and suggest that during this period the heavy ions provide a substantial amount of the plasma required to support the magnetotail current sheet. The model results also show that the enhanced O+ outflow leads to the enhanced exclusion of light ions of both solar wind and ionospheric origin in the plasma sheet, albeit with the light ions experiencing enhanced heating in an O+ dominated current sheet. These results indicate that observed heavy ionospheric outflows and their energetization in the tail have global consequences for the magnetosphere including supporting the dynamics of the tail current sheet during active times and in global circulation including the cross‐polar cap potential and the region 1 and 2 currents.
Effects of the major geomagnetic storms of October 2003 on the equatorial and low‐latitude F region in two longitudinal sectors
Authors: Sahai Y. , Fagundes P. R. , Becker‐Guedes F. , Bolzan M. J. A. , Abalde J. R. , Pillat V. G. , de Jesus R. , Lima W. L. C. , Crowley G. , Shiokawa K. , MacDougall J. W. , Lan H. T. , Igarashi K. , Bittencourt J. A.
Published: December 2005

The intense modifications in the ionosphere‐thermosphere system in the equatorial and low‐latitude regions associated with the dynamic and electrodynamic coupling from high to low latitudes and chemical changes during geomagnetic storms are important space weather issues. In the second half of October 2003, the intense solar activity resulted in one intense and two major geomagnetic storms on 29 and 30 October. In this paper we present and discuss the ionospheric sounding observations carried out from Palmas and São José dos Campos, Brazil (the Brazilian sector), and Ho Chi Minh City, Vietnam, and Okinawa, Japan (the East Asian sector), during these storms. The two sectors are separated by about 12 hours in local time (so while one sector is in daytime, the other one is in nighttime) and provide valuable information related to the storm‐time longitudinal differences. Copious storm‐time changes were observed in both sectors. It should be pointed out that the two longitudinal sectors investigated in the present study clearly show the global nature of the storm‐time effects. However, the responses to the storm‐time effects are also associated with the local time in the two sectors. The present investigations show that there are both similarities and differences in the storm‐time response in the two sectors. During the storm main phases, with sharp decreases of the Dst index, both sectors showed (dusk or dawn periods) fast uplifting of the F layer associated with magnetospheric electric field penetration. Although in the East Asian sector, Ho Chi Minh City and Okinawa are located fairly close in longitude, with only 2 hour difference in local lime, on occasions the storm‐time responses have been very different. Some differences in the latitudinal response of the F region were also observed in the two sectors. Both positive and negative storm phases have been observed at all the four stations. A comparison of the ionospheric parameters obtained from the TIMEGCM model runs and the observed ionospheric parameters at the four stations shows a reasonable agreement during the quiet periods. During the geomagnetic disturbance period, when there were sharp decreases in Dst, some of the observed rapid uplifts of the F region peak heights are not reproduced by the model results. Also, sometimes the model foF2 results differ considerably from the observed foF2 variations. The period investigated represents an extreme storm situation for validation of the model and points to ways in which the model might be improved in the future.
Influence of the seasonal snow cover on the ground thermal regime: An overview
Authors: Zhang Tingjun
Published: December 2005

