Spectral analysis of Monte Carlo calculated fluence correction and cema conversion factors for high-energy photon beams at different depths

Purpose: The aim of this study is to investigate the depth-dependent detector response of detailed thimble air-filled ionization chambers by calculating spectral charged particle fluence correction factors at different depths in water. Those spectral correction factors will help to understand, how the detector response varies at different depths and what kind of influences disparate effects have on the spectral detector response.Methods: The cema-approach can be used to obtain spectral charged particle fluence-based correction factors for various measurement conditions by substituting the commonly well-known dose conversion factor with a conversion factor based on the dosimetric quantity cema (“converted-energy per unit mass”). The resulting spectral fluence correction factors were calculated with the EGSnrc software toolkit and analyzed for two air-filled cylindrical ionization chambers (PTW type 31021 Semiflex 3D, SNC125c™) at different depths in a water phantom irradiated with a 6 MV linear accelerator x-ray spectrum. The ionization chamber models have been stepwise decomposed to investigate the perturbation caused by internal and external effects on the fluence distribution within the detector.Results: Monte Carlo calculated fluence-based perturbation correction factors revealed that for all investigated detectors, considerable fluence disturbances occur, especially in the build-up region of depth-dose curves. Our results have shown that even slight variations in depth can have major consequences on the differential charged particle fluence within the ionization chamber, mainly due to internal cavity-specific effects. Furthermore, the results showed that in the case of relative dose measurements, the depth-depending detector response can significantly differ from unity in a range of 1.4%–2.8% depending on the ionization chamber design.Conclusion: The complexity of different effects on the fluence disturbance could be broken down with regard to their influence on the spectral fluence distribution in the sensitive volume of the investigated detectors. It could be demonstrated, that the displacement of water is a depth-depending effect, which can not be compensated or corrected ideally for each investigated water depth by the shift of the effective point of measurement. Generally, the spectral analysis of those energy-dependent correction factors serves to a deeper understanding of the detector response under various conditions

Layered Drawing of Undirected Graphs with Generalized Port Constraints

The aim of this research is a practical method to draw cable plans of complex machines. Such plans consist of electronic components and cables connecting specific ports of the components. Since the machines are configured for each client individually, cable plans need to be drawn automatically. The drawings must be well readable so that technicians can use them to debug the machines. In order to model plug sockets, we introduce port groups; within a group, ports can change their position (which we use to improve the aesthetics of the layout), but together the ports of a group must form a contiguous block. We approach the problem of drawing such cable plans by extending the well-known Sugiyama framework such that it incorporates ports and port groups. Since the framework assumes directed graphs, we propose several ways to orient the edges of the given undirected graph. We compare these methods experimentally, both on real-world data and synthetic data that carefully simulates real-world data. We measure the aesthetics of the resulting drawings by counting bends and crossings. Using these metrics, we compare our approach to Kieler [JVLC 2014], a library for drawing graphs in the presence of port constraints.Comment: Appears in the Proceedings of the 28th International Symposium on Graph Drawing and Network Visualization (GD 2020

Replication factory activation can be decoupled from the replication timing program by modulating Cdk levels

In the metazoan replication timing program, clusters of replication origins located in different subchromosomal domains fire at different times during S phase. We have used Xenopus laevis egg extracts to drive an accelerated replication timing program in mammalian nuclei. Although replicative stress caused checkpoint-induced slowing of the timing program, inhibition of checkpoint kinases in an unperturbed S phase did not accelerate it. Lowering cyclin-dependent kinase (Cdk) activity slowed both replication rate and progression through the timing program, whereas raising Cdk activity increased them. Surprisingly, modest alteration of Cdk activity changed the amount of DNA synthesized during different stages of the timing program. This was associated with a change in the number of active replication factories, whereas the distribution of origins within active factories remained relatively normal. The ability of Cdks to differentially effect replication initiation, factory activation, and progression through the timing program provides new insights into the way that chromosomal DNA replication is organized during S phase

Thermal Phase Mixing During First Order Phase Transitions

The dynamics of first order phase transitions are studied in the context of (3+1)-dimensional scalar field theories. Particular attention is paid to the question of quantifying the strength of the transition, and how `weak' and `strong' transitions have different dynamics. We propose a model with two available low temperature phases separated by an energy barrier so that one of them becomes metastable below the critical temperature $T_c$. The system is initially prepared in this phase and is coupled to a thermal bath. Investigating the system at its critical temperature, we find that `strong' transitions are characterized by the system remaining localized within its initial phase, while `weak' transitions are characterized by considerable phase mixing. Always at $T_c$, we argue that the two regimes are themselves separated by a (second order) phase transition, with an order parameter given by the fractional population difference between the two phases and a control parameter given by the strength of the scalar field's quartic self-coupling constant. We obtain a Ginzburg-like criterion to distinguish between `weak' and `strong' transitions, in agreement with previous results in (2+1)-dimensions.Comment: 28 pages RevTeX, 9 postscript figures, IMPERIAL/TP/93-94/58, DART-HEP-94/0

