bluuebunny/crossref_metadata_2025_split huggingface dataset:
The experience of older people living independently in Singapore
Authors: Tan K.‐K. , He H.‐G. , Chan S.W.‐C. , Vehviläinen‐Julkunen K. 
Published: June 2015

BackgroundGlobally, older people are living independently either alone or with their spouse, population continues to age. In Singapore, some may live with an unrelated older person in a public rental apartment. In Asia, these older people are associated with increased risks of poor health and social isolation, have poorer social support and a poor quality of life. Few studies have explored why these older people choose such living arrangements, the challenges they encountered and what has helped or may help them overcome these challenges.AimTo explore older people's experiences of living independently or with an unrelated older person.MethodsThis descriptive qualitative study involved face‐to‐face interviews with 25 informants, 65 years or older in Singapore. Thematic analysis was adopted.ResultsFive themes emerged: (1) making own choice – participants decided to live apart from their families, (2) contending with concerns – the availability of external resources for participants was shrinking, (3) coping with the available assistance – depending on available external resources from the community, (4) holding on to their values – participants rely on their internal resources to manage, and (5) preparing for the inevitable – participants were planning for their final years of life and for their death.ConclusionOlder people have such living arrangements for many reasons. They attain well‐being and quality of life by devising strategies, tapping on their limited external resources and relying on their values to manage their diminishing resources and the foreseeable death.Implications for nursing and/or health policyUnderstanding older people's experiences may help nurses and health professionals to develop health promotion programmes that support older people's everyday needs and help them to stay healthy. Public health policy must support older people to live in a safe environment near their extended family to reduce their need to relocate.
Democratic Legitimacy and the Paradox of Persisting Opposition
Authors: González‐Ricoy Iñigo 
Published: June 2015

AbstractThe paradox of persisting opposition raises a puzzle for normative accounts of democratic legitimacy. It involves an outvoted democrat who opposes a given policy (because she takes it to be unjust) while supporting it (because it is the upshot of majority rule). The article makes a threefold contribution to the existing literature. First, it considers pure proceduralist and pure instrumentalist alternatives to solve the paradox and finds them wanting — on normative, conceptual, and empirical grounds. Second, it presents a solution based on a two‐level distinction between substantive and procedural legitimacy that shows that citizens are consistent in endorsing the upshot of democratic procedures while opposing it. Third, it unpacks three reasons to non‐instrumentally endorse such procedures — namely, the presence of reasonable disagreement, non‐paternalism, and the right to democratically do wrong. In so doing, the article shows that those accounts of democratic legitimacy that rely on reasonable disagreement as a necessary condition for democratic procedures being called for are flawed, or at least incomplete, and offers a more complete alternative.
High Speed Curving Performance of Rail Vehicles
Authors: Marquis Brian , Greif Robert 
Published: June 2015

On March 13, 2013, the Federal Railroad Administration (FRA) published a final rule titled “Vehicle/Track Interaction Safety Standards; High-Speed and High Cant Deficiency Operations” which amended the Track Safety Standards (49 CFR Part213) and the Passenger Equipment Safety Standards (49 CFR Part 238) in order to promote VTI safety under a variety of conditions at speeds up to 220 mph [1]. Among its main accomplishments, the final rule facilitates the expansion of higher speed passenger rail by revising the standards governing permissible operating speed in curves, allowing for higher cant deficiencies in all FRA Track Classes. To ensure safety is not diminished, the FRA Track Safety Standards require railroads to maintain their tracks to stricter track geometry standards whenever they operate at these higher curving speeds and cant deficiencies. These revisions were based on studies that examined the dynamic curving performance of various representative rail vehicles.
This research investigates the steady-state curving performance of truck designs while traversing curves at various curving speeds and cant deficiencies. During steady-state curve negotiation, the axles of trucks generally offset laterally from the track centerline and develop angles of attack increasing the wheel-rail contact forces. Large lateral forces can develop, particularly in flange contact, resulting in increased wheel and rail wear, track panel shift, and the risk of derailment. Depending on the truck design, such forces become larger at higher cant deficiency. An understanding of the steady-state response of a rail vehicle in a curve is essential as it represents a significant part of the total dynamic response.
The curving performance of an idealized rigid truck is analyzed using nonlinear analytical methods for a wide range of operating speeds and unbalance conditions. Emphasis is placed on higher speed curving and the results are used to interpret trends observed during recent field testing with Amtrak’s Acela High-Speed Trainset on the Northeast Corridor.
Combining Track Quality and Performance Measures to Assess Track Maintenance Requirements
Authors: Roghani Alireza , Macciotta Renato , Hendry Michael 
Published: June 2015

