1,951 research outputs found
Crystal Structure and Al/Si Cation Ordering in Fassaite : A Combined Single Crystal, 27Al and 29Si NMR Study
Al-,Ti-rich diopside, referred to herein as fassaite, occurs in both terrestrial and extraterrestrial environments. The composition of fassaite, Ca(Mg,Al)(Si,Al)2O6, makes it ideal for Al/Si cation ordering studies. In this study, crystal XRD, 27Al and 29Si MAS NMR as well as 27Al 3QMAS NMR is used to study cation ordering in extraterrestrial fassaite from Allende CAIs and a terrestrial analogue from Fassa Valley Italy. From 27Al and 29Si spectroscopy, fassaite from Allende CAIs is found to have more local Al/Si cation ordering than terrestrial Fassaite. Both terrestrial and extraterrestrial have C2/c symmetry indicating long range cation disorder. Completely ordered fassaite has never been found in nature. The local ordering in the Allende fassaite likely indicates ordering above the disorder/ order transition temperature. Cation ordering could provide an independent estimate of temperature and cooling rate on the Allende parent body, once the transformation temperature is known
Application of chicken microarrays for gene expression analysis in other avian species
BACKGROUND: With the threat of emerging infectious diseases such as avian influenza, whose natural hosts are thought to be a variety of wild water birds including duck, we are armed with very few genomic resources to investigate large scale immunological gene expression studies in avian species. Multiple options exist for conducting large gene expression studies in chickens and in this study we explore the feasibility of using one of these tools to investigate gene expression in other avian species. RESULTS: In this study we utilised a whole genome long oligonucleotide chicken microarray to assess the utility of cross species hybridisation (CSH). We successfully hybridised a number of different avian species to this array, obtaining reliable signals. We were able to distinguish ducks that were infected with avian influenza from uninfected ducks using this microarray platform. In addition, we were able to detect known chicken immunological genes in all of the hybridised avian species. CONCLUSION: Cross species hybridisation using long oligonucleotide microarrays is a powerful tool to study the immune response in avian species with little available genomic information. The present study validated the use of the whole genome long oligonucleotide chicken microarray to investigate gene expression in a range of avian species
Sustainable organic plant breeding: Final report - a vision, choices, consequences and steps
In general, the characteristics of organic varieties - and by extension of organic plant breeding - differ from that of conventional breeding systems and conventional varieties. Realising an organic plant breeding system and subsequently steering it to meet changing demands is no less than a mammoth task. The many actions to be undertaken can be divided into short-term commercial and scientific activities, and longer or long-term commercial and scientific activities.
Action must be taken in the short-term to ensure adequate quantities of organically propagated plants and seed. This is vital in consideration of Regulation 2092/91/EC which states that, as of 1 January 2000, all propagating material used in organic production must be of organic origin.
Additional measures are needed to accelerate the development of organically propagated varieties. Within the breeding sector, variety groups should be established to streamline communication in the chain. Variety groups should have a large contingent of farmers, as well as representatives from the trade branch and breeders. Members should communicate intensively with each other, share experiences, and participate in trials and variety assessments. Questions, wishes and bottlenecks could be recorded by variety groups and passed on to other parties in the chain.
The practical details of the plant health concept which is at the basis of organic breeding must be worked out (operationalised). This will require scientific research, for example on:
root development and mineral absorption efficiency
weed suppressive capacity
in situ versus ex situ maintenance
resistance breeding in combination with cultivation measures
seed-transmitted diseases
adaptive capacity
alternatives for growth stimulants, silver nitrate and silver thiosulfate in the cultivation of cucumbers and pickles
Such research should be carried out by academic institutions (such as Wageningen University and Research Centre) in collaboration with Louis Bolk Institute, Stichting Zaadgoed and private companies. A platform should be established to make an inventory of problems and priorities and to develop research proposals. Farmers could contribute their ideas to the platform through the variety groups.
