385 research outputs found
Emission of multiple dispersive waves from a single Raman-shifting soliton in an axially-varying optical fiber
International audienceWe provide the experimental demonstration of the generation of multiple dispersive waves from a single soliton propagating in the vicinity of the first zero-dispersion wavelength of an axially-varying optical fiber. The fiber is designed such that the Raman-shifting soliton successively hits three times the longitudinally evolving zero-dispersion wavelength, which results in the emission of three distinct dispersive waves at different fiber lengths. These results illustrate how suitably controlled axially-varying fibers allow to tailor the soliton dynamics in a very accurate way
Development of Micromorph Cells in Large-Area Industrial Reactor
The influences of the deposition pressure and silane depletion on the efficiency of single-junction microcrystalline silicon solar cells has been investigated. The efficiency is found to correlate with the ion energy which affects the density of states in the absorber material. Cell with efficiency of 7.3% at a deposition rate of 1 nm/s, and, respectively, 7.8% at 0.35 nm/s were deposited in R&D KAI M industrial reactor. Silicon oxide based intermediate reflector layers were developed in KAI reactor for incorporation in micromorph devices. Material with an index of refraction of 1.7 at 600 nm and low lateral conductivity were deposited. Micromorph devices incorporating these intermediate reflector layers were fabricated with initial efficiency of 12.3% at a deposition rate of 0.35 nm/s and 10.8% at 1 nm/s
Micromorph tandem solar cells grown at high rate with in-situ intermediate reflector in industrial KAI PECVD reactors
We report on the latest results of tandem micromorph (a-Si:H/μc-Si:H) silicon solar cells fabricated in commercial Oerlikon Solar KAI-S and KAI-M PECVD reactors. First developments of in-situ silicon oxide based intermediate reflector (SOIR) in KAI reactors are as well presented. Under low depletion conditions (silane concentration 1cm2, with a deposition rate of 0.55 nm/s for microcrystalline silicon and an ex-situ silicon oxide-based intermediate reflector (SOIR). Under high depletion conditions, the growth rate could be raised up to 1.2 nm/s, in a modified KAI-M reactor, and the highest initial efficiency reached so far is 9.7% with in-situ SOIR and top cell thickness of ∼ 230 nm. Promising micromorph solar cells are thus produced under conditions that are highly favorable to low-cost fabrication of tandem modules at an industrial level
Climate Influence on Deep Sea Populations
Dynamics of biological processes on the deep-sea floor are traditionally thought to be controlled by vertical sinking of particles from the euphotic zone at a seasonal scale. However, little is known about the influence of lateral particle transport from continental margins to deep-sea ecosystems. To address this question, we report here how the formation of dense shelf waters and their subsequent downslope cascade, a climate induced phenomenon, affects the population of the deep-sea shrimp Aristeus antennatus. We found evidence that strong currents associated with intense cascading events correlates with the disappearance of this species from its fishing grounds, producing a temporary fishery collapse. Despite this initial negative effect, landings increase between 3 and 5 years after these major events, preceded by an increase of juveniles. The transport of particulate organic matter associated with cascading appears to enhance the recruitment of this deep-sea living resource, apparently mitigating the general trend of overexploitation. Because cascade of dense water from continental shelves is a global phenomenon, we anticipate that its influence on deep-sea ecosystems and fisheries worldwide should be larger than previously thought
Selecting ecosystem indicators for fisheries targeting highly migratory species: An EU project to advance the operationalization of the EAFM in ICCAT and IOTC
Several international legal agreements and guidelines have set the minimum standards and key principles to guide the implementation of an
ecosystem approach to fisheries management (EAFM). However, the implementation of an EAFM in tuna Regional Fisheries Management
Organizations (RFMOs) has been patchy and lack a long-term plan, vision and guidance on how to operationalize it. The Specific Contract N0
2 “selecting ecosystem indicators for fisheries targeting highly migratory species-” (SC02 project) under the Framework Contract - EASME/
EMFF/2016/008 provisions of Scientific Advice for Fisheries Beyond EU Waters- addresses several scientific challenges and provides insights
to support the implementation of an EAFM through collaboration and consultation with the International Commission for the Conservation of
Atlantic Tunas (ICCAT) and the Indian Ocean Tuna Commission (IOTC). Specifically, this project first highlights properties of success and best
practices from other regions of the world in operationalizing the ecosystem approach that potentially could be transferred to ICCAT and IOTC.
