A view of canonical extension

This is a short survey illustrating some of the essential aspects of the theory of canonical extensions. In addition some topological results about canonical extensions of lattices with additional operations in finitely generated varieties are given. In particular, they are doubly algebraic lattices and their interval topologies agree with their double Scott topologies and make them Priestley topological algebras.Comment: 24 pages, 2 figures. Presented at the Eighth International Tbilisi Symposium on Language, Logic and Computation Bakuriani, Georgia, September 21-25 200

PROFILES OF RECREATIONAL ACTIVITIES OF DAILY LIVING (RADL) IN PATIENTS WITH MENTAL DISORDERS

Background: Activities of daily living, play a key role in the measurement of functional health as defined by the International Classification of Functioning, Disability and Health (ICF) and in prevention and treatment of mental or somatic illnesses. From a clinical context it is important to discriminate between basic “activities of daily living, ADL”, “intentional activities of daily living, IADL”, and “recreational activities of daily living, RADL”. While ADL and IADL have gained much attention in dementia, the elderly, or severe somatic illnesses, there is a lack of research on RADL, which are important in depression, anxiety, or other neurotic disorders. Subjects and methods: 154 unselected inpatients of a department of behavioral and psychosomatic medicine filled in the “Check List of Recreational Activities” to assess the rates and profiles of RADL. Results: Patients reported on average 19.3 (s.d. 7.0) activities (range 4 – 40), i.e. males 21.3 (s.d. 6.5, 9 – 34) and females 18.9 (s.d. 7.1, 4 – 40). Most frequent RADL were passive and unspecific activities like “watching tv” (93.4%). Least frequent were activities which need special skills or preparation like ”horse back riding” (0.7%). Low rates were also found for activities which are in the centre of inpatient occupational therapy like “ceramics” (4.7%) or “silk-painting” (2.6%). There are differences between sexes but not in respect to age (18 to 60), sick leave and unemployment, or diagnostic status. When patients were asked what they would like to do in the future, the same activity profile emerged as when looking at what they had done in the last month Conclusion: The data give a reference profile for recreational activities, help to define what can be considered a normal frequency and spectrum of RADL, and, by this, can guide therapeutic interventions

PROFILES OF RECREATIONAL ACTIVITIES OF DAILY LIVING (RADL) IN PATIENTS WITH MENTAL DISORDERS

Background: Activities of daily living, play a key role in the measurement of functional health as defined by the International Classification of Functioning, Disability and Health (ICF) and in prevention and treatment of mental or somatic illnesses. From a clinical context it is important to discriminate between basic “activities of daily living, ADL”, “intentional activities of daily living, IADL”, and “recreational activities of daily living, RADL”. While ADL and IADL have gained much attention in dementia, the elderly, or severe somatic illnesses, there is a lack of research on RADL, which are important in depression, anxiety, or other neurotic disorders. Subjects and methods: 154 unselected inpatients of a department of behavioral and psychosomatic medicine filled in the “Check List of Recreational Activities” to assess the rates and profiles of RADL. Results: Patients reported on average 19.3 (s.d. 7.0) activities (range 4 – 40), i.e. males 21.3 (s.d. 6.5, 9 – 34) and females 18.9 (s.d. 7.1, 4 – 40). Most frequent RADL were passive and unspecific activities like “watching tv” (93.4%). Least frequent were activities which need special skills or preparation like ”horse back riding” (0.7%). Low rates were also found for activities which are in the centre of inpatient occupational therapy like “ceramics” (4.7%) or “silk-painting” (2.6%). There are differences between sexes but not in respect to age (18 to 60), sick leave and unemployment, or diagnostic status. When patients were asked what they would like to do in the future, the same activity profile emerged as when looking at what they had done in the last month Conclusion: The data give a reference profile for recreational activities, help to define what can be considered a normal frequency and spectrum of RADL, and, by this, can guide therapeutic interventions

Monotonic Distributive Semilattices

In the study of algebras related to non-classical logics, (distributive) semilattices are always present in the background. For example, the algebraic semantic of the {→, ∧, ⊤}-fragment of intuitionistic logic is the variety of implicative meet-semilattices (Chellas 1980; Hansen 2003). In this paper we introduce and study the class of distributive meet-semilattices endowed with a monotonic modal operator m. We study the representation theory of these algebras using the theory of canonical extensions and we give a topological duality for them. Also, we show how our new duality extends to some particular subclasses.Fil: Celani, Sergio Arturo. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional del Centro de la Provincia de Buenos Aires. Facultad de Ciencias Exactas. Departamento de Matemática; ArgentinaFil: Menchón, María Paula. Universidad Nacional del Centro de la Provincia de Buenos Aires. Facultad de Ciencias Exactas. Departamento de Matemática; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin

