N, P and K budgets for crop rotations on nine organic farms in the UK

On organic farms, where the importation of materials to build/maintain soil fertility is restricted, it is important that a balance between inputs and outputs of nutrients is achieved to ensure both short-term productivity and long-term sustainability. This paper considers different approaches to nutrient budgeting on organic farms and evaluates the sources of bias in the measurements and/or estimates of the nutrient inputs and outputs. The paper collates 88 nutrient budgets compiled at the farm scale in 9 temperate countries. All the nitrogen (N) budgets showed an N surplus (average 83.2 kg N ha-1 year-1). The efficiency of N use, defined as outputs/inputs, was highest (0.9) and lowest (0.2) in arable and beef systems respectively. The phosphorus (P) and potassium (K) budgets showed both surpluses and deficits (average 3.6 kg P ha-1 year-1, 14.2 kg K ha-1 year-1) with horticultural systems showing large surpluses resulting from purchased manure. The estimation of N fixation and quantities of nutrients in purchased manures may introduce significant errors in nutrient budgets. Overall, the data illustrate the diversity of management systems in place on organic farms, and suggest that used together with soil analysis, nutrient budgets are a useful tool for improving the long-term sustainability of organic systems

Comparison of Goal Achievement When Transitioning from In-Person Therapy to Teletherapy in the Westchester County Early Intervention Program Due to the COVID-19 Pandemic

The sudden transition to virtual therapeutic services during the COVID-19 pandemic provided a unique opportunity to explore telehealth as a platform for delivering early intervention (EI) services. Through retrospective chart review of 93 children, we collected the following data: demographics, diagnosed conditions, therapy type, service format, and provider-reported participant goal achievement (1=no progress, 2=little progress, 3=moderate progress, 4=great deal of progress, 5=outcome achieved) over a six-month period before and after transitioning to telehealth. Pre- and post-transition progress scores were compared using the Wilcoxon signed-rank test. Results demonstrated maintained progress among children who transitioned from in-person to virtual services for similar therapy types. Children receiving speech therapy in-person and virtually demonstrated increased achievement (3.00 vs 3.33; p=0.032). Participants receiving a particular therapy post-transition but not in-person attained similar achievement as those who received the same therapy only in-person. Our research suggests that teletherapy may be a viable option for delivering EI services. &nbsp

Planet Packing Revisited

Ross Eckler discusses a problem in his article Planet Packing in the May 2001 Word Ways: given a list of words, such as the names of the planets, how efficiently can they be packed into a single string of characters so that each word on the list can be read off left to right (but not necessarily contiguously)? He hypothesizes there is no guarantee that any algorithm will end up with a minimum string. Since the design and analysis of algorithms has been my area of research for some 25 years, this caught my attention. Informally, an algorithm is a terminating procedure that could be coded as a computer program. (However, the procedure in the Planet Packing article does not contain enough tie-breaking rules to qualify as an algorithm)

Elm Farm Organic Research Centre Bulletin 83 April 2006

Regular bulleting with technical updates from Organic Advisory Service Issue contains: Testing for Tolerance - a pragmatic view GM Debate Vaccination nation - to jab or not to jab Future shape of OCIS Evolutionary wheat makes the grade? NIAB tracks health of organic cereal seed Stopping erosion of soil quality - the organic way Care needed to halt butterfly collapse Aspects of poultry behaviour: How free range is free range? On choosing an organic wheat A local education challenge New Wakelyns Science Building Organic vegetable market growt

Diversifikationsstrategien für das Management der Kraut-und Knollenfäule der Kartoffel

Fazit: Die bisherigen Ergebnisse deuten auf eine extreme Sortenabhängigkeit in den epidemiologischen Effekten von Diversifikationsstrategien hin. Außerdem spielt die Variabilität des Befallsdruckes selbst innerhalb eines Feldes eine kritische Rolle. Für die Auswertung von Daten muß deshalb die räumliche Verteilung des Befalles viel stärker mit entsprechenden statistischen Modellen in Betracht gezogen werden. Die Ergebnisse aus den Streifenexperimenten sind analog den Ergebnissen aus den Sortenmischungen und deuten darauf hin, daß Kartoffeln extrem empfindlich auf Konkurrenz sowohl verschiedener Sorten als auch Arten reagieren. Um Diversifikationsstrategien sinnvoll einsetzen zu können, sollten als erstes die Reaktionen von Sorten auf andere Sorten und Arten quantifiziert werden, um geeignete Sorten zu identifizieren. Es könnte auch ein Zuchtziel für die ökologische Landwirtschaft werden, die Konkurrenzfähigkeit mehr in den Vordergrund zu stellen. Dies wäre auch in Bezug auf Unkrautunterdrückung unter Umständen von Interesse. Um ein Streifenexperiment sinnvoll auszuwerten, muß der Ertrag und Befall der Außen- und Innenreihen von Parzellen getrennt erfaßt werden. Für die Beurteilung des Gesamtergebnisses kann dann nicht einfach auf Hektarerträge hochgerechnet werden sondern es muß das Gesamtsystem in Betracht gezogen werden. Insgesamt können Diversifikationsstrategien den Krankheitsdruck reduzieren. Dies belegen auch Beobachtungen aus China, wo der Streifenanbau von Kartoffeln und Mais zu bis zu 40% Reduktion im Befall mit P. infestans und damit zu einer Reduktion im Fungizideinsatz geführt hat (Z. Youyong, 2002, pers. Mitteilung)

