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Context. The collisional thick target model (CTTM) of solar hard X-ray (HXR) bursts has become an almost “standard model” of flare impulsive phase energy transport and radiation. However, it faces various problems in the light of recent data, particularly the high electron beam density and anisotropy it involves.

Aims. We consider the polarization arising from scattering in an envelope illuminated by a central anisotropic source. This work extends the theory introduced in a previous paper (Al-Malki et al. 1999) in which scattering polarization from a spherically symmetric envelope illuminated by an anisotropic point source was considered. Here we generalize to account for the more realistic expectation of a non-spherical envelope shape.

Context. Hard X-ray bremsstrahlung continuum spectra, such as from solar flares, are commonly described in terms of power-law fits, either to the photon spectra themselves or to the electron spectra responsible for them. In applications various approximate relations between electron and photon spectral indices are often used for energies both above and below electron low-energy cutoffs.

Aims.X-ray properties of the stellar population in the Carina OB1 association are examined with special emphasis on early-type stars. Their spectral characteristics provide some clues to understanding the nature of X-ray formation mechanisms in the winds of single and binary early-type stars.

Aims.We investigate the signature of the photospheric albedo contribution in solar flare hard X-ray spectra, the effect of low energy cutoffs in electron spectra, and the directivity of hard X-ray emission.

Context.During the 14th/15th of April 2002, several flares occurred in NOAA active region complex 9893/9910. Two of these were previously interpreted as having anomalously high coronal column densities.

The observed hard X-ray (HXR) flux spectrum $I(\epsilon)$from solar flares is a combination of primary bremsstrahlung photons $I_{\rm P}(\epsilon)$with a spectrally modified component from photospheric Compton backscatter of downward primary emission. The latter can be significant, distorting or hiding the true features of the primary spectrum which are key diagnostics for acceleration and propagation of high energy electrons and of their energy budget. For the first time in solar physics, we use a Green's function approach to the backscatter spectral deconvolution problem, constructing a Green's matrix including photoelectric absorption. This approach allows spectrum-independent extraction of the primary spectrum for several HXR flares observed by the Ramaty High Energy Solar Spectroscopic Imager(RHESSI). We show that the observed and primary spectra differ very substantially for flares with hard spectra close to the disk centre. We show in particular that the energy dependent photon spectral index $\gamma (\epsilon)=-{\rm d} \log I/{\rm d} \log \epsilon$is very different for $I_{\rm P}(\epsilon)$and for $I(\epsilon)$and that inferred mean source electron spectra ${\overline F}(E)$differ greatly. Even for a forward fitting of a parametric ${\overline F}(E)$to the data, a clear low-energy cutoff required to fit $I(\epsilon)$essentially disappears when the fit is to $I_{\rm P}(\epsilon)$– i.e. when albedo correction is included. The self-consistent correction for backscattered photons is thus shown to be crucial in determining the energy spectra of flare accelerated electrons, and hence their total number and energy.

The hot star wind momentum problem $\eta=\dot{M} v_{\infty}/(L/c) \gg 1$is revisited, and it is shown that the conventional belief, that it can be solved by a combination of clumping of the wind and multiple scattering of photons, is not self-consistent for optically thick clumps. Clumping does reduce the mass loss rate $\dot{M}$, and hence the momentum supply, required to generate a specified radio emission measure ε, while multiple scattering increases the delivery of momentum from a specified stellar luminosity L. However, in the case of thick clumps, when combined the two effects act in opposition rather than in unison since clumping reduces multiple scattering. From basic geometric considerations, it is shown that this reduction in momentum delivery by clumping more than offsets the reduction in momentum required, for a specified ε. Thus the ratio of momentum deliverable to momentum required is maximal for a smooth wind and the momentum problem remains for the thick clump case. In the case of thin clumps, all of the benefit of clumping in reducing ηlies in reducing $\dot{M}$for a given εso that extremely small filling factors $f\approx 10^{-4}$are needed. 
It is also shown that clumping affects the inference of $\mbox{$\dot{M}$}$from radio εnot only by changing the emission measure per unit mass but also by changing the radio optical depth unity radius $R_{\rm {rad}}$, and hence the observed wind volume, at radio wavelengths. In fact, for free-free opacity $\propto n^2$, contrary to intuition, $R_{\rm {rad}}$increases with increasing clumpiness.

The Discrete Absorption Components (DACs) commonly observed in the ultraviolet lines of hot stars have previously been modelled by dynamical simulations of Corotating Interaction Regions (CIRs) in their line-driven stellar winds. Here we apply the kinematic DAC inversion method of Brown et al. to the hydrodynamical CIR models and test the reliability of the results obtained. We conclude that the inversion method is able to recover valuable information on the velocity structure of the mean wind and to trace movement of velocity plateaux in the hydrodynamical data, though the recovered density profile of the stream is correct only very near to the stellar surface.

