bluuebunny/crossref_metadata_2025 huggingface dataset:
Occurrence and distribution of glyphosate-resistant giant ragweed (Ambrosia trifida L.) in southwestern Ontario
Authors: Vink Joseph P. , Soltani Nader , Robinson Darren E. , Tardif François J. , Lawton Mark B. , Sikkema Peter H.
Published: April 2012

Vink, J. P., Soltani, N., Robinson, D. E., Tardif, F. J., Lawton, M. B. and Sikkema, P. H. 2012. Occurrence and distribution of glyphosate-resistant giant ragweed ( Ambrosia trifida L.) in southwestern Ontario. Can. J. Plant Sci. 92: 533–539. Giant ragweed is the first confirmed glyphosate-resistant (GR) weed in Canada. A survey was conducted to document the distribution of GR giant ragweed in southwestern Ontario. Giant ragweed seed was collected from 102 sites in Essex (70), Chatham-Kent (21), Lambton (10) and Waterloo counties (1) during the autumn of 2009 and 2010 prior to soybean harvest. Plants were grown in a growth room, sprayed with glyphosate at 1800 g a.e. ha−1 and classified as resistant or susceptible. GR giant ragweed has been confirmed at 47 new locations in three counties (Essex, Chatham-Kent and Lambton). The results from this survey indicate that GR giant ragweed biotypes occur across a greater area in southwestern Ontario than originally thought. This survey provides an important baseline for future surveys in the province.
Biologically effective rate of saflufenacil/dimethenamid-p in soybean (Glycine max)
Authors: Miller Robert T. , Soltani Nader , Robinson Darren E. , Kraus Trevor E. , Sikkema Peter H.
Published: April 2012

Miller, R. T., Soltani, N., Robinson, D. E., Kraus, T. E. and Sikkema, P. H. 2012. Biologically effective rate of saflufenacil/dimethenamid- in soybean ( Glycine max ). Can. J. Plant Sci. 92: 517–531. A total of five field studies were conducted over a 2-yr period (2009, 2010) at three Ontario locations to determine the biologically effective rate of saflufenacil/dimethenamid-p applied preemergence (PRE) for the control of annual weeds in soybean. The rate of saflufenacil/dimethenamid-p required for the control of annual weeds was influenced by environmental conditions. With adequate moisture and above-average temperatures in 2010, between 224 and 374 g a.i. ha−1 of saflufenacil/dimethenamid-p was required for 80% control of common ragweed, common lamb's quarters, and green foxtail 4 wk after treatment (WAT). In contrast, below-average temperatures and excessive moisture in 2009 resulted in higher rates of saflufenacil/dimethenamid-p being necessary for the same level of weed control. Pigweed species were least affected by environmental conditions after application at 4 WAT with only 245 g a.i. ha−1 required for 80% control in both years. By 11 WAT, 320 g a.i. ha−1 or less of saflufenacil/dimethenamid-p was required to achieve 80% control of these species in 2010, while 845 g a.i. ha−1 or more was needed in 2009 for equivalent control. The potential of saflufenacil/dimethenamid-p as a set-up treatment prior to a postemergence (POST) glyphosate application was also examined. Excellent full season control of all weed species was achieved with saflufenacil/dimethenamid-p applied PRE followed by glyphosate POST. However, there was no difference in yield when saflufenacil/dimethenamid-p was followed by glyphosate POST compared with a single glyphosate POST application.
Homotopy classes of total foliations
Authors: Asaoka Masayuki , Dufraine Emmanuel , Noda Takeo
Published: April 2012

On every compact and orientable three-manifold we construct total foliations (three codimension-one foliations that are transverse at every point). This construction can be performed on any homotopy class of plane fields with vanishing Euler class. As a corollary we obtain similar results on bi-contact structures.
Anticyclotomic Iwasawa’s Main Conjecture for Hilbert modular forms
Authors: Longo Matteo
Published: April 2012

Let

F/\mathbb{Q}

be a totally real extension and

f

an Hilbert modular cusp form of level

\mathfrak{n}

, with trivial central character and parallel weight 2, which is an eigenform for the action of the Hecke algebra. Fix a prime

\wp | \mathfrak{n}

of

F

of residual characteristic

p

. Let

K/F

be a quadratic totally imaginary extension and

K_{\wp^\infty}

be the

\wp

-anticyclotomic

\mathbb{Z}_p

-extension of

K

. The main result of this paper, generalizing the analogous result [5] of Bertolini and Darmon, states that, under suitable arithmetic assumptions and some technical restrictions, the characteristic power series of the Pontryagin dual of the Selmer group attached to

(f,K_{\wp^\infty})

divides the

p

-adic

L

-function attached to

(f,K_{\wp^\infty})

, thus proving one direction of the Anticyclotomic Main Conjecture for Hilbert modular forms. Arithmetic applications are given.
Multicurves and regular functions on the representation variety of a surface in SU(2)
Authors: Charles Laurent , Marché Julien
Published: April 2012

Given a compact surface

\Sigma

, we consider the representation space

\mathcal{M}(\Sigma)= \operatorname{Hom}(\pi_1(\Sigma),\operatorname{SU}(2))/\operatorname{SU}(2).

