Commissioning of the novel Continuous Angle Multi-energy Analysis spectrometer at the Paul Scherrer Institut

We report on the commissioning results of the cold neutron multiplexing secondary spectrometer CAMEA (Continuous Angle Multi-Energy Analysis) at the Swiss Spallation Neutron Source at the Paul Scherrer Institut, Switzerland. CAMEA is optimized for efficient data acquisition of scattered neutrons in the horizontal scattering plane, allowing for detailed and rapid mapping of low-energy excitations under extreme sample environment conditions.

Agroecology landscapes

CONTEXT

Agroecology combines agronomic and ecological concepts. It relies on the enhancement of biodiversity and related ecosystem services to support agricultural production. It is dependent on biological interactions for the design and management of agricultural systems in agricultural landscapes.

OBJECTIVES

We review the role of landscape ecology to understand and promote biodiversity, pest regulation and crop pollination for the designing of "agroecology landscapes". We illustrate the use of landscape ecological methods for supporting agroforestry systems as an example of agroecological development, and we propose pathways to implement agroecology at landscape scale.

METHODS

The state of the art of how landscape ecology contributes to agroecology development is summarized based on a literature review.

RESULTS

Agroecology requires thinking beyond the field scale to consider the positioning, quality and connectivity of fields and semi-natural habitats at larger spatial scales. The spatial and temporal organisation of semi-natural elements and the crop mosaic interact. Understanding this interaction is the pre-requisite for promoting patterns and mechanisms that foster biodiversity and ecosystem service provision. Promoting agroecological practices beyond individual farm borders can be rooted in a bottom-up approach from agroecological lighthouse farms to farm networks to amplify agroecology adoption at the landscape scale.

CONCLUSIONS

Achieving agricultural landscapes composed of fields and farms following agroecological management requires understanding of biodiversity patterns, biological interactions and mechanisms that determine and boost ecosystem functioning to improve services at landscape scale, involving farmers in a bottom-up and context-specific approach.

Confinement and inhomogeneous broadening effects in the quantum oscillatory magnetization of quantum dot ensembles

We report on the magnetization of ensembles of etched quantum dots with a lateral diameter of 460 nm, which we prepared from InGaAs/InP heterostructures. The quantum dots exhibit 1/B-periodic de-Haas-van-Alphen-type oscillations in the magnetization M(B) for external magnetic fields B  >  2 T, measured by torque magnetometry at 0.3 K. We compare the experimental data to model calculations assuming different confinement potentials and including ensemble broadening effects. The comparison shows that a hard wall potential with an edge depletion width of 100 nm explains the magnetic behavior. Beating patterns induced by Rashba spin-orbit interaction (SOI) as measured in unpatterned and nanopatterned InGaAs/InP heterostructures are not observed for the quantum dots. From our model we predict that signatures of SOI in the magnetization could be observed in larger dots in tilted magnetic fields.

Relating costs to the user value of farmland biodiversity measurements

The impact of agricultural management on global biodiversity highlights the need for farm-scale monitoring programmes capable of determining the performance of agriculture practices. Yet the identification of appropriate indicators is a challenging process and one that involves considering a number of different aspects and requirements. Besides the attention given to scientific effectiveness, relevant but less studied issues related to biodiversity measurements include the economic feasibility of monitoring programmes and the relevance of indicators for different end-users. In this paper, we combine an analytic assessment of costs and a stakeholder-based evaluation of the usefulness of a set of biodiversity-related parameters (habitat mapping, vegetation, bees, earthworms, spiders, and a farmer questionnaire) tested for scientific consistency in 12 European case studies and on more than 14,000 ha of farmland. The results point to the possibility of meeting the expectations of different end-users (administrators, farmers and consumers) with a common indicator set. Combining costs and usefulness also suggests the possibility of designing more efficient monitoring approaches involving private agencies and networks of volunteers and farmers for the field data collection at different stages of a monitoring programme. Although complex, such an approach would make it possible to enhance the effectiveness of available funds for farmland biodiversity monitoring.