The information content of data on rotationally periodic recurrent discrete absorption components (DACs) in hot star wind emission lines is discussed. The data comprise optical depths $\tau(w,\phi)$as a function of dimensionless Doppler velocity $w=(\Delta\lambda/\lambda_0)(c/v_\infty)$and of time expressed in terms of stellar rotation angle ϕ. This is used to study the spatial distributions of density, radial and rotational velocities, and ionisation structures of the corotating wind streams to which recurrent DACs are conventionally attributed.
The simplifying assumptions made to reduce the degrees of freedom in such structure distribution functions to match those in the DAC data are discussed and the problem then posed in terms of a bivariate relationship between $\tau(w,\phi)$and the radial velocity $v_{{\rm r}}(r)$, transverse rotation rate $\Omega(r)$and density $\rho(r,\phi)$structures of the streams. The discussion applies to cases where: the streams are equatorial; the system is seen edge on; the ionisation structure is approximated as uniform; the radial and transverse velocities are taken to be functions only of radial distance but the stream density is allowed to vary with azimuth. The last kinematic assumption essentially ignores the dynamical feedback of density on velocity and the relationship of this to fully dynamical models is discussed. The case of narrow streams is first considered, noting the result of Hamann et al. ([CITE]) that the apparent acceleration of a narrow stream DAC is higherthan the acceleration of the matter itself, so that the apparent slow acceleration of DACs cannot be attributed to the slowness of stellar rotation. Thus DACs either involve matter which accelerates slower than the general wind flow, or they are formed by structures which are not advected with the matter flow but propagate upstream (such as Abbott waves). It is then shown how, in the kinematic model approximation, the radial speed of the absorbing matter can be found by inversion of the apparent acceleration of the narrow DAC, for a given rotation law.
The case of broad streams is more complex but also more informative. The observed $\tau(w,\phi)$is governed not only by $v_{{\rm r}}(r)$and $\Omega(r)$of the absorbing stream matter but also by the density profile across the stream, determined by the azimuthal ($\phi_0$) distribution function $F_0(\phi_0)$of mass loss rate around the stellar equator. When $F_0(\phi_0)$is fairly wide in $\phi_0$, the acceleration of the DAC peak $\tau(w,\phi)$in wis generally slow compared with that of a narrow stream DAC and the information on $v_{{\rm r}}(r)$, $\Omega(r)$and $F_0(\phi_0)$is convoluted in the data $\tau(w,\phi)$.
We show that it is possible, in this kinematic model, to recover by inversion, complete information on all three distribution functions $v_{{\rm r}}(r)$, $\Omega(r)$and $F_0(\phi_0)$from data on $\tau(w,\phi)$of sufficiently high precision and resolution since $v_{{\rm r}}(r)$and $\Omega(r)$occur in combination rather than independently in the equations. This is demonstrated for simulated data, including noise effects, and is discussed in relation to real data and to fully hydrodynamic models.

We present XMM-Newton results for the X-ray spectrum from the N-rich Wolf-Rayet (WR) star WR 1. The EPIC instrument was used to obtain a medium-resolution spectrum. The following features characterize this spectrum: (a) significant emission “bumps” appear that are coincident with the wavelengths of typical strong lines, such as Mgxi, Sixiii, and Sxv; (b) little emission is detected above 4 keV, in contrast to recent reports of a hard component in the stars WR 6 and WR 110 which are of similar subtype; and (c) evidence for sulfur K-edge absorption at about 2.6 keV, which could only arise from absorption of X-rays by the ambient stellar wind. The lack of hard emission in our dataset is suggestive that WR 1 may truly be a single star, thus representing the first detailedX-ray spectrum that isolates the WR wind alone (in contrast to colliding wind zones). Although the properties of the S-edge are not well-constrained by our data, it does appear to be real, and its detection indicates that at least some of the hot gas in WR 1 must reside interior to the radius of optical depth unity for the total absorptive opacity at the energy of the edge.

We analyse the RHESSI photon spectra of four flares that exhibit significant deviations from power laws – i.e. changes in the “local” Hard X-ray spectral index. These spectra are characterised by two regions of constant power law index connected by a region of changing spectral index – the “knee”. We develop theoretical and numerical methods of describing such knees in terms of variable photon spectral indices and we study the results of their inversions for source mean thin target and collisional thick target injection electron spectra. We show that a particularly sharp knee can produce unphysical negative values in the electron spectra, and we derive inequalities that can be used to test for this without the need for an inversion to be performed. Such unphysical features would indicate that source model assumptions were being violated, particularly strongly for the collisional thick target model which assumes a specific form for electron energy loss. For all four flares considered here we find that the knees do not correspond to unphysical electron spectra. In the three flares that have downward knees we conclude that the knee can be explained in terms of transport effects through a region of non-uniform ionisation. In the other flare, which has an upward knee, we conclude that it is most likely a feature of the accelerated spectrum.

The carbon-rich WC5 star WR 114 was not detected during a 15.9 ksec XMM-Newtonobservation, implying an upper limit to the X-ray luminosity of LX$\lesssim\,2.5\times 10^{30}$erg s-1and to the X-ray to bolometric luminosity ratio of LX/Lbol$\lesssim\,4\times10^{-9}$. This confirms indications from earlier less sensitive measurements that there has been no convincing X-ray detection of any single WC star. This lack of detections is reinforced by XMM-Newtonand Chandraobservations of WC stars. Thus the conclusion has to be drawn that the stars with radiatively-driven stellar winds of this particular class are insignificant X-ray sources. We attribute this to photoelectronic absorption by the stellar wind. The high opacity of the metal-rich and dense winds from WC stars puts the radius of optical depth unity at hundreds or thousands of stellar radii for much of the X-ray band. We believe that the essential absence of hot plasma so far out in the wind exacerbated by the large distances and correspondingly high ISM column densities makes the WC stars too faint to be detectable with current technology. The result also applies to many WC stars in binary systems, of which only about 20% are identified X-ray sources, presumably due to colliding winds.

