Electromagnetic wave propagation in spatially homogeneous yet smoothly time-varying dielectric media

We explore the propagation and transformation of electromagnetic waves through spatially homogeneous yet smoothly time-dependent media within the framework of classical electrodynamics. By modelling the smooth transition, occurring during a finite period {\tau}, as a phenomenologically realistic and sigmoidal change of the dielectric permittivity, an analytically exact solution to Maxwell's equations is derived for the electric displacement in terms of hypergeometric functions. Using this solution, we show the possibility of amplification and attenuation of waves and associate this with the decrease and increase of the time-dependent permittivity. We demonstrate, moreover, that such an energy exchange between waves and non-stationary media leads to the transformation (or conversion) of frequencies. Our results may pave the way towards controllable light-matter interaction in time-varying structures.Comment: 5 figure

Oxidized and reduced kaolin fan deposits: Their sedimentological-mineralogical facies and physical-chemical regime (North-Bavarian Kaolin Mining District, Germany)

The kaolin-fan deposits under consideration are sedimentary in origin and they bridge the gap between residual kaolin deposits proximal to the fan apex in crystalline basement rocks and syn(dia)genetic sandstone-hosted kaolin deposits on the fan apron. The “kaolin ore beds” on the other hand, developed in an arenaceous braided-river drainage system (bed load >>> suspended load deposits), reworking into secondary kaolin deposits that took place either intraformationally during the evolution of the kaolin fan deposits or epigenetically after unroofing of the kaolin deposits in high-sinuosity drainage systems passing, locally, into ephemeral lakes and mud flats (suspended load > bed load deposits). The reference type for kaolin fan deposits has been studied in terrigeneous sediments which are largely mined at Hirschau–Schnaittenbach, along the Western edge of the Bohemian Massif, SE Germany. The fan deposits formed under alternating wet and dry subtropical climatic conditions during the early Triassic. Different intensities of uplift in the hinterland and the frequency of tectonic quiescence to tectonic pulse had a strong impact on the paleogradient, facies and hydrography of the kaolin fan deposits, resulting in the build-up of oxidized kaolin fans (OKF) and reduced kaolin fans (RKF). The OKF provide favorable conditions for the accumulation and preservation of kaolin deposits of economic potential, due to a low paleogradient and a continuous rate of uplift. The opposite is the case in the RKF that formed more proximal to the initial residual kaolin deposits and, more basinward, grade into sandstone-hosted (non)-sulfidic faciesbound Pb deposits that were targeted upon during exploration campaigns in the study area. The mineral association of the kaolin fan deposits has been categorized as follows: the allochthonous heavy minerals are zircon, tourmaline, apatite, monazite, xenotime, rutile, garnet, titaniferous magnetite, and ilmenite. They do not significantly vary between OKF and RKF. The autochthonous heavy minerals show strong contrasts in their heavy mineral suites. The RKF are enriched in sulfides and arsenides, which can be deleterious for the kaolin raw material and exclude its use for special final products (anatase, hematite, galena, sphalerite, marcasite, pyrite, bravoite (Ni pyrite), “limonite”, goethite, Ag–Cu–Ni–As sulfides, and barite). The OKF are rather poor in accessory minerals and contain anatase, hematite, and APS minerals. The latter are geo-acidometers (marker minerals for low pH) and considered as an ore guide to high-potential target areas for kaolin. The allochthonous light minerals quartz and K feldspar are common to both fan types and were only in parts affected by kaolinization, whereas plagioclase has been decomposed to completeness. Autochthonous light minerals quartz, chalcedony (carnelian), and calcite are exclusive to the RKF, where silcretes and calcretes evolved in those stratigraphic units which in the OKF only brought about Ca, Fe and Ti anomalies. The OKF have a significant edge over the RKF in terms of kaolin quality and kaolin exploitation (providing less mechanical wear on LHD [load–haul–dump machinery] machinery). Allochthonous phyllosilicates have a more widespread occurrence in the RKF with muscovite, biotite and chlorite most common in the lowermost kaolin beds. By quality there is not much difference among the autochthonous phyllosilicates of the OKF and RKF. Kaolinite-group minerals, illite, smectite, and an illite–smectite mixed-layer are present in both types, but kaolinite-group minerals prevail in the OKF, with a downward-increasing trend of dickite. By contrast the amount of smectite and smectite–illite mixed layers increases at the expense of kaolinite upward in the stratigraphy. The evolution of the kaolin fan deposits can be subdivided into six stages. Each stage is representative of a peculiar process which translates into concentration, preservation and destruction of kaolin: stage 1 weathering and the formation of a kaolin regolith (constructive), stage 2 transport, deposition synsedimentary to early-diagenetic kaolinization (constructive + preserving), stage 3 synsedimentary to early-diagenetic smectitization of kaolin (faciesbound Pb mineralization only in the RKF) (preserving + destructive), stage 4 late-diagenetic kaolinization and formation of dickite (preserving + constructive) (not in RKF), stage 5 epigenetic unconformity-related Cu–Ag–Ni–As–Ba mineralization (vaguely expressed in the OKF) (preserving), and stage 6 unroofing, erosion and redeposition of kaolin (only in the OKF) (destructive). During the study a PIMA device has proven in this type of kaolin deposit to be an efficacious tool for capturing digital data in the field of exploitation and exploration of industrial minerals for the identification and quantification of clay minerals (quality control)