Second, it delivered a list of potential ecosystem indicators of relevance to tuna RFMOs (ICCAT and IOTC) that are suitable to track the
impacts of fisheries targeting tuna and tuna-like species on the broader pelagic ecosystem. Third, it designed a general framework based on a
rule-based decision tree to provide guidance on how reference points could be set and used for diverse types of ecosystem indicators. Fourth,
it proposed candidate ecoregions within the Atlantic and Indian Oceans which could be used to guide region-based ecosystem plans,
assessments and research to ultimately provide better ecosystem-based advice to inform fisheries management. Fifth, it developed two pilot
ecosystem plans for two case study regions, the tropical ecoregion within the ICCAT convention area, and the temperate ecoregion within the
IOTC convention area. At this stage, these pilot ecosystem plans aim to create awareness about the need for ecosystem planning, start a
discussion about the elements that need to be part of a planning process, and initiate a discussion in ICCAT and IOTC about the potential
needs of ecosystem plans and their function. Finally, this project provided recommendations to foster the potential development, use, and
implementation of ecosystem plans in ICCAT and IOTC
Digital reconstruction of the inner ear of Leptictidium auderiense (Leptictida, Mammalia) and North American leptictids reveals new insight into leptictidan locomotor agility
Leptictida are basal Paleocene to Oligocene eutherians from Europe and North America comprising species with highly specialized postcranial features including elongated hind limbs. Among them, the European Leptictidium was probably a bipedal runner or jumper. Because the semicircular canals of the inner ear are involved in detecting angular acceleration of the head, their morphometry can be used as a proxy to elucidate the agility in fossil mammals. Here we provide the first insight into inner ear anatomy and morphometry of Leptictida based on high-resolution computed tomography of a new specimen of Leptictidium auderiense from the middle Eocene Messel Pit (Germany) and specimens of the North American Leptictis and Palaeictops. The general morphology of the bony labyrinth reveals several plesiomorphic mammalian features, such as a secondary crus commune. Leptictidium is derived from the leptictidan groundplan in lacking the secondary bony lamina and having proportionally larger semicircular canals than the leptictids under study. Our estimations reveal that Leptictidium was a very agile animal with agility score values (4.6 and 5.5, respectively) comparable to Macroscelidea and extant bipedal saltatory placentals. Leptictis and Palaeictops have lower agility scores (3.4 to 4.1), which correspond to the more generalized types of locomotion (e.g., terrestrial, cursorial) of most extant mammals. In contrast, the angular velocity magnitude predicted from semicircular canal angles supports a conflicting pattern of agility among leptictidans, but the significance of these differences might be challenged when more is known about intraspecific variation and the pattern of semicircular canal angles in non-primate mammals
The Evolution of Bat Vestibular Systems in the Face of Potential Antagonistic Selection Pressures for Flight and Echolocation
PMCID: PMC3634842This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited
Abdominal wall paresis as a complication of laparoscopic surgery
Purpose: Abdominal wall nerve injury as a result of trocar placement for laparoscopic surgery is rare. We intend to discuss causes of abdominal wall paresis as well as relevant anatomy. Methods: A review of the nerve supply of the abdominal wall is illustrated with a rare case of a patient presenting with paresis of the internal oblique muscle due to a trocar lesion of the right iliohypogastric nerve after laparoscopic appendectomy. Results: Trocar placement in the upper lateral abdomen can damage the subcostal nerve (Th12), caudal intercostal nerves (Th7-11) and ventral rami of the thoracic nerves (Th7-12). Trocar placement in the lower abdomen can damage the ilioinguinal (L1 or L2) and iliohypogastric nerves (Th12-L1). Pareses of abdominal muscles due to trocar placement are rare due to overlap in innervation and relatively small sizes of trocar incisions. Conclusion: Knowledge of the anatomy of the abdominal wall is mandatory in order to avoid the injury of important structures during trocar placement
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