18 research outputs found
How similar are the different results?
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/43555/1/11135_2004_Article_BF00145805.pd
Equity In A Brokerage Firm.
PhDSociologyUniversity of Michigan, Horace H. Rackham School of Graduate Studieshttp://deepblue.lib.umich.edu/bitstream/2027.42/190562/2/7415793.pd
ACTIVITY CONTROLLER FOR A MULTIPLE ROBOT ASSEMBLY CELL
The research addresses the problems of the Activity Controller for a Multiple Robot Assembly Cell. It includes analysis and development of planning and control algorithms for operation of multi-robot assembly systems. The problem defined for the Activity Controller is which robot is to perform which operations; how, in terms of spatial routes and accessories; and when, in terms of timing and synchronization, in order to effectively achieve certain task objectives (e.g., minimize makespan time). General algorithms for the Activity Controller are presented emphasizing the real time operational control. Experimental work serves as a concept proof by designing and implementing the control algorithms on a computer controlled system. The system was used to simultaneously operate two robots that share tasks and auxiliary devices. The research is concluded with a scheme for evaluating the potential advantages of multi-robot assembly cell under an Activity Controller
Performance and Autonomy in Organizations: Determining Dominant Environmental Components
The formulation of a strategy for an organization begins with identifying the opportunities and risks in the environment. A full and permanent search--or scanning--of all environmental forces is both too costly and intractable in terms of management time. Our findings indicate that managers do not try to identify all environmental forces. Identifying the dominant components of the environment focuses scanning efforts and saves energy and costs. Furthermore, our findings clearly point out that achievement of autonomy may be advanced by organizational performance. An optimal strategy for a manager seeking to increase autonomy would be to concentrate efforts on dominant environmental components. A spillover effect will generalize this autonomy.
Evidence for Gene Flow between Two Sympatric Mealybug Species (Insecta; Coccoidea; Pseudococcidae)
<div><p>Occurrence of inter-species hybrids in natural populations might be evidence of gene flow between species. In the present study we found evidence of gene flow between two sympatric, genetically related scale insect species – the citrus mealybug <i>Planococcus citri</i> (Risso) and the vine mealybug <i>Planococcus ficus</i> (Signoret). These species can be distinguished by morphological, behavioral, and molecular traits. We employed the sex pheromones of the two respective species to study their different patterns of male attraction. We also used nuclear ITS2 (internal transcribed spacer 2) and mitochondrial COI (Cytochrome c oxidase sub unit 1) DNA sequences to characterize populations of the two species, in order to demonstrate the outcome of a possible gene flow between feral populations of the two species. Our results showed attraction to <i>P. ficus</i> pheromones of all tested populations of <i>P. citri</i> males but not vice versa. Furthermore, ITS2 sequences revealed the presence of ‘hybrid females’ among <i>P. citri</i> populations but not among those of <i>P. ficus</i>. ‘hybrid females’ from <i>P. citri</i> populations identified as <i>P. citri</i> females according to COI sequences. We offer two hypotheses for these results. 1) The occurrence of phenotypic and genotypic traits of <i>P. ficus</i> in <i>P. citri</i> populations may be attributed to both ancient and contemporary gene flow between their populations; and 2) we cannot rule out that an ancient sympatric speciation by which <i>P. ficus</i> emerged from <i>P. citri</i> might have led to the present situation of shared traits between these species. In light of these findings we also discuss the origin of the studied species and the importance of the pherotype phenomenon as a tool with which to study genetic relationships between congener scale insects.</p></div
ITS2 sequences amplified from three types of females.
<p>A- Individuals with more than 98% identity with <i>P. citri</i> GenBank references, considered as <i>P. citri</i>. B- Individuals with more than 98% identity with <i>P. ficus</i> GenBank references, considered as <i>P. ficus</i>. H- Individuals with less than 92% identity with <i>P. citri</i> and <i>P. ficus</i> GenBank references, confirmed as hybrids of the two species by cloning sequencing. Black arrows mark double-peak signals indicating the existence of heterozygosity in this region. ITS2 GenBank references: <i>P. ficus</i>: GU134677, JQ085574, HQ852471; <i>P. citri</i>: JF714195. COI GenBank references: <i>P. ficus</i>: JN120845, EU250573, DQ238220; <i>P. citri</i>: AB439517, AF483204.</p
ITS2 sequencing identity according to GenBank references of females from various locations.
<p>The females were divided in to three groups: A- Individuals with more than 98% identity with <i>P. citri</i>, considered as <i>P. citri</i>. B- Individuals with more than 98% identity with <i>P. ficus</i>, considered as <i>P. ficus</i>. H- Individuals with less than 92% identity with <i>P. citri</i> and <i>P. ficus</i>, confirmed after cloning and sequencing as hybrids of the two species (CM refers to <i>P. citri</i> and VM to <i>P. ficus</i>). ITS2 GenBank references: <i>P. ficus</i>: GU134677, JQ085574, HQ852471, <i>P. citri</i>: JF714195. The species of the populations determined by COI sequencing and comparison to GenBank references (<i>P. ficus</i>: JN120845, EU250573, DQ238220 and <i>P. citri</i>: AB439517, AF483204).</p>*<p>Numbering according to <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0088433#pone-0088433-t002" target="_blank">Table 2</a>.</p>**<p>Number of examined specimens.</p>***<p>Cloning could not obtained.</p
List of the studied populations with respect to their origins and host plants.
*<p>Commercial greenhouse.</p