bluuebunny/crossref_metadata_2025 huggingface dataset:
Biofunctionalized Zinc Oxide Field Effect Transistors for Selective Sensing of Riboflavin with Current Modulation
Authors: Hagen Joshua A. , Kim Sang N. , Bayraktaroglu Burhan , Leedy Kevin , Chávez Jorge L. , Kelley-Loughnane Nancy , Naik Rajesh R. , Stone Morley O.
Published: June 2011

Zinc oxide field effect transistors (ZnO-FET), covalently functionalized with single stranded DNA aptamers, provide a highly selective platform for label-free small molecule sensing. The nanostructured surface morphology of ZnO provides high sensitivity and room temperature deposition allows for a wide array of substrate types. Herein we demonstrate the selective detection of riboflavin down to the pM level in aqueous solution using the negative electrical current response of the ZnO-FET by covalently attaching a riboflavin binding aptamer to the surface. The response of the biofunctionalized ZnO-FET was tuned by attaching a redox tag (ferrocene) to the 3’ terminus of the aptamer, resulting in positive current modulation upon exposure to riboflavin down to pM levels.
DNA Strand Patterns on Aluminium Thin Films
Authors: Khatir Nadia Mahmoudi , Banihashemian Seyedeh Maryam , Periasamy Vengadesh , Abd Majid Wan Haliza , Rahman Saadah Abdul , Shahhosseini Fatemeh
Published: June 2011

A new patterning method using Deoxyribose Nucleic Acid (DNA) strands capable of producing nanogaps of less than 100 nm is proposed and investigated in this work. DNA strands from Bosenbergia rotunda were used as the fundamental element in patterning DNA on thin films of aluminium (Al) metal without the need for any lithographic techniques. The DNA strands were applied in buffer solutions onto thin films of Al on silicon (Si) and the chemical interactions between the DNA strands and Al creates nanometer scale arbitrary patterning by direct transfer of the DNA strands onto the substrate. This simple and cost-effective method can be utilized in the fabrication of various components in electronic chips for microelectronics and Nano Electronic Mechanical System (NEMS) applications in general.
Use of Sensor Imagery Data for Surface Boundary Conditions in Regional Climate Modeling
Authors: Choi Hyun Il
Published: June 2011

Mesoscale climate and hydrology modeling studies have increased in sophistication and are being run at increasingly higher resolutions. Data resolution sufficiently finer than that of the computational model is required not only to support sophisticated linkages and process interactions at small scales but to assess their cumulative impact at larger scales. The global distributions at fine spatial and temporal scales can be described by means of various senor imagery data collected through remote sensing techniques, sensor image and photo programs, scanning and digitizing skills for existing maps, etc. The availability of global sensor imagery maps facilitates assimilation in land surface models to account for terrestrial dynamics. This study focuses on the use of global imagery data for development and construction of surface boundary conditions (SBCs) specifically designed for mesoscale regional climate model (RCM) applications. The several SBCs are currently presented in a RCM domain for the continent of Asia at 30-km spacing by using sensor imagery data. Geographic Information System (GIS) software application tools are mainly used to convert data information from various raw data onto RCM-specific grids. The raw data sources and processing procedures are elaborated in detail, by which the SBCs can be readily constructed for any specific RCM domain anywhere in the world.
Collaborative Processing of Wearable and Ambient Sensor System for Blood Pressure Monitoring
Authors: Nakamura Masayuki , Nakamura Jiro , Lopez Guillaume , Shuzo Masaki , Yamada Ichiro
Published: June 2011

This paper describes wireless wearable and ambient sensors that cooperate to monitor a person’s vital signs such as heart rate and blood pressure during daily activities. Each wearable sensor is attached on different parts of the body. The wearable sensors require a high sampling rate and time synchronization to provide a precise analysis of the received signals. The trigger signal for synchronization is provided by the ambient sensors, which detect the user’s presence. The Bluetooth and IEEE 802.15.4 wireless technologies are used for real-time sensing and time synchronization. Thus, this wearable health-monitoring sensor response is closely related to the context in which it is being used. Experimental results indicate that the system simultaneously provides information about the user’s location and vital signs, and the synchronized wearable sensors successfully measures vital signs with a 1 ms resolution.
Alphaherpesviruses and the Cytoskeleton in Neuronal Infections
Authors: Zaichick Sofia V. , Bohannon Kevin  P. , Smith Gregory   A.
Published: June 2011

Following infection of exposed peripheral tissues, neurotropic alphaherpesviruses invade nerve endings and deposit their DNA genomes into the nuclei of neurons resident in ganglia of the peripheral nervous system. The end result of these events is the establishment of a life-long latent infection. Neuroinvasion typically requires efficient viral transmission through a polarized epithelium followed by long-distance transport through the viscous axoplasm. These events are mediated by the recruitment of the cellular microtubule motor proteins to the intracellular viral particle and by alterations to the cytoskeletal architecture. The focus of this review is the interplay between neurotropic herpesviruses and the cytoskeleton.
A Water Resources Planning Tool for the Jordan River Basin
Authors: Hoff Holger , Bonzi Christopher , Joyce Brian , Tielbörger Katja
Published: June 2011

