Pesticide exposure enhances dominance patterns in a zooplankton community

Exposure to pesticides can profoundly alter community dynamics. It is expected that dominance patterns will be enhanced or reduced depending on whether the dominant species is less or more sensitive to the pesticide than the subdominant species. Community dynamics are, however, also determined by processes linked to population growth as well as competition at carrying capacity. Here, we used a mesocosm experiment to quantify the effect of chlorpyrifos exposure on the population dynamics of four cladoceran species (Daphnia magna, Daphnia pulicaria, Daphnia galeata and Scapholeberis mucronata) in mixed cultures, testing for direct effects of chlorpyrifos and indirect effects mediated by interactions with other species on the timing of population growth and dominance at carrying capacity. We also quantified whether the pesticide-induced changes in community dynamics affected top-down control of phytoplankton. By adding a treatment in which we used different genotype combinations of each species, we also tested to what extent genetic composition affects community responses to pesticide exposure. Immobilization tests showed that D. magna is the least sensitive to chlorpyrifos of the tested species. Chlorpyrifos exposure first leads to a reduction in the abundance of D. galeata to the benefit of D. pulicaria, and subsequently to a reduction in densities of D. pulicaria to the benefit of D. magna. This resulted in D. magna being more dominant in the pesticide than in the control treatment by the end of the experiment. There was no effect of genotypic differences on community patterns, and top-down control of phytoplankton was high in all treatments. Our results suggest that in this community dominance patterns are enhanced in line with the observed among-species differences in sensitivity to the pesticide. Our results also show that the development of the community in pesticide treatment is a complex interaction between direct and indirect effects of the pesticide.

Socio-economic or environmental benefits from pondscapes? Deriving stakeholder preferences using analytic hierarchy process and compositional data analysis

Ponds occupy a large share of standing water worldwide and play an important role in providing various ecosystem services. There are concerted efforts of the European Union either to create new ponds, or to restore and preserve existing ponds as nature-based solutions to provide benefits to ecosystem and human well-being. As part of the EU PONDERFUL project, selected pondscapes (i.e. landscapes of ponds) in eight different countries - hereafter "demo-sites", are studied to comprehensively understand their characteristics and their efficiency to provide ecosystem services. In addition, the needs and knowledge of stakeholders who own, work, research, or benefit from the pondscapes are also important, because of their capabilities to create, manage and develop the pondscapes. Therefore, we established connection with stakeholders to study their preferences and visions on the pondscapes. Using the analytic hierarchy process, this study shows that in general stakeholders in the European and Turkish demo-sites prefer environmental benefits to economic benefits, while stakeholders in the Uruguayan demo-sites rank the economic benefits higher. More specifically, in the European and Turkish demo-sites, the biodiversity benefits, i.e. life-cycle maintenance, habitat and gene pool protection, receive the highest ranking among all groups. On the other hand, stakeholders at the Uruguayan demo-sites rank provisioning benefits as the most important, because many ponds in Uruguayan demo-sites are being used for agricultural purposes. Understanding those preferences helps policy makers to address the needs of stakeholders more correctly, when considering any action or policy for the pondscapes.

Drought altered trophic dynamics of an important natural saline lake: A stable isotope approach

Climate change and associated droughts threaten the ecology and resilience of natural saline lakes globally. There is a distinct lack of research regarding their ecological response to climatic events in the Global South. This region is predicted to experience climatic events such as El Niño-Southern Oscillation (ENSO) more often and with greater severity with the potential to alter the structure and functioning of aquatic ecosystems significantly. From 2015 to 2016 South Africa experienced one of the most severe country-wide droughts as a result of a strong ENSO event. Our study aimed to investigate the effect of this supra-seasonal drought on the trophic structure of fish communities in a naturally saline shallow lake of a Ramsar wetland using stable isotope techniques. Fishes and potential basal sources were collected from the lake, during predrought conditions in 2010 and after severe drought (recovery phase; 2017). The δ¹³C and δ¹⁵N values of food web elements were determined and analysed using Bayesian mixing models and Bayesian Laymen metrics to establish the proportional contribution of C₃ and C₄ basal sources to the fish (consumer) diets, and examine the fish community in terms of isotopic niche and trophic structure, respectively. Fish consumers relied predominantly on C₃ basal sources in the predrought and shifted to greater reliance on C₄ basal sources, decreased isotopic niche space use and a reduction in trophic length in the recovery phase. Drought altered the type and abundance of the basal sources available by limiting sources to those that are more drought-tolerant, reducing the trophic pathways of the food web with no significant alterations in the fish community. These results demonstrate the resilience and biological plasticity of Lake Nyamithi and its aquatic fauna, highlighting the importance of freshwater inflow to saline lakes with alterations thereof posing a significant threat to their continued functioning.

