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This chapter explores Camus’s Myth of Sisyphus and The Plague to argue that plagues, and by implication pandemics, may be understood as examples of absurdity. The absurd may be understood as a more or less encompassing moment of meaninglessness that throws into question our habitual, taken-for-granted understandings of the world within which we live. While Myth advocates a capitulation to the absurd by accepting the meaninglessness of existence, The Plague advocates a more proactive position, in that its principal characters struggle to make new sense of their lives in the face of the plague. The problem of narrating the experience of plague is at the heart of the novel. The Plague may thereby be read as having important implications for how people have responded to Covid-19, specifically as a challenge to the habitual understanding of their lives and, akin to Camus’s plague, by anticipating a new and better future.

As I write, sport in Europe has returned to something like normal, despite the continuing restrictions caused by the pandemic. The Tour de France is in its first week, although the spectator though...

I recently came across an interview with the Norway and Sampdoria midfielder Morton Thorsby in the football magazine Blizzard (Velander 2021). The interview focuses on Thorsby’s commitment to envir...

We describe three cases of osteoarticular infection (OAI) in young thoroughbred horses in which the causative organism was identified by MALDI-TOF as Kingella species. The pattern of OAI resembled that reported with Kingella infection in humans. Analysis by 16S rRNA PCR enabled construction of a phylogenetic tree that placed the isolates closer to Simonsiella and Alysiella species, rather than Kingella species. Average nucleotide identity (ANI) comparison between the new isolate and Kingella kingae and Alysiella crassa however revealed low probability that the new isolate belonged to either of these species. This preliminary analysis suggests the organism isolated is a previously unrecognised species.

We argue that sport in general, and association football in particular, are activities that invite spectators and players alike to talk about them. Using a Wittgensteinian approach, we argued more ...

In the past half century, governments have increasingly relied on regulations—secondary legislation issued by administrative bodies and departments—to impose obligations on private parties, multiplying the occasions for regulatory interpretation. This article develops a theory of regulatory interpretation. It argues that such a theory involves understanding the authority of regulations. Turning to the public law of the UK, US, and Australia, this article identifies an intriguing similarity; in each case, regulations have authority when they rationally and non-arbitrarily implement delegated power within the means permitted by statute. The article then argues that this account of regulatory authority justifies a common approach to interpretation in which the object of interpretation is the purpose the regulation seeks to implement, discerned from the regulation’s text and accompanying explanation of its purpose, and constrained by background legal norms.

Ion implantation of Sm-ions has been tested in fabricating 2D detectors for microbeam radiation therapy (MRT). Sm-ions have been successfully implanted into fluoroaluminate (FA) glasses. The implantation concentration was chosen to be 5 × 1015 ions/cm2 and the ions were implanted at an energy of 2 MeV. After implantation, samarium ions resided within a thin plane very near the surface in the glass, which is expected to be beneficial for 2D imaging. Following implantation, photoluminescence (PL) spectra indicate that the embedded Sm-ions are in the form of Sm2+ and Sm3+. Subsequent annealing around the glass transition temperature (475 °C) converts all Sm2+ ions into Sm3+. Under X-ray irradiation, a partial conversion of Sm3+ into Sm2+ has been observed which may be used as measure of the X-ray dose delivered into the sample. QFRS (quadrature-frequency-resolved-spectroscopy) measurements on PL prominent emissions from Sm3+ and Sm2+ ions show that the PL decays associated with various transitions are in the 0.1 to 100 ms range (slow transitions). X-ray irradiation has led also to the appearance of broad and intense photoluminescence bands associated with X-ray induced structural defects in the host glass as confirmed in the unimplanted FA glasses. The generation of hole trapping centers in the host glass leads to the capture of photogenerated holes and thus allows the electrons to convert Sm3+ to Sm2+. Defect related PL decay signals were measured to be in the nanosecond region. These unwanted defect related fast decaying signals have been separated from slow Sm2+ and Sm3+ photoluminescence signals by using an “out-of-phase” PL measurements through a phase-sensitive photodetection technique with a modulated excitation laser diode and a lock-in amplifier. Overall, the Sm-ion implanted fluoroaluminate glass shows the successful conversion from the trivalent form of samarium (Sm3+) to the divalent form (Sm3+) under X-ray irradiation over a large dynamic range of X-ray intensities (800 Gy in air).