The presence of seasonal snow cover during the cold season of the annual air temperature cycle has significant influence on the ground thermal regime in cold regions. Snow has high albedo and emissivity that cool the snow surface, high absorptivity that tends to warm the snow surface, low thermal conductivity so that a snow layer acts as an insulator, and high latent heat due to snowmelt that is a heat sink. The overall impact of snow cover on the ground thermal regime depends on the timing, duration, accumulation, and melting processes of seasonal snow cover; density, structure, and thickness of seasonal snow cover; and interactions of snow cover with micrometeorological conditions, local microrelief, vegetation, and the geographical locations. Over different timescales either the cooling or warming impact of seasonal snow cover may dominate. In the continuous permafrost regions, impact of seasonal snow cover can result in an increase of the mean annual ground and permafrost surface temperature by several degrees, whereas in discontinuous and sporadic permafrost regions the absence of seasonal snow cover may be a key factor for permafrost development. In seasonally frozen ground regions, snow cover can substantially reduce the seasonal freezing depth. However, the influence of seasonal snow cover on seasonally frozen ground has received relatively little attention, and further study is needed. Ground surface temperatures, reconstructed from deep borehole temperature gradients, have increased by up to 4°C in the past centuries and have been widely used as evidence of paleoclimate change. However, changes in air temperature alone cannot account for the changes in ground temperatures. Changes in seasonal snow conditions might have significantly contributed to the ground surface temperature increase. The influence of seasonal snow cover on soil temperature, soil freezing and thawing processes, and permafrost has considerable impact on carbon exchange between the atmosphere and the ground and on the hydrological cycle in cold regions/cold seasons.
FeCycle: Attempting an iron biogeochemical budget from a mesoscale SF6 tracer experiment in unperturbed low iron waters
Authors: Boyd P. W. , Law C. S. , Hutchins D. A. , Abraham E. R. , Croot P. L. , Ellwood M. , Frew R. D. , Hadfield M. , Hall J. , Handy S. , Hare C. , Higgins J. , Hill P. , Hunter K. A. , LeBlanc K. , Maldonado M. T. , McKay R. M. , Mioni C. , Oliver M. , Pickmere S. , Pinkerton M. , Safi K. , Sander S. , Sanudo‐Wilhelmy S. A. , Smith M. , Strzepek R. , Tovar‐Sanchez A. , Wilhelm S. W.
Published: December 2005

An improved knowledge of iron biogeochemistry is needed to better understand key controls on the functioning of high‐nitrate low‐chlorophyll (HNLC) oceanic regions. Iron budgets for HNLC waters have been constructed using data from disparate sources ranging from laboratory algal cultures to ocean physics. In summer 2003 we conducted FeCycle, a 10‐day mesoscale tracer release in HNLC waters SE of New Zealand, and measured concurrently all sources (with the exception of aerosol deposition) to, sinks of iron from, and rates of iron recycling within, the surface mixed layer. A pelagic iron budget (timescale of days) indicated that oceanic supply terms (lateral advection and vertical diffusion) were relatively small compared to the main sink (downward particulate export). Remote sensing and terrestrial monitoring reveal 13 dust or wildfire events in Australia, prior to and during FeCycle, one of which may have deposited iron at the study location. However, iron deposition rates cannot be derived from such observations, illustrating the difficulties in closing iron budgets without quantification of episodic atmospheric supply. Despite the threefold uncertainties reported for rates of aerosol deposition (Duce et al., 1991), published atmospheric iron supply for the New Zealand region is ∼50‐fold (i.e., 7‐ to 150‐fold) greater than the oceanic iron supply measured in our budget, and thus was comparable (i.e., a third to threefold) to our estimates of downward export of particulate iron. During FeCycle, the fluxes due to short term (hours) biological iron uptake and regeneration were indicative of rapid recycling and were tenfold greater than for new iron (i.e. estimated atmospheric and measured oceanic supply), giving an “fe” ratio (uptake of new iron/uptake of new + regenerated iron) of 0.17 (i.e., a range of 0.06 to 0.51 due to uncertainties on aerosol iron supply), and an “Fe” ratio (biogenic Fe export/uptake of new + regenerated iron) of 0.09 (i.e., 0.03 to 0.24).
Impacts of biomass burning emissions and land use change on Amazonian atmospheric phosphorus cycling and deposition
Authors: Mahowald Natalie M. , Artaxo Paulo , Baker Alex R. , Jickells Timothy D. , Okin Gregory S. , Randerson James T. , Townsend Alan R.
Published: December 2005

