LHCf Measurements of Very Forward Particles at LHC

The LHC forward experiment (LHCf) is specifically designed for measurements of the very forward ($\eta$$>$8.4) production cross sections of neutral pions and neutrons at Large Hadron Collider (LHC) at CERN. LHCf started data taking in December 2009, when the LHC started to provide stable collisions of protons at $\sqrt{s}$=900\,GeV. Since March 2010, LHC increased the collision energy up to $\sqrt{s}$=7\,TeV. By the time of the symposium, LHCf collected 113k events of high energy showers (corresponding to $\sim$7M inelastic collisions) at $\sqrt{s}$=900\,GeV and $\sim$100M showers ($\sim$14 nb$^{-1}$ of integrated luminosity) at $\sqrt{s}$=7\,TeV. Analysis results with the first limited sample of data demonstrate that LHCf will provide crucial data to improve the interaction models to understand very high-energy cosmic-ray air showers.Comment: Invited talk given at XVI International Symposium on Very High Energy Cosmic Ray Interactions (ISVHECRI 2010), Batavia, IL, USA, 28 June 2 July 2010. 6 pages, 10 figure

Weed Models for Integrated Pest Management of Lettuce

Spanish needle {Bidens pilosa L.) and cheeseweed {Malva parviflora L.) are reservoir hosts of tomato spotted wilt virus (TSWV). Thrips are attracted to their flowers, and the larvae acquire the virus whiie feeding on them. Massive migrations of infected thrips from the reservoir hosts into the lettuce fields have resulted in severe crop losses. In an integrated pest management program, knowing the flowering patterns of Spanish needle and cheeseweed will aid in the prediction of thrips migrations and control the incidence of disease by TSWV. The objective of this study was to deveiop statistical models to predict the time to first flower (T50) and the time to the flower peak of these 2 weed species. Spanish needle plants were observed from the 5-node stage for the opening of the first flower and until the flower peak occurred. Increasing temperature and rainfall shortened the T50 and the time to the flower peak. Weather data were used to develop models to predict T50 and peak flowering time. Growing degree days was included in the analysis using a base temperature of 5 °C. The model to predict T50 was T50 = -0.57(MAXT) - 0.31 (MINT) + 0.05(GDD) + 21.61 where T50 is the time to 50% of the plants flowered (days), MAXT is the average maximum air temperature (°C) from the 5-node stage to T50, MINT is the average minimum air temperature (°C) from the 5-node stage to T50, and GDD is the sum of growing degree days from the 5-node stage to T50. The coefficient of multiple determination (R2) was 0.99 ***. Validation of the model resulted in predicted values that were within 1 day for 2 of 3 locations. The model to predict peak flowering was WKS = -0.46(MAXT) - 0.32(EVAP) + 13.33 where WKS is the number of weeks from the 5-node stage to the flowering peak and EVAP is the summation of evaporation (cm) from the 5-node stage to peak flower. The R2 was 0.82 **. Validation of the model indicated that the model predicted peak flowering to within 1 week of the actual peak time. Cheeseweed plants were observed from the 4-leaf stage for the opening of the first flower and until peak flower. Increasing temperature and rainfall shortened the T50 and time to peak flower. Weather data were used to develop models to predict T50 and peak flowering time. Growing degree days was included in the analysis using a base temperature of 6 °C. The model to predict T50 was T50 = 0.05(GDD) + 7.3 where T50 is the time to 50% of the plants flowered (days), and GDD is the sum of growing degree days from the 4-leaf stage to T50. The R2 was 0.86 ***. Validation of the model showed that it predicted T50 values that were within an average of 4 days from the actual values. The model to predict the time to the flower peak was WKS = -0.5(MAXT) + 0.007(GDD) + 15.6 where WKS is the number of weeks from the 4-leaf stage to the flowering peak, and MAXT is the average air maximum temperature (°C) from the 4-leaf stage to peak flower. The R2 was 0.96 ***. Validation of the model indicated that it predicted the observed peak flowering time. These models can be used to help time control measures to control thrips and TSWV

Air Shower Simulation and Hadronic Interactions

The aim of this report of the Working Group on Hadronic Interactions and Air Shower Simulation is to give an overview of the status of the field, emphasizing open questions and a comparison of relevant results of the different experiments. It is shown that an approximate overall understanding of extensive air showers and the corresponding hadronic interactions has been reached. The simulations provide a qualitative description of the bulk of the air shower observables. Discrepancies are however found when the correlation between measurements of the longitudinal shower profile are compared to that of the lateral particle distributions at ground. The report concludes with a list of important problems that should be addressed to make progress in understanding hadronic interactions and, hence, improve the reliability of air shower simulations.Comment: Working Group report given at UHECR 2012 Symposium, CERN, Feb. 2012. Published in EPJ Web of Conferences 53, 01007 (2013

Resolved 24.5 micron emission from massive young stellar objects

Massive young stellar objects (MYSO) are surrounded by massive dusty envelopes. Our aim is to establish their density structure on scales of ~1000 AU, i.e. a factor 10 increase in angular resolution compared to similar studies performed in the (sub)mm. We have obtained diffraction-limited (0.6") 24.5 micron images of 14 well-known massive star formation regions with Subaru/COMICS. The images reveal the presence of discrete MYSO sources which are resolved on arcsecond scales. For many sources, radiative transfer models are capable of satisfactorily reproducing the observations. They are described by density powerlaw distributions (n(r) ~ r^(-p)) with p = 1.0 +/-0.25. Such distributions are shallower than those found on larger scales probed with single-dish (sub)mm studies. Other sources have density laws that are shallower/steeper than p = 1.0 and there is evidence that these MYSOs are viewed near edge-on or near face-on, respectively. The images also reveal a diffuse component tracing somewhat larger scale structures, particularly visible in the regions S140, AFGL 2136, IRAS 20126+4104, Mon R2, and Cep A. We thus find a flattening of the MYSO envelope density law going from ~10 000 AU down to scales of ~1000 AU. We propose that this may be evidence of rotational support of the envelope (abridged).Comment: 21 pages, accepted for A&

Local Magnetic Turbulence and TeV-PeV Cosmic Ray Anisotropies

In the energy range from ~ 10^12 eV to ~ 10^15 eV, the Galactic cosmic ray flux has anisotropies both on large scales, with an amplitude of the order of 0.1%, and on scales between ~ 10 and ~ 30 degrees, with amplitudes smaller by a factor of a few. With a diffusion coefficient inferred from Galactic cosmic ray chemical abundances, the diffusion approximation predicts a dipolar anisotropy of comparable size, but does not explain the smaller scale anisotropies. We demonstrate here that energy dependent smaller scale anisotropies naturally arise from the local concrete realization of the turbulent magnetic field within the cosmic ray scattering length. We show how such anisotropies could be calculated if the magnetic field structure within a few tens of parsecs from Earth were known.Comment: 5 pages (2 columns), 3 figures. Published in Physical Review Letter