A broiler chicken produces an average 115g excrements a day; this amounts to 2 million tons a year in Germany alone. In terms of plant nutrients this is equivalent to 33 million kg nitrogen (N) and 7 million kg phosphorus (P). The environmetal effects of these nutrients and their interaction with different production systems has been investigated by scientists of the Institute of Plant Nutrition and Soil Science of the Federal Agricultural Research Centre (FAL) in Braunschweig, Germany.
Intensive indoor broiler production
Photograph: Martina Wolf-Reuter
Organic free range broiler production wth mobile housing
Photograph: Martina Wolf-Reuter
A nationwide study compared intensive indoor, free range and organic broiler production systems. In the intensive indoor system with 22-24 animals per square metre, i.e. altogether 20,000-40,000 animals in one building (picture 1), the birds achieve their final weight of 1.8 kg after roughly 6 weeks and during that time they have produced "only" about 5 kg excrements per broiler. However these accumulated high amounts of excrements cannot be disposed of easily and only by following the approved codes of "good agrcultural practice", which states the amount per acre according to be applied according to the approved N and P needs of plants.
The free range chicken, shares a square meter with 13 others, in flocks of about 6,000-15,000 birds and an average stocking rate of about 1 m2 per bird in the free range. This makes their life not only more varied but also a bit longer. In spite of the same final fattening weight of 1.8 kg, their life is extended by two weeks, which therefore leaves more droppings. An additional problem: During the study the birds mostly stayed near their building, so hardly more than 30 % of the actual exercise area was used with the consequence, that it received a far higher enrichment with N and P, to the extent that it was a potential pollution risk to the ground- and surface waters.
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Controlling electronic current is essential to modern electronics, as data and signals are transferred by streams of electrons which are controlled at high speed. Demands on transmission speeds are also increasing as technology develops. Scientists from the Chair of Laser Physics and the Chair of Applied Physics at Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU) have succeeded in switching on a current with a desired direction in graphene using a single laser pulse within a femtosecond ¬¬ – a femtosecond corresponds to the millionth part of a billionth of a second. This is more than a thousand times faster compared to the most efficient transistors today.
Graphene is up to the job
At the productronica trade fair in Munich this November, the Fraunhofer Institute for Laser Technology ILT will be presenting Laser-Based Tape-Automated Bonding, LaserTAB for short. The experts from Aachen will be demonstrating how new battery cells and power electronics can be micro-welded more efficiently and precisely than ever before thanks to new optics and robot support.
Fraunhofer ILT from Aachen relies on a clever combination of robotics and a laser scanner with new optics as well as process monitoring, which it has developed...
Plants and algae use the enzyme Rubisco to fix carbon dioxide, removing it from the atmosphere and converting it into biomass. Algae have figured out a way to increase the efficiency of carbon fixation. They gather most of their Rubisco into a ball-shaped microcompartment called the pyrenoid, which they flood with a high local concentration of carbon dioxide. A team of scientists at Princeton University, the Carnegie Institution for Science, Stanford University and the Max Plank Institute of Biochemistry have unravelled the mysteries of how the pyrenoid is assembled. These insights can help to engineer crops that remove more carbon dioxide from the atmosphere while producing more food.
A warming planet
Our brains house extremely complex neuronal circuits, whose detailed structures are still largely unknown. This is especially true for the so-called cerebral cortex of mammals, where among other things vision, thoughts or spatial orientation are being computed. Here the rules by which nerve cells are connected to each other are only partly understood. A team of scientists around Moritz Helmstaedter at the Frankfiurt Max Planck Institute for Brain Research and Helene Schmidt (Humboldt University in Berlin) have now discovered a surprisingly precise nerve cell connectivity pattern in the part of the cerebral cortex that is responsible for orienting the individual animal or human in space.
The researchers report online in Nature (Schmidt et al., 2017. Axonal synapse sorting in medial entorhinal cortex, DOI: 10.1038/nature24005) that synapses in...
Whispering gallery mode (WGM) resonators are used to make tiny micro-lasers, sensors, switches, routers and other devices. These tiny structures rely on a...
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