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Plotinus' Enneads is a work which is central to the history of philosophy in late antiquity. This is the second edition of the first English translation of the complete works of Plotinus in one volume in seventy years, which also includes Porphyry's Life of Plotinus. Led by Lloyd P. Gerson, a team of experts present up-to-date translations which are based on the best available text, the edition minor of Henry and Schwyzer and its corrections. The translations are consistent in their vocabulary, making the volume ideal for the study of Plotinus' philosophical arguments. This second edition includes a number of corrections, as well as additional cross-references to enrich the reader's understanding of Plotinus' sometimes very difficult presentation of his ideas. It will be invaluable for scholars of Plotinus with or without ancient Greek, as well as for students of the Platonic tradition.
Nearly 100 years ago, economist John Maynard Keynes predicted that, by today, technological advancements would allow the workweek to dwindle to just 15 hours, or 3 hours per day, and that the real problem of humanity would be filling their time with leisure. Although much has changed in the world of work since this prediction, such a drastic change has not taken place. In this article, several industrial-organizational psychology scholars discuss why this is the case. Why do we continue to work as much as we do, and how might that change? More fundamentally, what do these trends, contra Keynes’ prediction, tell us about the nature of work itself? We use this discussion to propose several research directions regarding the nature of work and how it might change in the future. We depict the phenomenon of working hours as multilevel in nature, and we consider both the positive and negative possible implications of working less than we do now.
The aim of this study was to determine whether there was a significant change in cardiac [123I]-metaiodobenzylguanidine uptake between baseline and follow-up in individuals with mild cognitive impairment with Lewy bodies (MCI-LB) who had normal baseline scans. Eight participants with a diagnosis of probable MCI-LB and a normal baseline scan consented to a follow-up scan between 2 and 4 years after baseline. All eight repeat scans remained normal; however, in three cases uptake decreased by more than 10%. The mean change in uptake between baseline and repeat was −5.2% (range: −23.8% to +7.0%). The interpolated mean annual change in uptake was −1.6%.
We present the second data release for the GaLactic and Extragalactic All-sky Murchison Widefield Array eXtended (GLEAM-X) survey. This data release is an area of 12 892-deg$^2$ around the South Galactic Pole region covering 20 h40 m$\leq$RA$\leq$6 h40 m, -90$^\circ$$\leq$Dec$\leq$+30$^\circ$. Observations were taken in 2020 using the Phase-II configuration of the Murchison Widefield Array (MWA) and covering a frequency range of 72–231 MHz with twenty frequency bands. We produce a wideband source finding mosaic over 170–231 MHz with a median root-mean-squared noise of $1.5^{+1.5}_{-0.5}$ mJy beam$^{-1}$. We present a catalogue of 624 866 components, including 562 302 components which are spectrally fit. This catalogue is 98% complete at 50 mJy, and a reliability of 98.7% at a 5 $\sigma$ level, consistent with expectations for this survey. The catalogue is made available via Vizier, and the PASA datastore and accompanying mosaics for this data release are made available via AAO Data Central and SkyView.
Campylobacter spp. are leading bacterial gastroenteritis pathogens. Infections are largely underreported, and the burden of outbreaks may be underestimated. Current strategies of testing as few as one isolate per sample can affect attribution of cases to epidemiologically important sources with high Campylobacter diversity, such as chicken meat. Multiple culture method combinations were utilized to recover and sequence Campylobacter from 45 retail chicken samples purchased across Norwich, UK, selecting up to 48 isolates per sample. Simulations based on resampling were used to assess the impact of Campylobacter sequence type (ST) diversity on outbreak detection. Campylobacter was recovered from 39 samples (87%), although only one sample was positive through all broth, temperature, and plate combinations. Three species were identified (Campylobacter jejuni, Campylobacter coli, and Campylobacter lari), and 33% of samples contained two species. Positive samples contained 1–8 STs. Simulation revealed that up to 87 isolates per sample would be required to detect 95% of the observed ST diversity, and 26 isolates would be required for the average probability of detecting a random theoretical outbreak ST to reach 95%. An optimized culture approach and selecting multiple isolates per sample are essential for more complete Campylobacter recovery to support outbreak investigation and source attribution.
Livestock abortion is a source of economic loss for farmers, but its economic impact has not been estimated in many Low and Middle-Income Countries. This article presents an estimation methodology and estimates for the gross and net cost of an abortion based on a sample of livestock-owning households in three regions of northern Tanzania and market data. We then generate aggregate estimates of abortion losses across Tanzania. We estimate annual gross and net annual losses of about $263 Million (about TZS 600 billion) and $131 million (about TZS 300 billion), respectively.
