Systematics and Chatacteristics

The "Tracheophyte Phylogeny Poster – Vascular Plants - Systematics and Characteristics" is an educational tool presenting an overview of the evolutionary relationships among non-flowering vascular plants (lycophytes, monilophytes, and gymnosperms). The phylogenetic tree depicts the orders and families (lycophytes and monilophytes) and the genera of gymnosperms, listing the main apomorphies and plesiomorphies as well as diagnostic and nondiagnostic anatomical and morphological features within the tree. The intuitive color-coding facilitates memorization and teaching. Translations of the poster by internationally renown botanists in various world languages is in progress. This is one in a series of three educational posters on the phylogeny of land plants: Poster 1: "Angiosperms", Poster 2: "Tracheophytes: Lycophytes, Ferns, Gymnosperms", Poster 3: "Bryophytes: Liverworts, Mosses, Hornworts"

Phylogenie und Systematik der Gefäßpflanzen

Das Lehr- und Lernposter „Stammbaum der Tracheophyten – Phylogenie und Systematik der Gefäßpflanzen“ gibt einen Überblick a) über die Phylogenie (Stammesgeschichte) der „Farnverwandten“ (Lycophyten und Monilophyten, die „Farne“) bis zu den Familien und b) über die Gymnospermen (Nacktsamer) bis zu den Gattungen. Innerhalb des Baumes werden die hauptsächlichen ursprünglichen und abgeleiteten Merkmale (Plesio- und Apomorphien) sowie typische anatomische und morphologische Merkmale bis zur Stufe der Familien (Gymnospermen) bzw. Ordnungen (Farnpflanzen) und höherer Gruppen aufgeführt. Die farbliche Abstimmung der Großgruppen erleichtert das Lehren und Lernen. Das Poster ist das zweite in einer Reihe, die die Phylogenie der Landpflanzen darstellt. Poster 1 umfasst die Angiospermen (Blütenpflanzen), Poster 3 die „Moose“ (Leber-, Laub- und Hornmoose). In einer Zusammenarbeit mit international renommierten Botanikern sind wir bemüht, die Poster in eine Vielzahl anderer Sprachen übersetzen zu lassen.Stand: Juli 201

Systematik der Blütenpflanzen

Dieses für Lehrzwecke entwickelte "Angiosperm Phylogeny Poster – Flowering Plant Systematics" zeigt einen Überblick über die Phylogenie der Samenpflanzen und dazugehörige evolutionäre Entwicklungen. Es basiert auf der letzten Veröffentlichung der Angiosperm Phylogeny Group (APG IV) und der Onlineressource APWeb von Peter F. Stevens (Missouri Botanical Garden). Der Baum umfasst 64 Ordnungen und die überwiegende Zahl der 416 Familien, die hauptsächlichen ursprünglichen und abgeleiteten Merkmale (Plesio- und Apomorphien) sowie typische anatomische, morphologische und phytochemische Merkmale der Ordnungen und höherer Gruppen innerhalb des Baumes. Die farbliche Abstimmung der Großgruppen erleichtert Lehren und Lernen. Dank der Zusammenarbeit mit international bekannten Botanikern sind wir jetzt in der Lage, dieses Poster in knapp 20 Sprachen anbieten zu können. In der ebenfalls auf Refubium verfügbaren englischen Version https://refubium.fu-berlin.de/handle/fub188/18972 führen Hyperlinks zu ausführlichen Beschreibungen im APweb. Zwei weitere Poster bieten eine entsprechende Übersicht über die Tracheophyten ("Farnpflanzen" und Nacktsamer) und "Moose" (Leber-, Laub- und Hornmoose).April 2016 / deutsche Versio

X-ray diffraction measurements of the c-axis Debye-Waller factors of YBa2Cu3O7 and HgBa2CaCu2O6

We report the first application of x-rays to the measurement of the temperature dependent Bragg peak intensities to obtain Debye-Waller factors on high-temperature superconductors. Intensities of (0,0,l) peaks of YBa2Cu3O7 and HgBa2CaCu2O6 thin films are measured to obtain the c-axis Debye-Waller factors. While lattice constant and some Debye-Waller factor measurements on high Tc superconductors show anomalies at the transition temperature, our measurements by x-ray diffraction show a smooth transition of the c-axis Debye-Waller factors through T$_c$. This suggests that the dynamic displacements of the heavy elements along the c-axis direction in these compounds do not have anomalies at Tc. This method in combination with measurements by other techniques will give more details concerning dynamics of the lattice.Comment: 4 pages, 2 figures. To be published in Physical Review B (Brief Report

