Hydraulic Computations for Stepped Concrete Overlays of Embankment Dams

One method for rehabilitating and modernizing embankment dams is the addition of a concrete overlay that protects the embankment and allows floods to pass safely over the dam. Roller compacted concrete is commonly used, which makes it practical to use a stepped construction that also enhances energy dissipation. Analysis of flow conditions over such structures requires computation of aerated flow and its effects on flow depth, training wall design, and energy dissipation. This paper describes Spillway Pro, an energy-based water surface profile calculation tool for smooth spillway chutes (Wahl et al. 2019), recently improved to also analyze stepped chutes. The tool is applicable to a wide range of chute slopes, including flatter slopes typical of embankment dam overlays and steeper slopes encountered on concrete gravity dams. An energy-based analysis allows Spillway Pro to be applied to situations differing from the idealized configurations covered by available empirical approaches, such as non-constant slopes, varying step heights, and converging chutes. Spillway Pro integrates water surface profile calculations, aerated flow effects, and cavitation analysis, which is potentially important for steeper slopes and large unit discharges. Simultaneous calculation of smooth and stepped-chute flow profiles enables rapid assessment of the energy dissipation benefits of steps, as well as a comparison of the aerated flow and cavitation issues for smooth vs. stepped chute alternatives

Microstructural and Rheological Transitions in Bacterial Biofilms

Abstract Biofilms are aggregated bacterial communities structured within an extracellular matrix (ECM). ECM controls biofilm architecture and confers mechanical resistance against shear forces. From a physical perspective, biofilms can be described as colloidal gels, where bacterial cells are analogous to colloidal particles distributed in the polymeric ECM. However, the influence of the ECM in altering the cellular packing fraction (ϕ) and the resulting viscoelastic behavior of biofilm remains unexplored. Using biofilms of Pantoea sp. (WT) and its mutant (ΔUDP), the correlation between biofilm structure and its viscoelastic response is investigated. Experiments show that the reduction of exopolysaccharide production in ΔUDP biofilms corresponds with a seven‐fold increase in ϕ, resulting in a colloidal glass‐like structure. Consequently, the rheological signatures become altered, with the WT behaving like a weak gel, whilst the ΔUDP displayed a glass‐like rheological signature. By co‐culturing the two strains, biofilm ϕ is modulated which allows us to explore the structural changes and capture a change in viscoelastic response from a weak to a strong gel, and to a colloidal glass‐like state. The results reveal the role of exopolysaccharide in mediating a structural transition in biofilms and demonstrate a correlation between biofilm structure and viscoelastic response

Firms' Main Market, Human Capital and Wages

Recent international trade literature emphasizes two features in characterizing the current patterns of trade: efficiency heterogeneity at the firm level and quality differentiation. This paper explores human capital and wage differences across firms in that context. We build a partial equilibrium model predicting that firms selling in more-remote markets employ higher human capital and pay higher wages to employees within each education group. The channel linking these variables is firms’ endogenous choice of quality. Predictions are tested using Spanish employer-employee matched data that classify firms according to four main destination markets: local, national, European Union, and rest of the World. Employees’ average education is increasing in the remoteness of firm’s main output market. Market–destination wage premia are large, increasing in the remoteness of the market, and increasing in individual education. These results suggest that increasing globalization may play a significant role in raising wage inequality within and across education groups

Stochastic Assembly of Bacteria in Microwell Arrays Reveals the Importance of Confinement in Community Development

Citation: Hansen, R. H., Timm, A. C., Timm, C. M., Bible, A. N., Morrell-Falvey, J. L., Pelletier, D. A., . . . Retterer, S. T. (2016). Stochastic Assembly of Bacteria in Microwell Arrays Reveals the Importance of Confinement in Community Development. Plos One, 11(5), 18. doi:10.1371/journal.pone.0155080The structure and function of microbial communities is deeply influenced by the physical and chemical architecture of the local microenvironment and the abundance of its community members. The complexity of this natural parameter space has made characterization of the key drivers of community development difficult. In order to facilitate these characterizations, we have developed a microwell platform designed to screen microbial growth and interactions across a wide variety of physical and initial conditions. Assembly of microbial communities into microwells was achieved using a novel biofabrication method that exploits well feature sizes for control of innoculum levels. Wells with incrementally smaller size features created populations with increasingly larger variations in inoculum levels. This allowed for reproducible growth measurement in large (20 mu m diameter) wells, and screening for favorable growth conditions in small (5, 10 mu m diameter) wells. We demonstrate the utility of this approach for screening and discovery using 5 mu m wells to assemble P. aeruginosa colonies across a broad distribution of innoculum levels, and identify those conditions that promote the highest probability of survivial and growth under spatial confinement. Multi-member community assembly was also characterized to demonstrate the broad potential of this platform for studying the role of member abundance on microbial competition, mutualism and community succession

A prospective metagenomic and metabolomic analysis of the impact of exercise and/or whey protein supplementation on the gut microbiome of sedentary adults

