bluuebunny/crossref_metadata_2025 huggingface dataset:
A geodynamic model of plumes from the margins of Large Low Shear Velocity Provinces
Authors: Steinberger Bernhard , Torsvik Trond H.
Published: December 2011

We present geodynamic models featuring mantle plumes that are almost exclusively created at the margins of large thermo‐chemical piles in the lowermost mantle. The models are based on subduction locations and fluxes inferred from global plate reconstructions and ocean floor paleo‐ages. Sinking subducted slabs not only push a heavy chemical layer ahead, such that dome‐shaped structures form, but also push the thermal boundary layer (TBL) toward the chemical domes. At the steep edges it is forced upwards and begins to rise — in the lower part of the mantle as sheets, which then split into individual plumes higher in the mantle. The models explain why Large Igneous Provinces – commonly assumed to be caused by plumes forming in the TBL above the core‐mantle boundary (CMB)– and kimberlites during the last few hundred Myr erupted mostly above the margins of the African and Pacific Large Low Shear Velocity Provinces (LLSVPs) of the lowermost mantle, which are probably chemically distinct from and heavier than the overlying mantle. Our models support that mantle plumes are more intimately linked to plate tectonics than commonly believed. Not only can plumes cause continental break‐up, but conversely subducted plates may trigger plumes at the margins of LLSVPs near the CMB.
Hydrothermal plumes over the Carlsberg Ridge, Indian Ocean
Authors: Ray Durbar , Kamesh Raju K. A. , Baker Edward T. , Srinivas Rao A. , Mudholkar Abhay V. , Lupton John E. , Surya Prakash L. , Gawas Rekha B. , Vijaya Kumar T.
Published: December 2011

Indian Ocean ridges north of the Rodriguez Triple Junction remain poorly explored for seafloor hydrothermal activity, with only two active sites confirmed north of 25°S. We conducted water column surveys and sampling in 2007 and 2009 to search for hydrothermal plumes over a segment of the Carlsberg Ridge. Here we report evidence for two separate vent fields, one near 3°42′N, 63°40′E and another near 3°41.5′N, 63°50′E, on a segment that is apparently sparsely magmatic. Both sites appear to be located on off‐axis highs at the top of the southern axial valley wall, at depths of ∼3600 m or shallower (∼1000 m above the valley floor). At the 63°40′E site, plume sampling found local maxima in light scattering, temperature anomaly, oxidation‐reduction potential (ORP), dissolved Mn, and3He. No water samples are available from the 63°50′E site, but it showed robust light‐scattering and ORP anomalies at multiple depths, implying multiple sources. ORP anomalies are very short‐lived, so the strong signals at both sites suggest that fluid sources lie within a few kilometers or less from the plume sampling locations. Although ultramafic rocks have been recovered near these sites, the light‐scattering and dissolved Mn anomalies imply that the plumes do not arise from a system driven solely by exothermic serpentinization (e.g., Lost City). Instead, the source fluids may be a product of both ultramafic and basaltic/gabbroic fluid‐rock interaction, similar to the Rainbow and Logatchev fields on the Mid‐Atlantic Ridge.
Topography correlated atmospheric delay correction in radar interferometry using wavelet transforms
Authors: Shirzaei M. , Bürgmann R.
Published: December 2011

Atmospheric delay is one of the major sources of error in repeat pass interferometry. We propose a new approach for correcting the topography‐correlated components of this artifact. To this aim we use multiresolution wavelet analysis to identify the components of the unwrapped interferogram that correlate with topography. By using a forward wavelet transform we break down the digital elevation model and the unwrapped interferogram into their building blocks based on their frequency properties. We apply a cross‐correlation analysis to identify correlated coefficients that represent the effect of the atmospheric delay. Thus, the correction to the unwrapped interferogram is obtained by down‐weighting the correlated coefficients during inverse wavelet transform. We test this approach on real and synthetic data sets that are generated over the San Francisco Bay Area. We find that even in the presence of tectonic signals, this method is able to reduce the correlated component of the atmospheric delay by up to 75% and improves the signal in areas of high relief. The remaining part is most likely due to 3D heterogeneities of the atmosphere and can be reduced by integrating temporal information or using complementary observations or models of atmospheric delay.
Mean dynamic topography of the Arctic Ocean
Authors: Farrell Sinéad Louise , McAdoo David C. , Laxon Seymour W. , Zwally H. Jay , Yi Donghui , Ridout Andy , Giles Katharine
Published: December 2011

ICESat and Envisat altimetry data provide measurements of the instantaneous sea surface height (SSH) across the Arctic Ocean, using lead and open water elevation within the sea ice pack. First, these data were used to derive two independent mean sea surface (MSS) models by stacking and averaging along‐track SSH profiles gathered between 2003 and 2009. The ICESat and Envisat MSS data were combined to construct the high‐resolution ICEn MSS. Second, we estimate the 5.5‐year mean dynamic topography (MDT) of the Arctic Ocean by differencing the ICEn MSS with the new GOCO02S geoid model, derived from GRACE and GOCE gravity. Using these satellite‐only data we map the major features of Arctic Ocean dynamical height that are consistent with in situ observations, including the topographical highs and lows of the Beaufort and Greenland Gyres, respectively. Smaller‐scale MDT structures remain largely unresolved due to uncertainties in the geoid at short wavelengths.
Underwater glider observations and modeling of an abrupt mixing event in the upper ocean
Authors: Ruiz Simón , Renault Lionel , Garau Bartolomé , Tintoré Joaquín
Published: December 2011

