8,036 research outputs found
Bus Rapid Transit: A Handbook for Partners, MTI Report 06-02
In April 2005, the Caltrans Division of Research and Innovation (DRI) asked MTI to assist with the research for and publication of a guidebook for use by Caltrans employees who work with local transit agencies and jurisdictions in planning, designing, and operating Bus Rapid Transit (BRT) systems that involve state facilities. The guidebook was also to assist to transit operators, local governments, community residents, and other stakeholders dealing with the development of BRT systems. Several areas in the state have experienced such projects ( San Diego , Los Angeles , San Francisco , and Alameda County ) and DRI wished to use that experience to guide future efforts and identify needed changes in statutes, policies, and other state concerns. Caltrans convened a Task Team from the Divisions of Research and Innovation, Mass Transportation, and Operations, together with stakeholders representing many of those involved with the BRT activities around the state. Prior to MTI’s involvement, this group produced a white paper on the topic, a series of questions, and an outline of the guidebook that MTI was to write. The MTI team conducted case studies of the major efforts in California, along with less developed studies of some of the other BRT programs under development or in early implementation phases around the state. The purpose was to clarify those issues that need to be addressed in the guidebook, as well as to compile information that would identify items needing legislative or regulatory action and items that Caltrans will need to address through district directives or other internal measures. A literature scan was used to develop a bibliography for future reference. The MTI team also developed a draft Caltrans director’s policy document, which provides the basis for Caltrans’ actions. This ultimately developed to be a project within a project. MTI submitted a draft document to Caltrans as a final product from the Institute. Task team members and Caltrans staff and leadership provided extensive review of the draft Bus Rapid Transit: A Handbook for Partners. Caltrans adopted a new Director’s Policy and published the document, BRT Caltrans. The MTI “wraparound” report presented below discusses in more detail the process that was followed to produce the draft report. The process was in many ways as much a project as the report itself
California Border Zone Land Transportation Issues: NAFTA II, MTI Report 01-06
The Mineta Transportation Institute at San José State University conducted this study to review the issues, impacts, implications, and opportunities for improved California-Baja California border area land transportation. The study reviews current conditions, previously identified issues, and, in consultation with Caltrans District 11 officials and others, developed an ultimate listing of seven issues for detailed study as follows: (1) public transportation at the border; (2) cross-broder Americans with Disabilities Act interface; (3) California highway access to Tijuana International Airport; (4) Clean Air Act compliance; (5) General Services Administration off-site authority; (6) southbound inspection requirement; and (7) pipelines or other stationary facilities. As the study proceeded several topics of immediate concern were identified and relayed to the California Department of Transportation (Caltrans) as four recommendations. Observations and findings relating to the above seven issues are summarized and fifteen recommendations concerning them are presented
Impact of the North American Free Trade Agreement on Transportation in the Border Areas of the United States: With Emphasis on the California-Mexico Border, MTI Report 99-02
The Norman Y. Mineta International Institute for Surface Transportation Policy Studies (IISTPS) at San Jos. State University conducted this study to identify impacts of the North American Free Trade Agreement (NAFTA) on transportation in the U.S. border areas, with emphasis on the California-Baja California border zone. Major focus was placed on the identification of recommendations to the California Department of Transportation (Caltrans) to improve the ability of that organization to identify and accelerate short-term implementation of the needed infrastructure improvements. The subjects covered include a literature review, identification of issues in the form of questions, discussion of the questions, and categorization of the questions as: 1. Issues not appropriate for further consideration in this study, 2. Issues recommended for action at a later date, 3. Issues addressed by others, and 4 Issues recommended for short-term action. A summary of the categorization of all the questions appears in a matrix at the end of Chapter 4, with the details presented in the body of the report. Finally, Category 4 issues, those recommended for action, are further addressed with recommendations and a brief action plan, if appropriate. The appendices include a review of work in progress, and several reference documents
Non-Pricing Methods to Optimize High Occupancy Vehicle Lane Usage, MTI Report 01-11
