Ku & C Band solid state switch matrix for satellite payloads using LTCC multilayer substrate

This paper describes the design and development of Ku and C band solid state switch matrix for multimedia satellite payloads. The design, through the use of advanced packaging techniques, allows significant savings on mass and volume with respect to traditional electromechanical switches while guaranteeing a comparable reliability

Cytological and Ultrastructural Responses of Platanus acerifolia (Ait.) Willd. Leaves to Cerato-Platanin, a Protein from Ceratocystis fimbriata f.sp. platani

Cerato-platanin (CP) is a purified protein isolated from the culture filtrate of the ascomycete Ceratocystis fimbriata f. sp. platani (Cfp), the causal agent of canker stain disease of plane. The responses of cells/tissues of plane leaves to CP was studied by light microscopy (LM) and by transmission electron microscopy (TEM) using two experimental procedures. The most significant responses occurred already at 24 h after treatments, and were also visible at 48 h. The main effects of CP were to cause a great increase in primary starch and a certain degree of intercellular and intracellular disorganization of the spongy parenchyma cells and plasmolysis processes. In addition, an increase of intracellular phenolic compounds was observed in the palisade cells. The effects of Cfp were similar but less evident than those of CP

Non-destructive determination of floral staging in cereals using X-ray micro computed tomography (µCT)

Background Accurate floral staging is required to aid research into pollen and flower development, in particular male development. Pollen development is highly sensitive to stress and is critical for crop yields. Research into male development under environmental change is important to help target increased yields. This is hindered in monocots as the flower develops internally in the pseudostem. Floral staging studies therefore typically rely on destructive analysis, such as removal from the plant, fixation, staining and sectioning. This time-consuming analysis therefore prevents follow up studies and analysis past the point of the floral staging. Results This study focuses on using X-ray µCT scanning to allow quick and detailed non-destructive internal 3D phenotypic information to allow accurate staging of Arabidopsis thaliana L. and Barley (Hordeum vulgare L.) flowers. X-ray µCT has previously relied on fixation methods for above ground tissue, therefore two contrast agents (Lugol’s iodine and Bismuth) were observed in Arabidopsis and Barley in planta to circumvent this step. 3D models and 2D slices were generated from the X-ray µCT images providing insightful information normally only available through destructive time-consuming processes such as sectioning and microscopy. Barley growth and development was also monitored over three weeks by X-ray µCT to observe flower development in situ. By measuring spike size in the developing tillers accurate non-destructive staging at the flower and anther stages could be performed; this staging was confirmed using traditional destructive microscopic analysis. Conclusion The use of X-ray micro computed tomography (µCT) scanning of living plant tissue offers immense benefits for plant phenotyping, for successive developmental measurements and for accurate developmental timing for scientific measurements. Nevertheless, X-ray µCT remains underused in plant sciences, especially in above-ground organs, despite its unique potential in delivering detailed non-destructive internal 3D phenotypic information. This work represents a novel application of X-ray µCT that could enhance research undertaken in monocot species to enable effective non-destructive staging and developmental analysis for molecular genetic studies and to determine effects of stresses at particular growth stages

Swimming physiology of European silver eels (Anguilla anguilla L.): energetic costs and effects on sexual maturation and reproduction

The European eel migrates 5,000–6,000 km to the Sargasso Sea to reproduce. Because they venture into the ocean in a pre-pubertal state and reproduce after swimming for months, a strong interaction between swimming and sexual maturation is expected. Many swimming trials have been performed in 22 swim tunnels to elucidate their performance and the impact on maturation. European eels are able to swim long distances at a cost of 10–12 mg fat/km which is 4–6 times more efficient than salmonids. The total energy costs of reproduction correspond to 67% of the fat stores. During long distance swimming, the body composition stays the same showing that energy consumption calculations cannot be based on fat alone but need to be compensated for protein oxidation. The optimal swimming speed is 0.61–0.67 m s−1, which is ~60% higher than the generally assumed cruise speed of 0.4 m s−1 and implies that female eels may reach the Sargasso Sea within 3.5 months instead of the assumed 6 months. Swimming trials showed lipid deposition and oocyte growth, which are the first steps of sexual maturation. To investigate effects of oceanic migration on maturation, we simulated group-wise migration in a large swim-gutter with seawater. These trials showed suppressed gonadotropin expression and vitellogenesis in females, while in contrast continued sexual maturation was observed in silver males. The induction of lipid deposition in the oocytes and the inhibition of vitellogenesis by swimming in females suggest a natural sequence of events quite different from artificial maturation protocols

Synergistic Parasite-Pathogen Interactions Mediated by Host Immunity Can Drive the Collapse of Honeybee Colonies

The health of the honeybee and, indirectly, global crop production are threatened by several biotic and abiotic factors, which play a poorly defined role in the induction of widespread colony losses. Recent descriptive studies suggest that colony losses are often related to the interaction between pathogens and other stress factors, including parasites. Through an integrated analysis of the population and molecular changes associated with the collapse of honeybee colonies infested by the parasitic mite Varroa destructor, we show that this parasite can de-stabilise the within-host dynamics of Deformed wing virus (DWV), transforming a cryptic and vertically transmitted virus into a rapidly replicating killer, which attains lethal levels late in the season. The de-stabilisation of DWV infection is associated with an immunosuppression syndrome, characterized by a strong down-regulation of the transcription factor NF-κB. The centrality of NF-κB in host responses to a range of environmental challenges suggests that this transcription factor can act as a common currency underlying colony collapse that may be triggered by different causes. Our results offer an integrated account for the multifactorial origin of honeybee losses and a new framework for assessing, and possibly mitigating, the impact of environmental challenges on honeybee health

Application of Silicon-based RF IC devices in space communication systems &equipment

In the next few years,we will see the construction of systems based on constellations of medium size satellites,in which the quantity of equipment to be produced will be very large.The high production volume and compressed lead-timerequire a technology solution to achieve high integration and repeatability.This paper presents the design and performance of a highly-integrated silicon bipolar RF IC for space applications.The chip offers an Intermediate Frequency Chain,which realises two basic electrical functions:an activemixer and a broadband IF amplifier with an automatic gain control (AGC)

HTCC based Ku/IF/BB Down Converter for satellite on board processing applications

This paper presents the demonstration of an ultra compact High Temperature Cofired Ceramic (HTCC) based down converter for satellite on board processing equipment. The down converter is composed of three sections: the RF Front end in KU Band, the first IF at 400 MHz and a base-band chain at 50 MHz. The overall gain is of 90dB and the OIP3 is of 20 dBm. GaAs MMICs, Si RF-IC and ceramic saw filter have been integrated on a compact HTCC module of a size of 59x66x6 mm

GaAs, Advanced RF CMOS and Silicon Components for Miniaturised Space Digital Receiver

This paper presents the electrical and technological design for the new generation of Telemetry and Telecommand (TT&C) receivers for satellite application, in Ka Band. The congestion of the S-band are forcing towards higher frequency bands and towards a bandwidth optimization. The improvements in the system performance, and at the same time reducing cost, mass and power consumption are the goals to achieve with these new developments[1]. Performance repeatability, improved reliability figure, modular design, unit miniaturisation and reduced tuning effort in production are just few of the possible advantages introducing of latest technologies either in the RF/ microwave and in the digital domain