bluuebunny/crossref_metadata_2025 huggingface dataset:
Analysis of RFI Identification and Mitigation in CAROLS Radiometer Data Using a Hardware Spectrum Analyser
Authors: Fanise Pascal , Pardé Mickaël , Zribi Mehrez , Dechambre Monique , Caudoux Christophe
Published: March 2011

A method to identify and mitigate radio frequency interference (RFI) in microwave radiometry based on the use of a spectrum analyzer has been developed. This method has been tested with CAROLS L-band airborne radiometer data that are strongly corrupted by RFI. RFI is a major limiting factor in passive microwave remote sensing interpretation. Although the 1.400–1.427 GHz bandwidth is protected, RFI sources close to these frequencies are still capable of corrupting radiometric measurements. In order to reduce the detrimental effects of RFI on brightness temperature measurements, a new spectrum analyzer has been added to the CAROLS radiometer system. A post processing algorithm is proposed, based on selective filters within the useful bandwidth divided into sub-bands. Two discriminant analyses based on the computation of kurtosis and Euclidian distances have been compared evaluated and validated in order to accurately separate the RF interference from natural signals.
The Cytoskeleton in Papillomavirus Infection
Authors: Bienkowska-Haba Malgorzata , Sapp Martin
Published: March 2011

Cytoskeleton defines the shape and structural organization of the cell. Its elements participate in cell motility, intracellular transport and chromosome movement during mitosis. Papillomaviruses (PV) are strictly epitheliotropic and induce self-limiting benign tumors of skin and mucosa, which may progress to malignancy. Like many other viruses, PV use the host cytoskeletal components for several steps during their life cycle. Prior to internalization, PV particles are transported along filopodia to the cell body. Following internalization, retrograde transport along microtubules via the dynein motor protein complex is observed. In addition, viral minichromosomes depend on the host cell machinery for partitioning of viral genomes during mitosis, which may be affected by oncoproteins E6 and E7 of high-risk human PV types. This mini-review summarizes recent advances in our understanding of papillomavirus’ interactions with the host cell cytoskeletal elements.
Superhydrophobicity in perfection: the outstanding properties of the lotus leaf
Authors: Ensikat Hans J , Ditsche-Kuru Petra , Neinhuis Christoph , Barthlott Wilhelm
Published: March 2011

Lotus leaves have become an icon for superhydrophobicity and self-cleaning surfaces, and have led to the concept of the ‘Lotus effect’. Although many other plants have superhydrophobic surfaces with almost similar contact angles, the lotus shows better stability and perfection of its water repellency. Here, we compare the relevant properties such as the micro- and nano-structure, the chemical composition of the waxes and the mechanical properties of lotus with its competitors. It soon becomes obvious that the upper epidermis of the lotus leaf has developed some unrivaled optimizations. The extraordinary shape and the density of the papillae are the basis for the extremely reduced contact area between surface and water drops. The exceptional dense layer of very small epicuticular wax tubules is a result of their unique chemical composition. The mechanical robustness of the papillae and the wax tubules reduce damage and are the basis for the perfection and durability of the water repellency. A reason for the optimization, particularly of the upper side of the lotus leaf, can be deduced from the fact that the stomata are located in the upper epidermis. Here, the impact of rain and contamination is higher than on the lower epidermis. The lotus plant has successfully developed an excellent protection for this delicate epistomatic surface of its leaves.
Dendritic Cells and CD28 Costimulation Are Required To Sustain Virus-Specific CD8+ T Cell Responses during the Effector Phase In Vivo
Authors: Dolfi Douglas V. , Duttagupta Priyanka A. , Boesteanu Alina C. , Mueller Yvonne M. , Oliai Caspian H. , Borowski Annie B. , Katsikis Peter D.
Published: March 2011

Although much is known about the initiation of immune responses, much less is known about what controls the effector phase. CD8+ T cell responses are believed to be programmed in lymph nodes during priming without any further contribution by dendritic cells (DCs) and Ag. In this study, we report the requirement for DCs, Ag, and CD28 costimulation during the effector phase of the CD8+ T cell response. Depleting DCs or blocking CD28 after day 6 of primary influenza A virus infection decreases the virus-specific CD8+ T cell response by inducing apoptosis, and this results in decreased viral clearance. Furthermore, effector CD8+ T cells adoptively transferred during the effector phase fail to expand without DC, CD28 costimulation, and cognate Ag. The absence of costimulation also leads to reduced survival of virus-specific effector cells as they undergo apoptosis mediated by the proapoptotic molecule Bim. Finally, IL-2 treatment restored the effector response in the absence of CD28 costimulation. Thus, in contrast to naive CD8+ T cells, which undergo an initial Ag-independent proliferation, effector CD8+ T cells expanding in the lungs during the effector phase require Ag, CD28 costimulation, and DCs for survival and expansion. These requirements would greatly impair effector responses against viruses and tumors that are known to inhibit DC maturation and in chronic infections and aging where CD28−/− CD8+ T cells accumulate.
Functional Plasticity of Antigen-Specific Regulatory T Cells in Context of Tumor
Authors: Addey Caroline , White Matthew , Dou Lang , Coe David , Dyson Julian , Chai Jian-Guo
Published: March 2011

