The Mars 2020 Engineering Cameras and Microphone on the Perseverance Rover: A Next-Generation Imaging System for Mars Exploration.

The Mars 2020 Perseverance rover is equipped with a next-generation engineering camera imaging system that represents an upgrade over previous Mars rover missions. These upgrades will improve the operational capabilities of the rover with an emphasis on drive planning, robotic arm operation, instrument operations, sample caching activities, and documentation of key events during entry, descent, and landing (EDL). There are a total of 16 cameras in the Perseverance engineering imaging system, including 9 cameras for surface operations and 7 cameras for EDL documentation. There are 3 types of cameras designed for surface operations: Navigation cameras (Navcams, quantity 2), Hazard Avoidance Cameras (Hazcams, quantity 6), and Cachecam (quantity 1). The Navcams will acquire color stereo images of the surface with a 96 ∘ × 73 ∘ field of view at 0.33 mrad/pixel. The Hazcams will acquire color stereo images of the surface with a 136 ∘ × 102 ∘ at 0.46 mrad/pixel. The Cachecam, a new camera type, will acquire images of Martian material inside the sample tubes during caching operations at a spatial scale of 12.5 microns/pixel. There are 5 types of EDL documentation cameras: The Parachute Uplook Cameras (PUCs, quantity 3), the Descent stage Downlook Camera (DDC, quantity 1), the Rover Uplook Camera (RUC, quantity 1), the Rover Descent Camera (RDC, quantity 1), and the Lander Vision System (LVS) Camera (LCAM, quantity 1). The PUCs are mounted on the parachute support structure and will acquire video of the parachute deployment event as part of a system to characterize parachute performance. The DDC is attached to the descent stage and pointed downward, it will characterize vehicle dynamics by capturing video of the rover as it descends from the skycrane. The rover-mounted RUC, attached to the rover and looking upward, will capture similar video of the skycrane from the vantage point of the rover and will also acquire video of the descent stage flyaway event. The RDC, attached to the rover and looking downward, will document plume dynamics by imaging the Martian surface before, during, and after rover touchdown. The LCAM, mounted to the bottom of the rover chassis and pointed downward, will acquire 90 ∘ × 90 ∘ FOV images during the parachute descent phase of EDL as input to an onboard map localization by the Lander Vision System (LVS). The rover also carries a microphone, mounted externally on the rover chassis, to capture acoustic signatures during and after EDL. The Perseverance rover launched from Earth on July 30th, 2020, and touchdown on Mars is scheduled for February 18th, 2021.

Functional results of robotic total intersphincteric resection with hand-sewn coloanal anastomosis.

BACKGROUND: In recent decades there has been an increasing trend toward sphincter-preserving procedures for the treatment of low rectal cancer. Robotic surgery is considered to be particularly beneficial when operating in the deep pelvis, where laparoscopy presents technical limitations. The aim of this study was to prospectively evaluate the functional outcomes in patients affected by rectal cancer after robotic total intersphincteric resection (ISR) with hand-sewn coloanal anastomosis. METHODS AND PROCEDURES: From March 2008 to October 2012, 23 consecutive patients affected by distal rectal adenocarcinoma underwent robotic ISR. Operative, clinical, pathological and functional data regarding continence or presence of a low anterior resection syndrome (LARS) were prospectively collected in a database. RESULTS: Twenty-three consecutive patients were included in the study: 8 men and 15 women. The mean age was 60.2 years (range 28-73). Eighteen (78.3%) had neoadjuvant radiochemotherapy. Conversion rate was nil. The mean operative time was 296.01 min and the mean postoperative hospital stay was 7.43 ± 1.73 days. According to Kirwan's incontinence score, good fecal continence was shown in 85.7% of patients (Grade 1 and 2) and none required a colostomy (Grade 4). Concerning LARS score, the results were as follows: 57.1% patients had no LARS; 19% minor LARS and 23.8% major LARS. CONCLUSIONS: Robotic total ISR for low rectal cancer is an acceptable alternative to traditional procedures. Extensive discussion with the patient about the risk of poor functional outcomes or LARS syndrome is mandatory when considering an ISR for treatment of low rectal cancer.

Robotic versus open total mesorectal excision for rectal cancer: comparative study of short and long-term outcomes.