An abrupt mixing event in the upper ocean is investigated in the Northwestern Mediterranean Sea using gliders, a new ocean monitoring technology, combined with regional atmospheric model outputs and mooring data. Intense winds (up to 20 m s−1) and buoyancy forcing during December 2009 induced strong vertical mixing of the upper ocean layer in the Balearic Sea. High‐resolution data from a coastal glider reveal a surface cooling of near 2 °C and the deepening of the Mixed Layer Depth (MLD) by more than 40 meters in the center of the basin. Comparisons between glider and ship‐emulated sections of hydrographic profiles show that the glider data make visible the small‐scale spatial variability of the MLD. The heat content released to the atmosphere by the upper ocean during this mixing event exceeds 1000 W m−2. A simulation from the Weather Research and Forecasting model reports values consistent with these observations. Additionally the atmospheric numerical simulation shows the development and evolution of a cyclone located south of the Balearic Islands. This cyclone is likely to be responsible for the wind intensification and the consequent air‐sea energy exchanges that occurred in the study area during this period.
Effect of water on weakening preceding rupture of laboratory‐scale faults: Implications for long‐term weakening of crustal faults
Authors: Masuda Koji , Arai Takashi , Fujimoto Koichiro , Takahashi Miki , Shigematsu Norio
Published: December 2011

The strengths of crustal faults inferred from borehole‐derived heat‐flow measurements and maximum stress orientations are lower than those determined from laboratory measurements. Because long‐term changes of fault strength cannot be directly monitored using geophysical techniques, the causes of fault weakening are not well understood. We provide laboratory evidence that supports the view that long‐term weakening of the frictional strength of faults is caused by microfracturing at asperity contacts, which is a result of crack growth at subcritical stress levels. We conducted triaxial compression tests on mylonite samples at successively higher temperatures from room temperature to 600°C to accelerate reaction processes so that they were observable at laboratory time‐scales. Our results suggest that long‐term reductions of fault strength are related to chemical reactions that take place in the presence of water. In the presence of water, frictional strength decreased as temperature increased, whereas it changed little in the absence of water. Thus, the presence of fluids has an important influence on changes of fault strength, and it is not only high fluid pressure that is important.
Passive degassing of magmatic volatiles from Iwate volcano, NE Japan, based on three‐dimensional measurement of helium isotopes in groundwater
Authors: Ohwada Michiko , Kazahaya Kohei , Itoh Jun'ich , Morikawa Noritoshi , Takahashi Masaaki , Takahashi Hiroshi A. , Inamura Akihiko , Yasuhara Masaya , Tsukamoto Hitoshi
Published: December 2011

Magmatic volatile supply to the groundwater around Iwate volcano, which is an active volcano with weak fumarolic activity, is investigated using chemical and isotopic compositions of 180 groundwater samples from various depths. Magmatic 3He flux is estimated by an applied method using helium isotopes. The three‐dimensional distribution of 3He flux can be obtained as well as that of the concentrations. High 3He flux with high concentration is found in shallow groundwaters at N and NE flanks, and in shallow and deep groundwater around the fault zone. Low 3He flux with high concentration in deep groundwater suggests the slow and long‐term accumulation of magmatic volatiles. High 3He fluxes and concentrations around the fault zone indicate that the fault acts as an ascending path of magmatic volatiles. Distribution of flux indicates the three‐dimensional anisotropy of magmatic volatile supply, which is due to the groundwater flow variation restricted by the structure of the volcanic body. Supply rates of other magmatic volatiles can be also obtained using 3He flux, and the total supply rates are estimated to be 2.3 × 10−3 (3He), 5.1 × 108 (magmatic C), 1.3 × 108 (Cl), and 1.3 × 108 (S) mol/y. Comparison of supply rate to groundwater with volcanic gas emission rate reveals that the magmatic volatiles are largely supplied to the groundwater. However, the total emission combining the groundwater and volcanic gas is not prominently large compared with other active volcanoes. We infer that the method combining the magmatic volatile concentration and flux to groundwater is available for the evaluation of passive activity of volcano.
Identifying fault heterogeneity through mapping spatial anomalies in acoustic emission statistics
Authors: Goebel T. H. W. , Becker T. W. , Schorlemmer D. , Stanchits S. , Sammis C. , Rybacki E. , Dresen G.
Published: December 2011

Seismicity clusters within fault zones can be connected to the structure, geometric complexity and size of asperities which perturb and intensify the stress field in their periphery. To gain further insight into fault mechanical processes, we study stick‐slip sequences in an analog, laboratory setting. Analysis of small scale fracture processes expressed by acoustic emissions (AEs) provide the possibility to investigate how microseismicity is linked to fault heterogeneities and the occurrence of dynamic slip events. The present work connects X‐ray computer tomography (CT) scans of faulted rock samples with spatial maps of b values (slope of the frequency‐magnitude distribution), seismic moments and event densities. Our current experimental setup facilitates the creation of a series of stick‐slips on one fault plane thus allowing us to document how individual stick‐slips can change the characteristics of AE event populations in connection to the evolution of the fault structure. We found that geometric asperities identified in CT scan images were connected to regions of low b values, increased event densities and moment release over multiple stick‐slip cycles. Our experiments underline several parallels between laboratory findings and studies of crustal seismicity, for example, that asperity regions in lab and field are connected to spatial b value anomalies. These regions appear to play an important role in controlling the nucleation spots of dynamic slip events and crustal earthquakes.
Mesoscale biogeochemical responses to iron fertilization in the upper layers of the Southern Ocean Iron Experiment areas
Authors: Hales Burke , Takahashi Taro
Published: December 2011

