Optical Resonances in Reflectivity near Crystal Modes with Spatial Dispersion

We study the effect of spatial dispersion of crystal modes on optical properties such as the reflectivity $R$. As an example for isotropic media, we investigate the simplest model for phonons in ionic crystals and compare with previous results for highly anisotropic plasmons, which are now understood from a more general point of view. As a consequence of the wave vector dependence of the dielectric function small changes in the lineshape are predicted. Beyond that, if the frequency of minimal $R$ is near a pole of the dispersionless dielectric function, the relative amplitude of dips in $R$ with normal and anomalous dispersion differ significantly, if dissipation and disorder are low.Comment: 4 pages, 7 eps figures, minor change

Photosynthesis and Degree of Polymerization of Fructan during Reproductive Growth of Meadow Fescue at two Temperatures and two Photon Flux Densities

Accumulation of dry weight was measured in plant parts of meadow fescue (Festuca pratensis Huds.) that was grown at 16/11 °C or 26/21 °C and with 20 or 60 nE cm−2 s−1 photosynthetically active radiation. Plants reached anthesis about 3 weeks later at 16/11 °C than at 26/21 °C and had then a higher proportion of dry weight in inflorescences and less in leaf blades. Growth temperature had little effect on CO2 exchange rate (CER) but plants grown at 60 nE cm−2 s−1 had higher CER than those grown at 20 nE cm−2 s−1. The concentration of water-soluble carbohydrates (WSC) at similar growth stages was usually higher at 16/11°C than at 26/21°C. High radiation also led to higher WSC in stem and leaf tissue. Root tissue changed least and WSC did not exceed 10% of dry weight during the experiment. In all tissues, when WSC was high, the fructans were distributed into a group with a high degree of polymerization (DP) and another with a low DP. The low DP group included sucrose, reducing sugars and fructans up to about 20 units long. An apparent threshold concentration of WSC was necessary for synthesis of the high DP fructans. This concentration was near 12% for leaf tissue, about 6% for stem base tissue, and 2.5% for root tissue. The average apparent DP of the high DP fructan group was 43 to 50 for leaf tissue, 31 to 93 for stem base tissue, and 27 to 31 for roots. These characteristics appeared to be mostly tissue dependent with less effect from temperature and radiatio

Renormalization Group Improved Exponentiation of Soft Gluons in QCD

We extend the methods of Yennie, Frautschi and Suura to QCD for the summation of soft gluon effects in which infrared singularities are cancelled to all orders in $\alpha_s$. An explicit formula for the respective \rngp improved exponentiated cross section is obtained for q+\bbar{{q'}}\to q+\bbar{{q'}}+ n(G) at SSC energies. Possible applications are discussed.Comment: 7 pages (1 figure not included, available on request) LATEX, UTHEP-93-040

Mejora de la germinación de semillas de las especies andaluzas amenazadas: Euollymus latifolius, Buxus sempervirells, Cotolleaster grallatellsis y Rltododelldroll pOllticum subsp. baeticulll

72 páginas.-- 52 figuras.-- 27 tablas.-- referencias.-- Memoria presentada para el XLIII Curso Internacional de Edafología y Biología VegetalDirector: Antonio Troncoso de ArceLa conservación y el desarrollo sostenible de los bosques son temas esenciales dentro de algunas políticas comunes vigentes, como las de desarrollo rural, medio ambiente y otras. Los principios de la utilización sostenible de los bosques se definen y aplican en el marco de programas forestales nacionales, regionales, gobiernos autónomos o mediante otros instrumentos de los estados miembros de la UE. Según la información suministrada por el plan Forestal Español, la superficie forestal, una vez actualizados los datos del inventario Forestal Nacional en su tercera fase (1997-2002), asciende a 26.273.235 hectáreas, equivalentes al 51.93% del territorio español. Aunque este porcentaje es superior al de la mayoría de los países Europeos, a diferencia de estos, una buena parte de la superficie forestal de España carece de árboles ya que tan solo el 56% (14.732.247 hectáreas) de la superficie forestal esta arbolada y se la puede considerar, en consecuencia, como bosque. La Comunidad Autónoma de Andalucía es la segunda en superficie protegida ascendiendo ésta a 4.325.378 hectáreas equivalentes al 16.46% del territorio Español. En ella se encuentran 82 espacios naturales en diferentes escalas de protección, garantizando así la conservación de una buena parte de su flora. Entre ellos se pueden destacar el Parque Natural de Cazorla, Segura y Las Villas, el de Sierra Nevada y, uno de los más extensos, el Parque Natural "Los Alcornocales" con una superficie 170.025 hectáreas cubriendo buena parte del Campo de Gibraltar. En los citados se han recolectado semillas de las especies estudiadas en el presente trabajo.La Agencia Española de Cooperación Internacional (AECI) del Ministerio de Asuntos Exteriores y CooperaciónPeer reviewe

