bluuebunny/crossref_metadata_2025_split huggingface dataset:
FISH RESPONSE TO ANTHROPOGENIC PRESSURES IN TEMPORARY STREAMS: THE IMPORTANCE OF ENVIRONMENTAL DRIVERS
Authors: Matono P. , Bernardo J. M. , Costa A. M. , Ilhéu M. 
Published: June 2014

ABSTRACTMediterranean temporary streams show high spatial and temporal heterogeneity. Native fish species are adapted to this natural variability, but the cumulative effect of natural and anthropogenic disturbances may compromise the stability and persistence of fish assemblages. This study aimed to determine if environmental drivers affect the response of fish assemblages to anthropogenic pressures in temporary streams and identify what type of fish assemblages are particularly vulnerable to anthropogenic disturbance. Data were collected from 22 sites located in southern Portuguese temporary streams between 1996 and 2012. The temporal pattern of fish assemblages in each site was used to examine fish assemblage stability, that is, the relative constancy of species abundance over time, quantified using the Bray–Curtis similarity coefficient. Native fish assemblage stability was positively associated with altitude, annual rainfall, percentage of riffles and habitat diversity and highly negatively related to anthropogenic pressure, particularly land use intensification, riparian degradation, sediment load and organic contamination/nutrient enrichment. Results highlighted an interaction between natural environmental and anthropogenic pressure gradients; anthropogenic disturbance tends to be lower in high‐elevation headwater streams and increases in lowland streams, particularly in downstream reaches. In upstream reaches, especially in lowland streams, fish assemblage stability showed a steep decline with the increase in anthropogenic pressure. Lowland downstream reaches displayed a less steep decline of fish assemblage stability in response to degradation, despite having greater anthropogenic disturbance. The results highlight the particular vulnerability of headwater streams in lowland sectors to anthropogenic disturbance. Copyright © 2014 John Wiley & Sons, Ltd.
Estimation of Sediment Hydraulic Conductivity in River Reaches and its Potential Use to Evaluate Streambed Clogging
Authors: Datry T. , Lamouroux N. , Thivin G. , Descloux S. , Baudoin J. M. 
Published: June 2014

AbstractStreambed substrates have pervasive effects on stream biodiversity and biogeochemistry. The excessive input of fine sediments in streams and the subsequent alteration of the physical characteristics of streambed substrates are considered today as a major environmental issue. The estimation of streambed hydraulic conductivity (K) may be simpler than other estimations of reach‐scale physical characteristics and could serve to quantify the alterations of streambeds across stream networks. In this study, we examined between‐reach and within‐reach variability and temporal changes of streambed K across 101 stream reaches in France, including nine reaches previously judged as clogged and nine as references (unclogged). We also examined the relationships between K and some environmental variables such as vertical hydraulic gradient, streambed grain size, flow velocity or distance to the bank. We demonstrated that 15 measurements of streambed K per reach could be used to compare streams among each other and over time. Clogged reaches displayed much lower K than reference reaches, and more generally, reach‐averaged K and the number of non‐null K values per reach allowed discriminating reaches among each other without observer bias. K was higher in upwelling compared with downwelling areas, probably because of fine sediment uplifting. With the low cost in terms of equipment (<€100 per unit) and time (2–4 h per site), reach‐scale streambed K estimates are promising for studying the alterations of streambed substrates across stream monitoring networks such as clogging, but also for understanding large‐scale drivers of these alterations, or for upscaling recent developments in hyporheic ecology at the reach scale. Copyright © 2014 John Wiley & Sons, Ltd.
The Hydrological Status Concept: Application at a Temporary River (Candelaro, Italy)
Authors: De Girolamo A. M. , Lo Porto A. , Pappagallo G. , Tzoraki O. , Gallart F. 
Published: June 2014

