bluuebunny/crossref_metadata_2025 huggingface dataset:
Rochas silicáticas portadoras de potássio como fontes do nutriente para as plantas solo
Authors: Ribeiro Luciano da Silva , Santos Anacleto Ranulfo dos , Souza Luiz Francisco da Silva , Souza Jamile Santana
Published: August 2010

O objetivo deste trabalho foi avaliar, em casa de vegetação, o efeito da aplicação de pó de rochas silicáticas portadoras de K (ultramáfica alcalina, brecha piroclástica e flogopitito) na liberação de K e sobre outros atributos químicos do solo. Foi utilizado um Latossolo Amarelo distrófico coeso com teor de K de 0,03 cmol c dm-3 de solo. As rochas foram testadas sem e com correção da acidez do solo - neste caso, elevando o valor da saturação por bases para 70 %. Inicialmente, as rochas e o corretivo de acidez foram aplicados e incorporados aos solos de cada vaso com 3 kg de solo, deixando-os em incubação por um período de 45 dias, com a umidade em torno de 80 % da capacidade de campo. Foram testadas as doses equivalentes a 75, 150, 225 e 300 kg ha-1 K2O de todas as rochas e do KCl, usado como fonte de referência. Findo o período de incubação, foi realizado um plantio de soja com a finalidade de observar a dissolução das rochas em um ambiente com plantas. As plantas foram colhidas 50 dias depois do plantio. Foram feitas análises do solo após o período de incubação e depois do plantio da soja. As rochas ultramáfica alcalina e brecha piroclástica foram as que mais liberaram K para o solo; a correção da acidez não influenciou o processo de dissolução das rochas.
Physical properties of dystrophic Red Latosol (Oxisol) under different agricultural uses
Authors: Tavares Filho João , Barbosa Graziela Moraes de Cesare , Ribon Adriana Aparecida
Published: August 2010

Obtaining information about soil properties under different agricultural uses to plan soil management is very important with a view to sustainability in the different agricultural systems. The aim of this study was to evaluate changes in certain indicators of the physical quality of a dystrophic Red Latosol (Oxisol) under different agricultural uses. The study was conducted in an agricultural area located in northern Paraná State. Dystrophic Red Latosol samples were taken from four sites featuring different types of land use typical of the region: pasture of Brachiaria decumbens (P); sugarcane (CN); annual crops under no-tillage (CAPD); and native forest (permanent conservation area) (control (C)). For each land use, 20 completely randomized, disturbed and undisturbed soil samples were collected from the 0-20 cm soil layer, to determine soil texture, volume of water-dispersible clay, soil flocculation (FD), particle density, quantity of organic matter (OM), soil bulk density (Ds), soil macroporosity (Ma) and microporosity (Mi), total soil porosity (TSP), mean geometric diameter of soil aggregates (MGD), and penetration resistance (PR). The results showed differences in OM, FD, MGD, Ds, PR, and Ma between the control (soil under forest) and the areas used for agriculture (P, CN and CAPD). The soils of the lowest physical quality were those used for CN and CAPD, although only the former presented a Ma level very close to that representing unfavorable conditions for plant growth. For the purposes of this study, the physical properties studied were found to perform well as indicators of soil quality.
Identificação de genótipos do gênero Solanum (secção Lycopersicon) com resistência a Stemphylium solani e S. lycopersici
Authors: Miranda Bruno Eduardo C de , Boiteux Leonardo S , Reis Ailton
Published: August 2010

A mancha-de-estenfílio do tomateiro, causada pelos fungos Stemphylium solani e S. lycopersici, foi considerada, por muito tempo, como uma doença secundária devido à utilização combinada de fungicidas e variedades resistentes. Recentemente, severas epidemias da mancha-de-estenfilio têm sido relatadas nas várias regiões produtoras sugerindo a necessidade de retomar o emprego de cultivares com resistência a esta enfermidade. O objetivo do presente trabalho foi avaliar a reação de genótipos cultivados e silvestres de tomateiro [Solanum (secção Lycopersicon)] frente a isolados destas duas espécies de Stemphylium. Na primeira etapa do trabalho, 109 genótipos de Solanum (secção Lycopersicon) foram avaliados via inoculação com uma suspensão de 10(4) conídios/mL dos isolados 'EH-1740' (S. solani) e 'EH-1749' (S. lycopersici). As plantas foram transplantadas aos 18 dias da semeadura e inoculadas sete dias depois. A avaliação da resposta dos genótipos foi feita 15 dias após a inoculação. Cinqüenta e oito genótipos considerados promissores foram novamente avaliados (com os mesmos isolados) em um segundo experimento. Neste experimento a reação dos genótipos foi avaliada cada dois dias utilizando como critérios o período de incubação e a severidade da doença através de uma escala de notas de 0 a 5. Com os valores de severidade, nas diferentes leituras, foi calculada a área abaixo da curva de progresso da doença e o índice de doença. Foram identificadas 35 fontes de resistência às duas espécies de Stemphylium em genótipos das espécies S. lycopersicum, S. habrochaites, S. peruvianum e S. pimpinellifolium. Os genótipos de S. lycopersicum e S. pimpinellifolium resistentes possuem, provavelmente, o gene de resistência Sm. No entanto, os genótipos de S. peruvianum e S. habrochaites podem representar fontes de novos genes/alelos que conferem resistência às duas espécies fúngicas. Esta potencial diversidade de fatores de resistência para Stemphylium pode ser útil em futuras ações de pesquisa dentro de programas de melhoramento genético do tomateiro bem como para o manejo integrado da doença.
Comportamento masculino diante da mulher com Síndrome Pré-Menstrual: narrativas de mulheres
Authors: Hoga Luiza Akiko Komura , Vulcano Marcela Alexandre , Miranda Carolina Morais , Manganiello Adriana
Published: August 2010