Limiter lock systems at TEXTOR: flexible tools for plasma-wall investigation

Limiter lock systems on the top and the bottom of the TEXTOR vessel are essential elements for experimental investigations of plasma-wall interaction in a tokamak. The lock systems are designed as user facilities that allow the insertion of wall elements (limiter) and tools for diagnostic (electrical probes, gas injection) without breaking the TEXTOR vacuum. The specially designed holder on top of the central carrier and a powerful vacuum pump system permit the exchange of components within similar to1 h. Up to ten electrical signals, four thermocouples, and a gas supply can be connected at the holder interface. Between discharges, the inserted component can be positioned radially and turned with respect to the toroidal magnetic field. Additionally, the central carrier is electrically isolated to apply bias voltages and currents up to 1 kV and 1 kA, respectively.An important feature of the lock system is the good access for optical spectroscopic observation of the inserted components in the vicinity of the edge plasma. The whole spectrum from ultraviolet to infrared is covered by spectrometers and filters combined with cameras. Toroidally and poloidally resolved measurements are obtained front the view on top of the probes while the tangential poloidal view delivers radially and toroidally resolved information.A programmable logic controller (Simatic S5) that is operated inside the TEXTOR bunker and from remote locations outside the concrete wall drives all possible features of the lock system

Beryllium migration in JET ITER-like wall plasmas

JET is used as a test bed for ITER, to investigate beryllium migration which connects the lifetime of first-wall components under erosion with tokamak safety, in relation to long-term fuel retention. The (i) limiter and the (ii) divertor configurations have been studied in JET-ILW (JET with a Be first wall and W divertor), and compared with those for the former JET-C (JET with carbon-based plasma-facing components (PFCs)). (i) For the limiter configuration, the Be gross erosion at the contact point was determined in situ by spectroscopy as between 4% (E-in = 35 eV) and more than 100%, caused by Be self-sputtering (E-in = 200 eV). Chemically assisted physical sputtering via BeD release has been identified to contribute to the effective Be sputtering yield, i.e. at E-in = 75 eV, erosion was enhanced by about 1/3 with respect to the bare physical sputtering case. An effective gross yield of 10% is on average representative for limiter plasma conditions, whereas a factor of 2 difference between the gross erosion and net erosion, determined by post-mortem analysis, was found. The primary impurity source in the limiter configuration in JET-ILW is only 25% higher (in weight) than that for the JET-C case. The main fraction of eroded Be stays within the main chamber. (ii) For the divertor configuration, neutral Be and BeD from physically and chemically assisted physical sputtering by charge exchange neutrals and residual ion flux at the recessed wall enter the plasma, ionize and are transported by scrape-off layer flows towards the inner divertor where significant net deposition takes place. The amount of Be eroded at the first wall (21 g) and the Be amount deposited in the inner divertor (28 g) are in fair agreement, though the balancing is as yet incomplete due to the limited analysis of PFCs. The primary impurity source in the JET-ILW is a factor of 5.3 less in comparison with that for JET-C, resulting in lower divertor material deposition, by more than one order of magnitude. Within the divertor, Be performs far fewer re-erosion and transport steps than C due to an energetic threshold for Be sputtering, and inhibits as a result of this the transport to the divertor floor and the pump duct entrance. The target plates in the JET-ILW inner divertor represent at the strike line a permanent net erosion zone, in contrast to the net deposition zone in JET-C with thick carbon deposits on the CFC (carbon-fibre composite) plates. The Be migration identified is consistent with the observed low long-term fuel retention and dust production with the JET-ILW.EURATOM 63305

Group theoretical approach to quantum fields in de Sitter space I. The principal series

Using unitary irreducible representations of the de Sitter group, we construct the Fock space of a massive free scalar field. In this approach, the vacuum is the unique dS invariant state. The quantum field is a posteriori defined by an operator subject to covariant transformations under the dS isometry group. This insures that it obeys canonical commutation relations, up to an overall factor which should not vanish as it fixes the value of hbar. However, contrary to what is obtained for the Poincare group, the covariance condition leaves an arbitrariness in the definition of the field. This arbitrariness allows to recover the amplitudes governing spontaneous pair creation processes, as well as the class of alpha vacua obtained in the usual field theoretical approach. The two approaches can be formally related by introducing a squeezing operator which acts on the state in the field theoretical description and on the operator in the present treatment. The choice of the different dS invariant schemes (different alpha vacua) is here posed in very simple terms: it is related to a first order differential equation which is singular on the horizon and whose general solution is therefore characterized by the amplitude on either side of the horizon. Our algebraic approach offers a new method to define quantum field theory on some deformations of dS space.Comment: 35 pages, 2 figures ; Corrected typo, Changed referenc