Search

The NeuLAND (New Large-Area Neutron Detector) plastic-scintillator-based time-of-flight detector for 0.1-1.6 GeV neutrons is currently under construction at the Facility for Antiproton and Ion Research (FAIR), Darmstadt, Germany. In its final configuration, NeuLAND will consist of 3000 2.7 m $\times$ 5 cm $\times$ 5 cm big plastic scintillator bars that are read out on each end by fast timing photomultipliers. Here, data from a comprehensive study of an alternative light readout scheme using silicon photomultipliers (SiPM) are reported. For this purpose, a NeuLAND bar was instrumented on each end with a SiPM-based prototype of the same geometry as a 1'' photomultiplier tube, including four 6 $\times$ 6 mm$^2$ SiPMs, amplifiers, high voltage supply, and microcontroller. Tests were carried out using the 35 MeV electron beam from the superconducting Electron Linac for beams with high Brilliance and low Emittance (ELBE) with its picosecond-level time jitter in two different modes of operation, namely parasitic mode with one electron per bunch and single-user mode with 1-60 electrons per bunch. Acqiris fast digitisers were used for data acquisition. In addition, off-beam tests using cosmic rays and the NeuLAND data acquisition scheme have been carried out. Typical time resolutions of $\sigma_t\leq$ 120 ps were found for $\geq$95% efficiency for minimum ionising particles, improving on previous work at ELBE and exceeding the NeuLAND timing goal of $\sigma_t$ < 150 ps. Over a range of 10-300 MeV deposited energy in the NeuLAND bar, the gain was found to deviate by $\leq$10% ($\leq$20%) from linearity for 35 mm (75 mm) SiPM pitch, respectively, satisfactory for calorimetric use of the full NeuLAND detector. The dark rate of the prototype studied was found to be lower than the expected cosmic-ray induced background in NeuLAND., Comment: Submitted to Nucl. Inst. Meth. A

A deficiency in the implementation of current radiation protection is the determination of the ambient dose equivalent H*(10) and the directional dose equivalent H´(0.07) in pulsed radiation fields. Conventional dosimeter systems are not suitable for measurements in photon fields comprising short radiation pulses, which consequently leads to high detector loads in short time periods. Nevertheless, due to the implementation of advanced medical accelerators for cancer therapy, new medical diagnostic devices as well as various laser machining systems, there is an urgent need for suitable dosimeter systems for real time dosimetry. In this paper, a detector concept based on an organic scintillator and a full digital data analysis with the aim of developing a portable, battery powered measurement system is presented.

The excess energy emitted during the positronium (Ps) formation in condensed matter may be released as light. Spectroscopic analysis of this light can be a new method of studying the electronic properties of materials. We report the first experimental attempt, according to our knowledge, to verify the existence of this emission process. As a result, the possibility of the emission of photons during Ps formation is within the experimental uncertainty in two different solids: an n-alkane and porous silica. However, it seems that the Ps formation on the alkane surface is not accompanied by the emission of photons with energy in the detection range of 1.6 – 3.8 eV. Various processes that can influence the energy of the photon emitted during the Ps formation are discussed to elucidate this issue. To aid future experiments, equations were developed to estimate the expected ratio of light emission events to annihilation events with the presence or absence of a photon during the Ps formation.

The concept of an active dosimetry system for pulsed radiation dose rate measurements is presented. Real-time distinction of pulsed and non-pulsed radiation contributions is based on the time structure of a single interaction. A fast tissue equivalent plastic scintillator is exploited to minimize the pile-up effect influence on absorbed energy measurements. Being connected to a fully digital signal processing board, the detector creates an active dosimetry system with adjustable parameters. With this system, absorbed dose rate measurements were carried out in a photon field with a time structure mimicking a radiotherapeutic beam, but also in the presence of a constant radiation field. Measurements show a linear dependence of a pulsed radiation contribution on the accelerator current in the investigated range of the total dose rate up to 8 μGy h−1. While increasing the accelerator current by 1 μA, the pulsed radiation dose rate grows by (26.2 ± 0.9) nGy h−1 when considering pile-up events.

