Real-time lattice boltzmann shallow waters method for breaking wave simulations

We present a new approach for the simulation of surfacebased fluids based in a hybrid formulation of Lattice Boltzmann Method for Shallow Waters and particle systems. The modified LBM can handle arbitrary underlying terrain conditions and arbitrary fluid depth. It also introduces a novel method for tracking dry-wet regions and moving boundaries. Dynamic rigid bodies are also included in our simulations using a two-way coupling. Certain features of the simulation that the LBM can not handle because of its heightfield nature, as breaking waves, are detected and automatically turned into splash particles. Here we use a ballistic particle system, but our hybrid method can handle more complex systems as SPH. Both the LBM and particle systems are implemented in CUDA, although dynamic rigid bodies are simulated in CPU. We show the effectiveness of our method with various examples which achieve real-time on consumer-level hardware.Peer ReviewedPostprint (author's final draft

A multi-level spectral deferred correction method

The spectral deferred correction (SDC) method is an iterative scheme for computing a higher-order collocation solution to an ODE by performing a series of correction sweeps using a low-order timestepping method. This paper examines a variation of SDC for the temporal integration of PDEs called multi-level spectral deferred corrections (MLSDC), where sweeps are performed on a hierarchy of levels and an FAS correction term, as in nonlinear multigrid methods, couples solutions on different levels. Three different strategies to reduce the computational cost of correction sweeps on the coarser levels are examined: reducing the degrees of freedom, reducing the order of the spatial discretization, and reducing the accuracy when solving linear systems arising in implicit temporal integration. Several numerical examples demonstrate the effect of multi-level coarsening on the convergence and cost of SDC integration. In particular, MLSDC can provide significant savings in compute time compared to SDC for a three-dimensional problem

Comparison of various chiral stationary phases for the chromatographic separation of chiral pharmaceuticals

Many pharmaceuticals contain active ingredients that have more than one stereoisomer. An important concern is the recognition that these different stereoisomers do not necessarily have identical, or even desirable biological activity. Consequently, analytical methods for the analysis and separation of enantiomers are important in the proper development of a marketed pharmaceutical product. In this research, direct HPLC methods for the chromatographic separation of oxyphene optical isomers have been developed and optimized using three types of chiral stationary phases. The research carried out a systematic study of the conditions for the separation of oxyphene optical isomers using synthetic polymer chiral stationary phase of cellulose tris (3, 5-dimethylphenylcarbamate) Chiralcel OD, ß-cyclodextrin chiral stationary phase, and a1-acid glycoprotein chiral stationary phase. The methods using the ß-cyclodextrin and Chiralcel OD columns provide for the accurate determination of the optical purity (as low as 0.1%) of each enantiomer, in the presence of the other major enantiomer. The performance of these chiral stationary phases is also compared

Connecting Community and Family Philanthropy in Latin America: Mexico

This report explores the dynamics of community philanthropy and family philanthropy in Mexico in order to inform efforts to strengthen the connection between the two. In terms of community philanthropy, our primary focus is upon Mexico’s community foundation model, which is the most institutionalized form of community philanthropy and a uniquely important actor in the philanthropic ecosystem. Wealthy families and family businesses in Mexico are known to have strong local ties and to prioritize place-based development, and Mexico has more community foundations than any other Latin American country. In terms of family philanthropy, we have cast a wider net, interviewing families who work closely with community foundations, have their own private or company-linked foundations, or use a mix of organizational vehicles for their philanthropy. We also interviewed a handful of philanthropists who have not worked with community foundations, in order to get a sense of the full range of options

Patterns in the Tapestry: A Typology of Collective Giving Groups

The collective giving movement has seen remarkable growth across the U.S. in recent years, both in participation and impact. Between 2017 and 2023, nearly 4,000 collective giving groups engaged over 370,000 members, mobilizing $3.1 billion to support various causes (Loson-Ceballos & Layton, 2024, p. 1). These figures underscore the scale and scope of this dynamic movement. While all collective giving groups share a commitment to democratic processes for mobilizing and allocating resources for social impact, their structures, composition, and practices vary widely. By understanding and appreciating these differences, we can better grasp how collective giving is transforming philanthropy and driving social change. The purpose of this report is twofold. First, it presents a typology that serves as a framework to categorize collective giving groups. Second, it applies that framework to develop seven archetypes of collective giving groups

In Abundance An Analysis of the Thriving Landscape of Collective Giving in the U.S.