OBJETIVO: Descrever as percepções de mulheres com Síndrome Pré-Menstrual a respeito do comportamento de seus parceiros diante delas. MÉTODOS: Pesquisa de abordagem qualitativa com desenvolvimento das cinco etapas do método de análise da narrativa para conhecer as representações a respeito dessa experiência. RESULTADOS: As experiências das 20 mulheres entrevistadas estão representadas nas categorias: Dificuldades para identificar a síndrome e adotar práticas de cuidado; Falta de conhecimento e sensibilidade dos homens e suas consequências sobre a relação entre o casal. CONCLUSÃO: Orientações sistematizadas sobre a Síndrome Pré-Menstrual devem ser fornecidas a todas as pessoas, em momento anterior à menarca, para evitar o surgimento de problemas decorrentes do desconhecimento da síndrome e suas consequências nas esferas pessoal, familiar e social das mulheres.
Self-managing osteoporosis treatment for well-being recovery mediated by the (in)visibility of the disease signs
Authors: Souza Luciana Bronzi de , Mazeto Gláucia Maria Ferreira da Silva , Bocchi Silvia Cristina Mangini
Published: August 2010

The present study aimed to understand patients’ experience with osteoporosis treatment. The methodological and theoretical frameworks were, respectively, the Grounded Theory and Symbolic Interactionism. The research subjects were 12 patients monitored in a specialized outpatient unit. The obtained statements were transcribed and analyzed, leading to a synthesis of the described themes. From the analysis process, two phenomena emerged: “self-evaluating health conditions according to the disease signs” and “making a decision about the treatment targeting at well-being”. The realignment and the inter-relationship of the components belonging to these phenomena (themes, categories, and subcategories) allowed to identify the core category: “self-managing osteoporosis treatment for well-being recovery mediated by the (in)visibility of the disease signs”. Furthermore, it allowed for the design of a theoretical model concerning the process used by the player in his cyclic movement of the experience, between adherence to and relaxation from the osteoporosis treatment.
Expanding roles of NUCB2/nesfatin-1 in neuroendocrine regulation
Authors: García-Galiano David , Navarro Victor M , Gaytan Francisco , Tena-Sempere Manuel
Published: August 2010

Nesfatin-1 was originally identified as a hypothalamic neuropeptide, derived from the precursor NEFA (for DNA binding/EF-hand/acidic protein)/nucleobindin 2 (NUCB2), with the ability to suppress food intake, acting in a leptin-independent manner. Departing from this seminal finding, the patterns of expression of NUCB2/nesfatin-1 have been thoroughly characterized in different hypothalamic nuclei and brain areas with proven roles in energy homeostasis, and its potential interactions with other key neuropeptide regulators of appetite have been documented. Intriguingly, recent experimental evidence suggests that NUCB2/nesfatin-1 is also expressed in peripheral tissues with relevant metabolic functions, such as the pancreas, the adipose, and the gut. In addition, evidence is mounting that nesfatin signaling may participate in adaptative responses and in the control of body functions gated by the state of energy reserves, such as puberty onset. Altogether, these observations have broadened our perception of the biological profile of nesfatin-1 that, rather than a simple anorectic signal in the hypothalamus, might operate at different tissues as an integral regulator of energy homeostasis and closely related neuroendocrine functions.
The role of higher thoracic irradiation doses in patients with limited stage of small-cell lung cancer: Retrospective study
Authors: Scepanovic Danijela , Bajic Nada , Zivkovic Danko , Mijovic Milan
Published: August 2010

