bluuebunny/crossref_metadata_2025 huggingface dataset:
Antioxidant Activity of Moringa oleifera Tissue Extracts
Authors: Santos Andréa F. S. , Argolo Adriana C. C. , Paiva Patrícia M. G. , Coelho Luana C. B. B.
Published: February 2012

Moringa oleifera is an important source of antioxidants, tools in nutritional biochemistry that could be beneficial for human health; the leaves and flowers are used by the population with great nutritional importance. This work investigates the antioxidant activity of M. oleifera ethanolic (E1) and saline (E2) extracts from flowers (a), inflorescence rachis (b), seeds (c), leaf tissue (d), leaf rachis (e) and fundamental tissues of stem (f). The radical scavenging capacity (RSC) of extracts was determined using dot‐blots on thin layer chromatography stained with a 0.4 mm 1,1‐diphenyl‐2‐picrylhydrazyl radical (DPPH) solution; spectrophotometric assays were recorded (515 nm). Antioxidant components were detected in all E1 and E2 from a, b and d. The best RSC was obtained with E1d; the antioxidants present in E2 reacted very slowly with DPPH. The chromatogram revealed by diphenylborinate‐2‐ethylamine methanolic solution showed that the ethanolic extract from the flowers, inflorescence rachis, fundamental tissue of stem and leaf tissue contained at least three flavonoids; the saline extract from the flowers and leaf tissue revealed at least two flavonoids. In conclusion, M. oleifera ethanolic and saline extracts contain antioxidants that support the use of the plant tissues as food sources. Copyright © 2012 John Wiley & Sons, Ltd.
Packaging Design: General Framework and Research Agenda
Authors: Azzi A. , Battini D. , Persona A. , Sgarbossa F.
Published: February 2012

Traditionally, packaging design has had a subordinate role with respect to product design and production systems design; however, its impact on supply chain costs and performances can be devastating. Only in the past few years its strategic role has been recognized both in theory and in practice. Although packaging design research attracted considerable attention in the recent past, the purpose of this article is to broaden the field even further in two main directions. First, an attempt is made to review the status of literature on packaging design: a total of 89 articles published between 1990 and 2011 are reviewed and classified by content. In this contest, related International Standards are also presented and discussed, and a conceptual framework for packaging design is presented. Second, an agenda for future research in this area is provided. Copyright © 2012 John Wiley & Sons, Ltd.
On the use of EDA background error variances in the ECMWF 4D‐Var
Authors: Bonavita Massimo , Isaksen Lars , Hólm Elías
Published: February 2012

A hybrid assimilation system which uses sample statistics from an Ensemble of Data Assimilations (EDA) to estimate background error variances has been implemented at ECMWF. We show that the new system is beneficial in terms of deterministic forecast skill, provided that random and systematic errors in the estimation of variances are properly accounted for. The mechanisms through which EDA sample variances influence the deterministic analysis are clarified. An interesting aspect is that the use of flow‐dependent variances alone is able to introduce a significant degree of flow dependency in the analysis increments. Further possible improvements and extensions to the current methodology are also discussed. Copyright © 2012 Royal Meteorological Society
A suite of metrics for quantifying historical changes to predict future change‐prone classes in object‐oriented software
Authors: Elish Mahmoud O. , Al‐Rahman Al‐Khiaty Mojeeb
Published: February 2012

Software systems are subject to series of changes during their evolution as they move from one release to the next. The change histories of software systems hold useful information that describes how artifacts evolved. Evolution‐based metrics, which are the means to quantify the change history, are potentially good indicators of the changes in a software system. The objective of this paper is to derive and validate (theoretically and empirically) a set of evolution‐based metrics as potential indicators of the change‐prone classes of an object‐oriented system when moving from one release to the next. Release‐by‐release statistical prediction models were built in different ways. The results indicate that the proposed evolution‐based metrics measure different dimensions from those of typical product metrics. Additionally, several evolution‐based metrics were found to be correlated with the change‐proneness of classes. Moreover, the results indicate that more accurate prediction of class change‐proneness is achieved when the evolution‐based metrics are combined with product metrics. Copyright © 2012 John Wiley & Sons, Ltd.
Combining metrics for software evolution assessment by means of Data Envelopment Analysis
Authors: Chatzigeorgiou Alexander , Stiakakis Emmanouil
Published: February 2012

Research and practice in software engineering have led to an extensive set of metrics for the evaluation of almost every aspect of software development. One of the major challenges for any quality model is the combination of metrics, which are complementary to each other. In this paper, we propose the use of Data Envelopment Analysis (DEA), a non‐parametric technique employed in economics, as a means of providing a unified view of selected design metrics. The proposed application of DEA aims at assessing the overall trend of quality during the evolution of software systems, by considering releases of a project as units to be ranked. An important benefit derived from the use of DEA is the ability to “normalize” the evaluation over the size characteristics of the examined systems, which is vital when comparing projects of different scale. Results are presented for successive versions of two open‐source, one industrial and one research project, whereas validation, whereas validation is performed by comparing the findings with the results obtained by Analytic Hierarchy Process, which is an acknowledged multi‐criteria decision analysis approach. According to the results, DEA enables the perception of global trends in qualitative characteristics, which would be otherwise difficult to recognize and interpret. Copyright © 2012 John Wiley & Sons, Ltd.
Endosperm development: dynamic processes and cellular innovations underlying sibling altruism
Authors: Becraft Philip W. , Gutierrez‐Marcos Jose
Published: February 2012