Differential local genetic adaptation to pesticide use in organic and conventional agriculture in an aquatic non-target species

Pesticide application is an important stressor to non-target species and can profoundly affect ecosystem functioning. Debates continue on the choice of agricultural practices regarding their environmental impact, and organic farming is considered less detrimental compared to conventional practices. Nevertheless, comparative studies on the impacts of both agricultural approaches on the genetic adaptation of non-target species are lacking. We assessed to what extent organic and conventional agriculture elicit local genetic adaptation of populations of a non-target aquatic species, Daphnia magna. We tested for genetic differences in sensitivity of different D. magna populations (n = 7), originating from ponds surrounded by conventional and organic agriculture as well as nature reserves, to pesticides used either in conventional (chlorpyrifos) or organic agriculture (deltamethrin and copper sulfate). The results indicate that D. magna populations differentially adapt to local pesticide use. Populations show increased resistance to chlorpyrifos as the percentage of conventional agriculture in the surrounding landscape increases, whereas populations from organic agriculture sites are more resistant to deltamethrin. While organic agriculture is considered less harmful for non-target species than conventional, both types of agriculture shape the evolution of pesticide resistance in non-target species in a specific manner, reflecting the differences in selection pressure.

Association between Labeobarbus spp. (Teleostei: Cyprinidae) and environmental variables in the Luhoho basin (Eastern Congo River basin; DRC)

The African cyprinid genus Labeobarbus is characterized by a high polymorphism in mouth morphology. The association between four species of this genus (two chiselmouths, one rubberlip with a well-developed fleshy mental lobe on the lower jaw, i.e., a fleshy appendage on the chin, and one usually with a poorly developed one) and 26 environmental variables was investigated in four affluents of the Luhoho River in the Albertine Highlands of the Upper Congo basin. A combination of univariate and multivariate analyses suggested that differences exist in habitat composition at localities where different Labeobarbus species were reported, and within different mouth phenotypes. The association of L. longidorsalis with the presence of cobbles and pebbles and of L. brauni with the presence of boulders suggests that the occurrence of chiselmouths phenotype is associated with stony habitats, whereas phenotypes with a mental lobe, i.e., Labeobarbus longifilis and L. paucisquamatus, mostly occupy habitats without stones. Differences in the distribution between these two species appear to be linked to physico-chemical parameters such as electrical conductivity and water temperature rather than substrate type. The findings of this study are relevant for developing guidelines that aim effective local preservation and conservation of these Labeobarbus species.

Experimental Evaluation of a Cell Module for Hybrid Liver Support

Aim of the study was to evaluate a hybrid liver support system in a porcine model of acute liver failure, after hepatectomy. Pigs with a body weight of 70±18 kg underwent total hepatectomy and porto - cavo - caval shunting as well as ligation of the bile duct and the hepatic artery. Control animals were connected to the system (including capillary membrane plasma separation) containing a four compartment bioreactor with integral oxygenation and decentralized mass exchange but without liver cells. The treatment group received hybrid liver support with the same system including 370±42 g primary isolated porcine parenchymal liver cells in co-culture with hepatocyte nursing cells, tissue engineered to liver- like structures at high density. Treatment started after complete recovery from anesthesia and was performed continuously. A positive influence on peripheral vascular resistance and a reduced need of catecholamine dosage was observed in the treatment group. Hybrid liver support with a cell module upscaled for clinical application significantly prolonged survival time in animals after hepatectomy with the longest survival being 26 hours in the control group an 57 hours in the treatment group.

Extracorporeal Lung Assist with Heparin-Coated Systems

Extracorporeal lung assist (ELA) has been recommended for the treatment of ARDS if conventional therapy fails. However, the need for nearly complete anticoagulation is a major risk factor for hemorrhagic complications. We describe our experience with 13 ARDS patients treated with ELA using heparin-coated systems (Carmeda). Maintaining partial thromboplastin time and activated clotting time within or close to the normal range, even major surgery (20 thoracotomies and 2 laparotomies) could be performed without undue bleeding complications related to anticoagulation during extracorporeal support. Eight of the 13 patients survived. The use of heparin-coated systems allows prolonged ELA with nearly physiological coagulation function, permitting major surgical intervention. It enhances the safety margin of extracorporeal gas exchange and may ultimately extend its indications.

