Superconducting Superstructure for the TESLA Collider

We discuss the new layout of a cavity chain (superstructure) allowing, we hope, significant cost reduction of the RF system of both linacs of the TESLA linear collider. The proposed scheme increases the fill factor and thus makes an effective gradient of an accelerator higher. We present mainly computations we have performed up to now and which encouraged us to order the copper model of the scheme, still keeping in mind that experiments with a beam will be necessary to prove if the proposed solution can be used for the acceleration.Comment: 11 page

Functional roles and redundancy of demersal Barents Sea fish: Ecological implications of environmental change

When facing environmental change and intensified anthropogenic impact on marine ecosystems, extensive knowledge of how these systems are functioning is required in order to manage them properly. However, in high-latitude ecosystems, where climate change is expected to have substantial ecological impact, the ecosystem functions of biological species have received little attention, partly due to the limited biological knowledge of Arctic species. Functional traits address the ecosystem functions of member species, allowing the functionality of communities to be characterised and the degree of functional redundancy to be assessed. Ecosystems with higher functional redundancy are expected to be less affected by species loss, and therefore less sensitive to disturbance. Here we highlight and compare typical functional characteristics of Arctic and boreal fish in the Barents Sea and address the consequences of a community-wide reorganization driven by climate warming on functional redundancy and characterization. Based on trait and fish community composition data, we assessed functional redundancy of the Barents Sea fish community for the period 2004–2012, a period during which this northern region was characterized by rapidly warming water masses and declining sea ice coverage. We identified six functional groups, with distinct spatial distributions, that collectively provide a functional characterization of Barents Sea fish. The functional groups displayed different prevalence in boreal and Arctic water masses. Some functional groups displayed a spatial expansion towards the northeast during the study period, whereas other groups showed a general decline in functional redundancy. Presently, the observed patterns of functional redundancy would seem to provide sufficient scope for buffering against local loss in functional diversity only for the more speciose functional groups. Furthermore, the observed functional reconfiguration may affect future ecosystem functioning in the area. In a period of rapid environmental change, monitoring programs integrating functional traits will help inform management on ecosystem functioning and vulnerability.publishedVersio

Progress on a spherical TPC for low energy neutrino detection

The new concept of the spherical TPC aims at relatively large target masses with low threshold and background, keeping an extremely simple and robust operation. Such a device would open the way to detect the neutrino-nucleus interaction, which, although a standard process, remains undetected due to the low energy of the neutrino-induced nuclear recoils. The progress in the development of the fist 1 m$^3$ prototype at Saclay is presented. Other physics goals of such a device could include supernova detection, low energy neutrino oscillations and study of non-standard properties of the neutrino, among others.Comment: 3 pages, talk given at the 9th Workshop on Topics in Astroparticle and Underground Physics, Zaragoza, September 10-1

Observation of Markarian 421 in TeV Gamma Rays Over a 14-Year Time Span

The variability of the blazar Markarian 421 in TeV gamma rays over a 14-year time period has been explored with theWhipple 10 m telescope. It is shown that the dynamic range of its flux variations is large and similar to that in X-rays. A correlation between the X-ray and TeV energy bands is observed during some bright flares and when the complete data sets are binned on long timescales. The main database consists of 878.4 hours of observation with theWhipple telescope, spread over 783 nights. The peak energy response of the telescope was 400 GeV with 20% uncertainty. This is the largest database of any TeV-emitting active galactic nucleus (AGN) and hence was used to explore the variability profile of Markarian 421. The time-averaged flux from Markarian 421 over this period was 0.446+/-0.008 Crab flux units. The flux exceeded 10 Crab flux units on three separate occasions. For the 2000-2001 season the average flux reached 1.86 Crab units, while in the 1996-1997 season the average flux was only 0.23 Crab units

Search for a Correlation Between Very-High-Energy Gamma Rays and Giant Radio Pulses in the Crab Pulsar