Background: Small-cell lung cancer is highly chemo- and radiosensitive tumor. We evaluated two different radiotherapy doses applied sequentially with chemotherapy in relation to time to progression, progression free survival, and overall survival in patients with limited disease of small cell lung cancer. Methods: From 1998 to 2003, 81 patients were treated for small-cell lung carcinoma. Median age was 57 years (range, 36-77 years) and female: male ratio was 1:4. Patients were initially treated with four cycles of chemotherapy during three weeks (cisplatin 80mg/m2 IV, day 1 and etoposide 100 mg/m2 IV, days 1 - 3). One month later, patients received up to 44 Gy, 2 Gy per day, 5 days per week (group I, 41 patients) or above 44 Gy, standard fractionation (group II, 40 patients), to mediastinum and tumor. Range of higher radiotherapy doses was 54 Gy to 64 Gy, standard fractionation. We evaluated if different radiotherapy doses had any influence on time to progression, progression free survival, and overall survival. Results: The median follow up time was 23 months (range, 12-72 months) for both groups of patients (81). The median time to progression in group I of patients (41) was 13 months (range, 11-29 months) while median time to progression in group II of patients (40) was 20 months (min=9, max=60). There was no statistically significant difference in relapse rate between two groups of patients (p>0.05, Fisher test). However, there was difference but not statistically significant in one-year progression free survival (p=0.05, chi square test) between groups, while there was statistically significant difference in two-year progression free survival favoring higher doses of radiotherapy (p<0.05, chi-square test). The median overall survival was 18 months (range, 12-35 months) for group I of patients and 28 months (range, 15-72 months) for group II of patients. There was no statistically significant advantage between two groups of patients for one-year overall survival (p>0.05, chi-square test). However, there was statistically significant difference in overall survival favoring higher radiotherapy doses for two-year overall survival (p<0.05, chi-square test). Conclusion: We found that higher radiotherapy doses had an impact on long-term time to progression, progression free survival, and overall survival (2 years) of patients.
The results of surgical treatment of metastatic liver tumor
Authors: Petrovic Tomislav , Majdevac Ivan , Budisin Nikola , Radovanovic Zoran , Nikolic Ivan , Nikin Zoran , Gavrancic Brane , Mihailovic Jasna
Published: August 2010

Background: The aim of our study was to analyze the survival of patients who were operated from liver metastases. This paper is a retrospective study of the case reports from the Clinic for Operative Oncology - Oncology Institute of Vojvodina. The study included all the patients treated operatively for secondary malignant liver tumors in the period from May 2003 to May 2007. Methods: The study included 33 patients (17 men and 16 women). The mean age of patients was 57.8 years (range, 27-75 years). In 23 patients, (69.7%) metastases were of colorectal origin, while in 10 patients (30.3%) metastases originated from some other organs. Results: Hepatectomies were performed in 54.54% and metastasectomies in 45.45% of patients. More severe postoperative complications (which required repeated surgery) were registered in 3.03% of patients. Intraoperative mortality was 3.03% and postoperative mortality was 12.12%. Liver re-resection was performed in 21.21% of patients. An overall one-year survival was 75.76%, and a tree-year survival was 43.75%. One-year survival in patients with colorectal metastases was 86.96% and three-year survival was 50%, while in patients with metastases originating from some other organs, one-year survival was 70% and three-year survival was only 25%. Intrahospital mortality in patients with colorectal metastases was 8.7% while in patients with non-colorectal metastases it was 30%. Conclusion: The aim of this paper was to show that only surgical removal of metastases can lead to life quality improvement and to prolongation of the overall survival and that modern neoadjuvant and biological therapies may increase resectability of the inoperable changes.
Antiestrogen therapy in recurrent ovarian cancer resulting in 28 months of stable disease: A case report and review of the literature
Authors: Kothari Rajul , Argenta Peter , Fowler Jeffrey , Carter Jori , Shimp William
Published: August 2010

Hormonal therapy for adjuvant treatment of ovarian cancer may provide a low toxicity option in some patients with refractory disease. A 53 year-old patient with stage IIIC papillary serous ovarian cancer previously treated with multiple chemotherapy regimens with platinum-resistant disease was treated with antiestrogen therapy for 28 months before requiring reinstitution of cytotoxic chemotherapy. Hormonal therapy may be effective in a subset of epithelial ovarian cancer patients with endocrine sensitivity and should be considered in the treatment of platinum-resistant patients.
Interaction between tryptophan-vanillin Schiff base and herring sperm DNA
Authors: Zhang Yan , Wang Xingming , Ding Lisheng
Published: August 2010

The interaction of the Schiff base (K[HL]) with herring sperm DNA was studied by UV-vis absorption, fluorescence and viscosity methods in a physiological pH environment (pH 7.40), where the Schiff base was derived from vanillin and L-tryptophan. A binding ratio of nK[HL]:nDNA = 5:1 and an apparent molar absorption coefficient of ?K[HL]-DNA = 4.98 ? 105 L?mol-1?cm-1 were confirmed by the mole ratio method. The binding constants of KB ? 28?C = 1.94 ? 105 L?mol-1 and KB ? 37?C = 1.09 ? 105 L?mol-1 were obtained by the double reciprocal method. Thermodynamic parameters suggest that the interaction between K[HL] and DNA is driven mainly by enthalpy. Combined with Scatchard methods and viscosity methods, the results indicate the presence of intercalation and groove binding between K[HL] and DNA.
Obesity Is a Fibroblast Growth Factor 21 (FGF21)-Resistant State
Authors: Fisher ffolliott M. , Chui Patricia C. , Antonellis Patrick J. , Bina Holly A. , Kharitonenkov Alexei , Flier Jeffrey S. , Maratos-Flier Eleftheria
Published: August 2010

OBJECTIVE

Fibroblast growth factor 21 (FGF21) is a key mediator of fatty acid oxidation and lipid metabolism. Pharmacological doses of FGF21 improve glucose tolerance, lower serum free fatty acids, and lead to weight loss in obese mice. Surprisingly, however, FGF21 levels are elevated in obese ob/ob and db/db mice and correlate positively with BMI in humans. However, the expected beneficial effects of endogenous FGF21 to increase glucose tolerance and reduce circulating triglycerides are absent in obesity.