We calculate multicomponent line-driven wind models of stars at extremely low metallicity suitable for massive first generation stars. For most of the models we find that the multicomponent wind nature is not important for either wind dynamics or for wind temperature stratification. However, for stars with the lowest metallicities we find that multicomponent effects influence the wind structure. These effects range from pure heating to possible fallback of the nonabsorbing wind component. We present a simple formula for the calculation of metallicity for which the multicomponent effects become important. We show that the importance of the multicomponent nature of winds of low metallicity stars is characterised not only by the low density of driving ions, but also by lower mass-loss rate.

Spectral lines formed in stellar winds from OB stars are observed to exhibit profile variations. Discrete Absorption Components (DACs) show a remarkably slow wavelength drift with time. In a straightforward interpretation, this is in sharp contradiction to the steep velocity law predicted by the radiation-driven wind theory, and by semi-empirical profile fitting. In the present paper we re-discuss the interpretation of the drift rate. We show that the Co-rotating Interaction Region (CIR) model for the formation of DACs does not explain their slow drift rate as a consequence of rotation. On the contrary, the apparent acceleration of a spectral CIR feature is even higher than for the corresponding kinematical model without rotation. However, the observations can be understood by distinguishing between the velocity field of the matter flow, and the velocity law for the motion of the patternsin which the DAC features are formed. If the latter propagate upstream against the matter flow, the resulting wavelength drift mimics a much slower acceleration although the matter is moving fast. Additional to the DACs, a second type of recurrent structures is present in observed OB star spectra, the so-called modulations. In contrast to the DACs, these structures show a steep acceleration compatible with the theoretically predicted velocity law. We see only two possible consistent scenarios. Either, the wind is accelerated fast, and the modulations are formed in advected structures, while the DACs come from structures which are propagating upstream. Or, alternatively, steep and shallow velocity laws may co-exist at the same time in different spatial regions or directions of the wind.

We describe X-ray production in the atmospheres of hot, early-type stars in the framework of a "stochastic shock model" . The extended envelope of a star is assumed to possess numerous X-ray emitting "hot" zones that are produced by shocks and embedded in the ambient "cold" medium in dynamical equilibrium. It is shown that the apparent lack of X-ray variability on short (~ hours) timescales do not contradict a shock model for X-ray production. The character of the X-ray variability is found to depend on the frequency with which hot zones are generated, the cool wind opacity to X-rays, and the wind flow parameters, such as mass loss rate and terminal speed.

The instability properties of bremsstrahlung spectrum inversion to yield source electron spectra in flares are examined in terms of singular value decomposition (SVD) for the cases of thin- and thick-target models for different bremsstrahlung cross-sections. It is shown that, for the Kramers and Bethe-Heitler cross-sections, analytic expressions can be obtained for evaluation of the Gram matrix. These allow quantitative comparison of the instability of inversion for each case and hence assessment of the accuracy and resolution of the electron source function recovery. Based on this analysis we find that: (a) the solution instability is worse for the Bethe-Heitler than for the Kramers approximation; care must therefore be taken in real data analysis to use the most accurate possible cross-section to avoid over- or under-estimating the maximum precision and resolution achievable in the recovered electron spectrum; (b) instability is worse in recovering thick-target injection spectra than thin-target mean source spectra, as expected because of the double deconvolution involved in the former; (c) such SVD analysis should form an important part of future analysis of high resolution flare data such as from the HESSI Mission.

Throughout biology, cells and organisms use flagella and cilia to propel fluid and achieve motility. The beating of these organelles, and the corresponding ability to sense, respond to and modulate this beat is central to many processes in health and disease. While the mechanics of flagellum–fluid interaction has been the subject of extensive mathematical studies, these models have been restricted to being geometrically linear or weakly nonlinear, despite the high curvatures observed physiologically. We study the effect of geometrical nonlinearity, focusing on the spermatozoon flagellum. For a wide range of physiologically relevant parameters, the nonlinear model predicts that flagellar compression by the internal forces initiates an effective buckling behaviour, leading to a symmetry-breaking bifurcation that causes profound and complicated changes in the waveform and swimming trajectory, as well as the breakdown of the linear theory. The emergent waveform also induces curved swimming in an otherwise symmetric system, with the swimming trajectory being sensitive to head shape—no signalling or asymmetric forces are required. We conclude that nonlinear models are essential in understanding the flagellar waveform in migratory human sperm; these models will also be invaluable in understanding motile flagella and cilia in other systems.

Miscanthusspp. are high‐yielding perennial C4grasses, native to Asia, that are being investigated in Europe as potential biofuels. Production of economically viable solid biofuel must combine high biomass yields with good combustion qualities. Good biomass combustion quality depends on minimizing moisture, ash, K, chloride, N, and S. To this end, field trials at five sites in Europe from Sweden to Portugal were planted with 15 different genotypes including M.× giganteus, M. sacchariflorus, M. sinensis, and newly bred M. sinensishybrids. Yield and combustion quality at an autumn and a late winter/early spring harvest were determined in the third year after planting when the stands had reached maturity. As expected, delaying the harvest by three to four months improved the combustion quality of all genotypes by reducing ash (from 40 to 25 g kg−1dry matter), K (from 9 to 4 g kg−1dry matter), chloride (from 4 to 1 g kg−1dry matter), N (from 5 to 4 g kg−1dry matter), and moisture (from 564 to 291 g kg−1fresh matter). However, the delayed harvest also decreased mean biomass yields from 17 to 14 t ha−1. There is a strong interaction among yield, quality, and site growing conditions. Results show that in northern regions of Europe, M. sinensishybrids can be recommended for high yields (yielding up to 25 t ha−1), but M. sinensis(nonhybrid) genotypes have higher combustion qualities. In mid‐ and south Europe, M.× giganteus(yielding up to 38 t ha−1) or specific high‐yielding M. sinensishybrids (yielding up to 41 t ha−1) are more suitable for biofuel production.

