SHOULD WE HAVE FACULTIES OF PUBLIC HEALTH?     

Hill HW 《Science (New York, N.Y.)》1924,59(1520):153-156

Public health is the science and art of conscious physical adjustment between man and his surroundings in the universe. The modern conception of man as a product of and a part of nature brings the subject of man's individual physical adjustments with his immediate surroundings into its proper place as the fundamental study-the basis of every form of education. Hence, public health is not only eligible for a position as an independent faculty in any university but is as definitely entitled to such a place as any of those now recognized. It is futile to consider the ordinary 45 hour course in public health, furnished as an incident in the ordinary 4000 to 5000 hour medical course, as more than a smattering, offered to medical students alone, of the 900 to 4500 hour courses in public health offered to professional public health students.  相似文献   

Language pollution     

Hill PA 《Science (New York, N.Y.)》1970,169(3945):534

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Crystal structure of defensin HNP-3, an amphiphilic dimer: mechanisms of membrane permeabilization   总被引：34，自引：0，他引：34  

C P Hill  J Yee  M E Selsted  D Eisenberg 《Science (New York, N.Y.)》1991,251(5000):1481-1485

Defensins (molecular weight 3500 to 4000) act in the mammalian immune response by permeabilizing the plasma membranes of a broad spectrum of target organisms, including bacteria, fungi, and enveloped viruses. The high-resolution crystal structure of defensin HNP-3 (1.9 angstrom resolution, R factor 0.19) reveals a dimeric beta sheet that has an architecture very different from other lytic peptides. The dimeric assembly suggests mechanisms by which defensins might bind to and permeabilize the lipid bilayer.  相似文献   

Welfare dependence within and across generations   总被引：2，自引：0，他引：2  

G J Duncan  M S Hill  S D Hoffman 《Science (New York, N.Y.)》1988,239(4839):467-471

A central question in the debate about the effects of welfare programs is whether their intended positive results--providing needed resources to recipients and their children--outweigh any unintended negative results--for example, the breaking up of families, reduction in work effort, or the fostering of a welfare "culture" that is passed on from parent to child. Recent research shows that although work effort is affected adversely by the generosity of welfare programs, effects on family structure appear quite weak, most welfare experiences are relatively short, and the majority of women who grew up in homes heavily dependent on welfare do not rely on those programs when they are young adults.  相似文献   

Muscle contraction and free energy transduction in biological systems   总被引：52，自引：0，他引：52  

E Eisenberg  T L Hill 《Science (New York, N.Y.)》1985,227(4690):999-1006

Muscle contraction occurs when the actin and myosin filaments in muscle are driven past each other by a cyclic interaction of adenosine triphosphate (ATP) and actin with cross-bridges that extend from myosin. Current biochemical studies suggest that, during each adenosine triphosphatase cycle, the myosin cross-bridge alternates between two main conformations, which differ markedly in their strength of binding to actin and in their overall structure. Binding of ATP to the cross-bridge induces the weak-binding conformation, whereas inorganic phosphate release returns the cross-bridge to the strong-binding conformation. This cross-bridge cycle is similar to the kinetic cycle that drives active transport and illustrates the general principles of free energy transduction by adenosine triphosphatase systems.  相似文献   

Heme-heme orientation and electron transfer kinetic behavior of multisite oxidation-reduction enzymes   总被引：1，自引：0，他引：1  

M W Makinen  S A Schichman  S C Hill  H B Gray 《Science (New York, N.Y.)》1983,222(4626):929-931

Analysis of the polarized single-crystal absorption spectra of cytochrome cd1 of Pseudomonas aeruginosa shows that the heme c and heme d1 groups in each subunit are oriented perpendicularly to each other in both oxidized and reduced forms of the enzyme. These results, together with those of previous kinetic studies, indicate that a perpendicular heme-heme orientation may be an important factor in specifying kinetically slow steps in a sequential series of electron transfer reactions.  相似文献   

Saturation mutagenesis of the yeast his3 regulatory site: requirements for transcriptional induction and for binding by GCN4 activator protein   总被引：94，自引：0，他引：94  

D E Hill  I A Hope  J P Macke  K Struhl 《Science (New York, N.Y.)》1986,234(4775):451-457

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Remote sensing of the magnetic moment of uranus: predictions for voyager     

Hill TW  Dessler AJ 《Science (New York, N.Y.)》1985,227(4693):1466-1469

Power is supplied to a planet's magnetosphere from the kinetic energy of planetary spin and the energy flux of the impinging solar wind. A fraction of this power is available to drive numerous observable phenomena, such as polar auroras and planetary radio emissions. In this report our present understanding of these power transfer mechanisms is applied to Uranus to make specific predictions of the detectability of radio and auroral emissions by the planetary radio astronomy (PRA) and ultraviolet spectrometer (UVS) instruments aboard the Voyager spacecraft before its encounter with Uranus at the end of January 1986. The power available for these two phenomena is (among other factors) a function of the magnetic moment of Uranus. The date of earliest detectability also depends on whether the predominant power source for the magnetosphere is planetary spin or solar wind. The magnetic moment of Uranus is derived for each power source as a function of the date of first detection of radio emissions by the PRA instrument or auroral emissions by the UVS instrument. If we accept the interpretation of ultraviolet observations now available from the Earth-orbiting International Ultraviolet Explorer satellite, Uranus has a surface magnetic field of at least 0.6 gauss, and more probably several gauss, making it the largest or second-largest planetary magnetic field in the solar system.  相似文献   

Voyager 1 in the foreshock, termination shock, and heliosheath     

Decker RB  Krimigis SM  Roelof EC  Hill ME  Armstrong TP  Gloeckler G  Hamilton DC  Lanzerotti LJ 《Science (New York, N.Y.)》2005,309(5743):2020-2024

Voyager 1 (V1) began measuring precursor energetic ions and electrons from the heliospheric termination shock (TS) in July 2002. During the ensuing 2.5 years, average particle intensities rose as V1 penetrated deeper into the energetic particle foreshock of the TS. Throughout 2004, V1 observed even larger, fluctuating intensities of ions from 40 kiloelectron volts (keV) to >/=50 megaelectron volts per nucleon and of electrons from >26 keV to >/=350 keV. On day 350 of 2004 (2004/350), V1 observed an intensity spike of ions and electrons that was followed by a sustained factor of 10 increase at the lowest energies and lesser increases at higher energies, larger than any intensities since V1 was at 15 astronomical units in 1982. The estimated solar wind radial flow speed was positive (outward) at approximately +100 kilometers per second (km s(-1)) from 2004/352 until 2005/018, when the radial flows became predominantly negative (sunward) and fluctuated between approximately -50 and 0 km s(-1) until about 2005/110; they then became more positive, with recent values (2005/179) of approximately +50 km s(-1). The energetic proton spectrum averaged over the postshock period is apparently dominated by strongly heated interstellar pickup ions. We interpret these observations as evidence that V1 was crossed by the TS on 2004/351 (during a tracking gap) at 94.0 astronomical units, evidently as the shock was moving radially inward in response to decreasing solar wind ram pressure, and that V1 has remained in the heliosheath until at least mid-2005.  相似文献   

The Effect of Browning on the Essential Amino Acid Content of Soy Globulin     

Patton AR  Hill EG  Foreman EM 《Science (New York, N.Y.)》1948,108(2815):659-660

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