RESEARCH DESIGN AND METHODS

To test the hypothesis that obesity is a state of FGF21 resistance, we evaluated the response of obese mice to exogenous FGF21 administration. In doing this, we assessed the impact of diet-induced obesity on FGF21 signaling and resultant transcriptional events in the liver and white adipose tissue. We also analyzed the physiologic impact of FGF21 resistance by assessing serum parameters that are acutely regulated by FGF21.

RESULTS

When obese mice are treated with FGF21, they display both a significantly attenuated signaling response as assessed by extracellular mitogen-activated protein kinase 1 and 2 (ERK1/2) phosphorylation as well as an impaired induction of FGF21 target genes, including cFos and EGR1. These effects were seen in both liver and fat. Similarly, changes in serum parameters such as the decline in glucose and free fatty acids are attenuated in FGF21-treated DIO mice.

CONCLUSIONS

These data demonstrate that DIO mice have increased endogenous levels of FGF21 and respond poorly to exogenous FGF21. We therefore propose that obesity is an FGF21-resistant state.
Insulin Transactivator MafA Regulates Intrathymic Expression of Insulin and Affects Susceptibility to Type 1 Diabetes
Authors: Noso Shinsuke , Kataoka Kohsuke , Kawabata Yumiko , Babaya Naru , Hiromine Yoshihisa , Yamaji Kaori , Fujisawa Tomomi , Aramata Shinsaku , Kudo Takashi , Takahashi Satoru , Ikegami Hiroshi
Published: August 2010

OBJECTIVE

Tissue-specific self-antigens are ectopically expressed within the thymus and play an important role in the induction of central tolerance. Insulin is expressed in both pancreatic islets and the thymus and is considered to be the primary antigen for type 1 diabetes. Here, we report the role of the insulin transactivator MafA in the expression of insulin in the thymus and susceptibility to type 1 diabetes.

RESEARCH DESIGN AND METHODS

The expression profiles of transcriptional factors (Pdx1, NeuroD, Mafa, and Aire) in pancreatic islets and the thymus were examined in nonobese diabetic (NOD) and control mice. Thymic Ins2 expression and serum autoantibodies were examined in Mafa knockout mice. Luciferase reporter assay was performed for newly identified polymorphisms of mouse Mafa and human MAFA. A case-control study was applied for human MAFA polymorphisms.

RESULTS

Mafa, Ins2, and Aire expression was detected in the thymus. Mafa expression was lower in NOD thymus than in the control and was correlated with Ins2 expression. Targeted disruption of MafA reduced thymic Ins2 expression and induced autoantibodies against pancreatic islets. Functional polymorphisms of MafA were newly identified in NOD mice and humans, and polymorphisms of human MAFA were associated with susceptibility to type 1 diabetes but not to autoimmune thyroid disease.

CONCLUSIONS

These data indicate that functional polymorphisms of MafA are associated with reduced expression of insulin in the thymus and susceptibility to type 1 diabetes in the NOD mouse as well as human type 1 diabetes.
Acute Pancreatitis in Type 2 Diabetes Treated With Exenatide or Sitagliptin
Authors: Garg Rajesh , Chen William , Pendergrass Merri
Published: August 2010

OBJECTIVE

Cases of acute pancreatitis have been reported in association with exenatide, sitagliptin, and type 2 diabetes without use of these medications. It remains unknown whether exenatide or sitagliptin increase the risk of acute pancreatitis.

RESEARCH DESIGN AND METHODS

A retrospective cohort study of a large medical and pharmacy claims database was performed. Data for 786,656 patients were analyzed. Cox proportional hazard models were built to compare the risk of acute pancreatitis between diabetic and nondiabetic subjects and between exenatide, sitagliptin, and control diabetes medication use.

RESULTS

Incidence of acute pancreatitis in the nondiabetic control group, diabetic control group, exenatide group, and sitagliptin group was 1.9, 5.6, 5.7, and 5.6 cases per 1,000 patient years, respectively. The risk of acute pancreatitis was significantly higher in the combined diabetic groups than in the nondiabetic control group (adjusted hazard ratio 2.1 [95% CI 1.7–2.5]). Risk of acute pancreatitis was similar in the exenatide versus diabetic control group (0.9 [0.6–1.5]) and sitagliptin versus diabetic control group (1.0 [0.7–1.3]).