The serviceability of a section of railway highly depends on track stiffness and roughness. Railway operators regularly measure parameters associated with track stiffness and roughness to evaluate the track conditions. These measures are used in combination with performance observations to assess maintenance requirements. Although these assessments are mostly qualitative, railway operations have benefited from them. Railway operators keep comprehensive records of different types of track defects along their lines. These records are a measure of track performance and present an opportunity to quantify the relationship between track quality and performance. This brings the possibility of developing a performance-based approach for assessing the maintenance requirement along a railway track.
In this paper, a database of track geometry defects along Canadian National Railway’s Lac la Biche subdivision (Alberta) has been compared against measured parameters associated with track roughness and stiffness. The analyses confirm the relationship between track stiffness and roughness, and the occurrence of track defects. This relationship is further used to define threshold values of track roughness and stiffness, and a hazard chart for maintenance requirements along the Lac la Biche subdivision is proposed.
Modeling the Behavior of Pre-Stressed Concrete Railroad Ties
Authors: Haynes Mark D. , Wu Chih-Hang John , Bodapati Naga Narendra B. , Beck B. Terry , Peterman Robert J. 
Published: June 2015

Early failure of pre-stressed concrete railroad ties in the field is a costly occurrence with modern ties. A key predictor of the performance of a pre-stressed concrete cross tie is the transfer length. Assuring that the transfer length is less than the position of the rail seat is necessary to establish the full pre-stressing force at the load point of the concrete tie.
Models have been developed based upon empirical data to predict the transfer length of concrete members given key design parameters. Given the release strength and design geometry of the reinforcement steel, accurate predictions can be made as to what the anticipated transfer length will be. The geometry of the indented profile in pre-stressing steel has been found to be critical for minimizing the fracture propensity of the concrete member and reducing the overall transfer length. Edge wall angles of the reinforcement wire indents have been shown within this study to have a critical influence on the fracture propensity of the concrete medium. Steel produced with too shallow or too steep indent edge wall angles generate excessive internal forces rupturing the concrete.
By modeling the behavior of the transfer length in concrete members, the design and production tolerances can be better controlled increasing the life expectancy of concrete ties. This results in decreased costs for the rail infrastructure and greater uptime of tracks utilizing pre-stressed concrete railroad ties. By improving the overall design of concrete members and by improving the quality control tests used during production a longer lasting and lower cost product may be achieved.
Effect of Prestressing Wire Indentation Type on the Development Length and Flexural Capacity of Pretensioned Concrete Crossties
Authors: Momeni Amir Farid , Peterman Robert J. , Beck B. Terry , Wu Chih-Hang John , Bodapati Naga Narendra B. 
Published: June 2015

