Generation of transformable spheroplasts from mycelia, macroconidia, microconidia and germinating ascospores of Neurospora crassa

For Neurospora to be generally useful in molecular studies it would be desirable to be able to prepare transformable spheroplasts from mycelia and any of the three types of spores produced by this organism. Transformable spheroplasts are currently prepared from germinating macroconidia by digestion with Novozym 234 in the presence of 1.0 M sorbitol (Vollmer and Yanofsky 1986. PNAS 83:4869-4873). This method is efficient, but requires a 3-5 hr germination step. Elimination of the germination step would be a technical advance. In addition, the standard method is usable only with strains that form large numbers of macroconidia. Thus, interesting mutants that are incapable of forming macro- conidia cannot be used as recipients in cloning experiments. A procedure for generating spheroplasts from mycelia of N. crassa has been reported (Buxton and Radford 1984. MGG 196:339-344). While large numbers of spheroplasts are released by this procedure, the frequency of transformation is low, and we have experienced difficulty obtaining repeatable results. Since we want to clone genes implicated in the macroconidiation process, we devised a procedure that improves the efficiency of transformation of mycelial spheroplasts. As an alternative approach, we developed an transformation protocol for microconidia. Since aconidial mutations can be introduced into a microcycle microconidiating background such as mcm (Maheshwari 1991. Exp. Mycol. 15:346-350), transformation of microconidia represents a viable option for the cloning of conidiation genes. A procedure for generating competent spheroplasts from germinating ascospores also was developed and provides an additional strategy for cloning conidiation genes

Does rotation of B stars depend on metallicity? preliminary results from GIRAFFE spectra

We show the vsini distribution of main sequence B stars in sites of various metallicities, in the absolute magnitude range -3.34 < Mv < -2.17. These include Galactic stars in the field measured by Abt et al. (2002), members of the h & chi Per open clusters measured by North et al. (2004), and five fields in the SMC and LMC measured at ESO Paranal with the FLAMES-GIRAFFE spectrograph, within the Geneva-Lausanne guaranteed time. Following the suggestion by Maeder et al. (1999), we do find a higher rate of rapid rotators in the Magellanic Clouds than in the Galaxy, but the vsini distribution is the same in the LMC and in the SMC in spite of their very different metallicities.Comment: 2 pages, 1 figure, poster presented at the ESO/Arcetri Workshop on "Chemical abundances and mixing in stars in the Milky Way and its satellites", 13-17 Sept. 200

Charm and Beauty in Particle Physics

The spectra of states containing charmed and beauty quarks, and their regularities, are reviewed.Comment: 29 pages, LaTeX, 10 EPSF figures submitted separately. Presented at CERN in September, 1994 at a symposium in honor of Andre Martin To be submitted to Comments on Nuclear and Particle Physic

The Herschel view of the nebula around the luminous blue variable star AG Carinae

Far-infrared Herschel PACS imaging and spectroscopic observations of the nebula around the luminous blue variable (LBV) star AG Car have been obtained along with optical imaging in the Halpha+[NII] filter. In the infrared light, the nebula appears as a clumpy ring shell that extends up to 1.2 pc with an inner radius of 0.4 pc. It coincides with the Halpha nebula, but extends further out. Dust modeling of the nebula was performed and indicates the presence of large grains. The dust mass is estimated to be ~ 0.2 Msun. The infrared spectrum of the nebula consists of forbidden emission lines over a dust continuum. Apart from ionized gas, these lines also indicate the existence of neutral gas in a photodissociation region that surrounds the ionized region. The abundance ratios point towards enrichment by processed material. The total mass of the nebula ejected from the central star amounts to ~ 15 Msun, assuming a dust-to-gas ratio typical of LBVs. The abundances and the mass-loss rate were used to constrain the evolutionary path of the central star and the epoch at which the nebula was ejected, with the help of available evolutionary models. This suggests an ejection during a cool LBV phase for a star of ~ 55 Msun with little rotation.Comment: accepted for publication in A&

Making On-Demand Routing Efficient with Route-Request Aggregation

In theory, on-demand routing is very attractive for mobile ad hoc networks (MANET), because it induces signaling only for those destinations for which there is data traffic. However, in practice, the signaling overhead of existing on-demand routing protocols becomes excessive as the rate of topology changes increases due to mobility or other causes. We introduce the first on-demand routing approach that eliminates the main limitation of on-demand routing by aggregating route requests (RREQ) for the same destinations. The approach can be applied to any existing on-demand routing protocol, and we introduce the Ad-hoc Demand-Aggregated Routing with Adaptation (ADARA) as an example of how RREQ aggregation can be used. ADARA is compared to AODV and OLSR using discrete-event simulations, and the results show that aggregating RREQs can make on-demand routing more efficient than existing proactive or on-demand routing protocols

A Protocol Guide for the N. crassa Yeast Artificial Chromosome Library

A yeast artificial chromosome (YAC) library of Neurospora crassa strain 74-OR23-1A has been constructed. This library has been used to clone 750 kb of contiguous DNA sequences from the centromere region of linkage group VII (M. Centola and J. Carbon. 1994. Mol. Cell. Biol. 14:1510-1519). The purpose of this article is explicitly to outline procedures that have been developed for library screening and chromosome walking

Rotating hyperdeformed quasi-molecular states formed in capture of light nuclei and in collision of very heavy ions

International audienceWithin a rotational liquid drop model including the nuclear proximity energy the l-dependent potential barriers governing the capture reactions of light nuclei and of very heavy ions have been determined. Rotating quasi-molecular hyperdeformed states appear at high angular momenta. The energy range of these very deformed high spin states is given for light systems. The same approach explains the observation of ternary cluster decay from56Ni and 60Zn through hyperdeformed shapes at angular momenta around 45 . The apparently observed superheavy nuclear systems in the U+Ni and U+Ge reactions at high excitation energy might correspond to these rotating isomeric states formed at very high angular momenta even though the shell effects vanish

Potential impacts of climate change on habitat suitability for the Queensland fruit fly

Anthropogenic climate change is a major factor driving shifts in the distributions of pests and invasive species. The Queensland fruit fly, Bactrocera tryoni Froggatt (Qfly), is the most economically damaging insect pest of Australia's horticultural industry, and its management is a key priority for plant protection and biosecurity. Identifying the extent to which climate change may alter the distribution of suitable habitat for Qfly is important for the development and continuation of effective monitoring programs, phytosanitary measures, and management strategies. We used Maxent, a species distribution model, to map suitable habitat for Qfly under current climate, and six climate scenarios for 2030, 2050 and 2070. Our results highlight that south-western Australia, northern regions of the Northern Territory, eastern Queensland, and much of south-eastern Australia are currently suitable for Qfly. This includes southern Victoria and eastern Tasmania, which are currently free of breeding populations. There is substantial agreement across future climate scenarios that most areas currently suitable will remain so until at least 2070. Our projections provide an initial estimate of the potential exposure of Australia's horticultural industry to Qfly as climate changes, highlighting the need for long-term vigilance across southern Australia to prevent further range expansion of this species

Pauli problem for a spin of arbitrary length: A simple method to determine its wave function

The problem of determining a pure state vector from measurements is investigated for a quantum spin of arbitrary length. Generically, only a finite number of wave functions is compatible with the intensities of the spin components in two different spatial directions, measured by a Stern-Gerlach apparatus. The remaining ambiguity can be resolved by one additional well-defined measurement. This method combines efficiency with simplicity: only a small number of quantities have to be measured and the experimental setup is elementary. Other approaches to determine state vectors from measurements, also known as the ‘‘Pauli problem,’’ are reviewed for both spin and particle systems