109 research outputs found

    Microbunching instability characterization via temporally modulated laser pulses

    Get PDF
    High-brightness electron bunches, such as those generated and accelerated in free-electron lasers (FELs), can develop small-scale structure in the longitudinal phase space. This causes variations in the slice energy spread and current profile of the bunch which then undergo amplification, in an effect known as the microbunching instability. By imposing energy spread modulations on the bunch in the low-energy section of an accelerator, using an undulator and a modulated laser pulse in the center of a dispersive chicane, it is possible to manipulate the bunch longitudinal phase space. This allows for the control and study of the instability in unprecedented detail. We report measurements and analysis of such modulated electron bunches in the 2D spectrotemporal domain at the Fermi FEL, for three different bunch compression schemes. We also perform corresponding simulations of these experiments and show that the codes are indeed able to reproduce the measurements across a wide spectral range. This detailed experimental verification of the ability of codes to capture the essential beam dynamics of the microbunching instability will benefit the design and performance of future FELs

    Microbunching instability characterization via temporally modulated laser pulses

    Get PDF
    High-brightness electron bunches, such as those generated and accelerated in free-electron lasers (FELs), can develop small-scale structure in the longitudinal phase space. This causes variations in the slice energy spread and current profile of the bunch which then undergo amplification, in an effect known as the microbunching instability. By imposing energy spread modulations on the bunch in the low-energy section of an accelerator, using an undulator and a modulated laser pulse in the centre of a dispersive chicane, it is possible tomanipulate the bunch longitudinal phase space. This allows for the control and study of the instability in unprecedented detail. We report measurements and analysis of such modulated electron bunches in the 2Dspectro-temporal domain at the FERMI FEL, for three different bunch compression schemes. We also perform corresponding simulations of these experiments and show that the codes are indeed able to reproduce the measurements across a wide spectral range. This detailed experimental verification of the ability of codes to capture the essential beam dynamics of the microbunching instability will benefit the design and performance of future FELs

    Palynological and chemical volatile components of tipically autumnal honeys of the western Mediterranean