In October 2019, shortly before winning his sixth Formula One drivers’ championship title, Lewis Hamilton confessed through his Instagram account that he felt ‘like giving up on everything. Shut do...

As I write this editorial, another world cup has come round. This time it is the women’s T20. T20, for the uninitiated, is the shortest form of cricket. Each team has twenty overs (that’s 120 balls...

Microbeam radiation therapy (MRT) utilizes highly collimated synchrotron generated x-rays to create narrow planes of high dose radiation for the treatment of tumors. Individual microbeams have a typical width of 30-50 µm and are separated by a distance of 200-500 µm. The dose delivered at the center of the beam is lethal to cells in the microbeam path, on the order of hundreds of Grays (Gy). The tissue between each microbeam is spared and helps aid in the repair of adjacent damaged tissue. Radiation interactions within the peak of the microbeam, such as the photoelectric effect and incoherent (atomic Compton) scattering, cause some dose to be delivered to the valley areas adjacent to the microbeams. As the incident x-ray energy is modified, radiation interactions within a material change and affect the probability of interactions, as well as the directionality and energy of ionizing particles (electrons) that deposit energy in the valley regions surrounding the microbeam peaks. It is crucial that the valley dose between microbeams be minimal to maintain the effectiveness of MRT. Using a monochromatic x-ray source with x-ray energies ranging from 30 to 150 keV, a detailed investigation into the effect of incident x-ray energy on the dose profiles of microbeams was performed using samarium doped fluoroaluminate (FA) glass as the medium. All dosimetric measurements were carried out using a purpose-built fluorescence confocal microscope dosimetric technique that used Sm-doped FA glass plates as the irradiated medium. Dose profiles are measured over a very a wide range of x-ray energies at micrometer resolution and dose distribution in the microbeam are mapped. The measured microbeam profiles at different energies are compared with the MCNP6 radiation transport code, a general transport code which can calculate the energy deposition of electrons as they pass through a given material. The experimentally measured distributions can be used to validate the results for electron energy deposition in fluoroaluminate glass. Code validation is necessary for using transport codes in future treatment planning for MRT and other radiation therapies. It is shown that simulated and measured micro beam-profiles are in good agreement, and micrometer level changes can be observed using this high-resolution dosimetry technique. Full width at 10% of the maximum peak (FW@10%) was used to quantify the microbeam width. Experimental measurements on FA glasses and simulations on the dependence of the FW@10% at various energies are in good agreement. Simulations on energy deposited in water indicate that FW@10% reaches a local minimum around energies 140 keV. In addition, variable slit width experiments were carried out at an incident x-ray energy of 100 keV in order to determine the effect of the narrowing slit width on the delivered peak dose. The microbeam width affects the peak dose, which decreases with the width of the microbeam. Experiments suggest that a typical microbeam width for MRT is likely to be between 20-50 µm based on this work.

Talcott Edgar Frederick Parsons was an American sociologist who, as the principal exponent of what is known as structural functionalism, exerted a major influence over social theory in the middle part of the twentieth century. His work continues to be an important influence for German sociology. Primarily concerned with explaining the stability and order of social life, Parsons draws on ideas developed in cybernetics, in particular on what is known as systems theory. A system may be understood as a stable and organized structure that exists within an environment. Parsons argues that society, understood as a social system, must satisfy four functions if it is to remain stable.

Born near Stuttgart, Germany, the philosopher Max Horkheimer, who obtained his doctorate from the University of Frankfurt, is best known as a leader of the Frankfurt School, along with Theodor W. Adorno and Jürgen Habermas. From 1930 to 1958 (with a significant hiatus from 1934 to 1948), Horkheimer served as the Director of the Institut für Sozialforschung (Frankfurt Institute for Social Research), founded in 1923 to promote multidisciplinary research in the social sciences with a particular focus on Marxian thought; along with his colleague Adorno, Horkheimer was responsible for developing the distinctive form of Marxist philosophy that framed this research through the methodologies of German critical theory. Instead of just describing social systems through "objective" means, critical theory would endeavor to uncover the social context and raise questions about truth and social justice, acknowledging also that critical theory cannot produce universal truths. At best, the critical theorist simply expresses the contradictions and falsehoods of the society within which they work. Critical theory was applied in a sweeping analysis of Western civilization in Dialektik der Aufklärung (1947; Dialectic of Enlightenment), in which Adorno and Horkheimer argued that the progress of enlightened Western culture was simultaneously a regression into a new barbarism and an entanglement in myth. In modernist art, such as the work of James Joyce and Pablo Picasso, Horkheimer identified a crucial source of resistance to the political and economic oppression of late capitalist society. Horkheimer, who was Jewish, escaped Nazi Germany and taught at Columbia University from 1935 to 1941; he lived in Los Angeles during the 1940s, but eventually returned to Germany where died in Nuremburg in 1973.