We show that the trace functions associated to multicurves on

\Sigma

are linearly independent as functions on

\mathcal{M}(\Sigma)

. The proof relies on the Fourier decomposition of the trace functions with respect to a torus action on

\mathcal{M}(\Sigma)

associated to a pants decomposition of

\Sigma

. Consequently the space of trace functions is isomorphic to the Kauffman skein algebra at

A=-1

of the thickened surface.
Comparison of satellite microwave backscattering (ASCAT) and visible/near-infrared reflectances (PARASOL) for the estimation of aeolian aerodynamic roughness length in arid and semi-arid regions
Authors: Prigent C. , Jiménez C. , Catherinot J.
Published: April 2012

Abstract. Previous studies examined the possibility to estimate the aeolian aerodynamic roughness length from satellites, either from visible/near-infrared observations or from microwave backscattering measurements. Here we compare the potential of the two approaches and propose to merge the two sources of information to benefit from their complementary aspects, i.e. the high spatial resolution of the visible/near-infrared (PARASOL part of the A-Train) and the independence from atmospheric contamination of the active microwaves (ASCAT on board MetOp). A global map of the aeolian aerodynamic roughness length at 6 km resolution is derived, for arid and semi-arid regions. It shows very good consistency with the existing information on the properties of these surfaces. The dataset is available to the community, for use in atmospheric dust transport models.
Global propagation features of large-scale traveling ionospheric disturbances during the magnetic storm of 7~10 November 2004
Authors: Song Q. , Ding F. , Wan W. , Ning B. , Liu L.
Published: April 2012

Abstract. Larger-scale traveling ionospheric disturbances (LSTIDs) were studied using the total electron content (TEC) data observed from global GPS network in the regions of North America, Europe, and East Asia during the magnetic storm of 7~10 November 2004. 4 LSTID events were detected in North America, 4 in Europe, and 3 in East Asia. The parameters of the 11 LSTID events, such as the propagation azimuth (the angle with respect to north, taking clockwise as positive), horizontal phase velocity and damping rate were determined. Our results showed two new propagation features of the LSTIDs. One was the latitudinal dependence of the LSTIDs' propagation azimuths. The LSTIDs tended to deflect more to west from south as they propagated to lower latitudes, which indicated that the Coriolis force was one of the main causes of the LSTIDs' southwestward deviation. The other was the different mean horizontal phase velocities of LSTIDs among different regions. The mean horizontal phase velocity of LSTIDs was 422 ± 36 m s−1 in North America, 381 ± 69 m s−1 in Europe, and 527 ± 21 m s−1 in East Asia, respectively. The results also indicated that the amplitudes of LSTIDs decreased during their propagation for every event, and the daytime damping rates were more than 1 time larger than the nighttime ones due to different ion drag between daytime and nighttime. The source regions of the LSTIDs were likely to be located between geomagnetic latitudes of 68° N and 62° N in North America, and between 65° N and 57° N in Europe, according to the variation of magnetic H component observed in these two regions.
Soil moisture control over autumn season methane flux, Arctic Coastal Plain of Alaska
Authors: Sturtevant C. S. , Oechel W. C. , Zona D. , Kim Y. , Emerson C. E.
Published: April 2012

Abstract. Accurate estimates of annual budgets of methane (CH4) efflux in arctic regions are severely constrained by the paucity of non-summer measurements. Moreover, the incomplete understanding of the ecosystem-level sensitivity of CH4 emissions to changes in tundra moisture makes prediction of future CH4 release from the Arctic extremely difficult. This study addresses some of these research gaps by presenting an analysis of eddy covariance and chamber measurements of CH4 efflux and supporting environmental variables during the autumn season and associated beginning of soil freeze-up at our large-scale water manipulation site near Barrow, Alaska (the Biocomplexity Experiment). We found that the autumn season CH4 emission is significant (accounting for 21–25% of the average growing season emission), and that this emission is mostly controlled by the fraction of inundated landscape, atmospheric turbulence, and the decline in unfrozen water during the period of soil freezing. Drainage decreased autumn CH4 emission by a factor of 2.4 compared to our flooded treatment. Flooding slowed the soil freezing process which has implications for extending elevated CH4 emissions longer into the winter season.
Threshold of carbonate saturation state determined by CO2 control experiment
Authors: Yamamoto S. , Kayanne H. , Terai M. , Watanabe A. , Kato K. , Negishi A. , Nozaki K.
Published: April 2012

Abstract. Acidification of the oceans by increasing anthropogenic CO2 emissions will cause a decrease in biogenic calcification and an increase in carbonate dissolution. Previous studies have suggested that carbonate dissolution will occur in polar regions and in the deep sea where saturation state with respect to carbonate minerals (Ω) will be <1 by 2100. Recent reports demonstrate nocturnal carbonate dissolution of reefs, despite a Ωa (aragonite saturation state) value of >1. This is probably related to the dissolution of reef carbonate (Mg-calcite), which is more soluble than aragonite. However, the threshold of Ω for the dissolution of natural sediments has not been clearly determined. We designed an experimental dissolution system with conditions mimicking those of a natural coral reef, and measured the dissolution rates of aragonite in corals, and of Mg-calcite excreted by other marine organisms, under conditions of Ωa > 1, with controlled seawater pCO2. The experimental data show that dissolution of bulk carbonate sediments sampled from a coral reef occurs at Ωa values of 3.7 to 3.8. Mg-calcite derived from foraminifera and coralline algae dissolves at Ωa values between 3.0 and 3.2, and coralline aragonite starts to dissolve when Ωa = 1.0. We show that nocturnal carbonate dissolution of coral reefs occurs mainly by the dissolution of foraminiferans and coralline algae in reef sediments.
The Jena Diversity-Dynamic Global Vegetation Model (JeDi-DGVM): a diverse approach to representing terrestrial biogeography and biogeochemistry based on plant functional trade-offs
Authors: Pavlick R. , Drewry D. T. , Bohn K. , Reu B. , Kleidon A.
Published: April 2012

