Konstantinos Kyriakopoulos

Phreatomagmatic ash from the ongoing eruption of Etna reaching the Greek island of Cefalonia

On October 26, 2002, Etna volcano, Sicily (southern Italy), entered a new eruptive phase, characterised by the usual effusive activity from fissure vents located both on the southern and on the northern sector of the summit area. In addition, explosive events of unusual intensity were recorded at the beginning of the eruption and produced a substantial plume rich in fine ash particles and steam. On October 27, fine ash from the plume, blown by the wind, was reported falling on the island of Cefalonia, Greece, which is located approximately 500 km east of the volcano. In this communication, we report on the study of fine ash from the eruption as collected on Cefalonia. We elaborate on the nature of the peculiar type of explosion mechanism that led to such an unusual manifestation of Etna, which is phreatomagmatism. This finding draws a new picture of the eruptive scenario of this active volcano, and requires a careful evaluation of the hazard that similar events might pose in the future. Not just the surroundings of the volcano but also the aviation corridors of the southern Mediterranean area could be potentially affected.

Simultaneous localization and map building of skid-steered robots

In this article, an alternative scheme is proposed for the SLAM problem, where the state vector holds only the robot pose and the map is feature-based in the form of line segments. It is a lighter representation in comparison to occupancy grids and point maps, something necessary as large scale environments are addressed. The basic idea is to obtain one estimate of the robots pose from an innovative dead-reckoning scheme and one from a laser scan matching algorithm. The fusion is done through a covariance intersection filter, avoiding the assumption that holds in Kalman filter that the cross correlations are zero. In this way, the uncertainty of pose estimate while the cross correlations are unknown and non zero are minimized. In the following section, the general framework of the SLAM algorithm is described. Then a short description of the dead-reckoning scheme, feature extraction scheme and the map matching algorithm are discussed. The loop with the covariance intersection fusion of the robot pose estimates are concluded. The description of the global map update algorithm and the results from representative experiments in real world experimental conditions are presented

The impact on water quality of the high carbon dioxide contents of the groundwater in the area of Florina (N. Greece)

Gas and water samples were collected at CO2-rich wells in the plain of Florina (N. Greece). Chemical and isotopic composition of the analysed gases reveals their main crustal origin even if a small but significant contribution of mantle derived gases can be recognized. As a consequence of CO2 dissolution, HCO3 - is always the main dissolved anion while cationic composition allows us to distinguish at least two main groups characterized by Na or Ca as dominant dissolved cations. The water-rock interaction is strongly enhanced by the dissolution of CO2 and the consequent lowering of pH. Such a process increases the mobility of some trace elements whose concentrations very often exceed UE drinking water limits. This study confirms that the Florina basin represents a good natural analogue of carbon storage systems and underscores the fact that possible deterioration of water quality due to CO2 leaks of the reservoirs must be carefully taken in account.

Recurrent benign leiomyomas after total abdominal hysterectomy. Rich or poor estrogenic environment may lead to their recurrence

Highlights • BML is a rare entity that usually affects women after hysterectomy for leiomyomas.• This is one of few reports in literature of tumors’ appearance in the same patient both in estrogen rich and poor environment.• Τransvaginal ultrasonography seems to be a pivotal tool for the diagnosis and follow up of these challenging lesions.

OP29.10: Inversion image analysis: it could be the future in the preoperative diagnosis of ovarian lesions

according to the IOTA protocol. A proper counselling on a low ovarian cancer risk was given and an adequate informed consent was obtained. Sonographic follow-up was proposed at 3 and 9 months, than yearly. Surgery was proposed in case of changes of ovarian cyst volume (> 50%) and/or sonographic parameters at TVS-CD. Demographic, medical, sonographic and pathologic data were recorded. Results: 98 post-menopausal patients with 106 ovarian cysts were enrolled. Median age (IR) was 69 years (59–74). Median years after menopause (IR) were 18 (8–24). Median BMI (IR) was 26 kg/m2 (24–29). Mean parity (±sd) was 2 ± 1.8 women reported bilateral cysts. 53 cysts were unilocular, 53 multilocular. Median cyst diameter (IR) of unilocular and multilocular ovarian cysts was 50 mm (34–56). At a median follow-up period of 36 months, surgery was performed in 28 cases: 14 patients required immediate removal, 5 drop-out, 9 volume changes. One successfully managed cardiac arrest occurred during laparoscopic procedure. No malignant lesions were reported at histology. Conclusions: Sonographic follow-up might be a useful option in the clinical management of incidental unilocular > 5 cm and multilocular < 7 cm ovarian cysts in post-menopausal women. Larger and longer multicentres studies with strict sonographic parameters are needed to support this potentially safe conservative management.

P11.09: Diagnostic accuracy of enhanced ultrasonography in subfertile women

A 24 year old patient presenting with primary amenorrhea and primary infertility of 6 years was diagnosed as MayerRokitansky-Küster-Hauser (MRKH) syndrome. She was confirmed to have a normal karyotype (46, XX) and normal sexual development. Serial hormonal determinations indicated normal ovarian function and appropriate early follicular FSH; LH levels(4.58IU/L;5.2IU/L). On evaluation of pelvis a solitary kidney was visualised with ultrasonography and MRI. Bilateral ovaries were located close to abdominal wall laterally. Her ovaries could not be adequately imaged transvaginally with a 5-MHz to 9-MHz transvaginal ultrasound probe. The ovaries located entirely lateral to bilateral pelvic brims were better visualized using a 2-MHz to 7-MHz transabdominal probe. Following controlled ovarian hyperstimulation and 36 hours after hCG trigger, eight M2 oocytes were retrieved transabdominal-transperitoneally with transvaginal ultrasound probe guidance (Figure 1). Four grade 1 embryos were vitrified. Transabdominal-transperitoneal ultrasound guided oocyte retrieval might be more adequate in selected cases.

OP24.01: 3D procedure: immediate response for benignity or malignancy of ovarian lesions

equipped with an X7 matrix array transducer (2–7 MHz) and a custom designed RF interface (sampling frequency 32 MHz) in biplane mode. The displacement of the fetal aortic wall can be estimated accurately by finding the maximum of the cross correlation function of two consecutive wall reflections. Based on the sampling frequency, the resolution of wall displacement in the direction of the ultrasound beam is 24 micrometers and is improved to a few micrometers by applying quadratic interpolation. By overlaying RF data relative to the tracked aortic wall a detailed mean wall reflection can be derived. Data analysis showed that the aortic wall reflection can be described by the sum of two Gaussian pulses with center frequency and the fractional bandwidth equal to those of the emit ultrasound pulse. An iterative algorithm that minimizes the sum of squared differences between the model-based and measured mean wall reflection was employed to fit the parameters of the model. Results: The mean IMT (N = 83, GA 22 to 38 wks) for the near and far wall in the longitudinal and cross sectional plane were 0.34 (+0.17), 0.34 (+0.17), 0.43 (+0.26) and 0.38 (+0.20) respectively and neither related with gestational age nor was statistically different from each other (Friedman test, P = 0.201). Conclusions: Fetal aortic intima media thickness, 0.4 mm as measured in this study is only a fraction of those reported in other published data, 1.90 mm and 1.15 mm in fetuses and newborns respectively as derived from caliper settings in B-mode images. The results presented here might indicate overestimation of B-mode derived fetal aortic IMT measurements in prior studies.