Variação sazonal na riqueza e na abundância de pequenos mamíferos, na estrutura da floresta e na disponibilidade de artrópodes em fragmentos florestais no Mato Grosso, Brasil

We captured small mammals in eight forest fragments (43 a 1.411 ha.) during the dry and wet seasons, in southwest Mato Grosso, Brazil, and investigated the variation in small mammal richness and abundance, as well as in forest structure variables (litter volume and canopy openness) and arthropod availability, between the two seasons. Sampling was carried out during the wet season between 2002 and 2003 and in the dry season of 2003. In each fragment, we used Sherman, Tomahawk, snap, and pitfall traps during 10 consecutive days per season, totaling 17,600 trap x nights. In total, we obtained 379 captures of 20 species, seven of marsupials and 13 of rodents. Overall capture success was 2.2% (1.6% during the wet season and 2.7% during the dry season). Total richness, richness of rodents, richness of marsupials, total abundance and abundance of rodents did not varied significantly between seasons. However, marsupial abundance was significantly lower in the dry season, when rainfall is high. Litter volume was significantly higher during the dry season, while arthropod availability was significantly higher during the wet season. Therefore, higher food availability during the wet season may have made trap baits less attractive. In general, the observed variations between dry and wet seasons are in accordance with patterns described in other studies

Long-term measurements of cosmic ray neutrons by means of a Bonner spectrometer at mountain altitudes - first results.

A Bonner multi-sphere spectrometer has been installed in 2005 at the Environmental Research Station 'Schneefernerhaus' (2660 m above sea level) on the Zugspitze mountain, Germany, to measure the energy spectrum of cosmic-ray neutrons at high altitudes continuously. The system can be used to investigate small temporal variations in the cosmic radiation intensity. For example, measurements were done during periods of 2 Forbush decreases of the cosmic radiation intensity in July and September 2005, respectively. The results were compared with those obtained by using neutron monitors, and neutron fluence spectra measured during these events are presented and discussed

GEANT4 transport calculations for neutrons and photons below 15 MeV.

Neutron transport calculations are needed in many fields of radiation protection and medical physics. Neutron transport is often simulated with a Monte Carlo code, which allows the calculation of neutron dose distributions in different geometries, for example in voxel phantoms. So far little information is available about neutron transport below 15 MeV in tissue-like matter performed with the Monte Carlo code GEANT4. Therefore, we compared GEANT4 results of the ambient dose equivalent for neutron energies from 10 meV to 15 MeV with MCNP results and values published in ICRU 57. The GEANT4 code was found to be appropriate to calculate neutron and photon dose at energies below 15 MeV correctly. Furthermore, a method how to include a dose-assessment factor into the calculation was developed and tested

Measurements of secondary neutrons from cosmic radiation with a Bonner sphere spectrometer at 79A degrees N.

Air crew members and airline passengers are continuously exposed to cosmic radiation during their flights. Particles ejected by the sun during so-called solar particle events (SPEs) in periods of high solar activity can contribute to this exposure. In rare cases the dose from a single SPE might even exceed the annual dose limit of 1 mSv above which dose monitoring of air crews is legally required in Germany. Measurements performed by means of neutron monitors have already shown that the relative intensity of secondary neutrons from cosmic radiation is enhanced during an SPE, particularly at regions close to the magnetic poles of the Earth where shielding of the cosmic radiation by the geomagnetic field is low. Here we describe a Bonner sphere spectrometer installed at the Koldewey station at 79A degrees N, i.e. about 1,000 km from the geographic North pole, which is designed to provide first experimental data on the time-dependent energy spectrum of neutrons produced in the atmosphere during an SPE. This will be important to calculate doses from these neutrons to air crew members. The system is described in detail and first results are shown that were obtained during quiet periods of sun activity

FAITH-BASED ECONOMIC DEVELOPMENT

This article identifies factors that appear to contribute to the economic development activities of faith-based institutions. Based on in-depth interviews with churches in Detroit, it concludes that size and revenue of concretion, theology of the head clergy, active initiative by the head pastor or other religious leader, and location in a census tract with residents with lower educational attainment are important determinants of activities. Churches with primarily African American congregations appear to be more active in financing economic development. Denominations of the church appear to have little effect, and deficits in size and resources can be balanced by other attributes. Copyright 2000 by The Policy Studies Organization.