ABSTRACTDespite the discovery of Epstein-Barr virus more than 35 years ago, a thorough understanding of gammaherpesvirus capsid composition and structure has remained elusive. We approached this problem by purifying capsids from Kaposi's sarcoma-associated herpesvirus (KSHV), the only other known human gammaherpesvirus. The results from our biochemical and imaging analyses demonstrate that KSHV capsids possess a typical herpesvirus icosahedral capsid shell composed of four structural proteins. The hexameric and pentameric capsomers are composed of the major capsid protein (MCP) encoded by open reading frame 25. The heterotrimeric complexes, forming the capsid floor between the hexons and pentons, are each composed of one molecule of ORF62 and two molecules of ORF26. Each of these proteins has significant amino acid sequence homology to capsid proteins in alpha- and betaherpesviruses. In contrast, the fourth protein, ORF65, lacks significant sequence homology to its structural counterparts from the other subfamilies. Nevertheless, this small, basic, and highly antigenic protein decorates the surface of the capsids, as does, for example, the even smaller basic capsid protein VP26 of herpes simplex virus type 1. We have also found that, as with the alpha- and betaherpesviruses, lytic replication of KSHV leads to the formation of at least three capsid species, A, B, and C, with masses of approximately 200, 230, and 300 MDa, respectively. A capsids are empty, B capsids contain an inner array of a fifth structural protein, ORF17.5, and C capsids contain the viral genome.

Background. CD4⁺ T cells are important mediators in the pathogenesis of rheumatoid arthritis (RA). In this open-label, dose-escalating study, we examined the pharmacokinetic (PK), clinical, biological and immunological effects of a humanized IgG1 anti-CD4 monoclonal antibody (mAb), 4162W94, in the peripheral blood (PB) and synovial fluid (SF) of RA patients.
Method. Twenty-four patients in four cohorts (six patients in each cohort) were allocated to be treated with five consecutive daily doses of 4162W94 (10, 30, 100 or 300 mg i.v.). Disease activity was measured by the American College of Rheumatology (ACR) criteria and disease activity score (DAS). We also measured 4162W94 concentration, the percentage of 4162W94-coated CD4⁺ lymphocytes, percentage down-modulation of CD4, interleukin-6 (IL-6) and tumour necrosis factor α (TNFα) levels in the PB and SF.
Results. A direct relationship between 4162W94 dose, biological response and clinical outcome was seen. Treatment with 10 and 30 mg of 4162W94 for 5 consecutive days resulted in transient coating and down-modulation of CD4⁺ lymphocytes, with little effect observed beyond the final dose. However, treatment with 100 and 300 mg resulted in sustained coating and/or down-modulation for 3 weeks and 4 weeks, respectively, in PB and >4 weeks in SF in one patient from the 300 mg cohort. There was a dose-related moderate but transient depression in the CD4⁺ lymphocyte count in most patients, with all but three returning to >0.40 × 10⁹/l or >75% baseline by the end of the study period. Significant clinical improvement (ACR 20%) was seen in only 1/6 patients in each of the 10- and 30-mg cohorts; however, 3/6 and 5/5 patients in the 100 and 300-mg cohorts, respectively, were ACR 20% responders. In addition, there were significant reductions in PB acute phase reactants as well as SF IL-6 and TNFα concentrations in parallel to clinical improvement.
Conclusion. Data from this pilot study suggest that 4162W94 is a clinically active novel immunotherapeutic agent that may suppress inflammation in RA.

Grain characteristics and groat composition have been evaluated in 35 genotypes from nine taxonomic species of Avena, including three species (A. agadiriana, A. atlantica, A. damascena) for which no previous data are available. There was substantial interspecific and intraspecific variation for all characteristics measured. The proportion of groat in the grain ranged from 32·7–62·1%, and mean groat weight from 2·4–37·4 mg. Groat protein concentrations ranged from 13·9–41·3%, and exceeded 32% in one A. atlantica, two A. damascena and one A. murphyi genotype. Groat β-glucan concentration showed very wide variation (2·2–11·3%) are there were substantial interspecific and intraspecific differences. The highest β-glucan concentrations were found in genotypes of A. atlantica. Although there were interspecific and intraspecific variations in groat oil concentration (4·2–10·6%), and in fatty acid composition, data were within previously reported ranges for A. sativa. Overall these data indicate that some of the genotypes of the wild species studied may be of value for breeding oats with improved levels of β-glucan and protein, and that further studies are warranted into both interspecific and intraspecific variations in grain quality factors in wild oat species.

We consider the hard x-ray emission process by interaction between the electrons and the ions in the solar atmosphere. We provide the integral equations describing this process as an inverse problem in the case of uniform ionization of the plasma and of a simple but rather realistic approximation of non-uniform conditions. The singular system of the integral operators is computed analytically in the continuous case for the uniform ionization model and numerically in the case of discrete data for both uniform and non-uniform ionization conditions. By analytical arguments and analysis of the singular spectrum we point out that non-uniform ionization results in an ambiguous interpretation of the solution of the integral equation, this solution not being unique. Finally, we briefly recall that this analysis facilitates methods for recovering unique and regularized solutions from high-resolution hard x-ray spectral data soon to be forthcoming from the HESSI space mission.