During the Southern Ocean Iron Experiment (SOFeX), January–February 2002, two iron fertilization experiments were conducted at the south (66.45°S, 171.8°W) and north (56.23°S, 172°W) patches. The south patch was replete with all macronutrients, whereas the north patch was nearly depleted of silicate. Using a towed water sampling/measurement system, high resolution three‐dimensional observations of temperature, salinity, CO2 partial pressure (pCO2) and the concentrations of total CO2 (TCO2), nitrate, phosphate and silicate in the upper 100 m were obtained 10 and 28 days after initial iron additions in the south and north patches, respectively. TCO2 and nutrient drawdowns observed in the south patch were small due to wind events that limited biological response in the early postfertilization period. At the north patch, drawdown signals were stronger, resulting from the longer time since fertilization. The north patch was dispersed along a frontal zone between two distinct waters, with the denser subducted under the lighter. Subduction limited CO2 uptake from the air, but provided alternative mechanisms for vertical carbon export. Based on the biogeochemical drawdowns and published estimates of the rate of the entrainment of nonfertilized waters into the patch, the mean net community productivity over 28 days was estimated to be 94 ± 12 mmol carbon m−2 day−1, to which the air‐to‐sea flux contributed only 2%. Despite low silicate concentrations and potential limitation of growth of silicifying plankton in the north patch, our estimates of the enhanced carbon uptake are similar to estimates from higher silicate environments.
Forecasting the number of extreme daily events on seasonal timescales
Authors: Hamilton Emily , Eade Rosie , Graham Richard J. , Scaife Adam A. , Smith Doug M. , Maidens Anna , MacLachlan Craig
Published: December 2011

We investigate the potential for skillfully predicting the number of daily temperature extremes over 3 month (seasonal) periods. We use retrospective forecasts from the Met Office seasonal forecasting system, GloSea4, nominally initialized 1 month ahead of the target season. Initially, we define daily extremes to be events outside either the upper or lower deciles of the daily temperature distribution from the relevant season. This definition provides a threshold that is sufficiently “extreme” to be of interest to many users but moderate enough to allow a sufficient sample for verification and to be of regular use to users. We show that skill reduces slightly at more extreme thresholds. Correlations of predicted and observed numbers of upper or lower decile extreme days over a season are significantly greater than zero over much of the globe and, in general, are better than a persistence forecast. Forecast skill for seasonal mean temperature is similar to, but generally greater than, the skill of predictions of the number of extreme days. Observations have a strong relationship between the seasonal mean and the number of extreme days. We show that the skill in predicting the number of extreme days is largely a consequence of this relationship and occurs primarily through a shift in the distribution of the daily data rather than a change of its shape. The ability to predict the El Niño–Southern Oscillation and climate change are both significant contributors to the skill in predicting temperature extremes. In summer, significant skill also comes from initializing soil moisture.
Variations in diurnal temperature range over India: Under global warming scenario
Authors: Rai Archana , Joshi Manish K. , Pandey A. C.
Published: December 2011

Annual, seasonal, and monthly trends in surface air temperature were examined over India during the period 1901–2003. Besides this, annual and seasonal trends were also scrutinized in view of global warming concerns during the 2 non‐global (1901–1909 and 1946–1975) and global (1910–1945 and 1976–2003) warming periods as defined by Intergovernmental Panel on Climate Change. A significant increasing trend of 0.743, 0.224, 0.484, and 0.52°C (100 yr)−1 has been observed in maximum (Tmax), minimum (Tmin), mean (Tmean) temperatures, and diurnal temperature range (DTR; Tmax − Tmin), respectively during the period 1901–2003. The annual temperatures (Tmean, Tmin, and Tmax) show a cooling (warming) tendency during the non‐global (global) warming periods, apart from the second non‐global warming period ofTmax. The seasonal trends in Tmin and Tmean also show similar behavior; whereas, Tmaxshows warming in all sub‐periods, excluding the first non‐global warming period of the pre‐monsoon and monsoon. Seasonal analysis depicts that, both post‐monsoon and winter seasons are getting warmer with regard toTmax and Tmin. During the analysis as well as in non‐global and global warming periods, annualDTR has increased. DTRincreases in all seasons, with the largest increase in winter and the smallest in post‐monsoon; whereas monthly analysis reveals that all the months, except March, October, and November are contributing significantly to the annual increase ofDTR. The partial correlation analysis reveals that the total cloud cover along with the secondary factors like precipitation and soil‐moisture are responsible for increase inDTR over India during the period 1948–2003.
“Chaotic” dart leaders in triggered lightning: Electric fields, X‐rays, and source locations
Authors: Hill Jonathan D. , Uman Martin A. , Jordan Douglas M. , Dwyer Joseph R. , Rassoul Hamid
Published: December 2011