Phosphorus (P) availability constrains both carbon uptake and loss in some of the world's most productive ecosystems. In some of these regions, atmospheric aerosols appear to be an important, if not dominant, source of new P inputs. For example, previous work suggests that mineral aerosols from North Africa bring significant amounts of new phosphorus to the P‐impoverished soils of the Amazon Basin. Here we use recent observations and atmospheric transport modeling to show that the Amazon Basin itself appears to be losing atmospheric phosphorus to neighboring regions as a consequence of biomass burning emissions, anthropogenic sources of mineral aerosols and primary biogenic particles. Observations suggest that biomass burning emissions and human disturbance are responsible for ∼23% of the phosphorus flux in the Amazon. Although biomass burning and disturbance may bring new phosphorus into nondisturbed regions, as a whole the Amazon appears to be losing phosphorus through the atmosphere. Phosphorus lost via atmospheric transport from the Amazon is deposited in the adjacent oceans and in other regions downwind. These results suggest that land use change within the Amazon may substantially increase phosphorus availability to the remaining undisturbed forests, and that this fertilization mechanism could potentially contribute to recent changes in carbon uptake measured in undisturbed stands, as well as fertilizing downwind ocean regions.
Sources and delivery of carbon, nitrogen, and phosphorus to the coastal zone: An overview of Global Nutrient Export from Watersheds (NEWS) models and their application
Authors: Seitzinger S. P. , Harrison J. A. , Dumont Egon , Beusen Arthur H. W. , Bouwman A. F.
Published: December 2005

An overview of the first spatially explicit, multielement (N, P, and C), multiform (dissolved inorganic: DIN, DIP; dissolved organic: DOC, DON, DOP; and particulate: POC, PN, PP) predictive model system of river nutrient export from watersheds (Global Nutrient Export from Watersheds (NEWS)) is presented. NEWS models estimate export from 5761 watersheds globally as a function of land use, nutrient inputs, hydrology, and other factors; regional and global scale patterns as of 1995 are presented here. Watershed sources and their relative magnitudes differ by element and form. For example, anthropogenic sources dominate the export of DIN and DIP at the global scale, although their anthropogenic sources differ significantly (diffuse and point, respectively). Natural sources dominate DON and DOP export globally, although diffuse anthropogenic sources dominate in several regions in Asia, Europe and N. America. “Hot spots” where yield (kg km−2 yr−1) is high for several elements and forms were identified, including parts of Indonesia, Japan, southern Asia, and Central America, due to anthropogenic N and P inputs in some regions and high water runoff in others. NEWS models provide a tool to examine past, current and future river export of nutrients, and how humans might impact element ratios and forms, and thereby affect estuaries and coastal seas.
Postglacial eruptive history of the Western Volcanic Zone, Iceland
Authors: Sinton John , Grönvold Karl , Sæmundsson Kristján
Published: December 2005

New field observations, age constraints, and extensive chemical analyses define the complete postglacial eruptive history of the 170‐km‐long Western Volcanic Zone (WVZ) of Iceland, the ultraslow‐spreading western boundary of the south Iceland microplate. We have identified 44 separate eruptive units, 10 of which are small‐volume eruptions associated with the flanking Grímsnes system. Overall chemical variations are consistent with very simplified models of melting of a source approximating primitive mantle composition. The 17 eruptions in the first 3000 years of postglacial time account for about 64% of the total postglacial production and are incompatible‐element depleted compared to younger units, consistent with enhanced melting as a consequence of rebound immediately following deglaciation. Steadily declining eruption rates for the last 9000 years also correlate with changes in average incompatible element ratios that appear to reflect continued decline in melting extents to the present day. This result is not restricted to the WVZ, however, and may herald a decline in melting throughout all of western Iceland during later postglacial time. Lavas from the northern part of the WVZ are depleted in incompatible elements relative to those farther south at all times, indicating either a long‐wavelength gradient in mantle source composition or variations in the melting process along axis. We find no evidence in the postglacial volcanic record for current failure of the WVZ, despite evidence for continued propagation of the eastern margin of the microplate. The dominance of lava shields in the eruptive history of the WVZ contrasts with the higher number of fissure eruptions in other Icelandic volcanic zones. WVZ shields represent long‐duration, low‐effusion rate eruptions fed by recharge magma arising out of the mantle. Average effusion rate is the key variable distinguishing shield and fissure eruptions, both within the WVZ and between different volcanic zones. High effusion rate, large‐volume eruptions require the presence of large crustal magma reservoirs, which have been rare or absent in the WVZ throughout postglacial time.
Anisotropy of electrical conductivity in dry olivine
Authors: Du Frane Wyatt L. , Roberts Jeffery J. , Toffelmier Daniel A. , Tyburczy James A.
Published: December 2005

