7,283 research outputs found
The New Hemoglobinopathies
The clinical explorations which have resulted from studies of mutant hemoglobin have allowed definition of a variety of syndromes whose manifestations require explanation in terms of the effects of molecular distortion on physiological processes. The discovery of various hemoglobinopathies has demonstrated that specific molecular defects may express themselves in various pathophysiological manifestations. More detailed pathophysiological studies of patients with hemoglobinopathies should be performed to gain a better understanding of the expression of molecular disease
THE PROPOSED UNITED STATES ADMINISTRATIVE COURT, PART II
The recent movement for the passage of the Logan bill and the establishment of supervisory tribunals for the control of administrative determinations is the result of several preconceived theories concerning the shortcomings of the present system of administrative justice. These underlying theories, cautiously surrounded by a halo of judicial philosophy, have seldom been analyzed in their relation to the development of a sound policy for the administration of governmental functions. The present installment of this article will be devoted first to an examination of these fundamental theories and a consideration of the question how far the present administrative machinery is inadequate to meet existing needs. Then will follow a further analysis of the jurisdictional provisions of the bill to discover whether they are adapted to accomplish the purposes expressed by the sponsors and drafters of the proposed legislation or materially contribute to the development of a sounder system of governmental administration
THE PROPOSED UNITED STATES ADMINISTRATIVE COURT
The last half century has witnessed a constant, almost relentless, increase of governmental responsibilities and services in both federal and state spheres of control. Due to the changing needs of our economic and social order, the desire for speedy, efficient and inexpensive settlement of controversies and the imperative need of specialized administrators, the task of performing these new functions has not infrequently been delegated to administrative tribunals or commissions. Neither the legislature nor the judiciary was capable of administering the myriad details or countless controversies which inevitably accompanied these new functions of government. As a consequence an administrative branch of the government made its appearance in everything except name-at first merely as an offshoot of the executive department, but finally as a series of independent establishments. Consequently, some writers have expressed the view that there is a fourth power of government in addition to the orthodox tripartite division. Under this expanding system of public administration, the administrative tribunal has become a great deal more than a mere machine for the application of law. It was inevitable that the function of administration pass beyond the routine enforcement of law to the more substantial responsibilities involved in the creation of law and the determination of private rights as an integral part of the administrative process
Repeatability of \u3cem\u3eIn Vivo\u3c/em\u3e Parafoveal Cone Density and Spacing Measurements
Purpose. To assess the repeatability and measurement error associated with cone density and nearest neighbor distance (NND) estimates in images of the parafoveal cone mosaic obtained with an adaptive optics scanning light ophthalmoscope (AOSLO).Methods. Twenty-one participants with no known ocular pathology were recruited. Four retinal locations, approximately 0.65[degrees] eccentricity from the center of fixation, were imaged 10 times in randomized order with an AOSLO. Cone coordinates in each image were identified using an automated algorithm (with or without manual correction) from which cone density and NND were calculated. Owing to naturally occurring fixational instability, the 10 images recorded from a given location did not overlap entirely. We thus analyzed each image set both before and after alignment.Results. Automated estimates of cone density on the unaligned image sets showed a coefficient of repeatability of 11,769 cones/mm2 (17.1%). The primary reason for this variability appears to be fixational instability, as aligning the 10 images to include the exact same retinal area results in an improved repeatability of 4358 cones/mm2 (6.4%) using completely automated cone identification software. Repeatability improved further by manually identifying cones missed by the automated algorithm, with a coefficient of repeatability of 1967 cones/mm2 (2.7%). NND showed improved repeatability and was generally insensitive to the undersampling by the automated algorithm.Conclusions. As our data were collected in a young, healthy population, this likely represents a best-case estimate for corresponding measurements in patients with retinal disease. Similar studies need to be carried out on other imaging systems (including those using different imaging modalities, wavefront correction technology, and/or image analysis software), as repeatability would be expected to be highly sensitive to initial image quality and the performance of cone identification algorithms. Separate studies addressing intersession repeatability and interobserver reliability are also needed
Dissipation and Tunnelling in Quantum Hall Bilayers
We discuss the interplay between transport and intrinsic dissipation in
quantum Hall bilayers, within the framework of a simple thought experiment. We
compute, for the first time, quantum corrections to the semiclassical dynamics
of this system. This allows us to re-interpret tunnelling measurements on these
systems. We find a strong peak in the zero-temperature tunnelling current that
arises from the decay of Josephson-like oscillations into incoherent charge
fluctuations. In the presence of an in-plane field, resonances in the
tunnelling current develop an asymmetric lineshape.Comment: 4 pages, 3 figure
Symbolic Powers of Monomial Ideals
We investigate symbolic and regular powers of monomial ideals. For a
square-free monomial ideal in we show
is a subset of for all
positive integers , and , where is the big-height of and . This captures two conjectures ( and ): one of
Harbourne-Huneke and one of Bocci-Cooper-Harbourne. We also introduce the
symbolic polyhedron of a monomial ideal and use this to explore symbolic powers
of non-square-free monomial ideals.Comment: 15 pages. Fixed typ
Evaluating Outer Segment Length as A Surrogate Measure of Peak Foveal Cone Density
Adaptive optics (AO) imaging tools enable direct visualization of the cone photoreceptor mosaic, which facilitates quantitative measurements such as cone density. However, in many individuals, low image quality or excessive eye movements precludes making such measures. As foveal cone specialization is associated with both increased density and outer segment (OS) elongation, we sought to examine whether OS length could be used as a surrogate measure of foveal cone density. The retinas of 43 subjects (23 normal and 20 albinism; aged 6–67 years) were examined. Peak foveal cone density was measured using confocal adaptive optics scanning light ophthalmoscopy (AOSLO), and OS length was measured using optical coherence tomography (OCT) and longitudinal reflectivity profile-based approach. Peak cone density ranged from 29,200 to 214,000 cones/mm2(111,700 ± 46,300 cones/mm2); OS length ranged from 26.3 to 54.5 μm (40.5 ± 7.7 μm). Density was significantly correlated with OS length in albinism (p \u3c 0.0001), but not normals (p = 0.99). A cubic model of density as a function of OS length was created based on histology and optimized to fit the albinism data. The model includes triangular cone packing, a cylindrical OS with a fixed volume of 136.6 μm3, and a ratio of OS to inner segment width that increased linearly with increasing OS length (R2 = 0.72). Normal subjects showed no apparent relationship between cone density and OS length. In the absence of adequate AOSLO imagery, OS length may be used to estimate cone density in patients with albinism. Whether this relationship exists in other patient populations with foveal hypoplasia (e.g., premature birth, aniridia, isolated foveal hypoplasia) remains to be seen
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