Tests of Higgs Boson Couplings at a mu+mu- Collider

We investigate the potential of a muon collider for testing the presence of anomalous Higgs boson couplings. We consider the case of a light (less than $160 GeV$) Higgs boson and study the effects on the Higgs branching ratios and total width, which could be induced by the non standard couplings created by a class of dim=6 $SU(3)\times SU(2)\times U(1)$ gauge invariant operators satisfying the constraints imposed by the present and future hadronic and $e^-e^+$ colliders. For each operator we give the minimal value of the $\mu^+\mu^-$ integrated luminosity needed for the muon collider ($\mu C$) to improve these constraints. Depending on the operator and the Higgs mass, this minimal $\mu C$ luminosity lies between $0.1 fb^{-1}$ and $100 fb^{-1}$.Comment: 18 pages and 4 figures; version to be published in Phys. Rev.D. e-mail: [email protected]

Comparison of Deep-Water Viromes from the Atlantic Ocean and the Mediterranean Sea

The aim of this study was to compare the composition of two deep-sea viral communities obtained from the RomancheFracture Zone in the Atlantic Ocean (collected at 5200 m depth) and the southwest Mediterranean Sea (from 2400 m depth)using a pyro-sequencing approach. The results are based on 18.7% and 6.9% of the sequences obtained from the AtlanticOcean and the Mediterranean Sea, respectively, with hits to genomes in the non-redundant viral RefSeq database. Theidentifiable richness and relative abundance in both viromes were dominated by archaeal and bacterial viruses accountingfor 92.3% of the relative abundance in the Atlantic Ocean and for 83.6% in the Mediterranean Sea. Despite characteristicdifferences in hydrographic features between the sampling sites in the Atlantic Ocean and the Mediterranean Sea, 440 virusgenomes were found in both viromes. An additional 431 virus genomes were identified in the Atlantic Ocean and 75 virusgenomes were only found in the Mediterranean Sea. The results indicate that the rather contrasting deep-sea environmentsof the Atlantic Ocean and the Mediterranean Sea share a common core set of virus types constituting the majority of bothvirus communities in terms of relative abundance (Atlantic Ocean: 81.4%; Mediterranean Sea: 88.7%)

Mapeamento de solos através do caráter espectral, da rede de drenagem e da vegetação

This study puts together three different methodologies that utilize Remote Sensing Techniques for the study of soils. The soils of the selected area were studied by their spectra parameters and analysed through satellite images processed in an appropriate equipment. The drainage indices were correlated to their respective soils. The well known relationship between types of cerrado vegetation and associated soils were also studied. For each situation a soil map was prepared; those maps showed a reasonable relationship with the ground truth. Wen these informations were put together in a single map, the relationship with the reference soil map was highly significant, showing the applicability of the methodology.O presente trabalho reuniu três metodologias conhecidas para o estudo de solos, todas associadas às técnicas de sensoriamento remoto. Para uma mesma área, os solos foram relacionados aos seus parâmetros espectrais obtidos digitalmente de imagens de satélite; os índices de drenagem da área foram também relacionados aos respectivos solos; a conhecida relação entre tipos de cerrado e respectivos solos suporte foi também estudada. Para cada situação foi preparado um mapa de solos, que se aproximava do mapa já existente. Quando as informações de tais mapas foram agregadas em um único mapa, a aproximação com o mapa de controle foi altamente satisfatória evidenciando a aplicabilidade da metodologia

Optical triangulations of curved spaces

Not only do curved spaces fascinate scientists and non-scientists, but they are also at the heart of general relativity and modern theories of quantum gravity. Optical systems can provide models for the wave and quantum behavior of curved spaces. Here we show how to construct optical systems that simulate triangulations of 3D curved spaces, for example, the curved 3D surface of a 4D hypersphere. Our work offers a new approach to the optical simulation of curved spaces, and has the potential to lead to new ways of thinking about physics in curved spaces and simulating otherwise inaccessible phenomena in non-Euclidean geometries

Are Causality Violations Undesirable?

Causality violations are typically seen as unrealistic and undesirable features of a physical model. The following points out three reasons why causality violations, which Bonnor and Steadman identified even in solutions to the Einstein equation referring to ordinary laboratory situations, are not necessarily undesirable. First, a space-time in which every causal curve can be extended into a closed causal curve is singularity free--a necessary property of a globally applicable physical theory. Second, a causality-violating space-time exhibits a nontrivial topology--no closed timelike curve (CTC) can be homotopic among CTCs to a point, or that point would not be causally well behaved--and nontrivial topology has been explored as a model of particles. Finally, if every causal curve in a given space-time passes through an event horizon, a property which can be called "causal censorship", then that space-time with event horizons excised would still be causally well behaved.Comment: Accepted in October 2008 by Foundations of Physics. Latex2e, 6 pages, no figures. Presented at a seminar at the Universidad Nacional Autonoma de Mexico. Version 2 was co-winner of the QMUL CTC Essay Priz