Proton Magnetic Resonance Spectroscopy Reveals Neuroprotection by Oral Minocycline in a Nonhuman Primate Model of Accelerated NeuroAIDS

Background: Despite the advent of highly active anti-retroviral therapy (HAART), HIV-associated neurocognitive disorders continue to be a significant problem. In efforts to understand and alleviate neurocognitive deficits associated with HIV, we used an accelerated simian immunodeficiency virus (SIV) macaque model of NeuroAIDS to test whether minocycline is neuroprotective against lentiviral-induced neuronal injury. Methodology/Principal Findings: Eleven rhesus macaques were infected with SIV, depleted of CD8+ lymphocytes, and studied until eight weeks post inoculation (wpi). Seven animals received daily minocycline orally beginning at 4 wpi. Neuronal integrity was monitored in vivo by proton magnetic resonance spectroscopy and post-mortem by immunohistochemistry for synaptophysin (SYN), microtubule-associated protein 2 (MAP2), and neuronal counts. Astrogliosis and microglial activation were quantified by measuring glial fibrillary acidic protein (GFAP) and ionized calcium binding adaptor molecule 1 (IBA-1), respectively. SIV infection followed by CD8+ cell depletion induced a progressive decline in neuronal integrity evidenced by declining N-acetylaspartate/creatine (NAA/Cr), which was arrested with minocycline treatment. The recovery of this ratio was due to increases in NAA, indicating neuronal recovery, and decreases in Cr, likely reflecting downregulation of glial cell activation. SYN, MAP2, and neuronal counts were found to be higher in minocycline-treated animals compared to untreated animals while GFAP and IBA-1 expression were decreased compared to controls. CSF and plasma viral loads were lower in MN-treated animals. Conclusions/Significance: In conclusion, oral minocycline alleviates neuronal damage induced by the AIDS virus

Slaughter weight rather than sex affects carcass cuts and tissue composition of Bisaro pigs

Carcass cuts and tissue composition were assessed in Bisaro pigs (n=64) from two sexes (31 gilts and 33 entire males) reared until three target slaughter body-weights (BW) means: 17 kg, 32 kg, and 79 kg. Dressing percentage and backfat thickness increased whereas carcass shrinkage decreased with increasing BW. Slaughter weight affected most of the carcass cut proportions, except shoulder and thoracic regions. Bone proportion decreased linearly with increasing slaughter BW, while intermuscular and subcutaneous adipose tissue depots increased concomitantly. Slaughter weight increased the subcutaneous adipose tissue proportion but this impaired intramuscular and intermuscular adipose tissues in the loin primal. The sex of the pigs minimally affected the carcass composition, as only the belly weight and the subcutaneous adipose tissue proportions were greater in gilts than in entire males. Light pigs regardless of sex are recommended to balance the trade-offs between carcass cuts and their non-edible compositional outcomes.Work included in the Portuguese PRODER research Project BISOPORC – Pork extensive production of Bísara breed, in two alternative systems: fattening on concentrate vs chesnut, Project PRODER SI I&DT Medida 4.1 “Cooperação para a Inovação”. The authors are grateful to Laboratory of Carcass and Meat Quality of Agriculture School of Polytechnic Institute of Bragança ‘Cantinho do Alfredo’. The authors are members of the MARCARNE network, funded by CYTED (ref. 116RT0503).info:eu-repo/semantics/publishedVersio

Photography-based taxonomy is inadequate, unnecessary, and potentially harmful for biological sciences

The question whether taxonomic descriptions naming new animal species without type specimen(s) deposited in collections should be accepted for publication by scientific journals and allowed by the Code has already been discussed in Zootaxa (Dubois & Nemésio 2007; Donegan 2008, 2009; Nemésio 2009a–b; Dubois 2009; Gentile & Snell 2009; Minelli 2009; Cianferoni & Bartolozzi 2016; Amorim et al. 2016). This question was again raised in a letter supported by 35 signatories published in the journal Nature (Pape et al. 2016) on 15 September 2016. On 25 September 2016, the following rebuttal (strictly limited to 300 words as per the editorial rules of Nature) was submitted to Nature, which on 18 October 2016 refused to publish it. As we think this problem is a very important one for zoological taxonomy, this text is published here exactly as submitted to Nature, followed by the list of the 493 taxonomists and collection-based researchers who signed it in the short time span from 20 September to 6 October 2016

