1,196 research outputs found
Biology of killer yeasts
Killer yeasts secrete proteinaceous killer toxins lethal to susceptible yeast strains. These toxins have no activity against microorganisms other than yeasts, and the killer strains are insensitive to their own toxins. Killer toxins differ between species or strains, showing diverse characteristics in terms of structuralgenes, molecular size, mature structure and immunity. The mechanisms of recognizing and killing sensitive cells differ for each toxin. Killer yeasts and their toxins have many potential applications in environmental, medical and industrial biotechnology. They are also suitable to study the mechanisms of protein processing and secretion, and toxin interaction with sensitive cells. This review focuses on the biological diversity of the killer toxins described up to now and their potential biotechnological applications
Large Area Crop Inventory Experiment (LACIE). LACIE transition year plan for the direct estimation of wheat from LANDSAT imagery
There are no author-identified significant results in this report
Validity of the N\'{e}el-Arrhenius model for highly anisotropic Co_xFe_{3-x}O_4 nanoparticles
We report a systematic study on the structural and magnetic properties of
Co_{x}Fe_{3-x}O_{4} magnetic nanoparticles with sizes between to nm,
prepared by thermal decomposition of Fe(acac)_{3} and Co(acac)_{2}. The large
magneto-crystalline anisotropy of the synthesized particles resulted in high
blocking temperatures ( K \leqq K for d nm ) and large coercive fields ( kA/m for K).
The smallest particles ( nm) revealed the existence of a magnetically
hard, spin-disordered surface. The thermal dependence of static and dynamic
magnetic properties of the whole series of samples could be explained within
the N\'{e}el-Arrhenius relaxation framework without the need of ad-hoc
corrections, by including the thermal dependence of the magnetocrystalline
anisotropy constant through the empirical Br\"{u}khatov-Kirensky
relation. This approach provided values very similar to the bulk
material from either static or dynamic magnetic measurements, as well as
realistic values for the response times ( s).
Deviations from the bulk anisotropy values found for the smallest particles
could be qualitatively explained based on Zener\'{}s relation between
and M(T)
The Use of Patents to Assess National Innovation Systems: Evidences from Spanish Biotechnology
Spain’s economy recorded a high rate of growth from the mid-1990s onwards. At the same time, the resources allocated to Research and Development (R&D) grew at a much faster pace than in other European Union (EU) countries. Spain’s growth recorded an average rate of 2.93% from the early 1990s to 2004. Over the same period, the average growth in the EU was 0.46%. This circumstance, together with several sound policy decisions implemented between 2004 and 2009, ushered in a “golden age of Spanish biotechnology”. In terms of the national patent licenses
issued by the Spanish Patent and Trademark Office (SPTO) between 2004 and 2009, the number in biotechnology grew from 84 to 151. However, the current economic situation in Spain, along with a series of political decisions taken over the past two or three years to cut spending on R&D, predicts a sharp downturn in the performance of Spanish biotechnology. This scenario makes Spain one of the best places to study the successes and failures of the management of science and allows transfer this experience to the other international regions. We need to analyze
the influence of political decisions as a major factor with a bearing on the quality of science.
Using patents as an indicator of scientific development, this paper analyzes the evolution of the biotechnology sector in Spain and its relationship with scientific policy and the management of R&D
Pattern formation from consistent dynamical closures of uniaxial nematic liquid crystals
Pattern formation in uniaxial polymeric liquid crystals is studied for
different dynamic closure approximations. Using the principles of mesoscopic
non-equilibrium thermodynamics in a mean-field approach, we derive a
Fokker-Planck equation for the single-particle non-homogeneous distribution
function of particle orientations and the evolution equations for the second
and fourth order orientational tensor parameters. Afterwards, two dynamic
closure approximations are discussed, one of them considering the relaxation of
the fourth order orientational parameter and leading to a novel expression for
the free-energy like function in terms of the scalar order parameter.
Considering the evolution equation of the density of the system and values of
the interaction parameter for which isotropic and nematic phases coexist, our
analysis predicts that patterns and traveling waves can be produced in
lyotropic uniaxial nematics even in the absence of external driving.Comment: 34 pages, 7 figure
Nonlinear hydrodynamical evolution of rotating relativistic stars: Numerical methods and code tests
We present numerical hydrodynamical evolutions of rapidly rotating
relativistic stars, using an axisymmetric, nonlinear relativistic hydrodynamics
code. We use four different high-resolution shock-capturing (HRSC)
finite-difference schemes (based on approximate Riemann solvers) and compare
their accuracy in preserving uniformly rotating stationary initial
configurations in long-term evolutions. Among these four schemes, we find that
the third-order PPM scheme is superior in maintaining the initial rotation law
in long-term evolutions, especially near the surface of the star. It is further
shown that HRSC schemes are suitable for the evolution of perturbed neutron
stars and for the accurate identification (via Fourier transforms) of normal
modes of oscillation. This is demonstrated for radial and quadrupolar
pulsations in the nonrotating limit, where we find good agreement with
frequencies obtained with a linear perturbation code. The code can be used for
studying small-amplitude or nonlinear pulsations of differentially rotating
neutron stars, while our present results serve as testbed computations for
three-dimensional general-relativistic evolution codes.Comment: 13 pages, 10 figures, submitted to MNRA
Ear, nose and throat manifestations in pemphigus vulgaris
Pemphigus vulgaris (PV) is an autoimmune disease characterized by mucocutaneous intraepithelial blisters and pathogenic autoantibodies against desmoglein 3. There are two clinical forms: mucosal (MPV) and mucocutaneous (MCPV). The frequency of ear, nose and throat (ENT) involvement in PV is not clearly defined. Only a few isolated individual cases have been reported.