Load tests were conducted on pretensioned concrete prisms cast with 13 different 5.32-mm-diameter prestressing wire types that are used in the manufacture of pretensioned concrete railroad ties worldwide. The tests were specifically designed to evaluate the development length and bonding performance of these different reinforcements. The prestressing wires were denoted “WA” through “WM” and indentation types included smooth, spiral, chevron, diamond, and 2-dot and 4-dot. Four wires were embedded into each concrete prism, which had a 3.5″ (88.9 mm) × 3.5″ (88.9 mm) square cross section. The wires were initially tensioned to 7000 pounds (31.14 KN) and gradually de-tensioned when the concrete compressive strength reached 4500 psi (31.03 Mpa). A consistent concrete mixture with type III cement, water-cement ratio of 0.32 and a 6-in. slump was used for all prisms.
Prisms were tested in 3-point-bending at different spans to obtain estimations of the development length of each type of reinforcement. Two identical 69-in.-long (175.26 cm) prisms were load tested, at both ends, for each reinforcement type evaluated. First prisms were tested at 20-in. (50.8 cm) from one end and 13-in. (33.02 cm) from the other end, whereas the second prisms were loaded at 16.5-in. (41.9 cm) from one end and 9.5-in. (24.13 cm) from the other end. Thus, a total of 52 load tests (13 wire types × 4 tests each) were conducted in this study.
During each test, a concentrate load with the rate of 300 lb/min (1334 N/min) was applied at mid-span until failure occurred, and values of load, mid-span deflection, and wire end-slip were continuously monitored and recorded. Plots of load-vs-deflection were then compared for prisms with each wire type and span, and the maximum sustained moment was also calculated for each test. The load tests revealed that there is a very large difference in the development length of the different wire types currently used in the manufacture of pretensioned concrete railroad ties. The results imply that there would also likely be large differences in the reserve capacity (beyond first cracking) for pretensioned concrete crossties fabricated with these different reinforcements.
Investigation of Parameters Influencing Hunting Performance of a Railway Vehicle With Three-Piece Trucks
Authors: Taheri Mehdi , Ahmadian Mehdi 
Published: June 2015

This study uses a nonlinear multibody dynamics model of a railway vehicle with three-piece trucks to perform a parametric study on a wide range of parameters influencing the performance of the truck on tangent track. One of the major disadvantages of the three-piece truck is that its performance can be greatly influenced due to worn parts or contaminants on friction surfaces, such as the friction wedge. The influence of worn parts is modeled as increased gap between bodies, using dead-band springs. The influence of environmental contamination is modeled as change in coefficients of friction. Lateral accelerations, measured at the center of gravity of the leading axle of the leading truck (Axle 1) are used for the hunting performance of the vehicle. For the baseline case, an eigenvalue analysis of a linearized model is used to evaluate the effect of speed on damping ratio and lateral motion frequency. A comparison of the linear model and non-linear time series analysis show that the linear model is less conservative, in that it predicts that the onset of hunting occurs at higher speeds.
The results indicate a direct relationship between various coefficients of friction and hunting velocity of the rail vehicle. Increasing the gap between the pedestal legs and bearing housing does not influence hunting velocity, but reduces lateral acceleration magnitudes during hunting. The weights of the carbody and cargo also has a direct relationships with hunting velocity, meaning that hunting occurs at lower speeds for unloaded car and at higher speeds for a loaded car.
Passenger Rail in Indiana: From Our Past to Our Future
Authors: Pyrialakou V. Dimitra , Gkritza Konstantina 
Published: June 2015

The Midwest railroad network connected almost every major city by 1860, accounting for 36% of the United States (U.S.) railroad network mileage. Indiana became famous for the first Union Station in the world, as well as for one of the most developed and luxurious interurban rail system in the U.S. The twentieth century drastically transformed the picture, endowing the country with well-developed and world class highway and aviation networks, but leaving Indiana with a limited passenger rail network.
Today, the Hoosier State line, which operates between Indianapolis, Indiana and Chicago, Illinois, is in danger of elimination. As of October 2013, the State of Indiana, local communities, and Amtrak reached an agreement to support the Hoosier State line, an agreement recently extended through January 2015. Amtrak is hesitant to support the corridor, doubting its economic viability. In response, the Indiana Department of Transportation (DOT) was the first nationally to announce a Request for Proposals (1404s1) under the Passenger Rail Investment and Improvement Act in order to obtain competitive bids for the operation of the Hoosier State line.
Recent studies suggest that the improvement and enhancement of the Midwest regional rail system to allow higher speeds has the potential to significantly benefit the area. The route from Chicago to Cincinnati via Indianapolis is a strong candidate among the possible routes in the Midwest, and within the second tier nationwide. Studies also suggest that such an upgrade can return great user benefits, reduce travel times, and bring significant regional economic benefits supporting the creation of new permanent jobs in Indiana.
This paper presents the chronicle of passenger rail transportation in the U.S., Midwest, and Indiana in particular, from the early 1830s to the recent attempts of the State of Indiana to sustain the Hoosier line. This paper also investigates the effect of the community’s support on Indiana’s passenger rail evolution, as well as the potential of “higher” speed rail in the state.
Conformational Change Observed in the Active Site of Class C β-Lactamase MOX-1 upon Binding to Aztreonam
Authors: Oguri Takuma , Ishii Yoshikazu , Shimizu-Ibuka Akiko 
Published: June 2015

