Farmington Meteorite: A fragment of an Apollo asteriod?

We have attempted to reconstruct the orbit of the Farmington L5 chondrite which fell in Kansas in 1890. Because its radiation age is uniquely short (25 000 years), its orbit should still closely resemble that of its parent body. A search of 280 contemporary newspapers and other sources turned up more than 60 useable eyewitness reports from 32 localities, which led to the following estimate of the apparent radiant: height 60°, azimuth 20°, with an uncertainty of about 10°. Orbital elements were determined for this radiant for four plausible preatmospheric velocities: 13, 16, 19, and 22 km/sec. The results show quite definitely that Farmington had a small orbit of low inclination: semimajor axis 1–1.9 AU, perihelion ? 0.4 AU, aphelion ? 3.0 AU, inclination ? 16°. Because of the short radiation age, the parent body of Farmington must already have been in an Earth-crossing orbit when the meteorite was ejected from it by an impact. Of the 11 known Earth-crossing asteroids with encounter velocities below 22 km/sec, 1862 Apollo, Hermes, and 1865 Cerberus are passable matches, while 1620 Geographos and 1685 Toro are more marginal possibilities. Apparently Earth-crossing asteroids are the immediate parent bodies of at least some meteorites. Their ultimate source must be the ultimate source of most stony meteorites.     

Studying the influence of turbulent mixing on thermonuclear burning regimes during X-ray bursts of neutron stars using the <Emphasis Type="Italic">K</Emphasis><Subscript><Emphasis Type="Italic">ε</Emphasis></Subscript> model

We study the influence of turbulent mixing on the development of thermonuclear flashes in the surface layers of neutron stars. A simple K _ε model that includes various physical processes is used to describe the turbulent processes. In contrast to the widespread mixing-length theory, the K _ε model does not require using additional dimensional parameters, traces the development of turbulence in dynamics, describes the various turbulence development scenarios (gravitational and shear instabilities, convection, semiconvection, etc.) in a unified way, and can be used in multidimensional numerical simulations. Empirical constants of the model are chosen on the basis of experimental data and direct numerical simulations of typical processes. We have used the Era and Tigr-3T software packages to numerically simulate thermonuclear flashes in the accretion-renewable atmospheres of neutron stars. Turbulence is shown to accelerate significantly the transport of released energy to the stellar surface. Mixing equalizes the concentrations of matter components throughout the burning layer and increases the amount of matter involved in the thermonuclear burning during a flash.     

Spatiotemporal variability of drought on a short–medium time scale in the Calabria Region (Southern Italy)

The study analyses spatial and temporal patterns of drought in an area with a wide range of precipitation characteristics (the Calabria region in southern Italy) during the period 1921?C2007. The short-time (2, 3 and 6?months) Standardised Precipitation Index (SPI) was estimated to analyse drought especially from the agricultural point of view. Principal component analysis (PCA) was applied to the SPI to assess the spatial variability of drought. During the period of observation, moderate to severe drought occurred at a frequency of almost 13?% in wet seasons (autumn and winter). Almost half of the region was affected by drought in the years 1981?C1990 when the area experienced its most severe drought. Although the spatial patterns of drought estimated by PCA were logical and consistent with precipitation distribution, very complex patterns were observed for all the time scales looked at. The high fragmentation of the maps obtained makes them of limited value, and caution is recommended in classifying the region into homogeneous areas.     

An overview of Calanus helgolandicus ecology in European waters

We review current knowledge and understanding of the biology and ecology of the calanoid copepod Calanus helgolandicus in European waters, as well as provide a collaborative synthesis of data from 18 laboratories and 26 sampling stations in areas distributed from the northern North Sea to the Aegean and Levantine Seas. This network of zooplankton time-series stations has enabled us to collect and synthesise seasonal and multi-annual data on abundance, body size, fecundity, hatching success and vertical distribution of C. helgolandicus. An aim was to enable comparison with its congener Calanus finmarchicus, which has been studied intensively as a key component of European and north east Atlantic marine ecosystems. C. finmarchicus is known to over-winter at depth, whereas the life-cycle of C. helgolandicus is less well understood. Overwintering populations of C. helgolandicus have been observed off the Atlantic coast between 400 and 800 m, while in the Mediterranean there is evidence of significant deep-water populations at depths as great as 4200 m. The biogeographical distribution of C. helgolandicus in European coastal waters covers a wide range of habitats, from open ocean to coastal environments, and its contribution to mesozooplankton biomass ranges from 6% to 93%. Highest abundances were recorded in the Adriatic and off the west coast of Spain. C. helgolandicus is generally found in 9-20 °C water, with maximum abundances from 13-17 °C. In contrast, C. finmarchicus is found in cooler water between 0 and 15 °C, with peak abundances from 0 to 9 °C. As water has warmed in the North Atlantic over recent decades, the range of C. helgolandicus and its abundance on the fringes of its expanding range have increased. This review will facilitate development of population models of C. helgolandicus. This will not only help answer remaining questions but will improve our ability to forecast future changes, in response to a warming climate, in the abundance and distribution of this important species.     