The Jordan River basin is subject to extreme and increasing water scarcity. Management of transboundary water resources in the basin is closely intertwined with political conflicts in the region. We have jointly developed with stakeholders and experts from the riparian countries, a new dynamic consensus database and—supported by hydro-climatological model simulations and participatory scenario exercises in the GLOWA (Global Change and the Hydrological Cycle) Jordan River project—a basin-wide Water Evaluation and Planning (WEAP) tool, which will allow testing of various unilateral and multilateral adaptation options under climate and socio-economic change. We present its validation and initial (climate and socio-economic) scenario analyses with this budget and allocation tool, and invite further adaptation and application of the tool for specific Integrated Water Resources Management (IWRM) problems.
Clinical Outcomes of Photoastigmatic Refractive Keratectomy for the Correction of Residual Refractive Errors Following Cataract Surgery
Authors: Kamiya Kazutaka , Umeda Kyoko , Ando Wakako , Igarashi Akihito , Shimizu Kimiya
Published: June 2011

Purpose:

To assess the clinical outcomes of photoastigmatic refractive keratectomy (PARK) for the correction of residual refractive errors after cataract surgery.

Methods:

This study evaluated 88 eyes of 66 consecutive patients with mean spherical equivalent refraction of −3.16±1.71 diopters (D) who underwent PARK to correct refractive errors after phacoemulsification with intraocular lens (IOL) implantation. Patient age at the time of surgery was 65.2±12.7 years. Safety, efficacy, predictability, stability, and adverse events of the surgery were assessed 1, 3, 6, and 12 months postoperatively.

Results:

At 1 year postoperatively, uncorrected distance visual acuity and corrected distance visual acuity were 0.08±0.16 logMAR (Snellen 20/25) and −0.08±0.11 logMAR (Snellen 20/16), respectively. Safety and efficacy indices were 1.08±0.25 and 0.76±0.28, respectively. At 1 year, 68% of eyes were within ±0.50 D and 88% were within ±1.00 D of targeted correction. Manifest refraction changes of −0.06±1.06 D occurred from 1 week to 1 year. No vision-threatening complications occurred during the observation period.

Conclusions:

Photoastigmatic refractive keratectomy is safe and moderately effective in the correction of residual refractive errors in pseudophakic eyes, suggesting its viability as a surgical option for the treatment of such eyes.
Novel Immunogenic Peptides Elicit Systemic Anaphylaxis in Mice: Implications for Peptide Vaccines
Authors: Smith Claire Mary , Bradding Peter , Neill Daniel Robert , Baxendale Helen , Felici Franco , Andrew Peter William
Published: June 2011

Peptide-based therapies are showing increasing potential for the development of vaccines and in the treatment of many important diseases. We previously reported two peptide conjugate vaccines that protected mice against pneumococcal disease. During this study, we observed an unexpected phenomenon; several vaccine candidates induced a rapid, fatal anaphylaxis after booster injection of the peptide conjugate. Further investigation indicated the reaction was mediated by the production of peptide-specific IgE and the release of histamine. Notably, among seven peptides tested, all of which bound the same mAb that selected them from a phage library, only four elicited this severe reaction. Sequence alignment analysis of all peptides revealed unique clusters of acidic amino acid residues in the allergenic peptides. Substitution of the acidic amino acid residues, ED, of peptide MP2 with their amine equivalents, QN, eliminated the anaphylactic effects but did not affect the production of peptide-specific IgG. These results have important implications for both the study of allergens and the development of future peptide-based therapies.
TLR2 Ligand Induces Protection against Cerebral Ischemia/Reperfusion Injury via Activation of Phosphoinositide 3-Kinase/Akt Signaling
Authors: Lu Chen , Liu Li , Chen Yuling , Ha Tuanzhu , Kelley Jim , Schweitzer John , Kalbfleisch John H. , Kao Race L. , Williams David L. , Li Chuanfu
Published: June 2011

This study examined the effect of TLR2 activation by its specific ligand, Pam3CSK4, on cerebral ischemia/reperfusion (I/R) injury. Mice (n = 8/group) were treated with Pam3CSK4 1 h before cerebral ischemia (60 min), followed by reperfusion (24 h). Pam3CSK4 was also given to the mice (n = 8) 30 min after ischemia. Infarct size was determined by triphenyltetrazolium chloride staining. The morphology of neurons in brain sections was examined by Nissl staining. Pam3CSK4 administration significantly reduced infarct size by 55.9% (p < 0.01) compared with untreated I/R mice. Therapeutic treatment with Pam3CSK4 also significantly reduced infarct size by 55.8%. Morphologic examination showed that there was less neuronal damage in the hippocampus of Pam3CSK4-treated mice compared with untreated cerebral I/R mice. Pam3CSK4 treatment increased the levels of Hsp27, Hsp70, and Bcl2, and decreased Bax levels and NF-κB–binding activity in the brain tissues. Administration of Pam3CSK4 significantly increased the levels of phospho-Akt/Akt and phospho-GSK-3β/GSK-3β compared with untreated I/R mice. More significantly, either TLR2 deficiency or PI3K inhibition with LY29004 abolished the protection by Pam3CSK4. These data demonstrate that activation of TLR2 by its ligand prevents focal cerebral ischemic damage through a TLR2/PI3K/Akt-dependent mechanism. Of greater significance, these data indicate that therapy with a TLR2-specific agonist during cerebral ischemia is effective in reducing injury.
Endoplasmic Reticulum Stress-Related Inflammation and Cardiovascular Diseases
Authors: Gotoh Tomomi , Endo Motoyoshi , Oike Yuichi
Published: June 2011

