Planteproduktion og fødevalg

Den overordnede baggrund for projektet var at få nogle kvantitative beskrivelser af, hvorledes man med forskellige former for ekstensiv græsmarksdrift kunne besvare eller øge artsdiversiteten på ferske enge. Samtidig ønskedes at kvantificere konsekvenserne for den landbrugsmæssige produktion på arealerne. Ferske enge varierer meget med hensyn til plantebestand, jordbundsforhold og fugtighed, og det er derfor væsentligt at kende disse faktorer, når man skal vurdere, hvilken produktion, der kan forventes på et givet engareal. Når stude og får afgræsser på halvkulturarealer er der et større udvalg af arter end der er på intensive græsmarker. Desuden er der som regel en lavere belægning, hvilket betyder at dyrene har gode muligheder for at selektere i det planteudbud, der er til rådighed. Målet med denne del af undersøgelsen var at få en beskrivelse af produktionens størrelse, foderkvalitet, artssammensætning, benyttelsens indvirkning på arterne, foderkvaliteten af enkeltarter og studenes fødevalg

Forage quality of cultivated and natural species in semi-natural grassland

The conserve or improve floristically diverse grassland areas, there is a need for some agricultural management to avois scrub vegetation. Description of the forage quality of the most common species in these swards will make it easier to make appropriate use of the forage produced. The objective was to determine forage quality by analysing for in vitro organic matter digestibility (IVOMD) and neutral detergent fibres (NDF) of individual species commonly occurring in low lying semi-natural grasslands in Denmark. Eight species of grasses, eight herb species and one species of rush were collected in June and July under grazing and cutting. However, a large variation between species was found. The IVOMD varied from 416 to 780 g kg-1 organic matter (OM) and NDF from 287 to 714 g kg-1 dry matter (DM). The herbs maintained a relatively high IVOMD in mid-summer cuts, contrary to the grasses, where a later cut resulted in a lower IVOMD. Two species often occurring in substantial amounts in such swards, Deschampsia caespitose and Juncus effuses, had low IVOMD and high NDF, and it was concluded that management strategies that reduce the occurrence of these species will increase the forage quality

Supertubes versus superconducting tubes

In this paper we show the relationship between cylindrical D2-branes and cylindrical superconducting membranes described by a generic effective action at the bosonic level. In the first case the extended objects considered, arose as blown up type IIA superstrings to D2-branes, named supertubes. In the second one, the cosmological objects arose from some sort of field theories. The Dirac-Born-Infeld action describing supertubes is shown to be equivalent to the generic effective action describing superconducting membranes via a special transformation.Comment: Version with minor text changes with respect to the already publishe

Animal production from dairy breed steers at extensively managed grasslands in riverside areas

In Denmark, some of the grassland in marginal areas are abandoned for agricultural use - grassland that it is of interest to preserve because they have a high actural or potential natural quality when managed with extensive grazing or cuttting. A comparison was carried out for three years on sward productivity and weight gain of the steers at two grazing intensities on wet semi-natural grassland. The daily weight gain of steers was on average 667 g at low and 477 g at high grazing intensity. Sward grass yield as dry matter (DM) production was on average 4.1 Mg DM ha4, with no significant difference sound between the two gazing intensities. In vitroorganic matter digestibility (IVOMD) was rexpectigely 56.4 and 53.0 at high and low grazing intensity. It is concluded that the variatin in sward productivity and sward composition between years and grazing intensities was reflected in the production of the steers

Sward structure measurements to monitor the effect of grazing in nature management situations

In Denmark private farmers under contract with the society manage many nature conservation areas on low-lying organic soil. In the contract the grazing system is poorly difined in relation to the goals and there is a lack of monitoring intruments for practical use in natural areas. Thus there is a need to define grazing system indicators, which should make it possible toevaluate effect from grazing and provide a feed-back to the goals. To describe the effect of grazing on the vegetation structure, detailed measurements of sward heights, species composition, species phenology, distance to flowering speecimens of Juncus effeusus I. or J. conglomeratus I. were carried out in paddocks grazed by 1st year steers at two different levels of plant species diversity and at two levels of grazing intensity. The aim was to identify variables able to ecpose the effect of the different treatments

