Simulating and Designing RF Transmitter for Small Satellites

This paper discusses the simulation and the design of an RF transmitter for small satellites operating in the commercial S- band (2.2 - 2.29 GHz) with a data rate of 8Mbps. In such systems, modelling frequency-dependent nonlinear characteristics of complex analog blocks and subsystems is critical for enabling efficient verification of mixed-signal system designs. In order to provide efficient and accurate simulation for the transmitter circuits, simple macromodels for weakly nonlinear mixer and power amplifier are used in the system simulation. Also, we introduce the noise in several circuits (frequency synthesizer, crystal oscillator, power amplifier, mixer,…) and we demonstrate their effect on the noise performance system. In the simulation we consider features of components and technologies commercially available

Kite Generator System Periodic Motion Planning Via Virtual Constraints

International audienceThis paper presents a new control strategy for Kite Generator System (KGS). The proposed feedback strategy is based on motion planning using the virtual constraint approach and ensures exponential orbital stability of the desired trajectory. The strategy is detailed, applied and tested via numerical simulations and showed good convergence to a desired periodic motion

Effect of stripe clearing on 4 grasses species and 2 broadleaves of caldenal

En la Región del Espinal, Distrito del Caldén, en la provincia de San Luis existe un fuerte proceso de agriculturización con la consecuente pérdida de remanentes de bosque nativo, peligro de conservación de especies nativas e invasión de especies exóticas. El objetivo del presente trabajo fue evaluar el efecto del desmonte en franjas sobre 6 especies del caldenal (4 gramíneas y 2 latifoliadas). El estudio se realizó en un campo a 15 km. al norte de la ciudad de Villa Mercedes (San Luis), sometido a un desmonte en franjas para uso agrícola en el año 2003. En 5 sitios ubicados en franjas remanentes de bosque nativo y 5 en bosque nativo sin desmonte, se trazaron transectas de 39 m de longitud, dirección NS y a lo largo de la misma se registraron las especies presentes en 14 unidades de muestreo de 1 m2. Los datos se analizaron utilizando IBM SPSS Statistics 19, mediante Métodos No Paramétricos, U de Mann-Whitney. El análisis estadístico mostró diferencias significativas (p<0.05) en Digitaria californica, Pappophorum pappiferum, Salsola kali y Cestrum parqui. El estudio demostró que el cultivo entre franjas de bosque nativo produjo un cambio en la frecuencia de poáceas nativas y de latifoliadas.In the region of “Espinal”, Calden Distrct in the province of San Luis there is a strong agriculturization process with the consequent loss of native forest remnants, conserving endangered native species and invasion of exotic species. The aim of this study was to evaluate the effect of the stripe clearing on 6 species of caldenal (4 grasses and 2 broa- dleaves). The study was conducted in a field 15 km to the north of the city of Villa Mercedes (San Luis), subjected to a strip-clearing for agricultural use, in the year 2003. On 5 sites into native forest remnants stripes and 5 into without clearing native forest, 39 m long tran- sects were laid, N-S direction, and along the same were recorded the presente species in 14 sampling units of 1 m2. Data were analyzed by IBM SPSS Statistics 19, through non- parametric methods, Mann-Whitney U. Statistical analysis showed significant differences (p <0.05) in Digitaria californica, Pappophorum pappiferum, Salsola kali and Cestrum par- qui. The study showed that the cultivation of native forest between stripes was a change in the frequency of native grasses and broadleaves.Fil: Ruiz, O. M.. Universidad Nacional de San Luis; Argentina;Fil: Luna, H. R.. Universidad Nacional de San Luis; Argentina;Fil: Bacha, Emmanuel Fernando. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico - CONICET - San Luis; Argentina; Universidad Nacional de San Luis; Argentina;Fil: Pedranzani, H.. Universidad Nacional de San Luis; Argentina;Fil: Gabutti, E.G.. Universidad Nacional de San Luis; Argentina

Perventricular device closure of muscular ventricular septal defects on the beating heart: technique and results

AbstractObjectiveBoth surgical management and percutaneous device closure of muscular ventricular septal defects have drawbacks and limitations. This report describes our initial experience with intraoperative device closure of muscular ventricular septal defects without cardiopulmonary bypass in 6 consecutive patients.MethodsA median sternotomy or a subxiphoid minimally invasive incision was performed. Under continuous transesophageal echocardiographic guidance, the right ventricle free wall was punctured, and a wire was introduced across the largest defect. The Amplatzer (AGA Medical Corporation, Golden Valley, Minn) muscular ventricular septal defect occluding device (a self-expandable double-disk device) was used. An introducer sheath was fed over the wire, with the sheath tip positioned in the left ventricle cavity. The device was then advanced inside the sheath and deployed by retracting the sheath. Associated cardiac lesions, if any, can then be repaired during cardiopulmonary bypass. A similar technique can also be applied for periatrial closure of complex atrial septal defects.ResultsThe initial 6 patients are presented. Cardiopulmonary bypass was not needed in any patient for placement of the device and needed in 4 patients for repair of concomitant malformations only (double-outlet right ventricle, aortic arch hypoplasia, pulmonary artery band removal). No complications from using this technique occurred. Discharge echocardiograms showed no significant shunting across the ventricular septum.ConclusionsPerventricular closure of multiple muscular ventricular septal defects is safe and effective. We believe that this could become the treatment of choice for any infant with muscular ventricular septal defects or any child with muscular ventricular septal defect and associated cardiac defects