The Mineta Transportation Institute) at San José State University conducted this study to review the issues and implications involved in the project in question. Twenty-four potential HOV facility user groups were identified. Through a ranking process, seven of these groups were selected for further study in phase one. The project team made the following preliminary conclusions as to the suitability of each group to use HOV facilities and recommended whether each group should be included in the phase two study to refine these findings and develop implementation strategies. 1. As the result of 1998 legislation, which includes sunset provisions, electric vehicles and other ILEVs, ULEVs, and SULEVs have recently been included in users of HOV facilities. This legislation should be reviewed in phase two to determine if the sunset provisions should be extended. 2. The identified negatives for including light delivery trucks outweigh any identified positives. Unless new evidence surfaces, this group should be dropped from the study. 3. Radio dispatched vehicles are strong candidates, inclusion should result in improved public transportation services. Phase two study of possible enabling legislation should consider sunset provisions to encourage future fleet conversion to vehicles using alternative fuels. 4. Inclusion of EPA certified high mileage vehicles and vehicles using alternative fuels could encourage use of these vehicles with beneficial impacts on air quality and fuel consumption. Possible significant problems of capacity, identification of users, and police monitoring and enforcement should be studied in phase two. 5. Deadheading transit and charter buses appear to be worthy candidates and should be studied further. School buses, because of inherent problems, should not be considered unless significant warrants surface. 6. There does not appear to be any advantage in including light service trucks (utility, maintenance, etc.). 7. There is no compelling reason to change existing conditions regarding enforcement and emergency vehicles
Tropical cyclone motion and surrounding parameter relationships
December 1975.Includes bibliographical references.Sponsored by NOAA 04-5-022-14
Growth Response of Kenhy Fescue to Nitrogen Fertilizer
Kenhy fescue is a new, improved variety of tall fescue which has recently been released by the University of Kentucky Agricultural Experiment Station and the U.S.D.A. Agricultural Research Service (see University of Kentucky publication AGR-60, Kenhy A New Tall Fescue Variety ). Seed of this variety should become available to farmers in limited quantities in the summer 1977. The purpose of this report is to provide information on how this newly developed fescue variety produces as affected by time and rate of nitrogen application
Alternative Computational Protocols for Supercharging Protein Surfaces for Reversible Unfolding and Retention of Stability
Bryan S. Der, Ron Jacak, Brian Kuhlman, Department of Biochemistry and Biophysics, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States of AmericaChristien Kluwe, Aleksandr E. Miklos, Andrew D. Ellington , Center for Systems and Synthetic Biology, University of Texas at Austin, Austin, Texas, United States of AmericaChristien Kluwe, Aleksandr E. Miklos, George Georgiou, Andrew D. Ellington, Institute for Cellular and Molecular Biology, University of Texas at Austin, Austin, Texas, United States of AmericaAleksandr E. Miklos, Andrew D. Ellington , Applied Research Laboratories, University of Texas at Austin, Austin, Texas, United States of AmericaSergey Lyskov, Jeffrey J. Gray, Department of Chemical and Biomolecular Engineering, Johns Hopkins University, Baltimore, Maryland, United States of AmericaBrian Kuhlman, Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States of AmericaReengineering protein surfaces to exhibit high net charge, referred to as “supercharging”, can improve reversibility of unfolding by preventing aggregation of partially unfolded states. Incorporation of charged side chains should be optimized while considering structural and energetic consequences, as numerous mutations and accumulation of like-charges can also destabilize the native state. A previously demonstrated approach deterministically mutates flexible polar residues (amino acids DERKNQ) with the fewest average neighboring atoms per side chain atom (AvNAPSA). Our approach uses Rosetta-based energy calculations to choose the surface mutations. Both protocols are available for use through the ROSIE web server. The automated Rosetta and AvNAPSA approaches for supercharging choose dissimilar mutations, raising an interesting division in surface charging strategy. Rosetta-supercharged variants of GFP (RscG) ranging from −11 to −61 and +7 to +58 were experimentally tested, and for comparison, we re-tested the previously developed AvNAPSA-supercharged variants of GFP (AscG) with +36 and −30 net charge. Mid-charge variants demonstrated ~3-fold improvement in refolding with retention of stability. However, as we pushed to higher net charges, expression and soluble yield decreased, indicating that net charge or mutational load may be limiting factors. Interestingly, the two different approaches resulted in GFP variants with similar refolding properties. Our results show that there are multiple sets of residues that can be mutated to successfully supercharge a protein, and combining alternative supercharge protocols with experimental testing can be an effective approach for charge-based improvement to refolding.This work was supported by the Defense Advanced Research Projects Agency (HR-0011-10-1-0052 to A.E.) and the Welch Foundation (F-1654 to A.E.), the National Institutes of Health grants GM073960 (B.K.) and R01-GM073151 (J.G. and S.L.), the Rosetta Commons (S.L.), the National Science Foundation graduate research fellowship (2009070950 to B.D.), the UNC Royster Society Pogue fellowship (B.D.), and National Institutes of Health grant T32GM008570 for the UNC Program in Molecular and Cellular Biophysics. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.Center for Systems and Synthetic BiologyCellular and Molecular BiologyApplied Research LaboratoriesEmail: [email protected]