Philanthropy today faces many critical and complex challenges that are both uniquely urgent for our sector and grounded in wider forces beyond our control. Within this dynamic context, collective giving — a tradition observed across cultures worldwide and grounded in the ethos of community agency — has emerged as a growing force in U.S. philanthropy

Spatial control of Cdc42 signalling by a GM130-RasGRF complex regulates polarity and tumorigenesis

The small GTPase Cdc42 is a key regulator of polarity, but little is known in mammals about its spatial regulation and the relevance of spatial Cdc42 pools for polarity. Here we report the identification of a GM130-RasGRF complex as a regulator of Cdc42 at the Golgi. Silencing GM130 results in RasGRF-dependent inhibition of the Golgi pool of Cdc42, but does not affect Cdc42 at the cell surface. Furthermore, active Cdc42 at the Golgi is important to sustain asymmetric front-rear Cdc42-GTP distribution in directionally migrating cells. Concurrent to Cdc42 inhibition, silencing GM130 also results in RasGRF-dependent Ras-ERK pathway activation. Moreover, depletion of GM130 is sufficient to induce E-cadherin downregulation, indicative of a loss in cell polarity and epithelial identity. Accordingly, GM130 expression is frequently lost in colorectal and breast cancer patients. These findings establish a previously unrecognized role for a GM130-RasGRF-Cdc42 connection in regulating polarity and tumorigenesis

Selective Serotonin Reuptake Inhibitors and Gastrointestinal Bleeding: A Case-Control Study

BACKGROUND: Selective serotonin reuptake inhibitors (SSRIs) have been associated with upper gastrointestinal (GI) bleeding. Given their worldwide use, even small risks account for a large number of cases. This study has been conducted with carefully collected information to further investigate the relationship between SSRIs and upper GI bleeding. METHODS: We conducted a case-control study in hospitals in Spain and in Italy. Cases were patients aged ≥18 years with a primary diagnosis of acute upper GI bleeding diagnosed by endoscopy; three controls were matched by sex, age, date of admission (within 3 months) and hospital among patients who were admitted for elective surgery for non-painful disorders. Exposures to SSRIs, other antidepressants and other drugs were defined as any use of these drugs in the 7 days before the day on which upper gastrointestinal bleeding started (index day). RESULTS: 581 cases of upper GI bleeding and 1358 controls were considered eligible for the study; no differences in age or sex distribution were observed between cases and controls after matching. Overall, 4.0% of the cases and 3.3% of controls used an SSRI antidepressant in the week before the index day. No significant risk of upper GI bleeding was encountered for SSRI antidepressants (adjusted odds ratio, 1.06, 95% CI, 0.57-1.96) or for whichever other grouping of antidepressants. CONCLUSIONS: The results of this case-control study showed no significant increase in upper GI bleeding with SSRIs and provide good evidence that the magnitude of any increase in risk is not greater than 2

Salmonella-Induced Mucosal Lectin RegIIIβ Kills Competing Gut Microbiota

Intestinal inflammation induces alterations of the gut microbiota and promotes overgrowth of the enteric pathogen Salmonella enterica by largely unknown mechanisms. Here, we identified a host factor involved in this process. Specifically, the C-type lectin RegIIIβ is strongly upregulated during mucosal infection and released into the gut lumen. In vitro, RegIIIβ kills diverse commensal gut bacteria but not Salmonella enterica subspecies I serovar Typhimurium (S. Typhimurium). Protection of the pathogen was attributable to its specific cell envelope structure. Co-infection experiments with an avirulent S. Typhimurium mutant and a RegIIIβ-sensitive commensal E. coli strain demonstrated that feeding of RegIIIβ was sufficient for suppressing commensals in the absence of all other changes inflicted by mucosal disease. These data suggest that RegIIIβ production by the host can promote S. Typhimurium infection by eliminating inhibitory gut microbiota