Rapid evolution leads to differential population dynamics and top-down control in resurrected Daphnia populations

There is growing evidence of rapid genetic adaptation of natural populations to environmental change, opening the perspective that evolutionary trait change may subsequently impact ecological processes such as population dynamics, community composition, and ecosystem functioning. To study such eco‐evolutionary feedbacks in natural populations, however, requires samples across time. Here, we capitalize on a resurrection ecology study that documented rapid and adaptive evolution in a natural population of the water flea Daphnia magna in response to strong changes in predation pressure by fish, and carry out a follow‐up mesocosm experiment to test whether the observed genetic changes influence population dynamics and top‐down control of phytoplankton. We inoculated populations of the water flea D. magna derived from three time periods of the same natural population known to have genetically adapted to changes in predation pressure in replicate mesocosms and monitored both Daphnia population densities and phytoplankton biomass in the presence and absence of fish. Our results revealed differences in population dynamics and top‐down control of algae between mesocosms harboring populations from the time period before, during, and after a peak in fish predation pressure caused by human fish stocking. The differences, however, deviated from our a priori expectations. An S‐map approach on time series revealed that the interactions between adults and juveniles strongly impacted the dynamics of populations and their top‐down control on algae in the mesocosms, and that the strength of these interactions was modulated by rapid evolution as it occurred in nature. Our study provides an example of an evolutionary response that fundamentally alters the processes structuring population dynamics and impacts ecosystem features.

The influence of balanced and imbalanced resource supply on biodiversity-functioning relationship across ecosystems

Numerous studies show that increasing species richness leads to higher ecosystem productivity. This effect is often attributed to more efficient portioning of multiple resources in communities with higher numbers of competing species, indicating the role of resource supply and stoichiometry for biodiversity-ecosystem functioning relationships. Here, we merged theory on ecological stoichiometry with a framework of biodiversity-ecosystem functioning to understand how resource use transfers into primary production. We applied a structural equation model to define patterns of diversity-productivity relationships with respect to available resources. Meta-analysis was used to summarize the findings across ecosystem types ranging from aquatic ecosystems to grasslands and forests. As hypothesized, resource supply increased realized productivity and richness, but we found significant differences between ecosystems and study types. Increased richness was associated with increased productivity, although this effect was not seen in experiments. More even communities had lower productivity, indicating that biomass production is often maintained by a few dominant species, and reduced dominance generally reduced ecosystem productivity. This synthesis, which integrates observational and experimental studies in a variety of ecosystems and geographical regions, exposes common patterns and differences in biodiversity-functioning relationships, and increases the mechanistic understanding of changes in ecosystems productivity.

Modelling plexcitons of periodic gold nanorod arrays with molecular components

Plasmonic or exciton/plasmon (plexcitonic) systems are presently described based on electromagnetic models, ignoring the need for an improved microscopic understanding. This is based on the fact that a full quantum mechanical approach on a micrometer scale still represents a considerable challenge. In this paper we report on the experimental observation of plexcitons in 2D gold nanorod array systems coupled to dye molecules and we provide a description of the experimental data using a quantum model. We show that treating the collective behavior in the array as being represented by a single quasiparticle is a suitable approximation that offers the opportunity to avoid the complicated calculation of long-distance interactions between the individual nanoparticles of the plexcitonic, periodic system. This enables us to model the optical response of plasmons in nanostructured arrays in contact with quantum emitters and to derive microscopic informations. Our work provides a potential tool for the design of plexcitonic devices, which rely on periodic metallic nanostructures.

Love and Realism

In this reply I try to show that, contrary to Milberry's apparent assertion, the general intellect of the multitude does not have the explanatory robustness she accredits to it (following both Virno and the Hardt and Negri of the Empire trilogy). Digital network technologies are currently overwhelmingly effective in proletarianizing and disempowering the cognitariat and only an active technopolitics of deproletarianization could reverse this hegemonic situation. In my response to Verbeek, I attempt to correct his misinterpretation (shared by Milberry) of the Stieglerian approach as being dialectical in nature and show that, far from reinstating the humanist dichotomy between human beings and technologies, my analysis assumes their original, albeit fundamentally ambiguous and even 'uncanny' [unheimlich] interconnection. I conclude with pointing out some implications of this view for a 'really realistic' political theory of technology.

Social Autonomy and Heteronomy in the Age of ICT: The Digital Pharmakon and the (Dis)Empowerment of the General Intellect

'The art of living with ICTs (information and communication technologies)' today not only means finding new ways to cope, interact and create new lifestyles on the basis of the new digital (network) technologies individually, as 'consumer-citizens'. It also means inventing new modes of living, producing and, not in the least place, struggling collectively, as workers and producers. As the so-called digital revolution unfolds in the context of a neoliberal cognitive and consumerist capitalism, its 'innovations' are predominantly employed to modulate and control both production processes and consumer behavior in view of the overall goal of extracting surplus value. Today, the digital networks overwhelmingly destroy social autonomy, instead engendering increasing social heteronomy and proletarianization. Yet it is these very networks themselves, as technical pharmaka in the sense of French 'technophilosopher' Bernard Stiegler, that can be employed as no other to struggle against this tendency. This paper briefly explores this possibility by reflecting upon current diagnoses of our 'technological situation' by some exemplary post-operaist Marxists from a Stieglerian, pharmacological perspective.