Sorghum (Sorghum bicolorL. Moench) is often grown on alkaline soils, and the plants frequently develop symptoms of Fe deficiency. The susceptibility is dependent on the ability of the plant to respond to Fe stress. This adaptive response is genetically controlled whereby H+ions and a reductant are released from the roots. These make Fe available for uptake by the plant. Activation is greatest in Fe‐efficient plants and least in Fe‐inefficient plants. Phosphate accumulation and Fe‐stress response oppose each other in plant use of Fe. In this study, accumulation of phosphate and Fe‐stress response were evaluated as causes of Fe chlorosis in four sorghum cultivars that differ in uptake of P and in susceptibility to Fe chlorosis. The seedlings were first grown in a light chamber on a complete nutrient solution at, pH 4.3 until the plants were large enough for use. They were then transferred to nutrient solutions with Fe, P, NH4‐N or NO3‐N as variables. The pH of the nutrient solution, reductant in nutrient solution, and uptake of Fe and P by the plant were determined. The Fe‐efficient KS5 and ‘Pioneer 846’ sorghums released more reductant from their roots, took up more Fe, and contained less P than the Fe‐inefficient “B‐line” and ‘Wheatland’ cultivars. The release of H+ions by roots was somewhat comparable in all four sorghum lines. On Bladen soil (pH 4.3—high in Al), KS5 and Pioneer 846 took up less P than the “B‐line” and Wheatland sorghum. Phosphorus efficiency in the four cultivars is “B‐line” ≥ Wheatland > Pioneer‐846 > KS5. In addition, KS5 developed iron chlorosis, which implies that KS5 cannot utilize either P or Fe in Bladen soil. Accumulation of P and insufficient Fe‐stress response both appear to be causative factors of Fe deficiency in “B‐line” and Wheatland sorghum.

Alfalfa (Medicago sativaL., ‘DuPuits’, F.C. 40247) is a cultivar of the Flemish type selected on a clay‐loam soil in northern France. It matures early and grows rapidly after each cutting, but little is known about its nutrient requirements. The objective of this study was to determine the nutrient requirements or tolerance of DuPuits alfalfa for specific elements. It was subjected to Fe, Zn, and Cu stresses, and to Mn and Al toxiclties by growing it on seven soils known to produce these deficiency or toxicity symptoms in other crops. DuPuits alfalfa developed severe Zn deficiency symptoms on most alkaline soils, Al toxicity symptoms on acid Bladen soil, and Mn toxicity symptoms on acid Richland soil. When lime was added to the two acid soils, the plants developed Cu deficiency symptoms on Bladen (pH 5.3) and deficiency symptoms on Richland (pH 7.0). The deficiency symptoms were corrected by adding Cu and B to these soils, respectively. DuPuits alfalfa absorbed and transported Fe from the alkaline soils and it never developed Fe deficiency symptoms.

Fifteen cotton varieties (Gossypium hirsutumL.), representing germplasm recommended for different areas of the United States, were subjected to Fe, Zn, and Cu stresses and Al and Mn toxicities to determine their nutrient requirements. They were grown on the seven different soils described in part I of this study for soybeans. All cotton varieties grown on Quinlan soil (Fe stress) developed deficiency symptoms that were similar to symptoms produced in cotton grown on Shano and Taunton soils (Zn stress). On Quinlan and Taunton soils, the plants responded to both Fe and Zn. Iron added to Taunton soil decreased the uptake of Fe and increased the uptake of Zn by the plants. Lime added to Richland soil induced a Zn deficiency that increased Fe uptake by the plants. When Zn was added to this soil, yields increased and Fe uptake decreased in the plants. All 15 cotton varieties grew poorly on acid Bladen soil (Al toxic), and yields were doubled by liming and yield of C‐7105, 73‐319 doubled again by adding Cu. Best yields, with no toxicity symptoms, were obtained on Richland soil (Mn toxic). Cotton and soybean had different nutrient requirements. For example, cotton was Cu and Zn inefficient and Mn tolerant, whereas soybeans were Cu and Zn efficient and Mn intolerant in most varieties tested.

Fifteen sorghum (Sorghum bicolor(L.) Moench) lines, representing diverse germplasm currently used in crop breeding programs in the United States, were grown on the seven soils, used in part I of this study, to produce Fe, Zn, and Cu stresses or Al and Mn toxicities in soybeans. All 15 sorghum lines developed Fe and Zn deficiencies with symptoms ranging from some interveinal chlorosis to necrotic and twisted leaf tips. The sorghum lines responded differentially to Cu stress. When Cu was added to the soil, yields increased and P, Fe, and Zn concentrations significantly decreased in the plant material. The sorghum lines responded differentially to Al in Bladen soil. Five lines grew poorly and developed a chlorosis with some purple pigmentation; five lines were green and made good growth; and five lines were intermediate in their response. The chlorotic lines contained significantly less Fe and P than the green sorghum. On Richland soil (high Mn), yields were relatively good and the sorghum plants did not develop any persistent toxicity symptoms. Care should be taken to select the sorghum line best adapted to Fe, Zn, or Cu stresses and to Al toxicity so that the plant and the soil may be compatible.

Plant species and varieties within species differ in their response to mineral stresses and toxicities. To achieve maximum yields, the plant and the soil must be compatible. In the past, the soil has been changed to fit the plant. In this study, we consider changing the plant to fit the soil, recognizing that plant species and varieties within species have specific nutrient requirements. Ten soybean (Glycine max(L.) Merr.) varieties, representing the germplasm currently used in soybean production in the United States, were subjected to Fe, Zn, and Cu stresses; and Mn and Al toxicities to determine their nutrient requirements or tolerance to mineral elements. Seven soils, which had produced the above nutrient stresses and toxicities in other crops, were used in this study. The soybean varieties showed a differential response to Fe stress by developing severe (‘Forrest’), moderate (‘Hodgson’), or no Fe chlorosis (‘Bragg’). Leaves dropped from Forrest and Bragg soybeans as they developed severe Mn toxicity symptoms. In contrast, ‘Lee’ soybean developed only slight Mn toxicity symptoms. Most soybean varieties grew well when subjected to Zn and Cu stresses, or when grown on Al‐toxic soil. Care should be taken to select the proper soybean variety to be grown on soils where Fe stress or Mn toxicity may be a problem.