The 16O(n, α)13C reaction was proposed to be measured at the neutron time-of-flight (n_TOF) facility of CERN. To this purpose, a Double Frisch Grid Ionization Chamber (DFGIC) containing the oxygen atoms as a component in the counting gas coupled with a switch device in order to prevent the charge collection from the so-called γ-flash has been developed at Helmholtz-Zentrum Dresden-Rossendorf (HZDR), in Germany. The first 16O(n, α)13C measurement without seeing the charge of the γ-flash at n_TOF has been performed in November 2018. After the electronics did not suffer from the y-flash any more, another huge charge collection was discovered. Due to the high instantaneous flux at the n_TOF facility [1] the amount of that induced charge from neutron induced background reactions was piling up so much that the recognition of 16O(n, α)13C reactions from that background was very difficult. For that reason another 16O(n, α)13C measurement at the time-of-flight facility nELBE at HZDR which has a low instantaneous flux [2], has been performed in April 2019. Both measurements from n_TOF and nELBE will be presented here.

Herbal cannabis is one of the most consumed illegal drugs in Europe, with increasing local production. Illicit cannabis cultivation is not new to Western Europe. It first emerged on the scene in the 1970s, in the wake of the counter-culture following the 1968 Protests. Since then, it has gradually become more professional due to the increased diversification of involved actors, such as Organized Crime Groups (OCG), and the growing role of players linked to mafia organizations in both Italy and Albany. In Spain and France, where Moroccan resin has long dominated supply and demand, the cannabis market has seen a rise in herbal cannabis production. This, in turn, challenges the role of OCGs invested in resin importation. Yet, European marihuana production cannot be defined as a strictly criminal business. Small growers remain significant actors in production. This trend in production must be examined against evolving attitudes towards marihuana at the global level, linked especially to new legislation in the United States and in Canada.

Transcriptomic imputation approaches combine eQTL reference panels with large-scale genotype data in order to test associations between disease and gene expression. These genic associations could elucidate signals in complex genome-wide association study (GWAS) loci and may disentangle the role of different tissues in disease development. We used the largest eQTL reference panel for the dorso-lateral prefrontal cortex (DLPFC) to create a set of gene expression predictors and demonstrate their utility. We applied DLPFC and 12 GTEx-brain predictors to 40,299 schizophrenia cases and 65,264 matched controls for a large transcriptomic imputation study of schizophrenia. We identified 413 genic associations across 13 brain regions. Stepwise conditioning identified 67 non-MHC genes, of which 14 did not fall within previous GWAS loci. We identified 36 significantly enriched pathways, including hexosaminidase-A deficiency, and multiple porphyric disorder pathways. We investigated developmental expression patterns among the 67 non-MHC genes and identified specific groups of pre- and postnatal expression.

The \(^{16}\)O(n, \({\alpha }\))\(^{13}\)C reaction, as the inverse reaction of the astrophysically important \(^{13}\)C(\({\alpha }\), n)\(^{16}\)O reaction, is proposed to be measured at the neutron time-of-flight (n_TOF) facility of CERN. To this purpose, a Double Frisch Grid Ionization Chamber (DFGIC) containing the oxygen atoms as a component in the counting gas has been developed and a prototype was constructed at Helmholtz-Zentrum Dresden-Rossendorf(HZDR), in Germany. The first in-beam tests of the detector have been performed in November 2017 in the first (EAR1) and in April 2018 in the second (EAR2) experimental areas of the n_TOF at facility.

This paper presents the concept of an active dosimetry system and its operational regime for pulsed radiation dose rate measurements. The plastic scintillator is suggested to be used for absorbed dose rate measurements. As long as the detector can be considered tissue equivalent, the energy weighting of pile-up events in terms of the dose is achieved. The real-time distinction of pulsed and non-pulsed dose rate contributions is based on the time structure of a single interaction and requires only basic information about the beam time structure (pulses duration and period). The detector connected to a fully digital signal processing board creates an active dosimetry system with adjustable parameters. Such a system was used for absorbed dose rate measurements in pulsed photon field mimicking radiation field outside the bunker of a medical LINAC, but also in the presence of a constant radiation component. The results show a linear dependence of a pulsed radiation contribution on the accelerator current in the investigated range of the total dose rate up to 8 μGy/h.