CONCLUSIONS

Our study demonstrated increased incidence of acute pancreatitis in diabetic versus nondiabetic patients but did not find an association between the use of exenatide or sitagliptin and acute pancreatitis. The limitations of this observational claims-based analysis cannot exclude the possibility of an increased risk.
Mapping the North: The UpdatedNorth Circumpolar RegionMap by the Atlas of Canada
Authors: Kramers R. Eric , Murray Andrew
Published: August 2010

For more than 100 years the Atlas of Canada, published by Natural Resources Canada, has told the story of Canada through geographical and historical maps reflecting the country's social, environmental, and economic diversity. The Atlas' original North Circumpolar Region map was published in 1990; revisions followed in 1996, 1997, and 2004. The latest edition, published in 2008 for the International Polar Year, reflects significant progress in data collection, data integration, and cartographic methods. The revision process presented a number of challenges that led to innovative cartographic and technical solutions. This article focuses on some of the objectives, challenges, and methods associated with undersea and terrestrial relief, bathymetry, drainage features, sea ice, glaciers, and ice shelves.
Bus Network Planning for Transfers and the Network Effect in Melbourne, Australia
Authors: Currie Graham , Loader Chris
Published: August 2010

Although passengers dislike transferring, efficient transit systems should facilitate transfers to provide auto-competitive citywide access. This paper reviews bus transfer behavior in Melbourne, Australia, to understand causal factors. It also explores network effects: high ridership associated with frequent services or simple (grid) networks or both. Half of bus users make transfers, mostly to rail. The number of tram and bus transfers is generally low; however, in inner and central business district areas where trams run, they dominate. The young, students, males, commuters, and riders with periodical or full-fare tickets have high bus transfer rates. Middle-aged and older groups, off-peak riders, riders on shopping trips, and concession ticket holders have lower rates. Weekday peak hour commuters have high transfer rates. Frequent or longer-distance bus route types, simpler or straight route alignments, commuter services, and routes that require transfers have high transfer rates. Schedule coordination with rail increases transfer rates, but only a little. A modest but significant relationship (R2 = .25) between the volume of transfer trips and average service frequency was shown. High transfer volumes occur where at least one route has a frequency of 10 min or better. Current bus plans propose a 15-min-based grid route network. These findings suggest that major routes need at least 10-min headways to generate high transfer rates. A high bus transfer subnetwork was identified with features consistent with the network effect; however, conclusive proof of the network effect remains elusive. In simple terms the network effect, though intriguing, remains an unsubstantiated theory that informs good practice but should be treated with caution when applied in the real world.
Developing a Bus Rapid Transit Strategic Plan for San Jose and Silicon Valley, California
Authors: Wong Corey , Fisher Steven
Published: August 2010

The Santa Clara Valley Transportation Authority (VTA) of Santa Clara County, California, recently developed a bus rapid transit (BRT) strategic plan to establish a framework for BRT implementation, provide guidance on policy issues, and serve as a vehicle for community interaction. A multiphased evaluation process was applied to identify the most feasible near-term BRT corridors within the county, develop operating plans and infrastructure strategies, and select the preferred BRT operating and infrastructure strategies. Three corridors were prioritized for near-term BRT. The preferred operating strategy was forecast to generate 25,000 more daily riders in 2030 than the no-project scenario and showed promise to improve mobility along key arterials around San Jose, California. The BRT strategic plan was adopted by the VTA board of directors in mid-2009. VTA is moving forward with engineering and desk work on the three near-term corridors. This paper discusses the approach and processes adopted in the strategic plan that moved the BRT discussion forward. Cities in a similar incipient stage of BRT planning can heed key lessons learned to facilitate their own activities: establishing a coherent BRT vision and development process internally before reaching out to stakeholders, involving operations staff early in the development process to foster buy-in, holding frank discussions on maintaining local overlay service, and applying a specific process to develop a signature and unique BRT brand and service.
Select Bus Service on Bx12 in New York City: Bus Rapid Transit Partnership of New York City DOT and Metropolitan Transportation Authority New York City Transit
Authors: Barr Joseph E. , Beaton Eric B. , Chiarmonte Joseph V. , Orosz Theodore V.
Published: August 2010

Cities throughout the United States and around the world have found bus rapid transit (BRT) to be a popular and cost-effective way to improve their public transit systems quickly. On June 29, 2008, the New York City Department of Transportation and the Metropolitan Transportation Authority New York City Transit inaugurated service on the Bx12 select bus service (SBS), the first phase of BRT in New York City. The project included enhanced bus lanes, off-board fare collection (a first in New York City), and transit signal priority, along with enhanced stations, improved customer information, and distinctive branding. The Bx12 SBS leveraged existing resources to allow implementation to take place quickly (within 1 year) and at relatively low cost (approximately $10 million). The Bx12 SBS project focused on improving bus speed and reliability as well as on making bus service more attractive to customers. Results showed a 20% reduction in travel time along the corridor and an 11.5% increase in ridership in the corridor. A total of 98% of bus customers surveyed described themselves as satisfied or very satisfied with the service. This project was the result of an ongoing partnership between the two agencies; its success depended on the strong relationship between the executive leadership and the agency staff. Implementation of this project has led to a demand for rapid expansion of BRT in New York City, paving the way for the implementation of additional planned BRT routes as well as the development of a comprehensive plan for future BRT services.
Iterative Proportional Fitting Procedure to Determine Bus Route Passenger Origin–Destination Flows
Authors: McCord Mark R. , Mishalani Rabi G. , Goel Prem , Strohl Brandon
Published: August 2010

