Spatial and temporal dynamics of suspended load at-a-cross-section: the lowermost Ebro River (Catalonia, Spain)

Suspended load dynamics were analyzed for the period 2007-2009 in a semi-meandering cross-section under different hydrological conditions. Samples were collected at four different points of the cross-section. During “low discharges” (≤600 m³/s) suspended load samples were collected at-a-monthly basis, whereas at “high discharges” (>600 m³/s) sampling was conducted intensively (at-a-daily basis during the first stages of the flood event). Results indicated that during low discharges, both organic and inorganic suspended load concentrations tended to be uniformly distributed across the fluvial section; but during high discharges, two distinct areas were found: an area extending from the “Inner-bank” to the “Channel centre” (Area-I) with higher suspended concentrations (organic and inorganic) than those recorded in the “Outer bank” (Area-II). This phenomenon was likely related to the formation of secondary flow velocity cells and the activation of new sources of sediment. In addition, a non-significant relationship between organic suspended load and water flow was observed in the outer-bank. At-a-monthly basis, the analysis of the suspended load showed the existence of an intra-annual cycle of the inorganic concentrations, with a progressive increase from October to March followed by a decrease from March to September. Nevertheless, the organic suspended load did not show any trend, being equally distributed along the year, suggesting that other sources of organic matter besides phytoplankton are predominant.     

FPGA solution for matrix converter double sided space vector modulation algorithm

Matrix Converters (MCs) present several advantages, but yet several barriers must be overcome, such as MC modulation and control technique complexity. This article proposes a multiplatform environment that allows the implementation of the Double Sided Space Vector Modulation (DS-SVM) algorithm in a last-generation Field Programmable Gate Array (FPGA) device. The traditional digital control architecture, based on a SP and some additional devices, is improved by means of a last generation FPGA where the main processor (PowerPC), internal memory, communication interfaces, I/O capabilities and a hardware core that executes the DS-SVM have been connected using on-chip buses. The methodology begins by defining the DS-SVM in a Matlab-Simulink environment. The PowerPC delivers 680 MIPS, but it is not a good candidate to execute the DS-SVM algorithm because it is not possible to achieve the modulation frequency that is necessary for an MC. A new configurable hardware circuit that implements the whole DS-SVM algorithm is proposed. This solution achieves modulation frequencies over 100 kHz. This hardware core is connected to one of the PowerPC buses and the processor can configure it or get feedback information at any time. As the processor is liberated from the very time-consuming DS-SVM computation, it can execute many higher level tasks.     

Real-Time Imaging with Frequency Scanning Array Antenna for Industrial Inspection Applications at W band

A real-time imaging system based on a frequency scanning antenna for conveyor belt setups is presented in this paper. The frequency scanning antenna together with an inexpensive parabolic reflector operates at the W band enabling the detection of details with dimensions in the order of 2 mm. In addition, a low level of sidelobes is achieved by optimizing unequal dividers to window the power distribution for sidelobe reduction. Furthermore, the quality of the images is enhanced by the radiation pattern properties. The performance of the system is validated by showing simulation as well as experimental results obtained in real time, proving the feasibility of these kinds of frequency scanning antennas for cost-effective imaging applications.     

Changes on publishing behavior in response to research policy guidelines. The case of the Spanish Research Council in the field of agronomy

The aim of this study is to identify changes in publishing behavior of Spanish scientists belonging to the Area of Agronomy of the Spanish Research Council (CSIC), in response to scientific policy actions carried out in Spain. For this purpose, we analyze Spanish scientific output published in Spanish journals (covered by the ICYT database), as well as in international journals (covered by theScience Citation Index), during the period 1980–1995. Congress and conference publications, books and monographs, are also considered. The following changes in publication habits have been noticed: migration of works towards SCI journals and increased use of books and monographs as channel of publication of research works. A decreasing participation of Spanish researchers in scientific meetings has also been noticed, especially since 1989.     