The endosperm is a product of fertilization that evolved to support and nourish its genetic twin sibling embryo. Cereal endosperm accumulates starch and protein stores, which later support the germinating seedling. These nutritional stores prompted the domestication of cereals and are the focus of ongoing efforts for crop improvement and biotechnological innovations. Endosperm development entails several novel modifications to basic cellular and developmental processes. Cereals display nuclear endosperm development, which begins with a period of free nuclear division to generate a coenocyte. Cytoskeletal arrays distribute nuclei around the periphery of the cytoplasm and direct the subsequent deposition of cell wall material during cellularization. Positional cues and signaling systems function dynamically in the specification of the four major cell types: transfer cells, embryo‐surrounding cells, starchy endosperm (SE), and aleurone. Genome balance, epigenetic gene regulation, and parent‐of‐origin effects are essential for directing these processes. Transfer cells transport solutes, including sugars and amino acids, from the maternal plant tissues into the developing grain where they are partitioned between embryo and SE cells. Cells of the embryo‐surrounding region appear to coordinate development of the embryo and endosperm. As the seed matures, SE cells assimilate starch and protein stores, undergo DNA endoreduplication, and finally undergo programmed cell death. In contrast, aleurone cells follow a maturation program similar to the embryo, allowing them to survive desiccation. At germination, the aleurone cells secrete amylases and proteases that hydrolyze the storage products of the SE to nourish the germinating seedling. WIREs Dev Biol 2012, 1:579–593. doi: 10.1002/wdev.31

This article is categorized under:

Signaling Pathways > Cell Fate Signaling

Plant Development > Fertilization, Embryogenesis, and Seed Development
5-Aminolevulinic acid-induced protoporphyrin IX fluorescence as immediate intraoperative indicator to improve the safety of malignant or high-grade brain tumor diagnosis in frameless stereotactic biopsies
Authors: von Campe Gord , Moschopulos Michael , Hefti Martin
Published: February 2012

Background

Frameless stereotactic biopsies are replacing frame-based stereotaxy as a diagnostic approach to brain lesions. In order to avoid a sampling bias or negative histology, multiple specimens are often taken. This in turn increases the risk of hemorrhagic complications.

Objective

We present the use of 5-aminolevulinic acid (5-ALA)-induced protoporphyrin IX fluorescence in frameless stereotaxy to improve the procedure duration and yield, and thereby reduce the risk of complications.

Methods

Patients with suspected high-grade brain tumors are given 5-ALA 4 h prior to stereotactic biopsy. The biopsy needle is guided to the target using frameless stereotaxy based either on preoperative images or combined with intraoperative MRI sequences. The specimen is illuminated with blue light to look for fluorescence. In case of a positive fluorescence within the tissue sample, no frozen sections are obtained, and no further specimens are taken.

Results

The samples of 13 patients revealed a positive fluorescence and were histologically confirmed as malignant or high-grade brain neoplasms. four cases were fluorescence-negative, requiring frozen section confirmation and/or multiple samples. In theses cases histology was either nonspecific gliotic changes or low-grade tumors. There were no complications related to the additional use of 5-ALA.

Conclusion

5-ALA fluorescence in stereotactic biopsies can increase the safety and accuracy of these procedures by reducing sampling errors and eliminating the need for multiple samples and/or frozen section verification, creating a more accurate, faster and safer procedure for cases of suspected malignant or high-grade brain tumors situated in deep or eloquent areas.
Elevational gradient in the cyclicity of a forest‐defoliating insect
Authors: Haynes Kyle J. , Liebhold Andrew M. , Johnson Derek M.
Published: February 2012

Observed changes in the cyclicity of herbivore populations along latitudinal gradients and the hypothesis that shifts in the importance of generalist versus specialist predators explain such gradients has long been a matter of intense interest. In contrast, elevational gradients in population cyclicity are largely unexplored. We quantified the cyclicity of gypsy moth populations along an elevational gradient by applying wavelet analysis to spatially referenced 31‐year records (1975–2005) of defoliation. Based on geographically weighted regression and nonlinear regression, we found either a hump‐shaped or plateauing relationship between elevation and the cyclicity of gypsy moth populations and a positive relationship between cyclicity and the density of the gypsy moth's preferred host‐tree species. The potential effects of elevational gradients in the density of generalist predators and preferred host‐tree species on the cyclicity of gypsy moth populations were evaluated with mechanistic simulation models. The models suggested that an elevational gradient in the densities of preferred host tree species could partially explain elevational patterns of gypsy moth cyclicity. Results from a model assuming a type‐III functional response of generalist predators to changes in gypsy moth density were inconsistent with the observed elevational gradient in gypsy moth cyclicity. However, a model with a more realistic type‐II functional response gave results roughly consistent with the empirical findings. In contrast to classical studies on the effects of generalist predators on prey population cycles, our model with a type‐II functional response predicts a unimodal relationship between generalist‐predator density and the cyclicity of gypsy moth populations.
Effects of Food and Drug Administration‐approved medications for Alzheimer's disease on clinical progression
Authors: Mielke Michelle M. , Leoutsakos Jeannie‐Marie , Corcoran Chris D. , Green Robert C. , Norton Maria C. , Welsh‐Bohmer Kathleen A. , Tschanz JoAnn T. , Lyketsos Constantine G.
Published: February 2012

Background

Observational studies suggest that cholinesterase inhibitors and/or memantine may delay clinical progression of Alzheimer's disease (AD) in 40% of individuals taking the medications. Given this response and existence of side effects, we sought to quantify medication use and benefits in a population‐based study of incident AD cases.