The Impact of Conservation Management on the Community Composition of Multiple Organism Groups in Eutrophic Interconnected Man-Made Ponds

Ponds throughout the world are subjected to a variety of management measures for purposes of biodiversity conservation. Current conservation efforts typically comprise a combination of multiple measures that directly and indirectly impact a wide range of organism groups. Knowledge of the relative impact of individual measures on different taxonomic groups is important for the development of effective conservation programs. We conducted a field study of 28 man-made ponds, representing four management types differing in the frequency of periodic pond drainage and the intensity of fish stock management. We disentangled the relative importance of direct and indirect effects of pond management measures on the community composition of phytoplankton, zooplankton, aquatic macro-invertebrates, submerged and emergent vascular plants. With the exception of phytoplankton, pond management had strong effects on the community composition of all investigated biota. Whether management affected communities directly or indirectly through its impact on fish communities or local environmental conditions in the pond varied between organism groups. Overall, the impact of pond drainage regime and fish community characteristics on the community composition of target organism groups were more important than local environmental conditions. The majority of taxa were negatively associated with fish density, whereas multiple emergent plant species and several taxa of aquatic macro-invertebrates were positively affected by increased drainage frequency. The effects of fish community and drainage tended to be largely independent. The present study indicates that pond drainage is an important element for biodiversity conservation in eutrophicated shallow and interconnected man-made ponds.

Ultrasound study of FeCr2S4 in high magnetic fields

We report on ultrasound studies of FeCr2S4 in static and pulsed magnetic fields exhibiting an orbital-order transition at 9 K. A longitudinal acoustic mode exhibits distinct features in the phase space of temperature and magnetic field due to magnetic and structural transformations. Pulsed-field measurements show significant differences in the sound velocity below and above the orbital-ordering transition as well as the spin-reorientation transition at 60 K. Our results indicate a reduction of the magnetocrystalline anisotropy on entering the orbitally ordered phase.

An ecosystem service approach to support integrated pond management: a case study using Bayesian belief networks--highlighting opportunities and risks

Freshwater ponds deliver a broad range of ecosystem services (ESS). Taking into account this broad range of services to attain cost-effective ESS delivery is an important challenge facing integrated pond management. To assess the strengths and weaknesses of an ESS approach to support decisions in integrated pond management, we applied it on a small case study in Flanders, Belgium. A Bayesian belief network model was developed to assess ESS delivery under three alternative pond management scenarios: intensive fish farming (IFF), extensive fish farming (EFF) and nature conservation management (NCM). A probabilistic cost-benefit analysis was performed that includes both costs associated with pond management practices and benefits associated with ESS delivery. Whether or not a particular ESS is included in the analysis affects the identification of the most preferable management scenario by the model. Assessing the delivery of a more complete set of ecosystem services tends to shift the results away from intensive management to more biodiversity-oriented management scenarios. The proposed methodology illustrates the potential of Bayesian belief networks. BBNs facilitate knowledge integration and their modular nature encourages future model expansion to more encompassing sets of services. Yet, we also illustrate the key weaknesses of such exercises, being that the choice whether or not to include a particular ecosystem service may determine the suggested optimal management practice.

Magnetic, structural, and electronic properties of the multiferroic compound FeTe₂O₅Br with geometrical frustration

We report electron spin resonance (ESR), Raman scattering, and interband absorption measurements of the multiferroic FeTe₂O₅Br with two successive magnetic transitions at T(N1) = 11.0 K and T(N2) = 10.5 K. ESR measurements show all characteristics of a low-dimensional frustrated magnet: (i) the appearance of an antiferromagnetic resonance (AFMR) mode at 40 K, a much higher temperature than T(N1), and (ii) a weaker temperature dependence of the AFMR linewidth than in classical magnets, ΔH(pp)(T) ∝ T(n) with n = 2.2-2.3. Raman spectra at ambient pressure show a large variation of phonon intensities with temperature while there are no appreciable changes in phonon numbers and frequencies. This demonstrates the significant role of the polarizable Te⁴⁺ lone pairs in inducing multiferroicity. Under pressure at P = 2.12-3.04 GPa Raman spectra undergo drastic changes and absorption spectra exhibit an abrupt drop of a band gap. This evidences a pressure-induced structural transition related to changes of the electronic states at high pressures.

