University of California, Irvine

About: University of California, Irvine is a education organization based out in Irvine, California, United States. It is known for research contribution in the topics: Population & Galaxy. The organization has 47031 authors who have published 113602 publications receiving 5521832 citations. The organization is also known as: UC Irvine & UCI.

Ice-Shelf Melting Around Antarctica

Abstract: We compare the volume flux divergence of Antarctic ice shelves in 2007 and 2008 with 1979 to 2010 surface accumulation and 2003 to 2008 thinning to determine their rates of melting and mass balance. Basal melt of 1325 ± 235 gigatons per year (Gt/year) exceeds a calving flux of 1089 ± 139 Gt/year, making ice-shelf melting the largest ablation process in Antarctica. The giant cold-cavity Ross, Filchner, and Ronne ice shelves covering two-thirds of the total ice-shelf area account for only 15% of net melting. Half of the meltwater comes from 10 small, warm-cavity Southeast Pacific ice shelves occupying 8% of the area. A similar high melt/area ratio is found for six East Antarctic ice shelves, implying undocumented strong ocean thermal forcing on their deep grounding lines.

Tracing Galaxy Formation with Stellar Halos. I. Methods

Abstract: If the favored hierarchical cosmological model is correct, then the Milky Way system should have accreted � 100– 200 luminous satellite galaxies in the past � 12 Gyr. We model this process using a hybrid semianalytic plus N-body approach that distinguishes explicitly between the evolution of light and dark matter in accreted satellites. This distinction is essential to our ability to produce a realistic stellar halo, with mass and density profile much like that of our own Galaxy, and a surviving satellite population that matches the observed number counts and structural parameter distributions of the satellite galaxies of the Milky Way. Our accreted stellar halos have density profiles that typically drop off with radius faster than the dark matter and follow power laws at rk30 kpc with � / r � � , � ’ 3 4. They are well fit by Hernquist profiles over the full radial range. We find that stellar halos are assembled from the inside out, with the majority of mass (� 80%) coming from the � 15 most massive accretion events. The satellites that contributetothestellarhalohavemedianaccretiontimes of � 9Gyrinthepast,whilesurvivingsatellitesystems have median accretion times of � 5 Gyr in the past. This implies that stars associated with the inner halo should be quite differentchemicallyfromstarsinsurvivingsatellitesandalsofromstarsintheouterhaloorthoseliberatedinrecent disruptionevents.Webrieflydiscusstheexpectedspatialstructureandphase-spacestructureforhalosformedinthismanner. Searches for this type of structure offer a direct test of whether cosmology is indeed hierarchical on small scales. Subject headingg dark matter — galaxies: dwarf — galaxies: evolution — galaxies: formation — galaxies: halos — galaxies: kinematics and dynamics — Galaxy: evolution — Galaxy: formation — Galaxy: halo — Galaxy: kinematics and dynamics — Local Group

The Biochemistry of Memory: A New and Specific Hypothesis.

Abstract: Recent studies have uncovered a synaptic process with properties required for an intermediate step in memory storage. Calcium rapidly and irreversibly increases the number of receptors for glutamate (a probable neurotransmitter) in forebrain synaptic membranes by activating a proteinase (calpain) that degrades fodrin, a spectrin-like protein. This process provides a means through which physiological activity could produce long-lasting changes in synaptic chemistry and ultrastructure. Since the process is only poorly represented in the brain stem, it is hypothesized to be responsible for those forms of memory localized in the telencephalon.

The ADP/ATP translocator is not essential for the mitochondrial permeability transition pore

Abstract: A sudden increase in permeability of the inner mitochondrial membrane, the so-called mitochondrial permeability transition, is a common feature of apoptosis and is mediated by the mitochondrial permeability transition pore (mtPTP). It is thought that the mtPTP is a protein complex formed by the voltage-dependent anion channel, members of the pro- and anti-apoptotic BAX-BCL2 protein family, cyclophilin D, and the adenine nucleotide (ADP/ATP) translocators (ANTs)1,2. The latter exchange mitochondrial ATP for cytosolic ADP and have been implicated in cell death. To investigate the role of the ANTs in the mtPTP, we genetically inactivated the two isoforms of ANT3,4,5 in mouse liver and analysed mtPTP activation in isolated mitochondria and the induction of cell death in hepatocytes. Mitochondria lacking ANT could still be induced to undergo permeability transition, resulting in release of cytochrome c. However, more Ca2+ than usual was required to activate the mtPTP, and the pore could no longer be regulated by ANT ligands. Moreover, hepatocytes without ANT remained competent to respond to various initiators of cell death. Therefore, ANTs are non-essential structural components of the mtPTP, although they do contribute to its regulation.

A call for transparent reporting to optimize the predictive value of preclinical research

Abstract: The US National Institute of Neurological Disorders and Stroke convened major stakeholders in June 2012 to discuss how to improve the methodological reporting of animal studies in grant applications and publications. The main workshop recommendation is that at a minimum studies should report on sample-size estimation, whether and how animals were randomized, whether investigators were blind to the treatment, and the handling of data. We recognize that achieving a meaningful improvement in the quality of reporting will require a concerted effort by investigators, reviewers, funding agencies and journal editors. Requiring better reporting of animal studies will raise awareness of the importance of rigorous study design to accelerate scientific progress.