Methods

The Cache County Dementia Progression Study enrolled and followed a cohort of 327 incident AD cases for a maximum of 9 years. Drug exposure was expressed using a persistency index (PI), calculated as total years of drug use divided by total years of observation. Linear mixed‐effects models examined PI, and interactions with sex and apolipoprotein E (APOE) as predictors of clinical progression on the Mini‐Mental State Examination and Clinical Dementia Rating‐Sum of Boxes.

Results

A total of 69 participants (21.1%) reported having ever used cholinesterase inhibitors or memantine. There was a strong three‐way interaction between PI, sex, and time. Among women, a higher PI (i.e., greater duration of use) of cholinesterase inhibitors was associated with slower progression on the Mini‐Mental State Examination and Clinical Dementia Rating‐Sum of Boxes, particularly among those with an APOE ε4 allele. In contrast, higher PI was associated with faster progression in males.

Conclusion

A low percentage of individuals with AD in the community are taking cholinesterase inhibitors or memantine. This study suggests that women, particularly those with an APOE ε4 allele, may benefit the most from these medications. With the newly approved increased dose of donepezil, it will be imperative to determine whether a higher dose is needed in men or whether other factors warrant consideration.
Cochlear implant electrode array misplacement: a cautionary case report
Authors: Muzzi E , Boscolo-Rizzo P , Santarelli R , Beltrame M A
Published: February 2012

Objective:

To report a series of pitfalls and complications in a case of cochlear implantation.

Method:

Case report.

Results:

An 11-year-old boy affected by auditory neuropathy underwent cochlear implantation. Intra-operative assessment was apparently consistent with correct insertion of the electrode array into the cochlea. However, subsequent high resolution computed tomography revealed that the entire electrode array was curled up within the vestibule. Revision surgery was complicated by cerebrospinal fluid leakage. A straight probe was repeatedly inserted into the internal auditory canal, before conversion to a canal wall down procedure and appropriate positioning of the electrode array.

Conclusion:

In this case, mild anteriorisation of the facial nerve created an awkward insertion angle for the electrode array via the retro-facial route, which may have triggered the described series of adverse events.
‘Nor did I socialise with their people’: Patti Smith, rock heroics and the poetics of sociability
Authors: Kane Daniel
Published: February 2012

From her time as a young performance poet in New York in the late 1960s to her current position as punk rock'séminence grise,Patti Smith has foregrounded the image of the poet as privileged seer. This essay seeks to read Smith's romantic impulses within the context of her activity in the Poetry Project at St Mark's Church, the pre-eminent public face of the Lower East Side poetry scene of the 1960s and 1970s. Ultimately, this essay will argue how Smith's complex negotiations between her understanding of the Poet as Visionary and the adamantly playful, diffuse and collaborative aesthetic characterising downtown New York's poetic community fed into the development of Smith's performative stance as proto-punk rock icon.
Human health effects of conjugated linoleic acid from milk and supplements
Authors: McCrorie Tracy A. , Keaveney Edel M. , Wallace Julie M. W. , Binns Nino , Livingstone M. Barbara E.
Published: February 2012

The primary purpose of the present review was to determine if the scientific evidence available for potential human health benefits of conjugated linoleic acid (CLA) is sufficient to support health claims on foods based on milk naturally enriched withcis-9,trans-11-CLA (c9,t11-CLA). A search of the scientific literature was conducted and showed that almost all the promising research results that have emerged in relation to cancer, heart health, obesity, diabetes and bone health have been in animal models orin vitro. Most human intervention studies have utilised synthetic CLA supplements, usually a 50:50 blend ofc9,t11-CLA andtrans-10,cis-12-CLA (t10,c12-CLA). Of these studies, the only evidence that is broadly consistent is an effect on body fat and weight reduction. A previous review of the relevant studies found that 3.2 g CLA/d resulted in a modest body fat loss in human subjects of about 0.09 kg/week, but this effect was attributed to thet10,c12-CLA isomer. There is no evidence of a consistent benefit ofc9,t11-CLA on any health conditions; and in fact both synthetic isomers, particularlyt10,c12-CLA, have been suspected of having pro-diabetic effects in individuals who are already at risk of developing diabetes. Four published intervention studies using naturally enriched CLA products were identified; however, the results were inconclusive. This may be partly due to the differences in the concentration of CLA administered in animal and human studies. In conclusion, further substantiation of the scientific evidence relating to CLA and human health benefits are required before health claims can be confirmed.
Bioeconomic model of spatial fishery management in developing countries
Authors: Akpalu Wisdom , Vondolia Godwin K.
Published: February 2012

