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Background The primary limitation of telesurgery is the communication latency. Accurate and detailed data are lacking to reveal the latency effects on surgical performance; furthermore, the maximum acceptable latency in telesurgery remains unclear. Methods Sixteen medical students performed an energy dissection exercise and a needle-driving exercise on the robotic simulator dV-Trainer ® , and latencies varying between 0 and 1,000 ms with a 100-ms interval were randomly and blindly presented. Task completion time, instrument motion, and errors were automatically recorded. The difficulty, security, precision, and fluidity of manipulation were self-scored by subjects between 0 and 4 (0 the best, 2 moderate, and 4 the worst). Results Task completion time, motion, and errors increased gradually as latency increased. An exponential regression was fit to the mean times and motions ( R 2  > 0.98). Subjective scorings of the four items were similar. The mean scores were less than 1 at delays ≤200 ms, then increased from 1 to 2 at 300–700 ms, and finally approached 3 at delays above. In both exercises, latencies ≤300 ms were judged to be safe by all and 400–500 ms were accepted by 66–75 % of subjects. Less than 20 % of subjects accepted delays ≥800 ms. Conclusions The surgical performance deteriorates in an exponential way as the latency increases. The delay impact on instrument manipulation is mild at 0–200 ms, then increases from small to large at 300–700 ms, and finally becomes very large at 800–1,000 ms. Latencies ≤200 ms are ideal for telesurgery; 300 ms is also suitable; 400–500 ms may be acceptable but are already tiring; and 600–700 ms are difficult to deal with and only acceptable for low risk and simple procedures. Surgery is quite difficult at 800–1,000 ms, telementoring would be a better choice in this case.

The prevalent mode of reproduction among ants is arrhenotokous parthenogenesis where unfertilized eggs give rise to haploid males and fertilized eggs develop into diploid females. Some ant species are capable of thelytokous parthenogenesis, a type of asexual reproduction where females develop from unfertilized diploid eggs. Thelytoky is well-documented in more than 20 ant species. Cytogenetic data are available for six species demonstrating that some thelytokous ant species are capable of producing males occasionally as well as maintaining their chromosome numbers and proper chromosome pairings. Mycocepurus smithii is a thelytokous fungus-growing ant species that inhabits large parts of Central and South America. Cytogenetic data are unavailable for M. smithii and male individuals were never documented for this species, although the presence of males is expected because genetic recombination was observed in a few sexually reproducing populations in Brazil and haploid sperm was documented from the spermathecae of M. smithii queens. This study aims at comparatively studying asexual and sexual populations of M. smithii using classical and molecular cytogenetic methods to test whether karyotype configuration is modified according to the mode of reproduction in M. smithii . Moreover, we report the discovery of M. smithii males from a sexually reproducing population in the Brazilian state Pará, diagnose the male of M. smithii , and morphologically characterize their spermatozoa. Karyotypic variation was observed within the asexual population (2n = 9, 10, or 11), whereas the chromosome number was fixed in the sexual population (2n = 14, n = 7). Identical karyotypes were maintained within individual M. smithii colonies and karyotype variation was only observed between colonies. In asexual individuals, the karyomorphs showed a decay of homologous chromosome pairs, especially in individuals with the karyomorph 2n = 11, which is potentially caused by relaxed natural selection on proper chromosome pairing. In contrast, females in the sexual population showed proper homologous chromosome pairings. In individuals of both asexual and sexual populations, we find that heterochromatin was localized in centromeric regions and on the short arms of the chromosomes, GC-rich regions were associated with heterochromatic regions, and 18S rDNA genes were located on the largest chromosome pair. This comparative cytogenetic analysis contributes to our understanding about the cytological mechanisms associated with thelytokous parthenogenesis in ants and suggests the decay of chromosome structure in the absence of meiosis and genetic recombination.

Background Exponential development of minimally invasive techniques, such as robotic-assisted devices, raises the question of how to assess robotic surgery skills. Early development of virtual simulators has provided efficient tools for laparoscopic skills certification based on objective scoring, high availability, and lower cost. However, similar evaluation is lacking for robotic training. The purpose of this study was to assess several criteria, such as reliability, face, content, construct, and concurrent validity of a new virtual robotic surgery simulator. Methods This prospective study was conducted from December 2009 to April 2010 using three simulators dV-Trainers ® (MIMIC Technologies ® ) and one Da Vinci S ® (Intuitive Surgical ® ). Seventy-five subjects, divided into five groups according to their initial surgical training, were evaluated based on five representative exercises of robotic specific skills: 3D perception, clutching, visual force feedback, EndoWrist ® manipulation, and camera control. Analysis was extracted from (1) questionnaires (realism and interest), (2) automatically generated data from simulators, and (3) subjective scoring by two experts of depersonalized videos of similar exercises with robot. Results Face and content validity were generally considered high (77 %). Five levels of ability were clearly identified by the simulator (ANOVA; p  = 0.0024). There was a strong correlation between automatic data from dV-Trainer and subjective evaluation with robot ( r  = 0.822). Reliability of scoring was high ( r  = 0.851). The most relevant criteria were time and economy of motion. The most relevant exercises were Pick and Place and Ring and Rail. Conclusions The dV-Trainer ® simulator proves to be a valid tool to assess basic skills of robotic surgery.