Although polyclonal regulatory T cells (Tregs) that once expressed Foxp3 (ex-Tregs) derived from Foxp3+ Tregs have been described in homeostatic and autoimmune settings, little is known regarding the influence of the tumor environment on ex-Treg development. After adoptive transfer of HY-specific green Tregs (peripheral or thymic) to Rag2−/− B6 female mice bearing syngeneic HY-expressing MB49 tumors, a significant fraction rapidly lost expression of Foxp3. On the second transfer to a Rag2−/− B6 male environment, these ex-Tregs expanded strongly, whereas Tregs that maintained expression of Foxp3 expression did not. Both FACS and quantitative real-time-PCR analysis revealed that ex-Tregs upregulated genes characteristic of a Th1 effector-memory phenotype including IFN-γ and downregulated a panel of Treg-specific genes. Peripheral HY-specific green Tregs were adoptively transferred to Rag2−/− B6 male mice, to dissect the factors regulating ex-Treg differentiation. Development of ex-Tregs was more efficient in the mesenteric lymph node (mLN) than peripheral lymph node environment, correlating with a much greater level of IL-6 mRNA in mLN. In addition, the preferential development of ex-Tregs in mLN was significantly impaired by cotransfer of HY-specific naive CD4 T cells. Collectively, our study not only demonstrates the plasticity of Ag-specific Tregs in the context of the tumor environment, but also defines key molecular and cellular events that modulate ex-Treg differentiation.
Anterior Lumbar Interbody Implants: Importance of the Interdevice Distance
Authors: Subach Brian R. , Copay Anne G. , Martin Marcus M. , Schuler Thomas C.
Published: March 2011

Object. The implantation of interbody fusion cages allows for the restoration of disc height and the enlargement of the neuroforaminal space. The purpose of this study was to compare the extent of subsidence occurring after conventional cage placement compared to a novel wider cage placement technique.Methods. This study is a retrospective evaluation of radiographs of patients who underwent stand-alone single level anterior lumbar interbody fusion with lordotic titanium cages and rhBMP-2. Fifty-three patients were evaluated: 39 patients had wide cage placement (6 mm interdevice distance) and 14 had narrow cage placement (2 mm interdevice distance). Anterior and posterior intervertebral disc space heights were measured post-operatively and at follow-up imaging.Results. The decrease in anterior intervertebral disc space height was 2.05 mm versus 3.92 mm () and 1.08 mm versus 3.06 mm in posterior disc space height for the wide cage placement and the narrow cage placement respectively. The proportion of patients with subsidence greater than 2 mm was 41.0% in the wide cage patients and 85.7% for the narrow cage patients ().Conclusions. The wider cage placement significantly reduced the amount of subsidence while allowing for a greater exposed surface area for interbody fusion.
Link between Aluminum and the Pathogenesis of Alzheimer′s Disease: The Integration of the Aluminum and Amyloid Cascade Hypotheses
Authors: Kawahara Masahiro , Kato-Negishi Midori
Published: March 2011

Whilst being environmentally abundant, aluminum is not essential for life. On the contrary, aluminum is a widely recognized neurotoxin that inhibits more than 200 biologically important functions and causes various adverse effects in plants, animals, and humans. The relationship between aluminum exposure and neurodegenerative diseases, including dialysis encephalopathy, amyotrophic lateral sclerosis and Parkinsonism dementia in the Kii Peninsula and Guam, and Alzheimer′s disease (AD) has been suggested. In particular, the link between aluminum and Alzheimer′s disease has been the subject of scientific debate for several decades. However, the complex characteristics of aluminum bioavailability make it difficult to evaluate its toxicity and therefore, the relationship remains to be established. Mounting evidence has suggested that significance of oligomerization of β‐amyloid protein and neurotoxicity in the molecular mechanism of AD pathogenesis. Aluminum may play crucial roles as a cross‐linker in β‐amyloid oligomerization. Here, we review the detailed characteristics of aluminum neurotoxicity based on our own studies and the recent literatures. Our aim is to revisit the link between aluminum and AD and to integrate aluminum and amyloid cascade hypotheses in the context of β‐amyloid oligomerization and the interactions with other metals.
Balance Performance With a Cognitive Task: A Continuation of the Dual-Task Testing Paradigm
Authors: Resch Jacob E. , May Bryson , Tomporowski Phillip D. , Ferrara Michael S.
Published: March 2011

Context:

To ensure that concussed athletes return to play safely, we need better methods of measuring concussion severity and monitoring concussion resolution.

Objective:

To develop a dual-task model that assesses postural stability and cognitive processing in concussed athletes.

Design:

Repeated measures study.

Setting:

University laboratory.

Patients or Other Participants:

Twenty healthy, college-aged students (10 men, 10 women; age  =  20 ± 1.86 years, height  =  173 ± 4.10 cm, mass  =  71.83 + 35.77 kg).

Intervention(s):

Participants were tested individually in 2 sessions separated by 2 days. In one session, a balance task and a cognitive task were performed separately. In the other session, the balance and cognitive tasks were performed concurrently. The balance task consisted of 6 conditions of the Sensory Organization Test performed on the NeuroCom Smart Balance Master. The cognitive task consisted of an auditory switch task (3 trials per condition, 60 seconds per trial).