Fishers in developing countries do not have the resources to acquire advanced technologies to exploit offshore fish stocks. As a result, the United Nations Convention on the Law of the Sea requires countries to sign partnership agreements with distant water fishing nations to exploit offshore stocks. However, for migratory stocks, the offshore may serve as a natural marine reserve (i.e., a source) to the inshore (i.e., sink); hence these partnership agreements generate a spatial externality. In this paper, we present a bioeconomic model in which a social planner uses a landing tax (ad valorem tax) to internalize this spatial externality. We found that the tax must reflect the biological connectivity between the two patches, intrinsic growth rate, the price of fish and cost per unit effort. The results are empirically illustrated using data on Ghana.
Three-Dimensional Characterization of Pigment Dispersion in Dried Paint Films Using Focused Ion Beam–Scanning Electron Microscopy
Authors: Lin Jui-Ching , Heeschen William , Reffner John , Hook John
Published: February 2012

The combination of integrated focused ion beam–scanning electron microscope (FIB-SEM) serial sectioning and imaging techniques with image analysis provided quantitative characterization of three-dimensional (3D) pigment dispersion in dried paint films. The focused ion beam in a FIB-SEM dual beam system enables great control in slicing paints, and the sectioning process can be synchronized with SEM imaging providing high quality serial cross-section images for 3D reconstruction. Application of Euclidean distance map and ultimate eroded points image analysis methods can provide quantitative characterization of 3D particle distribution. It is concluded that 3D measurement of binder distribution in paints is effective to characterize the order of pigment dispersion in dried paint films.
Infragravity wave source regions determined from ambient noise correlation
Authors: Harmon Nicholas , Henstock Timothy , Srokosz Meric , Tilmann Frederik , Rietbrock Andreas , Barton Penny
Published: February 2012

We use a backprojection method to determine dominant directions of ocean infragravity waves from 60–200 s period from cross correlations between 5 ocean bottom differential pressure gauges located off the coast of Sumatra. We observe infragravity waves arriving from all directions, but there is a dominant source direction that represents coherent propagation along the coast from the southeast or from the south. This study demonstrates the effectiveness of our projection technique, which may be applied to past and future seismic data to improve models of ocean infragravity wave generation and tsunami propagation.
Monitoring volcanic activity using correlation patterns between infrasound and ground motion
Authors: Ichihara M. , Takeo M. , Yokoo A. , Oikawa J. , Ohminato T.
Published: February 2012

This paper presents a simple method to distinguish infrasonic signals from wind noise using a cross‐correlation function of signals from a microphone and a collocated seismometer. The method makes use of a particular feature of the cross‐correlation function of vertical ground motion generated by infrasound, and the infrasound itself. Contribution of wind noise to the correlation function is effectively suppressed by separating the microphone and the seismometer by several meters because the correlation length of wind noise is much shorter than wavelengths of infrasound. The method is applied to data from two recent eruptions of Asama and Shinmoe‐dake volcanoes, Japan, and demonstrates that the method effectively detects not only the main eruptions, but also minor activity generating weak infrasound hardly visible in the wave traces. In addition, the correlation function gives more information about volcanic activity than infrasound alone, because it reflects both features of incident infrasonic and seismic waves. Therefore, a graphical presentation of temporal variation in the cross‐correlation function enables one to see qualitative changes of eruptive activity at a glance. This method is particularly useful when available sensors are limited, and will extend the utility of a single microphone and seismometer in monitoring volcanic activity.
Detection of the Earth rotation response to a rapid fluctuation of Southern Ocean circulation in November 2009
Authors: Marcus S. L. , Dickey J. O. , Fukumori I. , de Viron O.
Published: February 2012

At seasonal and shorter periods the solid Earth and its overlying geophysical fluids form a closed dynamical system, which (except for tidal forcing) conserves its total angular momentum. While atmospheric effects dominate changes in the Earth's rate of rotation and hence length‐of‐day (LOD) on these time scales, the addition of oceanic angular momentum (OAM) estimates has been shown to improve closure of the LOD budget in a statistical sense. Here we demonstrate, for the first time, the signature of a specific, sub‐monthly ocean current fluctuation on the Earth's rotation rate, coinciding with recently‐reported anomalies which developed in southeast Pacific surface temperature and bottom pressure fields during late 2009. Our results show that concurrent variations in the Antarctic Circumpolar Current (ACC), which saw a sharp drop and recovery in zonal transport during a two‐week period in November, were strong enough to cause a detectable change in LOD following the removal of atmospheric angular momentum (AAM) computed from the Modern Era Retrospective Analysis for Research and Applications (MERRA) database. The strong OAM variations driving the LOD‐AAM changes were diagnosed from ocean state estimates of the Consortium for Estimating the Circulation and Climate of the Ocean (ECCO) and involved roughly equal contributions from the current and pressure terms, with in situ confirmation for the latter provided by tide‐corrected bottom pressure recorder data from the South Drake Passage site of the Antarctic Circumpolar Current Levels by Altimetry and Island Measurements (ACCLAIM) network.
Magnetospheric electron density long‐term (>1 day) refilling rates inferred from passive radio emissions measured by IMAGE RPI during geomagnetically quiet times
Authors: Denton R. E. , Wang Y. , Webb P. A. , Tengdin P. M. , Goldstein J. , Redfern J. A. , Reinisch B. W.
Published: February 2012