    Full text link
    [EN] Twenty-five samples of autumnal honeys from the western Mediterranean (Mallorca and Eivissa, Balearic Islands) were examined for pollen content (qualitative and quantitative melissopalynological analysis), moisture, electrical conductivity, colour, sensorial qualities and volatile components. Quantitative analysis showed that the honey contained Maurizio's Class II: 64%, Class III: 28%, Class IV: 4% and Class V: 4%. Fifty-four pollen types, with an average number of 16.68 per sample, were identified, belonging to 29 botanical families. Only two taxa (Ceratonia siliqua and Erica multiflora) were found in all samples. Seventeen samples were unifloral (68%) - ten (40%) of C. siliqua, six (24%) of E. multiflora and one (4%) of Hedera helix. All honeys have a low honeydew index (<?0.09%), while the values for electrical conductivity and water content were high. The major honey volatile components are: cis- and trans-linalool oxides (64.2%) and hotrienol (10.4%) for the carob (C. siliqua) and trans-linalool oxide (13.4%), p-menthane-1,8-diol (11.1%), safranal (9.7%), limonene (5,4%), -pinene (3.7%) and oxoisophorone (3.4%) for the winter heather (E. multiflora).The authors would like to extend their gratitude to the Mallorca Rural 'Leader plus' programme and the beekeepers of Mallorca and Eivissa for their support and friendly collaboration. The authors also thank an anonymous reviewer for useful comments and suggestions on an earlier version of the manuscript.Boi, M.; Llorens Molina, JA.; CortĂ©s, L.; LladĂł, G.; Llorens, L. (2013). Palynological and chemical volatile components of tipically autumnal honeys of the western Mediterranean. Grana. 52(2):93-105. doi:10.1080/00173134.2012.744774S93105522Andrade, P. B., Amaral, M. T., Isabel, P., Carvalho, J. C. M. F., Seabra, R. M., & Proença da Cunha, A. (1999). Physicochemical attributes and pollen spectrum of Portuguese heather honeys. Food Chemistry, 66(4), 503-510. doi:10.1016/s0308-8146(99)00100-4Anklam, E. (1998). A review of the analytical methods to determine the geographical and botanical origin of honey. Food Chemistry, 63(4), 549-562. doi:10.1016/s0308-8146(98)00057-0Bosch, J., Del Pino, F. G., Ramoneda, J., & Retana, J. (1996). FRUITING PHENOLOGY AND FRUIT SET OF CAROB, CERATONIA SILIQUA L. (CESALPINACEAE). Israel Journal of Plant Sciences, 44(4), 359-368. doi:10.1080/07929978.1996.10676657Bouseta, A., Collin, S., & Dufour, J.-P. (1992). Characteristic aroma profiles of unifloral honeys obtained with a dynamic headspace GC-MS system. Journal of Apicultural Research, 31(2), 96-109. doi:10.1080/00218839.1992.11101268Cajka, T., Hajslova, J., Pudil, F., & Riddellova, K. (2009). Traceability of honey origin based on volatiles pattern processing by artificial neural networks. Journal of Chromatography A, 1216(9), 1458-1462. doi:10.1016/j.chroma.2008.12.066Castro-VĂĄzquez, L., DĂ­az-Maroto, M. C., GonzĂĄlez-Viñas, M. A., & PĂ©rez-Coello, M. S. (2009). Differentiation of monofloral citrus, rosemary, eucalyptus, lavender, thyme and heather honeys based on volatile composition and sensory descriptive analysis. Food Chemistry, 112(4), 1022-1030. doi:10.1016/j.foodchem.2008.06.036Conti, M. E., Stripeikis, J., Campanella, L., Cucina, D., & Tudino, M. B. (2007). Characterization of Italian honeys (Marche Region) on the basis of their mineral content and some typical quality parameters. Chemistry Central Journal, 1(1). doi:10.1186/1752-153x-1-14CustĂłdio, L., Serra, H., Nogueira, J. M. F., Gonçalves, S., & Romano, A. (2006). Analysis of the Volatiles Emitted by Whole Flowers and Isolated Flower Organs of the Carob Tree Using HS-SPME-GC/MS. Journal of Chemical Ecology, 32(5), 929-942. doi:10.1007/s10886-006-9044-9Cuevas-Glory, L., Ortiz-VĂĄzquez, E., Pino, J. A., & Sauri-Duch, E. (2012). Floral classification of Yucatan Peninsula honeys by PCA & HS-SPME/GC-MS of volatile compounds. International Journal of Food Science & Technology, 47(7), 1378-1383. doi:10.1111/j.1365-2621.2012.02983.xDe BolĂČs, O., & Molinier, R. (1984). Vegetation of the Pityusic Islands. Biogeography and Ecology of the Pityusic Islands, 185-221. doi:10.1007/978-94-009-6539-3_9De Maria, C. A. B., & Moreira, R. F. A. (2003). Compostos volĂĄteis em mĂ©is florais. QuĂ­mica Nova, 26(1), 90-96. doi:10.1590/s0100-40422003000100016Guyot, C., Scheirman, V., & Collin, S. (1999). Floral origin markers of heather honeys: Calluna vulgaris and Erica arborea. Food Chemistry, 64(1), 3-11. doi:10.1016/s0308-8146(98)00122-8Herrera, J. (1988). Pollination Relationships in Southern Spanish Mediterranean Shrublands. The Journal of Ecology, 76(1), 274. doi:10.2307/2260469Jerković, I., & Marijanović, Z. (2010). Volatile Composition Screening of Salix spp. Nectar Honey: Benzenecarboxylic Acids, Norisoprenoids, Terpenes, and Others. Chemistry & Biodiversity, 7(9), 2309-2325. doi:10.1002/cbdv.201000021Jones, G. D., & Bryant, Jr, V. M. (2004). The use of ETOH for the dilution of honey. Grana, 43(3), 174-182. doi:10.1080/00173130410019497Kummerow, J. (1983). Comparative Phenology of Mediterranean-Type Plant Communities. Ecological Studies, 300-317. doi:10.1007/978-3-642-68935-2_17La‐Serna Ramos, I. E., & GÓmez Ferreras, C. (2006). Pollen and sensorial characterization of different honeys from El Hierro (Canary Islands). Grana, 45(2), 146-159. doi:10.1080/00173130600578658Del Carmen Llasat, M., Ramis, C., & Barrantes, J. (1996). The meteorology of high‐intensity rainfall events over the west Mediterranean region. Remote Sensing Reviews, 14(1-3), 51-90. doi:10.1080/02757259609532313Louveaux, J., Maurizio, A., & Vorwohl, G. (1978). Methods of Melissopalynology. Bee World, 59(4), 139-157. doi:10.1080/0005772x.1978.11097714Martins, R. C., Lopes, V. V., ValentĂŁo, P., Carvalho, J. C. M. F., Isabel, P., Amaral, M. T., 