Abstract. Dynamic Global Vegetation Models (DGVMs) typically abstract the immense diversity of vegetation forms and functioning into a relatively small set of predefined semi-empirical Plant Functional Types (PFTs). There is growing evidence, however, from the field ecology community as well as from modelling studies that current PFT schemes may not adequately represent the observed variations in plant functional traits and their effect on ecosystem functioning. In this paper, we introduce the Jena Diversity DGVM (JeDi-DGVM) as a new approach to global vegetation modelling with a richer representation of functional diversity than traditional modelling approaches based on a small number of fixed PFTs. JeDi-DGVM simulates the performance of a large number of randomly-generated plant growth strategies (PGSs), each defined by a set of 15 trait parameters which characterize various aspects of plant functioning including carbon allocation, ecophysiology and phenology. Each trait parameter is involved in one or more functional trade-offs. These trade-offs ultimately determine whether a PGS is able to survive under the climatic conditions in a given model grid cell and its performance relative to the other PGSs. The biogeochemical fluxes and land-surface properties of the individual PGSs are aggregated to the grid cell scale using a mass-based weighting scheme. Simulated global biogeochemical and biogeographical patterns are evaluated against a variety of field and satellite-based observations following a protocol established by the Carbon-Land Model Intercomparison Project. The land surface fluxes and vegetation structural properties are reasonably well simulated by JeDi-DGVM, and compare favorably with other state-of-the-art terrestrial biosphere models. This is despite the parameters describing the ecophysiological functioning and allometry of JeDi-DGVM plants evolving as a function of vegetation survival in a given climate, as opposed to typical approaches that fix land surface parameters derived from observational datasets for each PFT. The approach implemented here in JeDi-DGVM sets the foundation for future applications that will explore the impacts of explicitly resolving diverse plant communities, allowing for a more flexible temporal and spatial representation of the structure and function of the terrestrial biosphere.
A semi-analytical solution to accelerate spin-up of a coupled carbon and nitrogen land model to steady state
Authors: Xia J. , Luo Y. , Wang Y.-P. , Weng E. , Hararuk O.
Published: April 2012

Abstract. The spin-up of land models to steady state of coupled carbon-nitrogen processes is computationally so costly that it becomes a~bottleneck issue for global analysis. In this study, we introduced a semi-analytical solution (SAS) for the spin-up issue. SAS is fundamentally based on the analytic solution to a set of equations that describe carbon transfers within ecosystems over time. SAS is implemented by three steps: (1) having an initial spin-up with prior pool-size values until net primary productivity (NPP) reaches steady state, (2) calculating quasi steady-state pool sizes by letting fluxes of the equations equal zero, and (3) having a final spin-up to meet the criterion of steady state. Step 2 is enabled by averaged time-varying variables over one period of repeated driving forcings. SAS was applied to both site-level and global scale spin-up of the Australian Community Atmosphere Biosphere Land Exchange (CABLE) model. For the carbon-cycle-only simulations, SAS saved 95.7% and 92.4% of computational time for site-level and global spin-up, respectively, in comparison with the traditional method. For the carbon-nitrogen-coupled simulations, SAS reduced computational cost by 84.5% and 86.6% for site-level and global spin-up, respectively. The estimated steady-state pool sizes represent the ecosystem carbon storage capacity, which was 12.1 kg C m−2 with the coupled carbon-nitrogen global model, 14.6% lower than that with the carbon-only model. The nitrogen down-regulation in modeled carbon storage is partly due to the 4.6% decrease in carbon influx (i.e., net primary productivity) and partly due to the 10.5% reduction in residence times. This steady-state analysis accelerated by the SAS method can facilitate comparative studies of structural differences in determining the ecosystem carbon storage capacity among biogeochemical models. Overall, the computational efficiency of SAS potentially permits many global analyses that are impossible with the traditional spin-up methods, such as ensemble analysis of land models against parameter variations.
Factors affecting the runoff coefficient
Authors: Del Giudice G. , Padulano R. , Rasulo G.
Published: April 2012

Abstract. The runoff coefficient φ is a crucial parameter for flood peak discharge estimate in ungauged drainage basins. Tables and graphs generally allow the determination of φ in a somewhat empirical way that can lead to inconsistency in application; therefore, it is important to identify other parameters that can be utilized to assess φ more directly. In the present paper, focusing on Southern Continental Italy, a simple analytical expression between runoff coefficient φ and soil potential maximum retention S is proposed; moreover, an improvement of this expression is provided by considering the pre-event moisture condition of the watershed through the use of a climatic factor. At this aim, the US Soil Conservation Service classification for soil permeability has been adopted, that allows the evaluation of S, according to its relationship with the runoff curve number CN, as a function of soil type, land use and antecedent soil moisture condition (AMC).
Shear wave splitting as a proxy for stress forecast of the case of the 2006 Manyas-Kus Golu (Mb = 5.3) earthquake
Authors: Polat G. , Ozel N. M. , Crampin S. , Ergintav S. , Tan O.
Published: April 2012

