Embeddings of SL(2,Z) into the Cremona group

Geometric and dynamic properties of embeddings of SL(2,Z) into the Cremona group are studied. Infinitely many non-conjugate embeddings which preserve the type (i.e. which send elliptic, parabolic and hyperbolic elements onto elements of the same type) are provided. The existence of infinitely many non-conjugate elliptic, parabolic and hyperbolic embeddings is also shown. In particular, a group G of automorphisms of a smooth surface S obtained by blowing-up 10 points of the complex projective plane is given. The group G is isomorphic to SL(2,Z), preserves an elliptic curve and all its elements of infinite order are hyperbolic.Comment: to appear in Transformation Group

Robot-assisted laparoscopic surgery for treatment of urinary tract stones in children: report of a multicenter international experience

This study aimed to report a multi-institutional experience with robot-assisted laparoscopic surgery (RALS) for treatment of urinary tract stones in children. The medical records of 15 patients (12 boys), who underwent RALS for urolithiasis in 4 international centers of pediatric urology over a 5-year period, were retrospectively collected. The median patient age was 8.5 years (range 4–15). Eleven/fifteen patients (73.3%) had concurrent uretero–pelvic junction obstruction (UPJO) and 2/15 patients (13.3%) had neurogenic bladder. Stones were in the renal pelvis in 8/15 (53.3%), in the lower pole in 3/15 (20%), in the bladder in 2/15 (13.3%), and in multiple locations in 2/15 (13.3%). One patient (6.6%) had bilateral multiple kidney stones. The median stone size was 10.8 mm (range 2–30) in upper tract location and 27 mm (range 21–33) into the bladder. Eleven patients with concomitant UPJO underwent simultaneous robot-assisted pyelolithotomy and pyeloplasty in 12 kidney units. Two patients with isolated staghorn stones received robot-assisted pyelolithotomy. Robot-assisted cystolithotomy was performed in two patients with bladder stones. The median operative time was 131.8 min (range 60–240). The stone-free rate was 80% following initial surgery and 100% after secondary treatment. Clavien 2 complications (hematuria, infections) were recorded in 5/15 patients (33.3%). Three/fifteen patients (20%) with residual renal stones were successfully treated using ureterorenoscopy (Clavien 3b). RALS was a feasible, safe and effective treatment option for pediatric urolithiasis in selected cases such as large bladder stones, bilateral kidney stones, staghorn stones or concomitant anomalies such as UPJO requiring simultaneous pyeloplasty

Centrifuge rolling test for ore liquefaction analysis

To study the development of liquefaction in ore cargo, a new Rolling Test has been designed to support similar stresses than those observed in a vessel. It can be used in an 80×g macrogravity field in the 5.5m radius Ifsttar geo-centrifuge. Its main characteristics are presented

Atlas.txt : Exploring Lingusitic Grounding Techniques for Communicating Spatial Information to Blind Users

Peer reviewedPostprin

The Interaction between the Forkhead Thyroid Transcription Factor TTF-2 and the Constitutive Factor CTF/NF-1 Is Required for Efficient Hormonal Regulation of the Thyroperoxidase Gene Transcription

The forkhead thyroid-specific transcription factor TTF-2 is the main mediator of thyrotropin and insulin regulation of thyroperoxidase (TPO) gene expression. This function depends on multimerization and specific orientation of its DNA-binding site, suggesting that TTF-2 is part of a complex interaction network within the TPO promoter. This was confirmed by transfection experiments and by protein-DNA interaction studies, which demonstrated that CTF/NF1 proteins bind 10 base pairs upstream of the TTF-2- binding site to enhance its action in hormone-induced expression of the TPO gene. GST pull-down assays showed that TTF-2 physically interacts with CTF/NF1 proteins. In addition, we demonstrate that increasing the distance between both transcription factors binding sites by base pair insertion results in loss of promoter activity and in a drastic decrease on the ability of the promoter to respond to the hormones. CTF/NF1 is a family of transcription factors that contributes to constitutive and cell-type specific gene expression. Originally identified as factors implicated in the replication of adenovirus, this group of proteins (CTF/NF1-A, -B, -C, and - X) is now known to be involved in the regulation of several genes. In contrast to other reports regarding the involvement of these proteins in inducible gene expression, we show here that members of this family of transcription factors are regulated by hormones. With the use of specific CTF/NF1 DNA probes and antibodies we demonstrate that CTF/NF1-C is a thyrotropin-, cAMP-, and insulin-inducible protein. Thus CTF/NF1 proteins do not only mediate hormone-induced gene expression cooperating with TTF-2, but are themselves hormonally regulated. All these findings are clearly of important value in understanding the mechanisms governing the transcription regulation of RNA polymerase II promoters, which often contain binding sites for multiple transcription factors

Robot-assisted laparoscopic pyeloplasty (RALP) in children with horseshoe kidneys: results of a multicentric study

This multicentric study aimed to report our experience with robot-assisted laparoscopic pyeloplasty (RALP) in children with horseshoe kidney (HSK). METHODS: The records of 14 patients (11 boys and 3 girls with an average age of 9 years), who underwent RALP for repair of pelvi-ureteric junction obstruction (PUJO) in HSK in five international pediatric urology units over a 5-year period, were retrospectively reviewed. A dismembered pyeloplasty with no division of isthmus was performed in all the cases. RESULTS: The average operative time including docking was 143.5 min (range 100-205). No conversions to laparoscopy or open surgery or intra-operative complications occurred. Patients were discharged on postoperative day 2 following catheter and drain removal. The JJ stent was removed at mean 33 days postoperatively. Overall success rate was 92.8%. As for postoperative complications, we recorded a urinary tract infection (UTI) and stent-related irritative symptoms, managed with medical therapy, in two patients (II Clavien) and an anastomotic stricture in one patient needing surgical revision with no further recurrence (IIIb Clavien). At follow-up, all the patients (one after redo-surgery) reported complete resolution of symptoms, improvement of hydronephrosis on ultrasound and no residual obstruction on diuretic renogram. CONCLUSIONS: Our experience suggested that RALP in HSK is safe, feasible and with good medium-term outcomes in expert hands. An accurate pre-operative planning associated with a standardized technique is key points to achieve good surgical and functional outcomes in these challenging cases. The da Vinci robot technology offers the advantages of MIS procedures and overcomes the technical challenges of laparoscopic approach

Frequency parametrization to numerically predict flutter in turbomachinery

In the quest for performance, modern turbomachinery designs are increasingly proner to flutter hazards. Unfortunately, their prediction is currently too expensive and inaccurate for industrial purpose. A significant step towards faster methods would consist in substituting a sequential algorithm to the classical iterative ones encountered in loose coupling strategies. The approach proposed here makes it possible through the use of a meta-model taking into account the sensitivity to design variables. This parametrized method is evaluated on a standard well referenced turbine configuration