Hybrid cosmic ray measurements using the IceAct telescopes in coincidence with the IceCube and IceTop detectors

IceAct is a proposed surface array of compact (50 cm diameter) and cost-effective Imaging Air Cherenkov Telescopes installed at the site of the IceCube Neutrino Observatory at the geographic South Pole. Since January 2019, two IceAct telescope demonstrators, featuring 61 silicon photomultiplier (SiPM) pixels have been taking data in the center of the IceTop surface array during the austral winter. We present the first analysis of hybrid cosmic ray events detected by the IceAct imaging air-Cherenkov telescopes in coincidence with the IceCube Neutrino Observatory, including the IceTop surface array and the IceCube in-ice array. By featuring an energy threshold of about 10 TeV and a wide field-of-view, the IceAct telescopes show promising capabilities of improving current cosmic ray composition studies: measuring the Cherenkov light emissions in the atmosphere adds new information about the shower development not accessible with the current detectors, enabling significantly better primary particle type discrimination on a statistical basis. The hybrid measurement also allows for detailed feasibility studies of detector cross-calibration and of cosmic ray veto capabilities for neutrino analyses. We present the performance of the telescopes, the results from the analysis of two years of data, and an outlook of a hybrid simulation for a future telescope array

Three-year performance of the IceAct telescopes at the IceCube Neutrino Observatory

IceAct is an array of compact Imaging Air Cherenkov Telescopes at the ice surface as part of the IceCube Neutrino Observatory. The telescopes, featuring a camera of 61 silicon photomultipliers and fresnel-lens-based optics, are optimized to be operated in harsh environmental conditions, such as at the South Pole. Since 2019, the first two telescopes have been operating in a stereoscopic configuration in the center of IceCube\u27s surface detector IceTop. With an energy threshold of about 10 TeV and a wide field-of-view, the IceAct telescopes show promising capabilities of improving current cosmic-ray composition studies: measuring the Cherenkov light emissions in the atmosphere adds new information about the shower development not accessible with the current detectors. First simulations indicate that the added information of a single telescope leads, e.g., to an improved discrimination between flux contributions from different primary particle species in the sensitive energy range. We review the performance and detector operations of the telescopes during the past 3 years (2020-2022) and give an outlook on the future of IceAct

Vitamin D levels and disease activity in patients with juvenile idiopathic arthritis

