Folding protein models with a simple hydrophobic energy function: The fundamental importance of monomer inside/outside segregation

The present study explores a “hydrophobic” energy function for folding simulations of the protein lattice model. The contribution of each monomer to conformational energy is the product of its “hydrophobicity” and the number of contacts it makes, i.e., E(h⃗, c⃗) = −Σi=1N cihi = −(h⃗.c⃗) is the negative scalar product between two vectors in N-dimensional cartesian space: h⃗ = (h1, … , hN), which represents monomer hydrophobicities and is sequence-dependent; and c⃗ = (c1, … , cN), which represents the number of contacts made by each monomer and is conformation-dependent. A simple theoretical analysis shows that restrictions are imposed concomitantly on both sequences and native structures if the stability criterion for protein-like behavior is to be satisfied. Given a conformation with vector c⃗, the best sequence is a vector h⃗ on the direction upon which the projection of c⃗ − c̄⃗ is maximal, where c̄⃗ is the diagonal vector with components equal to c̄, the average number of contacts per monomer in the unfolded state. Best native conformations are suggested to be not maximally compact, as assumed in many studies, but the ones with largest variance of contacts among its monomers, i.e., with monomers tending to occupy completely buried or completely exposed positions. This inside/outside segregation is reflected on an apolar/polar distribution on the corresponding sequence. Monte Carlo simulations in two dimensions corroborate this general scheme. Sequences targeted to conformations with large contact variances folded cooperatively with thermodynamics of a two-state transition. Sequences targeted to maximally compact conformations, which have lower contact variance, were either found to have degenerate ground state or to fold with much lower cooperativity.

Erratum: Suppression of localization in kronig-penney models with correlated disorder (Vol. 49, PG 147, 1994)

We consider the electron dynamics and transport properties of one-dimensional continuous models with random, short-range correlated impurities. We develop a generalized Poincare map formalism to cast the Schrodinger equation for any potential into a discrete set of equations, illustrating its application by means of a specific example. We then concentrate on the case of a Kronig-Penney model with dimer impurities. The previous technique allows us to show that this model presents infinitely many resonances (zeroes of the reflection coefficient at a single dimer) that give rise to a band of extended states, in contradiction with the general viewpoint that all one-dimensional models with random potentials support only localized states. We report on exact transfer-matrix numerical calculations of the transmission coefFicient, density of states, and localization length for various strengths of disorder. The most important conclusion so obtained is that this kind of system has a very large number of extended states. Multifractal analysis of very long systems clearly demonstrates the extended character of such states in the thermodynamic limit. In closing, we brieBy discuss the relevance of these results in several physical contexts.

Fundamental Rights of workers in the Digital Age: A methodological approach from a case study. WP C.S.D.L.E. "Massimo D'Antona" .INT - 89/2011

The relationship between employer and worker is not only obligatory but above all, as Sinzheimer said, a ‘relationship of power’. In the Digital Age this statement is confirmed by the massive introduction of ICT in most of the companies that increase, in practice, employer’s supervisory powers. This is a worrying issue for two reasons: on one hand, ICT emerge as a new way to weaken the effectiveness of fundamental rights and the right to dignity of workers; and, on the other hand, Spanish legal system does not offer appropriate solutions to ensure that efficacy. Moreover, in a scenario characterized by a hybridization of legal systems models –in which traditional hard law methods are combined with soft law and self regulation instruments–, the role of our case law has become very important in this issue. Nevertheless, despite the increase of judicialization undergone, solutions offered by Courts are so different that do not give enough legal certainty. Facing this situation, I suggest a methodological approach –using Alchourron and Bulygin’s normative systems theory and Alexy’s fundamental rights theory– which can open new spaces of decision to legal operators in order to solve properly these problems. This proposal can allow setting a policy that guarantees fundamental rights of workers, deepening their human freedom in companies from the Esping-Andersen’s de-commodification perspective. With this purpose, I examine electronic communications in the company as a case study.

Whole rock analytical techniques and glas analytical techniques of silicic magmas from the South East Rift, Manus Basin

There has been much recent interest in the origin of silicic magmas at spreading centres away from any possible influence of continental crust. Here we present major and trace element data for 29 glasses (and 55 whole-rocks) sampled from a 40 km segment of the South East Rift in the Manus Basin that span the full compositional continuum from basalt to rhyolite (50-75 wt % SiO2). The glass data are accompanied by Sr-Nd-Pb, O and U-Th-Ra isotope data for selected samples. These overlap the ranges for published data from this part of the Manus Basin. Limited increases in Cl/K ratios with increasing SiO2, La-SiO2 and Yb-SiO2 relationships, and the oxygen isotope data rule out models in which the more silicic lavas result from partial melting of altered oceanic crust or altered oceanic gabbros. Rather, the data form a coherent array that is suggestive of closed-system fractional crystallization and this is well simulated by MELTS models run at 0.2 GPa and QFM (quartz-fayalite-magnetite buffer) with 1 wt % H2O, using a parental magma chosen from the basaltic glasses. Although some assimilation of altered oceanic crust or gabbro cannot be completely ruled out, there is no evidence that this plays an important role in the origin of the silicic lavas. The U-series disequilibria are dominated by 238U and 226Ra excesses that limit the timescale of differentiation to less than a few millennia. Overall, the data point to rapid evolution in relatively small magma lenses located near the base of thick oceanic crust; we speculate that this was coupled with relatively low rates of basaltic recharge. A similar model may be applicable to the generation of silicic magmas elsewhere in the ocean basins.

Concepts and techniques of machine safeguarding.

Shipping list no.: 92-486-P.

Principles and techniques of drug recognition expert training. The DRE Instructor Training School teacher-trainer manual.

National Highway Traffic Safety Administration, Washington, D.C.

Principles and techniques of drug recognition expert training. The DRE Instructor Training School student-instructor manual.

National Highway Traffic Safety Administration, Washington, D.C.

Fundamental study of creep-rupture under combined stress /

"Contract AT(11-1)-229."

Techniques of dairy plant testing.

Includes bibliography.

Some fundamental principles of metabolism

Mode of access: Internet.

Getting started with power tools; a basic readily understandable book on the fundamental operations of power-tool equipment.

Mode of access: Internet.

Variational and Lagrangian thermodynamics of thermal convection-- fundamental shortcomings of the heat-transfer coefficient.

Mode of access: Internet.

The absorption refrigerating machine, elementary theory and practice, a complete practical elementary treatise on the absorption system of refrigeration, and its general fundamental principles of operation.

Mode of access: Internet.