Prenatal diagnosis of biliary atresia associated with choledochal cyst

We report a case of biliary atresia promptly detected by its association with a choledochal cyst, prenatally diagnosed at 20 weeks' gestation. The baby was operated at 14 days of life. A choledochal cyst was found and fibrosis of the extrahepatic bile ducts was also noted. So, excision of the choledochal cyst and a Roux-en-Y porto-jejunostomy was done. Nine months later, despite an appropriate biliary drainage, echographic and histological changes compatible with liver cirrhosis have been detected. Including this one, six cases have been reported.     

Complementary and overlapping expression of glial cell line-derived neurotrophic factor (GDNF), c-ret proto-oncogene, and GDNF receptor-alpha indicates multiple mechanisms of trophic actions in the adult rat CNS

Glial cell line-derived neurotrophic factor (GDNF), the most potent trophic factor yet described for both dopaminergic neurons of the substantia nigra and spinal motorneurons, has recently been shown to signal through a multireceptor complex composed of a novel glycosylphosphatidylinositol-anchored GDNF receptor-alpha (GDNFR-alpha) and the receptor tyrosine kinase product of the c-ret proto-oncogene (RET). Despite its importance, the individual expression patterns and the relationships between domains of expression of the different components of this trophic system are not understood. We show here by in situ hybridization that GDNF mRNA is expressed in the normal adult rat brain in several targets of substantia nigra neurons, including striatum, nucleus accumbens, thalamic nuclei, olfactory tubercle, hippocampus, cerebellum, and cingulate cortex as well as in the internal granular cell layer of the olfactory bulb. Within the basal ganglia we observe a pronounced segregation of regions expressing GDNF from those expressing GDNF receptors, suggesting that within these structures GDNF is functioning in its anticipated role as a target-derived trophic factor. In addition, the expression of GDNF and both GDNF receptors within the cerebellum, hippocampus, and olfactory bulb may indicate a paracrine mode of action. Importantly, we also see expression of RET mRNA in cellular populations within the cerebellum and the glomerular layer of the olfactory bulb, as well as in the subthalamic nucleus, which lack GDNFR-alpha expression, indicating that RET functions either independently of GDNFR-alpha or with GDNFR-alpha presented in trans. Conversely, GDNFR-alpha is widely expressed in many regions in which RET expression is absent, suggesting that GDNFR-alpha may associate with additional signaling receptors. Finally, RET and GDNFR-alpha show distinct patterns of regulated expression in the brain after kainic acid stimulation and in the sciatic nerve after nerve transection. Taken together these findings indicate that GDNF, RET, and GDNFR-alpha utilize multiple mechanisms to comprise physiologically relevant trophic circuits for different neuronal populations.     

Unilateral neonatal cystic disease of the kidney as first manifestation of tuberous sclerosis]

Traumatic optic neuropathy (TON) causes blindness of varied severity and occurs infrequently as a complication of closed head injury. A case is presented of TON that occurred in a patient who suffered complete T4 paraplegia from a motorcycle accident but in whom no severe head injury took place. In this case, high-dose intravenous methylprednisolone was begun for the spinal cord injury and repeated 24 hours later for the TON. Vision improved from near total blindness to 20/400 in the left eye (OS) and 20/130 in the right eye (OD). Two weeks later, however, the patient's vision suddenly worsened. Magnetic resonance imaging (MRI) using fat suppression confirmed a lesion along the optic nerve consistent with TON. A third course of methylprednisolone again led to improved vision. The steroids were then tapered orally over 2 weeks and the patient had no further relapses. Moderate to severely impaired vision of 20/ 400 OS and 20/130 OD continues to interfere with the patient's function and spinal cord rehabilitation program. It was concluded that a steroid taper was important in maintaining initial visual gains in this case. Awareness of TON and careful attention to the patient's clinical course can minimize deficit and maximize functional outcomes.