Pengaruh warna lampu light emitting diode dalam air terhadap hasil tangkapan ikan Teri (Stolephorus commersonii) dengan bagan

Lift nets is one of the fishing gear which operate at the night.  This fishing gear are using light as a aids to attract fish into the fishing area.  Research on the use of LED lights in water on lift nets is carried out in Tateli Weru Waters, with the aim to see how the effect of using different color underwater LED lights on anchovy catches (Stolephorus commersonii), and knowing the amount of anchovy (Stolephorus commersonii) catch on lift net using the experimental method, where data is analyzed using Completely Randomized Block Design (RCBD), and continued by Least Significant Difference test (LSD).  Trial of anchovy fishing (Stolephorus commersonii) was conducted in December 2018 for 10 days by operating boat lift nets using green, blue and green-blue LED lights.  The results showed that the use of LED light colors in blue water had a very significant effect on the amount of anchovy catch (Stolephorus comersonii) compared to to the color of LED lights in green-blue and green water.  Whereas the use of LED light colors in blue-green water with green is not statistically significantly different from the amount of anchovy caught (Stolephorus comersonii).ABSTRAKBagan merupakan salah satu alat penangkapan ikan yang dioperasikan pada malam hari.  Alat tangkap ini menggunakan cahaya lampu sebagai alat bantu untuk menarik ikan masuk ke dalam area penangkapan.  Penelitian mengenai penggunaan lampu LED dalam air pada bagan dilakukan di Perairan Tateli Weru, dengan tujuan untuk melihat bagaimana pengaruh penggunaan lampu LED bawah air dengan warna yang berbeda terhadap hasil tangkapan ikan teri (Stolephorus commersonii), serta mengetahui jumlah hasil tangkapan ikan teri (Stolephorus commersonii) pada bagan dengan menggunakan metode eksperimental, dimana data dianalisis dengan menggunakan  Rancangan Acak Kelompok (RAK) dan dilanjutkan dengan uji Beda Nyata Terkecil (BNT).  Uji coba penangkapan ikan teri (Stolephorus commersonii) dilakukan pada bulan Desember 2018 selama 10 hari dengan mengoperasikan bagan apung menggunakan lampu LED hijau, biru dan hijau-biru.  Hasil penelitian menunjukkan bahwa penggunaan warna lampu LED dalam air biru memberikan pengaruh yang sangat nyata terhadap jumlah hasil tangkapan ikan teri (Stolephorus comersonii) dibandingkan warna lampu LED dalam air hijau-biru dan hijau.  Sedangkan antara penggunaan warna lampu LED dalam air hijau-biru dengan hijau secara statistik tidak berbeda nyata terhadap jumlah hasil tangkapan ikan teri (Stolephorus comersonii)

A Simple Grand Unified Relation between Neutrino Mixing and Quark Mixing

It is proposed that all flavor mixing is caused by the mixing of the three quark and lepton families with vectorlike fermions in 5 + 5-bar multiplets of SU(5). This simple assumption implies that both V_{CKM} and U_{MNS} are generated by a single matrix. The entire 3-by-3 complex mass matrix of the neutrinos M_{nu} is then found to have a simple expression in terms of two complex parameters and an overall scale. Thus, all the presently unknown neutrino parameters are predicted. The best fits are for theta_{atm} less than or approximately 40 degrees. The leptonic Dirac CP phase is found to be somewhat greater than pi radians.Comment: 10 pages, 4 figures, one table. Typos correcte