Abstract. The 2006 Mb = 5.3 Manyas-Kus Golu (Manyas) earthquake has been retrospectively "stress-forecasted" using variations in time-delays of seismic shear wave splitting to evaluate the time and magnitude at which stress-modified microcracking reaches fracture criticality within the stressed volume where strain is released. We processed micro earthquakes recorded by 29 TURDEP (Multi-Disciplinary Earthquake Research in High Risk Regions of Turkey) and 33 KOERI (Kandilli Observatory and Earthquake Research Institute) stations in the Marmara region by using the aspect-ratio cross-correlation and systematic analysis of crustal anisotropy methods. The aim of the analysis is to determine changes in delay-times, hence changes in stress, before and after the 2006 Manyas earthquake. We observed that clear decreases in delay times before the impending event, especially at the station GEMT are consistent with the anisotropic poro-elasticity (APE) model of fluid-rock deformation, but we could not observe similar changes at other stations surrounding the main event. The logarithms of the duration of the stress-accumulation are proportional (self-similar) to the magnitude of the impending event. Although time and magnitude of th 2005 Manyas earthquake could have been stress-forecasted, as has been recognized elsewhere, shear-wave splitting does not appear to provide direct information about the location of impending earthquakes.
Linking the actors and policies throughout the disaster management cycle by "Agreement on Objectives" – a new output-oriented management approach
Authors: Greiving S. , Pratzler-Wanczura S. , Sapountzaki K. , Ferri F. , Grifoni P. , Firus K. , Xanthopoulos G.
Published: April 2012

Abstract. Current management of disaster risks is often fragmented due to a lack of coordination between involved actors, i.e. civil protection and spatial planning – a phenomenon which is known as the "problem of interplay". This paper presents an output-oriented risk management approach ("parametric governance"). Here, the modality of the achievement of objectives remains in the hands of the given addressees. This implies a shift from a top-down to a more collaborative, process-oriented form of decision-making. The approach has been successfully applied in two hazard cases and three administrative contexts: (a) the City of Dortmund (Germany) facing flash floods, (b) East Attica region (Greece) facing forest fires, and (c) Lazio Region (Italy) also facing forest fires. As proved by the applications of the concept, a dialogue among experts, stakeholders, and decision-makers is indispensable in order to guarantee inclusion of all diverse and competing values, opinions, and claims. Moreover, a structured communication path is needed to meet the requirements of a risk governance process. Finally, a win-win-situation among the involved actors has to be created to reach an agreement on common goals and actions to achieve them in due time.
Wave climate in the Arkona Basin, the Baltic Sea
Authors: Soomere T. , Weisse R. , Behrens A.
Published: April 2012

Abstract. The basic features of the wave climate in the Southwestern Baltic Sea (such as the average and typical wave conditions, frequency of occurrence of different wave parameters, variations in wave heights from weekly to decadal scales) are established based on waverider measurements at the Darss Sill in 1991–2010. The measured climate is compared with two numerical simulations with the WAM wave model driven by downscaled reanalysis of wind fields for 1958–2002 and by adjusted geostrophic winds for 1970–2007. The wave climate in this region is typical for semi-enclosed basins of the Baltic Sea. The maximum wave heights are about half of those in the Baltic Proper. The maximum recorded significant wave height HS =4.46 m occurred on 3 November 1995. The wave height exhibits no long-term trend but reveals modest interannual (about 12 % of the long-term mean of 0.76 m) and substantial seasonal variation. The wave periods are mostly concentrated in a narrow range of 2.6–4 s. Their distribution is almost constant over decades. The role of remote swell is very small.
The fate of fluids released from subducting slab in northern Cascadia
Authors: Ramachandran K. , Hyndman R. D.
Published: April 2012

Abstract. Large amounts of water carried down in subduction zones are driven upward into the overlying forearc upper mantle and crust as increasing temperatures and pressure dehydrate the subducting crust. Through seismic tomography velocities we show (a) the overlying forearc mantle in northern Cascadia is hydrated to serpentinite, and (b) there is low Poisson's ratio at the base of the forearc lower crust that may represent silica deposited from the rising fluids. From the velocities observed in the forearc mantle, the volume of serpentinite estimated is ∼30 %. This mechanically weak hydrated forearc region has important consequences in limits to great earthquakes and to collision tectonics. An approximately 10 km thick lower crustal layer of low Poisson's ratio (σ = 0.22) in the forearc is estimated to represent a maximum addition of ∼14 % by volume of quartz (σ = 0.09). If this quartz is removed from rising silica-saturated fluids over long times, it represents a significant addition of silica to the continental crust and an important contributor to its average composition.
Surface and snowdrift sublimation at Princess Elisabeth station, East Antarctica
Authors: Thiery W. , Gorodetskaya I. V. , Bintanja R. , van Lipzig N. P. M. , van den Broeke M. R. , Reijmer C. H. , Kuipers Munneke P.
Published: April 2012