Architecture of the RNA polymerase II-Mediator core initiation complex

The conserved co-activator complex Mediator enables regulated transcription initiation by RNA polymerase (Pol) II. Here we reconstitute an active 15-subunit core Mediator (cMed) comprising all essential Mediator subunits from Saccharomyces cerevisiae. The cryo-electron microscopic structure of cMed bound to a core initiation complex was determined at 9.7 Å resolution. cMed binds Pol II around the Rpb4-Rpb7 stalk near the carboxy-terminal domain (CTD). The Mediator head module binds the Pol II dock and the TFIIB ribbon and stabilizes the initiation complex. The Mediator middle module extends to the Pol II foot with a 'plank' that may influence polymerase conformation. The Mediator subunit Med14 forms a 'beam' between the head and middle modules and connects to the tail module that is predicted to bind transcription activators located on upstream DNA. The Mediator 'arm' and 'hook' domains contribute to a 'cradle' that may position the CTD and TFIIH kinase to stimulate Pol II phosphorylation.

Prediction uncertainty of environmental change effects on temperate European biodiversity

Observed patterns of species richness at landscape scale (gamma diversity) cannot always be attributed to a specific set of explanatory variables, but rather different alternative explanatory statistical models of similar quality may exist. Therefore predictions of the effects of environmental change (such as in climate or land cover) on biodiversity may differ considerably, depending on the chosen set of explanatory variables. Here we use multimodel prediction to evaluate effects of climate, land-use intensity and landscape structure on species richness in each of seven groups of organisms (plants, birds, spiders, wild bees, ground beetles, true bugs and hoverflies) in temperate Europe. We contrast this approach with traditional best-model predictions, which we show, using cross-validation, to have inferior prediction accuracy. Multimodel inference changed the importance of some environmental variables in comparison with the best model, and accordingly gave deviating predictions for environmental change effects. Overall, prediction uncertainty for the multimodel approach was only slightly higher than that of the best model, and absolute changes in predicted species richness were also comparable. Richness predictions varied generally more for the impact of climate change than for land-use change at the coarse scale of our study. Overall, our study indicates that the uncertainty introduced to environmental change predictions through uncertainty in model selection both qualitatively and quantitatively affects species richness projections.

Regulation of enterocyte apoptosis by acyl-CoA synthetase 5 splicing

BACKGROUND AND AIMS

The constant renewal of enterocytes along the crypt-villus axis (CVA) of human small intestine is due to cell-inherent changes resulting in the apoptotic cell death of senescent enterocytes. The aim of the present study was to examine underlying molecular mechanisms of the cell death at the villus tip.

METHODS

Characterization of human acyl-coenzyme A (CoA) synthetase 5 (ACSL5) was performed by cloning, recombinant protein expression, biochemical approaches, and several functional and in situ analyses.

RESULTS

Our data show that different amounts of acyl-CoA synthetase 5-full length (ACSL5-fl) and a so far unknown splice variant lacking exon 20 (ACSL5-Delta 20) are found in human enterocytes. In contrast with the splice variant ACSL5-Delta 20, recombinant and purified ACSL5-fl protein is active at a highly alkaline pH. Over expression of ACSL5-fl protein is associated with a decrease of the anti-apoptotic FLIP protein in a ceramide-dependent manner and an increased cell-surface expression of the death receptor TRAIL-R1. Expression analyses revealed that the ACSL5-fl/ACSL5-Delta 20 ratio increases along the CVA, thereby sensitizing ACSL5-fl-dominated cells at the villus tip to the death ligand TRAIL, which is corroborated by functional studies with human small intestinal mucosal samples and an immortalized human small intestinal cell line.

CONCLUSIONS

Our results suggest an ACSL5-dependent regulatory mechanism that contributes to the cellular renewal along the CVA in human small intestine. Deregulation of the ACSL5-fl/ACSL5-Delta 20 homeostasis in the maturation and shedding of cells along the CVA might also be of relevance for the development of intestinal neoplasia.