Main Outcome Measure(s):

For the balance test, scores for each Sensory Organization Test condition; the visual, vestibular, somatosensory, and visual-conflict subscores; and the composite balance score were calculated. For the cognitive task, response time and accuracy were measured.

Results:

Balance improved during 2 dual-task conditions: fixed support and fixed visual reference (t18  =  −2.34, P < .05) and fixed support and sway visual reference (t18  =  −2.72, P  =  .014). Participants' response times were longer (F1,18  =  67.77, P < .001, η2  =  0.79) and choice errors were more numerous under dual-task conditions than under single-task conditions (F1,18  =  5.58, P  =  .03, η2  =  0.24). However, differences were observed only during category-switch trials.

Conclusions:

Balance was either maintained or improved under dual-task conditions. Thus, postural control took priority over cognitive processing when the tasks were performed concurrently. Furthermore, dual-task conditions can isolate specific mental processes that may be useful for evaluating concussed individuals.
Work–Family Conflict Among Athletic Trainers in the Secondary School Setting
Authors: Pitney William A. , Mazerolle Stephanie M. , Pagnotta Kelly D.
Published: March 2011

Context:

Work–family conflict (WFC) negatively affects a professional's ability to function at work or home.

Objective:

To examine perceptions of and contributing factors to WFC among secondary school athletic trainers.

Design:

Sequential explanatory mixed-methods study.

Setting:

Secondary school.

Patients or Other Participants:

From a random sample of 1325 individuals selected from the National Athletic Trainers' Association Member Services database, 415 individuals (203 women, 212 men; age = 36.8 ± 9.3 years) provided usable online survey data. Fourteen individuals participated in follow-up interviews.

Intervention(s):

Online WFC questionnaire followed by in-depth phone interviews.

Main Outcome Measure(s):

Descriptive statistics were obtained to examine perceived WFC. Pearson product moment correlations were calculated to examine the relationship between work hours, total athletic training staff, and number of children and WFC score. We performed analysis of variance to examine differences between the independent variables of sex and control over work schedule and the dependent variable of WFC score. The a priori α was set at P ≤ .05. Qualitative data were analyzed using inductive content analysis. Multiple-analyst triangulation and member checks established trustworthiness of the qualitative data.

Results:

Mean WFC scores were 23.97 ± 7.78 for scale 1 (family defined as having a partner or spouse with or without children) and 23.17 ± 7.69 for scale 2 (family defined as individuals, including parents, siblings, grandparents, and any other close relatives, involved in one's life), indicating moderate perceived WFC. A significant relationship was found between the average hours of work per week and WFC scores: those with less scheduling control experienced more WFC. Two dimensions emerged from the qualitative methods that relate to how WFC is mitigated in the secondary school environment: (1) organizational—having colleagues and administration that understood the role demands and allowed for modifications in schedule and personal time and (2) personal—taking time for oneself and having a family that understands the work demands of an athletic trainer resulted in reduced perceived WFC.

Conclusions:

A large number of work hours per week and lack of control over work schedules affected the perceived level of WFC.
SOLiDzipper: A High Speed Encoding Method for the Next-Generation Sequencing Data
Authors: Jeon Young Jun , Park Sang Hyun , Ahn Sung Min , Hwang Hee Joung
Published: March 2011

Background

Next-generation sequencing (NGS) methods pose computational challenges of handling large volumes of data. Although cloud computing offers a potential solution to these challenges, transferring a large data set across the internet is the biggest obstacle, which may be overcome by efficient encoding methods. When encoding is used to facilitate data transfer to the cloud, the time factor is equally as important as the encoding efficiency. Moreover, to take advantage of parallel processing in cloud computing, a parallel technique to decode and split compressed data in the cloud is essential. Hence in this review, we present SOLiDzipper, a new encoding method for NGS data.

Methods

The basic strategy of SOLiDzipper is to divide and encode. NGS data files contain both the sequence and non-sequence information whose encoding efficiencies are different. In SOLiDzipper, encoded data are stored in binary data block that does not contain the characteristic information of a specific sequence platform, which means that data can be decoded according to a desired platform even in cases of Illumina, Solexa or Roche 454 data.

Results

The main calculation time using Crossbow was 173 minutes when 40 EC2 nodes were involved. In that case, an analysis preparation time of 464 minutes is required to encode data in the latest DNA compression method like G-SQZ and transmit it on a 183 Mbit/s bandwidth. However, it takes 194 minutes to encode and transmit data with SOLiDzipper under the same bandwidth conditions. These results indicate that the entire processing time can be reduced according to the encoding methods used, under the same network bandwidth conditions. Considering the limited network bandwidth, high-speed, high-efficiency encoding methods such as SOLiDzipper can make a significant contribution to higher productivity in labs seeking to take advantage of the cloud as an alternative to local computing.