Soybeans (Glycine maxL. Merr.) differ in their tolerance to Mn. The objective of this study was to determine the nature or mode of inheritance of Mn tolerance in soybeans. Test plants were Forrest (Mn‐intolerant, Fe‐inefficient), T203 (Mn‐tolerant, Fe‐inefficient) and their F2progeny Forrest × T203 (F×T) and T203 × Forrest (T×F); and Bragg (Mn‐intolerant, Fe‐efficient), Lee (Mn‐tolerant, mod. Fe efficient) and their F2progeny, Bragg × Lee (B×L), and Lee × Bragg (L×B). The plants were grown in Mn‐toxic soil and in nutrient solutions containing 0.35 and 0.65 mg Mn/liter. Only T203 did not develop some Mn‐toxicity symptoms under conditions of relatively high Mn. The order of symptom severity was Forrest ≥ Bragg > Lee > T203. Manganese toxicity symptoms also varied among the F2progeny of reciprocal crosses. The leaves of both parents and progenies contained about 500 mg Mn/g dry matter. Some factor(s) other than Mn concentration in the plants appeared to cause the Mn‐toxicity symptoms. The Fe concentration in plant tops was related somewhat to Mn‐toxicity symptoms in that the Fe concentrations were usually greater in Mn‐intolerant than in Mn‐tolerant genotypes. Control of tolerance to excess Mn appeared to be multgenic rather than controlled by a single gene locus. Reciprocal differences in progeny suggested that cytoplasmic inheritance influenced Mn tolerance. Crop failure can be avoided by selecting a Mn‐tolerant soybean to be grown in a soil relatively high in available Mn.

Plants have specific Fe requirements, dependent on their ability to make Fe available in a useful form. They are classed Fe‐efficient if they respond to Fe‐deficiency stress by inducing biochemical reactions that make Fe available in a useful form, and Fe‐inefficient if they do not. This study was conducted to characterize the use of Fe by Fe‐inefficient oats (Avena byzantinaK. Koch) ‘TAM 0‐312,’ and Fe‐efficient oats ‘Coker 227.’ These cultivars were grown in nutrient solutions where they were subjected to different degrees of Fe stress induced by variable concentrations of either phosphate, CaCO3, or Fe. The oat plants were grown in an environmentally‐controlled chamber with 16 hours of light at approximately 320 µEm‐3sec‐1and 8 hours of darkness at a temperature of 24 ± 2 C. Coker 227 was more Fe‐efficient than TAM 0‐312 regardless of how Fe stress was induced and usually contained less Ca than TAM 0‐312. TAM 0.312 required 1.2 mg Fe/liter in the nutrient solution before it was green, whereas Coker 227 required only 0.6 mg Fe/liter. Susceptibility to Fe chlorosis in these cultivars was caused by the inherent nature of the plant to use either Fe8+or F2+and by the greater use of Ca by TAM 0‐312 than by Coker 227. The plant plays a key role in maintaining a proper nutrient elememt balance and the availability of a nutrient element for plant use.

Plant species differ in their response to light; some grow best in full sunlight, some in partial shade, and others in full shade. Inside, under growth chamber conditions, cool white fluorescent (CWF) lamps, in combination with supplemental incandescent (Inc) lamps, have been a satisfactory light source. Low pressure sodium (UPS) lamps have also been used. The spectral radiant power curve for the CWF lamps extends from 350 (includes UV and blue) to above 700 nm, whereas the spectral curve for LPS lamps is between 560 to 610 nm (no UV or blue) with no radiation below 550 nm. This study was conducted to determine affect of LPS and CWF lamps, alone and in combination with Inc lamps, on plant growth and reduction of Fe3+to Fe2+. Lettuce (Lactuca salivaL. ‘Grand Rapids’), cotton (Gossypium hirsutumL. ‘M8’) and petunia (Petunia hybridaVilm. ‘Pink Cascade’) were grown in environmental control cabinets at 22 and 28 C under LPS or CWF lamps, with and without Inc lamps. Reduction of Fe3+to Fe2+was determined as Fe2+ferrorine [disodium salt of 3‐(2‐pyridyl)‐ 5,6‐bis(4‐phenylsulfonic acid‐l,2,4‐triazine] in solution under all light treatments to determine if chlorophyll concentration in plant tops was related to Fe3+reduction in solution. We had observed that cotton was chlorotic under LPS, but not under CWF lamps. Only small amounts of Fe3+were reduced to Fe2+at wavelengths above 420 nm, and more Fe3+was reduced to Fe2+in solution under CWF than under LPS lamps. Chlorophyll concentration in lettuce and cotton leaves followed about the same pattern as Fe3+reduced to Fe2+in solution. Chlorophyll levels were greater in leaves grown under CWF than under LPS lamps, and generally greater in leaves grown at 28 than at 22 C. If we assume that CWF light mediates reduction of Fe3+to Fe2+in plant foliage as it does in ferric‐ferrozine solutions then it could make Fe2+available for biochemical reactions related to chlorophyll synthesis. Petunia did not respond to the light regimes and temperature as did lettuce and cotton.