The state of water resources in major Mediterranean islands

This work analyses the state of water resources in six Mediterranean islands: Corsica, Crete, Cyprus, Mallorca, Malta and Sicily. The analysis is focused on the prevailing social, economic and hydroclimatological characteristics of these islands in order to identify the main common features affecting water availability, demand and use. A detailed analysis of the state of water resources in all the considered islands has been carried out. A background of current conditions relating to freshwater availability, quality and use has been established. Different strategies to face water scarcity and enhance water quality in theislands have been assessed in a context of climate change which is a common threat. The identification of similar problems for all the islands highlights the importance of strengthening inter-islands co-operation in the field of sustainable water resources management.     

Spatial distribution and vertical migrations of fish larvae communities off Northwestern Iberia sampled with LHPR and Bongo nets

The spatial distribution and diel vertical migration of fish larvae were studied in relation to the environmental conditions off NW Iberia during May 2002. Larvae from 23 families were identified, the most abundant were the Clupeidae, Gobiidae, Callionymidae, Blenniidae, Sparidae and Labridae. Sardina pilchardus was the most abundant species, mean concentrations 1 order of magnitude higher than the other fish larvae species. Larval horizontal distribution was mainly related to upwelling-driven circulation, resulting in an offshore increase of larval abundance while the vertical distribution was closely associated to the Western Iberia Buoyant Plume. Despite this general trend, taxon-specific relationships between the distribution of larvae and environmental variables were observed, and temperature was an important regressor explaining the distribution of most taxa. A comparison between ichthyoplankton samples collected alternatively with the LHPR and Bongo nets resulted in captures of larvae ≈1 order of magnitude higher for the LHPR, probably related to its higher towing speed. The spatial distribution and relative composition of larvae were also different for both nets, although the most frequent/abundant groups were the same. A fixed station sampled for 69-h showed diel vertical migrations performed by the larvae, with the highest larval concentrations occurring at surface layers during the night and most larvae being found in the neuston layer only during that period.     

Il coefficiente D'attrito interno negli strati inferiori dell'atmosfera a Mogadiscio (Periodo ottobre-febbraio)

Riassunto Utilizzando le osservazioni aerologiche fatte dalla Stazione Geofisica di Mogadiscio nell'Anno Polare 1932–33, si ricavano con il metodo di Solberg i valori del coefficiente d'attrito interno dell'aria nei diversi strati sino a 1000–1500 m., discutendone l'andamento, nei due periodi di Ottobre-Novembre e di Dicembre-Febbraio (monsone di NE). Massimi particolarmente elevati si riscontrano in Dicembre.     

The role of governance in community adaptation to climate change

The capacity to adapt to challenges such as climate change can be seen as largely determined by socioeconomic context or social vulnerability. This article examines the adaptive capacity of local actors in response to globalization and climate change, asking: how much of the desirable adaptation can be undertaken at a local level, and how much is determined by actors at other levels, for instance, when resource conflicts occur? Drawing on case studies of fishing in northern Norway and north-west Russia, the paper shows that adaptive capacity beyond the immediate economic adaptations available to local actors is, to a considerable extent, politically determined within larger governance networks.     

On the implausibility of a cometary origin for most Apollo-Amor asteroids

As the rate of replenishment of short-lived Apollo-Amor asteroids from the main belt seems to be insufficient to compensate for their losses, the idea was put forward that most of them are inactive cometary nuclei. However, the observational and theoretical evidence is inconclusive about whether it is possible to transform cometary nuclei into asteroid-like objects. There is good evidence that Apollo-Amor asteroids represent the last parent bodies of most, or even all, classes of meteorites. But meteorites cannot be formed within cometary nuclei having a constitution like Whipple's classical model, and alternative models seem to be unsatisfactory. Therefore, it is concluded that the cometary origin of most Apollo-Amor asteroids is implausible and they are genuine asteroids coming from the main belt. The process of their losses and replenishment must be studied further.