AbstractIn achieving the final objective of the European Water Framework Directive, the evaluation of the ‘hydrological status’ of a water body in a catchment is of the utmost importance. It represents the divergence of the actual hydrological regime from its ‘natural’ condition and may thus provide crucial information about the ecological status of a river. In this paper, a new approach in evaluating the hydrological status of a temporary river was tested. The flow regime of a river has been classified through the analysis of two metrics: the permanence of flow and the predictability of no‐flow conditions that were evaluated on monthly streamflow data. This method was applied to the Candelaro river basin (Puglia, Italy) where we had to face the problem of limited data availability. The Soil and Water Assessment Tool model was used when streamflow data were not available, and a geographic information system procedure was applied to estimate potential water abstractions from the river. Four types of rivers were identified whose regimes may exert a control on aquatic life. By using the two metrics as coordinates in a plot, a graphic representation of the regime can be visualized in a point. Hydrological perturbations associated with water abstractions, point discharges and the presence of a reservoir were assessed by comparing the position of the two points representing the regime before and after the impacts. The method is intended to be used with biological metrics in order to define the ecological status of a stream, and it could also be used in planning the ‘measures’ aimed at fulfilling the Water Framework Directive goals. Copyright © 2014 John Wiley & Sons, Ltd.
Neural Stem Cells Differentiated From iPS Cells Spontaneously Regain Pluripotency
Authors: Choi Hyun Woo , Kim Jong Soo , Choi Sol , Hong Yean Ju , Kim Min Jung , Seo Han Geuk , Do Jeong Tae 
Published: June 2014

Abstract
Differentiated somatic cells can be reprogrammed into pluripotent stem cells by transduction of exogenous reprogramming factors. After induced pluripotent stem (iPS) cells are established, exogenous genes are silenced. In the pluripotent state, retroviral genes integrated in the host genome are kept inactive through epigenetic transcriptional regulation. In this study, we tried to determine whether exogenous genes remain silenced or are reactivated upon loss of pluripotency or on differentiation using an in vitro system. We induced differentiation of iPS cells into neural stem cells (NSCs) in vitro; the NSCs appeared morphologically indistinguishable from brain-derived NSCs and stained positive for the NSC markers Nestin and Sox2. These iPS cell-derived NSCs (iPS-NSCs) were also capable of differentiating into all three neural subtypes. Interestingly, iPS-NSCs spontaneously formed aggregates on long-term culture and showed reactivation of the Oct4-GFP marker, which was followed by the formation of embryonic stem cell-like colonies. The spontaneously reverted green fluorescent protein (GFP)-positive (iPS-NSC-GFP+) cells expressed high levels of pluripotency markers (Oct4 and Nanog) and formed germline chimeras, indicating that iPS-NSC-GFP+ cells had the same pluripotency as the original iPS cells. The reactivation of silenced exogenous genes was tightly correlated with the downregulation of DNA methyltransferases (Dnmts) during differentiation of iPS cells. This phenomenon was not observed in doxycycline-inducible iPS cells, where the reactivation of exogenous genes could be induced only by doxycycline treatment. These results indicate that pluripotency can be regained through reactivation of exogenous genes, which is associated with dynamic change of Dnmt levels during differentiation of iPS cells. Stem Cells 2014;32:2596–2604
Nrf2, a Regulator of the Proteasome, Controls Self-Renewal and Pluripotency in Human Embryonic Stem Cells
Authors: Jang Jiwon , Wang Yidi , Kim Hyung-Seok , Lalli Matthew A. , Kosik Kenneth S. 
Published: June 2014

Abstract
Nuclear factor, erythroid 2-like 2 (Nrf2) is a master transcription factor for cellular defense against endogenous and exogenous stresses by regulating expression of many antioxidant and detoxification genes. Here, we show that Nrf2 acts as a key pluripotency gene and a regulator of proteasome activity in human embryonic stem cells (hESCs). Nrf2 expression is highly enriched in hESCs and dramatically decreases upon differentiation. Nrf2 inhibition impairs both the self-renewal ability of hESCs and re-establishment of pluripotency during cellular reprogramming. Nrf2 activation can delay differentiation. During early hESC differentiation, Nrf2 closely colocalizes with OCT4 and NANOG. As an underlying mechanism, our data show that Nrf2 regulates proteasome activity in hESCs partially through proteasome maturation protein (POMP), a proteasome chaperone, which in turn controls the proliferation of self-renewing hESCs, three germ layer differentiation and cellular reprogramming. Even modest proteasome inhibition skews the balance of early differentiation toward mesendoderm at the expense of an ectodermal fate by decreasing the protein level of cyclin D1 and delaying the degradation of OCT4 and NANOG proteins. Taken together, our findings suggest a new potential link between environmental stress and stemness with Nrf2 and the proteasome coordinately positioned as key mediators. Stem Cells 2014;32:2616–2625
Analysis and design of Coleman transform‐based individual pitch controllers for wind‐turbine load reduction
Authors: Lu Q. , Bowyer R. , Jones B.Ll. 
Published: June 2014

