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Recent numerical studies indicate that the low Earth orbit (LEO) debris environment has reached a point such that even if no further space launches were conducted, the Earth satellite population would remain relatively constant for only the next 50 years or so. Beyond that, the debris population would begin to increase noticeably, due to the production of collisional debris (Liou and Johnson, 2008). Measures to be enforced play thus a major role to preserve an acceptable space mission risk and ensure sustainable space activities. The identification of such measures and the quantification of their efficiency over time for LEO missions is of prime concern in the decision-making process, as it has been investigated for the last few decades by the Inter-Agency Space Debris Coordination Committee (IADC). This paper addresses the final results of a generic methodology and the characteristics of a tool developed to assess the efficiency of the risk reduction measures identified for the Sentinel-1 (Si) mission. This work is performed as part of the 34-month P-2-ROTECT project (Prediction, Protection & Reduction of OrbiTal Exposure to Collision Threats), funded by the European Union within the Seventh Framework Programme. Three ways of risk reduction have been investigated, both in short and long-term, namely: better satellite protection, better conjunction prediction, and cleaner environment. According to our assumptions, the Si mission vulnerability evaluations in the long term (from 2093 to 2100) show that full compliance to the mitigation measures leads to a situation twice safer than that induced by an active debris removal of 5 objects per year in a MASTER(2009) Business-As-Usual context. Because these measures have visible risk reduction effects in the long term, complementary measures with short response time are also studied. In the short term (from 2013 to 2020), a better prediction of the conjunctions is more efficient than protecting the satellite Si itself. By combining a better prediction with an enhanced satellite protection the Si is estimated to extend its extra mission lifetime by 4% with respect to its nominal lifetime (7.25 years).

CRYSIS is an electron beam ion source (EBIS) with a superconducting solenoid. Highly charged ions are delivered to the acceleration and storage ring CRYRING [ K. Abrahamsson et al., Nucl. Instr. Methods B 79 (1993) 269.], SMILETRAP [C. Carlberg et al., Phys. Scr. T 59 (1995) 196.] and to low energy atomic and surface physics experiments. Stable electron beam currents up to 700 mA are obtained, in order to enhance the ion yield out of the EBIS. Measurements of the total charge per pulse at different working conditions and electron beam current density measurements were done. At electron beam currents of 600 mA yields up to 2.5 × 1010 charges per pulse could be measured.

Emissivity extraction from hyperspectral infrared data is a challenge as it is a under-determined problem, and particularly with noisy data. A new method for emissivity retrieval dedicated to hyperspectral data that cover infrared as well as reflective spectral domains has been developed to overcome difficulties related to noise. The method is derived from the EARTH (surface Emissivity, temperature and Atmosphere Retrievals from Thermal infrared Hyperspectral image) algorithm [1], but takes advantage of the abundance of spectral information in the reflective domain, by including a classification step in the emissivity retrieval process. The attributes considered in this step are the first principal components of the reflective image (in radiance or reflectance units) that contain rich spectral information, and the brightness temperatures computed on the infrared image after spectral binning that give information on surface temperature. A k-means classification is carried out. Infrared spectral radiances are then averaged in each class and atmospheric compensation, based on neural networks followed by surface temperature / emissivity separation (TES), based on spectral smoothness is achieved. The benefits of the classification step are demonstrated on AHS data. Then the method is applied on simulated noisy data. The accuracy on emissivity is clearly improved when compared to results obtained without classification step.

CRYRING is a small synchrotron and storage ring equipped with electron cooling. Highly charged ions from the electron beam ion source CRYSIS or singly charged ions from the plasmatron source MINIS are injected via an RFQ into the ring. The facility is in the commissioning phase. Full design energy has been achieved and electron cooling demonstrated both for atomic and molecular ions. The experimental program started in August with two projects, dissociative recombination of H+3 ions and radiative recombination to deuterons. The status as of September 20, 1992, is reported.

An electron string is a state of a one component electron plasma, which can arise when multiply reflected electrons are accumulated in a strong solenoidal magnetic field. Based on the electron beam ion source (EBIS) in the reflex mode of operation the processes of the string formation and its decay were observed and the characteristic times of the processes have been measured. Information about the electron energy distribution in electron strings has been obtained using four independent methods. It was shown, the distribution is broad and, moreover, there is some amount of electrons, having energies higher than the energy of the electrons used for feeding the string. An instability was observed as a starting point of electron string formation. The instability is strongly suppressed and the string is formed when the injecting electron current reaches a threshold value, which depends on a quality of electron focusing. Most likely the instability observed is responsible for the string electron energy spread....