The advent of automatic passenger counter (APC) technologies is resulting in the collection of comprehensive boarding and alighting data on an ongoing basis across transit networks. The availability of APC data offers a new opportunity to determine origin–destination (O-D) flows on a frequent and comprehensive basis. In this paper, the performance of a simple procedure for route-level O-D flow determination requiring only boarding and alighting data is investigated. Specifically, the performance of the iterative proportional fitting (IPF) procedure used with a null base matrix is examined on the basis of a field experiment in which true O-D flows are observed. Because of the noninformative nature of the null matrix, using the IPF procedure with the null matrix as its input base may not be expected to produce good results. In a comparison of empirical results with those produced by other benchmark procedures, the IPF–null procedure is found to perform surprisingly well. The quality of the resulting matrices appears to be roughly similar to that of matrices derived from an onboard survey, the benchmark for what has been achieved in practice, but at much higher cost. The results indicate that much can be gained from using readily available APC data, even when the simple IPF–null procedure is applied. Moreover, using the better base obtained from an onboard survey with the IPF procedure improved performance, but less markedly compared with use of the null base; this difference indicates that combining onboard survey information with APC data provides a better O-D matrix than what can be derived from an onboard survey alone, even when the simple IPF procedure is used.
Space Requirements for Wheeled Mobility Devices in Public Transportation: Analysis of Clear Floor Space Requirements
Authors: D'Souza Clive , Steinfeld Edward , Paquet Victor , Feathers David
Published: August 2010

Recent research on the anthropometry of wheeled mobility devices and their users (n = 369) indicates that the current dimensions for clear floor area prescribed in U.S. accessibility standards for transportation are inadequate for accommodating many users of wheeled mobility devices, especially those who use power chairs and scooters. The current report presents anthropometry data for determining the dimensions of clear floor area on the basis of occupied device length and width to achieve a specified level of physical accommodation. The implications of the findings and the need to revise guidelines for accessible public transportation systems are discussed. The transportation industry as well as mobility device manufacturers, vendors, and prescribers should understand the limitations of current standards and become involved in the dialogue about how to improve them.
Effects of Basic Rural Paratransit Characteristics on Organizational Culture
Authors: Monast Kai , Downs Darcy
Published: August 2010

The purpose of this research is to determine if the basic characteristics of rural paratransit systems influence their organizational culture. “Organizational culture” is defined in this research as a pattern of shared basic assumptions for solving problems that is considered the correct way to perceive, think, and feel in relation to those problems. Eight categories of organizational culture specific to paratransit systems—including efficiency, customer focus, availability to the general public, dedication to human service agencies, growth, maintenance of the status quo, business, and charity—were explored. The survey was distributed to managers of paratransit agencies with similar funding sources and the same basic goal of providing community mobility. Respondents completed the survey by ranking the statements in each question in order of importance. Respondent rankings were analyzed with the use of basic characteristics of paratransit systems, including organization type, scheduling software, and system size. All organizational culture categories were influenced by at least one basic paratransit characteristic. The study concludes that organizational culture varies significantly according to the characteristics of a paratransit agency. The study recommends that funding sources develop clear expectations of organizational culture, effectively convey these expectations, and measure how successfully the expectations were fulfilled. The results also suggest that standard industry training is necessary to establish consistent organizational cultures among different paratransit systems. Finally, all plans to improve the performance of paratransit systems should include an assessment of organizational culture.
Classifying Rural and Small Urban Transit Agencies
Authors: Ripplinger David
Published: August 2010

Rural and small urban transit agencies are classified into peer groups by the hierarchical cluster analysis and data from the Rural National Transit Database. The objective is to provide a basis for the comparison of individual agency performance with peer group performance as well as econometric analysis between and within peer groups. Rural and small urban transit agencies are first assigned to three groups by service provided: demand–response, fixed-route, and demand–response and fixed-route service. A fourth group is created to accommodate the many transit agencies providing demand–response service that did not report vehicle hour data. The four groups are then clustered by using vehicle mile, vehicle hour (when available), and fleet size variables. Operating statistics for each cluster by group are presented. The process for comparing individual agency performance with its respective cluster is described. The Rural National Transit Database demonstrates its usefulness as a consistent, uniform national data set. However, additional service area information would accommodate clustering based on exogenous, as opposed to endogenous, variables, as necessary with the current data set.
Impact of Rumble Strips on Collision Reduction on Highways in British Columbia, Canada: Comprehensive Before-and-After Safety Study
Authors: Sayed Tarek , deLeur Paul , Pump John
Published: August 2010

A comprehensive before-and-after study evaluated the safety impacts associated with application of shoulder and centerline rumble strips on highways in British Columbia, Canada. Data were collected for three groups of sites: treatment group, comparison group, and reference group. The treatment group included 47 sites belonging to two highway classes: an undivided, rural two-lane arterial (RAU2) and a divided, rural four-lane freeway. A total of 225 sites were used to establish a comparison group for the treatment sites based on implementation year for the treatment site and the highway class. The comparison group was used to correct for the confounding factors of history and maturation. Six reference groups were used; they correspond to the two highway classes and three time periods (2000 to 2002, 2001 to 2003, and 2002 to 2004). Collision prediction models developed from the reference groups were used to correct for the regression to the mean and to account for the changes in traffic volumes in the before-and-after periods. Overall, the results showed that shoulder and centerline rumble strips can significantly reduce severe collisions and specific collision types: (a) the installation of rumble strips reduced all injury collisions by a statistically significant 18.0%; (b) shoulder rumble strips reduced off-road right collisions by a statistically significant 22.5%; and (c) centerline rumble strips (RAU2 sites) showed a statistically significant reduction of 29.3% in off-road left and head-on collisions. RAU2 sites with both centerline and shoulder rumble strips showed a statistically significant reduction of 21.4% in off-road right, off-road left, and head-on collisions combined.
Logistic Models in Crash Severity Classification Based on Road Characteristics
Authors: Nowakowska Marzena
Published: August 2010