Using measurements of the electron density ne found from passive radio wave observations by the IMAGE spacecraft RPI instrument on consecutive passes through the magnetosphere, we calculate the long‐term (>1 day) refilling rate of equatorial electron density dne,eq/dt from L = 2 to 9. Our events did not exhibit saturation, probably because our data set did not include a deep solar minimum and because saturation is an unusual occurrence, especially outside of solar minimum. The median rate in cm−3/day can be modeled with log10(dne,eq/dt) = 2.22 − 0.006L − 0.0347L2, while the third quartile rate can be modeled with log10(dne,eq/dt) = 3.39 − 0.353L, and the mean rate can be modeled as log10(dne,eq/dt) = 2.74 − 0.269L. These statistical values are found from the ensemble of all observed rates at each L value, including negative rates (decreases in density due to azimuthal structure or radial motion or for other reasons), in order to characterize the typical behavior. The first quartile rates are usually negative for L < 4.7 and close to zero for larger L values. Our rates are roughly consistent with previous observations of ion refilling at geostationary orbit. Most previous studies of refilling found larger refilling rates, but many of these examined a single event which may have exhibited unusually rapid refilling. Comparing refilling rates at solar maximum to those at solar minimum, we found that the refilling rate is larger at solar maximum for small L < 4, about the same at solar maximum and solar minimum for L = 4.2 to 5.8, and is larger at solar minimum for large L > 5.8 such as at geostationary orbit (L ∼ 6.8) (at least to L of about 8). These results agree with previous results for ion refilling at geostationary orbit, may agree with previous results at lower L, and are consistent with some trends for ionospheric density.
Spatial and temporal evolution of injected CO2 at the Sleipner Field, North Sea
Authors: Boait F. C. , White N. J. , Bickle M. J. , Chadwick R. A. , Neufeld J. A. , Huppert H. E.
Published: February 2012

Time‐lapse, three‐dimensional (3D) seismic surveys have imaged an accumulation of injected CO2 adjacent to the Sleipner field in the North Sea basin. The changing pattern of reflectivity suggests that CO2 accumulates within a series of interbedded sandstones and mudstones beneath a thick caprock of mudstone. Nine reflective horizons within the reservoir have been mapped on six surveys acquired between 1999 and 2008. These horizons have roughly elliptical planforms with eccentricities ranging between two and four. In the top half of the reservoir, horizon areas grow linearly with time. In the bottom half, horizon areas initially grow linearly for about eight years and then progressively shrink. The central portions of deeper reflective horizons dim with time. Amplitude analysis of horizons above, within, and below the reservoir show that this dimming is not solely caused by acoustic attenuation. Instead, it is partly attributable to CO2 migration and/or CO2 dissemination, which reduce the impedance contrast between sandstone and mudstone layers. Growth characteristics and permeability constraints suggest that each horizon grows by lateral spreading of a gravity current. This model is corroborated by the temporal pattern of horizon velocity pushdown beneath the reservoir. Horizon shrinkage may occur if the distal edge of a CO2‐filled layer penetrates the overlying mudstone, if the buoyant plume draws CO2 upward, or if the effective permeability of deeper mudstone layers increases once interstitial brine has been expelled. Topographic control is evident at later times and produces elliptical planforms, especially toward the top of the reservoir. Our results show that quantitative mapping and analysis of time‐lapse seismic surveys yield fluid dynamical insights which are testable, shedding light on the general problem of CO2 sequestration.
Measuring currents in a coastal inlet by advection of turbulent eddies in airborne optical imagery
Authors: Dugan J. P. , Piotrowski C. C.
Published: February 2012

Water current vector fields in a coastal inlet are retrieved from temporal sequences of optical imagery collected from an aircraft, the velocity being calculated by tracking modulations in the radiance from the surface. The modulations are shown to be consistent with an advecting passive tracer in turbulent flow, leading to the physical mechanism for this signature being turbulent eddies in the flow. The intensity modulations are hypothesized to be light scattered from variations in the sediment load being transported by these turbulent eddies, although other imaging mechanisms such as surface roughness variations may be occurring as well. Supporting evidence is the prevalence of the signature in sediment‐laden, nearshore flows along an exposed coast and through a tidal inlet and eddy‐like variations in the echo intensity of acoustic Doppler current profilers (ADCPs). Also, the 3‐D frequency–wave number spectrum of mapped image sequence data exhibits a classic shape that is consistent with surface turbulence generation by boils and subsequent mixing and advection by eddies in shallow channels. The velocity vector is retrieved by the geometry obtained in the least squares fit of a 2‐D planar surface representing advective variance in the 3‐D spectrum. These retrievals agree within 15 cm/s root‐mean‐square (RMS) with concurrent ADCP measurements and within 2 cm/s RMS of measurements of the Doppler shift of surface gravity waves that also are present in the data. The method provides an important new capability for measuring currents over large areas of the littorals, specifically including locations where waves are not present and visible variations in radiance from the water often are not strong.
Where can we find a seasonal cycle of the Atlantic water temperature within the Arctic Basin?
Authors: Lique Camille , Steele Michael
Published: February 2012