Many components of modern living exert influence on the resident intestinal microbiota of humans with resultant impact on host health. For example, exercise-associated changes in the diversity, composition, and functional profiles of microbial populations in the gut have been described in cross-sectional studies of habitual athletes. However, this relationship is also affected by changes in diet, such as changes in dietary and supplementary protein consumption, that coincide with exercise. To determine whether increasing physical activity and/or increased protein intake modulates gut microbial composition and function, we prospectively challenged healthy but sedentary adults with a short-term exercise regime, with and without concurrent daily whey protein consumption. Metagenomics- and metabolomics-based assessments demonstrated modest changes in gut microbial composition and function following increases in physical activity. Significant changes in the diversity of the gut virome were evident in participants receiving daily whey protein supplementation. Results indicate that improved body composition with exercise is not dependent on major changes in the diversity of microbial populations in the gut. The diverse microbial characteristics previously observed in long-term habitual athletes may be a later response to exercise and fitness improvement. IMPORTANCE The gut microbiota of humans is a critical component of functional development and subsequent health. It is important to understand the lifestyle and dietary factors that affect the gut microbiome and what impact these factors may have. Animal studies suggest that exercise can directly affect the gut microbiota, and elite athletes demonstrate unique beneficial and diverse gut microbiome characteristics. These characteristics are associated with levels of protein consumption and levels of physical activity. The results of this study show that increasing the fitness levels of physically inactive humans leads to modest but detectable changes in gut microbiota characteristics. For the first time, we show that regular whey protein intake leads to significant alterations to the composition of the gut virome

Rift structure and sediment infill of hyperextended continental crust: insights from 3D seismic and well data (Xisha Trough, South China Sea)

Three‐dimensional seismic and well data from the deepwater Xisha Trough are used to investigate the rift structure and sediment infill of a region formed adjacently to the initial oceanic ridge of the South China Sea (SCS). The high‐quality data permitted a detailed analysis of features such as: (1) detachment faults soling out at the Moho, (2) rotated and thinned continental blocks covered by thick sediment, and (3) changes in the location of basin depocenters resulting from detachment faulting. During the continental rifting phase (Eocene to earliest Oligocene), faulting was broadly distributed in Xisha Trough and resulted in the generation of isolated grabens/half‐grabens filled by proximal sediment sources. During continental breakup in the Northwest Ocean Sector of SCS (Oligocene), extension became restricted to a narrow region where highly tilted continental blocks and thin crust were formed. Sediment was, at that time, fed to distal depocenters, which are presently bounded by listric faults rooted in a basal detachment. Later in a second stage (early Miocene), synchronously with continental breakup in the Southwest Ocean Sector of the SCS, the study area was blanketed by thick sediment. During the two continental breakup events, the hyperextended Xisha Trough was affected by closely spaced, small‐scale faults rather than large basement‐related structures. Our study highlights the effect of continental breakup as a way to broaden sediment influx from multiple sources into deepwater basins. As a corollary, this work recognizes two distinct breakup sequences in the Xisha Trough, and concludes on their geodynamic significance to the SCS

TRIPS implementation and secondary pharmaceutical patenting in Brazil and India

This article compares national approaches toward secondary pharmaceutical patents. Because secondary patents can extend periods of exclusivity and delay generic competition, they can raise prices and reduce access to medicines. Little is known about what measures countries have enacted policies to address applications for secondary pharmaceutical patents, how they function, and whether, in practice, these measures limit secondary patents. We analyze the cases of India and Brazil. We assemble data on pharmaceutical patent applications filed in the two countries, code each application to identify which constitute secondary applications, and examine outcomes for each application in both countries. The data indicate that Brazil is less likely to grant applications than India, but in both countries the measures designed to limit secondary patents are having little direct effect. This suggests, on the one hand, that critics of these policies, such as the transnational pharmaceutical sector and foreign governments, may be more worried than they should be. On the other hand, champions of the policies, such as NGOs and international organizations, may have cause for concern that laws on the books are not having the expected impact on patent outcomes in practice. Our findings also suggest that, at the drug level, the effects of countries’ approaches toward secondary patents need to be understood in the context of their broader approaches toward TRIPS implementation, including when and how they introduced pharmaceutical patents in the 1990s and 2000s

Physiological adaptations in ultra‐endurance athletes during a 5‐day multisport adventure race: an assessment of serological and inflammatory cytokine profiles

Multiday endurance sports expose athletes to multiple physical stressors. Little is known about the athletes’ physiological responses to these stressors. A detailed understanding of the serological changes that occur during competition may improve the treatment of athletes suffering from illness or injury. This prospective, observational study aimed to characterize serological changes in AR athletes across multiday competition. Athletes underwent venipuncture at the start, midpoint, and end of a 5‐day, multidiscipline event. A variety of serological and inflammatory factors was measured and then analyzed to describe their changes over the course of the race. A total of 27 AR athletes (29.6% female, 70.4% male) met inclusion criteria out of 33 recruited initially. The mean age was 37.7 (IQR 32.5, 41). The median race time for athletes was 133 hours (IQR 123, 142). Serum creatinine, sodium, and potassium tended to remain stable as the race progressed. Conversely, serological measures, including hemoglobin, interleukin‐6, and C‐reactive protein levels, tended to change substantially during the race. Participants demonstrated the ability to maintain homeostasis, despite significant physiological threat. Renal function, electrolyte balance, and hormonal profiles were stable. However, a pro‐inflammatory response and decrease in red cell availability were evident by the midpoint of the race