The show jumper Ted Edgar passed away on 30 December 2018. He was one of the great characters of the sport in a golden age, from the 1950s to ‘70s. (He was also, purely incidentally, the cousin of ...

The storage phosphor material CsBr:Eu 2+ has been investigated for use in thermal neutron imaging. CsBr:Eu 2+ imaging plates were prepared in a polycrystalline form by cold pressing starting powders. These as-prepared materials show only small photostimulated luminescence intensity under thermal neutron irradiation, but the luminescence intensity can be increased by incorporating separate neutron converters, in the form of lithium, boron or gadolinium containing compounds. An imaging plate containing 5% 10 B 2 O 3 as a neutron converter has 50% the photostimulated luminescence intensity of a commercial Fuji neutron imaging plate. Thermal neutron imaging was shown to be possible with the CsBr:Eu 2+ -based imaging plates, and the differences in thermal neutron and X-ray images were clearly observed.

We report the photoluminescence, X-ray luminescence and scintillation properties of CaF 2 :Sm 2+ . Large single crystals of CaF 2 :Sm 2+ were grown by simply slow cooling of the calcium fluorite melt doped with samarium metal. The photoluminescence at room temperature shows a broad red 5d→4f emission band peaked at 725 nm which is well matched to the response of silicon photodetectors, and only a very weak Sm 3+ emission is observed. On cooling, the zero phonon lines of the Sm 2+ emission can be observed. The lifetime of the broad emission is short at room temperature (46 ns), but temperature dependent, and slows on cooling, reaching a constant value of 1.25 µs below 180 K. The X-ray luminescence comprises both red Sm 2+ and Sm 3+ emissions and a blue self-trapped exciton band for low Sm concentrations, but just the broad red emission Sm 2+ for highly doped (~1%) samples. The scintillation decay at room temperature shows two components, of 58 ns and 870 ns, in an integrated intensity ratio of 0.7:1 for a 0.1% Sm sample. The light output is around 15,000 photons/MeV when cooled by dry ice, with a scintillation decay time of 1.4 µs at that temperature. The performance of the material as an X-ray phosphor and scintillator is discussed.

The optical fluorescence, X-ray phosphor and scintillation properties of europium or samarium-doped solid solutions of strontium and barium chloride, together with their preparation and structure, are reported. Strontium chloride can accommodate up to 30% of barium ions on the strontium site whilst still retaining the cubic fluorite structure, and it is shown that that polycrystalline samples of volume ~1 cm 3 with high transparency can be produced. The increase in average atomic number provided by the barium content over pure strontium chloride means that strontium barium chloride with additional (divalent) europium or samarium doping shows good performance as an X-ray phosphor, emitting in the blue or red, respectively. The red-emitting samarium doped material is of particular significance as the emission is well matched to the spectral sensitivity of new silicon-based photodiodes. Europium-doped strontium barium chloride shows photoluminescence centred at 406 nm with a lifetime of 1.0 µs. As a scintillator, the conversion efficiency is 26,000 photons/MeV, and the decay time is 1.6 µs, whilst as an X-ray phosphor the relative brightness is 40% that of the commercial X-ray phosphor gadolinium oxysulphide doped with terbium. Samarium-doped strontium barium chloride shows intense red 4f 5 5d 1 →4f 6 emission at room temperature which switches to 4f 6 →4f 6 emission at low temperatures. The temperature–induced change in emission intensities and lifetimes is successfully modelled as a thermal crossover between 4f 5 5d 1 and 4f 6 excited states which are in close proximity. At room temperature, the 4f 5 5d 1 →4f 6 emission is centred at 680 nm and has a lifetime of 15 µs; the scintillation efficiency is 22,000 photons /MeV with a lifetime of 30 µs. As an X-ray phosphor, the efficiency compared to gadolinium oxysulphide doped with terbium is 30%. The role of native defects in the performance of the materials as scintillators and phosphors is briefly discussed.

