Identify the Rotating Stall in Centrifugal Compressors by Fractal Dimension in Reconstructed Phase Space

Directory of Open Access Journals (Sweden)

Le Wang

2015-11-01

Full Text Available Based on phase space reconstruction and fractal dynamics in nonlinear dynamics, a method is proposed to extract and analyze the dynamics of the rotating stall in the impeller of centrifugal compressor, and some numerical examples are given to verify the results as well. First, the rotating stall of an existing low speed centrifugal compressor (LSCC is numerically simulated, and the time series of pressure in the rotating stall is obtained at various locations near the impeller outlet. Then, the phase space reconstruction is applied to these pressure time series, and a low-dimensional dynamical system, which the dynamics properties are included in, is reconstructed. In phase space reconstruction, C–C method is used to obtain the key parameters, such as time delay and the embedding dimension of the reconstructed phase space. Further, the fractal characteristics of the rotating stall are analyzed in detail, and the fractal dimensions are given for some examples to measure the complexity of the flow in the post-rotating stall. The results show that the fractal structures could reveal the intrinsic dynamics of the rotating stall flow and could be considered as a characteristic to identify the rotating stall.

Rotating stall simulation for axial and centrifugal compressors

Science.gov (United States)

Halawa, Taher; Gadala, Mohamed S.

2017-05-01

This study presents a numerical simulation of the rotating stall phenomenon in axial and centrifugal compressors with detailed descriptions of stall precursors and its development with time. Results showed that the vaneless region of the centrifugal compressor is the most critical location affected by stall. It was found that the tip leakage flow and the back flow impingement are the main cause of the stall development at the impeller exit area for centrifugal compressors. The results of the axial compressor simulations indicated that the early separated flow combined with the tip leakage flow can block the impeller passages during stall.

16 CFR 1505.50 - Stalled motor testing.

Science.gov (United States)

2010-01-01

... 16 Commercial Practices 2 2010-01-01 2010-01-01 false Stalled motor testing. 1505.50 Section 1505... USE BY CHILDREN Policies and Interpretations § 1505.50 Stalled motor testing. (a) § 1505.6(e)(4)(ii) requires that a motor-operated toy be tested with the motor stalled if the construction of the toy is such...

The Relevance of the Dynamic Stall Effect for Transient

DEFF Research Database (Denmark)

Jauch, Clemens; Sørensen, Poul; Bak-Jensen, Birgitte

2005-01-01

This article describes a methodology to quantify the influence of dynamic stall on transient fault operations of active-stall turbines. The model of the dynamic stall effect is introduced briefly. The behaviour of the dynamic stall model during a transient fault operation is described mathematica...

Biomimetic Wind Turbine Design with Lift Enhancing Periodic Stall

NARCIS (Netherlands)

Stamhuis, Eize Jan

2017-01-01

A wind turbine includes a rotor; a blade; and a periodic stall system. The periodic stall system selectively moves at least part of the blade in an oscillating motion whereby an angle of incidence continuously varies to invoke periodic stall. The periodic stall system can move the entire blade or

Close-loop Dynamic Stall Control on a Pitching Airfoil

Science.gov (United States)

Giles, Ian; Corke, Thomas

2017-11-01

A closed-loop control scheme utilizing a plasma actuator to control dynamic stall is presented. The plasma actuator is located at the leading-edge of a pitching airfoil. It initially pulses at an unsteady frequency that perturbs the boundary layer flow over the suction surface of the airfoil. As the airfoil approaches and enters stall, the amplification of the unsteady disturbance is detected by an onboard pressure sensor also located near the leading edge. Once detected, the actuator is switched to a higher voltage control state that in static airfoil experiments would reattach the flow. The threshold level of the detection is a parameter in the control scheme. Three stall regimes were examined: light, medium, and deep stall, that were defined by their stall penetration angles. The results showed that in general, the closed-loop control scheme was effective at controlling dynamic stall. The cycle-integrated lift improved in all cases, and increased by as much as 15% at the lowest stall penetration angle. As important, the cycle-integrated aerodynamic damping coefficient also increased in all cases, and was made to be positive at the light stall regime where it traditionally is negative. The latter is important in applications where negative damping can lead to stall flutter.

Stalling Tropical Cyclones over the Atlantic Basin

Science.gov (United States)

Nielsen-Gammon, J. W.; Emanuel, K.

2017-12-01

Hurricane Harvey produced massive amounts of rain over southeast Texas and southwest Louisiana. Average storm total rainfall amounts over a 10,000 square mile (26,000 square km) area exceeded 30 inches (750 mm). An important aspect of the storm that contributed to the large rainfall totals was its unusual motion. The storm stalled shortly after making landfall, then moved back offshore before once again making landfall five days later. This storm motion permitted heavy rainfall to occur in the same general area for an extended period of time. The unusual nature of this event motivates an investigation into the characteristics and potential climate change influences on stalled tropical cyclones in the Atlantic basin using the HURDAT 2 storm track database for 1866-2016 and downscaled tropical cyclones driven by simulations of present and future climate. The motion of cyclones is quantified as the size of a circle circumscribing all storm locations during a given length of time. For a three-day period, Harvey remained inside a circle with a radius of 123 km. This ranks within the top 0.6% of slowest-moving historical storm instances. Among the 2% of slowest-moving storm instances prior to Harvey, only 13 involved storms that stalled near the continental United States coast, where they may have produced substantial rainfall onshore while tapping into marine moisture. Only two such storms stalled in the month of September, in contrast to 20 September stalls out of the 36 storms that stalled over the nearby open Atlantic. Just four of the stalled coastal storms were hurricanes, implying a return frequency for such storms of much less than once per decade. The synoptic setting of these storms is examined for common features, and historical and projected trends in occurrences of stalled storms near the coast and farther offshore are investigated.

Observations of dynamic stall on Darrieus wind turbine blades

Energy Technology Data Exchange (ETDEWEB)

Fujisawa, N.; Shibuya, S. [Department of Mechanical and Production Engineering, Niigata University, 8050 Ikarashi 2, 950-2181 Niigata (Japan)

2001-02-01

Flow field around a Darrieus wind turbine blade in dynamic stall is studied by flow visualization and particle image velocimetry (PIV) measurement in stationary and rotating frames of reference. The experiment is carried out using the small-scale Darrieus wind turbine in a water tunnel. The unsteady nature of the dynamic stall observed by the flow visualization is quantitatively reproduced in the instantaneous velocity distributions by PIV measurement, which describes the successive shedding of two pairs of stall vortices from the blade moving upstream. The mechanism of dynamic stall is due to the successive generation of separation on the inner surface of the blade followed by the formation of roll-up vortices from the outer surface. Although the qualitative nature of the dynamic stall is independent of the tip-speed ratios, the blade angle for stall appearance and the growth rate of the stall vortices are influenced by the change in tip-speed ratios.

Simulation model of an active stall wind turbine controller

Energy Technology Data Exchange (ETDEWEB)

Jauch, C.; Hansen, A.D.; Soerensen, P. [Risoe National Lab., Wind Energy Dept., Rosilde (Denmark); Blaabjerg, F. [Aalborg Univ., Inst. of Energy Technology (Denmark)

2004-07-01

This paper describes an active stall wind turbine controller. The objective is to develop a general model of an active stall controller in order to simulate the operation of grid connected active stall wind turbines. The active stall turbine concept and its control strategies are presented and evaluated on the basis of simulations. The presented controller is described for continuous operation under all wind speeds from start-up wind speed to shut doven wind speed. Due to its parametric implementation it is general i.e. it can represent different active stall wind turbine controllers and can be implemented in different simulation tools. (au)

Alleviation of spike stall in axial compressors utilizing grooved casing treatment

Directory of Open Access Journals (Sweden)

Reza Taghavi-Zenouz

2015-06-01

Full Text Available This article deals with application of grooved type casing treatment for suppression of spike stall in an isolated axial compressor rotor blade row. The continuous grooved casing treatment covering the whole compressor circumference is of 1.8 mm in depth and located between 90% and 108% chord of the blade tip as measured from leading edge. The method of investigation is based on time-accurate three-dimensional full annulus numerical simulations for cases with and without casing treatment. Discretization of the Navier–Stokes equations has been carried out based on an upwind second-order scheme and k-ω-SST (Shear Stress Transport turbulence modeling has been used for estimation of eddy viscosity. Time-dependent flow structure results for the smooth casing reveal that there are two criteria for spike stall inception known as leading edge spillage and trailing edge backflow, which occur at specific mass flow rates in near-stall conditions. In this case, two dominant stall cells of different sizes could be observed. The larger one is caused by the spike stall covering roughly two blade passages in the circumferential direction and about 25% span in the radial direction. Spike stall disturbances are accompanied by lower frequencies and higher amplitudes of the pressure signals. Casing treatment causes flow blockages to reduce due to alleviation of backflow regions, which in turn reduces the total pressure loss and increases the axial velocity in the blade tip gap region, as well as tip leakage flow fluctuation at higher frequencies and lower amplitudes. Eventually, it can be concluded that the casing treatment of the stepped tip gap type could increase the stall margin of the compressor. This fact is basically due to retarding the movement of the interface region between incoming and tip leakage flows towards the rotor leading edge plane and suppressing the reversed flow around the blade trailing edge.

Comparison of driven and simulated "free" stall flutter in a wind tunnel

Science.gov (United States)

Culler, Ethan; Farnsworth, John; Fagley, Casey; Seidel, Jurgen

2016-11-01

Stall flutter and dynamic stall have received a significant amount of attention over the years. To experimentally study this problem, the body undergoing stall flutter is typically driven at a characteristic, single frequency sinusoid with a prescribed pitching amplitude and mean angle of attack offset. This approach allows for testing with repeatable kinematics, however it effectively decouples the structural motion from the aerodynamic forcing. Recent results suggest that this driven approach could misrepresent the forcing observed in a "free" stall flutter scenario. Specifically, a dynamically pitched rigid NACA 0018 wing section was tested in the wind tunnel under two modes of operation: (1) Cyber-Physical where "free" stall flutter was physically simulated through a custom motor-control system modeling a torsional spring and (2) Direct Motor-Driven Dynamic Pitch at a single frequency sinusoid representative of the cyber-physical motion. The time-resolved pitch angle and moment were directly measured and compared for each case. It was found that small deviations in the pitch angle trajectory between these two operational cases generate significantly different aerodynamic pitching moments on the wing section, with the pitching moments nearly 180o out of phase in some cases. This work is supported by the Air Force Office of Scientific Research through the Flow Interactions and Control Program and by the National Defense Science and Engineering Graduate Fellowship Program.

A numerical strategy for modelling rotating stall in core compressors

Science.gov (United States)

Vahdati, M.

2007-03-01

The paper will focus on one specific core-compressor instability, rotating stall, because of the pressing industrial need to improve current design methods. The determination of the blade response during rotating stall is a difficult problem for which there is no reliable procedure. During rotating stall, the blades encounter the stall cells and the excitation depends on the number, size, exact shape and rotational speed of these cells. The long-term aim is to minimize the forced response due to rotating stall excitation by avoiding potential matches between the vibration modes and the rotating stall pattern characteristics. Accurate numerical simulations of core-compressor rotating stall phenomena require the modelling of a large number of bladerows using grids containing several tens of millions of points. The time-accurate unsteady-flow computations may need to be run for several engine revolutions for rotating stall to get initiated and many more before it is fully developed. The difficulty in rotating stall initiation arises from a lack of representation of the triggering disturbances which are inherently present in aeroengines. Since the numerical model represents a symmetric assembly, the only random mechanism for rotating stall initiation is provided by numerical round-off errors. In this work, rotating stall is initiated by introducing a small amount of geometric mistuning to the rotor blades. Another major obstacle in modelling flows near stall is the specification of appropriate upstream and downstream boundary conditions. Obtaining reliable boundary conditions for such flows can be very difficult. In the present study, the low-pressure compression (LPC) domain is placed upstream of the core compressor. With such an approach, only far field atmospheric boundary conditions are specified which are obtained from aircraft speed and altitude. A chocked variable-area nozzle, placed after the last compressor bladerow in the model, is used to impose boundary

Dynamic Stall Characteristics of Drooped Leading Edge Airfoils

Science.gov (United States)

Sankar, Lakshmi N.; Sahin, Mehmet; Gopal, Naveen

2000-01-01

Helicopters in high-speed forward flight usually experience large regions of dynamic stall over the retreating side of the rotor disk. The rapid variations in the lift and pitching moments associated with the stall process can result in vibratory loads, and can cause fatigue and failure of pitch links. In some instances, the large time lag between the aerodynamic forces and the blade motion can trigger stall flutter. A number of techniques for the alleviation of dynamic stall have been proposed and studied by researchers. Passive and active control techniques have both been explored. Passive techniques include the use of high solidity rotors that reduce the lift coefficients of individual blades, leading edge slots and leading edge slats. Active control techniques include steady and unsteady blowing, and dynamically deformable leading edge (DDLE) airfoils. Considerable amount of experimental and numerical data has been collected on the effectiveness of these concepts. One concept that has not received as much attention is the drooped-leading edge airfoil idea. It has been observed in wind tunnel studies and flight tests that drooped leading edge airfoils can have a milder dynamic stall, with a significantly milder load hysteresis. Drooped leading edge airfoils may not, however, be suitable at other conditions, e.g. in hover, or in transonic flow. Work needs to be done on the analysis and design of drooped leading edge airfoils for efficient operation in a variety of flight regimes (hover, dynamic stall, and transonic flow). One concept that is worthy of investigation is the dynamically drooping airfoil, where the leading edge shape is changed roughly once-per-rev to mitigate the dynamic stall.

Prediction of induced vibrations in stall

Energy Technology Data Exchange (ETDEWEB)

Thirstrup Petersen, J; Thomsen, K; Aagaard Madsen, H [Risoe National Lab., Wind Energy and Atmospheric Physics Dept., Roskilde (Denmark)

1999-03-01

The main results from recent research in stall induced vibrations are presented. The focus is on the edgewise blade vibrations, which during the last decade have turned out to be a potential threat against the stable operation of stall regulated wind turbines and a fact, which must be dealt with by the designer. The basic physical explanation for the phenomenon and examples of design precaution, which can be taken, are presented. (au)

Flow and Noise Characteristics of Centrifugal Fan under Different Stall Conditions

Directory of Open Access Journals (Sweden)

Lei Zhang

2014-01-01

Full Text Available An implicit, time-accurate 3D Reynolds-averaged Navier-Stokes (RANS solver is used to simulate the rotating stall phenomenon in a centrifugal fan. The goal of the present work is to shed light on the flow field and particularly the aerodynamic noise at different stall conditions. Aerodynamic characteristics, frequency domain characteristics, and the contours of sound power level under two different stall conditions are discussed in this paper. The results show that, with the decrease of valve opening, the amplitude of full pressure and flow fluctuations tends to be larger and the stall frequency remains the same. The flow field analysis indicates that the area occupied by stall cells expands with the decrease of flow rate. The noise calculation based on the simulation underlines the role of vortex noise after the occurrence of rotating stall, showing that the high noise area rotates along with the stall cell in the circumferential direction.

Simulation of Entropy Generation under Stall Conditions in a Centrifugal Fan

Directory of Open Access Journals (Sweden)

Lei Zhang

2014-06-01

Full Text Available Rotating stalls are generally the first instability met in turbomachinery, before surges. This 3D phenomenon is characterized by one or more stalled flow cells which rotate at a fraction of the impeller speed. The goal of the present work is to shed some light on the entropy generation in a centrifugal fan under rotating stall conditions. A numerical simulation of entropy generation is carried out with the ANSYS Fluent software which solves the Navier-Stokes equations and user defined function (UDF. The entropy generation characteristics in the centrifugal fan for five typical conditions are presented and discussed, involving the design condition, conditions on occurrence and development of stall inception, the rotating stall conditions with two throttle coefficients. The results show that the entropy generation increases after the occurrence of stall inception. The high entropy generation areas move along the circumferential and axial directions, and finally merge into one stall cell. The entropy generation rate during circumferential propagation of the stall cell is also discussed, showing that the entropy generation history is similar to sine curves in impeller and volute, and the volute tongue has a great influence on entropy generation in the centrifugal fan.

Economic evaluation of stall stocking density of lactating dairy cows

NARCIS (Netherlands)

Vries, De Albert; Dechassa, Hailegziabher; Hogeveen, Henk

2016-01-01

An increase in stall stocking density (SSD), as measured by the number of lactating cows per stall in a freestall barn, reduces cow performance, such as milk yield and fertility, but may increase farm profitability. Our objectives were to calculate effects of varying SSD on profit per stall for a

Simulation model of an active-stall fixed-speed wind turbine controller

Energy Technology Data Exchange (ETDEWEB)

Jauch, C.; Hansen, A.D.; Sorensen, P.; Blaabjerg, F.

2004-07-01

This paper describes an active-stall wind turbine controller. The objective is to develop a general model of an active stall controller in order to simulate the operation of grid connected active stall wind turbines. The active stall turbine concept and its control strategies are presented and evaluated by simulations. The presented controller is described for continuous operation under all wind speeds from start-up wind speed to shut down wind speed. Due to its parametric implementation it is general i. e. it can represent different active stall wind turbine controllers and can be implemented in different simulation tools. (author)

A CFD Database for Airfoils and Wings at Post-Stall Angles of Attack

Science.gov (United States)

Petrilli, Justin; Paul, Ryan; Gopalarathnam, Ashok; Frink, Neal T.

2013-01-01

This paper presents selected results from an ongoing effort to develop an aerodynamic database from Reynolds-Averaged Navier-Stokes (RANS) computational analysis of airfoils and wings at stall and post-stall angles of attack. The data obtained from this effort will be used for validation and refinement of a low-order post-stall prediction method developed at NCSU, and to fill existing gaps in high angle of attack data in the literature. Such data could have potential applications in post-stall flight dynamics, helicopter aerodynamics and wind turbine aerodynamics. An overview of the NASA TetrUSS CFD package used for the RANS computational approach is presented. Detailed results for three airfoils are presented to compare their stall and post-stall behavior. The results for finite wings at stall and post-stall conditions focus on the effects of taper-ratio and sweep angle, with particular attention to whether the sectional flows can be approximated using two-dimensional flow over a stalled airfoil. While this approximation seems reasonable for unswept wings even at post-stall conditions, significant spanwise flow on stalled swept wings preclude the use of two-dimensional data to model sectional flows on swept wings. Thus, further effort is needed in low-order aerodynamic modeling of swept wings at stalled conditions.

Wider stall space affects behavior, lesion scores, and productivity of gestating sows.

Science.gov (United States)

Salak-Johnson, J L; DeDecker, A E; Levitin, H A; McGarry, B M

2015-10-01

Limited space allowance within the standard gestation stall is an important welfare concern because it restricts the ability of the sow to make postural adjustments and hinders her ability to perform natural behaviors. Therefore, we evaluated the impacts of increasing stall space and/or providing sows the freedom to access a small pen area on sow well-being using multiple welfare metrics. A total of 96 primi- and multiparous crossbred sows were randomly assigned in groups of 4 sows/treatment across 8 replicates to 1 of 3 stall treatments (TRT): standard stall (CTL; dimensions: 61 by 216 cm), width-adjustable stall (flex stall [FLX]; dimensions: adjustable width of 56 to 79 cm by 216 cm), or an individual walk-in/lock-in stall with access to a small communal open-pen area at the rear of the stall (free-access stall [FAS]; dimensions: 69 by 226 cm). Lesion scores, behavior, and immune and productivity traits were measured at various gestational days throughout the study. Total lesion scores were greatest for sows in FAS and least for sows in FLX ( pregnancy progressed, lesion scores increased among sows in CTL ( postural behaviors and sham chew behavior were affected by TRT ( changes in postural behaviors, lesion severity scores, and other sow traits. Moreover, compromised welfare measures found among sows in various stall environments may be partly attributed to the specific constraints of each stall system such as restricted stall space in CTL, insufficient floor space in the open-pen area of the FAS system, and gate design of the FLX (e.g., direction of bars and feeder space). These results also indicate that parity and gestational day are additional factors that may exacerbate the effects of restricted stall space or insufficient pen space, further compromising sow well-being.

Conducting Classroom Observations : Stallings 'Classroom Snapshot' Observation System for an Electronic Tablet

OpenAIRE

World Bank Group

2017-01-01

The “Stallings Classroom Snapshot” instrument, technically called the “Stanford Research Institute Classroom Observation System”, was developed by Professor Jane Stallings for research on the efficiency and quality of basic education teachers in the United States in the 1970s. (Stallings, 1977; Stallings and Mohlman, 1988). The Stallings instrument generates robust quantitative data on the interaction of teachers and students in the classroom, with a high degree of inter-rater rel...

Inception mechanism and suppression of rotating stall in an axial-flow fan

International Nuclear Information System (INIS)

Nishioka, T

2013-01-01

Inception patterns of rotating stall at two stagger-angle settings for the highly loaded rotor blades were experimentally investigated in a low-speed axial-flow fan. Rotor-tip flow fields were also numerically investigated to clarify the mechanism behind the rotating stall inception. The stall inception patterns depended on the rotor stagger-angle settings. The stall inception from a rotating instability was confirmed at the design stagger-angle settings. The stall inception from a short length-scale stall cell (spike) was also confirmed at the small stagger-angle setting. The spillage of tip-leakage flow and the tip-leakage vortex breakdown influence the rotating stall inception. An air-separator has been developed based on the clarified inception mechanism of rotating stall. The rotating stall was suppressed by the developed air-separator, and the operating range of fan was extended towards low flow rate. The effect of developed air-separator was also confirmed by application to a primary air fan used in a coal fired power plant. It is concluded from these results that the developed air-separator can provide a wide operating range for an axial-flow fan

Monitoring indices of cow comfort in free-stall-housed dairy herds.

Science.gov (United States)

Cook, N B; Bennett, T B; Nordlund, K V

2005-11-01

Indices of cow comfort are used widely by consultants in the dairy industry, with a general understanding that they are representative of lying behavior. This study examines the influence of stall base type (sand or a geotextile mattress filled with rubber crumbs) and time of measurement on 4 indices of comfort collected at hourly intervals in 12 herds, aligned by morning and afternoon milking. Stall base type significantly influenced all indices of comfort. For example, the least squares mean (SE) cow comfort index (proportion of cows touching a stall that are lying down) was 0.76 (0.015) in herds with mattresses compared with 0.86 (0.015) in herds with sand stalls. Significant hourly variation was also identified suggesting that timing of measurement is important. None of the indices of cow comfort derived from the high-yielding group pen was associated with the mean 24-h lying time of 10 sentinel cows whose time budgets were known in each herd. However, the cow comfort index was associated with the herd mean 24-h stall standing time, with the strongest relationships occurring 2 h before the morning and afternoon milking, when stall base type did not significantly influence the association. When measured at these times, we recommend use of the stall standing index (proportion of cows touching a stall that are standing), with values greater than 0.20 being associated with abnormally long herd mean stall standing times greater than 2 h/d.

14 CFR 33.65 - Surge and stall characteristics.

Science.gov (United States)

2010-01-01

... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Surge and stall characteristics. 33.65 Section 33.65 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION AIRCRAFT... stall characteristics. When the engine is operated in accordance with operating instructions required by...

Dairy Cows Produce Less Milk and Modify Their Behaviour during the Transition between Tie-Stall to Free-Stall

Science.gov (United States)

Broucek, Jan; Uhrincat, Michal; Mihina, Stefan; Soch, Miloslav; Mrekajova, Andrea; Hanus, Anton

2017-01-01

Simple Summary The purpose of this study was to evaluate the influence of moving cows from the barn with stanchion-stall housing to free-stall housing on their behaviour and production. Cows lay down up to ten hours after removing. The cows in their second lactation and open cows tended to lie sooner after removing than cows in their first lactation and pregnant cows. The times of total lying and rumination were increasing from the first day to the tenth day after removing. Cows produced 23.3% less milk at the first day following the transfer than at the last day prior to moving (23.76 ± 7.20 kg vs. 30.97 ± 7.26 kg, p cows achieved maximum production. The difference was found in milk losses due to the shift between cows in first and second lactation. Abstract Transfer of cattle to an unknown barn may result in a reduction in its welfare. Housing and management practices can result in signs of stress that include a long-term suppression of milk efficiency. The purpose of this study was to evaluate the influence of moving cows from the stanchion-stall housing to free-stall housing on their behaviour and production. The Holstein cows were moved into the new facility with free-stall housing from the old barn with stanchion-stall housing. Cows lay down up to ten hours (596.3 ± 282.7 min) after removing. The cows in their second lactation and open cows tended to lie sooner after removing than cows in their first lactation and pregnant cows. The times of total lying and rumination were increasing from the first day to the tenth day after removing (23.76 ± 7.20 kg vs. 30.97 ± 7.26 kg, p Cows produced 23.3% less milk at the first day following the transfer than at the last day prior to moving (p cows on the first and second lactation (p cows’ milk production. However, when the cows are moved to a better environment, they rapidly adapt to the change. PMID:28273810

Dynamic stall and 3D effects

Energy Technology Data Exchange (ETDEWEB)

Bjoerck, A.; Thor, S.E. [Aeronautical Research Inst. of Sweden, Bromma (Sweden)

1996-12-01

The JOULE II project `Dynamic stall and 3D effects` started in January 1994 and was completed in September 1995. The objective of the project has been to increase the understanding of the three-dimensional and unsteady aerodynamics of stall controlled HAWT`s. The objectives have also been to develop `engineering models` suitable for inclusion into aero-elastic codes. The project included the participation of 13 parties within Europe. This paper describes an overview of the work carried out within the project and key results. 3 refs, 4 figs

Both DNA Polymerases δ and ε Contact Active and Stalled Replication Forks Differently

Science.gov (United States)

Yu, Chuanhe; Gan, Haiyun

2017-01-01

ABSTRACT Three DNA polymerases, polymerases α, δ, and ε (Pol α, Pol δ, and Pol ε), are responsible for eukaryotic genome duplication. When DNA replication stress is encountered, DNA synthesis stalls until the stress is ameliorated. However, it is not known whether there is a difference in the association of each polymerase with active and stalled replication forks. Here, we show that each DNA polymerase has a distinct pattern of association with active and stalled replication forks. Pol α is enriched at extending Okazaki fragments of active and stalled forks. In contrast, although Pol δ contacts the nascent lagging strands of active and stalled forks, it binds to only the matured (and not elongating) Okazaki fragments of stalled forks. Pol ε has greater contact with the nascent single-stranded DNA (ssDNA) of the leading strand on active forks than on stalled forks. We propose that the configuration of DNA polymerases at stalled forks facilitates the resumption of DNA synthesis after stress removal. PMID:28784720

Airfoil stall interpreted through linear stability analysis

Science.gov (United States)

Busquet, Denis; Juniper, Matthew; Richez, Francois; Marquet, Olivier; Sipp, Denis

2017-11-01

Although airfoil stall has been widely investigated, the origin of this phenomenon, which manifests as a sudden drop of lift, is still not clearly understood. In the specific case of static stall, multiple steady solutions have been identified experimentally and numerically around the stall angle. We are interested here in investigating the stability of these steady solutions so as to first model and then control the dynamics. The study is performed on a 2D helicopter blade airfoil OA209 at low Mach number, M 0.2 and high Reynolds number, Re 1.8 ×106 . Steady RANS computation using a Spalart-Allmaras model is coupled with continuation methods (pseudo-arclength and Newton's method) to obtain steady states for several angles of incidence. The results show one upper branch (high lift), one lower branch (low lift) connected by a middle branch, characterizing an hysteresis phenomenon. A linear stability analysis performed around these equilibrium states highlights a mode responsible for stall, which starts with a low frequency oscillation. A bifurcation scenario is deduced from the behaviour of this mode. To shed light on the nonlinear behavior, a low order nonlinear model is created with the same linear stability behavior as that observed for that airfoil.

A comparison of free-stall barns used by modernized Wisconsin dairies.

Science.gov (United States)

Bewley, J; Palmer, R W; Jackson-Smith, D B

2001-02-01

A primary objective of the Wisconsin Dairy Modernization Survey was to compare features of free-stall barns available to dairy producers. This study used data from a large random sample of expanding dairy farms to determine whether the theoretical benefits of particular free-stall configurations bear out under on-farm conditions. Comparisons were made among herds using free-stall barns as their primary housing for new versus remodeled facilities, barn design, bedding used, feed-delivery design, manure removal strategies, animal restraint, maternity areas, overcrowding, and cooling methods. Producers who made the transition from tie-stall housing to free-stall housing were satisfied with this decision. New free-stall barns provided a more desirable environment for the herds than remodeled free-stall barns, although initial investments were higher. When new free-stall barns were compared, herds with four-row barns had higher production, lower somatic cell count, and higher stocking rates than herds with six-row barns. Respondents were more satisfied with four- and six-row barns than with two- and three-row barns. Respondents felt sand provided some advantages for cow comfort, while satisfaction with bedding cost and manure handling was higher with mattresses. Dairy Herd Improvement data showed no difference in milk production or somatic cell count for producers who chose sand or mattress-based free stalls. Respondents were more satisfied with the use of drive-through feeding than other feed-delivery designs. Most producers chose to use tractor scrapers to remove manure; however, producers who used automated systems were more satisfied with manure management. Few differences were observed when comparing self-locking head gates to palpation rails. Overcrowding did not have any adverse affect on production or user satisfaction with feed intake or cow comfort. Using supplemental cooling appeared to facilitate higher production.

Associations between cow hygiene, hock injuries, and free stall usage on US dairy farms.

Science.gov (United States)

Lombard, J E; Tucker, C B; von Keyserlingk, M A G; Kopral, C A; Weary, D M

2010-10-01

This cross-sectional study evaluated cow comfort measures in free stall dairies across the United States as part of the National Animal Health Monitoring System's Dairy 2007 study. The study was conducted in 17 states and evaluations were completed between March 5 and September 5, 2007. Assessors recorded hygiene and hock scores, number of cows housed in the pen, the number of cows standing with only the front feet in a stall, standing fully in a stall, and lying in a stall. Facility design measures included bedding type, bedding quantity, stall length and width, presence of a neck rail or brisket locator, and relevant distances from the rear and bed of the stall. Of the 491 operations that completed the cow comfort assessment, 297 had Holstein cows housed in free stalls and were included in this analysis. Negative binomial models were constructed to evaluate the following outcomes: the number of cows that were very dirty, had severe hock injuries, stood with front feet in the stall, stood with all feet in the stall, and were lying in the stall. Hygiene was better on farms that did not tail dock cows compared with those that did (5.7 vs. 8.8% were dirty) and on farms located in the study's west region compared with those located in the east region (5.2 vs. 9.7% were dirty). Severe hock injuries were less common on farms in the west than those in the east (0.5 vs. 4.1%). In addition, severe hock injuries were less common on farms that used dirt as a stall base or sand as bedding compared with farms that did not. A higher percentage of cows was standing with front feet in the stall at higher ambient temperatures (incidence rate ratio=1.016) and as time since feeding increased (incidence rate ratio=1.030). A lower percentage of cows were standing with front feet in the stall when the stalls were shorter and when there were fewer cows per stall. Standing fully in a stall was performed by a higher percentage of cows during the summer than during the spring (13.6 vs. 8

Identification of phlebovirus and arenavirus RNA sequences that stall and repress the exoribonuclease XRN1.

Science.gov (United States)

Charley, Phillida A; Wilusz, Carol J; Wilusz, Jeffrey

2018-01-05

Regulated mRNA decay plays a vital role in determining both the level and quality of cellular gene expression. Viral RNAs must successfully evade this host RNA decay machinery to establish a productive infection. One way for RNA viruses to accomplish this is to target the cellular exoribonuclease XRN1, because this enzyme is accessible in the cytoplasm and plays a major role in mRNA decay. Members of the Flaviviridae use RNA structures in their 5'- or 3'-untranslated regions to stall and repress XRN1, effectively stabilizing viral RNAs while also causing significant dysregulation of host cell mRNA stability. Here, we use a series of biochemical assays to demonstrate that the 3'-terminal portion of the nucleocapsid (N) mRNA of Rift Valley fever virus, a phlebovirus of the Bunyaviridae family, also can effectively stall and repress XRN1. The region responsible for impeding XRN1 includes a G-rich portion that likely forms a G-quadruplex structure. The 3'-terminal portions of ambisense-derived transcripts of multiple arenaviruses also stalled XRN1. Therefore, we conclude that RNAs from two additional families of mammalian RNA viruses stall and repress XRN1. This observation. emphasizes the importance and commonality of this viral strategy to interfere with the 5'-to-3'-exoribonuclease component of the cytoplasmic RNA decay machinery. © 2018 by The American Society for Biochemistry and Molecular Biology, Inc.

A Comparative Study of Three Methodologies for Modeling Dynamic Stall

Science.gov (United States)

Sankar, L.; Rhee, M.; Tung, C.; ZibiBailly, J.; LeBalleur, J. C.; Blaise, D.; Rouzaud, O.

2002-01-01

During the past two decades, there has been an increased reliance on the use of computational fluid dynamics methods for modeling rotors in high speed forward flight. Computational methods are being developed for modeling the shock induced loads on the advancing side, first-principles based modeling of the trailing wake evolution, and for retreating blade stall. The retreating blade dynamic stall problem has received particular attention, because the large variations in lift and pitching moments encountered in dynamic stall can lead to blade vibrations and pitch link fatigue. Restricting to aerodynamics, the numerical prediction of dynamic stall is still a complex and challenging CFD problem, that, even in two dimensions at low speed, gathers the major difficulties of aerodynamics, such as the grid resolution requirements for the viscous phenomena at leading-edge bubbles or in mixing-layers, the bias of the numerical viscosity, and the major difficulties of the physical modeling, such as the turbulence models, the transition models, whose both determinant influences, already present in static maximal-lift or stall computations, are emphasized by the dynamic aspect of the phenomena.

Effect of summer grazing on welfare of dairy cows reared in mountain tie-stall barns

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Simonetta Dovier

2010-09-01

Full Text Available Traditional mountain farms have an important economic, social and environmental role. The Alps management system for dairy cows consists of animals kept indoors from autumn to spring, mostly in tie-stalls, and moved to mountain pasture in summer. The aim of our study was to assess the effect of mountain summer grazing on the welfare of dairy cows housed in tie-stall barns. Twenty-four farms were considered. In twelve of them, animals were reared in tie-stalls and moved to mountain pasture for three months in summer; they were visited three times: (i four weeks before grazing during the indoor period in the stall; (ii about three weeks after the start of grazing; and (iii in the stall, in autumn, at least three weeks after returning from grazing. The other twelve farms kept the animals in tie-stalls all year; they were visited once in autumn. Data were collected following a protocol that considers animal-based measures and structure information on the basis of Quality Welfare Consortium® indications. Data allowed the calculation of both the Animal Needs Index score (ANI 35L and an overall assessment of the cows’ welfare obtained from three general aspects: housing, animal’s physical condition, and animal’s behaviour. Summer grazing had a significant positive effect on injuries, lameness and animal’s rising duration but a negative effect on faeces consistency. Moreover, a reduction of tongue playing was observed. The ANI 35L and the overall assessment did not show significant differences linked to summer grazing, which tended to have a positive but temporary effect on animal behaviour.

Precautions against axial fan stall in reactor building to Tianwan NPP

International Nuclear Information System (INIS)

Liu Chunlong; Pei Junmin

2011-01-01

The paper introduces the mechanism and harm of rotating stall of axial fans, analyzes the necessity for prevention against axial fan stall in reactor building of Tianwan NPP, introduces the precautions, and then makes an assessment on anti-stall effect of flow separators. It can provide reference for model-selection or reconstruction of similar fans in power stations, and for operation and maintenance of axial fans. (authors)

Simulation of Broadband Noise Sources of an Axial Fan under Rotating Stall Conditions

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Lei Zhang

2014-11-01

Full Text Available Study on the influence of rotating stall on the aerodynamic noise of axial fan has important value to warn of the occurrence of stall through monitoring the noise variations. The present work is to analyze the aerodynamic noise before and after the phenomenon of rotating stall by solving Navier-Stokes equations, coupled with the throttle condition and the broadband noise sources model. The impeller exit rotational Mach number and rotational Reynolds number are separately 0.407 and 8.332 × 106. The results show that the aerodynamic noise source of the fan is mainly the rotation noise under the design condition. The vortex noise accounts for the major part of fan noise after the occurrence of stall, and the maximum acoustic power level of the fan appears in the rotor domains. In the evolution process from the stall inception to the stall cell, the high noise regions of the rotor develop along the radial, circumferential, and axial directions, and the area occupied by high noise regions increases from 33% to 46% impeller channels area. On rotating stall condition, the high noise regions occupying about 46% impeller channels area propagate with the stall cell along the circumferential direction at a half of rotor speed.

Checkpoint responses to replication stalling: inducing tolerance and preventing mutagenesis

Energy Technology Data Exchange (ETDEWEB)

Kai, Mihoko; Wang, Teresa S.-F

2003-11-27

Replication mutants often exhibit a mutator phenotype characterized by point mutations, single base frameshifts, and the deletion or duplication of sequences flanked by homologous repeats. Mutation in genes encoding checkpoint proteins can significantly affect the mutator phenotype. Here, we use fission yeast (Schizosaccharomyces pombe) as a model system to discuss the checkpoint responses to replication perturbations induced by replication mutants. Checkpoint activation induced by a DNA polymerase mutant, aside from delay of mitotic entry, up-regulates the translesion polymerase DinB (Pol{kappa}). Checkpoint Rad9-Rad1-Hus1 (9-1-1) complex, which is loaded onto chromatin by the Rad17-Rfc2-5 checkpoint complex in response to replication perturbation, recruits DinB onto chromatin to generate the point mutations and single nucleotide frameshifts in the replication mutator. This chain of events reveals a novel checkpoint-induced tolerance mechanism that allows cells to cope with replication perturbation, presumably to make possible restarting stalled replication forks. Fission yeast Cds1 kinase plays an essential role in maintaining DNA replication fork stability in the face of DNA damage and replication fork stalling. Cds1 kinase is known to regulate three proteins that are implicated in maintaining replication fork stability: Mus81-Eme1, a hetero-dimeric structure-specific endonuclease complex; Rqh1, a RecQ-family helicase involved in suppressing inappropriate recombination during replication; and Rad60, a protein required for recombinational repair during replication. These Cds1-regulated proteins are thought to cooperatively prevent mutagenesis and maintain replication fork stability in cells under replication stress. These checkpoint-regulated processes allow cells to survive replication perturbation by preventing stalled replication forks from degenerating into deleterious DNA structures resulting in genomic instability and cancer development.

Checkpoint responses to replication stalling: inducing tolerance and preventing mutagenesis

International Nuclear Information System (INIS)

Kai, Mihoko; Wang, Teresa S.-F.

2003-01-01

Replication mutants often exhibit a mutator phenotype characterized by point mutations, single base frameshifts, and the deletion or duplication of sequences flanked by homologous repeats. Mutation in genes encoding checkpoint proteins can significantly affect the mutator phenotype. Here, we use fission yeast (Schizosaccharomyces pombe) as a model system to discuss the checkpoint responses to replication perturbations induced by replication mutants. Checkpoint activation induced by a DNA polymerase mutant, aside from delay of mitotic entry, up-regulates the translesion polymerase DinB (Polκ). Checkpoint Rad9-Rad1-Hus1 (9-1-1) complex, which is loaded onto chromatin by the Rad17-Rfc2-5 checkpoint complex in response to replication perturbation, recruits DinB onto chromatin to generate the point mutations and single nucleotide frameshifts in the replication mutator. This chain of events reveals a novel checkpoint-induced tolerance mechanism that allows cells to cope with replication perturbation, presumably to make possible restarting stalled replication forks. Fission yeast Cds1 kinase plays an essential role in maintaining DNA replication fork stability in the face of DNA damage and replication fork stalling. Cds1 kinase is known to regulate three proteins that are implicated in maintaining replication fork stability: Mus81-Eme1, a hetero-dimeric structure-specific endonuclease complex; Rqh1, a RecQ-family helicase involved in suppressing inappropriate recombination during replication; and Rad60, a protein required for recombinational repair during replication. These Cds1-regulated proteins are thought to cooperatively prevent mutagenesis and maintain replication fork stability in cells under replication stress. These checkpoint-regulated processes allow cells to survive replication perturbation by preventing stalled replication forks from degenerating into deleterious DNA structures resulting in genomic instability and cancer development

Preferences of dairy cows for three stall surface materials with small amounts of bedding.

Science.gov (United States)

Norring, M; Manninen, E; de Passillé, A M; Rushen, J; Saloniemi, H

2010-01-01

Farmers' concerns about the economy, cost of labor, and hygiene have resulted in reduced use of organic bedding in stalls for dairy cows; however, the reduced use of organic bedding possibly impairs cow comfort. The effects of different stall surface materials were evaluated in an unheated building in which only a small amount of bedding was used. The lying time and preferences of 18 cows using 3 stall surface materials (concrete, soft rubber mat, and sand) were compared. All materials were lightly bedded with a small amount of straw, and the amount of straw added to each stall was measured. The cows only had access to stalls of one surface type while their lying time was observed. Lying times were longest on the rubber mats compared with other surfaces (rubber mat 768; concrete 727; sand 707+/-16 min/d). In a preference test, cows had access to 2 of the 3 types of stalls for 10 d and their stall preference was measured. Cows preferred stalls with rubber mats to stalls with a concrete floor (median 73 vs. 18 from a total of 160 observations per day; interquartile range was 27 and 12, respectively), but showed no preference for sand stalls compared with stalls with a concrete floor or with rubber mats. More straw was needed on sand stalls compared with concrete or mat (638+/-13 g/d on sand, 468+/-10 g/d on concrete, and 464+/-8 g/d on rubber mats). Lying times on bedded mats indicated that mats were comfortable for the cows. If availability or cost of bedding material requires limiting the amount of bedding used, rubber mats may help maintain cow comfort. Copyright 2010 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

Does facial resemblance enhance cooperation?

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Trang Giang

Full Text Available Facial self-resemblance has been proposed to serve as a kinship cue that facilitates cooperation between kin. In the present study, facial resemblance was manipulated by morphing stimulus faces with the participants' own faces or control faces (resulting in self-resemblant or other-resemblant composite faces. A norming study showed that the perceived degree of kinship was higher for the participants and the self-resemblant composite faces than for actual first-degree relatives. Effects of facial self-resemblance on trust and cooperation were tested in a paradigm that has proven to be sensitive to facial trustworthiness, facial likability, and facial expression. First, participants played a cooperation game in which the composite faces were shown. Then, likability ratings were assessed. In a source memory test, participants were required to identify old and new faces, and were asked to remember whether the faces belonged to cooperators or cheaters in the cooperation game. Old-new recognition was enhanced for self-resemblant faces in comparison to other-resemblant faces. However, facial self-resemblance had no effects on the degree of cooperation in the cooperation game, on the emotional evaluation of the faces as reflected in the likability judgments, and on the expectation that a face belonged to a cooperator rather than to a cheater. Therefore, the present results are clearly inconsistent with the assumption of an evolved kin recognition module built into the human face recognition system.

Bacillus cereus in free-stall bedding.

Science.gov (United States)

Magnusson, M; Svensson, B; Kolstrup, C; Christiansson, A

2007-12-01

To increase the understanding of how different factors affect the bacterial growth in deep sawdust beds for dairy cattle, the microbiological status of Bacillus cereus and coliforms in deep sawdust-bedded free stalls was investigated over two 14-d periods on one farm. High counts of B. cereus and coliforms were found in the entire beds. On average, 4.1 log(10) B. cereus spores, 5.5 log(10) B. cereus, and 6.7 log(10) coliforms per gram of bedding could be found in the upper layers of the sawdust likely to be in contact with the cows' udders. The highest counts of B. cereus spores, B. cereus, and coliforms were found in the bedding before fresh bedding was added, and the lowest immediately afterwards. Different factors of importance for the growth of B. cereus in the bedding material were explored in laboratory tests. These were found to be the type of bedding, pH, and the type and availability of nutrients. Alternative bedding material such as peat and mixtures of peat and sawdust inhibited the bacterial growth of B. cereus. The extent of growth of B. cereus in the sawdust was increased in a dose-dependent manner by the availability of feces. Urine added to different bedding material raised the pH and also led to bacterial growth of B. cereus in the peat. In sawdust, a dry matter content greater than 70% was needed to lower the water activity to 0.95, which is needed to inhibit the growth of B. cereus. In an attempt to reduce the bacterial growth of B. cereus and coliforms in deep sawdust beds on the farm, the effect of giving bedding daily or a full replacement of the beds was studied. The spore count of B. cereus in the back part of the free stalls before fresh bedding was added was 0.9 log units lower in stalls given daily bedding than in stalls given bedding twice weekly. No effect on coliform counts was found. Replacement of the entire sawdust bedding had an effect for a short period, but by 1 to 2 mo after replacement, the counts of B. cereus spores in the

Stall Recovery Guidance Algorithms Based on Constrained Control Approaches

Science.gov (United States)

Stepanyan, Vahram; Krishnakumar, Kalmanje; Kaneshige, John; Acosta, Diana

2016-01-01

Aircraft loss-of-control, in particular approach to stall or fully developed stall, is a major factor contributing to aircraft safety risks, which emphasizes the need to develop algorithms that are capable of assisting the pilots to identify the problem and providing guidance to recover the aircraft. In this paper we present several stall recovery guidance algorithms, which are implemented in the background without interfering with flight control system and altering the pilot's actions. They are using input and state constrained control methods to generate guidance signals, which are provided to the pilot in the form of visual cues. It is the pilot's decision to follow these signals. The algorithms are validated in the pilot-in-the loop medium fidelity simulation experiment.

Prediction of active control of subsonic centrifugal compressor rotating stall

Science.gov (United States)

Lawless, Patrick B.; Fleeter, Sanford

1993-01-01

A mathematical model is developed to predict the suppression of rotating stall in a centrifugal compressor with a vaned diffuser. This model is based on the employment of a control vortical waveform generated upstream of the impeller inlet to damp weak potential disturbances that are the early stages of rotating stall. The control system is analyzed by matching the perturbation pressure in the compressor inlet and exit flow fields with a model for the unsteady behavior of the compressor. The model was effective at predicting the stalling behavior of the Purdue Low Speed Centrifugal Compressor for two distinctly different stall patterns. Predictions made for the effect of a controlled inlet vorticity wave on the stability of the compressor show that for minimum control wave magnitudes, on the order of the total inlet disturbance magnitude, significant damping of the instability can be achieved. For control waves of sufficient amplitude, the control phase angle appears to be the most important factor in maintaining a stable condition in the compressor.

An archival analysis of stall warning system effectiveness during airborne icing encounters

Science.gov (United States)

Maris, John Michael

An archival study was conducted to determine the influence of stall warning system performance on aircrew decision-making outcomes during airborne icing encounters. A Conservative Icing Response Bias (CIRB) model was developed to explain the historical variability in aircrew performance in the face of airframe icing. The model combined Bayes' Theorem with Signal Detection Theory (SDT) concepts to yield testable predictions that were evaluated using a Binary Logistic Regression (BLR) multivariate technique applied to two archives: the NASA Aviation Safety Reporting System (ASRS) incident database, and the National Transportation Safety Board (NTSB) accident databases, both covering the period January 1, 1988 to October 2, 2015. The CIRB model predicted that aircrew would experience more incorrect response outcomes in the face of missed stall warnings than with stall warning False Alarms. These predicted outcomes were observed at high significance levels in the final sample of 132 NASA/NTSB cases. The CIRB model had high sensitivity and specificity, and explained 71.5% (Nagelkerke R2) of the variance of aircrew decision-making outcomes during the icing encounters. The reliability and validity metrics derived from this study suggest indicate that the findings are generalizable to the population of U.S. registered turbine-powered aircraft. These findings suggest that icing-related stall events could be reduced if the incidence of stall warning Misses could be minimized. Observed stall warning Misses stemmed from three principal causes: aerodynamic icing effects, which reduced the stall angle-of-attack (AoA) to below the stall warning calibration threshold; tail stalls, which are not monitored by contemporary protection systems; and icing-induced system issues (such as frozen pitot tubes), which compromised stall warning system effectiveness and airframe envelope protections. Each of these sources of missed stall warnings could be addressed by Aerodynamic Performance

Dynamic Characteristics of Rotating Stall in Mixed Flow Pump

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Xiaojun Li

2013-01-01

Full Text Available Rotating stall, a phenomenon that causes flow instabilities and pressure hysteresis by propagating at some fraction of the impeller rotational speed, can occur in centrifugal impellers, mixed impellers, radial diffusers, or axial diffusers. Despite considerable efforts devoted to the study of rotating stall in pumps, the mechanics of this phenomenon are not sufficiently understood. The propagation mechanism and onset of rotating stall are not only affected by inlet flow but also by outlet flow as well as the pressure gradient in the flow passage. As such, the complexity of these concepts is not covered by the classical explanation. To bridge this research gap, the current study investigated prerotation generated at the upstream of the impeller, leakage flow at the tip clearance between the casing and the impeller, and strong reserve flow at the inlet of the diffuser. Understanding these areas will clarify the origin of the positive slope of the head-flow performance curve for a mixed flow pump. Nonuniform pressure distribution and adverse pressure gradient were also introduced to evaluate the onset and development of rotating stall within the diffuser.

RFWD3-Dependent Ubiquitination of RPA Regulates Repair at Stalled Replication Forks.

Science.gov (United States)

Elia, Andrew E H; Wang, David C; Willis, Nicholas A; Boardman, Alexander P; Hajdu, Ildiko; Adeyemi, Richard O; Lowry, Elizabeth; Gygi, Steven P; Scully, Ralph; Elledge, Stephen J

2015-10-15

We have used quantitative proteomics to profile ubiquitination in the DNA damage response (DDR). We demonstrate that RPA, which functions as a protein scaffold in the replication stress response, is multiply ubiquitinated upon replication fork stalling. Ubiquitination of RPA occurs on chromatin, involves sites outside its DNA binding channel, does not cause proteasomal degradation, and increases under conditions of fork collapse, suggesting a role in repair at stalled forks. We demonstrate that the E3 ligase RFWD3 mediates RPA ubiquitination. RFWD3 is necessary for replication fork restart, normal repair kinetics during replication stress, and homologous recombination (HR) at stalled replication forks. Mutational analysis suggests that multisite ubiquitination of the entire RPA complex is responsible for repair at stalled forks. Multisite protein group sumoylation is known to promote HR in yeast. Our findings reveal a similar requirement for multisite protein group ubiquitination during HR at stalled forks in mammalian cells. Copyright © 2015 Elsevier Inc. All rights reserved.

Shallow and deep dynamic stall for flapping low Reynolds number airfoils

Energy Technology Data Exchange (ETDEWEB)

Ol, Michael V. [Wright-Patterson AFB, Air Force Research Lab., Dayton, OH (United States); Bernal, Luis; Kang, Chang-Kwon; Shyy, Wei [University of Michigan, Department of Aerospace Engineering, Ann Arbor, MI (United States)

2009-05-15

We consider a combined experimental (based on flow visualization, direct force measurement and phase-averaged 2D particle image velocimetry in a water tunnel), computational (2D Reynolds-averaged Navier-Stokes) and theoretical (Theodorsen's formula) approach to study the fluid physics of rigid-airfoil pitch-plunge in nominally two-dimensional conditions. Shallow-stall (combined pitch-plunge) and deep-stall (pure-plunge) are compared at a reduced frequency commensurate with flapping-flight in cruise in nature. Objectives include assessment of how well attached-flow theory can predict lift coefficient even in the presence of significant separation, and how well 2D velocimetry and 2D computation can mutually validate one another. The shallow-stall case shows promising agreement between computation and experiment, while in the deep-stall case, the computation's prediction of flow separation lags that of the experiment, but eventually evinces qualitatively similar leading edge vortex size. Dye injection was found to give good qualitative match with particle image velocimetry in describing leading edge vortex formation and return to flow reattachment, and also gave evidence of strong spanwise growth of flow separation after leading-edge vortex formation. Reynolds number effects, in the range of 10,000-60,000, were found to influence the size of laminar separation in those phases of motion where instantaneous angle of attack was well below stall, but have limited effect on post-stall flowfield behavior. Discrepancy in lift coefficient time history between experiment, theory and computation was mutually comparable, with no clear failure of Theodorsen's formula. This is surprising and encouraging, especially for the deep-stall case, because the theory's assumptions are clearly violated, while its prediction of lift coefficient remains useful for capturing general trends. (orig.)

FBH1 Catalyzes Regression of Stalled Replication Forks

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Kasper Fugger

2015-03-01

Full Text Available DNA replication fork perturbation is a major challenge to the maintenance of genome integrity. It has been suggested that processing of stalled forks might involve fork regression, in which the fork reverses and the two nascent DNA strands anneal. Here, we show that FBH1 catalyzes regression of a model replication fork in vitro and promotes fork regression in vivo in response to replication perturbation. Cells respond to fork stalling by activating checkpoint responses requiring signaling through stress-activated protein kinases. Importantly, we show that FBH1, through its helicase activity, is required for early phosphorylation of ATM substrates such as CHK2 and CtIP as well as hyperphosphorylation of RPA. These phosphorylations occur prior to apparent DNA double-strand break formation. Furthermore, FBH1-dependent signaling promotes checkpoint control and preserves genome integrity. We propose a model whereby FBH1 promotes early checkpoint signaling by remodeling of stalled DNA replication forks.

Prevalence of lameness among dairy cattle in Wisconsin as a function of housing type and stall surface.

Science.gov (United States)

Cook, Nigel B

2003-11-01

To determine the prevalence of lameness as a function of season (summer vs winter), housing type (free stalls vs tie stalls), and stall surface (sand vs any other surface) among lactating dairy cows in Wisconsin. Epidemiologic survey. 3,621 lactating dairy cows in 30 herds. Herds were visited once during the summer and once during the winter, and a locomotion score ranging from 1 (no gait abnormality) to 4 (severe lameness) was assigned to all lactating cows. Cows with a score of 3 or 4 were considered to be clinically lame. Mean +/- SD herd lameness prevalence was 21.1 +/- 10.5% during the summer and 23.9 +/- 10.7% during the winter; these values were significantly different. During the winter, mean prevalence of lameness in free-stall herds with non-sand stall surfaces (33.7%) was significantly higher than prevalences in free-stall herds with sand stall surfaces (21.2%), tie-stall herds with non-sand stall surfaces (21.7%), and tie-stall herds with sand stall surfaces (12.1%). Results suggest that the prevalence of lameness among dairy cattle in Wisconsin is higher than previously thought and that lameness prevalence is associated with season, housing type, and stall surface.

Effects of laminar separation bubbles and turbulent separation on airfoil stall

Energy Technology Data Exchange (ETDEWEB)

Dini, P. [Carleton College, Northfield, MN (United States); Coiro, D.P. [Universita di Napoli (Italy)

1997-12-31

An existing two-dimensional, interactive, stall prediction program is extended by improving its laminar separation bubble model. The program now accounts correctly for the effects of the bubble on airfoil performance characteristics when it forms at the mid-chord and on the leading edge. Furthermore, the model can now predict bubble bursting on very sharp leading edges at high angles of attack. The details of the model are discussed in depth. Comparisons of the predicted stall and post-stall pressure distributions show excellent agreement with experimental measurements for several different airfoils at different Reynolds numbers.

Analysis of the Unsteady Flow Field in a Centrifugal Compressor from Peak Efficiency to Near Stall with Full-Annulus Simulations

Directory of Open Access Journals (Sweden)

Yannick Bousquet

2014-01-01

Full Text Available This study concerns a 2.5 pressure ratio centrifugal compressor stage consisting of a splittered unshrouded impeller and a vaned diffuser. The aim of this paper is to investigate the modifications of the flow structure when the operating point moves from peak efficiency to near stall. The investigations are based on the results of unsteady three-dimensional simulations, in a calculation domain comprising all the blade. A detailed analysis is given in the impeller inducer and in the vaned diffuser entry region through time-averaged and unsteady flow field. In the impeller inducer, this study demonstrates that the mass flow reduction from peak efficiency to near stall leads to intensification of the secondary flow effects. The low momentum fluid accumulated near the shroud interacts with the main flow through a shear layer zone. At near stall condition, the interface between the two flow structures becomes unstable leading to vortices development. In the diffuser entry region, by reducing the mass flow, the high incidence angle from the impeller exit induces a separation on the diffuser vane suction side. At near stall operating point, vorticity from the separation is shed into vortex cores which are periodically formed and convected downstream along the suction side.

Visualization and PIV measurement of unsteady flow around a darrieus wind turbine in dynamic stall

Energy Technology Data Exchange (ETDEWEB)

Shibuya, Satoshi; Fujisawa, Nobuyuki; Takano, Tsuyoshi [Dept. of Mechanical and Production Engineering, Niigata Univ., Niigata (Japan)

1999-07-01

Flow around a Darrieus wind turbine in dynamic stall is studied by flow visualization and PIV (particle image velocimeter) measurement in a rotating frame of reference, which allows the successive observation of the dynamic stall over the blade. The qualitative features of the flow field in dynamic stall observed by the flow visualization, such as the formation and shedding of the stall vortices, are quantitatively reproduced in the instantaneous velocity distributions near the blade by using PIV. These results indicate that two pairs of stall vortices are generated from the blade during one rotation of the blade and that the size and the generating blade angle of the stall vortices are enlarged as the tip-speed ratio decreases. These stall vortices are produced by the in-flow motion from the outer surface to the inner surface through the trailing edge of the blade and the flow separation over the inner surface of the blade. (author)

An airloads theory for morphing airfoils in dynamic stall with experimental correlation

Science.gov (United States)

Ahaus, Loren A.

Helicopter rotor blades frequently encounter dynamic stall during normal flight conditions, limiting the applicability of classical thin-airfoil theory at large angles of attack. Also, it is evident that because of the largely different conditions on the advancing and retreating sides of the rotor, future rotorcraft may incorporate dynamically morphing airfoils (trailing-edge aps, dynamic camber, dynamic droop, etc.). Reduced-order aerodynamic models are needed for preliminary design and ight simulation. A unified model for predicting the airloads on a morphing airfoil in dynamic stall is presented, consisting of three components. First, a linear airloads theory allows for arbitrary airfoil deformations consistent with a morphing airfoil. Second, to capture the effects of the wake, the airloads theory is coupled to an induced ow model. Third, the overshoot and time delay associated with dynamic stall are modeled by a second-order dynamic filter, along the lines of the ONERA dynamic stall model. This paper presents a unified airloads model that allows arbitrary airfoil morphing with dynamic stall. Correlations with experimental data validate the theory.

Stall Margin Improvement in a Centrifugal Compressor through Inducer Casing Treatment

Directory of Open Access Journals (Sweden)

V. V. N. K. Satish Koyyalamudi

2016-01-01

Full Text Available The increasing trend of high stage pressure ratio with increased aerodynamic loading has led to reduction in stable operating range of centrifugal compressors with stall and surge initiating at relatively higher mass flow rates. The casing treatment technique of stall control is found to be effective in axial compressors, but very limited research work is published on the application of this technique in centrifugal compressors. Present research was aimed to investigate the effect of casing treatment on the performance and stall margin of a high speed, 4 : 1 pressure ratio centrifugal compressor through numerical simulations using ANSYS CFX software. Three casing treatment configurations were developed and incorporated in the shroud over the inducer of the impeller. The predicted performance of baseline compressor (without casing treatment was in good agreement with published experimental data. The compressor with different inducer casing treatment geometries showed varying levels of stall margin improvement, up to a maximum of 18%. While the peak efficiency of the compressor with casing treatment dropped by 0.8%–1% compared to the baseline compressor, the choke mass flow rate was improved by 9.5%, thus enhancing the total stable operating range. The inlet configuration of the casing treatment was found to play an important role in stall margin improvement.

Dynamic Stall Control on the Wind Turbine Airfoil via a Co-Flow Jet

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He-Yong Xu

2016-06-01

Full Text Available Dynamic stall control of a S809 airfoil is numerically investigated by implementing a co-flow jet (CFJ. The numerical methods of the solver are validated by comparing results with the baseline experiment as well as a NACA 6415-based CFJ experiment, showing good agreement in both static and dynamic characteristics. The CFJ airfoil with inactive jet is simulated to study the impact that the jet channel imposes upon the dynamic characteristics. It is shown that the presence of a long jet channel could cause a negative effect of decreasing lift and increasing drag, leading to fluctuating extreme loads in terms of drag and moment. The main focus of the present research is the investigation of the dynamic characteristics of the CFJ airfoil with three different jet momentum coefficients, which are compared with the baseline, giving encouraging results. Dynamic stall can be greatly suppressed, showing a very good control performance of significantly increased lift and reduced drag and moment. Analysis of the amplitude of variation in the aerodynamic coefficients indicates that the fluctuating extreme aerodynamic loads are significantly alleviated, which is conducive to structural reliability and improved life cycle. The energy consumption analysis shows that the CFJ concept is applicable and economical in controlling dynamic stall.

Development of High Speed Imaging and Analysis Techniques Compressible Dynamics Stall

Science.gov (United States)

Chandrasekhara, M. S.; Carr, L. W.; Wilder, M. C.; Davis, Sanford S. (Technical Monitor)

1996-01-01

Dynamic stall has limited the flight envelope of helicopters for many years. The problem has been studied in the laboratory as well as in flight, but most research, even in the laboratory, has been restricted to surface measurement techniques such as pressure transducers or skin friction gauges, except at low speed. From this research, it became apparent that flow visualization tests performed at Mach numbers representing actual flight conditions were needed if the complex physics associated with dynamic stall was to be properly understood. However, visualization of the flow field during compressible conditions required carefully aligned and meticulously reconstructed holographic interferometry. As part of a long-range effort focused on exposing of the physics of compressible dynamic stall, a research wind tunnel was developed at NASA Ames Research Center which permits visual access to the full flow field surrounding an oscillating airfoil during compressible dynamic stall. Initially, a stroboscopic schlieren technique was used for visualization of the stall process, but the primary research tool has been point diffraction interferometry(PDI), a technique carefully optimized for use in th is project. A review of the process of development of PDI will be presented in the full paper. One of the most valuable aspects of PDI is the fact that interferograms are produced in real time on a continuous basis. The use of a rapidly-pulsed laser makes this practical; a discussion of this approach will be presented in the full paper. This rapid pulsing(up to 40,000 pulses/sec) produces interferograms of the rapidly developing dynamic stall field in sufficient resolution(both in space and time) that the fluid physics of the compressible dynamic stall flowfield can be quantitatively determined, including the gradients of pressure in space and time. This permits analysis of the influence of the effect of pitch rate, Mach number, Reynolds number, amplitude of oscillation, and other

Analysis of Low Speed Stall Aerodynamics of a Swept Wing with Laminar Flow Glove

Science.gov (United States)

Bui, Trong T.

2014-01-01

Reynolds-Averaged Navier-Stokes (RANS) computational fluid dynamics (CFD) analysis was conducted to study the low-speed stall aerodynamics of a GIII aircraft's swept wing modified with a laminar-flow wing glove. The stall aerodynamics of the gloved wing were analyzed and compared with the unmodified wing for the flight speed of 120 knots and altitude of 2300 ft above mean sea level (MSL). The Star-CCM+ polyhedral unstructured CFD code was first validated for wing stall predictions using the wing-body geometry from the First American Institute of Aeronautics and Astronautics (AIAA) CFD High-Lift Prediction Workshop. It was found that the Star-CCM+ CFD code can produce results that are within the scattering of other CFD codes considered at the workshop. In particular, the Star-CCM+ CFD code was able to predict wing stall for the AIAA wing-body geometry to within 1 degree of angle of attack as compared to benchmark wind-tunnel test data. Current results show that the addition of the laminar-flow wing glove causes the gloved wing to stall much earlier than the unmodified wing. Furthermore, the gloved wing has a different stall characteristic than the clean wing, with no sharp lift drop-off at stall for the gloved wing.

Analysis of Low-Speed Stall Aerodynamics of a Swept Wing with Laminar-Flow Glove

Science.gov (United States)

Bui, Trong T.

2014-01-01

Reynolds-Averaged Navier-Stokes (RANS) computational fluid dynamics (CFD) analysis was conducted to study the low-speed stall aerodynamics of a GIII aircraft's swept wing modified with a laminar-flow wing glove. The stall aerodynamics of the gloved wing were analyzed and compared with the unmodified wing for the flight speed of 120 knots and altitude of 2300 ft above mean sea level (MSL). The Star-CCM+ polyhedral unstructured CFD code was first validated for wing stall predictions using the wing-body geometry from the First American Institute of Aeronautics and Astronautics (AIAA) CFD High-Lift Prediction Workshop. It was found that the Star-CCM+ CFD code can produce results that are within the scattering of other CFD codes considered at the workshop. In particular, the Star-CCM+ CFD code was able to predict wing stall for the AIAA wing-body geometry to within 1 degree of angle of attack as compared to benchmark wind-tunnel test data. Current results show that the addition of the laminar-flow wing glove causes the gloved wing to stall much earlier than the unmodified wing. Furthermore, the gloved wing has a different stall characteristic than the clean wing, with no sharp lift drop-off at stall for the gloved wing.

Stall inception and warning in a single-stage transonic axial compressor with axial skewed slot casing treatment

International Nuclear Information System (INIS)

Lim, Byeung Jun; Kwon, Se Jin; Park, Tae Choon

2014-01-01

Characteristic changes in the stall inception in a single-stage transonic axial compressor with an axial skewed slot casing treatment were investigated experimentally. A rotating stall occurred intermittently in a compressor with an axial skewed slot, whereas spike-type rotating stalls occurred in the case of smooth casing. The axial skewed slot suppressed stall cell growth and increased the operating range. A mild surge, the frequency of which is the Helmholtz frequency of the compressor system, occurred with the rotating stall. The irregularity in the pressure signals at the slot bottom increased decreasing flow rate. An autocorrelation-based stall warning method was applied to the measured pressure signals. Results estimate and warn against the stall margin in a compressor with an axial skewed slot.

Stability Analysis for Rotating Stall Dynamics in Axial Flow Compressors

Science.gov (United States)

1999-01-01

modes determines collectively local stability of the compressor model. Explicit conditions are obtained for local stability of rotating stall which...critical modes determines the stability for rotating stall collectively . We point out that although in a special case our stability condition for...strict crossing assumption implies that the zero solution changes its stability as ~, crosses ~’c. For instance, odk (yc ) > 0 implies that the zero

Modeling dynamic stall on wind turbine blades under rotationally augmented flow fields

DEFF Research Database (Denmark)

Guntur, Srinivas; Sørensen, Niels N.; Schreck, Scott

2016-01-01

a reduced order dynamic stall model that uses rotationally augmented steady-state polars obtained from steady Phase VI experimental sequences, instead of the traditional two-dimensional, non-rotating data. The aim of this work is twofold. First, the blade loads estimated by the DDES simulations are compared...... Experiment Phase VI experimental data, including constant as well as continuously pitching blade conditions during axial operation; (2) data from unsteady delayed detached eddy simulations (DDES) carried out using the Technical University of Denmark’s in-house flow solver Ellipsys3D; and (3) data from...... with those from the dynamic stall model. This allowed the differences between the stall phenomenon on the inboard parts of harmonically pitching blades on a rotating wind turbine and the classic dynamic stall representation in two-dimensional flow to be investigated. Results indicated a good qualitative...

Experimental investigation on the effects of non-cyclical frequency and amplitude variation on dynamic stall

Science.gov (United States)

Heintz, Kyle C.

An experimental study of a cambered airfoil undergoing non-cyclical, transient pitch trajectories and the resulting effects on the dynamic stall phenomenon is presented. Surface pressure measurements and airfoil incidence angle are acquired simultaneously to resolve instantaneous aerodynamic load coefficients at Mach numbers ranging from 0.2 to 0.4. Derived from these coefficients are various formulations of the aerodynamic damping factor, referred to copiously throughout. Using a two-motor mechanism, each providing independent frequency and amplitude input to the airfoil, unique pitch motions can be implemented by actively controlling the phase between inputs. This work primarily focuses on three pitch motion schemas, the first of which is a "chirp" style trajectory featuring concurrent exponential frequency growth and amplitude decay. Second, these parameters are tested separately to determine their individual contributions. Lastly, a novel dual harmonic pitch motion is devised which rapidly traverses dynamic stall regimes on an inter-cycle basis by modulating the static-stall penetration angle. Throughout all results presented, there is evidence that for consecutive pitch-cycles, the process of dynamic stall is affected when prior oscillations prior have undergone deeper stall-penetration angles. In other words when stall-penetration is descending, retreating from a regime of light or deep stall, statistics of load coefficients, such as damping coefficient, maximum lift, minimum quarter-chord moment, and their phase relationships, do not match the values seen when stall-penetration was growing. The outcomes herein suggest that the airfoil retains some memory of previous flow separation which has the potential to change the influence of the dynamic stall vortex.

Enhancing BEM simulations of a stalled wind turbine using a 3D correction model

Science.gov (United States)

Bangga, Galih; Hutomo, Go; Syawitri, Taurista; Kusumadewi, Tri; Oktavia, Winda; Sabila, Ahmad; Setiadi, Herlambang; Faisal, Muhamad; Hendranata, Yongki; Lastomo, Dwi; Putra, Louis; Kristiadi, Stefanus; Bumi, Ilmi

2018-03-01

Nowadays wind turbine rotors are usually employed with pitch control mechanisms to avoid deep stall conditions. Despite that, wind turbines often operate under pitch fault situation causing massive flow separation to occur. Pure Blade Element Momentum (BEM) approaches are not designed for this situation and inaccurate load predictions are already expected. In the present studies, BEM predictions are improved through the inclusion of a stall delay model for a wind turbine rotor operating under pitch fault situation of -2.3° towards stall. The accuracy of the stall delay model is assessed by comparing the results with available Computational Fluid Dynamics (CFD) simulations data.

