Influence of Grassland Management and Grazing by Different Farm Animals on Animal Performance and Flora Alterations

The objectives of this study were to test the possibilities of using different farm animals for landscape care on extensive pasture, taking into account their particular performance, and to analyse alterations of the flora in consequence of grazing by different animals and various pasture management. Salers had the highest (836g/d) and Galloways (584g/d) the lowest live weight gain as compared with the other breeds (771g/d). Lambs had higher live weight when grazing together with cattle and horses (mixed grazing) than under one species grazing. The number of legume increased and that of grass decreased. Following 3 years the grazing animals effected an increase of plant numbers in order of: Horses 86%, Cattle 15%, Mixed grazing 14% and sheep no effect. The most success of increasing plant numbers was registered when combined grazing and mowing of pasture was used

Long Term Observation of the Grassland Vegetation Used Intensively or Extensively and Ecologically

The aim of the present paper was to study alterations of the grassland flora from 55 plots following a more extensive management under long term observation within 6 years. Extensification of grassland use leads to an increase of the numbers of plant species by 32%, “Red-list-species” included. The moisture number of the soils slightly increased and the reaction and nitrogen numbers decreased. Results are presented for different vegetation units

Versatile compact atomic source for high resolution dual atom interferometry

We present a compact $^{87}$Rb atomic source for high precision dual atom interferometers. The source is based on a double-stage magneto-optical trap (MOT) design, consisting of a 2-dimensional (2D)-MOT for efficient loading of a 3D-MOT. The accumulated atoms are precisely launched in a horizontal moving molasses. Our setup generates a high atomic flux ($>10^{10}$ atoms/s) with precise and flexibly tunable atomic trajectories as required for high resolution Sagnac atom interferometry. We characterize the performance of the source with respect to the relevant parameters of the launched atoms, i.e. temperature, absolute velocity and pointing, by utilizing time-of-flight techniques and velocity selective Raman transitions.Comment: uses revtex4, 9 pages, 12 figures, submitted to Phys. Rev.

Interspecific trait variability and local soil conditions modulate grassland model community responses to climate

Medium‐to‐high elevation grasslands provide critical services in agriculture and ecosystem stabilization, through high biodiversity and providing food for wildlife. However, these ecosystems face elevated risks of disruption due to predicted soil and climate changes. Separating the effects of soil and climate, however, is difficult in situ, with previous experiments focusing largely on monocultures instead of natural grassland communities. We experimentally exposed model grassland communities, comprised of three species grown on either local or reference soil, to varied climatic environments along an elevational gradient in the European Alps, measuring the effects on species and community traits. Although species‐specific biomass varied across soil and climate, species' proportional contributions to community‐level biomass production remained consistent. Where species experienced low survivorship, species‐level biomass production was maintained through increased productivity of surviving individuals; however, maximum species‐level biomass was obtained under high survivorship. Species responded directionally to climatic variation, spatially separating differentially by plant traits (including height, reproduction, biomass, survival, leaf dry weight, and leaf area) consistently across all climates. Local soil variation drove stochastic trait responses across all species, with high levels of interactions occurring between site and species. This soil variability obscured climate‐driven responses: we recorded no directional trait responses for soil‐corrected traits like observed for climate‐corrected traits. Our species‐based approach contributes to our understanding of grassland community stabilization and suggests that these communities show some stability under climatic variation

Gauss sum factorization with cold atoms

We report the first implementation of a Gauss sum factorization algorithm by an internal state Ramsey interferometer using cold atoms. A sequence of appropriately designed light pulses interacts with an ensemble of cold rubidium atoms. The final population in the involved atomic levels determines a Gauss sum. With this technique we factor the number N=263193.Comment: 4 pages, 5 figure