Abstract. In the near-coastal regions of Antarctica, a significant fraction of the snow precipitating onto the surface is removed again through sublimation – either directly from the surface or from drifting snow particles. Meteorological observations from an Automatic Weather Station (AWS) near the Belgian research station Princess Elisabeth in Dronning Maud Land, East-Antarctica, are used to study surface and snowdrift sublimation and to assess their impacts on both the surface mass balance and the surface energy balance. Comparison to three other AWSs in Dronning Maud Land shows that sublimation has a significant influence on the surface mass balance at katabatic locations by removing 10–23 % of their total precipitation, but at the same time reveals anomalously low surface and snowdrift sublimation rates at Princess Elisabeth (18 mm w.e. yr–1 compared to 42 mm w.e. yr–1 at Svea Cross and 52 mm w.e. yr–1 at Wasa/Aboa). This anomaly is attributed to local topography, which shields the station from strong katabatic influence, and therefore on the one hand allows for a strong surface inversion to persist throughout most of the year and on the other hand causes a lower probability of occurrence of intermediately strong winds. These wind speed classes turn out to contribute most to the total snowdrift sublimation mass flux, given their ability to lift a high number of particles while still allowing for considerable undersaturation.
Outcome of Fetuses with Diagnosis of Isolated Short Femur in the Second Half of Pregnancy
Authors: Morales-Roselló José , Peralta LLorens Núria
Published: April 2012

Objectives. To assess the outcome of fetuses with isolated short femur detected at 19–41 weeks and determine to what extent this incidental finding should be a cause of concern in fetuses with a normal previous follow-up. Methods. 156 fetuses with isolated short femur were compared with a control group of 637 fetuses with normal femur length. FL values were converted into Z-scores and classified into 4 groups: control group: Z-score over −2, group 1: Z-score between −2 and −3, group 2: Z-score between −3 and −4, and group 3: Z-score below −4. FL values were plotted with the curves representing Z-scores −2, −3, and −4. To assess fetal outcome, the frequency of SGA, IUGR, abnormal umbilical Doppler (AUD), Down’s syndrome, and skeletal dysplasia was determined for each group after delivery, and the relative risk in comparison with the control group was obtained. Finally, ROC curves were drawn in order to evaluate the FL diagnostic ability for the conditions appearing with increased frequency. Results. SGA, IUGR, and AUD were more frequent in the fetuses with short femur. Conversely, none of them presented Down’s syndrome or skeletal dysplasia. According to ROC analysis, FL measurement behaved as a good diagnostic test for SGA and IUGR. Conclusions. A short femur diagnosis in a fetus with an otherwise normal follow-up determines just a higher risk of being small (SGA or IUGR).
Periodontal Status amongst Substance Abusers in Indian Population
Authors: Reddy Shantipriya , Kaul Sanjay , Agrawal Chaitali , Prasad M. G. S. , Agnihotri Jaya , Bhowmik Nirjhar , Amudha D. , Kambali Soumya
Published: April 2012

Background. In India there have been limited number of studies on periodontal status among drug addicts, and thus this study aims to assess the Oral hygiene and periodontal status in substance abusers and compare it with non-substance abusers. Methods. A comparative study was conducted to assess the periodontal status in substance abusers. Non-substance abusers were procured from the general population of Bangalore. From the control group 250 non-substance abusers were age and sex matched with the study population of substance abusers. The oral hygiene and periodontal condition of all subjects was assessed using Oral hygiene index- simplified (OHI-S), Russell's periodontal indices and Gingival bleeding index. Results. The mean of OHI-S and Periodontal Index (Russell's Index) scores were higher (2.70 and 3.68, resp.) in substance abusers than the control group (2.45 and 2.59, resp.). The mean Gingival bleeding score was lower (9.69) in substance abusers than the control group (22.7) and found to be statistically significant. A positive correlation found between OHI-S and Russell's periodontal index whereas negative correlation was found between OHI-S and Gingival bleeding in substance abusers. Conclusions. Though the oral hygiene was fair, more periodontal destruction and less of gingival bleeding were observed in substance abusers as compared to control group.
Apoptosis: Reprogramming and the Fate of Mature Cells
Authors: Cheung Hoi-Hung , Liu Xiaozhuo , Rennert Owen M.
Published: April 2012

Apoptosis is essential for embryogenesis, organ metamorphosis, and tissue homeostasis. In embryonic stem cells, self-renewal is balanced with proliferative potential, inhibition of differentiation, and prevention of senescence and apoptosis. Growing evidence supports the role of apoptosis in self-renewal, differentiation of pluripotent stem cells, and dedifferentiation (reprogramming) of somatic cells. In this paper we discuss the multiple roles of apoptosis in embryonic stem cells (ESCs) and reprogramming of differentiated cells to pluripotency. The role of caspases and p53 as key effectors in controlling the generation of iPSC is emphasized. Remarkably, the complication of apoptosis arising during reprogramming may provide insights into technical improvements for derivation of iPSC from senescent cells as a tool for modeling aging-related diseases.
Effect of Some Manfacturing Parameters on Machining of Extruded Al-Al2O3 Composites
Authors: Fathy A. , Abdelhameed M. , Shehata F.
Published: April 2012

A wide range of particulate metal matrix composites (PMMCs) of alumina and aluminum powders was formed using powder metallurgy techniques followed by extrusions at various extrusion ratios. The machining characteristics of the extruded PMMC were investigated. Results showed significant effects of weight fractions of reinforcement and extrusion ratios on tool wear and surface integrity of machined surface. The wear rate of cutting tool decreased rapidly with increasing the cutting parameters: cutting speed, feed, and depth of cut, however cutting speed is shown to be more effective. Sudden breakage of tool inserts occurred when the experiment started at high cutting speed. Wear rate has also decreased by decreasing volume fraction of reinforcement particles. Coating carbide tools have significantly improved the tool life. Coated tools showed 5% decrease in flank wear size compared to uncoated tools. This was valid within tested range of weight fractions and extrusion ratios. The surface finish of machined surfaces deteriorated when coated carbide tools were used. However, surface finish did not change significantly when volume fractions or extrusion ratios were altered.
Effects of Pythium Species and Time in Cold Storage on the Survival of Bareroot and Container-Grown Southern Pine Seedlings
Authors: Jackson D. Paul , Enebak Scott A. , South David B.
Published: April 2012

