396 research outputs found
Optimal pareto solutions of a dynamic C chart: An application of statistical process control on a semiconductor devices manufacturing process
The present paper proposes a novel economic-statistical design procedure of a dynamic c control chart for the Statistical Process Control (SPC) of the manufacturing process of semiconductor devices. Particularly, a non-linear constrained mathematical programming model is formulated and solved by means of the \u3b5-constraint method. A numerical application is developed in order to describe the Pareto frontier, that is the set of optimal c charts and the related practical considerations are given. The obtained results highlight how the performance of the developed dynamic c chart overcome that of the related static one, thus demonstrating the effectiveness of the proposed procedure
An improved seismicity picture of the Southern Tyrrhenian area by the use of OBS and land-based networks: the TYDE experiment
The problem of large location uncertainties for seismicity occurring in the Southern Tyrrhenian
Sea have been partially exceeded during the implementation of the long-term scientific mission of
the TYrrhenian Deep sea Experiment (TYDE), which allowed the installation of 14 wide-band
Ocean Bottom Seismometers (OBS) and Hydrophones (OBH) in the period December 2000 – May
2001 on the sea-bottom floor around the Aeolian and Ustica Islands. Local events recorded at landstations
have been observed also on the seismograms of the Ocean Bottom Seismic Network
(OBSN). Moreover, some hundreds of low magnitude events, undetected from the land networks,
have been recorded.
We combined the readings of body wave arrival times from OBS-OBH with those from landstations
to localise seismic events. We focused our study on three clusters of events representative
of the seismic activity of the area: (i) “deep” events, (ii) Ustica (iii) NE-Sicily. The analysis of the
integrated data set of the seismicity off-shore and on-shore, obtained from the combined land-OBS
seismic network (Ustica sequence and Deep events), has improved locations in terms of RMS
residuals, azimuthal gap, epicentral and hypocentral errors. Moreover, further classes of events have
been analysed: the first one includes some local events that could be located only by integrating single trigger readings from the few available land-stations with the OBSN-data; the second one
comprises local events that have been detected only by the OBS-OBH stations. In particular, the last
cluster underlines the importance of an OBSN in the Tyrrhenian deep basin to reveal its unknown
intense micro-seismicity, permitting to better understand both the tectonic and geodynamic picture
of the area
Relationship between tremor and volcanic activity during the Southeast Crater eruption on Mount Etna in early 2000
The Southeast Crater of Mount Etna (Italy) was characterized by a violent eruptive
activity between 26 January and 24 June 2000. This activity produced 64 lava fountain
episodes with repose periods from 3 hours to 10 days. We estimated a volume of about
15–20 106 m3 lava and at least 2–3 106 m3 of tephra. We compared the
paroxysmal volcanic activity to its associated seismic signature: The high number of
events highlighted a strict correlation between tremor and volcanic activity. Seismic and
volcanic characteristics, such as the frequency of occurrence, the duration of lava
fountains and the associated tremor energy, suggested the subdivision of the studied
period into two stages separated by the 20 February event. Combining volcanic with
seismic data, we observed some useful relationships among lava fountain height,
sustained column height and Reduced Displacement; in addition, we found that the entire
episode was well correlated with the duration of the amplitude increase. Computing the
tremor energy linked to each event, the total energy associated with lava fountains
episodes results in 76% of the energy released during the whole period. Finally, the
different ratios among the overall spectral amplitude of the seismic signals of the stations
located at different altitudes suggested to us the elaboration of a simple qualitative model
to explain the dynamic behavior of the tremor source during the whole episode
Historical analysis of national subjective wellbeing using millions of digitized books
In addition to improving quality of life, higher subjective wellbeing leads to fewer health problems and higher productivity, making subjective wellbeing a focal issue among researchers and governments. However, it is difficult to estimate how happy people were during previous centuries. Here we show that a method based on the quantitative analysis of natural language published over the past 200 years captures reliable patterns in historical subjective wellbeing. Using sentiment analysis on the basis of psychological valence norms, we compute a national valence index for the United Kingdom, the United States, Germany and Italy, indicating relative happiness in response to national and international wars and in comparison to historical trends in longevity and gross domestic product. We validate our method using Eurobarometer survey data from the 1970s and demonstrate robustness using words with stable historical meanings, diverse corpora (newspapers, magazines and books) and additional word norms. By providing a window on quantitative historical psychology, this approach could inform policy and economic history
Seismic location improvements from an OBS/H temporary network in Southern Tyrrhenian Sea
We present the first investigation performed on the seismicity of Southern Tyrrhenian Sea, off-shore Sicily
with the contribution of data from broad-band ocean bottom seismometers and hydrophones (OBS/H). Offshore
data were recorded during the TYrrhenian Deep sea Experiment (TYDE) from December 2000 to May
2001 in the Southern Tyrrhenian Sea. Hypocenter locations of a cluster of 53 seismic events occurred in
March 2001 in north-eastern Sicily were estimated by the integration of land (permanent network) and offshore
(temporary network) data and compared with locations estimated from land data only. The scatter of
the cluster was evaluated by dispersion parameters. The off-shore data significantly reduced the scatter of
the swarm hypocenters also restricting the depth range of the cluster. Moreover, space trends of the event
distribution originally shown by the land data were only partially confirmed by the land-sea joint data.