Mixed biodiversity benefits of agri-environment schemes in five European countries

Agri-environment schemes are an increasingly important tool for the maintenance and restoration of farmland biodiversity in Europe but their ecological effects are poorly known. Scheme design is partly based on non-ecological considerations and poses important restrictions on evaluation studies. We describe a robust approach to evaluate agri-environment schemes and use it to evaluate the biodiversity effects of agri-environment schemes in five European countries. We compared species density of vascular plants, birds, bees, grasshoppers and crickets, and spiders on 202 paired fields, one with an agri-environment scheme, the other conventionally managed. In all countries, agri-environment schemes had marginal to moderately positive effects on biodiversity. However, uncommon species benefited in only two of five countries and species listed in Red Data Books rarely benefited from agri-environment schemes. Scheme objectives may need to differentiate between biodiversity of common species that can be enhanced with relatively simple modifications in farming practices and diversity or abundance of endangered species which require more elaborate conservation measures.

Optical phase locked loop for transparent inter-satellite communications

A novel type of optical phase locked loop (OPLL), optimized for homodyne inter-satellite communication, is presented. The loop employs a conventional 180? 3 dB optical hybrid and an AC-coupled balanced front end. No residual carrier transmission is required for phase locking. The loop accepts analog as well as digital data and various modulation formats. The only requirement to the transmitted user signal is a constant envelope. Phase error extraction occurs through applying a small sinusoidal local oscillator (LO) phase disturbance, while measuring its impact on the power of the baseband output signal. First experimental results indicate a receiver sensitivity of 36 photons/bit (-55.7 dBm) for a BER of 10 ;-9, when transmitting a PRBS-31 signal at a data rate of 400 Mbit/s. The system setup employs diode-pumped Nd:YAG lasers at a wavelength of 1.06 mum.

Supplementing land-use statistics with landscape metrics: some methodological considerations

Landscape monitoring usually relies on land-use statistics which reflect the share of land-sue/land cover types. In order to understand the functioning of landscapes, landscape pattern must be considered as well. Indicators which address the spatial configuration of landscapes are therefore needed. The suitability of landscape metrics, which are computed from the type, geometry and arrangement of patches, is examined. Two case studies in a surface mining region show that landscape metrics capture landscape structure but are highly dependent on the data model and on the methods of data analysis. For landscape metrics to become part of policy-relevant sets of environmental indicators, standardised procedures for their computation from remote sensing images must be developed.

Landscape metrics for assessment of landscape destruction and rehabilitation

This investigation tested the usefulness of geometry-based landscape metrics for monitoring landscapes in a heavily disturbed environment. Research was carried out in a 75 sq km study area in Saxony, eastern Germany, where the landscape has been affected by surface mining and agricultural intensification. Landscape metrics were calculated from digital maps (1912, 1944, 1973, 1989) for the entire study area and for subregions (river valleys, plains), which were defined using the original geology and topography of the region. Correlation and factor analyses were used to select a set of landscape metrics suitable for landscape monitoring. Little land-use change occurred in the first half of the century, but political decisions and technological developments led to considerable change later. Metrics showed a similar pattern with almost no change between 1912 and 1944, but dramatic changes after 1944. Nonparametric statistical methods were used to test whether metrics differed between river valleys and plains. Significant differences in the metrics for these regions were found in the early maps (1912, 1944), but these differences were not significant in 1973 or 1989. These findings indicate that anthropogenic influences created a more home geneous landscape.

Chronic liver disease in children on long-term parenteral nutrition

Use of long-term total parenteral nutrition (TPN) is often presumed to be associated with serious hepatic dysfunction. In this retrospective study, we reviewed the complete charts of patients who had received TPN for more than 2.5 years, starting in infancy or childhood, for evidence of liver dysfunction. There were 16 male and 10 female patients with a total of 254.5 patient years on TPN. Seventeen patients have been on TPN since birth or early infancy. Thirteen of 26 patients derive > or = 90% of their calorie intake from TPN. Six patients had hepatomegaly; two of them also had splenomegaly. Twenty-one patients had normal transaminases, nine have had past episodes of raised enzymes ranging from 2.5 to 7.5 times normal. Seventeen patients always had normal bilirubin levels, five had past episodes of hyperbilirubinaemia, while four patients had persistently raised bilirubin levels (range 1.5-20.7 g/dl). Alkaline phosphatase was normal for age in all patients except two. Hepatic synthetic function, as measured by albumin, pre-albumin levels and prothrombin time, was within the normal range in all patients except one. Liver biopsies were performed in eight patients. Two biopsies showed cirrhosis, one showed chronic active hepatitis (CAH) with cholestasis, two patients had fibrosis, one showed cholestasis and two biopsies were normal. One patient with cirrhosis and one with CAH were positive for hepatitis C antibody. Another asymptomatic patient was positive for hepatitis B. Only the patient with CAH had hepatic decompensation. We conclude that clinical hepatic failure is uncommon in our group of patients on long-term TPN for 2.5 years or more. Cirrhosis and fibrosis, when found, could not be solely attributed to TPN.

