Quantum metrology timing limits of the Hong-Ou-Mandel interferometer and of general two-photon measurements

We examine the precision limits of Hong-Ou-Mandel (HOM) timing measurements, as well as precision limits applying to generalized two-photon measurements. As a special case, we consider the use of two-photon measurements using photons with variable bandwidths and frequency correlations. When the photon bandwidths are not equal, maximizing the measurement precision involves a trade-off between high interference visibility and strong frequency anticorrelations, with the optimal precision occuring when the photons share non-maximal frequency anticorrelations. We show that a generalized measurement has precision limits that are qualitatively similar to those of the HOM measurement whenever the generalized measurement is insensitive to the net delay of both photons. By examining the performance of states with more general frequency distributions, our analysis allows for engineering of the joint spectral amplitude for use in realistic situations, in which both photons may not have ideal spectral properties.Comment: 12 pages, 6 figures; resubmissio

Evaluation of Soybean Varieties in the Northern Uniform Soybean Test

The Northern Uniform Soybean Test is used to evaluate soybean varieties produced by several public breeding programs in the Northern portion of the United States and Canada. In 2009, five public breeding programs participated in the Northern Uniform Soybean Test (Maturity Group I). Public breeders are allowed to enter varieties in the Uniform Test in exchange for growing locations for the test. Material entered in the Uniform Test is generally from advanced stages of a breeding program. The Uniform Soybean Test is an efficient method for soybean breeders to get multiple location data in comparison to each individual program growing their own locations. It also produces useful information by comparing soybean lines from multiple programs and identifies lines from other states that produce well in northern Iowa. Results from these tests are used by breeders to select varieties with superior yield and/or disease resistance to continue advancement to variety release. These results are also used to demonstrate positive characteristics to growers and other interested parties

Evaluation of Soybean Varieties in the Northern Uniform Soybean Test—Uniform Test III

The Northern Uniform Soybean Test is used to evaluate soybean varieties produced by several public breeding programs in the northern portion of the United States and Canada. In 2010, five public breeding programs participated in the Northern Uniform Soybean Test (Uniform Test III). Public breeders are allowed to enter varieties into the Uniform Test in exchange for growing locations for the test. Material entered into the Uniform Test is generally in advanced stages of a breeding program. The Uniform Soybean Test is a method for soybean breeders to get multiple location data, in a very efficient manner in comparison to each individual program growing their own locations. It also produces useful information by comparing soybean lines from multiple programs, and identifies lines from other states that produce well in southern Iowa. Results from these tests are used by breeders to select varieties with superior yield and/or disease resistance to continue advancement on a trek toward variety release. These results are also used to demonstrate positive characteristics to growers and other interested parties

Evaluation of Soybean Varieties in the Northern Uniform Soybean Test—Uniform Test III

The Northern Uniform Soybean Test is used to evaluate soybean varieties produced by several public breeding programs in the northern portion of the United States and Canada. In 2010, five public breeding programs participated in the Northern Uniform Soybean Test (Uniform Test III). Public breeders are allowed to enter varieties into the Uniform Test in exchange for growing locations for the test. Material entered into the Uniform Test is generally in advanced stages of a breeding program. The Uniform Soybean Test is a method for soybean breeders to get multiple location data, in a very efficient manner in comparison to each individual program growing their own locations. It also produces useful information by comparing soybean lines from multiple programs, and identifies lines from other states that produce well in southern Iowa. Results from these tests are used by breeders to select varieties with superior yield and/or disease resistance to continue advancement on a trek toward variety release. These results are also used to demonstrate positive characteristics to growers and other interested parties.</p

Evaluation of Soybean Varieties in the Northern Uniform Soybean Test—Uniform Test I

The Northern Uniform Soybean Test is used to evaluate soybean varieties produced by several public breeding programs in the northern portion of the United States and Canada. In 2010, five public breeding programs participated in the Northern Uniform Soybean Test (Uniform Test I). Public breeders are allowed to enter varieties into the Uniform Test in exchange for growing locations for the test. Material entered into the Uniform Test is generally in advanced stages of a breeding program. The Uniform Soybean Test is an efficient method for soybean breeders to get multiple location data, in a very efficient manner in comparison to each individual program growing their own locations. It also produces useful information by comparing soybean lines from multiple programs, and identifies lines from other states that produce well in northern Iowa. Results from these tests are used by breeders to select varieties with superior yield and/or disease resistance to continue advancement on a trek toward variety release. These results are also used to demonstrate positive characteristics to growers and other interested parties.</p

Evaluation of Soybean Varieties in the Northern Uniform Soybean Test

The Northern Uniform Soybean Test is used to evaluate soybean varieties produced by several public breeding programs in the Northern portion of the United States and Canada. In 2009, five public breeding programs participated in the Northern Uniform Soybean Test (Maturity Group I). Public breeders are allowed to enter varieties in the Uniform Test in exchange for growing locations for the test. Material entered in the Uniform Test is generally from advanced stages of a breeding program. The Uniform Soybean Test is an efficient method for soybean breeders to get multiple location data in comparison to each individual program growing their own locations. It also produces useful information by comparing soybean lines from multiple programs and identifies lines from other states that produce well in northern Iowa. Results from these tests are used by breeders to select varieties with superior yield and/or disease resistance to continue advancement to variety release. These results are also used to demonstrate positive characteristics to growers and other interested parties.</p

Stress response of a marine ammonia-oxidizing archaeon informs physiological status of environmental populations.

High representation by ammonia-oxidizing archaea (AOA) in marine systems is consistent with their high affinity for ammonia, efficient carbon fixation, and copper (Cu)-centric respiratory system. However, little is known about their response to nutrient stress. We therefore used global transcriptional and proteomic analyses to characterize the response of a model AOA, Nitrosopumilus maritimus SCM1, to ammonia starvation, Cu limitation and Cu excess. Most predicted protein-coding genes were transcribed in exponentially growing cells, and of ~74% detected in the proteome, ~6% were modified by N-terminal acetylation. The general response to ammonia starvation and Cu stress was downregulation of genes for energy generation and biosynthesis. Cells rapidly depleted transcripts for the A and B subunits of ammonia monooxygenase (AMO) in response to ammonia starvation, yet retained relatively high levels of transcripts for the C subunit. Thus, similar to ammonia-oxidizing bacteria, selective retention of amoC transcripts during starvation appears important for subsequent recovery, and also suggests that AMO subunit transcript ratios could be used to assess the physiological status of marine populations. Unexpectedly, cobalamin biosynthesis was upregulated in response to both ammonia starvation and Cu stress, indicating the importance of this cofactor in retaining functional integrity during times of stress