In order to assess the efficiency in terms of hypocenter mislocations in the subject area, of a land-sea
integrated network with respect to a land-based network, we performed simulations by assuming a grid
distribution of earthquakes and a recent local 3D velocity model, computing synthetic arrival times of body
waves to the stations of both network configurations (integrated and land-based) perturbing the computed
times and relocating earthquakes by inversion. The results of the synthetic tests demonstrated that the
presence of sea bottom stations in the Tyrrhenian basin can reduce the mislocations of large magnitude
and/or superficial earthquakes in the southernmost Calabria and Messina Strait and of low magnitude and/or
deep earthquakes in north-eastern Sicily. The major accuracy of synthetic earthquake locations obtained
including OBS/H data provides an additional support to the interpretation of the cluster occurred in March
2001 and to the opportunity of long-term installation of an off-shore network like TYDE in the study region
Volcanic tremor at Mt. Etna, Italy, preceding and accompanying the eruption of July-August, 2001
The July 17 – August 9, 2001 flank eruption of Mt. Etna was preceded and accompanied
by remarkable changes in volcanic tremor. Based on the records of stations belonging to the permanent
seismic network deployed on the volcano, we analyze amplitude and frequency content of the seismic
signal. We find considerable changes in the volcanic tremor which mark the transition to different styles of
eruptive activity, e.g., lava fountains, phreatomagmatic activity, Strombolian explosions. In particular, the
frequency content of the signal decreases from 5 Hz to 3 Hz at our reference station ETF during episodes
of lava fountains, and further decreases at about 2 Hz throughout phases of intense lava emission. The
frequency content and the ratios of the signal amplitude allow us to distinguish three seismic sources, i.e.,
the peripheral dike which fed the eruption, the reservoir which fed the lava fountains, and the central
conduit. Based on the analysis of the amplitude decay of the signal, we highlight the migration of the dike
from a depth of ca. 5 km to about 1 km between July 10 and 12. After the onset of the effusive phase, the
distribution of the amplitude decay at our stations can be interpreted as the overall result of sources
located within the first half kilometer from the surface. Although on a qualitative basis, our findings shed
some light on the complex feeding system of Mt. Etna, and integrate other volcanological and geophysical
studies which tackle the problem of magma replenishment for the July–August, 2001 flank eruption. We
conclude that volcanic tremor is fundamental in monitoring Mt. Etna, not only as a marker of the different
sources which act within the volcano edifice, but also of the diverse styles of eruptive activity
Электрошлаковая наплавка биметаллических заготовок червячных колес
Background The oestrogen receptor (ER) co-activator amplified in breast cancer 1 (AIB1) has been suggested as a treatment predictive and prognostic marker in breast cancer. Studies have however not been unanimous. Patients and methods AIB1 protein expression was analysed by immunohistochemistry on tissue micro-arrays with tumour samples from 910 postmenopausal women randomised to tamoxifen treatment or no adjuvant treatment. Associations between AIB1 expression, clinical outcome in the two arms and other clinicopathological variables were examined. Results In patients with ER-positive breast cancer expressing low tumour levels of AIB1 (<75%), we found no significant difference in recurrence-free survival (RFS) or breast cancer-specific survival (BCS) between tamoxifen treated and untreated patients. In patients with high AIB1 expression (>75%), there was a significant decrease in recurrence rate (HR 0.40, 95% CI 0.26–0.61, P < 0.001) and breast cancer mortality rate (HR 0.38, 95% CI 0.21–0.69, P = 0.0015) with tamoxifen treatment. In the untreated arm, we found high expression of AIB1 to be significantly associated with lower RFS (HR 1.74, 95% CI 1.20–2.53, P = 0.0038). Conclusion Our results suggest that high AIB1 is a predictive marker of good response to tamoxifen treatment in postmenopausal women and a prognostic marker of decreased RFS in systemically untreated patients.Funding Agencies|Swedish Cancer Society|110504|Swedish Research Council|B0771901|</p