How to maximally support local and regional biodiversity in applied conservation? Insights from pond management

Biodiversity and nature values in anthropogenic landscapes often depend on land use practices and management. Evaluations of the association between management and biodiversity remain, however, comparatively scarce, especially in aquatic systems. Furthermore, studies also tend to focus on a limited set of organism groups at the local scale, whereas a multi-group approach at the landscape scale is to be preferred. This study aims to investigate the effect of pond management on the diversity of multiple aquatic organism groups (e.g. phytoplankton, zooplankton, several groups of macro-invertebrates, submerged and emergent macrophytes) at local and regional spatial scales. For this purpose, we performed a field study of 39 shallow man-made ponds representing five different management types. Our results indicate that fish stock management and periodic pond drainage are crucial drivers of pond biodiversity. Furthermore, this study provides insight in how the management of eutrophied ponds can contribute to aquatic biodiversity. A combination of regular draining of ponds with efforts to keep ponds free of fish seems to be highly beneficial for the biodiversity of many groups of aquatic organisms at local and regional scales. Regular draining combined with a stocking of fish at low biomass is also preferable to infrequent draining and lack of fish stock control. These insights are essential for the development of conservation programs that aim long-term maintenance of regional biodiversity in pond areas across Europe.

Cutaneous neosporosis in an adult dog in Belgium

A twelve-year-old female spayed Greyhound was presented with ulcerative nodular lesions,generalized weakness and pain. At the time of presentation, the dog was receiving prednisolonefor a presumptive diagnosis of cervical discus hernia. Fine needle aspiration of the nodular lesionsdemonstrated protozoal tachyzoites. Immunohistochemistry confi rmed the diagnosis of Neosporacaninum infection. Clindamycin therapy, together with the withdrawal of immunosuppressivemedication, resulted in complete remission. This report documents the fi rst case of cutaneousneosporosis in Belgium.

Evidence for dimer crystal melting in the frustrated spin-ladder system BiCu2PO6

In the spin ladder compound BiCu(2)PO(6), there exists a decisive dynamics of spin excitations that we classify and characterize using inelastic light scattering. We observe an interladder singlet bound mode at 24  cm(-1) and two intraladder bound states at 62 and 108  cm(-1) in the leg (bb) and the rung (cc) polarization as well as a broad triplon continuum extending from 36  cm(-1) to 700  cm(-1). Though isolated spin ladder physics can roughly account for the observed excitations at high energies, frustration and interladder interactions need to be considered to fully describe the spectral distribution and scattering selection rules at low and intermediate energies. In addition, we attribute the rich spectrum of singlet bound modes to a melting of a dimer crystal. Our study provides evidence for a Z(2) quantum phase transition from a dimer to a resonating valence bond state driven by singlet fluctuations.

Long-wavelength helimagnetic order and skyrmion lattice phase in Cu2OSeO3

We report a long-wavelength helimagnetic superstructure in bulk samples of the ferrimagnetic insulator Cu2OSeO3. The magnetic phase diagram associated with the helimagnetic modulation inferred from small-angle neutron scattering and magnetization measurements includes a skyrmion lattice phase and is strongly reminiscent of MnSi, FeGe, and Fe(1-x)Co(x)Si, i.e., binary isostructural siblings of Cu2OSeO3 that order helimagnetically. The temperature dependence of the specific heat of Cu2OSeO3 is characteristic of nearly critical spin fluctuations at the helimagnetic transition. This provides putative evidence for effective spin currents as the origin of enhancements of the magnetodielectric response instead of atomic displacements considered so far.

The spin dynamics in distorted kagome lattices: a comparative Raman study

Despite the conceptional importance of realizing spin liquids in solid states only few compounds are known. On the other hand the effect of lattice distortions and anisotropies on the magnetic exchange topology and the fluctuation spectrum is an interesting problem. We compare the excitation spectra of the two s = 1/2 kagome lattice compounds, volborthite and vesignieite, using Raman scattering. We demonstrate that even small modifications of the crystal structure may have a huge effect on the phonon spectrum and low-temperature properties.

Coherent manipulation of electron spins in the {Cu3} spin triangle complex impregnated in nanoporous silicon

We report on coherent manipulation of electron spins in an antiferromagnetically coupled spin triangle {Cu3-X} (X=As, Sb) impregnated in freestanding nanoporous silicon (NS) by using 240 GHz microwave pulses. Rabi oscillations are observed and the spin coherence time is found to be T(2)=1066 ns at 1.5 K. This demonstrates that the {Cu3-X}:NS hybrid material provides a promising scheme for implementing spin-based quantum gates. By measuring the spin relaxation times of samples with different symmetries and environments we give evidence that a spin chirality is the main decoherence source of spin triangle molecules.

Magnetostructural transitions in a frustrated magnet at high fields

Ultrasound and magnetization studies of bond-frustrated ZnCr(2)S(4) spinel are performed in static magnetic fields up to 18 T and in pulsed fields up to 62 T. At temperatures below the antiferromagnetic transition at T(N1)≈14  K, the sound velocity as a function of the magnetic field reveals a sequence of steps followed by plateaus indicating a succession of crystallographic structures with constant stiffness. At the same time, the magnetization evolves continuously with a field up to full magnetic polarization without any plateaus in contrast to geometrically frustrated chromium oxide spinels. The observed high-field magnetostructural states are discussed within a H-T phase diagram taking into account the field and temperature evolution of three coexisting spin structures and subsequent lattice transformations induced by the magnetic field.

