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Understanding how diversity is partitioned across the landscape provides perspectives on the environmental processes that have influenced the evolutionary history of organisms. We analyzed spatial demography, historical biogeography, and niche divergence of the western jumping mouse (Zapus princeps) using molecular sequence data from mitochondrial and nuclear DNA recovered from 7 of the 11 subspecies in western North America. Phylogeographic structure within Z. princeps was partitioned across 5 clades (Boreal, Northern Sierra, Southern Rockies, Southern Sierra, and Uinta). Two lineages detected in the Sierra Nevada of California (Northern Sierra and Southern Sierra) were more closely allied to Z. trinotatus than to other lineages of Z. princeps and species distribution models mirror these phylogenetic signatures by detecting wide overlap in niches for Sierran jumping mice and Z. trinotatus as compared to other Z. princeps. Four southern lineages are deeply divergent and limited to disjunct mesic and montane habitats within the xeric southwestern United States, whereas the 5th lineage is widespread, extending from Wyoming to Alaska and reflecting expansion northward following deglaciation, a common pattern in boreal mammals. © 2013 American Society of Mammalogists.

Understanding how diversity is partitioned across the landscape provides perspectives on the environmental processes that have influenced the evolutionary history of organisms. We analyzed spatial demography, historical biogeography, and niche divergence of the western jumping mouse (Zapus princeps) using molecular sequence data from mitochondrial and nuclear DNA recovered from 7 of the 11 subspecies in western North America. Phylogeographic structure within Z. princeps was partitioned across 5 clades (Boreal, Northern Sierra, Southern Rockies, Southern Sierra, and Uinta). Two lineages detected in the Sierra Nevada of California (Northern Sierra and Southern Sierra) were more closely allied to Z. trinotatus than to other lineages of Z. princeps and species distribution models mirror these phylogenetic signatures by detecting wide overlap in niches for Sierran jumping mice and Z. trinotatus as compared to other Z. princeps. Four southern lineages are deeply divergent and limited to disjunct mesic and montane habitats within the xeric southwestern United States, whereas the 5th lineage is widespread, extending from Wyoming to Alaska and reflecting expansion northward following deglaciation, a common pattern in boreal mammals. © 2013 American Society of Mammalogists.

Dirac neutrinos with masses in the MeV range and having "standard model" magnetic moments are known to violate the cosmological 4He bound. We calculate the value of the magnetic dipole moment of Dirac neutrinos in the mass range 5-35 MeV which would allow for consistency with the inferred primordial abundances of 2H, 3He, 4He and 7Li. © 1992.

Dirac neutrinos with masses in the MeV range and having "standard model" magnetic moments are known to violate the cosmological 4He bound. We calculate the value of the magnetic dipole moment of Dirac neutrinos in the mass range 5-35 MeV which would allow for consistency with the inferred primordial abundances of 2H, 3He, 4He and 7Li. © 1992.

We show that considerations of the equilibration of right- and left-handed neutrino seas in the early Universe and the well-known He4 constraint on the number of relativistic degrees of freedom extant at the nucleosynthesis epoch lead to a new limit on the Dirac neutrino mass of 300keV. This constraint would apply to any neutrino so long as it had a purely Dirac mass and a lifetime exceeding the nucleosynthesis time scale. © 1991 The American Physical Society.

The implications of the Z0-width experiment for the number of neutrino flavors taken together with the 4He constraint on the energy density at the nucleosynthesis epoch, can give a limit on the extent to which a right-handed neutrino sea could contribute to the expansion rate of the universe during Big Bang nucleosynthesis. Since the population of the right-handed neutrino sea depends on the neutrino mass we can extract a Dirac neutrino mass limit of mv ≪ 150 keV. This limit could apply to νμ or ντ if they have purely Dirac masses. © 1991.

We show that considerations of the equilibration of right- and left-handed neutrino seas in the early Universe and the well-known He4 constraint on the number of relativistic degrees of freedom extant at the nucleosynthesis epoch lead to a new limit on the Dirac neutrino mass of 300keV. This constraint would apply to any neutrino so long as it had a purely Dirac mass and a lifetime exceeding the nucleosynthesis time scale. © 1991 The American Physical Society.

The most stringent bounds on the individual lepton numbers of the universe arise from considerations of primordial nucleosynthesis. We consider the effect of resonant neutrino flavor oscillations on these limits. In particular, we include the contributions from neutrino-neutrino forward scattering to the effective mass of each neutrino flavor. We find that there can be significant modifications to the neutrino number densities and energy distributions for each flavor over a large range of neutrino vacuum masses and mixing angles. Modifi-cations to the neutrino distributions occurring prior to the nucleosynthesis epoch can substantially alter the previously derived limits on the lepton number for each flavor and its associated degeneracy parameter.

The most stringent bounds on the individual lepton numbers of the universe arise from considerations of primordial nucleosynthesis. We consider the effect of resonant neutrino flavor oscillations on these limits. In particular, we include the contributions from neutrino-neutrino forward scattering to the effective mass of each neutrino flavor. We find that there can be significant modifications to the neutrino number densities and energy distributions for each flavor over a large range of neutrino vacuum masses and mixing angles. Modifi-cations to the neutrino distributions occurring prior to the nucleosynthesis epoch can substantially alter the previously derived limits on the lepton number for each flavor and its associated degeneracy parameter.

The implications of the Z0-width experiment for the number of neutrino flavors taken together with the 4He constraint on the energy density at the nucleosynthesis epoch, can give a limit on the extent to which a right-handed neutrino sea could contribute to the expansion rate of the universe during Big Bang nucleosynthesis. Since the population of the right-handed neutrino sea depends on the neutrino mass we can extract a Dirac neutrino mass limit of mv ≪ 150 keV. This limit could apply to νμ or ντ if they have purely Dirac masses. © 1991.