Conclusion
A plant breeding system for organic production should be based on the organic concept of plant health and on the organic position on chain relationships. As the total land area under organic production is still relatively small, it is unlikely that commercial breeders will make large investments to develop organic breeding programmes without financial support from other parties, i.e. the government. In this early stage, it is vital that the government provides generous funding and plays an active enabling role. We hope that the action plan to stimulate organic plant breeding, as requested by Parliament, will dovetail with the activities described above
VLT Diffraction Limited Imaging and Spectroscopy in the NIR: Weighing the black hole in Centaurus A with NACO
We present high spatial resolution near-infrared spectra and images of the
nucleus of Centaurus A (NGC 5128) obtained with NAOS-CONICA at the VLT. The
adaptive optics corrected data have a spatial resolution of 0.06" (FWHM) in K-
and 0.11" in H-band, four times higher than previous studies. The observed gas
motions suggest a kinematically hot disk which is orbiting a central object and
is oriented nearly perpendicular to the nuclear jet. We model the central
rotation and velocity dispersion curves of the [FeII] gas orbiting in the
combined potential of the stellar mass and the (dominant) black hole. Our
physically most plausible model, a dynamically hot and geometrically thin gas
disk, yields a black hole mass of M_bh = (6.1 +0.6/-0.8) 10^7 M_sun. As the
physical state of the gas is not well understood, we also consider two limiting
cases: first a cold disk model, which completely neglects the velocity
dispersion; it yields an M_bh estimate that is almost two times lower. The
other extreme case is to model a spherical gas distribution in hydrostatic
equilibrium through Jeans equation. Compared to the hot disk model the best-fit
black hole mass increases by a factor of 1.5. This wide mass range spanned by
the limiting cases shows how important the gas physics is even for high
resolution data. Our overall best-fitting black hole mass is a factor of 2-4
lower than previous measurements. With our revised M_bh estimate, Cen A's
offset from the M_bh-sigma relation is significantly reduced; it falls above
this relation by a factor of ~2, which is close to the intrinsic scatter of
this relation. (Abridged)Comment: 12 pages, 14 figures, including minor changes following the referee
report; accepted for publication in The Astrophysical Journa
Recommended from our members
Report for General Research January 8, to April 30, 1951 (Alpha - Neutron Volume)
An experimental, gamma-sensitive, coaxial radioelectric cell has been tested by the Control Section. It was found to be as precise as the rotating sample gamma counter but much faster and simpler to operate. A gamma-sensitive, radioelectric cell of improved design has been constructed for the 'Y' Section. A neutron sensitive radioelectric cell has been tested over a range of pressures with various filling gases and with several combinations of hydrogenous electrode backings. Neutron to gamma discrimination ratios as high as 2,000 to 1 were obtained, A multiple electrode, alpha radiation, radioelectric cell using coated plastic electrodes gave increased current output, but the electrode life was quite short. Preliminary life tests indicated that aluminum electroscope foil would give excellent electrode life and techniques were worked out for making good electrodes of both aluminum and of gold electroscope foil. The vacuum-pressure gas system has been redesigned and completely rebuilt (p. 5) The fast-neutron scintillation counter is much smaller and lighter than a B-wall proportional counter and a large moderator. The former is more efficient for polonium-beryllium neutron sources but is less efficient for radium-beryllium neutron sources or for polonium sources producing lower energy neutrons The fast neutron scintillation counter would thus be very useful if the neutron to gamma discrimination ratio could be markedly improved. Preliminary experiments