Quantum Rotation Sensing with Dual Sagnac Interferometers in an Atom-Optical Waveguide.

We describe a Sagnac interferometer suitable for rotation sensing, implemented using an atomic Bose-Einstein condensate confined in a harmonic magnetic trap. The atom wave packets are split and recombined by standing-wave Bragg lasers, and the trapping potential steers the packets along circular trajectories with a radius of 0.2 mm. Two conjugate interferometers are implemented simultaneously to provide common-mode rejection of noise and to isolate the rotation signal. With interference visibilities of about 50%, we achieve a rotation sensitivity comparable to Earth's rate in about 10 min of operation. Gyroscope operation was demonstrated by rotating the optical table on which the experiment was performed.

A member of the KNOTTED class of homeodomain proteins encoded by the STM gene of Arabidopsis.

The KNOTTED class of plant genes encodes homeodomain proteins. These genes have been found in all plant species where they have been sought and, where examined, show expression patterns that suggest they play an important role in shoot meristem function. Until now, all mutant phenotypes associated with these genes have been due to gain-of-function mutations, making it difficult to deduce their wild-type function. Here we present evidence that the Arabidopsis SHOOT-MERISTEMLESS (STM) gene, required for shoot apical meristem formation during embryogenesis, encodes a class I KNOTTED-like protein. We also describe the expression pattern of this gene in the wild-type plant. To our knowledge, STM is the first gene shown to mark a specific pattern element in the developing plant embryo both phenotypically and molecularly.

Altered metaphase chromosome structure in xrs-5 cells is not related to its radiation sensitivity or defective DNA break rejoining.

The chinese hamster ovary (CHO) cell line xrs-5 is a radiation-sensitive derivative of CHO-K1 cells. The xrs-5 cells have a defect in DNA double-strand break rejoining and show alterations in chromosome structure and nuclear morphology. The relationship between radiation sensitivity and metaphase chromosome morphology was examined in 12 'revertant' xrs-5 clones isolated following treatment with 5-azacytidine. nine of the clones were radioresistant while the other three retained xrs-5-like radiation sensitivity. Chromosome morphology reverted to CHO-K1-like characteristics in three of the radioresistant clones and one of the radiosensitive clones suggesting that the over-condensed metaphase chromosome morphology of xrs-5 cells does not underlie its radiation sensitivity. Radiation sensitivity did correlate with DNA double-strand break rejoining ability. The radioresistant clones showing the over-condensed xrs-5-like chromosome morphology were also slightly more sensitive to the topoisomerase II inhibitor etoposide (VP-16) than CHO-K1, suggesting that the over-condensed morphology might be due to alterations in the phosphorylation of chromatin proteins.

Metaphase chromosome and nucleoid differences between CHO-K1 and its radiosensitive derivative xrs-5.

The Chinese hamster ovary (CHO) cell line xrs-5 is a radiation-sensitive mutant isolated from CHO-K1 cells. The radiation sensitivity is associated with a defect in DNA double-strand break rejoining. Chromatin structure also appears altered in xrs-5 cells compared with the parental CHO-K1 cells. Metaphase chromosomes from xrs-5 are more condensed in appearance than CHO-K1 chromosomes. The overcondensed look is not the result of colcemid sensitivity. Electron microscopy studies suggest that xrs-5 metaphase chromosomes have larger loops of chromatin extending out from the chromosome core. There are also differences between CHO-K1 and xrs-5 cells in the size and fluorescence pattern of ethidium bromide-stained nucleoid preparations. These results suggest that there is a fundamental difference between CHO-K1 and xrs-5 in either the organization of the supercoiled loops of DNA attached to the nuclear matrix or in the nature of the proteins that attach the DNA to the matrix. These alterations in chromosome structure may underlie, in part, the radiation sensitivity of xrs-5 cells.

Faster rates of DNA unwinding under alkaline conditions in xrs-5 cells may reflect chromatin structure alterations.

The Chinese hamster ovary (CHO) cell line xrs-5 is a radiation-sensitive mutant isolated from CHO-K1 cells. The radiation sensitivity is associated with a defect in DNA double-strand break rejoining. The DNA alkaline unwinding technique was used to measure the DNA single-strand breakage caused by gamma-rays in xrs-5 and CHO-K1 cells. Greater rates of DNA unwinding were found in xrs-5 cells as compared to CHO-K1. Independent measurement of DNA strand breakage by DNA filter elution or pulsed-field gel electrophoresis failed to show any difference between the two cell lines. The greater rate of unwinding in xrs-5 cells may reflect an alteration in chromosome structure.

Comparative survey of psychiatrists' prescription preferences: New York and Texas.

The present survey compares the treatment preferences of New York and Texas psychiatrists using a questionnaire report of a single psychiatric case. The characteristics of this approach enable the investigator to hold and symptoms and syndromes of the patient constant. All clinicians respond to identical stimuli. What varies naturally, then, is the judgment of the clinician in developing his treatment procedure, thereby enabling estimation of the degree of standardization in treatment preferences. Three hundred twelve psychiatrists from New York and 133 from Texas provided data for comparative purposes. On the first admission 41% of the New York respondents and 24% of the Texas psychiatrists preferred a regimen that included more than one drug. When a combination of drugs was selected, chlorpromazine-trifluoperazine was preferred. But ten other specific combinations also were selected. Most were of potent neuroleptics, but some included antidepressant-neuroleptic combinations. None of the variables included in the study provided tangible systematic variance for these treatment preferences. A year and a half after first admission, followed by treatment in and out of hospital, the patient's clinical course continued to deteriorate. At this point more than 50% of the respondents in each state selected a regimen that included a minimum of two drugs. As many as 24 different combinations were selected for this single case. Nineteen percent of the New York respondents and 13% of the Texas respondents selected a regimen that included three or more psychoactive medications. The existence of these treatment preferences requires a more basic understanding of treatment preferences, for these seems to be no basis for them.