Spontaneous magnetization of aluminum nanowires deposited on the NaCl(100) surface

We investigate electronic structures of Al quantum wires, both unsupported and supported on the (100) NaCl surface, using the density-functional theory. We confirm that unsupported nanowires, constrained to be linear, show magnetization when elongated beyond the equilibrium length. Allowing ions to relax, the wires deform to zig-zag structures with lower magnetization but no dimerization occurs. When an Al wire is deposited on the NaCl surface, a zig-zag geometry emerges again. The magnetization changes moderately from that for the corresponding unsupported wire. We analyse the findings using electron band structures and simple model wires.Comment: submitted to PHys. Rev.

Current-carrying cosmic string loops 3D simulation: towards a reduction of the vorton excess problem

The dynamical evolution of superconducting cosmic string loops with specific equations of state describing timelike and spacelike currents is studied numerically. This analysis extends previous work in two directions: first it shows results coming from a fully three dimensional simulation (as opposed to the two dimensional case already studied), and it now includes fermionic as well as bosonic currents. We confirm that in the case of bosonic currents, shocks are formed in the magnetic regime and kinks in the electric regime. For a loop endowed with a fermionic current with zero-mode carriers, we show that only kinks form along the string worldsheet, therefore making these loops slightly more stable against charge carrier radiation, the likely outcome of either shocks or kinks. All these combined effects tend to reduce the number density of stable loops and contribute to ease the vorton excess problem. As a bonus, these effects also may provide new ways of producing high energy cosmic rays.Comment: 11 pages, RevTeX 4 format, 8 figures, submitted to PR

Treatment planning for patients with low rectal cancer in a multicenter prospective organ preservation study

Background Non-surgical management of rectal cancer relies on (chemo)radiotherapy as the definitive treatment modality. This study reports and evaluates the clinical high dose radiotherapy treatment plans delivered to patients with low resectable rectal cancer in a Danish multicenter trial. Methods The Danish prospective multicenter phase II Watchful Waiting 2 trial (NCT02438839) investigated definitive chemoradiation for non-surgical management of low rectal cancer. Three Danish centers participated in the trial and committed to protocol-specified treatment planning and delivery requirements. The protocol specified a dose of 50.4 Gy in 28 fractions to the elective volume (CTV-/PTV-E) and a concomitant boost of 62 Gy in 28 fractions to the primary target volume (CTV-/PTV-T). Results The trial included 108 patients, of which 106 treatment plans were available for retrospective analysis. Dose coverage planning goals for the main target structures were fulfilled for 94% of the treatment plans. However, large intercenter differences in doses to organs-at-risk (OARs) were seen, especially for the intestines. Five patients had a V60Gy>10 cm3 for the intestines and two patients for the bladder. Conclusion Prescribed planning goals for target coverage were fulfilled for 94% of the treatment plans, however analysis of OAR doses and volumes indicated intercenter variations. Dose escalation to 62 Gy (as a concomitant boost to the primary tumor) introduced no substantial high dose volumes (>60 Gy) to the bladder and intestines. The treatment planning goals may be used for future prospective evaluation of highdose radiotherapy for organ preservation for low rectal cancer

UHECR as Decay Products of Heavy Relics? The Lifetime Problem

The essential features underlying the top-down scenarii for UHECR are discussed, namely, the stability (or lifetime) imposed to the heavy objects (particles) whatever they be: topological and non-topological solitons, X-particles, cosmic defects, microscopic black-holes, fundamental strings. We provide an unified formula for the quantum decay rate of all these objects as well as the particle decays in the standard model. The key point in the top-down scenarii is the necessity to adjust the lifetime of the heavy object to the age of the universe. This ad-hoc requirement needs a very high dimensional operator to govern its decay and/or an extremely small coupling constant. The natural lifetimes of such heavy objects are, however, microscopic times associated to the GUT energy scale (sim 10^{-28} sec. or shorter). It is at this energy scale (by the end of inflation) where they could have been abundantly formed in the early universe and it seems natural that they decayed shortly after being formed.Comment: 11 pages, LaTex, no figures, updated versio