ABSTRACT
We solved the crystal structure of the class C β-lactamase MOX-1 complexed with the inhibitor aztreonam at 1.9Å resolution. The main-chain oxygen of Ser315 interacts with the amide nitrogen of aztreonam. Surprisingly, compared to that in the structure of free MOX-1, this main-chain carboxyl changes its position significantly upon binding to aztreonam. This result indicates that the interaction between MOX-1 and β-lactams can be accompanied by conformational changes in the B3 β-strand main chain.
The RNA Helicase DeaD Stimulates ExsA Translation To Promote Expression of the Pseudomonas aeruginosa Type III Secretion System
Authors: Intile Peter J. , Balzer Grant J. , Wolfgang Matthew C. , Yahr Timothy L. 
Published: June 2015

ABSTRACT

The
Pseudomonas aeruginosa
type III secretion system (T3SS) is a primary virulence factor important for phagocytic avoidance, disruption of host cell signaling, and host cell cytotoxicity. ExsA is the master regulator of T3SS transcription. The expression, synthesis, and activity of ExsA is tightly regulated by both intrinsic and extrinsic factors. Intrinsic regulation consists of the well-characterized ExsECDA partner-switching cascade, while extrinsic factors include global regulators that alter
exsA
transcription and/or translation. To identify novel extrinsic regulators of ExsA, we conducted a transposon mutagenesis screen in the absence of intrinsic control. Transposon disruptions within gene PA2840, which encodes a homolog of the
Escherichia coli
RNA-helicase DeaD, significantly reduced T3SS gene expression. Recent studies indicate that
E. coli
DeaD can promote translation by relieving inhibitory secondary structures within target mRNAs. We report here that PA2840, renamed DeaD, stimulates ExsA synthesis at the posttranscriptional level. Genetic experiments demonstrate that the activity of an
exsA
translational fusion is reduced in a
deaD
mutant. In addition,
exsA
expression in
trans
fails to restore T3SS gene expression in a
deaD
mutant. We hypothesized that DeaD relaxes mRNA secondary structure to promote
exsA
translation and found that altering the mRNA sequence of
exsA
or the native
exsA
Shine-Dalgarno sequence relieved the requirement for DeaD
in vivo
. Finally, we show that purified DeaD promotes ExsA synthesis using
in vitro
translation assays. Together, these data reveal a novel regulatory mechanism for
P. aeruginosa
DeaD and add to the complexity of global regulation of T3SS.

IMPORTANCE
Although members of the DEAD box family of RNA helicases are appreciated for their roles in mRNA degradation and ribosome biogenesis, an additional role in gene regulation is now emerging in bacteria. By relaxing secondary structures in mRNAs, DEAD box helicases are now thought to promote translation by enhancing ribosomal recruitment. We identify here an RNA helicase that plays a critical role in promoting ExsA synthesis, the central regulator of the
Pseudomonas aeruginosa
type III secretion system, and provide additional evidence that DEAD box helicases directly stimulate translation of target genes. The finding that DeaD stimulates
exsA
translation adds to a growing list of transcriptional and posttranscriptional regulatory mechanisms that control type III gene expression.
ABC Transporter Required for Intercellular Transfer of Developmental Signals in a Heterocystous Cyanobacterium
Authors: Videau Patrick , Rivers Orion S. , Higa Kelly C. , Callahan Sean M. 
Published: June 2015