 Silva, B. M. (2008). Relevant principal component analysis applied to the characterisation of Portuguese heather honey. Natural Product Research, 22(17), 1560-1582. doi:10.1080/14786410701825004Melliou, E., & Chinou, I. (2011). Chemical constituents of selected unifloral Greek bee-honeys with antimicrobial activity. Food Chemistry, 129(2), 284-290. doi:10.1016/j.foodchem.2011.04.047Pendleton, M. (2006). Descriptions of melissopalynological methods involving centrifugation should include data for calculating Relative Centrifugal Force (RCF) or should express data in units of RCF or gravities (g). Grana, 45(1), 71-72. doi:10.1080/00173130500520479PĂ©rez, R. A., SĂĄnchez-Brunete, C., Calvo, R. M., & Tadeo, J. L. (2002). Analysis of Volatiles from Spanish Honeys by Solid-Phase Microextraction and Gas Chromatography−Mass Spectrometry. Journal of Agricultural and Food Chemistry, 50(9), 2633-2637. doi:10.1021/jf011551rPersano Oddo, L., Piana, L., Bogdanov, S., Bentabol, A., Gotsiou, P., Kerkvliet, J., 
 von der Ohe, K. (2004). Botanical species giving unifloral honey in Europe. Apidologie, 35(Suppl. 1), S82-S93. doi:10.1051/apido:2004045Persano Oddo, L., & Piro, R. (2004). Main European unifloral honeys: descriptive sheets. Apidologie, 35(Suppl. 1), S38-S81. doi:10.1051/apido:2004049Piana, M. L., Persano Oddo, L., Bentabol, A., Bruneau, E., Bogdanov, S., & Guyot Declerck, C. (2004). Sensory analysis applied to honey: state of the art. Apidologie, 35(Suppl. 1), S26-S37. doi:10.1051/apido:2004048Piasenzotto, L., Gracco, L., & Conte, L. (2003). Solid phase microextraction (SPME) applied to honey quality control. Journal of the Science of Food and Agriculture, 83(10), 1037-1044. doi:10.1002/jsfa.1502Radovic, B. S., Careri, M., Mangia, A., Musci, M., Gerboles, M., & Anklam, E. (2001). Contribution of dynamic headspace GC–MS analysis of aroma compounds to authenticity testing of honey. Food Chemistry, 72(4), 511-520. doi:10.1016/s0308-8146(00)00263-6RAMÓN-LACA, L., & MABBERLEY, D. J. (2004). The ecological status of the carob-tree (Ceratonia siliqua, Leguminosae) in the Mediterranean. Botanical Journal of the Linnean Society, 144(4), 431-436. doi:10.1111/j.1095-8339.2003.00254.xRetana, J., Ramoneda, J., Garcia Del Pino, F., & Bosch, J. (1994). Flowering phenology of carob,Ceratonia siliquaL. (Cesalpinaceae). Journal of Horticultural Science, 69(1), 97-103. doi:10.1080/14620316.1994.11515254Ricciardelli d’Albore, G. & Vorwohl, G. (1979). Mieles monoflorales en el MediterrĂĄneo documentado con ayuda del anĂĄlisis microscĂłpico de mieles. Actas de XXVII Congreso Internacional de Apicultura, Athens, Greece, 14–20 September 1979, 201–208.Pilar de Sá‐Otero, M., Armesto‐Baztan, S., & DÍaz‐Losada, E. (2006). A study of variation in the pollen spectra of honeys sampled from the Baixa Limia‐Serra do XurĂ©s Nature Reserve in north‐west Spain. Grana, 45(2), 137-145. doi:10.1080/00173130600708537Seijo, M. C., Jato, M. V., Aira, M. J., & Iglesias, I. (1997). Unifloral honeys of Galicia (north-west Spain). Journal of Apicultural Research, 36(3-4), 133-140. doi:10.1080/00218839.1997.11100939Terrab, A., Diez, M. J., & Heredia, F. J. (2003). Palynological, physico-chemical and colour characterization of Moroccan honeys: III. Other unifloral honey types. International Journal of Food Science and Technology, 38(4), 395-402. doi:10.1046/j.1365-2621.2003.00713.xTERRAB, A., PONTES, A., HEREDIA, F. J., & DÍEZ, M. J. (2004). A preliminary palynological characterization of Spanish thyme honeys. Botanical Journal of the Linnean Society, 146(3), 323-330. doi:10.1111/j.1095-8339.2004.00335.xTerrab, A., ValdĂ©s, B., & Josefa DĂ­ez, M. (2003). Pollen analysis of honeys from the Mamora forest region (NW Morocco). Grana, 42(1), 47-54. doi:10.1080/00173130310008580Thompson, J. D. (2005). Plant Evolution in the Mediterranean. doi:10.1093/acprof:oso/9780198515340.001.0001Von Der Ohe, W., Persano Oddo, L., Piana, M. L., Morlot, M., & Martin, P. (2004). Harmonized methods of melissopalynology. Apidologie, 35(Suppl. 1), S18-S25. doi:10.1051/apido:2004050VORWOHL, G. (1964). DIE BEZIEHUNGEN ZWISCHEN DER ELEKTRISCHEN LEITFÄHIGKEIT DER HONIGE UND IHRER TRACHTMÄSSIGEN HERKUNFT. Annales de l’Abeille, 7(4), 301-309. doi:10.1051/apido:19640403Vorwohl, G. (1967). The microscopic analysis of honey, a comparison of its methods with those of the other branches of palynology. Review of Palaeobotany and Palynology, 3(1-4), 287-290. doi:10.1016/0034-6667(67)90061-