The electrical conductivity (σ) was measured for a single crystal of San Carlos olivine (Fo89.1) for all three principal orientations over oxygen fugacities 10−7 < < 101 Pa at 1100, 1200, and 1300°C. Fe‐doped Pt electrodes were used in conjunction with a conservative range of T, and time to reduce Fe loss resulting in data that is ∼0.15 log units higher in conductivity than previous studies. At 1200°C and = 10−1 Pa, σ[100] = 10−2.27S/m, σ[010] = 10−2.49S/m, σ[001] = 10−2.40S/m. The dependences of σ on T and have been simultaneously modeled with undifferentiated mixed conduction of small polarons and Mg vacancies to obtain steady‐state activation energies: Ea[100] = 0.32 eV, Ea[010] = 0.56 eV, Ea[001] = 0.71 eV. A single crystal of dry olivine would provide a maximum of ∼100.4 S/m azimuthal σ contrast for T < 1500°C. The anisotropic results are combined to create an isotropic model with Ea = 0.53 eV.
Why the melting layer radar reflectivity is not bright at 94 GHz
Authors: Kollias Pavlos , Albrecht Bruce
Published: December 2005

At 94 GHz, the highest radar frequency used for atmospheric research, no radar bright band is observed at the melting layer. In this study, simulations of a vertical profile of melting particles and their scattering properties for a variety of melting particle models are used to capture the basic features of the radar reflectivity structure at 94 GHz in the melting layer. Observations of stratiform precipitation from vertically pointing 3 GHz and 94 GHz radars are used for comparison with the model results. The simulations show good agreement with the observations. The melting of precipitating particles results in an abrupt increase in the radar reflectivity at 94 GHz without a subsequent decrease at the base of the melting layer. The simulations also captured a small decrease in the radar reflectivity at 94 GHz (dark band) often observed at the top of the melting layer.
Low energy electron microsignatures at the orbit of Tethys: Cassini MIMI/LEMMS observations
Authors: Roussos E. , Krupp N. , Woch J. , Lagg A. , Jones G. H. , Paranicas C. , Mitchell D. G. , Livi S. , Krimigis S. M. , Dougherty M. K. , Armstrong T. , Ip W.‐H. , Motschmann U.
Published: December 2005

We report on low energy electron microsignature observations by the Low Energy Magnetospheric Measurement System (LEMMS) in the vicinity of Tethys's L‐shell, during the first seven orbits of the Cassini mission. Tethys, due to its large size, is the source of strong microsignatures. Shallower absorption features seen are the result of aged Tethys microsignatures rather than the effect of its small Lagrangian moons. Several remarkable observations are also discussed: the displacement of the microsignatures indicates that the drift shell deviation from axisymmetry is greater than previously expected. Midnight to dawn wakes have drifted toward the planet whereas noon to dusk ones have drifted outward, revealing possible magnetospheric convection effects. Double microsignatures seen for the first time, suggest low radial diffusion coefficients and point to dynamic events in the magnetosphere.
Evaluation of AIRS cloud properties using MPACE data
Authors: Wu Xuebao , Li Jun , Menzel W. Paul , Huang Allen , Baggett Kevin , Revercomb Henry
Published: December 2005

Retrieval of cloud properties from the Atmospheric Infrared Sounder (AIRS) aboard the NASA Aqua satellite has been investigated. The cloud products from the collocated MODerate resolution Imaging Spectroradiometer (MODIS) data are used to characterize the AIRS sub‐pixel cloud information such as cloud phase, cloud coverage, and cloud layer information. A Minimum Residual (MR) approach is used to retrieve cloud microphysical properties once the cloud top pressure (CTP) and effective cloud amount (ECA) are determined from AIRS CO2 absorption channels between 720 and 790 cm−1. The cloud microphysical properties can be retrieved by minimizing the differences between the observations and the calculations using AIRS longwave window channels between 790 and 1130 cm−1. AIRS is used to derive cloud properties during the Mixed Phase Arctic Cloud Experiment (MPACE) field campaign. Comparison with measurements obtained from lidar data is made for a test day, showing that AIRS cloud property retrievals agree with in situ lidar observations. Due to the large solar zenith angle, the MODIS operational retrieval approach is not able to provide cloud microphysics north of Barrow, Alaska; however, AIRS provides cloud microphysical properties with its high spectral resolution IR measurements.
Earthquake source‐parameter estimation using regional waveforms: Implications for tsunami alerting in the Caribbean
Authors: Mendoza C.
Published: December 2005