We present the first published observations of “chaotic” dart leaders in triggered‐lightning discharges. We examine four leaders that exhibited “chaotic” electric field derivative (dE/dt) signatures in their final 10 to 12 μs. The dE/dt signatures were characterized by bursts exhibiting widths of the order of hundreds of nanoseconds on which were superimposed irregular pulses with widths of the order of tens of nanoseconds. These unique signatures were dissimilar from the dE/dt waveforms observed from dart or dart‐stepped leaders in triggered lightning. Three‐dimensional locations for dE/dt pulses that radiated from the bottom 200 m of the leader channels were determined, as were emission times. Vertical leader speeds for the four “chaotic” dart leaders were estimated to range from 2.0 to 4.3 × 107 m/s. A relatively continuous flux of energetic radiation (X‐rays and gamma rays) was observed during the final 10–13 μs of each “chaotic” dart leader. Some individual photons had energies more than 1 MeV. High‐speed video images of three “chaotic” dart leaders were obtained at a frame rate of 300 kilo‐frames per second (exposure time of 3.33 μs). One image, in the frame immediately prior to the return stroke, shows an upward positive leader 11.5 m in length propagating from the launch facility and a downward negative leader above with a streamer zone length of about 25 m. Channel base currents preceding the four “chaotic” dart leaders were of unusually long duration and large charge transfer, and return strokes following them had larger than usual peak currents.
Experimental evidence for the effect of hydrographs on sediment pulse dynamics in gravel‐bedded rivers
Authors: Humphries Robert , Venditti Jeremy G. , Sklar Leonard S. , Wooster John K.
Published: December 2011

Gravel augmentation is a river restoration technique applied to channels downstream of dams where size‐selective transport and lack of gravel resupply have created armored, relatively immobile channel beds. Augmentation sediment pulses rely on flow releases to move the material downstream and create conditions conducive to salmon spawning and rearing. Yet how sediment pulses respond to flow releases is often unknown. Here we explore how three types of dam releases (constant flow, small hydrograph, and large hydrograph) impact sediment transport and pulse behavior (translation and dispersion) in a channel with forced bar‐pool morphology. We use the term sediment “pulse” generically to refer to the sediment introduced to the channel, the zone of pronounced bed material transport that it causes, and the sediment wave that may form in the channel from the additional sediment supply, which can include input sediment and bed material. In our experiments, we held the volume of water released constant, which is equivalent to holding the cost of purchasing a water volume constant in a stream restoration project. The sediment pulses had the same grain size as the bed material in the channel. We found that a constant flow 60% greater than the discharge required to initiate sediment motion caused a mixture of translation and dispersion of the sediment pulse. A broad crested hydrograph with a peak flow 2.5 times the discharge required for entrainment caused pulse dispersion, while a more peaked hydrograph >3 times the entrainment threshold discharge caused pulse dispersion with some translation. The hydrographs produced a well‐defined clockwise hysteresis effecting sediment transport, as is often observed for fine‐sediment transport and transport‐limited gravel bed rivers. The results imply a rational basis for design of water releases associated with gravel augmentation that is directly linked to the desired sediment behavior.
Appropriate small dam management for minimizing catchment‐wide safety threats: International benchmarked guidelines and demonstrative cases studies
Authors: Pisaniello John D. , Tingey‐Holyoak Joanne , Burritt Roger L.
Published: December 2011

Small dam safety is generally being ignored. The potential for dam failure resulting in catastrophic consequences for downstream communities, property, and the environment, warrants exploration of the threats and policy issues associated with the management of small/farm dams. The paper achieves this through a comparative analysis of differing levels of dam safety assurance policy:absent, driven, strong, andmodel. A strategic review is undertaken to establish international dam safety policy benchmarks and to identify a best practice model. A cost‐effective engineering/accounting tool is presented to assist the policy selection process and complement the best practice model. The paper then demonstrates the significance of the small‐dam safety problem with a case study of four Australian States,policy‐absentSouth Australia,policy‐drivenVictoria,policy‐strongNew South Wales, andpolicy‐modelTasmania. Surveys of farmer behavior practices provide empirical evidence of the importance of policy and its proper implementation. Both individual and cumulative farm dam failure threats are addressed and, with supporting empirical evidence, the need for “appropriate” supervision of small dams is demonstrated. The paper adds to the existing international dam policy literature by identifying acceptable minimum level practice in private/farm dam safety assurance policy as well as updated international best practice policy guidelines while providing case study demonstration of how to apply the guidelines and empirical reinforcement of the need for “appropriate” policy. The policy guidelines, cost‐effective technology, and comparative lessons presented can assist any jurisdiction to determine and implement appropriate dam safety policy.
Experimental Subarachnoid Hemorrhage Causes Early and Long-Lasting Microarterial Constriction and Microthrombosis: An in-vivo Microscopy Study
Authors: Friedrich Benjamin , Müller Frank , Feiler Sergej , Schöller Karsten , Plesnila Nikolaus
Published: December 2011