Direct numerical simulation of a NACA0012 in full stall

International Nuclear Information System (INIS)

Rodríguez, I.; Lehmkuhl, O.; Borrell, R.; Oliva, A.

2013-01-01

Highlights: • Coherent structures at transitional and supercritical wake modes are presented. • Vortex shedding is detected in both wake modes. • KH instabilities and vortex shedding frequencies are identified. • Low-frequency flapping of the shear-layer is also detected after stall. • Local pressure distribution at both AOA is coherent with experimental observations. -- Abstract: This work aims at investigating the mechanisms of separation and the transition to turbulence in the separated shear-layer of aerodynamic profiles, while at the same time to gain insight into coherent structures formed in the separated zone at low-to-moderate Reynolds numbers. To do this, direct numerical simulations of the flow past a NACA0012 airfoil at Reynolds numbers Re = 50,000 (based on the free-stream velocity and the airfoil chord) and angles of attack AOA = 9.25° and AOA = 12° have been carried out. At low-to-moderate Reynolds numbers, NACA0012 exhibits a combination of leading-edge/trailing-edge stall which causes the massive separation of the flow on the suction side of the airfoil. The initially laminar shear layer undergoes transition to turbulence and vortices formed are shed forming a von Kármán like vortex street in the airfoil wake. The main characteristics of this flow together with its main features, including power spectra of a set of selected monitoring probes at different positions on the suction side and in the wake of the airfoil are provided and discussed in detail

Physics of Prestall Propagating Disturbances in Axial Compressors and Their Potential as a Stall Warning Indicator

Directory of Open Access Journals (Sweden)

Mario Eck

2017-03-01

Full Text Available Axial compressors in aero engines are prone to suffering a breakdown of orderly flow when operating at the peak of the pressure rise characteristic. The damaging potential of separated flows is why a safe distance has to be left between every possible operating point and an operating point at which stall occurs. During earlier investigations of stall inception mechanisms, a new type of prestall instability has been found. In this study, it could be demonstrated that the prestall instability characterised by discrete flow disturbances can be clearly assigned to the subject of “Rotating Instabilities”. Propagating disturbances are responsible for the rise in blade passing irregularity. If the mass flow is reduced successively, the level of irregularity increases until the prestall condition devolves into rotating stall. The primary objective of the current work is to highlight the basic physics behind these prestall disturbances by complementary experimental and numerical investigations. Before reaching the peak of the pressure rise characteristic flow, disturbances appear as small vortex tubes with one end attached to the casing and the other attached to the suction surface of the rotor blade. These vortex structures arise when the entire tip region is affected by blockage and at the same time the critical rotor incidence is not exceeded in this flow regime. Furthermore, a new stall indicator was developed by applying statistical methods to the unsteady pressure signal measured over the rotor blade tips, thus granting a better control of the safety margin.

A theory of post-stall transients in axial compression systems. I - Development of equations

Science.gov (United States)

Moore, F. K.; Greitzer, E. M.

1985-01-01

An approximate theory is presented for post-stall transients in multistage axial compression systems. The theory leads to a set of three simultaneous nonlinear third-order partial differential equations for pressure rise, and average and disturbed values of flow coefficient, as functions of time and angle around the compressor. By a Galerkin procedure, angular dependence is averaged, and the equations become first order in time. These final equations are capable of describing the growth and possible decay of a rotating-stall cell during a compressor mass-flow transient. It is shown how rotating-stall-like and surgelike motions are coupled through these equations, and also how the instantaneous compressor pumping characteristic changes during the transient stall process.

Evaluating Classroom Interaction with the iPad®: An Updated Stalling's Tool

Science.gov (United States)

MacKinnon, Gregory; Schep, Lourens; Borden, Lisa Lunney; Murray-Orr, Anne; Orr, Jeff; MacKinnon, Paula

2016-01-01

A large study of classrooms in the Caribbean context necessitated the use of a validated classroom observation tool. In practice, the paper-version Stalling's instrument (Stallings & Kaskowitz 1974) presented specific challenges with respect to (a) facile data collection and (b) qualitative observations of classrooms. In response to these…

Active Suppression of Rotating Stall Inception with Distributed Jet Actuation

Directory of Open Access Journals (Sweden)

Huu Duc Vo

2007-01-01

Full Text Available An analytical and experimental investigation of the effectiveness of full-span distributed jet actuation for active suppression of long length-scale rotating stall inception is carried out. Detailed modeling and experimental verification highlight the important effects of mass addition, discrete injectors, and feedback dynamics, which may be overlooked in preliminary theoretical studies of active control with jet injection. A model of the compression system incorporating nonideal injection and feedback dynamics is verified with forced response measurements to predict the right trends in the movement of the critical pole associated with the stall precursor. Active control experiments with proportional feedback control show that the predicted stall precursors are suppressed to give a 5.5% range extension in compressor flow coefficient. In addition, results suggest that the proposed model could be used to design a more sophisticated controller to further improve performance while reducing actuator bandwidth requirements.

Development and application of a dynamic stall model for rotating wind turbine blades

International Nuclear Information System (INIS)

Xu, B F; Yuan, Y; Wang, T G

2014-01-01

In unsteady conditions of wind turbines, both the dynamic stall phenomenon and the three-dimensional (3D) rotational effect affect the rotor aerodynamics. The dynamic stall mechanism for rotating wind turbine blades is first investigated. Through the comparison of the aerodynamic data between the rotating blade and the two-dimensional (2D) airfoil, the normal force slope in the attached flow and the separation point expression in the separated flow are modified in the Beddoes-Leishman (B-L) dynamic stall model for rotating NREL wind turbine blades. The modified model is validated by the comparison between the calculation results and the experimental results of the lift and drag coefficients at different radial positions. Both the hysteresis loop shapes and the calculation values are closer to the experiment than the 2D dynamic stall model. The present dynamic stall model is then coupled to a free vortex wake model. The coupled model is used to calculate the unsteady blade aerodynamic loads and the low speed shaft torque of the NREL wind turbine in a yawed condition. The accuracy is greatly improved by the corrections presented in the paper

Replication Stalling and Heteroduplex Formation within CAG/CTG Trinucleotide Repeats by Mismatch Repair

KAUST Repository

Viterbo, David; Michoud, Gregoire; Mosbach, Valentine; Dujon, Bernard; Richard, Guy-Franck

2016-01-01

Trinucleotide repeat expansions are responsible for at least two dozen neurological disorders. Mechanisms leading to these large expansions of repeated DNA are still poorly understood. It was proposed that transient stalling of the replication fork by the repeat tract might trigger slippage of the newly-synthesized strand over its template, leading to expansions or contractions of the triplet repeat. However, such mechanism was never formally proven. Here we show that replication fork pausing and CAG/CTG trinucleotide repeat instability are not linked, stable and unstable repeats exhibiting the same propensity to stall replication forks when integrated in a yeast natural chromosome. We found that replication fork stalling was dependent on the integrity of the mismatch-repair system, especially the Msh2p-Msh6p complex, suggesting that direct interaction of MMR proteins with secondary structures formed by trinucleotide repeats in vivo, triggers replication fork pauses. We also show by chromatin immunoprecipitation that Msh2p is enriched at trinucleotide repeat tracts, in both stable and unstable orientations, this enrichment being dependent on MSH3 and MSH6. Finally, we show that overexpressing MSH2 favors the formation of heteroduplex regions, leading to an increase in contractions and expansions of CAG/CTG repeat tracts during replication, these heteroduplexes being dependent on both MSH3 and MSH6. These heteroduplex regions were not detected when a mutant msh2-E768A gene in which the ATPase domain was mutated was overexpressed. Our results unravel two new roles for mismatch-repair proteins: stabilization of heteroduplex regions and transient blocking of replication forks passing through such repeats. Both roles may involve direct interactions between MMR proteins and secondary structures formed by trinucleotide repeat tracts, although indirect interactions may not be formally excluded.

Replication Stalling and Heteroduplex Formation within CAG/CTG Trinucleotide Repeats by Mismatch Repair

KAUST Repository

Viterbo, David

2016-03-16

Trinucleotide repeat expansions are responsible for at least two dozen neurological disorders. Mechanisms leading to these large expansions of repeated DNA are still poorly understood. It was proposed that transient stalling of the replication fork by the repeat tract might trigger slippage of the newly-synthesized strand over its template, leading to expansions or contractions of the triplet repeat. However, such mechanism was never formally proven. Here we show that replication fork pausing and CAG/CTG trinucleotide repeat instability are not linked, stable and unstable repeats exhibiting the same propensity to stall replication forks when integrated in a yeast natural chromosome. We found that replication fork stalling was dependent on the integrity of the mismatch-repair system, especially the Msh2p-Msh6p complex, suggesting that direct interaction of MMR proteins with secondary structures formed by trinucleotide repeats in vivo, triggers replication fork pauses. We also show by chromatin immunoprecipitation that Msh2p is enriched at trinucleotide repeat tracts, in both stable and unstable orientations, this enrichment being dependent on MSH3 and MSH6. Finally, we show that overexpressing MSH2 favors the formation of heteroduplex regions, leading to an increase in contractions and expansions of CAG/CTG repeat tracts during replication, these heteroduplexes being dependent on both MSH3 and MSH6. These heteroduplex regions were not detected when a mutant msh2-E768A gene in which the ATPase domain was mutated was overexpressed. Our results unravel two new roles for mismatch-repair proteins: stabilization of heteroduplex regions and transient blocking of replication forks passing through such repeats. Both roles may involve direct interactions between MMR proteins and secondary structures formed by trinucleotide repeat tracts, although indirect interactions may not be formally excluded.

Simulasi Numerik Dynamic Stall Pada Airfoil Yang Berosilasi

Directory of Open Access Journals (Sweden)

Galih S.T.A. Bangga

2012-09-01

Full Text Available Kebutuhan analisa pada sudu helikopter, kompresor, kincir angin dan struktur streamline lainya yang beroperasi pada angle of attack yang tinggi dan melibatkan instationary effects yang disebut dynamic stall menjadi semakin penting. Fenomena ini ditandai dengan naiknya dynamic lift melewati static lift maksimum pada critical static stall angle, vortex yang terbentuk pada leading edge mengakibatkan naiknya suction contribution yang kemudian terkonveksi sepanjang permukaan hingga mencapai trailling edge diikuti terbentuknya trailling edge vortex yang menunjukkan terjadinya lift stall. Fenomena ini sangat berbahaya terhadap struktur airfoil itu sendiri. Secara umum, beban fatique yang ditimbulkan oleh adanya efek histerisis karena fluktuasi gaya lift akibat induksi vibrasi lebih besar dibandingkan kondisi statis. Simulasi numerik dilakukan secara 2D dengan menggunakan profil Boeing-Vertol V23010-1.58 pada α0 = 14.92°. Standard-kω dan SST-kω digunakan sebagai URANS turbulence modelling. Model osilasi dari airfoil disusun dalam suatu user defined function (UDF. Gerakan meshing beserta airfoil diakomodasi dengan menggunakan dynamic mesh approach. Simulasi numerik menunjukkan bahwa, model SST-kω menunjukkan performa yang lebih baik dibandingkan dengan Standard-kω. Fenomena travelling vortex yang terjadi mampu ditangkap dengan baik, meski pada angle of attack yang tinggi URANS turbulence model gagal memprediksikan fenomena yang terjadi karena dominasi efek 3D.

Effects of alley and stall surfaces on indices of claw and leg health in dairy cattle housed in a free-stall barn.

Science.gov (United States)

Vokey, F J; Guard, C L; Erb, H N; Galton, D M

2001-12-01

A 15-wk 2 x 3 factorial trial in a university dairy herd compared the effects of two alley surfaces and three free-stall beds on indices of lameness. Alley surfaces were grooved concrete (Ct) or 1.9-cm-thick interlocking rubber mats (R). Stalls were deep sand (S), rubber mattresses (M), or concrete (C). Mattress and concrete stalls were bedded with sawdust. At wk 1 and 15, the hind claws and hocks of 120 primi- (n = 69) and multiparous (n = 51) cows were scored for lesions and three claw measurements (dorsal wall length, heel depth, and toe angle) were recorded. Rates of lateral and medial claw growth and wear were calculated by measuring the migration of a reference mark away from the coronet. Digital photographs of claw surfaces were used to rescore claw lesions. Clinical lameness was evaluated by assigning a locomotion score from 1 to 4 to each cow during wk 1, 5, 10, and 14. Digital dermatitis (present/not present) and interdigital dermatitis (mild, moderate, or severe) were recorded at wk 15. The number of days that cows spent in a hospital barn was recorded. Before assignment, cows were professionally foot trimmed, sorted by initial claw lesion score, and then randomized in consecutive blocks of three to stall treatments. Photograph scores were highly repeatable. Nonparametric statistical techniques were used for analyses of rank data. Claw lesion score increased significantly for all treatment groups except RC and RS; however, when early lactation cows were excluded, no differences were found between treatment groups. Hock scores increased significantly more for cows in CtC than in CtS or RS. Significantly more animals from RC spent more than 10 d in the hospital pen compared with RM and RS. Groups did not significantly differ for clinical lameness. Cows in RS and RC had significantly lower rates for lateral claw net growth than those in CtM. Having moderate or severe interdigital dermatitis at wk 15 was associated with greater increases in claw lesion score

Cow comfort in tie-stalls: increased depth of shavings or straw bedding increases lying time.

Science.gov (United States)

Tucker, C B; Weary, D M; von Keyserlingk, M A G; Beauchemin, K A

2009-06-01

Over half of US dairy operations use tie-stalls, but these farming systems have received relatively little research attention in terms of stall design and management. The current study tested the effects of the amount of 2 bedding materials, straw and shavings, on dairy cattle lying behavior. The effects of 4 levels of shavings, 3, 9, 15, and 24 kg/stall (experiment 1, n = 12), and high and low levels of straw in 2 separate experiments: 1, 3, 5, and 7 kg/stall (experiment 2, n = 12) and 0.5, 1, 2, and 3 kg/stall (experiment 3, n = 12) were assessed. Treatments were compared using a crossover design with lactating cows housed in tie-stalls fitted with mattresses. Treatments were applied for 1 wk. Total lying time, number of lying bouts, and the length of each lying bout was recorded with data loggers. In experiment 1, cows spent 3 min more lying down for each additional kilogram of shavings (11.0, 11.7, 11.6, and 12.1 +/- 0.24 h/d for 3, 9, 15, and 24 kg/stall shavings, respectively). In experiment 2, cows increased lying time by 12 min for every additional kilogram of straw (11.2, 12.0, 11.8, and 12.4 +/- 0.24 h/d for 1, 3, 5, and 7 kg/stall of straw, respectively). There were no differences in lying behavior among the lower levels of straw tested in experiment 3 (11.7 +/- 0.32 h/d). These results indicated that additional bedding above a scant amount improves cow comfort, as measured by lying time, likely because a well-bedded surface is more compressible.

Resemblance and investment in children.

Science.gov (United States)

Dolinska, Barbara

2013-01-01

According to evolutionary explanations men hardly ever are absolutely certain about their biological fatherhood therefore they must seek various sources of information to subjectively establish whether they are the genetic fathers of the children they raise. Apicella and Marlowe (2004) showed that fathers who perceived greater similarity between their children and themselves were willing to invest more resources (e.g., time, money, care) in their offspring presumably because the perceived resemblance indicated to the fathers their genetic relatedness with their children. The present study extended the design of Apicella and Marlowe's original study and included both fathers and mothers as participants. Parents were recruited by a female confederate at the airport and at the railway station in Wroclaw (Poland). Multiple regression analyses showed that perceived resemblance predicted parental investment in the child for both men and women. The fact that mothers' declarations of investment in their children also depended on the perceived resemblance factor is not consistent with evolutionary formulations delineated by Apicella and Marlowe (2004; 2007). Future studies must resolve the issue of whether the resemblance-investment relation in fathers results from men relaying on child's resemblance to themselves as an indicator of their own biological paternity, or whether it results from the more parsimonious phenomenon that people in general are attracted more to other people who are similar to them.

The SmpB C-terminal tail helps tmRNA to recognize and enter stalled ribosomes

Directory of Open Access Journals (Sweden)

Mickey R. Miller

2014-09-01

Full Text Available In bacteria, transfer-messenger RNA (tmRNA and SmpB comprise the most common and effective system for rescuing stalled ribosomes. Ribosomes stall on mRNA transcripts lacking stop codons and are rescued as the defective mRNA is swapped for the tmRNA template in a process known as trans-translation. The tmRNA–SmpB complex is recruited to the ribosome independent of a codon–anticodon interaction. Given that the ribosome uses robust discriminatory mechanisms to select against non-cognate tRNAs during canonical decoding, it has been hard to explain how this can happen. Recent structural and biochemical studies show that SmpB licenses tmRNA entry through its interactions with the decoding center and mRNA channel. In particular, the C-terminal tail of SmpB promotes both EFTu activation and accommodation of tmRNA, the former through interactions with 16S rRNA nucleotide G530 and the latter through interactions with the mRNA channel downstream of the A site. Here we present a detailed model of the earliest steps in trans-translation, and in light of these mechanistic considerations, revisit the question of how tmRNA preferentially reacts with stalled, non-translating ribosomes.

Combustion-Powered Actuation for Dynamic Stall Suppression - Simulations and Low-Mach Experiments

Science.gov (United States)

Matalanis, Claude G.; Min, Byung-Young; Bowles, Patrick O.; Jee, Solkeun; Wake, Brian E.; Crittenden, Tom; Woo, George; Glezer, Ari

2014-01-01

An investigation on dynamic-stall suppression capabilities of combustion-powered actuation (COMPACT) applied to a tabbed VR-12 airfoil is presented. In the first section, results from computational fluid dynamics (CFD) simulations carried out at Mach numbers from 0.3 to 0.5 are presented. Several geometric parameters are varied including the slot chordwise location and angle. Actuation pulse amplitude, frequency, and timing are also varied. The simulations suggest that cycle-averaged lift increases of approximately 4% and 8% with respect to the baseline airfoil are possible at Mach numbers of 0.4 and 0.3 for deep and near-deep dynamic-stall conditions. In the second section, static-stall results from low-speed wind-tunnel experiments are presented. Low-speed experiments and high-speed CFD suggest that slots oriented tangential to the airfoil surface produce stronger benefits than slots oriented normal to the chordline. Low-speed experiments confirm that chordwise slot locations suitable for Mach 0.3-0.4 stall suppression (based on CFD) will also be effective at lower Mach numbers.

Effect of artificial UV irradiation on spore content of stall air and fattening pig breeding

International Nuclear Information System (INIS)

Kalich, J.; Blendl, H.M.

1978-01-01

The influence of a continuous UV irradiation (emitter NN 33/89 original Hanau) during the fattening periods primarily in the bactericide region of 253.7 nm of various intensities on the spore content of air, on the state of health and on the fattening breeding of pigs was tested in two fattening procedures. The high spore number per m 3 air of over 700 000 upon occupying the stall in the first fattening procedure was reduced by 90.5% to about 70 000 after 1 week of UV irradiation, and in the second procedure, from 111 500 to 16 000, i.e. a reduction of 85.5%. The spore content of the stall air then exhibited large deviations reducing and increasing. The same deviations were recorded for dust content. There was no absolute correlation between dust and spore content of the air until the 11th week after starting UV irradiation in either test. The spore content sank in the reference stalls also without UV irradiation, by 29.9% in the first fattening procedure 1 week after occupying the stall and even by 75% in the second procedure. The spore content of the air in the reference stalls also then exhibited deviations sinking and rising as in the test stalls with UV irradiation. Here too, there was no correlation between dust and spore content of the air. The spore content in the air was 2 to 7 times higher in the reference stalls than in the test stalls. One may conclude from the tests that the promoting irradiation strength is between 15 and 20 μW/cm 2 and that short-term stool production in danish stalling, 60 μW/cm 2 are not harmful. Air disinfection with UV irradiation, can only be part of the total hygiene measures taken in veterinary medicine and may only be considered as an important link in the chain of the health promoting and increased efficient hygiene measures in the intensification of aggriculturally useful animals. (orig./AJ) [de

Modeling dynamic stall on wind turbine blades under rotationally augmented flow fields

Energy Technology Data Exchange (ETDEWEB)

Guntur, S. [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Schreck, S. [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Sorensen, N. N. [Technical Univ. of Denmark, Lyngby (Denmark); Bergami, L. [Technical Univ. of Denmark, Lyngby (Denmark)

2015-04-22

It is well known that airfoils under unsteady flow conditions with a periodically varying angle of attack exhibit aerodynamic characteristics different from those under steady flow conditions, a phenomenon commonly known as dynamic stall. It is also well known that the steady aerodynamic characteristics of airfoils in the inboard region of a rotating blade differ from those under steady two-dimensional (2D) flow conditions, a phenomenon commonly known as rotational augmentation. This paper presents an investigation of these two phenomena together in the inboard parts of wind turbine blades. This analysis is carried out using data from three sources: (1) the National Renewable Energy Laboratory’s Unsteady Aerodynamics Experiment Phase VI experimental data, including constant as well as continuously pitching blade conditions during axial operation, (2) data from unsteady Delayed Detached Eddy Simulations (DDES) carried out using the Technical University of Denmark’s in-house flow solver Ellipsys3D, and (3) data from a simplified model based on the blade element momentum method with a dynamic stall subroutine that uses rotationally augmented steady-state polars obtained from steady Phase VI experimental sequences, instead of the traditional 2D nonrotating data. The aim of this work is twofold. First, the blade loads estimated by the DDES simulations are compared to three select cases of the N sequence experimental data, which serves as a validation of the DDES method. Results show reasonable agreement between the two data in two out of three cases studied. Second, the dynamic time series of the lift and the moment polars obtained from the experiments are compared to those from the dynamic stall subroutine that uses the rotationally augmented steady polars. This allowed the differences between the stall phenomenon on the inboard parts of harmonically pitching blades on a rotating wind turbine and the classic dynamic stall representation in 2D flow to be

Study and Control of a Radial Vaned Diffuser Stall

Directory of Open Access Journals (Sweden)

Aurélien Marsan

2012-01-01

Full Text Available The aim of the present study is to evaluate the efficiency of a boundary layer suction technique in case of a centrifugal compressor stage in order to extend its stable operating range. First, an analysis of the flow pattern within the radial vaned diffuser is presented. It highlights the stall of the diffuser vanes when reaching a low massflow. A boundary layer separation in the hub-suction side corner grows when decreasing the massflow from the nominal operating point to the surge and finally leads to a massive stall. An aspiration strategy is investigated in order to control the stall. The suction slot is put in the vicinity of the saddle that originates the main separating skin-friction line, identified thanks to the analysis of the skin-friction pattern. Several aspiration massflow rates are tested, and two different modelings of the aspiration are evaluated. Finally, an efficient control is reached with a removal of only 0,1% of the global massflow and leads—from a steady-state calculations point of view—to an increase by 40% of the compressor operating range extent.

Questionnaire-based study to assess the association between management practices and mastitis within tie-stall and free-stall dairy housing systems in Switzerland

Science.gov (United States)

2013-01-01

Background Prophylactic measures are key components of dairy herd mastitis control programs, but some are only relevant in specific housing systems. To assess the association between management practices and mastitis incidence, data collected in 2011 by a survey among 979 randomly selected Swiss dairy farms, and information from the regular test day recordings from 680 of these farms was analyzed. Results The median incidence of farmer-reported clinical mastitis (ICM) was 11.6 (mean 14.7) cases per 100 cows per year. The median annual proportion of milk samples with a composite somatic cell count (PSCC) above 200,000 cells/ml was 16.1 (mean 17.3) %. A multivariable negative binomial regression model was fitted for each of the mastitis indicators for farms with tie-stall and free-stall housing systems separately to study the effect of other (than housing system) management practices on the ICM and PSCC events (above 200,000 cells/ml). The results differed substantially by housing system and outcome. In tie-stall systems, clinical mastitis incidence was mainly affected by region (mountainous production zone; incidence rate ratio (IRR) = 0.73), the dairy herd replacement system (1.27) and farmers age (0.81). The proportion of high SCC was mainly associated with dry cow udder controls (IRR = 0.67), clean bedding material at calving (IRR = 1.72), using total merit values to select bulls (IRR = 1.57) and body condition scoring (IRR = 0.74). In free-stall systems, the IRR for clinical mastitis was mainly associated with stall climate/temperature (IRR = 1.65), comfort mats as resting surface (IRR = 0.75) and when no feed analysis was carried out (IRR = 1.18). The proportion of high SSC was only associated with hand and arm cleaning after calving (IRR = 0.81) and beef producing value to select bulls (IRR = 0.66). Conclusions There were substantial differences in identified risk factors in the four models. Some of the factors were in agreement with the reported literature

Analysis of Low-Speed Stall Aerodynamics of a Business Jets Wing Using STAR-CCM+

Science.gov (United States)

Bui, Trong

2016-01-01

Reynolds-Averaged Navier-Stokes (RANS) computational fluid dynamics (CFD) analysis was conducted: to study the low-speed stall aerodynamics of a GIII aircrafts swept wing modified with (1) a laminar-flow wing glove, or (2) a seamless flap. The stall aerodynamics of these two different wing configurations were analyzed and compared with the unmodified baseline wing for low-speed flight. The Star-CCM+ polyhedral unstructured CFD code was first validated for wing stall predictions using the wing-body geometry from the First AIAA CFD High-Lift Prediction Workshop.

Nonlinear control of rotating stall and surge with axisymmetric bleed and air injection on axial flow compressors

Science.gov (United States)

Yeung, Chung-Hei (Simon)

The study of compressor instabilities in gas turbine engines has received much attention in recent years. In particular, rotating stall and surge are major causes of problems ranging from component stress and lifespan reduction to engine explosion. In this thesis, modeling and control of rotating stall and surge using bleed valve and air injection is studied and validated on a low speed, single stage, axial compressor at Caltech. Bleed valve control of stall is achieved only when the compressor characteristic is actuated, due to the fast growth rate of the stall cell compared to the rate limit of the valve. Furthermore, experimental results show that the actuator rate requirement for stall control is reduced by a factor of fourteen via compressor characteristic actuation. Analytical expressions based on low order models (2--3 states) and a high fidelity simulation (37 states) tool are developed to estimate the minimum rate requirement of a bleed valve for control of stall. A comparison of the tools to experiments show a good qualitative agreement, with increasing quantitative accuracy as the complexity of the underlying model increases. Air injection control of stall and surge is also investigated. Simultaneous control of stall and surge is achieved using axisymmetric air injection. Three cases with different injector back pressure are studied. Surge control via binary air injection is achieved in all three cases. Simultaneous stall and surge control is achieved for two of the cases, but is not achieved for the lowest authority case. This is consistent with previous results for control of stall with axisymmetric air injection without a plenum attached. Non-axisymmetric air injection control of stall and surge is also studied. Three existing control algorithms found in literature are modeled and analyzed. A three-state model is obtained for each algorithm. For two cases, conditions for linear stability and bifurcation criticality on control of rotating stall are

Resemblance profiles as clustering decision criteria: Estimating statistical power, error, and correspondence for a hypothesis test for multivariate structure.

Science.gov (United States)

Kilborn, Joshua P; Jones, David L; Peebles, Ernst B; Naar, David F

2017-04-01

Clustering data continues to be a highly active area of data analysis, and resemblance profiles are being incorporated into ecological methodologies as a hypothesis testing-based approach to clustering multivariate data. However, these new clustering techniques have not been rigorously tested to determine the performance variability based on the algorithm's assumptions or any underlying data structures. Here, we use simulation studies to estimate the statistical error rates for the hypothesis test for multivariate structure based on dissimilarity profiles (DISPROF). We concurrently tested a widely used algorithm that employs the unweighted pair group method with arithmetic mean (UPGMA) to estimate the proficiency of clustering with DISPROF as a decision criterion. We simulated unstructured multivariate data from different probability distributions with increasing numbers of objects and descriptors, and grouped data with increasing overlap, overdispersion for ecological data, and correlation among descriptors within groups. Using simulated data, we measured the resolution and correspondence of clustering solutions achieved by DISPROF with UPGMA against the reference grouping partitions used to simulate the structured test datasets. Our results highlight the dynamic interactions between dataset dimensionality, group overlap, and the properties of the descriptors within a group (i.e., overdispersion or correlation structure) that are relevant to resemblance profiles as a clustering criterion for multivariate data. These methods are particularly useful for multivariate ecological datasets that benefit from distance-based statistical analyses. We propose guidelines for using DISPROF as a clustering decision tool that will help future users avoid potential pitfalls during the application of methods and the interpretation of results.

Development of tooling suitable for stall regulated blades

Energy Technology Data Exchange (ETDEWEB)

Hancock, M.

2001-07-01

The objectives of the project were to make significant improvements in the production of stall regulated blades in the areas of (a) the tip box, its housing, its mechanism and small GRP parts; (b) mould technology; (c) resins and glues and (d) root tooling. Although wood composite had been identified as a competitive technology for blades, compared with GRP blades, production volumes had been lower; reasons are given. The way in which the four areas identified for investigation were tackled are discussed. The study showed that the mould cycle time can be reduced to two days for a stall regulated blade and the blade quality can be improved by using the composite tip box and new resins. The time required for replication of moulds can be reduced by 40%.

Internal Flow of a High Specific-Speed Diagonal-Flow Fan (Rotor Outlet Flow Fields with Rotating Stall

Directory of Open Access Journals (Sweden)

Norimasa Shiomi

2003-01-01

Full Text Available We carried out investigations for the purpose of clarifying the rotor outlet flow fields with rotating stall cell in a diagonal-flow fan. The test fan was a high–specific-speed (ns=1620 type of diagonal-flow fan that had 6 rotor blades and 11 stator blades. It has been shown that the number of the stall cell is 1, and its propagating speed is approximately 80% of its rotor speed, although little has been known about the behavior of the stall cell because a flow field with a rotating stall cell is essentially unsteady. In order to capture the behavior of the stall cell at the rotor outlet flow fields, hot-wire surveys were performed using a single-slant hotwire probe. The data obtained by these surveys were processed by means of a double phase-locked averaging technique, which enabled us to capture the flow field with the rotating stall cell in the reference coordinate system fixed to the rotor. As a result, time-dependent ensemble averages of the three-dimensional velocity components at the rotor outlet flow fields were obtained. The behavior of the stall cell was shown for each velocity component, and the flow patterns on the meridional planes were illustrated.

Conical Magnetic Bearings Developed for Active Stall Control in Gas Turbine Engines

Science.gov (United States)

Trudell, Jeffrey J.; Kascak, Albert F.; Provenza, Andrew J.; Buccieri, Carl J.

2004-01-01

Active stall control is a current research area at the NASA Glenn Research Center that offers a great benefit in specific fuel consumption by allowing the gas turbine to operate beyond the onset of stall. Magnetic bearings are being investigated as a new method to perform active stall control. This enabling global aviation safety technology would result in improved fuel efficiency and decreased carbon dioxide emissions, as well as improve safety and reliability by eliminating oil-related delays and failures of engine components, which account for 40 percent of the commercial aircraft departure delays. Active stall control works by perturbing the flow in front of the compressor stage such that it cancels the pressure wave, which causes the compressor to go into stall. Radial magnetic bearings are able to whirl the shaft so that variations in blade tip leakage would flow upstream causing a perturbation wave that could cancel the rotating stall cell. Axial or thrust magnetic bearings cannot be used to cancel the surge mode in the compressor because they have a very low bandwidth and thus cannot modulate at a high enough frequency. Frequency response is limited because the thrust runner cannot be laminated. To improve the bandwidth of magnetic thrust bearings, researchers must use laminations to suppress the eddy currents. A conical magnetic bearing can be laminated, resulting in increased bandwidth in the axial direction. In addition, this design can produce both radial and thrust force in a single bearing, simplifying the installation. The proposed solution combines the radial and thrust bearing into one design that can be laminated--a conical magnetic bearing. The new conical magnetic bearing test rig, funded by a Glenn fiscal year 2002 Director's Discretionary Fund, was needed because none of the existing rigs has an axial degree of freedom. The rotor bearing configuration will simulate that of the main shaft on a gas turbine engine. One conical magnetic bearing

A dynamic stall model for airfoils with deformable trailing edges

DEFF Research Database (Denmark)

Andersen, Peter Bjørn; Gaunaa, Mac; Bak, Dan Christian

2007-01-01

on an airfoil section undergoing arbitrary motion in heave, lead-lag, pitch, Trailing Edge (TE) flapping. In the linear region, the model reduces to the inviscid model of Gaunaa [4], which includes the aerodynamic effect of a thin airfoil with a deformable camberline in inviscid flow. Therefore, the proposed......The present work contains an extension of the Beddoes-Leishman (B-L) type dynamic stall model, as described by Hansen et al. [7]. In this work a Deformable Trailing Edge Geometry (DTEG) has been added to the dynamic stall model. The model predicts the unsteady aerodynamic forces and moments...

A time-varying subjective quality model for mobile streaming videos with stalling events

Science.gov (United States)

Ghadiyaram, Deepti; Pan, Janice; Bovik, Alan C.

2015-09-01

Over-the-top mobile video streaming is invariably influenced by volatile network conditions which cause playback interruptions (stalling events), thereby impairing users' quality of experience (QoE). Developing models that can accurately predict users' QoE could enable the more efficient design of quality-control protocols for video streaming networks that reduce network operational costs while still delivering high-quality video content to the customers. Existing objective models that predict QoE are based on global video features, such as the number of stall events and their lengths, and are trained and validated on a small pool of ad hoc video datasets, most of which are not publicly available. The model we propose in this work goes beyond previous models as it also accounts for the fundamental effect that a viewer's recent level of satisfaction or dissatisfaction has on their overall viewing experience. In other words, the proposed model accounts for and adapts to the recency, or hysteresis effect caused by a stall event in addition to accounting for the lengths, frequency of occurrence, and the positions of stall events - factors that interact in a complex way to affect a user's QoE. On the recently introduced LIVE-Avvasi Mobile Video Database, which consists of 180 distorted videos of varied content that are afflicted solely with over 25 unique realistic stalling events, we trained and validated our model to accurately predict the QoE, attaining standout QoE prediction performance.

Analysis of compressible light dynamic stall flow at transitional Reynolds numbers

DEFF Research Database (Denmark)

Dyken, R.D. Van; Ekaterinaris, John A.; Chandrasekhara, M.S.

1996-01-01

Numerical and experimental results of steady and light dynamic stall flow over an oscillating NACA 0012 airfoil at a freestream Mach number of 0.3 and Reynolds number of 0.54 x 10(6) are compared, The experimental observation that dynamic stall is induced from the bursting of a laminar separation...... point is specified suitably and a simple transition length model is incorporated to determine the extent of the laminar separation bubble. The thin-layer approximations of compressible, Reynolds-averaged, Navier-Stokes equations are used for the numerical solution, with an implicit, upwind-biased, third...

The computation of the post-stall behavior of a circulation controlled airfoil

Science.gov (United States)

Linton, Samuel W.

1993-01-01

The physics of the circulation controlled airfoil is complex and poorly understood, particularly with regards to jet stall, which is the eventual breakdown of lift augmentation by the jet at some sufficiently high blowing rate. The present paper describes the numerical simulation of stalled and unstalled flows over a two-dimensional circulation controlled airfoil using a fully implicit Navier-Stokes code, and the comparison with experimental results. Mach numbers of 0.3 and 0.5 and jet total to freestream pressure ratios of 1.4 and 1.8 are investigated. The Baldwin-Lomax and k-epsilon turbulence models are used, each modified to include the effect of strong streamline curvature. The numerical solutions of the post-stall circulation controlled airfoil show a highly regular unsteady periodic flowfield. This is the result of an alternation between adverse pressure gradient and shock induced separation of the boundary layer on the airfoil trailing edge.

Parametric analyses on dynamic stall control of rotor airfoil via synthetic jet

Directory of Open Access Journals (Sweden)

Qijun ZHAO

2017-12-01

Full Text Available The effects of synthetic jet control on unsteady dynamic stall over rotor airfoil are investigated numerically. A moving-embedded grid method and an Unsteady Reynolds Averaged Navier-Stokes (URANS solver coupled with k-ω Shear Stress Transport (SST turbulence model are established for predicting the complex flowfields of oscillatory airfoil under jet control. Additionally, a velocity boundary condition modeled by sinusoidal function has been developed to fulfill the perturbation effect of periodic jet. The validity of present CFD method is evaluated by comparisons of the calculated results of baseline dynamic stall case for rotor airfoil and jet control case for VR-7B airfoil with experimental data. Then, parametric analyses are conducted emphatically for an OA212 rotor airfoil to investigate the effects of jet control parameters (jet location, dimensionless frequency, momentum coefficient, jet angle, jet type and dual-jet on dynamic stall characteristics of rotor airfoil. It is demonstrated by the calculated results that efficiency of jet control could be improved with specific momentum coefficient and jet angle when the jet is located near separation point of rotor airfoil. Furthermore, the dual-jet could improve control efficiency more obviously on dynamic stall of rotor airfoil with respect to the unique jet, and the influence laws of dual-jet’s angles and momentum coefficients on control effects are similar to those of the unique jet. Finally, unsteady aerodynamic characteristics of rotor via synthetic jet which is located on the upper surface of rotor blade in forward flight are calculated, and as a result, the aerodynamic characteristics of rotor are improved compared with the baseline. The results indicate that synthetic jet has the capability in improving aerodynamic characteristics of rotor. Keywords: Airfoil, Dynamic stall characteristics, Flow control, Moving-embedded grid methodology, Navier-Stokes equations, Parametric

Time Accurate Unsteady Simulation of the Stall Inception Process in the Compression System of a US Army Helicopter Gas Turbine Engine

National Research Council Canada - National Science Library

Hathaway, Michael D; Herrick, Greg; Chen, Jenping; Webster, Robert

2004-01-01

.... Improved understanding of the stall inception process and how stall control technologies mitigate such will provide compressors with increased tolerance to stall, thereby expanding the operational...

Aerodynamic shape optimization for alleviating dynamic stall characteristics of helicopter rotor airfoil

Directory of Open Access Journals (Sweden)

Wang Qing

2015-04-01

Full Text Available In order to alleviate the dynamic stall effects in helicopter rotor, the sequential quadratic programming (SQP method is employed to optimize the characteristics of airfoil under dynamic stall conditions based on the SC1095 airfoil. The geometry of airfoil is parameterized by the class-shape-transformation (CST method, and the C-topology body-fitted mesh is then automatically generated around the airfoil by solving the Poisson equations. Based on the grid generation technology, the unsteady Reynolds-averaged Navier-Stokes (RANS equations are chosen as the governing equations for predicting airfoil flow field and the highly-efficient implicit scheme of lower–upper symmetric Gauss–Seidel (LU-SGS is adopted for temporal discretization. To capture the dynamic stall phenomenon of the rotor more accurately, the Spalart–Allmaras turbulence model is employed to close the RANS equations. The optimized airfoil with a larger leading edge radius and camber is obtained. The leading edge vortex and trailing edge separation of the optimized airfoil under unsteady conditions are obviously weakened, and the dynamic stall characteristics of optimized airfoil at different Mach numbers, reduced frequencies and angles of attack are also obviously improved compared with the baseline SC1095 airfoil. It is demonstrated that the optimized method is effective and the optimized airfoil is suitable as the helicopter rotor airfoil.

Discrimination of artificial categories structured by family resemblances: a comparative study in people (Homo sapiens) and pigeons (Columba livia).

Science.gov (United States)

Makino, Hiroshi; Jitsumori, Masako

2007-02-01

Adult humans (Homo sapiens) and pigeons (Columba livia) were trained to discriminate artificial categories that the authors created by mimicking 2 properties of natural categories. One was a family resemblance relationship: The highly variable exemplars, including those that did not have features in common, were structured by a similarity network with the features correlating to one another in each category. The other was a polymorphous rule: No single feature was essential for distinguishing the categories, and all the features overlapped between the categories. Pigeons learned the categories with ease and then showed a prototype effect in accord with the degrees of family resemblance for novel stimuli. Some evidence was also observed for interactive effects of learning of individual exemplars and feature frequencies. Humans had difficulty in learning the categories. The participants who learned the categories generally responded to novel stimuli in an all-or-none fashion on the basis of their acquired classification decision rules. The processes that underlie the classification performances of the 2 species are discussed.

Dynamic stall - The case of the vertical axis wind turbine

Science.gov (United States)

Laneville, A.; Vittecoq, P.

1986-05-01

This paper presents the results of an experimental investigation on a driven Darrieus turbine rotating at different tip speed ratios. For a Reynolds number of 3.8 x 10 to the 4th, the results indicate the presence of dynamic stall at tip speed ratio less than 4, and that helicopter blade aerodynamics can be used in order to explain some aspects of the phenomenon. It was observed that in deep stall conditions, a vortex is formed at the leading edge; this vortex moves over the airfoil surface with 1/3 of the airfoil speed and then is shed at the trailing edge. After its shedding, the vortex can interact with the airfoil surface as the blade passes downstream.

DYNSTALL: Subroutine package with a dynamic stall model

Energy Technology Data Exchange (ETDEWEB)

Bjoerck, Anders [Aeronautical Research Inst. of Sweden, Bromma (Sweden)

2001-03-01

A subroutine package, called DYNSTALL, for the calculation of 2D unsteady airfoil aerodynamics is described. The subroutines are written in FORTRAN. DYNSTALL is basically an implementation of the Beddoes-Leishman dynamic stall model. This model is a semi-empirical model for dynamic stall. It includes, however, also models for attached flow unsteady aerodynamics. It is complete in the sense that it treats attached flow as well as separated flow. Semi-empirical means that the model relies on empirically determined constants. Semi because the constants are constants in equations with some physical interpretation. It requires the input of 2D airfoil aerodynamic data via tables as function of angle of attack. The method is intended for use in an aeroelastic code with the aerodynamics solved by blade/element method. DYNSTALL was written to work for any 2D angles of attack relative to the airfoil, e.g. flow from the rear of an airfoil.

Dynamic Stall Vortex Formation of OA-209 Airfoil at Low Reynolds Number

OpenAIRE

Aung Myo Thu; Sang Eon Jeon; Yung Hwan Byun; Soo Hyung Park

2014-01-01

The unsteady flow field around oscillating OA-209 airfoil at a Reynolds number of 3.5×105 were investigated. Three different reduced frequencies were tested in order to see how it affects the hysteresis loop of an airfoil. At a reduced frequency of 0.05 the deep dynamic stall phenomenon was observed. Lift overshooting was observed as a result of dynamic stall vortex (DSV) shedding. Further investigation was carried out to find out the cause of DSV formation and shedding over airfoil. Particle...

Flight Measurements of the Flying Qualities of a Lockheed P-80A Airplane (Army No. 44-85099) - Stalling Characteristics

Science.gov (United States)

Anderson, Seth B.; Cooper, George E.

1947-01-01

This report contains the flight-test results of the stalling characteristics measured during the flying-qualities investigation of the Lockheed P-8OA airplane (Army No. 44-85099). The tests were conducted in straight and turning flight with and without wing-tip tanks. These tests showed satisfactory stalling characteristics and adequate stall warning for all configurations and conditions tested.

Diagnosis of voltage collapse due to induction motor stalling using static analysis

International Nuclear Information System (INIS)

Karbalaei, F.; Kalantar, M.; Kazemi, A.

2008-01-01

Induction motor stalling is one of the important reasons for voltage collapse. This paper presents that, for induction motor stalling diagnosis, it is not necessary to use a third or first order dynamic model of induction motors. Instead, a method is presented based on algebraic calculations for which the steady state model of the induction motor considering different kinds of mechanical loads (constant and variable torque) is added to the power flow equations. Simulation results for a simple system confirm the correctness of the proposed method as compared to dynamic simulation results

Piloted Simulator Evaluation Results of Flight Physics Based Stall Recovery Guidance

Science.gov (United States)

Lombaerts, Thomas; Schuet, Stefan; Stepanyan, Vahram; Kaneshige, John; Hardy, Gordon; Shish, Kimberlee; Robinson, Peter

2018-01-01

In recent studies, it has been observed that loss of control in flight is the most frequent primary cause of accidents. A significant share of accidents in this category can be remedied by upset prevention if possible, and by upset recovery if necessary, in this order of priorities. One of the most important upsets to be recovered from is stall. Recent accidents have shown that a correct stall recovery maneuver remains a big challenge in civil aviation, partly due to a lack of pilot training. A possible strategy to support the flight crew in this demanding context is calculating a recovery guidance signal, and showing this signal in an intuitive way on one of the cockpit displays, for example by means of the flight director. Different methods for calculating the recovery signal, one based on fast model predictive control and another using an energy based approach, have been evaluated in four relevant operational scenarios by experienced commercial as well as test pilots in the Vertical Motion Simulator at NASA Ames Research Center. Evaluation results show that this approach could be able to assist the pilots in executing a correct stall recovery maneuver.

An experimental description of the flow in a centrifugal compressor from alternate stall to surge

Science.gov (United States)

Moënne-Loccoz, V.; Trébinjac, I.; Benichou, E.; Goguey, S.; Paoletti, B.; Laucher, P.

2017-08-01

The present paper gives the experimental results obtained in a centrifugal compressor stage designed and built by SAFRAN Helicopter Engines. The compressor is composed of inlet guide vanes, a backswept splittered unshrouded impeller, a splittered vaned radial diffuser and axial outlet guide vanes. Previous numerical simulations revealed a particular S-shape pressure rise characteristic at partial rotation speed and predicted an alternate flow pattern in the vaned radial diffuser at low mass flow rate. This alternate flow pattern involves two adjacent vane passages. One passage exhibits very low momentum and a low pressure recovery, whereas the adjacent passage has very high momentum in the passage inlet and diffuses efficiently. Experimental measurements confirm the S-shape of the pressure rise characteristic even if the stability limit experimentally occurs at higher mass flow than numerically predicted. At low mass flow the alternate stall pattern is confirmed thanks to the data obtained by high-frequency pressure sensors. As the compressor is throttled the path to instability has been registered and a first scenario of the surge inception is given. The compressor first experiences a steady alternate stall in the diffuser. As the mass flow decreases, the alternate stall amplifies and triggers the mild surge in the vaned diffuser. An unsteady behavior results from the interaction of the alternate stall and the mild surge. Finally, when the pressure gradient becomes too strong, the alternate stall blows away and the compressor enters into deep surge.

The FFA dynamic stall model. The Beddoes-Leishman dynamic stall model modified for lead-lag oscillations

Energy Technology Data Exchange (ETDEWEB)

Bjoerck, A. [FFA, The Aeronautical Research Institute of Sweden, Bromma (Sweden)

1997-08-01

For calculations of the dynamics of wind turbines the inclusion of a dynamic stall model is necessary in order to obtain reliable results at high winds. For blade vibrations in the lead-lag motion the velocity relative to the blade will vary in time. In the present paper modifications to the Beddoes-Leishman model is presented in order to improve the model for calculations of cases with a varying relative velocity. Comparisons with measurement are also shown and the influence on the calculated aerodynamic damping by the modifications are investigated. (au)

Stalled replication forks generate a distinct mutational signature in yeast

DEFF Research Database (Denmark)

Larsen, Nicolai B.; Liberti, Sascha E.; Vogel, Ivan

2017-01-01

Proliferating cells acquire genome alterations during the act of DNA replication. This leads to mutation accumulation and somatic cell mosaicism in multicellular organisms, and is also implicated as an underlying cause of aging and tumorigenesis. The molecular mechanisms of DNA replication...... Escherichia coli Tus/Ter complex) engineered into the yeast genome. We demonstrate that transient stalling at this barrier induces a distinct pattern of genome rearrangements in the newly replicated region behind the stalled fork, which primarily consist of localized losses and duplications of DNA sequences....... These genetic alterations arise through the aberrant repair of a single-stranded DNA gap, in a process that is dependent on Exo1- and Shu1-dependent homologous recombination repair (HRR). Furthermore, aberrant processing of HRR intermediates, and elevated HRR-associated mutagenesis, is detectable in a yeast...

A Dynamic Stall Model for Airfoils with Deformable Trailing Edges

International Nuclear Information System (INIS)

Andersen, Peter Bjoern; Gaunaa, Mac; Bak, Christian; Hansen, Morten Hartvig

2007-01-01

The present work contains an extension of the Beddoes-Leishman (B-L) type dynamic stall model, as described by Hansen et al. In this work a Deformable Trailing Edge Geometry (DTEG) has been added to the dynamic stall model. The model predicts the unsteady aerodynamic forces and moments on an airfoil section undergoing arbitrary motion in heave, lead-lag, pitch, Trailing Edge (TE) flapping. In the linear region, the model reduces to the inviscid model of Gaunaa, which includes the aerodynamic effect of a thin airfoil with a deformable camberline in inviscid flow. Therefore, the proposed model can be considered a crossover between the work of Gaunaa for the attached flow region and Hansen et al. The model will be compared to wind tunnel measurements from Velux described by Bak et al

An insight into the separate flow and stall delay for HAWT

Energy Technology Data Exchange (ETDEWEB)

Yu, Guohua; Shen, Xin; Zhu, Xiaocheng; Du, Zhaohui [School of Mechanical Engineering, Shanghai Jiao Tong University, Shanghai 200240 (China)

2011-01-15

The flow characteristics and the stall delay phenomenon of wind turbine rotor due to blade rotation in the steady state non-yawed conditions are investigated. An incompressible Reynolds-averaged Navier-Stokes solver is applied to carry out all the cases at different wind speeds from 5 m/s to 10 m/s with an interval of 1 m/s. CFD results turn out to agree well with experimental ones at incoming wind speeds below 10 m/s, though at 10 m/s some deviations exist due to the relative large flow separation and 3D spanwise flow over the suction surface of the blade. In the meanwhile, a lifting surface code with and without Du-Selig stall delay model is used to predict the power. A MATLAB code is developed to extract aerodynamic force coefficients from 3D CFD computations which are compared with the 2D airfoil wind tunnel experiment to demonstrate the stall delay and augmented lift phenomenon particularly at inboard span locations of the blade. The computational results are compared with the corrected value by the Du-Selig model and a lifting surface method derived data based on the measurements of the Unsteady Aerodynamic Experiment at the NASA Ames wind tunnel. (author)

Effect of stall design on dairy calf transition to voluntary feeding on an automatic milk feeder after introduction to group housing.

Science.gov (United States)

Wilson, Tanya R; LeBlanc, Stephen J; DeVries, Trevor J; Haley, Derek B

2018-06-01

Automatic milk feeders (AMF) for young dairy calves are widely used in the dairy industry. These feeders are thought to have benefits for calf health and welfare and may reduce labor required for feeding; however, little is known about how calves adapt to feeding with AMF. The objective of this study was to observe the effects of feeding stall design on calves learning to use the AMF. The hypothesis was that solid side stalls, compared with steel bar stalls, would result in a longer latency to approach and feed from the AMF without assistance. A total of 147 Holstein calves (80 male and 67 female) were enrolled at 4 d of age, introduced to a group pen, and, at the same time, trained on an AMF. For training, calves were allowed to suck on the trainer's fingers and guided to the teat. Calves were allocated to 1 of 2 stall designs at the pen level, depending on which treatment cohort they were born into, either with steel bar stall walls (n = 46 male, 34 female calves) or with solid side stall walls (n = 34 male, 33 female calves). For 72 h after introductory training on the AMF, data from the feeders were collected and calf behavior was monitored by video. Outcomes measured included latency to first voluntary visit to the feeder and to first feeding, time spent in the feeder, amount of milk consumed over 72 h, number of retraining sessions required (retrained if linear regression models or a Poisson model for the outcome of retraining. For certain outcomes the effects of stall design interacted with difficulty of training (willingness to enter feeder and drink); for the 38% of calves that were scored as moderately difficult to train on a scale of easy, moderate, or difficult, treatment (stall design) differences were detected. These calves took 2× longer to lick or bite toward the nipple, 2× longer to first voluntarily feeding, and consumed less milk over 72 h following training when trained on the steel bar stall design. These results suggest simple features of a

Effect of free stall surface on daily activity patterns in dairy cows with relevance to lameness prevalence.

Science.gov (United States)

Cook, N B; Bennett, T B; Nordlund, K V

2004-09-01

Differences in behavior of nonlame cows, slightly lame cows, and moderately lame cows in 6 free stall barns with sand bedding (SAND) vs. 6 free stall barns with rubber-crumb geotextile mattress surfaces (MAT) were documented in Wisconsin dairy herds. All lactating cows in the 12 herds were observed and given a locomotion score based on a 4-point scale: 1 = nonlame, 2 = slightly lame, 3 = moderately lame, and 4 = severely lame. Herd least square means +/-SE for prevalence of clinical lameness (locomotion scores = 3 and 4) were 11.1 vs. 24.0 +/- 1.7% for herds using SAND vs. MAT surfaces, respectively. Subsets of 10 cows per herd with locomotion scores of 1 to 3 were observed via video cameras for 24-h periods. Cows in MAT herds spent more time standing in free stalls per day than cows in SAND herds. Differences in standing times were 0.73 h/d for cows that were not lame, 2.32 h/d for cows that were slightly lame, and 4.31 h/d for cows that were moderately lame in MAT herds compared with equivalent cows in SAND herds. In MAT herds, the increase in time spent standing in the stall in moderately lame cows was associated with a significant reduction in stall use sessions per day, which impacted daily lying time. Although cause and effect are not clear, these findings have implications for housing, comfort, and care of cows in dairy herds with different types of free stall surfaces.

Prediction of rotating stall within an impeller of a centrifugal pump based on spectral analysis of pressure and velocity data

International Nuclear Information System (INIS)

Ullum, Ulrik; Wright, Jennifer; Dayi, Oguz; Ecder, Ali; Soulaimani, Azzeddine; Piche, Robert; Kamath, Hemant

2006-01-01

Experimental data, which was acquired in two centrifugal pumps and provided by Grundfos A/S, were analysed to determine if rotating stall could be detected from the velocity and pressure time series. The pressure data, which were uniformly acquired in time at high sample rates(10 kHz), were measured simultaneously in four adjacent di.user channels just downstream of the impeller outlet. The velocity data, which were non-uniformly sampled in time at fairly low rates(100 Hz to 3.5 kHz), were acquired either in or downstream of the impeller. Two di.erent methodologies were employed for detection of stall. The first method, which involved direct analysis of raw data, yielded qualitatively useful flow reversal information from the time series for the radial velocity. The second approach, which was based on power spectrum analysis of velocity and pressure data, could detect the onset and identify the frequency of rotating stall to a satisfactory extent in one of the two pumps. Nearly identical stall frequencies were observed in both velocity and pressure power spectra and this rotating stall phenomenon, which occurred at a very low frequency relative to the impeller speed, did not reveal any noticeable degree of sensitivity to the flow rate. In the other pump, where the available data was limited to velocity time series, the power spectrum analysis was successful in detecting stationary stall for a 6 bladed impeller but did not provide conclusive results for the existence of stall in the case of the 7 bladed impeller. Recommendations on the type of experimental data required for accurate detection of stall are provided based upon the present study

Airborne Microorganisms in Tie-stall Dairy Barns from Brasov County

Directory of Open Access Journals (Sweden)

Silvana Popescu

2011-05-01

Full Text Available The aim of this study was the assessment of the airborne microorganisms in tie-stall dairy cattle barns, through determination of the total number of bacteria (mesophilic bacteria, staphylococci, streptococci and gram-negative bacteria and fungi. We investigated 8 dairy cattle barns with tie-stalls in Brasov County during the winter of 2009. The mean numbers of bacteria and fungi in the morning and in the evening were: 1.02 °— 105 - 1.26 °— 105 CFU/m3 for mesophilic bacteria, 5.34 °— 104 - 5.91 °— 104 CFU/m3 for staphylococci, 2.93 °— 104 - 3.60 °— 104 CFU/m3 for streptococci, 2.17 °— 103 - 3.48 °— 103 CFU/m3 for gram-negative bacteria and 1.54 °— 104 - 2.75 °— 104 CFU/m3 for fungi. In the investigated cattle houses staphylococci represented 52.35 – 46.90%, streptococci were 28.73 – 28.57%, and the gram-negative bacteria were 2.13 – 2.76% within the overall number of mesophilic bacteria. The numbers of bacteria and fungi were slightly elevated in the evening comparative to the morning, but the differences were statistically insignificant (p>0.05. The great numbers of bacteria and fungi in the air of dairy cattle tie-stall barns indicate an elevated risk of disease for animals and human workers.

A dynamic stall model for airfoils with deformable trailing edges

DEFF Research Database (Denmark)

Andersen, Peter Bjørn; Gaunaa, Mac; Bak, Christian

2009-01-01

, lead-lag, pitch, trailing-edge flapping. In the linear region, the model reduces to the inviscid model, which includes the aerodynamic effect of a thin airfoil with a deformable camberline in inviscid flow. Therefore, the proposed model can be considered a crossover between the work of Gaunaa......The present work contains an extension of the Beddoes-Leishman-type dynamic stall model. In this work, a deformable trailing-edge flap has been added to the dynamic stall model. The model predicts the unsteady aerodynamic forces and moments on an airfoil section undergoing arbitrary motion in heave...... for the attached flow region and Hansen et al. The model is compared qualitatively to wind tunnel measurements of a Riso/ B1-18 blade section equipped with deformable trailing-edge flap devices in the form of piezoelectric devices. Copyright © 2009 John Wiley & Sons, Ltd....

Simulating Dynamic Stall Effects for Vertical Axis Wind Turbines Applying a Double Multiple Streamtube Model

Directory of Open Access Journals (Sweden)

Eduard Dyachuk

2015-02-01

Full Text Available The complex unsteady aerodynamics of vertical axis wind turbines (VAWT poses significant challenges to the simulation tools. Dynamic stall is one of the phenomena associated with the unsteady conditions for VAWTs, and it is in the focus of the study. Two dynamic stall models are compared: the widely-used Gormont model and a Leishman–Beddoes-type model. The models are included in a double multiple streamtube model. The effects of flow curvature and flow expansion are also considered. The model results are assessed against the measured data on a Darrieus turbine with curved blades. To study the dynamic stall effects, the comparison of force coefficients between the simulations and experiments is done at low tip speed ratios. Simulations show that the Leishman–Beddoes model outperforms the Gormont model for all tested conditions.

Compressible dynamic stall vorticity flux control using a dynamic ...

Indian Academy of Sciences (India)

systems, such as a wind turbine, are prevented from ever entering dynamic stall, essentially disregarding potential ... future generations of such systems, an overwhelming need has developed to avail this benefit safely. ... approach must diffuse the vorticity prior to its coalescence, but keep the vorticity over the airfoil up to ...

DNA replication: stalling a fork for imprinting and switching

DEFF Research Database (Denmark)

Egel, Richard

2004-01-01

Mating-type switching in fission yeast has long been known to be directed by a DNA 'imprint'. This imprint has now been firmly characterized as a protected site-specific and strand-specific nick. New work also links the widely conserved Swi1-Swi3 complex to the protection of stalled replication...

Band-pass filtering algorithms for adaptive control of compressor pre-stall modes in aircraft gas-turbine engine

Science.gov (United States)

Kuznetsova, T. A.

2018-05-01

The methods for increasing gas-turbine aircraft engines' (GTE) adaptive properties to interference based on empowerment of automatic control systems (ACS) are analyzed. The flow pulsation in suction and a discharge line of the compressor, which may cause the stall, are considered as the interference. The algorithmic solution to the problem of GTE pre-stall modes’ control adapted to stability boundary is proposed. The aim of the study is to develop the band-pass filtering algorithms to provide the detection functions of the compressor pre-stall modes for ACS GTE. The characteristic feature of pre-stall effect is the increase of pressure pulsation amplitude over the impeller at the multiples of the rotor’ frequencies. The used method is based on a band-pass filter combining low-pass and high-pass digital filters. The impulse response of the high-pass filter is determined through a known low-pass filter impulse response by spectral inversion. The resulting transfer function of the second order band-pass filter (BPF) corresponds to a stable system. The two circuit implementations of BPF are synthesized. Designed band-pass filtering algorithms were tested in MATLAB environment. Comparative analysis of amplitude-frequency response of proposed implementation allows choosing the BPF scheme providing the best quality of filtration. The BPF reaction to the periodic sinusoidal signal, simulating the experimentally obtained pressure pulsation function in the pre-stall mode, was considered. The results of model experiment demonstrated the effectiveness of applying band-pass filtering algorithms as part of ACS to identify the pre-stall mode of the compressor for detection of pressure fluctuations’ peaks, characterizing the compressor’s approach to the stability boundary.

Accounting for biases in riboprofiling data indicates a major role for proline in stalling translation.

Science.gov (United States)

Artieri, Carlo G; Fraser, Hunter B

2014-12-01

The recent advent of ribosome profiling-sequencing of short ribosome-bound fragments of mRNA-has offered an unprecedented opportunity to interrogate the sequence features responsible for modulating translational rates. Nevertheless, numerous analyses of the first riboprofiling data set have produced equivocal and often incompatible results. Here we analyze three independent yeast riboprofiling data sets, including two with much higher coverage than previously available, and find that all three show substantial technical sequence biases that confound interpretations of ribosomal occupancy. After accounting for these biases, we find no effect of previously implicated factors on ribosomal pausing. Rather, we find that incorporation of proline, whose unique side-chain stalls peptide synthesis in vitro, also slows the ribosome in vivo. We also reanalyze a method that implicated positively charged amino acids as the major determinant of ribosomal stalling and demonstrate that it produces false signals of stalling in low-coverage data. Our results suggest that any analysis of riboprofiling data should account for sequencing biases and sparse coverage. To this end, we establish a robust methodology that enables analysis of ribosome profiling data without prior assumptions regarding which positions spanned by the ribosome cause stalling. © 2014 Artieri and Fraser; Published by Cold Spring Harbor Laboratory Press.

Active flow control of the laminar separation bubble on a plunging airfoil near stall

Science.gov (United States)

Pande, Arth; Agate, Mark; Little, Jesse; Fasel, Hermann

2017-11-01

The effects of small amplitude (A/c = 0.048) high frequency (πfc/U∞ = 0.70) plunging motion on the X-56A airfoil are examined experimentally at Re = 200,000 for 12° angle of attack (CL,MAX = 12.25°) . The purpose of this research is to study the aerodynamic influence of structural motion when the wing is vibrating close to its eigenfrequency near static stall. Specific focus is placed on the laminar separation bubble (LSB) near the leading edge and its control via plasma actuation. In the baseline case, the leading edge bubble bursts during the oscillation cycle causing moment stall. A collaborative computational effort has shown that small amplitude forcing at a frequency that is most amplified by the primary instability of the LSB (FLSB+= 1, Fc+= 52) generates coherent spanwise vortices that entrain freestream momentum, thus reducing separation all while maintaining a laminar flow state. Results (PIV and surface pressure) indicate that a similar control mechanism is effective in the experiments. This is significant given the existence of freestream turbulence in the wind tunnel which has been shown to limit the efficacy of this active flow control technique in a model problem using Direct Numerical Simulation. The implications of these results are discussed.

The influence of elevated feed stalls on feeding behaviour of lactating dairy cows

Directory of Open Access Journals (Sweden)

Barbara Benz

2014-10-01

Full Text Available The performance level of high yielding cows can only be guaranteed by high quality forage and high feed intake. An about 15–20 cm elevated and 160 cm long feed stall with rubber flooring doesn’t only offer undisturbed meals but also a yielding and dry standing surface. In a pilot stable with 130 dairy cows (German Simmental the feeding alley was subsequently equipped with elevated feed stalls. The results show that animals frequented the feeding barn less often while the duration of single meals prolonged. The specific behavioural changes differed depending on milk yield and number of lactation.

A kinesthetic-tactual display for stall deterrence

Science.gov (United States)

Gilson, R. D.; Ventola, R. W.; Fenton, R. E.

1975-01-01

A kinesthetic tactual display may be effectively used as a control aid per previous flight tests. Angle of attack information would be continuously presented to a pilot, via this display, during critical operational phases where stalls are probable. A two phase plan for evaluating this concept is presented. A first development phase would encompass: (1) display fabrication for a conventional control yoke; (2) its installation, together with other necessary instrumentation, in an experimental aircraft; and (3) preliminary flight testing by experienced pilots.

Design of advanced airfoil for stall-regulated wind turbines

Directory of Open Access Journals (Sweden)

F. Grasso

2017-07-01

Full Text Available Nowadays, all the modern megawatt-class wind turbines make use of pitch control to optimise the rotor performance and control the turbine. However, for kilowatt-range machines, stall-regulated solutions are still attractive and largely used for their simplicity and robustness. In the design phase, the aerodynamics plays a crucial role, especially concerning the selection/design of the necessary airfoils. This is because the airfoil performance is supposed to guarantee high wind turbine performance but also the necessary machine control capabilities. In the present work, the design of a new airfoil dedicated to stall machines is discussed. The design strategy makes use of a numerical optimisation scheme, where a gradient-based algorithm is coupled with the RFOIL code and an original Bezier-curves-based parameterisation to describe the airfoil shape. The performances of the new airfoil are compared in free- and fixed-transition conditions. In addition, the performance of the rotor is analysed, comparing the impact of the new geometry with alternative candidates. The results show that the new airfoil offers better performance and control than existing candidates do.

High-resolution LES of the rotating stall in a reduced scale model pump-turbine

International Nuclear Information System (INIS)

Pacot, Olivier; Avellan, François; Kato, Chisachi

2014-01-01

Extending the operating range of modern pump-turbines becomes increasingly important in the course of the integration of renewable energy sources in the existing power grid. However, at partial load condition in pumping mode, the occurrence of rotating stall is critical to the operational safety of the machine and on the grid stability. The understanding of the mechanisms behind this flow phenomenon yet remains vague and incomplete. Past numerical simulations using a RANS approach often led to inconclusive results concerning the physical background. For the first time, the rotating stall is investigated by performing a large scale LES calculation on the HYDRODYNA pump-turbine scale model featuring approximately 100 million elements. The computations were performed on the PRIMEHPC FX10 of the University of Tokyo using the overset Finite Element open source code FrontFlow/blue with the dynamic Smagorinsky turbulence model and the no-slip wall condition. The internal flow computed is the one when operating the pump-turbine at 76% of the best efficiency point in pumping mode, as previous experimental research showed the presence of four rotating cells. The rotating stall phenomenon is accurately reproduced for a reduced Reynolds number using the LES approach with acceptable computing resources. The results show an excellent agreement with available experimental data from the reduced scale model testing at the EPFL Laboratory for Hydraulic Machines. The number of stall cells as well as the propagation speed corroborates the experiment

High-resolution LES of the rotating stall in a reduced scale model pump-turbine

Science.gov (United States)

Pacot, Olivier; Kato, Chisachi; Avellan, François

2014-03-01

Extending the operating range of modern pump-turbines becomes increasingly important in the course of the integration of renewable energy sources in the existing power grid. However, at partial load condition in pumping mode, the occurrence of rotating stall is critical to the operational safety of the machine and on the grid stability. The understanding of the mechanisms behind this flow phenomenon yet remains vague and incomplete. Past numerical simulations using a RANS approach often led to inconclusive results concerning the physical background. For the first time, the rotating stall is investigated by performing a large scale LES calculation on the HYDRODYNA pump-turbine scale model featuring approximately 100 million elements. The computations were performed on the PRIMEHPC FX10 of the University of Tokyo using the overset Finite Element open source code FrontFlow/blue with the dynamic Smagorinsky turbulence model and the no-slip wall condition. The internal flow computed is the one when operating the pump-turbine at 76% of the best efficiency point in pumping mode, as previous experimental research showed the presence of four rotating cells. The rotating stall phenomenon is accurately reproduced for a reduced Reynolds number using the LES approach with acceptable computing resources. The results show an excellent agreement with available experimental data from the reduced scale model testing at the EPFL Laboratory for Hydraulic Machines. The number of stall cells as well as the propagation speed corroborates the experiment.

Modelling of multiple short-length-scale stall cells in an axial compressor using evolved GMDH neural networks

International Nuclear Information System (INIS)

Amanifard, N.; Nariman-Zadeh, N.; Farahani, M.H.; Khalkhali, A.