Mechanism-Based Redesign of GAP to Activate Oncogenic Ras

Ras GTPases play a crucial role in cell signaling pathways. Mutations of the Ras gene occur in about one third of cancerous cell lines and are often associated with detrimental clinical prognosis. Hot spot residues Gly12, Gly13, and Gln61 cover 97% of oncogenic mutations, which impair the enzymatic activity in Ras. Using QM/MM free energy calculations, we present a two-step mechanism for the GTP hydrolysis catalyzed by the wild-type Ras.GAP complex. We found that the deprotonation of the catalytic water takes place via the Gln61 as a transient Brønsted base. We also determined the reaction profiles for key oncogenic Ras mutants G12D and G12C using QM/MM minimizations, matching the experimentally observed loss of catalytic activity, thereby validating our reaction mechanism. Using the optimized reaction paths, we devised a fast and accurate procedure to design GAP mutants that activate G12D Ras. We replaced GAP residues near the active site and determined the activation barrier for 190 single mutants. We furthermore built a machine learning for ultrafast screening, by fast prediction of the barrier heights, tested both on the single and double mutations. This work demonstrates that fast and accurate screening can be accomplished via QM/MM reaction path optimizations to design protein sequences with increased catalytic activity. Several GAP mutations are predicted to re-enable catalysis in oncogenic G12D, offering a promising avenue to overcome aberrant Ras-driven signal transduction by activating enzymatic activity instead of inhibition. The outlined computational screening protocol is readily applicable for designing ligands and cofactors analogously

Electrical conduction of ion tracks in tetrahedral amorphous carbon: temperature, field and doping dependence and comparison with matrix data

This paper gives an extended overview of the electrical properties of ion tracks in hydrogen-free tetrahedral amorphous carbon (ta-C) with a sp(3) bond fraction of about 80%. The films were grown by mass selected ion beam deposition of 100 eV C-12(+) ions. The ion tracks are generated by irradiation of ta-C films with uranium ions of 1 GeV kinetic energy. Along the ion path a conversion from diamondlike (sp(3)) carbon to graphite-like (sp(2)) carbon takes place. Topography and current measurements of individual ion tracks were performed by atomic force microscopy at ambient temperature. The temperature dependence of the electric conductivity was studied between 15 and 390 K by means of 0.28 mm(2) large contact pads averaging over about 10 7 tracks. For each sample and at each temperature the conductivity as a function of the applied electrical field (non-ohmic behaviour) was measured separately and the data were extrapolated to field zero. In this way, the zero-field conductivity was determined independent from the field dependence. In spite of large differences in the absolute values, the temperature dependence of the zero-field conductivities is found to be very similar in shape for all samples. The conductivities follow a T-1/4 law up to temperatures slightly below room temperature. At higher temperatures a transport mechanism based on over-barrier hopping dominates with an activation energy of about 220 meV for tracks and 260 meV for the ta-C matrix. The field dependence measurements show that the deviation of the I-V characteristics from ohmic behaviour decreases with increasing zero-field conductivity. We also tested Cu-doped ta-C samples and found that they conduct significantly better than pure ta-C. However, the doping also increases the zero-field conductivity resulting in a weaker contrast between the track and matrix. The data are interpreted within the so-called 'barrier model' where the electrons are assumed to move fairly freely in well-conducting sp(2) regions but encounter barriers in track sections consisting of more sp(3)-like bonds

Representation of Nelson Algebras by Rough Sets Determined by Quasiorders

In this paper, we show that every quasiorder $R$ induces a Nelson algebra $\mathbb{RS}$ such that the underlying rough set lattice $RS$ is algebraic. We note that $\mathbb{RS}$ is a three-valued {\L}ukasiewicz algebra if and only if $R$ is an equivalence. Our main result says that if $\mathbb{A}$ is a Nelson algebra defined on an algebraic lattice, then there exists a set $U$ and a quasiorder $R$ on $U$ such that $\mathbb{A} \cong \mathbb{RS}$.Comment: 16 page