Resistive-Based Micro-Kelvin Temperature Resolution for Ultra-Stable Space Experiments.

High precision temperature measurements are a transversal need in a wide area of physical experiments. Space-borne gravitational wave detectors are a particularly challenging case, requiring both high precision and high stability in temperature measurement. In this contribution, we present a design able to reach 1 µK/Hz in most of the measuring band down to 1 mHz, and reaching 20 µK/Hz at 0.1 mHz. The scheme is based on resistive sensors in a Wheatstone bridge configuration which is AC modulated to minimize the 1/f noise. As a part of our study, we include the design of a test bench able to guarantee the high stability environment required for measurements. We show experimental results characterising both the test bench and the read-out, and discuss potential noise sources that may limit our measurement.

Simultaneous laser frequency stabilization to an optical cavity and an iodine frequency reference.

In this Letter, we demonstrate a method to combine a molecular iodine absolute frequency reference with a high-finesse optical cavity in a single laser to take advantage of the frequency stability properties of both systems at different time scales. The result is a laser exhibiting the long-term and short-term stability levels of the iodine frequency reference and optical cavity, respectively. The method uses frequency offset side-band locking and an acousto-optical modulator driven ac-coupled servo-loop to correct the iodine's short-term frequency fluctuations. Experimental results show cavity-limited stability at 1 Hz of 10-151/Hz and iodine stability below 10 mHz of 10-131/Hz. In terms of the Allan deviation, this corresponds to stability levels close to the 10-15 at 1 s and 10-14 for observation times >100s.

Long-term stable optical cavity for special relativity tests in space: erratum.

We incorrectly cited a maximum acceleration sensitivity of the rigidly-mounted cavity of 2.5 × 10-10 1/(m s-2). The correct coupling factor is a factor of 100 smaller: 2.5 × 10-12 1/(m s-2).

Long-term stable optical cavity for special relativity tests in space.

BOOST (BOOst Symmetry Test) is a proposed space mission to search for Lorentz invariance violations and aims to improve the Kennedy-Thorndike parameter constraint by two orders of magnitude. The mission consists of comparing two optical frequency references of different nature, an optical cavity and a hyperfine transition in molecular iodine, in a low Earth orbit. Naturally, the stability of the frequency references at the orbit period of 5400 s (f=0.18 mHz) is essential for the mission success. Here we present our experimental efforts to achieve the required fractional frequency stability of 7.4×10-14 Hz -1/2 at 0.18 mHz (in units of the square root of the power spectral density), using a high-finesse optical cavity. We have demonstrated a frequency stability of (9±3)×10-14 Hz -1/2 at 0.18 mHz, which corresponds to an Allan deviation of 10-14 at 5400 s. A thorough noise source breakdown is presented, which allows us to identify the critical aspects to consider for a future space-qualified optical cavity for BOOST. The major noise contributor at sub-milli-Hertz frequency was related to intensity fluctuations, followed by thermal noise and beam pointing. Other noise sources had a negligible effect on the frequency stability, including temperature fluctuations, which were strongly attenuated by a five-layer thermal shield.

In-Orbit Performance of the GRACE Follow-on Laser Ranging Interferometer.

The Laser Ranging Interferometer (LRI) instrument on the Gravity Recovery and Climate Experiment (GRACE) Follow-On mission has provided the first laser interferometric range measurements between remote spacecraft, separated by approximately 220 km. Autonomous controls that lock the laser frequency to a cavity reference and establish the 5 degrees of freedom two-way laser link between remote spacecraft succeeded on the first attempt. Active beam pointing based on differential wave front sensing compensates spacecraft attitude fluctuations. The LRI has operated continuously without breaks in phase tracking for more than 50 days, and has shown biased range measurements similar to the primary ranging instrument based on microwaves, but with much less noise at a level of 1 nm/sqrt[Hz] at Fourier frequencies above 100 mHz.

Interspacecraft link simulator for the laser ranging interferometer onboard GRACE Follow-On.

Link acquisition strategies are key aspects for interspacecraft laser interferometers. We present an optical fiber-based setup able to simulate the interspacecraft link for the laser ranging interferometer (LRI) on gravity recovery and climate experiment Follow-On. It allows one to accurately recreate the far-field intensity profile depending on the mispointing between the spacecraft, Doppler shifts, and spacecraft attitude jitter. Furthermore, it can be used in late integration stages of the mission, since no physical contact with the spacecraft is required. The setup can also be easily adapted to other similar missions and different acquisition algorithms.

[The meaning of wholeness in medical philosophy]. / Was bedeutet Ganzheit in der Philosophie der Medizin?

Organisms are "wholes" insofar as togetherness with others is essential for their development and identity. The female egg is the first and original environment into which a human individual develops. The three main spheres of holistic togetherness in which man further becomes himself in joining the world are (1) psychic togetherness of the organs, (2) social togetherness with fellow human beings and (3) natural togetherness or connaturality, in the whole of nature. Health and disease can originate on any of these levels. On the first one psychosomatic experiences tend to be confirmed by recent results of psychoneuroimmunology. On the second level health or pathogenicity of private or professional social environments tend to be much better known in social medicine (public health) than in medical practice. Corresponding research on the third level is much less advanced. Medical care can be secondary to cultivating social and natural togetherness.

Human health in nature--towards a holistic philosophy of nutrition.

OBJECTIVE: To explain how the philosophy of nutrition is part of the philosophy of health. To show that this link allows practical solutions for equity and sustainability. METHOD: An analysis of the historical philosophies concerned with nutrition and health. A comparison of the definitions in the history of mind from antiquity to the beginning of the twenty-first century. CONCLUSION: We are not individually healthy, but we are so in togetherness, even with animals and plants. Comprehensive nutrition science has physical, social and environmental attributes. It follows that nutrition is good for the enhancement of good company with human beings as well as with the connatural world. We recognise that we owe to others what we are and this constitutes the equity of being.

The principles, definition and dimensions of the new nutrition science.

OBJECTIVE: To specify the principles, definition and dimensions of the new nutrition science. PURPOSE: To identify nutrition, with its application in food and nutrition policy, as a science with great width and breadth of vision and scope, in order that it can fully contribute to the preservation, maintenance, development and sustenance of life on Earth. METHOD: A brief overview shows that current conventional nutrition is defined as a biological science, although its governing and guiding principles are implicit only, and no generally agreed definition is evident. Following are agreements on the principles, definition and dimensions of the new nutrition science, made by the authors as participants at a workshop on this theme held on 5-8 April 2005 at the Schloss Rauischholzhausen, Justus-Liebig University, Giessen, Germany. RESULT: Nutrition science as here specified will retain its current 'classical' identity as a biological science, within a broader and integrated conceptual framework, and will also be confirmed as a social and environmental science. As such it will be concerned with personal and population health, and with planetary health--the welfare and future of the whole physical and living world of which humans are a part.