The influence on traffic safety of certain road geometric parameters and characteristics is identified. The research involves real data about multivehicle accidents without pedestrians on nonurban roads for a chosen region of Poland. The accident data were integrated with the road data for the accident location by means of the author's computer programs. Logistic regression in the form of the proportional odds ratio model and continuation ratio logits was investigated in the analysis. The threat on the road is represented by accident severity, which is the ordered response variable subject to the classification task. The set of explanatory variables consists of the road design elements (e.g., vertical and horizontal curves) as well as information on road access (e.g., bus stops, public and private access lanes) and land use (e.g., gas stations, parking places). The modeling results indicate that the following features have a statistically significant influence on accident severity: the type of shoulders on both sides of a roadway, area type, pedestrian sidewalks, and the presence or absence of intersections.
Exploratory Study of Mechanisms by Which Exposure Influences Accident Occurrence
Authors: Elvik Rune
Published: August 2010

A study explores mechanisms by which exposure influences accident occurrence. The study is based on a previous one in which exposure was defined as the occurrence of specific events that represent an opportunity for an accident to happen. Four such events were considered: encounters, simultaneous arrivals in intersections or at pedestrian crossing facilities, lane changes, and braking. A review is done of some studies that permit the shape of the relationship between the number of events and the probability of accident occurrence to be determined. It is found that, in general, the rate of accidents per event falls sharply as the number of events increases. This finding can be interpreted as a learning curve: the more often road users encounter a specific event, the more skillful they become in recognizing and controlling the risks involved in that event. A measure of learning efficiency is proposed, and it is shown that learning efficiency varies between different types of events. It is suggested that the complexity, controllability, and predictability of an event influence learning efficiency. More complex, less controllable, and less predictable events reduce learning efficiency because these events are associated with cognitive overload and violation of road user expectations. Examples are given of events of varying degrees of complexity, controllability, and predictability. Another mechanism by which events involving conflict or physical contact between road users become recorded as accidents is incompatibility, which refers to differences in the kinetic energy produced by different types of vehicles and the degree to which they protect road users from impact.
Implementation Road Map for In-Vehicle Safety Systems in China
Authors: Lu Meng , Wevers Kees , Wang Jianqiang
Published: August 2010

A major side effect of the economic boom in China is a high number of traffic accidents. Besides traditional measures, such as legislation, regulation, education, and road infrastructure, road safety can be improved through the implementation of in-vehicle driving assistance systems as part of intelligent transportation systems. In this study, the traffic and transport situation and trends in China are analyzed, and the need for improving traffic safety through in-vehicle systems is addressed. Furthermore, potential solutions for enhancing road traffic safety by using in-vehicle driving assistance systems are investigated, and the implementation of such systems is priority-ranked by using a mathematical approach, gray relational analysis. In addition, a road map for the implementation of safety-oriented in-vehicle systems in China is proposed and discussed.
Perceptual Measures to Influence Operating Speeds and Reduce Crashes at Rural Intersections: Driving Simulator Experiment
Authors: Montella Alfonso , Aria Massimo , D'Ambrosio Antonio , Galante Francesco , Mauriello Filomena , Pernetti Mariano
Published: August 2010

The aim of this paper is to investigate, by means of a dynamic driving simulator experiment, the behavior of road users at rural intersections in relation to perceptual measures designed for increasing hazard detection. In the experiment 10 configurations of tangents were tested: Alt1, base tangent; Alt2, four-leg base intersection; Alt3, intersection with reduced sight distance; and Alt4 through Alt10, intersections with perceptual treatments. The Virtual Environment for Road Safety high-fidelity dynamic-driving simulator, operating at the Technology Environment Safety Transport Road Safety Laboratory located in Naples, Italy, was used. Analysis of the results used two approaches: (a) explorative description of data by cluster analysis and (b) inferential procedures about population using statistical tests. Results showed that the speed behavior in the tangents was significantly affected by the presence of the intersections and by the perceptual treatments. Intersections without perceptual treatments significantly affected driver speeds in the 250 m preceding the intersection. Perceptual treatments helped the driver to detect the intersection earlier and to slow down. Dragon teeth markings, colored intersection area, and raised median island performed better than the other perceptual treatments. They produced significant average speed reduction in the 150 m preceding the intersection ranging between 16 km/h and 23 km/h. Study results support real-world implementation of perceptual measures in rural intersections because they are low-cost, fast implementation measures with a high potential to be cost-effective.
Evaluation of Effectiveness of Converging Chevron Pavement Markings in Reducing Speed on Freeway Ramps
Authors: Hunter Michael , Boonsiripant Saroch , Guin Angshuman , Rodgers Michael O. , Jared David
Published: August 2010

