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A three-axis short-period seismometer has been operating on the surface of Mars in the Utopia Planitia region since September 4, 1976. During the first 5 months of operation, approximately 640 hours of high quality data, uncontaminated by lander or wind noise, have been obtained. The detection threshold is estimated to be magnitude 3 to about 200 km and about 6.5 for the planet as a whole. No large events have been seen during this period, a result indicating that Mars is less seismically active than earth. Wind is the major source of noise during the day, although the noise level was at or below the sensitivity threshold of the seismometer for most of the night during the early part of the mission. Winds and therefore the seismic background started to intrude into the nighttime hours starting on sol 119 (a sol is a Martian day). The seismic background correlates well with wind velocity and is proportional to the square of the wind velocity, as is appropriate for turbulent flow. The seismic envelope power spectral density is proportional to frequency to the -0.66 to -0.90 power during windy periods. A possible local seismic event was detected on sol 80. No wind data were obtained at the time, so a wind disturbance cannot be ruled out. However, this event has some unusual characteristics and is similar to local events recorded on earth through a Viking seismometer system. If it is interpreted as a natural seismic event, it has a magnitude of 3 and a distance of 110 km. Preliminary interpretation of later arrivals in the signal suggest a crustal thickness of 15 km at the Utopia Planitia site which is within the range of crustal models derived from the gravity field. More events must be recorded before a firm interpretation can be made of seismicity or crustal structure. One firm conclusion is that the natural background noise on Mars is low and that the wind is the prime noise source. It will be possible to reduce this noise by a factor of 10^3 on future missions by removing the seismometer from the lander, operation of an extremely sensitive seismometer thus being possible on the surface.

Three nodulation-deficient (nod) mutants of Rhizobium leguminosarum were isolated following insertion of the transposon Tn5 into pRL1JI, the R. leguminosarum plasmid known to carry the nodulation genes. DNA adjacent to the nod: Tn5 alleles was subcloned and used to probe a cosmid clone bank containing DNA from a Rhizobium strain carrying pRL1JI. Two cosmid clones which showed homology with the probe contained about 10 kb of DNA in common. The R. leguminosarum host-range determinants were found to be present within this 10 kb common region since either of the cosmid clones could enable a cured R. phaseoli strain to nodulate peas instead of Phaseolus beans, its normal host. Electron microscopy of nodules induced by Rhizobium strains cured of their normal symbiotic plasmid but containing either of the two cosmid clones showed bacteroid-forms surrounded by a peri-bacteroid membrane, indicating that normal infection had occurred. Thus it is clear that this 10 kb region of nodDNA carries the genes that determine host range and that relatively few bacterial genes may be involved in nodule and bacteroid development.

During analysis of early events in the infection and nodulation of Vicia hirsuta roots inoculated with normal and mutant strains of Rhizobium leguminosarum and strains containing cloned nodulation (nod) genes, a number of novel observations were made. (i) Alternating zones of curled and straight root hairs were seen on roots of V. hirsuta inoculated with the wild-type strain of R. leguminosarum. This phasing of root hair curling was not seen if plants were grown under continuous light or continuous dark conditions. (ii) Reduced nodulation and delayed nodule initiation was observed with a strain carrying a Tn5 mutation in the nodE gene. In addition the phased root hair curling was absent, and root hair curling was observed along the length of the root. (iii) The nodABC genes cloned on a multicopy plasmid in a wild-type strain inhibited nodulation but induced a continuous root hair curling response. Those few nodules that eventually formed were found to contain bacteria which had lost the plasmid carrying the nodABC genes. (iv) With a strain of Rhizobium cured of its indigenous symbiotic plasmid, but containing the cloned nodABCDEF genes, continuous root hair curling on V. hirsuta was observed. However, no infection threads were observed, and surprisingly, it did appear that initial stages of nodule development occurred. Observations of thin sections of these early developing nodules indicated that early nodule meristematic divisions may have occurred but that no bacteria were found within the nodules and no infection threads were observed either within the nodule bumps or within any of the root hairs. It was concluded that for normal infections to occur, precise regulation of the nod genes is required and that overexpression of the root hair curling genes inhibits the normal infection process.