Early brain injury (EBI) after subarachnoid hemorrhage (SAH) is characterized by a severe, cerebral perfusion pressure (CPP)-independent reduction in cerebral blood flow suggesting alterations on the level of cerebral microvessels. Therefore, we aimed to use in-vivo imaging to investigate the cerebral microcirculation after experimental SAH. Subarachnoid hemorrhage was induced in C57/BL6 mice by endovascular perforation. Pial arterioles and venules (10 to 80 μm diameter) were examined using in-vivo fluorescence microscopy, 3, 6, and 72 hours after SAH. Venular diameter or flow was not affected by SAH, while >70% of arterioles constricted by 22% to 33% up to 3 days after hemorrhage ( P<0.05 versus sham). The smaller the investigated arterioles, the more pronounced the constriction ( r2=0.92, P<0.04). Approximately 30% of constricted arterioles were occluded by microthrombi and the frequency of arteriolar microthrombosis correlated with the degree of constriction ( r2=0.93, P<0.03). The current study demonstrates that SAH induces microarterial constrictions and microthrombosis in vivo. These findings may explain the early CPP-independent decrease in cerebral blood flow after SAH and may therefore serve as novel targets for the treatment of early perfusion deficits after SAH.
Family values: Maternal care in rattlesnakes is more than mere attendance
Authors: Amarello Melissa , Smith Jeffrey , Slone John
Published: December 2011

Parental care is important in many diverse taxa because of its positive impact on the parent's fitness. Relatively simple forms of parental care, such as female attendance and defense, which is present in many squamate reptiles, will likely provide insight into the evolution of more complex forms observed in crocodilians, birds, and mammals. Historically, observations of adult and newborn rattlesnakes in close proximity were dismissed as mere coincidence of live-birth, and only recently acknowledged as examples of parental care. In 2010, we monitored 11 pregnant Arizona black rattlesnakes (Crotalus cerberus): 4 solitary individuals and 2 aggregations composed of three and four individuals. We documented various forms of parental care, including active defense of neonates against potential predators. Parental care differed among solitary and aggregated females; solitary females spent more time attending and defending their progeny than individuals in aggregations. Natural variation in group size in C. cerberus provides an ancestral condition in which to examine how group membership may increase fitness through parental care.
Inhibition of protein translocation at the endoplasmic reticulum promotes activation of the unfolded protein response
Authors: McKibbin Craig , Mares Alina , Piacenti Michela , Williams Helen , Roboti Peristera , Puumalainen Marjo , Callan Anna C. , Lesiak-Mieczkowska Karolina , Linder Stig , Harant Hanna , High Stephen , Flitsch Sabine L. , Whitehead Roger C. , Swanton Eileithyia
Published: December 2011

Selective small-molecule inhibitors represent powerful tools for the dissection of complex biological processes. ESI (eeyarestatin I) is a novel modulator of ER (endoplasmic reticulum) function. In the present study, we show that in addition to acutely inhibiting ERAD (ER-associated degradation), ESI causes production of mislocalized polypeptides that are ubiquitinated and degraded. Unexpectedly, our results suggest that these non-translocated polypeptides promote activation of the UPR (unfolded protein response), and indeed we can recapitulate UPR activation with an alternative and quite distinct inhibitor of ER translocation. These results suggest that the accumulation of non-translocated proteins in the cytosol may represent a novel mechanism that contributes to UPR activation.
Secreted CXCL12 (SDF-1) forms dimers under physiological conditions
Authors: Ray Paramita , Lewin Sarah A. , Mihalko Laura Anne , Lesher-Perez Sasha-Cai , Takayama Shuichi , Luker Kathryn E. , Luker Gary D.
Published: December 2011

Chemokine CXCL12 (CXC chemokine ligand 12) signalling through CXCR (CXC chemokine receptor) 4 and CXCR7 has essential functions in development and underlies diseases including cancer, atherosclerosis and autoimmunity. Chemokines may form homodimers that regulate receptor binding and signalling, but previous studies with synthetic CXCL12 have produced conflicting evidence for homodimerization. We used bioluminescence imaging with GL (Gaussia luciferase) fusions to investigate dimerization of CXCL12 secreted from mammalian cells. Using column chromatography and GL complementation, we established that CXCL12 was secreted from mammalian cells as both monomers and dimers. Secreted CXCL12 also formed homodimers in the extracellular space. Monomeric CXCL12 preferentially activated CXCR4 signalling through Gαi and Akt, whereas dimeric CXCL12 more effectively promoted recruitment of β-arrestin 2 to CXCR4 and chemotaxis of CXCR4-expressing breast cancer cells. We also showed that CXCR7 preferentially sequestered monomeric CXCL12 from the extracellular space and had minimal effects on dimeric CXCL12 in cell-based assays and an orthotopic tumour xenograft model of human breast cancer. These studies establish that CXCL12 secreted from mammalian cells forms homodimers under physiological conditions. Since monomeric and dimeric CXCL12 have distinct effects on cell signalling and function, our results have important implications for ongoing efforts to target CXCL12 pathways for therapy.
Differential expression of LeY and fucosyltransferase IV correlates with the receptivity of RL95‐2 and HEC‐1A human uterine epithelial cells
Authors: Liu Shuai , Yang Xuesong , Wang Jiao , Wei Jianxin , Zhang Dongmei , Wang Xiaoqi , Yan Qiu
Published: December 2011