Magnetic phase diagram of multiferroic MnWO4 probed by ultrasound

The magnetic phase diagram of multiferroic MnWO(4) is studied in magnetic fields up to 60 T using sound velocity and sound attenuation measurements. Anomalies are observed at temperatures T(N1) = 7.6 K, T(N2) = 12.6 K and T(N3) = 13.6 K that separate commensurate antiferromagnetic (AF1) to helical AF2 and commensurate AF3 to paramagnetic phases, respectively. The anomalies are significantly different and shed light on the spin-phonon coupling and evolution of the various order parameters in this multiferroic material. For temperatures below T(N2) pronounced field hysteresis effects are also observed in the sound velocity, indicating field-induced transformations. In the temperature dependence of the attenuation we observe anomalies distinctively different from the usual maxima related to relaxation effects. They are attributed to the combination of dispersion effects due to domain walls and the discontinuously changing sound velocity. In total, six different magnetic phases, at various temperatures and fields including a novel high-field phase, are revealed and analyzed.

Self-energy effects and electron-phonon coupling in Fe-As superconductors

Doping and temperature dependent studies of optical phonon modes in Fe-122 pnictides are performed using Raman scattering experiments and compared with model calculations to elucidate the role of electron-phonon and spin-phonon interaction in this family of compounds. The frequency and linewidth of the B(1g) mode at around 210 cm(-1) is highlighted as appreciable anomalies at the superconducting and spin density wave transitions are observed that strongly depend on composition. We give estimates of the electron-phonon coupling related to this renormalization and calculate the phonon self-energy on the basis of a four-band model comparing different symmetries of the order parameters. In addition, we observe a pronounced quasi-elastic Raman response for the undoped compound, suggesting persisting magnetic fluctuations in the spin density wave state.

Microscopic evidence of spin state order and spin state phase separation in layered cobaltites RBaCo2O5.5 with R=Y, Tb, Dy, and Ho

We report muon-spin relaxation measurements on the magnetic structures of RBaCo2O(5.5) with R=Y, Tb, Dy, and Ho. Three different phases, one ferrimagnetic and two antiferromagnetic, are identified below 300 K. They consist of different ordered spin state arrangements of high-, intermediate-, and low-spin Co3+ of CoO6 octahedra. Phase separation into well separated regions with different spin state order is observed in the antiferromagnetic phases. The unusual strongly anisotropic magnetoresistance and its onset at the FM-AFM phase boundary is explained.

Approaching the ground state of the kagomé antiferromagnet

Y0.5Ca0.5BaCo4O7 contains kagomé layers of Co ions, whose spins are strongly coupled, with a Curie-Weiss temperature of -2200 K. At low temperature, T=1.2 K, our diffuse neutron scattering study with polarization analysis reveals characteristic spin correlations close to a predicted two-dimensional coplanar ground state with staggered chirality. The absence of three-dimensional long-range antiferromagnetic order indicates negligible coupling between the kagomé layers. The scattering intensities are consistent with high spin S=3/2 states of Co2+ in the kagomé layers and low spin S=0 states for Co3+ ions on interlayer sites. Our observations agree with previous Monte Carlo simulations indicating a ground state of effectively short range, staggered chiral spin order.

Anomalous electronic Raman scattering in NaxCoO2.yH2O

Raman scattering experiments on NaxCoO2.yH2O single crystals show a broad electronic continuum with a pronounced peak around 100 cm(-1) and a cutoff at approximately 560 cm(-1) over a wide range of doping levels. The electronic Raman spectra in superconducting and nonsuperconducting samples are similar at room temperature, but evolve in markedly different ways with decreasing temperature. For superconducting samples, the low-energy spectral weight is depleted upon cooling below T* approximately 150 K, indicating the opening of a pseudogap that is not present in nonsuperconducting materials. Weak additional phonon modes observed below T* suggest that the pseudogap is associated with charge ordering.

Sound attenuation study on the bose-Einstein condensation of magnons in TlCuCl3

We investigate experimentally and theoretically sound attenuation in the quantum spin system TlCuCl3 in magnetic fields at low temperatures. Near the point of Bose-Einstein condensation of magnons a sharp peak in the sound attenuation is observed. The peak demonstrates a hysteresis as a function of the magnetic field pointing to a first-order contribution to the transition. The sound damping has a Drude-like form arising as a result of hard-core magnon-magnon collisions. The strength of the coupling between lattice and magnons is estimated from the experimental data. The puzzling relationship between the transition temperature and the concentration of magnons is explained by their "relativistic" dispersion.