We present results from a pitcher-catcher experiment utilizing a proton beam generated with nanostructured targets at a petawatt-class, short-pulse laser facility to induce proton-boron fusion reactions in a secondary target. A 45-fs laser pulse with either 400 nm wavelength and 7 J energy, or 800 nm and 14 J, and an intensity of up to 5 × 1021 W/cm2 was used to irradiate either thin foil targets or near-solid density, nanostructured targets made of boron nitride (BN) nanotubes. In particular, for 800 nm wavelength irradiation, a BN nanotube target created a proton beam with about five times higher maximum energy and about ten times more protons than a foil target. This proton beam was used to irradiate a thick plate made of boron nitride placed in close proximity to trigger 11B (p, α) 2α fusion reactions. A suite of diagnostics consisting of Thomson parabola ion spectrometers, postshot nuclear activation measurements, neutron time-of-flight detectors, and differentially filtered solid-state nuclear track detectors were used to measure both the primary proton spectrum and the fusion products. From the primary proton spectrum, we calculated (p, n) and (α,n) reactions in the catcher and compare with our measurements. The nuclear activation results agree quantitatively and neutron signals agree qualitatively with the calculations, giving confidence that primary particle distributions can be obtained from such measurements. These results provide new insights for measuring the ion distributions inside of proton-boron fusion targets.
Floating, mixed-valent Fe films have been observed worldwide in wetlands, ferrous iron-rich seeps, and in seasonally reduced soils, but are usually misidentified as oil or biofilms. There has been little characterization or explanation of their formation. Along the Oregon coast such films were found on ephemeral pools where Fe(II)-rich groundwater (∼100 µM Fe) has been discharged at the base of Pleistocene sand dunes. Fe(II) oxidized to Fe(III) at the air-water interface to form ∼100–300 nm thick films. Analyses indicated that the films contained both Fe(III) and Fe(II) in a ratio of 3:1; Si was the other main cation; OH was the main anion and some C was also identified. The film morphology was flat under optical and electron microscopy with some attached floccules having a string-like morphology. Energy-filtered electron diffraction patterns showed three diffraction rings at 4.5, 2.6 and 1.4 Å in some places and two rings (2.6 and 1.4 Å) in others. Upon further oxidation the films became 2-line ferrihydrite. We are proposing the name ‘schwimmeisen’ for the floating, mixed-valent Fe film.
The paper examines the introduction of trained female nurses for the British army men in colonial India between 1888 and 1920. It discusses the genesis of the Indian Nursing Service (INS), including the background and negotiations leading up to its formation, terms of employment, duties and working conditions of the nursing sisters. The memoir of Catharine Grace Loch, who served as the first Chief Lady Superintendent of the service is used extensively to trace the early experiences and challenges of the nursing sisters. The paper primarily argues that the INS being a new service, the colonial government maintained tight control over its functioning, and extreme conservatism in spending, thus retarding the growth of professional army nursing in India. Secondly, in examining the relations between the sisters and the (male) nursing orderlies, sub-medical and medical officers, the paper argues that the inadequate delineation of the nursing sisters’ position in the military medical hierarchy was an important reason for the undermining of their expertise and status. Thirdly, the paper contends that as an all-women service, nursing constituted an important avenue of female agency within the patriarchal colonial establishment, which subjected the sisters to scrutiny both professionally and socially. The paper analyses the resultant conditions and regulations imposed on the sisters – most of them determined by gender and class notions. Finally, the paper discusses the gradual establishment and recognition of the service as an important cornerstone for the health of the army, while highlighting the shortcomings that yet persisted up until 1920.
Data from a national survey of 348 U.S. sports field managers were used to examine the effects of participation in Cooperative Extension events on the adoption of turfgrass weed management practices. Of the respondents, 94% had attended at least one event in the previous 3 yr. Of this 94%, 97% reported adopting at least one practice as a result of knowledge gained at an Extension turfgrass event. Half of the respondents had adopted four or more practices; a third adopted five or more practices. Nonchemical, cultural practices were the most-adopted practices (65% of respondents). Multiple regression analysis was used to examine factors explaining practice adoption and Extension event attendance. Compared to attending one event, attending three events increased total adoption by an average of one practice. Attending four or more events increased total adoption by two practices. Attending four or more events (compared to one event) increased the odds of adopting six individual practices by 3- to 6-fold, depending on the practice. This suggests that practice adoption could be enhanced by encouraging repeat attendance among past Extension event attendees. Manager experience was a statistically significant predictor of the number of Extension events attended but a poor direct predictor of practice adoption. Experience does not appear to increase adoption directly, but indirectly, via its impact on Extension event attendance. In addition to questions about weed management generally, the survey asked questions specifically about annual bluegrass management. Respondents were asked to rank seven sources of information for their helpfulness in managing annual bluegrass. There was no single dominant information source, but Extension was ranked more than any other source as the most helpful (by 22% of the respondents) and was ranked among the top three by 53%, closely behind field representative/local distributor sources at 54%.
