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Aims. The aim of this paper is twofold: $(a)$to determine the reliability of infrared (IR) emission to trace star formation in individual star-forming sites of M 33, and $(b)$to outline a new method for testing the distribution function of massive stars in newly formed clusters.

We investigate the properties of a clump-cluster galaxy at redshift 1.57. In optical observations, the morphology of this galaxy is dominated by eight star-forming clumps, and its photometric properties are typical of most clump-cluster and chain galaxies. Its complex asymmetrical morphology has led to the suggestion that this system is a group merger of several initially separate proto-galaxies. We performed Hαintegral field spectroscopy of this system using SINFONI on VLT UT4. These observations reveal a large-scale velocity gradient throughout the system, but with large local kinematic disturbances. Using a numerical model of gas-rich disk fragmentation, we find that clump interactions and migration can explain the observed disturbed rotation. On the other hand, the global rotation would not be expected for a multiply merging system. We also find that this system follows the relations of stellar mass versus metallicity, star formation rate, and size that are expected for a disk at this redshift. Furthermore, the galaxy exhibits a disk-like radial metallicity gradient. A formation scenario of internal disk fragmentation is therefore the most likely one. A red and metallic central concentration appears to be a bulge in this proto-spiral clumpy galaxy. A chain galaxy at redshift 2.07 in the same field also shows disk-like rotation. Such systems are likely progenitors of present-day bright spiral galaxies, which shape their exponential disks through clump migration and disruption, a process that in turn fuels their bulges. Our results show that disturbed morphologies and kinematics are not necessarily signs of galaxy mergers and interactions, but may instead be produced by the internal evolution of primordial disks.

We describe the results of a long-slit spectroscopic study of an unusual star complex in the nearby spiral galaxy NGC 6946 using the SAO 6 m telescope and the Keck 10 m telescope. The complex resembles a circular bubble 600 pc in diameter with a young super star cluster (SSC) near the center. The kinematics of ionized gas is studied through Hαemission with several slit positions. Position–velocity diagrams show two distinct features with high speed motions. One is an irregularly shaped region to the east of the SSC, 270 pc in size, in which most of the Hαemission is blue shifted by 120 km s-1, and another is a 350 pc shell centered on the SSC with positive and negative velocity shifts of 60 km s-1. Balmer and $\ion{He}{i}$absorption lines in the SSC give an age of 12–13 Myr, which is consistent with the photometric age but significantly older than the kinematic ages of the high speed regions. The energetics of the SSC and its interaction with the environment are considered. The expansion energies exceed 1052ergs, but the power outputs from winds and supernova in the SSC are large enough to account for this. The intensities of Balmer, [$\ion{N}{ii}$], and [$\ion{S}{ii}$] emission lines within and around the complex indicate that shock excitation makes a significant contribution to the emission from the most energetic region.

The relative bar torques for 45 galaxies observed at K-band with the 4.2 m William Herschel Telescope are determined by transforming the light distributions into potentials and deriving the maximum ratios of the tangential forces relative to the radial forces. The results are combined with the bar torques for 30 other galaxies determined from our previous K-band survey (Buta & Block [CITE]). Relative bar torques determine the degree of spiral arm forcing, gas accretion, and bar evolution. They differ from other measures of bar strength, such as the relative amplitude of the bar determined photometrically, because they include the bulge and other disk light that contributes to the radial component of the total force. If the bulge is strong and the radial forcing large, then even a prominent bar can have a relatively weak influence on the azimuthal motions in the disk. Here we find that the relative bar torque correlates only weakly with the optical bar type listed in the Revised Shapley-Ames and de Vaucouleurs systems. In fact, some classically barred galaxies have weaker relative bar torques than classically unbarred galaxies. The optical class is a poor measure of azimuthal disk forcing for two reasons: some infrared bars are not seen optically, and some bars with strong bulges have their azimuthal forces so strongly diluted by the average radial force that they exert only small torques on their disks. The Hubble classification scheme poorly recognizes the gravitational influence of bars. Applications of our bar torque method to the high-redshift universe are briefly discussed.