SUMMARY This review will examine the early stages of infection of legume roots by strains of Rhizobium that induce nitrogen-fixing nodules. The object is to show that, at least in terms of ultrastructure, the interactions between the plant and the rhizobia occur at the cell surface interface between these organisms. This situation exists at all stages, from the time the bacteria attach to the surface of the root hairs to the time they occur as the nitrogen-fixing form in the cytoplasm of the nodule cells, enclosed by peribacteroid membranes.

Mutant strains of Rhizobium leguminosarum have been isolated in which the transposon Tn5 was inserted into the cloned nodulation genes. The mutant strains were examined for their ability to induce nodules and to induce normal root hair curling on peas. Five distinct classes of nod mutations were identified on the basis of the phenotypes of the various mutant strains, and of the mapped locations of the nod:: Tn5 alleles. Three classes of mutants (I, II and III) were defective in nodulation and two classes (IV and V) were delayed in nodule appearance. Mutations of classes I, II and III types affected root hair curling and a subcloned 6.6 kb fragment of DNA containing this region conferred the ability to induce root hair curling upon a Rhizobium strain deleted of its nod genes. Analysis of protein products formed after in vitro transcription and translation of the plasmid DNA corresponding to the class I, II, III and IV regions indicated that proteins of molecular weights 48,000, 45,000, 36,000 and 34,000 were formed. A comparison of protein products formed by equivalent plasmids carrying nod:: Tn5 alleles indicated that the class I mutations blocked the synthesis of the 45,000 molecular weight peptide and that the two products of molecular weights 36,000 and 34,000 were absent from the class II mutants. It is concluded that at least five nod genes are involved in nodulation and the polypeptide products of some of these genes have been identified.

General requirements of the FM stereo receiver are reviewed with emphasis on high quality stereo performance commensurate with the system capability. In the commercially manufactured receivers described, proper attention has been given to each of these requirements, and the stereo demodulation circuits are integrated within the radio chassis. Two approaches are covered; one, a complete self-contained stereo FM radio, and the other, a novel solution to the conversion problem for existing FM receivers. The latter consists of a ``Multiplexer'' receiver which is not an ``adaptor'' and which requires no connection to the monaural receiver. Circuit details and performance data are included.

There is hardly anything which stands out so prominently to-day in our industrial activities, as the efficiency obtained by the electric driving of machinery. The duty or performance cycle of the motor naturally depends on the controlling apparatus, and the writer, after describing several types of resistance, endeavors to explain the various forms of magnetic control in vogue to-day for both d-c. and a-c. motors, hoping to bring out a full discussion on the merits of each, also regarding the characteristics embodied in contactor or magnetic switch design.

(1939). Observations on the Life-History and Control of White Borer of Coffee in Kenya. The East African Agricultural Journal: Vol. 5, No. 1, pp. 61-67.

Results from the aeroshell-mounted neutral mass spectrometer on Viking I indicate that the upper atmosphere of Mars is composed mainly of CO(2) with trace quantities of N(2), Ar, O, O(2), and CO. The mixing ratios by volume relative to CO(2) for N(2), Ar, and O(2) are about 0.06, 0.015, and 0.003, respectively, at an altitude near 135 kilometers. Molecular oxygen (O(2)(+)) is a major component of the ionosphere according to results from the retarding potential analyzer. The atmosphere between 140 and 200 kilometers has an average temperature of about 180 degrees +/- 20 degrees K. Atmospheric pressure at the landing site for Viking 1 was 7.3 millibars at an air temperature of 241 degrees K. The descent data are consistent with the view that CO(2) should be the major constituent of the lower martian atmosphere.