Evidence for an unconventional magnetic instability in the spin-tetrahedra system Cu(2)Te(2)O(5)Br(2)

Thermodynamic experiments as well as Raman scattering have been used to study the magnetic instabilities in the spin-tetrahedra systems Cu(2)Te(2)O(5)X(2), X = Cl and Br. While the phase transition observed in the Cl system at T(N) = 18.2 K is consistent with 3D antiferromagnetic ordering, the phase transition at T(o) = 11.4 K in the Br system has several unusual features. We propose an explanation in terms of weakly coupled tetrahedra with a singlet-triplet gap and low-lying singlets.

Experimental evaluation of a cell module for hybrid liver support

Aim of the study was to evaluate a hybrid liver support system in a porcine model of acute liver failure, after hepatectomy. Pigs with a body weight of 70+/-18 kg underwent total hepatectomy and porto-cavo-caval shunting as well as ligation of the bile duct and the hepatic artery. Control animals were connected to the system (including capillary membrane plasma separation) containing a four compartment bioreactor with integral oxygenation and decentralized mass exchange but without liver cells. The treatment group received hybrid liver support with the same system including 370+/-42 g primary isolated porcine parenchymal liver cells in co-culture with hepatocyte nursing cells, tissue engineered to liver- like structures at high density. Treatment started after complete recovery from anesthesia and was performed continuously. A positive influence on peripheral vascular resistance and a reduced need of catecholamine dosage was observed in the treatment group. Hybrid liver support with a cell module upscaled for clinical application significantly prolonged survival time in animals after hepatectomy with the longest survival being 26 hours in the control group an 57 hours in the treatment group.

Treatment of the symptoms of schizophrenia: a combined analysis of double-blind studies comparing risperidone with haloperidol and other antipsychotic agents

Combined data on efficacy were available from 12 double-blind short-term (maximum 8 weeks) trials comparing risperidone and other antipsychotics in patients with chronic schizophrenia. Patients received risperidone (n = 1056) or other antipsychotics (n = 703). Haloperidol (n = 473) was the most frequently prescribed other antipsychotic. Efficacy assessments include the Positive and Negative Syndrome Scale (PANSS) total, subscale (positive symptoms, negative symptoms and general psychopathology), cluster (cognitive and affective symptoms) and item (anxiety and hostility) scores. At endpoint, the mean decrease from baseline in PANSS total scores was significantly greater for patients receiving risperidone (-20.9) than other antipsychotics (-16.2; P < 0.001), or the subset receiving haloperidol (-14.3; P < 0.001). Risperidone-treated patients showed a significantly greater decrease in the positive (P < 0.01), negative (P < 0.05) and general psychopathology (P < 0.001) scores than patients receiving other antipsychotics or haloperidol. Scores for cognition, affective symptoms, anxiety and hostility each improved significantly (P < 0.05) more for patients receiving risperidone than those receiving other antipsychotics or haloperidol. Efficacy data on patients with an acute exacerbation were available from seven trials (risperidone n = 372, other antipsychotics n = 285, including haloperidol n = 120). At endpoint, the mean decrease from baseline in PANSS total scores was significantly greater for patients receiving risperidone (-24.7) than other antipsychotics (-19.8, P < 0.01) including haloperidol (-19.8, P < 0.05). Risperidone-treated patients also showed a greater decrease in positive symptom scores (-7.8) than those receiving other antipsychotics (-6.3; P < 0.01) or haloperidol (-7.1). A > or = 20% reduction in PANSS total score with risperidone, haloperidol and other antipsychotics was achieved by 65.9%, 54.3% and 54.9%, respectively; a > or = 30% PANSS reduction by 54.0%, 46.6% and 46.5% of patients, respectively; and a > or = 40% reduction by 43.8%, 33.7% and 34.4% of patients, respectively. These findings are consistent with earlier findings that show risperidone is more efficacious than haloperidol for reducing the symptoms of schizophrenia.

A qualitative assessment of the neurological safety of antipsychotic drugs; an analysis of a risperidone database

BACKGROUND

Neurological side effects of antipsychotic agents limit the use of these drugs, and development of newer antipsychotic agents has been focused on a reduced risk of extrapyramidal symptoms (EPS) as well as effective symptom control.

METHODS

A qualitative analysis of EPS was performed using Extrapyramidal Symptom Rating Scale (ESRS) data from 11 double-blind risperidone trials. An ESRS factor analysis and maximum changes in ESRS scores were compared for the risperidone, haloperidol, and placebo groups.

RESULTS

The factor analysis revealed five factors. Between-group comparisons showed no differences between placebo and 1 to 2 mg/day-risperidone groups. Parkinsonism, tremor, akathisia, and sialorrhea were more likely to occur with haloperidol than with placebo or risperidone at 1 to 6 mg/day. Similar results were noted by maximum changes in ESRS scores. At risperidone doses of more than 8 mg/day, acute EPS severity lay between that of the placebo and haloperidol groups. The severity of tardive dyskinesia was greater in patients receiving placebo than in those receiving either active treatment.

