2,400 research outputs found
Problems Affecting Labor
Much experimental work has been devoted in comparing the folding behavior of proteins sharing the same fold but different sequence. The recent design of proteins displaying very high sequence identities but different 3D structure allows the unique opportunity to address the protein-folding problem from a complementary perspective. Here we explored by ℙ-value analysis the pathways of folding of three different heteromorphic pairs, displaying increasingly high-sequence identity (namely, 30%, 77%, and 88%), but different structures called G A (a 3-α helix fold) and G B (an α/β fold). The analysis, based on 132 site-directed mutants, is fully consistent with the idea that protein topology is committed very early along the pathway of folding. Furthermore, data reveals that when folding approaches a perfect two-state scenario, as in the case of the G A domains, the structural features of the transition state appear very robust to changes in sequence composition. On the other hand, when folding is more complex and multistate, as for the G Bs, there are alternative nuclei or accessible pathways that can be alternatively stabilized by altering the primary structure. The implications of our results in the light of previous work on the folding of different members belonging to the same protein family are discussed
Investment, Productivity and Employment in the Italian Economy
none3openTRAVAGLINI G.; E. Saltari; C. WymerTravaglini, Giuseppe; E., Saltari; C., Wyme
Resummed spinning waveforms from five-point amplitudes
We compute the classical tree-level five-point amplitude for the two-to-two
scattering of spinning celestial objects with the emission of a graviton. Using
this five-point amplitude, we then turn to the computation of the leading-order
time-domain gravitational waveform. The method we describe is suitable for
arbitrary values of classical spin of Kerr black holes and does not require any
expansion in powers of the spin. In this paper we illustrate it in the simpler
case of the scattering of one Kerr and one Schwarzschild black hole. An
important ingredient of our calculation is a novel form of the Compton
amplitude with spinning particles including contact terms derived from matching
to black-hole perturbation theory calculations. This ensures that our waveform
is valid up to at least fourth order in the spin. Our method can be applied
immediately to generate improved waveforms once higher-order contact terms in
the Compton amplitude become available. Finally, we show the formula for the
gravitational memory to all orders in the spin, which is in agreement with our
results.Comment: 53 pages, 6 figures. v2:typos fixed, references adde
Use of antifuse-FPGAs in the Track-Sorter-Master of the CMS Drift Tube Chambers
The front-end system of the Silicon Drift Detectors (SDDs) of the ALICE experiment is made of two ASICs. The first chip performs the preamplification, temporary analogue storage and analogue-to-digital conversion of the detector signals. The second chip is a digital buffer that allows for a significant reduction of the connection from the front-end module to the outside world. In this paper, the results achieved on the first complete prototype of the front-end system for the SDDs of ALICE are presented
DT Sector Collector electronics design and construction
The CMS detector at LHC is equipped with Drift Tubes (DT) chambers for muon detection and triggering in the barrel region. The Sector Collector (SC) modules collect the track segments reconstructed by on-chamber trigger electronics. Data from different chambers are aligned in time and sent to the subsequent reconstruction processors via optical links. Several FPGA devices performing the processing of the data were designed in VHDL, including spy features to monitor the trigger data flow. A test jig was set up with custom hardware and software in order to fully validate final production boards. Installation and commissioning in CMS provided first experience with the synchronization and monitoring tools
Amplitudes, Hopf algebras and the colour-kinematics duality
It was recently proposed that the kinematic algebra featuring in the
colour-kinematics duality for scattering amplitudes in heavy-mass effective
field theory (HEFT) and Yang-Mills theory is a quasi-shuffle Hopf algebra. The
associated fusion product determines the structure of the
Bern-Carrasco-Johansson (BCJ) numerators, which are manifestly gauge invariant
and with poles corresponding to heavy-particle exchange. In this work we
explore the deep connections between the quasi-shuffle algebra and general
physical properties of the scattering amplitudes. First, after proving the
double-copy form for gravitational HEFT amplitudes, we show that the coproducts
of the kinematic algebra are in correspondence with factorisations of BCJ
numerators on massive poles. We then study an extension of the standard
quasi-shuffle Hopf algebra to a non-abelian version describing BCJ numerators
with all possible gluon orderings. This is achieved by tensoring the original
algebra with a particular Hopf algebra of orderings. In this extended version,
a specific choice of the coproduct in the algebra of orderings leads to an
antipode in the resulting Hopf algebra that has the interpretation of reversing
the gluons' order within each BCJ numerator.Comment: 51 pages, minor corrections, version accepted to JHE
Status and Trend of the Main Allergenic Pollen Grains and Alternaria Spores in the City of Rome (2003-2019)
Today a large part of the European population is exposed to levels of air pollution exceeding the standards recommended by the World Health Organization. Moreover, air pollution and the seasonal emission of allergenic pollen are progressively affecting human health and can cause severe allergic reactions, particularly when air pollution combines with pollen allergen peaks. Unlike atmospheric pollutants of anthropogenic origin, pollen sources have a pulsating trend that leads to high values in the flowering period and values close to, or equal to, zero in the rest of the year. This aspect makes essential the definition of data coverage standards for the main allergenic taxa. For air quality assessment detailed classification criteria for monitoring stations are defined by international standards, not the same from the European Standards for the Sampling and analysis of airborne pollen grains and fungal spores. This paper describes the status and the air concentration trends of the main allergenic pollen and the Alternaria spore measured in Rome from 2003 to 2019 by the Aerobiological Monitoring Center of Tor Vergata (Rome) and calculated by the Seasonal Kendall test with the open-source OpenAir R package. The analysis was carried out on the daily concentrations of the most widespread allergenic taxa in Italy: Asteraceae, Betulaceae, Corylaceae, Cupressaceae/Taxaceae, Poaceae, Oleaceae, Urticaceae and the Alternaria spores
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