Relations between fusion cross sections and average angular momenta

We study the relations between moments of fusion cross sections and averages of angular momentum. The role of the centrifugal barrier and the target deformation in determining the effective barrier radius are clarified. A simple method for extracting average angular momentum from fusion cross sections is demonstrated using numerical examples as well as actual data.Comment: 16 REVTeX pages plus 8 included Postscript figures (uses the epsf macro); submitted to Phys. Rev. C; also available at http://nucth.physics.wisc.edu/preprint

Reduced Tissue-Level Stiffness and Mineralization in Osteoporotic Cancellous Bone

Osteoporosis alters bone mass and composition ultimately increasing the fragility of primarily cancellous skeletal sites; however, effects of osteoporosis on tissue-level mechanical properties of cancellous bone are unknown. Dual-energy x-ray absorptiometry (DXA) scans are the clinical standard for diagnosing osteoporosis though changes in cancellous bone mass and mineralization are difficult to separate using this method. The goal of this study was to investigate possible difference in tissue-level properties with osteoporosis as defined by donor T-scores. Spine segments from Caucasian female cadavers (58–92 yrs) were used. A T-score for each donor was calculated from DXA scans to determine osteoporotic status. Tissue level composition and mechanical properties of vertebrae adjacent to the scan region were measured using nanoindentation and Raman spectroscopy. Based on T-scores, six samples were in the Osteoporotic group (58–74 yrs) and four samples were in the Not Osteoporotic group (65–92 yrs). The indentation modulus and mineral to matrix ratio (mineral:matrix) were lower in the Osteoporotic group than the Not Osteoporotic group. Mineral:matrix ratio decreased with age (r2 = 0.35, p = 0.05), and the indentation modulus increased with a real bone mineral density (aBMD) (r2 = 0.41, p = 0.04)

The Biology Instrument for the Viking Mars Mission

Two Viking spacecraft have successfully soft landed on the surface of Mars. Each carries, along with other scientific instruments, one biology laboratory with three different experiments designed to search for evidence of living microorganisms in material sampled from the Martian surface. This 15.5-kg biology instrument which occupies a volume of almost 28.3 dm3 is the first to carry out an in situ search for extraterrestrial life on a planet. The three experiments are called the pyrolytic release, labeled release, and gas exchange. The pyrolytic release experiment has the capability to measure the fixation of carbon dioxide or carbon monoxide into organic matter. The labeled release experiment detects metabolic processes by monitoring the production of volatile carbon compounds from a radioactively labeled nutrient mixture. The gas exchange experiment monitors the gas changes in the head space above a soil sample which is either incubated in a humid environment or supplied with a rich organic nutrient solution. Each experiment can analyze a soil sample as it is received from the surface or, as a control, analyze a soil which has been heated to above 160C. Each instrument has the capability to receive four different soils dug from the Martian surface and perform a number of analysis cycles depending on the particular experiment. This paper describes in detail the design and operation of the three experiments and the supporting subsystems

Stability analysis of agegraphic dark energy in Brans-Dicke cosmology

Stability analysis of agegraphic dark energy in Brans-Dicke theory is presented in this paper. We constrain the model parameters with the observational data and thus the results become broadly consistent with those expected from experiment. Stability analysis of the model without best fitting shows that universe may begin from an unstable state passing a saddle point and finally become stable in future. However, with the best fitted model, There is no saddle intermediate state. The agegraphic dark energy in the model by itself exhibits a phantom behavior. However, contribution of cold dark matter on the effective energy density modifies the state of teh universe from phantom phase to quintessence one. The statefinder diagnosis also indicates that the universe leaves an unstable state in the past, passes the LCDM state and finally approaches the sable state in future.Comment: 15 pages, 12 figure

Location of crossings in the Floquet spectrum of a driven two-level system

Calculation of the Floquet quasi-energies of a system driven by a time-periodic field is an efficient way to understand its dynamics. In particular, the phenomenon of dynamical localization can be related to the presence of close approaches between quasi-energies (either crossings or avoided crossings). We consider here a driven two-level system, and study how the locations of crossings in the quasi-energy spectrum alter as the field parameters are changed. A perturbational scheme provides a direct connection between the form of the driving field and the quasi-energies which is exact in the limit of high frequencies. We firstly obtain relations for the quasi-energies for some common types of applied field in the high-frequency limit. We then show how the locations of the crossings drift as the frequency is reduced, and find a simple empirical formula which describes this drift extremely well in general, and appears to be exact for the specific case of square-wave driving.Comment: 6 pages, 6 figures. Minor changes to text, this version to be published in Physical Review