The endoplasmic reticulum (ER) is the site of synthesis and maturation of proteins designed for secretion or for localization on the cell membrane. Various types of stress from both inside and outside cells disturb ER function, thus causing unfolded or misfolded proteins to accumulate in the ER. To improve and maintain the ER functions against such stresses, the ER stress response pathway is activated. However, when the stress is prolonged or severe, apoptosis pathways are activated to remove damaged cells. It was recently reported that the ER stress pathway is also involved in the inflammatory response, whereby inflammation induces ER stress, and ER stress induces an inflammatory response. Therefore, the ER stress response pathway is involved in various diseases, including cardiovascular diseases such as atherosclerosis and ischemic diseases, in various ways. The ER stress pathway may represent a novel target for the treatment of these diseases.
Antimicrobial Use Guidelines for Treatment of Urinary Tract Disease in Dogs and Cats: Antimicrobial Guidelines Working Group of the International Society for Companion Animal Infectious Diseases
Authors: Weese J. Scott , Blondeau Joseph M. , Boothe Dawn , Breitschwerdt Edward B. , Guardabassi Luca , Hillier Andrew , Lloyd David H. , Papich Mark G. , Rankin Shelley C. , Turnidge John D. , Sykes Jane E.
Published: June 2011

Urinary tract disease is a common reason for use (and likely misuse, improper use, and overuse) of antimicrobials in dogs and cats. There is a lack of comprehensive treatment guidelines such as those that are available for human medicine. Accordingly, guidelines for diagnosis and management of urinary tract infections were created by a Working Group of the International Society for Companion Animal Infectious Diseases. While objective data are currently limited, these guidelines provide information to assist in the diagnosis and management of upper and lower urinary tract infections in dogs and cats.
Calcific Uremic Arteriolopathy in Peritoneal Dialysis Populations
Authors: New Nicholas , Mohandas Janaki , John George T. , Ratanjee Sharad , Healy Helen , Francis Leo , Ranganathan Dwarakanathan
Published: June 2011

Calciphylaxis or calcific uremic arteriolopathy is an infrequent complication of end stage kidney disease. It is characterized by arteriolar medial calcification, thrombotic cutaneous ischemia, tissue necrosis often leading to ulceration, secondary infection and increased mortality rates. Current, multimodality treatment involves local wound care, well-controlled calcium, phosphate and parathyroid hormone levels and combination therapy with sodium thiosulfate and hyperbaric oxygen therapy. This combination therapy may be changing the historically poor prognosis of calcific uremic arteriolopathy reported in the literature. Peritoneal dialysis is considered a risk factor based on limited publications, however this remains to be proven. Clinical presentation, diagnosis, pathogenesis and treatment of calcific uremic arteriolopathy in these patients are no different from other patients manifesting with this condition.
The Value of Future Earnings in Perfect Foresight Equilibrium
Authors: Gilbert Scott Dale
Published: June 2011

The present work considers the problem of valuing a future income stream in a perfect foresight economy. In this setting, with competitive equilibrium in labor and asset markets, market valuation of labor-generated income streams can be very simple. However, it can also be undone by moral hazard, in which case valuation may be based instead on fair compensation. I show that perfect foresight valuation emerges somewhat imperfectly in the forensic economics literature. To apply this type of valuation, the economist must form an expectation E[P] about perfect foresight price P. I consider several models of this expectation, some of which yield standard present value equations. I find that, while standard equations “fit” historical data well in some respects, they miss some dynamics that are better captured by more advanced econometric methods.
Mechanisms leading to oligomers and SOA through aqueous photooxidation: insights from OH radical oxidation of acetic acid
Authors: Tan Y. , Lim Y. B. , Altieri K. E. , Seitzinger S. P. , Turpin B. J.
Published: June 2011

