| 1. |
- Falahzadeh, A., et al.
(författare)
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A New Coastal Crawler Prototype to Expand the Ecological Monitoring Radius of OBSEA Cabled Observatory
- 2023
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Ingår i: Journal of Marine Science and Engineering. ; 11:4
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Tidskriftsartikel (refereegranskat)abstract
- The use of marine cabled video observatories with multiparametric environmental data collection capability is becoming relevant for ecological monitoring strategies. Their ecosystem surveying can be enforced in real time, remotely, and continuously, over consecutive days, seasons, and even years. Unfortunately, as most observatories perform such monitoring with fixed cameras, the ecological value of their data is limited to a narrow field of view, possibly not representative of the local habitat heterogeneity. Docked mobile robotic platforms could be used to extend data collection to larger, and hence more ecologically representative areas. Among the various state-of-the-art underwater robotic platforms available, benthic crawlers are excellent candidates to perform ecological monitoring tasks in combination with cabled observatories. Although they are normally used in the deep sea, their high positioning stability, low acoustic signature, and low energetic consumption, especially during stationary phases, make them suitable for coastal operations. In this paper, we present the integration of a benthic crawler into a coastal cabled observatory (OBSEA) to extend its monitoring radius and collect more ecologically representative data. The extension of the monitoring radius was obtained by remotely operating the crawler to enforce back-and-forth drives along specific transects while recording videos with the onboard cameras. The ecological relevance of the monitoring-radius extension was demonstrated by performing a visual census of the species observed with the crawler's cameras in comparison to the observatory's fixed cameras, revealing non-negligible differences. Additionally, the videos recorded from the crawler's cameras during the transects were used to demonstrate an automated photo-mosaic of the seabed for the first time on this class of vehicles. In the present work, the crawler travelled in an area of 40 m away from the OBSEA, producing an extension of the monitoring field of view (FOV), and covering an area approximately 230 times larger than OBSEA's camera. The analysis of the videos obtained from the crawler's and the observatory's cameras revealed differences in the species observed. Future implementation scenarios are also discussed in relation to mission autonomy to perform imaging across spatial heterogeneity gradients around the OBSEA.
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| 2. |
- Schultheis, M., et al.
(författare)
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The nuclear stellar disc of the Milky Way : A dynamically cool and metal-rich component possibly formed from the central molecular zone
- 2021
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Ingår i: Astronomy and Astrophysics. - : EDP Sciences. - 0004-6361 .- 1432-0746. ; 650
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Tidskriftsartikel (refereegranskat)abstract
- Context. The nuclear stellar disc (NSD) is, together with the nuclear star cluster (NSC) and the central massive black hole, one of the main components in the central parts of our Milky Way. However, until recently, only a few studies of the stellar content of the NSD have been obtained owing to extreme extinction and stellar crowding. Aims. We study the kinematics and global metallicities of the NSD based on the observations of K/M giant stars via a dedicated KMOS (VLT, ESO) spectroscopic survey. Methods. We traced radial velocities and metallicities, which were derived based on spectral indices (Na I and CO) along the NSD, and compared those with a Galactic bulge sample of APOGEE (DR16) and data from the NSC. Results. We find that the metallicity distribution function and the fraction of metal-rich and metal-poor stars in the NSD are different from the corresponding distributions and ratios of the NSC and the Galactic bulge. By tracing the velocity dispersion as a function of metallicity, we clearly see that the NSD is kinematically cool and that the velocity dispersion decreases with increasing metallicity contrary to the inner bulge sample of APOGEE (|b|< 4°). Using molecular gas tracers (H2CO, CO(4-3)) of the central molecular zone (CMZ), we find an astonishing agreement between the gas rotation and the rotation of the metal-rich population. This agreement indicates that the metal-rich stars could have formed from gas in the CMZ. On the other hand, the metal-poor stars show a much slower rotation profile with signs of counter-rotation, thereby indicating that these stars have a different origin. Conclusions. Coupling kinematics with global metallicities, our results demonstrate that the NSD is chemically and kinematically distinct with respect to the inner bulge, which indicates a different formation scenario.
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| 3. |
- da Silva, G. M., et al.
(författare)
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The effect of diverticular disease on the colonic J pouch
- 2004
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Ingår i: Colorectal disease. - 1462-8910. ; 6:3, s. 171-5
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVE: The aim of this study was to assess the impact of the diverticular disease (DD) on function and on postoperative complications of the colonic J-pouch (CJP) with pouch-anal anastomosis. METHODS: Patients who underwent a CJP between December 1990 and August 2001, were retrospectively reviewed. The presence of DD in the CJP was assessed on pouchogram prior to ileostomy closure. A questionnaire designed to evaluate the degree of continence (total incontinence score (IS): 0 = worst, 20 = best) and pouch evacuation (total evacuation score (ES): 0 = worst, 28 = best) was used for comparison between patients with DD and those without DD (NDD). RESULTS: Sixty-six patients (47 males; 19 females) with a median age of 68 years (range 28-87 years) were included. The median follow-up period was 22 months (range 2-106 months). Twenty-four patients comprised the DD group and 42 were in the NDD group. The two groups were comparable for age, gender and time from ileostomy closure; all patients with postoperative chemoradiation therapy were in the NDD group. The total ES and IS total did not significantly differ between the two groups with a P-value of 0.11 and 0.09 respectively. Furthermore, there was no significant difference in the total incidence of pouch complications between the two groups (3 strictures, 1 leak, 1 fistula in the NDD group vs. 1 pelvic sepsis in the DD group; P = 0.4). CONCLUSIONS: The presence of DD in a CJP does not seem to impact pouch function or the postoperative complication rate.
