Meter-scale spark X-ray spectrumstatistics

X-ray emission by sparks implies bremsstrahlung from a population of energetic electrons, but the details of this process remain a mystery. We present detailed statistical analysis of X-ray spectra detected by multiple detectors during sparks produced by 1 MV negative high-voltage pulses with 1 $\mu$s risetime. With over 900 shots, we statistically analyze the signals, assuming that the distribution of spark X-ray fluence behaves as a power law and that the energy spectrum of X-rays detectable after traversing $\sim$2 m of air and a thin aluminum shield is exponential. We then determine the parameters of those distributions by fitting cumulative distribution functions to the observations. The fit results match the observations very well if the mean of the exponential X-ray energy distribution is 86 $\pm$ 7 keV and the spark X-ray fluence power law distribution has index -1.29 $\pm$ 0.04 and spans at least 3 orders of magnitude in fluence

Hemostatic Agents for the Management of Bleeding Risk Associated with Oral Anticoagulant Therapy Following Tooth Extraction: A Systematic Review

The occurrence of bleeding following dental extraction is a relatively common complication. A history of therapy with oral anticoagulants represents a major favoring factor, both in patients treated with vitamin K-antagonists (especially warfarin) and with direct oral anticoagulants (DOACs). Several local hemostatic measures can be applied to limit the bleeding risk in these patients. The aim of this systematic review is to evaluate what measures can be adopted to limit the bleeding risk following dental extractions in patients treated with oral anticoagulants. A literature search was performed, and 116 articles were retrieved. Titles and abstract analyses excluded 91 articles, and three more articles were excluded following full-text analysis. The systematic review was performed on 22 articles. Among the included articles, 20 studies reported on patients treated with warfarin, and two studies on patients treated with DOACs. The agents employed included local intra-alveolar agents, tranexamic acid, and PRF. The included studies were all at moderate/high risk of bias. Moreover, limited evidence is available on hemostasis in patients treated with DOACs. The available evidence hinders stating the superiority of one agent over the others. Further research is advised to increase the level of evidence of the application of hemostatic agents in patients treated with oral anticoagulants

Relativistic electrons from sparks in the laboratory

Discharge experiments were carried out at the Eindhoven University of Technology in 2013. The experimental setup was designed to search for electrons produced in meter-scale sparks using a 1 MV Marx generator. Negative voltage was applied to the high voltage (HV) electrode. Five thin (1 mm) plastic detectors (5 $\rm cm^2$ each) were distributed in various configurations close to the spark gap. Earlier studies have shown (for HV negative) that X-rays are produced when a cloud of streamers is developed 30-60 cm from the negative electrode. This indicates that the electrons producing the X-rays are also accelerated at this location, that could be in the strong electric field from counterstreamers of opposite polarity. Comparing our measurements with modeling results, we find that $\sim$300 keV electrons produced about 30-60 cm from the negative electrode are the most likely source of our measurements. A statistical analysis of expected detection of photon bursts by these fiber detectors indicates that only 20%-45% of the detected bursts could be from soft ($\sim$10 keV) photons, which further supports that the majority of detected bursts are produced by relativistic electrons

Investigation of SNPs in the ATP1A2, CA3 and DECR1 genes mapped to porcine chromosome 4: analysis in groups of pigs divergent for meat production and quality traits

