An Energy-conscious Transport Protocol for Multi-hop Wireless Networks

We present a transport protocol whose goal is to reduce power consumption without compromising delivery requirements of applications. To meet its goal of energy efficiency, our transport protocol (1) contains mechanisms to balance end-to-end vs. local retransmissions; (2) minimizes acknowledgment traffic using receiver regulated rate-based flow control combined with selected acknowledgements and in-network caching of packets; and (3) aggressively seeks to avoid any congestion-based packet loss. Within a recently developed ultra low-power multi-hop wireless network system, extensive simulations and experimental results demonstrate that our transport protocol meets its goal of preserving the energy efficiency of the underlying network.Defense Advanced Research Projects Agency (NBCHC050053

Detection of equine atypical myopathy-associated hypoglycin A in plant material: Optimisation and validation of a novel LC-MS based method without derivatisation

Hypoglycin A (HGA) toxicity, following ingestion of material from certain plants, is linked to an acquired multiple acyl-CoA dehydrogenase deficiency known as atypical myopathy, a commonly fatal form of equine rhabdomyolysis seen worldwide. Whilst some plants are known to contain this toxin, little is known about its function or the mechanisms that lead to varied HGA concentrations between plants. Consequently, reliable tools to detect this amino acid in plant samples are needed. Analytical methods for HGA detection have previously been validated for the food industry, however, these techniques rely on chemical derivatisation to obtain accurate results at low HGA concentrations. In this work, we describe and validate a novel method, without need for chemical derivatisation (accuracy = 84–94%; precision = 3–16%; reproducibility = 3–6%; mean linear range R2 = 0.999). The current limit of quantitation for HGA in plant material was halved (from 1μg/g in previous studies) to 0.5μg/g. The method was tested in Acer pseudoplatanus material and other tree and plant species. We confirm that A. pseudoplatanus is most likely the only source of HGA in trees found within European pastures

The energy spectrum observed by the AGASA experiment and the spatial distribution of the sources of ultra-high energy cosmic rays

Seven and a half years of continuous monitoring of giant air showers triggered by ultra high-energy cosmic rays have been recently summarized by the AGASA collaboration. The resulting energy spectrum indicates clearly that the cosmic ray spectrum extends well beyond the Greisen-Zatsepin-Kuzmin (GZK) cut-off at $\sim 5 \times 10^{19}$ eV. Furthermore, despite the small number statistics involved, some structure in the spectrum may be emerging. Using numerical simulations, it is demonstrated in the present work that these features are consistent with a spatial distribution of sources that follows the distribution of luminous matter in the local Universe. Therefore, from this point of view, there is no need for a second high-energy component of cosmic rays dominating the spectrum beyond the GZK cut-off.Comment: 14 pages, 4 figures, Astrophys. J. Letters (submitted

Sustavi proizvodnje u južnoj Europi: Huelva (Španjolska)