Abstract. Previous experiments have demonstrated that the aqueous OH radical oxidation of methylglyoxal produces low volatility products including oxalate and oligomers. These products are found predominantly in the particle phase in the atmosphere, suggesting that methylglyoxal is a precursor of secondary organic aerosol (SOA). Acetic acid is an important intermediate in aqueous methylglyoxal oxidation and a ubiquitous product of gas phase photochemistry, making it a potential "aqueous" SOA precursor in its own right. Altieri et al. (2008) proposed that acetic acid was the precursor of oligoesters observed in methylglyoxal oxidation. However, the fate of acetic acid upon aqueous-phase oxidation is not well understood. In this research, acetic acid at concentrations relevant to atmospheric waters (20 μM–10 mM) was oxidized by OH radical. Products were analyzed by ion chromatography (IC), electrospray ionization mass spectrometry (ESI-MS), and IC-ESI-MS. The formation of glyoxylic, glycolic, and oxalic acids were observed. In contrast to methylglyoxal oxidation, succinic acid and oligomers were not detected. Using results from these and methylglyoxal + OH radical experiments, radical mechanisms responsible for oligomer formation from methylglyoxal oxidation in clouds and wet aerosols are proposed. The importance of acetic acid/acetate as an SOA precursor is also discussed. We hypothesize that this and similar chemistry is central to the daytime formation of oligomers in wet aerosols.
Daytime variations of foE connected to earthquakes
Authors: Liperovskaya E. V. , Bogdanov V. V. , Biagi P.-F. , Meister C.-V. , Liperovsky V. A.
Published: June 2011

Abstract. In the present work it is shown that, in accordance with the observations of the vertical sounding station "Tashkent", the critical foE-frequency of the daytime E-layer increases about one day before winter-earthquakes with magnitudes M > 5 and depths of the epicentre of h < 60 km, which appeared at distances of R < 2000 km from the station. The reliability of the result is larger than 99 %. The phenomenon is not observed for summer-earthquakes. It seems to be determined by the atmospheric wind system. Further, the variations of the foE-frequency are compared with possible simultaneous variations of the critical frequency foF2 of the F2-layer. First results show that only very large changes of the ionisation density in the E-layer influence the ionisation density in the F-region. Therefore, no synchronous growth of the foE- and foF2-frequencies 1–2 days before seismic shocks could be observed.
Highway Safety Effects from Rail Line Closure in Kansas
Authors: Witt Jay
Published: June 2011

This paper develops a methodology for estimating the highway safety effects resulting from rail line closure. It improves upon the previously developed methodology by recognizing both the highway safety costs and the highway safety benefits of rail line closure. The methodology is applied to a region of western Kansas with potentially endangered short line railroads. The author finds that short line abandonment in the western two-thirds of Kansas would result in net annual highway safety benefits of $1.4 million.
Redesigning the Commercial Organization of CSX: An Organizational Portfolio Analysis
Authors: Shughart Larry A. , Donaldson Lex
Published: June 2011

In 2001, CSX Corporation (CSX) reorganized the structure of its merchandise commercial group from separate groups managing each commodity-based line of business to a more functionally structured organization. The move was intended to provide greater controls and expertise required to compete successfully in a new, post-merger environment. This paper details the former and redesigned organizational structure of CSX’s railroad business. It also describes the study and analytic techniques used to support the change. Organizational Portfolio Analysis is used to examine the interconnections among the external markets and the performance fluctuations of each line of business, in order to better comprehend management's challenges, as well as to examine the internal interconnections among the lines of businesses to distinguish between areas of autonomy and synergy.
Effects of Whistle-Blowing Bans on Accidents at Gated Rail-Highway Crossings: The Northeastern Illinois Experience
Authors: Metaxatos Paul , Sriraj P. S. , Sööt Siim , DiJohn Joseph
Published: June 2011

This paper examines the effect of whistle-blowing bans on accidents at gated rail-highway public crossings in the Chicago metropolitan region. The statistical analysis show that it is rather misleading to unconditionally associate whistle bans with accident incidence and higher collision frequencies of rail-highway crossings while ignoring other factors or combinations of factors that are probably more relevant to the operational characteristics of the crossings. A deeper one delves into the interactive effects of crossing-specific characteristics on the number of accidents, the more the impact of individual factors becomes confounded so that interaction effects may even negate the effects of individual factors.
The Increasing Fatality Burden of Other Vehicle Occupants in U.S. Large Truck Accidents
Authors: Welki Andrew M. , Zlatoper Thomas J.
Published: June 2011

Since the late 1970s, occupant fatalities in U.S. large truck accidents have generally shifted from truck occupants to occupants of other vehicles (primarily autos and light trucks). This paper analyzes that shift by estimating a regression model of a death ratio (other vehicle occupant fatalities to truck occupant fatalities) using annual time-series data for the 1975-1999 period. The regression includes two ratio explanatory factors-car size to truck size, and nontruck vehicle miles to truck vehicle miles-and one non-ratio explanatory variable, the proportion of young drivers. The vehicle size ratio has a statistically significant negative relationship with the death ratio (i.e., an increase in the size ratio contributes to a shift from other vehicle occupant deaths to trucker deaths); and the vehicle miles ratio has a significant positive association with the fatality ratio (i.e., an increase in the vehicle miles ratio promotes a shift from trucker fatalities to other vehicle occupant fatalities). The proportion of young drivers has a significant negative relationship with the fatality ratio.
Safety and Security: Developing a Cooperative Process to Meet the Public Transportation Challenge
Authors: Dobie Kathryn , Hensley Rhonda
Published: June 2011

Public transit systems are faced with a dual challenge in today's security-conscious operating environment. They must continue to monitor and respond to the needs of their riders by offering easy accessibility, on-time service, and adherence to the highest of safety standards. At the same time, public transit authorities must maintain a secure environment for passengers, their workforce, equipment and facilities. This presents a formidable challenge, especially for smaller transit entities with limited resources.