Adhesion molecules expressed on the uterine endometrium are potential receptive markers in embryo implantation. RL95‐2 and HEC‐1A cell lines represent the high‐ and low‐receptive endometrial epithelium respectively. LeY (Lewis Y) is a difucosylated oligosaccharide highly expressed in the endometrium of some species during implantation. α1, 3 fucosylation of LeY is catalysed by FUT4 (fucosyltransferase IV), the key synthesis enzyme for LeY. We investigated whether the difference in receptivity between the 2 cell lines was related to different expressions of LeY and FUT4. RL95‐2 cells expressed a higher level of LeY and FUT4 than HEC‐1A cells, as shown by immunofluorescent staining, RT—PCR (reverse transcription—PCR) or Western blotting. FUT4‐siRNA (small interfering RNA) transfection down‐regulated FUT4 and LeY in RL95‐2 cells, and inhibited the adhesion of the embryonic cells (JAR) to RL95‐2 cell monolayer. FUT4‐cDNA, however, increased the expression of FUT4 and LeY in HEC‐1A cells, and increased the adhesion of embryonic cells to HEC‐1A cell monolayer. Alterations of LeY level by up‐ or down‐regulation of FUT4 also mediated EGFR (epidermal growth factor receptor)/MAPK (mitogen‐activated protein kinase) signalling pathway. To conclude, the expression of LeY and FUT4 correlates with endometrial receptivity, making them potential new markers for the evaluation of endometrial receptivity.
You may need the vagus nerve to understand pathophysiology and to treat diseases
Authors: De Couck Marijke , Mravec Boris , Gidron Yori
Published: December 2011

Can different pathophysiological mechanisms and risk factors leading to various diseases be linked with altered transmission of signals by one common pathway? The present article provides evidence for the hypothesis that adequate vagal nerve activity reduces the risk of major diseases, via common basic mechanisms and interim risk factors. These diseases include cardiovascular disease, cancer, Alzheimer's disease and the metabolic syndrome. Three basic mechanisms contribute to such illnesses: local oxidative stress and DNA damage, inflammatory reactions and excessive sympathetic responses, all of which are inhibited by vagal nerve activity. Efferent vagal activity that can be non-invasively measured by HRV (heart rate variability), derived from an ECG, is inversely related to all three basic mechanisms, to various risk factors (e.g. diabetes and dyslipidaemia) and, more broadly, to the diseases as well. Finally, vagal activity is proposed to moderate the effects of risk factors on developing such illnesses. By proposing an integrative neurobiological model of major diseases, identifying people at risk for, and treating patients with, such diseases may be done more efficiently. People with low HRV may be identified and subsequently treated by vagus nerve activation to possibly prevent or treat such illnesses. This proposed disease paradigm may have important preventative and therapeutic implications, whose clinical effects need to be investigated.
Bias in macrophage activation pattern influences non-alcoholic steatohepatitis (NASH) in mice
Authors: Maina Virginia , Sutti Salvatore , Locatelli Irene , Vidali Matteo , Mombello Cristina , Bozzola Cristina , Albano Emanuele
Published: December 2011

In humans, there is large inter-individual variability in the evolution of NAFLD (non-alcoholic fatty liver disease) to NASH (non-alcoholic steatohepatitis). To investigate this issue, NASH was induced with an MCD (methionine–choline-deficient) diet in C57BL/6 and Balb/c mice that are characterized by different biases in Th1/Th2 and macrophage (M1/M2) responses. Following 4 weeks on the MCD diet, steatosis and lobular inflammation were prevalent in C57BL/6 (Th1, M1 oriented) than in Balb/c (Th2, M2 oriented) mice. Consistently, hepatic TNFα (tumour necrosis factor α) mRNA expression and circulating TNFα levels were higher in MCD-fed C57BL/6 than in MCD-fed Balb/c mice. The Th1/Th2 bias did not account for the increased NASH severity, as in both strains MCD feeding did not significantly modify the liver mRNA expression of the Th1 markers IFNγ (interferon γ) and T-bet or that of the Th2 markers IL-4 (interleukin 4) and GATA-3. Conversely, MCD-fed C57BL/6 mice displayed higher liver mRNAs for the macrophage M1 activation markers iNOS (inducible NO synthase), IL-12p40 and CXCL10 (CXC chemokine ligand 10) than similarly treated Balb/c mice, without effects on the M2 polarization markers IL-10 and MGL-1 (macrophage galactose-type C-type lectin-1). Circulating IL-12 was also higher in MCD-fed C57BL/6 than in MCD-fed Balb/c mice. The analysis of macrophages isolated from the livers of MCD-fed animals confirmed an enhanced expression of M1 markers in C57BL/6 mice. Among all of the MCD-treated mice, liver iNOS, IL-12p40 and CXCL10 mRNA levels positively correlated with the frequency of hepatic necro-inflammatory foci. We concluded that the macrophage M1 bias in C57BL/6 mice may account for the increased severity of NASH in this strain, suggesting macrophage responses as important contributors to NAFLD progression.
Is Measured Hearing Aid Benefit Affected by Seeing Baseline Outcome Questionnaire Responses?
Authors: Silverman ShienPei , Cates Megan , Saunders Gabrielle
Published: December 2011

Purpose

To determine whether hearing aid outcome measured by the Hearing Handicap Inventory (HHI) for the Elderly/Adults (Newman, Weinstein, Jacobson, & Hug, 1990; Ventry & Weinstein, 1982) is differentially affected by informed vs. blind administration of the postfitting questionnaire.