Recent mooring observations in the Arctic Basin suggest the existence of a seasonality of Atlantic Water (AW) temperature. Here the DRAKKAR global ocean/sea‐ice model is used to examine the seasonal cycle amplitude of AW temperature within the Arctic Ocean and to investigate the possible mechanisms governing this seasonality. The simulation as well as available mooring data reveals that the amplitude of the AW temperature seasonal cycle is significant only in the Nansen Basin along the continental slope, where AW is primarily advected. In the model, the seasonal cycle of the AW temperature is advected from Fram Strait up to St. Anna Trough and then re‐energized by the Barents Sea Branch. This suggests that the seasonal AW temperature signal survives over a finite distance (∼1000 km). Interannual changes in the seasonal cycle amplitude can be as large as the mean seasonal cycle amplitude; thus seasonality is difficult to characterize from observations spanning only a short period. The seasonal bias of in‐situ observations taken during spring and summer does not induce a large error when considering the interannual‐to‐decadal variations of AW temperature, because the seasonal cycle accounts for a small or negligible part of AW temperature variability, even near the inflow region.
Parameterization of the inertial gravity waves and generation of the quasi‐biennial oscillation
Authors: Xue X.‐H. , Liu H.‐L. , Dou X.‐K.
Published: February 2012

In this work we extend the gravity wave parameterization scheme currently used in the Whole Atmosphere Community Climate Model (WACCM), which is based upon Lindzen's linear saturation theory, by including the Coriolis effect to better describe the inertia‐gravity waves (IGW). We perform WACCM simulations to study the generation of equatorial oscillations of the zonal mean zonal winds by including a spectrum of IGWs, and the parametric dependence of the wind oscillation on the IGWs and the effect of the new scheme. These simulations demonstrate that the parameterized IGW forcing from the standard and the new scheme are both capable of generating equatorial wind oscillations with a downward phase progression in the stratosphere using the standard spatial resolution settings in the current model. The period of the oscillation is dependent on the strength of the IGW forcing, and the magnitude of the oscillation is dependent on the width of the wave spectrum. The new parameterization affects the wave breaking level and acceleration rates mainly through changing the critical level. The quasi‐biennial oscillations (QBO) can be internally generated with the proper selection of the parameters of the scheme. The characteristics of the wind oscillations thus generated are compared with the observed QBO. These experiments demonstrate the need to parameterize IGWs for generating the QBO in General Circulation Models (GCMs).
Distribution and air–sea exchange of organochlorine pesticides in the North Pacific and the Arctic
Authors: Cai Minghong , Ma Yuxin , Xie Zhiyong , Zhong Guangcai , Möller Axel , Yang Haizhen , Sturm Renate , He Jianfeng , Ebinghaus Ralf , Meng Xiang‐Zhou
Published: February 2012

Surface seawater and boundary layer air samples were collected on the icebreaker Xuelong (Snow Dragon) during the Fourth Chinese Arctic Research Expedition (CHINARE2010) cruise in the North Pacific and Arctic Oceans during 2010. Samples were analyzed for organochlorine pesticides (OCPs), including three isomers of hexachlorocyclohexane (HCH), hexachlorobenzene (HCB), and two isomers of heptachlor epoxide. The gaseous total HCH (ΣHCHs) concentrations were approximately four times lower (average 12.0 pg m−3) than those measured during CHINARE2008 (average 51.4 pg m−3), but were comparable to those measured during CHINARE2003 (average 13.4 pg m−3) in the same study area. These changes are consistent with the evident retreat of sea ice coverage from 2003 to 2008 and increase of sea ice coverage from 2008 to 2009 and 2010. Gaseous β‐HCH concentrations in the atmosphere were typically below the method detection limit, consistent with the expectation that ocean currents provide the main transport pathway for β‐HCH into the Arctic. The concentrations of all dissolved HCH isomers in seawater increase with increasing latitude, and levels of dissolved HCB also increase (from 5.7 to 7.1 pg L−1) at high latitudes (above 73°N). These results illustrate the role of cold condensation processes in the transport of OCPs. The observed air–sea gas exchange gradients in the Arctic Ocean mainly favored net deposition of OCPs, with the exception of those for β‐HCH, which favored volatilization.
Extensive surface pedogenic alteration of the Martian Noachian crust suggested by plateau phyllosilicates around Valles Marineris
Authors: Le Deit Laetitia , Flahaut Jessica , Quantin Cathy , Hauber Ernst , Mège Daniel , Bourgeois Olivier , Gurgurewicz Joanna , Massé Marion , Jaumann R.
Published: February 2012

Thousands of phyllosilicate‐rich outcrops, mainly iron or magnesium‐rich are exposed on Noachian terrains in the Martian southern highlands. We analyzed 90 CRISM observations and more than a hundred HiRISE images located on the plateaus surrounding Valles Marineris. We mapped an extensive Al‐ and Fe/Mg‐phyllosilicate‐rich formation covering at least ∼197,000 km2, for which we introduce the name “Plateau Phyllosilicates.” Tens of meters in thickness, this light‐toned formation crops out at various elevations on top of the Noachian units Npl1 and Npl2, as flat exposures on plateaus and along scarps such as valley walls, chasma walls, pit walls and impact crater rims. The Fe/Mg‐phyllosilicate‐rich lower member of the formation is composed of Fe/Mg‐smectites (nontronite, saponite) and vermiculite. The Al‐phyllosilicate‐rich upper member of the formation contains Al‐smectites (montmorillonite, beidellite) and locally kaolinite and/or halloysite. We suggest that the Plateau Phyllosilicates were mainly formed by pedogenesis related to the weathering of the Noachian bedrock by percolation of meteoric water or melted snow under a temperate and subarid climate during the Noachian Epoch in an alkaline to neutral environment. Kaolinite and/or halloysite may have formed in areas of more intense drainage at the surface under slightly acidic environments during the Noachian and Hesperian Epochs. Fluvial activity and deuteric alteration may have locally contributed to the genesis of phyllosilicates. This study suggests that the alteration of the Noachian basement of the plateaus surrounding Valles Marineris was widespread during the Noachian Epoch, and was still active during the Hesperian Epoch even though the water availability was limited.
Evaluating interannual water storage changes at watersheds in Illinois based on long‐term soil moisture and groundwater level data
Authors: Wang Dingbao
Published: February 2012