Experimental investigation of ultracold atom-molecule collisions

Ultracold collisions between Cs atoms and Cs2 dimers in the electronic ground state are observed in an optically trapped gas of atoms and molecules. The Cs2 molecules are formed in the triplet ground state by cw-photoassociation through the outer well of the 0g-(P3/2) excited electronic state. Inelastic atom-molecule collisions converting internal excitation into kinetic energy lead to a loss of Cs2 molecules from the dipole trap. Rate coefficients are determined for collisions involving Cs atoms in either the F=3 or F=4 hyperfine ground state and Cs2 molecules in either highly vibrationally excited states (v'=32-47) or in low vibrational states (v'=4-6) of the a ^3 Sigma_u^+ triplet ground state. The rate coefficients beta ~10^{-10} cm^3/s are found to be largely independent of the vibrational and rotational excitation indicating unitary limited cross sections.Comment: 4 pages, 3 figures, submitted for publicatio

Extracting Multidimensional Phase Space Topology from Periodic Orbits

We establish a hierarchical ordering of periodic orbits in a strongly coupled multidimensional Hamiltonian system. Phase space structures can be reconstructed quantitatively from the knowledge of periodic orbits alone. We illustrate our findings for the hydrogen atom in crossed electric and magnetic fields.Comment: 4 pages, 5 figures, accepted for publication in Phys. Rev. Let

A Systematic Review on the Effects of Plant-Feeding by Omnivorous Arthropods: Time to Catch-Up With the Mirid-Tomato Bias?

Zoophytophagous (omnivorous) predators provide valuable pest control services, and offer an advantage over strict carnivores as plant-feeding enables survival during prey shortage. This putative advantage can potentially be their downside, as plant-feeding may entail damage that negatively affects plant growth/yield (i.e., the cost arising from of omnivore plant-feeding). Yet, benefits conferred by predatory services are usually thought to counterbalance any impact of plant damage. In this systematic review, our goal was to determine how often levels of omnivore damage and its consequences for plants (costs) are considered or quantified. We provide a synthesis of publication trends and findings on omnivore plant-feeding levels, plant injury variables, actual (if quantified) and potential effects on growth/yield, the type of study (lab, greenhouse) and the plants/omnivores most often examined. Our search revealed that measures of omnivore plant-feeding are occasionally reported, but seldom are the direct consequences of such damage also considered. Omnivore plant-feeding were reported in 57% of studies (53 of 93 full-text examined); within these, the majority (>80%) indicated moderate to high levels of plant-feeding. However, only 22% of reports (15 of 69) quantified the effects of omnivore-inflicted damage on plant performance. Of these 15 reports, a greater number found negative consequences for plants compared to those showing no effect (8 vs. 4; 3 with both), with consequences for yield relative to growth being more often evaluated (6 vs. 2). Overall, fruit/leaf injuries relative to stem/flower-feeding were most often examined, and lab/greenhouse experiments predominated. Tomatoes (Solanum lycopersicum) and the mirid Nesidiocoris tenuis were the most common species studied (34 and 14 reports, respectively). Our results indicate that costs to plants of omnivore-inflicted damage are often neglected. We argue that predatory benefits need to be simultaneously considered with plant-feeding effects to appropriately evaluate pest control services. Publication trends suggest that more studies are evaluating costs to plants, but a paradigm shift is still needed. Furthermore, we found that our understanding of plant-feeding and its effects is disproportionally based on studies examining tomato plants and its omnivorous biocontrol agents. To confirm the generality of findings thus far, other plant omnivore systems should be further considered

