Performance on a repetitive key pressing task as a function of the spatial positioning of the stimulus and response components.

1954 ◽  
Author(s):  
Norman H. Anderson ◽  
David A. Grant ◽  
Charles O. Nystrom
Keyword(s):  
2004 ◽  
Vol 382 (2) ◽  
pp. 463-470 ◽  
Author(s):  
Onard J. L. M. SCHONEVELD ◽  
Ingrid C. GAEMERS ◽  
Atze T. DAS ◽  
Maarten HOOGENKAMP ◽  
Johan RENES ◽  
...  

The GRU (glucocorticoid-response unit) within the distal enhancer of the gene encoding carbamoyl-phosphate synthase, which comprises REs (response elements) for the GR (glucocorticoid receptor) and the liver-enriched transcription factors FoxA (forkhead box A) and C/EBP (CCAAT/enhancer-binding protein), and a binding site for an unknown protein denoted P3, is one of the simplest GRUs described. In this study, we have established that the activity of this GRU depends strongly on the positioning and spacing of its REs. Mutation of the P3 site within the 25 bp FoxA–GR spacer eliminated GRU activity, but the requirement for P3 could be overcome by decreasing the length of this spacer to ≤12 bp, by optimizing the sequence of the REs in the GRU, and by replacing the P3 sequence with a C/EBPβ sequence. With spacers of ≤12 bp, the activity of the GRU depended on the helical orientation of the FoxA and GR REs, with highest activities observed at 2 and 12 bp respectively. Elimination of the 6 bp C/EBP–FoxA spacer also increased GRU activity 2-fold. Together, these results indicate that the spatial positioning of the transcription factors that bind to the GRU determines its activity and that the P3 complex, which binds to the DNA via a 75 kDa protein, functions to facilitate interaction between the FoxA and glucocorticoid response elements when the distance between these transcription factors means that they have difficulties contacting each other.


2021 ◽  
Vol 1748 ◽  
pp. 042011
Author(s):  
Xing Zhang ◽  
Qiaoming Gao ◽  
Dong Pan ◽  
Peng Cheng Cao ◽  
Dong Hui Huang

2007 ◽  
Vol 189 (20) ◽  
pp. 7442-7449 ◽  
Author(s):  
Benjamin M. Hasselbring ◽  
Duncan C. Krause

ABSTRACT Mycoplasma pneumoniae is a major cause of bronchitis and atypical pneumonia in humans. This cell wall-less bacterium has a complex terminal organelle that functions in cytadherence and gliding motility. The gliding mechanism is unknown but is coordinated with terminal-organelle development during cell division. Disruption of M. pneumoniae open reading frame MPN311 results in loss of protein P41 and downstream gene product P24. P41 localizes to the base of the terminal organelle and is required to anchor the terminal organelle to the cell body, but during cell division, MPN311 insertion mutants also fail to properly regulate nascent terminal-organelle development spatially or gliding activity temporally. We measured gliding velocity and frequency and used fluorescent protein fusions and time-lapse imaging to assess the roles of P41 and P24 individually in terminal-organelle development and gliding function. P41 was necessary for normal gliding velocity and proper spatial positioning of new terminal organelles, while P24 was required for gliding frequency and new terminal-organelle formation at wild-type rates. However, P41 was essential for P24 function, and in the absence of P41, P24 exhibited a dynamic localization pattern. Finally, protein P28 requires P41 for stability, but analysis of a P28− mutant established that the MPN311 mutant phenotype was not a function of loss of P28.


2017 ◽  
Vol 8 ◽  
Author(s):  
Charlotte Harrison ◽  
Nicola Binetti ◽  
Isabelle Mareschal ◽  
Alan Johnston

Author(s):  
Peregrine E. J. Riley

Abstract Many manipulators with six degrees of freedom are constructed with two distinct sections, a regional structure for spatial positioning, and an orientational structure having a common intersection point for the joint axes. With this arrangement, inverse kinematic solutions for position and orientation may be found separately. While solutions for general three link manipulators have been available since the work of Pieper in 1969, this paper presents new forms of the inverse kinematic equations for general RRP and RRR regional structures. Cartesian coordinates of the F-surface (generated by movement of the outer two joints) together with the outer joint angle are used as the equation variables. In addition, a second degree polynomial approxiamation of the equation may be used for quick iteration to a solution. It is hoped that these new equations will be useful by themselves and in workspace regions where solutions using equations in terms of the joint variables are numerically inaccurate or impossible.


1994 ◽  
Vol 14 (10) ◽  
pp. 6829-6838
Author(s):  
L Wu ◽  
T Ueda ◽  
J Messing

Two cis-regulatory regions are required for efficient mRNA 3'-end processing of the maize 27-kDa zein mRNA: a region containing a duplicated AAUGAA poly(A) signal and a region that is present upstream from it. Strict spatial positioning of these two regions is required for efficient mRNA 3'-end processing. Insertion of a stuffer sequence as short as 17 or 18 bp either between the upstream region and the two AAUGAA motifs or between the two AAUGAA motifs drastically reduced the efficiency of 3'-end processing. Mutational analyses of the nucleotide preference at the fourth position of the AAUGAA motif revealed the preference order G > A >> C or U, suggesting that AAUAAA is neither a defective nor an optimal poly(A) signal for the 27-kDa zein mRNA. As for the 3' control region of the cauliflower mosaic virus (CaMV) transcription unit, the mRNA 3'-end processing mechanism mediated by the 27-kDa zein 3' control sequence is neither tissue nor species specific. The 3' upstream sequence of the 27-kDa zein gene can functionally replace that of the CaMV transcription unit. Conversely, the CaMV upstream sequence can mediate mRNA polyadenylation in the presence of a duplicated 27-kDa zein poly(A) signal. However, instead of the proximal poly(A) signal normally used in the 27-kDa zein mRNA, the distal signal is utilized. These results suggest that a general mechanism controls the 3'-end processing of plant mRNAs and that the cis-regulatory functions mediated by their upstream regions are interchangeable.


1956 ◽  
Vol 40 (3) ◽  
pp. 137-141 ◽  
Author(s):  
Norman H. Anderson ◽  
David A. Grant ◽  
Charles O. Nystrom
Keyword(s):  

2018 ◽  
Vol 132 (4) ◽  
pp. jcs219550 ◽  
Author(s):  
Daniel Roth ◽  
Benjamin P. Fitton ◽  
Nikola P. Chmel ◽  
Natalia Wasiluk ◽  
Anne Straube

2017 ◽  
Vol 1 (1) ◽  
pp. 1-7 ◽  
Author(s):  
Gilles Clément ◽  
Angie Bukley

The objective of this study was to study the selection of seat location by individuals in a group in a confined environment and to identify the factors leading people to prefer one location to another. We analyzed the seating location of students in a lecture hall over the course of two academic programs of different durations (19 days and 44 days). The goal was to determine the rate at which participants would settle into a specific seat location. Unobtrusive photography was used to collect objective data on an hourly basis. Results showed that in both courses participants began to settle into a specific location from the second day of class. Twenty percent of the participants had settled after 4-7 days or 15.5 hours in class. Settling continued for the duration of the shorter course. However, in the longer course settling stopped after 28.5 days on average. The plateau in the number of settlers depended on the number of days, not on the time actually spent in class. At the end of the longer course 52.5% of the participants had settled, compared to 38.9% in the shorter course. Settling into the same seat location can be interpreted as a strategy to establish a personal territory. These results indicate that about half of a cohort expresses the need for establishing a personal territory when in a confined and crowded environment, and this process takes about one month.


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