AbstractAs the size of wind turbines increases, the effects of dynamic loading on the turbine structures become increasingly significant. There is therefore a growing demand for turbine control systems to alleviate these unsteady structural loads in addition to maintaining basic requirements such as power and speed regulation. This has motivated the development of blade individual pitch control (IPC) methodologies, many of which employ the Coleman transformation to simplify the controller design process. However, and as is shown in this paper, the Coleman transformation significantly alters the rotational system dynamics when these are referred to the non‐rotating frame of reference, introducing tilt–yaw coupling in the process. Unless this transformation is explicitly included in the model employed for IPC design, then the resulting controllers can yield poor performance. Therefore, in this paper, we show how to model the Coleman transformation in a form that is amenable to IPC analysis and synthesis. This enables us to explain why traditional design parameters of gain and phase margin are poor indicators of robust stability and hence motivate the need for a multivariable design approach. The robust multivariable IPC approach advocated in this paper is based upon
loop shaping and has numerous desirable properties, including reliable stability margins, improved tilt–yaw decoupling and simultaneous rejection of disturbance loads over a range of frequencies. The design of a robust multivariable IPC is discussed, and simulation results are presented that demonstrate the efficacy of this controller, in terms of load reduction on both rotating and non‐rotating turbine parts. Copyright © 2014 John Wiley & Sons, Ltd.
Optimising expression of the recombinant fusion protein biopesticide ω-hexatoxin-Hv1a/GNA inPichia pastoris:sequence modifications and a simple method for the generation of multi-copy strains
Authors: Pyati Prashant , Fitches Elaine , Gatehouse John A 
Published: June 2014

AbstractProduction of recombinant protein bio-insecticides on a commercial scale can only be cost effective if host strains with very high expression levels are available. A recombinant fusion protein containing an arthropod toxin, ω-hexatoxin-Hv1a, (from funnel web spider Hadronyche versuta) linked to snowdrop lectin (Galanthus nivalis agglutinin; GNA) is an effective oral insecticide and candidate biopesticide. However, the fusion protein was vulnerable to proteolysis during production in the yeast Pichia pastoris. To prevent proteolysis, the Hv1a/GNA fusion expression construct was modified by site-directed mutagenesis to remove a potential Kex2 cleavage site at the C-terminus of the Hv1a peptide. To obtain a high expressing clone of P. pastoris to produce recombinant Hv1a/GNA, a straightforward method was used to produce multi-copy expression plasmids, which does not require multiple integrations to give clones of P. pastoris containing high copy numbers of the introduced gene. Removal of the Kex2 site resulted in increased levels of intact fusion protein expressed in wild-type P. pastoris strains, improving levels of intact recombinant protein recoverable. Incorporation of a C-terminal (His)6 tag enabled single step purification of the fusion protein. These modifications did not affect the insecticidal activity of the recombinant toxin towards lepidopteran larvae. Introduction of multiple expression cassettes increased the amount of secreted recombinant fusion protein in a laboratory scale fermentation by almost tenfold on a per litre of culture basis. Simple modifications in the expression construct can be advantageous for the generation of high expressing P. pastoris strains for production of a recombinant protein, without altering its functional properties.
Sex differences in learning and memory following short‐term dietary restriction in the rat
Authors: Rajab Ebrahim , Alqanbar Batool , Naiser Mohammed J. , Abdulla Habib A. , Al‐Momen Monaf M. , Kamal Amer 
Published: June 2014