Moore’s law of transistor scaling, the exponential increase in the number of complementary metal oxide semiconductor (CMOS) transistors per unit area, continues unabated; however, computer clock speeds have remained frozen since 2003. The development of a new digital switch, the piezoelectronic transistor (PET), is designed to circumvent the speed and power limitations of the CMOS transistor. The PET operates on a novel principle: an electrical input is transduced into an acoustic pulse by a piezoelectric element which, in turn, is used to drive a continuous insulator-to-metal transition in a piezoresistive element, thus switching on the device. Performance is enabled by the use of key high response materials, a relaxor piezoelectric, and a rare-earth chalcogenide piezoresistor. Theory and simulation predict, using bulk material properties, that PETs can operate at one-tenth the present voltage of CMOS technology and consuming 100 times less power while running at multi-GHz clock speeds. A program to fabricate prototype PET devices is under way.

Aims. The aim of this paper is twofold: (a) to determine the reliability of infrared (IR) emission to trace star formation in individual star-forming sites of M?33, and (b) to outline a new method for testing the distribution function of massive stars in newly formed clusters. Methods. We select 24??m?IR?sources from the Spitzer?survey of M?33 with H??counterparts and show that the IR? luminosities have a weak dependence on galactocentric radius. The IR?and H??luminosities are not correlated. Complementing the infrared photometry with GALEX-UV?data, we estimate the bolometric luminosities to investigate how they are related to the H??luminosities. We simulate a theoretical diagram for the expected bolometric-to-H? luminosity ratio, Lbol/LH?, of young clusters as a function of the cluster luminosity. We then compare the observed Lbol/LH?ratios with the theoretical predictions. Results. In the log(Lbol)-log(Lbol/LH?) plane, stellar clusters should be born along a curve that we call the cluster birthline. The birthline depends on the stellar initial mass function (IMF) at the high-mass end, but not on the cluster mass function. For an upper stellar mass limit of 120M?, the birthline is flat for Lbol>3?1039?erg?s-1because all clusters fully sample the IMF. It increases toward lower luminosities as the upper end of the IMF becomes incompletely sampled. Aging moves clusters above the birthline. The observations of M?33 show that young isolated clusters lie close to the theoretical birthline for a wide range of Lbol. The observed Lbol/LH?ratio increases toward low Lbollike the theoretical curve, indicating that luminosity is not proportional to H??emission for low mass clusters. The best fit to the birthline is for a randomly sampled IMF, in which the mass of most massive star in a cluster is not strictly limited by the cluster's mass, but can have any value up to the maximum stellar mass with a probability determined by the IMF. We also find that the IR?luminosity of young stellar clusters in M?33 is not proportional to their bolometric luminosity. This irregularity could be the result of low and patchy dust abundance. In M?33 dust absorbs and re-radiates in the IR?only part of the UV?light from young clusters.

Current switching speeds in CMOS technology have saturated since 2003 due to power constraints arising from the inability of line voltage to be further lowered in CMOS below about 1V. We are developing a novel switching technology based on piezoelectrically transducing the input or gate voltage into an acoustic wave which compresses a piezoresistive (PR) material forming the device channel. Under pressure the PR undergoes an insulator-to-metal transition which makes the channel conducting, turning on the device. A piezoelectric (PE) transducer material with a high piezoelectric coefficient, e.g. a domain-engineered relaxor piezoelectric, is needed to achieve low voltage operation. Suitable channel materials manifesting a pressure-induced metal-insulator transition can be found amongst rare earth chalcogenides, transition metal oxides, etc.. Mechanical requirements include a high PE/PR area ratio to step up pressure, a rigid surround material to constrain the PE and PR external boundaries normal to the strain axis, and a void space to enable free motion of the component side walls. Using static mechanical modeling and dynamic electroacoustic simulations, we optimize device structure and materials and predict performance. The device, termed a PiezoElectronic Transistor (PET) can be used to build complete logic circuits including inverters, flip-flops, and gates. This "Piezotronic" logic is predicted to have a combination of low power and high speed operation.