Cold storing bareroot southern pine (Pinus spp.) seedlings for greater than one week after lifting in the fall can lead to poor outplanting survival when compared to seedlings that are lifted and stored in winter. In contrast, container-grown seedlings typically do not experience adverse effects from storing for periods greater than one week. The practice of lifting bareroot seedlings can cause wounds to root systems, which could allow soil-borne pathogens such as Pythium species to be used as infection sites. Once seedlings are placed in storage, the cool, moist environment may be conducive for zoospore activity, leading to root disease and outplanting failure. Bareroot and container-grown longleaf pine (Pinus palustris), loblolly pine (Pinus taeda), and slash pine (Pinus elliottii) and container-grown shortleaf pine (Pinus echinata) were inoculated with either Pythium dimorphum or Pythium irregulare, cold-stored for 3, 4, 6, or 12 weeks, and outplanted. Both Pythium species reduced survival of bareroot longleaf pine but not bareroot slash pine. Length of storage decreased survival for both seedling stock types. Pythium species did not affect the survival of container-grown seedlings. These results suggest that P. dimorphum and P. irregulare are more virulent to bareroot longleaf pine than the other pine species tested.
Dart and Arrow Points on the Columbia Plateau of Western North America
Authors: Ames Kenneth M. , Fuld Kristen A. , Davis Sara
Published: April 2012

The timing of the bow and arrow's introduction, spread, and replacement of the atlatl is an important research question in North American prehistory. Although regional archaeologists have not focused on the issue, it is generally thought that the bow and arrow were introduced on the Columbia Plateau ca. 2,300 years ago and completely replaced the atlatl by 1000 B.P. We apply two sets of discriminate functions and four threshold values to three large projectile point samples from the Columbia Plateau and a control sample from the Western Great Basin. Our results indicate that the atlatl was used on the Plateau by ca. 10,800 B.P. While the bow and arrow may have been present by 8500 B.P., they were ubiquitous in the region by 4400 B.P. Atlatl use appears to have increased for a while after 3000 B.P. At the same time, metric differences between dart and arrow points strengthened. Darts became rare after 1500 B.P. but seem to have been in use in small numbers at least until contact.
Placing the Poverty Point Mounds in their Temporal Context
Authors: Ortmann Anthony L.
Published: April 2012

Sampling biases in archaeological research may inadvertently lead to unsubstantiated assumptions about the relationship between various site features. The majority of radiometric dates from the Poverty Point site have been recovered from excavations in the large, earthen ridges. While archaeological investigations have previously been undertaken in the Poverty Point mounds, few of these excavations have yielded radiometric dates. As a result of the almost complete absence of chronometric data from Poverty Point's mounds, the construction of these features is generally assumed to have occurred during the same time span as construction of the ridges. New radiometric dates from the Poverty Point mounds reveal information about the timing and pace of their construction. These new chronological data provide the basis for a more detailed developmental sequence, and may allow for the development of new hypotheses about population size, the organization of labor, architectural relationships, and the degree of social complexity at Poverty Point. Examining the development of cultural landscapes, such as the chronology of earthwork construction at Poverty Point, also provides a better understanding of the ways prehistoric societies interacted with and modified the environments in which they lived.
The Clovis Occupation of the Dietz Site (35LK1529), Lake County, Oregon, and its Bearing on the Adaptive Diversity of Clovis Foragers
Authors: Pinson Ariane O.
Published: April 2012

Archaeological models of Clovis adaptations are divided between those that argue for a single hunting adaptation characterized by high residential mobility without fixed territories and those that argue for a diversity of environment-specific adaptations and settlement systems. The Dietz site (35LK1529), the largest Clovis site in the Pacific Northwest, is composed of many overlapping, spatially coherent artifact clusters from which 75 whole and fragmentary fluted points have been recovered. The artifact assemblage is inconsistent with use of the site as a kill, camp, or quarry site. Geoarchaeological data show that the site area during the Clovis occupation was a sparsely vegetated, seasonal playa that is unlikely to have supported large herds of game animals. However, the site sits astride what was probably a major transportation corridor linking highly productive ecosystems in the adjoining basins, and Clovis foragers appear to have camped at Dietz repeatedly while traveling between these nearby basins. The systematic and redundant use of a geographically small landscape by Clovis foragers is inconsistent with expectations based on a model of residentially mobile foragers occupying new territories.
Economic Foraging at a Distance Is Not a Question Of If but When: A Response to Grimstead
Authors: Whitaker Adrian R. , Carpenter Kimberley L.
Published: April 2012

Grimstead (2010) develops a transport model that appears to demonstrate that distant patch hunting is energetically efficient at distances of well over 350 km. However, a close examination of her assumptions raises questions concerning the validity of her approach. Here, we examine the effects of using more ecologically justifiable parameters and consider the cost of time spent away from camp on her model’s outcomes. We find that under revised constraints the model yields much shorter maximum transport distances and argue, therefore, that distant patch hunting may be calorically economical in some cases, but not in others.
Sex-Specific Phenotypic Variability and Social Organization in the Chiribaya of Southern Peru
Authors: Nystrom Kenneth C. , Malcom Christine M.
Published: April 2012

