Classical optical lithography is diffraction limited to writing features of a size lambda/2 or greater, where lambda is the optical wavelength. Using nonclassical photon-number states, entangled N at a time, we show that it is possible to write features of minimum size lambda/(2N) in an N-photon absorbing substrate. This result allows one to write a factor of N2 more elements on a semiconductor chip. A factor of N = 2 can be achieved easily with entangled photon pairs generated from optical parametric down-conversion. It is shown how to write arbitrary 2D patterns by using this method.

Objective. To determine the risk and causes of death and to quantify mortality predictors in patients with rheumatoid arthritis (RA).Methods. RA patients (n = 3,501) from 4 centers (Saskatoon n = 905, Wichita n = 1,405, Stanford n = 886, and Santa Clara n = 305) were followed for up to 35 years; 922 patients died.Results. The overall standardized mortality ratio (SMR) was 2.26 (Saskatoon 2.24, Wichita 1.98, Stanford 3.08, Santa Clara 2.18) and increased with time. Mortality was strikingly increased for specific causes: infection, lymphoproliferative malignancy, gastroenterologic, and RA. In addition, as an effect of the SMR of 2.26, the expected number of deaths was increased nonspecifically across all causes (except cancer), with a large excess of deaths attributable to cardiovascular and cerebrovascular diseases. Independent predictors of mortality included age, education, male sex, function, rheumatoid factor, nodules, erythrocyte sedimentation rate, joint count, and prednisone use.

In order to demonstrate non-trivial quantum computations experimentally, such as the synthesis of arbitrary entangled states, it will be useful to understand how to decompose a desired quantum computation into the shortest possible sequence of one-qubit and two-qubit gates. We contribute to this effort by providing a method to construct an optimal quantum circuit for a general two-qubit gate that requires at most 3 CNOT gates and 15 elementary one-qubit gates. Moreover, if the desired two-qubit gate corresponds to a purely real unitary transformation, we provide a construction that requires at most 2 CNOTs and 12 one-qubit gates. We then prove that these constructions are optimal with respect to the family of CNOT, y-rotation, z-rotation, and phase gates.

We demonstrate that two spatially separated parties (Alice and Bob) can utilize shared prior quantum entanglement, and classical communications, to establish a synchronized pair of atomic clocks. In contrast to classical synchronization schemes, the accuracy of our protocol is independent of Alice's or Bob's knowledge of their relative locations or of the properties of the intervening medium.

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We evaluated methods of grading radiologic progression of osteoarthritis (OA). Sets of radiographs were assessed separately by 8 readers who were blinded to the time sequence. Included were radiographs of patients with OA of the hands (24 pairs), hips (40 pairs), and knees (32 pairs). Most films were taken 1240 months apart. The relative contribution of individual joints (such as particular interphalangeal joints), of observations (such as narrowing or spurs), and of a single joint compartment (such as the medial or lateral compartment of the knee) toward evidence of OA progression Submitted for publication September 30, 1986; accepted in revised form April 9, 1987. was evaluated, as well as the reliability and concordance of scoring, and the sensitivity in detecting change. In assessing OA of the hand, the greatest sensitivity was achieved by reading a single posteroanterior bilateral hand radiograph for narrowing, spurs, and erosions, and scoring 10 joints (second and third distal interphalangeal, second and third proximal interphalangeal, and trapeziometacarpal joints, bilaterally), using a scale of 0-3. In OA of the hip, a single anteroposterior radiograph assessed for joint space narrowing and cyst formation yielded the greatest sensitivity. In OA of the knee, an anteroposterior radiograph, with weight-bearing, assessed for narrowing, spurs, and sclerosis in both the medial and lateral compartments yielded the greatest sensitivity. These techniques will be useful to the investigator in designing experimental studies and to the clinician in determining the rate of disease progression in an individual patient.Standards for the radiographic identification of osteoarthritis (OA) were established by Kellgren and Lawrence in 1957 (1) and were accepted by the World Health Organization in 1961 (2). In several recent descriptions of the radiographic appearance of OA, clinical and pathologic correlations have been used to help differentiate OA from normal states and from other disease entities (3-6). However, there are no methods presently available to assess radiographic progression of OA by use of serial radiographs.Radiographs are frequently used in clinical trials of OA to establish inclusion criteria. However, such trials have not used radiographs to assess disease progression. The consistency of OA progression is not known. The reasons for not utilizing radiographs to evaluate progression in long-term trials are, perhaps,

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