The annual water storage changes at 12 watersheds in Illinois are estimated based on the long‐term soil moisture and groundwater level observations during 1981–2003. Storage change is usually ignored in mean annual and interannual water balance calculations. However, the interannual variability of storage change can be an important component in annual water balance during dry or wet years. Annual precipitation anomaly is partitioned into annual runoff anomaly, annual evaporation anomaly, and annual storage change. The estimated annual storage change ratios vary from −60% to 40% at the study watersheds. The interannual variability of evaporation is not strongly correlated with the interannual variability of precipitation, but is correlated with the interannual variations of effective precipitation. As a response to the interannual variability of precipitation, the interannual variation of evaporation is smaller than those of runoff and storage change. The effect of annual water storage change increases the correlation coefficients between annual evaporation ratio and climate dryness index. Therefore, interannual water storage changes need to be included in the estimation of evaporation and total water supply in the Budyko framework. Effective precipitation can be used as a substitute for precipitation when computing evaporation ratio and climate dryness index.
Two-Photon Microscopy as a Tool to Study Blood Flow and Neurovascular Coupling in the Rodent Brain
Authors: Shih Andy Y , Driscoll Jonathan D , Drew Patrick J , Nishimura Nozomi , Schaffer Chris B , Kleinfeld David
Published: February 2012

The cerebral vascular system services the constant demand for energy during neuronal activity in the brain. Attempts to delineate the logic of neurovascular coupling have been greatly aided by the advent of two-photon laser scanning microscopy to image both blood flow and the activity of individual cells below the surface of the brain. Here we provide a technical guide to imaging cerebral blood flow in rodents. We describe in detail the surgical procedures required to generate cranial windows for optical access to the cortex of both rats and mice and the use of two-photon microscopy to accurately measure blood flow in individual cortical vessels concurrent with local cellular activity. We further provide examples on how these techniques can be applied to the study of local blood flow regulation and vascular pathologies such as small-scale stroke.
Pyramidal Cells and Cytochrome P450 Epoxygenase Products in the Neurovascular Coupling Response to Basal Forebrain Cholinergic Input
Authors: Lecrux Clotilde , Kocharyan Ara , Sandoe Claire H , Tong Xin-Kang , Hamel Edith
Published: February 2012

Activation of the basal forebrain (BF), the primary source of acetylcholine (ACh) in the cortex, broadly increases cortical cerebral blood flow (CBF), a response downstream to ACh release. Although endothelial nitric oxide and cholinoceptive GABA (γ-aminobutyric acid) interneurons have been implicated, little is known about the role of pyramidal cells in this response and their possible interaction with astrocytes. Using c-Fos immunohistochemistry as a marker of neuronal activation and laser-Doppler flowmetry, we measured changes in CBF evoked by BF stimulation following pharmacological blockade of c-Fos-identified excitatory pathways, astroglial metabolism, or vasoactive mediators. Pyramidal cells including those that express cyclooxygenase-2 (COX-2) displayed c-Fos upregulation. Glutamate acting via NMDA, AMPA, and mGlu receptors was involved in the evoked CBF response, NMDA receptors having the highest contribution (∼33%). In contrast, nonselective and selective COX-2 inhibition did not affect the evoked CBF response (+0.4% to 6.9%, ns). The metabolic gliotoxins fluorocitrate and fluoroacetate, the cytochrome P450 epoxygenase inhibitor MS-PPOH and the selective epoxyeicosatrienoic acids (EETs) antagonist 14,15-epoxyeicosa-5(Z)-enoic acid (14,15-EEZE) all blocked the evoked CBF response by ∼50%. Together, the data demonstrate that the hyperemic response to BF stimulation is largely mediated by glutamate released from activated pyramidal cells and by vasoactive EETs, likely originating from activated astrocytes.
Importance of T Lymphocytes in Brain Injury, Immunodeficiency, and Recovery after Cerebral Ischemia
Authors: Brait Vanessa H , Arumugam Thiruma V , Drummond Grant R , Sobey Christopher G
Published: February 2012