A method for determining rider perceptions of the safety and security policies of their transit provider is presented. This provides a method for the transit provider to determine rider perceptions and identify opportunities for enhancing rider awareness. The suggested process also provides transit personnel with a means for identifying gaps in their existing safety and security procedures, leading to the ability to improve their safety and security posture.
Logistics Costs Based Estimation of Freight Transportation Demand
Authors: Gorman Michael F. , Conway Daniel G.
Published: June 2011

Many supply chain and fi nished goods distribution networks involve intercity freight transportation. Shipping customers secure transportation services by matching their requirements to available service in an effort to minimize their total logistics costs subject to service level constraints. Frequently, shippers' modal decisions are constrained by short-term capacity constraints restricting one of the available options, or gaps in shipper knowledge or carrier marketing programs. As a result, the observed traffic flows may not reflect the potential demand for the mode. Because the potential demand for a mode is not directly measurable, when planning road and rail capacity, governments and railroads cannot make accurate capacity planning decisions based on current traffic flows. The model developed here identifi es the potential demand for intercity full truckload and intermodal shipments over the most heavily utilized 75,000 shipment lanes in the western United States by estimating minimum total logistics costs by mode. These flows are compared with actual U.S. freight flows in order to determine the differences between observed flows and the model estimated potential demand. The results indicate potential demand for intermodal transportation is high; considerable freight volumes could be delivered with lower logistics cost by switching from truck to intermodal transportation. This evidence suggests that observed traffic flows and trends may not be a sound basis for planning freight transportation infrastructure in the United States.
Airline Passenger Profiling Systems After 9/11: Personal Privacy versus National Security
Authors: Ravich Timothy M.
Published: June 2011

This paper reviews the Transportation Security Administration's forthcoming computerized profiling system called "Secure Flight." Secure Flight is the latest generation of so-called "computer assisted passenger pre-screening systems." Such systems invite considerable privacy and civil liberty concerns, evoking references to an Orwellian society. This article confronts the central legal, political, and social tension borne of profiling systems such as Secure Flight, namely the conflict between the ideal of a "right to be let alone" (Warren and Brandeis 1890) relative to the post-Sept. 11 ultimatum of former American Airlines Chairman and CEO Robert L. Crandall (2002): "You want to travel on the airline system? You give up your privacy. You don't want to give up your privacy? Don't fly. Your privacy isn't equal to the safety of the rest of us."
On the Stock Market's Reaction to Major Railroad Accidents
Authors: Walker Thomas J. , Pukthuanthong Kuntara , Barabanov Sergey S.
Published: June 2011

This study examines the impact of train accidents on the stock price performance of the involved railroad companies. We employ a sample of 26 accidents involving trains operated by publicly traded U.S. and Canadian railroad companies between January 1993 and December 2003. Event study methodology is used to measure the abnormal performance of the involved railroad firms to these accidents. In addition, a series of univariate tests and cross-sectional regression analysis is employed to determine the factors that drive the abnormal returns for the firms in the sample. The magnitude of the initial price decline appears to be driven by various characteristics of both the firm and the accident itself. Specifically, there is strong evidence that suggests that one of the main determinants of the abnormal returns is expected legal liability claims against the railroads. Abnormal performance is negatively related to firm size and the number of injuries and fatalities resulting from the accident. In addition, accidents that result in hazardous material spills cause significantly larger stock price drops in the days following the event. Finally, investors appear to differentiate between accident causes. Accidents caused by reckless or illegal behavior on behalf of one or more of the railroad company's employees result in particularly large price declines. Accidents caused by mechanical failures or signal malfunctions, on the other hand, only cause small stock price drops.
A Game Theory Approach to Railroad-Shipper Negotiations
Authors: Huenke William
Published: June 2011

Game theory provides a framework for analyzing problems when there are a small group of participants. This is unlike the economic model of perfect competition, which requires several participants. Game theory began as a way to analyze parlor card games, but has developed into a rigorous analytical technique for evaluating strategic interactions. These interactions could be between hostile countries, competing companies, or between a shipper and railroad. In fact, game theory provides a useful structure for analyzing the interactions between a shipper and a railroad. This paper models such interactions.
Identification of Factors Leading to High Severity of Crashes in Rural Areas
Authors: Dissanayake Sunanda , Ratnayake Indike
Published: June 2011

This study made an effort to identify critical factors contributing to increased crash severities on rural highways. Crash data from the Kansas Accident Reporting System (KARS) database was analyzed and crash severity was modeled using ordered choice models. Many driver-related factors, such as alcohol involvement, lack of seat belt usage, excessive speed, and driver ejections because of the crash contribute to the increased severity of crashes in rural areas. Also, severities of single-vehicle crashes are higher than two-vehicle and animal-vehicle crashes. Factors related to roadway geometry such as sharp curves and steep grades are also found to contribute to the increased crash severity in rural areas.
Freight Transportation Demands on the Upper Mississippi and Illinois Rivers
Authors: Yu Tun-Hsiang , Zhang Jin , Fuller Stehen
Published: June 2011