Availability

http://szipper.dinfree.com . Academic/non-profit: Binary available for direct download at no cost. For-profit: Submit request for for-profit license from the web-site.
An Extension of Craig's Family of Lattices
Authors: Flores André Luiz , Interlando J. Carmelo , da Nóbrega Neto Trajano Pires
Published: March 2011

Let p be a prime, and let ζp be a primitive p-th root of unity. The lattices in Craig's family are (p –1)-dimensional and are geometrical representations of the integral ℤ[ζp]-ideals 〈1–ζp〉i , where i is a positive integer. This lattice construction technique is a powerful one. Indeed, in dimensions p – 1 where 149 ≤ p ≤ 3001, Craig's lattices are the densest packings known. Motivated by this, we construct (p – 1)(q – 1)-dimensional lattices from the integral ℤ[ζpq]-ideals 〈1 – ζp〉i〈1 – ζq〉j, where p and q are distinct primes and i and j are positive integers. In terms of sphere-packing density, the new lattices and those in Craig's family have the same asymptotic behavior. In conclusion, Craig's family is greatly extended while preserving its sphere-packing properties.
On Characterizations of Real Hypersurfaces in a Complex Space Form with η-Parallel Shape Operator
Authors: Kon S. H. , Loo Tee-How
Published: March 2011

In this paper we study real hypersurfaces in a non-flat complex space form with η-parallel shape operator. Several partial characterizations of these real hypersurfaces are obtained.
La prensa del norte argentino en la encrucijada de la comunicación cultural. La página literaria del diario La Gaceta (1949-1951)
Authors: Risco Ana María
Published: March 2011

En el presente artículo indagamos sobre las estrategias del director de un diario para conformar un proyecto cultural de trascendencia en el periodismo del norte argentino. El caso estudiado es la sección literaria del diario La Gaceta de Tucumán, considerado central para el desarrollo de la prensa escrita de la región durante el siglo XX. Nuestra investigación se enmarca teórica y metodológicamente en la sociología de la cultura. Seguimos, por un lado, los postulados de Pierre Bourdieu sobre campo intelectual y proyecto creador para la caracterización de la página literaria de dicho diario como un proyecto de dos dimensiones, individual y colectivo al mismo tiempo. Por otro lado, coincidimos con las conceptualizaciones sobre la organización de la cultura formuladas por Raymond Williams. Asimismo, tratamos nuestro objeto de estudio como parte del periodismo cultural, focalizando algunas cuestiones teóricas y analizamos la configuración de dicha sección desde la perspectiva de su director, Daniel Alberto Dessein.
Total Laryngectomy
Authors: Mohebati Arash , Shah Jatin P
Published: March 2011

Total laryngectomy since it was first performed more than a century ago has undergone numerous modifications with increasing attention to voice restoration. Function preservation has also been achieved by voice sparing surgical procedures, and organ preservation strategies with chemoradiotherapy for laryngeal carcinoma. However, total laryngectomy remains the standard of care for very advanced laryngeal cancers with cartilage destruction, and as a salvage procedure for failures to organ preservation therapies. In this article, we review the indications, complications and outcomes of total laryngectomy in the era of chemoradiotherapy.
Three-year ground based measurements of aerosol optical depth over the Eastern Mediterranean: the urban environment of Athens
Authors: Gerasopoulos E. , Amiridis V. , Kazadzis S. , Kokkalis P. , Eleftheratos K. , Andreae M. O. , Andreae T. W. , El-Askary H. , Zerefos C. S.
Published: March 2011

Abstract. Three years (2006–2008) of ground-based observations of the Aerosol Optical Depth (AOD) in the urban environment of Athens, in the Eastern Mediterranean, are analysed in this work. Measurements were acquired with a Multi-Filter Rotating Shadowband Radiometer at five wavelengths. The daily average AOD at 500 nm is 0.23, and the mean Ångström coefficient calculated between 415 and 867 nm is 1.41. The annual variability of AOD has a spring maximum dominated by coarse dust particles from the Sahara (AOD 0.34–0.42), while the diurnal pattern is typical for urban sites, with AOD steadily increasing throughout the day. The greatest contribution to the annually averaged AOD, accounting for almost 40%, comes from regional and local sources (namely the Istanbul metropolitan area, the extended areas of biomass burning around the north coast of the Black Sea, power plants spread throughout the Balkans and the industrial area in the Po valley, with average daily AOD in the range of 0.25–0.35). An additional important contribution (23%) is dust from Africa, whereas the rest of Europe contributes another 22%. The geographical distribution of the above sources in conjunction with the prevailing synoptic situation and contribution of local sources, lead to mixed types of aerosols over Athens, with highly variable contribution of fine and coarse particles to AOD in the range 10%–90%. This is the first long-term, ground based data set available for Athens, and it has also been used for the validation of satellite derived AOD by MODIS, showing good agreement on an annual basis, but with an overestimation of satellite AODs in the warm period.
The 2009–2010 Arctic polar stratospheric cloud season: a CALIPSO perspective
Authors: Pitts M. C. , Poole L. R. , Dörnbrack A. , Thomason L. W.
Published: March 2011