Simultaneous Determination of the Predominant Hyperforins and Hypericins in St. John's Wort (Hypericum perforatum L.) by Liquid Chromatography
Hypericin and hyperforin are believed to be among the active constituents in common St. John's wort (Hypericum perforatum L.). Presently, dietary supplements are generally standardized to contain specified levels of hypericin and hyperforin, and the related compounds, pseudohypericin and adhyperforin. A rapid method was developed for simultaneous determination of these 4 active constituents by liquid chromatography (LC). A 1 g portion of dried, finely ground leaf/flower sample is extracted with 20 mL methanol for 2 h. A 0.6 mL aliquot of the crude extract is combined with 5.4 mL acetonitrile-methanol (9 + 1) and passed through a mixed solid-phase cleanup column. The eluate is examined by LC for hyperforin, adhyperforin, hypericin, and pseudohypericin on a Hypersil reversed-phase column by using simultaneous ultraviolet (284 nm) and fluorescence detection (excitation, 470 nm; emission, 590 nm). The compounds are easily separated isocratically within 8 min with a mobile phase of acetonitrile-aqueous 0.1M triethylammonium acetate (8 + 2). Average recoveries of hyperforin and adhyperforin were 101.9 and 98.4%, respectively, for 3 sample mixtures containing concentrations ranging from approximately 0.2 to 1.5% combined hyperforins per gram dry weight. Average relative standard deviation (RSD) values for hyperforin and adhyperforin for all 3 mixtures were 18.9 and 18.0%, respectively. Average recoveries of hypericin and pseudohypericin were 88.6 and 93.3% respectively, from 3 sample mixtures containing concentrations ranging from approximately 0.2 to 0.4% combined hypericins per gram dry weight. Average RSD values for hypericin and pseudohypericin for all 3 mixtures were 3.8 and 4.2%, respectively. C ommon St. John's wort (Hypericum perforatum L.) is a perennial species of the Hypericaceae family, native to Europe. Dietary supplements and other herbal preparations produced from the leaves and flowers of St. John's wort have gained popularity in the United States in recent years (1, 2). A recent overview of 23 controlled clinical trials concluded that St. John's wort was more effective than a placebo for the treatment of mild depression (3). Commercial extracts from the leaves and flowers are also being investigated for anticancer and antiviral activities (4). The predominant napthodianthrone derivatives, hypericin and pseudohypericin, and the phloroglucine derivatives, hyperforin and adhyperforin, are among the compounds presently being investigated for their biological activities. Standardized dietary supplements of St. John's wort currently contain from 0.3 to 0.5% hypericin(s), and/or approximately 3.0% hyperforin(s). In 1998, St. John's wort herbal products showed exceptional sales growth, increasing nearly 3000% from 1997 to 1998 (2). Several recent papers on the chemical analysis of St. John's wort have provided the means to measure many of the predominant chemical constituents from diluted, crude extracts (5-12). In general, samples were extracted and filtered, or liquid-liquid extraction was used to remove chlorophylls and other pigments. The use of mixed solid-phase (MSP) cleanup columns has been reported recently in the literature. Wilson and Romer (13) developed a proprietary cleanup column consisting of a mixture of reversed-phase, ion-exclusion, and ion-exchange packing materials used for cleanup of extracts of corn, cottonseed, rice, mixed feeds, and a variety of nuts in the determination of aflatoxins. Similarly, Tacke and Casper (14) developed a C 18 -alumina (1 + 3) MSP cleanup column for wheat extracts in the determination of deoxynivalenol. The following method was developed to provide a rapid, inexpensive, MSP cleanup with simultaneous determination of the 4 compounds of greatest current interest, hypericin, hyperforin, pseudohypericin, and adhyperforin from flower and leaf mixtures of St. John's wort
Non-geometric flux vacua, S-duality and algebraic geometry
The four dimensional gauged supergravities descending from non-geometric
string compactifications involve a wide class of flux objects which are needed
to make the theory invariant under duality transformations at the effective
level. Additionally, complex algebraic conditions involving these fluxes arise
from Bianchi identities and tadpole cancellations in the effective theory. In
this work we study a simple T and S-duality invariant gauged supergravity, that
of a type IIB string compactified on a orientifold with
O3/O7-planes. We build upon the results of recent works and develop a
systematic method for solving all the flux constraints based on the algebra
structure underlying the fluxes. Starting with the T-duality invariant
supergravity, we find that the fluxes needed to restore S-duality can be simply
implemented as linear deformations of the gauge subalgebra by an element of its
second cohomology class. Algebraic geometry techniques are extensively used to
solve these constraints and supersymmetric vacua, centering our attention on
Minkowski solutions, become systematically computable and are also provided to
clarify the methods.Comment: 47 pages, 10 tables, typos corrected, Accepted for Publication in
Journal of High Energy Physic
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