Computer-based library or computer-based learning?

Traditionally, libraries have played the role of repository of published information resources and, more recently, gateway to online subscription databases. The library online catalog and digital library interface serve an intermediary function to help users locate information resources available through the library. With competition from Web search engines and Web portals of various kinds available for free, the library has to step up to play a more active role as guide and coach to help users make use of information resources for learning or to accomplish particular tasks. It is no longer sufficient for computer-based library systems to provide just search and access functions. They must provide the functionality and environment to support learning and become computer-based learning systems. This paper examines the kind of learning support that can be incorporated in library online catalogs and digital libraries, including 1) enhanced support for information browsing and synthesis through linking by shared meta-data, references and concepts; 2) visualization of related information; 3) adoption of Library 2.0 and social technologies; 4) adoption of Library 3.0 technologies including intelligent processing and text mining

Variations in carambola infestation rates byBactrocera carambolae drew and hancock (Diptera: Tephritidae) with fruit availability in a carambola orchard

The relationship between the infestation rate of carambola fruits by Bactrocera caram­bolae Drew and Hancock was investigated in a carambola orchard. Phenology of the fruits was found to influence percentage infestation of fruits by B. carambolae. The proportion of unbagged or susceptible fruits infested varied with time of year and tended to decrease with the increase of unbagg­ed fruits available on the tree. The number of ovipunctures per fruit varied with fruit size and was also found to be indicative of the number of adult insects (B. carambolae and parasitoids) that will emerge from each fruit. Higher number of susceptible fruits available on each tree also decreased both the number of ovipunctures per fruit and the number of eggs laid per fruit, which could possibly be due to the strategy of spreading the risk adopted by the female B. carambolae or a result of random selection with more hosts available. The main parasitoids recorded were Biosteres vandenboschi (Fullaway) and B. arisanus (Sonan). The mean percentage of parasitism was 38.3% and it followed roughly that of infestation of fruits

Rotation-aligned isomer and oblate collectivity in Pt 196

An oblate rotational sequence, built on an aligned, two-quasineutron isomeric state has been established in Pt196. The isomer has a half-life of 7.7(7) ns and is associated with the Iπ=12+,(i13/2)2 neutron configuration. Excited states, with angular momentum generated primarily through successive nucleon alignments, have been populated through 1p transfer from Au197. The nucleus Pt196 is the most neutron-rich Pt isotope for which high-spin states, beyond the 12+ isomeric state, have been established thus far. Cranked shell model calculations have been performed to understand shape evolution with spin, and the role of nucleons occupying specific Nilsson orbitals in generating aligned angular momentum for both prolate and oblate deformations has been explored

Isomers and oblate rotation in Pt isotopes: Delineating the limit for collectivity at high spins

Rotation-aligned isomeric states and associated oblate collective sequences are established in even Pt isotopes. Reduced E2 transition probabilities for the deexcitation of the 12+ isomers indicate an abrupt and unexpected quenching of oblate collectivity around neutron number N=120. Structure and shape evolution at high spin in the heaviest stable isotopes is found to be markedly different from observations in the lighter ones

Structure of odd- A Pt isotopes along the line of stability

The structure of the odd-A isotopes Pt193,195,197, which lie along the line of stability, has been studied up to high spin through multinucleon transfer reactions. Positive- and negative-parity sequences in Pt193,195 have been considerably extended and multiple band crossings established. An isomer with T1/2=5.0(5) ns and Iπ=25/2- is present in Pt195. The isotopes Pt193,195 are characterized by moderate oblate deformation, and angular momentum generation at high spin in the yrast, positive-parity sequences is attributed to the rotation alignment of i13/2 neutrons and h11/2 protons. A detailed understanding of the observed features is presented using calculations based on tilted axis cranking covariant density functional theory as well as others with the ultimate cranker code

Multiple octupole-type band structures in Th220: Reflection-asymmetric tidal waves?

The Th220 level scheme has been considerably extended from an experiment using the Mg26+Pt198 reaction at 128 MeV. The evaporation residues from this very fissile system were selected with the HERCULES detector system and residue-gated γ rays were measured with Gammasphere. The simplex feature (alternating-parity levels) persists up to the highest spins observed (23), but the nucleus exhibits a more vibrational-like behavior than the heavier Th isotopes. In addition, a doubling of the negative-parity, odd-spin states is seen as well as a staggering of the B(E1)/B(E2) ratios. A new interpretation based on a picture of tidal waves on a reflection-asymmetric nuclear surface is proposed

Parity doubling in Th219 and the onset of collectivity above N=126

Excited states in Th219 have been observed for the first time in an experiment using the Mg26+Pt198 reaction and evaporation-residue-gated γ-ray spectroscopy. Two structures of interlinked alternating-parity levels with simplex quantum numbers s=±i are observed, reminiscent of similar sequences in heavier odd-mass isotopes, but only three mass units away from the N=126 neutron closed shell. The emergence of quadrupole-octupole collectivity in this mass region and the trend for parity-doublet bands are discussed

Nanosecond isomers and the evolution of collectivity in stable, even-A Hg isotopes

Isomeric states and associated collective structures have been studied up to high spin in Hg198,200,202 using multinucleon transfer reactions and the Gammasphere array. A coupled rotational band, with possible four-quasiparticle character, is established in Hg198. Sequences built on two-quasiparticle, positive-and negative-parity levels are assigned to Hg202. New isomers in Hg202 with Iπ=(7-) and (9-), and T1/2 = 10.4(4) ns and 1.4(3) ns, respectively, have been identified. A half-life of 1.0(3) ns is established for the Iπ=12+ state in Hg200. B(E2) values deduced from isomeric transitions in Hg isotopes indicate that, while collectivity near the ground state gradually diminishes from N = 112 to N = 124, it is found to increase for the 12+ and 9-states up to N = 118, followed by a reduction for higher neutron numbers. Calculations using the ultimate cranker code provide insight into the variation of deformation with spin and allow for an understanding of observed band crossings. The evolution of collectivity with spin, and along the isotopic chain, is described