Converging chevron pavement markings have recently seen rising interest in the United States as a means to reduce speeds at high-speed locations and improve safety performance. This paper reports on an investigation into the effectiveness of chevron markings in reducing vehicle speeds on two-lane freeway-to-freeway directional ramps in Atlanta, Georgia. The evaluation is based on a statistical comparison at preselected sites of speeds before and after the installation of the chevron markings. The analysis focuses on the effect of converging chevrons over the range of speed percentiles and on the mean speed. The analysis indicates that chevrons have a minimal effect on vehicle speeds, with drivers adjusting back to their previous speeds as they acclimate to the treatment. The effect of the chevrons’ treatments on speed tended to be most pronounced immediately after the chevron implementation. However, by the 9th month after implementation the magnitude of the effect dropped to under 1 to 2 mph for the mean speed and most vehicle speed percentiles. Although this result does not necessarily imply that the chevron treatment is not a meaningful safety treatment, any safety benefits are not likely to result from a general decrease in speeds.
Guidance on Design and Application of Rumble Strips
Authors: Torbic Darren J. , Hutton Jessica M. , Bokenkroger Courtney D. , Bauer Karin M. , Donnell Eric T. , Lyon Craig , Persaud Bhagwant
Published: August 2010

Many transportation agencies use shoulder rumble strips to address the problem of single-vehicle run-off-the-road crashes by alerting inattentive or drowsy motorists that their vehicles have drifted out of the travel lane. The application of rumble strips has expanded to include the installation of centerline rumble strips along the centerlines of undivided highways to reduce head-on and opposite-direction sideswipe crashes. Installing rumble strips along either the shoulder or centerline without considering the effect on other highway users (i.e., bicyclists and motorcyclists) may lead to unintended consequences. This research addresses a number of safety issues: (a) the safety effectiveness of shoulder rumble strips on different roadway types, (b) the safety effectiveness of shoulder rumble strip placement relative to the edgeline, (c) the safety effectiveness of centerline rumble strips on different roadway types, and (d) the safety effectiveness of centerline rumble strips along horizontal curves and tangents. The safety evaluations considered all severity levels (total crashes) and fatal and injury crashes. Statistical models for predicting noise levels in the passenger compartment of a vehicle for use in designing rumble strip patterns were also developed. The results of this research were combined with results from previous research to address important policy issues for transportation agencies to consider in the design and application of shoulder and centerline rumble strips.
Do Pedestrian Countdown Signals Influence Vehicle Speeds?
Authors: Nambisan Shashi S. , Karkee Ganesh J.
Published: August 2010

The effects of pedestrian countdown signals on speeds of approaching vehicles as a function of the distance of the vehicle upstream of the intersection and the signal display are reported here. The analyses used mean speeds of vehicles on two segments immediately upstream of the stop bar and also during different indications of the pedestrian signal head (pedestrian “Walk” and pedestrian flashing “Don't Walk” signal with the time remaining in seconds to cross the street for the following intervals: greater than 15 s, 15 s to 10 s, 10 s to 5 s, and less than 5 s). Appropriate tests were performed to determine the statistical significance of the differences in observed mean speeds for each of these scenarios. Vehicle speeds were greater on the segment closer to the intersection than on the segment farther away. The speeds were also greater during the pedestrian countdown timer and flashing “Don't Walk” displays on the pedestrian signal head than when the pedestrian “Walk” signal and the countdown timer were displayed. All results were statistically significant at a 95% level of confidence except one, which had a 93% level of confidence. Results do not indicate that speeds are affected by the actual numeric displays on the countdown timer.
Effects of Dynamically Activated Emergency Vehicle Warning Sign on Driver Behavior at Urban Intersections
Authors: Savolainen Peter T. , Datta Tapan K. , Ghosh Indrajit , Gates Timothy J.
Published: August 2010

Emergency vehicles are subjected to substantial risks when traveling through urban signalized intersections, particularly when the cross street traffic is provided with a green signal indication. Much of this risk is due to a lack of awareness of the approaching emergency vehicles on the part of the cross street traffic. To mitigate this problem, a dynamically activated emergency vehicle alert system was developed to provide an additional visual cue to motorists of an impending emergency vehicle's approach. The alert system consists of an LED case sign, mounted near the curb line adjacent to a traffic signal, which displays an emergency vehicle symbol when activated by a transmitter installed in the emergency vehicle as it approaches an intersection. A before-and-after evaluation of these warning signs was conducted at five test intersections in two suburban communities near Detroit, Michigan. The results showed that the alert system significantly improved driver awareness and behavior at all study locations as determined by comparing various measures of effectiveness. Overall, the proportion of drivers who yielded the right-of-way to an approaching emergency vehicle increased from 77.1% before installation of the warning signs to 96.6% after installation. Drivers also tended to yield sooner when the alert system was in use, and when violations of the emergency vehicle right-of-way did occur, they generally happened sooner.