AbstractIntroductionAcute or prolonged dietary restriction has been shown to have significant effects on learning and memory, and also on the food seeking behaviour in animals.AimThis study investigated whether or not there are sex differences in spatial learning and memory following short‐term dietary restriction in the rat.MethodsTwo month‐old male (n = 24) and female (n = 24) Sprague‐Dawley rats were randomly assigned to either (1) male or female control (i.e. normal diet regimen); (2) male or female 40% dietary restriction for either 2 hours (2 h‐DR) or 2 weeks (2 wks‐DR) duration. Following the restriction paradigm (i.e. either 2 h or 2 weeks), animals were weighed, and learning and memory was assessed daily for a total of 5 days by Morris Water Maze.ResultsDietary restriction for 2 h provoked high speed swimming in female rats compared to controls. However the females performance in water maze was inferior to the control animals. Two weeks after 40% DR resulted in reduction of male's body weight by 20% compared to their control group. However, both males and females showed difficulties in water maze learning and memory test after the 2 weeks 40% DR. The animals swam longer distance and took longer time to reach the platform when compared to their age‐matched controls.ConclusionIn fully developed brain, adult animal's cognitive performance is shown to be affected by acute and prolonged stress in the form of food restriction. Interestingly, the impact of this stress was different according to the sex of the animals. In female rats, dietary restriction has a negative effect on learning and memory after 2 h and 2 weeks intervals. In male rats, 2 h of DR has a positive effect on learning and memory; however this effect is not maintained and by 2 weeks there is a negative effect similar to that seen in female animals.
Two-dimensional planar plumes: non-Boussinesq effects
Authors: van den Bremer T. S. , Hunt G. R. 
Published: June 2014

AbstractIn an accompanying paper (van den Bremer & Hunt, J. Fluid Mech., vol. 750, 2014, pp. 210–244) closed-form solutions, describing the behaviour of two-dimensional planar turbulent rising plumes from horizontal planar area and line sources in unconfined quiescent environments of uniform density, that are universally applicable to Boussinesq and non-Boussinesq plumes, are proposed. This universality relies on an entrainment velocity unmodified by non-Boussinesq effects, an assumption that is derived in the literature based on similarity arguments and is, in fact, in contradiction with the axisymmetric case, in which entrainment is modified by non-Boussinesq effects. Exploring these solutions, we show that a non-Boussinesq plume model predicts exactly the same behaviour with height for a pure plume as would a Boussinesq model, whereas the effects on forced and lazy plumes are opposing. Non-intuitively, the non-Boussinesq model predicts larger fluxes of volume and mass for lazy plumes, but smaller fluxes for forced plumes at any given height compared to the Boussinesq model. This raises significant questions regarding the validity of the unmodified entrainment model for planar non-Boussinesq plumes based on similarity arguments and calls for detailed experiments to resolve this debate.
Nonlinear control of parallel manipulators for very high accelerations without velocity measurement: stability analysis and experiments on Par2 parallel manipulator
Authors: Natal Guilherme Sartori , Chemori Ahmed , Pierrot François 
Published: June 2014

SUMMARYThis paper presents a comparison between control/state estimation methods applied on Par2 parallel manipulator for pick-and-place applications as well as a discussion about the mechanical vibrations issue that may become important when reaching very high accelerations. Real-time experiments were performed first to compare two controllers (a linear Proportional-Derivative controller and a nonlinear/adaptive Dual Mode (DM) controller) complied with the same High-Gain Observer (HGO) to estimate articular velocities, and second to compare three state observers (a Lead-lag-based, an Alpha-beta-gamma (ABG) and an HGO) complied with the same nonlinear DM controller. The stability analysis of the Par2 robot under the control of the proposed DM controller (complied with the HighGO for joint velocity estimation) is also provided. Some small mechanical vibrations were noted when reaching 20 G acceleration, which means that it can become an important issue for higher accelerations. Some suggestions are then made for future investigations to avoid/damp these vibrations.
On the control of a single flexible arm robot via Youla-Kucera parameterization
Authors: Esfandiar Habib , Daneshmand Saeed , Kermani Roozbeh Dargahi 
Published: June 2014

