Multi-Component Dark Matter Systems and Their Observation Prospects

Conversions and semi-annihilations of dark matter (DM) particles in addition to the standard DM annihilations are considered in a three-component DM system. We find that the relic abundance of DM can be very sensitive to these non-standard DM annihilation processes, which has been recently found for two-component DM systems. To consider a concrete model of a three-component DM system, we extend the radiative seesaw model of Ma by adding a Majorana fermion \chi and a real scalar boson \phi, to obtain a Z_2 \times Z'_2 DM stabilizing symmetry, where we assume that the DM particles are the inert Higgs boson, \chi and \phi. It is shown how the allowed parameter space, obtained previously in the absence of \chi and \phi, changes. The semi-annihilation process in this model produces monochromatic neutrinos. The observation rate of these monochromatic neutrinos from the Sun at IceCube is estimated. Observations of high energy monochromatic neutrinos from the Sun may indicate a multi-component DM system.Comment: 27 pages, 11 figure

Stop-over and Migration Ecology of the Whimbrel: Fall 2009 Season Report

The whimbrel (Numenius phaeopus) is a large, Holarctic, highly migratory shorebird. The North American race (N.p. hudsonicus) includes two disjunct breeding populations, both of which winter primarily in Central and South America. The western population breeds in Alaska and the Northwest Territories of Canada (Engelmoer and Roselaar 1998). The eastern population breeds south and west of Hudson Bay in Manitoba and Ontario (Skeel and Mallory 1996, Jehl and Smith 1970). The prevailing thought was that the western population followed a Pacific Coast migration route between breeding and wintering areas in Panama and western South America, and that the Hudson Bay population followed an Atlantic Coast migration route to wintering grounds in Northeast South America (Andres et al. 2009, Skeel and Mallory 1996, Morrison and Ross 1989). Both populations are of high conservation concern due to population declines in recent decades (Bart et al. 2007, Morrison et al. 2006, Watts and Truitt in press). Investigations into the migration routes of whimbrels staging in Virginia have shown a previously unknown link between the eastern and western populations as they stop-over in Virginia (Watts et al. 2008). The primary objective of this project is to examine the stop-over and migration strategies of whimbrels, as they relate to the conservation of the species. A total of four 9.5 gram PTT satellite transmitters were deployed during the fall migration season. Average weight for the whimbrels with transmitters was 527.2 grams, or approximately 200 grams over mean winter (lean) weight. Ten digitally coded glue-on radio transmitters were attached to birds. The cumulative data give us insight into stop-over times for whimbrels as they stage on the Eastern Shore of Virginia before migrating to wintering grounds. Satellite and radio transmittered whimbrels departed the Eastern Shore between 31 August and 20 September 2009. Whimbrels arrived on the Eastern Shore in large numbers as early as early to mid-July due to record low temperatures and winter-like conditions on the breeding grounds. Several unusual migration events were observed during the fall season. Twelve flights greater than 1,000km were documented during the fall. These flights took an average of 95 hours to complete. The average distance traveled during these flights was 2,697km. A total of 5 shorter flights on wintering grounds were also documented, with birds moving from initial locations in Dominica, Venezuela, and Guyana into French Guiana, Suriname, and Brazil, the primary wintering grounds for eastern whimbrels (Morrison and Ross 1989). The mean distance traveled on these flights was 597km with the mean time in flight 47.3 hours

Anoxia Tolerance During Vertebrate Development - Insights from Studies on the Annual Killifish Austrofundulus limnaeus

This is chapter 1 from Anoxia -- This book reviews how severe oxygen deprivation affects biological systems - from the molecular to the ecological level. The contributing authors come from diverse regions of the world, which proves the interest in the academic analysis of oxygen deprivation. The diversity in the experimental approach scientists take, in order to understand the influence oxygen deprivation has on living systems, is apparent throughout this book. One of the presented ideas deals with the exploration and examination of the physiological, cellular and genetic characteristics of killifish embryos and nematodes exposed to anoxia. Furthermore, the book includes material on the mechanisms regulating hypoxia and anoxia tolerance and their implications of on human health issues. Finally, new methodologies to examine oxygen deprivation and the impact of human-related activities on oxygen level, within important ecological systems such as Lake Victoria, are presented. There is no doubt that the oxygen molecule is central to every stratum of biological systems

Using Satellite and Radio Telemetry to Examine Stopover and Migration Ecology of the Whimbrel: 2009-2011 Report