Universality in the Screening Cloud of Dislocations Surrounding a Disclination

A detailed analytical and numerical analysis for the dislocation cloud surrounding a disclination is presented. The analytical results show that the combined system behaves as a single disclination with an effective fractional charge which can be computed from the properties of the grain boundaries forming the dislocation cloud. Expressions are also given when the crystal is subjected to an external two-dimensional pressure. The analytical results are generalized to a scaling form for the energy which up to core energies is given by the Young modulus of the crystal times a universal function. The accuracy of the universality hypothesis is numerically checked to high accuracy. The numerical approach, based on a generalization from previous work by S. Seung and D.R. Nelson ({\em Phys. Rev A 38:1005 (1988)}), is interesting on its own and allows to compute the energy for an {\em arbitrary} distribution of defects, on an {\em arbitrary geometry} with an arbitrary elastic {\em energy} with very minor additional computational effort. Some implications for recent experimental, computational and theoretical work are also discussed.Comment: 35 pages, 21 eps file

Strong Pinning in High Temperature Superconductors

Detailed measurements of the critical current density jc of YBa2Cu3O7 films grown by pulsed laser deposition reveal the increase of jc as function of the filmthickness. Both this thickness dependence and the field dependence of the critical current are consistently described using a generalization of the theory of strong pinning of Ovchinnikov and Ivlev [Phys. Rev. B 43, 8024 (1991)]. From the model, we deduce values of the defect density (10^21 m^-3) and the elementary pinning force, which are in good agreement with the generally accepted values for Y2O3-inclusions. In the absence of clear evidence that the critical current is determined by linear defects or modulations of the film thickness, our model provides an alternative explanation for the rather universal field dependence of the critical current density found in YBa2Cu3O7 films deposited by different methods.Comment: 11 pages; 8 Figures; Published Phys. Rev. B 66, 024523 (2002

Observation of the Smectic C -- Smectic I Critical Point

We report the first observation of the smectic C--smectic I (C--I) critical point by Xray diffraction studies on a binary system. This is in confirmity with the theoretical idea of Nelson and Halperin that coupling to the molecular tilt should induce hexatic order even in the C phase and as such both C and I (a tilted hexatic phase) should have the same symmetry. The results provide evidence in support of the recent theory of Defontaines and Prost proposing a new universality class for critical points in layered systems.Comment: 9 pages Latex and 5 postscript figures available from [email protected] on request, Phys.Rev.Lett. (in press

2015 Update on Acute Adverse Reactions to Gadolinium based Contrast Agents in Cardiovascular MR. Large Multi-National and Multi-Ethnical Population Experience With 37788 Patients From the EuroCMR Registry

Objectives: Specifically we aim to demonstrate that the results of our earlier safety data hold true in this much larger multi-national and multi-ethnical population. Background: We sought to re-evaluate the frequency, manifestations, and severity of acute adverse reactions associated with administration of several gadolinium- based contrast agents during routine CMR on a European level. Methods: Multi-centre, multi-national, and multi-ethnical registry with consecutive enrolment of patients in 57 European centres. Results: During the current observation 37788 doses of Gadolinium based contrast agent were administered to 37788 patients. The mean dose was 24.7 ml (range 5–80 ml), which is equivalent to 0.123 mmol/kg (range 0.01 - 0.3 mmol/kg). Forty-five acute adverse reactions due to contrast administration occurred (0.12 %). Most reactions were classified as mild (43 of 45) according to the American College of Radiology definition. The most frequent complaints following contrast administration were rashes and hives (15 of 45), followed by nausea (10 of 45) and flushes (10 of 45). The event rate ranged from 0.05 % (linear non-ionic agent gadodiamide) to 0.42 % (linear ionic agent gadobenate dimeglumine). Interestingly, we also found different event rates between the three main indications for CMR ranging from 0.05 % (risk stratification in suspected CAD) to 0.22 % (viability in known CAD). Conclusions: The current data indicate that the results of the earlier safety data hold true in this much larger multi-national and multi-ethnical population. Thus, the “off-label” use of Gadolinium based contrast in cardiovascular MR should be regarded as safe concerning the frequency, manifestation and severity of acute events