Atmospheric Neutrinos and the Oscillations Bonanza

New observations with atmospheric neutrinos from the underground experiments SuperKamiokande, Soudan 2, and MACRO, together with earlier results from Kamiokande and IMB, are reviewed. The most recent observations reconfirm aspects of atmospheric flavor content and of zenith angle distributions which appear anomalous in the context of null oscillations. The anomalous trends, exhibited with high statistics in both sub-GeV and multi-GeV data of the SuperKamiokande water Cherenkov experiment, occur also in event samples recorded by the tracking calorimeters. The data are well-described by disappearence of nu_mu flavor neutrinos arising in oscillations with dominant two-state mixing, for which there exists a parameter region allowed by all experiments. In a new analysis by SuperKamiokande, nu_mu -> nu_tau is favored over nu_mu -> nu_s as the dominant oscillation based upon absence of oscillation suppression from matter effects at high energies. The possibility for sub-dominant nu_mu -> nu_e oscillations in atmospheric neutrinos which arises with three-flavor mixing, is reviewed, and intriguing possibilities for amplification of this oscillation by terrestrial matter-induced resonances are discussed. Developments and future measurements which will enhance our knowledge of the atmospheric neutrino fluxes are briefly noted.Comment: Plenary talk at the XIX Int. Symposium on Lepton and Photon Interactions at High Energies, Stanford, Aug. 1999, 28 pages, 16 figures; added a reference for section 1

Rotary target V-block

A device used in the optical alignment of machinery to maintain a measuring scale in the proper position for optical readings to be taken is described. The device consists of a block containing a notch in the shape of an inverted ""v'' and a rotatable plug positioned over the centerline of notch. The block is placed on the object to be aligned, the notch allows the block to be securely placed upon flat or curved surfaces. A weighted measuring scale is inserted through plug so that it contacts the object to be aligned. The scale and plug combination can be rotated so that the scale faces an optical aligning instrument. The instrument is then used in conjunction with the scale to measure the distance of the machinery from a reference plane

M Dwarf Metallicities and Giant Planet Occurrence: Ironing Out Uncertainties and Systematics

Comparisons between the planet populations around solar-type stars and those orbiting M dwarfs shed light on the possible dependence of planet formation and evolution on stellar mass. However, such analyses must control for other factors, i.e. metallicity, a stellar parameter which strongly influences the occurrence of gas giant planets. We obtained infrared spectra of 121 M dwarfs stars monitored by the California Planet Search (CPS) and determined metallicities with an accuracy of 0.08 dex. The mean and standard deviation of the sample is -0.05 and 0.20 dex, respectively. We parameterized the metallicity dependence of the occurrence of giant planets on orbits with period less than 2 yr around solar-type stars and applied this to our M dwarf sample to estimate the expected number of giant planets. The number of detected planets (3) is lower than the predicted number (6.4) but the difference is not very significant (12% probability of finding as many or fewer planets). The three M dwarf planet hosts are not especially metal rich and the most likely value of the power-law index relating planet occurrence to metallicity is 1.06 dex per dex for M dwarfs compared to 1.80 for solar-type stars; this difference, however, is comparable to uncertainties. Giant planet occurrence around both types of stars allows, but does not necessarily require, mass dependence of $\sim 1$ dex per dex. The actual planet-mass-metallicity relation may be complex and elucidating it will require larger surveys like those to be conducted by ground-based infrared spectrographs and the Gaia space astrometry mission.Comment: Accepted to The Astrophysical Journa

X-ray/optical classification of cluster mergers and the evolution of the cluster merger fraction

We present the results of a simple but robust morphological classification of a statis- tically complete sample of 108 of the most X-ray luminous clusters at 0.15 < z < 0.7 observed with Chandra. Our aims are to (a) identify the most disturbed massive clusters to be used as gravitational lenses for studies of the distant universe and as probes of particle acceleration mechanisms resulting in non-thermal radio emission, (b) find cluster mergers featuring subcluster trajectories that make them suitable for quantitative analyses of cluster collisions, and (c) constrain the evolution with redshift of the cluster merger fraction. Finally, (d) this paper represents the third public release of clusters from the MACS sample, adding 24 clusters to the 46 published previously. To classify clusters by degree of relaxation, we use the projected offset of the brightest cluster galaxy from the peak (or the global centroid) of the X-ray emission as a measure of the segregation between the intracluster gas and dark matter. Regarding (a), we identify ten complex systems likely to have undergone multiple merger events in the recent past. Regarding (b), we identify eleven systems likely to be post-collision, binary, head-on mergers (BHOMs), as well as another six mergers that are possible BHOMs but probably harder to interpret because of non-negligible impact parameters and merger axes closer to our line of sight. Regarding (c), we find a highly significant increase with redshift in the fraction of morphologically disturbed clusters starting at z \sim 0.4, in spite of a detection bias in our sample against very disturbed systems at high redshift. A larger sample of clusters with high-quality X-ray data in particular at high redshift will be needed to trace the evolutionary history of cluster growth and relaxation closer to the primary epoch of cluster formation z \sim 1.Comment: Accepted to MNRA

Compact artificial hand

A relatively simple, compact artificial hand, is described which includes hooks pivotally mounted on first frame to move together and apart. The first frame is rotatably mounted on a second frame to enable "turning at the wrist" movement without limitation. The second frame is pivotally mounted on a third frame to permit 'flexing at the wrist' movement. A hook-driving motor is fixed to the second frame but has a shaft that drives a speed reducer on the first frame which, in turn, drives the hooks. A second motor mounted on the second frame, turns a gear on the first frame to rotate the first frame and the hooks thereon. A third motor mounted on the third frame, turns a gear on a second frame to pivot it

Formation of Topological Black holes from Gravitational Collapse

We consider the gravitational collapse of a dust cloud in an asymptotically anti de Sitter spacetime in which points connected by a discrete subgroup of an isometry subgroup of anti de Sitter spacetime are identified. We find that black holes with event horizons of any topology can form from the collapse of such a cloud. The quasilocal mass parameter of such black holes is proportional to the initial density, which can be arbitrarily small.Comment: latex, 16 pages, four postscript figure