STUDIO DI TRE GENI (ATP1A2, CA3E DECR1) LOCALIZZATI SUL CROMOSOMA SUINO 4: ANALISIDELLE FREQUENZE ALLELICHE DI SNP IN SUINI ESTREMI PER ALCUNI CARATTERI PRODUTTIVITre geni (ATPase, Na+/K+transporting, \u3b12(+) polypeptide, ATP1A2; carbonic anhydrase III, CA3; 2,4-die-noyl CoA reductase 1, mitochondrial, DECR1), isolati da una libreria a cDNA ottenuta da muscolo scheletri-co di suino, sono stati scelti per questo studio sulla base del ruolo fisiologico della proteina codificata in pro-cessi cellulari e metabolici collegabili in modo diretto o indiretto con alcuni caratteri produttivi. La scelta dei tre geni \ue8 stata anche basata sulla loro localizzazione sul cromosoma 4 dove diversi QTL per caratteri pro-duttivi sono gi\ue0 stati identificati.Nella regione 3\u2019 non tradotta del gene CA3\ue8 stato identificato, mediante analisi SSCP, un polimorfismo bial-lelico. Il sequenziamento dei due alleli ha permesso di identificare una nuova mutazione puntiforme, che \ue8stata successivamente analizzata mediante PCR-RFLP. Per questo gene \ue8 stato effettuato il mappaggiogenetico sul cromosoma 4 mediante l\u2019analisi della mutazione nei campioni delle famiglie di riferimento delprogetto europeo di mappaggio del genoma suino (PiGMaP). Utilizzando il polimorfismo PCR-RFLP del geneATP1A2, gi\ue0 decritto in un precedente lavoro come SSCP, sono state tipizzate diverse famiglie di riferimen-to PiGMaP ed \ue8 stato confermato il mappaggio genetico di ATP1A2. Utilizzando queste informazioni e quel-le gi\ue0 disponibili per DECR1, per la prima volta, \ue8 stata ottenuta una mappa di linkage del cromosoma 4che comprende tutti e tre i geni analizzati. Il mappaggio genetico dei tre geni \ue8 stato anche confermatomediante tipizzazione di un pannello di ibridi di cellule irradiate (IMpRH 7000 rad).Le frequenze alleliche delle mutazioni identificate nei tre loci sono state studiate in 11 razze suine (LargeWhite Italiana, Landrace Italiana, Duroc Italiana, Landrace Belga, Hampshire, Pi\ue9train, Meishan, CintaSenese, Casertana, Calabrese and Nero Siciliano) per un totale di 272 animali. Inoltre, come approccio ini-ziale per poi scegliere i geni da analizzare in futuri studi di associazione, abbiamo confrontato le frequenzealleliche di mutazioni puntiformi per questi tre loci in gruppi di suini di razza Large White Italiana e DurocItaliana, analizzando animali con valori degli indici genetici estremi e divergenti per alcuni caratteri produt-tivi (accrescimento, spessore lardo dorsale, tagli magri e grasso intermuscolare visibile). Per il gene CA3 \ue8stata osservata una differenza nella distribuzione delle frequenze alleliche (P< 0,05) per i due caratteri taglimagri (nella razza Large White Italiana) e grasso intermusculare visibile (nella razza Duroc Italiana). Per ilgene DECR1, differenze significative sono state osservate per il carattere grasso intermuscolare visibile. Ilgene ATP1A2, che mappa vicino al locus FAT1, non ha presentato differenze statisticamente significativenelle frequenze tra i gruppi estremi per i caratteri oggetto di studio. Analizzando il livello di linkage disequi-librium(LD) tra i tre loci, \ue8 stato evidenziato un elevato livello di LD (D\u2019= 0,967; P< 0,0001) tra i geni CA3e DECR1, solo nella popolazione Duroc Italiana. Questi primi risultati pongono le basi per ulteriori studi perverificare se i geni CA3e DECR1sono associati con i caratteri oggetto di selezione nel suino pesante.Three genes (ATPase, Na+/K+ transporting, \u3b1 2(+) polypeptide, ATP1A2; carbonic anhydrase III, CA3; 2,4-dienoyl CoA reductase 1, mitochondrial, DECR1), isolated from a porcine skeletal muscle cDNA library and mapped on porcine chromosome 4 (SSC4), were investigated. A new single nucleotide polymorphism (SNP) was identified in the 3\u2019-untranslated region of the CA3 gene and used to genetically map this locus on SSC4 together with the ATP1A2 and DECR1 loci for which SNPs were already reported. Allele frequencies of the three loci were reported for 11 pig breeds (Italian Large White, Italian Landrace, Italian Duroc, Belgian Landrace, Hampshire, Pi\uf9train, Meishan, Cinta Senese, Casertana, Calabrese and Nero Siciliano). Radiation hybrid mapping of these genes confirmed the linkage mapping results as well as mapping information reported by other authors. Then, the SNPs identified in the ATP1A2, CA3 and DECR1 genes were genotyped in Italian Large White and Italian Duroc animal groups with extreme and divergent estimated breeding value for several production traits. For CA3 significant differences in allele frequencies (P< 0.05) were observed between the extreme groups of pigs for the lean cuts (Italian Large White) and visible intermuscular fat (Italian Duroc) traits. For DECR1, a significant difference in allele frequencies was observed only for the visible intermuscular fat trait. ATP1A2, which maps close to the FAT1 locus, did not show any significant difference. A very high linkage disequilibrium (D\u2019= 0.967; P< 0.0001) was identified between CA3 and DECR1 in the Italian Duroc population. Further investigations are needed to evaluate the effect of CA3 and DECR1 on the considered trait

Placing Location-Based Narratives in Context Through a Narrator and Visual Markers

Location-based services, narratives and interactive experiences have a substantial tradition in human–computer interaction. Building on this background, we report the iterative design process, prototyping and evaluation of Seven Stories, a location-based narrative experience. The design includes two novel features that aim to link the user experience more closely to its physical context: visual markers scanning and a narrator. We have evaluated Seven Stories with two studies. Study 1, with 12 participants, was conducted using qualitative methods to assess the overall user experience. Study 2, with 21 participants, was conducted using quantitative methods, to evaluate the role of the markers and narrator as specific design features. Our contribution is to illustrate, through both qualitative and quantitative findings, how these two novel features influence the user experience, and what implications they have for design

New experimental limits on the alpha decays of lead isotopes

For the first time a PbWO4 crystal was grown using ancient Roman lead and it was run as a cryogenic detector. Thanks to the simultaneous and independent read-out of heat and scintillation light, the detector was able to discriminate beta/gamma interactions with respect to alpha particles down to low energies. New more stringent limits on the alpha decays of the lead isotopes are presented. In particular a limit of T_{1/2} > 1.4*10^20 y at a 90% C.L. was evaluated for the alpha decay of 204Pb to 200Hg

Material screening and selection for XENON100

Results of the extensive radioactivity screening campaign to identify materials for the construction of XENON100 are reported. This Dark Matter search experiment is operated underground at Laboratori Nazionali del Gran Sasso (LNGS), Italy. Several ultra sensitive High Purity Germanium detectors (HPGe) have been used for gamma ray spectrometry. Mass spectrometry has been applied for a few low mass plastic samples. Detailed tables with the radioactive contaminations of all screened samples are presented, together with the implications for XENON100.Comment: 8 pages, 1 figur