ABSTRACT

In the filamentous cyanobacterium
Anabaena
,
patS
and
hetN
encode peptide-derived signals with many of the properties of morphogens. These signals regulate the formation of a periodic pattern of heterocysts by lateral inhibition of differentiation. Here we show that intercellular transfer of the
patS
- and
hetN
-dependent developmental signals from heterocysts to vegetative cells requires HetC, a predicted ATP-binding cassette transporter (ABC transporter). Relative to the wild type, in a
hetC
mutant differentiation resulted in a reduced number of heterocysts that were incapable of nitrogen fixation, but deletion of
patS
or
hetN
restored heterocyst number and function in a
hetC
background. These epistasis results suggest that HetC is necessary for conferring self-immunity to the inhibitors on differentiating cells. Nine hours after induction of differentiation, HetC was required for neither induction of transcription of
patS
nor intercellular transfer of the
patS
-encoded signal to neighboring cells. Conversely, in strains lacking HetC, the
patS
- and
hetN
-encoded signals were not transferred from heterocyst cells to adjacent vegetative cells. The results support a model in which the
patS
-dependent signal is initially transferred between vegetative cells in a HetC-independent fashion, but some time before morphological differentiation of heterocysts is complete, transfer of both signals transitions to a HetC-dependent process.

IMPORTANCE
How chemical cues that regulate pattern formation in multicellular organisms move from one cell to another is a central question in developmental biology. In this study, we show that an ABC transporter, HetC, is necessary for transport of two developmental signals between different types of cells in a filamentous cyanobacterium. ABC transporters are found in organisms as diverse as bacteria and humans and, as the name implies, are often involved in the transport of molecules across a cellular membrane. The activity of HetC was shown to be required for signaling between heterocysts, which supply fixed nitrogen to the organism, and other cells, as well as for conferring immunity to self-signaling on developing heterocysts.
Two Proteins Form a Heteromeric Bacterial Self-Recognition Complex in Which Variable Subdomains Determine Allele-Restricted Binding
Authors: Cardarelli Lia , Saak Christina , Gibbs Karine A. 
Published: June 2015

ABSTRACT

Self- versus nonself-recognition in bacteria has been described recently through genetic analyses in multiple systems; however, understanding of the biochemical properties and mechanisms of recognition-determinant proteins remains limited. Here we extend the molecular and biochemical understanding of two recognition-determinant proteins in bacteria. We have found that a heterotypic complex is formed between two bacterial self-recognition proteins, IdsD and IdsE, the genes of which have been shown to genetically encode the determinants for strain-specific identity in the opportunistic bacterial pathogen
Proteus mirabilis
. This IdsD-IdsE complex forms independently of other
P. mirabilis
-encoded self-recognition proteins. We have also shown that the binding between IdsD and IdsE is strain- and allele-specific. The specificity for interactions is encoded within a predicted membrane-spanning subdomain within each protein that contains stretches of unique amino acids in each
P. mirabilis
variant. Finally, we have demonstrated that this
in vitro
IdsD-IdsE binding interaction correlates to
in vivo
population identity, suggesting that the binding interactions between IdsD and IdsE are part of a cellular pathway that underpins self-recognition behavior in
P. mirabilis
and drives bacterial population sociality.

IMPORTANCE
Here we demonstrate that two proteins, the genes of which were genetically shown to encode determinants of self-identity in bacteria, bind
in vitro
in an allele-restricted interaction, suggesting that molecular recognition between these two proteins is a mechanism underpinning self-recognition behaviors in
P. mirabilis
. Binding specificity in each protein is encapsulated in a variable region subdomain that is predicted to span the membrane, suggesting that the interaction occurs in the cell envelope. Furthermore, conversion of binding affinities
in vitro
correlates with conversion of self-identity
in vivo
, suggesting that this molecular recognition might help to drive population behaviors.