indicate that this ratio can be improved by carefully tailoring the frequency response characteristics of the amplifier used. Phosphors are also being investigated from the standpoint of improving this ratio. Preliminary attempts to detect neutrons by measuring the neutron-capture gamma of cadmium were unsuccessful. However, the conversion gamma from alpha-beryllium neutron sources can be detected with high efficiency; and this might be used to determine the neutron flux from such sources even in the presence of high backgrounds of lower energy gammas (p. 8). Maximum efficiency is obtained for polonium-beryllium neutron sources when the beryllium powder contains a minimum of oxide, when the polonium is 'shot' into the source container and when the curie-to gram-of-beryllium ratio is in the range of 5 to 11 (p. 11). Four mock-fission neutron sources have been prepared in an attempt to improve the efficiency which can be obtained by the evaporation technique (p. 13). A polonium-boron neutron source of unusually high efficiency has been made by the evaporative procedure. Two further attempts to prepare polonium-boron neutron sources by volatilization gave low efficiency (p. 14). Polonium, satisfactory for making neutron sources, has been reclaimed from large volumes of hydrochloric acid containing high concentrations of contaminating ions (p. 15). Work has continued on the problem of determining the total energy emitted from a covered alpha source. The effective thickness of a tantalum hold-down apparently, increases with time. If a source does not contaminate acetone after 24 hours immersion, it can be considered as being satisfactorily sealed. It is believed that a satisfactory seal of a tantalum hold-down to a gold plated source can be obtained by using a gold foil ring between the hold-down and the source, clamping to give pressure, and heating in a vacuum (P. 16)
PERBENIHAN KULTUR JARINGAN ANGGREK PADA TEACHING INDUSTRY UNIVERSITAS HASANUDDIN
Kegiatan PPMU-PPUPIK Perbenihan Kultur Jaringan Anggrek pada Teaching Industry Universitas Hasanuddin (UNHAS) bertujuan untuk mempercepat proses pengembangan budaya kewirausahaan, mendorong berkembangnya budaya pemanfaatan hasil riset UNHAS bagi masyarakat, dan menunjang otonomi kampus melalui perolehan pendapatan mandiri atau bermitra. Dalam pencapaian tujuan jangka panjangnya, kegiatan ini dalam jangka pendek bertujuan untuk memberikan kesempatan dan pengalaman kerja kepada mahasiswa, dan membantu menciptakan akses bagi terciptanya wirausaha baru. Untuk mencapai tujuan tersebut dilakukan kegiatan perbanyakan semaian biji dan bibit anggrek spesies/hibrida di laboratorium, dan pelatihan tentang teknik kultur jaringan skala rumah tangga dimana diajarkan tentang penyederhanaan teknik kultur jaringan tanaman sehingga dapat dilakukan pada skala rumah tangga. Kegiatan laboratorium dan pelatihan dilaksanakan di Teaching Industry UNHAS dan bermitra dengan pengusaha tanaman hias lokal yang berada di Makassar yang memiliki kebun anggrek di Bulu Dua, Kabupaten Barru. Produksi (production planning) yang dilakukan adalah semaian bibit botol/semai biji anggrek disubkultur dan dilakukan pemeliharaan sampai menjadi dewasa dan siap untuk aklimatisasi. Kemudian planlet yang telah diaklimatisasi dirawat dan dipelihara di screen house sampai menjadi anggrek dewasa yang siap jual ke pasaran. Selain itu planlet yang diperbanyak di laboratorium juga telah dipasarkan. Hasil penjualan anggrek yang paling digemari konsumen adalah Seedling Dendrobium dan Phalaenopsis Hibrida serta anggrek Macodes. Pelatihan kultur jaringan sederhana dilakukan dengan pengenalan budidaya anggrek dan teknik kultur jaringan sederhana, perakitan alat kultur jaringan sederhana, praktek teknik kultur jaringan dimulai dari pembuatan media, penanaman, sampai pada aklimatisasi. Dari hasil pelatihan yang dilaksanakan dapat disimpukan bahwa kultur jaringan tidak mahal dan rumit, serta dapat disederhanakan dengan teknik-teknik yang mudah dipahami peserta.Kata kunci: anggrek, kultur jaringan sederhana, pelatihan, perbeniha
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