361 research outputs found
Levi-Civita cylinders with fractional angular deficit
The angular deficit factor in the Levi-Civita vacuum metric has been
parametrized using a Riemann-Liouville fractional integral. This introduces a
new parameter into the general relativistic cylinder description, the
fractional index {\alpha}. When the fractional index is continued into the
negative {\alpha} region, new behavior is found in the Gott-Hiscock cylinder
and in an Israel shell.Comment: 5 figure
Tactile Gloves for Autonomous Grasping With the NASA/DARPA Robonaut
Tactile data from rugged gloves are providing the foundation for developing autonomous grasping skills for the NASA/DARPA Robonaut, a dexterous humanoid robot. These custom gloves compliment the human like dexterity available in the Robonaut hands. Multiple versions of the gloves are discussed, showing a progression in using advanced materials and construction techniques to enhance sensitivity and overall sensor coverage. The force data provided by the gloves can be used to improve dexterous, tool and power grasping primitives. Experiments with the latest gloves focus on the use of tools, specifically a power drill used to approximate an astronaut's torque tool
Quantum tomography, phase space observables, and generalized Markov kernels
We construct a generalized Markov kernel which transforms the observable
associated with the homodyne tomography into a covariant phase space observable
with a regular kernel state. Illustrative examples are given in the cases of a
'Schrodinger cat' kernel state and the Cahill-Glauber s-parametrized
distributions. Also we consider an example of a kernel state when the
generalized Markov kernel cannot be constructed.Comment: 20 pages, 3 figure
"Antiscepticism and Easy Justification" - Ch 5 of Seemings and Epistemic Justification
In this chapter I investigate epistemological consequences of the fact that seeming-based justification is elusive, in the sense that the subject can lose this justification simply by reflecting on her seemings. I argue that since seeming-based justification is elusive, the antisceptical bite of phenomenal conservatism is importantly limited. I also contend that since seeming-based justification has this feature, phenomenal conservatism isn’t actually afflicted by easy justification problems
The Holocene fluvial sedimentary record and alluvial geoarchaeology in the Nile Valley of northern Sudan
True mass flow meter 50. Ein direkt anzeigendes Massenstrom-Messgeraet hoher Genauigkeit fuer transiente Zweiphasenstroemungen bis dm/dt=50 kg/s
Fluessigkeitsdaempfung der Statorschwingungen am True Mass Flow Meter 50, einem Massenstrom-Messgeraet fuer instationaere Zweiphasenstroemungen
Central factorials under the Kontorovich-Lebedev transform of polynomials
We show that slight modifications of the Kontorovich-Lebedev transform lead
to an automorphism of the vector space of polynomials. This circumstance along
with the Mellin transformation property of the modified Bessel functions
perform the passage of monomials to central factorial polynomials. A special
attention is driven to the polynomial sequences whose KL-transform is the
canonical sequence, which will be fully characterized. Finally, new identities
between the central factorials and the Euler polynomials are found.Comment: also available at http://cmup.fc.up.pt/cmup/ since the 2nd August
201
A note on maximal estimates for stochastic convolutions
In stochastic partial differential equations it is important to have pathwise
regularity properties of stochastic convolutions. In this note we present a new
sufficient condition for the pathwise continuity of stochastic convolutions in
Banach spaces.Comment: Minor correction
The Red Sea, Coastal Landscapes, and Hominin Dispersals
This chapter provides a critical assessment of environment, landscape and resources in the Red Sea region over the past five million years in relation to archaeological evidence of hominin settlement, and of current hypotheses about the role of the region as a pathway or obstacle to population dispersals between Africa and Asia and the possible significance of coastal colonization. The discussion assesses the impact of factors such as topography and the distribution of resources on land and on the seacoast, taking account of geographical variation and changes in geology, sea levels and palaeoclimate. The merits of northern and southern routes of movement at either end of the Red Sea are compared. All the evidence indicates that there has been no land connection at the southern end since the beginning of the Pliocene period, but that short sea crossings would have been possible at lowest sea-level stands with little or no technical aids. More important than the possibilities of crossing the southern channel is the nature of the resources available in the adjacent coastal zones. There were many climatic episodes wetter than today, and during these periods water draining from the Arabian escarpment provided productive conditions for large mammals and human populations in coastal regions and eastwards into the desert. During drier episodes the coastal region would have provided important refugia both in upland areas and on the emerged shelves exposed by lowered sea level, especially in the southern sector and on both sides of the Red Sea. Marine resources may have offered an added advantage in coastal areas, but evidence for their exploitation is very limited, and their role has been over-exaggerated in hypotheses of coastal colonization
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