Abstract. Spaceborne lidar measurements from CALIPSO (Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations) are used to provide a vortex-wide perspective of the 2009–2010 Arctic PSC (polar stratospheric cloud) season to complement more focused measurements from the European Union RECONCILE (reconciliation of essential process parameters for an enhanced predictability of Arctic stratospheric ozone loss and its climate interactions) field campaign. The 2009–2010 Arctic winter was unusually cold at stratospheric levels from mid-December 2009 until the end of January 2010, and was one of only a few winters from the past fifty-two years with synoptic-scale regions of temperatures below the frost point. More PSCs were observed by CALIPSO during the 2009–2010 Arctic winter than in the previous three Arctic seasons combined. In particular, there were significantly more observations of high number density NAT (nitric acid trihydrate) mixtures (referred to as Mix 2-enh) and ice PSCs. We found that the 2009–2010 season could roughly be divided into four periods with distinctly different PSC optical characteristics. The early season (15–30 December 2009) was characterized by patchy, tenuous PSCs, primarily low number density liquid/NAT mixtures. No ice clouds were observed by CALIPSO during this early phase, suggesting that these early season NAT clouds were formed through a non-ice nucleation mechanism. The second phase of the season (31 December 2009–14 January 2010) was characterized by frequent mountain wave ice clouds that nucleated widespread NAT particles throughout the vortex, including Mix 2-enh. The third phase of the season (15–21 January 2010) was characterized by synoptic-scale temperatures below the frost point which led to a rare outbreak of widespread ice clouds. The fourth phase of the season (22–28 January) was characterized by a major stratospheric warming that distorted the vortex, displacing the cold pool from the vortex center. This final phase was dominated by STS (supercooled ternary solution) PSCs, although NAT particles may have been present in low number densities, but were masked by the more abundant STS droplets at colder temperatures. We also found distinct variations in the relative proportion of PSCs in each composition class with altitude over the course of the 2009–2010 Arctic season. Lower number density liquid/NAT mixtures were most frequently observed in the lower altitude regions of the clouds (below ~18–20 km), which is consistent with CALIPSO observations in the Antarctic. Higher number density liquid/NAT mixtures, especially Mix 2-enh, were most frequently observed at altitudes above 18–20 km, primarily downstream of wave ice clouds. This pattern is consistent with the conceptual model whereby low number density, large NAT particles are precipitated from higher number density NAT clouds (i.e. mother clouds) that are nucleated downstream of mountain wave ice clouds.
HOCl and Cl2 observations in marine air
Authors: Lawler M. J. , Sander R. , Carpenter L. J. , Lee J. D. , von Glasow R. , Sommariva R. , Saltzman E. S.
Published: March 2011

Abstract. Cl atoms in the marine atmosphere may significantly impact the lifetimes of methane and other hydrocarbons. However, the existing estimates of Cl atom levels in marine air are based on indirect evidence. Here we present measurements of the Cl precursors HOCl and Cl2 in the marine boundary layer during June of 2009 at the Cape Verde Atmospheric Observatory in the eastern tropical Atlantic. These are the first measurements of tropospheric HOCl. HOCl and Cl2 levels were low in air with open ocean back trajectories, with maximum levels always below 60 and 10 ppt (pmol/mol), respectively. In air with trajectories originating over Europe, HOCl and Cl2 levels were higher, with HOCl maxima exceeding 100 ppt each day and Cl2 reaching up to 34 ppt. The increased Cl cycling associated with long distance pollutant transport over the oceans likely impacts a wide geographic area and represents a mechanism by which human activities have increased the reactivity of the marine atmosphere. The data indicate that Cl atoms accounted for as much as 15% of the methane destruction at this site during the study period. A photochemical model does not adequately simulate the observed abundances of HOCl and Cl2, raising the possibility of an unknown HOCl source.
Liquid-like layers on ice in the environment: bridging the quasi-liquid and brine layer paradigms
Authors: Kuo M. H. , Moussa S. G. , McNeill V. F.
Published: March 2011

Abstract. Liquid-like layers on ice significantly influence atmospheric chemistry in polar regions. In the absence of impurities a nanoscale region of surface disorder known as the "quasi-liquid layer" (QLL) may exist below the bulk melting point (down to ~−30 °C). Surface and bulk impurities are known to modulate the QLL thickness. In aqueous systems containing ionic solutes, a liquid brine layer (BL) may form upon freezing due to the exclusion of impurities from the ice crystal lattice coupled with freezing point depression in the concentrated surface layer. Brine layers are conceptually distinct from the QLL, which can exist in the absence of impurities. We have developed a unified model for liquid-like layers in environmental ice systems that is valid over a wide range of temperatures and solute concentrations, spanning the QLL and BL regimes. The model consists of two coupled modules describing the thickness of the BL and the QLL. The BL module is derived from fundamental equlibrium thermodynamics, whereas the QLL formulation is derived semi-empirically based on statistical mechanical principles and previously published QLL thickness data. The resulting unified model has been tested against experimental data from literature and applied to several environmentally important systems, such as HCl(g)-ice, HNO3(g)-ice, and frozen sea ice. This model can be used to improve the representation of air-ice chemical interactions in polar atmospheric chemistry models.
The dependence of Pi2 waveforms on periodic velocity enhancements within bursty bulk flows
Authors: Murphy K. R. , Rae I. J. , Mann I. R. , Walsh A. P. , Milling D. K. , Kale A.
Published: March 2011