Three‐component seismic waveforms recorded at the single broadband station SJG have been examined for four MW ≥ 6 Caribbean earthquakes using a regional moment‐tensor (RMT) inversion procedure that uses a general crustal velocity model to generate synthetic Green's functions at a fixed depth. Comparisons of the computed source parameters with solutions reported by international agencies indicate that the RMT procedure provides a rapid estimate of the earthquake magnitude using a single station. Focal mechanisms are not as well resolved and may require a more complete azimuthal coverage. The inversion procedure thus provides a timely estimate of the earthquake magnitude that would be useful for tsunami alerting. Warning intervals for the Caribbean region would vary from about 12 minutes for a tsunami generated at a distance of 200 km to more than 60 minutes for a tsunami originating at a distance of 800 km from the recording site.
Variability of Nares Strait ice flux
Authors: Kwok Ron
Published: December 2005

Six years (1996–2002) of Arctic Ocean ice flux into the Nares Strait are estimated using RADARSAT ice motion. This represents a first consistent multi‐year record of Nares Strait outflow for examination of seasonal and interannual variability. Across an ∼30 km gate at the entrance to Robeson Channel, the average annual (Sept–Aug) ice area flux is 33 × 103 km2 and ranges from 16 × 103 km2 in 2000 to 48 × 103 km2 in 1999. Uncertainties in the 3‐day ice displacements and ice flux are small. Assuming 4 m thick ice, the average volume flux amounts to ∼130 km3 (∼4 mSv); this is ∼7% of the mean annual Fram Strait ice flux. Seasonally, ice flux is most active after July, ceases after the formation of an ice arch in mid‐ to late‐winter, and re‐commences after breakup in summer. The multiyear (MY) ice coverage of the area poleward of the gate is high (>80%). South of the gate, the MY ice coverage is highly variable and the strait may be filled with multiyear or seasonal ice. Our estimates are placed in the context of others and uncertainties in the other components of Canadian Archipelago ice flux and are discussed.
Relevance of time‐varying and time‐invariant retrieval error sources on the utility of spaceborne soil moisture products
Authors: Crow Wade T. , Koster Randal D. , Reichle Rolf H. , Sharif Hatim O.
Published: December 2005

Errors in remotely‐sensed soil moisture retrievals originate from a combination of time‐invariant and time‐varying sources. For land modeling applications such as forecast initialization, some of the impact of time‐invariant sources can be removed given known differences between observed and modeled soil moisture climatologies. Nevertheless, the distinction is seldom made when evaluating remotely‐sensed soil moisture products. Here we describe an Observing System Simulation Experiment (OSSE) for radiometer‐only soil moisture products derived from the NASA Hydrosphere States (Hydros) mission where the impact of time‐invariant errors is explicitly removed via the linear rescaling of retrievals. OSSE results for the 575,000 km2 Red‐Arkansas River Basin indicate that climatological rescaling may significantly reduce the perceived magnitude of Hydros soil moisture retrieval errors and expands the geographic areas over which retrievals demonstrate value for land surface modeling applications.
Diminished contribution of ram pressure to Dst during magnetic storms
Authors: Siscoe G. L. , McPherron R. L. , Jordanova V. K.
Published: December 2005