The ubiquity of systems using artificial intelligence or "AI" has brought increasing attention to how those systems should be regulated. The choice of how to regulate AI systems will require care. AI systems have the potential to synthesize large amounts of data, allowing for greater levels of personalization and precision than ever before|applications range from clinical decision support to autonomous driving and predictive policing. That said, common sense reasoning [McCarthy, 1960] remains one of the holy grails of AI, and there exist legitimate concerns about the intentional and unintentional negative consequences of AI systems [Bostrom, 2003, Amodei et al., 2016, Sculley et al., 2014]. There are many ways to hold AI systems accountable. In this work, we focus on one: explanation. Questions about a legal right to explanation from AI systems was recently debated in the EU General Data Protection Regulation [Goodman and Flaxman, 2016, Wachter et al., 2017], and thus thinking carefully about when and how explanation from AI systems might improve accountability is timely. Good choices about when to demand explanation can help prevent negative consequences from AI systems, while poor choices may not only fail to hold AI systems accountable but also hamper the development of much-needed beneficial AI systems. Below, we briefly review current societal, moral, and legal norms around explanation, and then focus on the different contexts under which explanation is currently required under the law. We find that there exists great variation around when explanation is demanded, but there also exists important consistencies: when demanding explanation from humans, what we typically want to know is how and whether certain input factors affected the final decision or outcome. These consistencies allow us to list the technical considerations that must be considered if we desired AI systems that could provide kinds of explanations that are currently required of humans under the law. Contrary to popular wisdom of AI systems as indecipherable black boxes, we find that this level of explanation should often be technically feasible but may sometimes be practically onerous|there are certain aspects of explanation that may be simple for humans to provide but challenging for AI systems, and vice versa. As an interdisciplinary team of legal scholars, computer scientists, and cognitive scientists, we recommend that for the present, AI systems can and should be held to a similar standard of explanation as humans currently are; in the future we may wish to hold an AI to a different standard.

Rare-earth coordination polymers or lanthanide-organic frameworks with hitherto unreported crystal structures have been obtained on the basis of the "light" lanthanides Pr, Nd, Sm, and Eu in combination with terephthalic acid and using a slightly altered literature synthesis procedure. Rietveld refinement has shown that powder XRD patterns of such compounds are largely dominated by the positions of the heavy elements, pointing to isostructural networks for all four terephthalate-based materials. An in-depth luminescence study has been performed on the reported MOFs, showing rare praseodymium and samarium emission in the visible spectrum, aside from the strong europium luminescence and the near-infrared emission from both a terephthalate and 2,5-pyridinedicarboxylate based neodymium-MOF.

The detection of 200-1000 MeV neutrons requires large amounts, $\sim$100 cm, of detector material because of the long nuclear interaction length of these particles. In the example of the NeuLAND neutron time-of-flight detector at FAIR, this is accomplished by using 3000 monolithic scintillator bars of 270$\times$5$\times$5 cm$^3$ size made of a fast plastic. Each bar is read out on the two long ends, and the needed time resolution of $\sigma_t$ $, Comment: 12 pages, 11 figures

Politicians love to speak. It is what they do. It is who they are. Take away the podium, the microphone, and the words themselves, and, while the embodied person is still there, the politician quit...

Range verification is a very important point in order to fully exploit the physical advantages of protons compared to photons in cancer irradiation. Recently, a simple method has been proposed which makes use of the time of flight of protons in tissue and the promptly emitted secondary photons along the proton path (Prompt Gamma Timing, PGT). This has been considered so far for monoenergetic pencil beams only. In this work, it has been studied whether this technique can also be applied in passively formed irradiation fields with a so called spread out Bragg peak. Time correlated profiles could be recorded, which show a trend that is consistent with theoretical predictions.