The strawberry is one of the most important crops in the Province of Huelva, south western Spain. More than 90% of the national production is harvested in this area, which means over 35% of the total production of the EU. During the 2007-2008 season, the acreage used for that crop was estimated at over 6.000 ha, and the production of 240.000 tons. The most widely used strawberry cultivar was ‘Camarosa’ (70%) followed by ‘Candonga’ (12%), with lower yields but better fruit quality, ‘Festival’ (12%), ‘Ventana’ (2%) and other minor varieties like ‘Chiflón’, ‘Aguedilla’ and ‘Coral’. The raspberry crop acreage for the 2007-2008 season has been estimated at around 1.330ha, increasing over 2.5% compared to the previous season. Most plants used to set the crop are multiplied in low elevation nurseries within the same area of the production fields, and only a small amount of plants come from high elevation nurseries in the north of Spain. The most common cultivar used is ‘Glen-Lyon’, with more than 90% of the acreage under the crop. The development of the blueberry crop in Huelva has also been important for the area during the last five years. Currently, more than 750 ha are used for the crop, but only 26 ha are in ecological production, and 90% of this acreage, is located in the village Almonte. 95% of the blueberry production is exported to Germany, United Kingdom, Belgium, the Netherlands and Switzerland. Early-season yield cultivars like ‘Misty’, ‘Sharpblue’ and ‘O`neal’ are widely used (70%) but also mid-season yield cultivars, like ‘Star’, can be found in the area. The export marketing season starts in February and lasts until June, but market picks are usually found in April, May and June. Each cultivar presents a different harvest season which period can take more than 45 days.Jagoda je jedan od najvažnijih usjeva u pokrajini Huelva, jugozapadna Španjolska. Više od 90% nacionalne proizvodnje dobiva se na tom području, što znači preko 36% ukupne proizvodnje EU. U sezoni 2997-2008. površina namijenjena tom usjevu procijenjena je na preko 6,000 ha a proizvodnja na 240.000 tona. Najviše upotrebljavan kultivar jagode bio je Camarosa (70%), a slijedili su Candonga (12%) manjih prinosa ali bolje kakvoće voća, zatim Festival (12%) Ventana (2%) te druge manje varijante kao Chiflon i Coral. Površina malina za 2007-2008 procijenjena je na oko 1.330 ha s povećanjem preko 2.5% u usporedbi s prethodnom sezonom.Većina biljaka za nasade se razmnaža u rasadnicima niskog rasta unutar područja proizvodnih nasada i samo malen broj biljaka dolazi iz rasadnika biljaka visokog rasta na sjeveru Španjolske. Najčešći kultivar je Glen-Lyon s više od 90% površina. Razvoj nasada borovnice u Helvi također je važan za to područje zadnjih pet godina.Trenutačno više od 750 ha pokriva ova kultura ali samo 26 ha je pod ekološkom proizvodnjom a 90% te površine nalazi se u selu Almonte. U Njemačku, Ujedinjeno Kraljevstvo, Belgiju, Nizozemsku i Švicarsku izvozi se 95% proizvodnje borovnica. Rani kultivari kao Misty, Sharpblue i O Neal naširoko se upogrebljavaju (70%) ali isto tako i kultivari koji dozrijevaju sredinom sezone kao Star mogu se naći u ovom području. Sezona izvoza počinje u veljači i traje do lipnja,ali branje za trgovinu obično se odvija u travnju, svibnju i lipnju.Svaki kultivar ima drugačiju sezonu branja a to razdoblje može trajati 45 dana.

Long-term Stellar Variability in the Galactic Centre Region

© 2019 The Author(s) Published by Oxford University Press on behalf of the Royal Astronomical Society.We report the detection of variable stars within a 11.5' x 11.5' region near the Galactic centre (GC) that includes the Arches and Quintuplet clusters, as revealed by the VISTA Variables in the Via Lactea (VVV) survey. There are 353 sources that show Ks-band variability, of which the large majority (81%) correspond to red giant stars, mostly in the asymptotic giant branch (AGB) phase. We analyze a population of 52 red giants with long-term trends that cannot be classified into the typical pulsating star categories. Distances and extinctions are calculated for 9 Mira variables, and we discuss the impact of the chosen extinction law on the derived distances. We also report the presence of 48 new identified young stellar object (YSO) candidates in the region.Peer reviewe

Composite mirror facets for ground based gamma ray astronomy

Composite mirrors for gamma-ray astronomy have been developed to fulfill the specifications required for the next generation of Cherenkov telescopes represented by CTA (Cherenkov Telescope Array). In addition to the basic requirements on focus and reflection efficiency, the mirrors have to be stiff, lightweight, durable and cost efficient. In this paper, the technology developed to produce such mirrors is described, as well as some tests that have been performed to validate them. It is shown that these mirrors comply with the needs of CTA, making them good candidates for use on a significant part of the array.Comment: 16 pages, 13 figures, accepted to be published on NIM