A reflective actor language that is used as a development tool for implementing distributed artificial intelligence systems is described. The MERING IV language is bound on the actor model of computation, which allows for autonomy and concurrency. MERING IV is a reflective language, i.e., a language that can represent itself, both structurally and operationally. MERING IV implements a model of reflection called compilation-based reflection. Reflection in MERING IV is used as a glueing mechanism that permits agents of various sizes and intelligences to communicate in a uniform manner. An example of the use of reflection for describing transparent protocols between agents is given. >

An optimized synthesis method for the design of multiport branch-waveguide couplers with arbitrary output power distributions is presented. This component offers the potential to reduce the complexity, mass, and size of beam-forming networks of multiple or contoured satellite antennas. The proposed technique has been successfully used to design and manufacture a six-port five-branch coupler in the WR75 waveguide with a 10.95-12.75 GHz bandwidth. The measured results agree well with the computed frequency response. It is noted that the device discussed is also suitable for multimode antenna applications. >

The experimental program at CRYRING storage ring began shortly after the installation of the electron cooler in May 1992. The performance of the ion sources and the ring is reported. Results of electron cooling are reviewed and a method to improve the efficiency of electron cooling is presented. >

An optimized design method for eight-port branch-waveguide directional couplers with arbitrary output power distribution is presented. This component is suitable for beam forming network (BFN) applications. In fact the proposed device yields a more compact design of BFNs. An eight-port coupler prototype in the WR75 waveguide has been manufactured. Comparing scattering parameter measurements with the coupled frequency performance shows that the design procedure is verified very satisfactorily. Moreover these couplers can be used as multiport power dividers with four input and four output ports. An example of a 4-way power divider suitable for multiport amplifier applications is presented. >

Using the OSIRIS on-line isotope separator facility, the decays of 130Sn and 130, 132Sb have been studied. On the basis of singles γ and γ-γ coincidence Ge(Li) spectra and conversion electron Si(Li) measurements, level schemes for 130Sb, 130Te and 132Te have been constructed. The corresponding half-lives have been measured using multiscaling technique. The 3.8 min ground state of 130Sn populates only positive parity states in the πν−3 nucleus 130Sb: the energetically lowest 5+ state with the (π1 g 7 2 , ν2 d 3 2 ) configuration assignment; the T 1 2 = 3.6 ± 0.3 ns 4 + state at 70.0 keV; the 2+ state at 262.5 keV; the (0, 1)+ state at 697.2 keV; the 3+ state at 813.1 keV and the 1+ state at 1042.3 keV excitation energy. A 1.7 min isomeric state in 130Sn, with the tentative spin assignment (7−), populates several odd parity levels in 130Sb. These arise from the (π1 g 7 2 , ν1 h 11 2 -1 ) and/or (π2 d 5 2 , ν1 h 11 2 -1 ) configurations and are located 84.7 keV (6−), 144.9 keV (7−), 688.5 keV and 1044.0 keV above the 40 min 8− β- decaying state. No transitions between odd and even parity states have been observed. The most important excited states in 130Te found in the β− decay of the 6.6 min 130Sb 5+ state are: 839.4 keV, 2+; 1632.8 keV, 4+; 1815.1 keV, 6+; 2100.8 keV, 5−. Levels in the π2ν−2 nucleus 132Te were observed in the β− decays of the 2.8 min 132Sb (4+) and the 4.2 min 132Sb (8−) states. Unique spin and parity assignments have been given to the following states: 973.9 keV, 2+; 1670.7 keV, 4+; 1774.1 keV, 6+; 1924.7 keV, 7−; 2053.0 keV, 5−.

Summary An isometric spiroplasma virus SpV4/B63-G1 from honey-bee spiro-plasma strain B63 of subgroup I-2 was propagated on spiroplasma strain G1 of the same subgroup. Each strain in which SpV4 could be propagated belonged to subgroup I-2; however, SpV4 did not multiply in all strains of this subgroup. The virions were purified by density gradient centrifugation. The infective particle had a density of 1.24 g/cm3 in metrizamide and 1.40 g/cm3 in cesium chloride. SpV4 was insensitive to non-ionic detergents, chloroform and ether. SpV4 virions contained circular single-stranded DNA of 1.7×106 daltons. A 60,000-d polypeptide seemed to be the only capsid protein. Multiplication curves of SpV4 showed that virus production occurred from 2 to 6 h after initial infection. The involvement of a lytic process in virus release is discussed.

