Numerical simulation of cavitation and atomization using a fully compressible three-phase model

The aim of this paper is to present a fully compressible three-phase (liquid, vapour and air) model and its application to the simulation of in-nozzle cavitation effects on liquid atomization. The model employs a combination of homogeneous equilibrium barotropic cavitation model with an implicit sharp interface capturing VoF approximation. The numerical predictions are validated against the experimental results obtained for injection of water into the air from a step-nozzle, which is designed to produce asymmetric cavitation along its two sides. Simulations are performed for three injection pressures, corresponding to three different cavitation regimes, referred to as cavitation inception, developing cavitation and hydraulic-flip. Model validation is achieved by qualitative comparison of the cavitation, spray pattern and spray cone angles. The flow turbulence in this study is resolved using the Large Eddy Simulation approach. The simulation results indicate that the major parameters that influence the primary atomization are cavitation, liquid turbulence and, to a smaller extent, the Rayleigh-Taylor and Kelvin-Helmholtz aerodynamic instabilities developing on the liquid/air interface. Moreover, the simulations performed indicate that periodic entrainment of air into the nozzle occurs at intermediate cavitation numbers, corresponding to developing cavitation (as opposed to incipient and fully-developed cavitation regimes); this transient effect causes a periodic shedding of the cavitation and air clouds and contributes to improved primary atomization. Finally, the cone angle of the spray is found to increase with increased injection pressure but drops drastically when hydraulic-flip occurs, in agreement with the relevant experiments

Agroecology and climate change rapid evidence review: Performance of agroecological approaches in low- and middle- income countries

Agroecology is increasingly seen as being able, or even necessary, to transform food systems (HLPE 2019). The Foreign, Commonwealth and Development Office (FCDO) and the CGIAR Research Programme on Climate Change, Agriculture and Food Security (CCAFS) commissioned this rapid evidence-based review to assess the quality and strength of evidence regarding (i) the impact of agroecological approaches on climate change mitigation and adaptation in low- and middle-income countries (LMICs) and (ii) the programming approaches and conditions supporting large-scale transitions to agroecology and transitions. The review also aims to identify knowledge gaps critical to understand and inform future public and private investment in research, development, and deployment of agroecological approaches. The focus here is on the science of agroecology at the field and landscape level, not on social movement, value chain or business aspects. We use the Food and Agriculture Organization of the United Nations (FAO) 10 elements of agroecology with the Gliessman (2016) framework to identify agroecology practices (transition level 2) and agroecology systems (transition level 3). To assess evidence related to agroecology‘s climate change outcomes we conducted a systematic literature review of i) synthesis papers and ii) primary empirical studies related to nutrient and pest and disease management. For the latter we documented the presence of evidence for climate change outcome indicators, but not the magnitude or direction of the change. We also conducted semi-structured interviews with representatives from 12 organizations supporting or implementing on-the-ground agricultural development programmes to better understand the feasibility of scaling out agroecology

Surveillance after initial surgery for pediatric and adolescent girls with stage I ovarian germ cell tumors: report from the Children's Oncology Group

PURPOSE: To determine whether overall survival (OS) can be preserved for patients with stage I pediatric malignant ovarian germ cell tumor (MOGCT) with an initial strategy of surveillance after surgical resection. PATIENTS AND METHODS: Between November 2003 and July 2011, girls age 0 to 16 years with stage I MOGCT were enrolled onto Children's Oncology Group study AGCT0132. Required histology included yolk sac, embryonal carcinoma, or choriocarcinoma. Surveillance included measurement of serum tumor markers and radiologic imaging at defined intervals. In those with residual or recurrent disease, chemotherapy with compressed PEB (cisplatin, etoposide, and bleomycin) was initiated every 3 weeks for three cycles (cisplatin 33 mg/m(2) on days 1 to 3, etoposide 167 mg/m(2) on days 1 to 3, bleomycin 15 U/m(2) on day 1). Survivor functions for event-free survival (EFS) and OS were estimated using the Kaplan-Meier method. RESULTS: Twenty-five girls (median age, 12 years) with stage I MOGCT were enrolled onto AGCT0132. Twenty-three patients had elevated alpha-fetoprotein (AFP) at diagnosis. Predominant histology was yolk sac. After a median follow-up of 42 months, 12 patients had evidence of persistent or recurrent disease (4-year EFS, 52%; 95% CI, 31% to 69%). Median time to recurrence was 2 months. All patients had elevated AFP at recurrence; six had localized disease, two had metastatic disease, and four had tumor marker elevation only. Eleven of 12 patients experiencing relapse received successful salvage chemotherapy (4-year OS, 96%; 95% CI, 74% to 99%). CONCLUSION: Fifty percent of patients with stage I pediatric MOGCT can be spared chemotherapy; treatment for those who experience recurrence preserves OS. Further study is needed to identify the factors that predict recurrence and whether this strategy can be extended successfully to older adolescents and young adults

Bulletin No. 9: Six points of Especial Botanical Interest in Connecticut

The areas described are the Barn Island Marshes, the Connecticut Arboretum, the North Haven Sand Plains, Catlin Wood, Cathedral Pines and the Bigelow Pond Hemlocks. 32 pp

Treatment options for subjective tinnitus: Self reports from a sample of general practitioners and ENT physicians within Europe and the USA

