Bounding normalization time through intersection types

Non-idempotent intersection types are used in order to give a bound of the length of the normalization beta-reduction sequence of a lambda term: namely, the bound is expressed as a function of the size of the term.Comment: In Proceedings ITRS 2012, arXiv:1307.784

Modelling of priority pollutants releases from urban areas

In the framework of the EU project ScorePP (Source Control Options for Reducing Emissions of Priority Pollutants), dynamic PPs (priority pollutants) fate models are being developed to assess appropriate strategies for limiting the release of PPs from urban sources and for treating PPs on a variety of spatial scales. Different possible sources of PP releases were mapped and both their release pattern and their loads were quantified as detailed as possible. This paper focuses on the link between the gathered PP sources data and the dynamic models of the urban environment. This link consists of: (1) a method for the quantitative and structured storage of temporal emission pattern information, (2) the coupling of GIS-based spatial emission source data with temporal emission pattern information and (3) the generation of PP release time series to feed the dynamic sewer catchment model. Steps 2 and 3 were included as the main features of a dedicated software tool. Finally, this paper also illustrates the method’s applicability to generate model input timeseries for generic pollutants (N, P and COD/BOD) in addition to priority pollutants

Sergio de Benedetti Manuscript (English translation)

The autobiography of a young physicist who left Italy after the passage of the Racial Laws in 1938. Written in 1941, this account covers the tumultuous years between the two world wars. English translation.https://digitalcommons.chapman.edu/debenedetti/1001/thumbnail.jp

Tousled kinase TLK1B counteracts the effect of Asf1 in inhibition of histone H3–H4 tetramer formation

<p>Abstract</p> <p>Background</p> <p>The <it>T</it>ousled-<it>l</it>ike <it>k</it>inases (TLKs) function in processes of chromatin assembly, including replication, transcription, repair, and chromosome segregation. TLK1 interacts specifically with the chromatin assembly factor Asf1, a histone H3–H4 chaperone, and with Rad9, a protein involved in DNA repair. Asf1 binds to the H3–H4 dimer at the same interface that is used for formation of the core tetramer, and hence Asf1 is implicated in disruption of the tetramer during transcription, although Asf1 also has a function in chromatin assembly during replication and repair.</p> <p>Findings</p> <p>We have used protein crosslinking with purified components to probe the interaction between H3, H4, Asf1, and TLK1B. We found that TLK1B, by virtue of its binding to Asf1, can restore formation of H3–H4 tetramers that is sterically prevented by adding Asf1.</p> <p>Conclusion</p> <p>We suggest that TLK1B binds to Asf1 in a manner that interferes with its binding to the H3–H4 dimer, thereby allowing for H3–H4 tetramerization. A description of the function of TLK1 and Asf1 in chromatin remodeling is presented.</p

Guerra y excedente social

El presente trabajo describe los debates en torno a la existencia o inexistencia de guerra en las sociedades primitivas intentado sistematizar las diferentes nociones relativas a la guerra en la prehistoria y en la antigüedad tardía. El registro arqueológico muestra de manera inequívoca la existencia de guerra desde el neolítico y, de manera aún más inequívoca, desde la Revolución Neolítica2 es decir con el surgimiento de la agricultura, las ciudades, la escritura, la estratificación social, el Estado y las religiones institucionalizadas. Todas la teorías disponibles sobre los inicios de la civilización enfatizas que o bien los cambios fueron producidos por la creación de una economía excedentaria o, a lo sumo, esta economía fue la condición de posibilidad para la creación de la civilización. Dentro de los cambios que operaron en la revolución neolítica aparece de manera inequívoca la existencia de la guerra. La construcción de murallas, de armamento específicamente orientado al enfrentamiento con otros humanos (cascos, escudos, etc.), demuestran que la guerra era una actividad recurrente en dichas sociedades. La existencia de guerra con anterioridad al neolítico, es decir durante el paleolítico, es una cuestión en la que el registro arqueológico es bastante equívoco y donde se encuentran lo más enconados debates.Mesa 21: Aportes para una sociología de la guerra. La guerra como objeto de estudio de las ciencias humanas. Problemas teóricos y abordajes de conflictos concretos, de la antigüedad al presente.Facultad de Humanidades y Ciencias de la Educació

Real-time monitoring of proton exchange membrane fuel cell stack failure

Uneven pressure drops in a 75-cell 9.5-kWe proton exchange membrane fuel cell stack with a U-shaped flow configuration have been shown to cause localised flooding. Condensed water then leads to localised cell heating, resulting in reduced membrane durability. Upon purging of the anode manifold, the resulting mechanical strain on the membrane can lead to the formation of a pin-hole/membrane crack and a rapid decrease in open circuit voltage due to gas crossover. This failure has the potential to cascade to neighbouring cells due to the bipolar plate coupling and the current density heterogeneities arising from the pin-hole/membrane crack. Reintroduction of hydrogen after failure results in cell voltage loss propagating from the pin-hole/membrane crack location due to reactant crossover from the anode to the cathode, given that the anode pressure is higher than the cathode pressure. Through these observations, it is recommended that purging is avoided when the onset of flooding is observed to prevent irreparable damage to the stack

Spatial structures and dynamics of kinetically constrained models for glasses

Kob and Andersen's simple lattice models for the dynamics of structural glasses are analyzed. Although the particles have only hard core interactions, the imposed constraint that they cannot move if surrounded by too many others causes slow dynamics. On Bethe lattices a dynamical transition to a partially frozen phase occurs. In finite dimensions there exist rare mobile elements that destroy the transition. At low vacancy density, $v$, the spacing, $\Xi$, between mobile elements diverges exponentially or faster in $1/v$. Within the mobile elements, the dynamics is intrinsically cooperative and the characteristic time scale diverges faster than any power of $1/v$ (although slower than $\Xi$). The tagged-particle diffusion coefficient vanishes roughly as $\Xi^{-d}$.Comment: 4 pages. Accepted for pub. in Phys. Rev. Let