We report the use of samarium-doped (Sm3 +) fluoroaluminate and fluorophosphate glasses for X-ray imaging. Incident X-rays convert samarium ions from the trivalent to the divalent state on a semi-permanent but erasable basis. Of the three fluorophosphate glass compositions investigated, that with the smallest fraction of phosphate bonds showed the greatest conversion, but fluoroaluminate glass showed better conversion than any of them. The effects of polyvalent co-dopants Ce, Eu, Pb, Sn, and In, (which may potentially act as electron donors or acceptors) on the conversion efficiency were investigated in fluoroaluminate glass, and whilst In and Sn inhibit the conversion, none of the co-dopants produced significant enhancement. The valence conversion may be used for X-ray imaging through the photoluminescence of the X-ray generated Sm2 + ions. With an optimal choice of the excitation wavelength and appropriate optical filtration in the camera-based recording system, very high-resolution X-ray imaging can be achieved. Recorded images show resolved detail down to the level of 25 μm, and the measured modulation transfer function extends out to 11 line pairs/mm.

Microbeam Radiation Therapy (MRT) is a promising cancer treatment technique. During the treatment, a micro-planar lattice of narrow X-ray beams called a microbeam (each narrow X-ray beam is typically 20–100 μm wide separated by 100–400 μm) delivers a very large dose (>1000 Gy) onto a tumor. Sm3+-doped glasses that involve the reduction of the Sm-valency (Sm3+ → Sm2+) upon X-ray irradiation are one of the potential dosimetric detectors for this particular application. With this class of detectors, we use the extent of valency reduction as a measure of the delivered X-ray dose, and the response read out using a confocal microscopic technique via the Sm2+/Sm3+ photoluminescence. This method enables us to measure the dose distribution of the microbeam. In this paper, we show that both Sm3+-doped fluorophosphate and fluoroaluminate glasses exhibit a dynamic range for the conversion response from 1 to over 1000 Gy, which satisfies the dose range for MRT applications. The dynamic range depends on the concentration of Sm3+ dopants as well as the detector glass composition. Moreover, X-ray induced absorbance, photobleaching and thermally-stimulated luminescence (TL) measurements suggest that the hole trapping process during X-ray irradiation is a dominant factor for the valency conversion, and the accommodation of precursor POHCs in fluorophosphate glasses gives rise to an acceleration of the conversion process.

highlights < Formation of transparent Ba0.3Sr0.7Cl2 in polycrystalline form. < X-ray phosphor materials with a resolution of at least 6 LP/mm. < Energy discrimination achieved with 'phoswich' structure based on emission wavelength. < Dual energy imaging technique allowing composition-sensitive imaging. abstract Polycrystalline solid state solutions of BaySr1 � yCl2 have been produced; these adopt the cubic fluorite phase for y � 0.30. The cubic structure minimizes optical scattering from grain boundaries, and so for y � 0.30 the materials are transparent, a key advantage for ceramic scintillators and phosphors. The substitution of Sr 2þ ions with Ba 2þ ions has the advantage that it substantially increases the x-ray ab- sorption coefficient with respect to pure SrCl2. Additional doping with rare earth ions such as Sm 2þ and Eu 2þ gives bright x-ray phosphor materials. The Sm or Eu-doped materials show a broad 4f 5 5d 1 / 4f 6 emission peaked at 685 nm or a broad 4f 6 5d 1 / 4f 7 emission peaked at 406 nm respectively. These materials have been tested as x-ray phosphors and the spatial resolution was determined to be at least 6 LP/mm, whilst the x-ray radioluminescence intensity is around 40% that of the commercial x-ray phosphor Gd2O2S:Tb. A stratified phoswich structure, comprising Eu and Sm-doped layers of BaySr1 � yCl2 was produced in which the relative intensities of the two emissions varies with x-ray beam energy; this can be used for energy discrimination in imaging by way of emission spectra as opposed to the more commonly used pulse shape discrimination. A dual energy imaging technique based on these bi-layered structures and utilizing a semi-professional grade digital SLR camera is described and composition- sensitive imaging has been demonstrated.