Gamma-ray and conversion electron spectra associated with the decay of 40 min 130Sb have been measured with Ge(Li) and Si(Li) detectors. The antimony samples were produced using the on-line isotope separator OSIRIS to isolate the fission products from 235U. On the basis of the measured singles and γ-γ coincidence spectra, a new level scheme has been constructed. The most important states observed are: 839.4 keV, 2+; 1632.8 keV, 4+; 1815.1 keV, 6+; 2100.8 keV, 5−; and 2146.0 keV, 7−. Using delayed coincidence techniques a half-life of 9.8±0.5 ns was deduced for the 6+ state. This implies that the 182.3 keV transition connecting the 6+ and 4+ states has B(E2)exp = 240±12 e2 · fm4. This value is 2.8 times greater than that theoretically predicted if both states are assumed to be pure (g 7 2 )2 two-proton configurations. The T 1 2 . for the 7− state was determined to be 115±8 ns giving a hindrance factor of 1.8 × 107 with respect to the Weisskopf estimate for the 330.9 keV 7− → 6+ El transition. The origins of the 5− and 7− states are ascribed mainly to the ( 1 h 11 2 ), 3 s 1 2 ) and ( 1 h 11 2 , 2 d 3 2 ) two-neutron configurations, respectively.

By studying high-energy β − particles the 0.53±0.05 sec decay of 130 49 In 81 and excited states in the two-neutron-hole nucleus 130 50 Sn 80 have been observed. These states have been given the tentative assignments 2 + (1217 keV), 4 + (1992 keV) and 5 − (2119 keV).

Le parasitisme par Nematodes a ete etudie chez le ScolyteBlastophagus destruens, ravageur des Pins dans le Sud-Est de la France. Des especes deja connues de Nematodes associes a cet Insecte ont ete trouvees:Panagrolaimus tigrodonFuchs, 1930;Macrolaimus canadensisSanwal, 1960;Mikoletzkya sp etBursaphelenchus sp. Une espece nouvelle est decrite:Ruidosaphelenchus janasii. Les stades larvaires deParasitaphelencus papillatusFuchs, 1937 etParasitorhabditis piniperdae (Fuchs, 1937)Ruhm, 1954, vivent dans la cavite generale de l'hote. La variation des taux d'infection et l'action sur l'insecte hote de ces deux Nematodes parasites sont discutees.

The β-decay of the doubly closed 132Sn nucleide and the accompanying γ-rays in the pn−1 nucleus 51132Sb81 were studied using Ge(Li) and anthracene detectors. The tin samples were produced using the OSIRIS on-line isotope separator for fission fragments of 235U. A half-life of 40±1 sec has been determined for the ground state of 132Sn which decays by a single β-transition to a 1+ level at 1324.3 keV in 132Sb. This level is de-excited by γ-transitions of different energies. The first excited state (3+) of 132Sb occurs at 85.5 keV. Using a delayed-coincidence technique with fast timing, the half-life of this 3+ state has been measured to be T 1 2 = 14.8±1.8 ns . The B(M1) value associated with this transition to the 4+ ground state is compared with the calculated transition probability. The states observed in 132Sb are interpreted in terms of different pn−1 configurations and calculations have been made using a δ-force interaction between the odd proton and the odd-neutron hole. The reduced transition probability for the 40 sec β-decay of 132Sn is compared with the calculated B(GT) value.

Two spiroplasma strains (B31 and B39) recovered from diseased honey-bees (Apis mellifera) in southwestern France were similar in biochemical, serological and pathological properties. The organisms grew at 30 degrees C, required cholesterol for growth, fermented glucose, catabolized arginine and produced a film and spot reaction. The two spiroplasmas were serologically indistinguishable but were related to serogroup IV spiroplasmas, which had been previously isolated from flower surfaces and from insects. The isolates were distinct from the three previously established species of Spiroplasma and from other presently known serogroups. The G + C content of the DNA from strain B31 was 30 +/- 1 mol %. Both B31 and B39 strains were associated with a lethal infection ("May disease") of the honey-bee. On the basis of the characterization presented here, it is proposed that these spiroplasmal pathogens of bees and allied strains be classified as a new species, Spiroplasma apis, the type strain of which is B31 (ATCC 33834).

