Finishing the euchromatic sequence of the human genome

The sequence of the human genome encodes the genetic instructions for human physiology, as well as rich information about human evolution. In 2001, the International Human Genome Sequencing Consortium reported a draft sequence of the euchromatic portion of the human genome. Since then, the international collaboration has worked to convert this draft into a genome sequence with high accuracy and nearly complete coverage. Here, we report the result of this finishing process. The current genome sequence (Build 35) contains 2.85 billion nucleotides interrupted by only 341 gaps. It covers ∼99% of the euchromatic genome and is accurate to an error rate of ∼1 event per 100,000 bases. Many of the remaining euchromatic gaps are associated with segmental duplications and will require focused work with new methods. The near-complete sequence, the first for a vertebrate, greatly improves the precision of biological analyses of the human genome including studies of gene number, birth and death. Notably, the human enome seems to encode only 20,000-25,000 protein-coding genes. The genome sequence reported here should serve as a firm foundation for biomedical research in the decades ahead

Effect of passenger encumbrance and mobility aid use on dwell time variability in low-floor transit vehicles

Public transit serves users with a broad range of physical capabilities and design needs. However information about the operational effects of diverse users interacting with the transit system is scarce. This paper examined the occurrence and effects of boarding and alighting passengers with mobility aids (wheelchairs, scooters, walkers and canes), or with large items (carts, strollers, bicycles, or carrying an infant) on bus stop dwell time in a fixed-route bus service. On-board video data from low-floor public transit buses serving Ann Arbor, Michigan were used from 199 bus stops with at least one passenger boarding or alighting with a mobility aid or encumbered with a large item, and an additional 1642 bus stops without any mobility aids or encumbrances. A sequence of linear regression models examined the relationship between dwell time and the addition of variables representing passengers with mobility aids and encumbrances, and use of the on-vehicle access ramp, beyond explanatory variables typically used in dwell time analysis. Accounting for passengers boarding/alighting with mobility aids and encumbrances (p \u3c 0.001) and use of the access ramp (p \u3c 0.001) increased the variance explanation of a dwell time model based on boarding passengers by fare payment, alighting passengers by door use, and passenger load from 46% to 56%. Results indicate distinct patterns in the durations for boarding and alighting by passengers with vs. without mobility aids and encumbrances, and when a ramp is used by wheeled mobility users vs. ambulatory passengers with walking aids. The findings suggest that accounting for the presence of passengers with mobility aids or encumbrances and ramp use in dwell time analyses could help transit operators make their service operationally more efficient and inclusive for all passengers and encourage more use of fixed-route transit among individuals with disabilities

Space Requirements for Wheeled Mobility Devices in Public Transportation

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 transit bus interior configuration on performance of wheeled mobility users during simulated boarding and disembarking

The emergence of low-floor bus designs and related regulatory standards in the U.S. have resulted in substantial improvements in public transit accessibility. However, passengers using wheeled mobility devices still experience safety concerns and inefficiencies in boarding, disembarking, and interior circulation on low-floor buses. This study investigates effects of low-floor bus interior configuration and passenger crowding on boarding and disembarking efficiency and safety. Users of manual wheelchairs (n = 18), powered wheelchairs (n = 21) and electric scooters (n = 9) simulated boarding and disembarking in three interior layout configurations at low and high passenger crowding conditions on a full-scale laboratory mock-up of a low-floor bus. Dependent measures comprised task times and critical incidents during access ramp use, fare payment, and movement to and from the doorway and wheeled mobility securement area. Individual times for unassisted boarding ranged from 15.2 to 245.3 s and for disembarking ranged from 9.1 to 164.6 s across layout and passenger crowding conditions. Nonparametric analysis of variance showed significant differences and interactions across vehicle design conditions, passenger load and mobility device type on user performance. The configuration having electronic on-board fare payment, rear-bus entrance doorways and adjacent device securement areas demonstrated greatest efficiency and safety. High passenger load adversely impacted efficiency and frequency of critical incidents during on-board circulation across all three layouts. Findings have broader implications for improving transit system efficiency and quality of service across the spectrum of transit users