Recent recommendations for increases in desirable body weights are based upon studies which did not consider the potential confounding effect of cigarette consumption on body weight. We investigated the relation between tobacco use and several anthropometric measurements in 12,103 men and women 19-74 years of age in the United States examined between 1976 and 1980 during the Second National Health and Nutrition Examination Survey (NHANES II). Cigarette smokers weighed less (mean ± standard error = 69.8 ± 0.2 kg) and were leaner (body mass index (weight (kg)/height (m)2) = 24.6 ± 0.1) than nonsmokers (72.5 ± 0.2 kg and 25.7 ± 0. 1, respectively), controlling for age and sex. Body leanness increased with the duration (but not intensity) of smoking. Ex-smokers were not heavier or fatter than nonsmokers, and these

Because of evidence that increased body iron stores are associated with an increased risk of cancer, we examined iron status and cancer risk in the first National Health and Nutrition Examination Survey, a survey of more than 14,000 adults begun in 1971, with follow-up between 1981 and 1984. Among 242 men in whom cancer developed, the mean total iron-binding capacity was significantly lower (61.4 vs. 62.9 mumol per liter; P = 0.01) and transferrin saturation was significantly higher (33.1 vs. 30.7 percent; P = 0.002) than among 3113 men who remained free of cancer. The risk of cancer in men in each quartile of transferrin-saturation level relative to the lowest quartile was 1.00, 1.01, 1.10, and 1.37 (P = 0.02 for trend). The serum albumin level was significantly lower in men in whom cancer developed than in those who remained cancer-free. Among women, those in whom cancer developed did not have significantly lower total iron-binding capacity or higher transferrin saturation than those who remained cancer-free. However, a post hoc examination of 5367 women (203 with cancer) yielded a relative risk of 1.3 (95 percent confidence interval, 0.9 to 1.9) associated with a very high transferrin saturation (greater than or equal to 36.8 percent, a value in the highest quartile among men); in 5228 women with at least six years of follow-up (149 with cancer), the relative risk associated with transferrin saturation above this level was 1.5 (1.0 to 2.2). These results are consistent with the hypothesis that high body iron stores increase the risk of cancer in men. The possibility that a similar association exists in women requires further study.

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Power spectra from 3 × 10−4 to 0.5 cps based on Mariner 4 interplanetary magnetic field data show a dependence on frequency ƒ that is roughly of the form ƒ−γ with γ typically near 3/2 and essentially always between 1 and 2 for each of the three components and for the absolute value of the field. This is based on the analysis of data for days of widely ranging degrees of activity near solar minimum. Power levels were typically a factor of 10 higher for disturbed than for quiet days and, except on quiet days, were a factor of 2 higher for the various components than for the absolute value. Data relating to frequently occurring field discontinuities show few shocks and many contact surfaces. The associated current sheets are found to be unusually thin, roughly 50% of those analyzed had thicknesses less than 3500 km and 10% less than 500 km. The structure of the current sheets that produced the cleanest discontinuities was analyzed and shown to be consistent with that of a tangential discontinuity characterized by zero normal field and normal velocity components. The directional distribution of current sheet normals strongly suggests a local latitudinal solar wind shear that prevails over one sector and can change from sector to sector. The cross sections of magnetic filaments are found to be in some cases highly elliptical rather than more‐or‐less circular, again suggesting a latitudinal solar wind shear.