• We report our experience with 1,000 consecutive abdominal wound closures using continuous monofilament polypropylene (Prolene) sutures. Wound dehiscence occurred in four patients (0.4%), and incisional hernia occurred in seven patients (0.7%). The incidence of persistent suture sinus was less than 1%. A comparison of these results with the reported data showed that this method was at least equal to other types of wound closure. While the polypropylene suture is more difficult to handle than traditional sutures, it is probably the preferred suture for contaminated and dirty wounds. It has eliminated the need for retention sutures in our practice, and its use as a continuous, running closure has offered the advantage over the usual interrupted technique of being simpler, faster, and more cost effective. Sepsis has continued to be the greatest cause of failure of abdominal wounds to heal. (Arch Surg1983;118:1305-1308)

This paper describes our current understanding of the organization of the nodulation genes in a strain of R. leguminosarum, the species that nodulates peas, Vicia, Lens and Lanthyrus. In many of the fast-growing species of Rhizobium it is well established that the genes for nodulation and nitrogen fixation are clustered on large “symbiotic” plasmids one of which is the R. leguminosarum plasmid pRL 1JI whose transfer to other species of Rhizobium allows the transconjugants to nodulate peas (Johnston et al., 1978). Further, a region, no more than 10kb in size, was sufficient to confer the ability to nodulate peas when transferred to a strain of R. phaseoli cured of its resident symbiotic plasmid (Downie et al., 1983). The fact that the nodulation and host-range genes of pRL1JI are clustered within such a small region means that they can be analysed in considerable detail using both genetical and physical techniques.

The technique using the EEA stapler for low anterior resection of the rectum has been modified to permit a low anastomosis that can be done with greater facility and safety. The method eliminates the bulky puckering of the ampullary purse string and avoids the disadvantage of joining segments of bowel of different sizes. It also decreases intraoperative contamination and minimizes chances for sepsis. Additionally, it affords an opportunity to check the integrity of the anastomosis. Success of the method seems to document the safety of stapling across a staple line. Results of this method used in a small group of patients are encouraging.

Eighteen patients seen between 1974 and 1982 with the clinical diagnosis of inflammatory breast carcinoma underwent modified radical mastectomy after preoperative chemotherapy and radiation therapy. In 17 of the 18 patients (94%), residual carcinoma was detected in either the resected breast or the axillary nodes. All mastectomies were accomplished without major technical difficulty. Seven wound complications, including three infections, occurred. Local recurrence was noted in 29% (five of 17 patients) and distant metastasis was detected in 89% (16 of 18 patients). Only three patients are presently alive without evidence of disease 19, 21, and 21 months since the onset of symptoms. Eleven patients have died, the median survival being 23 months since the development of symptoms, and four are alive with distant metastasis. Modified radical mastectomy can be accomplished in patients with inflammatory breast cancer after preoperative chemotherapy and radiation therapy and may have a role in reducing local tumor burden.

Considerable morbidity and mortality are associated with infections of vascular prosthetic grafts. Most vascular surgeons believe that once vascular prosthetic graft infections occur, any form of therapy short of removal of the prosthesis will fail. Although recent reports have noted the successful conservative treatment of vascular prosthetic graft infections in the groin, most surgeons have been hesitant to use such therapy for aortic prosthetic graft infections. We describe an 88-year-old woman with an aortic graft infection 2 months after abdominal aortic aneurysmectomy who was treated successfully with local debridement and continuous irrigation of the graft bed with providone-iodine solution. Such local therapy is an alternative and sometimes effective method of managing patients with infected aortic grafts in whom the risk of resection of the prosthesis and revascularization would be prohibitive.

The region of the Rhizobium leguminosarum plasmid pRL1JI involved in nodulation and nitrogen fixation has been cloned on a series of four overlapping cosmid clones. These clones represent ˜60 kb of pRL1JI DNA on which a series of Tn5-induced fix and nod alleles have been identified, with the two most distant alleles being separated by ˜45 kb of DNA. The mutant alleles fell into three groups, two clusters of fix alleles separated by one cluster of nod alleles. Within one group of fix alleles, DNA homologous to the nifA gene of Klebsiella pneumoniae has been identified, whereas the pRL1JI DNA homologous to the K. pneumoniae nitrogenase genes is present within the other group of fix alleles.