To study natural transmission of Spiroplasma citri in the Mediterranean area, periwinkles (Vinca rosea L.) were exposed to natural infection in several locations during the summer of 1983. Detection of S. citri in the periwinkles was assayed by ELISA and culture of the organisms. Some of the periwinkles developed yellows disease symptoms; they contained helical organisms in their sieve tubes, as determined by electron microscopy. A spiroplasma could be cultured from them, but their ELISA reaction for S. citri detection was negative. These results suggested that a spiroplasma different from S. citri had been discovered. The apparently new spiroplasma (P40) was examined for serological relationships with other spiroplasmas by metabolism inhibition and deformation tests. Spiroplasma P40 was found to have relatedness only to Group I spiroplasmas. Healthy periwinkles graft inoculated with shoots of the initial symptomatic periwinkle showed yellows symptoms 3 months after inoculation. Extracts of the initial and the graft-inoculated periwinkles gave positive ELISA reactions with anti-P40 IgG.

Spiroplasma virus Group 4 was propagated, purified and characterized. The isometric capsid is made from one major protein of 60,000 Da and contains a circular single-stranded DNA molecule of 1.7 X 10(6) Da. The host-range of SV4 is limited to Subgroup I-2 spiroplasmas. The virions are released from the infected cells by a lytic process. Transfection of spiroplasmas of Subgroup I-2 by the viral DNA was demonstrated. A high efficiency of transfection was routinely obtained in the presence of polyethyleneglycol. These experiments indicate that spiroplasmas can absorb viral DNA, opening the way for cloning.

PPAV is a type of Mollicutes that was isolated in SP4 medium from seeds of apples affected by proliferation, a disease in which mycoplasma-like organisms (MLOs) are involved. However, PPAV is probably not the etiological MLO agent for at least two reasons: 1) optimal temperature growth is 43 C, and 2) in spite of numerous isolation attempts over several years, no second PPAV culture could be obtained. PPAV is surrounded by a single cytoplasmic membrane and forms typical fried egg-shaped colonies on solid medium. The organism grows in simplified mycoplasma media, such as BSR. In growth inhibition, it shows no serological relationships with any other mycoplasmas or acholeplasmas, including those cultured from the surfaces of plants. The absence of relatedness of PPAV to other Mollicutes was confirmed by DNA hybridization studies. The genome of PPAV is close to 10(9) daltons and contains 25.2 mol % G + C. Its genome size is similar to that of Acholeplasma spp. and Spiroplasma spp. It has, however, a clearcut sterol requirement and therefore cannot be an acholeplasma. Neither is it a spiroplasma since, though filamentous in BSR medium, it has never shown signs of helicity. Hence, PPAV is a taxonomical paradox.

Further analysis of three sterol-nonrequiring Mollicutes (strains PS-1, TAC, and YJS) isolated from gut fluids of insects confirms their similarity to Acholeplasma. They are serologically distinct from acholeplasmas of vertebrates and several other sterol nonrequiring Mollicutes isolated from plant surfaces. The PS-1 strain had a DNA G + C content of 31 mol % and a genome size of 1,030 megadaltons (MDa). Optimum temperature is in the range of 23 to 30 C. Thirty-two new nonhelical Mollicutes isolated from a much wider range of insect hosts were examined for acholeplasmas. Twenty-five of the insect isolates were grown consistently in serum-free broth, with or without Tween 80 supplements. Two of the acholeplasmas were serologically related to Acholeplasma florum, 13 strains were serologically identical to the TAC isolate reported earlier, and 10 of the putative acholeplasmas could not be identified with current reference antisera. Seven of the new nonhelical insect isolates appeared to be sterol-requiring Mollicutes. One sterol-requiring isolate (ELCN-1) was recovered from the hemolymph of a firefly, and is the first report of nonhelical Mollicutes in the insect hemocoel. Two of the seven sterol-requiring Mollicutes, which were nonhelical in earlier passages in broth, later reverted to typically helical spiroplasmas. Confirmation of sterol-requiring, nonhelical Mollicutes in insects would provide an important ecological finding that insects constitute an important reservoir for both acholeplasmas and mycoplasmas.