You have just placed an epidural in a 19-year-old pregnant female with no prior medical history. After a negative test dose, the epidural is bolused with a bupivacaine and fentanyl mixture. After 10 minutes, the patient’s blood pressure is 80/40 mm Hg. The fetal monitor is showing late decelerations. What do you do?
Substantially expanded and updated, the new edition of this classic textbook provides unrivalled coverage of the fundamentals of power electronics. Comprehensive coverage of foundational concepts in circuits, magnetics, devices, dynamic models, and control establishes a strong conceptual framework for further study. Extensive discussion of contemporary practical considerations, enhanced by real-world examples, prepares readers for design scenarios ranging from low-power dc/dc converters to multi-megawatt ac machine drives. New topics include SiC and GaN wide-bandgap materials, superjunction MOSFET and IGBT devices, advanced magnetics design, multi-level and switched-capacitor converters, RF converter circuits, and EMI. Over 300 new and revised end-of-chapter problems enhance and expand understanding of the material, with solutions for instructors. Unique in its breadth and depth, and providing a range of flexible teaching pathways at multiple levels, this is the definitive guide to power electronics for graduate and senior undergraduate students in electrical engineering, and practicing electrical engineers.
In Part I we examined the form and function ofthe major families of power electronic converters.Our goal was to show how the intended powerconversion function is achieved in each case byappropriate configuration of the circuitcomponents and by proper operation of theswitches. Throughout those earlier chapters, ourconcern was with nominal operating conditions, that is,the ideal operating conditions in which aconverter is designed to perform its primaryconversion function. As nominal operation in mostpower electronic circuits involves a periodic steady state, wefocused on situations in which circuit operationand behavior are the same from cycle to cycle.
Power magnetics are often constrained by loss.Consequently, the ability to accurately predictthe loss of a magnetic component is extremelyvaluable for design. The techniques for modelingmagnetics loss introduced in the previous chaptersare useful, but do not adequately cover allsituations. In this chapter we introduce refinedmethods to predict winding and core losses inmagnetic components, with particular emphasis onfactors (such as proximity effect) that becomedominant at high frequencies and on cases wherethe waveforms are not purely dc or sinusoidal.
We add transformers to the topology of ahigh-frequency converter for three reasons: toprovide electrical isolation between two (or more)external systems; to reduce the component stressesthat result when the input/output conversion ratiois far from unity; and to create multiple relatedoutputs in a simple manner. (We showed therelationship between switch-stress factor and theconversion ratio in Fig. 5.26.) There are manyways in which we can include the transformer inthe topology of a dc/dc converter; we present anddiscuss some of them in this chapter.
Power electronic circuits change the characterof electrical energy: from dc or ac to ac or dc,from one voltage level or frequency to another, orin some other way. We refer to such circuitsgenerically as converters, staticconverters (because they contain nomoving parts), powerprocessors, or powerconditioners. The part of the system thatactually manipulates the flow of energy is thepower circuit. It isthe scaffold for the system’s other components,such as the control circuit or the thermalmanagement parts.
The rapid switching transitions of a powerconverter are potential sources of electromagneticinterference (EMI), both for the converter itselfand for the systems to which it is connected.Adequate filtering at the input and output of theconverter is important, both to obtain acceptableperformance and to prevent interference with otherequipment. In this chapter, we consider thesources of EMI in a converter, how EMI is measuredand modeled, and how it can be mitigated, with afocus on conducted (rather than radiated) EMI.
The previous chapters on magnetics provided thekey concepts needed to analyze, model, and designmagnetic components such as inductors andtransformers. The purpose of this chapter is torefine and extend the methods introduced there,with a focus on techniques for magnetic componentdesign. In particular, we introduce design methodsand sizing considerations for efficientlyconverging on an appropriate design. Thisincludes, for example, approximate methods forsizing the magnetic core for an inductor ortransformer, and metrics for comparing magneticmaterials.