We present the results of a joint observational campaign between the Green Bank radio telescope and the VERITAS gamma-ray telescope, which searched for a correlation between the emission of very-high-energy (VHE) gamma rays (E γ \u3e 150 GeV) and giant radio pulses (GRPs) from the Crab pulsar at 8.9 GHz. A total of 15,366 GRPs were recorded during 11.6 hr of simultaneous observations, which were made across four nights in 2008 December and in 2009 November and December. We searched for an enhancement of the pulsed gamma-ray emission within time windows placed around the arrival time of the GRP events. In total, eight different time windows with durations ranging from 0.033 ms to 72 s were positioned at three different locations relative to the GRP to search for enhanced gamma-ray emission which lagged, led, or was concurrent with, the GRP event. Furthermore, we performed separate searches on main pulse GRPs and interpulse GRPs and on the most energetic GRPs in our data sample. No significant enhancement of pulsed VHE emission was found in any of the preformed searches. We set upper limits of 5-10 times the average VHE flux of the Crab pulsar on the flux simultaneous with interpulse GRPs on single-rotation-period timescales. On ~8 s timescales around interpulse GRPs, we set an upper limit of 2-3 times the average VHE flux. Within the framework of recent models for pulsed VHE emission from the Crab pulsar, the expected VHE-GRP emission correlations are below the derived limits

Productivity of pigeon pea and maize rotation system in Balaka District, Southern Malawi

In Malawi, some parts of the country, such as Balaka District in Southern Malawi, are particularly prone to erratic rains with poor soil productivity. In the 2015/2016 rainy season some learning centres (LCs) focusing on pigeon-pea (Cajanus cajan) – maize (Zea mays L) rotations were established in four sections of Ulongwe Agriculture Extension Planning Area (EPA) in Balaka District to enhance soil fertility, nutrition and income diversification for increased resilience to production under erratic rain condition. Up to 132 plots of pigeon were established in 2005/2016 season. Of these 44 fields were sampled for yield, biomass, plant stand and 32 sites for soil data. In the second season of 2016/17, a maize fertilizer response trial with five rates of NPKS (0, 23:21:0+4S, 46:21:0+4S, 69:21:0+4S, and 92:21:0+4S) was super-imposed in the 44 fields, where farmers incorporated pigeon pea residues, a parallel study conducted in a nearby, adjacent field. In the first season, rainfall was low and erratic. Three dry spells (>10 non-rainy days) were recorded in two of four rain gauge stations, and two dry spells in one station. The soil test results showed low P, K and N status. Pigeon pea plant stand was low, with an average of 2.22 plants m-2 compared to an expected 4.44 plants m-2. Grain yields and stover weights were quite variable with a mean of 442 and 1698 kg/ha, respectively. In the second season maize yields grown in both old pigeon pea or continuous maize plots gave a linear response to fertilizer. The gains from pigeon rotation averaged 620, 308, 496 and -1072 for Chibwana Nsamala, Hindahinda, Mulambe and Chitseko sections respectively. The highest recorded yield was 4049 kg/ha from Hindahinda

A Measurement of the Spatial Distribution of Diffuse TeV Gamma Ray Emission from the Galactic Plane with Milagro

Diffuse $\gamma$-ray emission produced by the interaction of cosmic-ray particles with matter and radiation in the Galaxy can be used to probe the distribution of cosmic rays and their sources in different regions of the Galaxy. With its large field of view and long observation time, the Milagro Gamma Ray Observatory is an ideal instrument for surveying large regions of the Northern Hemisphere sky and for detecting diffuse $\gamma$-ray emission at very high energies. Here, the spatial distribution and the flux of the diffuse $\gamma$-ray emission in the TeV energy range with a median energy of 15 TeV for Galactic longitudes between 30$^\circ$ and 110$^\circ$ and between 136$^\circ$ and 216$^\circ$ and for Galactic latitudes between -10$^\circ$ and 10$^\circ$ are determined. The measured fluxes are consistent with predictions of the GALPROP model everywhere except for the Cygnus region ($l\in[65^\circ,85^\circ]$). For the Cygnus region, the flux is twice the predicted value. This excess can be explained by the presence of active cosmic ray sources accelerating hadrons which interact with the local dense interstellar medium and produce gamma rays through pion decay.Comment: 15 pages, 3 figures, accepted by Ap