BACKGROUND: Despite the several series in which the short-term outcomes of robotic-assisted surgery were investigated, data concerning the long-term outcomes are still scarce. METHODS: The prospectively collected records of 65 consecutive patients with extraperitoneal rectal cancer who underwent robotic total mesorectal excision (RTME) were compared with those of 109 consecutive patients treated with open surgery (OTME). Patient characteristics, pathological findings, local and systemic recurrence rates and 5-year survival rates were compared. RESULTS: There were no statistically significant differences in postoperative complications, reoperation and 30-day mortality. There were significant differences comparing groups: number of lymph nodes harvested (RTME: 20.1 vs. OTME: 14.1, P < 0.001), estimated blood loss (RTME: 0 vs. OTME: 150 ml, P = 0.003), operation time (RTME: 299.0 vs. OTME: 207.5 min, P < 0.001) and length of postoperative stay (RTME: 6 vs. OTME: 9 days, P < 0.001). The rate of circumferential resection margin involvement and distal resection margin were not statistically different between groups. There were no statistically significant differences at the 5-year follow-up: overall survival, disease-free survival and cancer-specific survival. The cumulative local recurrence rate was statistically lower in the robotic group (RTME: 3.4% vs. OTME: 16.1%, P = 0.024). CONCLUSION: RTME showed a significant reduction in local recurrence rate and a higher, although not statistically significant, long-term cancer-specific survival with respect to OTME. Prospective randomized studies are needed to confirm or deny significantly better local control rates with robotic surgery.

Molecular phylogenetics and historical biogeography of the west-palearctic common toads (Bufo bufo species complex).

In most pan-Eurasiatic species complexes, two phenomena have been traditionally considered key processes of their cladogenesis and biogeography. First, it is hypothesized that the origin and development of the Central Asian Deserts generated a biogeographic barrier that fragmented past continuous distributions in Eastern and Western domains. Second, Pleistocene glaciations have been proposed as the main process driving the regional diversification within each of these domains. The European common toad and its closest relatives provide an interesting opportunity to examine the relative contributions of these paleogeographic and paleoclimatic events to the phylogeny and biogeography of a widespread Eurasiatic group. We investigate this issue by applying a multiproxy approach combining information from molecular phylogenies, a multiple correspondence analysis of allozyme data and species distribution models. Our study includes 304 specimens from 164 populations, covering most of the distributional range of the Bufo bufo species complex in the Western Palearctic. The phylogenies (ML and Bayesian analyses) were based on a total of 1988 bp of mitochondrial DNA encompassing three genes (tRNAval, 16S and ND1). A dataset with 173 species of the family Bufonidae was assembled to estimate the separation of the two pan-Eurasiatic species complexes of Bufo and to date the main biogeographic events within the Bufo bufo species complex. The allozyme study included sixteen protein systems, corresponding to 21 presumptive loci. Finally, the distribution models were based on maximum entropy. Our distribution models show that Eastern and Western species complexes are greatly isolated by the Central Asian Deserts, and our dating estimates place this divergence during the Middle Miocene, a moment in which different sources of evidence document a major upturn of the aridification rate of Central Asia. This climate-driven process likely separated the Eastern and Western species. At the level of the Western Palearctic, our dating estimates place most of the deepest phylogenetic structure before the Pleistocene, indicating that Pleistocene glaciations did not have a major role in splitting the major lineages. At a shallow level, the glacial dynamics contributed unevenly to the genetic structuring of populations, with a strong influence in the European-Caucasian populations, and a more relaxed effect in the Iberian populations.

Impact on survival of the number of lymph nodes removed in patients with node-negative gastric cancer submitted to extended lymph node dissection.

