LSST Science Book, Version 2.0

A survey that can cover the sky in optical bands over wide fields to faint magnitudes with a fast cadence will enable many of the exciting science opportunities of the next decade. The Large Synoptic Survey Telescope (LSST) will have an effective aperture of 6.7 meters and an imaging camera with field of view of 9.6 deg^2, and will be devoted to a ten-year imaging survey over 20,000 deg^2 south of +15 deg. Each pointing will be imaged 2000 times with fifteen second exposures in six broad bands from 0.35 to 1.1 microns, to a total point-source depth of r~27.5. The LSST Science Book describes the basic parameters of the LSST hardware, software, and observing plans. The book discusses educational and outreach opportunities, then goes on to describe a broad range of science that LSST will revolutionize: mapping the inner and outer Solar System, stellar populations in the Milky Way and nearby galaxies, the structure of the Milky Way disk and halo and other objects in the Local Volume, transient and variable objects both at low and high redshift, and the properties of normal and active galaxies at low and high redshift. It then turns to far-field cosmological topics, exploring properties of supernovae to z~1, strong and weak lensing, the large-scale distribution of galaxies and baryon oscillations, and how these different probes may be combined to constrain cosmological models and the physics of dark energy.Comment: 596 pages. Also available at full resolution at http://www.lsst.org/lsst/sciboo

Melatonin protects bovine embryos from heat stress and oxygen tension and improves embryo production in vitro

The objective of this study was to determine melatonin"s ameliorating effects against heat stress and oxygen tension in developing bovine embryos in vitro. The oocytes were collected from ovaries obtained from a local abattoir, followed by in vitro maturation, fertilization, and embryo culture. During in vitro culture, embryos were exposed to 5% (Group I) and 20% (Group II) oxygen tension with 10-3, 10-6, and 10-9 molar (M) melatonin, along with the control group without melatonin (Group III). Compared to the control group, melatonin at 10-6 and 10-9 concentrations increased in vitro development rates and decreased caspase 3/7 activity at 5% and 20% oxygen tension (P<0.01). Onehalf of the zygotes were cultured under normal temperature (38.5ºC) during the culture period, and the other half of the zygotes were heat stressed at 41ºC for six hours. Then they transferred into the normal culture conditions for the rest of the period using 0, 10- 6, and 10-9 M of melatonin (Group IV). Under normal temperature (38.5ºC), melatonin at 10-9 M was beneficial for in vitro development and DNA integrity. Under heat stress at 41ºC, melatonin at 10-6 and 10-9 M was useful for in vitro development and DNA integrity (P<0.05). Supplementation of melatonin to embryo culture medium did not alter the caspase 3 and 7 activities (P>0.05). In conclusion, melatonin prevents the adverse effects of heat stress and O2 tension on preimplantation bovine embryos in vitro

VideoPoet: A Large Language Model for Zero-Shot Video Generation

We present VideoPoet, a language model capable of synthesizing high-quality video, with matching audio, from a large variety of conditioning signals. VideoPoet employs a decoder-only transformer architecture that processes multimodal inputs -- including images, videos, text, and audio. The training protocol follows that of Large Language Models (LLMs), consisting of two stages: pretraining and task-specific adaptation. During pretraining, VideoPoet incorporates a mixture of multimodal generative objectives within an autoregressive Transformer framework. The pretrained LLM serves as a foundation that can be adapted for a range of video generation tasks. We present empirical results demonstrating the model's state-of-the-art capabilities in zero-shot video generation, specifically highlighting VideoPoet's ability to generate high-fidelity motions. Project page: http://sites.research.google/videopoet/Comment: To appear at ICML 2024; Project page: http://sites.research.google/videopoet

Direction Reconstruction using a CNN for GeV-Scale Neutrinos in IceCube

The IceCube Neutrino Observatory observes neutrinos interacting deep within the South Pole ice. It consists of 5,160 digital optical modules, which are embedded within a cubic kilometer of ice, over depths of 1,450 m to 2,450 m. At the lower center of the array is the DeepCore subdetector. Its denser sensor configuration lowers the observable energy threshold to the GeV-scale, facilitating the study of atmospheric neutrino oscillations. The precise reconstruction of neutrino direction is critical in the measurements of oscillation parameters. This work presents a method to reconstruct the zenith angle of GeV-scale events in IceCube by using a convolutional neural network and compares the result to that of the current likelihood-based reconstruction algorithm