This paper estimates structural demands for grain transportation on the upper Mississippi and Illinois Rivers. Grain is the predominant commodity transported on these waterways. Analysis indicates Seemingly Unrelated Regression (SUR) to be a superior method for estimating each waterway's structural demand. Results show rates, foreign and domestic demands, floods, season, and river water level influence demands. Further, the analysis suggests that a detailed analysis of river freight demand is a necessary precursor of a defendable study into the economic feasibility of improving transportation infrastructure on the upper Mississippi and Illinois Rivers.
Review and Analysis of the Effects of Major Aviation Accidents in the United States on Safety Policy, Regulation, and Technology
Authors: Lagos Alfredo , Motevalli Majid , Motevalli Vahid , Sakata Nobuyo
Published: June 2011

The authors reviewed civil air transport accidents over a 15-year period (1988-2003) and arrived at milestone accidents. The impact of these milestone accidents on aviation safety developments in policy, regulation and technology are analyzed here. The analysis shows that these accidents have led to significant changes in these three areas. However, it is concluded that the outcomes were reactive as opposed to proactive solutions. Indicators of change are U.S. Congressional and Federal Aviation Administration records and other published information. The impacts of milestone accidents are shown using a timeline format to demonstrate various sets of outcomes and their interrelation over time.
Methodologies to Predict Service Lives of Pavement Marking Materials
Authors: Zhang Yunlong , Wu Dongfeng
Published: June 2011

This study focuses on developing methodologies to predict the service life of a pavement marking material based on its retroreflectivity. Data from the 2002 National Transportation Product Evaluation Program (NTPEP) pavement marking material test deck in Mississippi are used for model development and model validation. The smoothing spline method and time series modeling are applied to estimate the service lives of different types of materials based on the assumption of a required minimum retroreflectivity value. The same models can also predict the retroreflectivity values at future times for a pavement marking product based on its retroreflectivity values in the past. The validation of the models shows satisfactory accuracy. As demonstrated in a case study, the predicted service lives of the marking materials can be used in life-cycle cost comparisons for selecting pavement marking material.
Driver Attitudes and Choices: Speed Limits, Seat Belt Use, and Drinking-and-Driving
Authors: Kweon Young-Jun , Kockelman Kara M.
Published: June 2011

A better understanding of attitudes and behavioral principles underlying driving behavior and traffic safety issues can contribute to design and policy solutions, such as speed limits and seat belt legislation. This work examines the Motor Vehicle Occupant Safety Surveys (MVOSS) dataset to illuminate drivers' seatbelt use, driving speed choices, drinking-and-driving tendencies, along with their attitudes towards speed limits and seat belt laws. Ordered probit, negative binomial, and linear regression models were used for the data analysis, and several interesting results emerged. The number and variety of results feasible with this single dataset are instructive as well as intriguing.
Developing a Strategy for Imputing Missing Traffic Volume Data
Authors: Chen Mei , Xia Jingxin , Liu Rongfang (Rachel)
Published: June 2011

Archived ITS-generated data can provide a potential resource for many long-term transportation applications. However, missing and suspicious data are inevitable due to detector and communication malfunctions. This paper presents a comparative analysis of various techniques for imputing missing traffic volume data in the archived data management system in Kentucky. The applicability of the techniques, as well as their reliability in terms of data requirement, is also discussed. An implementation strategy for the Kentucky archive data management system is then developed based on the performance and the applicability/reliability analyses.
Productivity, Pricing, and Profitability in the U.S. Rail Freight Industry, 1995-2004
Authors: Martland Carl D.
Published: June 2011

Rail industry productivity grew by 7% per year from 1984 to 1995, but most of the benefits to the industry were offset by reductions in rail rates and the increasing need for capital expenditures. Rail rates declined by more than one-third during that period, while financial measures, such as return on shareholders equity and net railway operating income, showed only a modest improvement. From 1995 to 2004, productivity improved 5% per year, prices continued to fall, and financial performance was flat or declining. There is no doubt that productivity improvements helped railroads make very significant reductions in their costs during this 20-year period. However, by 2004, the long-term trends were coming to an end. The rate of productivity improvement was declining, rates were starting to rise, and capacity and service problems were becoming more serious. With higher rates, many of the Class I railroads were coming close to earning their cost of capital. The combination of increasing profitability, declining service, and inadequate capacity is unlikely to be sustainable. The lack of capacity and deteriorating service quality are seen as serious problems not only for rail customers, but for public agencies at the local, state, and federal levels. Railroads will need financial and planning assistance from these agencies as they seek to provide sufficient capacity to handle the potential growth in traffic that is expected over the next 20 years.
The Influence of Geometry on Operational Performance of Signal-Controlled Junctions
Authors: Sermpis Dimitris
Published: June 2011