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Data obtained by the Pioneer 10 vector helium magnetometer are presented along with models of the intrinsic magnetic field of JupiteL and its magnetosphere. Data acquired between 2.84 and 6.0 Rj, where the intensity of the planetary field ranged between 1900 and 18,400 'y, were used to develop a six-parameter eccentric dipole model of the field. The dipole so derived has a moment of 4.0 G Rfi and a tilt angle With respect to Jupiter's rotation axis of 11 ø. The system I!I (epOch 1957) longitude of the magnetic pole in the northern hemisPhere,•which is a north-seeking pole, is 222 ø. The dipole is displaced from the center of Jupiter by 0.11 Ra in the direction of iatitude 16 ø and system ili longitude 176 ø. The dipole tilt and the longitude of the pole ar e in goød agreement with values inferred from radio astronomy measurements. The magnetic moment and the offset derived from the Pioneer measurements represent a significant improvement in our knowledge of the planetary field. A model of the Jovian magnetosphere is presented in which the essential feature is an eastward current sheet that forms an annulus with Jupiter at the center. At Iarge distances from the planet the current sheet is nearly parallel to Jupiter's equator but, in general, does not lie in it. The Current sheet is warped, so that it is above the equator on one side and below it on the other. The current Sheet rotates with the planet, more or less lik e a rigid body; this behavior causes an apparent up and down motion and periodic crossings of the current sheet by Pioneer. The origin of the current sheet appears to be the very large centrifugal force, associated with Jupiter's great size and rapid rotation, acting on trapped low-energy magnetospheric plasma. The density of this plasma is estimated to be approximately 1 particle cm -3. A retrograde spiraling of field lines out of meridian planes is also observed, presumably as a result of azimuthal drag forces exerted on the outer magnetosphere. INSTRUMENT DESCRIPTION The magnetometer on board Pioneer !0 is an advanced version of the vector helium magnetometer previously used on the Mai'iner 4 and 5 missions to Mars and Venus [Slocum and Reilly, 1963; Connor, 1968]. The essential elements of the magnetometer include a helium lamp, a circular polarizer, a helium absorption cell, ß Helmholtz coils, a lens, and an !R detector. The basic operation of the instrument depends upon the effect of the magnetic field direction on the efficiency with which metastable helium can be optically pumped. The presence of an ambient magnetic field causes a sine wave modulation of the IR radiation passing through the gas cell at the fundamental frequency of the applied circular sweep field. The sensor output consists of the nulling currents that are applied in order to cancel this field 'signal.'The magnetometer measures the three field components over a frequency range from 0 to 10 Hz. At encounter the data rate was 1024 bits/s and the magnetometer sampling rate, corresponding to one vector measurement every 3/16 s, ...

The properties of waves with frequencies below 3 Hz observed upstream of low Mach number (2–3) interplanetary shocks are discussed. High‐frequency emissions (0.2–2 Hz in the spacecraft frame) are commonly detected immediately upstream (<2 RE) of the shocks, whereas lower frequency emissions (∼0.05 Hz) are found to extend upstream to much greater distances (typically 10 RE). Both emissions are right‐hand circularly or elliptically polarized and generally propagate within a 15° cone angle relative to the ambient magnetic field. The lack of a significant compressional component for either of these waves is in agreement with propagation parallel to the ambient magnetic field. Upstream waves are detected principally in association with quasi‐parallel shocks (θBn < 65°). Assuming the waves are propagating outward from the shock, an expression is derived for the wave frequency in the solar wind rest frame. The waves are found to have rest frame frequencies of 0.05–1 Hz and 10−3 to 10−2 Hz. Arguments are presented which exclude the possibility that the high‐frequency waves are standing whistler mode waves. The most likely source of these emissions is generation at the shock by 100 eV to 1 keV electrons and propagation of the whistler mode waves into the upstream region. The lower frequency 10−3 to 10−2 Hz waves propagate at speeds near the Alfvén velocity, and hence cannot outrun the super‐Alfvénic shocks. These waves must be locally generated by plasma instabilities in the upstream region. Generation by Landau electrons or ions can be ruled out due to the observation of parallel propagation of the waves. The most likely source is 1–10 keV cyclotron‐resonant ions propagating away from the shock. The upstream waves bear many similarities to those observed in the earth's foreshock. The frequencies, polarization, and typical upstream extent are nearly identical. It is also deduced that the lower frequency waves of both regions are generated by keV ions streaming away from the shock. There are some differences, however. Waves upstream of interplanetary shocks are found to propagate parallel to the magnetic field (<15°), are noncompressive (ΔB/B ≤ 0.25) and are generally lower in amplitude. Additionally, there are extraordinary interplanetary events, for which the scale of the upstream wave region is greatly extended (∼1300 RE or 0.04 AU) and the field takes on a more turbulent character. The latter events should be of interest in modeling Fermi acceleration of ions at collisionless shocks.

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