PURPOSE: This study was designed to establish whether the number of lymph nodes removed has an effect on prognosis in patients with node-negative gastric cancer. PATIENTS AND METHODS: We retrospectively analysed data of 114 consecutive patients who underwent gastrectomy and extended lymph node dissection for node-negative adenocarcinoma of the stomach between 2000 and 2005. Standard survival methods and restricted cubic spline multivariable Cox regression models were applied. RESULTS: Median age was 63 years and 67 patients out of 114 (59%) were males. Median number of dissected LNs was 22 (range 2-73). Median follow-up was 76 months. Patients who had ≤15 nodes removed had significantly worse distant disease-free survival, disease-free survival and overall survival at multivariable analysis than other patients. The results did not change when pT1 and pT2-3 cancer patients were analysed separately. The risk of distant metastases decreased as the number of dissected lymph nodes increased (>15). CONCLUSIONS: More extended lymph node resection offered survival benefit even in the subgroup of patients with early stage disease. Lymphadenectomy involving more than 15 lymph nodes should be performed for the treatment of node-negative gastric cancer. SYNOPSIS: The impact on survival of the number of lymph nodes removed in patients with node-negative gastric cancer has not been established. This study suggests that more extended lymph node resection offers protection, as patients who had ≤15 nodes removed had significantly worse disease-free survival and overall survival at multivariate analysis than patients in whom >15 nodes were removed.

An aerosol-based route to nanostructured powders synthesis in liquids.

An alternative technique for synthesizing nanostructured powders in liquid solutions has been developed. The technique combines generation of charged aerosols via electrospray with reductive precipitation reactions in liquids. Electrospray of liquids is carried out to produce micrometric, nearly mono-dispersed airborne droplets from a precursor solution. The droplets, which are spatially separated due to electrostatic repulsion, are collected in a bath containing a reductive solution. The effect of some process parameters on the resulting material texture has been studied. Tin particles produced from tin chloride solutions are regarded as a model here, but it is stressed that this approach can be considered as a general method to synthesize many other metallic-like materials, such as alloys and intermetallics. Hence, the large variety of materials that can be produced in this way could find several relevant applications in different technological fields.

Sol-gel and hard template assisted synthesis of 3D nanostructured SnO2 electrodes.

Self-standing tubular-like structures of nano-crystalline SnO2 with controlled diameter and length (200 nm x 10 microm) have been synthesized by sol-gel process in combination with a hard template. Different textures can be easily achieved-from hollow tubes to quasi-solid rods-by simply tuning the initial concentration of the precursor oxide gel and the dipping time of the template. Moreover, these self-supported SnO2 structures have been turned into 3D nanostructured electrodes directly fabricated on copper substrates. The enhanced electrochemical properties of these hierarchical nano-architectures are promising for applications in Li-ion batteries negative electrodes.

[Blunt trauma of hepatic ducts: a difficult diagnostic-therapeutic approach]. / I traumi chiusi dei dotti epatici: un difficile inquadramento diagnostico-terapeutico.

Traumatic injuries of left and right hepatic ducts are rare, with about 40 cases reported in literature. Preoperative diagnosis is difficult, so that up to 40% of lesions may be undetected at laparotomy. Prompt diagnosis could preserve by high morbidity rate of such injuries. The extremely widespread and routine use of ERCP as well as intraoperative cholangiography may allow reducing dramatically the diagnostic time lag and the percentage of lesions formerly undetected by laparotomy. Therapeutic options are extremely variable. On the basis of the experiences reported for the treatment of iatrogenic lesions of the biliary tract, reconstruction by jejunal Roux-en-Y loop biliodigestive anastomosis is preferred, whenever lacerations of an hepatic duct appear to be complete or nearly so, on account of the high incidence of stenosis and late complications, detected in case of termino-terminal direct biliary anastomosis. However, in selected cases, when the transection appear neat and simple, an end-to-end anastomosis could be performed with low risk. Mortality after blunt biliary duct injury represents nowadays a rare event at least in patients presenting without severe associated traumatic lesions, so that the clinical attention has been progressively focused on the relatively high rate of postoperative complications. These adverse events are often extremely demanding in terms of prolongation of hospital stay, need for multiple invasive procedures and overall costs of patient's management.

Mass - movement and tectonics

Tectonics exerts a strong control on mass - movement development. This control may be either direct or indirect. Build - up of relief energy and modification of the gravity stress field (either on short or long - terms) are the most important direct ways through which geodynamic processes lead to mass movement. River down - cutting consequent to up - lifting and folding, pervasive shearing of rocks, modification of attitude of structural discontinuities, outcropping of weak rock levels, are the indirect ways. Mas - movement, in its turn, is able to generate structural features in several aspects equivalent to tectonic ones. (AU)