A differential-geometric approach to deformations of pairs (X,E)(X,E)

This article gives an exposition of the deformation theory for pairs $(X, E)$, where $X$ is a compact complex manifold and $E$ is a holomorphic vector bundle over $X$, adapting an analytic viewpoint \`{a} la Kodaira-Spencer. By introducing and exploiting an auxiliary differential operator, we derive the Maurer--Cartan equation and differential graded Lie algebra (DGLA) governing the deformation problem, and express them in terms of differential-geometric notions such as the connection and curvature of $E$, obtaining a chain level refinement of the classical results that the tangent space and obstruction space of the moduli problem are respectively given by the first and second cohomology groups of the Atiyah extension of $E$ over $X$. As an application, we give examples where deformations of pairs are unobstructed.Comment: 28 pages; v4: title changed, to appear in Complex Manifold

Geometric quantization via SYZ transforms

The so-called quantization problem in geometric quantization is asking whether the space of wave functions is independent of the choice of polarization. In this paper, we apply SYZ transforms to solve the quantization problem in two cases: (1) semi-flat Lagrangian torus fibrations over complete compact integral affine manifolds, and (2) projective toric manifolds. More precisely, we prove that the space of wave functions associated to the real polarization is canonically isomorphic to that associated to a complex polarization via SYZ transforms in both cases.Comment: Final versio

Climate change impacts on O3, NOx, OH and HO2 in Malaysia

The Earth's atmosphere is an oxidizing blanket with ozone and hydroxyl radical as the principal oxidants which could be affected by climate change where climate change may change the chemical composition of the species. How much the climate change affects these oxidants in the tropical region especially in Malaysia is relatively unknown. This study was explore in order to enhance the understanding of this issue by achieving the objectives: (a) to simulate climate changes using regional climate modeling system PRECIS (Providing Regional Climates for Impacts Studies) under SRES (Special Report on Emissions Scenarios) B2 and A2 emission scenarios of the Intergovernmental Panel on Climate Change (IPCC) for the Malaysian domain; (b) to investigate the impact of climate change to the air quality and atmospheric oxidizing capacity under both emission scenarios using chemistry model CiTTyCAT (Cambridge Tropospheric Trajectory model of Chemistry and Transport). In both scenariOS, surface temperatures in the future were found to increases during the both seasons in Malaysia, wet season (December, January, February) and dry season (June, July, August) by 2 DC and 3 DC respectively. For precipitation rate under B2 scenario, it decreases by -0.56 mm day-l during wet season but increases by 0.34 mm day-l during dry season. Meanwhile under A2 scenario the precipitation rate increases during the both seasons. In response to the climate change, 0 3 concentration in remote (Danum) and rural (Kapit) area showed a high decrease in percentage of about 20 to 50 % but relatively lower in sub urban (Sg. Petani) area with only 2 to 5 % and showed variability changes in urban areas (Kota Kinabalu, Kuala Lumpur and Pasir Gudang). Under the same climate scenariOS, the oxidizing capacity in term of OH concentrations was decreased in remote and rural areas about 20 to 50 % of changes. Meanwhile the increases in sub urban area of about 2 to 15 % changes were observed. High variability of changes was observed in the urban areas. In the next century, changes of the climate in Malaysia will affect the air quality and oxidizing capacity of the atmosphere. Thus, it is important to assess the extent of vulnerability and risk of climate to the air quality in the region to improve the mitigative and adaptive capacity policy and strategy

Wave-packet treatment of neutrino oscillations and its implications on determining the neutrino mass hierarchy

We derive the neutrino flavor transition probabilities with the neutrino treated as a wave packet. The decoherence and dispersion effects from the wave-packet treatment show up as damping and phase-shifting of the plane-wave neutrino oscillation patterns. If the energy uncertainty in the initial neutrino wave packet is larger than around 0.01 of the neutrino energy, the decoherence and dispersion effects would degrade the sensitivity of reactor neutrino experiments to mass hierarchy measurement to lower than 3 $\sigma$ confidence level

Turn-by-Turn Imaging of the Transverse Beam Profile in PEP-II

During injection or instability, the transverse profile of an individual bunch in a storage ring can change significantly in a few turns. However, most synchrotron-light imaging techniques are not designed for this time scale. We have developed a novel diagnostic that enhances the utility of a fast gated camera by adding, inexpensively, some features of a dual-axis streak camera, in order to watch the turn-by-turn evolution of the transverse profile, in both x and y. The beam's elliptical profile is reshaped using cylindrical lenses to form a tall and narrow ellipse—essentially the projection of the full ellipse onto one transverse axis. We do this projection twice, by splitting the beam into two paths at different heights, and rotating the ellipse by 90° on one path. A rapidly rotating mirror scans these vertical “pencils” of light horizontally across the photocathode of the camera, which is gated for 3 ns on every Nth ring turn. A single readout of the camera captures 100 images, looking like a stroboscopic photograph of a moving object. We have observed the capture of injected charge into a bunch and the rapid change of beam size at the onset of a fast instability