Twelve (Sorghum bicolorL. Moench) genotypes were grown on acid‐Bladen soil (pH 4.3, P stressed or Al toxic), on limed‐Bladen soil (pH 5.2, Cu stressed), and on alkaline Quinlan soil (pH 7.5, Fe stressed) to determine the effect of P efficiency on use of these clements by the plants. Under P‐stress or Al‐toxicity conditions, the most P‐efficient sorghum genotypes absorbed more 32P than the most P‐inefficient lines and grew normally, while the P‐inefficient plants developed P‐deficiency symptoms. Under Fe‐stress conditions, the most P‐efficient genotypes developed Fe chlorosis, while the most P‐inefficient plants remained green. Under Cu‐stress conditions, one of six genotypes developed severe Cu‐deficiency symptoms, characterized by the accumulation of higher P in the lower leaves, and by lower Fe and Ca in upper leaves of Cu‐stressed plants as compared with Cu‐sufficient plants. Thus, P efficiency in plants may be an asset when P availability limits growth, but it may be a liability when these same plants are subjected to Fe or Cu stress.

An intense and fast spike-like solar burst was observed with high sensitivity in microwaves and hard X-rays, on December 18,1980, at 19h21m20s UT. It is shown that the burst was built up of short time scale structures superimposed on an underlying gradual emission, the time evolution of which showed remarkable proportionality between hard X-ray and microwave fluxes. The finer time structures were best defined at mm-microwaves. At the peak of the event the finer structures repeat every 30–60 ms (displaying an equivalent repetition rate of 16–20 s-1). The more slowly varying component with a time scale of about 1 s was identified in microwaves and hard X-rays throughout the burst duration. Similarly to what has been found for mm-microwave burst emission, we suggest that X-ray fluxes might also be proportional to the repetition rate of basic units of energy injection (quasi-quantized). We estimate that one such injection produces a pulse of hard X-ray photons with about 4 × 1021 erg, for ? ? 25 keV. We use this figure to estimate the relevant parameters of one primary energy release site both in the case where hard X-rays are produced primarily by thick-target bremsstrahlung, and when they are purely thermal, and also discuss the relation of this figure to global energy considerations. We find, in particular, that a thick-target interpretation only becomes possible if individual pulses have durations larger than 0.2 s.

Host plant resistance to insects has become a major breeding objective in cotton (Gossypium hirsutumL.), since significant increases in resistance may result simultaneously in yield increases and reduced usage of insecticides. Nectariless ‘Acala’ cotton strains with reduced pubescence are being developed in an attempt to gain significant host plant resistance against harmful Lepidoptera. Extensive studies were undertaken to evaluate the first‐order effects that the nectariless and reduced pubescence plant modifications would have upon oviposition behavior of three key insects. Cage trials with pink bollworms (Pectinophora gossypiella) have been difficult to manage and results are inconclusive. It was found that cabbage loopers (Trichoplusia ni) showed a slight increase in oviposition on nectariless cottons with reduced pubescence. The increase was so small as to be of doubtful economic importance. Paired isolation cage studies conducted over a 4‐year period showed that similar numbers of Heliothis zeamoths laid only 45% as many eggs on nectariless Acala strains as on their normally hairy, nectaried companion lines. There was a disturbing reversal in form in certain tests, due to variables not yet clearly understood. However, there was a clear trend indicating that the suppression of oviposition is greatest when environmental conditions are most favorable for a bollworm epidemic. This large reduction of egg numbers at peak oviposition is the strongest confirmation of the value of developing nectariless cottons to minimize Heliothisdamage.

Oat (Avena byzantinaC. Koch) cultivars ‘TAM 0‐312’ (Fe‐inefficient and Ca‐efficient) and ‘Coker 227’ (Feefficient) were subjected to Zn and Cu stresses to determine consequent effects on Fe and Ca nutrition in the two cultivars. To induce Zn and Cn stress, the plants were grown in low‐Zn Taunton and Shano soils, and in low‐Cu limed Bladen soil. Under zinc stress, Coker 227 used Fe more efficiently than TAM 0‐312. TAM 0‐312 tops contained 3600 µg/g (dry wt) more Ca than comparable Coker 227 tops and this higher Ca seemed to enhance both Fe‐ and Zn‐deficiency symptoms in TAM 0‐312. Top leaves of Cu‐stressed TAM 0‐312 contained 4300 µg/g (dry wt) more P than comparable Coker 227 leaves. This Cu‐deficiency stress induced accumulation of phosphate seemed to inactivate Ca in TAM 0‐312, causing ‘withertip’ to develop. Coker 227 did not develop ‘withertip’ symptoms. Ca‐efficiency did not alleviate Cu‐inefficiency in TAM 0‐312.

Oat (Arena byzantinaC. Koch) cultivars developed differential Fe chlorosis symptoms when grown in field trials on alkaline soils in south Texas. To determine why they differed, ‘TAM 0‐312’ (Fe‐inefficient), ‘Coker 227’ (Fe‐efficlent), and ‘TAM 0‐301’ and ‘73C1952’ (intermediate in Fe response) oats were tested in alkaline soils and in nutrient solutions. Physiologically, Coker 227 responded more favorably to Fe stress (reduced Fe3+to Fe2+at the root) than TAM 0‐312. More significantly, the Ca concentration was consistently about 2,500 µg/g dry matter greater in TAM 0‐312 than in Coker 227. Although not consistent, the P concentration was often greater in TAM 0‐312 than in Coker 227 which would also accentuate Fe chlorosis. We suggest that Ca effectively competes with or inactivates Fe in TAM 0‐312, thus causing Fe chlorosis to develop in this cultivar but not in Coker 227.