Analyses of skeletal phenotypic traits have the potential to yield information pertaining to social organization, such as kinship and residence patterns. In this research, we examine sex-specific phenotypic variability of craniofacial and mandibular metric traits in eight skeletal samples from four sites (San Gerónimo, Chiribaya Alta, Chiribaya Baja, and El Yaral) attributed to the Chiribaya polity (A.D. 772–1350) and a contemporary Ilo-Tumilaca/Cabuza group (El Algodonal) from southern Peru. Through this data set we investigate various aspects of social organization (e.g., postmarital residence patterns) within the Chiribaya polity. We also examine Chiribaya interactions with the contemporaneous, yet culturally distinct, Tumilaca cultural group. The pattern of between-group bias-corrected estimates of biological distances points toward a more distant biological relationship between the two cultures than has previously been reported. Among the Chiribaya groups considered, determinant ratio analyses indicate that males from two cemeteries (Chiribaya Alta Cemetery 4 and Chiribaya Alta Cemetery 7) were significantly more variable than females, suggesting that males were the more mobile sex. Several explanatory models are considered, including a matrilocal residence pattern and the in-migration of males. We also examine the unique nature of results from within Chiribaya Alta, which support the argument made by previous researchers that this site represents a regional political center.
America’s First Polymer Scientists: Rubber Processing, Use and Transport in Mesoamerica
Authors: Tarkanian Michael J. , Hosler Dorothy
Published: April 2012

Ancient Mesoamericans were making rubber by at least 1600 B.C, mixing latex from Castilla elastica trees with juice from Ipomoea alba (morning glory) vines. The combination of ethnographic, archaeological and mechanical data presented in this text illustrate that ancient Mesoamericans had fully developed this process, and consciously tailored the mechanical properties of rubber to suit requirements of specific applications by altering the ratio of latex to I. alba juice. Our data focus on rubber balls, sandal soles, and rubber bands for hafting and joining. Elasticity, the mechanical property that defines the ability of a rubber ball to bounce, is maximized with a 1:1 volume ratio of latex to I. alba juice. Rubber with high wear resistance, vital to the life and functionality of a sandal sole, can be created by mixing C. elastica latex with 25 percent I. alba juice by volume. Unprocessed C. elastica latex, without I. alba juice, is the material best suited for joining applications, such as adhesives or hafting bands, where strength and ability to absorb shock is of the greatest importance. Tribute data from sixteenth-century codices substantiate that rubber was processed for specific applications within the Aztec empire—rubber and latex goods were processed and constructed in the C. elastica-bearing regions, and then shipped to the capital for use or further distribution.
Association of obesity with worse disease severity in rheumatoid arthritis as well as with comorbidities: A long‐term followup from disease onset
Authors: Ajeganova Sofia , Andersson Maria L. , Hafström Ingiäld ,   for the BARFOT Study Group
Published: April 2012

Objective

To determine the association of obesity, defined as a body mass index (BMI) ≥30 or ≥28 kg/m2 or by waist circumference (WC), with disease activity and severity, as well as its relationship to comorbidities in rheumatoid arthritis (RA).

Methods

The study population comprised 1,596 patients with early RA (mean ± SD age 55.6 ± 14.6 years, 67.8% women) who had been included in the Better Anti‐Rheumatic Farmacotherapy observational study from 1992–2006. In 2010, data on lifestyle factors and comorbidities were collected through a postal questionnaire, answered by 1,391 patients. Clinical outcomes were the Disease Activity Score in 28 joints, sustained remission, physical function (Health Assessment Questionnaire [HAQ]), and pain and global health assessed on a visual analog scale, as well as predefined comorbidities.

Results

After a mean ± SD of 9.5 ± 3.7 years, the mean ± SD BMI had increased from 25.4 ± 4.2 to 26.0 ± 4.5 kg/m2 (P = 0.000). The prevalence of BMI ≥30 kg/m2 was 12.9% at baseline and 15.8% at followup. In multivariable regression, BMI and obesity, defined as a BMI ≥30 or ≥28 kg/m2, at both inclusion and the time of the survey were independently associated with higher disease activity, fewer patients in sustained remission, higher HAQ score, more pain, and worse general health. Also, BMI and obesity independently conferred to higher odds for being diagnosed with hypertension, diabetes mellitus, and chronic pulmonary disease. Further, BMI and WC were independently associated with angina pectoris/acute myocardial infarction/coronary revascularization. In contrast, none of the examined obesity variables was associated with the prevalence of stroke or transient ischemic attack. Lifestyle changes during the observational period, such as quitting smoking or diet change, had no impact on the outcomes.

Conclusion

Obesity was associated with worse RA disease outcomes and a higher prevalence of comorbidities. Body measurements are recommended to improve prediction of the disease course.
Association between polymyalgia rheumatica and vascular disease: A systematic review
Authors: Hancock Adam T. , Mallen Christian D. , Belcher John , Hider Samantha L.
Published: April 2012

Objective

To systematically identify and appraise the existing literature on the association between polymyalgia rheumatica (PMR) and vascular disease.