A statistical determination of the coefficient of the ram pressure term in the Burton et al. equation for Dst has shown that it drops substantially during solar wind conditions that produce magnetic storms. This result is here confirmed and extended. In a separate study based on MHD simulations, the Chapman‐Ferraro current system, which transfers the Dst‐increasing signal of the ram pressure, has been shown to be replaced by the region 1 current system, which based on geometrical considerations we argue probably makes a smaller contribution to Dst. These two studies suggest that the ram pressure correction to Dst is probably less than that usually assumed during the main phases of magnetic storms. This suggestion is illustrated by an analysis of a storm in which Dst calculated from a kinetic ring current model fits the uncorrected Dst curve better than the pressure‐corrected curve at the peak of the main phase. The work presented here illustrates a new approach to the study of storm‐time solar wind‐magnetosphere coupling.
Seasonal and longitudinal variation of large‐scale topside equatorial plasma depletions
Authors: Hei M. A. , Heelis R. A. , McClure J. P.
Published: December 2005

We examine the large‐scale properties of three classes of equatorial topside plasma depletions referred to as channels. In order of increasing zonal width and internal large‐scale substructuring, we study simple channels, multichannels, and superchannels. We find that peaks in channel activity are centered on 0° (African sector) and 180° (Western Pacific sector). Superchannels are found to strongly dominate in the African sector, whereas simple and multichannels dominate the Pacific sector. Within the African sector, the relative proportions of the three channel classes remain stable in all seasons. In the Pacific sector, simple and multichannels are dominant in all seasons of activity, though small but significant seasonal variations in channel widths and spacings are seen. Structure at a zonal scale size of about 100 km is found to be present in all channels examined. Observational and model evidence suggests that 100‐km density structure represents channels, such that all multichannels and superchannels consist of multiple contiguous simple channels. Since seeds that initiate channel formation necessarily influence large‐scale channel features, we utilize our data to draw conclusions regarding bottomside seeding conditions in the various seasonal and longitudinal sectors. Specifically, we find that strong, long‐wavelength (∼1000 km) seeds appear much more frequently in the African sector, resulting in the prevalence of superchannels there. When long‐wavelength seeds appear in the Pacific sector, they result in periodic trains of simple and multichannels. A bottomside preseeded at a scale size near 100 km accounts for the ubiquity of 100‐km scale size in the AE‐E data.
Retrieval of biomass combustion rates and totals from fire radiative power observations: FRP derivation and calibration relationships between biomass consumption and fire radiative energy release
Authors: Wooster M. J. , Roberts G. , Perry G. L. W. , Kaufman Y. J.
Published: December 2005

Estimates of wildfire aerosol and trace gas emissions are most commonly derived from assessments of biomass combusted. The radiative component of the energy liberated by burning fuel can be measured by remote sensing, and spaceborne fire radiative energy (FRE) measures can potentially provide detailed information on the amount and rate of biomass consumption over large areas. To implement the approach, spaceborne sensors must be able to derive fire radiative power (FRP) estimates from subpixel fires using observations in just one or two spectral channels, and calibration relationships between radiated energy and fuel consumption must be developed and validated. This paper presents results from a sensitivity analysis and from experimental fires conducted to investigate these issues. Within their methodological limits, the experimental work shows that FRP assessments made via independent hyperspectral and MIR radiance approaches in fact show good agreement, and fires are calculated to radiate 14 ± 3% [mean ± 1S.D.] of their theoretically available heat yield in a form capable of direct assessment by a nadir‐viewing MIR imager. The relationship between FRE and fuel mass combusted is linear and highly significant (r2 = 0.98, n = 29, p < 0.0001), and FRP is well related to combustion rate (r2 = 0.90, n = 178, p < 0.0001), though radiation from the still‐hot fuel bed can sometimes contribute significant FRP from areas where combustion has ceased. We conclude that FRE assessment offers a powerful tool for supplementing existing burned‐area based fuel consumption measures, and thus shows significant promise for enhancing pyrogenic trace gas and aerosol emissions estimates.
Analysis of the linkages between rainfall and land surface conditions in the West African monsoon through CMAP, ERS‐WSC, and NOAA‐AVHRR data
Authors: Philippon Nathalie , Mougin Eric , Jarlan Lionel , Frison Pierre‐Louis
Published: December 2005