Catheter-related infections associated with home parenteral nutrition and predictive factors for the need for catheter removal in their treatment

The inpatient and outpatient records were reviewed for 527 patients, including 138 children, who were discharged on home total parenteral nutrition and followed by the University of California, Los Angeles, home total parenteral nutrition service for a minimum of 1 week between April 1973 and October 1991. The total follow-up time was 1154 patient years; the median follow-up time was 206 days (range 7 to 6344 days). Thirty-six patients were followed for more than 10 years (median 12.7 years). Three hundred fifteen adults (but only four children) were never infected. A total of 427 catheter-related infections occurred, giving an overall infection rate of 0.37 per patient year (0.51 per patient year in children and 0.28 per patient year in patients followed for more than 10 years). Seventy percent of the infections overall were sepsis (0.26 per patient year); of those, 17% were exit site (0.06 per patient year), and 2% were tunnel (0.01 per patient year) infections. In children, 67% of the infections were sepsis (0.37 per patient year) and 24% were exit site (0.13 per patient year). Fifty-four different organisms were responsible, and 12% of the infections were polymicrobial in origin. Sixty percent of sepsis in all patients was caused by Gram-negative organisms (44% of the catheters were removed). Forty-three percent of sepsis in children was caused by Gram-negative organisms. Twenty-six percent of sepsis in all patients was caused by Gram-positive organisms (40% of the catheters were removed). Thirty-six percent of sepsis in children was caused by Gram-positive organisms.(ABSTRACT TRUNCATED AT 250 WORDS)

The large type II 70-kDa keratin of mouse epidermis is the ortholog of human keratin K2e

The basic keratin pattern of mammalian epidermis consists of the basal keratin pair K5/K14 and the differentiation-specific keratin pair K1/K10. Distinct skin sites of the adult mouse, i.e., ear, sole of the foot, and interscale regions of tail skin, express an additional, type II 70-kilodalton (kDa) keratin without a defined new type I partner in suprabasal epidermal cells. Until now, the question whether this large keratin is specific for the mouse (or related small rodents) or whether orthologous keratins exist in other species has not yet been answered. In the present study, we have determined the full-length amino acid sequence of the 70-kDa keratin. The keratin comprises 707 amino acid residues and has a calculated molecular weight of 70,976.70 Da. From the structural point of view, the 70-kDa keratin is remarkable in that more than half of both the V1 and V2 subdomains of its non alpha-helical head and tail portions consist of different glycine-rich peptide motifs that are configured consecutively at least two times and as much as seven times in tandem. By means of sequence comparisons and phylogenetic investigations, we show that the 70-kDa keratin represents the murine ortholog of the human 65-kDa keratin K2e, whose nature as a genuine keratin has recently been demonstrated. The unusually large size difference of 5 kDa between MK2e and HK2e is due mainly to a different duplication rate of the glycine-rich peptide motifs in the respective V subdomains of the orthologous keratins. We discuss the properties of these highly specialized keratins, which in both species define locally restricted epidermal keratin phenotypes, and compare them with other orthologous keratins that belong to the basic epidermal keratin pattern.