2008-01-01

Over the past 15 years there have been several research efforts to capture the stall inception nature in axial flow compressors. However previous analytical models could not explain the formation of short-length-scale stall cells. This paper provides a new model based on evolved GMDH neural network for transient evolution of multiple short-length-scale stall cells in an axial compressor. Genetic Algorithms (GAs) are also employed for optimal design of connectivity configuration of such GMDH-type neural networks. In this way, low-pass filter (LPF) pressure trace near the rotor leading edge is modelled with respect to the variation of pressure coefficient, flow rate coefficient, and number of rotor rotations which are defined as inputs

Dynamics and Control of Three-Dimensional Perching Maneuver under Dynamic Stall Influence

Science.gov (United States)

Feroskhan, Mir Alikhan Bin Mohammad

Perching is a type of aggressive maneuver performed by the class 'Aves' species to attain precision point landing with a generally short landing distance. Perching capability is desirable on unmanned aerial vehicles (UAVs) due to its efficient deceleration process that potentially expands the functionality and flight envelope of the aircraft. This dissertation extends the previous works on perching, which is mostly limited to two-dimensional (2D) cases, to its state-of-the-art threedimensional (3D) variety. This dissertation presents the aerodynamic modeling and optimization framework adopted to generate unprecedented variants of the 3D perching maneuver that include the sideslip perching trajectory, which ameliorates the existing 2D perching concept by eliminating the undesirable undershoot and reliance on gravity. The sideslip perching technique methodically utilizes the lateral and longitudinal drag mechanisms through consecutive phases of yawing and pitching-up motion. Since perching maneuver involves high rates of change in the angles of attack and large turn rates, introduction of three internal variables thus becomes necessary for addressing the influence of dynamic stall delay on the UAV's transient post-stall behavior. These variables are then integrated into a static nonlinear aerodynamic model, developed using empirical and analytical methods, and into an optimization framework that generates a trajectory of sideslip perching maneuver, acquiring over 70% velocity reduction. An impact study of the dynamic stall influence on the optimal perching trajectories suggests that consideration of dynamic stall delay is essential due to the significant discrepancies in the corresponding control inputs required. A comparative study between 2D and 3D perching is also conducted to examine the different drag mechanisms employed by 2D and 3D perching respectively. 3D perching is presented as a more efficient deceleration technique with respect to spatial costs and

A model for the selective amplification of spatially coherent waves in a centrifugal compressor on the verge of rotating stall

Science.gov (United States)

Lawless, Patrick B.; Fleeter, Sanford

1993-01-01

A simple model for the stability zones of a low speed centrifugal compressor is developed, with the goal of understanding the driving mechanism for the changes in stalling behavior predicted for, and observed in, the Purdue Low Speed Centrifugal Research Compressor Facility. To this end, earlier analyses of rotating stall suppression in centrifugal compressors are presented in a reduced form that preserves the essential parameters of the model that affect the stalling behavior of the compressor. The model is then used to illuminate the relationship between compressor geometry, expected mode shape, and regions of amplification for weak waves which are indicative of the susceptibility of the system to rotating stall. The results demonstrate that increasing the stagger angle of the diffuser vanes, and consequently the diffusion path length, results in the compressor moving towards a condition where higher-order spatial modes are excited during stall initiation. Similarly, flow acceleration in the diffuser section caused by an increase in the number of diffuser vanes also results in the excitation of higher modes.

Power reduction and the radial limit of stall delay in revolving wings of different aspect ratio.

Science.gov (United States)

Kruyt, Jan W; van Heijst, GertJan F; Altshuler, Douglas L; Lentink, David

2015-04-06

Airplanes and helicopters use high aspect ratio wings to reduce the power required to fly, but must operate at low angle of attack to prevent flow separation and stall. Animals capable of slow sustained flight, such as hummingbirds, have low aspect ratio wings and flap their wings at high angle of attack without stalling. Instead, they generate an attached vortex along the leading edge of the wing that elevates lift. Previous studies have demonstrated that this vortex and high lift can be reproduced by revolving the animal wing at the same angle of attack. How do flapping and revolving animal wings delay stall and reduce power? It has been hypothesized that stall delay derives from having a short radial distance between the shoulder joint and wing tip, measured in chord lengths. This non-dimensional measure of wing length represents the relative magnitude of inertial forces versus rotational accelerations operating in the boundary layer of revolving and flapping wings. Here we show for a suite of aspect ratios, which represent both animal and aircraft wings, that the attachment of the leading edge vortex on a revolving wing is determined by wing aspect ratio, defined with respect to the centre of revolution. At high angle of attack, the vortex remains attached when the local radius is shorter than four chord lengths and separates outboard on higher aspect ratio wings. This radial stall limit explains why revolving high aspect ratio wings (of helicopters) require less power compared with low aspect ratio wings (of hummingbirds) at low angle of attack and vice versa at high angle of attack. © 2015 The Author(s) Published by the Royal Society. All rights reserved.

Unsteady behavior of leading-edge vortex and diffuser stall in a centrifugal compressor with vaned diffuser

Science.gov (United States)

Fujisawa, Nobumichi; Hara, Shotaro; Ohta, Yutaka

2016-02-01

The characteristics of a rotating stall of an impeller and diffuser and the evolution of a vortex generated at the diffuser leading-edge (i.e., the leading-edge vortex (LEV)) in a centrifugal compressor were investigated by experiments and numerical analysis. The results of the experiments revealed that both the impeller and diffuser rotating stalls occurred at 55 and 25 Hz during off-design flow operation. For both, stall cells existed only on the shroud side of the flow passages, which is very close to the source location of the LEV. According to the CFD results, the LEV is made up of multiple vortices. The LEV is a combination of a separated vortex near the leading- edge and a longitudinal vortex generated by the extended tip-leakage flow from the impeller. Therefore, the LEV is generated by the accumulation of vorticity caused by the velocity gradient of the impeller discharge flow. In partial-flow operation, the spanwise extent and the position of the LEV origin are temporarily transmuted. The LEV develops with a drop in the velocity in the diffuser passage and forms a significant blockage within the diffuser passage. Therefore, the LEV may be regarded as being one of the causes of a diffuser stall in a centrifugal compressor.

[Liesegang's rings resembling helminthiasis].

Science.gov (United States)

Zámecník, M; Riedl, I

1996-12-01

So called Liesegang's rings are lamellar corpuscles which develop after periodical precipitation of oversaturated solutions in gel medium. They can occur in cysts, closed cavities, inflammatory exudates and necroses. They resemble parasitic eggs, larvae or adult forms. A case of 28-year-old woman is presented with many Liesegang's rings in a stuff from dilated renal calyx. Their preliminary evaluation considered helminths, especially Dioctophyma renale.

Study of Near-Stall Flow Behavior in a Modern Transonic Fan with Composite Sweep

Science.gov (United States)

Hah, Chunill; Shin, Hyoun-Woo

2011-01-01

Detailed flow behavior in a modern transonic fan with a composite sweep is investigated in this paper. Both unsteady Reynolds-averaged Navier-Stokes (URANS) and Large Eddy Simulation (LES) methods are applied to investigate the flow field over a wide operating range. The calculated flow fields are compared with the data from an array of high-frequency response pressure transducers embedded in the fan casing. The current study shows that a relatively fine computational grid is required to resolve the flow field adequately and to calculate the pressure rise across the fan correctly. The calculated flow field shows detailed flow structure near the fan rotor tip region. Due to the introduction of composite sweep toward the rotor tip, the flow structure at the rotor tip is much more stable compared to that of the conventional blade design. The passage shock stays very close to the leading edge at the rotor tip even at the throttle limit. On the other hand, the passage shock becomes stronger and detaches earlier from the blade passage at the radius where the blade sweep is in the opposite direction. The interaction between the tip clearance vortex and the passage shock becomes intense as the fan operates toward the stall limit, and tip clearance vortex breakdown occurs at near-stall operation. URANS calculates the time-averaged flow field fairly well. Details of measured RMS static pressure are not calculated with sufficient accuracy with URANS. On the other hand, LES calculates details of the measured unsteady flow features in the current transonic fan with composite sweep fairly well and reveals the flow mechanism behind the measured unsteady flow field.

A flight investigation of the ultra-deep-stall descent and spin recovery characteristics of a 1/6 scale radiocontrolled model of the Piper PA38 Tomahawk

Science.gov (United States)

Blanchard, W. S., Jr.

1981-01-01

Ultradeep stall descent and spin recovery characteristics of a 1/6 scale radio controlled model of the Piper PA38 Tomahawk aircraft was investigated. It was shown that the full scale PA38 is a suitable aircraft for conducting ultradeep stall research. Spin recovery was accomplished satisfactorily by entry to the ultradeep stall mode, followed by the exit from the ultradeep stall mode. It is concluded that since the PA38 has excellent spin recovery characteristics using normal recovery techniques (opposite rudder and forward control colum pressure), recovery using ultradeep stall would be beneficial only if the pilot suffered from disorientation.

Robust post-stall perching with a simple fixed-wing glider using LQR-Trees

International Nuclear Information System (INIS)

Moore, Joseph; Cory, Rick; Tedrake, Russ

2014-01-01

Birds routinely execute post-stall maneuvers with a speed and precision far beyond the capabilities of our best aircraft control systems. One remarkable example is a bird exploiting post-stall pressure drag in order to rapidly decelerate to land on a perch. Stall is typically associated with a loss of control authority, and it is tempting to attribute this agility of birds to the intricate morphology of the wings and tail, to their precision sensing apparatus, or their ability to perform thrust vectoring. Here we ask whether an extremely simple fixed-wing glider (no propeller) with only a single actuator in the tail is capable of landing precisely on a perch from a large range of initial conditions. To answer this question, we focus on the design of the flight control system; building upon previous work which used linear feedback control design based on quadratic regulators (LQR), we develop nonlinear feedback control based on nonlinear model-predictive control and ‘LQR-Trees’. Through simulation using a flat-plate model of the glider, we find that both nonlinear methods are capable of achieving an accurate bird-like perching maneuver from a large range of initial conditions; the ‘LQR-Trees’ algorithm is particularly useful due to its low computational burden at runtime and its inherent performance guarantees. With this in mind, we then implement the ‘LQR-Trees’ algorithm on real hardware and demonstrate a 95 percent perching success rate over 147 flights for a wide range of initial speeds. These results suggest that, at least in the absence of significant disturbances like wind gusts, complex wing morphology and sensing are not strictly required to achieve accurate and robust perching even in the post-stall flow regime. (papers)

Nonlinear Aeroelastic Study of Stall Induced Oscillation in a Symmetric Airfoil

NARCIS (Netherlands)

Sarkar, S.; Bijl, H.

2006-01-01

In this paper the aeroelastic stability of a wind turbine rotor in the dynamic stall regime is investigated. Increased flexibility of modern turbine blades makes them more susceptible to aeroelastic instabilities. Complex oscillation modes like flap/lead-lag are of particular concern, which give way

Pressure-based high-order TVD methodology for dynamic stall control

Science.gov (United States)

Yang, H. Q.; Przekwas, A. J.

1992-01-01

The quantitative prediction of the dynamics of separating unsteady flows, such as dynamic stall, is of crucial importance. This six-month SBIR Phase 1 study has developed several new pressure-based methodologies for solving 3D Navier-Stokes equations in both stationary and moving (body-comforting) coordinates. The present pressure-based algorithm is equally efficient for low speed incompressible flows and high speed compressible flows. The discretization of convective terms by the presently developed high-order TVD schemes requires no artificial dissipation and can properly resolve the concentrated vortices in the wing-body with minimum numerical diffusion. It is demonstrated that the proposed Newton's iteration technique not only increases the convergence rate but also strongly couples the iteration between pressure and velocities. The proposed hyperbolization of the pressure correction equation is shown to increase the solver's efficiency. The above proposed methodologies were implemented in an existing CFD code, REFLEQS. The modified code was used to simulate both static and dynamic stalls on two- and three-dimensional wing-body configurations. Three-dimensional effect and flow physics are discussed.

Ingestive behavior of lambs confined in individual and group stalls.

Science.gov (United States)

Filho, A Eustáquio; Carvalho, G G P; Pires, A J V; Silva, R R; Santos, P E F; Murta, R M; Pereira, F M

2014-02-01

The experiment was conducted to evaluate the ingestive behavior of lambs confined in individual and group stalls. We used thirty-four lambs in their growing phase, aged an average of three months, with mean initial live weight of 17.8±5.2 kg. They were allotted in a completely randomized design with 24 animals kept in individual stalls and 10 animals confined as a group. The experiment lasted for a total of 74 days, and the first 14 days were dedicated to the animals' adaption to the management, facilities and diets. The data collection period lasted 60 days, divided into three 20-d periods for the behavior evaluation. The animals were subjected to five days of visual observation during the experiment period, by the quantification of 24 h a day, with evaluations on the 15th day of each period and an interim evaluation consisting of two consecutive days on the 30th and 31st day of the experiment. The animals confined as a group consumed less (pbehavior.

A Method to Predict Compressor Stall in the TF34-100 Turbofan Engine Utilizing Real-Time Performance Data

Science.gov (United States)

2015-06-01

A METHOD TO PREDICT COMPRESSOR STALL IN THE TF34-100 TURBOFAN ENGINE UTILIZING REAL-TIME PERFORMANCE...THE TF34-100 TURBOFAN ENGINE UTILIZING REAL-TIME PERFORMANCE DATA THESIS Presented to the Faculty Department of Systems Engineering and...036 A METHOD TO PREDICT COMPRESSOR STALL IN THE TF34-100 TURBOFAN ENGINE UTILIZING REAL-TIME PERFORMANCE DATA Shuxiang ‘Albert’ Li, BS

Flow Observations with Tufts and Lampblack of the Stalling of Four Typical Airfoil Sections in the NACA Variable-density Tunnel

Science.gov (United States)

Abbott, Ira H; Sherman, Albert

1938-01-01

A preliminary investigation of the stalling processes of four typical airfoil sections was made over the critical range of the Reynolds Number. Motion pictures were taken of the movements of small silk tufts on the airfoil surface as the angle of attack increased through a range of angles including the stall. The boundary-layer flow also at certain angles of attack was indicated by the patterns formed by a suspension of lampblack in oil brushed onto the airfoil surface. These observations were analyzed together with corresponding force-test measurements to derive a picture of the stalling processes of airfoils.

Indoor and outdoor concentrations of RSP, NO2 and selected volatile organic compounds at 32 shoe stalls located near busy roadways in Seoul, Korea

International Nuclear Information System (INIS)

Bae, Hyunjoo; Chung, Moonho; Yang, Wonho

2004-01-01

It is suspected that persons who work in indoor environments near busy roadways are exposed to elevated levels of air pollutants during working hours. This study evaluated the potential exposure and source contribution associated with traffic-related air pollution for workers (polishers and repairmen) in shoe stalls from each of 32 districts during working hours in Seoul, Korea. The shoe stalls have been located at very close distances to the busy roadways. In this study, shoe stall workers could be exposed to high levels of respirable suspended particulate (RSP), nitrogen dioxide (NO 2 ) and volatile organic compounds (VOCs) from outdoor sources such as traffic exhaust, as well as indoor sources in the shoe stalls such as dust on the shoes, portable gas ranges, organic solvents, adhesives and shoe polish. Compounds of particular note included indoor mean concentrations of benzene, toluene, m/p-xylene and o-xylene were 0.732, 6.777, 4.080 and 1.302 mg/m 3 , respectively, in all shoe stalls. Mean indoor/outdoor ratios for toluene and m/p-xylene concentrations were 54.52 and 20.84, respectively. The contribution of vehicle exhaust emissions to indoor air quality of shoe stalls was identified by means of correlating the relationships between simultaneously measured air pollutant concentrations indoors and outdoors. Unlike RSP and NO 2 , indoor VOCs concentrations of shoe stalls mainly originated from indoor sources vs. outdoor sources

Self-induced vibrations of a DU96-W-180 airfoil in stall

DEFF Research Database (Denmark)

Skrzypinski, Witold Robert; Gaunaa, Mac; Sørensen, Niels N.

2014-01-01

This work presents an analysis of two-dimensional (2D) and three-dimensional (3D) non-moving, prescribed motion and elastically mounted airfoil computational fluid dynamics (CFD) computations. The elastically mounted airfoil computations were performed by means of a 2D structural model with two...... degrees of freedom. The computations aimed at investigating the mechanisms of both vortex-induced and stall-induced vibrations related to a wind turbine blade at standstill conditions. In this work, a DU96-W-180 airfoil was used in the angle-of-attack region potentially corresponding to stallinduced...... vibrations. The analysis showed significant differences between the aerodynamic stability limits predicted by 2D and 3D CFD computations. A general agreement was reached between the prescribed motion and elastically mounted airfoil computations. 3D computations indicated that vortex-induced vibrations...

Short revolving wings enable hovering animals to avoid stall and reduce drag

Science.gov (United States)

Lentink, David; Kruyt, Jan W.; Heijst, Gertjan F.; Altshuler, Douglas L.

2014-11-01

Long and slender wings reduce the drag of airplanes, helicopters, and gliding animals, which operate at low angle of attack (incidence). Remarkably, there is no evidence for such influence of wing aspect ratio on the energetics of hovering animals that operate their wings at much higher incidence. High incidence causes aircraft wings to stall, hovering animals avoid stall by generating an attached vortex along the leading edge of their wings that elevates lift. Hypotheses that explain this capability include the necessity for a short radial distance between the shoulder joint and wing tip, measured in chord lengths, instead of the long tip-to-tip distance that elevates aircraft performance. This stems from how hovering animals revolve their wings around a joint, a condition for which the precise effect of aspect ratio on stall performance is unknown. Here we show that the attachment of the leading edge vortex is determined by wing aspect ratio with respect to the center of rotation-for a suite of aspect ratios that represent both animal and aircraft wings. The vortex remains attached when the local radius is shorter than 4 chord lengths, and separates outboard on more slender wings. Like most other hovering animals, hummingbirds have wing aspect ratios between 3 and 4, much stubbier than helicopters. Our results show this makes their wings robust against flow separation, which reduces drag below values obtained with more slender wings. This revises our understanding of how aspect ratio improves performance at low Reynolds numbers.

Animal hygiene assessment of microclimate in semi open free-stall barns for dairy cows

Directory of Open Access Journals (Sweden)

D. Dimov

2017-03-01

Full Text Available Abstract. The study was conducted in three semi open free-stall barns (B1, B2, and B3 for dairy cows with capacities for 120, 120 and 500 cows, respectively, from three different dairy farms (F-1, F-2 and F-3, situated in Central Southern Bulgaria. The investigated farms had the same production system – loose housing in semi open free-stall dairy barn. For each of the farms the main microclimatic parameters – air temperature, relative humidity and speed of airflow were recorded twice a month at 10.00 h 12.00 h, 14.00 h, 16.00 h and 18.00 h of the day inside the barns in three main technological zones - above the stalls, above manure and feed alleys and outside the buildings. It was found that: a Microclimatic parameters (air temperature, air relative humidity and speed of airflow in technological zones (above the stalls, the manure and feed alleys of three semi open free-stall dairy barns meet the animal hygienic requirements for all seasons according to Regulation No. 44 (2006. Exceptions are some values of relative humidity in B1 and B2 in the spring, and in B1 in winter and summer, which are lower than the minimum humidity (50% according to the standard. b The investigated barns are characterized with poor insulation and do not provide enough isolation from the external ambient temperatures. With the exception of winter, the temperature of the air inside the buildings was lower than that outside, with minor differences for all seasons. The fans in the barns have no effect on the inside air temperature, especially in summer. There was a risk of higher temperatures mainly during the summer period. c There is no significant difference between the average temperatures, air humidity and speed of airflow in all technological zones of the investigated barns. d The largest and statistically significant is the difference between the relative air humidity outside and inside the building in Farm 3, followed by buildings in Farm 1 and 2, where the

Power control of a wind farm with active stall wind turbines and AC grid connection

DEFF Research Database (Denmark)

Hansen, Anca Daniela; Sørensen, Poul; Iov, Florin

both the control on wind turbine level as well as the central control on the wind farm level. The ability of active stall wind farms with AC grid connection to regulate the power production to the reference power ordered by the operators is assessed and discussed by means of simulations.......This paper describes the design of a centralised wind farm controller for a wind farm made-up exclusively of active stall wind turbines with AC grid connection. The overall aim of such controller is to enable the wind farms to provide the best grid support. The designed wind farm control involves...

REVIVAL OF THE STALLED CORE-COLLAPSE SUPERNOVA SHOCK TRIGGERED BY PRECOLLAPSE ASPHERICITY IN THE PROGENITOR STAR

International Nuclear Information System (INIS)

Couch, Sean M.; Ott, Christian D.

2013-01-01

Multi-dimensional simulations of advanced nuclear burning stages of massive stars suggest that the Si/O layers of presupernova stars harbor large deviations from the spherical symmetry typically assumed for presupernova stellar structure. We carry out three-dimensional core-collapse supernova simulations with and without aspherical velocity perturbations to assess their potential impact on the supernova hydrodynamics in the stalled-shock phase. Our results show that realistic perturbations can qualitatively alter the postbounce evolution, triggering an explosion in a model that fails to explode without them. This finding underlines the need for a multi-dimensional treatment of the presupernova stage of stellar evolution

REVIVAL OF THE STALLED CORE-COLLAPSE SUPERNOVA SHOCK TRIGGERED BY PRECOLLAPSE ASPHERICITY IN THE PROGENITOR STAR

Energy Technology Data Exchange (ETDEWEB)

Couch, Sean M. [Flash Center for Computational Science, Department of Astronomy and Astrophysics, University of Chicago, Chicago, IL 60637 (United States); Ott, Christian D., E-mail: smc@flash.uchichago.edu, E-mail: cott@tapir.caltech.edu [TAPIR, Mailcode 350-17, California Institute of Technology, Pasadena, CA 91125 (United States)

2013-11-20

Multi-dimensional simulations of advanced nuclear burning stages of massive stars suggest that the Si/O layers of presupernova stars harbor large deviations from the spherical symmetry typically assumed for presupernova stellar structure. We carry out three-dimensional core-collapse supernova simulations with and without aspherical velocity perturbations to assess their potential impact on the supernova hydrodynamics in the stalled-shock phase. Our results show that realistic perturbations can qualitatively alter the postbounce evolution, triggering an explosion in a model that fails to explode without them. This finding underlines the need for a multi-dimensional treatment of the presupernova stage of stellar evolution.

Low-Order Modeling of Dynamic Stall on Airfoils in Incompressible Flow

Science.gov (United States)

Narsipur, Shreyas

Unsteady aerodynamics has been a topic of research since the late 1930's and has increased in popularity among researchers studying dynamic stall in helicopters, insect/bird flight, micro air vehicles, wind-turbine aerodynamics, and ow-energy harvesting devices. Several experimental and computational studies have helped researchers gain a good understanding of the unsteady ow phenomena, but have proved to be expensive and time-intensive for rapid design and analysis purposes. Since the early 1970's, the push to develop low-order models to solve unsteady ow problems has resulted in several semi-empirical models capable of effectively analyzing unsteady aerodynamics in a fraction of the time required by high-order methods. However, due to the various complexities associated with time-dependent flows, several empirical constants and curve fits derived from existing experimental and computational results are required by the semi-empirical models to be an effective analysis tool. The aim of the current work is to develop a low-order model capable of simulating incompressible dynamic-stall type ow problems with a focus on accurately modeling the unsteady ow physics with the aim of reducing empirical dependencies. The lumped-vortex-element (LVE) algorithm is used as the baseline unsteady inviscid model to which augmentations are applied to model unsteady viscous effects. The current research is divided into two phases. The first phase focused on augmentations aimed at modeling pure unsteady trailing-edge boundary-layer separation and stall without leading-edge vortex (LEV) formation. The second phase is targeted at including LEV shedding capabilities to the LVE algorithm and combining with the trailing-edge separation model from phase one to realize a holistic, optimized, and robust low-order dynamic stall model. In phase one, initial augmentations to theory were focused on modeling the effects of steady trailing-edge separation by implementing a non-linear decambering

Dairy cows welfare quality in tie-stall housing system with or without access to exercise

Science.gov (United States)

2013-01-01

Background Tie-stall housing of dairy cows is used extensively worldwide, despite of the welfare concerns regarding the restriction of voluntary movement and limitation of expression of the cows’ natural behaviour. The aim of this study was to compare the welfare quality of dairy cows kept in two types of tie-stall housing systems: with regular outdoor exercise and without access to exercise. In addition, the study investigated the relationship between different welfare measures of dairy cows kept in tie-stalls. Methods 3,192 lactating cows were assessed using the Welfare Quality® assessment protocol for cattle in 80 commercial dairy farms, half of the farms providing outdoor access for the animals to exercise. The descriptive statistical indicators were determined for the assessed measures and for the welfare criteria and principle scores. The data obtained in the two housing types were compared and the correlation coefficients were calculated between the different welfare measures. Results The significant differences found between the two housing systems for the majority of the animal based measures indicate the positive effect of exercise on the welfare of tethered cows. Many of the animal welfare parameters correlated with each other. For the farms allowing the cows’ turnout in a paddock, pasture or both, the mean scores for the welfare criteria and principles were higher than for the farms with permanent tethering of the cows, except the criteria absence of prolonged hunger and expression of social behaviours. The lowest scores were obtained for the criterion positive emotional state, in both housing systems. With regard to the overall classification, none of the farms were considered excellent. In the not classified category were only farms with all-year-round tethering of the animals and in the enhanced category only farms where the cows had outdoor access. Conclusions The welfare quality of the investigated dairy cows was significantly better in the

Lift hysteresis at stall as an unsteady boundary-layer phenomenon

Science.gov (United States)

Moore, Franklin K

1956-01-01

Analysis of rotating stall of compressor blade rows requires specification of a dynamic lift curve for the airfoil section at or near stall, presumably including the effect of lift hysteresis. Consideration of the magnus lift of a rotating cylinder suggests performing an unsteady boundary-layer calculation to find the movement of the separation points of an airfoil fixed in a stream of variable incidence. The consideration of the shedding of vorticity into the wake should yield an estimate of lift increment proportional to time rate of change of angle of attack. This increment is the amplitude of the hysteresis loop. An approximate analysis is carried out according to the foregoing ideas for a 6:1 elliptic airfoil at the angle of attack for maximum lift. The assumptions of small perturbations from maximum lift are made, permitting neglect of distributed vorticity in the wake. The calculated hysteresis loop is counterclockwise. Finally, a discussion of the forms of hysteresis loops is presented; and, for small reduced frequency of oscillation, it is concluded that the concept of a viscous "time lag" is appropriate only for harmonic variations of angle of attack with time at mean conditions other than maximum lift.

MICROBIOLOGICAL STUDY ON ICE FROM A FISH STALL

Directory of Open Access Journals (Sweden)

E. Tirloni

2012-08-01

Full Text Available The ice used for exposure of fish products could be a source of secondary contamination due to ice machine, due to not respected good manufacturing practices, particularly when ice is left on the fish stall and the next day the new layer is deposited over the old one. Aim of this study was the verification of the hygienic risk of this procedure through analyses of the liquid produced by the zones “thawed cephalopods” and “fresh whole fish”. Almost the microorganisms found were Gram negative (in particular Pseudomonadaceae.

An automatic system for the detection of dairy cows lying behaviour in free-stall barns

Directory of Open Access Journals (Sweden)

Simona M.C. Porto

2013-09-01

Full Text Available In this paper, a method for the automatic detection of dairy cow lying behaviour in free-stall barns is proposed. A computer visionbased system (CVBS composed of a video-recording system and a cow lying behaviour detector based on the Viola Jones algorithm was developed. The CVBS performance was tested in a head-to-head free stall barn. Two classifiers were implemented in the software component of the CVBS to obtain the cow lying behaviour detector. The CVBS was validated by comparing its detection results with those generated from visual recognition. This comparison allowed the following accuracy indices to be calculated: the branching factor (BF, the miss factor (MF, the sensitivity, and the quality percentage (QP. The MF value of approximately 0.09 showed that the CVBS missed one cow every 11 well detected cows. Conversely, the BF value of approximately 0.08 indicated that one false positive was detected every 13 well detected cows. The high value of approximately 0.92 obtained for the sensitivity index and that obtained for QP of about 0.85 revealed the ability of the proposed system to detect cows lying in the stalls.

Inviscid double wake model for stalled airfoils

International Nuclear Information System (INIS)

Marion, L; Ramos-García, N; Sørensen, J N

2014-01-01

An inviscid double wake model based on a steady two-dimensional panel method has been developed to predict aerodynamic loads of wind turbine airfoils in the deep stall region. The separated flow is modelled using two constant vorticity sheets which are released at the trailing edge and at the separation point. A calibration of the code through comparison with experiments has been performed using one set of airfoils. A second set of airfoils has been used for the validation of the calibrated model. Predicted aerodynamic forces for a wide range of angles of attack (0 to 90 deg) are in overall good agreement with wind tunnel measurements

Zonal RANS/LES coupling simulation of a transitional and separated flow around an airfoil near stall

Energy Technology Data Exchange (ETDEWEB)

Richez, F.; Mary, I.; Gleize, V. [ONERA, Department of Computational Fluid Dynamics and Aeroacoustics, 29 Avenue de la Division Leclerc, BP 72, Chatillon (France); Basdevant, C. [Universite Paris-Nord, Laboratoire d' Analyse, Geometrie et Applications, CNRS, Villetaneuse (France)

2008-05-15

The objective of the current study is to examine the course of events leading to stall just before its occurrence. The stall mechanisms are very sensitive to the transition that the boundary layer undergoes near the leading edge of the profile by a so-called laminar separation bubble (LSB). In order to provide helpful insights into this complex flow, a zonal Reynolds-averaged Navier-Stokes (RANS)/large-eddy simulation (LES) simulation of the flow around an airfoil near stall has been achieved and its results are presented and analyzed in this paper. LSB has already been numerically studied by direct numerical simulation (DNS) or LES, but for a flat plate with an adverse pressure gradient only. We intend, in this paper, to achieve a detailed analysis of the transition process by a LSB in more realistic conditions. The comparison with a linear instability analysis has shown that the numerical instability mechanism in the LSB provides the expected frequency of the perturbations. Furthermore, the right order of magnitude for the turbulence intensities at the reattachment point is found. (orig.)

Solution structures of the linear leaderless bacteriocins enterocin 7A and 7B resemble carnocyclin A, a circular antimicrobial peptide.

Science.gov (United States)

Lohans, Christopher T; Towle, Kaitlyn M; Miskolzie, Mark; McKay, Ryan T; van Belkum, Marco J; McMullen, Lynn M; Vederas, John C

2013-06-11

Leaderless bacteriocins are a class of ribosomally synthesized antimicrobial peptides that are produced by certain Gram-positive bacteria without an N-terminal leader section. These bacteriocins are of great interest due to their potent inhibition of many Gram-positive organisms, including food-borne pathogens such as Listeria and Clostridium spp. We now report the NMR solution structures of enterocins 7A and 7B, leaderless bacteriocins recently isolated from Enterococcus faecalis 710C. These are the first three-dimensional structures to be reported for bacteriocins of this class. Unlike most other linear Gram-positive bacteriocins, enterocins 7A and 7B are highly structured in aqueous conditions. Both peptides are primarily α-helical, adopting a similar overall fold. The structures can be divided into three separate α-helical regions: the N- and C-termini are both α-helical, separated by a central kinked α-helix. The overall structures bear an unexpected resemblance to carnocyclin A, a 60-residue peptide that is cyclized via an amide bond between the C- and N-termini and has a saposin fold. Because of synergism observed for other two-peptide leaderless bacteriocins, it was of interest to probe possible binding interactions between enterocins 7A and 7B. However, despite synergistic activity observed between these peptides, no significant binding interaction was observed based on NMR and isothermal calorimetry.

Suppression of inducer stall based on inlet recirculation in a centrifugal impeller. 1st Report. Improvement in stall limit by ring groove arrangement; Enshin haneguruma iriguchi junkanryu ni yoru inducer shissoku no yokusei. 1. kanjoko ni yoru shissoku genkai no kaizen

Energy Technology Data Exchange (ETDEWEB)

Ueki, H.; Ishida, M.; Sakaguchi, D.; Sun, Z. [Nagasaki University, Nagasaki (Japan). Faculty of Engineering

2000-07-25

A ring groove arrangement is proposed to suppress unstable flow or surge in a centrifugal blower. The ring groove arrangement connects the upstream position of impeller inlet and the inducer throat tip through a bypass. The recirculation flow 'vas formed by the pressure difference between the two positions, and the recirculation flow rate was changed by increasing the ring groove widths. The inlet recirculation results in a decrease in the flow rate of unstable flow inception, and an up to 800 improvement in stall limit was obtained by the ring groove arrangement at a small expense of the delivery pressure drop. The improvement of stall limit in the present experiment seems to be mainly due to decrease in flow incidence based on the inlet recirculation flow. Tre flow incidence decreases more as the recirculation flow rate increases, thus resulting in a larger improvement in stall limit. (author)

Stalled RNAP-II molecules bound to non-coding rDNA spacers are required for normal nucleolus architecture.

Science.gov (United States)

Freire-Picos, M A; Landeira-Ameijeiras, V; Mayán, María D

2013-07-01

The correct distribution of nuclear domains is critical for the maintenance of normal cellular processes such as transcription and replication, which are regulated depending on their location and surroundings. The most well-characterized nuclear domain, the nucleolus, is essential for cell survival and metabolism. Alterations in nucleolar structure affect nuclear dynamics; however, how the nucleolus and the rest of the nuclear domains are interconnected is largely unknown. In this report, we demonstrate that RNAP-II is vital for the maintenance of the typical crescent-shaped structure of the nucleolar rDNA repeats and rRNA transcription. When stalled RNAP-II molecules are not bound to the chromatin, the nucleolus loses its typical crescent-shaped structure. However, the RNAP-II interaction with Seh1p, or cryptic transcription by RNAP-II, is not critical for morphological changes. Copyright © 2013 John Wiley & Sons, Ltd.

A Beddoes-Leishman type dynamic stall model in state-space and indicial formulations

DEFF Research Database (Denmark)

Hansen, M.H.; Gaunaa, Mac; Aagaard Madsen, Helge

2004-01-01

This report contains a description of a Beddoes-Leishman type dynamic stall model in both a state-space and an indicial function formulation. The model predicts the unsteady aerodynamic forces and moment on an airfoil section undergoing arbitrary motionin heave, lead-lag, and pitch. The model...... features, such as overshoot of the lift, in the stall region. The linearized model is shown to give identicalresults to the full model for small amplitude oscillations. Furthermore, it is shown that the response of finite thichkness airfoils can be reproduced to a high accuracy by the use of specific...... is carried out by comparing the response of the model with inviscid solutions and observing the general behavior of the model using known airfoil data as input. Theproposed dynamic model gives results identical to inviscid solutions within the attached-flow region; and it exhibits the expected dynamic...

Prediction of RNA Polymerase II recruitment, elongation and stalling from histone modification data

DEFF Research Database (Denmark)

Chen, Yun; Jørgensen, Mette; Kolde, Raivo

2011-01-01

of RNAPII stalling. CONCLUSIONS: In this study we introduce a general framework to accurately predict the level of RNAPII recruitment, elongation, stalling and mRNA expression from chromatin signals. The versatility of the method also makes it ideally suited to investigate other genomic data....... strategies are needed to progress from descriptive annotation of data to quantitative, predictive models. RESULTS: Here, we describe a computational framework which with high accuracy can predict the locations of core promoters, the amount of recruited RNAPII at the promoter, the amount of elongating RNAPII...... of these four marks are found to be necessary for recruitment of RNAPII but not sufficient for the elongation. We also show that the spatial distributions of histone marks are almost as predictive as the signal strength and that a set of histone marks immediately downstream of the TSS is highly predictive...

Detecting analogical resemblance without retrieving the source analogy.

Science.gov (United States)

Kostic, Bogdan; Cleary, Anne M; Severin, Kaye; Miller, Samuel W

2010-06-01

We examined whether people can detect analogical resemblance to an earlier experimental episode without being able to recall the experimental source of the analogical resemblance. We used four-word analogies (e.g., robin-nest/beaver-dam), in a variation of the recognition-without-cued-recall method (Cleary, 2004). Participants studied word pairs (e.g., robin-nest) and were shown new word pairs at test, half of which analogically related to studied word pairs (e.g., beaver-dam) and half of which did not. For each test pair, participants first attempted to recall an analogically similar pair from the study list. Then, regardless of whether successful recall occurred, participants were prompted to rate the familiarity of the test pair, which was said to indicate the likelihood that a pair that was analogically similar to the test pair had been studied. Across three experiments, participants demonstrated an ability to detect analogical resemblance without recalling the source analogy. Findings are discussed in terms of their potential relevance to the study of analogical reasoning and insight, as well as to the study of familiarity and recognition memory.

Numerical simulation of the RISOe1-airfoil dynamic stall

Energy Technology Data Exchange (ETDEWEB)

Bertagnolio, F.; Soerensen, N. [Risoe National Lab., Wind Energy and Atmospheric Physics Dept., Roskilde (Denmark)

1997-12-31

In this paper we are concerned with the numerical computation of the dynamic stall that occur in the viscous flowfield over an airfoil. These results are compared to experimental data that were obtained with the new designed RISOe1-airfoil, both for a motionless airfoil and for a pitching motion. Moreover, we present some numerical computations of the plunging and lead-lag motions. We also investigate the possibility of using the pitching motion to simulate the plunging and lead-lag situations. (au)

Preliminary Results of the Determination of Inlet-Pressure Distortion Effects on Compressor Stall and Altitude Operating Limits of the J57-P-1 Turbojet Engine

Science.gov (United States)

Wallner, L. E.; Lubick, R. J.; Chelko, L. J.

1955-01-01

During an investigation of the J57-P-1 turbojet engine in the Lewis altitude wind tunnel, effects of inlet-flow distortion on engine stall characteristics and operating limits were determined. In addition to a uniform inlet-flow profile, the inlet-pressure distortions imposed included two radial, two circumferential, and one combined radial-circumferential profile. Data were obtained over a range of compressor speeds at an altitude of 50,000 and a flight Mach number of 0.8; in addition, the high- and low-speed engine operating limits were investigated up to the maximum operable altitude. The effect of changing the compressor bleed position on the stall and operating limits was determined for one of the inlet distortions. The circumferential distortions lowered the compressor stall pressure ratios; this resulted in less fuel-flow margin between steady-state operation and compressor stall. Consequently, the altitude operating Limits with circumferential distortions were reduced compared with the uniform inlet profile. Radial inlet-pressure distortions increased the pressure ratio required for compressor stall over that obtained with uniform inlet flow; this resulted in higher altitude operating limits. Likewise, the stall-limit fuel flows required with the radial inlet-pressure distortions were considerably higher than those obtained with the uniform inlet-pressure profile. A combined radial-circumferential inlet distortion had effects on the engine similar to the circumferential distortion. Bleeding air between the two compressors eliminated the low-speed stall limit and thus permitted higher altitude operation than was possible without compressor bleed.

Replisome stall events have shaped the distribution of replication origins in the genomes of yeasts

Science.gov (United States)

Newman, Timothy J.; Mamun, Mohammed A.; Nieduszynski, Conrad A.; Blow, J. Julian

2013-01-01

During S phase, the entire genome must be precisely duplicated, with no sections of DNA left unreplicated. Here, we develop a simple mathematical model to describe the probability of replication failing due to the irreversible stalling of replication forks. We show that the probability of complete genome replication is maximized if replication origins are evenly spaced, the largest inter-origin distances are minimized, and the end-most origins are positioned close to chromosome ends. We show that origin positions in the yeast Saccharomyces cerevisiae genome conform to all three predictions thereby maximizing the probability of complete replication if replication forks stall. Origin positions in four other yeasts—Kluyveromyces lactis, Lachancea kluyveri, Lachancea waltii and Schizosaccharomyces pombe—also conform to these predictions. Equating failure rates at chromosome ends with those in chromosome interiors gives a mean per nucleotide fork stall rate of ∼5 × 10−8, which is consistent with experimental estimates. Using this value in our theoretical predictions gives replication failure rates that are consistent with data from replication origin knockout experiments. Our theory also predicts that significantly larger genomes, such as those of mammals, will experience a much greater probability of replication failure genome-wide, and therefore will likely require additional compensatory mechanisms. PMID:23963700

Disruption of PCNA-lamins A/C interactions by prelamin A induces DNA replication fork stalling.

Science.gov (United States)

Cobb, Andrew M; Murray, Thomas V; Warren, Derek T; Liu, Yiwen; Shanahan, Catherine M

2016-09-02

The accumulation of prelamin A is linked to disruption of cellular homeostasis, tissue degeneration and aging. Its expression is implicated in compromised genome stability and increased levels of DNA damage, but to date there is no complete explanation for how prelamin A exerts its toxic effects. As the nuclear lamina is important for DNA replication we wanted to investigate the relationship between prelamin A expression and DNA replication fork stability. In this study we report that the expression of prelamin A in U2OS cells induced both mono-ubiquitination of proliferating cell nuclear antigen (PCNA) and subsequent induction of Pol η, two hallmarks of DNA replication fork stalling. Immunofluorescence microscopy revealed that cells expressing prelamin A presented with high levels of colocalisation between PCNA and γH2AX, indicating collapse of stalled DNA replication forks into DNA double-strand breaks. Subsequent protein-protein interaction assays showed prelamin A interacted with PCNA and that its presence mitigated interactions between PCNA and the mature nuclear lamina. Thus, we propose that the cytotoxicity of prelamin A arises in part, from it actively competing against mature lamin A to bind PCNA and that this destabilises DNA replication to induce fork stalling which in turn contributes to genomic instability.

Visualization by PIV of dynamic stall on a vertical axis wind turbine

NARCIS (Netherlands)

Ferreira, C.J.S.; Kuik, van G.A.M.; Bussel, van G.J.W.; Scarano, F.

2009-01-01

The aerodynamic behavior of a vertical axis wind turbine (VAWT) is analyzed by means of 2D particle image velocimetry (PIV), focusing on the development of dynamic stall at different tip speed ratios. The VAWT has an unsteady aerodynamic behavior due to the variation with the azimuth angle ¿ of the

Ethnic Dimensions of Guatemala's Stalled Transition: A Parity-Specific Analysis of Ladino and Indigenous Fertility Regimes.

Science.gov (United States)

Grace, Kathryn; Sweeney, Stuart

2016-02-01

In some contemporary populations, fertility levels appear to plateau, with women maintaining a consistently high level of fertility for a relatively extended period. Because this plateau does not reflect the historical patterns observed in Europe, the focus of most studies on fertility patterns, mechanisms underlying the plateau and the reinstatement of a decline have not been fully explored and are not fully understood. Through the construction of fertility histories of 25,000 women using multiple years of health survey data, we analyze some of the components of stalled fertility as they pertain to Guatemala, the only Central American country to have experienced a stalled fertility decline.

Associations of soft flooring materials in free stalls with milk yield, clinical mastitis, teat lesions, and removal of dairy cows.

Science.gov (United States)

Ruud, L E; Bøe, K E; Osterås, O

2010-04-01

The objective was to test if there was an association between free-stall base softness and milk yield, incidence of clinical mastitis (CM), teat lesions, and removal of cows. In a questionnaire sent to 1,923 dairy farms presumed to be using free-stall housing, farmers were asked for information regarding housing and stall base; for example, the year of installation and the product name or brand of their mats or mattresses. This information was merged with data for milk yield, CM, teat lesions, and removal of cows extracted from the Norwegian Dairy Herd Recording System for the years after installation of mats or mattresses. After exclusion of invalid contributions, the data set consisted of 29,326 lactations for milk yield distributed over 363 free-stalled herds in Norway. The farms were stratified into 5 categories according to the softness of the stall surface measured as millimeter impact of a sphere with a diameter of 120 mm at 2-kN load: 1=concrete, softness of 0mm; 2=rubber, softness of 1 to 8mm; 3=soft mats, softness of 9 to 16 mm; 4=multilayer mats, softness of 17 to 24 mm; and 5=mattresses, softness over 24 mm. Lactation curves were estimated as modified Wood's lactation curves using test-day data and mixed models with repeated measurements, adjusting for days in milk, parity, and softness of free-stall flooring. Herds on concrete free-stall bases yielded 6,727+/-146 kg of milk from 5 to 305 days in milk. In comparison, herds showed a decrease of 0.3% on rubber, an increase of 2.4% on soft mats, an increase of 4.5% on multilayer mats, and an increase of 3.9% on mattresses. Compared with concrete, the hazard ratio (HR) of CM was less on rubber, multilayer mats, and mattresses [HR=0.89 (0.79-0.99), 0.85 (0.73-0.996), and 0.80 (0.73-0.88), respectively]. Compared with concrete, the HR of teat lesions was less on rubber, soft mats, multilayer mats, and mattresses [HR=0.41 (0.26-0.65), 0.33 (0.24-0.44), 0.12 (0.04-0.38), and 0.47 (0.33-0.67), respectively]. The

Stall Recovery in a Centrifuge-Based Flight Simulator With an Extended Aerodynamic Model

NARCIS (Netherlands)

Ledegang, W.D.; Groen, E.L.

2015-01-01

We investigated the performance of 12 airline pilots in recovering from an asymmetrical stall in a flight simulator featuring an extended aerodynamic model of a transport-category aircraft, and a centrifuge-based motion platform capable of generating enhanced buffet motion and g-cueing. All pilots

Critical 23S rRNA interactions for macrolide-dependent ribosome stalling on the ErmCL nascent peptide chain.

Science.gov (United States)

Koch, Miriam; Willi, Jessica; Pradère, Ugo; Hall, Jonathan; Polacek, Norbert

2017-06-20

The nascent peptide exit tunnel has recently been identified as a functional region of ribosomes contributing to translation regulation and co-translational protein folding. Inducible expression of the erm resistance genes depends on ribosome stalling at specific codons of an upstream open reading frame in the presence of an exit tunnel-bound macrolide antibiotic. The molecular basis for this translation arrest is still not fully understood. Here, we used a nucleotide analog interference approach to unravel important functional groups on 23S rRNA residues in the ribosomal exit tunnel for ribosome stalling on the ErmC leader peptide. By replacing single nucleobase functional groups or even single atoms we were able to demonstrate the importance of A2062, A2503 and U2586 for drug-dependent ribosome stalling. Our data show that the universally conserved A2062 and A2503 are capable of forming a non-Watson-Crick base pair that is critical for sensing and transmitting the stalling signal from the exit tunnel back to the peptidyl transferase center of the ribosome. The nucleobases of A2062, A2503 as well as U2586 do not contribute significantly to the overall mechanism of protein biosynthesis, yet their elaborate role for co-translational monitoring of nascent peptide chains inside the exit tunnel can explain their evolutionary conservation. © The Author(s) 2017. Published by Oxford University Press on behalf of Nucleic Acids Research.

Microbiological quality of air in free-range and box-stall stable horse keeping systems.

Science.gov (United States)

Wolny-Koładka, Katarzyna

2018-04-07

The aim of this study was to assess the microbiological quality of air in three horse riding centers differing in the horse keeping systems. The air samples were collected in one facility with free-range horse keeping system and two with box stalls of different sizes. The samples were collected over a period of 3 years (2015-2017), four times per year (spring, summer, autumn, winter) to assess the effect of seasonal changes. The prevalence of aerobic mesophilic bacteria, mold fungi, actinomycetes, Staphylococcus spp., and Escherichia coli was determined by the air collision method on Petri dishes with appropriate microbiological media. At the same time, air temperature, relative humidity, and particulate matter concentration (PM 10 , PM 2.5 ) were measured. It was found that the horse keeping system affects the occurrence of the examined airborne microorganisms. Over the 3-year period of study, higher temperature and humidity, as well as particulate matter concentration-which notoriously exceeded limit values-were observed in the facilities with the box-stall system. The air sampled from the largest horse riding center, with the largest number of horses and the box-stall system of horse keeping, was also characterized by the heaviest microbiological contamination. Among others, bacteria from the following genera: Staphylococcus spp., Streptococcus spp., Bacillus spp., and E. coli and fungi from the genera Aspergillus, Fusarium, Mucor, Rhizopus, Penicillium, Trichothecium, Cladosporium, and Alternaria were identified in the analyzed samples.

Why Do Promising Therapies Stall in Development and How Can We Move Them Forward?

Science.gov (United States)

Wegner, Craig D; Goodwin, Andrew; Cook, Jon C; Allamneni, Krishna; Sohn, Jane; McVean, Maralee

There are many reasons that molecules fail to progress to market and various principles of risk-benefit decisions that can help drive the molecule through development. This symposium included discussions on global strategies involved in pushing promising molecules to market, what to do when a molecule stalls in its progress to market, and options for rescuing the molecule and pushing it forward again. Innovative partnerships that bring stalled drugs back into clinical development were also addressed. A regulatory perspective on common reasons for a molecule to fail in its forward progress was presented. In addition, situations arise when a third-party advisory committee can provide input to help overcome issues identified by a regulatory agency. Using examples from the private and public domain, presentations centered on how to repurpose a molecule and when more science is needed.

Cooling systems of the resting area in free stall dairy barn

Science.gov (United States)

Calegari, F.; Calamari, L.; Frazzi, E.

2016-04-01

A study during the summer season evaluated the effect of different cooling systems on behavioral and productive responses of Italian Friesian dairy cows kept in an experimental-free stall barn located in the Po Valley in Italy. The study involved 30 lactating dairy cows subdivided into two groups kept in two pens with external hard court paddock in each free stall. The same cooling system was applied in the feeding area in both pens. A different cooling system in the resting area was applied to the two pens: in the pen SW, the resting area was equipped with fans and misters; in the other, there was simple ventilation (SV). Breathing rate, rectal temperature, milk yield, and milk characteristics (fat, protein, and somatic cell count) were measured. Behavioral activities (standing and lying cows in the different areas, as well as the animals in the feed bunk) were recorded. Mild to moderate heat waves during the trial were observed. On average, the breathing rate was numerically greater in SV compared with SW cows (60.2 and 55.8 breath/min, respectively), and mean rectal temperature remained below 39 °C in both groups during the trial (on average 38.7 and 38.8 °C in SV and SW, respectively. During the hotter periods of the trial, the time spent lying indoor in the free stall was greater in SW (11.8 h/day) than SV (10.7 h/day). Conversely, the time spent standing indoor without feeding was greater in SV (4.3 h/day) than SW (3.8 h/day). Milk yield was slightly better maintained during hotter period in SW compared with SV and somatic cell count was also slightly greater in the former. In conclusion, the adoption of the cooling system by means of evaporative cooling also in the resting area reduces the alteration of time budget caused by heat stress.

Miscoding-induced stalling of substrate translocation on the bacterial ribosome.

Science.gov (United States)

Alejo, Jose L; Blanchard, Scott C

2017-10-10

Directional transit of the ribosome along the messenger RNA (mRNA) template is a key determinant of the rate and processivity of protein synthesis. Imaging of the multistep translocation mechanism using single-molecule FRET has led to the hypothesis that substrate movements relative to the ribosome resolve through relatively long-lived late intermediates wherein peptidyl-tRNA enters the P site of the small ribosomal subunit via reversible, swivel-like motions of the small subunit head domain within the elongation factor G (GDP)-bound ribosome complex. Consistent with translocation being rate-limited by recognition and productive engagement of peptidyl-tRNA within the P site, we now show that base-pairing mismatches between the peptidyl-tRNA anticodon and the mRNA codon dramatically delay this rate-limiting, intramolecular process. This unexpected relationship between aminoacyl-tRNA decoding and translocation suggests that miscoding antibiotics may impact protein synthesis by impairing the recognition of peptidyl-tRNA in the small subunit P site during EF-G-catalyzed translocation. Strikingly, we show that elongation factor P (EF-P), traditionally known to alleviate ribosome stalling at polyproline motifs, can efficiently rescue translocation defects arising from miscoding. These findings help reveal the nature and origin of the rate-limiting steps in substrate translocation on the bacterial ribosome and indicate that EF-P can aid in resuming translation elongation stalled by miscoding errors.

Unsteady performance of a cavitating hydrofoil in stall conditions. Shissoku jotai ni okeru yokukei no hiteijo tokusei

Energy Technology Data Exchange (ETDEWEB)

Ogata, H. (Tohoku University, Sendai (Japan)); Ito, Y. (Hachinoe Institutea of Technology, Aomori (Japan)); Oba, R. (Tohoku University, Sendai (Japan). Institute of Fluid Science); Sunayama, Y.; Abe, J. (Suzuki Co. Ltd., Shizuoka (Japan))

1991-11-25

To elucidate the unsteady performance of cavitating hydrofoils in a stall condition, this paper describes a survey on unsteady conditions without cavitations and stall conditions as to their characteristics from a cavitation to a supercavitation, lift and drag. Flows with cavitations were also analyzed. As a result of comparing also data for the subcavitation regions, it was found that a large-scale vortex generation on the hydrofoil back-pressure plane in near stall condition has a close relation with the changes in lifts and drags or the cavitation breakdown. The experiment used a testing water tank of circulation flow type having a rectangular measuring cross section (70 mm in width and 190 mm in height), and the hydrofoil specimens of two-dimensional symmetric type with a chord length of 70 mm and an aspect ratio of 1.0. The test condition used a cavitation coefficient of 0.18-6.33 (from a supercavitation to non-cavitation). A numerical analysis proved that the power spectra around the hydrofoils having no cavitations agreed with the experimental results, and verified the reasonability of the application. 18 refs., 8 figs., 2 tabs.

Wave energy plants: Control strategies for avoiding the stalling behaviour in the Wells turbine

Energy Technology Data Exchange (ETDEWEB)

Amundarain, Modesto; Alberdi, Mikel; Garrido, Aitor J.; Garrido, Izaskun; Maseda, Javier [Dept. of Automatic Control and Systems Engineering, EUITI Bilbao, University of the Basque Country, Plaza de la Casilla 3, 48012 Bilbao (Spain)

2010-12-15

This study analyzes the problem of the stalling behaviour in Wells turbines, one of the most widely used turbines in wave energy plants. For this purpose two different control strategies are presented and compared. In the first one, a rotational speed control system is employed to appropriately adapt the speed of the double-fed induction generator coupling to the turbine, according to the pressure drop entry. In the second control strategy, an airflow control regulates the power generated by the turbine generator module by means of the modulation valve avoiding the stalling behaviour. It is demonstrated that the proposed rotational speed control design adequately matches the desired relationship between the slip of the double-fed induction generator and the pressure drop input, whilst the valve control using a traditional PID controller successfully governs the flow that modulates the pressure drop across the turbine. (author)

A Detailed Study of the Rotational Augmentation and Dynamic Stall Phenomena for Wind Turbines

DEFF Research Database (Denmark)

Guntur, Srinivas

This thesis presents investigations into the aerodynamics of wind turbine rotors, with a focus on the in-board sections of the rotor. Two important aerodynamic phenomena that have challenged scientists over nearly the last half a century are the so-called rotational augmentation and dynamic stall....... This thesis presents an investigation into these two phenomena, using data from the MEXICO and the NREL UAE Phase VI experiments, as well as data obtained from full rotor CFD computations carried out using the in-house flow solver Ellipsys3D. The experimental data, CFD data and that from some of the existing...... on wind turbine blades using the N-sequence data of the NREL UAE Phase VI experiment. The experimental data is compared with the results from unsteady Delayed Detached Eddy Simulations (DDES). The same conditions are also modelled using a Beddoes-Leishman type dynamic stall model by Hansen et al. (2004...

Computer modeling of the stalled flow of a rotating cylinder and the reverse magnus effect

Science.gov (United States)

Belotserkovskii, S. M.; Kotovskii, V. N.; Nisht, M. I.; Fedorov, R. M.

1985-02-01

Unsteady stalled flow around a rotating cylinder is investigated in a numerical experiment. Attention is mostly given to the reverse Magnus effect which was discovered in tube experiments at some critical rotational speed of the cylinder.

Association between stall surface and some animal welfare measurements in freestall dairy herds using recycled manure solids for bedding.

Science.gov (United States)

Husfeldt, A W; Endres, M I

2012-10-01

The objective of this cross-sectional study was to investigate the association between stall surface and some animal welfare measurements in upper Midwest US dairy operations using recycled manure solids as bedding material. The study included 34 dairy operations with herd sizes ranging from 130 to 3,700 lactating cows. Forty-five percent of the herds had mattresses and 55% had deep-bedded stalls. Farms were visited once between July and October 2009. At the time of visit, at least 50% of the cows in each lactating pen were scored for locomotion, hygiene, and hock lesions. On-farm herd records were collected for the entire year and used to investigate mortality, culling, milk production, and mastitis incidence. Stall surface was associated with lameness and hock lesion prevalence. Lameness prevalence (locomotion score ≥ 3 on a 1 to 5 scale) was lower in deep-bedded freestalls (14.4%) than freestalls with mattresses (19.8%). Severe lameness prevalence (locomotion score ≥ 4) was also lower for cows housed in deep-bedded freestalls (3.6%) than for cows housed in freestalls with mattresses (5.9%). In addition, the prevalence of hock lesions (hock lesion scores ≥ 2 on a 1 to 3 scale, with 1=no lesion, 2=hair loss or mild lesion, and 3=swelling or severe lesion) and severe hock lesions (hock lesion score=3) was lower in herds with deep-bedded freestalls (49.4%; 6.4%) than in herds with mattresses (67.3%; 13.2%). Herd turnover rates were not associated with stall surface; however, the percentage of removals due to voluntary (low milk production, disposition, and dairy) and involuntary (death, illness, injury, and reproductive) reasons was different between deep-bedded and mattress-based freestalls. Voluntary removals averaged 16% of all herd removals in deep-bedded herds, whereas in mattress herds, these removals were 8%. Other welfare measurements such as cow hygiene, mortality rate, mastitis incidence, and milk production were not associated with stall surface

Experimental study of dynamic stall on Darrieus wind turbine blades

Science.gov (United States)

Brochier, G.; Fraunie, P.; Beguier, C.; Paraschivoiu, I.

1985-12-01

An experimental study of periodic vortex phenomena was performed on a model of a two straight-bladed Darrieus wind turbine under controlled-rotation conditions in the IMST water tunnel. The main focus of interest was the tip-speed ratios at which dynamic stall appears. Observations of this phenomenon from dye emission and the formation of hydrogen bubbles were made in the form of photographs, film and video recordings. Velocity measurements were obtained using the Laser-Doppler Velocimeter and components of velocity fluctuations could be determined quantitatively.

The Relationships between Selection and Processing Food with Escherichia coli Contaminant on Food Stall Serving

Directory of Open Access Journals (Sweden)

Tris Eryando

2014-04-01

Full Text Available Escherichia coli in food stalls surrounding the X Campuss in Depok, year 2012. The research conducted to examine food safety, which were served in surrounding the campus X in Depok. Escherichia coli (E. coli existence was used to indicate the quality of hygiene and sanitation of the food that was served. Using the cross sectional method, the research examined the persons who served the food to be sold in the food stalls in the campus. There were 173 food servers chosen as the respondents from 10 different food stalls around the university. The existence of E. coli examined in the microbiology laboratory in the Faculty of Public Health. Using the most probable number (MPN method found that 59.54% of the food served in the campus were contaminated E. coli. Factors affecting the existence of E. coli were the raw materials (vegetables treated and the length of cooking of the materials (rice/beens. The improper treatment such as washing with no running water or even unwashed vegetables had 5 times risk of the E. coli contamination. Cooking less than 15 minutes was also more risky than cooking more than 15 minutes. As a result, this is very important to find a method to improve knowledge and to increase practical skills in food safety. Furthermore, in this research area may give contribution to avoid E. coli contamination which will prevent unnecessary illness among students in the campus.

Facial Resemblance Exaggerates Sex-Specific Jealousy-Based Decisions1

Directory of Open Access Journals (Sweden)

Steven M. Platek

2007-01-01

Full Text Available Sex differences in reaction to a romantic partner's infidelity are well documented and are hypothesized to be attributable to sex-specific jealousy mechanisms which are utilized to solve adaptive problems associated with risk of extra-pair copulation. Males, because of the risk of cuckoldry become more upset by sexual infidelity, while females, because of loss of resources and biparental investment tend to become more distressed by emotional infidelity. However, the degree to which these sex-specific reactions to jealousy interact with cues to kin are completely unknown. Here we investigated the interaction of facial resemblance with decisions about sex-specific jealousy scenarios. Fifty nine volunteers were asked to imagine that two different people (represented by facial composites informed them about their romantic partner's sexual or emotional infidelity. Consistent with previous research, males ranked sexual infidelity scenarios as most upsetting and females ranked emotional infidelity scenarios most upsetting. However, when information about the infidelity was provided by a face that resembled the subject, sex-specific reactions to jealousy were exaggerated. This finding highlights the use of facial resemblance as a putative self-referent phenotypic matching cue that impacts trusting behavior in sexual contexts.

Avaliação de diferentes materiais para recobrimento de camas em baias de galpão modelo free-stall

OpenAIRE

Cecchin, Daiane; Campos, Alessandro T.; Pires, Maria de F. A.; Lima, Renato R. de; Yanagi Junior, Tadayuki; Souza, Myriam C. M.

2014-01-01

Objetivou-se, com o presente trabalho, comparar o uso de cama de colchão de borracha e de areia no recobrimento da superfície de baias para confinamento tipo free-stall. Foram monitoradas 18 vacas holandesas confinadas em galpão modelo free-stall cujas baias foram recobertas com camas de areia e colchão de borracha (tratamentos). O delineamento experimental foi em blocos casualizados. Os parâmetros comportamentais estudados foram os tempos despendidos nas atividades: deitada em ócio e deitada...

Exploratory study of the effects of wing-leading-edge modifications on the stall/spin behavior of a light general aviation airplane

Science.gov (United States)

1979-01-01

Configurations with full-span and segmented leading-edge flaps and full-span and segmented leading-edge droop were tested. Studies were conducted with wind-tunnel models, with an outdoor radio-controlled model, and with a full-scale airplane. Results show that wing-leading-edge modifications can produce large effects on stall/spin characteristics, particularly on spin resistance. One outboard wing-leading-edge modification tested significantly improved lateral stability at stall, spin resistance, and developed spin characteristics.

Fluid mechanics of dynamic stall. II - Prediction of full scale characteristics

Science.gov (United States)

Ericsson, L. E.; Reding, J. P.

1988-01-01

Analytical extrapolations are made from experimental subscale dynamics to predict full scale characteristics of dynamic stall. The method proceeds by establishing analytic relationships between dynamic and static aerodynamic characteristics induced by viscous flow effects. The method is then validated by predicting dynamic test results on the basis of corresponding static test data obtained at the same subscale flow conditions, and the effect of Reynolds number on the static aerodynamic characteristics are determined from subscale to full scale flow conditions.

Prediction of H.A.W.T. blade stall and performance

Energy Technology Data Exchange (ETDEWEB)

Giannakidis, G.; Graham, J.M.R. [Imperial College, Dept. of Aeronautics, London (United Kingdom)

1996-09-01

A model is being developed for the prediction of Horizontal Axis Wind Turbine blade stall and performance coupled with a simple aeroelastic analysis model. For the aerodynamic calculation a two dimensional unsteady Navier-Stokes solver on a sectional basis on the blade is coupled with a three dimensional vortex lattice wake. Pressure coefficient distributions are calculated from the two dimensional viscous flow in each blade section. The aerodynamic computations are coupled with a vibrating beam model in order to incorporate flapwise deformations of the blade. (au) 17 refs.

Stall margin improvement of an axial flow fan with end wall injection and suction; Hekimen fukidashi suidashi ni yoru han'yo jikuryu sofuki no shissoku kaizen

Energy Technology Data Exchange (ETDEWEB)

Nishioka, K.; Kuroda, H.; Obata, S.; Chimura, O. [National Defense Academy, Kanagawa (Japan)

1999-06-25

The experimental studies are conducted to reveal the mechanism of stall margin improvement of an axial flow fan by injection or suction from the end wall. In case of injection, the largest improvement is obtained by the injection at about 0. 14 {approx} 0 .21 times axial chord length downstream from leading edge. The reason for large improvement is that stall vortex, shed intermittent separation vortex and tip leakage vortex are dissipated by this injection, and also that this blowing suppresses the separation of boundary layer. In case of suction, the largest improvement is found for the suction from the end wall near leading edge. The amplitude of periodic static pressure after stall inception becomes smaller in comparison with injection cases. These effects are increased with the increase of suction flow rate, because the discharge of the vortex occurs more easily. On the other hand, the suction from the upstream of leading edge reduces the axial velocity near rotor tip, and then it induces stall. Also we tried to visualize the tip region flow, The suppression mechanism is discussed based on the visualization. The suppression of stall is successfully photographed. (author)

Visualization and image analysis of dynamic stall phenomenon for a Darrieus wind turbine; Darrieus fusha ni okeru doteki shissoku gensho no kashika to gazo kaisekini kansuru kenkyu

Energy Technology Data Exchange (ETDEWEB)

Fujisawa, N.; Shibuya, S.; Takano, T. [Niigata University, Niigata (Japan)

1999-10-25

The flow field around a Darrieus wind turbine is studied by flow visualization and PIV measurement in a rotating frame of reference to understand the unsteady nature of dynamic stall appearing at low tip-speed ratios. The qualitative nature of the dynamic stall observed by the flow visualization using dye injection technique is quantitatively reproduced in the instantaneous velocity distributions around the blade measured by PIV technique. These results indicate that two pairs of stall vortices are generated in one cycle of the turbine rotation and they grow in size as the tip-speed ratio decreases. The mechanism of the dynamic stall is found to be due to the flow separation over the suction side of the blade followed by the generation of in-flow motion from the pressure side to the suction side of the blade through the trailing edge. (author)

Traumatic bone cyst resembling apical periodontitis.

Science.gov (United States)

Rosen, D J; Ardekian, L; Machtei, E E; Peled, M; Manor, R; Laufer, D

1997-10-01

Among the pseudocysts of the jaws, the traumatic bone cyst is known as an asymptomatic lesion often noted unintentionally during routine radiographic examinations. The lesion neither devitalizes the teeth within its borders, nor does it cause resorption of their roots. The well-demarcated traumatic bone cyst often projects into the intraradicular septa and hence has been described as having scalloped borders. The following presentation is of a traumatic bone cyst that resembled periodontal pathology in its appearance.

RANS study of unsteady flow around a profile blade : application to stall of horizontal axis wind turbine

Energy Technology Data Exchange (ETDEWEB)

Belkheir, N. [Khemis Miliana Univ., Ain Defla (Algeria); Dizene, R. [Univ. des Sciences et de la Technologie Houari Boumediene, Algiers (Algeria). Laboratoire de Mecanique Avancee; Khelladi, S.; Massouh, F.; Dobrev, I. [Arts et Metiers Paris Tech., Paris (France)

2010-07-01

The shape of an airfoil is designed to achieve the best aerodynamic performance. An aerofoil section undergoes dynamic stall when subjected to any form of unsteady angle of pitch. The study of a horizontal-axis wind turbine (HAWT) under wind operating conditions is complex because it is subject to instantaneous speed and wind direction variation. When turbine blades are driven into a dynamic stall, the lift coefficient drops suddenly resulting in a degradation in aerodynamic performance. This study presented steady and unsteady wind load predictions over an oscillating S809 airfoil tested in a subsonic wind tunnel. A model of sinusoidal pitch oscillations was used. The values for the angles of attack in steady state ranged from -20 to +40 degrees. The model considered 3 frequencies and 2 amplitudes. The two-dimensional numerical model simulated the instantaneous change of wind direction with respect to the turbine blade. Results were compared with data measurements of S809 aerofoil. Reasonable deviations were obtained between the predicted and experimental results for pitch oscillations. The URANS approach was used to predict the stall while the software FLUENT was used for the numerical solution. It was concluded that the behaviour of the unsteady flow in the wind farm must be considered in order to obtain an accurate estimate of the wind turbine aerodynamic load. 12 refs., 5 figs.

Numerical study on a single bladed vertical axis wind turbine under dynamic stall

Energy Technology Data Exchange (ETDEWEB)

Bangga, Galih [Institute of Aerodynamics and Gas Dynamics, University of Stuttgart, Stuttgart (Germany); Hutomo, Go; Sasongko, Herman [Dept. of Mechanical Engineering, Institut Teknologi Sepuluh Nopember, Surabaya (Indonesia); Wiranegara, Raditya [School of Mechanical Aerospace and Civil Engineering, University of Manchester, Manchester (United Kingdom)

2017-01-15

The aim of this study is to investigate the flow development of a single bladed vertical axis wind turbine using Computational fluid dynamics (CFD) methods. The blade is constructed using the NACA 0012 profile and is operating under stalled conditions at tip speed ratio of 2. Two dimensional simulations are performed using a commercial CFD package, ANSYS Fluent 15.0, employing the Menter-SST turbulence model. For the preliminary study, simulations of the NACA 0012 airfoil under static conditions are carried out and compared with available measurement data and calculations using the boundary layer code XFOIL. The CFD results under the dynamic case are presented and the resulting aerodynamic forces are evaluated. The turbine is observed to generate negative power at certain azimuth angles which can be divided into three main zones. The blade vortex interaction is observed to strongly influence the flow behavior near the blade and contributes to the power production loss. However, the impact is considered small since it covers only 6.4 % of the azimuth angle range where the power is negative compared to the dynamic stall impact which covers almost 22 % of the azimuth angle range.

Blade tip, finite aspect ratio, and dynamic stall effects on the Darrieus rotor

Science.gov (United States)

Paraschivoiu, I.; Desy, P.; Masson, C.

1988-02-01

The objective of the work described in this paper was to apply the Boeing-Vertol dynamic stall model in an asymmetric manner to account for the asymmetry of the flow between the left and right sides of the rotor. This phenomenon has been observed by the flow visualization of a two-straight-bladed Darrieus rotor in the IMST water tunnel. Also introduced into the aerodynamic model are the effects of the blade tip and finite aspect ratio on the aerodynamic performance of the Darrieus wind turbine. These improvements are compatible with the double-multiple-streamtube model and have been included in the CARDAAV computer code for predicting the aerodynamic performance. Very good agreement has been observed between the test data (Sandia 17 m) and theoretical predictions; a significant improvement over the previous dynamic stall model was obtained for the rotor power at low tip speed ratios, while the inclusion of the finite aspect ratio effects enhances the prediction of the rotor power for high tip speed ratios. The tip losses and finite aspect ratio effects were also calculated for a small-scale vertical-axis wind turbine, with a two-straight-bladed (NACA 0015) rotor.

