The response of the upper atmospheric temperature to changes in solar EUV radiation and geomagnetic activity

Solar radiation and magnetic effects on upper atmospheric neutral temperatures derived from satellite dra

Methodology for testing and validating knowledge bases

A test and validation toolset developed for artificial intelligence programs is described. The basic premises of this method are: (1) knowledge bases have a strongly declarative character and represent mostly structural information about different domains, (2) the conditions for integrity, consistency, and correctness can be transformed into structural properties of knowledge bases, and (3) structural information and structural properties can be uniformly represented by graphs and checked by graph algorithms. The interactive test and validation environment have been implemented on a SUN workstation

Coarsening and Slow-Dynamics in Granular Compaction

We address the problem of the microscopic reorganization of a granular medium under a compaction process in the framework of Tetris-like models. We point out the existence of regions of spatial organization which we call domains, and study their time evolution. It turns out that after an initial transient, most of the activity of the system is concentrated on the boundaries between domains. One can then describe the compaction phenomenon as a coarsening process for the domains, and a progressive reduction of domain boundaries. We discuss the link between the coarsening process and the slow dynamics in the framework of a model of active walkers on active substrates.Comment: Revtex 4 pages, 4 figures, in press in PRL. More info http://axtnt3.phys.uniroma1.it/Tetri

Bott--Kitaev periodic table and index theory

We consider topological insulators and superconductors with discrete symmetries and clarify the relevant index theory behind the periodic table proposed by Kitaev. An effective Hamiltonian determines the analytical index, which can be computed by a topological index. We focus on the spatial dimensions one, two and three, and only consider the bulk theory. In two dimensions, the $\mathbb{Z}$-valued invariants are given by the first Chern number. Meanwhile, $\mathbb{Z}_2$-valued invariants can be computed by the odd topological index and its variations. The Bott-Kitaev periodic table is well-known in the physics literature, we organize the topological invariants in the framework of KR-theory.Comment: 37 page

Correlation between prevalence rates of pulmonary tuberculosis, tuberculous infection and non-specific sensitivity

Data from the initial examination of a BCG trial have been analysed to determine mathematical relationship, if any, between the prevalence of infection and disease. Also, because non-specific sensitivity otters protection against the development of tuberculosis and because there was high prevalence of nonspecific sensitivity in the area of the study, relationship between nonspecific sensitivity and tuberculosis had also been studied. Results of the analysis showed that relationship between prevalence of tuberculous infection and disease is not amenable to any simple mathematical quantification. However, the values of the coefficients of correlation between the two were statistically highly significant suggesting that the prevalence of one varied directly with the prevalence of the other in the community, and that preve-lence of infection may be used as an indicator for the prevalence of disease at different points of time. The analysis also showed the existence of an inverse relationship between prevalence of tuber-culosis ane prevalence of non-specific sensitivity tending to confirm the previous finding that the latter offered protection against the other

जलवायु परिवर्तन और मानवीय गतिविधियों के प्रति क्रस्टेशियाई प्रजाति की सुभेद्यता

कृपया पूरा लेखा पढ

Seaweed resources of Kerala Coast

Surveys conducted for the first time recently along the Karala coast have indicated the presence of seaweeds at the following locations: Mullur,Vizhinjam, Kovalam , Chilakaar,Varkala, Edava, Tankasseri, Thirumullavaram, Kovilthottam, Cherai, Azhikkal, Perumpally, Thekkodu, Pallithodu, Chellanam, Kandakadavu, Elathur, Kadalur (Nandi) Madapalli, Tharayi, Tellicherry, Pallikere and Kanutheertha

Studies on the fauna associated with the cultured seaweed Gracilaria edulis

With a view to study the fauna associated with the cultured seaweed Gracilaria edulis in coastal waters of the Palk Bay and the Gulf of Mannar and to assess the damage, if any, caused by any of the organisms, samples of all animal associated with the cultured seaweeds were collected from the seaweed culture sites. Qualitative analysis of the samples indicated that the fauna is mainly composed of crabs, amphipods, polychaetes, isopods, copepods, gastropods, bivalves, holothurians and fishes. Quantitatively, crabs were found to be more numerous than all other groups, followed by amphipods and polychaetes