239 research outputs found
Ground motion models for Molise region (Southern Italy)
On October 31st and November 1st, 2002 two moderate earthquakes of moment magnitude Mw=5.7 (INGV-Harvard European-Mediterranean Regional Centroid-Moment tensor project) occurred in southern Italy. After the mainshocks, felt in many municipalities of the Molise and Puglia region, a strong motion and a seismic temporary network were installed in the epicentral area and surrounding regions. The strong motion network was composed by 9 stations, integrating the accelerometers of the permanent Rete Accelerometrica Nazionale (RAN network), and operated until December 2003. The strong motion data set is composed by 195 recordings from 51 earthquakes (2.5<Ml<5.4) recorded by 29 accelerometers (Dipartimento della Protezione Civile et al., 2004). In addition to the strong motion network, several Italian research institutions (Istituto Nazionale di Geofisica e Vulcanologia, INGV; Istituto Nazionale di Oceanografia e Geofisica, INOGS; Dipartimento per lo studio del Territorio e delle sue Risorse, University of Genoa, Dip.Te.Ris) installed a temporary regional network, composed by 35 seismic stations. This network aimed at monitoring and studying the evolution in time and space of the seismic sequence. More than 1900 aftershocks were recorded in the period November 1st - December 5th, 2002 (Chiarabba et al., 2005).
The unified velocity-acceleration data set has been considered to derive ground motion models for peak ground acceleration and peak ground velocity for both maximum horizontal and vertical components. The results obtained for the Molise area have been compared with the attenuation pattern of the Umbria-Marche region (central Italy), that was recently investigated by Bindi et al. (2006). The remarkable differences observed indicate the need of a regional attenuation relation for the area and the need of further investigations, to better identify the role of source characteristics, anelastic and geometric attenuation and site effects in the evaluation of peak ground motion values
Study of an advanced General Aviation Turbine Engine (GATE)
The best technology program for a small, economically viable gas turbine engine applicable to the general aviation helicopter and aircraft market for 1985-1990 was studied. Turboshaft and turboprop engines in the 112 to 746 kW (150 to 1000 hp) range and turbofan engines up to 6672 N (1500 lbf) thrust were considered. A good market for new turbine engines was predicted for 1988 providing aircraft are designed to capitalize on the advantages of the turbine engine. Parametric engine families were defined in terms of design and off-design performance, mass, and cost. These were evaluated in aircraft design missions selected to represent important market segments for fixed and rotary-wing applications. Payoff parameters influenced by engine cycle and configuration changes were aircraft gross mass, acquisition cost, total cost of ownership, and cash flow. Significant advantage over a current technology, small gas turbine engines was found especially in cost of ownership and fuel economy for airframes incorporating an air-cooled high-pressure ratio engine. A power class of 373 kW (500 hp) was recommended as the next frontier for technology advance where large improvements in fuel economy and engine mass appear possible through component research and development
Coastal vulnerability assessment: through regional to local downscaling of wave characteristics along the Bay of Lalzit (Albania)
Coastal vulnerability is
evaluated against inundation risk triggered by wave run-up through the
evaluation of vulnerability levels (referred to as VLs) introduced by
Bosom and Jiménez (2011). VLs are assessed through different wave climate
characterizations, referring to regional (offshore wave climate) or local
(nearshore wave climate) scales. The study is set along the Bay of Lalzit, a
coastal area near Durrës (Albania). The analysis reveals that the results
vary due to uncertainties inherent in the run-up estimation, showing that the
computational procedure should be developed by taking into account detailed
information about the local wave climate. Different approaches in choosing
wave characteristics for run-up estimation significantly affect the estimate
of shoreline vulnerability. The analysis also shows the feasibility and
challenges of applying VL estimates in contexts characterized by limited data
availability through targeted field measurements of the coast geomorphology
and an overall understanding of the recent coastal dynamics and related
controlling factors.</p
Task 3 - Molise - Deliverable D7: Validation shaking scenarios.
The main goal of this report is the computation of the bedrock seismic motion at 5
municipalities located in the Molise area (Bonefro, S.Giuliano, Colletorto, S.Croce di
Magliano, Ripabottoni, hereafter referred to as sites BNF, SGI, CLT, SCM and RPB,
respectively). This area represents one of the validation case studies, planned in the
framework of Project S3 which aim is the production of ground shaking scenarios for
moderate magnitude earthquakes. Indeed, the recently occurred Molise earthquake
represents a proper opportunity to compare synthetic simulations with real data.