SUMMARYIn this paper, based on the Youla-Kucera (Y-K) parameterization, the control of a flexible beam acting as a flexible robotic manipulator is investigated. The method of Youla parameterization is the simple solution and proper method for describing the collection of all controllers that stabilize the closed-loop system. This collection comprises function of the Youla parameter which can be any proper transfer function that is stable. The main challenge in this approach is to obtain a Youla parameter with infinite dimension. This parameter is approximated by a subspace with finite dimensions, which makes the problem tractable. It is required to be generated from a finite number of bases within that space and the considered system can be approximated by an expansion of the orthonormal bases such as FIR, Laguerre, Kautz and generalized bases. To calculate the coefficients for each basis, it is necessary to define the problem in the form of an optimization problem that is solved by optimization techniques. The Linear Quadratic Regulator (LQR) optimization tool is employed in order to optimize the controller gains. The main aim in controller design is to merge the closed-loop system and the second order system with the desirable time response characteristic. The results of the Youla stabilizing controller for a planar flexible manipulator with lumped tip mass indicate that the proposed method is very efficient and robust for the time-continuous instances.
Pattern-based unsupervised parsing method
Authors: SANTAMARÍA JESÚS , ARAUJO LOURDES 
Published: June 2014

AbstractWe have developed a heuristic method for unsupervised parsing of unrestricted text. Our method relies on detecting certain patterns of part-of-speech tag sequences of words in sentences. This detection is based on statistical data obtained from the corpus and allows us to classify part-of-speech tags into classes that play specific roles in the parse trees. These classes are then used to construct the parse tree of new sentences via a set of deterministic rules. Aiming to asses the viability of the method on different languages, we have tested it on English, Spanish, Italian, Hebrew, German, and Chinese. We have obtained a significant improvement over other unsupervised approaches for some languages, including English, and provided, as far as we know, the first results of this kind for others.
Rosa de Vries: A Dutch Diva and Nineteenth-Century Trans-Atlantic Operatic Culture
Authors: METZELAAR HELEN 
Published: June 2014

AbstractIn an arduous, twenty-year international career, Dutch opera soprano Rosa de Vries née van Os (1824–89) performed both French and Italian opera repertory with leading companies on both sides of the Atlantic. Experiencing triumphs and disappointments while managing both career and family, de Vries represents a class of mid-century opera singers, celebrated in their time but little remembered today. This article tells the story of de Vries's life and career, and in doing so aims to contribute to an understanding of transatlantic operatic life at the time. This reconstruction of Rosa de Vries offers a gateway for further studies of the cultural heritage of an important period in the history of opera and the strenuous demands of an international operatic marketplace.
Topologically protected states in one-dimensional continuous systems and Dirac points
Authors: Fefferman Charles L. , Lee-Thorp James P. , Weinstein Michael I. 
Published: June 2014

Significance
Topological insulators (TIs) have been a topic of intense study in recent years. When appropriately interfaced with other structures, TIs possess robust edge states, which persist in the presence of localized interface perturbations. Therefore, TIs are ideal for the transfer or storage of energy or information. The prevalent analyses of TIs involve idealized discrete tight-binding models. We present a rigorous study of a class of continuum models, for which we prove the emergence of topologically protected edge states. These states are bifurcations at linear band crossings (Dirac points) of localized modes. The bifurcation is induced by the 0-energy eigenmode of a class of one-dimensional Dirac equations.
The Endemic Copepod Calanus pacificus californicus as a Potential Vector of White Spot Syndrome Virus
Authors: Mendoza-Cano Fernando , Sánchez-Paz Arturo , Terán-Díaz Berenice , Galván-Alvarez Diego , Encinas-García Trinidad , Enríquez-Espinoza Tania , Hernández-López Jorge 
Published: June 2014

Abstract
The susceptibility of the endemic copepod Calanus pacificus californicus to white spot syndrome virus (WSSV) was established by the temporal analysis of WSSV VP28 transcripts by quantitative real-time PCR (qRT-PCR). The copepods were collected from a shrimp pond located in Bahia de Kino Sonora, Mexico, and challenged per os with WSSV by a virus–phytoplankton adhesion route. Samples were collected at 0, 24, 48 and 84 h postinoculation (hpi). The VP28 transcripts were not detected at early stages (0 and 24 hpi); however, some transcript accumulation was observed at 48 hpi and gradually increased until 84 hpi. Thus, these results clearly show that the copepod C. pacificus californicus is susceptible to WSSV infection and that it may be a potential vector for the dispersal of WSSV. However, further studies are still needed to correlate the epidemiological outbreaks of WSSV with the presence of copepods in shrimp ponds.
Received May 22, 2013; accepted October 2, 2013.