Method

Participants completed the HHI at their hearing aid evaluation and again at their hearing aid follow-up visit. At follow-up, half received a clean HHI form (blind administration), whereas the remainder responded on their original form (informed administration) and could thus base their follow-up responses on those they gave at the hearing aid evaluation.

Results

The data show that for the population examined here, informed administration of the follow-up HHI did not yield a different outcome to blind administration of the follow-up HHI. This was not influenced by past hearing aid use, age of the participant, or the duration of time between baseline questionnaire completion and follow-up completion.

Conclusion

These data suggest that completion of follow-up questionnaires in either informed or blind format will have little impact on HHI responses, most likely because of the many other factors that combined to influence hearing aid outcome.
Effects of Transient Noise Reduction Algorithms on Speech Intelligibility and Ratings of Hearing Aid Users
Authors: DiGiovanni Jeffrey J. , Davlin Erin A. , Nagaraj Naveen K.
Published: December 2011

Purpose

The goal of this study was to assess the functional utility of transient noise reduction (TNR) algorithms available in hearing aids via speech intelligibility and user preferences.

Method

Two pairs of hearing aids, 1 pair each from Siemens and Unitron, were programmed for 17 hearing impaired individuals after a hearing evaluation. Intelligibility was measured for each participant for sentences presented in quiet, with 2 types of transient noise, multitalker babble, and in a combination of each type of transient noise and multitalker babble. Each condition was tested with TNR activated and TNR deactivated in a counterbalanced, single-blinded format. Subjective ratings of overall speech understanding, comfort, and sound quality were obtained for each condition.

Results

A significant improvement in speech intelligibility was measured with the TNR activated when speech was presented in multitalker babble, in the presence of chair clang transient noises, and when combining these noises. Activation of the TNR algorithm did not result in significant improvements for any of the subjective ratings.

Conclusions

While improvements were limited to certain conditions, specifically those with the chair clang transient and/or multitalker babble, TNR appears to offer an incremental step in improving the listening experience for hearing aid users.
Effect of Interdisciplinary Service Learning Experience for Audiology and Speech-Language Pathology Students Working With Adults With Dementia
Authors: Kaf Wafaa A. , Barboa Linda S. , Fisher Bradley J. , Snavely Lydia A.
Published: December 2011

Purpose

An interdisciplinary service learning (SL) experience with audiology and speech-language pathology students was designed to examine changes in students’ attitudes toward adults with dementia following an SL experience in which they socialized with nursing home residents who had dementia.

Method

Nineteen audiology and 24 speech-language pathology students completed an SL course, and 14 audiology and 18 speech-language pathology students did not participate in the SL course. The students interacted with 24 nursing home residents with dementia; specifically, the audiology students conducted 2 hearing evaluations with the residents, and the speech-language pathology students socialized with the residents during 15 visits. The students’ attitudes toward older adults with dementia were assessed using Kogan’s Attitudes Toward Old People Scale (Kogan, 1961) and qualitative analysis of their journal entries. The results were compared across groups over time.

Results

The SL groups showed more positive attitudes than the non-SL students, and their later journal entries were more positive than earlier entries.

Conclusions

This SL experience provided clinical opportunities for audiology and speech-language pathology students to work with adults with dementia. Direct contact with the residents resulted in more positive attitudes toward older adults in residential facilities.
Including Service Learning in the Undergraduate Communication Sciences and Disorders Curriculum: Benefits, Challenges, and Strategies for Success
Authors: Peters Kimberly A.
Published: December 2011

Purpose

To describe some of the benefits of service learning (SL), considerations in course development and construction, and implementation and outcomes of an SL course in the undergraduate communication sciences and disorders (CSD) program at a small, public university in northwest Washington.

Method

A review of the literature on SL and a description of the author’s experience in course development are provided on the basis of a computerized database search, library search, and discussions with the Western Washington University Center for Service Learning.

Conclusions

Teaching an SL course can present challenges to both faculty and students; nonetheless, incorporating SL into the undergraduate CSD curriculum is an excellent way of enriching the academic experience and improving critical-thinking skills of young students. SL provides hands-on opportunities for students to apply what they are learning in their CSD classes to real-world contexts, gain a better understanding of course content through engagement in real situations, and integrate information from a variety of courses in and outside of their major.
Audiologic Management of Auditory Neuropathy Spectrum Disorder in Children: A Systematic Review of the Literature
Authors: Roush Patricia , Frymark Tobi , Venediktov Rebecca , Wang Beverly
Published: December 2011

Purpose

This review summarizes current evidence related to the audiologic management of children with auditory neuropathy spectrum disorder (ANSD).

Method

A systematic search of the literature was conducted in 25 electronic databases (e.g., PubMed, CINAHL, and ERIC) using key words such asauditory neuropathy,auditory neuropathy spectrum disorder,auditory neuropathy/dyssynchrony,andhearing loss. Eighteen studies met the inclusion criteria by addressing 1 or more of 8 clinical questions. Studies were evaluated for methodological quality, and data regarding participant, intervention, and outcome variables are reported.