The main background above 3\,MeV for in-beam nuclear astrophysics studies with $\gamma$-ray detectors is caused by cosmic-ray induced secondaries. The two commonly used suppression methods, active and passive shielding, against this kind of background were formerly considered only as alternatives in nuclear astrophysics experiments. In this work the study of the effects of active shielding against cosmic-ray induced events at a medium deep location is performed. Background spectra were recorded with two actively shielded HPGe detectors. The experiment was located at 148\,m below the surface of the Earth in the Reiche Zeche mine in Freiberg, Germany. The results are compared to data with the same detectors at the Earth's surface, and at depths of 45\,m and 1400\,m, respectively., Comment: Minor errors corrected; final version

The proton therapy in oncology requires instantaneous and reliable particle range verification, which can be achieved using prompt gamma emissions. The characteristic requirements of prompt gamma detection include the energy range of up to several MeV, increased background due to secondary emissions and high counting rates. Different concepts make use of the prompt gamma emissions for verification of dose deposition location, e.g. collimated systems or Compton cameras. Additionally to prompt gamma imaging, the prompt gamma timing method has been proposed, utilizing the proton transit time inside the body. Those approaches imply different needs on energy-, spatial- or timing-resolution of the detection system. Various scintillator materials with multiple shapes have been characterized with respect to those requirements using classical photomultiplier tubes (PMT) and different experimental setups and locations. The light output, non-linearity and energy resolution were measured using gamma sources. The timing was characterized at the ELBE facility at Helmholtz-Zentrum Dresden-Rossendorf (HZDR), using the bremsstrahlung beam with photons up to 12.5 MeV. Measurements at the 3 MV Tandetron accelerator at HZDR provided information of the energy resolution at therapy relevant energies of 4.4 MeV.

The characteristic dose profile of accelerated ions has opened up new horizons in the context of cancer treatment. However, particle range uncertainties strongly constrain the potentialities of ion beam therapy. In spite of worldwide efforts, a detector system for range and dose delivery assessment in real-time is not yet available for clinical routine.

Schizophrenia is a highly heritable disorder. Genetic risk is conferred by a large number of alleles, including common alleles of small effect that might be detected by genome-wide association studies. Here we report a multi-stage schizophrenia genome-wide association study of up to 36,989 cases and 113,075 controls. We identify 128 independent associations spanning 108 conservatively defined loci that meet genome-wide significance, 83 of which have not been previously reported. Associations were enriched among genes expressed in brain, providing biological plausibility for the findings. Many findings have the potential to provide entirely new insights into aetiology, but associations at DRD2 and several genes involved in glutamatergic neurotransmission highlight molecules of known and potential therapeutic relevance to schizophrenia, and are consistent with leading pathophysiological hypotheses. Independent of genes expressed in brain, associations were enriched among genes expressed in tissues that have important roles in immunity, providing support for the speculated link between the immune system and schizophrenia.

The web is creating networked markets that defy the old broadcast model of marketing. They are unwilling to be branded — they will not sit still for one-way marketing communications and they are too smart to accept simple-minded marketing messages. Instead they are busily engaged in honest, frank and wickedly funny conversations about products and companies they care about. In short, markets are now branding companies. Businesses must learn to join in these conversations. The first action to take: shut up and listen. Second, unplug the corporate orifice and enable and encourage everyone in your organisation to talk freely about what you do for a living.

A vanadium 2,6-naphthalenedicarboxylate, VIII(OH)(O2C–C10H6–CO2)·H2O, denoted as COMOC-3as (COMOC = Center for Ordered Materials, Organometallics and Catalysis, Ghent University), has been synthesized under hydrothermal conditions by means of both a solvothermal and a microwave synthesis procedure. The structure shows the topology of an aluminium 2,6-naphthalenedicarboxylate, the so-called MIL-69 (MIL = Materials of the Institute Lavoisier). After calcination at 250 °C in air, the VIII center was oxidized to VIV with the structure of VIVO(O2C–C10H6–CO2) (COMOC-3). The oxidation process was verified by cyclic voltammetry and EPR spectroscopy. The crystallinity was investigated by variable-temperature XRD. The title compound is stable against air and moisture. The catalytic performance of COMOC-3 was examined in the liquid-phase oxidation of cyclohexene. COMOC-3 exhibited similar catalytic performance to MIL-47 [VO(O2C–C6H4–CO2)]. The compound is reusable and maintains its catalytic activity through several runs.