CONCLUSIONS

As the results described above were derived from a post hoc analysis of an existing database, conclusions must remain tentative. To provide more definitive answers, EPS assessments in future studies should be refined to more accurately predict the type of EPS expected with a given agent in clinical practice.

Xenogeneic ex vivo hemoperfusion of rhesus monkey livers with human blood

In order to copy the clinical situation of concordant xenotransplantation, Rhesus Monkey livers were hemoperfused with human blood. Changes of immunological (TNFalpha, IL-1beta, IL-2, IL-2R, IL-6, IFNgamma, TXB2, 6kPGF1alpha, sICAM-1, sELAM-1, sHLA-I-Ag) and pathophysiological (GOT, GPT, LDH, CK) parameters were followed. Our experiment proves that all phenomena start in the first hour of xenogeneic blood circulation. Xenogeneic rejection in our concordant system is surprisingly severe. Preformed natural antibodies only cannot be the reason of such a damage. We think that beside other important immunological mechanisms, humoral mediators play a considerable role at the beginning of a xenogeneic rejection.

Effects of risperidone on affective symptoms in patients with schizophrenia

The effects of risperidone on affective symptoms were determined by an analysis of pooled data from six double-blind trials of risperidone versus haloperidol in 1254 patients with chronic schizophrenia. Symptoms indicating mania were assessed by the Positive and Negative Syndrome Scale (PANSS) excitement and grandiosity items and by the excited cluster (excitement, hostility, uncooperativeness, and poor impulse control); anxious / depressive symptoms were assessed by the PANSS anxious / depressive cluster (somatic concern, anxiety, guilt feelings, and depression). Mean change scores from baseline to endpoint were compared in patients receiving risperidone, haloperidol or placebo by analysis of variance with factors for trial and baseline score included in the model. In all patients, change scores on excitement and grandiosity items and excited and anxious / depressive clusters were significantly greater for risperidone than for haloperidol or placebo. Dropouts due to inefficacy were less frequent with risperidone (5 of 59; 8%) than with haloperidol (7 of 38; 18%) or placebo (8 of 10; 80%). In patients with anxious / depressive symptoms at baseline (anxiety / depression cluster score > or = the median), anxiety / depression scores decreased significantly more with risperidone than with haloperidol, and symptom reduction occurred faster with risperidone. These results are consistent with previous reports and suggest that risperidone is more efficacious than haloperidol for affective symptoms in patients with schizophrenia.

Collective singlet excitations and evolution of raman spectral weights in the 2D spin dimer compound SrCu2(BO3)(2)

Raman light scattering of the two-dimensional quantum spin system SrCu2(BO3)(2) shows a rich structure in the magnetic excitation spectrum, including several well-defined bound state modes at low temperature, and a scattering continuum and quasielastic light scattering contributions at high temperature. The key to the understanding of the unique features of SrCu2(BO3)(2) is the presence of strong interactions between well-localized triplet excitations in the network of orthogonal spin dimers realized in this compound.

Stripe conductivity in La1.775Sr0.225NiO4

We report Raman light-scattering and optical conductivity measurements on a single crystal of La1.775Sr0.225NiO4 which exhibits incommensurate charge-stripe order. The extra phonon peaks induced by stripe order can be understood in terms of the energies of phonons that occur at the charge-order wave vector Q(c). A strong Fano antiresonance for a Ni-O bond-stretching mode provides clear evidence for finite dynamical conductivity within the charge stripes.

Periplakin and envoplakin are target antigens in canine and human paraneoplastic pemphigus

BACKGROUND

On the basis of clinical and histopathologic similarities to human paraneoplastic pemphigus (PNP), we recently identified the first case of PNP in a nonhuman species, the dog.

OBJECTIVE

To determine a similar pathogenesis in both species, the present study aimed to define whether common antigens are targeted in dog and man.

METHODS

Canine and human PNP sera were used in parallel to immunoprecipitate 14C-labeled human keratinocyte antigens. The immunoreactive proteins were then identified by immunoprecipitation of canine keratinocyte extracts with specific antibodies to the antiplakin family members follwed by immunoblot analysis using canine and human PNP sera.

RESULTS

Protein bands of 210, 190, 170, and 130 kd were identified in dogs and humans. In both species, envoplakin and periplakin were demonstrated as antigens. Anti-desmoglein 3 antibodies could not be demonstrated in canine PNP, but in human PNP.

CONCLUSION

These results demonstrate that canine PNP closely correlates to the human counterpart and may therefore represent an excellent model for the human disease.