Results

Fifteen of the 18 studies addressed the use of cochlear implantation, and 4 addressed conventional acoustic amplification. All participants demonstrated improved auditory performance; however, all 18 studies were considered exploratory, and many had methodological limitations.

Conclusion

The clinical evidence related to intervention for ANSD is at a very preliminary stage. Additional research is needed to address the efficacy of acoustic amplification and cochlear implantation in children with ANSD and the impact of this disorder on developmental outcomes.

Supplemental Material

https://doi.org/10.23641/asha.6170171
Gabapentin for Tinnitus: A Systematic Review
Authors: Aazh Hashir , El Refaie Amr , Humphriss Rachel
Published: December 2011

Purpose

The main aim of this study was to assess the effect of gabapentin on tinnitus via a systematic review.

Method

An electronic search of literature as well as a hand search were conducted. Only double-blind randomized controlled trials (RCTs) that met all of the inclusion criteria were included in this review. The Cochrane Collaboration tool for risk of bias assessment was used to investigate the validity of the included studies. Meta-analysis was not appropriate due to inadequate details in reporting the data in the included studies. Hence, qualitative synthesis and interpretation of the data were carried out.

Results

Two studies that met the inclusion criteria were included in the review. Fourteen studies were excluded. There were substantive within-study clinical heterogeneities with regard to the baseline tinnitus handicap scores, duration of tinnitus, and severity of hearing loss in the included double-blind RCTs.

Conclusion

The authors of both studies reported that gabapentin was not superior to placebo in their primary outcomes. However, following the assessment of risk of bias and within-study clinical heterogeneities, this review concludes that there is insufficient evidence regarding the effect of gabapentin on tinnitus.
Development of the Screening Test for Hearing Problems
Authors: Demorest Marilyn E. , Wark David J. , Erdman Sue Ann
Published: December 2011

Purpose

The goal of this study was to develop a brief self-assessment instrument to screen for communication problems and psychosocial adjustment to hearing impairment as part of a rehabilitative needs assessment.

Method

A pseudorandom sample of 1,000 cases was drawn from a large, heterogeneous clinical database containing audiometric data and responses to the Communication Profile for the Hearing Impaired (CPHI; Erdman & Demorest, 1998a). Item response theory was used to derive item-characteristic curves, and item selection was based primarily on item discrimination. Internal consistency, factor structure, sensitivity, and specificity of 2 scales, Communication and Adjustment, were evaluated in a holdout sample of 319 cases from the same database.

Results

A 9-item Communication scale and an 11-item Adjustment scale both showed satisfactory internal consistency, and the 20-item test presented a clear 2-factor structure. Sensitivity and specificity functions and positive and negative predictive values indicated that the 2 scales could be used to identify the bottom 2 quartiles of the clinical population, as defined by factor scores on the CPHI.

Conclusion

The 2 scales of the Screening Test for Hearing Problems can be used to screen for communication and adjustment problems that warrant a comprehensive rehabilitative assessment.

Supplemental Material

https://doi.org/10.23641/asha.6170168
Chemical Kinetic Data Base for Combustion Chemistry. Part 3: Propane
Authors: Tsang Wing
Published: December 2011

This publication contains evaluated and estimated data on the kinetics of reactions involving propane, isopropyl radical, n-propyl radical, and various small inorganic and organic species which are of importance for proper small inorganic and organic species which are of importance for proper understanding of propane pyrolysis and combustion. It is meant to be used in conjunction with the kinetic data given in earlier publications which are of direct pertinence to the understanding of methane pyrolysis and combustion, but which also contain a large volume of data that are applicable to the propane system. The temperature range covered is 300–2500 K and the density range 1×1016 to 1×1021 molecules cm−3.
Electronic Energy Levels of Small Polyatomic Transient Molecules
Authors: Jacox M. E.
Published: December 2011

The experimentally determined eletronic energy levels of approximately 500 neutral and ionic transient molecules possessing from 3 to 6 atoms are tabulated together with the associated vibrational structure, the radiative lifetime, the principal rotational constants, and references to the pertinent literature. Vibrational and molecular beams, and in rare-gas and nitrogen matrices are included. The types of measurement surveyed include conventional and laser- based absorption and emission techniques, laser absorption with mass analysis, and ultraviolet photoelectron spectroscopy.
Measuring Urban Sprawl, Coalescence, and Dispersal: A Case Study of Pordenone, Italy
Authors: Martellozzo Federico , Clarke Keith C
Published: December 2011

A critical challenge of global change is managing the uncontrolled spread of cities into their surrounding rural and other land. The phenomenon of urban ‘sprawl’ is well known, but it remains controversial because there are no universal definitions about its etiology, nor of the causes and variables related to it. The goal of this study is to depict the temporal trend of sprawl, so as to identify a ‘sprawl signature’ and its evolution for the Italian Province of Pordenone focusing exclusively on spatial dispersion features. Data were compiled from multitemporal remote sensing and used to delimit urban expansion over time. We aim to describe the spatiotemporal patterns associated with urban sprawl using the perspective of the cyclical urban growth theory and focusing on measures that can detect the degree of spatial dispersion during time related to sprawl both in past and projected urban forms. Exactly how the spatiotemporal patterns of urban growth are identified is crucial for urban planners, as knowledge of them allows more efficient calibration of policies to control land-use change in order to satisfy specific needs of the population and prevent the risks and costs related to sprawl.