Review on the conversion of thermoacoustic power into electricity

Thermoacoustic engines convert heat energy into high amplitude acoustic waves and subsequently into electric power. This article provides a review of the four main methods to convert the (thermo)acoustic power into electricity. First, loudspeakers and linear alternators are discussed in a section on electromagnetic devices. This is followed by sections on piezoelectric transducers, magnetohydrodynamic generators, and bidirectional turbines. Each segment provides a literature review of the given technology for the field of thermoacoustics, focusing on possible configurations, operating characteristics, output performance, and analytical and numerical methods to study the devices. This information is used as an input to discuss the performance and feasibility of each method, and to identify challenges that should be overcome for a more successful implementation in thermoacoustic engines. The work is concluded by a comparison of the four technologies, concentrating on the possible areas of application, the conversion efficiency, maximum electrical power output and more generally the suggested focus for future work in the field.Comment: The following article appeared in J. Acoust. Soc. Am 143(2) and the final version in a proper two-column format may be found at: http://scitation.aip.org/content/asa/journal/jasa/143/2/10.1121/1.502339

Connecting foraging and roosting areas reveals how food stocks explain shorebird numbers

Shorebird populations, especially those feeding on shellfish, have strongly declined in recent decades and identifying the drivers of these declines is important for conservation. Changing food stocks are thought to be a key driver of these declines and may also explain why trends have not been uniform across Europe's largest estuary. We therefore investigated how winter population trends of Eurasian oystercatchers (Haematopus ostralegus) were linked to food availability in the Dutch Wadden Sea. Our analysis incorporated two spatial scales, a smaller scale focused on roost counting areas and food available to birds in these areas and a larger spatial scale of tidal basins. A novelty in our study is that we quantify the connectivity between roosting and foraging areas, identified from GPS tracking data. This allowed us to estimate food available to roosting birds and thus how food availability may explain local population trends. At the smaller spatial scale of roost counting areas, there was no clear relationship between available food and the number of roosting oystercatchers, indicating that other factors may drive population fluctuations at finer spatial scales. At the scale of tidal basins, however, there was a significant relationship between population trends and available food, especially cockle Cerastoderma edule,. Mortality and recruitment alone could not account for the large fluctuations in bird counts, suggesting that the site choice of wintering migratory oystercatchers may primarily drive these large fluctuations. Furthermore, the relationship between oystercatcher abundance and benthic food stocks, suggests winter shorebird counts could act as ecological indicators of ecosystem health, informing about the winter status of food stocks at a spatial scale of tidal basins

CombiFlow:combinatorial AML-specific plasma membrane expression profiles allow longitudinal tracking of clones

Acute myeloid leukemia (AML) often presents as an oligoclonal disease whereby multiple genetically distinct subclones can coexist within patients. Differences in signaling and drug sensitivity of such subclones complicate treatment and warrant tools to identify them and track disease progression. We previously identified >50 AML-specific plasma membrane (PM) proteins, and 7 of these (CD82, CD97, FLT3, IL1RAP, TIM3, CD25, and CD123) were implemented in routine diagnostics in patients with AML (n = 256) and myelodysplastic syndrome (n = 33). We developed a pipeline termed CombiFlow in which expression data of multiple PM markers is merged, allowing a principal component–based analysis to identify distinctive marker expression profiles and to generate single-cell t-distributed stochastic neighbor embedding landscapes to longitudinally track clonal evolution. Positivity for one or more of the markers after 2 courses of intensive chemotherapy predicted a shorter relapse-free survival, supporting a role for these markers in measurable residual disease (MRD) detection. CombiFlow also allowed the tracking of clonal evolution in paired diagnosis and relapse samples. Extending the panel to 36 AML-specific markers further refined the CombiFlow pipeline. In conclusion, CombiFlow provides a valuable tool in the diagnosis, MRD detection, clonal tracking, and understanding of clonal heterogeneity in AML

Correction:How the COVID-19 pandemic highlights the necessity of animal research (vol 30, pg R1014, 2020)

(Current Biology 30, R1014–R1018; September 21, 2020) As a result of an author oversight in the originally published version of this article, a number of errors were introduced in the author list and affiliations. First, the middle initials were omitted from the names of several authors. Second, the surname of Dr. van Dam was mistakenly written as “Dam.” Third, the first name of author Bernhard Englitz was misspelled as “Bernard” and the surname of author B.J.A. Pollux was misspelled as “Pullox.” Finally, Dr. Keijer's first name was abbreviated rather than written in full. These errors, as well as various errors in the author affiliations, have now been corrected online

Neo-adjuvant chemotherapy followed by surgery versus surgery alone in high-risk patients with resectable colorectal liver metastases: The CHARISMA randomized multicenter clinical trial

Background: Efforts to improve the outcome of liver surgery by combining curative resection with chemotherapy have failed to demonstrate de

Socio-cultural determinants of child mortality in Southern Peru: Including some methodological considerations

Among Amerindian children living at high altitude in the Andes in southern Peru, high child mortality rates have been reported in the literature, especially in the perinatal and neonatal period. We compared mortality rates in children calculated from retrospective survey data in 86 rural families from 2 Aymara and 3 Quechua peasant communities living at the same level of altitude (3825m) in southern Peru. Relations between land tenure, socio-cultural factors and child mortality were studied, and methodological considerations in this field of interest are discussed. Checks on consistency of empirical data showed evidence for underreporting of neonatal female deaths with birth order 3 and more. Perinatal (124 vs 34 per 1000 births) and infant mortality (223 vs 111 per 1000 live births) was significantly higher in Aymara compared with Quechua children, but no difference was found after the first year of life. A short pregnancy interval was associated with an elevated perinatal and infant mortality rate, and a similar albeit insignificant association was found with increased maternal age. Amount of land owned and birth order were not related with child mortality. Although levels of maternal education are generally low in both cultures, a consistent decline in infant and child mortality was found with the amount of years mothers had attended school. However, the results suggest a U-shaped relationship between the amount of years of parental education and perinatal mortality in offspring. Late fetal and early neonatal mortality were particularly high in one Aymara community where mothers were found to have more years of education. Infanticide, a known phenomenon in the highlands of the Andes, is discussed in relation with the findings of the study. Although maternal and child health services are utilized by the majority of families in 4 of 5 study communities, 43 of 51 mothers under the age of 45 years reported that they delivered their last baby in the absence of traditional midwives or official medical supervision.perinatal mortality child mortality neonatal mortality altitude land tenure Aymara Indians Quechua Indians Peru

Implementing a bidirectional impulse turbine into a thermoacoustic refrigerator

A thermoacoustic model is used to efficiently implement a bidirectional impulse turbine into a thermoacoustic refrigerator. Experiments are done for several gas types and mean pressures to identify its influence on the turbine efficiency. A scaling is investigated in an attempt to provide a unique function of the turbine efficiency for all operating conditions. Furthermore, the ratio of acoustic power absorbed by the turbine over to the total amount of available power is examined for varying conditions. Finally, the results are used to present a case study in which the turbine is used to drive the fluid pumps of the device. The remaining acoustic power is used for cooling, thus providing an off-grid thermoacoustic refrigerator that works purely with low-grade heat as an input