The fabrication of a series of novel, optically transparent, bulk plastic scintillators loaded with lithium methacrylate, and incorporating 2,5-diphenyloxazole and 5-phenyl-2-[4-(5-phenyl-1,3-oxazol-2-yl)phenyl]-1,3-oxazole fluorescent centres, is described. The attenuation length, photoluminescence, and both gamma ray and thermal neutron scintillation responses were compared over a range of lithium methacrylate concentrations. The maximum concentration corresponded to a weight percentage of lithium-6 of 0.63%. The photoluminescence shows a composite 2,5-diphenyloxazole and 5-phenyl-2-[4-(5-phenyl-1,3-oxazol-2-yl)phenyl]-1,3-oxazole broad band with vibronic features in the range 350–500 nm, and lifetimes in the range 0.9–2.7 ns. An increasing luminescence in a thermal neutron beam with increasing lithium-6 content is demonstrated.

Semi-transparent discs of polycrystalline CsBr:Eu2+ storage phosphor for X-ray imaging have been produced using a room temperature milling/pressing technique, and have been studied using infrared, and photoluminescence spectroscopies, together with scanning electron microscopy. The pressed discs are very sensitive to water vapour, and scanning electron microscopy shows that material undergoes a complete recrystallization following exposure to humid air for a few minutes through a room temperature hydration/crystallization process. Discs prepared by a simple mixture of CsBr and EuBr2 show photostimulated luminescence (PSL) at 440 nm without further processing, and the conversion efficiency is sufficient that X-ray imaging can be demonstrated. Discs which have been prepared by first sintering at 600 °C, then pressed, and finally hydrated at room temperature show very strong PSL with a conversion efficiency of ∼36 pJ mR−1 mm−3. A model is proposed for the generation of the active PSL centres in CsBr by the milling/hydration process.

The optical absorption and fluorescence spectra of polycrystalline cubic-phase barium chloride doped with divalent samarium is reported. X-ray diffraction shows that the cubic phase is stabilised at room temperature by the addition of 12.5% lanthanum trichloride; no evidence for the more common orthorhombic or hexagonal phases of barium chloride is found. Optical absorption measurements are in good agreement with a calculated spectrum for Sm2+ ions at a single site of cubic symmetry, even though the material must contain a substantial fraction of chlorine interstitials and lanthanum substitutional ions. The photoluminescence spectrum shows sharp red line emission from the 5D1 and 5D0 levels of the 4f6 configuration, again consistent with a single site of cubic symmetry, together with a broad emission, also in the red, which arises from the lowest levels of the 4f55d1 configuration. The relative strengths of these emissions are strongly temperature dependent; at room temperature the broad band from the lowest 4f55d1 levels peaking at 15,130 cm−1 is dominant, while at low temperature (∼12 K) sharp lines from the 5D0 level dominate. The most intense line corresponds to the 5D0→7F1 transition at 14,300 cm−1, but the nominally forbidden 5D0→7F0 transition also has significant intensity. The marked temperature dependence of the intensity of the lines and bands is successfully modelled by rate equations and is explained on the basis of thermally activated crossovers between the 4f6 (5D0,1) levels and the lowest levels of the 4f55d1 configuration; it is necessary to include the three lowest levels of the 4f55d1 configuration sandwiched between the 5D0 and 5D1 levels.

2 þ Computed radiography abstract The recent advancements in consumer-grade digital camera technology and the introduction of high- resolution, high sensitivity CsBr:Eu 2 þ storage phosphor imaging plates make possible a new cost- effective technique for X-ray imaging. The imaging plate is bathed with red stimulating light by high- intensity light-emitting diodes, and the photostimulated image is captured with a digital single-lens reflex (SLR) camera. A blue band-pass optical filter blocks the stimulating red light but transmits the blue photostimulated luminescence. Using a Canon D5 Mk II camera and an f1.4 wide-angle lens, the optical image of a 240 � 180 mm 2 Konica CsBr:Eu 2 þ imaging plate from a position 230 mm in front of the camera lens can be focussed so as to laterally fill the 35 � 23.3 mm 2 camera sensor, and recorded in 2808 � 1872 pixel elements, corresponding to an equivalent pixel size on the plate of 88 mm. The analogue-to-digital conversion from the camera electronics is 13 bits, but the dynamic range of the imaging system as a whole is limited in practice by noise to about 2.5 orders of magnitude. The modulation transfer function falls to 0.2 at a spatial frequency of 2.2 line pairs/mm. The limiting factor of the spatial resolution is light scattering in the plate rather than the camera optics. The limiting factors for signal-to-noise ratio are shot noise in the light, and dark noise in the CMOS sensor. Good quality images of high-contrast objects can be recorded with doses of approximately 1 mGy. The CsBr:Eu