Grid support of a wind farm with active stall wind turbines and AC grid connection

DEFF Research Database (Denmark)

Hansen, Anca Daniela; Sørensen, Poul Ejnar; Iov, F.

2006-01-01

grid connection. The designed control system has the task of enabling such a wind farm to provide the best grid support. It is based on two control levels: a supervisory control level, which controls the power production of the whole farm by sending out reference signals to each individual wind turbine......One of the main concerns in the grid integration of large wind farms is their ability to behave as active controllable components in the power system. This article presents the design of a new integrated power control system for a wind farm made up exclusively of active stall wind turbines with AC......, and a local control level, which ensures that the reference power signals at the wind turbine level are reached. The ability of active stall wind farms with AC grid connection to control the power production to the reference power ordered by the operators is assessed and discussed by means of simulations....

Wake structure of a single vertical axis wind turbine

International Nuclear Information System (INIS)

Posa, Antonio; Parker, Colin M.; Leftwich, Megan C.; Balaras, Elias

2016-01-01

Highlights: • The wake structure of an isolated Vertical Axis Wind Turbine is studied by both Particle Imaging Velocimetry and Large Eddy Simulation. • The wake structure is investigated for two values of tip speed ratio, TSR_1=1.35 and TSR_2=2.21. • A displacement of the momentum deficit towards the windward side is verified in the wake. • Higher turbulence and coherence is observed on the leeward side of the wake, due to the upwind stall of the blades. • Coherence in the wake core, associated to the downwind stall, decays quickly downstream. - Abstract: The wake structure behind a vertical axis wind turbine (VAWT) is both measured in a wind tunnel using particle imaging velocimetry (PIV) and computed with large-eddy simulation (LES). Geometric and dynamic conditions are closely matched to typical applications of VAWTs (Re_D ∼ 1.8 × 10"5). The experiments and computations were highly coordinated with continuous two-way feedback to produce the most insightful results. Good qualitative agreement is seen between the computational and experimental results. The dependence of the wake structure on the tip speed ratio, TSR, is investigated, showing higher asymmetry and larger vortices at the lower rotational speed, due to stronger dynamic stall phenomena. Instantaneous, ensemble-averaged and phase-averaged fields are discussed, as well as the dynamics of coherent structures in the rotor region and downstream wake.

Dynamic stall study of a multi-element airfoil

Science.gov (United States)

Tung, Chee; Mcalister, Kenneth W.; Wang, Clin M.

1992-01-01

Unsteady flow behavior and load characteristics of a VR-7 airfoil with and without a slat were studied in the water tunnel of the Aeroflightdynamics Directorate, NASA Ames Research Center. Both airfoils were oscillated sinusoidally between 5 and 25 degrees at a Reynolds number of 200,000 to obtain the unsteady lift, drag and pitching moment data. A fluorescing dye was released from an orifice located at the leading edge of the airfoil for the purpose of visualizing the boundary layer and wake flow. The flow field and load predictions of an incompressible Navier-Stokes code based on a velocity-vorticity formulation were compared with the test data. The test and predictions both confirm that the slatted VR-7 airfoil delays both static and dynamic stall as compared to the VR-7 airfoil alone.

Proposed Chevron Tengiz venture stalls amid Soviet political squabble

International Nuclear Information System (INIS)

Anon.

1991-01-01

This paper reports on the status of foreign investment in Soviet oil and gas joint ventures which has reached a critical juncture. Just as the U.S. is considering granting most favored nation trade status to the U.S.S.R., the joint venture petroleum deal seen as the litmus test for such deals-Chevron Corp.'s proposed addition of supergiant Tengiz oil field to its Caspian Sea joint venture-has stalled amid controversy. Unconfirmed reports from Soviet officials and other foreign joint venture participants in the U.S.S.R. have Chevron pulling out of the long negotiated, multibillion dollar project after the Soviets rejected the company's terms. Chevron, however, insists the project is still alive

Pareidolia in Neuroendocrinology: A Pituitary Macroadenoma Resembling "Big Bird".

Science.gov (United States)

de Herder, Wouter W

2016-04-01

The MRI picture of a pituitary macroadenoma with supra- and perisellar expansion resembled a famous character from a children's television series demonstrating that pareidolia is also observed in neuro-endocrinology and -radiology.

Fathers see stronger family resemblances than non-fathers in unrelated children's faces.

Science.gov (United States)

Bressan, Paola; Dal Pos, Stefania

2012-12-01

Even after they have taken all reasonable measures to decrease the probability that their spouses cheat on them, men still face paternal uncertainty. Such uncertainty can lead to paternal disinvestment, which reduces the children's probability to survive and reproduce, and thus the reproductive success of the fathers themselves. A theoretical model shows that, other things being equal, men who feel confident that they have fathered their spouses' offspring tend to enjoy greater fitness (i.e., leave a larger number of surviving progeny) than men who do not. This implies that fathers should benefit from exaggerating paternal resemblance. We argue that the self-deceiving component of this bias could be concealed by generalizing this resemblance estimation boost to (1) family pairs other than father-child and (2) strangers. Here, we tested the prediction that fathers may see, in unrelated children's faces, stronger family resemblances than non-fathers. In Study 1, 70 men and 70 women estimated facial resemblances between children paired, at three different ages (as infants, children, and adolescents), either to themselves or to their parents. In Study 2, 70 men and 70 women guessed the true parents of the same children among a set of adults. Men who were fathers reported stronger similarities between faces than non-fathers, mothers, and non-mothers did, but were no better at identifying childrens' real parents. We suggest that, in fathers, processing of facial resemblances is biased in a manner that reflects their (adaptive) wishful thinking that fathers and children are related.

Age and Gender Differences in Facial Attractiveness, but Not Emotion Resemblance, Contribute to Age and Gender Stereotypes

Directory of Open Access Journals (Sweden)

Rocco Palumbo

2017-09-01

Full Text Available Considerable research has shown effects of facial appearance on trait impressions and group stereotypes. We extended those findings in two studies that investigated the contribution of resemblance to emotion expressions and attractiveness to younger adults (YA and older adults (OA age and gender stereotypes on the dimensions of warmth and competence. Using connectionist modeling of facial metrics of 240 neutral younger and older faces, Study 1 found that, neutral expression older faces or female faces showed greater structural resemblance to happy expressions and less resemblance to angry expressions than did younger or male faces, respectively. In addition, neutral female faces showed greater resemblance to surprise expressions. In Study 2, YA and OA rated the faces of Study 1 for attractiveness and for 4 traits that we aggregated on the dimensions of competence (competent, healthy and warmth (trustworthy, not shrewd. We found that YA, but not OA, age stereotypes replicated previous research showing higher perceived warmth and lower perceived competence in older adults. In addition, previously documented gender stereotypes were moderated by face age for both YA and OA. The greater attractiveness of younger than older faces and female than male faces influenced age and gender stereotypes, including these deviations from prior research findings using category labels rather than faces. On the other hand, face age and face sex differences in emotion resemblance did not influence age or gender stereotypes, contrary to prediction. Our results provide a caveat to conclusions about age and gender stereotypes derived from responses to category labels, and they reveal the importance of assessing stereotypes with a methodology that is sensitive to influences of group differences in appearance that can exacerbate or mitigate stereotypes in more ecologically valid contexts. Although the gender differences in attractiveness in the present study may not have

Age and Gender Differences in Facial Attractiveness, but Not Emotion Resemblance, Contribute to Age and Gender Stereotypes.

Science.gov (United States)

Palumbo, Rocco; Adams, Reginald B; Hess, Ursula; Kleck, Robert E; Zebrowitz, Leslie

2017-01-01

Considerable research has shown effects of facial appearance on trait impressions and group stereotypes. We extended those findings in two studies that investigated the contribution of resemblance to emotion expressions and attractiveness to younger adults (YA) and older adults (OA) age and gender stereotypes on the dimensions of warmth and competence. Using connectionist modeling of facial metrics of 240 neutral younger and older faces, Study 1 found that, neutral expression older faces or female faces showed greater structural resemblance to happy expressions and less resemblance to angry expressions than did younger or male faces, respectively. In addition, neutral female faces showed greater resemblance to surprise expressions. In Study 2, YA and OA rated the faces of Study 1 for attractiveness and for 4 traits that we aggregated on the dimensions of competence (competent, healthy) and warmth (trustworthy, not shrewd). We found that YA, but not OA, age stereotypes replicated previous research showing higher perceived warmth and lower perceived competence in older adults. In addition, previously documented gender stereotypes were moderated by face age for both YA and OA. The greater attractiveness of younger than older faces and female than male faces influenced age and gender stereotypes, including these deviations from prior research findings using category labels rather than faces. On the other hand, face age and face sex differences in emotion resemblance did not influence age or gender stereotypes, contrary to prediction. Our results provide a caveat to conclusions about age and gender stereotypes derived from responses to category labels, and they reveal the importance of assessing stereotypes with a methodology that is sensitive to influences of group differences in appearance that can exacerbate or mitigate stereotypes in more ecologically valid contexts. Although the gender differences in attractiveness in the present study may not have generalizability

Validation of an Actuator Line Model Coupled to a Dynamic Stall Model for Pitching Motions Characteristic to Vertical Axis Turbines

International Nuclear Information System (INIS)

Mendoza, Victor; Goude, Anders; Bachant, Peter; Wosnik, Martin

2016-01-01

Vertical axis wind turbines (VAWT) can be used to extract renewable energy from wind flows. A simpler design, low cost of maintenance, and the ability to accept flow from all directions perpendicular to the rotor axis are some of the most important advantages over conventional horizontal axis wind turbines (HAWT). However, VAWT encounter complex and unsteady fluid dynamics, which present significant modeling challenges. One of the most relevant phenomena is dynamic stall, which is caused by the unsteady variation of angle of attack throughout the blade rotation, and is the focus of the present study. Dynamic stall is usually used as a passive control for VAWT operating conditions, hence the importance of predicting its effects. In this study, a coupled model is implemented with the open-source CFD toolbox OpenFOAM for solving the Navier-Stokes equations, where an actuator line model and dynamic stall model are used to compute the blade loading and body force. Force coefficients obtained from the model are validated with experimental data of pitching airfoil in similar operating conditions as an H-rotor type VAWT. Numerical results show reasonable agreement with experimental data for pitching motion. (paper)

Validation of an Actuator Line Model Coupled to a Dynamic Stall Model for Pitching Motions Characteristic to Vertical Axis Turbines

Science.gov (United States)

Mendoza, Victor; Bachant, Peter; Wosnik, Martin; Goude, Anders

2016-09-01

Vertical axis wind turbines (VAWT) can be used to extract renewable energy from wind flows. A simpler design, low cost of maintenance, and the ability to accept flow from all directions perpendicular to the rotor axis are some of the most important advantages over conventional horizontal axis wind turbines (HAWT). However, VAWT encounter complex and unsteady fluid dynamics, which present significant modeling challenges. One of the most relevant phenomena is dynamic stall, which is caused by the unsteady variation of angle of attack throughout the blade rotation, and is the focus of the present study. Dynamic stall is usually used as a passive control for VAWT operating conditions, hence the importance of predicting its effects. In this study, a coupled model is implemented with the open-source CFD toolbox OpenFOAM for solving the Navier-Stokes equations, where an actuator line model and dynamic stall model are used to compute the blade loading and body force. Force coefficients obtained from the model are validated with experimental data of pitching airfoil in similar operating conditions as an H-rotor type VAWT. Numerical results show reasonable agreement with experimental data for pitching motion.

Bifurcation Analysis with Aerodynamic-Structure Uncertainties by the Nonintrusive PCE Method

Directory of Open Access Journals (Sweden)

Linpeng Wang

2017-01-01

Full Text Available An aeroelastic model for airfoil with a third-order stiffness in both pitch and plunge degree of freedom (DOF and the modified Leishman–Beddoes (LB model were built and validated. The nonintrusive polynomial chaos expansion (PCE based on tensor product is applied to quantify the uncertainty of aerodynamic and structure parameters on the aerodynamic force and aeroelastic behavior. The uncertain limit cycle oscillation (LCO and bifurcation are simulated in the time domain with the stochastic PCE method. Bifurcation diagrams with uncertainties were quantified. The Monte Carlo simulation (MCS is also applied for comparison. From the current work, it can be concluded that the nonintrusive polynomial chaos expansion can give an acceptable accuracy and have a much higher calculation efficiency than MCS. For aerodynamic model, uncertainties of aerodynamic parameters affect the aerodynamic force significantly at the stage from separation to stall at upstroke and at the stage from stall to reattach at return. For aeroelastic model, both uncertainties of aerodynamic parameters and structure parameters impact bifurcation position. Structure uncertainty of parameters is more sensitive for bifurcation. When the nonlinear stall flutter and bifurcation are concerned, more attention should be paid to the separation process of aerodynamics and parameters about pitch DOF in structure.

Optimal parameters for the FFA-Beddoes dynamic stall model

Energy Technology Data Exchange (ETDEWEB)

Bjoerck, A; Mert, M [FFA, The Aeronautical Research Institute of Sweden, Bromma (Sweden); Madsen, H A [Risoe National Lab., Roskilde (Denmark)

1999-03-01

Unsteady aerodynamic effects, like dynamic stall, must be considered in calculation of dynamic forces for wind turbines. Models incorporated in aero-elastic programs are of semi-empirical nature. Resulting aerodynamic forces therefore depend on values used for the semi-empiricial parameters. In this paper a study of finding appropriate parameters to use with the Beddoes-Leishman model is discussed. Minimisation of the `tracking error` between results from 2D wind tunnel tests and simulation with the model is used to find optimum values for the parameters. The resulting optimum parameters show a large variation from case to case. Using these different sets of optimum parameters in the calculation of blade vibrations, give rise to quite different predictions of aerodynamic damping which is discussed. (au)

Phosphorylated RPA recruits PALB2 to stalled DNA replication forks to facilitate fork recovery.

Science.gov (United States)

Murphy, Anar K; Fitzgerald, Michael; Ro, Teresa; Kim, Jee Hyun; Rabinowitsch, Ariana I; Chowdhury, Dipanjan; Schildkraut, Carl L; Borowiec, James A

2014-08-18

Phosphorylation of replication protein A (RPA) by Cdk2 and the checkpoint kinase ATR (ATM and Rad3 related) during replication fork stalling stabilizes the replisome, but how these modifications safeguard the fork is not understood. To address this question, we used single-molecule fiber analysis in cells expressing a phosphorylation-defective RPA2 subunit or lacking phosphatase activity toward RPA2. Deregulation of RPA phosphorylation reduced synthesis at forks both during replication stress and recovery from stress. The ability of phosphorylated RPA to stimulate fork recovery is mediated through the PALB2 tumor suppressor protein. RPA phosphorylation increased localization of PALB2 and BRCA2 to RPA-bound nuclear foci in cells experiencing replication stress. Phosphorylated RPA also stimulated recruitment of PALB2 to single-strand deoxyribonucleic acid (DNA) in a cell-free system. Expression of mutant RPA2 or loss of PALB2 expression led to significant DNA damage after replication stress, a defect accentuated by poly-ADP (adenosine diphosphate) ribose polymerase inhibitors. These data demonstrate that phosphorylated RPA recruits repair factors to stalled forks, thereby enhancing fork integrity during replication stress. © 2014 Murphy et al.

Flow-around modes for a rhomboid wing with a stall vortex in the shock layer

Science.gov (United States)

Zubin, M. A.; Maximov, F. A.; Ostapenko, N. A.

2017-12-01

The results of theoretical and experimental investigation of an asymmetrical hypersonic flow around a V-shaped wing with the opening angle larger than π on the modes with attached shockwaves on forward edges, when the stall flow is implemented on the leeward wing cantilever behind the kink point of the cross contour. In this case, a vortex of nonviscous nature is formed in which the velocities on the sphere exceeding the speed of sound and resulting in the occurrence of pressure shocks with an intensity sufficient for the separation of the turbulent boundary layer take place in the reverse flow according to the calculations within the framework of the ideal gas. It is experimentally established that a separation boundary layer can exist in the reverse flow, and its structure is subject to the laws inherent to the reverse flow in the separation region of the turbulent boundary layer arising in the supersonic conic flow under the action of a shockwave incident to the boundary layer.

Stall/surge dynamics of a multi-stage air compressor in response to a load transient of a hybrid solid oxide fuel cell-gas turbine system

Science.gov (United States)

Azizi, Mohammad Ali; Brouwer, Jacob

2017-10-01

A better understanding of turbulent unsteady flows in gas turbine systems is necessary to design and control compressors for hybrid fuel cell-gas turbine systems. Compressor stall/surge analysis for a 4 MW hybrid solid oxide fuel cell-gas turbine system for locomotive applications is performed based upon a 1.7 MW multi-stage air compressor. Control strategies are applied to prevent operation of the hybrid SOFC-GT beyond the stall/surge lines of the compressor. Computational fluid dynamics tools are used to simulate the flow distribution and instabilities near the stall/surge line. The results show that a 1.7 MW system compressor like that of a Kawasaki gas turbine is an appropriate choice among the industrial compressors to be used in a 4 MW locomotive SOFC-GT with topping cycle design. The multi-stage radial design of the compressor enhances the ability of the compressor to maintain air flow rate during transient step-load changes. These transient step-load changes are exhibited in many potential applications for SOFC/GT systems. The compressor provides sustained air flow rate during the mild stall/surge event that occurs due to the transient step-load change that is applied, indicating that this type of compressor is well-suited for this hybrid application.

Power reduction and the radial limit of stall delay in revolving wings of different aspect ratio

NARCIS (Netherlands)

Kruyt, J.W.; Heijst, Van G.F.; Altshuler, D.L.; Lentink, David

2015-01-01

Airplanes and helicopters use high aspect ratio wings to reduce the power required to fly, but must operate at low angle of attack to prevent flow separation and stall. Animals capable of slow sustained flight, such as hummingbirds, have low aspect ratio wings and flap their wings at high angle

Aerodynamic loads calculation and analysis for large scale wind turbine based on combining BEM modified theory with dynamic stall model

Energy Technology Data Exchange (ETDEWEB)

Dai, J.C. [College of Mechanical and Electrical Engineering, Central South University, Changsha (China); School of Electromechanical Engineering, Hunan University of Science and Technology, Xiangtan (China); Hu, Y.P.; Liu, D.S. [School of Electromechanical Engineering, Hunan University of Science and Technology, Xiangtan (China); Long, X. [Hara XEMC Windpower Co., Ltd., Xiangtan (China)

2011-03-15

The aerodynamic loads for MW scale horizontal-axis wind turbines are calculated and analyzed in the established coordinate systems which are used to describe the wind turbine. In this paper, the blade element momentum (BEM) theory is employed and some corrections, such as Prandtl and Buhl models, are carried out. Based on the B-L semi-empirical dynamic stall (DS) model, a new modified DS model for NACA63-4xx airfoil is adopted. Then, by combing BEM modified theory with DS model, a set of calculation method of aerodynamic loads for large scale wind turbines is proposed, in which some influence factors such as wind shear, tower, tower and blade vibration are considered. The research results show that the presented dynamic stall model is good enough for engineering purpose; the aerodynamic loads are influenced by many factors such as tower shadow, wind shear, dynamic stall, tower and blade vibration, etc, with different degree; the single blade endures periodical changing loads but the variations of the rotor shaft power caused by the total aerodynamic torque in edgewise direction are very small. The presented study approach of aerodynamic loads calculation and analysis is of the university, and helpful for thorough research of loads reduction on large scale wind turbines. (author)

Analysis of Vaneless Diffuser Stall Instability in a Centrifugal Compressor

Directory of Open Access Journals (Sweden)

Elias Sundström

2017-11-01

Full Text Available Numerical simulations based on the large eddy simulation approach were conducted with the aim to explore vaneless diffuser rotating stall instability in a centrifugal compressor. The effect of the impeller blade passage was included as an inlet boundary condition with sufficiently low flow angle relative to the tangent to provoke the instability and cause circulation in the diffuser core flow. Flow quantities, velocity and pressure, were extracted to accumulate statistics for calculating mean velocity and mean Reynolds stresses in the wall-to-wall direction. The paper focuses on the assessment of the complex response of the system to the velocity perturbations imposed, the resulting pressure gradient and flow curvature effects.

Multiple ureterolithiasis resembling steinstrasse: An unusual presentation

Directory of Open Access Journals (Sweden)

Praveen Kumar Pandey

2014-12-01

Full Text Available Steinstrasse or “stone street” is an expected complication after extracorporeal shock wave lithotripsy in patients with high stone burden. However, there are published reports of multiple ureterolithiasis resembling steinstrasse in patients with distal renal tubular acidosis. Here we report an uncommon case of a 60-year-old woman who presented with right renal calculi. Her right ureter was studded with multiple calculi up to the vesicoureteric junction. The affected right kidney was nonfunctional and was managed by nephroureterectomy.

Simulation model of a transient fault controller for an active-stall wind turbine

Energy Technology Data Exchange (ETDEWEB)

Jauch, C.; Soerensen, P.; Bak Jensen, B.

2005-01-01

This paper describes the simulation model of a controller that enables an active-stall wind turbine to ride through transient faults. The simulated wind turbine is connected to a simple model of a power system. Certain fault scenarios are specified and the turbine shall be able to sustain operation in case of such faults. The design of the controller is described and its performance assessed by simulations. The control strategies are explained and the behaviour of the turbine discussed. (author)

Active unsteady aerodynamic suppression of rotating stall in an incompressible flow centrifugal compressor with vaned diffuser

Science.gov (United States)

Lawless, Patrick B.; Fleeter, Sanford

1991-01-01

A mathematical model is developed to analyze the suppression of rotating stall in an incompressible flow centrifugal compressor with a vaned diffuser, thereby addressing the important need for centrifugal compressor rotating stall and surge control. In this model, the precursor to to instability is a weak rotating potential velocity perturbation in the inlet flow field that eventually develops into a finite disturbance. To suppress the growth of this potential disturbance, a rotating control vortical velocity disturbance is introduced into the impeller inlet flow. The effectiveness of this control is analyzed by matching the perturbation pressure in the compressor inlet and exit flow fields with a model for the unsteady behavior of the compressor. To demonstrate instability control, this model is then used to predict the control effectiveness for centrifugal compressor geometries based on a low speed research centrifugal compressor. These results indicate that reductions of 10 to 15 percent in the mean inlet flow coefficient at instability are possible with control waveforms of half the magnitude of the total disturbance at the inlet.

Allergic Contact Dermatitis to Benzoyl Peroxide Resembling Impetigo.

Science.gov (United States)

Kim, Changhyun; Craiglow, Brittany G; Watsky, Kalman L; Antaya, Richard J

2015-01-01

A 17-year-old boy presented with recurring severe dermatitis of the face of 5-months duration that resembled impetigo. He had been treated with several courses of antibiotics without improvement. Biopsy showed changes consistent with allergic contact dermatitis and patch testing later revealed sensitization to benzoyl peroxide, which the patient had been using for the treatment of acne vulgaris. © 2015 Wiley Periodicals, Inc.

A Beddoes-Leishman type dynamic stall model in state-space and indicial formulations[Wind turbines

Energy Technology Data Exchange (ETDEWEB)

Hansen, M.H.; Gaunaa, M.; Aagaard Madsen, H.

2004-06-01

This report contains a description of a Beddoes-Leishman type dynamic stall model in both a state-space and an indicial function formulation. The m odel predicts the unsteady aerodynamic foreces and moment on an airfoil section undergoing arbitrary motion in heavy, lead-lag, and pitch. The model includes the effects of shed vorticity from the trailing edge (Theodorsen Theory), and the effects of an instationary trailing edge separation point. The governing equations of the model are nonlinear, and they are linearized about a steady state for application in stability analyzes. A validation is carried out by comparing the response of the model with inviscid solutions and observing the general behavior of the model using known airfoil data as input. The proposed dyanmic model gives results identical to inviscid solutions within the attached-flow region; and it exhibits the expected dynamic features, such as overshoot of the lift, in the stall region. The linearized model is shown to give identical results to the full model for small amplitude oscillations. furthermore, it is shown that the response of finite thickness airfoils can be reproduced to a high accuracy by the use of specific inviscid response functions. (au)

Effects of parenting quality on adolescents' personality resemblance to their parents. The TRAILS study.

Science.gov (United States)

Langenhof, M Rohaa; Komdeur, Jan; Oldehinkel, Albertine J

2016-08-01

This study considers the development of resemblance between 741 adolescents and their biological parents, across six NEO-PI-R personality traits known to be important in psychological problems: anger-hostility, impulsiveness, vulnerability, assertiveness, excitement-seeking, and self-discipline. We modelled the association between perceived parental warmth and rejection at age eleven and personality resemblance to parents at about age sixteen. Parenting experienced during early adolescence was related to the degree and direction in which adolescents resembled their parents five years later in life. Rejection, especially from fathers, significantly predicted a smaller resemblance to both the parents. Girls were more strongly affected by parental quality than boys, and there was some indication that adolescents responded in opposite ways to parenting from mothers and fathers. This study is a first step in uncovering the complex interplay between parenting, gender, and the current generation's ability to develop personality traits independent from the previous generation. Copyright © 2016 The Foundation for Professionals in Services for Adolescents. Published by Elsevier Ltd. All rights reserved.

Familial Resemblance in Dietary Intakes of Children, Adolescents, and Parents

DEFF Research Database (Denmark)

Bogl, Leonie H.; Silventoinen, Karri; Hebestreit, Antje

2017-01-01

Information on familial resemblance is important for the design of effective family-based interventions. We aimed to quantify familial correlations and estimate the proportion of variation attributable to genetic and shared environmental effects (i.e., familiality) for dietary intake variables an...

Archaic artifacts resembling celestial spheres

Science.gov (United States)

Dimitrakoudis, S.; Papaspyrou, P.; Petoussis, V.; Moussas, X.

We present several bronze artifacts from the Archaic Age in Greece (750-480 BC) that resemble celestial spheres or forms of other astronomical significance. They are studied in the context of the Dark Age transition from Mycenaean Age astronomical themes to the philosophical and practical revival of astronomy in the Classical Age with its plethora of astronomical devices. These artifacts, mostly votive in nature are spherical in shape and appear in a variety of forms their most striking characteristic being the depiction of meridians and/or an equator. Most of those artifacts come from Thessaly, and more specifically from the temple of Itonia Athena at Philia, a religious center of pan-Hellenic significance. Celestial spheres, similar in form to the small artifacts presented in this study, could be used to measure latitudes, or estimate the time at a known place, and were thus very useful in navigation.

Partners in health? Exploring resemblance in health between partners in married and cohabiting couples.

Science.gov (United States)

Monden, Christiaan

2007-04-01

Sociological theories on family formation and families and health suggest that married and cohabiting partners will resemble each other in health status, positively or negatively. The family is often seen as a health-enhancing agent for individuals. However, there are large health differences among families. This study aims to answer the question whether it is the case that the healthy live with the healthy and individuals with poor health have partners who are also in poor health. Moreover, it examines whether resemblance in health is a consequence of partner choice--educational homogamy in particular--behaviour or shared circumstances. Younger and older couples are compared to investigate whether health resemblance increases over the lifecourse. Analyses of a nationally representative sample of almost 12,000 Dutch couples show that partners are indeed significantly alike with regard to several health indicators. Respondents whose partner reports poor health are almost three times more likely to report poor health than respondents whose partner is in good health. There is a strong accumulation of health problems within households. Partner selection with regard to education causes part of the partner resemblance in health. Less support is found for the hypotheses that risk behaviour, mutual influence or the effects of shared circumstances cause similarity between partners' health status. Surprisingly, partners in older couples, who have been together for a longer time, do not resemble each other significantly more than partners in younger couples. The implications of these findings for sociological theory and social inequalities in health are discussed.

The Texas Adoption Project: adopted children and their intellectual resemblance to biological and adoptive parents.

Science.gov (United States)

Horn, J M

1983-04-01

Intelligence test scores were obtained from parents and children in 300 adoptive families and compared with similar measures available for the biological mothers of the same adopted children. Results supported the hypothesis that genetic variability is an important influence in the development of individual differences for intelligence. The most salient finding was that adopted children resemble their biological mothers more than they resemble the adoptive parents who reared them from birth. A small subset of the oldest adopted children did not resemble their biological mothers. The suggestion that the influence of genes declines with age is treated with caution since other adoption studies report a trend in the opposite direction.

The challenge of unravelling family resemblance related to illness behaviour.

NARCIS (Netherlands)

Cardol, M.; Groenewegen, P.P.; Spreeuwenberg, P.; Dijk, L. van; Bosch, W. van den; Bakker, D.H. de

2005-01-01

Background: Efforts to promote health or prevent disease may conflict with patients’ habits at home. Irrespective of the national setting, families are important social contexts in which illness occurs and resolves. Family members resemble each other in their illness behaviour, even across

A stochastic model for the simulation of wind turbine blades in static stall

DEFF Research Database (Denmark)

Bertagnolio, Franck; Rasmussen, Flemming; Sørensen, Niels N.

2010-01-01

The aim of this work is to improve aeroelastic simulation codes by accounting for the unsteady aerodynamic forces that a blade experiences in static stall. A model based on a spectral representation of the aerodynamic lift force is defined. The drag and pitching moment are derived using...... a conditional simulation technique for stochastic processes. The input data for the model can be collected either from measurements or from numerical results from a Computational Fluid Dynamics code for airfoil sections at constant angles of attack. An analysis of such data is provided, which helps to determine...

Suppression of dynamic stall with a leading-edge slat on a VR-7 airfoil

Science.gov (United States)

Mcalister, K. W.; Tung, C.

1993-01-01

The VR-7 airfoil was experimentally studied with and without a leading-edge slat at fixed angles of attack from 0 deg to 30 deg at Re = 200,000 and for unsteady pitching motions described by alpha equals alpha(sub m) + 10 deg(sin(wt)). The models were two dimensional, and the test was performed in a water tunnel at Ames Research Center. The unsteady conditions ranged over Re equals 100,000 to 250,000, k equals 0.001 to 0.2, and alpha(sub m) = 10 deg to 20 deg. Unsteady lift, drag, and pitching-moment measurements were obtained along with fluorescent-dye flow visualizations. The addition of the slat was found to delay the static-drag and static-moment stall by about 5 degrees and to eliminate completely the development of a dynamic-stall vortex during unsteady motions that reached angles as high as 25 degrees. In all of the unsteady cases studied, the slat caused a significant reduction in the force and moment hysteresis amplitudes. The reduced frequency was found to have the greatest effect on the results, whereas the Reynolds number had little effect on the behavior of either the basic or the slatted airfoil. The slat caused a slight drag penalty at low angles of attack, but generally increased the lift/drag ratio when averaged over the full cycle of oscillation.

Experimental Methods Applied in a Study of Stall Flutter in an Axial Flow Fan

Directory of Open Access Journals (Sweden)

John D. Gill

2004-01-01

Full Text Available Flutter testing is an integral part of aircraft gas turbine engine development. In typical flutter testing blade mounted sensors in the form of strain gages and casing mounted sensors in the form of light probes (NSMS are used. Casing mounted sensors have the advantage of being non-intrusive and can detect the vibratory response of each rotating blade. Other types of casing mounted sensors can also be used to detect flutter of rotating blades. In this investigation casing mounted high frequency response pressure transducers are used to characterize the part-speed stall flutter response of a single stage unshrouded axial-flow fan. These dynamic pressure transducers are evenly spaced around the circumference at a constant axial location upstream of the fan blade leading edge plane. The pre-recorded experimental data at 70% corrected speed is analyzed for the case where the fan is back-pressured into the stall flutter zone. The experimental data is analyzed using two probe and multi-probe techniques. The analysis techniques for each method are presented. Results from these two analysis methods indicate that flutter occurred at a frequency of 411 Hz with a dominant nodal diameter of 2. The multi-probe analysis technique is a valuable method that can be used to investigate the initiation of flutter in turbomachines.

Compliance with NAGCAT work practices recommendations for youth cleaning service alleys in stall barns.

Science.gov (United States)

Canan, B D; Asti, L; Heaney, C; Ashida, S; Renick, K; Xiang, H; Stallones, L; Jepsen, S D; Crawford, J M; Wilkins, J R

2011-04-01

Unintentional injury is the leading cause of death in the U.S. among persons 1 to 44 years of age. Over one million children and adolescents in the U.S. live, work, and/or play on farms, where injury risk is relatively high compared to other settings. In an attempt to reduce the number of childhood agricultural injuries occurring on farms, the North American Guidelines for Children's Agricultural Tasks (NAGCAT) was developed to assist parents or other caregivers in assigning developmentally appropriate chores to youth exposed to agricultural hazards. The results presented here are from a longitudinal study in which we obtained (self-reported) daily chore, injury, and safety behavior data from children and adolescents. We focused on one NAGCAT chore, cleaning a service alley in a stall barn, in order to estimate the extent of compliance with specific work practice recommendations contained in the NAGCAT. Our results indicated that among the four NAGCAT-recommended safety practices for cleaning service alleys in stall barns (wearing nonskid shoes, leather gloves, a respirator, and eye protection), wearing non-skid shoes was the only safety practice reported with any degree of regularity. Overall, boys were more likely to wear non-skid shoes compared to girls. In addition, older youth were generally more likely to report higher work practice compliance compared to younger youth.

Traumatic funicular phlebitis of the thoracic wall resembling Mondor's disease: a case report

Directory of Open Access Journals (Sweden)

Kondo Takeshi

2011-03-01

Full Text Available Abstract Introduction Mondor's disease is a peculiar form of thrombophlebitis, involving a superficial vein in the subcutaneous fat of the breast or anterior chest wall. Case presentation The author presents a case of a 35-year-old male Japanese patient with cord-like induration in the right lateral thoracic wall. This lesion was diagnosed as traumatic funicular phlebitis, resembling Mondor's disease. Conclusion Traumatic funicular phlebitis, resembling Mondor's disease, is a clinical entity which may give suggestive insight to the etiology of Mondor's disease itself.

ATEFlap aerodynamic model, a dynamic stall model including the effects of trailing edge flap deflection

Energy Technology Data Exchange (ETDEWEB)

Bergami, L.; Gaunaa, M.

2012-02-15

The report presents the ATEFlap aerodynamic model, which computes the unsteady lift, drag and moment on a 2D airfoil section equipped with Adaptive Trailing Edge Flap. The model captures the unsteady response related to the effects of the vorticity shed into the wake, and the dynamics of flow separation a thin-airfoil potential flow model is merged with a dynamic stall model of the Beddoes-Leishmann type. The inputs required by the model are steady data for lift, drag, and moment coefficients as function of angle of attack and flap deflection. Further steady data used by the Beddoes- Leishmann dynamic stall model are computed in an external preprocessor application, which gives the user the possibility to verify, and eventually correct, the steady data passed to the aerodynamic model. The ATEFlap aerodynamic model is integrated in the aeroelastic simulation tool HAWC2, thus al- lowing to simulate the response of a wind turbine with trailing edge flaps on the rotor. The algorithms used by the preprocessor, and by aerodynamic model are presented, and modifications to previous implementations of the aerodynamic model are briefly discussed. The performance and the validity of the model are verified by comparing the dynamic response computed by the ATEFlap with solutions from CFD simulations. (Author)

Effect of paddock vs. stall housing on 24 hour gastric pH within the proximal and ventral equine stomach.

Science.gov (United States)

Husted, L; Sanchez, L C; Olsen, S N; Baptiste, K E; Merritt, A M

2008-06-01

Stall housing has been suggested as a risk factor for ulcer development in the equine stomach; however, the exact pathogenesis for this has not been established. To investigate the effect of 3 environmental situations (grass paddock, stall alone or stall with adjacent companion) on pH in the proximal and the ventral stomach. Six horses with permanently implanted gastric cannulae were used in a randomised, cross-over, block design. Each horse rotated through each of three 24 h environmental situations. Horses remained on their normal diet (grass hay ad libitum and grain b.i.d.) throughout the study. Intragastric pH was measured continuously for 72 h just inside the lower oesophageal sphincter (proximal stomach) and via a pH probe in the gastric cannula (ventral stomach). Neither proximal nor ventral 24 h gastric pH changed significantly between the 3 environmental situations. Mean hourly proximal gastric pH decreased significantly in the interval from 01.00-09.00 h compared to the interval from 13.00-20.00 h, regardless of environmental situation. Median hourly proximal pH only differed in the interval from 06.00-07.00 h compared to the interval 14.00-19.00 h. Neither mean nor median hourly ventral gastric pH varied significantly with the time of day. The change in housing status used in the current study did not affect acid exposure within either region of the equine stomach. The pH in the ventral stomach was uniformly stable throughout the study, while the proximal pH demonstrated a 24 h circadian pattern.

Identification of Thrust, Lift, and Drag for Deep-stall Flight Data of a Fixed-wing Unmanned Aircraft

DEFF Research Database (Denmark)

Cunis, Torbjørn; Leth, Tobias; Totu, Luminita Cristiana

2018-01-01

In this paper, we consider a small unmanned aircraft and data collected during regular and deep-stall flight. We present an identification method for the thrust force generated by the propulsion system based on the in-flight measurements where we make use of the well-known linear and quadratic...... force estimation in the full flight envelope....

RESEMBLANCE OF INDIRECTNESS IN POLITENESS OF EFL LEARNERS’ REQUEST REALIZATIONS

Directory of Open Access Journals (Sweden)

Indawan Syahri

2013-07-01

Full Text Available Abstract: Politeness principles are universally utilized by the speakers of any language when realizing various speech acts. However, the speakers of particular languages relatively apply politeness due to the cultural norms embedded. The present study attempts to delineate how the Indonesian learners of English (ILE apply the politeness principles in request realizations. Specifically it devotes to the types of politeness strategies applied and resemblance of the indirectness in politeness strategies in requesting acts. The FTAs and indirectness are the theoretical bases used to trace the typologies of both politeness and request strategies. The data werere collected by means of certain elicitation techniques, i.e. DCTs and Role-plays. The analyses werere done through three stages; determining request strategies, politeness strategies, and resemblance of indirectness in politeness. The results show that the indirectness generally is parallel to politeness. Besides, some pragmatic transfers are found in terms of applying native-culture norms in realizing target speech acts.

On Learning Natural-Science Categories That Violate the Family-Resemblance Principle.

Science.gov (United States)

Nosofsky, Robert M; Sanders, Craig A; Gerdom, Alex; Douglas, Bruce J; McDaniel, Mark A

2017-01-01

The general view in psychological science is that natural categories obey a coherent, family-resemblance principle. In this investigation, we documented an example of an important exception to this principle: Results of a multidimensional-scaling study of igneous, metamorphic, and sedimentary rocks (Experiment 1) suggested that the structure of these categories is disorganized and dispersed. This finding motivated us to explore what might be the optimal procedures for teaching dispersed categories, a goal that is likely critical to science education in general. Subjects in Experiment 2 learned to classify pictures of rocks into compact or dispersed high-level categories. One group learned the categories through focused high-level training, whereas a second group was required to simultaneously learn classifications at a subtype level. Although high-level training led to enhanced performance when the categories were compact, subtype training was better when the categories were dispersed. We provide an interpretation of the results in terms of an exemplar-memory model of category learning.

Congenital biliary tract malformation resembling biliary cystadenoma in a captive juvenile African lion (Panthera leo).

Science.gov (United States)

Caliendo, Valentina; Bull, Andrew C J; Stidworthy, Mark F

2012-12-01

A captive 3-mo-old white African lion (Panthera leo) presented with clinical signs of acute pain and a distended abdomen. Despite emergency treatment, the lion died a few hours after presentation. Postmortem examination revealed gross changes in the liver, spleen, and lungs and an anomalous cystic structure in the bile duct. Histologic examination identified severe generalized multifocal to coalescent necrotizing and neutrophilic hepatitis, neutrophilic splenitis, and mild interstitial pneumonia, consistent with bacterial septicemia. The abnormal biliary structures resembled biliary cystadenoma. However, due to the age of the animal, they were presumed to be congenital in origin. Biliary tract anomalies and cystadenomas have been reported previously in adult lions, and this case suggests that at least some of these examples may have a congenital basis. It is unclear whether the lesion was an underlying factor in the development of hepatitis.

Spontaneous de novo vaginal adenosis resembling Bartholin’s ...

African Journals Online (AJOL)

Adebayo Alade Adewole

Spontaneous de novo vaginal adenosis resembling Bartholin's cyst: A case report ... 6 by 5 cm. The cervix, uterus, adnexa and Pouch of Douglas (POD) were normal. .... of vaginal cancer.2–4 Although, DES exposed daughters have an.

MRI findings of uterine tumor resembling ovarian sex-cord tumor: A case report

Energy Technology Data Exchange (ETDEWEB)

Cho, Sung Hwan; Kim, Hee Jin; Han, Hyun Young; Hwang, In Taek; Kim, Ju Heon; Lee, Seung Yeon [Eulji University Hospital, Eulji University School of Medicine, Daejeon (Korea, Republic of)

2017-04-15

Uterine tumor resembling ovarian sex-cord tumor is a very rare uterine neoplasm that was first described by Clement and Scully in 1976. Since then, approximately 70 cases have been reported. However, these case reports have mainly described and discussed the pathologic and clinical features, and few radiologic findings have been presented. We experienced a case of a uterine tumor resembling ovarian sex-cord tumor, which was considered a uterine leiomyoma or leiomyosarcoma upon initial impression at preoperative evaluation including transvaginal ultrasonography and pelvic magnetic resonance imaging. Its diagnosis was pathologically confirmed after total abdominal hysterectomy.

Effect of facial self-resemblance on the startle response and subjective ratings of erotic stimuli in heterosexual men.

Science.gov (United States)

Lass-Hennemann, Johanna; Deuter, Christian E; Kuehl, Linn K; Schulz, Andre; Blumenthal, Terry D; Schachinger, Hartmut

2011-10-01

Cues of kinship are predicted to increase prosocial behavior due to the benefits of inclusive fitness, but to decrease approach motivation due to the potential costs of inbreeding. Previous studies have shown that facial resemblance, a putative cue of kinship, increases prosocial behavior. However, the effects of facial resemblance on mating preferences are equivocal, with some studies finding that facial resemblance decreases sexual attractiveness ratings, while other studies show that individuals choose mates partly on the basis of similarity. To further investigate this issue, a psychophysiological measure of affective processing, the startle response, was used in this study, assuming that differences in approach motivation to erotic pictures will modulate startle. Male volunteers (n = 30) viewed 30 pictures of erotic female nudes while startle eyeblink responses were elicited by acoustic noise probes. The female nude pictures were digitally altered so that the face either resembled the male participant or another participant, or were not altered. Non-nude neutral pictures were also included. Importantly, the digital alteration was undetected by the participants. Erotic pictures were rated as being pleasant and clearly reduced startle eyeblink magnitude as compared to neutral pictures. Participants showed greater startle inhibition to self-resembling than to other-resembling or non-manipulated female nude pictures, but subjective pleasure and arousal ratings did not differ among the three erotic picture categories. Our data suggest that visual facial resemblance of opposite-sex nudes increases approach motivation in men, and that this effect was not due to their conscious evaluation of the erotic stimuli.

Stall margin improvements of conventional axial flow fans with the reformed casingtreatments; Casingtreatment ni yoru han`yo jikuryu sofuki no shissoku kaizen

Energy Technology Data Exchange (ETDEWEB)

Nishioka, K.; Kuroda, H.; Obata, S.; Chimura, O. [National Defense Academy, Kanagawa (Japan); Takeishi, M.

1998-09-25

At the first part of this paper, the experiments and results to the blowing and suction on a fan are presented, and it is found that blowing toward the down stream direction are more effective and blowing location is suitable on the leading edge side of blades. On basis of these results, the reformed casingtreatments which the blowing air from the slots makes the large relative momentum for blade chord are build, and the experiments using the two conventional fans equipped with the reformed casingtreatment and conventional one are performed. So, the very large stall margin improvements (about 1.7 times) and about 0.5% efficiency penalty of 10% stall margin improvement at design flow rate are obtained for the reformed casingtreatment. 10 refs., 15 figs., 1 tab.

Resemblances of Parents and Twins in Sport Participation and Heart Rate

NARCIS (Netherlands)

Boomsma, D.I.; van den Bree, M.B.; Orlebeke, J.F.; Molenaar, P.C.M.

1989-01-01

A model to analyze resemblances of twins and parents using LISREL is outlined and applied to sports participation and heart-rate data. Sports participation and heart rate were measured in 44 monozygotic and 46 dizygotic adolescent twin pairs and in their parents. Genetic factors influence variation

FANCJ couples replication past natural fork barriers with maintenance of chromatin structure.

Science.gov (United States)

Schwab, Rebekka A; Nieminuszczy, Jadwiga; Shin-ya, Kazuo; Niedzwiedz, Wojciech

2013-04-01

Defective DNA repair causes Fanconi anemia (FA), a rare childhood cancer-predisposing syndrome. At least 15 genes are known to be mutated in FA; however, their role in DNA repair remains unclear. Here, we show that the FANCJ helicase promotes DNA replication in trans by counteracting fork stalling on replication barriers, such as G4 quadruplex structures. Accordingly, stabilization of G4 quadruplexes in ΔFANCJ cells restricts fork movements, uncouples leading- and lagging-strand synthesis and generates small single-stranded DNA gaps behind the fork. Unexpectedly, we also discovered that FANCJ suppresses heterochromatin spreading by coupling fork movement through replication barriers with maintenance of chromatin structure. We propose that FANCJ plays an essential role in counteracting chromatin compaction associated with unscheduled replication fork stalling and restart, and suppresses tumorigenesis, at least partially, in this replication-specific manner.

Investigating dynamic stall, 3-D and rotational effects on wind turbine blades by means of an unsteady quasi-3D Navier-Stokes solver

Energy Technology Data Exchange (ETDEWEB)

Chaviaropoulos, P.K. [CRES-Center for Renewable Energy Sources, Pikermi Attiki (Greece)

1997-08-01

The blade element codes provide surprisingly accurate predictions of the aerodynamic loads provided that they are `fed` with proper lift and drag - incidence curves for the profiles mounted on the rotor blades. The evident question is how one can obtain such data. It is common experience that the use of the mostly available steady two-dimensional profile data may lead to serious discrepancies between measured and simulated loads. Although several correction techniques have been proposed as a remedy during the last years, from simplified dynamic stall models suitably tuned for wind turbines to 3-D correction schemes for profile data, the problem is by no means over-passed. Especially for the three-dimensional effects it seems that part of the difficulty is due to our limited understanding of the physical mechanism which is responsible for the extra loading of the inner part of the blades. Recognizing the importance of the above aspects two relevant Joule projects have been launched, the concluded `Dynamic Stall and 3-D Effects` JOU2-CT93-0345 and the ongoing `VISCWIND` JOR3-CT95-0007 project. Part of the activities in the first and all the activities in the second project are devoted to the identification and quantification of the dynamic stall and three-dimensional effects experienced by the wind turbine blades using Navier-Stokes computations. The contribution of CRES in these two projects is briefly presented in this paper. (EG)

Family environment, not heredity, accounts for family resemblances in food preferences and attitudes: a twin study.

Science.gov (United States)

Rozin, P; Millman, L

1987-04-01

Monozygotic and same-sex dizygotic twin pairs reported on their food preferences, the variety of foods of the same general category (e.g. types of soup) in their diet, and their concern about contact of their food with disgusting or other unacceptable substances (contamination sensitivity). Although there was substantial resemblance between siblings for many of these items, there was no clear evidence for a heritable component on any item. The only case for which there was an interpretable and significantly greater resemblance among monozygotic than among dizygotic twins (out of 23 questions) was preferred degree of hotness resulting from chili pepper in foods. These results confirm the prediction that in omnivorous animals, such as humans, genetic predispositions will be minimal with respect to food. The modest sibling resemblances on a number of measures are primarily attributable to a shared environment.

A model for roll stall and the inherent stability modes of low aspect ratio wings at low Reynolds numbers

Science.gov (United States)

Shields, Matt

The development of Micro Aerial Vehicles has been hindered by the poor understanding of the aerodynamic loading and stability and control properties of the low Reynolds number regime in which the inherent low aspect ratio (LAR) wings operate. This thesis experimentally evaluates the static and damping aerodynamic stability derivatives to provide a complete aerodynamic model for canonical flat plate wings of aspect ratios near unity at Reynolds numbers under 1 x 105. This permits the complete functionality of the aerodynamic forces and moments to be expressed and the equations of motion to solved, thereby identifying the inherent stability properties of the wing. This provides a basis for characterizing the stability of full vehicles. The influence of the tip vortices during sideslip perturbations is found to induce a loading condition referred to as roll stall, a significant roll moment created by the spanwise induced velocity asymmetry related to the displacement of the vortex cores relative to the wing. Roll stall is manifested by a linearly increasing roll moment with low to moderate angles of attack and a subsequent stall event similar to a lift polar; this behavior is not experienced by conventional (high aspect ratio) wings. The resulting large magnitude of the roll stability derivative, Cl,beta and lack of roll damping, Cl ,rho, create significant modal responses of the lateral state variables; a linear model used to evaluate these modes is shown to accurately reflect the solution obtained by numerically integrating the nonlinear equations. An unstable Dutch roll mode dominates the behavior of the wing for small perturbations from equilibrium, and in the presence of angle of attack oscillations a previously unconsidered coupled mode, referred to as roll resonance, is seen develop and drive the bank angle? away from equilibrium. Roll resonance requires a linear time variant (LTV) model to capture the behavior of the bank angle, which is attributed to the

Injury scores and locomotor disorders of Holstein cows in a free-stall facility with different beds

OpenAIRE

Cecchin, Daiane; Universidade Federal de Lavras - UFLA Lavras - MG; Campos, Alessandro Torres; Universidade Federal de Lavras - UFLA Lavras - MG; Pires, Maria de Fátima Ávila; Sousa, Francine Aparecida; Universidade Federal de Lavras - UFLA Lavras - MG; Amaral, Pedro Ivo Sodré; Universidade Federal de Lavras - UFLA Lavras - MG; Yanagi Junior, Tadayuki; Universidade Federal de Lavras - UFLA Lavras - MG; Ferreira, Suane Alves; Médica Veterinária – UNIPAC Juiz de Fora, MG.; Souza, Myriam Cristiane Morais; Graduanda em Medicina Veterinária – UNIPAC Juiz de Fora, MG.; Cecchin, Diego; Especialista em Gestão – UPF, Passo Fundo, RS

2015-01-01

The aim of the present study was to evaluate hock and knee injuries and locomotor disorders in 36 multiparous Holstein cows confined in a free-stall model system with two types of beds at Embrapa Dairy Cattle in the city of Coronel Pacheco / MG. Rubber composite beds and sand beds were compared and the hock and knee injuries and locomotor disorders were assessed for severity scores. There was no difference between the scores or hock lesions observed at the beginning and end of the trial perio...

Spins, Stalls, and Shutdowns: Pitfalls of Qualitative Policing and Security Research

Directory of Open Access Journals (Sweden)

Randy K. Lippert

2015-11-01

Full Text Available This article explores key elements of qualitative research on policing and security agencies, including barriers encountered and strategies to prevent them. While it is oft-assumed that policing/security agencies are difficult to access due to their clandestine or bureaucratic nature, this article demonstrates this is not necessarily the case, as access was gained for three distinct qualitative research projects. Yet, access and subsequent research were not without pitfalls, which we term security spins, security stalls, and security shutdowns. We illustrate how each was encountered and argue these pitfalls are akin to researchers falling into risk categories, not unlike those used by policing/security agents in their work. Before concluding we discuss methodological strategies for scholars to avoid these pitfalls and to advance research that critically interrogates the immense policing/security realm. URN: http://nbn-resolving.de/urn:nbn:de:0114-fqs1601108

Initial design of a stall-controlled wind turbine rotor

Energy Technology Data Exchange (ETDEWEB)

Nygaard, T.A. [Inst. for Energiteknikk, Kjeller (Norway)

1997-08-01

A model intended for initial design of stall-controlled wind turbine rotors is described. The user specifies relative radial position of an arbitrary number of airfoil sections, referring to a data file containing lift-and drag curves. The data file is on the same format as used in the commercial blade-element code BLADES-/2/, where lift- and drag coefficients are interpolated from tables as function of Reynolds number, relative thickness and angle of attack. The user can set constraints on a selection of the following: Maximum power; Maximum thrust in operation; Maximum root bending moment in operation; Extreme root bending moment, parked rotor; Tip speed; Upper and lower bounds on optimisation variables. The optimisation variables can be selected from: Blade radius; Rotational speed; Chord and twist at an arbitrary number of radial positions. The user can chose linear chord distribution and a hyperbola-like twist distribution to ensure smooth planform and twist, or cubic spline interpolation for one or both. The aerodynamic model is based on classical strip theory with Prandtl tip loss correction, supplemented by empirical data for high induction factors. (EG)

Hock lesions and free-stall design.

Science.gov (United States)

Weary, D M; Taszkun, I

2000-04-01

We compared the prevalence and severity of skin lesions on the hocks of lactating dairy cows in southern British Columbia, comparing 20 farms using three common bedding surfaces: sawdust, sand, and geotextile mattresses. Skin lesions were scored at five positions on the hock. For each position we noted if the lesion showed inflammatory attributes, and then assigned a severity score. Of the 1752 lactating cows scored, 1267 cows (73%) had at least one hock lesion. Of those cows with lesions, 87% had lesions on both legs, 76% had lesions on more than one location on the hock, and 78% had a lesion of at least moderate severity (i.e., evidence of skin breakage or an area of hair loss >10 cm2). Lesions were most prevalent on farms that used geotextile mattresses (91% of cows) and least common on farms that used sand (24% of cows). Moreover, lesions on cows from farms using mattresses were more numerous and more severe than those on cows from sand-bedded farms. The prevalence and severity of lesions on farms using sawdust was intermediate. Lesions also varied in relation to location on the hock. For farms using geotextile mattresses, lesions were more common and more severe on the lateral surfaces of both the tuber calcis and the tarsal joint. On farms using sawdust, lesions were common on the dorsal surface of the tuber calcis and the lateral surfaces of both the tuber calcis and the tarsal joint. Lesions were rare on all five positions for cows from sand-bedded farms. Among the 10 farms sampled using sawdust, we found a significant negative relationship between the length of the stall and severity of lesions. For cows with lesions, the number and severity of lesions increased with age.

Jordan's 2002 to 2012 Fertility Stall and Parallel USAID Investments in Family Planning: Lessons From an Assessment to Guide Future Programming.

Science.gov (United States)

Spindler, Esther; Bitar, Nisreen; Solo, Julie; Menstell, Elizabeth; Shattuck, Dominick

2017-12-28

Health practitioners, researchers, and donors are stumped about Jordan's stalled fertility rate, which has stagnated between 3.7 and 3.5 children per woman from 2002 to 2012, above the national replacement level of 2.1. This stall paralleled United States Agency for International Development (USAID) funding investments in family planning in Jordan, triggering an assessment of USAID family planning programming in Jordan. This article describes the methods, results, and implications of the programmatic assessment. Methods included an extensive desk review of USAID programs in Jordan and 69 interviews with reproductive health stakeholders. We explored reasons for fertility stagnation in Jordan's total fertility rate (TFR) and assessed the effects of USAID programming on family planning outcomes over the same time period. The assessment results suggest that the increased use of less effective methods, in particular withdrawal and condoms, are contributing to Jordan's TFR stall. Jordan's limited method mix, combined with strong sociocultural determinants around reproduction and fertility desires, have contributed to low contraceptive effectiveness in Jordan. Over the same time period, USAID contributions toward increasing family planning access and use, largely focused on service delivery programs, were extensive. Examples of effective initiatives, among others, include task shifting of IUD insertion services to midwives due to a shortage of female physicians. However, key challenges to improved use of family planning services include limited government investments in family planning programs, influential service provider behaviors and biases that limit informed counseling and choice, pervasive strong social norms of family size and fertility, and limited availability of different contraceptive methods. In contexts where sociocultural norms and a limited method mix are the dominant barriers toward improved family planning use, increased national government investments

Unsteady modelling of the oscillating S809 aerofoil and NREL phase VI parked blade using the Beddoes-Leishman dynamic stall model

International Nuclear Information System (INIS)

Gonzalez, Alvaro; Munduate, Xabier

2007-01-01

An implementation of the Beddoes-Leishman dynamic stall model has been developed at CENER, for modelling the unsteady aerodynamics on oscillating blade sections. The parameters of the model were adjusted for the S809 aerofoil, using an optimization based on genetic algorithms, and taking into account the values found in the literature and the physics of the aerodynamic process. Once the parameters were fixed to a unique set, oscillating cases of the 2D S809 aerofoil were computed, and compared with experimental data. Thus, the accuracy of the model was evaluated. On the other hand, oscillating cases of different span stations of the NREL phase VI parked blade were computed and compared with experimental data, to analyze the three-dimensionality of the dynamic stall on the blade sections. For the unsteady computations on the blade, the model was fed with the steady data of the blade section, to directly consider the geometry influence. In general, the results of the computations for the 2D aerofoil and 3D blade sections were very encouraging

G-quadruplexes Significantly Stimulate Pif1 Helicase-catalyzed Duplex DNA Unwinding*

Science.gov (United States)

Duan, Xiao-Lei; Liu, Na-Nv; Yang, Yan-Tao; Li, Hai-Hong; Li, Ming; Dou, Shuo-Xing; Xi, Xu-Guang

2015-01-01

The evolutionarily conserved G-quadruplexes (G4s) are faithfully inherited and serve a variety of cellular functions such as telomere maintenance, gene regulation, DNA replication initiation, and epigenetic regulation. Different from the Watson-Crick base-pairing found in duplex DNA, G4s are formed via Hoogsteen base pairing and are very stable and compact DNA structures. Failure of untangling them in the cell impedes DNA-based transactions and leads to genome instability. Cells have evolved highly specific helicases to resolve G4 structures. We used a recombinant nuclear form of Saccharomyces cerevisiae Pif1 to characterize Pif1-mediated DNA unwinding with a substrate mimicking an ongoing lagging strand synthesis stalled by G4s, which resembles a replication origin and a G4-structured flap in Okazaki fragment maturation. We find that the presence of G4 may greatly stimulate the Pif1 helicase to unwind duplex DNA. Further studies reveal that this stimulation results from G4-enhanced Pif1 dimerization, which is required for duplex DNA unwinding. This finding provides new insights into the properties and functions of G4s. We discuss the observed activation phenomenon in relation to the possible regulatory role of G4s in the rapid rescue of the stalled lagging strand synthesis by helping the replicator recognize and activate the replication origin as well as by quickly removing the G4-structured flap during Okazaki fragment maturation. PMID:25627683

CFD study of a NACA 63-415 aerofoil fitted with stall strips

Energy Technology Data Exchange (ETDEWEB)

Zahle, F.; Soerensen, N.N.; Johansen, J.

2002-09-01

The present work describes a thorough investigation of 2D computations of the flow around a NACA 63-415 aerofoil fitted with stall strips (SS). A mesh study as well as a time step study is carried out and all computations are compared with experiments. Two different SS, 5mm and 7mm are investigated at several positions. Furthermore the influence of laminar to turbulent transition and the effect of a rounded SS were tested. There is not sufficient agreement between the experimental results and the simulations to draw any conclusions of optimum position and geometry of the SS. The 7mm SS's placed at P00 and P-02 has the greatest effect on the max lift followed by SS P02. The 5mm SS's does, as in the experiment, not change the lift curve noticeably. Even though this investigation does not conclusively succeed in verifying the experimental results with CFD, many useful conclusions can be drawn from the results. It is observed in the experiment that the vertical force fluctuates at higher angles of attack. This indicates that small bubbles are being shed off the profile causing the force to vary. This property is observed when transition is included in the model and also when the tip of the SS is rounded. From this result it could be concluded that the level of turbulence produced on the tip of the SS is very important for the development of the flow downstream. In the sharp tip calculations using fully turbulent computations, this is most likely too high, which resulted in the fine structures being damped out, with only one bubble appearing. (au)

Do general radiographic examinations resemble a person-centred environment?

International Nuclear Information System (INIS)

Hayre, C.M.; Blackman, S.; Eyden, A.

2016-01-01

Aim and objective: It is argued whether general radiographic examinations adhere to a person-centred approach within the direct digital radiography (DDR) environment. General radiographic examinations continue to increase and constitute approximately 90% of all examinations undertaken in the clinical environment. This study explored the potential impact patients experience whilst undergoing general imaging examinations. Method: An ethnographic methodology provided insight of two general radiography environments in the United Kingdom (UK) using participant observation and semi-structured interviews. Findings: The findings highlighted an ‘in and out’ culture whereby patients are ‘hurried’ and ‘rushed’ out of X-ray rooms in response to increasing time pressures experienced by diagnostic radiographers. In addition, this study challenged that patients may begin to rank ‘speed’ and ‘waiting times’ above other elements of radiographic care thus presenting new challenges for radiographers within the clinical environment. Conclusion: It is asserted that radiographers should remain holistic healthcare professionals and not begin to resemble operators on the production line. Further, it challenges whether patients are beginning to rank aspects of radiographic care within contemporary practices. Advances in knowledge: Few studies have explored the radiographer–patient relationship within the DDR environment, yet this study provides insight of person-centred practices within contemporary practices. - Highlights: • Challenges whether the use of DDR conforms to a person-centred approach. • Challenges whether radiographers are ‘treating patients as persons’ using DDR. • Patients may begin to rank ‘speed’ and ‘waiting times’ above other aspects of radiographic care.

Autosomal dominant syndrome resembling Coffin-Siris syndrome.

Science.gov (United States)

Flynn, Maureen A; Milunsky, Jeff M

2006-06-15

Coffin-Siris syndrome is a multiple congenital anomaly/mental retardation syndrome with phenotypic variability [OMIM 135900]. The diagnosis is based solely on clinical findings, as there is currently no molecular, biochemical, or cytogenetic analysis available to confirm a diagnosis. Although typically described as an autosomal recessive disorder, autosomal dominant inheritance has also been infrequently reported. We describe a mother and her two daughters who all have features that resemble Coffin-Siris syndrome. However, this is not a completely convincing diagnosis given that hypertelorism is not a feature of Coffin-Siris syndrome and the family is relatively mildly affected. Yet, this family provides further evidence of an autosomal dominant mode of inheritance for a likely variant of Coffin-Siris syndrome (at least in some families). In addition, Sibling 1 had premature thelarche. She is the second reported individual within the spectrum of Coffin-Siris syndrome to have premature thelarche, indicating that it may be a rare clinical feature. Copyright 2006 Wiley-Liss, Inc.

Covalent structures of potato tuber lipases (patatins) and implications for vacuolar import

DEFF Research Database (Denmark)

Welinder, Karen Gjesing; Jørgensen, Malene

2009-01-01

patatin (Rydel, T. J., Williams, J. M., Krieger, E., Moshiri, F., Stallings, W. C., Brown, S. M., Pershing, J. C., Prucell, J. P., and Alibhai, M. F. (2003) Biochemistry 42, 6696-6708), which included this propeptide thus, for the first time, shows the structure of a putative ligand of the vacuolar...

Performance augmentation with vortex generators: Design and testing for stall-regulated AWT-26 turbine

Energy Technology Data Exchange (ETDEWEB)

Griffin, D.A. [Advanced Wind Turbines Inc., Seattle, WA (United States)

1996-12-31

A study investigated the use of vortex generators (VGs) for performance augmentation of the stall-regulated AWT-26 wind turbine. Based on wind-tunnel results and analysis, a VG array was designed for and tested on the AWT-26 prototype, designated Pt. Performance and loads data were measured for P1, both with and without VGs installed. The turbine performance with VGs met most of the design requirements; power output was increased at moderate wind speeds with a minimal effect on peak power. However, VG drag penalties caused a loss in power output for low wind speeds, such that performance with VGs resulted in a net decrease in AEP for wind speed sites up to 8.5 m/s. 8 refs., 8 figs., 3 tabs.

Stalling HIV through social marketing: prospects in Pakistan.

Science.gov (United States)

Husain, Sara; Shaikh, Babar T

2005-07-01

Over the last two decades HIV/AIDS has evolved from a series of interesting case-reports to a growing epidemic that threatens the entire world. It is feared to cause devastation among large pockets of populations and may roll back more than thirty years of public health achievements. This killer disease has been more amenable to behavioral change than by provision of curative services and attempts are being made to educate the public about this threat. Various techniques of promotion have been tried through out the world including television dramas/soaps, mass media and school curricula. Social marketing is an evolving strategy used to influence human behavior and choices. By using the principles of marketing and promoting behavior as a product, social marketers attempt to understand the dynamics of human behaviour and devise messages and products to change, modify, accept or reject unsafe behaviors or practices. Thus, social marketers provide an effective force to combat the spread of HIV and may serve to be invaluable allies in health promotion efforts. In a complex and diversified cultural milieu of Pakistan, social marketing can have a significant impact on health determinants and the conditions that will facilitate the adoption of health-oriented behaviors and practices. This paper gives an account of the elements needed for the success of a health promotion strategy adopted in a developing country and makes a case for social marketing to be adopted as the lead strategy for stalling HIV/AIDS in Pakistan.

Children and Adolescents' Understandings of Family Resemblance: A Study of Naive Inheritance Concepts

Science.gov (United States)

Williams, Joanne M.

2012-01-01

This paper aims to provide developmental data on two connected naive inheritance concepts and to explore the coherence of children's naive biology knowledge. Two tasks examined children and adolescents' (4, 7, 10, and 14 years) conceptions of phenotypic resemblance across kin (in physical characteristics, disabilities, and personality traits). The…

The efforts of a multidisciplinary approach in the rehabilitation institute for deaf children: A psychosocial intervention aimed at breaking the pattern of stalled productivity

Directory of Open Access Journals (Sweden)

Langher Viviana

2012-01-01

Full Text Available The multidisciplinary approach for the treatment of hearing impaired children presented the work group with several tasks: the group had to integrate different competences and techniques, to share common treatment goals, to manage relational dynamics with the children and their parents, and to explore the families' expectancies. These efforts may create stressful conditions for the work group and, consequently, might negatively affect the quality of the intervention to be carried out. Our aim was to illustrate a psychosocial analysis performed in a religious Institute for hearing impaired children, intended to break the pattern of the Institute's stalled productivity, to avoid inefficient and fragmented treatments, to prevent unelaborated relational dynamics among the staff members and between the staff and the children's families. By means of the Content Analysis of semi-structured interviews administered to staff-members and families we have analyzed the quality of the teamwork, the relational arrangements towards the families and local services (25 interviews with 5 staff members; the family-Institute relationship and the family's representation and satisfaction of the Institute (7 interviews with 13 hearing impaired parents and non-hearing impaired parents. The institute activity seemed to be more characterized by the maintenance of the relationship with the families per se, rather than oriented to productive goals. The non hearing impaired parents seemed to be more satisfied than the hearing-impaired parents, possibly because the former are more prepared to receive the Institute's help. The stalled productivity can only be overcome by the elaboration of those relational/emotional dynamics which prevent staff members and children's parents from focusing on productive goals. The staffmembers' training should be improved in order to develop specific competences, to perform an integrated, multidisciplinary approach in treatments, to negotiate

Reducing Respiratory Health Risks to Horses and Workers: A Comparison of Two Stall Bedding Materials

Directory of Open Access Journals (Sweden)

Markku Saastamoinen

2015-10-01

Full Text Available Stable air quality and the choice of bedding material are an important health issue both in horses and people working or visiting horse stables. Risks of impaired respiratory health are those that can especially be avoided by improving air quality in the stable. The choice of bedding material is particularly important in cold climate conditions; where horses are kept most of the day and year indoors throughout their life. This study examined the effect of two bedding materials; wood shavings and peat; on stable air quality and health of horses. Ammonia and dust levels were also measured to assess conditions in the stable. Ammonia was not detected or was at very low levels (<0.25 ppm in the boxes in which peat was used as bedding; but its concentration was clearly higher (1.5–7.0 ppm in stalls with wood shavings as bedding. Personal measurements of workers revealed quite high ammonia exposure (5.9 ppm8h in the boxes in which wood shavings were used; but no exposure was Animals 2015, 5 966 observed in stalls bedded with peat. The respiratory symptoms in horses increased regardless of the bedding material at the beginning of the study. The health status of the horses in the peat bedding group returned to the initial level in the end of the trial but horses bedded with wood shavings continued to be symptomatic. The hooves of the horses with peat bedding had a better moisture content than those of the horses bedded with wood shavings. The results suggest that peat is a better bedding material for horses than wood shavings regarding the health of both horses and stable workers.

Coordinating repair of oxidative DNA damage with transcription and replication

International Nuclear Information System (INIS)

Cooper, P.K.