The corn (Zea maysL.) inbreds Pa36 and WH (reported to be high and low P accumulators, respectively, when grown in soils) were tested for differences in P uptake from nutrient solutions. Phosphorus efficiency for the two inbreds was tested by inducing P stresses in two ways: 1) by varying the amount of P added to the nutrient medium, and 2) by adding varied quantities of A1 to the nutrient medium at a given level of P. The more P‐efficient inbred Pa36 took up and accumulated higher amounts of P than WH when grown separately or together with WH in the same container. Dry matter yields for WH were comparable or higher than Pa36 when grown at various levels of P, but under Al‐induced P stress conditions, Pa36 yielded higher than WH. Regardless of the method of P stress, Pa36 yielded more dry matter than WH when both inbreds were grown together in the same container. WH roots decreased the solution pH faster than Pa36 roots under all P stress conditions. The increased amount of active A1 at the lower solution pH affected WH roots more adversely than Pa36 roots. Intact Pa36 roots exhibited higher phosphatase activity than WH roots when grown at various levels of P.

The problem of synchrotron radiation spectra is treated from the viewpoint of deconvolving the spectrum of ultrarelativistic source electrons from the observed photon spectrum. It is shown that for homogeneous sources the problem amounts to inversion of a Meijer transform with a modified Bessel finction kernel. A precise analytic inversion is only possible in the complex plane but Meijer transform tables are available for a wide range of functions. More convenient inversion formulae prove possible by use of a Laplace transform approximation or by analysing the spectra in terms of their integral moments.

The jet/grain model proposed by Ramatyet al. (1984, hereafter abbreviated as RKL) for production of the narrow gamma-ray lines reported from SS433 is examined and shown to be untenable on numerous grounds. Most importantly:(a)The huge Coulomb collisional losses (Wc?2×1041 erg s-1) from the jet, which would necessarily accompany non-thermal production of the gamma rays, demands a jet acceleration/collimation process acting over a very long range and with a power at least 102 times the Eddington limit for any stellar object.(b)There is a collisional thick target limit (irrespective of jet mass) to the gamma ray yield per interstellar proton. Consequently, the gamma-ray data demand an improbably high interstellar density (?109 cm-3).(c)For the grains to be kept cool enough (?3000 K) to survive the heating rateWc either by radiation or jet expansion would demand a ‘jet’ wider than its length and so inconsistent with narrow lines. In the case of radiative cooling, the resultant IR flux would exceed the observed values by a factor ?104.(d)Light scattered on the jet grain mass required would be highly polarized, contrary to observations, unless the jet was optically thick to grains, again precluding their radiative cooling.(e)To avoid unacceptable precessional broadening of the gamma-ray lines demands an emitting jet length ?0.5 days atv=0.26c. This increases the necessary mass loss rate by a factor ?10 over the values obtained by RKL who assumed a 4-day ‘flare’.(f)The model also predicts rest energy gamma-ray lines which are not observed.

Calcitonin gene-related peptide-like immunoreactivity was demonstrated in in sensory nerve fibers in the epidermis and dermis as free nerve endings and around blood vessels and hair follicles of the human finger pad and arm skin. The vast majority of the calcitonin generelated immunoreactive fibers was shown to display also substance P-like immunoreactivity and a few fibers in the dermis were somatostatin positive. No fibers displaying both substance P and somatostatin-like immunoreactivity were found but a few substance P immunoreactive fibers in the dermis-epidermis region were found to contain also vasointestinal polypeptide-like immunoreactivity. In the sweat glands, abundant calcitonin gene-related peptide positive, but substance P negative, fibers were observed with a similar distribution pattern as the vasoactive intestinal polypeptide immunoreactive fibers and these fibers were suggested to be of sympathetic origin.

Somatostatin-like immunoreactivity was detected within the adrenal gland of the rat using specific monoclonal antibodies. Immunohistochemical studies demonstrated a few somatostatin-immunoreactive nerve fibers within the adrenal medulla. In addition, a large population of chromaffin cells in the cat adrenal medulla displayed intense somatostatin-like immunoreactivity. Similar cells were not observed in rat or guinea pig adrenal glands, although they were found in human material. The somatostatin-positive cells in the cat adrenal medulla often possessed short immunoreactive processes similar to those seen in somatostatin-immunoreactive paracrine cells of the gut. Characterization of the somatostatin-like immunoreactivity of the cat adrenal by high performance liquid chromatography and radioimmunoassay indicated that somatostatin-28 may account for over 90% of the observed immunoreactivity. It is suggested that somatostatin-28 may have a paracrine or endocrine role in the feline adrenal medulla.

A monoclonal antibody raised to gastric inhibitory polypeptide (GIP) has been compared with conventional rabbit and guinea-pig antisera to GIP. Four staining methods were tested and of these the peroxidase antiperoxidase (PAP) method proved to give the best results with both the mouse and rabbit antibodies. The monoclonal antibody, when used to stain pancreatic tissue, gave negative results whereas a distinct population of gut endocrine cells was readily demonstrable, suggesting that GIP is not a constituent of the mammalian pancreas. The monoclonal antibody was found to be the most sensitive for immunocytochemistry achieving the titre of 1:106 in rat gut. A C-terminal specific antibody, with a high affinity and avidity to GIP, it was clearly the preferred antibody for immunocytochemical studies.