    DNMT3L Is a Regulator of X Chromosome Compaction and Post-Meiotic Gene Transcription

    Get PDF
    Previous studies on the epigenetic regulator DNA methyltransferase 3-Like (DNMT3L), have demonstrated it is an essential regulator of paternal imprinting and early male meiosis. Dnmt3L is also a paternal effect gene, i.e., wild type offspring of heterozygous mutant sires display abnormal phenotypes suggesting the inheritance of aberrant epigenetic marks on the paternal chromosomes. In order to reveal the mechanisms underlying these paternal effects, we have assessed X chromosome meiotic compaction, XY chromosome aneuploidy rates and global transcription in meiotic and haploid germ cells from male mice heterozygous for Dnmt3L. XY bodies from Dnmt3L heterozygous males were significantly longer than those from wild types, and were associated with a three-fold increase in XY bearing sperm. Loss of a Dnmt3L allele resulted in deregulated expression of a large number of both X-linked and autosomal genes within meiotic cells, but more prominently in haploid germ cells. Data demonstrate that similar to embryonic stem cells, DNMT3L is involved in an auto-regulatory loop in germ cells wherein the loss of a Dnmt3L allele resulted in increased transcription from the remaining wild type allele. In contrast, however, within round spermatids, this auto-regulatory loop incorporated the alternative non-coding alternative transcripts. Consistent with the mRNA data, we have localized DNMT3L within spermatids and sperm and shown that the loss of a Dnmt3L allele results in a decreased DNMT3L content within sperm. These data demonstrate previously unrecognised roles for DNMT3L in late meiosis and in the transcriptional regulation of meiotic and post-meiotic germ cells. These data provide a potential mechanism for some cases of human Klinefelter's and Turner's syndromes