2003-01-01

Transcription-coupled repair (TCR) preferentially removes DNA lesions from template strands of active genes. Defects in TCR, which acts both on lesions removed by nucleotide excision repair (NER) and on oxidative lesions removed by base excision repair (BER), underlie the fatal developmental disorder Cockayne syndrome. Although its detailed mechanism remains unknown, TCR involves recognition of a stalled RNA polymerase (RNAP), removal or remodeling of RNAP to allow access to the lesion, and recruitment of repair enzymes. At a minimum, these early steps require a non-enzymatic function of the multifunctional repair protein XPG, the CSB protein with ATP-dependent chromatin remodeling activity, and the TFIIH complex (including the XPB and XPD helicases) that is also required for basal transcription initiation and NER. XPG exists in the cell in a complex with TFIIH, and in vitro evidence has suggested that it interacts with CSB. To address the mechanism of TCR, we are characterizing protein-DNA and protein-protein interactions of XPG. We show that XPG preferentially binds to double-stranded DNA containing bubbles resembling in size the unpaired regions associated with transcription. Two distinct domains of XPG are required for the observed strong binding specificity and stability. XPG both interacts directly with CSB and synergistically binds with it to bubble DNA, and it strongly stimulates the bubble DNA-dependent ATPase activity of CSB. Significantly for TCR, XPG also interacts directly with RNAP II, binds both the protein and nucleic acid components (the R-loop) of a stalled RNA polymerase, and forms a ternary complex with CSB and the stalled RNAP. These results are consistent with the model that XPG and CSB jointly interact with the DNA/chromatin structure in the vicinity of the stalled transcriptional apparatus and with the transcriptional machinery itself to remodel the chromatin and either move or remodel the blocked RNA polymerase to expose the lesion

Effects of parenting quality on adolescents' personality resemblance to their parents. The TRAILS study

NARCIS (Netherlands)

Langenhof, M Rohaa; Komdeur, Jan; Oldehinkel, Albertine J.

This study considers the development of resemblance between 741 adolescents and their biological parents, across six NEO-PI-R personality traits known to be important in psychological problems: anger-hostility, impulsiveness, vulnerability, assertiveness, excitement-seeking, and self-discipline. We

Familial resemblance of borderline personality disorder features: genetic or cultural transmission?

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Marijn A Distel

Full Text Available Borderline personality disorder is a severe personality disorder for which genetic research has been limited to family studies and classical twin studies. These studies indicate that genetic effects explain 35 to 45% of the variance in borderline personality disorder and borderline personality features. However, effects of non-additive (dominance genetic factors, non-random mating and cultural transmission have generally not been explored. In the present study an extended twin-family design was applied to self-report data of twins (N = 5,017 and their siblings (N = 1,266, parents (N = 3,064 and spouses (N = 939 from 4,015 families, to estimate the effects of additive and non-additive genetic and environmental factors, cultural transmission and non-random mating on individual differences in borderline personality features. Results showed that resemblance among biological relatives could completely be attributed to genetic effects. Variation in borderline personality features was explained by additive genetic (21%; 95% CI 17-26% and dominant genetic (24%; 95% CI 17-31% factors. Environmental influences (55%; 95% CI 51-60% explained the remaining variance. Significant resemblance between spouses was observed, which was best explained by phenotypic assortative mating, but it had only a small effect on the genetic variance (1% of the total variance. There was no effect of cultural transmission from parents to offspring.

Is Social Licence A Licence To Stall?

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Mark Lowey

2016-03-01

Full Text Available The School of Public Policy at the University of Calgary organized a one-day symposium on Oct. 8, 2014 in Calgary, as part of the School’s TransCanada Corporation Energy Policy and Regulatory Frameworks Program. The symposium was titled “Is Social License a License to Stall?” Held at the Hotel Arts, the event attracted a full-capacity audience of about 110 people, including representatives from industry, government and environmental non-government organizations. The symposium included four moderated panel sessions and a keynote speaker at lunch. The School of Public Policy set the framework for discussion at the Calgary symposium with the following description: Canada’s regulators act in the public interest to review energy and infrastructure project applications. Regulators are guided by procedural fairness and follow a transparent application, review and hearing process with data filings and sworn testimony. But that’s changing. “Social license” is a relatively new term, which some interests are using to create a different standard for the approval of projects — especially energy projects. According to social license advocates, projects must meet often ill-defined requirements set up by non-governmental organizations, local residents or other interests — a new hurdle for project approval, but without the rigour and rule of law of a regulator. Is social license a meaningful addition to the regulatory process, or is it being used as a constantly moving goal-post designed to slow down regulatory processes, delay project implementation, frustrate energy infrastructure expansion and even enrich those advocates who promote it as a new model? This paper summarises the discussion and the themes that emerged throughout the day. Most notably, panellists concluded that “social licence” is a real and significant issue that presents both an opportunity and a problem, not only for regulators but for all parties involved in the

Household and familial resemblance in risk factors for type 2 diabetes and related cardiometabolic diseases in rural Uganda

DEFF Research Database (Denmark)

Nielsen, Jannie; Bahendeka, Silver K.; Whyte, Susan R.

2017-01-01

prevention and screening, we investigated the resemblance of T2D risk factors at household level and by type of familial dyadic relationship in a rural Ugandan community. Methods: This cross-sectional household-based study included 437 individuals ≥13 years of age from 90 rural households in south......-western Uganda. Resemblance in glycosylated haemoglobin (HbA1c), anthropometry, blood pressure, fitness status and sitting time were analysed using a general mixed model with random effects (by household or dyad) to calculate household intraclass correlation coefficients (ICCs) and dyadic regression coefficients...... (ICC=0.24), HbA1c (ICC=0.18) and systolic blood pressure (ICC=0.11). Regarding dyadic resemblance, the highest standardised regression coefficient was seen in fitness status for spouses (0.54, 95% CI 0.32 to 0.76), parent–offspring (0.41, 95% CI 0.28 0.54) and siblings (0.41, 95% CI 0.25 to 0...

From FRA to RFN, or How the Family Resemblance Approach Can Be Transformed for Science Curriculum Analysis on Nature of Science

Science.gov (United States)

Kaya, Ebru; Erduran, Sibel

2016-01-01

The inclusion of Nature of Science (NOS) in the science curriculum has been advocated around the world for several decades. One way of defining NOS is related to the family resemblance approach (FRA). The family resemblance idea was originally described by Wittgenstein. Subsequently, philosophers and educators have applied Wittgenstein's idea to…

Toric Codes, Multiplicative Structure and Decoding

DEFF Research Database (Denmark)

Hansen, Johan Peder

2017-01-01

Long linear codes constructed from toric varieties over finite fields, their multiplicative structure and decoding. The main theme is the inherent multiplicative structure on toric codes. The multiplicative structure allows for \\emph{decoding}, resembling the decoding of Reed-Solomon codes and al...

A ruthenium polypyridyl intercalator stalls DNA replication forks, radiosensitizes human cancer cells and is enhanced by Chk1 inhibition

Science.gov (United States)

Gill, Martin R.; Harun, Siti Norain; Halder, Swagata; Boghozian, Ramon A.; Ramadan, Kristijan; Ahmad, Haslina; Vallis, Katherine A.

2016-08-01

Ruthenium(II) polypyridyl complexes can intercalate DNA with high affinity and prevent cell proliferation; however, the direct impact of ruthenium-based intercalation on cellular DNA replication remains unknown. Here we show the multi-intercalator [Ru(dppz)2(PIP)]2+ (dppz = dipyridophenazine, PIP = 2-(phenyl)imidazo[4,5-f][1,10]phenanthroline) immediately stalls replication fork progression in HeLa human cervical cancer cells. In response to this replication blockade, the DNA damage response (DDR) cell signalling network is activated, with checkpoint kinase 1 (Chk1) activation indicating prolonged replication-associated DNA damage, and cell proliferation is inhibited by G1-S cell-cycle arrest. Co-incubation with a Chk1 inhibitor achieves synergistic apoptosis in cancer cells, with a significant increase in phospho(Ser139) histone H2AX (γ-H2AX) levels and foci indicating increased conversion of stalled replication forks to double-strand breaks (DSBs). Normal human epithelial cells remain unaffected by this concurrent treatment. Furthermore, pre-treatment of HeLa cells with [Ru(dppz)2(PIP)]2+ before external beam ionising radiation results in a supra-additive decrease in cell survival accompanied by increased γ-H2AX expression, indicating the compound functions as a radiosensitizer. Together, these results indicate ruthenium-based intercalation can block replication fork progression and demonstrate how these DNA-binding agents may be combined with DDR inhibitors or ionising radiation to achieve more efficient cancer cell killing.

Perceptions of the organization's climate: influenced by the organization's structure?

Science.gov (United States)

Grigsby, K A

1991-02-01

Currently, little is known about organizational climates in schools of nursing, and what structural factors are associated with climate variations. The purpose of this study is to describe the organizational structure and climate, and the interrelationship between these factors, in two schools of nursing. Results indicated that the sample organizations exhibited characteristics of both the bureaucratic and professional models of organizational structure, although one school was more closely aligned to the professional model. Organizational climates differed in the two schools, and the school that structurally resembled the professional model had a more facilitative climate. Organizational structure was significantly (p less than .01) related to the climate dimensions of autonomy (r = -.35), work pressure (r = .49), and control (r = .59). The schools differed significantly (p less than .01) on the climate dimensions of administrative support (t = 3.31, df = 54), autonomy (t = 3.30, df = 56), work pressure (t = -4.36, df = 60), and control (t = -6.74, df = 55). Administrative support and autonomy were higher in the school structurally resembling the professional model, and work pressure and control were higher in the school structurally resembling the bureaucratic model.

Welfare assessment of dairy cows housed in a tie-stall system

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Marija Vučemilo

2012-03-01

Full Text Available Welfare assessment methods and techniques developed as a result of great interest of scientific and consumer populations regarding the welfare of animals housed in farms. In view of the fact that welfare by definition includes both physical and mental health, the welfare quality assessment includes an extensive number of measures. Welfare assessment was performed in two stables in which cows are kept in tie-stall by using the specific method described in the Welfare Quality® Assessment Protocol for Cattle. The measures included body condition score, qualitative behaviour assessment and body hygiene. The welfare assessment confirmed the importance of quality housing for ensuring better performance from animals, thus also affecting their health and productivity. It also pointed out the necessity of freeing animals by providing them with the possibility of free movement, whereat they can exhibit their physiological behaviour. It is definitely important to continue research, expand the number of researched measures in order to confirm the most useful indicators for welfare assessment and to identify the factors that within the animals’ physical and social environment affect the increase of their welfare.

Descriptive Understandings of the Nature of Science: Examining the Consensual and Family Resemblance Approaches

Science.gov (United States)

do Nascimento Rocha, Maristela; Gurgel, Ivã

2017-01-01

This paper performs a critical analysis of the consensual and family resemblance approaches to the nature of science. Despite the debate that surrounds them, between a pragmatic consensus and a more comprehensive understanding, both approaches have in common the goal of helping students to "internalize" knowledge about science in a…

Visual Timing of Structured Dance Movements Resembles Auditory Rhythm Perception

Science.gov (United States)

Su, Yi-Huang; Salazar-López, Elvira

2016-01-01

Temporal mechanisms for processing auditory musical rhythms are well established, in which a perceived beat is beneficial for timing purposes. It is yet unknown whether such beat-based timing would also underlie visual perception of temporally structured, ecological stimuli connected to music: dance. In this study, we investigated whether observers extracted a visual beat when watching dance movements to assist visual timing of these movements. Participants watched silent videos of dance sequences and reproduced the movement duration by mental recall. We found better visual timing for limb movements with regular patterns in the trajectories than without, similar to the beat advantage for auditory rhythms. When movements involved both the arms and the legs, the benefit of a visual beat relied only on the latter. The beat-based advantage persisted despite auditory interferences that were temporally incongruent with the visual beat, arguing for the visual nature of these mechanisms. Our results suggest that visual timing principles for dance parallel their auditory counterparts for music, which may be based on common sensorimotor coupling. These processes likely yield multimodal rhythm representations in the scenario of music and dance. PMID:27313900

Numerical study of the static and pitching RISOe-B1-18 airfoil[STALL

Energy Technology Data Exchange (ETDEWEB)

Bertagnolio, F.

2004-01-01

The objective of this report is the better understanding of the physics of the aeroelastic motion of wind turbine blades in order to improve the numerical models used for their design. In this study, the case of the RISOe-B1-18 airfoil which was equipped and measured in an open jet wind tunnel is studied. Two and three dimensional Navier-Stokes calculations using the k-w SST and Detached Eddy Simulation turbulence models are conducted. An engineering semi-empirical dynamic stall model is also used for performing calculations. Computational results are compared to the experimental results that are available both for the static airfoil and in the case of pitching motions. It is shown that the Navier-Stokes simulations can reproduced the main characteristic features of the flow. The DES model seems also to be able to reproduce some details of the unsteady aerodynamics. The Navier-Stokes computations can then be used to improve the performance of the engineering model. (au)

Resembling a viper: implications of mimicry for conservation of the endangered smooth snake.

Science.gov (United States)

Valkonen, Janne K; Mappes, Johanna

2014-12-01

The phenomenon of Batesian mimicry, where a palatable animal gains protection against predation by resembling an unpalatable model, has been a core interest of evolutionary biologists for 150 years. An extensive range of studies has focused on revealing mechanistic aspects of mimicry (shared education and generalization of predators) and the evolutionary dynamics of mimicry systems (co-operation vs. conflict) and revealed that protective mimicry is widespread and is important for individual fitness. However, according to our knowledge, there are no case studies where mimicry theories have been applied to conservation of mimetic species. Theoretically, mimicry affects, for example, frequency dependency of predator avoidance learning and human induced mortality. We examined the case of the protected, endangered, nonvenomous smooth snake (Coronella austriaca) that mimics the nonprotected venomous adder (Vipera berus), both of which occur in the Åland archipelago, Finland. To quantify the added predation risk on smooth snakes caused by the rarity of vipers, we calculated risk estimates from experimental data. Resemblance of vipers enhances survival of smooth snakes against bird predation because many predators avoid touching venomous vipers. Mimetic resemblance is however disadvantageous against human predators, who kill venomous vipers and accidentally kill endangered, protected smooth snakes. We found that the effective population size of the adders in Åland is very low relative to its smooth snake mimic (28.93 and 41.35, respectively).Because Batesian mimicry is advantageous for the mimic only if model species exist in sufficiently high numbers, it is likely that the conservation program for smooth snakes will fail if adders continue to be destroyed. Understanding the population consequences of mimetic species may be crucial to the success of endangered species conservation. We suggest that when a Batesian mimic requires protection, conservation planners should

A wolf in sheep's clothing: The description of a fly resembling jumping spider of the genus Scoturius Simon, 1901 (Araneae: Salticidae: Huriini).

Science.gov (United States)

Perger, Robert; Rubio, Gonzalo D

2018-01-01

Fly resemblance in arthropods is much less common than e.g., resemblance to ants or wasps, and has been mainly observed in beetles. Putative fly mimicry in arachnids has been reported only from the jumping spider genus Saitis. However, recent literature has attributed the fly-resembling characteristics in Saitis to sexual signalling during courtship. The lack of observation of fly mimicry in spiders is not surprising as flies belong to the most important prey item group of spiders. In this study, a new fly-resembling species of the jumping spider tribe Huriini, Scoturius dipterioides sp. nov., from the pre-Andean Chiquitano forest at the Bolivian orocline is described and illustrated. The new species was tentatively placed into Scoturius because the epigynum has a single large elliptical opening. Scoturius dipterioides sp. nov. is distinguished from all other species of this tribe by a combination of following characteristics: epigynum with a large anterior elliptical atrium and initial portion of the copulation ducts dilated as a chamber (shared with Urupuyu); relatively joined copulation openings and short copulation ducts; kidney-shaped spermathecae, advanced at the atrium level. Several somatic features, two of them found exclusively in S. dipterioides sp. nov., increase the resemblance to flies. The Huriini are currently the only spider tribe that is suggested to feature fly mimics.

Neutrophilic dermatosis resembling pyoderma gangrenosum in a dog with polyarthritis.

Science.gov (United States)

Bardagí, M; Lloret, A; Fondati, A; Ferrer, L

2007-04-01

This report describes a case of neutrophilic dermatosis in a dog, with a number of clinical and pathological similarities to human pyoderma gangrenosum. A seven-year-old, female German shepherd dog with a history of non-erosive idiopathic polyarthritis was presented with severe facial swelling, bilateral erosivoulcerative lesions on the muzzle and multiple, eroded, dermal-subcutaneous nodules on the cranial trunk. Histopathological examination of skin biopsies revealed a necrotising neutrophilic dermatitis. No infectious agents could be detected using specific stains, immunohistochemistry, serology and bacterial aerobic, anaerobic or fungal cultures. A sterile neutrophilic dermatosis resembling human pyoderma gangrenosum was presumptively diagnosed, and the patient showed an excellent response to treatment with prednisone and ciclosporin.

Perdas econômicas ocasionadas pelas enfermidades podais em vacas leiteiras confinadas em sistema free stall Economic losses caused by sequels of lameness in free-stall-housed dairy cows

Directory of Open Access Journals (Sweden)

R.C. Souza

2006-12-01

Full Text Available Avaliaram-se 55 casos clínicos de manqueira em um rebanho de 100 vacas em lactação confinadas em sistema de free stall, durante um ano. As afecções mais observadas foram abscessos de sola e talão, úlcera de sola e dermatite digital que representaram 87,3% (48/55 das ocorrências. O tratamento empregado mostrou-se satisfatório com recuperação de todos os animais tratados com 24,5 dias, em média, sem ocorrência de descarte. O custo com tratamento e redução na produção de leite foi de US$95.80/vaca, o que representou US$52.69 por vaca alojada/ano. Quando se computaram as perdas reprodutivas e com mastite, obtiveram-se US$227.94 adicionais em vaca com problema de manqueira. O custo adicional anual total no rebanho decorrente de seqüelas de manqueira foi de US$12,536.70, que representou US$125.36 por vaca alojada/ano. O período de serviço e o número de serviços por concepção em vacas com problemas de manqueira e normais foram 266 e 200,5 dias e 4,3 e 3,3 serviços, respectivamente. As incidências de mastite e metrite na mesma ordem de citação anterior foram 60% e 25% e 29% e 12,5%.Fifty-five clinical cases of lameness were evaluated in 100 lactating cows housed in a free-stall system during one year. The most observed affections were sole and heel abscesses, sole ulcers and digital dermatitis that accounted for 87.3% (48/55 of the occurrences. The treated cows showed satisfactory recovery (24.5 average days without culling. The total individual cost including treatment and reduction of milk production was US$95.80/cow or US$52.69 per housed cow/year. When reproductive losses and mastitis were considered an additional cost of US$227.94 per lameness cow was estimated. The total additional annual cost from sequels of lameness was US$12.536.70 or US$152.36 per housed cow/year. The number of days open and the number of services per conception in lameness and normal cows were, respectively, 266 and 200.5 days and 4.3 and 3

A Para-Canalicular Abscess Resembling an Inflamed Chalazion

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Diamantis Almaliotis

2013-01-01

Full Text Available Background. Lacrimal infections by Actinomyces are rare and commonly misdiagnosed for long periods of time. They account for 2% of all lacrimal diseases. Case Report. We report a case of a 70-year-old female patient suffering from a para-canalicular abscess in the medial canthus of the left eye, beside the lower punctum lacrimale, resembling a chalazion. Purulence exited from the punctum lacrimale due to inflammation of the inferior canaliculus (canaliculitis. When pressure was applied to the mass, a second exit of purulence was also observed under the palpebral conjunctiva below the lacrimal caruncle. A surgical excision was performed followed by administration of local antibiotic therapy. The histopathological examination of the extracted mass revealed the existence of actinomycosis. Conclusion. Persistent or recurrent infections and lumps of the eyelids should be thoroughly investigated. Actinomyces as a causative agent should be considered. Differential diagnosis is broad and should include canaliculitis, chalazion, and multiple types of neoplasias. For this reason, in nonconclusive cases, a histopathological examination should be performed.

Muscular dystrophy in a dog resembling human becker muscular dystrophy.

Science.gov (United States)

Baroncelli, A B; Abellonio, F; Pagano, T B; Esposito, I; Peirone, B; Papparella, S; Paciello, O

2014-05-01

A 3-year-old, male Labrador retriever dog was presented with clinical signs of progressive exercise intolerance, bilateral elbow extension, rigidity of the forelimbs, hindlimb flexion and kyphosis. Microscopical examination of muscle tissue showed marked variability in myofibre size, replacement of muscle with mature adipose tissue and degeneration/regeneration of muscle fibres, consistent with muscular dystrophy. Immunohistochemical examination for dystrophin showed markedly reduced labelling with monoclonal antibodies specific for the rod domain and the carboxy-terminal of dystrophin, while expression of β-sarcoglycan, γ-sarcoglycan and β-dystroglycan was normal. Immunoblotting revealed a truncated dystrophin protein of approximately 135 kDa. These findings supported a diagnosis of congenital canine muscular dystrophy resembling Becker muscular dystrophy in man. Copyright © 2014 Elsevier Ltd. All rights reserved.

Menstrual blood closely resembles the uterine immune micro-environment and is clearly distinct from peripheral blood

NARCIS (Netherlands)

Molen, R.G. van der; Schutten, J.H.; Cranenbroek, B. van; Meer, M. ter; Donckers, J.; Scholten, R.R.; Heijden, O.W.H. van der; Spaanderman, M.E.A.; Joosten, I.

2014-01-01

STUDY QUESTION: Is menstrual blood a suitable source of endometrial derived lymphocytes? SUMMARY ANSWER: Mononuclear cells isolated from menstrual samples (menstrual blood mononuclear cells (MMC)) are clearly distinct from peripheral blood mononuclear cells (PBMC) and show a strong resemblance with

Image and Global Resemblance in the Light of Hadith “Who So Imitates other People Becomes One of Them”

Directory of Open Access Journals (Sweden)

SERDAR DEMİREL

2016-06-01

Full Text Available In today’s world, people from different countries, cities and institutions unprecedentedly resemble each other in every aspect of life. Likewise, the deeds and imagery aspirations of Oriental and Occidental people also resemble. In such an atmosphere, the local cultures rooted in history become accessories and lose their historical significance and metaphysical aspects in the edifice of the society. This study aims to analyze Prophet Muhammad’s (s.a.w. warning, “Who so imitates other people becomes one of them”, its layers of meaning and its relationship with “image and global resemblence”.

Consolation in the aftermath of robberies resembles post-aggression consolation in chimpanzees

DEFF Research Database (Denmark)

Lindegaard, Marie Rosenkrantz; Liebst, Lasse Suonperä; Bernasco, Wim

2017-01-01

Post-aggression consolation is assumed to occur in humans as well as in chimpanzees. While consolation following peer aggression has been observed in children, systematic evidence of consolation in human adults is rare. We used surveillance camera footage of the immediate aftermath of nonfatal...... to be consoled. Furthermore, we show that high levels of threat during the robbery increased the likelihood of receiving consolation afterwards. These patterns resemble post-aggression consolation in chimpanzees and suggest that emotions of empathic concern are involved in consolation across humans...... and chimpanzees....

Mammographic texture resemblance generalizes as an independent risk factor for breast cancer

DEFF Research Database (Denmark)

Nielsen, Mads; Vachon, Celine M.; Scott, Christopher G.

2014-01-01

INTRODUCTION:Breast density has been established as a major risk factor for breast cancer. We have previously demonstrated that mammographic texture resemblance (MTR), recognizing the local texture patterns of the mammogram, is also a risk factor for breast cancer, independent of percent breast...... density. We examine if these findings generalize to another population.METHODS:Texture patterns were recorded in digitalized pre-diagnosis (3.7years) film mammograms of a nested case-control study within the Dutch screening program (S1) comprising of 245 breast cancers and 250 matched controls...

Dermatitis and lymphadenitis resembling juvenile cellulitis in a four-year-old dog.

Science.gov (United States)

Neuber, A E; van den Broek, A H M; Brownstein, D; Thoday, K L; Hill, P B

2004-05-01

A four-year-old, entire male toy poodle was presented with a two-and-a-half-week history of ocular discharge progressing to periorbital alopecia, depigmentation, alopecia and ulceration around the muzzle. There was also a haemorrhagic discharge from the ears, pyrexia, lethargy and generalised lymphadenopathy. The clinical, cytological, bacteriological and histopathological findings were consistent with a diagnosis of dermatitis resembling juvenile cellulitis in an adult dog. Glucocorticoid therapy led to rapid resolution of the clinical signs and the dog has remained in remission for two years after cessation of treatment.

Body elimination attitude family resemblance in Kuwait.

Science.gov (United States)

Al-Fayez, Ghenaim; Awadalla, Abdelwahid; Arikawa, Hiroko; Templer, Donald I; Hutton, Shane

2009-12-01

The purpose of the present study was to determine the family resemblance of attitude toward body elimination in Kuwaiti participants. This study was conceptualized in the context of the theories of moral development, importance of cleanliness in the Muslim religion, cross-cultural differences in personal hygiene practices, previous research reporting an association between family attitudes and body elimination attitude, and health implications. The 24-item Likert-type format Body Elimination Attitude Scale-Revised was administered to 277 Kuwaiti high school students and 437 of their parents. Females scored higher, indicating greater disgust, than the males. Moreover, sons' body elimination attitude correlated more strongly with fathers' attitude (r = .85) than with that of the mothers (r = .64). Daughters' attitude was similarly associated with the fathers' (r = .89) and the mothers' attitude (r = .86). The high correlations were discussed within the context of Kuwait having a collectivistic culture with authoritarian parenting style. The higher adolescent correlations, and in particular the boys' correlation with fathers than with mothers, was explained in terms of the more dominant role of the Muslim father in the family. Public health and future research implications were suggested. A theoretical formulation was advanced in which "ideal" body elimination attitude is relative rather than absolute, and is a function of one's life circumstances, one's occupation, one's culture and subculture, and the society that one lives in.

Insight into Rotational Effects on a Wind Turbine Blade Using Navier–Stokes Computations

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Iván Herráez

2014-10-01

Full Text Available Rotational effects are known to influence severely the aerodynamic performance of the inboard region of rotor blades. The underlying physical mechanisms are however far from being well understood. The present work addresses this problem using Reynolds averaged Navier–Stokes computations and experimental results of the MEXICO (Model Experiments in Controlled Conditions rotor. Four axisymmetric inflow cases with wind speeds ranging from pre-stall to post-stall conditions are computed and compared with pressure and particle image velocimetry (PIV experimental data, obtaining, in general, consistent results. At low angles of attack, the aerodynamic behavior of all of the studied blade sections resembles the one from the corresponding 2D airfoils. However, at high angles of attack, rotational effects lead to stall delay and/or lift enhancement at inboard positions. Such effects are shown to occur only in the presence of significant radial flows. Interestingly, the way in which rotational effects influence the aerodynamics of the MEXICO blades differs qualitatively in certain aspects from the descriptions found in the literature about this topic. The presented results provide new insights that are useful for the development of advanced and physically-sound correction models.

Family resemblance in fat intake, nutrition attitudes and beliefs : a study among three generations of women

NARCIS (Netherlands)

Stafleu, A.

1994-01-01

In this thesis nutrition attitudes, beliefs, and fat intake in three generations of women are described. The aim of the study was twofold: the development of methods, and to study family resemblance in food habits. Based on literature study and qualitative pilot studies a questionnaire on

The effects of NACA 0012 airfoil modification on aerodynamic performance improvement and obtaining high lift coefficient and post-stall airfoil

Science.gov (United States)

Sogukpinar, Haci

2018-02-01

In this study, aerodynamic performances of NACA 0012 airfoils with distinct modification are numerically investigated to obtain high lift coefficient and post-stall airfoils. NACA 0012 airfoil is divided into two part thought chord line then suction sides kept fixed and by changing the thickness of the pressure side new types of airfoil are created. Numerical experiments are then conducted by varying thickness of NACA 0012 from lower surface and different relative thicknesses asymmetrical airfoils are modified and NACA 0012-10, 0012-08, 0012-07, 0012-06, 0012-04, 0012-03, 0012-02, 0012-01 are created and simulated by using COMSOL software.

ROMANIA’S FISCAL STRUCTURE IN VIEW OF EURO ADOPTION. A MULTIDIMENSIONAL ANALYSIS

Directory of Open Access Journals (Sweden)

Maria-Isadora Lazar

2014-04-01

Full Text Available The aim of this paper is to conclude whether the adoption of the single currency induced a trend of structural resemblance, and if so, to determine groups of countries with similar fiscal structures inside the Euro Area. Taking into consideration total revenues, indirect taxation, direct taxation and social contributions, we analyzed primary data and completed it with multidimensional classification. Having in view Romania’s objective of adopting Euro currency we aim to establish to which subgroup is Romania more similar in terms of fiscal structure and whether this resemblance enhanced since the accession to the European Union.

Active Control Technology for Enhanced Performance Operational Capabilities of Military Aircraft, Land Vehicles and Sea Vehicles (Technologies des systemes a commandes actives pour l'amelioration des performances operationnelles des aeronefs militaires, des vehicules terrestres et des vehicules maritimes)

National Research Council Canada - National Science Library

2001-01-01

... Technology For Load Alleviation, Active Elements for Structural Design, Active Materials and Applications, Applications Overview, Compressor Stall/ Surge - Measurements, Compressor Stall/Surge - Control...

Gastrointestinal symptoms resembling ulcerative proctitis caused by larvae of the drone fly Eristalis tenax.

Science.gov (United States)

Desoubeaux, Guillaume; Gaillard, Julien; Borée-Moreau, Diane; Bailly, Éric; Andres, Christian R; Chandenier, Jacques

2014-04-01

We report a case of facultative intestinal myiasis due to larvae of the drone fly Eristalis tenax, also named the rat-tailed maggots. The development of larvae in the lower bowel was responsible for non-specific gastrointestinal symptoms that resembled ulcerative proctitis. The diagnosis was established upon the observation of four spontaneously excreted mobile larvae. The definite identification of the E. tenax species was made possible by scanning electron microscopy. The clinical outcome was satisfactory.

Structure of the thioredoxin-fold domain of human phosducin-like protein 2

International Nuclear Information System (INIS)

Lou, Xiaochu; Bao, Rui; Zhou, Cong-Zhao; Chen, Yuxing

2009-01-01

The X-ray crystal structure of the Trx-fold domain of hPDCL2 was solved at 2.70 Å resolution and resembled the Trx-fold domain of rat phosducin. Human phosducin-like protein 2 (hPDCL2) has been identified as belonging to subgroup II of the phosducin (Pdc) family. The members of this family share an N-terminal helix domain and a C-terminal thioredoxin-fold (Trx-fold) domain. The X-ray crystal structure of the Trx-fold domain of hPDCL2 was solved at 2.70 Å resolution and resembled the Trx-fold domain of rat phosducin. Comparative structural analysis revealed the structural basis of their putative functional divergence

Numerical modeling of a pitch oscillating S809 airfoil dynamic stall in 2D with application to a horizontal axis wind turbine

Energy Technology Data Exchange (ETDEWEB)

Gharali, K.; Johnson, D.A. [Waterloo Univ., ON (Canada). Dept. of Mechanical and Mechatronics Engineering, Wind Energy Group

2010-07-01

Natural wind can sometimes have a strong wind shear that causes the Dynamic Stall (DS) phenomena which may result in dynamic loads and varying lift coefficients. The DS phenomena cannot be prevented in horizontal axis wind turbines (HAWTs). Therefore, it is necessary to study the unsteady aerodynamics in order to modify common wind turbine rotor designs. This paper reported on a study that investigated the dynamic flow fields around an oscillating 2D S809 airfoil, representing the aerodynamic characteristics of HAWT airfoils for dynamic stall conditions. A computational fluid dynamic (CFD) flow solver package with Fluent was used with different turbulence models, notably the Spalart-Allmaras and Detached Eddy Simulation (DES) methods. A sliding mesh is commonly used in numerical methods for simulating an oscillating foil, but sliding meshes suffer from mesh generation complexity and increased computational time. In this study, instead of a sinusoidally pitching airfoil, the direction of the far-field flow was changed according to a user-defined function in the software to simulate a proper angle of attack for the boundary conditions in each time step. This strategy helped to decrease processing time. The simulation results were in good agreement with experimental data and the Beddoes-Leishman model results. The DES method for unsteady 2D flow was not recommended. It was concluded that the Fluent package is time efficient, reliable and economic for the wind turbine industry. 17 refs., 3 figs.

MOF Suppresses Replication Stress and Contributes to Resolution of Stalled Replication Forks.

Science.gov (United States)

Singh, Dharmendra Kumar; Pandita, Raj K; Singh, Mayank; Chakraborty, Sharmistha; Hambarde, Shashank; Ramnarain, Deepti; Charaka, Vijaya; Ahmed, Kazi Mokim; Hunt, Clayton R; Pandita, Tej K

2018-03-15

The human MOF (hMOF) protein belongs to the MYST family of histone acetyltransferases and plays a critical role in transcription and the DNA damage response. MOF is essential for cell proliferation; however, its role during replication and replicative stress is unknown. Here we demonstrate that cells depleted of MOF and under replicative stress induced by cisplatin, hydroxyurea, or camptothecin have reduced survival, a higher frequency of S-phase-specific chromosome damage, and increased R-loop formation. MOF depletion decreased replication fork speed and, when combined with replicative stress, also increased stalled replication forks as well as new origin firing. MOF interacted with PCNA, a key coordinator of replication and repair machinery at replication forks, and affected its ubiquitination and recruitment to the DNA damage site. Depletion of MOF, therefore, compromised the DNA damage repair response as evidenced by decreased Mre11, RPA70, Rad51, and PCNA focus formation, reduced DNA end resection, and decreased CHK1 phosphorylation in cells after exposure to hydroxyurea or cisplatin. These results support the argument that MOF plays an important role in suppressing replication stress induced by genotoxic agents at several stages during the DNA damage response. Copyright © 2018 American Society for Microbiology.

[Synchronous Double Cancer Involving Gastric Cancer Resembling a Submucosal Tumor with Stenosis in the Pylorus and Ascending Colon Cancer - A Case Report].

Science.gov (United States)

Miyauchi, Tatsuomi; Miyaki, Akira; Ida, Arika; Kishibe, Saki; Yamaguchi, Kentaro; Shiozawa, Shunichi; Usui, Takebumi; Kuhara, Kotaro; Kono, Teppei; Naritaka, Yoshihiko

2016-11-01

An 82-year-old woman presented to our hospital with a complaint of frequent vomiting. She was admitted for intensive examination and treatment. Abdominal computed tomography revealed that her stomach was severely expanded, and the wall of the ascending colon was thickened throughout its circumference. Upper gastrointestinal endoscopy uncovered severe stenosis in the pylorus and an elevated lesion resembling a submucosal tumor on the posterior wall of the pylorus. Biopsies of the lesion revealed that it was of Group 1. On colonoscopy, type 2 cancer was found in the ascending colon throughout the circumference, and the biopsies revealed that it was of Group 5. Upper gastrointestinal endoscopy was repeated, and the same result was obtained. The possibility of malignancy could not be excluded; therefore, distal gastrectomy and right colectomy were performed. In terms of histopathology, both resected specimens displayed poorly differentiated adenocarcinoma; however, immunohistochemical studies revealed differences in staining at the two sites. The case was diagnosed as synchronous double cancer involving gastric cancer resembling a submucosal tumor with stenosis in the pylorus and ascending colon cancer. Gastric cancer resembling a submucosal tumor is usually difficult to diagnose on biopsy. If the endoscopic findings reveal an elevated lesion resembling a submucosal tumor with stenosis, then the possibility of carcinoma should be considered, and the most suitable treatment should be selected.

RekonFit - fit by reconstruction. Retrofitting of stall-controlled wind power systems; RekonFit - Fit durch Rekonstruktion. Verbesserungen fuer ihre stallgeregelte Windenergieanlage

Energy Technology Data Exchange (ETDEWEB)

Rosebrock, B. [RWE Piller GmbH, Osterode (Germany); Pfeiffer, K. [Erwin Peters GmbH, Hamburg (Germany)

2004-07-01

The improvements gained by retrofitting are summarized as follows: Reduction of servicing cost by abandoning terminal switching; reduction of loads on the powertrain and rotor blades; reduction of loads on electric components (main contactors and compensation); higher productivity as RekonFit MAF improves the overall productivity of stall-controlled wind power systems with terminal-switched asynchronous generators in low-wind operation; excellent function in low wind conditions with optimisation only in the lower stage (P

Crystal structure of MboIIA methyltransferase.

Science.gov (United States)

Osipiuk, Jerzy; Walsh, Martin A; Joachimiak, Andrzej

2003-09-15

DNA methyltransferases (MTases) are sequence-specific enzymes which transfer a methyl group from S-adenosyl-L-methionine (AdoMet) to the amino group of either cytosine or adenine within a recognized DNA sequence. Methylation of a base in a specific DNA sequence protects DNA from nucleolytic cleavage by restriction enzymes recognizing the same DNA sequence. We have determined at 1.74 A resolution the crystal structure of a beta-class DNA MTase MboIIA (M.MboIIA) from the bacterium Moraxella bovis, the smallest DNA MTase determined to date. M.MboIIA methylates the 3' adenine of the pentanucleotide sequence 5'-GAAGA-3'. The protein crystallizes with two molecules in the asymmetric unit which we propose to resemble the dimer when M.MboIIA is not bound to DNA. The overall structure of the enzyme closely resembles that of M.RsrI. However, the cofactor-binding pocket in M.MboIIA forms a closed structure which is in contrast to the open-form structures of other known MTases.

Combining different views of mammographic texture resemblance (MTR) marker of breast cancer risk

DEFF Research Database (Denmark)

Sun, S.; Karemore, Gopal; Chernoff, Konstantin

the subsequent 4 years whereas 245 cases had a diagnosis 2-4 years post mammography. We employed the MTR supervised texture learning framework to perform risk evaluation from a single mammography view. In the framework 20,000 pixels were sampled and classified by a kNN pixel classifier. A feature selection step......PURPOSE Mammographic density is a well established breast cancer risk factor. Texture analysis in terms of the Mammographoc Texture Resemblance (MTR) marker has recently shown to add to risk segregation. Hitherto only single view MTR analysis has been performed. Standard mammography examinations...

Ten years later: Evaluation of the effectiveness of 12.5% amitraz against a field population of Rhipicephalus (Boophilus) microplus using field studies, artificial infestation (Stall tests) and adult immersion tests.

Science.gov (United States)

Maciel, Willian Giquelin; Lopes, Welber Daniel Zanetti; Cruz, Breno Cayeiro; Gomes, Lucas Vinicius Costa; Teixeira, Weslen Fabrício Pires; Buzzulini, Carolina; Bichuette, Murilo Abud; Campos, Gabriel Pimentel; Felippelli, Gustavo; Soares, Vando Edésio; de Oliveira, Gilson Pereira; da Costa, Alvimar José

2015-12-15

Using field trials, artificial infestations (Stall tests) and in vitro adult immersion tests, the present study evaluated the acaricidal efficacy of 12.5% amitraz administered via whole body spraying against a Rhipicephalus (Boophilus) microplus population that did not have any contact with chemical products belonging to this acaricide family for 10 years (approximately 40 generations). Two natural infestation trials, two artificial infestation trials (Stall tests) and two adult immersion tests were performed in two different stages in 2005 and 2015. Between 2002 and 2015, the bovine herd of this property was formed by approximately 450 animals from the Simmental breed that were divided into nine paddocks formed by Cynodon dactylon (L.) Pers. For the natural infestation experiments in 2005 and 2015, we selected nearly 70 animals naturally infested with ticks from the same herd that belonged to the "São Paulo" farm located in São José do Rio Pardo, São Paulo, Brazil. Field studies were performed in the same paddock (9). To evaluate anti-R. (B.) microplus activity in the artificially infested cattle (Stall tests) and adult immersion tests, two experiments of each methodology were performed at CPPAR (the Center of Research in Animal Health located on the FCAV/UNESP campus in Jaboticabal, São Paulo, Brazil) in 2005 and 2015. R. (B.) microplus used in the artificial infestation, and adult immersion test experiments were obtained from paddocks 1-9 in 2005 and 2015 from the commercial farm where the field studies were performed. Based on the obtained results, it was possible to conclude that amitraz use in rotation with pyrethroids every 28 days for three consecutive years (2002-2004) previous to the beginning of the first trial (2005) was sufficient to generate a R. (B.) microplus strain resistant to amitraz. Moreover, using field trials, artificial infestations (Stall tests) and adult immersion tests, we verified that 40 generations of the tick species with no

Structural characterization and lipid composition of acquired cholesteatoma

DEFF Research Database (Denmark)

Bloksgaard, Maria; Svane-Knudsen, Viggo; Sørensen, Jens A

2012-01-01

HYPOTHESIS: The goal of this work is to characterize the morphology and lipid composition of acquired cholesteatoma. We hypothesize that constitutive lipid membranes are present in the cholesteatoma and resemble those found in human skin stratum corneum. METHODS: We performed a comparative...... noninvasive structural and lipid compositional study of acquired cholesteatoma and control human skin using multiphoton excitation fluorescence microscopy-related techniques and high-performance thin-layer chromatography. RESULTS: The structural arrangement of the cholesteatoma is morphologically invariant...... along a depth of more than 200 μm and resembles the stratum corneum of hyperorthokeratotic skin. Lipid compositional analyses of the cholesteatoma show the presence of all major lipid classes found in normal skin stratum corneum (ceramides, long chain fatty acids, and cholesterol). Consistent with this...

A Drosophila gene encoding a protein resembling the human β-amyloid protein precursor

International Nuclear Information System (INIS)

Rosen, D.R.; Martin-Morris, L.; Luo, L.; White, K.

1989-01-01

The authors have isolated genomic and cDNA clones for a Drosophila gene resembling the human β-amyloid precursor protein (APP). This gene produces a nervous system-enriched 6.5-kilobase transcript. Sequencing of cDNAs derived from the 6.5-kilobase transcript predicts an 886-amino acid polypeptide. This polypeptide contains a putative transmembrane domain and exhibits strong sequence similarity to cytoplasmic and extracellular regions of the human β-amyloid precursor protein. There is a high probability that this Drosophila gene corresponds to the essential Drosophila locus vnd, a gene required for embryonic nervous system development

The Correlation between Eating Utensils and Place of Sales in the Contamination of Escherichia coli in Food Sold at Campus Food Stalls

Directory of Open Access Journals (Sweden)

Dewi Susanna

2015-04-01

Full Text Available Up to now, in general, the safety of food that is sold at any canteens in the campuses, the eating utensils are handled and the food stalls are managed are still uncertain. This research was aimed to understand the correlation between the eating utensils handling and the contamination of Escherichia coli (E. coli in the food sold by the food vendors in the campus. The cross-sectional design research applied on the food stalls in the university campus in Depok with a total number of 173 consumers as respondents. The variables observed as independent variables were the sanitation of the eating utensils and the sanitation of the dining place. The examination method of the Most Probable Number (MPN for E. coli was conducted to assess the food’s hygiene. The data analyzed using the chi-square test and followed by the logistic regression. The result showed that more than half of the food samples (59.54% were contaminated by E. coli. The storage place of the eating utensils was most significantly correlated with the E. coli contamination of the served food with an OR=0.45 (0.21-0.87. Therefore, it is necessary to promote the awareness of this risk and reinforce supervision by the Health Authorities and by the management of the place of sales to provide guidance to the food vendors and to the consumers as well. Further research is recommended to observe the E. coli contamination through clean water, eating utensils, the hands of the consumers and the napkins used to wipe dry the eating utensils.

Taxa de gestação em fêmeas da raça Holandesa confinadas em free stall, no verão e inverno Gestation rate of Holstein females confined in free stall, during the summer and winter

Directory of Open Access Journals (Sweden)

M.F.A. Pires

2002-02-01

Full Text Available A taxa de gestação de vacas em lactação e de novilhas confinadas em free stall foi avaliada durante o inverno e o verão, nos anos de 1993, 1994 e 1995. A temperatura ambiente (TA e a umidade relativa do ar (UR foram acompanhadas diariamente, durante quatro meses de verão (dezembro a março e três meses de inverno (junho a agosto. Em cada estação mediram-se semanalmente às 9, 15 e 21h a temperatura retal (TR e a freqüência respiratória (FR de 50% das vacas em lactação, sorteadas ao acaso, separadas em quatro grupos de acordo com a produção de leite. A TA e o índice de temperatura e umidade (ITU médios foram mais elevados (P The gestation rate was used to evaluate the reproductive performance of dairy cows and heifers confined in a free stall barn during the winter and summer seasons of 1993, 1994 and 1995. The temperature (T and relative humidity (RH were monitored daily during the summer (December, January, February and March and winter (June, July and August. The rectal temperature (RT and respiration rate (RR were measured weekly at 9AM and 3 and 9PM, in each season, in 50% of the animals randomly selected and sorted in four groups based on their milk production. The averages of T and the temperature and humidity index (THI were higher in the summer (25.6ºC e 75.8 than in the winter (19.0ºC e 65.3, while the RH were the same in both seasons (80.0%. The averages of RT and RR were always higher in the summer and at 3PM when compared to 9AM RT and RR (39.47ºC and 64.76 mov/min vs 38.89ºC and 44.21 mov/min. Gestation rate for milking cows was smaller in summer than in the winter. Conversely 85.4% of heifers became pregnant during the summer and 78.5% during the winter season.

Virus-resembling nano-structures for near infrared fluorescence imaging of ovarian cancer HER2 receptors

Science.gov (United States)

Guerrero, Yadir A.; Bahmani, Baharak; Singh, Sheela P.; Vullev, Valentine I.; Kundra, Vikas; Anvari, Bahman

2015-10-01

Ovarian cancer remains the dominant cause of death due to malignancies of the female reproductive system. The capability to identify and remove all tumors during intraoperative procedures may ultimately reduce cancer recurrence, and lead to increased patient survival. The objective of this study is to investigate the effectiveness of an optical nano-structured system for targeted near infrared (NIR) imaging of ovarian cancer cells that over-express the human epidermal growth factor receptor 2 (HER2), an important biomarker associated with ovarian cancer. The nano-structured system is comprised of genome-depleted plant-infecting brome mosaic virus doped with NIR chromophore, indocyanine green, and functionalized at the surface by covalent attachment of monoclonal antibodies against the HER2 receptor. We use absorption and fluorescence spectroscopy, and dynamic light scattering to characterize the physical properties of the constructs. Using fluorescence imaging and flow cytometry, we demonstrate the effectiveness of these nano-structures for targeted NIR imaging of HER2 receptors in vitro. These functionalized nano-materials may provide a platform for NIR imaging of ovarian cancer.

Virus-resembling nano-structures for near infrared fluorescence imaging of ovarian cancer HER2 receptors

International Nuclear Information System (INIS)

Guerrero, Yadir A; Bahmani, Baharak; Vullev, Valentine I; Anvari, Bahman; Singh, Sheela P; Kundra, Vikas

2015-01-01

Ovarian cancer remains the dominant cause of death due to malignancies of the female reproductive system. The capability to identify and remove all tumors during intraoperative procedures may ultimately reduce cancer recurrence, and lead to increased patient survival. The objective of this study is to investigate the effectiveness of an optical nano-structured system for targeted near infrared (NIR) imaging of ovarian cancer cells that over-express the human epidermal growth factor receptor 2 (HER2), an important biomarker associated with ovarian cancer. The nano-structured system is comprised of genome-depleted plant-infecting brome mosaic virus doped with NIR chromophore, indocyanine green, and functionalized at the surface by covalent attachment of monoclonal antibodies against the HER2 receptor. We use absorption and fluorescence spectroscopy, and dynamic light scattering to characterize the physical properties of the constructs. Using fluorescence imaging and flow cytometry, we demonstrate the effectiveness of these nano-structures for targeted NIR imaging of HER2 receptors in vitro. These functionalized nano-materials may provide a platform for NIR imaging of ovarian cancer. (paper)

Socioeconomic and Demographic Factors for Spousal Resemblance in Obesity Status and Habitual Physical Activity in the United States

Directory of Open Access Journals (Sweden)

Hsin-Jen Chen

2014-01-01

Full Text Available Studies suggested that the married population has an increased risk of obesity and assimilation between spouses’ body weight. We examined what factors may affect married spouses’ resemblance in weight status and habitual physical activity (HPA and the association of obesity/HPA with spouses’ sociodemoeconomic characteristics and lifestyles. Medical Expenditure Panel Survey data of 11,403 adult married couples in the US during years 2006–2008 were used. Absolute-scale difference and relative-scale resemblance indices (correlation and kappa coefficients in body mass index (BMI and HPA were estimated by couples’ socioeconomic and demographic characteristics. We found that spousal difference in BMI was smaller for couples with a lower household income, for who were both unemployed, and for older spouses. Correlation coefficient between spouses’ BMI was 0.24, differing by race/ethnicity and family size. Kappa coefficient for weight status (obesity: BMI ≥ 30, overweight: 30 > BMI ≥ 25 was 0.11 and 0.35 for HPA. Never-working women’s husbands had lower odds of obesity than employed women’s husbands (OR = 0.69 (95% CI = 0.53–0.89. Men’s unemployment status was associated with wives’ greater odds of obesity (OR = 1.31 (95% CI = 1.01–1.71. HPA was associated with men’s employment status and income level, but not with women’s. The population representative survey showed that spousal resemblance in weight status and HPA varied with socioeconomic and demographic factors.

High-speed PIV applied to the wake of the NASA CRM model in ETW at high Re-number stall conditions for sub- and transonic speeds

OpenAIRE

Konrath, Robert; Geisler, Reinhard; Otter, Dirk; Philipp, Florian; Ehlers, Hauke; Agocs, Janos; Quest, Jürgen

2015-01-01

Within the framework of the EU project ESWIRP the Particle Image Velocimetry (PIV) using high-speed camera and laser has been used to measure the turbulent flow in the wake of a stalled aircraft wing. The measurements took place on the Common Research Model (CRM) provided by NASA in the pressurized cryogenic European Transonic Wind tunnel (ETW). A specific cryo-PIV system has been used and adapted for using high-speed PIV components under the cryogenic conditions of the wind tunnel faci...

Electrical conductivity of metal–carbon nanotube structures: Effect of ...

Indian Academy of Sciences (India)

Administrator

The electrical properties of asymmetric metal–carbon nanotube (CNT) structures have been studied using ... The models with asymmetric metal contacts and carbon nanotube bear resemblance to experimental ... ordinary mechanical strength.

Atypical mycobacterial infection resembles sporotrichosis in elderly patient

Directory of Open Access Journals (Sweden)

Siti Nurani Fauziah

2018-04-01

Full Text Available Atypical mycobacterial (AM infection is caused by Mycobacterium species other than M.tuberculosis. AM skin infection has clinical manifestations that resemble M. tuberculosis infection and deep fungal infection. Laboratory workup is necessary to confirm the diagnosis. An 83-year old female came with a painful lump and swelling on her right lower extremity since three months before admission. Physical examination revealed a plaque consisting, of multiple erythematous and hyperpigmented papules and nodules, diffuse erythematous lesion, and shallow ulcers partially covered with pus and crust. Histopathological features showed tuberculoid granuloma. Direct test and periodic acid-Schiff (PAS staining of the skin biopsy found no fungal element nor acid-fast bacilli (AFB. Culture and polymerase chain reaction (PCR of M. tuberculosis were negative. The working diagnosis was atypical mycobacterial infection and treatment with 450 mg rifampicin and 100 mg minocycline daily were administered accordingly. In two months observation following the treatment, the pain was no longer exist, the ulcers were completely healed, and some nodules were in the process of healing Among other Mycobacterium spp, M.marinum is the most common cause of AM infrections. Clinical manifestation of M. marinum infection may present as solitary or multiple nodules on the hands, feet, elbows and knees with sporotrichoid spreading patern. The diagnosis of AM was established based on clinical and laboratory examination. The diagnosis was also confirmed by good clinical response to minocycline and rifampicin.

Structural and gene expression analyses of uptake hydrogenases ...

Indian Academy of Sciences (India)

2013-10-01

Oct 1, 2013 ... subunits resemble the structures of known [NiFe] hydrogenases (Volbeda et al. 1995) ..... abundant lipid in Frankia cells and in nitrogen-fixing nodule tissue. .... Vignais PM and Billoud B 2007 Occurrence, classification, and.

From FRA to RFN, or How the Family Resemblance Approach Can Be Transformed for Science Curriculum Analysis on Nature of Science

Science.gov (United States)

Kaya, Ebru; Erduran, Sibel

2016-12-01

The inclusion of Nature of Science (NOS) in the science curriculum has been advocated around the world for several decades. One way of defining NOS is related to the family resemblance approach (FRA). The family resemblance idea was originally described by Wittgenstein. Subsequently, philosophers and educators have applied Wittgenstein's idea to problems of their own disciplines. For example, Irzik and Nola adapted Wittgenstein's generic definition of the family resemblance idea to NOS, while Erduran and Dagher reconceptualized Irzik and Nola's FRA-to-NOS by synthesizing educational applications by drawing on perspectives from science education research. In this article, we use the terminology of "Reconceptualized FRA-to-NOS (RFN)" to refer to Erduran and Dagher's FRA version which offers an educational account inclusive of knowledge about pedagogical, instructional, curricular and assessment issues in science education. Our motivation for making this distinction is rooted in the need to clarify the various accounts of the family resemblance idea.The key components of the RFN include the aims and values of science, methods and methodological rules, scientific practices, scientific knowledge as well as the social-institutional dimensions of science including the social ethos, certification, and power relations. We investigate the potential of RFN in facilitating curriculum analysis and in determining the gaps related to NOS in the curriculum. We analyze two Turkish science curricula published 7 years apart and illustrate how RFN can contribute not only to the analysis of science curriculum itself but also to trends in science curriculum development. Furthermore, we present an analysis of documents from USA and Ireland and contrast them to the Turkish curricula thereby illustrating some trends in the coverage of RFN categories. The results indicate that while both Turkish curricula contain statements that identify science as a cognitive-epistemic system, they

Fan cooling of the resting area in a free stalls dairy barn

Science.gov (United States)

Calegari, Ferdinando; Calamari, Luigi; Frazzi, Ermes

2014-08-01

This summer study evaluated the effect of providing additional fans (cooling) in the resting area within a free-stall dairy barn that had fans and sprinklers in the feeding area and paddock availability. Thirty cows were divided into two homogenous groups and kept in two pens: one had the resting area equipped with two fans (FAN) while no fans were added to the other resting area (CON). Microclimatic parameters, rectal temperature (RT), breathing rate (BR), milk yield, and milk pH traits were recorded. Time budgeting and the behaviour of the cows (time spent in the feeding area, standing and lying in other areas) were also recorded using digital video technology. Two slight-to-moderate heat waves were observed. During the hottest period the daily maximum temperature recorded was 33.5 °C and the daily maximum THI was 81.6. During this period, the BR and RT increased only slightly in both groups, with lower BR (n.s.) in FAN compared with CON. Milk yield was better maintained (n.s.) in FAN compared with CON during the hottest period. The FAN cows showed a greater ( P FAN and CON, respectively), whereas CON cows made greater ( P fans in the resting area improves cow comfort, which increases use of the resting area. The lying time results also suggest that the benefits of providing ventilation in the resting area might be more evident in barns where there is no paddock.

Nitriles at Silica Interfaces Resemble Supported Lipid Bilayers.

Science.gov (United States)

Berne, Bruce J; Fourkas, John T; Walker, Robert A; Weeks, John D

2016-09-20

Nitriles are important solvents not just for bulk reactions but also for interfacial processes such as separations, heterogeneous catalysis, and electrochemistry. Although nitriles have a polar end and a lipophilic end, the cyano group is not hydrophilic enough for these substances to be thought of as prototypical amphiphiles. This picture is now changing, as research is revealing that at a silica surface nitriles can organize into structures that, in many ways, resemble lipid bilayers. This unexpected organization may be a key component of unique interfacial behavior of nitriles that make them the solvents of choice for so many applications. The first hints of this lipid-bilayer-like (LBL) organization of nitriles at silica interfaces came from optical Kerr effect (OKE) experiments on liquid acetonitrile confined in the pores of sol-gel glasses. The orientational dynamics revealed by OKE spectroscopy suggested that the confined liquid is composed of a relatively immobile sublayer of molecules that accept hydrogen bonds from the surface silanol groups and an interdigitated, antiparallel layer that is capable of exchanging into the centers of the pores. This picture of acetonitrile has been borne out by molecular dynamics simulations and vibrational sum-frequency generation (VSFG) experiments. Remarkably, these simulations further indicate that the LBL organization is repeated with increasing disorder at least 20 Å into the liquid from a flat silica surface. Simulations and VSFG and OKE experiments indicate that extending the alkyl chain to an ethyl group leads to the formation of even more tightly packed LBL organization featuring entangled alkyl tails. When the alkyl portion of the molecule is a bulky t-butyl group, packing constraints prevent well-ordered LBL organization of the liquid. In each case, the surface-induced organization of the liquid is reflected in its interfacial dynamics. Acetonitrile/water mixtures are favored solvent systems for separations

Prion disease resembling frontotemporal dementia and parkinsonism linked to chromosome 17

Directory of Open Access Journals (Sweden)

Nitrini Ricardo

2001-01-01

Full Text Available OBJECTIVE: To compare the clinical features of a familial prion disease with those of frontotemporal dementia and parkinsonism linked to chromosome 17 (FTDP-17. BACKGROUND: Prion diseases are not usually considered in the differential diagnosis of FTDP-17, since familial Creutzfeldt-Jakob disease (CJD, the most common inherited prion disease, often manifests as a rapidly progressive dementia. Conversely, FTDP-17 usually has an insidious onset in the fifth decade, with abnormal behavior and parkinsonian features. METHOD: We present the clinical features of 12 patients from a family with CJD associated with a point mutation at codon 183 of the prion protein gene. RESULTS: The mean age at onset was 44.0 ± 3.7; the duration of the symptoms until death ranged from two to nine years. Behavioral disturbances were the predominant presenting symptoms. Nine patients were first seen by psychiatrists. Eight patients manifested parkinsonian signs. CONCLUSION: These clinical features bear a considerable resemblance to those described in FTDP-17.

Electrical conductivity of metal–carbon nanotube structures

Indian Academy of Sciences (India)

The electrical properties of asymmetric metal–carbon nanotube (CNT) structures have been studied using density functional theory and non-equilibrium Green's function method with Atomistix tool kit. The models with asymmetric metal contacts and carbon nanotube bear resemblance to experimental set-ups. The study ...

Sunflower Oil but Not Fish Oil Resembles Positive Effects of Virgin Olive Oil on Aged Pancreas after Life-Long Coenzyme Q Addition

Science.gov (United States)

González-Alonso, Adrián; Ramírez-Tortosa, César L.; Varela-López, Alfonso; Roche, Enrique; Arribas, María I.; Ramírez-Tortosa, M. Carmen; Giampieri, Francesca; Ochoa, Julio J.; Quiles, José L.

2015-01-01

An adequate pancreatic structure is necessary for optimal organ function. Structural changes are critical in the development of age-related pancreatic disorders. In this context, it has been reported that different pancreatic compartments from rats were affected according to the fat composition consumed. Since there is a close relationship between mitochondria, oxidative stress and aging, an experimental approach has been developed to gain more insight into this process in the pancreas. A low dosage of coenzyme Q was administered life-long in rats in order to try to prevent pancreatic aging-related alterations associated to some dietary fat sources. According to that, three groups of rats were fed normocaloric diets containing Coenzyme Q (CoQ) for two years, where virgin olive, sunflower, or fish oil was included as unique fat source. Pancreatic samples for microscopy and blood samples were collected at the moment of euthanasia. The main finding is that CoQ supplementation gives different results according to fat used in diet. When sunflower oil was the main fat in the diet, CoQ supplementation seems to improve endocrine pancreas structure and in particular β-cell mass resembling positive effects of virgin olive oil. Conversely, CoQ intake does not seem to improve the structural alterations of exocrine compartment previously observed in fish oil fed rats. Therefore CoQ may improve pancreatic alterations associated to the chronic intake of some dietary fat sources. PMID:26426013

Sunflower Oil but Not Fish Oil Resembles Positive Effects of Virgin Olive Oil on Aged Pancreas after Life-Long Coenzyme Q Addition

Directory of Open Access Journals (Sweden)

Adrián González-Alonso

2015-09-01

Full Text Available An adequate pancreatic structure is necessary for optimal organ function. Structural changes are critical in the development of age-related pancreatic disorders. In this context, it has been reported that different pancreatic compartments from rats were affected according to the fat composition consumed. Since there is a close relationship between mitochondria, oxidative stress and aging, an experimental approach has been developed to gain more insight into this process in the pancreas. A low dosage of coenzyme Q was administered life-long in rats in order to try to prevent pancreatic aging-related alterations associated to some dietary fat sources. According to that, three groups of rats were fed normocaloric diets containing Coenzyme Q (CoQ for two years, where virgin olive, sunflower, or fish oil was included as unique fat source. Pancreatic samples for microscopy and blood samples were collected at the moment of euthanasia. The main finding is that CoQ supplementation gives different results according to fat used in diet. When sunflower oil was the main fat in the diet, CoQ supplementation seems to improve endocrine pancreas structure and in particular β-cell mass resembling positive effects of virgin olive oil. Conversely, CoQ intake does not seem to improve the structural alterations of exocrine compartment previously observed in fish oil fed rats. Therefore CoQ may improve pancreatic alterations associated to the chronic intake of some dietary fat sources.

Design of a 21 m blade with Risø-A1 airfoils for active stall controlled wind turbines

DEFF Research Database (Denmark)

Fuglsang, Peter; Sangill, O.; Hansen, P.

2002-01-01

This is the final report, from the project, "Design of a Rotor/Airfoil Family for Active Stall-regulated Wind Turbines by Use of Multi-point Optimization". It describes the full scale testing of a 21 m wind turbine blade specially designed for active stallregulation. Design objectives were...... increased ratio of produced energy to turbine loads and more stable power control characteristics. Both were taken directly into account during the design of the blade using numerical optimization. The blade used theRisø-A1 airfoil family, which was specially designed for operation on wind turbine blades....... The new blade was designed to replace the LM 21.0P blade. A measurement campaign was carried out simultaneously on two identical adjacent wind turbines where onehad the new blades and the other had LM 21.0P blades. Power and loads including blade section moments for the new blades were measured to assess...

Why commercialization of gene therapy stalled; examining the life cycles of gene therapy technologies.

Science.gov (United States)

Ledley, F D; McNamee, L M; Uzdil, V; Morgan, I W

2014-02-01

This report examines the commercialization of gene therapy in the context of innovation theories that posit a relationship between the maturation of a technology through its life cycle and prospects for successful product development. We show that the field of gene therapy has matured steadily since the 1980s, with the congruent accumulation of >35 000 papers, >16 000 US patents, >1800 clinical trials and >$4.3 billion in capital investment in gene therapy companies. Gene therapy technologies comprise a series of dissimilar approaches for gene delivery, each of which has introduced a distinct product architecture. Using bibliometric methods, we quantify the maturation of each technology through a characteristic life cycle S-curve, from a Nascent stage, through a Growing stage of exponential advance, toward an Established stage and projected limit. Capital investment in gene therapy is shown to have occurred predominantly in Nascent stage technologies and to be negatively correlated with maturity. Gene therapy technologies are now achieving the level of maturity that innovation research and biotechnology experience suggest may be requisite for efficient product development. Asynchrony between the maturation of gene therapy technologies and capital investment in development-focused business models may have stalled the commercialization of gene therapy.

Imaging manifestations of acquired elastopathy resembling pseudoxanthoma elasticum in patients with beta thalassaemia major and sickle cell disease

International Nuclear Information System (INIS)

Narayana, Harish; Cheng, Ken; Lau, Ken; Harish, Radhika; Bowden, Donald K.

2016-01-01

Development of an acquired systemic elastopathy resembling pseudoxanthoma elasticum in patients with chronic haemoglobinopathies such as beta thalassaemia major and sickle cell disease is well documented. There is paucity of any comprehensive literature on the radiological manifestations of this entity. This pictorial review aims to describe and illustrate the multi system and multi modality imaging findings of this condition.

What's in a child's face? : effects of facial resemblance, love withdrawal, empathy and context on behavioral and neural responses

NARCIS (Netherlands)

Heckendorf, E.

2018-01-01

The aim of this thesis is to increase our knowledge of individual differences in the neural processing and appraisal of children’s faces that differ in their degree of resemblance with the participant’s face. Chapter 2 focuses on participants’ neural responses to child faces that differ in

Mammographic Texture Resemblance generalizes as an independent risk factor of breast cancer

DEFF Research Database (Denmark)

Chernoff, Konstantin; Christopher, S G; Karemore, Gopal

PURPOSE Breast density has been established as a risk factor of breast cancer in numerous studies. Mammographic Texture Resemblance (MTR) has shown to be a density independent risk factor, but only on a single study. We examine if the statistics of the texture recorded in one study generalize...... as an independent risk factor in an unrelated cohort. METHOD AND MATERIALS The statistics of texture were recorded in digitalized film-mammograms of one 4-year prospective study (S1, Dutch screening program) of 245 breast cancers and 250 matched controls. From an independent cohort study (S2, Mayo Mammography...... Health Study cohort) 226 incident breast cancer cases diagnosed through 2008 and 442 matched controls (on age) were used for scoring screening digitized mammograms that were ascertained years prior to diagnosis 1993-2006. Mammographic percent density (PD), using Cumulus, and other major risk factors were...

Vaginal Microbiota of Adolescent Girls Prior to the Onset of Menarche Resemble Those of Reproductive-Age Women

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Hickey, Roxana J.; Zhou, Xia; Settles, Matthew L.; Erb, Julie; Malone, Kristin; Hansmann, Melanie A.; Shew, Marcia L.; Van Der Pol, Barbara

2015-01-01

ABSTRACT Puberty is an important developmental stage wherein hormonal shifts mediate the physical and physiological changes that lead to menarche, but until now, the bacterial composition of vaginal microbiota during this period has been poorly characterized. We performed a prospective longitudinal study of perimenarcheal girls to gain insight into the timing and sequence of changes that occur in the vaginal and vulvar microbiota during puberty. The study enrolled 31 healthy, premenarcheal girls between the ages of 10 and 12 years and collected vaginal and vulvar swabs quarterly for up to 3 years. Bacterial composition was characterized by Roche 454 pyrosequencing and classification of regions V1 to V3 of 16S rRNA genes. Contrary to expectations, lactic acid bacteria, primarily Lactobacillus spp., were dominant in the microbiota of most girls well before the onset of menarche in the early to middle stages of puberty. Gardnerella vaginalis was detected at appreciable levels in approximately one-third of subjects, a notable finding considering that this organism is commonly associated with bacterial vaginosis in adults. Vulvar microbiota closely resembled vaginal microbiota but often exhibited additional taxa typically associated with skin microbiota. Our findings suggest that the vaginal microbiota of girls begin to resemble those of adults well before the onset of menarche. PMID:25805726

Escova dental e dedeira na remoção da placa bacteriana dental em cães The dental brush and thumb-stall in the removal of the dental plaque in dogs

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Tânia Berbert Ferreira Lima

2004-02-01

Full Text Available A placa bacteriana é fator primário na formação de gengivite, cálculo dentário, halitose e doença periodontal. Objetivou-se avaliar a quantidade de placa bacteriana dental removida pela escova dental e dedeira. Foram utilizados 60 cães machos e fêmeas de diferentes raças, idade e peso, divididos em dois grupos. O índice Logan & Boyce foi utilizados para quantificar a placa bacteriana antes e após a escovação. Observou-se diferença estatística (p0,05 entre a utilização da escova dental e a dedeira.The dental plaque is the primary factor for gingivitis formation, dental calculus, oral malodor and periodontal disease. To evaluate the amount of dental plaque removed by the dental brush and thumb-stall, 60 male and female dogs of different races, age and weight were divided in two groups and studies. The index of Logan & Boyce was used to quantify the dental plaque before and after the toothbrush. Statistical difference was observed (p 0.05 between the use of the dental brush and the thumb-stall.

Resemblance in dietary intakes between urban low-income African American adolescents and their mothers: The HEALTH-KIDS Study

Science.gov (United States)

Wang, Youfa; Li, Ji; Caballero, Benjamin

2009-01-01

Objectives To examine the association and predictors of dietary intake resemblance between urban low-income African American adolescents and their mothers. Methods Detailed dietary data collected from 121 child-parent pairs in Chicago in Fall 2003 were used. The association was assessed using correlation coefficients, kappa, and percentage of agreement, and logistic regression models. Results Overall, the association was weak as indicated by correlations and other measures. None of the mother-son correlations for nutrients and food groups were greater than 0.20. Mother-daughter pairs had stronger correlations (0.26 for energy and 0.30 for fat). The association was stronger in normal weight- than overweight or obese mothers. Logistic models showed that mother being a current smoker, giving child more pocket money, and allowing child to eat or purchase snacks without parental permission or presence predicted a higher probability of resemblance in undesirable eating patterns, such as high-energy, high-fat, and high-snack intakes (p<0.05). Conclusions Mother-child diet association was generally weak, and varied considerably across groups and intake variables in this homogenous population. Some maternal characteristics seem to affect the association. PMID:19103323

Parametric analyses for synthetic jet control on separation and stall over rotor airfoil

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Zhao Guoqing

2014-10-01

Full Text Available Numerical simulations are performed to investigate the effects of synthetic jet control on separation and stall over rotor airfoils. The preconditioned and unsteady Reynolds-averaged Navier–Stokes equations coupled with a k − ω shear stream transport turbulence model are employed to accomplish the flowfield simulation of rotor airfoils under jet control. Additionally, a velocity boundary condition modeled by a sinusoidal function is developed to fulfill the perturbation effect of periodic jets. The validity of the present CFD procedure is evaluated by the simulated results of an isolated synthetic jet and the jet control case for airfoil NACA0015. Then, parametric analyses are conducted specifically for an OA213 rotor airfoil to investigate the effects of jet parameters (forcing frequency, jet location and momentum coefficient, jet direction, and distribution of jet arrays on the control effect of the aerodynamic characteristics of a rotor airfoil. Preliminary results indicate that the efficiency of jet control can be improved with specific frequencies (the best lift-drag ratio at F+ = 2.0 and jet angles (40° or 75° when the jets are located near the separation point of the rotor airfoil. Furthermore, as a result of a suitable combination of jet arrays, the lift coefficient of the airfoil can be improved by nearly 100%, and the corresponding drag coefficient decreased by 26.5% in comparison with the single point control case.

