Ognina - a puzzling prehistoric site in Sicily

In 1965, Prof. Bernabo Brea of Syracuse excavated a site on the small island of Ognina, off the east coast of Sicily 12 km south of Syracuse. He found two levels of prehistoric occupation, a lower one of the Early Neolithic Stentinello Culture, and an upper one dating to the Early Bronze Age. At these periods, however, it may not have been an island but rather a small promontory beside a sheltered inlet, making an ideal small port. The Bronze Age material contained none of the Castelluccio Culture, widespread in South-east Sicily at the time, but pottery which Brea recognised as being closely similar to some which John Evans had found in Tarxien Cemetery contexts in Malta. He therefore suggested that the site had been refounded at this period, after standing empty since the Early Neolithic, by emigrants from Malta, who had probably established it as a trading post for their commercial interchanges with the Sicilians. This was adopted as the orthodox view by Italian prehistorians down to the present day. However, some uneasiness was felt among those studying Maltese prehistory, on the grounds that there was very little evidence for a sea-faring tradition in that early period, and though there were undoubtedly some raw materials imported into the islands, this was on a comparatively small scalepeer-reviewe

Non-inversion tillage in organic arable cropping

The opportunities for using an non-inversion tillage (NI) approach in organic systems has not been well investigated by research and what research has been done has not perhaps been sufficiently long-term. The benefits of the system in terms of the economics of establishment and the improvement in soil quality make the system attractive, but it is a system that will take some time to get established and is one that will require the farmer to “hold his nerve” as grass weed, perennial weed burdens and slug predation may increase in the early years of implementation. In conventional systems and the POB work yields have reported to drop when implementing an NI system. This is before some of the benefits of a better quality soil are seen, but in the work done by Dr Michael Brandt in an organic system no yield drop was experienced. This was also the case for Danish work done by Per Schonning. Phosphate (P) and Nitrate (N) losses can be reduced as soil structure improves and becomes more stable. Better water ingress into the soil will reduce run-off and sediment and P loss and better water retention in the soil structure will reduce leaching potential. This is perhaps particularly the case at the time that the ley phase of a rotation is broken when greatest risks of N leaching occurs particularly if this coincides with significant rainfall

Xewkija and elsewhere : new thoughts on old sites

In this article the author speculates and discusses possible new interpretations of lost megalithic sites throughout Malta and Gozo. His interpretations are based both on the old excavation notes by former archaeologists and new knowledge about the prehistory of Malta.peer-reviewe

Getaway Special competition: Overview

Recommendations submitted for experiments to be conducted onboard the space shuttle are presented. Short biographies of the finalists in the Get Away Special (GAS) competition were included