Leukoencephalopathy upon disruption of the chloride channel ClC-2

ClC-2 is a broadly expressed plasma membrane chloride channel that is modulated by voltage, cell swelling, and pH. A human mutation leading to a heterozygous loss of ClC-2 has previously been reported to be associated with epilepsy, whereas the disruption of Clcn2 in mice led to testicular and retinal degeneration. We now show that the white matter of the brain and spinal cord of ClC-2 knock-out mice developed widespread vacuolation that progressed with age. Fluid-filled spaces appeared between myelin sheaths of the central but not the peripheral nervous system. Neuronal morphology, in contrast, seemed normal. Except for the previously reported blindness, neurological deficits were mild and included a decreased conduction velocity in neurons of the central auditory pathway. The heterozygous loss of ClC-2 had no detectable functional or morphological consequences. Neither heterozygous nor homozygous ClC-2 knock-out mice had lowered seizure thresholds. Sequencing of a large collection of human DNA and electrophysiological analysis showed that several ClC-2 sequence abnormalities previously found in patients with epilepsy most likely represent innocuous polymorphisms

Worldwide evidence of a unimodal relationship between productivity and plant species richness

The search for predictions of species diversity across environmental gradients has challenged ecologists for decades. The humped-back model (HBM) suggests that plant diversity peaks at intermediate productivity; at low productivity few species can tolerate the environmental stresses, and at high productivity a few highly competitive species dominate. Over time the HBM has become increasingly controversial, and recent studies claim to have refuted it. Here, by using data from coordinated surveys conducted throughout grasslands worldwide and comprising a wide range of site productivities, we provide evidence in support of the HBM pattern at both global and regional extents. The relationships described here provide a foundation for further research into the local, landscape, and historical factors that maintain biodiversity

Numerical investigation of the particle skeleton of widely graded soils prone to suffusion

The soil structure affects directly the capability of distributing and transmitting forces between its particles. Thus, the particle arrangement dictates the performance of soil under hydraulic and dynamic loads. This paper describes an analysis method in which the skeletal force chains of the particle assembly (packing) can be identified based on Discrete-Element-Method (DEM) modelling. For the simulations the software LIGGGHTS is used. A widely graded particle size distribution (PSD) is investigated to find correlations between PSD and the micromechanical properties of the particle assemblies. These PSD is based on common internal stability criteria prone to suffusion. The different roles of fractions of the PSD in packings and the force chains under specified load are analysed. Therefor a packing is generated with the Modified-Force-Biased-Algorithm (MFBA). A method based on the bimodality of widely graded PSDs is proposed to differentiate the soil skeleton and the fill of packings of such a PSD. Particle contact number and contact forces are evaluated to identify the amount of loose particles, which are potentially mobile particles. The influence of the packing homogeneity on its skeleton is also addressed. The described method provides a better understanding of the soil structure as well as of internally stability of widely graded soil

Experimental identification of the dominant fabric in widely graded soils

To estimate the vulnerability of widely graded soils to internal erosion, the soil structure has to be analysed. Based on the theory of the bimodal fabric, each particle size distribution (PSD) has a unique diameter that divides the PSD into particles of the soil skeleton and finer mobile particles. The particle diameter, which divides the PSD into these two fractions, is defined as the separation point (dT) and part of the soil skeleton. In this study the Sequential Fill Test (SFT) is used to identify the mobility of particle fractions and the soil matrix. This study is an extension of a series of descriptions of this particular test method. The paper is focused on a widely graded PSD, which is prone to internal erosion. This study demonstrates the change of the soil matrix by variation of the amount of the fine particles. The soil matrix of the investigated PSD does not change until the pore volume is completely filled with mobile particles. If the mobile particles filled completely the pore volume of the coarse soil skeleton, they become also part of the soil skeleton. This matrix is called dual matrix. With further increase of the amount of fine particles, the coarse skeleton is replaced by a new skeleton, where all particles belong to the soil skeleton. For the assessment of a selected PSD, which is prone to internal erosion, it is important to identify the amount of fine fractions, which can stabilize an internally instable dominant fine matrix (i.e. building a dual matrix)