4,034 research outputs found
Meiotic sex chromosome cohesion and autosomal synapsis are supported by Esco2.
In mitotic cells, establishment of sister chromatid cohesion requires acetylation of the cohesin subunit SMC3 (acSMC3) by ESCO1 and/or ESCO2. Meiotic cohesin plays additional but poorly understood roles in the formation of chromosome axial elements (AEs) and synaptonemal complexes. Here, we show that levels of ESCO2, acSMC3, and the pro-cohesion factor sororin increase on meiotic chromosomes as homologs synapse. These proteins are less abundant on the largely unsynapsed sex chromosomes, whose sister chromatid cohesion appears weaker throughout the meiotic prophase. Using three distinct conditional Esco2 knockout mouse strains, we demonstrate that ESCO2 is essential for male gametogenesis. Partial depletion of ESCO2 in prophase I spermatocytes delays chromosome synapsis and further weakens cohesion along sex chromosomes, which show extensive separation of AEs into single chromatids. Unsynapsed regions of autosomes are associated with the sex chromatin and also display split AEs. This study provides the first evidence for a specific role of ESCO2 in mammalian meiosis, identifies a particular ESCO2 dependence of sex chromosome cohesion and suggests support of autosomal synapsis by acSMC3-stabilized cohesion
NeatVision: a development environment for machine vision engineers
This Chapter will detail a free image analysis development environment for machine vision engineers. The environment provides high-level access to a wide range of image manipulation, processing and analysis algorithms (over 300 to date) through a well-defined and easy to use graphical interface. Users can extend the core library using the developerâs interface, a plug-in, which features, automatic source code generation, compilation with full error feedback and dynamic algorithm updates. The Chapter will also discuss key issues associated with the environment and outline the advantages in adopting such a system for machine vision application developmen
Real-time colour recognition in symbolic programming for machine vision systems
It is impossible to collect more than a tiny proportion of all of the possible examples of a given hue to form a training set for a machine that learns to discriminate colours. In view of this, it is argued that colour generelization is essential. Three mechanisms for learning colours, as defined by a human being, are described. One of these is based upon an idea developed by A.P. Plummer and is implemented in a commercial device known as the ldquointelligent camerardquo. This implementation can learn the characteristics of coloured scenes presented to it and can segment a video image in real-time. This paper presents four procedures that allow the range of colours learned by such a system to be broadened so that recognition is made more reliable and less prone to generating noisy images that are difficult to analyse. Three of the procedures can be used to improve colour discrimination, while a fourth procedure is used when a single and general colour concept has to be learned. Several experiments were devised to demonstrate the effectiveness of colour generelization. These have shown that it is indeed possible to achieve reliable colour discrimination / recognition for such tasks as inspecting packaging and fruit. A practical system based upon the intelligent camera and controlled by software written in PROLOG has been developed by the authors and is being used in a study of methods for declarative programming of machine vision systems for industrial applications
Adverse Selection and Incentives in an Early Retirement Program
We evaluate potential determinants of enrollment in an early retirement incentive program for non-tenure-track employees at a large university. Using administrative records on the eligible population of employees not covered by collective bargaining agreements, historical employee count and layoff data by budget units, and public information on unit budgets, we find dips in per-employee finances in a budget unit during the application year and higher recent per employee layoffs were associated with increased probabilities of eligible employee program enrollment. Our results also suggest that, on average, employees whose salaries are lower than we would predict given their personal characteristics and job titles were more likely to enroll in the early retirement program. To the extent that employees' compensation reflect their productivity, as it should under a pay system in which annual salary increases are based on merit, this finding suggests that adverse selection was not a problem with the program. That is, we find no evidence that on average the "most productive" employees took the incentive.retirement incentive program, adverse selection, layoff threat, university
Adverse Selection and Incentives in an Early Retirement Program
We evaluate potential determinants of enrollment in an early retirement incentive program for non-tenure-track employees of a large university. Using administrative record on the eligible population of employees not covered by collective bargaining agreements, historical employee count and layoff data by budget units, and public information on unit budgets, we find dips in per-employee finance in a budget unit during the application year and higher recent per employee layoffs were associated with increased probabiliites of eligible employee program enrollment. Our results also suggest, on average, that employees whose salaries are lower than we would predict given their personal characteristics and job titles were more likely to enroll in the early retirement program. To the extent that employees' compensation reflects their productivity, as it should under a pay system in which annual salary increases are based on merit, this finidng suggests that adverse selection was not a problem with the program. That is, we find no evidence that on average the "most productive" employees took the incentive.
Adverse Selection and Incentives in an Early Retirement Program
We evaluate potential determinants of enrollment in an early retirement incentive program for non-tenure-track employees of a large university. Using administrative record on the eligible population of employees not covered by collective bargaining agreements, historical employee count and layoff data by budget units, and public information on unit budgets, we find dips in per-employee finance in a budget unit during the application year and higher recent per employee layoffs were associated with increased probabilities of eligible employee program enrollment. Our results also suggest, on average, that employees whose salaries are lower than we would predict given their personal characteristics and job titles were more likely to enroll in the early retirement program. To the extent that employees\u27 compensation reflects their productivity, as it should under a pay system in which annual salary increases are based on merit, this finding suggests that adverse selection was not a problem with the program. That is, we find no evidence that on average the most productive employees took the incentive
Evolution of Hard X-Ray Spectra Along the Branches in Cir X-1
Using the data from the PCA and HEXTE on board the RXTE satellite, we
investigate the evolution of the 3-200 keV spectra of the peculiar low mass
X-ray binary (LMXB) Cir X-1 along the branches on its hardness-intensity
diagram (HID) from the vertical horizontal branch (VHB), through the horizontal
horizontal branch (HHB) and normal branch (NB), to the flaring branch (FB). We
detect a power-law hard component in the spectra. It is found that the derived
photon indices () of the power-law hard component are correlated with
the position on the HID. The power-law component dominates the X-ray emission
of Cir X-1 in the energy band higher than keV. The fluxes of the
power-law component are compared with those of the bremsstrahlung component in
the spectra. A possible origin of the power-law hard component is discussed.Comment: 14 pages, 5 figures, ApJ Letter accepte
Electron-impact ionization of atomic hydrogen at 2 eV above threshold
The convergent close-coupling method is applied to the calculation of fully
differential cross sections for ionization of atomic hydrogen by 15.6 eV
electrons. We find that even at this low energy the method is able to yield
predictive results with small uncertainty. As a consequence we suspect that the
experimental normalization at this energy is approximately a factor of two too
high.Comment: 10 page
Enhancement of electroporation facilitated immunogene therapy via T-reg depletion
Regulatory T cells (T-regs) can negatively impact tumor antigen-specific immune responses after infiltration into tumor tissue. However, depletion of T-regs can facilitate enhanced anti-tumor responses, thus augmenting the potential for immunotherapies. Here we focus on treating a highly aggressive form of cancer using a murine melanoma model with a poor prognosis. We utilize a combination of T-reg depletion and immunotherapy plasmid DNA delivered into the B16F10 melanoma tumor model via electroporation. Plasmids encoding murine granulocyte macrophage colony-stimulating factor and human B71 were transfected with electroporation into the tumor and transient elimination of T-regs was achieved with CD25-depleting antibodies (PC61). The combinational treatment effectively depleted T-regs compared to the untreated tumor and significantly reduced lung metastases. The combination treatment was not effective in increasing the survival, but only effective in suppression of metastases. These results indicate the potential for combining T-reg depletion with immunotherapy-based gene electrotransfer to decrease systemic metastasis and potentially enhance survival
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