Abstract. Pi2s are a category of Ultra Low Frequency (ULF) waves associated with the onset of magnetic substorms. Recent work has suggested that the deceleration of bulk plasma flows in the central plasmasheet, known as bursty bulk flows (BBFs), are able to directly-drive Pi2 oscillations. Some of these studies have further shown evidence that there is a one-to-one correlation between Pi2 magnetic waveforms observed on the ground and periodic peaks in flow velocity within the BBF, known as flow bursts. Utilising a favourable conjunction between the Geotail spacecraft and the Canadian Array for Real-time Investigations of Magnetic Activity (CARISMA) magnetometer array on 31 May 1998, we examine the causality of the link between BBF flow bursts and Pi2 waveforms. Using a series of analytical tests in both the time and frequency domains, we find that while the Pi2 and BBF waveforms are very similar, the ground response for this event occurs prior to the observed flow enhancements in the magnetotail. We conclude that during this specific case study the temporal variations of the flow bursts within the BBF are not directly-driving the observed ground-based Pi2 waveforms, despite the fact that a visual inspection of both time-series might initially suggest that there is a causal relationship. We postulate that rather than there being a direct causal relation, the similar waveforms observed in both Pi2s and BBFs may result from temporal variations in a common source for both the BBFs and the Pi2s, such as magnetic reconnection in the tail, this source modulating both the Pi2 and BBF at the same frequency.
North Atlantic abrupt climatic events of the last glacial period recorded in Ukrainian loess deposits
Authors: Rousseau D.-D. , Antoine P. , Gerasimenko N. , Sima A. , Fuchs M. , Hatté C. , Moine O. , Zoeller L.
Published: March 2011

Abstract. Loess deposits are widely distributed in the Northern Hemisphere, where they have recorded not only the glacial-interglacial cycles, but also millennial-timescale changes resembling those in marine and ice cores. Such abrupt variations are clearly marked in western European series, but have not yet been evidenced in the East of the continent. Here we present results of the high-resolution investigation of a Weichselian Upper Pleniglacial loess sequence (~38–15 ka) from Stayky, Ukraine. The stratigraphy shows an alternation of loess horizons and embryonic soils, similar to sequences from western Europe. Similarities are also found between variations of a grain-size index (ratio between coarse and fine material fractions) in Stayky and in western European profiles. Based on these similarities and in agreement with the luminescence dates, the embryonic soils are associated with the Greenland interstadials (GIS) 7 to 2, and the Vytachiv paleosol at the base of the sequence, with GIS 8. Pollen analysis indicates a wetter climate for these interstadials, allowing the development of arboreal vegetation, than for the stadials, which are marked by loess formation. The grain-size index reaches the highest values for intervals correlated with the Heinrich events 3 and 2. Thus, it appears that the North Atlantic abrupt climate changes have extended their influence and modulated the loess sedimentation at least as far as eastern Europe. This result is supported by recent climate modeling experiments and recommends the Stayky sequence as a reference for further comparisons between profiles along the Eurasian loess belt centered at 50° N.
Sediment management modelling in the Blue Nile Basin using SWAT model
Authors: Betrie G. D. , Mohamed Y. A. , van Griensven A. , Srinivasan R.
Published: March 2011

Abstract. Soil erosion/sedimentation is an immense problem that has threatened water resources development in the Nile river basin, particularly in the Eastern Nile (Ethiopia, Sudan and Egypt). An insight into soil erosion/sedimentation mechanisms and mitigation methods plays an imperative role for the sustainable water resources development in the region. This paper presents daily sediment yield simulations in the Upper Blue Nile under different Best Management Practice (BMP) scenarios. Scenarios applied in this paper are (i) maintaining existing conditions, (ii) introducing filter strips, (iii) applying stone bunds (parallel terraces), and (iv) reforestation. The Soil and Water Assessment Tool (SWAT) was used to model soil erosion, identify soil erosion prone areas and assess the impact of BMPs on sediment reduction. For the existing conditions scenario, the model results showed a satisfactory agreement between daily observed and simulated sediment concentrations as indicated by Nash-Sutcliffe efficiency greater than 0.83. The simulation results showed that applying filter strips, stone bunds and reforestation scenarios reduced the current sediment yields both at the subbasins and the basin outlets. However, a precise interpretation of the quantitative results may not be appropriate because some physical processes are not well represented in the SWAT model.
Monitoring water quality in estuarine environments: lessons from the MAGEST monitoring program in the Gironde fluvial-estuarine system
Authors: Etcheber H. , Schmidt S. , Sottolichio A. , Maneux E. , Chabaux G. , Escalier J.-M. , Wennekes H. , Derriennic H. , Schmeltz M. , Quéméner L. , Repecaud M. , Woerther P. , Castaing P.
Published: March 2011

Abstract. The Gironde Estuary, one of the largest European ones, presents temporary low dissolved oxygen content in its fluvial section close to the Bordeaux urban area. In a context of population growth and of long-term environmental changes, the development of a high-frequency monitoring programme of the fluvial-estuarine system of the Gironde, called MAGEST (MArel Gironde ESTuary), had appeared essential to address current and future water-quality issues/evaluations. The objectives of the MAGEST survey program are to establish a reference database to improve the knowledge of the Gironde Estuary functioning, encompassing the aspects of hydrology, sediment dynamics and biogeochemistry. Through examples of results from intratidal to seasonal time scales, we demonstrate how such a long-term, high-frequency monitoring of a fluvio-estuarine system is of valuable interest to extract the main trends of its functioning and of the water quality in relation to external forcings (climatology, urban wastes, land use, ...) and to predict the future evolution of an estuary with global and environmental changes.
Human Resource Development for Vision 2020 in Developing Countries: A Change from Absolute Numbers
Authors: Adepoju Feyi G. , Ayanniyi Abdulkabir A. , Pam Victoria , Akanbi Toyin B.
Published: March 2011

Purpose.