Effects of isolation, handling and novelty on the pituitary--adrenal response in the mouse

Male Swiss strain mice were individually- or group-housed for four weeks. Basal corticosterone levels did not differ with the type of housing, providing no support for the suggestion that the condition of the individually-housed mouse is stressful. Plasma corticosterone levels also were determined for mice which had been either left undisturbed or exposed to new cages which differed from their home cages by varying degrees. There were elevations in mean plasma corticosterone levels corresponding to the degree of difference between the home cage and the new cage. This finding supports the suggestion that changes in 11-OHCS levels are sensitive measures of environmental changes. Mice forced to remain in novel places exhibited higher plasma corticoid concentrations than animals which were given the opportunity to move freely between familiar and novel places. Corticoid values, as well as neurophysiological and behavioral responses, suggested that the stress induced by forced exploration might be due to the fact that animals are prevented from freely regulating their exposure to novel places rather than to novelty per se.

[The prevention of chickenpox in high risk children. Comparison of the effectiveness of specific immunoglobulins and of defibrinated convalescent plasma. 414 cases (author's transl)]

Comparison between 157 children treated with defibrinated convalescent plasma and 257 children treated with specific immunoglobulins revealed the improved effectiveness of the latter treatment in the prevention of chickenpox. Specific Herpes Zoster-Chickenpox immunoglobulins are prepared by caprylic acid fractionation of convalescent plasma. The prevention obtained in more than 90% of cases would appear to be clinically and biologically total as shown by serological surveillance of certain children with particularly severe immune depression.

[Preventive and therapeutic effect convalescent zona and varicella sera in high risk children (659 cases)]

Study of 659 cases treated with serum from patients convalescent after herpes zoster and chickenpox over a period of two and a half years in French hospital departments, showed the obvious effectiveness of this type of therapy which seems to be better than that of zoster specific gamma globulin used by other workers since we obtained protection against chickenpox in 90 p. cent of cases, and attenuation of chickenpox in 82 p. cent. It would seem that these results could be improved by increasing the doses used.

Investigation of the recovery phenomenon in immunofluorescence after laser excitation

Laser excitation was applied in two standard immunopathological indirect immunoflorescence systems in order to investigate bleaching and recovery of fluorescence intensity upon repeated illuminations. Variation of illumination times and dark periods between these showed that the recovery phenomenon is a function of both the (time times energy) product of excitation and the length of dark intervals. The value of high energy excitation in immunofluorescence in providing insight into the mechanisms of bleaching and recovery is discussed.

Photometric evaluation of indirect immunofluorescence chessboard titrations for the characterization of FITC-labelled antibodies

The immunofluorescent staining properties of three FITC-labelled anti-human IgG rabbit globulin preparations with very similar antibody concentration (595, 570 and 565 μg/ml), but different molar fluorescein/protein ratios (4.2, 1.4 and 0.7) were compared by means of indirect immunofluorescence chessboard titrations. A selected serum from a patient with systemic lupus erythematosus containing antinuclear factors was tested on formalinized chicken red blood cells using incident light illumination. Both visual and photometric readings were taken. The characteristic pattern of chessboard titrations with a constant titre (plateau titre) over a wide range of conjugate dilutions followed by an abrupt fall (plateau end-point) was obtained and showed good correlation by both methods of evaluation. The height of the plateau titre increased with increasing fluorescein/protein ratio, but no linear relationship could be established with the three conjugates under investigation. The plateau end-point was encountered at conjugate dilutions containing similar antibody concentrations namely 9.3, 8.9 and 8.8 μg/ml. From the good correlation between photometric and visual readings it is concluded that chessboard titrations provide an objectively-acceptable method for the evaluation of fluorescent conjugates and adoption of the procedure by manufacturers of conjugates is suggested.

Microphotometry in immunofluorescence

A specially sensitive version of the Reichert microphotometer provides a means of obtaining accurate measurements of the emission of immunofluorescent microscopical preparations. The fluorescence of single particles down to 0·8 μ in diameter may be measured with all background excluded. The photometer has permitted determinations of titre of antisera, assessment of the validity of conventional visual estimation of fluorescence, and comparative studies of fluorescence intensity and fading under a variety of conditions. Preliminary studies by double immunofluorescent staining of two distinct antigenic constituents of cells which might be present either separately or together, suggest future value in investigations of cell differentiation and dedifferentiation.