Manual on prototyping methodology and multifunctional crop rotation

This VEGINECO manual is one of a series of publications resulting from the VEGINECO project. VEGINECO specialises in producing tested and improved multi-objective farming methods for key farming practices – e.g. crop rotation, fertilisation and crop protection – to facilitate the integration of potentially conflicting objectives like economy and ecology. This report consists of two parts. The first part describes the prototyping methodology and how it was used in the VEGINECO project (Chapters 2 - 5). The second part describes the methodology for developing crop rotation strategies with examples of its application under different conditions in Europe (Chapter 6 - 11)

KALOHA: ike i ke ALOHA

A new family of channel-access schemes  called KALOHA  (for ``Knowledge in ALOHA") is introduced.  KALOHA consists of modifying the pure ALOHA  protocol  by  endowing nodes with knowledge regarding the local times when packets  and acknowledgments are received,  and sharing  estimates of channel utilization at the medium access control (MAC) layer. The only physical-layer feedback needed   in KALOHA is the reception of  correct data packets and their ACKs. A  simple Markov-chain model is used  to  compare the throughput of KALOHA with ALOHA and slotted ALOHA. The analysis takes into account the amount of knowledge that nodes have and  the  effect of  acknowledgments and turnaround latencies.  The results  demonstrate the  benefits  derived from using  and sharing knowledge of channel utilization at the MAC layer.  KALOHA is more stable  than ALOHA and attains  more than double  the throughput of  ALOHA,  without the need for carrier sensing, requiring time slotting at the physical layer, or using other physical-layer mechanisms

Fiber-based broadband wireless access employing optical frequency multiplication

Employing optical frequency multiplication, we demonstrate experimentally the simultaneous delivery of different 64QAM radio signals at 5.8 and 17.7 GHz after 4.4 km of multimode fiber in a single radio-over-fiber link. We also propose a flexible mechanism for the dynamic radio link adaptation, and the simultaneous transmission of an in-band control channel with the wireless data channels for power control purposes at the antenna site is demonstrated experimentall

La pesca deportiva de los peces de pico en Venezuela : analisis de los datos del club de playa Grande (1961-1987)

Une analyse historique de la pêche sportive des marlins et du voilier a été réalisée à partir des données de capture et d'effort du Club de la Playa Grande du littoral central du Vénézuela, qui abrite environ 50% de la flotte pratiquant cette activité. L'analyse des rendements a été menée mensuellement entre 1961 et 1987. Nous avons essayé de calculer un effort dirigé sur chacune des 3 espèces au cours de la période étudiée. La structure en taille des captures, entre 1987 et 1988, ainsi que quelques considérations sur les différentes de puissances de pêche en fonction de la participation ou non à un tournoi sont également présentée

Role of the oxygen plasma during in situ growth of YBa2Cu3O6+x thin films by pulsed laser deposition

The incorporation of oxygen into YBa2Cu3O6+x (YBaCuO) thin films during in situ growth by pulsed laser deposition (PLD) has been investigated as a function of the ablation conditions. A quenching technique has been used immediately after termination of growth to avoid any oxygen in or out-diffusion during the cooling down step. It is shown that superconducting YBaCuO thin films can be formed without any post-oxygenation procedure, contrary to what is expected from the (Image, T) thermodynamic diagram. Moreover, it is found that there is an optimal target-substrate distance, D, for each O2 deposition pressure, Image, that leads to the higher critical temperature (i.e., higher oxygenation) as well as to the best structural and morphological properties of quenched films. The results are discussed considering the formation of reactive oxygen in the laser-induced plasma during film growth