Correlation of cosmic-ray intensity and solar activity

The present International Geophysical Year was chosen to include the most likely period of maximum activity of the sun. It is probably too early to tell whether or not the maximum of the current cycle has yet been reached, but it is already certain that the yearly average of the Zurich sunspot numbers for 1957 is much higher than ever before observed.(1) It is therefore of interest to see what has been the effect on cosmic rays

Correlation of cosmic-ray ionization measurements at high altitudes, at sea level, and neutron intensities at mountain tops

Although fluctuations in cosmic rays have been measured at sea level and high altitudes for a number of years, no serious attempt seems to have been made to correlate the two. As a result of a rather long series of balloon flights in the summer of 1951 it now becomes possible to correlate ionization measurements at high and low altitudes. Recent neutron intensity measurements during the same period by Simpson et al. permit a further comparison with this component. There seems to be a good correlation, during this period of observation, between the fluctuations as measured in (1) the ionization at 70,000 ft over North Dakota, (2) the meson component at Cheltenham, Maryland, (3) the meson component at the geomagnetic equator, and (4) the neutron component at mountain tops in Colorado and New Mexico

A description of nesting behaviors, including factors impacting nest site selection, in black‐and‐white ruffed lemurs (Varecia variegata)

Nest site selection is at once fundamental to reproduction and a poorly understood component of many organisms’ reproductive investment. This study investigates the nesting behaviors of black-and-white ruffed lemurs, Varecia variegata, a litter-bearing primate from the southeastern rainforests of Madagascar. Using a combination of behavioral, geospatial, and demographic data, I test the hypotheses that environmental and social cues influence nest site selection and that these decisions ultimately impact maternal reproductive success. Gestating females built multiple large nests throughout their territories. Of these, females used only a fraction of the originally constructed nests, as well as several parking locations as infants aged. Nest construction was best predicted by environmental cues, including the size of the nesting tree and density of feeding trees within a 75 m radius of the nest, whereas nest use depended largely on the size and average distance to feeding trees within that same area. Microhabitat characteristics were unrelated to whether females built or used nests. Although unrelated to nest site selection, social cues, specifically the average distance to conspecifics’ nest and park sites, were related to maternal reproductive success; mothers whose litters were parked in closer proximity to others’ nests experienced higher infant survival than those whose nests were more isolated. This is likely because nesting proximity facilitated communal crèche use by neighboring females. Together, these results suggest a complex pattern of nesting behaviors that involves females strategically building nests in areas with high potential resource abundance, using nests in areas according to their realized productivity, and communally rearing infants within a network of nests distributed throughout the larger communal territory

The T2K ND280 Off-Axis Pi-Zero Detector

The Pi-Zero detector (P{\O}D) is one of the subdetectors that makes up the off-axis near detector for the Tokai-to-Kamioka (T2K) long baseline neutrino experiment. The primary goal for the P{\O}D is to measure the relevant cross sections for neutrino interactions that generate pi-zero's, especially the cross section for neutral current pi-zero interactions, which are one of the dominant sources of background to the electron neutrino appearance signal in T2K. The P{\O}D is composed of layers of plastic scintillator alternating with water bags and brass sheets or lead sheets and is one of the first detectors to use Multi-Pixel Photon Counters (MPPCs) on a large scale.Comment: 17 pages, submitted to NIM

Transport and Acceleration of Energetic Charged Particles near an Oblique Shock

We have developed a numerical simulation code that treats the transport and acceleration of charged particles crossing an idealized oblique, non-relativistic shock within the framework of pitch angle transport using a finite-difference method. We consider two applications: 1) to study the steady-state acceleration of energetic particles at an oblique shock, and 2) to explain observed precursors of Forbush decreases of galactic cosmic rays before the arrival of an interplanetary shock induced by solar activity. For the former, we find that there is a jump in the particle intensity at the shock, which is stronger for more oblique shocks. Detailed pitch angle distributions are also presented. The simple model of a Forbush decrease explains the key features of observed precursors, an enhanced diurnal anisotropy extending several mean free paths upstream of the shock and a depletion of particles in a narrow loss cone at ~0.1 mean free path from the shock. Such precursors have practical applications for space weather prediction.Comment: 20 pages + 12 figures, aas2pp4.sty included, to appear in Astrophys. J. (vol. 515, no. 2, April 20, 1999

Energy Flow in the Hadronic Final State of Diffractive and Non-Diffractive Deep-Inelastic Scattering at HERA

An investigation of the hadronic final state in diffractive and non--diffractive deep--inelastic electron--proton scattering at HERA is presented, where diffractive data are selected experimentally by demanding a large gap in pseudo --rapidity around the proton remnant direction. The transverse energy flow in the hadronic final state is evaluated using a set of estimators which quantify topological properties. Using available Monte Carlo QCD calculations, it is demonstrated that the final state in diffractive DIS exhibits the features expected if the interaction is interpreted as the scattering of an electron off a current quark with associated effects of perturbative QCD. A model in which deep--inelastic diffraction is taken to be the exchange of a pomeron with partonic structure is found to reproduce the measurements well. Models for deep--inelastic $ep$ scattering, in which a sizeable diffractive contribution is present because of non--perturbative effects in the production of the hadronic final state, reproduce the general tendencies of the data but in all give a worse description.Comment: 22 pages, latex, 6 Figures appended as uuencoded fil

Saudi international students’ perceptions of their transition to the UK and the impact of social media

In their transition to a new country, international students often feel lost, anxious or stressed. Saudi students in the UK in particular may face further challenges due to the cultural, social and religious differences that they experience. There is a lot of evidence that social media play a crucial role in this experience. By interviewing 12 Saudi students from different cities in the UK, the aim of this study is to investigate how they perceive their transition to the UK and how social media is involved. The analysis indicates that Saudi students’ perceptions of transition tend to fall in to one of two markedly different camps. Some students see transition as an opportunity to detach themselves from their home country and to engage with the new society. Those students turn to social media as a tool allowing them to build bridges with the new society. Other students feel less enthusiastic to make a full engagement with the UK society. Those students find social media as a good tool to maintain connections and links with family and friends in their home country