Guinea-pig interpubic joint (symphysis pubica relaxation at parturition: Underlying cellular processes that resemble an inflammatory response

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Muñoz-de-Toro Mónica

2003-11-01

Full Text Available Abstract Background At term, cervical ripening in coordination with uterine contractions becomes a prerequisite for a normal vaginal delivery. Currently, cervical ripening is considered to occur independently from uterine contractions. Many evidences suggest that cervical ripening resembles an inflammatory process. Comparatively little attention has been paid to the increased flexibility of the pelvic symphysis that occurs in many species to enable safe delivery. The aim of this study was to investigate whether the guinea-pig interpubic joint relaxation process observed during late pregnancy and parturition resembles an inflammatory process. Methods Samples of pubic symphysis were taken from pregnant guinea-pigs sacrificed along gestation, parturition and postpartum. Serial sections of paraffin-embedded tissues were used to measure the interpubic distance on digitalized images, stained with Giemsa to quantify leukocyte infiltration and to describe the vascular area changes, or studied by the picrosirius-polarization method to evaluate collagen remodeling. P4 and E2 serum levels were measured by a sequential immunometric assay. Results Data showed that the pubic relaxation is associated with an increase in collagen remodeling. In addition, a positive correlation between E2 serum levels and the increase in the interpubic distance was found. On the other hand, a leukocyte infiltration in the interpubic tissue around parturition was described, with the presence of almost all inflammatory cells types. At the same time, histological images show an increase in vascular area (angiogenesis. Eosinophils reached their highest level immediately before parturition; whereas for the neutrophilic and mononuclear infiltration higher values were recorded one day after parturition. Correlation analysis showed that eosinophils and mononuclear cells were positively correlated with E2 levels, but only eosinophilic infiltration was associated with collagen remodeling

Extended retroperitoneal necrotizing fasciitis with genital involvement, resembling fournier gangrene.

Science.gov (United States)

Sugimoto, Motokazu; Matsuura, Kenji; Takayama, Hiroshi; Kayo, Munefumi; Ie, Tomotsugu

2010-10-01

Necrotizing fasciitis is a serious infection that originates in the subcutaneous tissues. Although many reports have been published about necrotizing infections of other anatomical sites, retroperitoneal necrotizing soft tissue infection is a rare entity that has been described in only a few case reports. The etiology and clinical course of retroperitoneal necrotizing fasciitis can be variable and it is often difficult to identify the etiology of the infective process. We report a 58-year-old man with rapidly progressive, gas-producing, necrotizing inflammation in the retroperitoneum, complicated with genital involvement resembling Fournier gangrene. The patient was managed successfully by aggressive drainage, debridement, and sequential laparotomies to track and control the extensive necrosis of the retroperitoneum and perineum, in addition to systemic care to control sepsis. After his general condition stabilized, early rectosigmoid adenocarcinoma was identified and resected curatively. He remained well at follow up, six months after discharge. In retrospect, the trigger of the disease process was unclear. Although it was believed possibly to be due to the colon lesion, adenocarcinoma of the rectosigmoid colon was identified and the patient was managed successfully. Similar to necrotizing infections at other anatomical sites, early diagnosis and timely surgical intervention and systemic antimicrobial therapy are mandatory for treating patients with retroperitoneal necrotizing fasciitis.

A combined cryo-EM and molecular dynamics approach reveals the mechanism of ErmBL-mediated translation arrest

Science.gov (United States)

Arenz, Stefan; Bock, Lars V.; Graf, Michael; Innis, C. Axel; Beckmann, Roland; Grubmüller, Helmut; Vaiana, Andrea C.; Wilson, Daniel N.

2016-07-01

Nascent polypeptides can induce ribosome stalling, regulating downstream genes. Stalling of ErmBL peptide translation in the presence of the macrolide antibiotic erythromycin leads to resistance in Streptococcus sanguis. To reveal this stalling mechanism we obtained 3.6-Å-resolution cryo-EM structures of ErmBL-stalled ribosomes with erythromycin. The nascent peptide adopts an unusual conformation with the C-terminal Asp10 side chain in a previously unseen rotated position. Together with molecular dynamics simulations, the structures indicate that peptide-bond formation is inhibited by displacement of the peptidyl-tRNA A76 ribose from its canonical position, and by non-productive interactions of the A-tRNA Lys11 side chain with the A-site crevice. These two effects combine to perturb peptide-bond formation by increasing the distance between the attacking Lys11 amine and the Asp10 carbonyl carbon. The interplay between drug, peptide and ribosome uncovered here also provides insight into the fundamental mechanism of peptide-bond formation.

Structure based hypothesis of a mitochondrial ribosome rescue mechanism

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Huynen Martijn A

2012-05-01

Full Text Available Abstract Background mtRF1 is a vertebrate mitochondrial protein with an unknown function that arose from a duplication of the mitochondrial release factor mtRF1a. To elucidate the function of mtRF1, we determined the positions that are conserved among mtRF1 sequences but that are different in their mtRF1a paralogs. We subsequently modeled the 3D structure of mtRF1a and mtRF1 bound to the ribosome, highlighting the structural implications of these differences to derive a hypothesis for the function of mtRF1. Results Our model predicts, in agreement with the experimental data, that the 3D structure of mtRF1a allows it to recognize the stop codons UAA and UAG in the A-site of the ribosome. In contrast, we show that mtRF1 likely can only bind the ribosome when the A-site is devoid of mRNA. Furthermore, while mtRF1a will adopt its catalytic conformation, in which it functions as a peptidyl-tRNA hydrolase in the ribosome, only upon binding of a stop codon in the A-site, mtRF1 appears specifically adapted to assume this extended, peptidyl-tRNA hydrolyzing conformation in the absence of mRNA in the A-site. Conclusions We predict that mtRF1 specifically recognizes ribosomes with an empty A-site and is able to function as a peptidyl-tRNA hydrolase in those situations. Stalled ribosomes with empty A-sites that still contain a tRNA bound to a peptide chain can result from the translation of truncated, stop-codon less mRNAs. We hypothesize that mtRF1 recycles such stalled ribosomes, performing a function that is analogous to that of tmRNA in bacteria. Reviewers This article was reviewed by Dr. Eugene Koonin, Prof. Knud H. Nierhaus (nominated by Dr. Sarah Teichmann and Dr. Shamil Sunyaev.

Fetuin-A/albumin-mineral complexes resembling serum calcium granules and putative nanobacteria: demonstration of a dual inhibition-seeding concept.

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Cheng-Yeu Wu

2009-11-01

Full Text Available Serum-derived granulations and purported nanobacteria (NB are pleomorphic apatite structures shown to resemble calcium granules widely distributed in nature. They appear to be assembled through a dual inhibitory-seeding mechanism involving proteinaceous factors, as determined by protease (trypsin and chymotrypsin and heat inactivation studies. When inoculated into cell culture medium, the purified proteins fetuin-A and albumin fail to induce mineralization, but they will readily combine with exogenously added calcium and phosphate, even in submillimolar amounts, to form complexes that will undergo morphological transitions from nanoparticles to spindles, films, and aggregates. As a mineralization inhibitor, fetuin-A is much more potent than albumin, and it will only seed particles at higher mineral-to-protein concentrations. Both proteins display a bell-shaped, dose-dependent relationship, indicative of the same dual inhibitory-seeding mechanism seen with whole serum. As ascertained by both seeding experiments and gel electrophoresis, fetuin-A is not only more dominant but it appears to compete avidly for nanoparticle binding at the expense of albumin. The nanoparticles formed in the presence of fetuin-A are smaller than their albumin counterparts, and they have a greater tendency to display a multi-layered ring morphology. In comparison, the particles seeded by albumin appear mostly incomplete, with single walls. Chemically, spectroscopically, and morphologically, the protein-mineral particles resemble closely serum granules and NB. These particles are thus seen to undergo an amorphous to crystalline transformation, the kinetics and completeness of which depend on the protein-to-mineral ratios, with low ratios favoring faster conversion to crystals. Our results point to a dual inhibitory-seeding, de-repression model for the assembly of particles in supersaturated solutions like serum. The presence of proteins and other inhibitory factors tend

Stalled repair of lesions when present within a clustered DNA damage site

International Nuclear Information System (INIS)

Lomax, M.E.; Cunniffe, S.; O'Neill, P.

2003-01-01

Ionising radiation produces clustered DNA damages (two or more lesions within one or two helical turns of the DNA) which could challenge the repair mechanism(s) of the cell. Using purified base excision repair (BER) enzymes and synthetic oligonucleotides a number of recent studies have established the excision of a lesion within clustered damage sites is compromised. Evidence will be presented that the efficiency of repair of lesions within a clustered DNA damage site is reduced, relative to that of the isolated lesions, since the lifetime of both lesions is extended by up to four fold. Simple clustered damage sites, comprised of single-strand breaks, abasic sites and base damages, one or five bases 3' or 5' to each other, were synthesised in oligonucleotides and repair carried out in mammalian cell nuclear extracts. The rate of repair of the single-strand break/abasic site within these clustered damage sites is reduced, mainly due to inhibition of the DNA ligase. The mechanism of repair of the single-strand break/abasic site shows some asymmetry. Repair appears to be by the short-patch BER pathway when the lesions are 5' to each other. In contrast, when the lesions are 3' to each other repair appears to proceed along the long-patch BER pathway. The lesions within the cluster are processed sequentially, the single-strand break/abasic site being repaired before excision of 8-oxoG, limiting the formation of double-strand breaks to <2%. Stalled processing of clustered DNA damage extends the lifetime of the lesions to an extent that could have biological consequences, e.g. if the lesions are still present during transcription and/or at replication mutations could arise

Evaluation of free-stall mattress bedding treatments to reduce mastitis bacterial growth

Energy Technology Data Exchange (ETDEWEB)

Kristula, M A; Dou, Z; Toth, J D; Smith, B I; Harvey, N; Sabo, M [University of Penn, Kennett Square, PA (United States)

2008-05-15

Bacterial counts were compared in free-stall mattresses and teat ends exposed to 5 treatments in a factorial study design on 1 dairy farm. Mattresses in five 30-cow groups were subjected to 1 of 5 bedding treatments every other day: 0.5 kg of hydrated limestone, 120 mL of commercial acidic conditioner, 1 kg of coal fly ash, 1 kg of kiln-dried wood shavings, and control (no bedding). Counts of coliforms, Klebsiella spp., Escherichia coli, and Streptococcus spp. were lowest on mattresses bedded with lime. Mattresses bedded with the commercial acidic conditioner had the next lowest counts for coliforms, Klebsiella spp., and Streptococcus spp. Wood shavings and the no-bedding control had the highest counts for coliform and Klebsiella spp. Compared with wood shavings or control, fly ash reduced the counts of coliforms, whereas for the other 3 bacterial groups, the reduction was not always significant. Streptococcus spp. counts were greatest in the control group and did not differ among the shavings and fly ash groups. Teat swab results indicated that hydrated lime was the only bedding treatment that significantly decreased the counts of both coliforms and Klebsiella spp. There were no differences in Streptococcus spp. numbers on the teats between any of the bedding treatments. Bacterial populations grew steadily on mattresses and were generally higher at 36 to 48 h than at 12 to 24 h, whereas bacterial populations on teats grew rapidly by 12 h and then remained constant. Hydrated lime was the only treatment that significantly reduced bacterial counts on both mattresses and teat ends, but it caused some skin irritation.

Structure of a Novel DNA-binding Domain of Helicase-like Transcription Factor (HLTF) and Its Functional Implication in DNA Damage Tolerance.

Science.gov (United States)

Hishiki, Asami; Hara, Kodai; Ikegaya, Yuzu; Yokoyama, Hideshi; Shimizu, Toshiyuki; Sato, Mamoru; Hashimoto, Hiroshi

2015-05-22

HLTF (helicase-like transcription factor) is a yeast RAD5 homolog found in mammals. HLTF has E3 ubiquitin ligase and DNA helicase activities, and plays a pivotal role in the template-switching pathway of DNA damage tolerance. HLTF has an N-terminal domain that has been designated the HIRAN (HIP116 and RAD5 N-terminal) domain. The HIRAN domain has been hypothesized to play a role in DNA binding; however, the structural basis of, and functional evidence for, the HIRAN domain in DNA binding has remained unclear. Here we show for the first time the crystal structure of the HIRAN domain of human HLTF in complex with DNA. The HIRAN domain is composed of six β-strands and two α-helices, forming an OB-fold structure frequently found in ssDNA-binding proteins, including in replication factor A (RPA). Interestingly, this study reveals that the HIRAN domain interacts with not only with a single-stranded DNA but also with a duplex DNA. Furthermore, the structure unexpectedly clarifies that the HIRAN domain specifically recognizes the 3'-end of DNA. These results suggest that the HIRAN domain functions as a sensor to the 3'-end of the primer strand at the stalled replication fork and that the domain facilitates fork regression. HLTF is recruited to a damaged site through the HIRAN domain at the stalled replication fork. Furthermore, our results have implications for the mechanism of template switching. © 2015 by The American Society for Biochemistry and Molecular Biology, Inc.

Flow Structure and Surface Topology on a UCAV Planform

Science.gov (United States)

Elkhoury, Michel; Yavuz, Metin; Rockwell, Donald

2003-11-01

Flow past a X-45 UCAV planform involves the complex generation and interaction of vortices, their breakdown and occurrence of surface separation and stall. A cinema technique of high-image-density particle image velocimetry, in conjunction with dye visualization, allows characterization of the time-averaged and instantaneous states of the flow, in terms of critical points of the near-surface streamlines. These features are related to patterns of surface normal vorticity and velocity fluctuation. Spectral analysis of the naturally occurring unsteadiness of the flow allows definition of the most effective frequencies for small-amplitude perturbation of the wing, which leads to substantial alterations of the aforementioned patterns of flow structure and topology adjacent to the surface.

Influence of free-stall base on tarsal joint lesions and hygiene in dairy cows.

Science.gov (United States)

Fulwider, W K; Grandin, T; Garrick, D J; Engle, T E; Lamm, W D; Dalsted, N L; Rollin, B E

2007-07-01

The objective was to quantify the incidence of tarsal lesions and level of hygiene by stall bed type. Cows were scored on 100 dairies from Wisconsin, Minnesota, Indiana, Iowa, and New York in the fall and winter. Thirty-eight dairies used rubber-filled mattresses (RFM), 27 had sand beds, 29 had waterbeds, and 6 used compost packs (CPk). Stocking density, stall dimensions, bedding amount, bedding frequency, and type of bedding were recorded. One pen of early-lactation multiparous cows on each dairy was scored based on injury of the tarsal joints at the lateral and medial surfaces and tuber calcis at the dorsal, lateral, and medial surfaces. A tarsal score of 1 represented hair loss, 2 was moderate, and 3 indicated severe swelling. Differences between bed types in the percentages of cows with lesions were tested with one-way ANOVA by lesion severity and incidence, with farm as the experimental unit. Cows on sand beds or waterbeds had fewer lesion scores of 1, 2, and 3 than those on RFM. The percentages of score 1 were 54.6 +/- 4.4 (RFM), 22.5 +/- 4.7 (sand), and 29.8 +/- 4.3 (waterbed), whereas the percentages of score 2 were 14.0 +/- 1.4, 2.3 +/- 1.5, and 5.0 +/- 1.4, and of score 3 were 3.0 +/- 0.4, 0.2 +/- 0.4, and 0.4 +/- 0.4. Cows on CPk had no lesions. Hygiene scores ranged from 1 to 5, with 1 being clean and 5 soiled. The percentages of hygiene score 1 were 0 (compost), 0.4 (RFM), 0.4 (sand), and 0.4 (waterbeds); those with score 2 were 79.0, 84.0 +/- 0.01, 73.2 +/- 0.01, and 80.4 +/- 0.01; with score 3 were 20.3, 15.2 +/- 0.01, 23.8 +/- 0.01, and 18.6 +/- 0.01; with score 4 were 0.8, 0.005 +/- 0.001, 0.006 +/- 0.001, and 0.025 +/- 0.003; and with score 5 was 0 for all bed types. Cows on RFM and waterbeds had improved hygiene compared with cows on sand beds. There was no difference in somatic cell count (SCC) by bed type. The percentage of cows in fourth lactation or greater on waterbeds (19.8 +/- 1.8) was greater than those on RFM (13.3 +/- 1.6) or on sand

Custo e resultados do tratamento de seqüelas de laminite bovina: relato de 112 casos em vacas em lactação no sistema free-stall Results and costs of treatment for bovine laminitis sequelae: study of 112 lameness cases in lactating cows in free-stall system

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P.M. Ferreira

2004-10-01

Full Text Available Os resultados e o custo do tratamento de seqüelas podais da laminite subclínica são descritos em 112 casos de manqueira em vacas em lactação mantidas no sistema free-stall. As observações feitas durante um ano abrangeram animais de 2,5 a 10 anos de idade, da primeira à sexta lactação e com média de produção de 8.000±2.000kg de leite. O protocolo de tratamento, descrito detalhadamente para cada uma das afecções podais, foi eficiente na reversão de todas elas. O custo total do tratamento para o rebanho foi de US$5,005.23, equivalente ao custo médio de US$44.68 por animal. O tratamento das úlceras de sola foi o mais dispendioso (US$72.58 e o mais demorado (26,8 dias. As afecções mais comuns foram os abscessos de sola e do talão e as lesões da linha branca (64/112 ou 57,2%.The results and costs of treatments of feet sequelae of subclinic dairy cattle laminitis were described in 112 cases of lameness in lactating cows maintained in free stall system. The analyses were performed in an one-year-period using 2.5 to 10 year-old, first to sixth parity cows. Average milk yield was 8,000±2,000kg. The treatment protocol was described in details for each digit lesion and it was very successful to reverse all kinds of lesions. The total treatment cost for the herd was US$5,005.23 and the mean cost/animal was US$44.68. The ulcer treatments were costly (US$72.58 and longer (26.8 days. Sole and heel abscesses and white line disease at the foe (64/112 or 57.2% were most commonly observed.

Mms1 is an assistant for regulating G-quadruplex DNA structures.

Science.gov (United States)

Schwindt, Eike; Paeschke, Katrin

2017-11-02

The preservation of genome stability is fundamental for every cell. Genomic integrity is constantly challenged. Among those challenges are also non-canonical nucleic acid structures. In recent years, scientists became aware of the impact of G-quadruplex (G4) structures on genome stability. It has been shown that folded G4-DNA structures cause changes in the cell, such as transcriptional up/down-regulation, replication stalling, or enhanced genome instability. Multiple helicases have been identified to regulate G4 structures and by this preserve genome stability. Interestingly, although these helicases are mostly ubiquitous expressed, they show specificity for G4 regulation in certain cellular processes (e.g., DNA replication). To this date, it is not clear how this process and target specificity of helicases are achieved. Recently, Mms1, an ubiquitin ligase complex protein, was identified as a novel G4-DNA-binding protein that supports genome stability by aiding Pif1 helicase binding to these regions. In this perspective review, we discuss the question if G4-DNA interacting proteins are fundamental for helicase function and specificity at G4-DNA structures.

Evaluation of rice mutant lines for resistance to brown planthopper, nilaparvata lugens stall

International Nuclear Information System (INIS)

Mugiono

1985-01-01

The most important and common insect in rice cultivation in South East Asia is brown planthopper, nilaparvata lugens stall. Seven rice mutant lines produced by the National Atomic Energy Agency, Indonesia, were tested at IRRI, the Philippines for resistance to brown planthopper. Those mutant lines were Atomita 1, 627/10-3/PsJ, Atomita 2 and 627/4-E/PsJ originated from Pelita 1/1 which was irradiated with 0.2 kGy of gamma rays and A227/2/PsJ, A227/3/PsJ and A227/5/PsJ, originated from early maturing mutant A23/PsJ/72K from irradiated Pelita 1/1 which was irradiated with 0.1 kGy of gamma rays. Evaluation of resistance was carried out by seedling bulk screening, honeydew excretion, survival and population build up tests by using brown planthopper biotype 1, 2 and 3. Results of these tests showed that the seven tested mutant lines were resistant to biotype 1 but susceptible to biotype 2. Reaction to biotype 3 showed that six mutant lines tested were moderately resistant and only one mutant of 627/4-E/PsJ was susceptible. Reactions of the mutant lines to biotype 1, 2 and 3 were different from the resistant varieties, Mudgo or ASD-7. This indicated that mutant lines might have gene(s) for resistance which differed from those of resistant varieties. The results showed that resistance to brown planthopper is possible to be introduced in Indonesian rice varieties by means of mutations. (author)

Meningiomas with conventional MRI findings resembling intraaxial tumors: can perfusion-weighted MRI be helpful in differentiation?

International Nuclear Information System (INIS)

Hakyemez, Bahattin; Yildirim, Nalan; Erdogan, Cueneyt; Parlak, Mufit; Kocaeli, Hasan; Korfali, Ender

2006-01-01

To investigate the contribution of perfusion-weighted MRI to the differentiation of meningiomas with atypical conventional MRI findings from intraaxial tumors. We retrospectively analyzed 54 meningiomas, 12 glioblastomas and 13 solitary metastases. We detected 6 meningiomas with atypical features on conventional MRI resembling intraaxial tumors. The regional cerebral blood flow (rCBV) ratios of all tumors were calculated via perfusion-weighted MRI. The signal intensity-time curves were plotted and three different curve patterns were observed. The type 1 curve resembled normal brain parenchyma or the postenhancement part was minimally below the baseline, the type 2 curve was similar to the type 1 curve but with the postenhancement part above the baseline, and the type 3 curve had the postenhancement part below the baseline accompanied by widening of the curve. Student's t-test was used for statistical analysis. On CBV images meningiomas were hypervascular and the mean rCBV ratio was 10.58±2.00. For glioblastomas and metastatic lesions, the rCBV ratios were 5.02±1.40 and 4.68±1.54, respectively. There was a statistically significant difference in rCBV ratios between meningiomas and glioblastomas and metastases (P<0.001). Only one of the meningiomas displayed a type 2 curve while five showed a type 3 curve. Glioblastomas and metastases displayed either a type 1 or a type 2 curve. None of the meningiomas showed a type 1 curve and none of the glioblastomas or metastases showed a type 3 curve. (orig.)

Meningiomas with conventional MRI findings resembling intraaxial tumors: can perfusion-weighted MRI be helpful in differentiation?

Energy Technology Data Exchange (ETDEWEB)

Hakyemez, Bahattin [Uludag University Medical School, Department of Radiology, Bursa (Turkey); Bursa State Hospital, Department of Radiology, Bursa (Turkey); Yildirim, Nalan; Erdogan, Cueneyt; Parlak, Mufit [Uludag University Medical School, Department of Radiology, Bursa (Turkey); Kocaeli, Hasan; Korfali, Ender [Uludag University Medical School, Department of Neurosurgery, Bursa (Turkey)

2006-10-15

To investigate the contribution of perfusion-weighted MRI to the differentiation of meningiomas with atypical conventional MRI findings from intraaxial tumors. We retrospectively analyzed 54 meningiomas, 12 glioblastomas and 13 solitary metastases. We detected 6 meningiomas with atypical features on conventional MRI resembling intraaxial tumors. The regional cerebral blood flow (rCBV) ratios of all tumors were calculated via perfusion-weighted MRI. The signal intensity-time curves were plotted and three different curve patterns were observed. The type 1 curve resembled normal brain parenchyma or the postenhancement part was minimally below the baseline, the type 2 curve was similar to the type 1 curve but with the postenhancement part above the baseline, and the type 3 curve had the postenhancement part below the baseline accompanied by widening of the curve. Student's t-test was used for statistical analysis. On CBV images meningiomas were hypervascular and the mean rCBV ratio was 10.58{+-}2.00. For glioblastomas and metastatic lesions, the rCBV ratios were 5.02{+-}1.40 and 4.68{+-}1.54, respectively. There was a statistically significant difference in rCBV ratios between meningiomas and glioblastomas and metastases (P<0.001). Only one of the meningiomas displayed a type 2 curve while five showed a type 3 curve. Glioblastomas and metastases displayed either a type 1 or a type 2 curve. None of the meningiomas showed a type 1 curve and none of the glioblastomas or metastases showed a type 3 curve. (orig.)

Investigating fundamental properties of wind turbine wake structure using particle image velocimetry

Energy Technology Data Exchange (ETDEWEB)

Whale, J. [Univ. of Edinburgh, Dept. of Mechanical Engineering, Edinburgh (United Kingdom)

1997-08-01

Low Reynolds number flow visualization tests are often used for showing the flow pattern changes associated with changes in lift-coefficients at a higher Reynolds number. In wind turbine studies, analysis of measured wake structures at small scale may reveal fundamental properties of the wake which will offer wake modellers a more complete understanding of rotor flows. Measurements are presented from experiments on a model wind turbine rig conducted in a water channel. The laser-optics technique of Particle Image Velocimetry (PIV) is used to make simultaneous multi-point measurements of the wake flow behind small-scale rotors. Analysis of the PIV data shows trends in velocity and vorticity structure in the wake. Study of the flow close to the rotor plane reveals information on stalled flow and blade performance. (au)

Leprae reaction resembling rheumatologic disease as presenting feature of leprosy.

Science.gov (United States)

Baharuddin, Hazlyna; Taib, Tarita; Zain, Mollyza Mohd; Ch'ng, Shereen

2016-10-01

Leprosy is a chronic granulomatous infection caused by Mycobacterium leprae with predominant involvement of skin and nerves. We present a 70-year-old man with leprosy whose initial presentation resembled rheumatologic disease, due to leprae reaction. He presented with an 8-week history of worsening neuropathic pain in the right forearm, associated with necrotic skin lesions on his fingers that had ulcerated. Physical examination revealed two tender necrotic ulcers at the tip of the right middle finger and the dorsal aspect of the left middle finger. The patient had right wrist tenosynovitis and right elbow bursitis. Apart from raised inflammatory markers, the investigations for infection, connective tissue disease, vasculitis, thromboembolic disease and malignancy were negative. During the fourth week of hospitalization, we noticed a 2-cm hypoesthetic indurated plaque on the right inner arm. Further examination revealed thickened bilateral ulnar, radial and popliteal nerves. A slit skin smear was negative. Two skin biopsies and a biopsy of the olecranon bursa revealed granulomatous inflammation. He was diagnosed with paucibacillary leprosy with neuritis. He responded well to multidrug therapy and prednisolone; his symptoms resolved over a few weeks. This case illustrates the challenges in diagnosing a case of leprosy with atypical presentation in a non-endemic country. © 2016 Asia Pacific League of Associations for Rheumatology and John Wiley & Sons Australia, Ltd.

Neurogenesis in Aplysia californica resembles nervous system formation in vertebrates

International Nuclear Information System (INIS)

Jacob, M.H.

1984-01-01

The pattern of neurogenesis of the central nervous system of Aplysia californica was investigated by [ 3 H]thymidine autoradiography. Large numbers of animals at a series of early developmental stages were labeled with [ 3 H]thymidine for 24 or 48 hr and were subsequently sampled at specific intervals throughout the life cycle. I found that proliferative zones, consisting of columnar and placodal ectodermal cells, are established in regions of the body wall adjacent to underlying mesodermal cells. Mitosis in the proliferative zones generates a population of cells which leave the surface and migrate inward to join the nearby forming ganglia. Tracing specific [ 3 H]thymidine-labeled cells from the body wall to a particular ganglion and within the ganglion over time suggests that the final genomic replication of the neuronal precursors occurs before the cells join the ganglion while glial cell precursors and differentiating glial cells continue to divide within the ganglion for some time. Ultrastructural examination of the morphological features of the few mitosing cells observed within the Aplysia central nervous system supports this interpretation. The pattern of neurogenesis in the Aplysia central nervous system resembles the proliferation of cells in the neural tube and the migration of neural crest and ectodermal placode cells in the vertebrate nervous system but differs from the pattern described for other invertebrates

FILAMENTARY STRUCTURE OF STAR-FORMING COMPLEXES

International Nuclear Information System (INIS)

Myers, Philip C.

2009-01-01

The nearest young stellar groups are associated with 'hubs' of column density exceeding 10 22 cm -2 , according to recent observations. These hubs radiate multiple 'filaments' of parsec length, having lower column density and fewer stars. Systems with many filaments tend to have parallel filaments with similar spacing. Such 'hub-filament structure' is associated with all of the nine young stellar groups within 300 pc, forming low-mass stars. Similar properties are seen in infrared dark clouds forming more massive stars. In a new model, an initial clump in a uniform medium is compressed into a self-gravitating, modulated layer. The outer layer resembles the modulated equilibrium of Schmid-Burgk with nearly parallel filaments. The filaments converge onto the compressed clump, which collapses to form stars with high efficiency. The initial medium and condensations have densities similar to those in nearby star-forming clouds and clumps. The predicted structures resemble observed hub-filament systems in their size, shape, and column density, and in the appearance of their filaments. These results suggest that HFS associated with young stellar groups may arise from compression of clumpy gas in molecular clouds.

Nuclear security culture in comparison with nuclear safety culture. Resemblances and differences

International Nuclear Information System (INIS)

Kawata, Norio

2015-01-01

Since the terrorist attacks on the U.S. on September 11th, 2001, Nuclear Security has been focused on and treated as a global issue in the international community and it has also been discussed as a real and serious threat to nuclear power plants in the world since 'The Great East Japan Earthquake' in March, 2011. The International Atomic Energy Agency (IAEA) issued a document including Nuclear Security Recommendations (INFCIRC/225/Rev.5) (NSS 13) in the Nuclear Security Series and emphasized the necessity of fostering Nuclear Security Culture. Nuclear Security Culture has been frequently discussed at various kinds of seminars and events. Since the officials in charge of Nuclear Security are familiar with the area of Nuclear Safety, the relationships between Nuclear Safety Culture and Nuclear Security Culture have been the point in controversy. This paper clarifies relevance between Nuclear Safety and Security, considers resemblances and differences of their concepts and lessons learned for each culture from nuclear power plant accidents, and promotes deeper understanding of Nuclear Safety and Nuclear Security Culture. (author)

Flow structures in end-view plane of slender delta wing

Directory of Open Access Journals (Sweden)

Sahin Besir

2017-01-01

Full Text Available Present investigation focuses on unsteady flow structures in end-view planes at the trailing edge of delta wing, X/C=1.0, where consequences of vortex bursting and stall phenomena vary according to angles of attack over the range of 25° ≤ α ≤ 35° and yaw angles, β over the range of 0° ≤ β ≤ 20°. Basic features of counter rotating vortices in end-view planes of delta win with 70° sweep angle, Λ are examined both qualitatively and quantitatively using Rhodamine dye and the PIV system. In the light of present experiments it is seen that with increasing yaw angle, β symmetrical flow structure is disrupted continuously. Dispersed wind-ward side leading edge vortices cover a large part of flow domain, on the other hand, lee-ward side leading edge vortices cover only a small portion of flow domain.

Ancient sedimentary structures in the Mars, that resemble macroscopic morphology, spatial associations, and temporal succession in terrestrial microbialites.

Science.gov (United States)

Noffke, Nora

2015-02-01

Sandstone beds of the Mars have been interpreted as evidence of an ancient playa lake environment. On Earth, such environments have been sites of colonization by microbial mats from the early Archean to the present time. Terrestrial microbial mats in playa lake environments form microbialites known as microbially induced sedimentary structures (MISS). On Mars, three lithofacies of the Gillespie Lake Member sandstone display centimeter- to meter-scale structures similar in macroscopic morphology to terrestrial MISS that include "erosional remnants and pockets," "mat chips," "roll-ups," "desiccation cracks," and "gas domes." The microbially induced sedimentary-like structures identified in Curiosity rover mission images do not have a random distribution. Rather, they were found to be arranged in spatial associations and temporal successions that indicate they changed over time. On Earth, if such MISS occurred with this type of spatial association and temporal succession, they would be interpreted as having recorded the growth of a microbially dominated ecosystem that thrived in pools that later dried completely: erosional pockets, mat chips, and roll-ups resulted from water eroding an ancient microbial mat-covered sedimentary surface; during the course of subsequent water recess, channels would have cut deep into the microbial mats, leaving erosional remnants behind; desiccation cracks and gas domes would have occurred during a final period of subaerial exposure of the microbial mats. In this paper, the similarities of the macroscopic morphologies, spatial associations, and temporal succession of sedimentary structures on Mars to MISS preserved on Earth has led to the following hypothesis: The sedimentary structures in the Mars are ancient MISS produced by interactions between microbial mats and their environment. Proposed here is a strategy for detecting, identifying, confirming, and differentiating possible MISS during current and future Mars missions.

Tectonic resemblance of the Indian Platform, Pakistan with the Moesian Platform, Romania and strategy for exploration of hydrocarbons

International Nuclear Information System (INIS)

Memon, A.D.

1994-01-01

There is a remarkable tectonic resemblance between the indian Platform (Pakistan) and the Moesian Platform (Romania). As viewed in global tectonic perspective Moeslan and Indian Plates have played important role in Alpine Himalayan Orogeny; Moesian and Indian Platforms are extension of these respective plates. Characteristics features of both the platforms are block faulting which has effected not only the general tectonic framework but has also played important role in oil accumulation. Main producing rocks in the Moesian platform are Jurassic sandstones and cretaceous limestones while in the indian platform cretaceous sandstones are important reservoirs. The average geothermal gradient in the indian platform is 2.45 C/100m with the higher gradients in the central gas producing region. Geothermal gradients in the Moesian platform have an average value of 3 C/100m with higher gradients in the northern in the northern part. Some of the producing structures in both the platforms are remarkably similar, traps associated with normal faults are very important. Extensive exploration carried in the Moesian Platform makes it very important oil producing region of Romania. After the discovery of oil lower Sindh, serious exploration is being carried in the Indian platform. The paper deals with the similarities between these two important platforms. In the light of the studies of the Moesian platform, strategies or exploration of oil and gas in the Indian Platform are suggested. (author)

Acral peeling skin syndrome resembling epidermolysis bullosa simplex in a 10-month-old boy.

Science.gov (United States)

Kavaklieva, S; Yordanova, I; Bruckner-Tuderman, L; Has, C

2013-01-01

The acral peeling skin syndrome (APSS) is a rare autosomal recessive disorder clinically characterized by asymptomatic desquamation of the skin limited to the hands and feet and histologically by cleavage at the stratum granulosum and stratum corneum level [Kiritsi et al.: J Invest Dermatol 2010;130:1741-1746]. We report on a 10-month-old boy with a history of skin peeling limited to the hands and feet since 2 months of age. Clinical examination revealed erythematous erosions with peripheral desquamation and flaccid blisters. DNA mutation analysis detected two heterozygous TGM5 mutations: c.2T>C, p.M1T in exon 1 and c.337G>T, p.G113C in exon 3 in keeping with the diagnosis of APSS. The clinical presentation of APSS alone might be confusing and strongly resemble epidermolysis bullosa simplex making the differential diagnosis difficult.

The near wake structure and the development of vorticity behind a model horizontal axis wind turbine

Energy Technology Data Exchange (ETDEWEB)

Ebert, P.; Wood, D. [The Univ. of Newcastle, Dept. of Mechanical Engineering, Callaghan (Australia)

1997-08-01

The wake of a two bladed model HAWT operating at zero yaw angle and in a steady flow in a wind tunnel was measured using hot wire probes. By phase locked averaging and moving the probe axially and radially the full three dimensional mean flow file was determined. All measurements were within two chord lengths of the blades and at tip speed ratios giving high turbine power output, a condition approaching runaway, and a stalled condition. For all tip speed ratios the wakes were significantly three dimensional. Large velocity variations were associated with vortex structures in the wakes, and irrotational fluctuations caused by the blade bound circulation. The vorticity clearly defined the hub and tip vortices that traced helical paths downstream, with the constant tip vortex pitch inversely proportional to tip speed ratio. Close to the blades the flow was complicated, though vortex roll-up was completed within one chord length. Considerable changes in wake structure occurred with tip speed ratio. At high power output the wake showed tip and hub vortices connected by a diffuse vortex sheet of mostly radial vorticity from the blade boundary layers; blade bound circulation was almost constant. The structure approaching runaway was similar though the hub vortex was not well defined and formed a vortex sheet around the hub which lifted away and diffused. The stalled condition was more complicated, with evidence of incomplete tip and hub vortex formation. The stream-wise velocity of the tip vortex core decreased with increasing tip speed ratio, but this was never aligned with local streamlines. The core of the tip vortex was not circular but more elliptical. A phase locked averaged angular momentum analysis was undertaken, the extra terms introduced through phase locked averaging were small. (Abstract Truncated)

Acute paretic syndrome in juvenile White Leghorn chickens resembles late stages of acute inflammatory demyelinating polyneuropathies in humans

Directory of Open Access Journals (Sweden)

Preisinger Rudolf

2010-01-01

Full Text Available Abstract Background Sudden limb paresis is a common problem in White Leghorn flocks, affecting about 1% of the chicken population before achievement of sexual maturity. Previously, a similar clinical syndrome has been reported as being caused by inflammatory demyelination of peripheral nerve fibres. Here, we investigated in detail the immunopathology of this paretic syndrome and its possible resemblance to human neuropathies. Methods Neurologically affected chickens and control animals from one single flock underwent clinical and neuropathological examination. Peripheral nervous system (PNS alterations were characterised using standard morphological techniques, including nerve fibre teasing and transmission electron microscopy. Infiltrating cells were phenotyped immunohistologically and quantified by flow cytometry. The cytokine expression pattern was assessed by quantitative real-time PCR (qRT-PCR. These investigations were accomplished by MHC genotyping and a PCR screen for Marek's disease virus (MDV. Results Spontaneous paresis of White Leghorns is caused by cell-mediated, inflammatory demyelination affecting multiple cranial and spinal nerves and nerve roots with a proximodistal tapering. Clinical manifestation coincides with the employment of humoral immune mechanisms, enrolling plasma cell recruitment, deposition of myelin-bound IgG and antibody-dependent macrophageal myelin-stripping. Disease development was significantly linked to a 539 bp microsatellite in MHC locus LEI0258. An aetiological role for MDV was excluded. Conclusions The paretic phase of avian inflammatory demyelinating polyradiculoneuritis immunobiologically resembles the late-acute disease stages of human acute inflammatory demyelinating polyneuropathy, and is characterised by a Th1-to-Th2 shift.

Does My Baby Really Look Like Me? Using Tests for Resemblance between Parent and Child to Teach Topics in Categorical Data Analysis

Science.gov (United States)

Froelich, Amy G.; Nettleton, Dan

2013-01-01

In this article, we present a study to test whether neutral observers perceive a resemblance between a parent and a child. We demonstrate the general approach for two separate parent/ child pairs using survey data collected from introductory statistics students serving as neutral observers. We then present ideas for incorporating the study design…

Acral Peeling Skin Syndrome Resembling Epidermolysis Bullosa Simplex in a 10-Month-Old Boy

Directory of Open Access Journals (Sweden)

S. Kavaklieva

2013-08-01

Full Text Available The acral peeling skin syndrome (APSS is a rare autosomal recessive disorder clinically characterized by asymptomatic desquamation of the skin limited to the hands and feet and histologically by cleavage at the stratum granulosum and stratum corneum level [Kiritsi et al.: J Invest Dermatol 2010;130:1741-1746]. We report on a 10-month-old boy with a history of skin peeling limited to the hands and feet since 2 months of age. Clinical examination revealed erythematous erosions with peripheral desquamation and flaccid blisters. DNA mutation analysis detected two heterozygous TGM5 mutations: c.2T>C, p.M1T in exon 1 and c.337G>T, p.G113C in exon 3 in keeping with the diagnosis of APSS. The clinical presentation of APSS alone might be confusing and strongly resemble epidermolysis bullosa simplex making the differential diagnosis difficult.

The elastic transfer model of angular rate modulation in F1-ATPase stalling and controlled rotation experiments

Science.gov (United States)

Volkán-Kacsó, S.

2017-06-01

The recent experimental, theoretical and computational advances in the field of F1-ATPase single-molecule microscopy are briefly surveyed. The role of theory is revealed in the statistical analysis, interpretation and prediction of single-molecule experimental trajectories, and in linking them with atomistic simulations. In particular, a theoretical model of elastically coupled molecular group transfer is reviewed and a detailed method for its application in stalling and controlled rotation experiments is provided. It is shown how the model can predict, using previous experiments, the rates of ligand binding/release processes (steps) and their exponential dependence on rotor angle in these experiments. The concept of Brønsted slopes is reviewed in the context of the single-molecule experiments, and the rate versus rotor angle relations are explained using the elastic model. These experimental data are treated in terms of the effect of thermodynamic driving forces on the rates assuming that the rotor shaft is elastically coupled to stator ring subunits in which the steps occur. In the application of the group transfer model on an extended angular range processes leading up to the transfer are discussed. Implications for large-scale atomistic simulation are suggested for the treatment of torque-generating steps.

Gross margin losses due to Salmonella Dublin infection in Danish dairy cattle herds estimated by simulation modelling

DEFF Research Database (Denmark)

Nielsen, Torben Dahl; Kudahl, Anne Braad; Østergaard, S.

2013-01-01

and dynamic simulation model. The model incorporated six age groups (neonatal, pre-weaned calves, weaned calves, growing heifers, breeding heifers and cows) and five infection stages (susceptible, acutely infected, carrier, super shedder and resistant). The effects of introducing one S. Dublin infectious......Salmonella Dublin affects production and animal health in cattle herds. The objective of this study was to quantify the gross margin (GM) losses following introduction and spread of S. Dublin within dairy herds. The GM losses were estimated using an age-structured stochastic, mechanistic...... with poorer management and herd size, e.g. average annual GM losses were estimated to 49 euros per stall for the first year after infection, and to 8 euros per stall annually averaged over the 10 years after herd infection for a 200 cow stall herd with very good management. In contrast, a 200 cow stall herd...

Acetylene Resembling Effect of Ethylene on Seed Germination: Evaluating the Effect of Acetylene Released from Calcium Carbide

Directory of Open Access Journals (Sweden)

Kambiz MASHAYEKHI

2015-09-01

Full Text Available Some vegetable seeds need a very long time to germinate. In these kinds of seeds the second phase of germination is very long. As acetylene’s chemical structure is almost similar to the gaseous hormone ethylene, its’ physiological effect on seed germination should be very similar as well. Therefore, an experiment was established in order to enhance seed germination, by treating seeds with acetylene released from interaction of calcium carbide (CaC2 with water (H2O. A simple system was designed for efficient and proper use of gaseous acetylene resulted from the two substrates interaction, which conducted the produced gas obtained inside the interaction chamber into a sealed container wherein seeds were floating in water. This experiment aimed to evaluate the effect of one concentration of acetylene with different exposure periods (between 1 to 8 hours on parsley, celery and Swees chard seeds’ germination (chosen as late germinating vegetables. The effect of acetylene on seed germination speed and percent was investigated. There were significant differences in both percent and speed of germination within the various treatments. By floating for 3, 5 and 3 hours for parsley, celery and Swiss chard respectively, the highest germination rates were observed. The highest germination speed was achieved by 5, 5 and 3 hours floating respectively for parsley, celery and Swiss chard. Based on the results obtained, the current experiment suggests that acetylene has positive effect on enhancing seed germination of named vegetables, and played the role of ethylene, its effects resembling in regard to seed germination process.

Wind farm models and control strategies

Energy Technology Data Exchange (ETDEWEB)

Soerensen, Poul; Hansen, Anca D.; Iov, F.; Blaabjerg, F.; Donovan, M.H.

2005-08-01

This report describes models and control strategies for 3 different concepts of wind farms. Initially, the potential in improvement of grid integration, structural loads and energy production is investigated in a survey of opportunities. Then simulation models are described, including wind turbine models for a fixed speed wind turbine with active stall control and a variable speed wind turbine with doubly-fed induction generator. After that, the 3 wind farm concepts and control strategies are described. The 3 concepts are AC connected doubly fed turbines, AC connected active stall turbines and DC connected active stall turbines. Finally, some simulation examples and conclusions are presented. (au)

Structure of Ga2O3(ZnO)6: a member of the homologous series Ga2O3(ZnO)m

International Nuclear Information System (INIS)

Michiue, Yuichi; Kanke, Yasushi; Kimizuka, Noboru

2008-01-01

The structure of Ga 2 O 3 (ZnO) 6 was determined using singlecrystal X-ray diffraction techniques in the space group Cmcm. The metal ion sublattice resembles some of the Zn ions in the wurtzite ZnO structure. The oxygen ion sublattice in Ga 2 O 3 (ZnO) 6 also resembles some of the O ions in ZnO. Structural relationships between Ga 2 O 3 (ZnO) 6 and ZnO are discussed, illustrating the process for obtaining the centrosymmetric Ga 2 O 3 (ZnO) 6 structure from the noncentrosymmetric ZnO. Structures of phases in the homologous series Ga 2 O 3 (ZnO) m are predicted on the basis of the structural data for Ga 2 O 3 (ZnO) 6 . The structures of even m are constructed by simply extending the structure units seen in Ga 2 O 3 (ZnO) 6 , while those of odd m consist of structure units which are of different types from those used for even m. (orig.)

Why poverty remains high: the role of income growth, economic inequality, and changes in family structure, 1949-1999.

Science.gov (United States)

Iceland, John

2003-08-01

After dramatic declines in poverty from 1950 to the early 1970s in the United States, progress stalled. This article examines the association between trends in poverty and income growth, economic inequality, and changes in family structure using three measures of poverty: an absolute measure, a relative measure, and a quasi-relative one. I found that income growth explains most of the trend in absolute poverty, while inequality generally plays the most significant role in explaining trends in relative poverty. Rising inequality in the 1970s and 1980s was especially important in explaining increases in poverty among Hispanics, whereas changes in family structure played a significant role for children and African Americans through 1990. Notably, changes in family structure no longer had a significant association with trends in poverty for any group in the 1990s.

White Feces Syndrome of Shrimp Arises from Transformation, Sloughing and Aggregation of Hepatopancreatic Microvilli into Vermiform Bodies Superficially Resembling Gregarines

Science.gov (United States)

Sriurairatana, Siriporn; Boonyawiwat, Visanu; Gangnonngiw, Warachin; Laosutthipong, Chaowanee; Hiranchan, Jindanan; Flegel, Timothy W.

2014-01-01

Accompanying acute hepatopancreatic necrosis disease (AHPND) in cultivated Asian shrimp has been an increasing prevalence of vermiform, gregarine-like bodies within the shrimp hepatopancreas (HP) and midgut. In high quantity they result in white fecal strings and a phenomenon called white feces syndrome (WFS). Light microscopy (LM) of squash mounts and stained smears from fresh HP tissue revealed that the vermiform bodies are almost transparent with widths and diameters proportional to the HP tubule lumens in which they occur. Despite vermiform appearance, they show no cellular structure. At high magnification (LM with 40-100x objectives), they appear to consist of a thin, outer membrane enclosing a complex of thicker, inter-folded membranes. Transmission electron microscopy (TEM) revealed that the outer non-laminar membrane of the vermiform bodies bore no resemblance to a plasma membrane or to the outer layer of any known gregarine, other protozoan or metazoan. Sub-cellular organelles such as mitochondria, nuclei, endoplasmic reticulum and ribosomes were absent. The internal membranes had a tubular sub-structure and occasionally enclosed whole B-cells, sloughed from the HP tubule epithelium. These internal membranes were shown to arise from transformed microvilli that peeled away from HP tubule epithelial cells and then aggregated in the tubule lumen. Stripped of microvilli, the originating cells underwent lysis. By contrast, B-cells remained intact or were sloughed independently and whole from the tubule epithelium. When sometimes engulfed by the aggregated, transformed microvilli (ATM) they could be misinterpreted as cyst-like structures by light microscopy, contributing to gregarine-like appearance. The cause of ATM is currently unknown, but formation by loss of microvilli and subsequent cell lysis indicate that their formation is a pathological process. If sufficiently severe, they may retard shrimp growth and may predispose shrimp to opportunistic pathogens

Lynch Syndrome Associated Colon Adenocarcinoma Resembling Lymphoma on Fluoro-Deoxyglucose-Positron Emission Tomography/Computed Tomography

International Nuclear Information System (INIS)

Aparici, Carina Mari; Win, Aung Zaw

2015-01-01

The patient was a 46-year-old Asian male diagnosed with lynch syndrome associated colon adenocarcinoma in the right ascending colon. A presurgical staging 18-fluoro-deoxyglucose-positron emission tomography/computed tomography (FDG-PET/CT) found increased metabolic activity in the cervical, axillary, mediastinal, supraclavicular, para-aortic and mesenteric lymph nodes. This pattern of metastasis was very unusual for lynch syndrome associated colon adenocarcinoma and the involvement of those lymph nodes resembles the pattern of spread of lymphoma. He underwent right hemicolectomy and he was subsequently treated with 12 cycles of folinic acid (leucovorin), fluorouracil (5-FU), irinotecan. A restaging FDG-PET/CT at the end of the chemotherapy showed interval decrease in size and metabolic activity in the affected lymph nodes. FDG-PET/CT is a useful imaging modality in following-up the treatment response in colon adenocarcinoma

Capturing Structural Heterogeneity in Chromatin Fibers.

Science.gov (United States)

Ekundayo, Babatunde; Richmond, Timothy J; Schalch, Thomas

2017-10-13

Chromatin fiber organization is implicated in processes such as transcription, DNA repair and chromosome segregation, but how nucleosomes interact to form higher-order structure remains poorly understood. We solved two crystal structures of tetranucleosomes with approximately 11-bp DNA linker length at 5.8 and 6.7 Å resolution. Minimal intramolecular nucleosome-nucleosome interactions result in a fiber model resembling a flat ribbon that is compatible with a two-start helical architecture, and that exposes histone and DNA surfaces to the environment. The differences in the two structures combined with electron microscopy reveal heterogeneous structural states, and we used site-specific chemical crosslinking to assess the diversity of nucleosome-nucleosome interactions through identification of structure-sensitive crosslink sites that provide a means to characterize fibers in solution. The chromatin fiber architectures observed here provide a basis for understanding heterogeneous chromatin higher-order structures as they occur in a genomic context. Copyright © 2017 Elsevier Ltd. All rights reserved.

Revision 2 of the NPP Krsko Decommissioning Program Is Stalled

International Nuclear Information System (INIS)

Levanat, I.; Lokner, V.; Rapic, A.; Zeleznik, N.; Kralj, M.

2012-01-01

Revision 2 of the joint Slovenian-Croatian Program of NPP Krsko Decommissioning and SF andLILW Disposal was scheduled to be finished and formally approved by the end of 2009, in accordance with the bilateral Agreement on the NPP. Slightly behind the schedule, the Project team completed the entire document during spring of 2010, and in June 2010 drafted a proposal for a peer review of the Program by a dedicated IAEA expert mission. This procedure was agreed upon at the last session (May 2010) of the Intergovernmental Commission for implementation of the Agreement, when the Commission was acquainted with the five scenarios of the Revision 2 and with the estimates of their costs/financing. It was expected that the peer review would be performed soon, and that formal adoption of the Revision 2 would follow. Although in this process of approval some decisions remained to be made by the stakeholders, the Project team did select and recommend one scenario to be used for costing purposes, in order to ensure that most necessary corrections in Program financing would be timely adopted. However, the planned IAEA review was cancelled by the Advisory board, the body nominated by the Commission ''to supervise the activities and resolve the issues raised by the Project team''. By this cancellation, the process of Program revision was effectively stalled, because the Advisory board could not clearly define further course of action: differing views between the Slovenian and the Croatian part of the Advisory board appeared, in particular regarding the set of Program scenarios and regarding the appropriateness of the Revision 2 document for the IAEA review; nonetheless, the Advisory board sent to the Project team a compilation of requests to modify Revision 2 document. The Project team determined that some minor requests were easy to fulfill, but other modifications could only be carried out after changes in the boundary conditions (approved by the Commission), or changes in national

Internal structure changes of eyelash induced by eye makeup.

Science.gov (United States)

Fukami, Ken-Ichi; Inoue, Takafumi; Kawai, Tomomitsu; Takeuchi, Akihisa; Uesugi, Kentaro; Suzuki, Yoshio

2014-01-01

To investigate how eye makeup affects eyelash structure, internal structure of eyelashes were observed with a scanning X-ray microscopic tomography system using synchrotron radiation light source. Eyelash samples were obtained from 36 Japanese women aged 20-70 years and whose use of eye makeup differed. Reconstructed cross-sectional images showed that the structure of the eyelash closely resembled that of scalp hair. The eyelash structure is changed by use of eye makeup. There was a positive correlation between the frequency of mascara use and the degree of cracking in cuticle. The positive correlation was also found between the frequency of mascara use and the porosity of the cortex. By contrast, the use of eyelash curler did not affect the eyelash structure with statistical significance.

Structures of SAS-6 suggest its organization in centrioles.

Science.gov (United States)

van Breugel, Mark; Hirono, Masafumi; Andreeva, Antonina; Yanagisawa, Haru-aki; Yamaguchi, Shoko; Nakazawa, Yuki; Morgner, Nina; Petrovich, Miriana; Ebong, Ima-Obong; Robinson, Carol V; Johnson, Christopher M; Veprintsev, Dmitry; Zuber, Benoît

2011-03-04

Centrioles are cylindrical, ninefold symmetrical structures with peripheral triplet microtubules strictly required to template cilia and flagella. The highly conserved protein SAS-6 constitutes the center of the cartwheel assembly that scaffolds centrioles early in their biogenesis. We determined the x-ray structure of the amino-terminal domain of SAS-6 from zebrafish, and we show that recombinant SAS-6 self-associates in vitro into assemblies that resemble cartwheel centers. Point mutations are consistent with the notion that centriole formation in vivo depends on the interactions that define the self-assemblies observed here. Thus, these interactions are probably essential to the structural organization of cartwheel centers.

High-fidelity simulations of moving and flexible airfoils at low Reynolds numbers

Energy Technology Data Exchange (ETDEWEB)

Visbal, Miguel R.; Gordnier, Raymond E.; Galbraith, Marshall C. [Air Force Research Laboratory, Computational Sciences Branch, Air Vehicles Directorate, Wright-Patterson AFB, OH (United States)

2009-05-15

The present paper highlights results derived from the application of a high-fidelity simulation technique to the analysis of low-Reynolds-number transitional flows over moving and flexible canonical configurations motivated by small natural and man-made flyers. This effort addresses three separate fluid dynamic phenomena relevant to small fliers, including: laminar separation and transition over a stationary airfoil, transition effects on the dynamic stall vortex generated by a plunging airfoil, and the effect of flexibility on the flow structure above a membrane airfoil. The specific cases were also selected to permit comparison with available experimental measurements. First, the process of transition on a stationary SD7003 airfoil section over a range of Reynolds numbers and angles of attack is considered. Prior to stall, the flow exhibits a separated shear layer which rolls up into spanwise vortices. These vortices subsequently undergo spanwise instabilities, and ultimately breakdown into fine-scale turbulent structures as the boundary layer reattaches to the airfoil surface. In a time-averaged sense, the flow displays a closed laminar separation bubble which moves upstream and contracts in size with increasing angle of attack for a fixed Reynolds number. For a fixed angle of attack, as the Reynolds number decreases, the laminar separation bubble grows in vertical extent producing a significant increase in drag. For the lowest Reynolds number considered (Re{sub c} = 10 {sup 4}), transition does not occur over the airfoil at moderate angles of attack prior to stall. Next, the impact of a prescribed high-frequency small-amplitude plunging motion on the transitional flow over the SD7003 airfoil is investigated. The motion-induced high angle of attack results in unsteady separation in the leading edge and in the formation of dynamic-stall-like vortices which convect downstream close to the airfoil. At the lowest value of Reynolds number (Re{sub c}=10 {sup 4

Studies on the power output of a MADEAE-30 operating on complex terrain. Annual Energy Production estimation and Multivariable analysis. A case of multi-stall effect

International Nuclear Information System (INIS)

Cuerva, A.

1996-01-01

The main need of the EWTS-II Sub-project IV group is to have a suitable data-base which allows it to reach proper conclusions on the characteristics of power performance of wind turbines in complex terrain. With this aim, this document presents an analysis on the power output of the MADE AE-30 Wind turbine operating at Tarifa (also data from flat terrain are enclosed as a reference). An application of the bin method and AEP estimation for energy production method. In the two last issues a directional analysis and an study for two different turbulence intensity ranges are enclosed. Finally the STEPWISE multirregression method is applied on the measurements to identify the stored parameters that have influence on the power output. A brief description of multi stall effect is enclosed. (Author) 7 refs

Parent–offspring resemblance in colony-specific adult survival of cliff swallows

Science.gov (United States)

Brown, Charles R.; Roche, Erin A.; Brown, Mary Bomberger

2015-01-01

Survival is a key component of fitness. Species that occupy discrete breeding colonies with different characteristics are often exposed to varying costs and benefits associated with group size or environmental conditions, and survival is an integrative net measure of these effects. We investigated the extent to which survival probability of adult (≥1-year old) cliff swallows (Petrochelidon pyrrhonota) occupying different colonies resembled that of their parental cohort and thus whether the natal colony had long-term effects on individuals. Individuals were cross-fostered between colonies soon after hatching and their presence as breeders monitored at colonies in the western Nebraska study area for the subsequent decade. Colony-specific adult survival probabilities of offspring born and reared in the same colony, and those cross-fostered away from their natal colony soon after birth, were positively and significantly related to subsequent adult survival of the parental cohort from the natal colony. This result held when controlling for the effect of natal colony size and the age composition of the parental cohort. In contrast, colony-specific adult survival of offspring cross-fostered to a site was unrelated to that of their foster parent cohort or to the cohort of non-fostered offspring with whom they were reared. Adult survival at a colony varied inversely with fecundity, as measured by mean brood size, providing evidence for a survival–fecundity trade-off in this species. The results suggest some heritable variation in adult survival, likely maintained by negative correlations between fitness components. The study provides additional evidence that colonies represent non-random collections of individuals.

Multi-atlas pancreas segmentation: Atlas selection based on vessel structure.

Science.gov (United States)

Karasawa, Ken'ichi; Oda, Masahiro; Kitasaka, Takayuki; Misawa, Kazunari; Fujiwara, Michitaka; Chu, Chengwen; Zheng, Guoyan; Rueckert, Daniel; Mori, Kensaku

2017-07-01

Automated organ segmentation from medical images is an indispensable component for clinical applications such as computer-aided diagnosis (CAD) and computer-assisted surgery (CAS). We utilize a multi-atlas segmentation scheme, which has recently been used in different approaches in the literature to achieve more accurate and robust segmentation of anatomical structures in computed tomography (CT) volume data. Among abdominal organs, the pancreas has large inter-patient variability in its position, size and shape. Moreover, the CT intensity of the pancreas closely resembles adjacent tissues, rendering its segmentation a challenging task. Due to this, conventional intensity-based atlas selection for pancreas segmentation often fails to select atlases that are similar in pancreas position and shape to those of the unlabeled target volume. In this paper, we propose a new atlas selection strategy based on vessel structure around the pancreatic tissue and demonstrate its application to a multi-atlas pancreas segmentation. Our method utilizes vessel structure around the pancreas to select atlases with high pancreatic resemblance to the unlabeled volume. Also, we investigate two types of applications of the vessel structure information to the atlas selection. Our segmentations were evaluated on 150 abdominal contrast-enhanced CT volumes. The experimental results showed that our approach can segment the pancreas with an average Jaccard index of 66.3% and an average Dice overlap coefficient of 78.5%. Copyright © 2017 Elsevier B.V. All rights reserved.

Pulmonary Extramedullary Hematopoiesis in a Patient with Chronic Asthma Resembling Lung Cancer: A Case Report

Directory of Open Access Journals (Sweden)

Massood Hosseinzadeh

2012-01-01

Full Text Available Background. Extramedullary hematopoiesis is most often seen in reticuloendothelial organs specially spleen, liver, or lymph nodes, and it is rarely seen in lung parenchyma. Almost all reported cases of pulmonary extramedullary hematopoiesis occurred following myeloproliferative disorders specially myelofibrosis. Other less common underlying causes are thalassemia syndromes and other hemoglobinopathies. There was not any reported case of pulmonary extramedullary hematopoiesis in asthmatic patients in the medical literature. Case. Here we reported a 65-year-old lady who was a known case of bronchial asthma with recent developed right lower lobe lung mass. Chest X-ray and CT studies showed an infiltrating mass resembling malignancy. Fine needle aspiration cytology of mass revealed pulmonary extramedullary hematopoiesis. The patient followed for 10 months with serial physical examination and laboratory evaluations which were unremarkable. Conclusion. Extramedullary hematopoiesis of lung parenchyma can be mistaken for lung cancer radiologically. Although previous reported cases occurred with myelofibrosis or hemoglobinopathies, we are reporting the first case of asthma-associated extramedullary hematopoiesis.

Dna2 nuclease-helicase structure, mechanism and regulation by Rpa.

Science.gov (United States)

Zhou, Chun; Pourmal, Sergei; Pavletich, Nikola P

2015-11-02

The Dna2 nuclease-helicase maintains genomic integrity by processing DNA double-strand breaks, Okazaki fragments and stalled replication forks. Dna2 requires ssDNA ends, and is dependent on the ssDNA-binding protein Rpa, which controls cleavage polarity. Here we present the 2.3 Å structure of intact mouse Dna2 bound to a 15-nucleotide ssDNA. The nuclease active site is embedded in a long, narrow tunnel through which the DNA has to thread. The helicase domain is required for DNA binding but not threading. We also present the structure of a flexibly-tethered Dna2-Rpa interaction that recruits Dna2 to Rpa-coated DNA. We establish that a second Dna2-Rpa interaction is mutually exclusive with Rpa-DNA interactions and mediates the displacement of Rpa from ssDNA. This interaction occurs at the nuclease tunnel entrance and the 5' end of the Rpa-DNA complex. Hence, it only displaces Rpa from the 5' but not 3' end, explaining how Rpa regulates cleavage polarity.

A novel and automatic mammographic texture resemblance marker is an independent risk factor for breast cancer

DEFF Research Database (Denmark)

Nielsen, Mads; Karemore, Gopal; Loog, Marco

2011-01-01

Objective: We investigated whether breast cancer is predicted by a breast cancer risk mammographic texture resemblance (MTR) marker. Methods: A previously published case-control study included 495 women of which 245 were diagnosed with breast cancer. In baseline mammograms, 2-4 years prior...... to diagnosis, the following mammographic parameters were analysed for relation to breast cancer risk: (C) categorical parenchymal pattern scores; (R) radiologist's percentage density, (P) computer-based percentage density; (H) computer-based breast cancer risk MTR marker; (E) computer-based hormone replacement...... treatment MTR marker; and (A) an aggregate of P and H. Results: Density scores, C, R, and P correlated (tau=0.3-0.6); no other pair of scores showed large (tau>0.2) correlation. For the parameters, the odds ratios of future incidence of breast cancer comparing highest to lowest categories (146 and 106...

The Pattern of Sexual Interest of Female-to-Male Transsexual Persons With Gender Identity Disorder Does Not Resemble That of Biological Men: An Eye-Tracking Study

Directory of Open Access Journals (Sweden)

Akira Tsujimura

2017-09-01

Tsujimura A, Kiuchi H, Soda T, et al. The Pattern of Sexual Interest of Female-to-Male Transsexual Persons With Gender Identity Disorder Does Not Resemble That of Biological Men: An Eye-Tracking Study. Sex Med 2017;5:e169–e174.

Adult family members and their resemblance of coronary heart disease risk factors: The Cardiovascular Disease Study in Finnmark

International Nuclear Information System (INIS)

Brenn, Tormod

1997-01-01

Coronary heart disease tends to run in families, and the familial resemblance of major risk factors for the disease was examined among various types of adult family members. Family units were assembled from a total of 4,738 men and women who took part in a cross sectional health survey in four Norwegian municipalities where all inhabitants between 20 and 52 years of age were invited. After adjusting for age and other confounders, correlation coefficients were derived as a measure of the degree of resemblance. Viewed across all types of investigated familial relationships, similarity was found to be stronger for total cholesterol than for high-density lipoprotein cholesterol and triglycerides, and also stronger for systolic than for diastolic blood pressure. Between husbands and wives (3,060 subjects), correlations were small (between 0.02 and 0.06), except for 0.11 for total cholesterol. Lipid and blood pressure correlations ranged from 0.13 to 0.27 for parents and their offspring (471 subjects, p < 0.05) and from 0.11 to 0.22 among siblings (2,166 subjects, p < 0.01). Sibling correlations were consistent across age groups. Furthermore, reports from each individual on daily smoking (yes or no) revealed that husbands and wives had similar habits in 63.5% of all marriages as compared with the expected 49.4% had no smoking similarity at all been present. Smoking concordance was also demonstrated among siblings (p < 0.01). The persistent pattern of lipid and blood pressure aggregation among genetically related individuals from 20 to 52 years of age and the much weaker such similarity between husbands and wives, point towards genes or commonly shared environment at early ages as a major reason why coronary heart disease runs in families

The Impact of Stereoscopic Imagery and Motion on Anatomical Structure Recognition and Visual Attention Performance

Science.gov (United States)

Remmele, Martin; Schmidt, Elena; Lingenfelder, Melissa; Martens, Andreas

2018-01-01

Gross anatomy is located in a three-dimensional space. Visualizing aspects of structures in gross anatomy education should aim to provide information that best resembles their original spatial proportions. Stereoscopic three-dimensional imagery might offer possibilities to implement this aim, though some research has revealed potential impairments…

Fine structure and immunocytochemistry of a new chemosensory system in the Chiton larva (Mollusca: Polyplacophora)

DEFF Research Database (Denmark)

Haszprunar, Gerhard; Friedrich, Stefan; Wanninger, Andreas

2002-01-01

symmetrically situated pairs lying dorsolaterally and ventrolaterally in the pretrochal part of the trochophore-like larva and they send axons into the cerebral commissure. They are lost at metamorphosis. The fine structure of these cells strongly resembles that of so-called "ampullary cells" known from various...

Exploring farmers’ seasonal and full year adoption of stall feeding of livestock in Tigrai region, Ethiopia

Directory of Open Access Journals (Sweden)

Hadush Muuz

2017-01-01

Full Text Available Adoption of stall feeding (SF of livestock was assessed in northern Ethiopia based on a household survey conducted in 2015. The study covered 21 communities in Tigrai to account for differences in agroecology. The purpose of this study was to understand the driving factors of full or seasonal SF adoption and its intensity. A Heckman selection model was used to estimate adoption and extent of adoption based on a model of technology adoption within an agricultural household framework, and Poisson Model for explaining the number of SF adopting seasons. The descriptive results indicate that 36% of the farmers were actually practicing SF in a full year whereas 55.6% were seasonal adopters in the study area. Empirical results of this study showed that our result is in favor of the Boserupian hypothesis indicating that small grazing land and large exclosure are associated with a higher probability of use of SF and with a higher number of SF adopting seasons. In a similar vein, small average village farm size stimulated SF adoption and adopting seasons, Availability of labor and a number of breed cows significantly increased the probability of using SF by 0.01% and 66% respectively. While animal shock had a marginal effect of 14%, factors such as access to information and early exposure increased SF adoption by about 18% and 6%. Similarly, the positive marginal effect of real milk price is 15%. However, SF appears to be less attractive to those farmers with more herd size and less crop residue.

The formation of ethnically mixed partnerships in Estonia: A stalling trend from a two-sided perspective

Directory of Open Access Journals (Sweden)

Leen Rahnu

2018-03-01

Full Text Available Background: Ethnically mixed partnerships are often regarded as the ultimate evidence of the integration of migrants and their descendants into their host society. A common finding in the literature is an increase in the occurrence of mixed partnerships across migrant generations. Objective: This study investigates the formation of minority-majority partnerships in Estonia, with special attention to the variation associated with the migrants' generation and their exposure to the majority population. Methods: The study uses pooled data from the Estonian Family and Fertility Survey (FFS and the Estonian Generations and Gender Survey (GGS, and estimates proportional hazards models. Results: The experience of second-generation migrants indicates a stalling trend in the incidence of mixed partnerships between the majority population and migrant groups, which is rooted in contextual features. Apart from residential proximity, the study shows the salience of early acquisition of the host society language. Our results for the majority population highlight the role of international migration, which exposes host populations to mixed partnership formation. Conclusions: The results lend support to the view that the integration of migrant populations through mixed partnering is a lengthy process that stretches across several generations. A linguistically divided school system and residential segregation contribute to the pillarization of society. Contribution: By focussing on an Eastern European context, the study contributes to a more comprehensive account of mixed unions in different socioeconomic and cultural settings. Estonia provides an interesting case as its migrant-origin minorities span several generations. The study underscores the importance of contextual factors for both the minority and majority populations.