Following an ischemic stroke, T lymphocytes become activated, infiltrate the brain, and appear to release cytokines and reactive oxygen species to contribute to early inflammation and brain injury. However, some subsets of T lymphocytes may be beneficial even in the early stages after a stroke, and recent evidence suggests that T lymphocytes can also contribute to the repair and regeneration of the brain at later stages. In the hours to days after stroke, T-lymphocyte numbers are then reduced in the blood and in secondary lymphoid organs as part of a ‘stroke-induced immunodeficiency syndrome,’ which is mediated by hyperactivity of the sympathetic nervous system and the hypothalamic—pituitary—adrenal axis, resulting in increased risk of infectious complications. Whether or not poststroke T-lymphocyte activation occurs via an antigen-independent process, as opposed to a classical antigen-dependent process, is still controversial. Although considerable recent progress has been made, a better understanding of the roles of the different T-lymphocyte subpopulations and their temporal profile of damage versus repair will help to clarify whether T-lymphocyte targeting may be a viable poststroke therapy for clinical use.
A Critical Appraisal of Experimental Intracerebral Hemorrhage Research
Authors: MacLellan Crystal L , Paquette Rosalie , Colbourne Frederick
Published: February 2012

The likelihood of translating therapeutic interventions for stroke rests on the quality of preclinical science. Given the limited success of putative treatments for ischemic stroke and the reasons put forth to explain it, we sought to determine whether such problems hamper progress for intracerebral hemorrhage (ICH). Approximately 10% to 20% of strokes result from an ICH, which results in considerable disability and high mortality. Several animal models reproduce ICH and its underlying pathophysiology, and these models have been widely used to evaluate treatments. As yet, however, none has successfully translated. In this review, we focus on rodent models of ICH, highlighting differences among them (e.g., pathophysiology), issues with experimental design and analysis, and choice of end points. A Pub Med search for experimental ICH (years: 2007 to 31 July 2011) found 121 papers. Of these, 84% tested neuroprotectants, 11% tested stem cell therapies, and 5% tested rehabilitation therapies. We reviewed these to examine study quality (e.g., use of blinding procedures) and choice of end points (e.g., behavioral testing). Not surprisingly, the problems that have plagued the ischemia field are also prevalent in ICH literature. Based on these data, several recommendations are put forth to facilitate progress in identifying effective treatments for ICH.
Toll‐like receptor 4 is involved in bacterial endotoxin‐induced endothelial cell injury and SOC‐mediated calcium regulation
Authors: Sun Rongju , Zhu Zhihong , Su Qin , Li Tanshi , Song Qing
Published: February 2012

Bacterial endotoxins may lead to vascular endothelial cell injury. Our study explored the role of TLR4 (Toll‐like receptor 4) and STIM1 (stromal interaction molecule 1) in bacterial endotoxin‐induced calcium overload and inflammatory reactions in HUVECs (human umbilical vein endothelial cells). It showed that under LPS (lipopolysaccharide) stimulation, LBP (LPS‐binding protein) mRNA levels peaked at 24 h, TLR4 levels at 12 h and NF‐κB (nuclear factor κB) levels at 6 h (all P<0.01). LBP levels increased gradually and peaked at 24 h of LPS treatment. TLR4 protein levels increased significantly at 1 h and peaked at 12 h. NF‐κB protein levels markedly increased at 1 h and peaked at 6 h. Knockdown of STIM1 alone, TLR4 alone or both STIM1 and TLR4 together, markedly abolished LPS‐induced increase in calcium influx into cells (P<0.05, P<0.01 and P<0.01 respectively). LBP—TLR4 and STIM—NF‐κB interactions were detected without LPS treatment, enhanced by LPS stimulation, and markedly reduced by knocking down TLR4 and STIM respectively. Both the NF‐κB inhibitor, PDTC (pyrrolidine dithiocarbamate) and TLR4 knockdown could block LPS induction of NF‐κB, STIM, TNFα (tumour necrosis factor α) and IL‐6 (interleukin 6). The data indicate LPS—LBP may activate TLR4 signalling and downstream transcription factor NF‐κB, which further can activate STIM1 and eventually lead to calcium influx and injury of HUVECs. Inhibition of TLR4 effectively reverses LPS induction of inflammatory mediator generation and extracellular calcium influx mediated by STIM1.
Low-energy, high-current, ion source with cold electron emitter
Authors: Vizir A. V. , Shandrikov M. V. , Yushkov G. Yu. , Oks E. M.
Published: February 2012

An ion source based on a two-stage discharge with electron injection from a cold emitter is presented. The first stage is the emitter itself, and the second stage provides acceleration of injected electrons for gas ionization and formation of ion flow (<20 eV, 5 A dc). The ion accelerating system is gridless; acceleration is accomplished by an electric field in the discharge plasma within an axially symmetric, diverging, magnetic field. The hollow cathode electron emitter utilizes an arc discharge with cathode spots hidden inside the cathode cavity. Selection of the appropriate emitter material provides a very low erosion rate and long lifetime.
Concept for a fourth generation electron cyclotron resonance ion source
Authors: Lyneis C. , Ferracin P. , Caspi S. , Hodgkinson A. , Sabbi G. L.
Published: February 2012

A fourth generation electron cyclotron resonance ion source with an operating frequency between 40 and 56 GHz has the potential to quadruple the heavy-ion beam currents and provide a cost effective upgrade path for heavy ion drivers in use or in the planning stage at radioactive beam facilities. Design studies show it is feasible to produce the required magnetic fields in the plasma chamber, 7 T axially and 4 T in the radial direction with a magnetic structure using commercially available Nb3Sn superconducting materials. In this paper we describe the design of such a magnet structure including a 3D analysis of the Lorentz forces generated by the magnetic fields and the necessary clamping structure to stabilize the conductor against these forces.