Acceleration time series were recorded during the October 31, 2002 and November 1,
2002 main shocks by analog and digital instruments managed by the Italian Civil
Protection Department [DPC-SSN, 2004] while acceleration and velocity records
were collected during the first month of seismic activity by DPC, INGV, INOGS,
Dip.Te.Ris.(Genoa) (see §2.1 and Deliverable D6). Both strong and weak motion data
were employed to infer regional ground motion prediction equations and spectral
attenuation models (§2.3 and §2.4) while acceleration time series recorded during the
first main shock by nearby stations were used to constrain the seismogenic sources
of the October 31 and November 1, 2002 twin earthquakes (§4.1).
Bedrock shaking scenarios at different level of complexity were produced by ground
motion prediction equations (scenarios of level 0, §4.2), high frequency (f>1Hz)
simulations (scenarios of level I, §4.3) and broad band (0-12 Hz) simulations
(scenarios of level II, §4.4). Comparison of results obtained with different simulations
methods confirms the complexity of the Molise area as regard to both seismogenic
and attenuation properties of the crust. Especially for this area the ground motion
prediction is constrained by the demand of simulations reproducing different
features of the seismic wavefield. In particular, the input motion for site effect
modelling, performed at sites located in the epicentral area, was computed with a
broad band technique able to reproduce the complete wave field in the frequency
band 0-10 Hz in terms of acceleration time series (scenarios of level II scenarios)
Predictors of compliance with higher dose omega-3 fatty acid supplementation during pregnancy and implications for the risk of prematurity: exploratory analysis of the ORIP randomised trial
Background: Intention-to-treat analyses of the Omegaâ3 to Reduce the Incidence of Prematurity (ORIP) trial found that omega-3 (n-3) fatty acid supplementation reduces the risk of prematurity in the subgroup of women with a singleton pregnancy and low n-3 status early in pregnancy, but not overall. However, results may have been influenced by less-than-optimal compliance. Objectives: To identify predictors of compliance with n-3 supplementation and determine treatment effects among compliers. Design: Exploratory analyses of a multicentre-blinded randomised trial. Setting: 6 tertiary care centres in Australia. Participants: 5328 singleton pregnancies. Interventions: Daily capsules containing 900âmg n-3 long-chain polyunsaturated fatty acids or vegetable oil, consumed from before 20 weeks gestation until 34 weeks gestation. Outcome measures: Early preterm (<34 weeks gestation) and preterm birth (<37 weeks gestation). Women were considered compliant if they reported missing less than a third of their allocated capsules in the previous week during a mid-pregnancy appointment. Results: Among 2654 singleton pregnancies in the n-3 intervention group, 1727 (65%) were deemed compliant with supplementation. Maternal characteristics associated with compliance included age, years of full-time education, consuming alcohol but not smoking in the 3 months leading up to pregnancy, fewer previous births and taking dietary supplements at enrolment. Based on complier average causal effects, n-3 supplementation reduced the risk of preterm birth in compliers (relative risk=0.76; 95%âCI 0.60 to 0.97), but not early preterm birth (relative risk=0.80; 95%âCI 0.44 to 1.46). Consistent with intention-to-treat analyses, the lack of an overall effect on early preterm birth in compliers appeared to be due to beneficial effects in women with low n-3 status at enrolment but not women with replete status. Conclusions: Results in compliers were similar to those from intention-to-treat analyses, suggesting that non-compliance was not a major factor in explaining outcomes from the ORIP trial. Trial registration number: ACTRN12613001142729.Thomas R Sullivan, Lisa N Yelland, Robert A Gibson, Sagar K Thakkar, Fang Huang, Karen P Best, Surabhi Devaraj, Irma Silva Zolezzi, Maria Makride
SMART Research: Toward Interdisciplinary River Science in Europe
Interdisciplinary science is rapidly advancing to address complex human-environment
interactions. River science aims to provide the methods and knowledge required to
sustainably manage some of the planetâs most important and vulnerable ecosystems;
and there is a clear need for river managers and scientists to be trained within an
interdisciplinary approach. However, despite the science communityâs recognition of the
importance of interdisciplinary training, there are few studies examining interdisciplinary
graduate programs, especially in science and engineering. Here we assess and
reflect on the contribution of a 9-year European doctoral program in river science:
âScience for MAnagement of Rivers and their Tidal Systemsâ Erasmus Mundus Joint
Doctorate (SMART EMJD). The program trained a new generation of 36 early career
scientists under the supervision of 34 international experts from different disciplinary
and interdisciplinary research fields focusing on river systems, aiming to transcend
the boundaries between disciplines and between science and management. We
analyzed the three core facets of the SMART program, namely: (1) interdisciplinarity,
(2) internationalism, and (3) management-oriented science. We reviewed the contents
of doctoral theses and publications and synthesized the outcomes of two questionnaire
surveys conducted with doctoral candidates and supervisors. A high percentage of the
scientific outputs (80%) were interdisciplinary. There was evidence of active collaboration
between different teams of doctoral candidates and supervisors, in terms of joint
publications (5 papers out of the 69 analyzed) but this was understandably quite
limited given the other demands of the program. We found evidence to contradict
the perception that interdisciplinarity is a barrier to career success as employment
rates were high (97%) and achieved very soon after the defense, both in academia
(50%) and the private/public sector (50%) with a strong international dimension. Despite
management-oriented research being a limited (9%) portion of the ensemble of theses, employment in management was higher (22%). The SMART program also increased
the network of international collaborations for doctoral candidates and supervisors.
Reflections on doctoral training programs like SMART contribute to debates around
research training and the career opportunities of interdisciplinary scientists
Identifying women who may benefit from higher dose omega-3 supplementation during pregnancy to reduce their risk of prematurity: exploratory analyses from the ORIP trial.
OBJECTIVES: The risk factors for prematurity are multifactorial and include low omega-3 status. Omega-3 supplementation in pregnancy has been found to reduce prematurity risk, particularly among women with low omega-3 levels. This study aimed to identify maternal characteristics that predict whether women with a singleton pregnancy will benefit from omega-3 supplementation to reduce their risk of prematurity. DESIGN: Exploratory analyses of a multicentre, double-blind randomised trial. SETTING: 6 tertiary care centres in four states in Australia. PARTICIPANTS: 5328 singleton pregnancies in 5305 women recruited before 20 weeks of gestation. INTERVENTIONS: Fish oil capsules containing 900 mg omega-3 long-chain polyunsaturated fatty acids per day versus vegetable oil capsules consumed from enrolment until 34 weeks' gestation. OUTCOME MEASURES: Early preterm birth (EPTB, <34 weeks' gestation) and preterm birth (PTB, <37 weeks' gestation) analysed using logistic regression models with interactions between treatment group and a range of maternal biological, clinical and demographic characteristics. RESULTS: Omega-3 supplementation reduced the odds of EPTB for women with low total omega-3 status in early pregnancy (OR=0.30, 95% CI 0.10-0.93). No additional maternal characteristics influenced whether omega-3 supplementation reduced the odds of EPTB. For PTB, women were more likely to benefit from omega-3 supplementation if they were multiparous (OR=0.65, 95% CI 0.49-0.87) or avoided alcohol in the lead up to pregnancy (OR=0.62, 95% CI 0.45-0.86). CONCLUSIONS: Our results support previous findings that women with low total omega-3 levels in early pregnancy are most likely to benefit from taking omega-3 supplements to reduce their risk of EPTB. Understanding how other maternal characteristics influence the effectiveness of omega-3 supplementation on reducing PTB requires further investigation. TRIAL REGISTRATION NUMBER: ACTRN12613001142729.Lisa N Yelland, Thomas R Sullivan, Robert A Gibson, Lucy A Simmonds, Sagar K Thakkar, Fang Huang, Surabhi Devaraj, Karen P Best, Irma Silva Zolezzi, Maria Makride
A review of assessment methods for river hydromorphology
The work leading to this paper has received funding for the EUâs FP7 under Grant Agreement No. 282656 (REFORM
Convective nature of planimetric instability in meandering river dynamics
The convective nature of the linear instability of meandering river dynamics is analytically demonstrated and the corresponding Green's function is derived. The wave packet due to impulsive disturbance migrates along a river either downstream or upstream, depending on the subresonant or superresonant conditions. The influence of the parameters that govern the meandering process is shown and the role of the fluid dynamic detail used to describe the morphodynamic problem is discussed. A numerical simulation of the river planimetry is also develope
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