The whimbrel (Numenius phaeopus) is a large, Holarctic, highly migratory shorebird. The North American race (N.p. hudsonicus) includes two disjunct breeding populations, both of which winter primarily in Central and South America. The western population breeds in Alaska and the Northwest Territories of Canada (Engelmoer and Roselaar 1998). The eastern population breeds south and west of Hudson Bay in Manitoba and Ontario (Skeel and Mallory 1996, Jehl and Smith 1970). The prevailing idea was that the western population followed a Pacific Coast migration route between breeding and wintering areas in Panama and western South America, and that the Hudson Bay population followed an Atlantic Coast migration route to wintering grounds in Northeast South America (Andres et al. 2009, Skeel and Mallory 1996, Morrison and Ross 1989). Both populations are of high conservation concern due to population declines in recent decades (Bart et al. 2007, Morrison et al. 2006, Watts and Truitt in press). Investigations into the migration routes of whimbrels staging in Virginia have shown a previously unknown link between the eastern and western populations as they stop-over in Virginia (Watts et al. 2008). The primary objective of this project is to examine the stop-over and migration strategies of whimbrels, as they relate to the conservation of the species. A total of 12 9.5 gram PTT satellite transmitters were deployed during the 2009-2010 spring and fall migration seasons. Average weight for the whimbrels with transmitters was 568 ± 53SD grams, or approximately 150-200 grams over mean winter (lean) weight. A total of 67 digitally coded glue-on radio transmitters were attached to birds during these seasons. The cumulative data give us insight into stop-over times for whimbrels as they stage on the Eastern Shore of Virginia before migrating to both breeding and wintering grounds. Satellite and radio transmittered whimbrels departed the Eastern Shore in the spring season between 22 May and 3 June and in the fall season between 11 August and 20 September. Spring birds tend to leave during a short window (CCB/TNC spring whimbrel count unpublished data), whereas fall birds have a much bigger migration window as shown by the wide range of satellite and radio transmitter leave dates. Several unusual migration events were observed during the spring and fall seasons. Twenty flights averaging 2,595 km were documented during the spring seasons. These flights took an average of 81 hours to complete. Twenty-four flights averaging 2,603 km were documented during the fall seasons. These flights took an average of 91hours to complete. A total of 13 shorter flights on breeding grounds were also documented, with birds moving from initial locations in along the Hudson Bay coastline to interior breeding locations. The mean distance traveled on these flights was 435 km with the mean time in flight 44 hours. A total of 17 shorter flights on wintering grounds were documented, with birds moving from initial locations in the Greater and Lesser Antilles, Suriname, and Guyana into French Guiana, Suriname, and Brazil, the primary wintering grounds for the Atlantic population of whimbrels (Morrison and Ross 1989). The mean distance traveled on these flights was 548 km with the mean time in flight 52 hours

An investigation of stopover ecology of the red knot on the Virginia Barrier Island

The Virginia barrier island chain plays a significant role in the life cycle of many of the most vulnerable shorebird species in North America. The large areas of relatively undisturbed beach and marsh habitat available to shorebirds during the migrator

On the Quantitative Impact of the Schechter-Valle Theorem

We evaluate the Schechter-Valle (Black Box) theorem quantitatively by considering the most general Lorentz invariant Lagrangian consisting of point-like operators for neutrinoless double beta decay. It is well known that the Black Box operators induce Majorana neutrino masses at four-loop level. This warrants the statement that an observation of neutrinoless double beta decay guarantees the Majorana nature of neutrinos. We calculate these radiatively generated masses and find that they are many orders of magnitude smaller than the observed neutrino masses and splittings. Thus, some lepton number violating New Physics (which may at tree-level not be related to neutrino masses) may induce Black Box operators which can explain an observed rate of neutrinoless double beta decay. Although these operators guarantee finite Majorana neutrino masses, the smallness of the Black Box contributions implies that other neutrino mass terms (Dirac or Majorana) must exist. If neutrino masses have a significant Majorana contribution then this will become the dominant part of the Black Box operator. However, neutrinos might also be predominantly Dirac particles, while other lepton number violating New Physics dominates neutrinoless double beta decay. Translating an observed rate of neutrinoless double beta decay into neutrino masses would then be completely misleading. Although the principal statement of the Schechter-Valle theorem remains valid, we conclude that the Black Box diagram itself generates radiatively only mass terms which are many orders of magnitude too small to explain neutrino masses. Therefore, other operators must give the leading contributions to neutrino masses, which could be of Dirac or Majorana nature.Comment: 18 pages, 4 figures; v2: minor corrections, reference added, matches journal version; v3: typo corrected, physics result and conclusions unchange

Neutrino-less Double Beta Decay and Particle Physics

We review the particle physics aspects of neutrino-less double beta decay. This process can be mediated by light massive Majorana neutrinos (standard interpretation) or by something else (non-standard interpretations). The physics potential of both interpretations is summarized and the consequences of future measurements or improved limits on the half-life of neutrino-less double beta decay are discussed. We try to cover all proposed alternative realizations of the decay, including light sterile neutrinos, supersymmetric or left-right symmetric theories, Majorons, and other exotic possibilities. Ways to distinguish the mechanisms from one another are discussed. Experimental and nuclear physics aspects are also briefly touched, alternative processes to double beta decay are discussed, and an extensive list of references is provided.Comment: 96 pages, 38 figures. Published versio