Measuring excess free energies of self-assembled membrane structures.

Science.gov (United States)

Norizoe, Yuki; Daoulas, Kostas Ch; Müller, Marcus

2010-01-01

Using computer simulation of a solvent-free, coarse-grained model for amphiphilic membranes, we study the excess free energy of hourglass-shaped connections (i.e., stalks) between two apposed bilayer membranes. In order to calculate the free energy by simulation in the canonical ensemble, we reversibly transfer two apposed bilayers into a configuration with a stalk in three steps. First, we gradually replace the intermolecular interactions by an external, ordering field. The latter is chosen such that the structure of the non-interacting system in this field closely resembles the structure of the original, interacting system in the absence of the external field. The absence of structural changes along this path suggests that it is reversible; a fact which is confirmed by expanded-ensemble simulations. Second, the external, ordering field is changed as to transform the non-interacting system from the apposed bilayer structure to two-bilayers connected by a stalk. The final external field is chosen such that the structure of the non-interacting system resembles the structure of the stalk in the interacting system without a field. On the third branch of the transformation path, we reversibly replace the external, ordering field by non-bonded interactions. Using expanded-ensemble techniques, the free energy change along this reversible path can be obtained with an accuracy of 10(-3)k(B)T per molecule in the n VT-ensemble. Calculating the chemical potential, we obtain the free energy of a stalk in the grandcanonical ensemble, and employing semi-grandcanonical techniques, we calculate the change of the excess free energy upon altering the molecular architecture. This computational strategy can be applied to compute the free energy of self-assembled phases in lipid and copolymer systems, and the excess free energy of defects or interfaces.

The influence of engineering design considerations on species recruitment and succession on coastal defence structures

OpenAIRE

Jackson, Juliette Elizabeth

2015-01-01

Engineering design considerations of artificial coastal structures were tested to resemble as far as possible the nearest natural equivalent habitat, ecologically valuable rocky shores, as a potential management option. Coastal areas around the world attract urbanisation but these transitional areas between sea and land are inherently vulnerable to risk of flooding and erosion. Thus hard structures are often built in sensitive coastal environments to defend assets such as property and infrast...

Natural ventilation for free stall dairy barns

OpenAIRE

Gay, Susan Wood

2009-01-01

Natural ventilation is a result of a combination good construction, correct temperature, humidity control, air exchange. This publication discusses how to achieve natural ventilation in your structure.

Using nature-based rehabilitation to restart a stalled process of rehabilitation in individuals with stress-related mental illness.

Science.gov (United States)

Sahlin, Eva; Ahlborg, Gunnar; Tenenbaum, Artur; Grahn, Patrik

2015-02-09

After a period of decrease, sick leave in Sweden due to psychiatric diagnoses is on the increase. The lack of established rehabilitation programmes for patients with stress-related mental disorders (SRMD) has opened up for the use of garden/nature in a multimodal rehabilitation context (Nature-Based Rehabilitation, NBR). Region Västra Götaland (VGR) started an NBR to offer additional rehabilitation for its employees on long-term sick leave due to SRMD, where initial care had not been sufficient. The aim was to explore whether the mental health and well-being of NBR participants had improved at the end of the NBR and at three follow-ups, and to explore the development of sick leave and health care utilization according to the NBR model (n = 57) and an occupational health service (OHS) model (n = 45). Self-assessment instruments for measuring burnout, depression, anxiety and wellbeing, and data from regional and national registers were used. Results showed decreased scores on burnout, depression and anxiety, and increased well-being scores and significantly reduced health care utilization in the NBR group. A large movement from ordinary sickness benefit to rehabilitation benefit was observed, which was not observed in the OHS group. The two groups were in different rehabilitation phases, which limited comparisons. The results point to beneficial effects of using NBR for this patient group and for enhancing a stalled rehabilitation process.

Structural systematics of rare earth complexes. III. Structural characterization of lanthanoid (III) picrate hydrates: gadolinium picrate dodecahydrate - an x-ray-induced phase modifications? - and some general aspects of structural chemistry of lanthanoid picrates

International Nuclear Information System (INIS)

Harrowfield, J.M.; Weimin, Lu; Brian, W.S.; White, A.H.

1994-01-01

In the course of the previous studies (Parts I and II), an unusual result was observed in the case of the structure determination of hydrated gadolinium(III) picrate. Midway through data collection, the monoclinic P2 1 /c phase modification (X-ray-induced?) to a similar cell more nearly resembling that of the La→Pr structure type recorded previously, with no loss of crystal integrity, and with useful data sets being obtained on both forms. Redetermination of the structure with a fresh sample yielded no reproduction of the anomaly. These results are recorded and discussed, together with an overview of the consequences of the data of Parts I-III in relation to those of other literature in the field. 13 refs., 4 tabs., 1 fig

Studies on the power output of a MADE AE-30 operating on complex terrain. Annual Energy Production estimation and Multivariable analysis. A case of multi-stall effect

Energy Technology Data Exchange (ETDEWEB)

Cuerva, A.

1996-12-01

The main need of the EWTS-II Sub-project IV group is to have a suitable data-base which allows it to reach proper conclusions on the characteristics of power performance of wind turbines in complex terrain. With this aim, this document presents an analysis on the power output of the MADE AE-30 Wind turbine operating at Tarifa (also data from flat terrain are enclosed as a reference). An application of the bin method and AEP estimation for energy production method, in the two last issues a directional analysis and an study for two different turbulence intensity ranges are enclosed. Finally the Stepwise multirregression method is applied on the measurements to identify the stored parameters that have influence on the power output. A brief description of multi stall effect is enclosed. (Author)

Young Children's Reasoning About Physical & Behavioural Family Resemblance: Is There a Place for a Precursor Model of Inheritance?

Science.gov (United States)

Ergazaki, Marida; Alexaki, Aspa; Papadopoulou, Chrysa; Kalpakiori, Marieleni

2014-02-01

This paper aims at exploring (a) whether preschoolers recognize that offspring share physical traits with their parents due to birth and behavioural ones due to nurture, and (b) whether they seem ready to explain shared physical traits with a `pre-biological' causal model that includes the contribution of both parents and a rudimentary notion of genes. This exploration is supposed to provide evidence for our next step, which is the development of an early years' learning environment about inheritance. Conducting individual, semi-structured interviews with 90 preschoolers (age 4.5-5.5) of four public kindergartens in Patras, we attempted to trace their reasoning about (a) whether and why offspring share physical and behavioural traits with parents and (b) which mechanism could better explain the shared physical traits. The probes were a modified six-case version of Solomon et al. (Child Dev 67:151-171, 1996) `adoption task, as well as a three-case task based on Springer's (Child Dev 66:547-558, 1995) `mechanism task' and on Solomon and Johnson's (Br J Dev Psychol 18(1):81-96, 2000) idea of genes as a `conceptual placeholder'. The qualitative and quantitative analysis of the interviews showed overlapping reasoning about the origin of physical and behavioural family resemblance. Nevertheless, we did trace the `birth-driven' argument for the attribution of the offspring's physical traits to the biological parents, as well as a preference for the `pre-biological' model that introduces a rudimentary idea of genes in order to explain shared physical traits between parents and offspring. The findings of the study and the educational implications are thoroughly discussed.

Delineating the structure of normal and abnormal personality: an integrative hierarchical approach.

Science.gov (United States)

Markon, Kristian E; Krueger, Robert F; Watson, David

2005-01-01

Increasing evidence indicates that normal and abnormal personality can be treated within a single structural framework. However, identification of a single integrated structure of normal and abnormal personality has remained elusive. Here, a constructive replication approach was used to delineate an integrative hierarchical account of the structure of normal and abnormal personality. This hierarchical structure, which integrates many Big Trait models proposed in the literature, replicated across a meta-analysis as well as an empirical study, and across samples of participants as well as measures. The proposed structure resembles previously suggested accounts of personality hierarchy and provides insight into the nature of personality hierarchy more generally. Potential directions for future research on personality and psychopathology are discussed.

Delineating the Structure of Normal and Abnormal Personality: An Integrative Hierarchical Approach

Science.gov (United States)

Markon, Kristian E.; Krueger, Robert F.; Watson, David

2008-01-01

Increasing evidence indicates that normal and abnormal personality can be treated within a single structural framework. However, identification of a single integrated structure of normal and abnormal personality has remained elusive. Here, a constructive replication approach was used to delineate an integrative hierarchical account of the structure of normal and abnormal personality. This hierarchical structure, which integrates many Big Trait models proposed in the literature, replicated across a meta-analysis as well as an empirical study, and across samples of participants as well as measures. The proposed structure resembles previously suggested accounts of personality hierarchy and provides insight into the nature of personality hierarchy more generally. Potential directions for future research on personality and psychopathology are discussed. PMID:15631580

Spectral Barcoding of Quantum Dots: Deciphering Structural Motifs from the Excitonic Spectra

International Nuclear Information System (INIS)

Mlinar, V.; Zunger, A.

2009-01-01

Self-assembled semiconductor quantum dots (QDs) show in high-resolution single-dot spectra a multitude of sharp lines, resembling a barcode, due to various neutral and charged exciton complexes. Here we propose the 'spectral barcoding' method that deciphers structural motifs of dots by using such barcode as input to an artificial-intelligence learning system. Thus, we invert the common practice of deducing spectra from structure by deducing structure from spectra. This approach (i) lays the foundation for building a much needed structure-spectra understanding for large nanostructures and (ii) can guide future design of desired optical features of QDs by controlling during growth only those structural motifs that decide given optical features.

Edge-functionalization of armchair graphene nanoribbons with pentagonal-hexagonal edge structures.

Science.gov (United States)

Ryou, Junga; Park, Jinwoo; Kim, Gunn; Hong, Suklyun

2017-06-21

Using density functional theory calculations, we have studied the edge-functionalization of armchair graphene nanoribbons (AGNRs) with pentagonal-hexagonal edge structures. While the AGNRs with pentagonal-hexagonal edge structures (labeled (5,6)-AGNRs) are metallic, the edge-functionalized (5,6)-AGNRs with substitutional atoms opens a band gap. We find that the band structures of edge-functionalized (5,6)-N-AGNRs by substitution resemble those of defect-free (N-1)-AGNR at the Γ point, whereas those at the X point show the original ones of the defect-free N-AGNR. The overall electronic structures of edge-functionalized (5,6)-AGNRs depend on the number of electrons, supplied by substitutional atoms, at the edges of functionalized (5,6)-AGNRs.

Alloxan-Induced Diabetes Causes Morphological and Ultrastructural Changes in Rat Liver that Resemble the Natural History of Chronic Fatty Liver Disease in Humans

Directory of Open Access Journals (Sweden)

Amanda Natália Lucchesi

2015-01-01

Full Text Available Purpose. This study evaluated the long-term effects of alloxan-induced diabetes in rat liver. Methods. Thirty nondiabetic control rats (NC and 30 untreated diabetic (UD rats were divided into three subgroups sacrificed after 6, 14, or 26 weeks. Clinical and laboratory parameters were assessed. Fresh liver weight and its relationship with body weight were obtained, and liver tissue was analyzed. Results. UD rats showed sustained hyperglycemia, high glycosylated hemoglobin, and low plasma insulin. High serum levels of AST and ALT were observed in UD rats after 2 weeks, but only ALT remained elevated throughout the experiment. Fresh liver weight was equal between NC and UD rats, but the fresh liver weight/body weight ratio was significantly higher in UD rats after 14 and 26 weeks. UD rats showed liver morphological changes characterized by hepatic sinusoidal enlargement and micro- and macrovesicular hepatocyte fatty degeneration with progressive liver structure loss, steatohepatitis, and periportal fibrosis. Ultrastructural changes of hepatocytes, such as a decrease in the number of intracytoplasmic organelles and degeneration of mitochondria, rough endoplasmic reticulum, and nuclei, were also observed. Conclusion. Alloxan-induced diabetes triggered liver morphological and ultrastructural changes that closely resembled human disease, ranging from steatosis to steatohepatitis and liver fibrosis.

LONGITUDINAL STRUCTURAL CHANGES IN LATE-ONSET RETINAL DEGENERATION.

Science.gov (United States)

Cukras, Catherine; Flamendorf, Jason; Wong, Wai T; Ayyagari, Radha; Cunningham, Denise; Sieving, Paul A

2016-12-01

To characterize longitudinal structural changes in early stages of late-onset retinal degeneration to investigate pathogenic mechanisms. Two affected siblings, both with a S163R missense mutation in the causative gene C1QTNF5, were followed for 8+ years. Color fundus photos, fundus autofluorescence images, near-infrared reflectance fundus images, and spectral domain optical coherence tomography scans were acquired during follow-up. Both patients, aged 45 and 50 years, had good visual acuities (>20/20) in the context of prolonged dark adaptation. Baseline color fundus photography demonstrated yellow-white, punctate lesions in the temporal macula that correlated with a reticular pattern on fundus autofluorescence and near-infrared reflectance imaging. Baseline spectral domain optical coherence tomography imaging revealed subretinal deposits that resemble reticular pseudodrusen described in age-related macular degeneration. During follow-up, these affected areas developed confluent thickening of the retinal pigment epithelial layer and disruption of the ellipsoid zone of photoreceptors before progressing to overt retinal pigment epithelium and outer retinal atrophy. Structural changes in early stages of late-onset retinal degeneration, revealed by multimodal imaging, resemble those of reticular pseudodrusen observed in age-related macular degeneration and other retinal diseases. Longitudinal follow-up of these lesions helps elucidate their progression to frank atrophy and may lend insight into the pathogenic mechanisms underlying diverse retinal degenerations.

Finite Element Analysis of Crack-Path Selection in a Brick and Mortar Structure

Science.gov (United States)

Sarrafi-Nour, Reza; Manoharan, Mohan; Johnson, Curtis A.

Many natural composite materials rely on organized architectures that span several length scales. The structures of natural shells such as nacre (mother-of-pearl) and conch are prominent examples of such organizations where the calcium carbonate platelets, the main constituent of natural shells, are held together in an organized fashion within an organic matrix. At one or multiple length scales, these organized arrangements often resemble a brick-and-mortar structure, with calcium carbonate platelets acting as bricks connected through the organic mortar phase.

Cellular structure of lean hydrogen flames in microgravity

Science.gov (United States)

Patnaik, G.; Kailasanath, K.

1990-01-01

Detailed, time-dependent, two-dimensional numerical simulations of premixed laminar flames have been used to study the initiation and subsequent development of cellular structures in lean hydrogen-air flames. The model includes detailed hydrogen-oxygen combustion with 24 elementary reactions of eight reactive species and a nitrogen diluent, molecular diffusion of all species, thermal conduction, viscosity, and convection. This model has been used to study the nonlinear evolution of cellular flame structure and shows that cell splitting, as observed in experiments, can be predicted numerically for sufficiently reactive mixtures. The structures that evolved also resembled the cellular structures observed in experiments. The present study shows that the 'cell-split limit' postulated from experimental observations is an intrinsic property of the mixture and that external factors such as heat losses are not necessary to cause this limit.

Effects of variable thermal diffusivity on the structure of convection

Science.gov (United States)

Shcheritsa, O. V.; Getling, A. V.; Mazhorova, O. S.

2018-03-01

The structure of multiscale convection in a thermally stratified plane horizontal fluid layer is investigated by means of numerical simulations. The thermal diffusivity is assumed to produce a thin boundary sublayer convectively much more unstable than the bulk of the layer. The simulated flow is a superposition of cellular structures with three different characteristic scales. In contrast to the largest convection cells, the smaller ones are localised in the upper portion of the layer. The smallest cells are advected by the larger-scale convective flows. The simulated flow pattern qualitatively resembles that observed on the Sun.

'Hair-on-end' skull changes resembling thalassemia caused by marrow expansion in uncorrected complex cyanotic heart disease

International Nuclear Information System (INIS)

Walor, David M.; Berdon, Walter E.; Westra, Sjirk J.

2005-01-01

''Hair-on-end'' skull changes resembling thalassemia were rarely described in the 1950s and 1960s in children with cyanotic congenital heart diseases; these changes were described almost entirely in patients with tetralogy of Fallot or D-transposition of the great arteries. As these lesions have become correctable, the osseous changes, never common, seem now only to exist in a small number of patients with uncorrectable complex cyanotic congenital heart disease who survive in a chronic hypoxic state. We present two cases: a case of marked marrow expansion in the skull of a 5-year-old boy with uncorrectable cyanotic heart disease studied by CT, and a second case of an 8-year-old with tetralogy of Fallot and pulmonary atresia studied by plain skull radiographs. The true incidence of these findings is unknown. (orig.)

Unsteady aerodynamic modelling of wind turbines

Energy Technology Data Exchange (ETDEWEB)

Coton, F.N.; Galbraith, R.A. [Univ. og Glasgow, Dept. of Aerospace Engineering, Glasgow (United Kingdom)

1997-08-01

The following current and future work is discussed: Collaborative wind tunnel based PIV project to study wind turbine wake structures in head-on and yawed flow. Prescribed wake model has been embedded in a source panel representation of the wind tunnel walls to allow comparison with experiment; Modelling of tower shadow using high resolution but efficient vortex model in tower shadow domain; Extension of model to yawing flow; Upgrading and tuning of unsteady aerodynamic model for low speed, thick airfoil flows. Glasgow has a considerable collection of low speed dynamic stall data. Currently, the Leishman - Beddoes model is not ideally suited to such flows. For example: Range of stall onset criteria used for dynamic stall prediction including Beddoes. Wide variation of stall onset prediction. Beddoes representation was developed primarily with reference to compressible flows. Analyses of low speed data from Glasgow indicate deficiencies in the current model; Predicted versus measured response during ramp down motion. Modification of the Beddoes representation is required to obtain a fit with the measured data. (EG)

Does the calcification of adamantinomatous craniopharyngioma resemble the calcium deposition of osteogenesis/odontogenesis?

Science.gov (United States)

Song-Tao, Qi; Xiao-Rong, Yan; Jun, Pan; Yong-Jian, Deng; Jin, Liang; Guang-Long, Huang; Yun-Tao, Lu; Jian, Ruan; Xiang-Zhao, Li; Jia-Ming, Xu

2014-02-01

Calcification in adamantinomatous craniopharyngioma (ACP) is troublesome for surgical intervention. The aim of this study was to examine the osteogenic proteins that play important roles in the calcium deposition of the odontogenic/osteogenic tissues in craniopharyngioma. Craniopharyngiomas (n = 89) were investigated for the presence and expression pattern of the osteoinductive/odontoinductive factor bone morphogenetic protein-2 (Bmp2) and two osteoblastic differentiation makers, Runt-related transcription factor-2 (Runx2) and Osterix, using immunohistochemistry and Western blotting. Our results showed that Bmp2, Runx2 and Osterix levels increased in cases with high calcification and correlated positively with the degree of calcification in ACP, whereas they showed little or no expression in squamous papillary craniopharyngioma. In ACP, Bmp2 was expressed primarily in the stellate reticulum and whorl-like array cells; Runx2 and Osterix tended to be expressed in calcification-related epithelia, including whorl-like array cells and epithelia in/around wet keratin and calcification lesions. Our study indicated, for the first time, that osteogenic factor Bmp2 may play an important role in the calcification of ACP via autocrine or paracrine mechanisms. Given the presence of osteogenic markers (Runx2 and Osterix), craniopharyngioma cells could differentiate into an osteoblast-like lineage, and the process of craniopharyngioma calcification resembles that which occurs in osteogenesis/odontogenesis. © 2014 John Wiley & Sons Ltd.

Monomeric Aβ(1-40) and Aβ(1-42) Peptides in Solution Adopt Very Similar Ramachandran Map Distributions That Closely Resemble Random Coil.

Science.gov (United States)

Roche, Julien; Shen, Yang; Lee, Jung Ho; Ying, Jinfa; Bax, Ad

2016-02-09

The pathogenesis of Alzheimer's disease is characterized by the aggregation and fibrillation of amyloid peptides Aβ(1-40) and Aβ(1-42) into amyloid plaques. Despite strong potential therapeutic interest, the structural pathways associated with the conversion of monomeric Aβ peptides into oligomeric species remain largely unknown. In particular, the higher aggregation propensity and associated toxicity of Aβ(1-42) compared to that of Aβ(1-40) are poorly understood. To explore in detail the structural propensity of the monomeric Aβ(1-40) and Aβ(1-42) peptides in solution, we recorded a large set of nuclear magnetic resonance (NMR) parameters, including chemical shifts, nuclear Overhauser effects (NOEs), and J couplings. Systematic comparisons show that at neutral pH the Aβ(1-40) and Aβ(1-42) peptides populate almost indistinguishable coil-like conformations. Nuclear Overhauser effect spectra collected at very high resolution remove assignment ambiguities and show no long-range NOE contacts. Six sets of backbone J couplings ((3)JHNHα, (3)JC'C', (3)JC'Hα, (1)JHαCα, (2)JNCα, and (1)JNCα) recorded for Aβ(1-40) were used as input for the recently developed MERA Ramachandran map analysis, yielding residue-specific backbone ϕ/ψ torsion angle distributions that closely resemble random coil distributions, the absence of a significantly elevated propensity for β-conformations in the C-terminal region of the peptide, and a small but distinct propensity for αL at K28. Our results suggest that the self-association of Aβ peptides into toxic oligomers is not driven by elevated propensities of the monomeric species to adopt β-strand-like conformations. Instead, the accelerated disappearance of Aβ NMR signals in D2O over H2O, particularly pronounced for Aβ(1-42), suggests that intermolecular interactions between the hydrophobic regions of the peptide dominate the aggregation process.

Transition-state structure in the yeast alcohol dehydrogenase reaction: the magnitude of solvent and alpha-secondary hydrogen isotope effects

International Nuclear Information System (INIS)

Welsh, K.M.; Creighton, D.J.; Klinman, J.P.

1980-01-01

Solvent and alpha-secondary isotope effects have been measured in the yeast alcohol dehydrogenase reaction, under conditions of a rate-limiting transfer of hydrogen between coenzyme and substrate. Determination of catalytic constants in H20 and D20 as a function of pH(D) has allowed the separation of solvent effects on pKa from kcat. The small effect of D20 on pKa is tentatively assigned to ionization of an active-site ZnOH 2 . The near absence of an isotope effect on kcat in the direction of alcohol oxidation rules out a mechanism involving concerted catalysis by an active-site base of hydride transfer. The near identity of kinetic and equilibrium alpha-secondary isotope effects in the direction of alcohol oxidation implicates a transition-state structure which resembles aldehyde with regard to bond hybridization properties. The result contrasts sharply with previously reported structure - reactivity correlations, which implicate a transition-state structure resembling alcohol with regard to charge properties. The significance of these findings to the mechanism of NAD(P)H-dependent redox reactions is discussed

Using Nature-Based Rehabilitation to Restart a Stalled Process of Rehabilitation in Individuals with Stress-Related Mental Illness

Directory of Open Access Journals (Sweden)

Eva Sahlin

2015-02-01

Full Text Available After a period of decrease, sick leave in Sweden due to psychiatric diagnoses is on the increase. The lack of established rehabilitation programmes for patients with stress-related mental disorders (SRMD has opened up for the use of garden/nature in a multimodal rehabilitation context (Nature-Based Rehabilitation, NBR. Region Västra Götaland (VGR started an NBR to offer additional rehabilitation for its employees on long-term sick leave due to SRMD, where initial care had not been sufficient. The aim was to explore whether the mental health and well-being of NBR participants had improved at the end of the NBR and at three follow-ups, and to explore the development of sick leave and health care utilization according to the NBR model (n = 57 and an occupational health service (OHS model (n = 45. Self-assessment instruments for measuring burnout, depression, anxiety and wellbeing, and data from regional and national registers were used. Results showed decreased scores on burnout, depression and anxiety, and increased well-being scores and significantly reduced health care utilization in the NBR group. A large movement from ordinary sickness benefit to rehabilitation benefit was observed, which was not observed in the OHS group. The two groups were in different rehabilitation phases, which limited comparisons. The results point to beneficial effects of using NBR for this patient group and for enhancing a stalled rehabilitation process.

Pathogenesis of Candida albicans infections in the alternative chorio-allantoic membrane chicken embryo model resembles systemic murine infections.

Directory of Open Access Journals (Sweden)

Ilse D Jacobsen

Full Text Available Alternative models of microbial infections are increasingly used to screen virulence determinants of pathogens. In this study, we investigated the pathogenesis of Candida albicans and C. glabrata infections in chicken embryos infected via the chorio-allantoic membrane (CAM and analyzed the virulence of deletion mutants. The developing immune system of the host significantly influenced susceptibility: With increasing age, embryos became more resistant and mounted a more balanced immune response, characterized by lower induction of proinflammatory cytokines and increased transcription of regulatory cytokines, suggesting that immunopathology contributes to pathogenesis. While many aspects of the chicken embryo response resembled murine infections, we also observed significant differences: In contrast to systemic infections in mice, IL-10 had a beneficial effect in chicken embryos. IL-22 and IL-17A were only upregulated after the peak mortality in the chicken embryo model occurred; thus, the role of the Th17 response in this model remains unclear. Abscess formation occurs frequently in murine models, whereas the avian response was dominated by granuloma formation. Pathogenicity of the majority of 15 tested C. albicans deletion strains was comparable to the virulence in mouse models and reduced virulence was associated with significantly lower transcription of proinflammatory cytokines. However, fungal burden did not correlate with virulence and for few mutants like bcr1Δ and tec1Δ different outcomes in survival compared to murine infections were observed. C. albicans strains locked in the yeast stage disseminated significantly more often from the CAM into the embryo, supporting the hypothesis that the yeast morphology is responsible for dissemination in systemic infections. These data suggest that the pathogenesis of C. albicans infections in the chicken embryo model resembles systemic murine infections but also differs in some aspects. Despite

Study of the stall delay phenomenon and of wind turbine blade dynamics using numerical approaches and NREL's wind tunnel tests

Energy Technology Data Exchange (ETDEWEB)

Breton, Simon-Philippe

2008-06-15

The production of electricity from wind has experienced an enormous growth worldwide in the last 20 years. It is now widely seen as a serious alternative to more conventional energy production methods. Improvements are however still possible to make it more cost-effective. This can be done through a better understanding of the fundamental phenomena involved in the interaction of the wind with the wind turbine rotor. This growth in the production of energy from wind is expected to continue at a similar rate in the years to come, helped by the installation of wind turbines at sea, that is becoming a hot topic in the wind energy field today. The phenomenon of stall delay affecting rotating wind turbine blades is an example of an aerodynamic phenomenon that is not yet fully understood. Several models exist to correct for this effect. Five such models were first tested within a vortex wake simulation code based on the modelling of a prescribed wake behind the rotor of the turbine. Comparison was made with wind tunnel test data acquired in head-on flow on a two-bladed 10.1 diameter wind turbine at the National Renewable Energy Laboratories (NREL) in 2000. It revealed a general overprediction of the stall delay effects, at the same time as great disparity was obtained between the different models. Conclusions from this work served as a starting point for a much more thorough investigation on this subject, where several models were tested in terms of different quantities using the same simulation code, and where the application of some of the models was improved. Overprediction of the loads was once again obtained when comparison was made to the NREL results in head-on flow, and none of the models was found to correctly represent the flow physics involved. The premises on which each of the models relies were discussed as a means of better understanding and modelling this phenomenon. The important issue of tip loss was also covered, and guidelines were suggested to improve

Nonparenchymal cells cultivated from explants of fibrotic liver resemble endothelial and smooth muscle cells from blood vessel walls

International Nuclear Information System (INIS)

Voss, B.; Rauterberg, J.; Pott, G.; Brehmer, U.; Allam, S.; Lehmann, R.; von Bassewitz, D.B.

1982-01-01

Tissue specimens from human fibrotic liver obtained by needle biopsy were cultured. Two cell types emerged from the tissue explants. From their morphology and biosynthetic products they resembled smooth muscle cells and endothelial cells from blood vessel walls. In the endothelial cells, factor VIII-associated protein was demonstrated by indirect immunofluorescence. Synthesis of collagen types I and III, basement membrane collagen types IV and V, and fibronectin by both cell types was observed by immunofluorescence microscopy. Homogeneous cultures of smooth muscle cells were observed in subcultures. After incubation with [ 14 C]glycine, collagen was isolated and characterized by CM cellulose chromatography, and consisted mainly of types I and III. These data suggest involvement of mesenchymal cells in hepatic fibrosis; they presumably originate from blood vessel or sinusoidal walls

Vaginal microbiota of adolescent girls prior to the onset of menarche resemble those of reproductive-age women.

Science.gov (United States)

Hickey, Roxana J; Zhou, Xia; Settles, Matthew L; Erb, Julie; Malone, Kristin; Hansmann, Melanie A; Shew, Marcia L; Van Der Pol, Barbara; Fortenberry, J Dennis; Forney, Larry J

2015-03-24

Puberty is an important developmental stage wherein hormonal shifts mediate the physical and physiological changes that lead to menarche, but until now, the bacterial composition of vaginal microbiota during this period has been poorly characterized. We performed a prospective longitudinal study of perimenarcheal girls to gain insight into the timing and sequence of changes that occur in the vaginal and vulvar microbiota during puberty. The study enrolled 31 healthy, premenarcheal girls between the ages of 10 and 12 years and collected vaginal and vulvar swabs quarterly for up to 3 years. Bacterial composition was characterized by Roche 454 pyrosequencing and classification of regions V1 to V3 of 16S rRNA genes. Contrary to expectations, lactic acid bacteria, primarily Lactobacillus spp., were dominant in the microbiota of most girls well before the onset of menarche in the early to middle stages of puberty. Gardnerella vaginalis was detected at appreciable levels in approximately one-third of subjects, a notable finding considering that this organism is commonly associated with bacterial vaginosis in adults. Vulvar microbiota closely resembled vaginal microbiota but often exhibited additional taxa typically associated with skin microbiota. Our findings suggest that the vaginal microbiota of girls begin to resemble those of adults well before the onset of menarche. This study addresses longitudinal changes in vaginal and vulvar microbial communities prior to and immediately following menarche. The research is significant because microbial ecology of the vagina is an integral aspect of health, including resistance to infections. The physiologic changes of puberty and initiation of cyclic menstruation are likely to have profound effects on vaginal microbiota, but almost nothing is known about changes that normally occur during this time. Our understanding has been especially hampered by the lack of thorough characterization of microbial communities using techniques

Muscle-type nicotinic receptor modulation by 2,6-dimethylaniline, a molecule resembling the hydrophobic moiety of lidocaine

Directory of Open Access Journals (Sweden)

Armando Alberola-Die

2016-11-01

Full Text Available To identify the molecular determinants responsible for lidocaine blockade of muscle-type nAChRs, we have studied the effects on this receptor of 2,6-dimethylaniline (DMA, which resembles lidocaine’s hydrophobic moiety. Torpedo marmorata nAChRs were microtransplanted to Xenopus oocytes and currents elicited by ACh (IACh, either alone or co-applied with DMA, were recorded. DMA reversibly blocked IACh and, similarly to lidocaine, exerted a closed-channel blockade, as evidenced by the enhancement of IACh blockade when DMA was pre-applied before its co-application with ACh, and hastened IACh decay. However, there were marked differences among its mechanisms of nAChR inhibition and those mediated by either the entire lidocaine molecule or diethylamine (DEA, a small amine resembling lidocaine’s hydrophilic moiety. Thereby, the IC50 for DMA, estimated from the dose-inhibition curve, was in the millimolar range, which is one order of magnitude higher than that for either DEA or lidocaine. Besides, nAChR blockade by DMA was voltage-independent in contrast to the increase of IACh inhibition at negative potentials caused by the more polar lidocaine or DEA molecules. Accordingly, virtual docking assays of DMA on nAChRs showed that this molecule binds predominantly at intersubunit crevices of the transmembrane-spanning domain, but also at the extracellular domain. Furthermore, DMA interacted with residues inside the channel pore, although only in the open-channel conformation. Interestingly, co-application of ACh with DEA and DMA, at their IC50s, had additive inhibitory effects on IACh and the extent of blockade was similar to that predicted by the allotopic model of interaction, suggesting that DEA and DMA bind to nAChRs at different loci. These results indicate that DMA mainly mimics the low potency and non-competitive actions of lidocaine on nAChRs, as opposed to the high potency and voltage-dependent block by lidocaine, which is emulated by the

An Investigation into the Mechanics of Windblown Dust Entrainment from Nickel Slag Surfaces Resembling Armoured Desert Pavements

Science.gov (United States)

Sanderson, Robert Steven

The purpose of this thesis is to investigate the dynamics of PM 10 emission from a nickel slag stockpile that closely resembles a desert pavement in physical characteristics. In the field, it was observed that slag surfaces develop by natural processes into a well-armoured surface over some period of time. The surface then consists of two distinct layers; a surficial armour layer containing only non-erodible gravel and cobble-sized clasts, and an underlying dust-laden layer, which contains a wide size range of slag particles, from clay-sized to cobble-sized. This surficial armour layer protects the underlying fines from wind entrainment, at least under typical wind conditions; however, particle emissions still do occur under high wind speeds. The dynamics of particle entrainment from within these surfaces are investigated herein. It is shown that the dynamics of the boundary layer flow over these lag surfaces are influenced by the inherent roughness and permeability of the surficial armour layer, such that the flow resembles those observed over and within vegetation canopies, and those associated with permeable gravel-bed river channels. Restriction of air flow within the permeable surface produces a high-pressure zone within the pore spaces, resulting in a Kelvin-Helmholtz shear instability, which triggers coherent motions in the form of repeating burst-sweep cycles. Using Laser Doppler Anemometry (LDA), it is demonstrated that the lower boundary layer is characterized by both Q4 sweeping motions and Q2 bursting motions, while the upper boundary layer is dominated by Q2 bursts. Pore air motions within the slag material were measured using buried pressure ports. It is shown that the mean pressure gradient which forms within the slag material results in net upward displacement of air, or wind pumping. However, this net upward motion is a result of rapid oscillatory motions which are directly driven by coherent boundary layer motions. It is also demonstrated that

Structure of synaptophysin: a hexameric MARVEL-domain channel protein.

Science.gov (United States)

Arthur, Christopher P; Stowell, Michael H B

2007-06-01

Synaptophysin I (SypI) is an archetypal member of the MARVEL-domain family of integral membrane proteins and one of the first synaptic vesicle proteins to be identified and cloned. Most all MARVEL-domain proteins are involved in membrane apposition and vesicle-trafficking events, but their precise role in these processes is unclear. We have purified mammalian SypI and determined its three-dimensional (3D) structure by using electron microscopy and single-particle 3D reconstruction. The hexameric structure resembles an open basket with a large pore and tenuous interactions within the cytosolic domain. The structure suggests a model for Synaptophysin's role in fusion and recycling that is regulated by known interactions with the SNARE machinery. This 3D structure of a MARVEL-domain protein provides a structural foundation for understanding the role of these important proteins in a variety of biological processes.

High-Throughput Screening of Vascular Endothelium-Destructive or Protective Microenvironments: Cooperative Actions of Extracellular Matrix Composition, Stiffness, and Structure.

Science.gov (United States)

Ding, Yonghui; Floren, Michael; Tan, Wei

2017-06-01

Pathological modification of the subendothelial extracellular matrix (ECM) has closely been associated with endothelial activation and subsequent cardiovascular disease progression. To understand regulatory mechanisms of these matrix modifications, the majority of previous efforts have focused on the modulation of either chemical composition or matrix stiffness on 2D smooth surfaces without simultaneously probing their cooperative effects on endothelium function on in vivo like 3D fibrous matrices. To this end, a high-throughput, combinatorial microarray platform on 2D and 3D hydrogel settings to resemble the compositions, stiffness, and structure of healthy and diseased subendothelial ECM has been established, and further their respective and combined effects on endothelial attachment, proliferation, inflammation, and junctional integrity have been investigated. For the first time, the results demonstrate that 3D fibrous structure resembling native ECM is a critical endothelium-protective microenvironmental factor by maintaining the stable, quiescent endothelium with strong resistance to proinflammatory stimuli. It is also revealed that matrix stiffening, in concert with chemical compositions resembling diseased ECM, particularly collagen III, could aggravate activation of nuclear factor kappa B, disruption of endothelium integrity, and susceptibility to proinflammatory stimuli. This study elucidates cooperative effects of various microenvironmental factors on endothelial activation and sheds light on new in vitro model for cardiovascular diseases. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Physical Interaction between Replication Protein A (RPA) and MRN: Involvement of RPA2 Phosphorylation and the N-terminus of RPA1

OpenAIRE

Oakley, Greg; Tillison, Kristin; Opiyo, Stephen; Glanzer, Jason; Horn, Jeffrey M.; Patrick, Steve M.

2009-01-01

Replication protein A (RPA) is a heterotrimeric protein consisting of RPA1, RPA2 and RPA3 subunits that binds to ssDNA with high affinity. The response to replication stress requires the recruitment of RPA and the MRE11/RAD50/NBS1 (MRN) complex. RPA bound to ssDNA stabilizes stalled replication forks by recruiting checkpoint proteins involved in fork stabilization. MRN can bind DNA structures encountered at stalled or collapsed replication forks, such as ssDNA-dsDNA junctions or breaks and pr...

Double inflation: A possible resolution of the large-scale structure problem

International Nuclear Information System (INIS)

Turner, M.S.; Villumsen, J.V.; Vittorio, N.; Silk, J.; Juszkiewicz, R.

1986-11-01

A model is presented for the large-scale structure of the universe in which two successive inflationary phases resulted in large small-scale and small large-scale density fluctuations. This bimodal density fluctuation spectrum in an Ω = 1 universe dominated by hot dark matter leads to large-scale structure of the galaxy distribution that is consistent with recent observational results. In particular, large, nearly empty voids and significant large-scale peculiar velocity fields are produced over scales of ∼100 Mpc, while the small-scale structure over ≤ 10 Mpc resembles that in a low density universe, as observed. Detailed analytical calculations and numerical simulations are given of the spatial and velocity correlations. 38 refs., 6 figs

DEWEK '98: 4. German wind power conference; DEWEK '98: 4. Deutsche Windenergie-Konferenz. Tagungsband

Energy Technology Data Exchange (ETDEWEB)

Gerdes, B. [ed.

1999-07-01

The conference report comprises 90 papers and posters on the following subjects: 1. Technological developments (e.g. use of adaptive structures systems, active stalle wind power systems, systems for early detection of errors); 2. Design and optimisation; 3. Wind forecasts; 4. Operation analyses (e.g. active and passive stall, collective loads, wind power systems in cold climates); 5. Wind power systems and the environment; 6. Offshore wind power generation; 7. Electric characteristics (e.g. modelling of flicker, energy conditioning in distribution systems with a high wind power share); 8. Economic efficiency (e.g. economic efficiency of offshore wind parks on the North Sea coast); 9. Network quality; 10. Rotor development (e.g. noise reduction); 11. Certification and methods of measurement. [German] Der Tagungsband enhaelt 90 Fach- und Posterbeitraege, die sich mit den folgenden Schwerpunkten befassen: 1. Technologische Entwicklungen (z.B. Einsatz von adaptiven Struktursystemen; Active-Stall-WKA; Fehlerfrueherkennungssystemen). 2. Auslegung und Optimierung. 3. Windprognosen. 4. Betriebsanalysen (z.B. Aktive Stall/Passive Stall im Vergleich; Lastkollektive von WKA; WKA in kaltem Klima). 5. Windenergieanlagen und Umwelt. 6. Offshore-Windenergienutzung. 7. Elektrische Eigenschaften (z.B. Modellierung des 'Flickerverhaltens' von WKA; Energiekonditionierung in Verteilnetzen mit hohem Windenergieanteil). 8. Wirtschaftlichkeit (z.B. Wirtschaftlichkeit von Offshore-Windparks der Norddeutschen Kuestenlinie). 9. Netzqualitaet. 10. Rotorentwicklung (z.B. Reduzierung der Schallabstrahlung von WKAs). 11. Zertifizierung von Messmethoden. (AKF)

DEWEK '98: 4. German wind power conference; DEWEK '98: 4. Deutsche Windenergie-Konferenz. Tagungsband

Energy Technology Data Exchange (ETDEWEB)

Gerdes, B [ed.

1999-07-01

The conference report comprises 90 papers and posters on the following subjects: 1. Technological developments (e.g. use of adaptive structures systems, active stalle wind power systems, systems for early detection of errors); 2. Design and optimisation; 3. Wind forecasts; 4. Operation analyses (e.g. active and passive stall, collective loads, wind power systems in cold climates); 5. Wind power systems and the environment; 6. Offshore wind power generation; 7. Electric characteristics (e.g. modelling of flicker, energy conditioning in distribution systems with a high wind power share); 8. Economic efficiency (e.g. economic efficiency of offshore wind parks on the North Sea coast); 9. Network quality; 10. Rotor development (e.g. noise reduction); 11. Certification and methods of measurement. [German] Der Tagungsband enhaelt 90 Fach- und Posterbeitraege, die sich mit den folgenden Schwerpunkten befassen: 1. Technologische Entwicklungen (z.B. Einsatz von adaptiven Struktursystemen; Active-Stall-WKA; Fehlerfrueherkennungssystemen). 2. Auslegung und Optimierung. 3. Windprognosen. 4. Betriebsanalysen (z.B. Aktive Stall/Passive Stall im Vergleich; Lastkollektive von WKA; WKA in kaltem Klima). 5. Windenergieanlagen und Umwelt. 6. Offshore-Windenergienutzung. 7. Elektrische Eigenschaften (z.B. Modellierung des 'Flickerverhaltens' von WKA; Energiekonditionierung in Verteilnetzen mit hohem Windenergieanteil). 8. Wirtschaftlichkeit (z.B. Wirtschaftlichkeit von Offshore-Windparks der Norddeutschen Kuestenlinie). 9. Netzqualitaet. 10. Rotorentwicklung (z.B. Reduzierung der Schallabstrahlung von WKAs). 11. Zertifizierung von Messmethoden. (AKF)

Numerical analysis of flow in a centrifugal compressor with circumferential grooves: influence of groove location and number on flow instability

Science.gov (United States)

Chen, X.; Qin, G.; Ai, Z.; Ji, Y.

2017-08-01

As an effective and economic method for flow range enhancement, circumferential groove casing treatment (CGCT) is widely used to increase the stall margin of compressors. Different from traditional grooved casing treatments, in which the grooves are always located over the rotor in both axial and radial compressors, one or several circumferential grooves are located along the shroud side of the diffuser passage in this paper. Numerical investigations were conducted to predict the performance of a low flow rate centrifugal compressor with CGCT in diffuser. Computational fluid dynamics (CFD) analysis is performed under stage environment in order to find the optimum location of the circumferential casing groove in consideration of stall margin enhancement and efficiency gain at design point, and the impact of groove number to the effect of this grooved casing treatment configuration in enhancing the stall margin of the compressor stage is studied. The results indicate that the centrifugal compressor with circumferential groove in vaned diffuser can obtain obvious improvement in the stall margin with sacrificing design efficiency a little. Efforts were made to study blade level flow mechanisms to determine how the CGCT impacts the compressor’s stall margin (SM) and performance. The flow structures in the passage, the tip gap, and the grooves as well as their mutual interactions were plotted and analysed.

Ionic core–shell dendrimers with a polycationic core: structural aspects and host–guest binding properties

NARCIS (Netherlands)

van de Coevering, R.; Bruijnincx, P.C.A.; Lutz, M.; Spek, A.L.; van Koten, G.; Klein Gebbink, R.J.M.

2007-01-01

The structural aspects and host–guest binding properties of ionic core–shell dendrimers [1]Br8 and [2]Br4, which bear a polycationic core and a neutral shell of Fréchet-type poly(benzyl aryl ether) dendrons, have been investigated by means of dendritic wedges [3]Br2 and [4]Br, that resemble one of

Calpain 1 inhibitor BDA-410 ameliorates α-klotho-deficiency phenotypes resembling human aging-related syndromes.

Science.gov (United States)

Nabeshima, Yoko; Washida, Miwa; Tamura, Masaru; Maeno, Akiteru; Ohnishi, Mutsuko; Shiroishi, Toshihiko; Imura, Akihiro; Razzaque, M Shawkat; Nabeshima, Yo-ichi

2014-08-01

Taking good care of elderly is a major challenge of our society, and thus identification of potential drug targets to reduce age-associated disease burden is desirable. α-klotho(-/-) (α-kl) is a short-lived mouse model that displays multiple phenotypes resembling human aging-related syndromes. Such ageing phenotype of α-kl(-/-) mice is associated with activation of a proteolytic enzyme, Calpain-1. We hypothesized that uncontrolled activation of calpain-1 might be causing age-related phenotypes in α-kl-deficient mice. We found that daily administration of BDA-410, a calpain-1 inhibitor, strikingly ameliorated multiple aging-related phenotypes. Treated mice showed recovery of reproductive ability, increased body weight, reduced organ atrophy, and suppression of ectopic calcifications, bone mineral density reduction, pulmonary emphysema and senile atrophy of skin. We also observed ectopic expression of FGF23 in calcified arteries of α-kl(-/-) mice, which might account for the clinically observed association of increased FGF23 level with increased risk of cardiovascular mortality. These findings allow us to propose that modulation of calpain-1 activity is a potential therapeutic option for delaying age-associated organ pathology, particularly caused by the dysregulation of mineral ion homeostasis.

Light scattering measurements supporting helical structures for chromatin in solution.

Science.gov (United States)

Campbell, A M; Cotter, R I; Pardon, J F

1978-05-01

Laser light scattering measurements have been made on a series of polynucleosomes containing from 50 to 150 nucleosomes. Radii of gyration have been determined as a function of polynucleosome length for different ionic strength solutions. The results suggest that at low ionic strength the chromatin adopts a loosely helical structure rather than a random coil. The helix becomes more regular on increasing the ionic strength, the dimension resembling those proposed by Finch and Klug for their solenoid model.

Net (ERP/SAP2) one of the Ras-inducible TCFs, has a novel inhibitory domain with resemblance to the helix-loop-helix motif.

Science.gov (United States)

Maira, S M; Wurtz, J M; Wasylyk, B

1996-11-01

The three ternary complex factors (TCFs), Net (ERP/ SAP-2), ELK-1 and SAP-1, are highly related ets oncogene family members that participate in the response of the cell to Ras and growth signals. Understanding the different roles of these factors will provide insights into how the signals result in coordinate regulation of the cell. We show that Net inhibits transcription under basal conditions, in which SAP-1a is inactive and ELK-1 stimulates. Repression is mediated by the NID, the Net Inhibitory Domain of about 50 amino acids, which autoregulates the Net protein and also inhibits when it is isolated in a heterologous fusion protein. Net is particularly sensitive to Ras activation. Ras activates Net through the C-domain, which is conserved between the three TCFs, and the NID is an efficient inhibitor of Ras activation. The NID, as well as more C-terminal sequences, inhibit DNA binding. Net is more refractory to DNA binding than the other TCFs, possibly due to the presence of multiple inhibitory elements. The NID may adopt a helix-loop-helix (HLH) structure, as evidenced by homology to other HLH motifs, structure predictions, model building and mutagenesis of critical residues. The sequence resemblance with myogenic factors suggested that Net may form complexes with the same partners. Indeed, we found that Net can interact in vivo with the basic HLH factor, E47. We propose that Net is regulated at the level of its latent DNA-binding activity by protein interactions and/or phosphorylation. Net may form complexes with HLH proteins as well as SRF on specific promotor sequences. The identification of the novel inhibitory domain provides a new inroad into exploring the different roles of the ternary complex factors in growth control and transformation.

Identification of genes involved in low aminoglycoside-induced SOS response in Vibrio cholerae: a role for transcription stalling and Mfd helicase.

Science.gov (United States)

Baharoglu, Zeynep; Babosan, Anamaria; Mazel, Didier

2014-02-01

Sub-inhibitory concentrations (sub-MIC) of antibiotics play a very important role in selection and development of resistances. Unlike Escherichia coli, Vibrio cholerae induces its SOS response in presence of sub-MIC aminoglycosides. A role for oxidized guanine residues was observed, but the mechanisms of this induction remained unclear. To select for V. cholerae mutants that do not induce low aminoglycoside-mediated SOS induction, we developed a genetic screen that renders induction of SOS lethal. We identified genes involved in this pathway using two strategies, inactivation by transposition and gene overexpression. Interestingly, we obtained mutants inactivated for the expression of proteins known to destabilize the RNA polymerase complex. Reconstruction of the corresponding mutants confirmed their specific involvement in induction of SOS by low aminoglycoside concentrations. We propose that DNA lesions formed on aminoglycoside treatment are repaired through the formation of single-stranded DNA intermediates, inducing SOS. Inactivation of functions that dislodge RNA polymerase leads to prolonged stalling on these lesions, which hampers SOS induction and repair and reduces viability under antibiotic stress. The importance of these mechanisms is illustrated by a reduction of aminoglycoside sub-MIC. Our results point to a central role for transcription blocking at DNA lesions in SOS induction, so far underestimated.

Test of 134Cs, 85,89Sr leaching rate in a resemble vitrifiable cement waste form

International Nuclear Information System (INIS)

Lin Meiqiong; Wei Feng; Yin Qi; Fan Xianhua; Xu Shengli; Li Yongde

2003-01-01

A novel material--resemble vitrifiable cement for conditioning low and mediate level radioactive waste has been developed. Waste form has been characterized for their physical and chemical performance, phase composition. The cement formulation has been patented. In this experiment the cement is mixed with simulated wastes spiked with 134 Cs and 85,89 Sr by 5 min at least. The Ratio of the waste to the cement is 0.45-0.55. The mixture is packed into cylindrical molds which has the same dimension of diameter and height . The grouts are cured for a period of 28 d in a room temperature curing chamber at an atmospheric pressure. The cured waste form is then completely immersed into deionized water. According to standard GB7023-86, leaching rate of 134 Cs and 85,89 Sr are measured. The result shows that the leaching rate of the species 134 Cs and 85,89 Sr is to be on the order 10 -4 and 10 -5 on the 42 d immersion, respectively and is better than that of commercial cement

What determines the structures of native folds of proteins?

International Nuclear Information System (INIS)

Trovato, Antonio; Hoang, Trinh X; Banavar, Jayanth R; Maritan, Amos; Seno, Flavio

2005-01-01

We review a simple physical model (Hoang et al 2004 Proc. Natl Acad. Sci. USA 101 7960, Banavar et al 2004 Phys. Rev. E at press) which captures the essential physico-chemical ingredients that determine protein structure, such as the inherent anisotropy of a chain molecule, the geometrical and energetic constraints placed by hydrogen bonds, sterics, and hydrophobicity. Within this framework, marginally compact conformations resembling the native state folds of proteins emerge as competing minima in the free energy landscape. Here we demonstrate that a hydrophobic-polar (HP) sequence composed of regularly repeated patterns has as its ground state a β-helical structure remarkably similar to a known architecture in the Protein Data Bank

Simultaneous realization of slow and fast acoustic waves using a fractal structure of Koch curve.

Science.gov (United States)

Ding, Jin; Fan, Li; Zhang, Shu-Yi; Zhang, Hui; Yu, Wei-Wei

2018-01-24

An acoustic metamaterial based on a fractal structure, the Koch curve, is designed to simultaneously realize slow and fast acoustic waves. Owing to the multiple transmitting paths in the structure resembling the Koch curve, the acoustic waves travelling along different paths interfere with each other. Therefore, slow waves are created on the basis of the resonance of a Koch-curve-shaped loop, and meanwhile, fast waves even with negative group velocities are obtained due to the destructive interference of two acoustic waves with opposite phases. Thus, the transmission of acoustic wave can be freely manipulated with the Koch-curve shaped structure.

An analysis on equal width quantization and linearly separable subcode encoding-based discretization and its performance resemblances

Directory of Open Access Journals (Sweden)

Lim Meng-Hui

2011-01-01

Full Text Available Abstract Biometric discretization extracts a binary string from a set of real-valued features per user. This representative string can be used as a cryptographic key in many security applications upon error correction. Discretization performance should not degrade from the actual continuous features-based classification performance significantly. However, numerous discretization approaches based on ineffective encoding schemes have been put forward. Therefore, the correlation between such discretization and classification has never been made clear. In this article, we aim to bridge the gap between continuous and Hamming domains, and provide a revelation upon how discretization based on equal-width quantization and linearly separable subcode encoding could affect the classification performance in the Hamming domain. We further illustrate how such discretization can be applied in order to obtain a highly resembled classification performance under the general Lp distance and the inner product metrics. Finally, empirical studies conducted on two benchmark face datasets vindicate our analysis results.

Ectopic lymphoid structures support ongoing production of class-switched autoantibodies in rheumatoid synovium.

Directory of Open Access Journals (Sweden)

Frances Humby

2009-01-01

Full Text Available Follicular structures resembling germinal centres (GCs that are characterized by follicular dendritic cell (FDC networks have long been recognized in chronically inflamed tissues in autoimmune diseases, including the synovium of rheumatoid arthritis (RA. However, it is debated whether these ectopic structures promote autoimmunity and chronic inflammation driving the production of pathogenic autoantibodies. Anti-citrullinated protein/peptide antibodies (ACPA are highly specific markers of RA, predict a poor prognosis, and have been suggested to be pathogenic. Therefore, the main study objectives were to determine whether ectopic lymphoid structures in RA synovium: (i express activation-induced cytidine deaminase (AID, the enzyme required for somatic hypermutation and class-switch recombination (CSR of Ig genes; (ii support ongoing CSR and ACPA production; and (iii remain functional in a RA/severe combined immunodeficiency (SCID chimera model devoid of new immune cell influx into the synovium.Using immunohistochemistry (IHC and quantitative Taqman real-time PCR (QT-PCR in synovial tissue from 55 patients with RA, we demonstrated that FDC+ structures invariably expressed AID with a distribution resembling secondary lymphoid organs. Further, AID+/CD21+ follicular structures were surrounded by ACPA+/CD138+ plasma cells, as demonstrated by immune reactivity to citrullinated fibrinogen. Moreover, we identified a novel subset of synovial AID+/CD20+ B cells outside GCs resembling interfollicular large B cells. In order to gain direct functional evidence that AID+ structures support CSR and in situ manufacturing of class-switched ACPA, 34 SCID mice were transplanted with RA synovium and humanely killed at 4 wk for harvesting of transplants and sera. Persistent expression of AID and Igamma-Cmu circular transcripts (identifying ongoing IgM-IgG class-switching was observed in synovial grafts expressing FDCs/CD21L. Furthermore, synovial mRNA levels of AID

Ectopic lymphoid structures support ongoing production of class-switched autoantibodies in rheumatoid synovium.

Science.gov (United States)

Humby, Frances; Bombardieri, Michele; Manzo, Antonio; Kelly, Stephen; Blades, Mark C; Kirkham, Bruce; Spencer, Jo; Pitzalis, Costantino

2009-01-13

Follicular structures resembling germinal centres (GCs) that are characterized by follicular dendritic cell (FDC) networks have long been recognized in chronically inflamed tissues in autoimmune diseases, including the synovium of rheumatoid arthritis (RA). However, it is debated whether these ectopic structures promote autoimmunity and chronic inflammation driving the production of pathogenic autoantibodies. Anti-citrullinated protein/peptide antibodies (ACPA) are highly specific markers of RA, predict a poor prognosis, and have been suggested to be pathogenic. Therefore, the main study objectives were to determine whether ectopic lymphoid structures in RA synovium: (i) express activation-induced cytidine deaminase (AID), the enzyme required for somatic hypermutation and class-switch recombination (CSR) of Ig genes; (ii) support ongoing CSR and ACPA production; and (iii) remain functional in a RA/severe combined immunodeficiency (SCID) chimera model devoid of new immune cell influx into the synovium. Using immunohistochemistry (IHC) and quantitative Taqman real-time PCR (QT-PCR) in synovial tissue from 55 patients with RA, we demonstrated that FDC+ structures invariably expressed AID with a distribution resembling secondary lymphoid organs. Further, AID+/CD21+ follicular structures were surrounded by ACPA+/CD138+ plasma cells, as demonstrated by immune reactivity to citrullinated fibrinogen. Moreover, we identified a novel subset of synovial AID+/CD20+ B cells outside GCs resembling interfollicular large B cells. In order to gain direct functional evidence that AID+ structures support CSR and in situ manufacturing of class-switched ACPA, 34 SCID mice were transplanted with RA synovium and humanely killed at 4 wk for harvesting of transplants and sera. Persistent expression of AID and Igamma-Cmu circular transcripts (identifying ongoing IgM-IgG class-switching) was observed in synovial grafts expressing FDCs/CD21L. Furthermore, synovial mRNA levels of AID were

Wing Leading Edge Concepts for Noise Reduction

Science.gov (United States)

Shmilovich, Arvin; Yadlin, Yoram; Pitera, David M.

2010-01-01

This study focuses on the development of wing leading edge concepts for noise reduction during high-lift operations, without compromising landing stall speeds, stall characteristics or cruise performance. High-lift geometries, which can be obtained by conventional mechanical systems or morphing structures have been considered. A systematic aerodynamic analysis procedure was used to arrive at several promising configurations. The aerodynamic design of new wing leading edge shapes is obtained from a robust Computational Fluid Dynamics procedure. Acoustic benefits are qualitatively established through the evaluation of the computed flow fields.

The identical-twin transfusion syndrome: a source of error in estimating IQ resemblance and heritability.

Science.gov (United States)

Munsinger, H

1977-01-01

Published studies show that among identical twins, lower birthweight is associated with lower adult intelligence. However, no such relation between birthweight and adult IQ exists among fraternal twins. A likely explanation for the association between birthweight and intelligence among identical twins is the identical twin transfusion syndrome which occurs only between some monochorionic identical twin pairs. The IQ scores from separated identical twins were reanalysed to explore the consequences of identical twin transfusion syndrome for IQ resemblance and heritability. Among 129 published cases of identical twin pairs reared apart, 76 pairs contained some birthweight information. The 76 pairs were separated into three classes: 23 pairs in which there was clear evidence of a substantial birthweight differences (indicating the probable existence of the identical twin transfusion syndrome), 27 pairs in which the information on birthweight was ambiguous (?), and 26 pairs in which there was clear evidence that the twins were similar in birthweight. The reanalyses showed: (1) birthweight differences are positively associated with IQ differences in the total sample of separated identical twins; (2) within the group of 23 twin pairs who showed large birthweight differences, there was a positive relation between birthweight differences and IQ differences; (3) when heritability of IQ is estimated for those twins who do not suffer large birthweight differences, the resemblance (and thus, h2/b) of the separated identical twins' IG is 0-95. Given that the average reliability of the individual IQ test is around 0-95, these data suggest that genetic factors and errors of measurement cause the individual differences in IQ among human beings. Because of the identical twin transfusion syndrome, previous studies of MZ twins have underestimated the effect of genetic factors on IQ. An analysis of the IQs for heavier and lighter birthweight twins suggests that the main effect of the

Zic deficiency in the cortical marginal zone and meninges results in cortical lamination defects resembling those in type II lissencephaly.

Science.gov (United States)

Inoue, Takashi; Ogawa, Masaharu; Mikoshiba, Katsuhiko; Aruga, Jun

2008-04-30

The formation of the highly organized cortical structure depends on the production and correct placement of the appropriate number and types of neurons. The Zic family of zinc-finger transcription factors plays essential roles in regulating the proliferation and differentiation of neuronal progenitors in the medial forebrain and the cerebellum. Examination of the expression of Zic genes demonstrated that Zic1, Zic2, and Zic3 were expressed by the progenitor cells in the septum and cortical hem, the sites of generation of the Cajal-Retzius (CR) cells. Immunohistochemical studies have revealed that Zic proteins were abundantly expressed in the meningeal cells and that the majority of the CR cells distributed in the medial and dorsal cortex also expressed Zic proteins in the mid-late embryonic and postnatal cortical marginal zones. During embryonic cortical development, Zic1/Zic3 double-mutant and hypomorphic Zic2 mutant mice showed a reduction in the number of CR cells in the rostral cortex, whereas the cell number remained unaffected in the caudal cortex. These mutants also showed mislocalization of the CR cells and cortical lamination defects, resembling the changes noted in type II (cobblestone) lissencephaly, throughout the brain. In the Zic1/3 mutant, reduced proliferation of the meningeal cells was observed before the thinner and disrupted organization of the pial basement membrane (BM) with reduced expression of the BM components and the meningeal cell-derived secretory factor. These defects correlated with the changes in the end feet morphology of the radial glial cells. These findings indicate that the Zic genes play critical roles in cortical development through regulating the proliferation of meningeal cells and the pial BM assembly.

Brain structural changes in schizoaffective disorder compared to schizophrenia and bipolar disorder.

Science.gov (United States)

Amann, B L; Canales-Rodríguez, E J; Madre, M; Radua, J; Monte, G; Alonso-Lana, S; Landin-Romero, R; Moreno-Alcázar, A; Bonnin, C M; Sarró, S; Ortiz-Gil, J; Gomar, J J; Moro, N; Fernandez-Corcuera, P; Goikolea, J M; Blanch, J; Salvador, R; Vieta, E; McKenna, P J; Pomarol-Clotet, E

2016-01-01

Brain structural changes in schizoaffective disorder, and how far they resemble those seen in schizophrenia and bipolar disorder, have only been studied to a limited extent. Forty-five patients meeting DSM-IV and RDC criteria for schizoaffective disorder, groups of patients with 45 matched schizophrenia and bipolar disorder, and 45 matched healthy controls were examined using voxel-based morphometry (VBM). Analyses comparing each patient group with the healthy control subjects found that the patients with schizoaffective disorder and the patients with schizophrenia showed widespread and overlapping areas of significant volume reduction, but the patients with bipolar disorder did not. A subsequent analysis compared the combined group of patients with the controls followed by extraction of clusters. In regions where the patients differed significantly from the controls, no significant differences in mean volume between patients with schizoaffective disorder and patients with schizophrenia in any of five regions of volume reduction were found, but mean volumes in the patients with bipolar disorder were significantly smaller in three of five. The findings provide evidence that, in terms of structural gray matter brain abnormality, schizoaffective disorder resembles schizophrenia more than bipolar disorder. © 2015 The Authors. Acta Psychiatrica Scandinavica Published by John Wiley & Sons Ltd.

Altered minor-groove hydrogen bonds in DNA block transcription elongation by T7 RNA polymerase.

Science.gov (United States)

Tanasova, Marina; Goeldi, Silvan; Meyer, Fabian; Hanawalt, Philip C; Spivak, Graciela; Sturla, Shana J

2015-05-26

DNA transcription depends upon the highly efficient and selective function of RNA polymerases (RNAPs). Modifications in the template DNA can impact the progression of RNA synthesis, and a number of DNA adducts, as well as abasic sites, arrest or stall transcription. Nonetheless, data are needed to understand why certain modifications to the structure of DNA bases stall RNA polymerases while others are efficiently bypassed. In this study, we evaluate the impact that alterations in dNTP/rNTP base-pair geometry have on transcription. T7 RNA polymerase was used to study transcription over modified purines and pyrimidines with altered H-bonding capacities. The results suggest that introducing wobble base-pairs into the DNA:RNA heteroduplex interferes with transcriptional elongation and stalls RNA polymerase. However, transcriptional stalling is not observed if mismatched base-pairs do not H-bond. Together, these studies show that RNAP is able to discriminate mismatches resulting in wobble base-pairs, and suggest that, in cases of modifications with minor steric impact, DNA:RNA heteroduplex geometry could serve as a controlling factor for initiating transcription-coupled DNA repair. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

The crystal structure of elongation factor G complexed with GDP, at 2.7 A resolution.

OpenAIRE

Czworkowski, J; Wang, J; Steitz, T A; Moore, P B

1994-01-01

Elongation factor G (EF-G) catalyzes the translocation step of protein synthesis in bacteria, and like the other bacterial elongation factor, EF-Tu--whose structure is already known--it is a member of the GTPase superfamily. We have determined the crystal structure of EF-G--GDP from Thermus thermophilus. It is an elongated molecule whose large, N-terminal domain resembles the G domain of EF-Tu, except for a 90 residue insert, which covers a surface that is involved in nucleotide exchange in E...

Structural Transformation — How Does Thailand Compare?

OpenAIRE

Vladimir Klyuev

2015-01-01

Thailand stands out in international comparison as a country with a high dispersion of productivity across sectors. It has especially low labor productivity in agriculture—a sector that employs a much larger share of the population than is typical for a country at Thailand’s level of income. This suggests large potential productivity gains from labor reallocation across sectors, but that process—which made a significant contribution to Thailand’s growth in the past—appears to have stalled lat...

Numerical techniques for the improved performance of a finite element approach to wind turbine aeroelastics

Energy Technology Data Exchange (ETDEWEB)

Anderson, M.B. [Renewable Energy Systems Ltd., Hemel Hempstead (United Kingdom)

1996-09-01

It is possible to compute the aeroelastic response of a horizontal axis wind turbine comprising; Structural: rotor substructure 144 dof, tower substructure 48 dof, induction, synchronous or variable speed, and gearbox. Aerodynamic: 3 blades (10 elements per blade), dynamic stall, and 6 different aerofoil types with combination of fixed or pitching elements. Control: stall or power regulation or speed control and shutdowns, wind shear, and tower shadow. Turbulence: 8 radial points, 32 circumferential, and 3 components. On a DEC Alpha Workstation the code will simulate the response inclose to real-time. As the code is presently formulated deflections from the initial starting point have to be small and therefore its ability to fully analyse very flexible structures is limited. (EG)

Family Resemblances: Human Reproductive Cloning as an Example for Reconsidering the Mutual Relationships between Bioethics and Science Fiction.

Science.gov (United States)

Hansen, Solveig L

2018-03-08

In the traditions of narrative ethics and casuistry, stories have a well-established role. Specifically, illness narratives provide insight into patients' perspectives and histories. However, because they tend to see fiction as an aesthetic endeavour, practitioners in these traditions often do not realize that fictional stories are valuable moral sources of their own. In this paper I employ two arguments to show the mutual relationship between bioethics and fiction, specifically, science fiction. First, both discourses use imagination to set a scene and determine a perspective. Second, bioethics and science fiction share the family resemblance of expressing moral beliefs. I then consider how understanding bioethics and science fiction as interrelated discourses can be the basis of a methodology for inquiry into relational autonomy in the context of biotechnologies and medicine. As an example of this methodology, I analyse Fay Weldon's novel The Cloning of Joanna May (1989).

mRNA decay proteins are targeted to poly(A+ RNA and dsRNA-containing cytoplasmic foci that resemble P-bodies in Entamoeba histolytica.

Directory of Open Access Journals (Sweden)

Itzel López-Rosas

Full Text Available In higher eukaryotes, mRNA degradation and RNA-based gene silencing occur in cytoplasmic foci referred to as processing bodies (P-bodies. In protozoan parasites, the presence of P-bodies and their putative role in mRNA decay have yet to be comprehensively addressed. Identification of P-bodies might provide information on how mRNA degradation machineries evolved in lower eukaryotes. Here, we used immunofluorescence and confocal microscopy assays to investigate the cellular localization of mRNA degradation proteins in the human intestinal parasite Entamoeba histolytica and found evidence of the existence of P-bodies. Two mRNA decay factors, namely the EhXRN2 exoribonuclease and the EhDCP2 decapping enzyme, were localized in cytoplasmic foci in a pattern resembling P-body organization. Given that amoebic foci appear to be smaller and less rounded than those described in higher eukaryotes, we have named them "P-body-like structures". These foci contain additional mRNA degradation factors, including the EhCAF1 deadenylase and the EhAGO2-2 protein involved in RNA interference. Biochemical analysis revealed that EhCAF1 co-immunoprecipitated with EhXRN2 but not with EhDCP2 or EhAGO2-2, thus linking deadenylation to 5'-to-3' mRNA decay. The number of EhCAF1-containing foci significantly decreased after inhibition of transcription and translation with actinomycin D and cycloheximide, respectively. Furthermore, results of RNA-FISH assays showed that (i EhCAF1 colocalized with poly(A(+ RNA and (ii during silencing of the Ehpc4 gene by RNA interference, EhAGO2-2 colocalized with small interfering RNAs in cytoplasmic foci. Our observation of decapping, deadenylation and RNA interference proteins within P-body-like foci suggests that these structures have been conserved after originating in the early evolution of eukaryotic lineages. To the best of our knowledge, this is the first study to report on the localization of mRNA decay proteins within P

Structure of the hepatitis C virus IRES bound to the human 80S ribosome: remodeling of the HCV IRES.

Science.gov (United States)

Boehringer, Daniel; Thermann, Rolf; Ostareck-Lederer, Antje; Lewis, Joe D; Stark, Holger

2005-11-01

Initiation of translation of the hepatitis C virus (HCV) polyprotein is driven by an internal ribosome entry site (IRES) RNA that bypasses much of the eukaryotic translation initiation machinery. Here, single-particle electron cryomicroscopy has been used to study the mechanism of HCV IRES-mediated initiation. A HeLa in vitro translation system was used to assemble human IRES-80S ribosome complexes under near physiological conditions; these were stalled before elongation. Domain 2 of the HCV IRES is bound to the tRNA exit site, touching the L1 stalk of the 60S subunit, suggesting a mechanism for the removal of the HCV IRES in the progression to elongation. Domain 3 of the HCV IRES positions the initiation codon in the ribosomal mRNA binding cleft by binding helix 28 at the head of the 40S subunit. The comparison with the previously published binary 40S-HCV IRES complex reveals structural rearrangements in the two pseudoknot structures of the HCV IRES in translation initiation.

