The Caenorhabditis elegans Synthetic Multivulva Genes Prevent Ras Pathway Activation by Tightly Repressing Global Ectopic Expression of lin-3 EGF

The Caenorhabditis elegans class A and B synthetic multivulva (synMuv) genes redundantly antagonize an EGF/Ras pathway to prevent ectopic vulval induction. We identify a class A synMuv mutation in the promoter of the lin-3 EGF gene, establishing that lin-3 is the key biological target of the class A synMuv genes in vulval development and that the repressive activities of the class A and B synMuv pathways are integrated at the level of lin-3 expression. Using FISH with single mRNA molecule resolution, we find that lin-3 EGF expression is tightly restricted to only a few tissues in wild-type animals, including the germline. In synMuv double mutants, lin-3 EGF is ectopically expressed at low levels throughout the animal. Our findings reveal that the widespread ectopic expression of a growth factor mRNA at concentrations much lower than that in the normal domain of expression can abnormally activate the Ras pathway and alter cell fates. These results suggest hypotheses for the mechanistic basis of the functional redundancy between the tumor-suppressor-like class A and B synMuv genes: the class A synMuv genes either directly or indirectly specifically repress ectopic lin-3 expression; while the class B synMuv genes might function similarly, but alternatively might act to repress lin-3 as a consequence of their role in preventing cells from adopting a germline-like fate. Analogous genes in mammals might function as tumor suppressors by preventing broad ectopic expression of EGF-like ligands.National Institutes of Health (U.S.) (grant GM24663)National Institutes of Health (U.S.). Pioneer Award (1DP1OD003936

The LIN-15A and LIN-56 Transcriptional Regulators Interact to Negatively Regulate EGF/Ras Signaling in Caenorhabditis elegans Vulval Cell-Fate Determination

The restricted expression of epidermal growth factor (EGF) family ligands is important for proper development and for preventing cancerous growth in mammals. In Caenorhabditis elegans, the class A and B synthetic multivulva (synMuv) genes redundantly repress expression of lin-3 EGF to negatively regulate Ras-mediated vulval development. The class B synMuv genes encode proteins homologous to components of the NuRD and Myb-MuvB/dREAM transcriptional repressor complexes, indicating that they likely silence lin-3 EGF through chromatin remodeling. The two class A synMuv genes cloned thus far, lin-8 and lin-15A, both encode novel proteins. The LIN-8 protein is nuclear. We have characterized the class A synMuv gene lin-56 and found it to encode a novel protein that shares a THAP-like C_2CH motif with LIN-15A. Both the LIN-56 and LIN-15A proteins localize to nuclei. Wild-type levels of LIN-56 require LIN-15A, and wild-type levels and/or localization of LIN-15A requires LIN-56. Furthermore, LIN-56 and LIN-15A interact in the yeast two-hybrid system. We propose that LIN-56 and LIN-15A associate in a nuclear complex that inhibits vulval specification by repressing lin-3 EGF expression

Origin and possible birthplace of the extreme runaway star HIP 60350

Using the recently determined spatial velocity components of the extreme runaway star HIP 60350 and a gravitation potential model of the Galaxy, we integrate the orbit of HIP 60350 back to the plane of the Galaxy. In this way, a possible location of the formation of the star is determined. We estimate the uncertainty of the result due to the uncertainties of the gravitational potential model and the errors in the spatial velocity components. The place of birth lies (within the errors) near the position of the open cluster NGC 3603. However, the ejection event which occured about 20 Myr ago is in contradiction with the cluster mean age of 3-4 Myr. We suggest that it occured at an earlier phase in sequential star formation in that region. We discuss also ejection mechanisms. Due to the rather high mass of the star (about 5 \Msol), the most probable model is that of dynamical ejection.Comment: Astron. Astrophys. submitted, 7 pages, 5 eps figure

The Influence of Social Evaluation on Heart Rate Variability and Motor Performance: A Study of “Real-Life” Competition

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The auto assist bar system for disabled people

This paper presents the development of the auto assist bar system to help the disabled people especially paralyzed in the legs where they have a problem to doing transaction stand-to-sit and sit-to-stand. An example the difficult movement of people with disabilities are from wheelchair to bed or from wheelchair to the toilet bowl. Many people with disabilities use the grab bars or assist bar are sold in the markets where it is too difficult and require a lot of energy to use which can cause them to fall and injured. Through this system, the disabled people can do the transaction stand-to-sit and sit-to-stand without assistance from other persons. The work will be performed during this project is testing performance of the sensors, design for the entire system either on mechanical parts and use the PID controller by using Arduino to control of dc motor. PID parameter values of Kp, Ki and Kd is obtained which is suitable to enable a dc motor rotates smoothly. The overall results obtained from this project found all managed to achieve the overall objectives of the system where the system is able to support people with disabilities to stand up and sit down

EMG/ENG services rendered by clinical neurophysiology technologists in solo practice

CITATION: Bill, P. L. A., et al. 1998. EMG/ENG services rendered by clinical neurophysiology technologists in solo practice. South African Medical Journal, 88(11):1360.The original publication is available at http://www.samj.org.za[No abstract available]Publisher’s versio

First Kepler results on compact pulsators II: KIC 010139564, a new pulsating subdwarf B (V361 Hya) star with an additional low-frequency mode

