Scope actuation system for articulated laparoscopes

Background: An articulated laparoscope comprises a rigid shaft with an articulated distal end to change the viewing direction. The articulation provides improved navigation of the operating field in confined spaces. Furthermore, incorporation of an actuation system tends to enhance the control of an articulated laparoscope. Methods: A preliminary prototype of a scope actuation system to maneuver an off-the-shelf articulated laparoscope (EndoCAMaleon by Karl Storz, Germany) was developed. A user study was conducted to evaluate this prototype for the surgical paradigm of video-assisted thoracic surgery. In the study, the subjects maneuvered an articulated scope under two modes of operation: (a) actuated mode where an operating surgeon maneuvers the scope using the developed prototype and (b) manual mode where a surgical assistant directly maneuvers the scope. The actuated mode was further assessed for multiple configurations based on the orientation of the articulated scope at the incision. Results: The data show the actuated mode scored better than the manual mode on all the measured performance parameters including (a) total duration to visualize a marked region, (a) duration for which scope focus shifts outside a predefined visualization region, and (c) number of times for which scope focus shifts outside a predefined visualization region. Among the different configurations tested using the actuated mode, no significant difference was observed. Conclusions: The proposed articulated scope actuation system facilitates better navigation of an operative field as compared to a human assistant. Secondly, irrespective of the orientation in which an articulated scope’s shaft is inserted through an incision, the proposed actuation system can navigate and visualize the operative field

A generic scope actuation system for flexible endoscopes

Background: A scope actuation system assists a surgeon in steering a scope for navigating an operative field during an interventional or diagnostic procedure. Each system is tailored for a specific surgical procedure. The development of a generic scope actuation system could assist various laparoscopic and endoscopic procedures. This has the potential to reduce the deployment and maintenance costs for a hospital, making it more accessible for clinical usage. Methods: A modular actuation system (for maneuvering rigid laparoscopes) was adapted to enable incorporation of flexible endoscopes. The design simplifies the installation and disassembly processes. User studies were conducted to assess the ability of the system to focus onto a diagnostic area, and to navigate during a simulated esophagogastroduodenoscopy procedure. During the studies, the endoscope was maneuvered with (robotic mode) and without (manual mode) the actuation system to navigate the endoscope’s focus on a predefined track. Results: Results show that the robotic mode performed better than the manual mode on all the measured performance parameters including (a) the total duration to traverse a track, (b) the percentage of time spent outside a track while traversing, and (c) the number of times the scope focus shifts outside the track. Additionally, robotic mode also reduced the perceived workload based on the NASA-TLX scale. Conclusions: The proposed scope actuation system enhances the maneuverability of flexible endoscopes. It also lays the groundwork for future development of modular and generic scope assistant systems that can be used in both laparoscopic and endoscopic procedures

Depleted and Collapsed Marine Fish Stocks along Southwest Coast of India – A Simple Criterion to Assess the Status

India’s marine fishery has grown from a subsistence level to an industrial one. From a meagre 0.6 million tonnes in 1950s it has crossed 3.0 million tonnes in 2008. Kerala, and to a lesser extent, Karnataka have been the major contributors to the marine fish production of the country (having 12% of the total coastline and contributing 30-35% of the production). Mechanization of the fishing fleets has focussed increased effort on the fish stocks in the region (southwest coast), and consequently, many stocks are not as abundant as they were before. The intense exploitation of commercial marine species along these coasts has reportedly led to threats of species loss. So far no comprehensive study has been made to assess the health of Indian marine fish stocks with respect to depletion and collapse, and therefore, no restoration or stock rebuilding plans are available. Most of the world’s most valuable fish stocks are either fully exploited or overexploited (FAO, 2007). The 25% of the stocks that remain underexploited tend to comprise of low-value species

भारत के दक्षिण-पशिचम तट में 1926-2005 के दौरान तारली और बँगडा मात्स्यिकी में हुए उतार-चढाव पर पर्यावरणीय प्राचलों क प्रभाव

कृपया पूरा लेखा पढ

How environmental parameters influenced fluctuations in oil sardine and mackerel fishery during 1926-2005 along the south-west coast of India?

