UC Santa Cruz

Abstract: The ATLAS Google Project was established as part of an ongoing evaluation of the use of commercial clouds by the ATLAS Collaboration, in anticipation of the potential future adoption of such resources by WLCG grid sites to fulfil or complement their computing pledges. Seamless integration of Google cloud resources into the worldwide ATLAS distributed computing infrastructure was achieved at large scale and for an extended period of time, and hence cloud resources are shown to be an effective mechanism to provide additional, flexible computing capacity to ATLAS. For the first time a total cost of ownership analysis has been performed, to identify the dominant cost drivers and explore effective mechanisms for cost control. Network usage significantly impacts the costs of certain ATLAS workflows, underscoring the importance of implementing such mechanisms. Resource bursting has been successfully demonstrated, whilst exposing the true cost of this type of activity. A follow-up to the project is underway to investigate methods for improving the integration of cloud resources in data-intensive distributed computing environments and reducing costs related to network connectivity, which represents the primary expense when extensively utilising cloud resources.

The author witnessed the Chilean coup d'etat in 1973. Years later he finds José Emilio Pacheco's, the Mexican bard, report on the event.

Adolescents, especially female youth, who have more family meals tend to be at lower risk for substance use. The present study tested whether family meals relate to substance use count and frequency during high school, whether associations differ by gender, and whether other family-related variables explain these associations. A community sample of 316 adolescents (M _age = 16.40, SD = 0.74; 56.96% female; 41.77% Latine, 23.10% Asian American, 29.11% European American, 6.01% from other ethnic backgrounds including Middle Eastern and African American) reported the number of substances they have ever used and how often they used alcohol, marijuana, and cigarettes, and completed measures of parental support and family cohesion. Across 15 days, they reported whether they had a family meal, got along with parents, and spent leisure time with their family each day. Regression models tested associations between frequency of family meals and substance use, whether associations differed by gender, and whether associations were explained by other family-related variables. Results indicated that more frequent family meals were associated with lower substance use count and less frequent alcohol, marijuana, and cigarette use among female adolescents but not male adolescents. Other daily family experiences were unrelated to substance use, and family meal frequency was independently related to lower substance use after accounting for parental support and family cohesion. Taken together, more frequent family meals in high school may reduce substance use risk for female adolescents, and interventions could consider promoting family meals in addition to other positive family values.

Dinitrogen (N2) fixation supports marine life through the supply of reactive nitrogen. Recent studies suggest that particle-associated non-cyanobacterial diazotrophs (NCDs) could contribute significantly to N2 fixation contrary to the paradigm of diazotrophy as primarily driven by cyanobacterial genera. We examine the community composition of NCDs associated with suspended, slow, and fast-sinking particles in the North Pacific Subtropical Gyre. Suspended and slow-sinking particles showed a higher abundance of cyanobacterial diazotrophs than fast-sinking particles, while fast-sinking particles showed a higher diversity of NCDs including Marinobacter, Oceanobacter and Pseudomonas. Using single-cell mass spectrometry we find that Gammaproteobacteria N2 fixation rates were higher on suspended and slow-sinking particles (up to 67 ± 48.54 fmol N cell⁻¹ d⁻¹), while putative NCDs rates were highest on fast-sinking particles (121 ± 22.02 fmol N cell⁻¹ d⁻¹). These rates are comparable to previous diazotrophic cyanobacteria observations, suggesting that particle-associated NCDs may be important contributors to pelagic N2 fixation.

Meiotic crossover recombination is essential for both accurate chromosome segregation and the generation of new haplotypes for natural selection to act upon. This requirement is known as crossover assurance and is one example of crossover control. While the conserved role of the ATPase, PCH-2, during meiotic prophase has been enigmatic, a universal phenotype when pch-2 or its orthologs are mutated is a change in the number and distribution of meiotic crossovers. Here, we show that PCH-2 controls the number and distribution of crossovers by antagonizing their formation. This antagonism produces different effects at different stages of meiotic prophase: early in meiotic prophase, PCH-2 prevents double-strand breaks from becoming crossover-eligible intermediates, limiting crossover formation at sites of initial double-strand break formation and homolog interactions. Later in meiotic prophase, PCH-2 winnows the number of crossover-eligible intermediates, contributing to the designation of crossovers and ultimately, crossover assurance. We also demonstrate that PCH-2 accomplishes this regulation through the meiotic HORMAD, HIM-3. Our data strongly support a model in which PCH-2s conserved role is to remodel meiotic HORMADs throughout meiotic prophase to destabilize crossover-eligible precursors and coordinate meiotic recombination with synapsis, ensuring the progressive implementation of meiotic recombination and explaining its function in the pachytene checkpoint and crossover control.