We present the discovery of nonradial pulsations in a hot subdwarf B star based on 30.5 days of nearly continuous time-series photometry using the \emph{Kepler} spacecraft. KIC 010139564 is found to be a short-period pulsator of the V361 Hya (EC 14026) class with more than 10 independent pulsation modes whose periods range from 130 to 190 seconds. It also shows one periodicity at a period of 3165 seconds. If this periodicity is a high order g-mode, then this star may be the hottest member of the hybrid DW Lyn stars. In addition to the resolved pulsation frequencies, additional periodic variations in the light curve suggest that a significant number of additional pulsation frequencies may be present. The long duration of the run, the extremely high duty cycle, and the well-behaved noise properties allow us to explore the stability of the periodic variations, and to place strong constraints on how many of them are independent stellar oscillation modes. We find that most of the identified periodicities are indeed stable in phase and amplitude, suggesting a rotation period of 2-3 weeks for this star, but further observations are needed to confirm this suspicion.Comment: 10 pages, accepted for publication in MNRA

Double white dwarf mergers and elemental surface abundances in extreme helium and R Coronae Borealis stars

The surface abundances of extreme helium (EHe) and R Coronae Borealis (RCB) stars are discussed in terms of the merger of a carbon-oxygen white dwarf with a helium white dwarf. The model is expressed as a linear mixture of the individual layers of both constituent white dwarfs, taking account of the specific evolution of each star. In developing this recipe from previous versions, particular attention has been given to the inter-shell abundances of the asymptotic giant branch star which evolved to become the carbon-oxygen white dwarf. Thus the surface composition of the merged star is estimated as a function of the initial mass and metallicity of its progenitor. The question of whether additional nucleosynthesis occurs during the white dwarf merger has been examined. The high observed abundances of carbon and oxygen must either originate by dredge-up from the core of the carbon-oxygen white dwarf during a cold merger or be generated directly by alpha-burning during a hot merger. The presence of large quantities of O18 may be consistent with both scenarios, since a significant O18 pocket develops at the carbon/helium boundary in a number of our post-AGB models. The production of fluorine, neon and phosphorus in the AGB intershell produces n overabundance at the surface of the merged stars, but generally not in sufficient quantity. However, the evidence for an AGB origin for these elements points to progenitor stars with initial masses in the range 1.9 - 3 solar masses. There is not yet sufficient information to discriminate the origin (fossil or prompt) of all the abundance anomalies observed in EHe and RCB stars. Further work is required on argon and s-process elements in the AGB intershell, and on the predicted yields of all elements from a hot merger.Comment: 20 pages, 8 figures, 3 tables, MNRAS in pres

Modeling the System Parameters of 2M1533+3759: A New Longer-Period Low-Mass Eclipsing sdB+dM Binary

We present new photometric and spectroscopic observations for 2M 1533+3759 (= NSVS 07826147). It has an orbital period of 0.16177042 day, significantly longer than the 2.3--3.0 hour periods of the other known eclipsing sdB+dM systems. Spectroscopic analysis of the hot primary yields Teff = 29230 +/- 125 K, log g = 5.58 +/- 0.03 and log N(He)/N(H) = -2.37 +/- 0.05. The sdB velocity amplitude is K1 = 71.1 +/- 1.0 km/s. The only detectable light contribution from the secondary is due to the surprisingly strong reflection effect. Light curve modeling produced several solutions corresponding to different values of the system mass ratio, q(M2/M1), but only one is consistent with a core helium burning star, q=0.301. The orbital inclination is 86.6 degree. The sdB primary mass is M1 = 0.376 +/- 0.055 Msun and its radius is R1 = 0.166 +/- 0.007 Rsun. 2M1533+3759 joins PG0911+456 (and possibly also HS2333+3927) in having an unusually low mass for an sdB star. SdB stars with masses significantly lower than the canonical value of 0.48 Msun, down to as low as 0.30 Msun, were theoretically predicted by Han et al. (2002, 2003), but observational evidence has only recently begun to confirm the existence of such stars. The existence of core helium burning stars with masses lower than 0.40--0.43 Msun implies that at least some sdB progenitors have initial main sequence masses of 1.8--2.0 Msun or more, i.e. they are at least main sequence A stars. The secondary is a main sequence M5 star.Comment: 47 pages, 7 figure

High resolution spectroscopy of bright subdwarf B stars - I. Radial velocity variables

Radial velocity curves for 15 bright subdwarf B binary systems have been measured using high precision radial velocity measurements from high S/N optical high-resolution spectra. In addition, two bright sdB stars are discovered to be radial velocity variable but the period could not yet be determined. The companions for all systems are unseen. The periods range from about 0.18 days up to more than ten days. The radial velocity semi amplitudes are found to lie between 15 and 130 km/s. Using the mass functions, the masses of the unseen companions have been constrained to lower limits of 0.03 up to 0.55 M_sun, and most probable values of 0.03 up to 0.81 M_sun. The invisible companions for three of our program stars are undoubtedly white dwarfs. In the other cases they could be either white dwarfs or main sequence stars. For two stars the secondaries could possibly be brown dwarfs. As expected, the orbits are circular for most of the systems. However, for one third of the program stars we find slightly eccentric orbits with small eccentricities of e~0.02-0.06. This is the first time that non-circular orbits have been found in sdB binaries. No correlation with the orbital period can be found.Comment: Accepted for publication in A&A, 10 pages, 5 figures, quality of Fig.2 is downgraded to fit in the astroph requirement