The south-west coast of India is one of the major upwelling systems of the world (Malabar upwelling zone) and contributes to nearly 30-50% of the total marine fish catch from India. Generally, the coastal upwelling ecosystems are colonized by planktivorous small pelagic fishes such as anchovies, sardines and these fish populations are characterized by significant inter-annual fluctuations in their abundance

Alpha, beta and gamma diversity of fished marine taxa along the southwest coast of India during 1970-2005

The data on species-wise marine fish landings at Kerala and Karnataka during 1970-2005 were used to examine diversities of fished taxa through alpha, beta, and gamma diversities which are the fundamental descriptive variables of ecology and conservation biology. In Kerala, fishing zone K5 (Kochi) and K3 (Kollam-Neendakara) and in Karnataka, fishing zone KN4 (Gangolli-Coondapur - northern Udupi district) followed by KN11 (Mangalore) had high alpha diversity values. These zones are major trawling zones. The beta diversity values and the species turnover rates were also high for these zones. The high beta values indicate uniqueness in species diversity when compared to other zones. The gamma diversity was 818 for Kerala and 524 for Karnataka. Beta diversity index showed a positive relationship with alpha index, indicating dependence of beta on alpha values. While the arthropod diversity was similar in Kerala and Karnataka, the chordate and mollusc diversity was higher in Kerala. The results from the present study indicate that similar studies have to be carried out from other ecosystems along the Indian coast, so that it becomes benchmark information for studying the anthropogenic impacts on biodiversity

Use of Size-based Indicators for evaluating long-term trends in Indian oil sardine (Sardinella longiceps) fishery

Size-based indicators (SBIs) are being currently used to evaluate the response of fish populations to exploitation, and may also lead to the development of an ecosystem based fisheries management (EBFM) approach. At a population level, the selective removal of larger or smaller fish will be reflected in changes in mean length (L mean) or mean weight (W mean), maximum length (L max) and minimum length (L min) of the population

Phylogeny and evolution of life-history strategies in the Sycophaginae non-pollinating fig wasps (Hymenoptera, Chalcidoidea)

<p>Abstract</p> <p>Background</p> <p>Non-pollinating Sycophaginae (Hymenoptera, Chalcidoidea) form small communities within <it>Urostigma </it>and <it>Sycomorus </it>fig trees. The species show differences in galling habits and exhibit apterous, winged or dimorphic males. The large gall inducers oviposit early in syconium development and lay few eggs; the small gall inducers lay more eggs soon after pollination; the ostiolar gall-inducers enter the syconium to oviposit and the cleptoparasites oviposit in galls induced by other fig wasps. The systematics of the group remains unclear and only one phylogeny based on limited sampling has been published to date. Here we present an expanded phylogeny for sycophagine fig wasps including about 1.5 times the number of described species. We sequenced mitochondrial and nuclear markers (4.2 kb) on 73 species and 145 individuals and conducted maximum likelihood and Bayesian phylogenetic analyses. We then used this phylogeny to reconstruct the evolution of Sycophaginae life-history strategies and test if the presence of winged males and small brood size may be correlated.</p> <p>Results</p> <p>The resulting trees are well resolved and strongly supported. With the exception of <it>Apocrytophagus</it>, which is paraphyletic with respect to <it>Sycophaga</it>, all genera are monophyletic. The Sycophaginae are divided into three clades: (i) <it>Eukoebelea</it>; (ii) <it>Pseudidarnes</it>, <it>Anidarnes </it>and <it>Conidarnes </it>and (iii) <it>Apocryptophagus</it>, <it>Sycophaga </it>and <it>Idarnes</it>. The ancestral states for galling habits and male morphology remain ambiguous and our reconstructions show that the two traits are evolutionary labile.</p> <p>Conclusions</p> <p>The three main clades could be considered as tribes and we list some morphological characters that define them. The same biologies re-evolved several times independently, which make Sycophaginae an interesting model to test predictions on what factors will canalize the evolution of a particular biology. The ostiolar gall-inducers are the only monophyletic group. In 15 Myr, they evolved several morphological adaptations to enter the syconia that make them strongly divergent from their sister taxa. Sycophaginae appears to be another example where sexual selection on male mating opportunities favored winged males in species with small broods and wingless males in species with large broods. However, some species are exceptional in that they lay few eggs but exhibit apterous males, which we hypothesize could be due to other selective pressures selecting against the re-appearance of winged morphs.</p