Methods

The Medline, Embase, CINAHL, and Cochrane databases were searched from inception to September 2010. Search criteria included observational studies containing patients with isolated PMR reporting on a vascular outcome. Data were extracted and articles were assessed for quality.

Results

The database search identified 545 articles. Eight articles reporting on 7 unique studies were included in the final review. Four studies reported on vascular mortality and 3 studies reported on other vascular outcomes. Four of the studies reported statistically significant positive associations between PMR and vascular disease and 3 studies reported no statistically significant results. The heterogeneity of the results was investigated; the strongest explanatory variable was that 2 of 3 studies that reported nonsignificant results were prospective, whereas all of those studies reporting significant results were retrospective.

Conclusion

There is some evidence to suggest that, like other inflammatory rheumatic disorders, PMR may be linked to an increased risk of vascular disease. Further studies are required to quantify the level of risk to determine whether patients with PMR should be actively screened for cardiovascular disease and its risk factors.
Template‐Assisted Synthesis of π‐Conjugated Molecular Organic Nanowires in the Sub‐100 nm Regime and Device Implications
Authors: Alam Kazi M. , Singh Abhay P. , Starko‐Bowes Ryan , Bodepudi Srikrishna C. , Pramanik Sandipan
Published: April 2012

π‐conjugated molecular organics such as rubrene, Alq3, fullerene, and PCBM have been used extensively over the last few decades in numerous organic electronic devices, including solar cells, thin‐film transistors, and large‐area, low‐cost flexible displays. Rubrene and Alq3, have emerged as promising platforms for spin‐based classical and quantum information processing, which has triggered significant research activity in the relatively new area of organic spintronics. Synthesis of these materials in a nanowire geometry, with feature sizes in the sub‐100 nm regime, is desirable as it often enhances device performance and is essential for development of high‐density molecular electronic devices. However, fabrication techniques that meet this stringent size constraint are still largely underdeveloped. Here, a novel, versatile, and reagentless method that enables growth of nanowire arrays of the above‐mentioned organics in the cylindrical nanopores of anodic aluminum oxide (AAO) templates is demonstrated. This method 1) allows synthesis of high‐density organic nanowire arrays on arbitrary substrates, 2) provides electrical access to the nanowire arrays, 3) offers tunability of the array geometry in a range overlapping with the relevant physical length scales of many organic devices, and 4) can potentially be extended to synthesize axially and radially heterostructured organic nanowires. Thus prepared nanowires are characterized extensively with an aim to identify their potential applications in diverse areas such as organic optoelectronics, photovoltaics, molecular nanoelectronics, and spintronics.
A Facile Microwave Avenue to Electrochemiluminescent Two‐Color Graphene Quantum Dots
Authors: Li Ling‐Ling , Ji Jing , Fei Rong , Wang Chong‐Zhi , Lu Qian , Zhang Jian‐Rong , Jiang Li‐Ping , Zhu Jun‐Jie
Published: April 2012

With the assistance of microwave irradiation, greenish‐yellow luminescent graphene quantum dots (gGQDs) with a quantum yield (QY) up to 11.7% are successfully prepared via cleaving graphene oxide (GO) under acid conditions. The cleaving and reduction processes are accomplished simultaneously using microwave treatment without additional reducing agent. When the gGQDs are further reduced with NaBH4, bright blue luminescent graphene quantum dots (bGQDs) are obtained with a QY as high as 22.9%. Both GQDs show well‐known excitation‐dependent PL behavior, which could be ascribed to the transition from the lowest unoccupied molecular orbital (LUMO) to the highest occupied molecular orbital (HOMO) with a carbene‐like triplet ground state. Electrochemiluminescence (ECL) is observed from the graphene quantum dots for the first time, suggesting promising applications in ECL biosensing and imaging. The ECL mechanism is investigated in detail. Furthermore, a novel sensor for Cd2+ is proposed based on Cd2+ induced ECL quenching with cysteine (Cys) as the masking agent.
High‐Performance Top‐Gated Organic Field‐Effect Transistor Memory using Electrets for Monolithic Printed Flexible NAND Flash Memory
Authors: Baeg Kang‐Jun , Khim Dongyoon , Kim Juhwan , Yang Byung‐Do , Kang Minji , Jung Soon‐Won , You In‐Kyu , Kim Dong‐Yu , Noh Yong‐Young
Published: April 2012

High‐performance top‐gated organic field‐effect transistor (OFET) memory devices using electrets and their applications to flexible printed organic NAND flash are reported. The OFETs based on an inkjet‐printed p‐type polymer semiconductor with efficiently chargeable dielectric poly(2‐vinylnaphthalene) (PVN) and high‐k blocking gate dielectric poly(vinylidenefluoride‐trifluoroethylene) (P(VDF‐TrFE)) shows excellent non‐volatile memory characteristics. The superior memory characteristics originate mainly from reversible charge trapping and detrapping in the PVN electret layer efficiently in low‐k/high‐k bilayered dielectrics. A strategy is devised for the successful development of monolithically inkjet‐printed flexible organic NAND flash memory through the proper selection of the polymer electrets (PVN or PS), where PVN/‐ and PS/P(VDF‐TrFE) devices are used as non‐volatile memory cells and ground‐ and bit‐line select transistors, respectively. Electrical simulations reveal that the flexible printed organic NAND flash can be possible to program, read, and erase all memory cells in the memory array repeatedly without affecting the non‐selected memory cells.