Some species are more affected than others by edge effects resultant from habitat loss and fragmentation, generally due to human activities. As these specific responses depend on biophysical and behavioral traits of organisms, it is expected that the occurrence of species with particular traits will vary between fragment edges and interiors. Edges are also known to often harbor many invasive species. We performed a meta-analysis of the responses of insect species with different life history traits to anthropogenic edges, focusing on the species’ behavioral characteristics and whether they are considered invasive or not. We systematically searched the Web of Science database for papers on this subject published until May 2018. We examined response ratios for 712 comparisons of anthropogenic edge effects on insects. As expected, the responses differed according to the traits evaluated. Soil-foraging and social insects were negatively affected by anthropogenic edges. Conversely, flying and invasive species were favored by edges. Our analyses suggest that edges, by differently affecting different insect groups, have an important role in structuring local insect communities. Finally, the importance of functional traits in studies of edge effects must be highlighted.

Determining assembly rules of co-occurring species persists as a fundamental goal in community ecology. At local scales, the relative importance of environmental filtering vs. competitive exclusion remains a subject of debate. In this study, we assessed the relative importance of habitat filtering and competition in structuring understory ant communities in tropical forests of French Guiana. Leaf-litter ants were collected using pitfall and Winkler traps across swamp, slope and plateau forests near Saül, French Guiana. We used a combination of univariate and multivariate analyses to evaluate trait response of ants to habitat characteristics. Null model analyses were used to investigate the effects of habitat filtering and competitive interactions on community assembly at the scale of assemblages and sampling points, respectively. Swamp forests presented a much lower taxonomic and functional richness compared to slope and plateau forests. Furthermore, marked differences in taxonomic and functional composition were observed between swamp forests and slope or plateau forests. We found weak evidence for competitive exclusion based on null models. Nevertheless, the contrasting trait composition observed between habitats revealed differences in the ecological attributes of the species in the different forest habitats. Our analyses suggest that competitive interactions may not play an important role in structuring leaf-litter ant assemblages locally. Rather, habitats are responsible for driving both taxonomic and functional composition of ant communities.

Background Laparoscopic surgery is associated with a lower morbidity than open surgery. No recent data compared kidney cancer surgery in the French population using the National Health Insurance database (PMSI-MCO). Aims We explore and compare the surgical morbidity rates between laparoscopic and open laparotomy for kidney cancer. Methods The initial length of stay and complications parameters during the three postoperative months were described for renal cancer in every French center in 2018. We compared Relative Risks (RR [95% CI]) between laparoscopic and open surgery for both radical and partial nephrectomy. Results Among 8,162 patients, 3,525 had a radical nephrectomy, 978 open, 2,547 laparoscopic surgeries; 4,637 patients had partial nephrectomies, 1,778 open 2,859 laparoscopic surgeries. For radical surgery, the most common complications were urinary infections (7.8%), acute renal failure (8.9%), sepsis (8.4%), bleeding (9.3%), and postoperative anemia (5.9%); the RR for laparoscopic versus open surgery were respectively 0.68 [0.54;0.86], 0.71 [0.57;0.88], 0.69 [0.55;0.86], 0.83 [0.66;1.03], 0.56 [0.43;0.73]. For partial nephrectomies, the most common complications were urinary infections (7.7%), bleeding (11.6%), and postoperative anemia (5.8%), with RR of 0.71 [0.58;0.87], 0.61 [0.52;0.71], and 0.64 [0.51;0.81]. The mean length of stay was 7.7 for open radical nephrectomy, 6.3 for laparoscopic radical nephrectomy, 7.5 for open partial nephrectomy, and 5 for laparoscopic partial nephrectomy. Conclusions The laparoscopic approach had fewer postoperative complications and a shorter length of stay than open surgery for partial and radical nephrectomy. The PMSI analysis provided an exhaustive description of surgical practice for kidney cancer and surgical complications in France. Clinical trial number Not applicable.

