8,771 research outputs found
A comparison of methods to evaluate energy expenditure of incubating wandering albatrosses
Measurements of incubation energetics can vary depending on the method used to measure metabolism of an incubating bird. Therefore, we evaluated the energy expenditure of six male and four female wandering albatrosses (Diomedea exulans Linnaeus) using doubly labeled water (DLW), the rate of mass loss, and estimates of metabolic water production derived from water influx rate (WIR). Incubation metabolic rates (IMR) determined with DLW ( 169 ± 21 kJ kg d SD) were significantly lower than estimates derived from mass loss ( 277 ± 46kJ kg d SD) and WIR ( males=289 ± 60 kJ kg d vs. females = 400 ± 69 kJ kg d SD). Estimates of IMR from f WIR were similar to IMR (305 ± 39 kJ kg d SD) determined by respirometry in a previous study, and IMR from DLW was similar to estimates based on heart rate (HR; 147 ± 26 kJ d SD) determined in another study. Ap- 147 26 plying the different measurements of IMR to construct an en-ergy budget, we estimate that a breeding pair of wandering albatrosses spends 124--234 MJ to incubate the egg for 78 d. Finally, IMRs determined with DLW and HR were similar
Atom Based Vector Microwave Electrometry Using Rubidium Rydberg Atoms in a Vapor Cell
It is clearly important to pursue atomic standards for quantities like
electromagnetic fields, time, length and gravity. We have recently shown, using
Rydberg states, that Rb atoms in a vapor cell can serve as a practical, compact
standard for microwave electric field strength. Here, we demonstrate, for the
first time, that Rb atoms excited in a vapor cell can also be used for vector
microwave electrometry by using Rydberg atom electromagnetically induced
transparency. We describe the measurements necessary to obtain an arbitrary
microwave electric field polarization at a resolution of . The
experiments are compared to theory and found to be in excellent agreement
On Optimality of Stepdown and Stepup Multiple Test Procedures
Consider the multiple testing problem of testing k null hypotheses, where the
unknown family of distributions is assumed to satisfy a certain monotonicity
assumption. Attention is restricted to procedures that control the familywise
error rate in the strong sense and which satisfy a monotonicity condition.
Under these assumptions, we prove certain maximin optimality results for some
well-known stepdown and stepup procedures.Comment: Published at http://dx.doi.org/10.1214/009053605000000066 in the
Annals of Statistics (http://www.imstat.org/aos/) by the Institute of
Mathematical Statistics (http://www.imstat.org
Photoionization Rates of Cs Rydberg Atoms in a 1064 nm Far Off-Resonance Trap
Experimental measurements of photoionization rates of Rydberg
states of Cs () in a 1064 nm far off-resonance dipole trap
are presented. The photoionization rates are obtained by measuring the
lifetimes of Rydberg atoms produced inside of a 1064 nm far off-resonance trap
and comparing the lifetimes to corresponding control experiments in a
magneto-optical trap. Experimental results for the control experiments agree
with recent theoretical predictions for Rydberg state lifetimes and measured
photoionization rates are in agreement with transition rates calculated from a
model potential.Comment: 12 pages, 4 figure
Observation of blue-shifted ultralong-range Cs Rydberg molecules
We observe ultralong-range blue-shifted Cs molecular states near
Rydberg states in an optical dipole trap, where .
The accidental near degeneracy of and Rydberg states for in
Cs, due to the small fractional quantum defect, leads to non-adiabatic
coupling among these states, producing potential wells above the
thresholds. Two important consequences of admixing high angular momentum states
with states are the formation of large permanent dipole moments, Debye, and accessibility of these states via two-photon association.
The observed states are in excellent agreement with theory. Both projections of
the total angular momentum on the internuclear axis are visible in the
experiment
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