Particle therapy in oncology is advantageous compared to classical radiotherapy due to its well-defined penetration depth. In the so-called Bragg peak, the highest dose is deposited; the tissue behind the cancerous area is not exposed. Different factors influence the range of the particle and thus the target area, e.g. organ motion, mispositioning of the patient or anatomical changes. In order to avoid over-exposure of healthy tissue and under-dosage of cancerous regions, the penetration depth of the particle has to be monitored, preferably already during the ongoing therapy session. The verification of the ion range can be performed using prompt gamma emissions, which are produced by interactions between projectile and tissue, and originate from the same location and time of the nuclear reaction. The prompt gamma emission profile and the clinically relevant penetration depth are correlated. Various imaging concepts based on the detection of prompt gamma rays are currently discussed: collimated systems with counting detectors, Compton cameras with (at least) two detector planes, or the prompt gamma timing method, utilizing the particle time-of-flight within the body. For each concept, the detection system must meet special requirements regarding energy, time, and spatial resolution. Nonetheless, the prerequisites remain the same: the gamma energy region (2 to 10 MeV), high counting rates and the stability in strong background radiation fields. The aim of this work is the comparison of different scintillation crystals regarding energy and time resolution for optimized prompt gamma detection.

Le marche francais du cannabis connait des changements propres a un marche arrive desormais a maturite et peut etre en consequence qualifie de marche du THC. L’entree de nouveaux concurrents, la diversification des produits, les variations de prix et l’augmentation de la qualite en sont les principales evidences ; ajoutons a cela la modification sociologique des structures d’offre. Ce document discute des implications que ces changements peuvent avoir sur le systeme traditionnel d’offre et sur les moyens mis en œuvre dans la lutte contre les stupefiants.

Marty Echt, the new head of marketing at Hunsk Engines, is determined to bring the motorcycle maker back to its roots. He says it's not enough to project authenticity to customers--employees must personally subscribe to the brand's values. Should the company's CEO support Marty's "real deal" vision? Five experts comment on this fictional case study. Bruce Weindruch, the founder and CEO of the History Factory, says that an authenticity-based campaign can be effective--but only if it's truly drawn from history. Marketers like Marty often remember their organization's past in a golden haze. Weindruch recommends exploring old engineering drawings, ads, and product photos in order to understand what customers and employees really valued back in the day. Gillian Arnold, a consultant to luxury fashion and fine jewelry brands, thinks Marty's approach is right: People in key marketing posts must be passionate about their products and know them inside and out. She argues that the CEO needs to commit more fully to the new campaign and address the significant gap between the staff and the brand. James H. Gilmore and B. Joseph Pine II, the cofounders of Strategic Horizons, point out that Hunsk needs to manage customers' perceptions rather than trying to be a "real company" or forming a management team whose personal interests match the brand. People purchase a product if it conforms to their self-image; that alone determines the brand's authenticity. Glenn Brackett of Sweetgrass Rods, a maker of bamboo fly-fishing rods, says Marty seems to be one of the few people who understand Hunsk motorcycles. If employees bring blood, sweat, heart, and soul to a product, it will manifest that spirit, and customers will line up for it.