The European Remote Sensing Wind Scatterometer (ERS‐WSC) backscattering coefficient, NOAA Advanced Very High Resolution Radiometer (NOAA‐AVHRR) Normalized Difference Vegetation Index (NDVI), and Climate Prediction Center Merged Analysis Precipitation (CMAP) precipitation data sets are studied over the period August 1991 to December 2000 to document (1) the interannual and intra‐annual evolutions of vegetation photosynthetic activity and soil‐vegetation water content over West Africa and (2) their two‐way links with precipitation. Over the Sahel, at interannual timescales the strongest relationships between vegetation, soil moisture, and precipitation are observed from July to October and when 1‐month lag is considered between the parameters. This delay reflects the vegetation response time to the moisture pulses that follow precipitation events. The high correlation between NDVI and sigma_0 at interannual timescales confirms the importance of vegetation in the backscattering coefficient. However, sigma_0 shows stronger statistical links with precipitation, suggesting that this product contains additional useful information related in particular to upper soil moisture. Over Guinea, large differences are observed between the two remote sensing products, and their relationship with precipitation at interannual timescales is weaker. Sigma_0 is significantly linked to precipitation from July to November, whereas NDVI does not show any significant relationship with precipitation. NDVI and sigma_0 serial correlations over the Sahel and Guinea suggest that a 2‐month memory usually characterizes vegetation photosynthetic activity and soil‐vegetation water content anomalies. However, anomalies disappearance in winter then reappearance in the following spring also suggests an interseason memory held by deep soil moisture reservoirs and deep‐rooted plants. A composite analysis reveals that the wettest Sahelian rainy seasons were preceded by positive anomalies of soil‐vegetation water content over Guinea from winter to spring. Cross correlations and Granger causality analyses partly relate these winter to spring land surface anomalies to those recorded in precipitation during the previous autumn. Spring soil‐vegetation water content anomalies strengthen the meridional gradient of soil‐vegetation water content over the subcontinent. This gradient is thought to contribute to the gradient of entropy that drives the West African monsoon.
Direct modal transition from space wave to surface wave leakage on microstrip lines
Authors: Baccarelli P. , Burghignoli P. , Lovat G. , Paulotto S. , Mesa F. , Jackson D. R.
Published: December 2005

In this paper it is shown for the first time that a novel transition may occur for dominant (quasi transverse electromagnetic (quasi‐TEM)) leaky modes on microstrip line, between a leaky mode that leaks into the TM0 surface wave mode and one that leaks both into the surface wave and into space. The modal evolution of leaky modes as a function of frequency is studied by means of a full‐wave spectral domain approach, and it is shown that such transitions occur on microstrip lines that have a critical strip width, which is relatively large. When the strip width is equal to the critical value, a transition frequency will exist at which the attenuation constant of the leaky mode drops exactly to zero and the leaky mode has a real propagation wave number exactly equal to the free‐space wave number. At this frequency, the leaky mode transitions from one that leaks into only the surface wave to one that also leaks into space. In a frequency neighborhood of the transition frequency, very large spurious effects may be produced because of interference between the fundamental quasi‐TEM mode and the continuous spectrum current.
Characterization of tunneling systems in molecular versus polymer glasses by high-pressure photon echo spectroscopy
Authors: McIntire Michael J. , Chronister Eric L.
Published: December 2005

Intrinsic differences between tunneling two-level systems (TLSs) in molecular versus polymeric glasses are revealed by studying the effect of compression on TLS dynamics. Photon echo studies under variable low-temperature (1.1–2.3 K) and high-pressure (0–30 kbar) conditions have been performed to contrast the effect of compression on molecular [2-methyl-tetrahydrofuran (2MTHF)] versus polymer [Polymethylmethacrylate (PMMA)] glasses. The pressure-induced reduction in the magnitude of the optical dephasing rate of rhodamine 640 in a molecular glass (2MTHF) is found to be comparable to the volume decrease of the glass (e.g., ∼20% at 30 kbar), indicating that TLSs in 2MTHF are associated with void space or low-density regions of the glass. In contrast, the relative pressure insensitivity observed for organic polymer glasses (PMMA) supports the idea that these TLSs are associated with side chain defects. The power-law exponent for the temperature-dependent dephasing in 2MTHF also decreased significantly at high pressure, suggesting a change in the form of the TLS density of states upon compression of the molecular glass.