Muller's ratchet decreases fitness of a DNA-based microbe.

Muller proposed that an asexual organism will inevitably accumulate deleterious mutations, resulting in an increase of the mutational load and an inexorable, ratchet-like, loss of the least mutated class [Muller, H.J. (1964) Mutat. Res. 1, 2-9]. The operation of Muller's ratchet on real populations has been experimentally demonstrated only in RNA viruses. However, these cases are exceptional in that the mutation rates of the RNA viruses are extremely high. We have examined whether Muller's ratchet operates in Salmonella typhimurium, a DNA-based organism with a more typical genomic mutation rate. Cells were grown asexually under conditions expected to result in high genetic drift, and the increase in mutational load was determined. S. typhimurium accumulated mutations under these conditions such that after 1700 generations, 1% of the 444 lineages tested had suffered an obvious loss of fitness, as determined by decreased growth rate. These results suggest that in the absence of sex and with high genetic drift, genetic mechanisms, such as back or compensatory mutations, cannot compensate for the accumulation of deleterious mutations. In addition, we measured the appearance of auxotrophs, which allowed us to calculate an average spontaneous mutation rate of approximately 0.3-1.5 x 10(-9) mutations per base pair per generation. This rate is measured for the largest genetic target studied so far, a collection of about 200 genes.

A Computational Method based on Radio Frequency Technologies for the Analysis of Accessibility of Disabled People in Sustainable Cities

The sustainability strategy in urban spaces arises from reflecting on how to achieve a more habitable city and is materialized in a series of sustainable transformations aimed at humanizing different environments so that they can be used and enjoyed by everyone without exception and regardless of their ability. Modern communication technologies allow new opportunities to analyze efficiency in the use of urban spaces from several points of view: adequacy of facilities, usability, and social integration capabilities. The research presented in this paper proposes a method to perform an analysis of movement accessibility in sustainable cities based on radio frequency technologies and the ubiquitous computing possibilities of the new Internet of Things paradigm. The proposal can be deployed in both indoor and outdoor environments to check specific locations of a city. Finally, a case study in a controlled context has been simulated to validate the proposal as a pre-deployment step in urban environments.

10Be/9Be-based chronostratigraphy of ODP Hole 181-1121B from the Southwest Pacific Ocean

A 10Be/9Be-based chronostratigraphy has been determined for ODP 181, Site 1121 sediment core, recovered from the foot of the Campbell Plateau, Southwest Pacific Ocean. This core was drilled through the Campbell 'skin drift' in ca. 4500 m water depth on the mid-western margin of the extensive Campbell Nodule Field, beneath the flow of the major cold-water Deep Western Boundary Current (DWBC). In the absence of detailed biostratigraphy, beryllium isotopes have provided essential time information to allow palaeo-environmental interpretation to be undertaken on the upper 7 m of the core. Measured 10Be/9Be ratios of sediment, and of ferromanganese nodules entrapped in the sediment, decrease systematically with depth in the core, in accordance with radioactive decay. However, the 10Be/9Be data diverge from ca. 3 m below the seafloor (mbsf) to the top of the core, giving rise to several possible geochronological models. The preferred model assumes that the measured 10Be/9Be ratios of the nodule rims reflect initial 10Be/9Be ratios equivalent to contemporary seawater, and that these can be used to derive the true age of the sediment where the nodules occur. The nodule rim ages can be then used to interpret the sediment 10Be/9Be data, which indicate an overall age to ca. 7 mbsf of ca. 17.5 Ma. The derived chronology is consistent with diatom biostratigraphy, which indicates an age of 2.2-3.6 Ma at 1 mbsf. Calculated sedimentation rates range from 8 to 95 cm m.y.**-1, with an overall rate to 7 mbsf of ca. 39 cm m.y.**-1. The lowest rates generally coincide with the occurrence of entrapped nodules, and reflect periods of increased bottom current flow causing net sediment loss. Growth rates of individual nodules decrease towards the top of the sediment core, similar to the observed decrease in growth rate from core to rim of seafloor nodules from the Campbell Nodule Field. This may be related to an overall increase in the vigour of the DWBC from ca. 10 Ma to the present.

A summary of industrial accidents in USAEC facilities /

Suppl. 3 (1961) has a revised edition.

Operational accidents & radiation exposures at DOE facilities.

"DOE/EV-0091."

Annual report / prepared by the Illinois Health Facilities Planning Board.

Ceased with 1995?

Approved eligible nonpublic facilities with allowable costs.

Description based on: 1988-89 (List #3); title from caption.

Health facilities directory.

Caption title.

Inventory of health care facilities and need determinations by planning area /

Description based on: 1985; title from cover.

The Illinois state survey and plan for the construction of hospitals and medical facilities (P.L. 725 and P.L. 482) /

Description based on: 16th annual revision (1964)

The long term care constellation : recommendations of the Community-Based Long Term Care Reform Task Force to Governor Jim Edgar.

January 1996.

The Illinois state plans, fiscal year ... for the construction of facilities for the mentally retarded (Title I-C) and community mental health centers (Title II) Public Law 88-164.

Title varies slightly.

Consideration of miscellaneous bills and resolutions : markups before the Committee on Foreign Affairs, House of Representatives, One Hundred Second Congress, second session, on H. Con. Res. 239, H.J. Res. 414, H. Con. Res. 293 ....

"H. Con. Res. 239, H.J. Res. 414, H. Con. Res. 293, H. Con. Res. 292, H. Con. Res. 306, H. Con. Res. 311, H. Con. Res. 305, H. Con. Res. 156, H. Con. Res. 297, H. Con. Res. 299, H. Con. Res. 461, H. Con. Res. 232, H.R. 4761, H.R. 994, H.R. 5412, H. Con. Res. 179, H.R. 5360, S.J. Res. 310, H. Con. Res. 348, H.R. 3215, H.R. 4537, H.R. 4483, H.R. 4059, H. Con. Res. 352, H. Res. 497, H.R. 5751, and H.R. 5360."

Bulletin consulaire français : recueil des rapports commerciaux adressés au Ministre des affaires étrangères par les agents diplomatiques et consulaires de France à l'etranger.

At head of title: 1880-1881: Ministère de l'agriculture et du commerce; 1882-1886/2: Ministère du commerce; 1887/1-1889/1: Ministère du commerce et de l'industrie; 1889/2-1890/2: Ministère du commerce, de l'industrie et des colonies.

Directory of hospitals, nursing care facilities, homes for the aged, mental health facilities /

Description based on: Jan. 1984; title from cover.