To critically review the numbers, distribution, staff mix, and productivity of eye care workers (ECW) in Kwara State, north central Nigeria.

Methods.

A cross-sectional descriptive survey of all ECW identified from all eye care facilities in July 2008 was carried out using a structured questionnaire. Output data on cataract surgery of each institution were also collected and data analyzed using SPSS 16.

Results.

A total of 157 ECW comprising 8 ophthalmologists, 4 diplomates, 16 residents training ophthalmologists, 96 mid-level ophthalmic personnel (67 ophthalmic nurses, 3 optometrists, and 26 others), and 33 administrative and supporting staff were available to a population of 2.37 million. Ophthalmologist to population ratio was 1:300,000, optometrist 1:790,000, and ophthalmic nurses 1:35,000. Eighty percent of ECW and institutions are located in the state capital. There were no orthoptists, low vision specialists, counselors, or cataract finders, while optometrists, managers, and primary ECW were inadequate. The staff mix was 1 surgeon to 12 other ECW and an average of 182 cataract surgeries per surgeon per year.

Conclusions.

Emphasis should shift to team building and ensuring available workers perform optimally rather than meeting the absolute numbers of some cadre, which does not guarantee improved output. Issues of equitable distribution, appropriate staff mix, filling identified gaps in human resources, and addressing poor service uptake should be the focus to reach the goals of Vision 2020: The Right to Sight.
Extraction of scandium(III) using ionic liquids functionalized solvent impregnated resins
Authors: Zhu Lili , Liu Yinghui , Chen Ji , Liu Wanfa
Published: March 2011

Ionic liquids (ILs) functionalized solvent impregnated resins (SIRs) were prepared using IL modified Merrified resin as the polymeric supports by impregnation of extractant for extraction of Sc(III). The ILs modified Merrifield resin were prepared via covalent anchoring of imidazolium salts onto Merrifield resin. The polymeric supports with imidazolium chloride group (RCl) and imidazolium hexafluorophosphate group (RPF6) were characterized by FTIR, TGA, and elemental analysis. It was found that RCl and RPF6 had tunable hydrophilicity and hydrophobicity, different acid stability, and swelling behaviors in solvents. The effect of Cyanex 923 extractant or [C8mim][PF6] IL impregnated on RCl and RPF6 were studied. The results showed Cyanex 923 and [C8mim][PF6] exhibited stronger affinity to RPF6 than to RCl. RPF6 with Cyanex 923 was found to be effective in Sc(III) extraction. The extraction mechanisms of SIRs containing RPF6 and Cyanex 923 with or without [C8mim][PF6] were cation exchange and neutral complexation, respectively. [C8mim][PF6] acted as an extraction media and was involved in the cation exchanged extraction reaction. Sc(III) can be selectively separated from Tm(III), Yb(III), and Lu(III) by the SIRs. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Optimizing the incorporation of silica nanoparticles in polysulfone/poly(vinyl alcohol) membranes with response surface methodology
Authors: Ng Law Yong , Leo Choe Peng , Mohammad Abdul Wahab
Published: March 2011

The addition of silica nanoparticles and poly(vinyl alcohol) (PVA) to polysulfone (PSF) membranes was used to modify the membrane morphology and enhance membrane performance. The central composite design of the response surface methodology was used to predict the maximum permeability and real salt rejection (Rreal) of the PSF membranes. The factors affecting the permeability and Rreal values of the PSF membranes were the silica (0–12 wt % PSF) and PVA (0–2 wt % PSF) contents. The optimized responses, membrane permeability, and Rreal obtained experimentally were 61.9260 L m−2 h−1 bar−1 and 97.5850%, respectively, with deviation from the predicted values of 34.72 and 15.84%, respectively. In the further characterization, the contact angle results showed that PVA was important in stabilizing the nanoparticle surfaces to prevent agglomeration in the polymeric matrix. The tensile strength test confirmed that the addition of silica nanoparticles improved the mechanical strength of the PSF membranes. However, the addition of PVA had a weakening effect on the mechanical strength of the PSF membranes. The addition of silica nanoparticles and PVA affected the typical asymmetric structures of the PSF membrane less, as shown in the scanning electron micrographs. This may have been due to the good incorporation of additives in the PSF membranes, as observed from the energy‐dispersive X‐ray and Fourier transform infrared spectroscopy results. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011 Liver Transpl, 2011. © 2011 AASLD.
Consumer information (in)sufficiency in relation to biofuels: determinants and impact
Authors: Van de Velde Liesbeth , Vandermeulen Valerie , Van Huylenbroeck Guido , Verbeke Wim
Published: March 2011