The aim of this study is to investigate the influence of geometry on the performance of signal-controlled road junctions under fixed-time and system D traffic responsive signal control by using 16 experimental scenarios with several different traffic and geometric characteristics. In the estimated log-linear models for delay per unit of time, the principal effects of lane width and turning radii were as expected. The effect on delay of the interaction between lane width and turning radii was found to be of substantial importance at light traffic flow, while the interaction between turning radii and signal control was found to play a significant role at medium traffic flow.
Freeway Speeds and Speed Variations Preceding Crashes, Within and Across Lanes
Authors: Kockelman Kara K. , Ma Jianming
Published: June 2011

Relationships between speed choice and crash occurrence have been difficult to identify. This work examines vehicle speeds (and their variations) derived from single loop detectors for several Southern California freeways, within and across freeway lanes, together with corresponding crash data. While a variety of factors clearly influence speed and speed variance, there is no evidence in these crash data sets, and observations of their corresponding series of 30-second traffic conditions, that speeds or their variation trigger crashes.
Did Passenger Fare Savings Occur After Airline Deregulation?
Authors: Richards David B.
Published: June 2011

This paper questions the generally held belief that there are significant passenger fare savings and increased passenger traffic growth due to airline deregulation. Unlike previous studies, passengers and passenger fares are broken into discrete distance intervals and compared to passenger and fare distributions prior to deregulation. Except for the period immediately before the terrorist attack in 2001 and continuing through 2005, there are limited, if any, demonstrable domestic system passenger fare savings. Also in contrast to other papers showing significant passenger fare benefits, virtually all data for this paper is accessible via the Internet.
A Review of Dynamic Traffic Assignment Computer Packages
Authors: Jeihani Mansoureh
Published: June 2011

This paper reviews the dynamic traffic assignment models in some well-known computer packages. It describes demand estimation, supply presentation, methods for computing dynamic user equilibria, and convergence among these packages with a concentration on TRANSIMS. TRANSIMS tries to take advantage of both precision and computational speed by estimating second-by-second movements of individual travelers and applying parallel processing and cellular automata methods. Although TRANSIMS addresses some of the existing problems in dynamic traffic assignment models, more studies on it and improvements in it are still needed.
The Uses of the "Temporal-Fares-Offered Curve" in Air Transportation
Authors: Button Kenneth , Vega Henry
Published: June 2011

The increasing use of Internet booking facilities provides analysts with a rich data source of the profile of airline fares offered for a particular service as the time of departure approaches – "temporal-fares-offered curves." This paper offers a critical assessment of this form of analysis. It also reviews the empirical work that has been done using this type of data and synthesizes the information and insights that it can provide on the operations of an airline market. The subjects covered range from pricing strategies of low-cost and legacy carriers under different degrees of competition, to the extent to which there is price leadership in markets, and to ways in which airlines determine fares-offered when their schedules mean that their own services effectively compete with each other.
Origin-to-Destination Performance for General Merchandise Traffic Moving to or from Short Line Railroads
Authors: Martland Carl D. , Alpert Steve
Published: June 2011

Since nearly 40% of rail freight traffic, other than coal or intermodal, originates or terminates on short lines, the service provided to short line customers is indicative of the service provided to rail customers in general. For a representative set of moves to or from short lines, the average trip time was 7.3 days with a standard deviation of about two days, which is similar to service levels documented in prior studies. A research program involving Class I railroads, short lines, customers, and public agencies would help develop effective strategies for improving service and equipment utilization for general merchandise freight.
Enabling Technologies for a Practical Wireless Communication System Operating in TV White Space
Authors: Sum Chin-Sean , Villardi Gabriel Porto , Lan Zhou , Sun Chen , Alemseged Yohannes , Tran Ha Nguyen , Wang Junyi , Harada Hiroshi
Published: June 2011

This paper proposes the design of enabling technologies for practical wireless communication systems operating in the TV white space (TVWS). The main objective of this paper is to cover a macro perspective on the system design blocks including: (a) targeted use case applications and governing regulations, (b) channelization, physical (PHY) layer and medium access control (MAC) layer designs, and (c) achievable throughput and range. It is the intention of this paper to serve as a general guideline for designing wireless communication systems operating in TVWS. The core system design addresses both PHY and MAC layer issues with realistic system considerations. In the PHY layer, a channelization design that fits into the area-specific TV channels and a transceiver that enables data exchange in the TV bands are designed. In the MAC layer, a cognitive engine that manages access to vacant TV channels and MAC functionalities that facilitate effective medium access are also proposed. As a result, the system is capable of supporting up to a typical throughput of 80 Mbps, and a maximum number of 40 users, assuming all users performing the most bandwidth-hungry application in the use case scenario. The corresponding operating range is found reach up to 400 m.
Formulation and Optimization of Sustained Release Stavudine Microspheres Using Response Surface Methodology
Authors: Dey Sanjay , Pramanik Soumen , Malgope Ananya
Published: June 2011