Observing Volcanoes from the Seafloor in the Central Mediterranean Area
The three volcanoes that are the object of this paper show different types of activity that are representative of the large variety of volcanism present in the Central Mediterranean area. Etna and Stromboli are sub-aerial volcanoes, with significant part of their structure under the sea, while the Marsili Seamount is submerged, and its activity is still open to debate. The study of these volcanoes can benefit from multi-parametric observations from the seafloor. Each volcano was studied with a different kind of observation system. Stromboli seismic recordings are acquired by means of a single Ocean Bottom Seismometer (OBS). From these data, it was possible to identify two different magma chambers at different depths. At Marsili Seamount, gravimetric and seismic signals are recorded by a battery-powered multi-disciplinary observatory (GEOSTAR). Gravimetric variations and seismic Short Duration Events (SDE) confirm the presence of hydrothermal activity. At the Etna observation site, seismic signals, water pressure, magnetic field and acoustic echo intensity are acquired in real-time thanks to a cabled multi-disciplinary observatory (NEMO-SN1 ). This observatory is one of the operative nodes of the European Multidisciplinary Seafloor and water-column Observatory (EMSO; www.emso-eu.org) research infrastructure. Through a multidisciplinary approach, we speculate about deep Etna sources and follow some significant events, such as volcanic ash diffusion in the seawater
The monitoring of seismic activity at Nyiragongo volcano through telemetered seismic network Goma Volcano Observatory (Democratic Republic of the Congo)
The eruption, in January 2002, of Mount Nyiragongo in eastern Congo, and the humanitarian disaster that followed in its wake, underlined the critical importance of accurate seismology to predict when such events will take place. Thus, a seismic telemeterd network, with centre in Goma Observatory, was built across Virunga area to help the moniotring of Volcano.
Mount Nyiragongo is a volcano in the Virunga Mountains associated with the Great Rift Valley. The most prominent feature of the Democratic Republic of Congo's geology is the Western Rift Zone (WRZ), which runs through its eastern border regions and neighbouring countries (e.g. Uganda, Rwanda, Burundi, Tanzania) between 28°E to 32°E and 4°N to 12°S. The WRZ extends over a 1600 km arc, including lakes Albert, Eduard, Kivu and Tanganyika, until it joins the eastern branch. The Western Rift Valley of Africa has experienced severe earthquakes and volcanic eruptions in recent historical times. Earthquakes with magnitude >=6 are not frequent, but may cause significant destruction. They occur mostly in DRC and neighbouring countries (e.g. Uganda and Tanzania). In 1991, IAVCEI selected the Nyiragongo volcano as the ‘African decade volcano’ for the International Decade of Natural Disaster Reduction (IDNDR) program. Nyiragongo is located about 20 km north of Lake Kivu and 15 km north of Goma, a city of about 500,000 inhabitants. Goma is twinned to Gisenyi in Rwanda, which has a population of about 100,000. Several small villages are also located on the flank of the volcano. Population growth and poor or non-existent planning has led to relatively uncontrolled use of land for building, and the development of sites vulnerable to earthquake and/or volcanic risk.EUROPEAN CENTER FOR GEODYNAMICS AND SEISMOLOGY
Royal Museum for Central Africa, B
National Museum of Nat. History, LUnpublishedLuxembourg1.4. TTC - Sorveglianza sismologica delle aree vulcaniche attiveope
Markers for the identification of late breast cancer recurrence
This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly credited
- …