Despite the growing interest in biorenewable energy at society, policy, and industry level, many people still know very little about alternatives to fossil fuels, particularly biofuels. This perspective assesses and discusses the needs of citizens and future consumers for more information on biofuels. Using empirical data collected from a sample (n = 260) of fuel consumers in Flanders, Belgium, this perspective first demonstrates that information insufficiency (the gap between consumers' need for information and their perceived knowledge) is a good predictor of information‐seeking behavior, specifically in the case of biofuels. Secondly, it shows that women, older, and less educated people report higher levels of information insufficiency. This means that they have a higher a priori interest in receiving more information about biofuels, in comparison to men, younger, and more highly educated population groups, for whom greater efforts may be required to ensure that communications reach them effectively. Additionally, information insufficiency (and thus also biofuel information‐seeking behavior) increases in line with a stronger belief that biofuels are environmentally friendly, and with weaker beliefs that biofuels will have a positive impact on the local economy and can decrease foreign energy dependency. Furthermore, outcome relevant involvement (i.e. the perceived importance of the impact of biofuels on one's own life) increases information insufficiency, whereas impression relevant involvement (i.e. the importance of perceived approval by peers) and value relevant involvement (i.e. the role of personal values) are not significant. Based on these insights, and considering the wider societal context of biofuels and the limitations of the empirical data, conclusions are drawn with respect to who is (and who is not) open to receiving information about biofuels, as well as about the specific themes and benefits such information campaigns should highlight to stand the greatest chance of success in the marketplace. Copyright © 2011 Society of Chemical Industry and John Wiley & Sons, Ltd
The cardiac lymphatic system
Authors: Loukas Marios , Abel Nicole , Shane Tubbs R. , Grabska Joanna , Birungi Judith , Anderson Robert H.
Published: March 2011

The lymphatic system, a network of vessels carrying clear interstitial fluid called lymph, is found throughout the human body. The system maintains homeostasis, receiving proteins and excess fluid from the interstitial tissues, and returning them to the venous system. Understanding of lymphatic drainage remains important in the diagnosis, prognosis, and treatment of diseases, including the metastasis of malignant diseases. Information specific to the cardiac lymphatics is scarce. Indeed, quite often the topic is not even mentioned in many medical textbooks. The goal of our review is to compile and analyze the information currently available concerning the cardiac lymphatics, hoping further to demonstrate the clinical importance of this neglected system. Clin. Anat. 24:684–691, 2011. © 2011 Wiley‐Liss, Inc.
Mining the Cinnabaramide Biosynthetic Pathway to Generate Novel Proteasome Inhibitors
Authors: Rachid Shwan , Huo Liujie , Herrmann Jennifer , Stadler Marc , Köpcke Bärbel , Bitzer Jens , Müller Rolf
Published: March 2011

The cinnabaramides and salinosporamides are mixed PKS/NRPS natural products isolated from a terrestrial streptomycete and a marine actinomycete, respectively. They interfere with the proteasome and thus potentially inhibit the growth of cancer cells. The compounds exhibit a γ‐lactam‐β‐lactone bicyclic ring structure attached to a cyclohexenyl unit and a PKS side chain. As a first step towards improving anticancer activity and permitting genetic approaches to novel analogues, we have cloned and characterized the cinnabaramide biosynthetic genes from Streptomyces sp. JS360. In addition to the expected PKS and NRPS genes, the cluster encodes functionalities for the assembly of the hexyl side chain precursor. The corresponding enzymes exhibit relaxed substrate specificities towards a number of synthesized precursors, enabling production of novel chlorinated cinnabaramides. These were isolated and analyzed for activity, revealing that derivatives bearing a chlorine atom in the PKS side chain show higher inhibitory potentials towards the proteasome's proteolytic subunits (especially the trypsin and chymotrypsin units) and higher cytotoxicities towards human tumor cell lines than the parent cinnabaramide A. Although their activities towards the proteasome were weaker than that of salinosporamide A, the cinnabaramides were found to inhibit the growth of various fungi with greater potency.
Percutaneous re‐revalvulation of the tricuspid valve
Authors: Gewillig Marc , Dubois Christophe
Published: March 2011

We report a successful percutaneous revalvulation of a dysfunctional tricuspid bioprothesis in an 8‐year‐old child. Five years after implanting a 25‐mm Carpentier‐Edwards valve in the tricuspid position, the prosthesis showed significant dysfunction with clinical right heart failure. A 26‐mm Edwards‐Sapien XT inverted aortic valve was successfully implanted through a 19F sheath using a jugular approach. Such procedure can significantly postpone the need for surgical replacement of a biological valve. © 2011 Wiley‐Liss, Inc.
Dehydrotropylium–Co2(CO)6 Ion: Generation, Reactivity and Evaluation of Cation Stability
Authors: Amiralaei Sheida , Gauld James , Green James R.
Published: March 2011

The dehydrotropylium–Co2(CO)6 ion was generated by the action of HBF4 or BF3⋅OEt2 on the corresponding cycloheptadienynol complex, which in turn has been prepared in four steps from a known diacetoxycycloheptenyne complex. The reaction of the cycloheptadienynol complex via the dehydrotropylium–Co2(CO)6 ion with several nucleophiles results in substitution reactions with reactive nucleophiles (N>1) under normal conditions, and a radical dimerisation reaction in the presence of less reactive nucleophiles. Competitive reactions of the cycloheptadienynol complex with an acyclic trienynol complex show no preference for generation of the dehydrotropylium–Co2(CO)6 ion over an acyclic cation. DFT studies on the dehydrotropylium–Co2(CO)6 ion, specifically evaluation of its harmonic oscillator model of aromaticity (HOMA) value (+0.95), its homodesmotic‐reaction‐based stabilisation energy (≈2.8 kcal mol−1) and its NICS(1) value (−2.9), taken together with the experimental studies suggest that the dehydrotropylium–Co2(CO)6 ion is weakly aromatic.