Market Review of the Welsh Organic Arable Sector, 2007

The supply situation for Welsh organic arable production Organic production in Wales has been developing steadily in the last five years, with particular emphasis on organic cattle and sheep production. This was despite over-supply conditions in some sectors, notably dairy, following the very rapid growth in 1999/2000. The area of organic arable production has tracked this increase albeit at a lower level. It is also a more complex situation than might be thought because of the different ways in which a cereal crop or mixture might be harvested. This sector is one of the least surveyed in the UK with the exception of the annual Scottish Organic Market Link Producer Survey carried out by SAC with SEERAD funding. Between the end of 2002 and end of 2005, the number of holdings increased by 12% to 688, and the certified land area increased by 29% to 71 thousand hectares, of which more than 90% is grassland. Growth in Wales has exceeded other parts of the UK, reaching 5% of agricultural land by end 2005. More rapid growth is projected for 2006 and possibly 2007. The arable area reported to Defra shows an increase over the period 2003 to 2005 (reported as end of January 2004 to end of January 2006) from 1958 ha to 2358 ha. This represents a 20% increase over the period at a time when organic grassland of all types increased by 34%. The UK position for the supply and demand of organic cereals is giving considerable cause for concern at the present particularly in the area of organic livestock feed. This has been brought about by marked increases in organic milk, pork, egg and poultry sales along with continuing expansion of the red meat sectors. This has led to a considerable imbalance that is likely to get worse over the coming years, something that will be amplified by changes in the standards with respect to non organic feed allowances. It is estimated that the UK is around 60% self sufficient in home produced feed grain – the shortfall is made up of imports from around the world and a number of factors are threatening the security of supply from many of the exporting countries. The calculations involved are subject to a number of crude assumptions and there is universal agreement that there is an urgent need for information and regularly updated statistics. Actual output of Welsh arable producers is extremely difficult to quantify precisely because it is not monitored with the regularity and at the level of detail of other sectors. Two sets of figures are available but they are difficult to compare because one relates to areas planted while the other is concerned with outputs. A producer survey was undertaken using a detailed telephone questionnaire. This was not a simple exercise as it proved difficult to obtain information from certification bodies. This meant that it was difficult to identify advance those producers that were growing arable crops. 209 producers out of a total of 502 livestock producers were contacted, responses received from 102 (a response rate of just under 50%) and 40 of these were arable producers. This cohort represented 913 ha of arable production or 29.5% of the total organic arable area in Wales. 39% of the arable crops grown by respondents were planted as mixtures (usually a cereal/protein mix), a notable difference from earlier surveys. Of the pure stands wheat comprised the largest area followed by barley, oats, triticale and beans in descending order. 50% of the crops surveyed were harvested as whole crop and 47% as grain with a total yield of 1,458 tonnes. In the year under survey the highest proportion of a single crop harvested as whole crop was wheat while oats constituted the largest harvested grain crop, results that were somewhat at odds with other work but are almost certainly a result of what was a hot, dry season with low silage yields. Only 455t of grain was actually marketed with barley accounting for the highest proportion and wheat the lowest. Yields as reported by the farmers contacted tended to be on the low side with respect to standard figures in the Organic Farm Management Handbook although oats were slightly better. Triticale was particularly poor at around 50% of standard yields. The same cohort of respondents reported reduced areas for the 2007 season, an overall reduction of 21% on 2006 figures, and an anticipated reduction in grain to be marketed (16%). Producers reported that poor producer prices are a disincentive to growing grain for the market, a somewhat surprising conclusion given the recent strong movements in organic cereal prices. Transport costs are a significant factor as the crop has to be moved out of Wales to grain merchants and/or feed mills. Extrapolation of the above figures is recognised as a risky and imperfect process but it does raise a number of questions of concern not least the existence of a decline when overall conversion and livestock numbers are increasing This was followed by a trade survey that contacted both the grain trade and compound feed producers. The responses were not all encompassing but covered 75% of the active traders in numerical terms. The responses indicated that very small quantities of grain are supplied into Wales for processing – most grain traded moved to other producers within Wales. The vast majority of feed is imported in the form of compound feed and on the basis of the responses received totalled some 13,600 tonnes for the 2006 season. Allowing for non responses it is estimated that the actual figure was around 16,000 tonnes – 11,000 t for ruminants and 5,000 t as poultry rations. Feed compounders are working on the basis of demand increasing by around 20% year on year, partly as a result of changes to the standards. It is estimated that the demand for poultry feed will increase to 9,000 t in 2009 while ruminant feed is predicted to increase to 19,000 t in 2009, a total of 28,000t. It is suggested that the cereal and protein crop requirements will be in the order of 50% of the total i.e. 14,000 t each. There is a very low level of protein production in Wales and this demand will almost certainly be fulfilled through the use of imported sources of soya. A SWOT analysis was undertaken that concluded that there are more weaknesses than strengths but that there are a number of opportunities for increases arable production not least the strengthening of prices across the board. The area of most concern and seen as a serious threat is the reported 21% decrease in plantings for the current season. Recommendations Despite the generally positive outlook from a demand perspective, there is a need to address some of the factors that might discourage producers from converting, including disruption to the Organic Farming Scheme, price levels that do not always reflect the costs of production, access to markets and a distinct lack of support for the sector. To address this, there is a need for: • better statistical data on current and future production levels and market shares and a wider appreciation of the need for improved levels of self sufficiency; • greater publicity should be given to events and trends in the wider organic cereal market to ensure that Welsh organic livestock producers have all the facts when planning for the future; • a series of events, articles and other media coverage and special attention should be given to these issues in the Organic Market Wales e-bulletin; • enhanced payments through the OFS through a mechanism that replaces the previous AAPS rate; • the new Farming Connect service to focus on the potential for home grown feed when working with organic livestock producers; • an increasing focus on education in order to signpost opportunities for young people; • an evaluation of the potential for the establishment of an organic feed compounding operation in Wales – this could reduce costs and also provide market opportunities for arable producers; • improved production systems, supported by effective research and development and knowledge transfer; • parallel improvements in variety and mixture choices – this may involve new introductions, a re-evaluation of varieties deemed to have been out-classed and the development of landraces; • a clear identification of suitable areas for organic arable production along with guidance on what crops to grow in the particular soil types and prevailing climate • improved integration of effort between organic sector businesses and the agencies that support the development of the Welsh horticultural and organic sectors; • improved linkages with the dairy, arable and red meat sectors to benefit from complementarity relationships between the sectors at production, market development and promotional levels

Evolution of Broad-line Emission from Active Galactic Nuclei

Apart from viewing-dependent obscuration, intrinsic broad-line emission from active galactic nuclei (AGNs) follows an evolutionary sequence: Type $1 \to 1.2/1.5 \to 1.8/1.9 \to 2$ as the accretion rate onto the central black hole is decreasing. This spectral evolution is controlled, at least in part, by the parameter $L_{\rm bol}/M^{2/3}$, where $L_{\rm bol}$ is the AGN bolometric luminosity and $M$ is the black hole mass. Both this dependence and the double-peaked profiles that emerge along the sequence arise naturally in the disk-wind scenario for the AGN broad-line region.Comment: MNRAS, to be publishe

A CANDELS WFC3 Grism Study of Emission-Line Galaxies at z ~ 2: A Mix of Nuclear Activity and Low-Metallicity Star Formation

We present Hubble Space Telescope Wide Field Camera 3 (WFC3) slitless grism spectroscopy of 28 emission-line galaxies at z ~ 2, in the GOODS-S region of the Cosmic Assembly Near-infrared Deep Extragalactic Legacy Survey. The high sensitivity of these grism observations, with >1σ detections of emission lines to f > 2.5 × 10^(–18) erg s^(–1) cm^(–2), means that the galaxies in the sample are typically ~7 times less massive (median M_* = 10^(9.5) M_☉) than previously studied z ~ 2 emission-line galaxies. Despite their lower mass, the galaxies have [O III]/Hβ ratios which are very similar to previously studied z ~ 2 galaxies and much higher than the typical emission-line ratios of local galaxies. The WFC3 grism allows for unique studies of spatial gradients in emission lines, and we stack the two-dimensional spectra of the galaxies for this purpose. In the stacked data the [O III] emission line is more spatially concentrated than the Hβ emission line with 98.1% confidence. We additionally stack the X-ray data (all sources are individually undetected), and find that the average L_([O III])/L_(0.5-10keV) ratio is intermediate between typical z ~ 0 obscured active galaxies and star-forming galaxies. Together the compactness of the stacked [O III] spatial profile and the stacked X-ray data suggest that at least some of these low-mass, low-metallicity galaxies harbor weak active galactic nuclei