Einleitung: Die juvenile idiopathische Arthritis (JIA) ist mit einer Prävalenz von rund 1:1000 die häufigste chronische entzündlich-rheumatische Erkrankung des Kindes- und Jugendalters. Der Terminus JIA umfasst eine heterogene Gruppe von Erkrankungen, die sich in Klinik, Pathogenese und Therapie unterscheiden. Jede Form der JIA kann zu gravierenden funktionellen Einschränkungen und Folgeschäden führen. Es stehen moderne und wirksame, aber kostenintensive Therapiekonzepte zur Verfügung.Während für einige Autoimmunerkrankungen des Erwachsenenalters belastbare Daten zum Einfluss des Vitamin-D-Spiegels auf Häufigkeit und Verlauf der Erkrankungen vorliegen, gibt es nur wenige Erkenntnisse zur JIA. In dieser Arbeit wurden die Häufigkeit eines Vitamin-D-Mangels bei JIA-Patienten sowie Zusammenhänge zwischen Vitamin-D-Serumspiegel und der Krankheitsaktivität, Therapie und dem Auftreten einer Uveitis im Verlauf der JIA untersucht.Methoden: Zwei Patientenkollektive wurden analysiert: 1) Im Sozialpädiatrischen Zentrum der Charité – Universitätsmedizin Berlin (SPZ) wurden 2015 über 2000 Krankenakten durchgesehen. Für 214 Kinder und Jugendliche mit JIA und Vitamin-D-Spiegelbestimmung im Rahmen der klinischen Routine wurden Parameter zur Krankheitsaktivität und Therapie aus der Patientendokumentation standardisiert erfasst. 2) Aus der bundesweiten prospektiven ICON-Kohorte wurden Daten von 360 JIA-Patienten ausgewertet, für die Vitamin-D-Spiegel vorlagen.Vitamin-D-Serumspiegel [25(OH)D] unter 20 ng/ml wurden in dieser Arbeit als Vitamin-D-Mangel definiert, Werte ≥ 28 ng/ml als ausreichende Versorgung, Werte dazwischen als Vitamin-D-Insuffizienz. Untersucht wurden i) die Häufigkeit eines Vitamin-D-Mangels bei Patienten beider JIA-Kollektive im Vergleich zu Kontrollen aus der Bevölkerung (KiGGS-Studie des Robert-Koch-Instituts), ii) Merkmale, die mit einem Vitamin-D-Mangel assoziiert sind, iii) Zusammenhänge zwischen den 25(OH)D-Spiegeln bei den ICON-Patienten und der Krankheitsaktivität sowie der Entwicklung einer Uveitis. Die statistische Auswertung erfolgte mit dem Programmpaket SAS am Deutschen Rheuma-Forschungszentrum Berlin.Ergebnisse: In beiden JIA-Patientenkollektiven wurde eine hohe Prävalenz von Vitamin-D-Mangel (44 % ICON, 61 % SPZ) ermittelt, diese bestand jedoch auch in der Allgemeinbevölkerung (62 % KiGGS). Durchschnittlich lag der Vitamin-D-Spiegel bei 22,8 ng/ml (ICON); 19,0 ng/ml (SPZ) und 19,1 ng/ml (KiGGS). Ein Vitamin-D-Mangel war häufiger bei Jugendlichen (≥12 Jahre), bei Migrationshintergrund und in den Monaten von Oktober bis April.Bei den ICON-Patienten bestand eine signifikante negative Korrelation zwischen Vitamin-D-Spiegel und der Krankheitsaktivität, sowie der Inzidenz einer Uveitis. Patienten mit Vitamin-D-Spiegeln ≥ 28ng/ml erhielten seltener eine Therapie mit einem krankheitsmodifizierenden Medikament (DMARD, Disease modifying antirheumatic drug).Zusammenfassung: JIA-Patienten haben häufig einen Vitamin-D-Mangel, wenngleich nicht häufiger als die Bevölkerung. Dieser scheint sich negativ auf den Krankheitsverlauf und das Auftreten einer Uveitis auszuwirken. In weiteren Untersuchungen sollte dieser Befund überprüft und ermittelt werden, welche Vitamin-D-Versorgung zur Senkung der Krankheitsaktivität und Reduktion extraartikulärer Manifestationen bei JIA beitragen kann.Angesichts der Präventionsmöglichkeiten eines Vitamin-D-Mangels sind diese Ergebnisse von erheblicher klinischer Relevanz.Introduction: Juvenile idiopathic arthritis (JIA) is the most common chronic inflammatory rheumatic disease in childhood and adolescence with a prevalence of around 1:1000. The term JIA covers a heterogeneous group of diseases that differ in clinical presentation, pathogenesis and therapy. Any form of JIA can lead to serious functional limitations and consequential damage. Modern and effective, yet costly therapy-concepts are available.While reliable data on the influence of vitamin D serum levels on the frequency and course of diseases exist for some adult autoimmune diseases, there is little information for JIA. This thesis investigates the relationship between vitamin D serum levels and disease activity, the occurrence of concomitant diseases and the course of JIA.Methods: Two patient groups were analysed: 1) In 2015, >2000 medical records of children and adolescents treated in the Center for Chronically Sick Children of the Charité - Universitätsmedizin Berlin (CCSC) were reviewed. For 214 children with JIA and vitamin D measurements during clinical routine, clinical parameters were extracted from the patient records in a standardised manner. 2) 360 JIA patients from the nationwide prospective ICON cohort with data for vitamin D levels were analysed.Vitamin-D-serum-levels [25(OH)D] below 20 ng/ml were defined as vitamin D deficiency, values ≥ 28 ng/ml as sufficient supply, values in between as vitamin D insufficiency. This study examined i) the frequency of vitamin D deficiency in patients of both JIA-collectives compared to population controls (KiGGS study), ii) characteristics associated with vitamin D deficiency, and iii) in the ICON cohort associations between 25(OH)D levels, disease activity and the development of uveitis. The statistical evaluation was carried out with the SAS program-package.Results: A high prevalence of vitamin D deficiency (44% ICON, 61% CCSC) was found in both JIA patient groups, but equally in the general population (62% KiGGS). The average vitamin D level was 22.8 ng/ml (ICON); 19.0 ng/ml (CCSC) and 19.1 ng/ml (KiGGS). Vitamin D deficiency was more common in adolescents (≥ 12 years), in migrants and between October and April.In ICON patients there was a significant negative correlation between vitamin D levels and disease activity as well as incidence of uveitis. Patients with vitamin D levels ≥ 28 ng/ml received DMARD therapy less frequently.Summary: Vitamin D deficiency is common in JIA-patients, although not more common than in the population. It seems to have an adverse effect on the course of the disease and the occurrence of uveitis. Further studies should identify which vitamin D supply can contribute to reducing disease activity and extra-articular manifestations in JIA.In view of the available options to prevent vitamin D deficiency, these results are of considerable clinical relevance