The scaling limit of Si-based complementary metal oxide semiconductor (CMOS) transistors is approaching. The performance enhancement can no longer be guaranteed due to intrinsic mobility issues of silicon. The considerably higher charge carrier mobility of III-V compound semiconductors and Ge has led to renewed interest as these materials are considered for the development of transistors for 7 nm and 5 nm technology nodes [1-3]. Wet-chemical etching for surface and interface processing has proven to be effective for reducing defectivity. Due to the aggressive downscaling of transistors an ultimate etching selectivity and control at the nanometer and atomic-layer scale is required. Therefore, a thorough understanding of the interactions between the substrate and the solution (both chemical and electrochemical) is essential. In this work the etching kinetics of (100) III-As are discussed for various HCl/H2O2 compositions in the low pH range. The etch rates were determined by measuring the total amount of dissolved material with Inductively Coupled Plasma – Mass Spectrometry [4]. Electrochemical impedance measurements were performed to determine the band energetics of InGaAs during etching for various HCl/H2O2compositions. III-As can be etched in HCl solution in the presence of an oxidizing agent. In a first step the surface bonds are oxidized by H2O2. The formed III-As (hydr)oxides are subsequently dissolved by the acid. Fig. 1 shows the influence of the HCl concentration on the etch rate for InGaAs in 0.02 M H2O2 solution. For 0.01M HCl the dissolution kinetics are controlled by the wetting properties (i.e. surface termination): the etch rate decreases with increasing hydrophobicity. It was demonstrated that this is due to Cl-termination. The trend is comparable for GaAs and InAs [5, 6]. Electrochemical impedance measurements for InGaAs suggest that Cl termination results in a significant shift in flat-band potential (EFB) as shown in Fig. 1. The observed change in the band energetics has an important consequence for the dissolution mechanism of InGaAs. It can be shown that the mechanism for 0.01M HCl is both chemical and electrochemical, while for 1M HCl dissolution is mainly chemical. Such insight can, for instance, be used to influence the surface stoichiometry: suppressing the electrochemical mechanism lowers the build-up of elemental As0: InGaAs + 3h+ (VB) => In3+ + Ga3+ + As0 Fig. 2 shows the etch rate of Ge (100) as function of the H2O2 concentration for 1M and 6M HCl. Interestingly, the etching kinetics for Ge are also strongly influenced by the wetting properties. For 1M HCl, the surface ishydrophilic and the etch rate increases from 2O2. When the HCl concentration is increased to 6M, the surface becomes hydrophobic and the etch rate is lowered. These results suggests that Cl-termination is also important for the dissolution mechanism of Ge. Due to the low solubility of Ge suboxides [7], higher HCl concentrations are required to render the surface hydrophobic during etching. References [1] J. A. del Alamo, Nature, 479, 317 (2011). [2] R. Pillarisetty, Nature, 479, 324 (2011) [3] M. Heyns and W. Tsai, MRS Bull., 34, 485 (2009). [4] J. Rip, D. Cuypers, S. Arnauts, F. Holsteyns, D.H. van Dorp, S. De Gendt, ECS J. Solid State Sci. Technol., 3, N3064 (2014). [5] D.H. van Dorp, S. Arnauts, D. Cuypers, J. Rip, F. Holsteyns, S. De Gendt and J.J. Kelly, ECS J. Solid State Sci. Technol., 3, P179 (2014). [6] D. H. van Dorp, S. Arnauts, F. Holsteyns and S. De Gendt, ECS J. Solid State Sci. Technol. 4, N5061-N5066 (2015). [7] B. Onsia, T. Conard, S. De Gendt, M. Heyns, I. Hoflijk, P. Mertens, M. Meuris, G. Raskin, S. Sioncke, I. Teerlinck, A. Theuwis, J. Van Steenbergen, C Vinckier, Solid State Phenomena, 103-104, 27 (2005) Figure 1

With tagging, the readers of a Web resource (typically a Web page or a photograph posted on a photo-posting site) can associate a word or phrase with that resource; the resource can then be found by searching for that tag. Tagging is catching on with early adopters. It is likely to go mainstream because it empowers readers, it is social and it has business benefits. As tagging becomes popular, it will face challenges, including increased ambiguity of tags and tag spam.

Part I consists of abstracts from the following articles:THE HIDDEN POWER OF SOCIAL NETWORKSKNOWLEDGE STRATEGY AND INNOVATIONTHE FUTURE OF KNOWLEDGE MANAGEMENTMETADATA SPEAKS: THE THIRD ORDER OF ORDER AND THE VALUE OF THE UNSPOKEN