An Investigation into the Meaning of Human-Centered Discontinuous Change Strategies to Individuals: Selection and Impact

Organizations today can expect change to be an ongoing part of daily life. Successful change programs require that the human element, in addition to process and technical concerns, be addressed. This qualitative research in progress is investigating employees\u27 perceptions of the utility and the meaning of change management methods used within the organization. The final objective is to tell the story of the change process from the perspective of those involved

Longevity, fertility, sex ratio, and host preference of Diaeretiella Rapae (McIntosh) (Hymenoptera : Aphidiidae)

Suitability of the green peach aphid, Myzus persicae (Sulzer), and the cabbage aphid, Brevicoryne brassicae (L.), as hosts for the parasite Diaeretiella rapae (Mclntosh) was determined by comparing longevity and fertility of the adult female prasite and the sex ratio of the progeny on each of the host species. Preference was determined and its impact assessed. Both aphid species were found to be suitable hosts with no significant differences in developmental or performance criteria. When given a choice, D. rapae oviposited more frequently in the cabbage aphid and a significantly greater percentage of female progeny was produced with that host

Malathion for the Control of Pests of Ornamentals in Southern Arizona: A Progress Report

This item is part of the Agricultural Experiment Station archive. It was digitized from a physical copy provided by the University Libraries at the University of Arizona. For more information, please email CALS Publications at [email protected]

A Study of The Effect of An Equal Energy Spectrum Upon Metallic Selenium In Vacuo

Since little has been found in the literature, on the effect of a actinic properties on the conductivity of metallic selenium and on its spectral response when possessing these properties, it was thought noteworthy to construct several selenium cells having low and medium dark resistances and to study them with a view of seeking some correlation between their conductivity characteristics and their prismatic response in vacuo

The life history of Cyclocoelum Microcotyleum

Monostome trematodes of the family cyclocoelidae, taken from the American coot, Fulica americana, were described as a new species, Cyclocoelum microcotyleum, by Noble in 1933. These flukes were found in the air-spaces or the coelomes of birds taken from the waterways near Stockton, California. Before this present work various attempts had been made to determine the lite history of this fluke. A number of fresh-water snails, indigenous to the region in which the definitive host was found, were exposed to miracidia of this fluke, but observations or infection were not obtained. In the winter of 1940-41 specimens of the fresh-water snail Physa sp. were exposed to the newly-hatched miracidia of this fluke, and various stages of the larval forms were observed

Measurements of broad sense heritability of generation time and motility in cancer cell lines

Experiments were conducted over 7 months to record the motility and generation time of four cancer cell lines - HeLa, HT1080, MCF7 and MDA-MB-231 - in cell culture. Cell lines were cultured in vitro on a well plate for 24 hours before being placed into the environmental chamber of a Nikon TiE Timelapse Microscope. Multiple points within every well were chosen and videoed over a period of 72 hours. These videos were then analysed and cell motility and division tracked using MtrackJ and ImageJ. Records were kept of which cells divided and the track number assigned to each daughter cell. This allowed comparison between and within cell families so the heritability of the cell traits, motility and generation time, could be estimated. Broad sense heritability was estimated as the slope parameter of an ordinary least squares regression between related cells. Three cell-cell relationships were tested, mother-daughter, sister-sister and cousin-cousin. Our results showed that cell motility has high and significant heritability for all cell lines tested whereas generation time showed little or no significant heritability for the cell lines tested. This is consistent with expectations that traits closely linked to fitness will in general have lower heritability. These results are important for cancer evolution as heritability (a prerequisite for natural selection to be able to act) has never before been measured for any traits in cancer cells

Cancer cell lines show high heritability for motility but not generation time

Tumour evolution depends on heritable differences between cells in traits affecting cell survival or replication. It is well established that cancer cells are genetically and phenotypically heterogeneous; however, the extent to which this phenotypic variation is heritable is far less well explored. Here, we estimate the broad-sense heritability (H2) of two cell traits related to cancer hallmarks––cell motility and generation time––within populations of four cancer cell lines in vitro and find that motility is strongly heritable. This heritability is stable across multiple cell generations, with heritability values at the high end of those measured for a range of traits in natural populations of animals or plants. These findings confirm a central assumption of cancer evolution, provide a first quantification of the evolvability of key traits in cancer cells and indicate that there is ample raw material for experimental evolution in cancer cell lines. Generation time, a trait directly affecting cell fitness, shows substantially lower values of heritability than cell speed, consistent with its having been under directional selection removing heritable variation