OBJECTIVES: The objective of our study was to determine the incidence of ENT involvement in patients with PV.
PATIENTS: We studied prospectively all 16 patients diagnosed with PV and treated in the Department of Dermatology of the University Clinic of Navarra between 2001 and 2005. They were 10 cases of MPV and six cases of MCPV. All patients were evaluated for ENT manifestations by endoscopic examination.
RESULTS: Of the 16 patients, 13 presented with throat symptoms (81%), 12 pharyngeal (75%) and seven laryngeal symptoms (44%). Fourteen patients (88%) had active PV lesions on endoscopic evaluation (eight patients had active lesions on both pharyngeal and laryngeal mucosa, four had PV lesions only on laryngeal mucosa and two had PV lesions on pharyngeal mucosa). Laryngeal lesions were most commonly present in MPV patients. The frequency of nasal symptoms (38%) was lower than active PV lesions (62%) found on ENT examination. Oral symptoms and oral active PV lesions were the most frequent findings (94%). Only three patients with MCPV showed erosions on the external auditory canal.
CONCLUSIONS: As ENT endoscopy allows more extensive areas of mucosa to be examined than simple visual inspection, we recommend that it be included in the examination of all patients with PV. By obtaining more complete information concerning the extent of the disease, a more accurate diagnosis can be made, better choice of drug and dose may be decided and, ultimately, response to treatment may be improved
First narrow-band search for continuous gravitational waves from known pulsars in advanced detector data
Spinning neutron stars asymmetric with respect to their rotation axis are potential sources of
continuous gravitational waves for ground-based interferometric detectors. In the case of known pulsars a
fully coherent search, based on matched filtering, which uses the position and rotational parameters
obtained from electromagnetic observations, can be carried out. Matched filtering maximizes the signalto-
noise (SNR) ratio, but a large sensitivity loss is expected in case of even a very small mismatch
between the assumed and the true signal parameters. For this reason, narrow-band analysis methods have
been developed, allowing a fully coherent search for gravitational waves from known pulsars over a
fraction of a hertz and several spin-down values. In this paper we describe a narrow-band search of
11 pulsars using data from Advanced LIGO’s first observing run. Although we have found several initial
outliers, further studies show no significant evidence for the presence of a gravitational wave signal.
Finally, we have placed upper limits on the signal strain amplitude lower than the spin-down limit for 5 of
the 11 targets over the bands searched; in the case of J1813-1749 the spin-down limit has been beaten for
the first time. For an additional 3 targets, the median upper limit across the search bands is below the
spin-down limit. This is the most sensitive narrow-band search for continuous gravitational waves carried
out so far
Effects of water potential on spore germination and viability of Fusarium species
Germination of macroconidia and/or microconidia of 24 strains of Fusarium solani, F. chlamydosporum, F. culmorum, F. equiseti, F. verticillioides, F. sambucinum, F. oxysporum and F. proliferatum isolated from fluvial channels and sea beds of the south-eastern coast of Spain, and three control strains (F. oxysporum isolated from affected cultures) was studied in distilled water in response to a range of water potentials adjusted with NaCI. (0, -13.79, -41.79, -70.37, -99.56 and -144.54 bars). The vialibility (UFC/ml) of suspension was also tested in three time periods (0,24 and 48h). Conidia always germinated in distilled water. The pattern of conidial germination obseved of F. verticillioides, F. oxysporum, F. proliferatum, F. chlamydosporum and F. culmorum was similar. A great diminution of spore germination was found in -13.79 bars solutions. Spore germination percentage for F. solani isolates was maximal at 48 h. and -13.79 bars with 21.33% spore germination, 16% higher than germination in distilled water. F. equiseti shows the maximum germination percentage in -144.54 bars solution in 24 h time with 12.36% germination. These results did not agree with those obtained in the viability test where maximum germination was found in distilled water. The viability analysis showed the great capacity of F. verticilloides strains to form viable colonies, even in such extreme conditions as -144,54 bars after 24 h F. proliferatum colony formation was prevented in the range of -70.37 bars. These results show the clear affectation of water potential to conidia germination of Fusaria. The ability of certain species of Fusarium to develop a saprophytic life in the salt water of the Mediterraneam Sea could be certain. Successful germination, even under high salty media conditions, suggests taht Fusarium spp. could have a competitive advantage over other soil fungi in crops irrigated with saline water. In the specific case of F. solani, water potential of -13.79 bars affected germination positively. It could indicate that F. solani has an special physiological mechanism of survival in low water potential environments
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