Genetic engineering of apple (Malus domestica Borkh.) for resistance to fungal diseases using g2ps1 gene from Gerbera hybrida (Asteraceae)

In the present study, g2ps1 gene from Gerbera hybrida coding for 2-pyrone synthase which contribute for fungal and insect resistance was used. The aim was to work out an efficient approach of genetic transformation for apple cvs. ‘Golden Delicious’, ‘Royal Gala’ and ‘MM111’, ‘M26’ rootstocks for improving their fungal resistance using genetic engineering techniques. Adventitious shoot formation from leaf pieces of apples studied was achieved using middle leaf segments taken from the youngest leaves from in vitro-grown plants.Optimum conditions for ‚direct’ shoot organogenesis resulted in high regeneration efficiency of&nbsp; 0%, 95%, 92%, 94% in the studied apples respectively. Putative transgenic shoots could be obtained on MS media with B5 Vitamins, 5.0 mg l-1 BAP, or 2.0 mg l-1 TDZ with 0.2 mg l-1 NAA in the presence of the selection agent “PPT” at 3.0-5.0 mgl-1. Shoot multiplication of transgenic shoots was achieved on: MS + B5 vitamins + 1.0 mg l-1 BAP + 0.3 mg l-1 IBA, 0.2 mg l-1 GA3+1.0 g/l MES+ 30 g/l sucrose + 7.0 g/l Agar, with the selection agent PPT at 5.0 mg l-1 and were subcultured every 4 weeks in order to get sufficient material to confirm transformation of the putative shoots obtained. Six, seven, one and six transgenic clones of the apples studied respectively have been obtained and confirmed by selection on the media containing the selection agent “PPT” and by PCR analysis using the suitable primers in all clones obtained for the presence of the selection” bar gene (447 bp) and the gene-of- interest “g2PS1” (1244 bp), with transformation efficiency of 0.4%, 0.6%, 0.1% and 0.3% respectively. These transgenic clones were multiplied further in vitro in the presence of the selection agent ‘PPT’ and rooted in vitro. Rooted transgenic plantlets were successfully acclimatized and are being kept under-containment conditions according to the biosafety by-law in Syria to evaluate their performance for fungal resistance

Genetic engineering of apple (Malus domestica Borkh.) for resistance to fungal diseases using g2ps1 gene from Gerbera hybrida (Asteraceae)

In the present study, g2ps1 gene from Gerbera hybrida coding for 2-pyrone synthase which contribute for fungal and insectresistance was used. The aim was to work out an efficient approach of genetic transformation for apple cvs. ‘Golden Delicious’, ‘Royal Gala’and ‘MM111’, ‘M26’ rootstocks for improving their fungal resistance using genetic engineering techniques. Adventitious shoot formationfrom leaf pieces of apples studied was achieved using middle leaf segments taken from the youngest leaves from in vitro-grown plants.Optimum conditions for ‚direct’ shoot organogenesis resulted in high regeneration efficiency of 90%,95%,92%,94% in the studied applesrespectively. Putative transgenic shoots could be obtained on MS media with B5 Vitamins, 5.0 mg l-1 BAP, or 2.0 mg l-1 TDZ with 0.2 mg l-1NAA in the presence of the selection agent “PPT” at 3.0-5.0 mgl-1. Shoot multiplication of transgenic shoots was achieved on: MS + B5vitamins + 1.0 mg l-1 BAP + 0.3 mg l-1 IBA, 0.2 mg l-1 GA3+1.0 g/l MES+ 30 g/l sucrose + 7.0 g/l Agar, with the selection agent PPT at 5.0mg l-1 and were subcultured every 4 weeks in order to get sufficient material to confirm transformation of the putative shoots obtained. Six,seven, one and six transgenic clones of the apples studied respectively have been obtained and confirmed by selection on the media containingthe selection agent “PPT” and by PCR analysis using the suitable primers in all clones obtained for the presence of the selection” bar gene(447 bp) and the gene-of- interest “g2PS1” (1244 bp), with transformation efficiency of 0.4%, 0.6%, 0.1% and 0.3% respectively. Thesetransgenic clones were multiplied further in vitro in the presence of the selection agent ‘PPT’ and rooted in vitro. Rooted transgenic plantletswere successfully acclimatized and are being kept under-containment conditions according to the biosafety by-law in Syria to evaluate theirperformance for fungal resistance