The aim of the current study was to formulate and optimize the formulation on the basis of in vitro performance of microsphere. A full factorial design was employed to study the effect of independent variables, polymer-to-drug ratio () and stirring speed (), on dependent variables, encapsulation efficiency, particle size, and time to 80% drug release. The best batch exhibited a high entrapment efficiency of 70% and mean particle size 290 μm. The drug release was also sustained for more than 12 hours. The study helped in finding the optimum formulation with excellent sustained drug release.
Rubber, 11. Testing
Authors: Koopmann Rüdiger , Neu Josef , Brück Dieter
Published: June 2011

The article contains sections titled:1.Purpose, Scope, and Limitations of Testing2.Physical and Mechanical Tests2.1.Test of the Viscoelasticity of Vulcanized and Unvulcanized Materials2.2.Tests on Unvulcanized Materials2.2.1.Rheometric Tests2.2.2.Curemetric Tests2.2.3.Special Tests2.3.Tests on Vulcanized Materials2.3.1.Properties of the Rubber2.3.2.Endurance and Stability2.4.Physical Material Constants3.Electrical Tests4.Rubber Analysis4.1.Compound Formulation4.2.Polymer Analysis4.3.Filler Analysis4.4.Extract Analysis4.5.Special Analyses
Prediction of Vibrational Spectra fromAbInitio Theory
Authors: Breidung Jürgen , Thiel Walter
Published: June 2011

Ab initio electronic structure theory provides potential energy and dipole moment surfaces that can be used to compute rovibrational term values and transition moments, either by normal mode analysis followed by rovibrational perturbation theory or through variational calculations. The accuracy of the theoretical spectra thus generated depends on the level of electronic structure theory and the nuclear motion treatment applied. This review surveys the currently available theoretical methods and their accuracy. Case studies are discussed to illustrate the present state of the art.
Similarity searching
Authors: Stumpfe Dagmar , Bajorath Jürgen
Published: June 2011

Similarity searching is one of the traditional and most widely applied approaches in chemical and pharmaceutical research to select compounds with desired properties from databases. The computational efficiency of many (but not all) similarity search techniques has further increased their popularity as compound databases began to rapidly grow in size. Different methods have been developed for small molecule similarity searching. However, foundations and intrinsic limitations of similarity searching are often not well understood, although a number of similarity methods are rather simplistic. Regardless of methodological details, all similarity search approaches depend on how molecular similarity is evaluated and quantified. In its essence, molecular similarity is a subjective concept and much dependent on how we represent and view molecular structures. Moreover, trying to understand the relationship between molecular similarity, however assessed, and structure‐dependent properties including, first and foremost, biological activity continues to be a challenging problem. Consequently, although similarity searching usually provides a quantitative readout and a ranking of compounds relative to chosen reference molecules, predicting structure–activity relationships on the basis of calculated similarity values often involves subjective criteria and chemical intuition. Thus, similarity searching is still far from being a routine application in database mining. In this review, we first discuss important principles underlying similarity searching, describe its tasks, and introduce major categories of search methods. Then, we focus on molecular fingerprints, the design and application of which can be regarded as a paradigm for the similarity search field. © 2011 John Wiley & Sons, Ltd. WIREs Comput Mol Sci 2011 1 260‐282 DOI: 10.1002/wcms.23

This article is categorized under:

Computer and Information Science > Databases and Expert Systems
Mixed quantum mechanics and molecular mechanics methods: Looking inside proteins
Authors: Wallrapp Frank H. , Guallar Victor
Published: June 2011

Mixed quantum mechanics and molecular mechanics (QM/MM) techniques, wherein the active site is treated with a robust ab initio quantum mechanics methodology and the remainder of the protein is modeled at the molecular mechanics level, offer a valuable tool for looking inside enzymes. We present here a short summary of recent QM/MM applications. We discuss the capabilities of this technology focusing in the main three steps when modeling enzymes: building a model, conformational sampling, and mapping the chemical process. © 2011 John Wiley & Sons, Ltd. WIREs Comput Mol Sci 2011 1 315‐322 DOI: 10.1002/wcms.27

This article is categorized under:

Structure and Mechanism > Computational Biochemistry and Biophysics
Natural bond orbital methods
Authors: Glendening Eric D. , Landis Clark R. , Weinhold Frank
Published: June 2011

Natural bond orbital (NBO) methods encompass a suite of algorithms that enable fundamental bonding concepts to be extracted from Hartree‐Fock (HF), Density Functional Theory (DFT), and post‐HF computations. NBO terminology and general mathematical formulations for atoms and polyatomic species are presented. NBO analyses of selected molecules that span the periodic table illustrate the deciphering of the molecular wavefunction in terms commonly understood by chemists: Lewis structures, charge, bond order, bond type, hybridization, resonance, donor–acceptor interactions, etc. Upcoming features in the NBO program address ongoing advances inab initiocomputing technology and burgeoning demands of its user community by introducing major new methods, keywords, and electronic structure system/NBO communication enhancements. © 2011 John Wiley & Sons, Ltd.

This article is categorized under:

Structure and Mechanism > Molecular Structures