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| 4. |
- da Silva, Giovanna M, et al.
(författare)
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The efficacy of a nerve stimulator (CaverMap) to enhance autonomic nerve identification and confirm nerve preservation during total mesorectal excision.
- 2004
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Ingår i: Diseases of the colon and rectum. - : Ovid Technologies (Wolters Kluwer Health). - 0012-3706. ; 47:12, s. 2032-8
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Tidskriftsartikel (refereegranskat)abstract
- PURPOSE: Sexual dysfunction after total mesorectal excision may be caused by injury to the autonomic nerves. During surgery, nerve identification is not always achieved, and, to date, there has been no method to objectively confirm nerve preservation. The aim of this study was to assess the efficacy of a nerve-stimulating device (CaverMap) to assist in the intraoperative identification of the autonomic nerves during total mesorectal excision, and objectively confirm nerve preservation after proctectomy is completed. PATIENTS AND METHODS: Sexually active consecutive male patients undergoing total mesorectal excision were prospectively enrolled in this study. During pelvic dissection, the surgeon attempted to localize the hypogastric and cavernous nerves. CaverMap was used to confirm these findings and to facilitate the identification in cases of uncertainty. At the completion of proctectomy, the nerves were restimulated to ensure preservation. Factors that could affect the surgeon's ability to localize the nerves and CaverMap to confirm this were evaluated. RESULTS: Twenty-nine male patients with a median age of 58 years were enrolled in this study. An attempt to visualize the hypogastric nerves during dissection was made in 26 patients; the surgeon was able to identify the nerves in 19 (73 percent) patients. CaverMap successfully identified the nerves in six of the seven remaining patients, and failed to identify them in only one case. An attempt to localize the cavernous nerves during dissection was made in 13 patients, of which localization was successful in 8 (61.5 percent) patients. CaverMap improved the identification rate in four of the remaining five patients. After proctectomy, CaverMap successfully confirmed the preservation of both hypogastric and cavernous nerves in 27 of 29 (93 percent) patients. A history of previous surgery statistically correlated with failure to identify the hypogastric nerves by the surgeon (P = 0.005). There were no adverse events related to use of the device. CONCLUSION: CaverMap may be a useful tool to facilitate identification of the pelvic autonomic nerves during total mesorectal excision and to objectively confirm nerve preservation.
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| 5. |
- Ho, Kok Sun, et al.
(författare)
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Ileal pouch anal anastomosis for ulcerative colitis is feasible for septuagenarians.
- 2006
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Ingår i: Colorectal disease : the official journal of the Association of Coloproctology of Great Britain and Ireland. - : Wiley. - 1462-8910. ; 8:3, s. 235-8
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVE: Proctocolectomy and ileal pouch anal anastomosis (IPAA) has become the standard surgery for patients with mucosal ulcerative colitis (MUC). Although there is no absolute age limitation, there are concerns as to its use in elderly patients due to the risks of potential complications and poor function. The aim of this study was to assess the complications and outcome of patients over the age of 70 years with MUC who underwent IPAA. Results in these patients were compared to the results in a group of patients aged less than 70 years who had IPAA. METHODS: After Institutional Review Board approval, a retrospective review of the medical records of patients with MUC who underwent IPAA was undertaken. These patients were divided into four age groups: <30 years of age, 30-49 years, 50-69 years, >or=70 years. RESULTS: From 1989 to 2001, 330 patients underwent IPAA for preoperative clinical and histopathological and postoperative histopathologically confirmed MUC; 17 were aged>or=70 years. The mean hospital stay was 5.8 (SEM 0.7) days in the patients aged<70 years and 6.0 (SEM 0.4) days in the patients aged>or=70 years (P=0.911). Postoperative complications occurred in 39% of patients>or=70 years and in 40% in the <70 years group (P=0.08). Pouch failure occurred in two (11.8%) patients>or=70 years and in 6 (1.9%)<70 (P=0.2). CONCLUSION: IPAA is a safe and feasible option in MUC patients over the age of 70 with functional results similar to results seen in younger patients.
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| 6. |
- Petkova, Maya, 1990, et al.
(författare)
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Kinematics of Galactic Centre clouds shaped by shear-seeded solenoidal turbulence
- 2023
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Ingår i: Monthly Notices of the Royal Astronomical Society. - 0035-8711 .- 1365-2966. ; 525:1, s. 962-968
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Tidskriftsartikel (refereegranskat)abstract
- The Central Molecular Zone (CMZ; the central ∼500 pc of the Galaxy) is a kinematically unusual environment relative to the Galactic disc, with high-velocity dispersions and a steep size-linewidth relation of the molecular clouds. In addition, the CMZ region has a significantly lower star formation rate (SFR) than expected by its large amount of dense gas. An important factor in explaining the low SFR is the turbulent state of the star-forming gas, which seems to be dominated by rotational modes. However, the turbulence driving mechanism remains unclear. In this work, we investigate how the Galactic gravitational potential affects the turbulence in CMZ clouds. We focus on the CMZ cloud G0.253+0.016 ('the Brick'), which is very quiescent and unlikely to be kinematically dominated by stellar feedback. We demonstrate that several kinematic properties of the Brick arise naturally in a cloud-scale hydrodynamics simulation, that takes into account the Galactic gravitational potential. These properties include the line-of-sight velocity distribution, the steepened size-linewidth relation, and the predominantly solenoidal nature of the turbulence. Within the simulation, these properties result from the Galactic shear in combination with the cloud's gravitational collapse. This is a strong indication that the Galactic gravitational potential plays a crucial role in shaping the CMZ gas kinematics, and is a major contributor to suppressing the SFR, by inducing predominantly solenoidal turbulent modes.
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