Biologische bestrijding van weekhuidmijten in bromelia

Tarsonemidae (weekhuidmijten) zijn belangrijke plaagorganismen in de teelt van bromelia-achtigen. In Nederland werden ze voor het eerst aangetroffen in 1989 op Neoregelia carolinae en geïdentificeerd door de PD als Steneotarsonemus ananas, de ananasmijt. Weekhuidmijten zijn zeer kleine plantzuigende mijtjes van slechts 0,2 mm groot. Ze kunnen verschillende soorten schade aan de Bromelia’s veroorzaken: necrotische plekken aan de bladeren en jonge plantdelen, bruin-rode bladstrepen en misvorming van de bloeiwijze. De chemische bestrijding is lastig, mede door het verdwijnen van langwerkende acariciden. Het onderzoek waar in dit rapport verslag wordt gemaakt is uitgevoerd tussen 2008 en 2010. Het is opgestart mede naar aanleiding van oriënterende proeven (Messelink en Van Holstein-Saj, 2007) met potentiële biologische bestrijders van deze plaag. Doel van dit vervolg-onderzoek was om basiskennis over de biologie van ananasmijten op Bromelia uit te breiden, wat van belang is voor het ontwikkelen van een goede bestrijdingsstrategie. Gedurende het onderzoek zijn monsters afkomstig van praktijkbedrijven (meestal vermeerderingsbedrijven, maar ook productiebedrijven) onderzocht. Op bromelia’s met “ananasmijtsymptomen” werden verschillende soorten weekhuidmijten (familieTarsonemidae) gevonden. Het betrof zowel planten-eters (Steneotarsonemus-soorten) als onschadelijke schimmel-eters (Tarsonemus-soorten). Binnen het geslacht Steneotarsonemus konden twee soorten worden onderscheiden. Beide zijn waarschijnlijk species novae (niet eerder beschreven soorten). De echte ananasmijt, Steneotarsonemus ananas, werd niet aangetroffen. Weekhuidmijten veroorzaken verkleuringen en misvormingen, die vaak pas geruime tijd na de aantasting zichtbaar worden. De mijten zelf kunnen inmiddels al weer vertrokken zijn naar geschiktere delen van de waardplant (groeipunten). Het onderzoek naar besmettingsbronnen en verspreidingswijze van de weekhuidmijten heeft zich vooral gericht op vermeerderingsbedrijven. Oudere bromelia’s lijken minder gevoelig voor aantasting, maar blijven wel een mogelijke besmettingsbron Steneotarsonemus is in hoge mate gebonden aan levend plantmateriaal. Grond en fust zijn geen waarschijnlijke besmettingsbronnen. De voortplantingssnelheid is in principe zeer hoog (extreem korte generatieduur), maar de actieve verspreiding van plant naar plant is traag. Planten moeten elkaar daartoe raken; verspreiding via grond of tafel is niet waarschijnlijk. Passieve verspreiding is mogelijk via mensen, verplaatsen van planten en volgens de literatuur ook via vliegende insekten. Of dit laatste in de praktijk een rol speelt, is niet bekend. Bodemgebonden roofmijten bleken zeer algemeen op de vermeerderingsbedrijven. Naast de gebruikelijke soorten identificeerden we Lasioseius fimetorum en Armascirus taurus. Volgens onze laboratoriumobservaties zijn weekhuidmijten geen geschikte prooi (want te klein?) voor grotere roofmijten zoals Hypoaspis. Wel geschikt zijn sommige kleinere roofmijtsoorten van de familie Phytoseiidae. Lasioseius fimetorum, qua grootte een “middenklasser”, krijgt het voordeel van de twijfel. Van de momenteel commercieel beschikbare roofmijten geldt Amblyseius barkeri als de meest geschikte predator van weekhuidmijten. Op bedrijven waar roofmijten waren uitgezet, werden de telers geïnterviewd over de toegepaste strategie en werden populatiebemonsteringen van de roofmijten uitgevoerd. Wij slaagden er niet in halfwas bromelia’s langdurig met Phytoseiidae (Amblyseius swirskii en Amblyseius barkeri) te koloniseren

Generalized Brans-Dicke cosmology in the presence of matter and dark energy

We study the Generalized Brans-Dicke cosmology in the presence of matter and dark energy. Of particular interest for a constant Brans-Dicke parameter, the de Sitter space has also been investigated.Comment: 9 page

Search for the Proton Decay Mode proton to neutrino K+ in Soudan 2

We have searched for the proton decay mode proton to neutrino K+ using the one-kiloton Soudan 2 high resolution calorimeter. Contained events obtained from a 3.56 kiloton-year fiducial exposure through June 1997 are examined for occurrence of a visible K+ track which decays at rest into mu+ nu or pi+ pi0. We found one candidate event consistent with background, yielding a limit, tau/B > 4.3 10^{31} years at 90% CL with no background subtraction.Comment: 13 pages, Latex, 3 tables and 3 figures, Accepted by Physics Letters

Heavy Residue Formation in 20 MeV/nucleon 197Au + 90Zr collisions

The yields and velocity distributions of heavy residues and fission fragments from the reaction of 20 MeV/nucleon 197Au + 90Zr have been measured using the MSU A1200 fragment separator. A bimodal distribution of residues is observed, with one group, resulting from peripheral collisions, having fragment mass numbers A=160-200, while the other group, resulting from ``hard'' collisions, has A=120-160. This latter group of residues can be distinguished from fission fragments by their lower velocities. A model combining deep-inelastic transfer and incomplete fusion for the primary interaction stage and a statistical evaporation code for the deexcitation stage has been used to describe the properties of the product distributions.Comment: 19 pages, 6 figures, preprint submitted to Nucl. Phys.