Purpose To evaluate three partial nephrectomies (PN) procedures: open (OPN), standard laparoscopy (LPN), and robot-assisted laparoscopy (RAPN), for the risk of initial complications and rehospitalization for two years after the surgery. Materials and methods From the French national hospital database (PMSI-MCO), every hospitalization in French hospitals for renal tumor PN in 2016–2017 were extracted. Complications were documented from the initial hospitalization and any rehospitalization over two years. Chi-square and ANOVA tests compared the frequency of complications and length of initial hospitalization between the three surgical procedures. Relative risks (RR) and 95% confidence intervals were computed. Results The 9119 initial hospitalizations included 4035 OPN, 1709 LPN, and 1900 RAPN; 1475 were excluded as the laparoscopic procedure performed was not determined. The average length of hospitalization was 8.1, 6.2, and 4.5 days for OPN, LPN, and RAPN, respectively. Compared to OPN, there were fewer complications at the time of initial hospitalization for the mini-invasive procedures: 29% for OPN vs. 20% for LPN (0.70 [0.63;0.78]) and 12% for RAPN (RR=0.43, 95%CI [0.38;0.49]). For RAPN compared to LPN, there were fewer haemorrhages (RR=0.55 [0.43;0.72]), anemia (0.69 {0.48;0.98]), and sepsis (0.51 [0.36;0.71]); during follow up, there were fewer urinary tract infections (0.64 [0.45;0.91]) but more infectious lung diseases (1.69 [1.03;2.76]). Over the two-year postoperative period, RAPN was associated with fewer acute renal failures (RR=0.73 [0.55;0.98]), renal abscesses (0.41 [0.23;0.74]), parietal complications (0.69 [0.52;0.92]) and urinary tract infections (0.54 [0.40;0.73]) than for OPN. Conclusions Conservative renal surgery is associated with postoperative morbidity related to the surgical procedure fashion. Mini-invasive procedures, especially robot-assisted surgery, had fewer complications and shorter hospital lengths of stay

Arboreal ants occupy a thermally dynamic environment, yet the mechanisms integrating nest architecture and worker behavior to maintain colony homeostasis remain understudied. We investigated the interplay among circadian rhythm, nest homeostasis, and worker morphology in Azteca chartifex spiriti, a Neotropical arboreal species that builds large polydomous nests suspended in trees. In ten colonies, we measured internal moisture and temperature gradients in the main nest, which houses most individuals, including the reproductive female, immatures, and numerous workers. In six colonies, we assessed the polymorphism of foraging workers over a 24 h cycle in relation to external temperature variation. The results show integrated thermoregulatory mechanisms that combine passive strategies, derived from nest architecture and moisture gradients from the suspension base to the lower extremity, with active strategies linked to foraging patterns and worker polymorphism. Internal temperature (27.8 ± 2.41 °C) remained buffered relative to external fluctuations, and moisture was significantly higher at the nest’s lower extremity (p < 0.001). Worker size displayed a bimodal distribution during the day that shifted to a unimodal pattern at night, indicating behavioral adjustments to thermal and operational demands. These findings demonstrate that the interaction between physical structure and worker behavior maintains colony homeostasis, providing essential insights into how dominant canopy ants may cope with future climate change scenarios.

Two valid ant species, Camponotus rufipes and Camponotus renggeri, have recently been the subject of a broad discussion with reference to taxa synonymization. Both species are quite common among the Neotropical myrmecofauna and share some unique traits, such as the shape of the scape and the pilosity patterns of the tibiae and scapes. A single morphological trait can help distinguish these species; however, only a combination of different approaches can enlighten our view of the complex phylogenetic relationships prevailing in the different populations of these two taxa. Therefore, focusing on the taxonomic issues concerning these two species, a cytogenetic survey including 10 populations of C. rufipes and two populations of C. renggeri was performed. In order to better understand the extent of the relationship between C. rufipes and C. renggeri, two common Neotropical Camponotus species, C. atriceps and C. cingulatus were taken as outgroups. All four species of Camponotus that were studied had 2n = 40 chromosomes (4sm+34st+2t); however, the abundance of chromosome rearrangements observed, combined with several chromosome markers, suggest that C. rufipes and C. renggeri are two good distinct species although closely related. The already reported chromosome translocation 2n = 39 (1m+4sm+32st +2t) for C. rufipes has been found in different populations as in the unprecedented chromosome inversions found both in C. rufipes and in C. renggeri populations. Within the C. renggeri chromosome inversions, both the heterozygous state 2n = 40 (1m+3sm+34st+2t) and the homozygous state, 2n = 40 (2m+2sm+34st+2t) were identified. However, only het- erozygous specimens for chromosome inversions were found among C. rufipes, with karyotype configurations distinct from those found in C. renggeri, with 2n = 40 (1m+4sm+34st +2t). None of the populations studied showed signs of mosaic individuals. With respect to rDNA clusters, the 18S rDNA seemed to be more restricted inside the genome, as C. renggeri showed four 18S rDNA clusters, whereas, C. rufipes, C. atriceps, and C. cingulatus showed only two clusters. The chromosome locations of the 5S rDNA clusters were pointed for the first time in Formicidae, and showed itself to be more widely spread over the genome. By combining different chromosome banding approaches it was possible to demonstrate the crucial importance that chromosome inversions played on the karyotype evolution within these ants. The results also showed that chromosome translocations might be a consequence of the chromatin dynamic condition observed among Camponotus species. The homozygosis condition found in a C. renggeri from a Brazilian savanna population for chromosome inversions and the contrasting heterozygous condition for a different kind of chromosome inversion in C. rufipes from the Brazilian coastal rainforest, opens the window for a chromosome race hypothesis within the group C. renggeri and C. rufipes. The wide distribution, rich ecological interactions, genetic diversity, and morphological variability among C. renggeri and C. rufipes justify questioning of the actual taxonomic status of these species. The answer of this puzzle is clear when observing the number of 18S rDNA clusters of these ants, as C. rufipes has only two clusters whereas C. renggeri has four.