Resemblance in dietary intakes between urban low-income African-American adolescents and their mothers: the healthy eating and active lifestyles from school to home for kids study.

Science.gov (United States)

Wang, Youfa; Li, Ji; Caballero, Benjamin

2009-01-01

To examine the association and predictors of dietary intake resemblance between urban low-income African-American adolescents and their mothers. Detailed dietary data collected from 121 child-parent pairs in Chicago during fall 2003 were used. The association was assessed using correlation coefficients, kappa, and percentage of agreement, as well as logistic regression models. Overall, the association was weak as indicated by correlations and other measures. None of the mother-son correlations for nutrients and food groups were greater than 0.20. Mother-daughter pairs had stronger correlations (0.26 for energy and 0.30 for fat). The association was stronger in normal-weight mothers than in mothers with overweight or obesity. Logistic models showed that mother being a current smoker, giving child more pocket money, and allowing child to eat or purchase snacks without parental permission or presence predicted a higher probability of resemblance in undesirable eating patterns, such as high-energy, high-fat, and high-snack intakes (P<0.05). Mother-child diet association was generally weak, and varied considerably across groups and intake variables in this homogenous population. Some maternal characteristics seem to affect the association.

The effect of inlet distorted flow on steady and unsteady performance of a centrifugal compressor

International Nuclear Information System (INIS)

Park, Jae Hyoung; Kang, Shin Hyoung

2005-01-01

Effects of inlet distorted flow on performance, stall and surge are experimentally investigated for a high-speed centrifugal compressor. Tested results for the distorted inlet flow cases are compared with the result of the undistorted one. The performance of compressor is slightly deteriorated due to the inlet distortion. The inlet distortion does not affect the number of stall cell and the propagation velocity. It also does not change stall inception flow rate. However, as the distortion increases, stall starts at the higher flow rate for low speed at the lower flow rate for high speed. For 50,000 rpm stall occurs as the flow rate decreases, however disappears for the smaller flow rate. This is due to the interaction of surge and stall. After the stall and surge interact, the number of stall cell decreases

Conformational transition paths harbor structures useful for aiding drug discovery and understanding enzymatic mechanisms in protein kinases.

Science.gov (United States)

Wong, Chung F

2016-01-01

This short article examines the usefulness of fast simulations of conformational transition paths in elucidating enzymatic mechanisms and guiding drug discovery for protein kinases. It applies the transition path method in the MOIL software package to simulate the paths of conformational transitions between six pairs of structures from the Protein Data Bank. The structures along the transition paths were found to resemble experimental structures that mimic transient structures believed to form during enzymatic catalysis or conformational transitions, or structures that have drug candidates bound. These findings suggest that such simulations could provide quick initial insights into the enzymatic mechanisms or pathways of conformational transitions of proteins kinases, or could provide structures useful for aiding structure-based drug design. © 2015 The Protein Society.

Phenolic extract of Parkia biglobosa fruit pulp stalls aflatoxin B1 – mediated oxidative rout in the liver of male rats

Directory of Open Access Journals (Sweden)

Taofeek O. Ajiboye

Full Text Available The effect of phenolic extract of Parkia biglobosa (Jacq. R. Br. ex G. Don, Fabaceae, pulp on aflatoxin B1 induced oxidative imbalance in rat liver was evaluated. Thirty-five male rats were randomized into seven groups of five animals each. Rats in group A served as control and received vehicle for drug administration (0.5% DMSO once daily at 24 h intervals for six weeks. Rats in groups B, D, E, F and G, received aflatoxin B1 (167 μg/kg body weight in 0.5% DMSO for three weeks, starting from the third week of the experimental period. Rats in Group C received 400 mg/kg bodyweight of the extract for six weeks, while groups D, E and F rats were treated with 100, 200 and 400 mg/kg bodyweight of the extract for six weeks respectively. Group G rats received 100 mg/kg body weight of vitamin C. Aflatoxin B1-mediated decrease in the activities of superoxide dismutase, catalase, glutathione peroxidase, glutathione reductase and glucose-6-phosphate dehydrogenase were significantly attenuated. Aflatoxin B1 mediated the elevation in malondialdehyde, conjugated dienes, lipid hydroperoxides, protein carbonyl, and significantly lowered DNA fragmentation percentage. Overall, the phenolic extract of P. biglobosa pulp stalls aflatoxin B1-mediated oxidative rout by enhancing antioxidant enzyme activities leading to decreased lipid peroxidation, protein oxidation and DNA fragmentation.

'Hair-on-end' skull changes resembling thalassemia caused by marrow expansion in uncorrected complex cyanotic heart disease

Energy Technology Data Exchange (ETDEWEB)

Walor, David M.; Berdon, Walter E. [Columbia University Medical Center, Department of Radiology Children' s Hospital of New York, New York, NY (United States); Westra, Sjirk J. [Massachusetts General Hospital, Department of Radiology, Boston, MA (United States)

2005-07-01

''Hair-on-end'' skull changes resembling thalassemia were rarely described in the 1950s and 1960s in children with cyanotic congenital heart diseases; these changes were described almost entirely in patients with tetralogy of Fallot or D-transposition of the great arteries. As these lesions have become correctable, the osseous changes, never common, seem now only to exist in a small number of patients with uncorrectable complex cyanotic congenital heart disease who survive in a chronic hypoxic state. We present two cases: a case of marked marrow expansion in the skull of a 5-year-old boy with uncorrectable cyanotic heart disease studied by CT, and a second case of an 8-year-old with tetralogy of Fallot and pulmonary atresia studied by plain skull radiographs. The true incidence of these findings is unknown. (orig.)

Epithelial proliferation in small ducts of salivary cystadenoma resembling atypical ductal hyperplasia of breast.

Science.gov (United States)

Fahim, Lisa; Weinreb, Ilan; Alexander, Cherupushpam; Perez Ordoñez, Bayardo

2008-09-01

Salivary gland cystadenomas are cystic neoplasms with diverse architecture and cytology. Cystadenomas may have a considerable intracystic epithelial component, but an epithelial proliferation in small ducts and cysts resembling atypical ductal hyperplasia of breast has not been documented. The patient was a 68-year-old man with a slow growing right submandibular mass. He has no recurrence 13 months after resection. The tumor was polycystic and measured 3.0 x 2.5 x 2.5 cm. The epithelium of the larger cysts was composed of flat, cuboidal, columnar, and apocrine-like cells. Many of the larger cysts showed "Roman bridges", epithelial tufting, and papillae. The smaller cysts and ducts had apocrine-like cells forming secondary glandular lumens. The ductal cells were surrounded by clear myoepithelial cells. Nuclear pleomorphism and hyperchromasia was seen in the apocrine-like cells. Adjacent to the larger cysts, there was an adenomatoid proliferation of small ducts surrounded by myoepithelial cells. No mitotic activity, necrosis, or stromal invasion was identified. The ductal cells were diffusely positive for keratin 7 and androgen receptors with focal expression of keratin 19 and high-molecular weight keratin. S-100, estrogen and progesterone receptors, and BRST-2 were negative in the ductal cells. Recognition of a prominent intraductal epithelial component in cystadenomas is important to avoid a misdiagnosis of cystadenocarcinoma or low-grade salivary duct carcinoma. Cystadenomas join the list of salivary gland lesions with microscopic similarities to primary lesions of the breast.

Mode structure and continuum damping of high-n toroidal Alfven eigenmodes

International Nuclear Information System (INIS)

Rosenbluth, M.N.; Berk, H.L.; Van Dam, J.W.; Lindberg, D.M.

1992-02-01

An asymptotic theory is described for calculating the mode structure and continuum damping of short wave-length toroidal Alfven eigenmodes (TAE). The formalism somewhat resembles the treatment used for describing low-frequency toroidal modes with singular structure at a rational surface, where an inner solution, which for the TAE mode has toroidal coupling, is matched to an outer toroidally uncoupled solution. A three-term recursion relation among coupled poloidal harmonic amplitudes is obtained, whose solution gives the structure of the global wavefunction and the complex eigenfrequency, including continuum damping. Both analytic and numerical solutions are presented. The magnitude of the damping is essential for determining the thresholds for instability driven by the spatial gradients of energetic particles (e.g., neutral beam-injected ions or fusion-product alpha particles) contained in a tokamak plasma

Electron Scale Structures and Magnetic Reconnection Signatures in the Turbulent Magnetosheath

Science.gov (United States)

Yordanova, E.; Voros, Z.; Varsani, A.; Graham, D. B.; Norgren, C.; Khotyaintsev, Yu. V.; Vaivads, A.; Eriksson, E.; Nakamura, R.; Lindqvist, P.-A.;

Structure and Biological Activity of Pathogen-like Synthetic Nanomedicines

Science.gov (United States)

Lőrincz, Orsolya; Tőke, Enikő R.; Somogyi, Eszter; Horkay, Ferenc; Chandran, Preethi; Douglas, Jack F.; Szebeni, János; Lisziewicz, Julianna

2011-01-01

Here we characterize the structure, stability and intracellular mode-of-action of DermaVir nanomedicine that is under clinical development for the treatment of HIV/AIDS. This nanomedicine is comprised of pathogen-like pDNA/PEIm nanoparticles (NPs) having the structure and function resembling spherical viruses that naturally evolved to deliver nucleic acids to the cells. Atomic force microscopy demonstrated spherical 100–200nm NPs with a smooth polymer surface protecting the pDNA in the core. Optical-absorption determined both the NP structural stability and biological activity relevant to their ability to escape from the endosome and release the pDNA at the nucleus. Salt, pH and temperature influence the nanomedicine shelf-life and intracellular stability. This approach facilitates the development of diverse polyplex nanomedicines where the delivered pDNA-expressed antigens induce immune responses to kill infected cells. PMID:21839051

Experiences and results from Elkraft 1 MW wind turbine

Energy Technology Data Exchange (ETDEWEB)

Raben, N; Jensen, F V [SEAS Distribution A.m.b.A., Wind Power Dept., Haslev (Denmark); Oeye, S [DTU, Inst. for Energiteknik, Lyngby (Denmark); Markkilde Petersen, S; Antoniou, I [Risoe National Lab., Wind Energy and Atmospheric Physics Dept., Roskilde (Denmark)

1999-03-01

The Elkraft 1 MW Demonstration wind turbine was at the time of installation in 1993 the largest stall controlled wind turbine in the world. It was constructed to allow accurate comparison of two different forms of operation: pitch control and stall control. A comprehensive programme for the investigation of the two operation modes was established. This paper presents the main experiences from five years of operation and measurements. For a three-year period the wind turbine was in operation in stall controlled mode. During this period the turbine faced problems of various significance. Especially lightning strikes and unusually poor wind conditions caused delays of the project. In early 1997, the wind turbine was modified to enable pitch controlled operation. The gearbox ratio was changed in order to allow higher rotor speed, the hydraulic system was altered and new control software was installed. Tests were carried out successfully during the spring of 1997 and the wind turbine has since been operating as a pitch controlled wind turbine. The most significant events and problems are presented and commented in this paper along with results from the measurement programme. The results cover both stall and pitch controlled operation and include power curves, annual energy production, structural loads, fatigue loads etc. (au) 10 refs.

Hydrodynamic characteristics for flow around wavy wings with different wave lengths

Directory of Open Access Journals (Sweden)

Mi Jeong Kim

2012-12-01

Full Text Available The present study numerically investigates the effect of the wavy leading edge on hydrodynamic characteristics for the flow of rectangular wings with the low aspect ratio of 1.5. Five different wave lengths at fixed wavy amplitude have been considered. Numerical simulations are performed at a wide range of the angle of attack (0° ≤α ≤ 40° at one Reynolds number of 106. The wavy wings considered in this study did not experience enough lift drop to be defined as the stall, comparing with the smooth wing. However, in the pre-stall region, the wavy wings reveal the considerable loss of the lift, compared to the smooth wing. In the post-stall, the lift coefficients of the smooth wing and the wavy wings are not much different. The pressure coefficient, limiting streamlines and the iso-surface of the spanwise vorticity are also highlighted to examine the effect of the wave length on the flow structures.

Molecular basis for PrimPol recruitment to replication forks by RPA.

Science.gov (United States)

Guilliam, Thomas A; Brissett, Nigel C; Ehlinger, Aaron; Keen, Benjamin A; Kolesar, Peter; Taylor, Elaine M; Bailey, Laura J; Lindsay, Howard D; Chazin, Walter J; Doherty, Aidan J

2017-05-23

DNA damage and secondary structures can stall the replication machinery. Cells possess numerous tolerance mechanisms to complete genome duplication in the presence of such impediments. In addition to translesion synthesis (TLS) polymerases, most eukaryotic cells contain a multifunctional replicative enzyme called primase-polymerase (PrimPol) that is capable of directly bypassing DNA damage by TLS, as well as repriming replication downstream of impediments. Here, we report that PrimPol is recruited to reprime through its interaction with RPA. Using biophysical and crystallographic approaches, we identify that PrimPol possesses two RPA-binding motifs and ascertained the key residues required for these interactions. We demonstrate that one of these motifs is critical for PrimPol's recruitment to stalled replication forks in vivo. In addition, biochemical analysis reveals that RPA serves to stimulate the primase activity of PrimPol. Together, these findings provide significant molecular insights into PrimPol's mode of recruitment to stalled forks to facilitate repriming and restart.

Hydroxyurea-Mediated Cytotoxicity Without Inhibition of Ribonucleotide Reductase.

Science.gov (United States)

Liew, Li Phing; Lim, Zun Yi; Cohen, Matan; Kong, Ziqing; Marjavaara, Lisette; Chabes, Andrei; Bell, Stephen D

2016-11-01

In many organisms, hydroxyurea (HU) inhibits class I ribonucleotide reductase, leading to lowered cellular pools of deoxyribonucleoside triphosphates. The reduced levels for DNA precursors is believed to cause replication fork stalling. Upon treatment of the hyperthermophilic archaeon Sulfolobus solfataricus with HU, we observe dose-dependent cell cycle arrest, accumulation of DNA double-strand breaks, stalled replication forks, and elevated levels of recombination structures. However, Sulfolobus has a HU-insensitive class II ribonucleotide reductase, and we reveal that HU treatment does not significantly impact cellular DNA precursor pools. Profiling of protein and transcript levels reveals modulation of a specific subset of replication initiation and cell division genes. Notably, the selective loss of the regulatory subunit of the primase correlates with cessation of replication initiation and stalling of replication forks. Furthermore, we find evidence for a detoxification response induced by HU treatment. Copyright © 2016 The Author(s). Published by Elsevier Inc. All rights reserved.

Novel animal defenses against predation: a snail egg neurotoxin combining lectin and pore-forming chains that resembles plant defense and bacteria attack toxins.

Directory of Open Access Journals (Sweden)

Marcos Sebastián Dreon

Full Text Available Although most eggs are intensely predated, the aerial egg clutches from the aquatic snail Pomacea canaliculata have only one reported predator due to unparalleled biochemical defenses. These include two storage-proteins: ovorubin that provides a conspicuous (presumably warning coloration and has antinutritive and antidigestive properties, and PcPV2 a neurotoxin with lethal effect on rodents. We sequenced PcPV2 and studied whether it was able to withstand the gastrointestinal environment and reach circulation of a potential predator. Capacity to resist digestion was assayed using small-angle X-ray scattering (SAXS, fluorescence spectroscopy and simulated gastrointestinal proteolysis. PcPV2 oligomer is antinutritive, withstanding proteinase digestion and displaying structural stability between pH 4.0-10.0. cDNA sequencing and protein domain search showed that its two subunits share homology with membrane attack complex/perforin (MACPF-like toxins and tachylectin-like lectins, a previously unknown structure that resembles plant Type-2 ribosome-inactivating proteins and bacterial botulinum toxins. The protomer has therefore a novel AB toxin combination of a MACPF-like chain linked by disulfide bonds to a lectin-like chain, indicating a delivery system for the former. This was further supported by observing PcPV2 binding to glycocalix of enterocytes in vivo and in culture, and by its hemaggutinating, but not hemolytic activity, which suggested an interaction with surface oligosaccharides. PcPV2 is able to get into predator's body as evidenced in rats and mice by the presence of circulating antibodies in response to sublethal oral doses. To our knowledge, a lectin-pore-forming toxin has not been reported before, providing the first evidence of a neurotoxic lectin in animals, and a novel function for ancient and widely distributed proteins. The acquisition of this unique neurotoxic/antinutritive/storage protein may confer the eggs a survival advantage

ZOMG - III. The effect of halo assembly on the satellite population

Science.gov (United States)

Garaldi, Enrico; Romano-Díaz, Emilio; Borzyszkowski, Mikolaj; Porciani, Cristiano

2018-01-01

We use zoom hydrodynamical simulations to investigate the properties of satellites within galaxy-sized dark-matter haloes with different assembly histories. We consider two classes of haloes at redshift z = 0: 'stalled' haloes that assembled at z > 1 and 'accreting' ones that are still forming nowadays. Previously, we showed that the stalled haloes are embedded within thick filaments of the cosmic web, while the accreting ones lie where multiple thin filaments converge. We find that satellites in the two classes have both similar and different properties. Their mass spectra, radial count profiles, baryonic and stellar content, and the amount of material they shed are indistinguishable. However, the mass fraction locked in satellites is substantially larger for the accreting haloes as they experience more mergers at late times. The largest difference is found in the satellite kinematics. Substructures fall towards the accreting haloes along quasi-radial trajectories whereas an important tangential velocity component is developed, before accretion, while orbiting the filament that surrounds the stalled haloes. Thus, the velocity anisotropy parameter of the satellites (β) is positive for the accreting haloes and negative for the stalled ones. This signature enables us to tentatively categorize the Milky Way halo as stalled based on a recent measurement of β. Half of our haloes contain clusters of satellites with aligned orbital angular momenta corresponding to flattened structures in space. These features are not driven by baryonic physics and are only found in haloes hosting grand-design spiral galaxies, independently of their assembly history.

Meurigite, a new fibrous iron phosphate resembling kidwellite

Science.gov (United States)

Birch, W.D.; Pring, A.; Self, P.G.; Gibbs, R.B.; Keck, E.; Jensen, M.C.; Foord, E.E.

1996-01-01

Meurigite is a new hydrated potassium iron phosphate related to kidwellite and with structural similarities to other late-stage fibrous ferric phosphate species. It has been found at four localities so far - the Santa Rita mine, New Mexico, U.S.A.; the Hagendorf-Sud pegmatite in Bavaria, Germany; granite pegmatite veins at Wycheproof, Victoria. Australia; and at the Gold Quarry Mine, Nevada, U.S.A. The Santa Rita mine is the designated type locality. Meurigite occurs as tabular, elongated crystals forming spherical and hemispherical clusters and drusy coatings. The colour ranges from creamy white to pale yellow and yellowish brown. At the type locality, the hemispheres may reach 2 mm across, but the maximum diameter reached in the other occurrences is usually less than 0.5 mm. A wide variety of secondary phosphate minerals accompanies meurigite at each locality, with dufrenite, cyrilovite. beraunite, rockbridgeite and leucophosphite amongst the most common. Vanadates and uranates occur with meurigite at the Gold Quarry mine. Electron microprobe analysis and separate determination of H2O and CO2 on meurigite from the type locality gave a composition for which several empirical formulae could be calculated. The preferred formula, obtained on the basis of 35 oxygen atoms, is (K0.85Na0.03)??0.88(Fe7.013+Al0.16Cu0.02)??7.19 (PO4)5.11(CO3)0.20(OH) 6.7??7-7.25H2O, which simplifies to KFe73+(PO4)5(OH) 7??8H2O. Qualitative analyses only were obtained for meurigite from the other localities, due to the softness and openness of the aggregates. Because of the fibrous nature of meurigite, it was not possible to determine the crystal structure, hence the exact stoichiometry remains uncertain. The lustre of meurigite varies from vitreous to waxy for the Santa Rita mine mineral, to silky for the more open sprays and internal surfaces elsewhere. The streak is very pale yellow to cream and the estimated Mohs hardness is about 3. Cleavage is perfect on {001] and fragments from the

Effects of bedding quality on lying behavior of dairy cows.

Science.gov (United States)

Fregonesi, J A; Veira, D M; von Keyserlingk, M A G; Weary, D M

2007-12-01

Cows prefer to spend more time lying down in free stalls with more bedding, but no research to date has addressed the effects of bedding quality. Bedding in stalls often becomes wet either from exposure to the elements or from feces and urine. The aim of this study was to test the effect of wet bedding on stall preference and use. Four groups of 6 nonlactating Holstein cows were housed in free stalls bedded daily with approximately 0.1 m of fresh sawdust. Following a 5-d adaptation period, each group of cows was tested sequentially with access to stalls with either dry or wet sawdust bedding (86.4 +/- 2.1 vs. 26.5 +/- 2.1% dry matter), each for 2 d. These no-choice phases were followed by a 2-d free-choice phase during which cows had simultaneous access to stalls containing either wet or dry bedding. Stall usage was assessed by using 24-h video recordings scanned at 10-min intervals, and responses were analyzed by using a mixed model, with group (n = 4) as the observational unit. The minimum and maximum environmental temperatures during the experiment were 3.4 +/- 2.2 and 6.8 +/- 2.5 degrees C, respectively. When cows had access only to stalls with wet bedding, they spent 8.8 +/- 0.8 h/d lying down, which increased to 13.8 +/- 0.8 h/d when stalls with dry bedding were provided. Cows spent more time standing with their front 2 hooves in the stall when provided with wet vs. dry bedding (92 +/- 10 vs. 32 +/- 10 min/d). During the free-choice phase, all cows spent more time lying down in the dry stalls, spending 12.5 +/- 0.3 h/d in the dry stalls vs. 0.9 +/- 0.3 h/ d in stalls with wet bedding. In conclusion, dairy cows show a clear preference for a dry lying surface, and they spend much more time standing outside the stall when only wet bedding is available.

Fork stalling and template switching as a mechanism for polyalanine tract expansion affecting the DYC mutant of HOXD13, a new murine model of synpolydactyly.

Science.gov (United States)

Cocquempot, Olivier; Brault, Véronique; Babinet, Charles; Herault, Yann

2009-09-01

Polyalanine expansion diseases are proposed to result from unequal crossover of sister chromatids that increases the number of repeats. In this report we suggest an alternative mechanism we put forward while we investigated a new spontaneous mutant that we named "Dyc" for "Digit in Y and Carpe" phenotype. Phenotypic analysis revealed an abnormal limb patterning similar to that of the human inherited congenital disease synpolydactyly (SPD) and to the mouse mutant model Spdh. Both human SPD and mouse Spdh mutations affect the Hoxd13 gene within a 15-residue polyalanine-encoding repeat in the first exon of the gene, leading to a dominant negative HOXD13. Genetic analysis of the Dyc mutant revealed a trinucleotide expansion in the polyalanine-encoding region of the Hoxd13 gene resulting in a 7-alanine expansion. However, unlike the Spdh mutation, this expansion cannot result from a simple duplication of a short segment. Instead, we propose the fork stalling and template switching (FosTeS) described for generation of nonrecurrent genomic rearrangements as a possible mechanism for the Dyc polyalanine extension, as well as for other polyalanine expansions described in the literature and that could not be explained by unequal crossing over.

Holographic shell model: Stack data structure inside black holes?

Science.gov (United States)

Davidson, Aharon

2014-03-01

Rather than tiling the black hole horizon by Planck area patches, we suggest that bits of information inhabit, universally and holographically, the entire black core interior, a bit per a light sheet unit interval of order Planck area difference. The number of distinguishable (tagged by a binary code) configurations, counted within the context of a discrete holographic shell model, is given by the Catalan series. The area entropy formula is recovered, including Cardy's universal logarithmic correction, and the equipartition of mass per degree of freedom is proven. The black hole information storage resembles, in the count procedure, the so-called stack data structure.

Dimeric structure of the N-terminal domain of PriB protein from Thermoanaerobacter tengcongensis solved ab initio

Energy Technology Data Exchange (ETDEWEB)

Liebschner, Dorothee [National Cancer Institute, Argonne National Laboratory, Argonne, IL 60439 (United States); Brzezinski, Krzysztof [National Cancer Institute, Argonne National Laboratory, Argonne, IL 60439 (United States); University of Bialystok, 15-399 Bialystok (Poland); Dauter, Miroslawa [Argonne National Laboratory, Argonne, IL 60439 (United States); Dauter, Zbigniew, E-mail: dauter@anl.gov [National Cancer Institute, Argonne National Laboratory, Argonne, IL 60439 (United States); Nowak, Marta; Kur, Józef; Olszewski, Marcin, E-mail: dauter@anl.gov [Gdansk University of Technology, 80-952 Gdansk (Poland); National Cancer Institute, Argonne National Laboratory, Argonne, IL 60439 (United States)

2012-12-01

The N-terminal domain of the PriB protein from the thermophilic bacterium T. tengcongensis (TtePriB) was expressed and its crystal structure has been solved at the atomic resolution of 1.09 Å by direct methods. PriB is one of the components of the bacterial primosome, which catalyzes the reactivation of stalled replication forks at sites of DNA damage. The N-terminal domain of the PriB protein from the thermophilic bacterium Thermoanaerobacter tengcongensis (TtePriB) was expressed and its crystal structure was solved at the atomic resolution of 1.09 Å by direct methods. The protein chain, which encompasses the first 104 residues of the full 220-residue protein, adopts the characteristic oligonucleotide/oligosaccharide-binding (OB) structure consisting of a five-stranded β-barrel filled with hydrophobic residues and equipped with four loops extending from the barrel. In the crystal two protomers dimerize, forming a six-stranded antiparallel β-sheet. The structure of the N-terminal OB domain of T. tengcongensis shows significant differences compared with mesophile PriBs. While in all other known structures of PriB a dimer is formed by two identical OB domains in separate chains, TtePriB contains two consecutive OB domains in one chain. However, sequence comparison of both the N-terminal and the C-terminal domains of TtePriB suggests that they have analogous structures and that the natural protein possesses a structure similar to a dimer of two N-terminal domains.

Simulating Dynamic Stall in a 2D VAWT: Modeling strategy, verification and validation with Particle Image Velocimetry data

International Nuclear Information System (INIS)

Ferreira, C J Simao; Bijl, H; Bussel, G van; Kuik, G van

2007-01-01

The implementation of wind energy conversion systems in the built environment renewed the interest and the research on Vertical Axis Wind Turbines (VAWT), which in this application present several advantages over Horizontal Axis Wind Turbines (HAWT). The VAWT has an inherent unsteady aerodynamic behavior due to the variation of angle of attack with the angle of rotation, perceived velocity and consequentially Reynolds number. The phenomenon of dynamic stall is then an intrinsic effect of the operation of a Vertical Axis Wind Turbine at low tip speed ratios, having a significant impact in both loads and power. The complexity of the unsteady aerodynamics of the VAWT makes it extremely attractive to be analyzed using Computational Fluid Dynamics (CFD) models, where an approximation of the continuity and momentum equations of the Navier-Stokes equations set is solved. The complexity of the problem and the need for new design approaches for VAWT for the built environment has driven the authors of this work to focus the research of CFD modeling of VAWT on: .comparing the results between commonly used turbulence models: URANS (Spalart-Allmaras and k-ε) and large eddy models (Large Eddy Simulation and Detached Eddy Simulation) .verifying the sensitivity of the model to its grid refinement (space and time), .evaluating the suitability of using Particle Image Velocimetry (PIV) experimental data for model validation. The 2D model created represents the middle section of a single bladed VAWT with infinite aspect ratio. The model simulates the experimental work of flow field measurement using Particle Image Velocimetry by Simao Ferreira et al for a single bladed VAWT. The results show the suitability of the PIV data for the validation of the model, the need for accurate simulation of the large eddies and the sensitivity of the model to grid refinement

Unsteady Thick Airfoil Aerodynamics: Experiments, Computation, and Theory

Science.gov (United States)

Strangfeld, C.; Rumsey, C. L.; Mueller-Vahl, H.; Greenblatt, D.; Nayeri, C. N.; Paschereit, C. O.

2015-01-01

An experimental, computational and theoretical investigation was carried out to study the aerodynamic loads acting on a relatively thick NACA 0018 airfoil when subjected to pitching and surging, individually and synchronously. Both pre-stall and post-stall angles of attack were considered. Experiments were carried out in a dedicated unsteady wind tunnel, with large surge amplitudes, and airfoil loads were estimated by means of unsteady surface mounted pressure measurements. Theoretical predictions were based on Theodorsen's and Isaacs' results as well as on the relatively recent generalizations of van der Wall. Both two- and three-dimensional computations were performed on structured grids employing unsteady Reynolds-averaged Navier-Stokes (URANS). For pure surging at pre-stall angles of attack, the correspondence between experiments and theory was satisfactory; this served as a validation of Isaacs theory. Discrepancies were traced to dynamic trailing-edge separation, even at low angles of attack. Excellent correspondence was found between experiments and theory for airfoil pitching as well as combined pitching and surging; the latter appears to be the first clear validation of van der Wall's theoretical results. Although qualitatively similar to experiment at low angles of attack, two-dimensional URANS computations yielded notable errors in the unsteady load effects of pitching, surging and their synchronous combination. The main reason is believed to be that the URANS equations do not resolve wake vorticity (explicitly modeled in the theory) or the resulting rolled-up un- steady flow structures because high values of eddy viscosity tend to \\smear" the wake. At post-stall angles, three-dimensional computations illustrated the importance of modeling the tunnel side walls.

Análise do investimento em climatização para bovinos de leite em sistema de alojamento free-stall Analysis of the investment in climatization for dairy cows in freestall

Directory of Open Access Journals (Sweden)

Silvia R. L. Souza

2004-08-01

Full Text Available A dificuldade de adaptação das raças leiteiras européias no Brasil afeta diretamente o setor produtivo de leite. As condições climáticas do País são desfavoráveis, e o desenvolvimento de novas tecnologias é imprescindível para que o potencial genético e a capacidade de conversão alimentar sejam evidenciados nos animais. Dessa forma, a análise econômica do investimento na climatização de instalações do tipo free-stall torna-se necessária para estimar os aspectos relacionados à rentabilidade, capacidade de pagamento e tempo necessário para recuperar o capital investido. O objetivo deste trabalho foi o de avaliar a influência da climatização no processo produtivo de bovinos de leite e realizar uma análise econômica do investimento. Foram utilizadas 470 vacas com características genéticas e morfológicas homogêneas, de alta produção, analisadas em dois períodos semelhantes. Os cálculos do investimento foram efetuados por meio do programa Excell®. Os resultados das análises indicam que deve haver retorno do capital investido em curto prazo (57 dias.The difficulty in adapting European dairy cows breeds in Brazil affect considerably the milk production sector. Brazilian climatic conditions are not totally favorable and the development of new tecnologies is needed for the animals express their genetic potential, as well as their best feed conversion. An economical analysis of the applied investment in the free-stall climatization equipment in dairy housing, for estimating studies related to profit, possibility of return investment as well as time for this return is necessary. The objective of this research was to evaluate the influence of climatization investment in the milk production process and analyze the economical aspect of this investment. There were used 470 high productive dairy cows with genetic and morphologic homogeneous characteristics, and analyzed in two similar periods. Investment calculations were

Anatomy and origin of carbonate structures in a Miocene cold-seep field

Science.gov (United States)

Aiello, Ivano W.; Garrison, Robert E.; Moore, J. Casey; Kastner, Miriam; Stakes, Debra S.

2001-12-01

Miocene calcite concretions resembling modern carbonate structures that form at cold seeps are present in fractured opal- CT porcelanites that are interbedded with mudstones in coastal cliffs at Santa Cruz, California. The morphologies of the carbonate structures differ markedly from conventional concretions and are spatially aligned with orthogonal joints in the porcelanites. The structures contain tubular holes that are identical to fluid and gas conduits in modern carbonate seep structures; the orientations of these tubes suggest that fluid and gas flow was both vertical and horizontal, the latter along extensional joints that formed preferentially in the brittle, silica-rich layers that had enhanced bedding- parallel permeability. Petrographic and isotopic characteristics of the carbonate structures indicate that calcite precipitation occurred in a shallow, subseafloor environment in either the zone of microbial sulfate reduction or of methanogenesis, prior to or possibly simultaneously with the silica phase transformation of opal- A in diatom shells to opal-CT.

Observation of Rayleigh-Taylor-like structures in a laser-accelerated foil

International Nuclear Information System (INIS)

Whitlock, R.R.; Emery, M.H.; Stamper, J.A.; McLean, E.A.; Obenschain, S.P.; Peckerar, M.C.

1984-01-01

Laser-accelerated targets have been predicted to be subject to the Rayleigh-Taylor hydrodynamic instability. The development of the instability was studied by introducing mass thickness variations in foil targets and observing the development of the target nonuniformities by side-on flash x radiography. Observations were made of target structures and mass redistribution effects which resemble Rayleigh-Taylor bubbles and spikes, including not only advanced broadening of the spike tips on the laser-irradiated side of the foil but also projections of mass on the unirradiated side. The observations compare well with numerical simulations

Analytical structural optimization and experimental verifications for traveling wave generation in self-assembling swimming smart boxes

International Nuclear Information System (INIS)

Bani-Hani, M A; Karami, M A

2015-01-01

This paper presents vibration analysis and structural optimization of a swimming–morphing structure. The swimming of the structure is achieved by utilization of piezoelectric patches to generate traveling waves. The third mode shape of the structure in the longitudinal direction resembles the body waveform of a swimming eel. After swimming to its destination, the morphing structure changes shape from an open box to a cube using shape memory alloys (SMAs). The SMAs used for the configuration change of the box robot cannot be used for swimming since they fail to operate at high frequencies. Piezoelectric patches are actuated at the third natural frequency of the structure. We optimize the thickness of the panels and the stiffness of the springs at the joints to generate swimming waveforms that most closely resemble the body waveform of an eel. The traveling wave is generated using two piezoelectric sets of patches bonded to the first and last segments of the beams in the longitudinal direction. Excitation of the piezoelectric results in coupled system dynamics equations that can be translated into the generation of waves. Theoretical analysis based on the distributed parameter model is conducted in this paper. A scalar measure of the traveling to standing wave ratio is introduced using a 2-dimensional Fourier transform (2D-FFT) of the body deformation waveform. An optimization algorithm based on tuning the flexural transverse wave is established to obtain a higher traveling to standing wave ratio. The results are then compared to common methods in the literature for assessment of standing to traveling wave ratios. The analytical models are verified by the close agreement between the traveling waves predicted by the model and those measured in the experiments. (paper)

Resolving complex chromosome structures during meiosis: versatile deployment of Smc5/6.

Science.gov (United States)

Verver, Dideke E; Hwang, Grace H; Jordan, Philip W; Hamer, Geert

2016-03-01

The Smc5/6 complex, along with cohesin and condensin, is a member of the structural maintenance of chromosome (SMC) family, large ring-like protein complexes that are essential for chromatin structure and function. Thanks to numerous studies of the mitotic cell cycle, Smc5/6 has been implicated to have roles in homologous recombination, restart of stalled replication forks, maintenance of ribosomal DNA (rDNA) and heterochromatin, telomerase-independent telomere elongation, and regulation of chromosome topology. The nature of these functions implies that the Smc5/6 complex also contributes to the profound chromatin changes, including meiotic recombination, that characterize meiosis. Only recently, studies in diverse model organisms have focused on the potential meiotic roles of the Smc5/6 complex. Indeed, Smc5/6 appears to be essential for meiotic recombination. However, due to both the complexity of the process of meiosis and the versatility of the Smc5/6 complex, many additional meiotic functions have been described. In this review, we provide a clear overview of the multiple functions found so far for the Smc5/6 complex in meiosis. Additionally, we compare these meiotic functions with the known mitotic functions in an attempt to find a common denominator and thereby create clarity in the field of Smc5/6 research.

Monomeric Aβ1–40 and Aβ1–42 Peptides in Solution Adopt Very Similar Ramachandran Map Distributions That Closely Resemble Random Coil

Science.gov (United States)

2016-01-01

The pathogenesis of Alzheimer’s disease is characterized by the aggregation and fibrillation of amyloid peptides Aβ1–40 and Aβ1–42 into amyloid plaques. Despite strong potential therapeutic interest, the structural pathways associated with the conversion of monomeric Aβ peptides into oligomeric species remain largely unknown. In particular, the higher aggregation propensity and associated toxicity of Aβ1–42 compared to that of Aβ1–40 are poorly understood. To explore in detail the structural propensity of the monomeric Aβ1–40 and Aβ1–42 peptides in solution, we recorded a large set of nuclear magnetic resonance (NMR) parameters, including chemical shifts, nuclear Overhauser effects (NOEs), and J couplings. Systematic comparisons show that at neutral pH the Aβ1–40 and Aβ1–42 peptides populate almost indistinguishable coil-like conformations. Nuclear Overhauser effect spectra collected at very high resolution remove assignment ambiguities and show no long-range NOE contacts. Six sets of backbone J couplings (3JHNHα, 3JC′C′, 3JC′Hα, 1JHαCα, 2JNCα, and 1JNCα) recorded for Aβ1–40 were used as input for the recently developed MERA Ramachandran map analysis, yielding residue-specific backbone ϕ/ψ torsion angle distributions that closely resemble random coil distributions, the absence of a significantly elevated propensity for β-conformations in the C-terminal region of the peptide, and a small but distinct propensity for αL at K28. Our results suggest that the self-association of Aβ peptides into toxic oligomers is not driven by elevated propensities of the monomeric species to adopt β-strand-like conformations. Instead, the accelerated disappearance of Aβ NMR signals in D2O over H2O, particularly pronounced for Aβ1–42, suggests that intermolecular interactions between the hydrophobic regions of the peptide dominate the aggregation process. PMID:26780756

Higher-order structure of Saccharomyces cerevisiae chromatin

International Nuclear Information System (INIS)

Lowary, P.T.; Widom, J.

1989-01-01

We have developed a method for partially purifying chromatin from Saccharomyces cerevisiae (baker's yeast) to a level suitable for studies of its higher-order folding. This has required the use of yeast strains that are free of the ubiquitous yeast killer virus. Results from dynamic light scattering, electron microscopy, and x-ray diffraction show that the yeast chromatin undergoes a cation-dependent folding into 30-nm filaments that resemble those characteristic of higher-cell chromatin; moreover, the packing of nucleosomes within the yeast 30-nm filaments is similar to that of higher cells. These results imply that yeast has a protein or protein domain that serves the role of the histone H 1 found in higher cells; physical and genetic studies of the yeast activity could help elucidate the structure and function of H 1. Images of the yeast 30-nm filaments can be used to test crossed-linker models for 30-nm filament structure

STUDY ON THE SYNTHESIS AND STRUCTURE OF MACRORETICULAR BEAD PAN/PVC IPN RESINS

Institute of Scientific and Technical Information of China (English)

LI Yanfeng; ZHUO Renxi

1993-01-01

Macroreticular bead PAN/PVC IPN reans with cyano and chloro groups were synthesized by interpenetrating polymerization of acrylonitrile, or acrylonitrile and divinylbenzene into a macroporous polyvinyl chloride bead. The composition and structure of the bead IPN resins have been investigated by means of FT-IR, NMR, SEM, mercury porosimetry and elemental analysis. During the process of interpenetrating polymerization, the chain propagation obeys Bernoullian statistical law, and no grafting polymerization has been observed. The content of cyano group in the resulting IPN resins can be adjusted by the amount of acrylonitrile added. The morphology of the IPN resins basically resembles that of the polyvinyl chloride bead,whereas the pore structures vary to a certain degree

A triclinic crystal structure of the carboxy-terminal domain of HIV-1 capsid protein with four molecules in the asymmetric unit reveals a novel packing interface

International Nuclear Information System (INIS)

Lampel, Ayala; Yaniv, Oren; Berger, Or; Bacharach, Eran; Gazit, Ehud; Frolow, Felix

2013-01-01

The triclinic structure of the HIV-1 capsid protein contains four molecules in the asymmetric unit that form a novel packing interface that could conceivably resemble an intermediate structure that is involved in the early steps of HIV-1 assembly. The Gag precursor is the major structural protein of the virion of human immunodeficiency virus-1 (HIV-1). Capsid protein (CA), a cleavage product of Gag, plays an essential role in virus assembly both in Gag-precursor multimerization and in capsid core formation. The carboxy-terminal domain (CTD) of CA contains 20 residues that are highly conserved across retroviruses and constitute the major homology region (MHR). Genetic evidence implies a role for the MHR in interactions between Gag precursors during the assembly of the virus, but the structural basis for this role remains elusive. This paper describes a novel triclinic structure of the HIV-1 CA CTD at 1.6 Å resolution with two canonical dimers of CA CTD in the asymmetric unit. The canonical dimers form a newly identified packing interface where interactions of four conserved MHR residues take place. This is the first structural indication that these MHR residues participate in the putative CTD–CTD interactions. These findings suggest that the molecules forming this novel interface resemble an intermediate structure that participates in the early steps of HIV-1 assembly. This interface may therefore provide a novel target for antiviral drugs

In vitro and in silico characterization of open-cell structures of trabecular bone.

Science.gov (United States)

Ramos-Infante, S J; Pérez, M A

2017-11-01

This work aimed to perform a detailed in vitro and in silico characterization of open-cell structures, which resemble trabecular bone, to elucidate osteoporosis failure mechanisms. Experimental and image-based computational methods were used to estimate Young's modulus and porosities of different open-cell structures (Sawbones; Malmö, Sweden). Three different open-cell structures with different porosities were characterized. Additionally, some open-cell structures were scanned using a microcomputed tomography system (μCT) to non-destructively predict specimen Young's modulus of the structures by developing voxel-based and tetrahedral finite element (FE) models. A 3D reconstruction and FE analyses were used. The experimental and computational results with different element types (linear and quadratic tetrahedrons and voxel-based meshes) were compared with Sawbones data (Sawbones; Malmö, Sweden) revealing important differences in Young's modulus and porosities. The specimens with high and low volume fractions were best represented by linear and quadratic tetrahedrons, respectively. These results could be used to develop new osteoporosis-prevention strategies.

Experimental study of pitching and plunging airfoils at low Reynolds numbers

Energy Technology Data Exchange (ETDEWEB)

Baik, Yeon Sik; Bernal, Luis P. [University of Michigan, Department of Aerospace Engineering, Ann Arbor, MI (United States)

2012-12-15

Measurements of the unsteady flow structure and force time history of pitching and plunging SD7003 and flat plate airfoils at low Reynolds numbers are presented. The airfoils were pitched and plunged in the effective angle of attack range of 2.4 -13.6 (shallow-stall kinematics) and -6 to 22 (deep-stall kinematics). The shallow-stall kinematics results for the SD7003 airfoil show attached flow and laminar-to-turbulent transition at low effective angle of attack during the down stroke motion, while the flat plate model exhibits leading edge separation. Strong Re-number effects were found for the SD7003 airfoil which produced approximately 25 % increase in the peak lift coefficient at Re = 10,000 compared to higher Re flows. The flat plate airfoil showed reduced Re effects due to leading edge separation at the sharper leading edge, and the measured peak lift coefficient was higher than that predicted by unsteady potential flow theory. The deep-stall kinematics resulted in leading edge separation that led to formation of a large leading edge vortex (LEV) and a small trailing edge vortex (TEV) for both airfoils. The measured peak lift coefficient was significantly higher ({proportional_to}50 %) than that for the shallow-stall kinematics. The effect of airfoil shape on lift force was greater than the Re effect. Turbulence statistics were measured as a function of phase using ensemble averages. The results show anisotropic turbulence for the LEV and isotropic turbulence for the TEV. Comparison of unsteady potential flow theory with the experimental data showed better agreement by using the quasi-steady approximation, or setting C(k) = 1 in Theodorsen theory, for leading edge-separated flows. (orig.)

Structure of the cold-shock domain protein from Neisseria meningitidis reveals a strand-exchanged dimer

Energy Technology Data Exchange (ETDEWEB)

Ren, Jingshan [The Oxford Protein Production Facility, Henry Wellcome Building for Genomic Medicine, University of Oxford, Roosevelt Drive, Oxford OX3 7BN (United Kingdom); Division of Structural Biology, Henry Wellcome Building for Genomic Medicine, University of Oxford, Roosevelt Drive, Oxford OX3 7BN (United Kingdom); Nettleship, Joanne E.; Sainsbury, Sarah [The Oxford Protein Production Facility, Henry Wellcome Building for Genomic Medicine, University of Oxford, Roosevelt Drive, Oxford OX3 7BN (United Kingdom); Saunders, Nigel J. [Bacterial Pathogenesis and Functional Genomics Group, Sir William Dunn School of Pathology, University of Oxford, South Parks Road, Oxford OX1 3RE (United Kingdom); Owens, Raymond J., E-mail: ray@strubi.ox.ac.uk [The Oxford Protein Production Facility, Henry Wellcome Building for Genomic Medicine, University of Oxford, Roosevelt Drive, Oxford OX3 7BN (United Kingdom)

2008-04-01

The X-ray crystal structure of the cold-shock domain protein from N. meningitidis reveals a strand-exchanged dimer. The structure of the cold-shock domain protein from Neisseria meningitidis has been solved to 2.6 Å resolution and shown to comprise a dimer formed by the exchange of two β-strands between protein monomers. The overall fold of the monomer closely resembles those of other bacterial cold-shock proteins. The neisserial protein behaved as a monomer in solution and was shown to bind to a hexathymidine oligonucleotide with a stoichiometry of 1:1 and a K{sub d} of 1.25 µM.

Three-dimensional structure of the γ-secretase complex

International Nuclear Information System (INIS)

Ogura, Toshihiko; Mio, Kazuhiro; Hayashi, Ikuo; Miyashita, Hiroyuki; Fukuda, Rie; Kopan, Raphael; Kodama, Tatsuhiko; Hamakubo, Takao; Iwastubo, Takeshi; Tomita, Taisuke; Sato, Chikara

2006-01-01

γ-Secretase belongs to an atypical class of aspartic proteases that hydrolyzes peptide bonds within the transmembrane domain of substrates, including amyloid-β precursor protein and Notch. γ-Secretase is comprised of presenilin, nicastrin, APH-1, and PEN-2 which form a large multimeric membrane protein complex, the three-dimensional structure of which is unknown. To gain insight into the structure of this complex enzyme, we purified functional γ-secretase complex reconstituted in Sf9 cells and analyzed it using negative stain electron microscopy and 3D reconstruction techniques. Analysis of 2341 negatively stained particle images resulted in the three-dimensional representation of γ-secretase at a resolution of 48 A. The structure occupies a volume of 560 x 320 x 240 A and resembles a flat heart comprised of two oppositely faced, dimpled domains. A low density space containing multiple pores resides between the domains. Some of the dimples in the putative transmembrane region may house the catalytic site. The large dimensions are consistent with the observation that γ-secretase activity resides within a high molecular weight complex

Structure of Penaeus stylirostris Densovirus, a Shrimp Pathogen

Energy Technology Data Exchange (ETDEWEB)

Kaufmann, Bärbel; Bowman, Valorie D.; Li, Yi; Szelei, Jozsef; Waddell, Peter J.; Tijssen, Peter; Rossmann, Michael G. (INRS); (Purdue)

2010-11-16

Penaeus stylirostris densovirus (PstDNV), a pathogen of penaeid shrimp, causes significant damage to farmed and wild shrimp populations. In contrast to other parvoviruses, PstDNV probably has only one type of capsid protein that lacks the phospholipase A2 activity that has been implicated as a requirement during parvoviral host cell infection. The structure of recombinant virus-like particles, composed of 60 copies of the 37.5-kDa coat protein, the smallest parvoviral capsid protein reported thus far, was determined to 2.5-{angstrom} resolution by X-ray crystallography. The structure represents the first near-atomic resolution structure within the genus Brevidensovirus. The capsid protein has a {beta}-barrel 'jelly roll' motif similar to that found in many icosahedral viruses, including other parvoviruses. The N-terminal portion of the PstDNV coat protein adopts a 'domain-swapped' conformation relative to its twofold-related neighbor similar to the insect parvovirus Galleria mellonella densovirus (GmDNV) but in stark contrast to vertebrate parvoviruses. However, most of the surface loops have little structural resemblance to any of the known parvoviral capsid proteins.

Structure and elevator mechanism of the Na+-citrate transporter CitS.

Science.gov (United States)

Lolkema, Juke S; Slotboom, Dirk Jan

2017-08-01

The recently determined crystal structure of the bacterial Na + -citrate symporter CitS provides unexpected structural and mechanistic insights. The protein has a fold that has not been seen in other proteins, but the oligomeric state, domain organization and proposed transport mechanism strongly resemble those of the sodium-dicarboxylate symporter vcINDY, and the putative exporters YdaH and MtrF, thus hinting at convergence in structure and function. CitS and the related proteins are predicted to translocate their substrates by an elevator-like mechanism, in which a compact transport domain slides up and down through the membrane while the dimerization domain is stably anchored. Here we review the large body of available biochemical data on CitS in the light of the new crystal structure. We show that the biochemical data are fully consistent with the proposed elevator mechanism, but also demonstrate that the current structural data cannot explain how strict coupling of citrate and Na + transport is achieved. We propose a testable model for the coupling mechanism. Copyright © 2016 Elsevier Ltd. All rights reserved.

Crystal structure of secretory protein Hcp3 from Pseudomonas aeruginosa.

Science.gov (United States)

Osipiuk, Jerzy; Xu, Xiaohui; Cui, Hong; Savchenko, Alexei; Edwards, Aled; Joachimiak, Andrzej

2011-03-01

The Type VI secretion pathway transports proteins across the cell envelope of Gram-negative bacteria. Pseudomonas aeruginosa, an opportunistic Gram-negative bacterial pathogen infecting humans, uses the type VI secretion pathway to export specific effector proteins crucial for its pathogenesis. The HSI-I virulence locus encodes for several proteins that has been proposed to participate in protein transport including the Hcp1 protein, which forms hexameric rings that assemble into nanotubes in vitro. Two Hcp1 paralogues have been identified in the P. aeruginosa genome, Hsp2 and Hcp3. Here, we present the structure of the Hcp3 protein from P. aeruginosa. The overall structure of the monomer resembles Hcp1 despite the lack of amino-acid sequence similarity between the two proteins. The monomers assemble into hexamers similar to Hcp1. However, instead of forming nanotubes in head-to-tail mode like Hcp1, Hcp3 stacks its rings in head-to-head mode forming double-ring structures.

Origin and evolution of the deep thermochemical structure beneath Eurasia.

Science.gov (United States)

Flament, N; Williams, S; Müller, R D; Gurnis, M; Bower, D J

2017-01-18

A unique structure in the Earth's lowermost mantle, the Perm Anomaly, was recently identified beneath Eurasia. It seismologically resembles the large low-shear velocity provinces (LLSVPs) under Africa and the Pacific, but is much smaller. This challenges the current understanding of the evolution of the plate-mantle system in which plumes rise from the edges of the two LLSVPs, spatially fixed in time. New models of mantle flow over the last 230 million years reproduce the present-day structure of the lower mantle, and show a Perm-like anomaly. The anomaly formed in isolation within a closed subduction network ∼22,000 km in circumference prior to 150 million years ago before migrating ∼1,500 km westward at an average rate of 1 cm year -1 , indicating a greater mobility of deep mantle structures than previously recognized. We hypothesize that the mobile Perm Anomaly could be linked to the Emeishan volcanics, in contrast to the previously proposed Siberian Traps.

Formation of beads-on-a-string structures during the pinch-off of viscoelastic filaments

Science.gov (United States)

Bhat, Pradeep; Appathurai, Santosh; Harris, Michael; Pasquali, Matteo; McKinley, Gareth; Basaran, Osman

2009-11-01

Breakup of liquid filaments is omnipresent in nature and technology. When a filament formed by placing a drop of syrup between a thumb and a forefinger is stretched by pulling apart the two fingers, it resembles a thinning cylinder. If the same experiment is repeated with saliva, the filament's morphology close to pinch-off resembles that of beads of several sizes interconnected by slender threads. Although there is general agreement that formation of such beads-on-a-string (BOAS) morphology only occurs for viscoelastic fluids, the mechanism behind this phenomenon remains unclear and controversial. The physics of formation of BOAS structures is probed here by simulation which reveals that viscoelasticity alone does not give rise to a small, satellite bead between two much larger main drops (beads) but that inertia is required for its formation. Viscoelasticity, however, enhances the growth of the satellite bead and delays pinch-off, which leads to a relatively long-lived, stable beaded filament. The new simulations also show the formation of second-generation sub-satellite beads in certain cases, as observed experimentally but not, heretofore, predicted theoretically.

Influence of farming system and production purpose on the morpho structure of Spanish goat breeds

Energy Technology Data Exchange (ETDEWEB)

Gonzalez-Martinez, A.; Herrera, M.; Luque, M.; Rodero, E.

2014-06-01

The aim of this study was to examine the possible influence of farming systems, based on the morpho structure of 1,571 female goats drawn from 40 flocks containing seven Spanish breeds (Blanca Andaluza, Blanca Celtiberica, Negra Serrana, Pirenaica, Payoya, Murciano-Granadina and Malaguena) raised under four different farming systems. Analysis of morphometric variables showed that the morphostructure of native Spanish goat breeds was linked to the farming system used and thus to the production purpose. The morphostructure of grazing breeds may be more influenced by natural selection within the physical environment and less by human selection. That of stall-fed breeds, by contrast, reflects intense artificial selection aimed at achieving a highly-productive dairy type. For this reason, morphological evaluation systems used in breeding programmes for meat or dual-purpose goat breeds farmed extensively or semiextensively should be specific, and should reflect the influence of the environment in which these goats are farmed. (Author)

Codon usage regulates protein structure and function by affecting translation elongation speed in Drosophila cells.

Science.gov (United States)

Zhao, Fangzhou; Yu, Chien-Hung; Liu, Yi

2017-08-21

Codon usage biases are found in all eukaryotic and prokaryotic genomes and have been proposed to regulate different aspects of translation process. Codon optimality has been shown to regulate translation elongation speed in fungal systems, but its effect on translation elongation speed in animal systems is not clear. In this study, we used a Drosophila cell-free translation system to directly compare the velocity of mRNA translation elongation. Our results demonstrate that optimal synonymous codons speed up translation elongation while non-optimal codons slow down translation. In addition, codon usage regulates ribosome movement and stalling on mRNA during translation. Finally, we show that codon usage affects protein structure and function in vitro and in Drosophila cells. Together, these results suggest that the effect of codon usage on translation elongation speed is a conserved mechanism from fungi to animals that can affect protein folding in eukaryotic organisms. © The Author(s) 2017. Published by Oxford University Press on behalf of Nucleic Acids Research.

The effects of two out-wintering pad systems compared with free-stalls on dairy cow hoof and limb health.

Science.gov (United States)

O'Driscoll, Keelin Km; Hanlon, Alison; French, Padraig; Boyle, Laura A

2009-02-01

Lameness is one of the most serious health and welfare problems for dairy cows. This study compared hoof health, limb health and locomotion of dairy cows in three over-winter management systems. Treatments were: (1) an indoor free-stall system (FS), (2) outdoors on an uncovered woodchip pad (UP) and (3) outdoors on a covered woodchip pad (CP). Animals were assigned to treatments at drying off, remained on treatment until parturition, then turned out to pasture. Sole lesions were scored on assignment to treatment, at calving, and 6 weeks and 12 weeks post partum. Locomotion and skin lesions were scored on assignment to treatment, and every 2 weeks until parturition. Post-partum locomotion was scored weekly for 13 weeks. More FS cows were affected by limb lesions than CP cows, and these animals had the worst locomotion scores post calving. There was an effect of inspection, and interactive effect of inspection and treatment on sole lesion scores. UP cows had the highest sole lesion scores 12 weeks post partum probably due to softening of the hooves arising from exposure to moisture while on the woodchip pad. However, post partum, UP cows had better locomotion scores, and CP cows tended to have better scores than cows in FS. Both of these treatments were less likely to have a high tracking-up score than cows in FS. It is possible that cows in this treatment were able to exercise more, owing to the secure underfoot surface and lack of barriers, and this promoted limb flexibility. Although woodchip pads provided benefits for limb health and locomotion, the wood chip surface in both outdoor systems did not offer protective benefits to the hooves relative to housing on concrete. However, the provision of shelter on the pad somewhat overcame the problem of high sole lesion scores in the post-partum period.

The effects of bilingualism on the white matter structure of the brain.

Science.gov (United States)

Pliatsikas, Christos; Moschopoulou, Elisavet; Saddy, James Douglas

2015-02-03

Recent studies suggest that learning and using a second language (L2) can affect brain structure, including the structure of white matter (WM) tracts. This observation comes from research looking at early and older bilingual individuals who have been using both their first and second languages on an everyday basis for many years. This study investigated whether young, highly immersed late bilinguals would also show structural effects in the WM that can be attributed to everyday L2 use, irrespective of critical periods or the length of L2 learning. Our Tract-Based Spatial Statistics analysis revealed higher fractional anisotropy values for bilinguals vs. monolinguals in several WM tracts that have been linked to language processing and in a pattern closely resembling the results reported for older and early bilinguals. We propose that learning and actively using an L2 after childhood can have rapid dynamic effects on WM structure, which in turn may assist in preserving WM integrity in older age.

Nuclear insulin-like growth factor 1 receptor phosphorylates proliferating cell nuclear antigen and rescues stalled replication forks after DNA damage.

Science.gov (United States)

Waraky, Ahmed; Lin, Yingbo; Warsito, Dudi; Haglund, Felix; Aleem, Eiman; Larsson, Olle

2017-11-03

We have previously shown that the insulin-like growth factor 1 receptor (IGF-1R) translocates to the cell nucleus, where it binds to enhancer-like regions and increases gene transcription. Further studies have demonstrated that nuclear IGF-1R (nIGF-1R) physically and functionally interacts with some nuclear proteins, i.e. the lymphoid enhancer-binding factor 1 (Lef1), histone H3, and Brahma-related gene-1 proteins. In this study, we identified the proliferating cell nuclear antigen (PCNA) as a nIGF-1R-binding partner. PCNA is a pivotal component of the replication fork machinery and a main regulator of the DNA damage tolerance (DDT) pathway. We found that IGF-1R interacts with and phosphorylates PCNA in human embryonic stem cells and other cell lines. In vitro MS analysis of PCNA co-incubated with the IGF-1R kinase indicated tyrosine residues 60, 133, and 250 in PCNA as IGF-1R targets, and PCNA phosphorylation was followed by mono- and polyubiquitination. Co-immunoprecipitation experiments suggested that these ubiquitination events may be mediated by DDT-dependent E2/E3 ligases ( e.g. RAD18 and SHPRH/HLTF). Absence of IGF-1R or mutation of Tyr-60, Tyr-133, or Tyr-250 in PCNA abrogated its ubiquitination. Unlike in cells expressing IGF-1R, externally induced DNA damage in IGF-1R-negative cells caused G 1 cell cycle arrest and S phase fork stalling. Taken together, our results suggest a role of IGF-1R in DDT. © 2017 by The American Society for Biochemistry and Molecular Biology, Inc.

Extending the honey bee venome with the antimicrobial peptide apidaecin and a protein resembling wasp antigen 5.

Science.gov (United States)

Van Vaerenbergh, M; Cardoen, D; Formesyn, E M; Brunain, M; Van Driessche, G; Blank, S; Spillner, E; Verleyen, P; Wenseleers, T; Schoofs, L; Devreese, B; de Graaf, D C

2013-04-01

Honey bee venom is a complex mixture of toxic proteins and peptides. In the present study we tried to extend our knowledge of the venom composition using two different approaches. First, worker venom was analysed by liquid chromatography-mass spectrometry and this revealed the antimicrobial peptide apidaecin for the first time in such samples. Its expression in the venom gland was confirmed by reverse transcription PCR and by a peptidomic analysis of the venom apparatus tissue. Second, genome mining revealed a list of proteins with resemblance to known insect allergens or venom toxins, one of which showed homology to proteins of the antigen 5 (Ag5)/Sol i 3 cluster. It was demonstrated that the honey bee Ag5-like gene is expressed by venom gland tissue of winter bees but not of summer bees. Besides this seasonal variation, it shows an interesting spatial expression pattern with additional production in the hypopharyngeal glands, the brains and the midgut. Finally, our immunoblot study revealed that both synthetic apidaecin and the Ag5-like recombinant from bacteria evoke no humoral activity in beekeepers. Also, no IgG4-based cross-reactivity was detected between the honey bee Ag5-like protein and its yellow jacket paralogue Ves v 5. © 2013 Royal Entomological Society.

Human FAN1 promotes strand incision in 5'-flapped DNA complexed with RPA.

Science.gov (United States)

Takahashi, Daisuke; Sato, Koichi; Hirayama, Emiko; Takata, Minoru; Kurumizaka, Hitoshi

2015-09-01

Fanconi anaemia (FA) is a human infantile recessive disorder. Seventeen FA causal proteins cooperatively function in the DNA interstrand crosslink (ICL) repair pathway. Dual DNA strand incisions around the crosslink are critical steps in ICL repair. FA-associated nuclease 1 (FAN1) is a DNA structure-specific endonuclease that is considered to be involved in DNA incision at the stalled replication fork. Replication protein A (RPA) rapidly assembles on the single-stranded DNA region of the stalled fork. However, the effect of RPA on the FAN1-mediated DNA incision has not been determined. In this study, we purified human FAN1, as a bacterially expressed recombinant protein. FAN1 exhibited robust endonuclease activity with 5'-flapped DNA, which is formed at the stalled replication fork. We found that FAN1 efficiently promoted DNA incision at the proper site of RPA-coated 5'-flapped DNA. Therefore, FAN1 possesses the ability to promote the ICL repair of 5'-flapped DNA covered by RPA. © The Authors 2015. Published by Oxford University Press on behalf of the Japanese Biochemical Society. All rights reserved.

A naturally derived gastric cancer cell line shows latency I Epstein-Barr virus infection closely resembling EBV-associated gastric cancer

International Nuclear Information System (INIS)

Oh, Sang Taek; Seo, Jung Seon; Moon, Uk Yeol; Kang, Kyeong Hee; Shin, Dong-Jik; Yoon, Sungjoo Kim; Kim, Woo Ho; Park, Jae-Gahb; Lee, Suk Kyeong

2004-01-01

In a process seeking out a good model cell line for Epstein-Barr virus (EBV)-associated gastric cancer, we found that one previously established gastric adenocarcinoma cell line is infected with type 1 EBV. This SNU-719 cell line from a Korean patient expressed cytokeratin without CD19 or CD21 expression. In SNU-719, EBNA1 and LMP2A were expressed, while LMP1 and EBNA2 were not. None of the tested lytic EBV proteins were detected in this cell line unless stimulated with phorbol ester. EBV infection was also shown in the original carcinoma tissue of SNU-719 cell line. Our results support the possibility of a CD21-independent EBV infection of gastric epithelial cells in vivo. As the latent EBV gene expression pattern of SNU-719 closely resembles that of the EBV-associated gastric cancer, this naturally derived cell line may serve as a valuable model system to clarify the precise role of EBV in gastric carcinogenesis

Numerical investigation of the aerodynamic and structural characteristics of a corrugated wing

Science.gov (United States)

Hord, Kyle

Previous experimental studies on static, bio-inspired corrugated wings have shown that they produce favorable aerodynamic properties such as delayed stall compared to streamlined wings and flat plates at high Reynolds numbers (Re ≥ 4x104). The majority of studies have been carried out with scaled models of dragonfly forewings from the Aeshna Cyanea in either wind tunnels or water channels. In this thesis, the aerodynamics of a corrugated airfoil was studied using computational fluid dynamics methods at a low Reynolds number of 1000. Structural analysis was also performed using the commercial software SolidWorks 2009. The flow field is described by solving the incompressible Navier-Stokes equations on an overlapping grid using the pressure-Poisson method. The equations are discretized in space with second-order accurate central differences. Time integration is achieved through the second-order Crank-Nicolson implicit method. The complex vortex structures that form in the corrugated airfoil valleys and around the corrugated airfoil are studied in detail. Comparisons are made with experimental measurements from corrugated wings and also with simulations of a flat plate. Contrary to the studies at high Reynolds numbers, our study shows that at low Reynolds numbers the wing corrugation does not provide any aerodynamic benefit compared to a smoothed flat plate. Instead, the corrugated profile generates more pressure drag which is only partially offset by the reduction of friction drag, leading to more total drag than the flat plate. Structural analysis shows that the wing corrugation can increase the resistance to bending moments on the wing structure. A smoothed structure has to be three times thicker to provide the same stiffness. It was concluded the corrugated wing has the structural benefit to provide the same resistance to bending moments with a much reduced weight.

GARN: Sampling RNA 3D Structure Space with Game Theory and Knowledge-Based Scoring Strategies.

Science.gov (United States)

Boudard, Mélanie; Bernauer, Julie; Barth, Dominique; Cohen, Johanne; Denise, Alain

2015-01-01

Cellular processes involve large numbers of RNA molecules. The functions of these RNA molecules and their binding to molecular machines are highly dependent on their 3D structures. One of the key challenges in RNA structure prediction and modeling is predicting the spatial arrangement of the various structural elements of RNA. As RNA folding is generally hierarchical, methods involving coarse-grained models hold great promise for this purpose. We present here a novel coarse-grained method for sampling, based on game theory and knowledge-based potentials. This strategy, GARN (Game Algorithm for RNa sampling), is often much faster than previously described techniques and generates large sets of solutions closely resembling the native structure. GARN is thus a suitable starting point for the molecular modeling of large RNAs, particularly those with experimental constraints. GARN is available from: http://garn.lri.fr/.

The peptide NDP-MSH induces phenotype changes in the heart that resemble ischemic preconditioning.

Science.gov (United States)

Catania, Anna; Lonati, Caterina; Sordi, Andrea; Leonardi, Patrizia; Carlin, Andrea; Gatti, Stefano

2010-01-01

alpha-Melanocyte-stimulating hormone (alpha-MSH) is a pro-opiomelanocortin (POMC)-derived peptide that exerts multiple protective effects on host cells. Previous investigations showed that treatment with alpha-MSH or synthetic melanocortin agonists reduces heart damage in reperfusion injury and transplantation. The aim of this preclinical research was to determine whether melanocortin treatment induces preconditioning-like cardioprotection. In particular, the plan was to assess whether melanocortin administration causes phenotype changes similar to those induced by repetitive ischemic events. The idea was conceived because both ischemic preconditioning and melanocortin signaling largely depend on cAMP response element binding protein (CREB) phosphorylation. Rats received single i.v. injections of 750microg/kg of the alpha-MSH analogue Nle(4),DPhe(7)-alpha-MSH (NDP-MSH) or saline and were sacrificed at 0.5, 1, 3, or 5h. Western blot analysis showed that rat hearts expressed melanocortin 1 receptor (MC1R) protein. Treatment with NDP-MSH was associated with early and marked increase in interleukin 6 (IL-6) mRNA. This was followed by signal transducer and activator of transcription 3 (STAT3) phosphorylation and induction of suppressor of cytokine signaling 3 (SOCS3). There were no changes in expression of other cytokines of the IL-6 family. Expression of IL-10, IL-1beta, and TNF-alpha was likewise unaltered. In hearts of rats treated with NDP-MSH there was increased expression of the orphan nuclear receptor Nur77. The data indicate that NDP-MSH induces phenotype changes that closely resemble ischemic preconditioning and likely contribute to its established protection against reperfusion injury. In addition, the increased expression of Nur77 and SOCS3 could be part of a broader anti-inflammatory effect.

Structure of zone-cast HBC-C12H25 films

DEFF Research Database (Denmark)

Breiby, Dag Werner; Bunk, Oliver; Pisula, W.

2005-01-01

The structure of a thin zone-cast film of the hexa-n-dodecyl-substituted hexa-peri-benzocoronene (HBC) has been investigated using grazing incidence X-ray diffraction. A model with an orthorhombic unit cell containing two molecules accounts well for the observations. The molecules are arranged...... in a "herringbone" structure resembling the packing observed for unsubstituted HBC. The molecular disk planes are oriented perpendicularly to the substrate, rotated by approximately 39 degrees about the film normal. The relatively long side chains of dodecyl were found to be in an ordered interdigitated state....... The aliphatic side chains and the aromatic HBC-cores segregate to form regular vertical domains spanning the film thickness. For in-plane rocking scans a discrete orientation distribution is observed with peaks at regular angle intervals. We interpret this as a grain boundary effect induced by alkyl chain...

Reliability and Hierarchical Structure of DSM-5 Pathological Traits in a Danish Mixed Sample

DEFF Research Database (Denmark)

Bo, Sune; Bach, Bo; Mortensen, Erik Lykke

2016-01-01

In this study we assessed the DSM-5 trait model in a large Danish sample (n = 1,119) with respect to reliability of the applied Danish version of the Personality Inventory for DSM-5 (PID-5) self-report form by means of internal consistency and item discrimination. In addition, we tested whether...... the five-factor structure of the DSM-5 trait model can be replicated in a Danish independent sample using the PID-5 self-report form. Finally, we examined the hierarchical structure of DSM-5 traits. In terms of internal consistency and item discrimination, the applied PID-5 scales were generally found...... reliable and functional; our data resembled the five-factor structure of previous findings, and we identified a hierarchical structure from one to five factors that was conceptually reasonable and corresponded with existing findings. These results support the new DSM-5 trait model and suggest that it can...