Hochschulräte als neues Steuerungsinstrument? Eine empirische Analyse der Mitglieder und Aufgabenbereiche

Die vorliegende Studie liefert erstmalig einen repräsentativen Überblick über die Struktur, die Zusammensetzung und erste Erfahrungen mit den Arbeitsweisen von Hochschulräten in Deutschland, Österreich und der Schweiz. Hochschulräte werden als neue Steuerungsinstrumente im "Mehrebenensystem" von Hochschulen gesehen, die auf den von Sozialwissenschaftlern konstatierten Trend zu einer "Zerfaserung" von Staatlichkeit hinweisen und zu einer Verschiebung von Organisationsverantwortung beitragen können. (Textauszug

Incorporation of phosphatidylserine improves efficiency of lipid based gene delivery systems

The essential homeostatic process of dead cell clearance (efferocytosis) is used by viruses in an act of apoptotic mimicry. Among others, virions leverage phosphatidylserine (PS) as an essential "eat me" signal in viral envelopes to increase their infectivity. In a virus-inspired biomimetic approach, we demonstrate that PS can be incorporated into non-viral lipid nanoparticle (LNP) pDNA/mRNA constructs to enhance cellular transfection. The inclusion of the bioactive PS leads to an increased ability of LNPs to deliver nucleic acids in vitro to cultured HuH-7 hepatocellular carcinoma cells resulting in a 6-fold enhanced expression of a transgene. Optimal PS concentrations are in the range of 2.5 to 5% of total lipids. PS-decorated mRNA-LNPs show a 5.2-fold enhancement of in vivo transfection efficiency as compared to mRNA-LNPs devoid of PS. Effects were less pronounced for PS-decorated pDNA-LNPs (3.2-fold increase). Incorporation of small, defined amounts of PS into gene delivery vectors opens new avenues for efficient gene therapy and can be easily extended to other therapeutic systems

Country-wide HIV incidence study complementing HIV surveillance in Germany

Serological methods exist that allow differentiating between recent and long-standing infections in persons infected with HIV. During a pilot study in Berlin between 2005 and 2007 methodologies have been evaluated. In a cross-sectional study blood samples, demographic, laboratory, clinical and behavioural data based on a KABP survey were collected from patients with newly diagnosed HIV infections. The BED-CEIA was used to determine recency of infection. Recent HIV infections contributed 54% (CI [95%]: 45; 64) in MSM and 16% (CI [95%]: 0; 39) in patients with other transmission risks (p=0.041). Proportions of recent infections were significantly higher in MSM ≤30 years (p=0.019). The mean age was 33.9 (median 34 years) in recent compared with 38.6 years (median: 38 years) in long-standing infections (p=0.011). High-risk behaviour indicated through very low condom use in recently HIV infected MSM could be identified. The results of the pilot study support expectations that the modified application of the method may contribute to improving HIV prevention efforts in Germany. On this basis the Robert Koch Institute implemented a countrywide HIV incidence study to complement HIV surveillance in early 2008. The study is funded by the German Ministry of Health. Data on recent HIV infections and current HIV transmission risks are collected. Design, methods and impact are described in detail

Successful long-term monotherapy with rituximab in a patient with chronic lymphocytic leukemia of the B-cell-lineage: a case report

<p>Abstract</p> <p>Introduction</p> <p>Treatment of chronic lymphocytic leukemia of the B-cell-lineage is strongly based upon clinical staging because of the heterogeneous clinical course of this disease.</p> <p>Case presentation</p> <p>We describe a 62-year-old patient with newly diagnosed chronic lymphocytic leukemia of the B-cell-lineage who did not respond to several chemotherapy regimens including chlorambucil, fludarabine and cyclophosphamide, developing a marked neutropenia and thrombocytopenia with life-threatening infections. Further chemotherapy appeared not feasible because of bone marrow toxicity. The patient was treated with 600 mg/m²rituximab weekly followed by eight courses of biweekly therapy and then by long-term maintenance therapy, achieving almost complete remission of the symptoms and disease control.</p> <p>Conclusion</p> <p>After resistance to standard chemotherapy with chlorambucil and fludarabine, a patient with chronic lymphocytic leukemia of the B-cell-lineage was successfully treated with rituximab.</p