<p>Abstract</p> <p>Background</p> <p>Tinnitus affects about 10-15% of the general population and risks for developing tinnitus are rising through increased exposure to leisure noise through listening to personal music players at high volume. The disorder has a considerable heterogeneity and so no single mechanism is likely to explain the presence of tinnitus in all those affected. As such there is no standardized management pathway nor singly effective treatment for the condition. Choice of clinical intervention is a multi-factorial decision based on many factors, including assessment of patient needs and the healthcare context. The present research surveyed clinicians working in six Westernized countries with the aims: a) to establish the range of referral pathways, b) to evaluate the typical treatment options for categories of subjective tinnitus defined as acute or chronic, and c) to seek clinical opinion about levels of satisfaction with current standards of practice.</p> <p>Methods</p> <p>A structured online questionnaire was conducted with 712 physicians who reported seeing at least one tinnitus patients in the previous three months. They were 370 general practitioners (GPs) and 365 ear-nose-throat specialists (ENTs) from the US, Germany, UK, France, Italy and Spain.</p> <p>Results</p> <p>Our international comparison of health systems for tinnitus revealed that although the characteristics of tinnitus appeared broadly similar across countries, the patient's experience of clinical services differed widely. GPs and ENTs were always involved in referral and management to some degree, but multi-disciplinary teams engaged either neurology (Germany, Italy and Spain) or audiology (UK and US) professionals. For acute subjective tinnitus, pharmacological prescriptions were common, while audiological and psychological approaches were more typical for chronic subjective tinnitus; with several specific treatment options being highly country specific. All therapy options were associated with low levels of satisfaction.</p> <p>Conclusions</p> <p>Despite a large variety of treatment options, the low success rates of tinnitus therapy lead to frustration of physicians and patients alike. For subjective tinnitus in particular, effective therapeutic options with guidelines about key diagnostic criteria are urgently needed.</p

On the Peripheries of Planetary Urbanization: Globalizing Manaus and its Expanding Impact

In this paper I argue that global urbanism produces peripherality in ways that cannot be adequately problematized without taking into account its actual extent and geographically uneven development. Therefore, planetary urbanization needs to engage scholarly traditions attuned to regional urbanization if the discourse is to move past limitations in the urban globalization canon and its narrow focus on cities. To that end, I examine research on extensive urbanization in the Amazon region. Illustrative case studies show how attempts to globalize Manaus precipitated territorial restructuring and sociospatial change far beyond the city's boundaries. Manaus is now a more unequal city. Selective metropolitan expansion to the Rio Negro's south bank has led to the simultaneous upgrading and peripheralization of Iranduba. Yet, the building of a city-centric regional network of roadways also shaped Roraima State's transformation from isolated borderland to bypassed periphery. Moreover, financial and symbolic appropriations of standing rainforests by metropolitan conservationism marginalize remote communities even in the absence of exploitative deforestation and resource extraction. Final remarks emphasize the need for further research on the hybrid (urban—rural) conditions and functional articulations of distant-yet-impacted peripheries. Such efforts may broaden the political horizons of planetary urbanization by informing extensive contestations of entrepreneurial urbanism

The lag-phase during diauxic growth is a trade-off between fast adaptation and high growth rate

Bi-phasic or diauxic growth is often observed when microbes are grown in a chemically defined medium containing two sugars (for example glucose and lactose). Typically, the two growth stages are separated by an often lengthy phase of arrested growth, the so-called lag-phase. Diauxic growth is usually interpreted as an adaptation to maximise population growth in multi-nutrient environments. However, the lag-phase implies a substantial loss of growth during the switch-over. It therefore remains unexplained why the lag-phase is adaptive. Here we show by means of a stochastic simulation model based on the bacterial PTS system that it is not possible to shorten the lag-phase without incurring a permanent growth-penalty. Mechanistically, this is due to the inherent and well established limitations of biological sensors to operate efficiently at a given resource cost. Hence, there is a trade-off between lost growth during the diauxic switch and the long-term growth potential of the cell. Using simulated evolution we predict that the lag-phase will evolve depending on the distribution of conditions experienced during adaptation. In environments where switching is less frequently required, the lag-phase will evolve to be longer whereas, in frequently changing environments, the lag-phase will evolve to be shorter

Discovery of High-Affinity Protein Binding Ligands – Backwards

BACKGROUND: There is a pressing need for high-affinity protein binding ligands for all proteins in the human and other proteomes. Numerous groups are working to develop protein binding ligands but most approaches develop ligands using the same strategy in which a large library of structured ligands is screened against a protein target to identify a high-affinity ligand for the target. While this methodology generates high-affinity ligands for the target, it is generally an iterative process that can be difficult to adapt for the generation of ligands for large numbers of proteins. METHODOLOGY/PRINCIPAL FINDINGS: We have developed a class of peptide-based protein ligands, called synbodies, which allow this process to be run backwards--i.e. make a synbody and then screen it against a library of proteins to discover the target. By screening a synbody against an array of 8,000 human proteins, we can identify which protein in the library binds the synbody with high affinity. We used this method to develop a high-affinity synbody that specifically binds AKT1 with a K(d)<5 nM. It was found that the peptides that compose the synbody bind AKT1 with low micromolar affinity, implying that the affinity and specificity is a product of the bivalent interaction of the synbody with AKT1. We developed a synbody for another protein, ABL1 using the same method. CONCLUSIONS/SIGNIFICANCE: This method delivered a high-affinity ligand for a target protein in a single discovery step. This is in contrast to other techniques that require subsequent rounds of mutational improvement to yield nanomolar ligands. As this technique is easily scalable, we believe that it could be possible to develop ligands to all the proteins in any proteome using this approach