Productivity and profitability on groundnut (Arachis hypogaea L) and maize (Zea mays L) in a semi-arid area of southern Malawi

In many parts of Malawi, including Balaka district in Southern Malawi, are prone to erratic rains with poor soil productivity and famer practices. A research and outreach project was initiated in October 2015 to establish learning centres (LCs) of groundnut: maize rotations as an entry point to diversify nutrition and income base of smallholder farmers, while building up on soil fertility for increased resilience to production under climatic variation. Some 132 plots of groundnut were established in 2015/2016 in four sections of Ulongwe Extension Planning Area (EPA) in Balaka district. Of these, 44 fields were sampled for yield, biomass, plant stand and soils data. In the second season of 2016/2017, a maize fertilizer response trial (five rates of NP2O5K2O; 0, 23:21:0+4S, 46:21:0+4S, 69:21:0+4S, and 92:21:0+4S) was super-imposed in plots where farmers incorporated groundnut residues, in comparison with continuous maize from adjacent own field. In the first season, rainfall was below average and erratic, with 10-day dry spells recorded in two of four recording stations. The soils were generally poor, with test values below threshold for many variables including organic matter, nitrogen and phosphorus. Groundnut average yields and standard deviation were 754 (±186) kg/ha, respectively. Plant stands were poor, with up to 24% of the 46 LCs attaining ≤50% of targeted plant stand of 8.88 plants m-2. Poor plant stand is suggested as a major contributor to low yields. Results from the 2016/2017 fertilizer response trials showed linear response of maize to fertilizer application. Yields ranged from an average of 1.47 t/ha without fertilizer application to 4.0 t/ha at 92:21:0+4S. It is concluded that the poor soil fertility, low field plant densities, and dry spells are the main causes of low yields. Gross margins were positive for groundnut yield of 1,000 kg/ha and fertilizer rates on maize of 46:23:0+4S and above

Investigating the TeV Morphology of MGRO J1908+06 with VERITAS

We report on deep observations of the extended TeV gamma-ray source MGRO J1908+06 made with the VERITAS very high energy (VHE) gamma-ray observatory. Previously, the TeV emission has been attributed to the pulsar wind nebula (PWN) of the Fermi-LAT pulsar PSR J1907+0602. We detect MGRO J1908+06 at a significance level of 14 standard deviations (14 sigma) and measure a photon index of 2.20 +/- 0.10_stat +/- 0.20_sys. The TeV emission is extended, covering the region near PSR J1907+0602 and also extending towards SNR G40.5--0.5. When fitted with a 2-dimensional Gaussian, the intrinsic extension has a standard deviation of sigma_src = 0.44 +/- 0.02 degrees. In contrast to other TeV PWNe of similar age in which the TeV spectrum softens with distance from the pulsar, the TeV spectrum measured near the pulsar location is consistent with that measured at a position near the rim of G40.5--0.5, 0.33 degrees away.Comment: To appear in ApJ, 8 page

Discovery of Localized Regions of Excess 10-TeV Cosmic Rays

An analysis of 7 years of Milagro data performed on a 10-degree angular scale has found two localized regions of excess of unknown origin with greater than 12 sigma significance. Both regions are inconsistent with gamma-ray emission with high confidence. One of the regions has a different energy spectrum than the isotropic cosmic-ray flux at a level of 4.6 sigma, and it is consistent with hard spectrum protons with an exponential cutoff, with the most significant excess at ~10 TeV. Potential causes of these excesses are explored, but no compelling explanations are found.Comment: Submitted to PhysRevLet