971 research outputs found
The Seiberg-Witten Map for Noncommutative Gauge Theories
The Seiberg-Witten map for noncommutative Yang-Mills theories is studied and
methods for its explicit construction are discussed which are valid for any
gauge group. In particular the use of the evolution equation is described in
some detail and its relation to the cohomological approach is elucidated.
Cohomological methods which are applicable to gauge theories requiring the
Batalin-Vilkoviskii antifield formalism are briefly mentioned. Also, the
analogy of the Weyl-Moyal star product with the star product of open bosonic
string field theory and possible ramifications of this analogy are briefly
mentioned.Comment: 12 pages, talk presented at "Continuous Advances in QCD
2002/Arkadyfest", University of Minnesota, Minneapolis, May 17-23, 2002. A
few misprints correcte
On Intergenerational Transmission of Reading Habits in Italy: Is a Good Example the Best Sermon?
The intergenerational transmission of preference and attitudes has been less investigated in the literature than the intergenerational transmission of education and income. Using the Italian Time Use Survey (2002-2003) conducted by ISTAT, we analyse the intergenerational transmission of reading habits: are children more likely to allocate time to studying and reading when they observe their parents doing the same activity? The intergeneration transmission of attitudes towards studying and reading can be explained by both cultural and educational transmission from parents to children and by imitating behaviours. The latter channel is of particular interest, since it entails a direct influence parents may have on child’s preference formation through their role model, and it opens the scope for active policies aimed at promoting good parents’ behaviours. We follow two fundamental approaches to estimation: a “long run” model, consisting of OLS intergenerational type regressions for the reading habit, and “short run” household fixed effect models, where we aim at identifying the impact of the role model exerted by parents, exploiting different exposure of sibling to parents’ example within the same household. Our long run results show that children are more likely to read and study when they live with parents that are used to read. Mothers seem to be more important than fathers in this type of intergenerational transmission. Moreover, the short run analysis shows that there is an imitation effect: in the day of the survey children are more likely to read after they saw either the mother or the father reading.
Damaging events along roads during bad weather periods: a case study in Calabria (Italy)
The study focuses on circumstances that affect people during periods of bad weather conditions characterised by winds, rainfall, landslides, flooding, and storm surges. A methodological approach and its application to a study area in southern Italy are presented here. A 10-yr database was generated by mining data from a newspaper. Damaging agents were sorted into five types: flood, urban flooding, landslide, wind, and storm surge. Damage to people occurred in 126 cases, causing 13 victims, 129 injured and about 782 people involved but not injured. <br><br> For cases of floods, urban flooding and landslides, the analysis does not highlight straightforward relationships between rainfall and damage to people, even if the events showed different features according to the months of occurrence. The events occurring between May and October were characterised by concentrated and intense rainfall, and between May and July, the highest values of hourly (103 mm on the average) and monthly rainfall (114 mm on the average) were recorded. Urban flooding and flash floods were the most common damaging agents: injured, involved people and more rarely, cases with victims were reported. <br><br> Between November and April, the highest number of events was recorded. Rainfall presented longer durations and hourly and sub-hourly rainfall were lower than those recorded between May and October. Landslides were the most frequent damaging agents but the highest number of cases with victims, which occurred between November and January, were mainly related to floods and urban flooding. <br><br> Motorists represent the totality of the victims; 84% of the people were injured and the whole of people involved. All victims were men, and the average age was 43 yr. The primary cause of death was drowning caused by floods, and the second was trauma suffered in car accidents caused by urban flooding. The high number of motorists rescued in submerged cars reveals an underestimation of danger in the case of floods, often increased by the sense of security related to the familiarity of the road. In contrast, in the cases of people involved in landslides, when there was enough time to realise the potential risk, people behaved appropriately to avoid negative consequences. Of the victims, 50% were killed along fast-flowing roads; this may be related to the high speed limit in force on these roads, as a car's speed reduces the reaction time of a driver's response to an unexpected situation, whatever the damaging agent is. These results can be used in local information/education campaigns to both increase risk awareness and promote self-protective behaviours. <br><br> Moreover, the mapping of damaging effects pointed out the regional sectors in which the high frequency of the events suggests further planning of in-depth examinations, which can individuate the critical points and local regulator interventions that might change damage incidences in the future
Higher order corrections of the extended Chaplygin gas cosmology with varying and
In this paper, we study two different models of dark energy based on
Chaplygin gas equation of state. The first model is the variable modified
Chaplygin gas while the second one is the extended Chaplygin gas. Both models
are considered in the framework of higher order modified gravity. We
also consider the case of time varying gravitational constant and
for both models. We investigate some cosmological parameters such as the
Hubble, the deceleration and the equation of state parameters. Then we showed
that the model that we considered, extended Chaplygin gas with time-dependent
and , is consistent with the observational data. Finally we
conclude with the discussion of cosmological perturbations of our model.Comment: Perturbation analysis added, typos corrected, references adde
Landslide damage assessment using the Support Analysis Framework (SAF): the 2009 landsliding event in Calabria (Italy)
In this paper, a simplified methodological approach is used to assess damage
indices related to landslide phenomena that occurred in Calabria (Italy)
between November 2008 and January 2009. This approach, which was designed
for and applied to single landslides, uses the Support Analysis Framework
(SAF), a procedure containing the elements that can be damaged by a
landslide grouped in categories. In this paper, we test wide-ranging use of
the SAF on a number of landslides, assessing landslide damage on a municipal
scale to get a final estimate of the amount of damage caused by all of the
landslides that occurred in a selected municipality.
<br><br>
Data regarding the damage caused by landslides were gathered from the press.
Daily newspapers were systematically collected and elaborated to assess
direct, indirect and intangible damage caused during the abovementioned
period by a rainfall-triggered <i>landsliding event</i>. In the paper, regional- and
provincial-scale results are described, and the methodological approach is
briefly described.
<br><br>
The application of the proposed methodological approach to the 2009
landsliding event shows that the results can be used to summarise landslide
damage from a complex event in order to better plan an intervention strategy
at a regional, provincial or municipal scale.
<br><br>
The availability of newspaper data during the event and the speed of the
proposed approach allow for rapid location of the damaged sectors during the
event, which will continuously upgrade the regional damage framework. This
can all be done almost in "real time".
<br><br>
For regional agencies, this framework can be a starting point to both manage
the emergency and to acquire and interpret data giving a more detailed
damage distribution so that a response can be organised. Moreover, based on
the damage assessment, a characterisation of the landsliding event can also
be carried out and used to describe the damage scenario occurring after each
type of event
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