    Machine layout and performance

    Get PDF
    The Large Hadron Collider (LHC) is one of the largest scientific instruments ever built. Since opening up a new energy frontier for exploration in 2010, it has gathered a global user community of about 7,000 scientists working in fundamental particle physics and the physics of hadronic matter at extreme temperature and density. To sustain and extend its discovery potential, the LHC will need a major upgrade in the 2020s. This will increase its luminosity (rate of collisions) by a factor of five beyond the original design value and the integrated luminosity (total collisions created) by a factor ten. The LHC is already a highly complex and exquisitely optimised machine so this upgrade must be carefully conceived and will require about ten years to implement. The new configuration, known as High Luminosity LHC (HL-LHC), will rely on a number of key innovations that push accelerator technology beyond its present limits. Among these are cutting-edge 11-12 tesla superconducting magnets, compact superconducting cavities for beam rotation with ultra-precise phase control, new technology and physical processes for beam collimation and 300 metre-long high-power superconducting links with negligible energy dissipation. The present document describes the technologies and components that will be used to realise the project and is intended to serve as the basis for the detailed engineering design of HL-LHC

    The SysteMHC Atlas project.

    Get PDF
    Mass spectrometry (MS)-based immunopeptidomics investigates the repertoire of peptides presented at the cell surface by major histocompatibility complex (MHC) molecules. The broad clinical relevance of MHC-associated peptides, e.g. in precision medicine, provides a strong rationale for the large-scale generation of immunopeptidomic datasets and recent developments in MS-based peptide analysis technologies now support the generation of the required data. Importantly, the availability of diverse immunopeptidomic datasets has resulted in an increasing need to standardize, store and exchange this type of data to enable better collaborations among researchers, to advance the field more efficiently and to establish quality measures required for the meaningful comparison of datasets. Here we present the SysteMHC Atlas (https://systemhcatlas.org), a public database that aims at collecting, organizing, sharing, visualizing and exploring immunopeptidomic data generated by MS. The Atlas includes raw mass spectrometer output files collected from several laboratories around the globe, a catalog of context-specific datasets of MHC class I and class II peptides, standardized MHC allele-specific peptide spectral libraries consisting of consensus spectra calculated from repeat measurements of the same peptide sequence, and links to other proteomics and immunology databases. The SysteMHC Atlas project was created and will be further expanded using a uniform and open computational pipeline that controls the quality of peptide identifications and peptide annotations. Thus, the SysteMHC Atlas disseminates quality controlled immunopeptidomic information to the public domain and serves as a community resource toward the generation of a high-quality comprehensive map of the human immunopeptidome and the support of consistent measurement of immunopeptidomic sample cohorts

    Muon (g-2) Technical Design Report

    Get PDF
    The Muon (g-2) Experiment, E989 at Fermilab, will measure the muon anomalous magnetic moment a factor-of-four more precisely than was done in E821 at the Brookhaven National Laboratory AGS. The E821 result appears to be greater than the Standard-Model prediction by more than three standard deviations. When combined with expected improvement in the Standard-Model hadronic contributions, E989 should be able to determine definitively whether or not the E821 result is evidence for physics beyond the Standard Model. After a review of the physics motivation and the basic technique, which will use the muon storage ring built at BNL and now relocated to Fermilab, the design of the new experiment is presented. This document was created in partial fulfillment of the requirements necessary to obtain DOE CD-2/3 approval
    • 

    corecore