789 research outputs found
Variational calculations for K-few-nucleon systems
Deeply bound KNN, KNNN and KNNNN states are discussed. The effective force
exerted by the K meson on the nucleons is calculated with static nucleons. Next
the binding energies are obtained by solving the Schrodinger equation or by
variational calculations.
The dominant attraction comes from the S-wave Lambda(1405) and an additional
contribution is due to Sigma(1385). The latter state is formed at the nuclear
peripheries and absorbs a sizable piece of the binding energy. It also
generates new branches of quasi-bound states. The lowest binding energies based
on a phenomenological KN input fall into the 40-80 MeV range for KNN, 90-150
MeV for KNNN and 120-220 MeV for K-alpha systems. The uncertainties are due to
unknown KN interactions in the distant subthreshold energy region.Comment: 19 pages, 1 figur
Social media in/and the politics of the European Union: Politico-organizational communication, institutional cultures and self-inflicted elitism
This paper looks at how social/online media – using the example of Twitter – are used in the politico-organizational communication of the European Union at a time when it faces multiple crises and is in acute need of effectively communicating its politics to the European demos. Proposing a critical discourse framework for the analysis of the politico-organizational use of Twitter, the paper shows that while, to some extent, bringing change or ‘modernization’ to EU political communication patterns, social/online media help in sustaining some of the deep-seated dispositions in EU communicative and organizational practices as well as political discourses. As deployed by the EU’s – and specifically the European Commission’s – spokesperson service, social/online help in solidifying some of the controversial patterns in EU political communication. They also bring in other, more contemporary, challenges as regards using Twitter and social media as parts of political and institutional/organizational communication
PF191012 Myszyniec - highest Orionid meteor ever recorded
On the night of Oct 18/19, 2012 at 00:23 UT a -14.7 mag Orionid fireball
occurred over northeastern Poland. The precise orbit and atmospheric trajectory
of the event is presented, based on the data collected by five video and one
photographic Polish Fireball Network (PFN) stations. The beginning height of
the meteor is 168.4 +\- 0.6 km which makes the PF191012 Myszyniec fireball the
highest ever observed, well documented meteor not belonging to the Leonid
shower. The ablation became the dominant source of light of the meteor at a
height of around 115 km. The thermalization of sputtered particles is suggested
to be the source of radiation above that value. The transition height of 115 km
is 10-15 km below the transition heights derived for Leonids and it might
suggest that the material of Leonids should be more fragile and have probably
smaller bulk density than in case of Orionids.Comment: 5 pages, 5 figures, accpeted for publication in Astronomy &
Astrophysic
Identification of novel stem cell markers using gap analysis of gene expression data
A method for the detection of marker genes in large heterogeneous collections of gene expression data is described and applied to DNA microarray data generated from 83 mouse stem cell-related samples
Epidemiologic studies on short-term effects of low levels of major ambient air pollution components.
Since the development of the World Health Organization (WHO) Air Quality Guidelines for Europe, a large number of epidemiologic studies have been published documenting effects of major air pollutants on health at concentrations below existing guidelines and standards. In this review, recent studies are discussed that permit some evaluation of short-term health effects observed at exposure levels lower than the current WHO Guidelines or U.S. Environmental Protection Agency (U.S. EPA) standards. Some studies have been conducted at concentration levels that never exceeded existing guidelines or standards. Other studies have been conducted at exposure levels sometimes exceeding current guidelines or standards. The published analyses of several of these studies permit evaluation of low-level health effects either because analyses were restricted to levels not exceeding the guidelines or graphic analyses were reported suggesting effects at these low levels. For ambient ozone, effects on lung function of subjects exercising outdoors have now been documented at 1-hr maximum levels not exceeding 120 micrograms/m3, i.e., half the current U.S. EPA standard. One study even suggests that such effects occur at levels below 100 micrograms/m3. Several studies are now available documenting effects of particulate air pollution on health in the virtual absence of SO2. Effects on mortality and hospital admissions for asthma have been documented at levels not exceeding 100 micrograms/m3, expressed as 24-hr average inhalable particles PM10 concentration. Effects on lung function, acute respiratory symptoms, and medication use have been found at 24-hr average PM10 levels not exceeding 115 micrograms/m3. When the WHO Air Quality Guidelines and the U.S. EPA standard for PM10 were developed, there were no studies available on health effects of PM10. In this review, we include nine studies documenting health effects of measured PM10 at low levels of exposure, indicating that there is now an entirely new epidemiologic database that can be evaluated in the process of revising current guidelines and standards. The low levels of exposure at which effects on health were seen underscore the urgent need for such reevaluations
Análise de lignina com diferentes massas de tegumento de soja utilizando método gravimétrico.
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