Search for solar hadronic axions produced by a bremsstrahlung-like process

We have searched for hadronic axions which may be produced in the Sun by a bremsstrahlung-like process, and observed in the HPGe detector by an axioelectric effect. A conservative upper limit on the hadronic axion mass m_a < 334 eV at 95% C.L. is obtained. Our experimental approach is based on the axion-electron coupling and it does not include the axion-nucleon coupling, which suffers from the large uncertainties related to the estimation of the flavor-singlet axial-vector matrix element.Comment: 9 pages, 3 figures; version to appear in PL

Seasonal Sea Ice Conditions Affect Caribou Crossing Areas Around Qikiqtaq, Nunavut: Uqsuqtuurmiut Knowledge Guides Ice Chart Analysis

Though polar ecologists consider sea ice primarily as a habitat for marine mammals, caribou use sea ice to complete their reproductive cycles, to access areas with preferred climatic and vegetation conditions, and to avoid predators seasonally and sporadically. Building on previous caribou research in Uqsuqtuuq (Gjoa Haven, Nunavut), we explored the connections between caribou and sea ice phenology in 5 community-identified caribou crossing areas around Qikiqtaq (King William Island). We defined freeze-up and breakup based on Uqsuqtuurmiut (people of Uqsuqtuuq) knowledge of caribou habitat requirements, to orient our analysis to the complex and multifaceted hazards that caribou can encounter while moving through their dynamic and unpredictable sea ice habitat. We investigated the reliability of caribou sea ice habitat surrounding Qikiqtaq, prioritizing key transitional periods with intensified caribou movement. We use regional ice charts produced by the Canadian Ice Service (CIS) and held workshops with Uqsuqtuurmiut to understand how sea ice phenology and caribou mobility have changed over time. The high spatial and temporal variability of sea ice phenology around Qikiqtaq facilitates caribou moving across sea ice should they need to respond to seasonal or unpredictable changes in ecological conditions or anthropogenic disturbance. Therefore, these localized sea ice conditions may increase caribou resiliency to changes or extreme events by providing alternative options for movement across the sea ice. We encourage others to consider the needs of wildlife sea ice users when assessing or providing ice information. Bien que les écologistes polaires considèrent que la glace de mer est principalement un habitat de mammifères marins, les caribous s’en servent pour leurs cycles de reproduction, pour accéder à des lieux dont les conditions climatiques et la végétation conviennent à leurs préférences et pour éviter les prédateurs, en fonction des saisons et de manière sporadique. En nous appuyant sur des recherches antérieures sur les caribous à Uqsuqtuuq (Gjoa Haven, Nunavut), nous avons exploré les liens entre le caribou et la phénologie de cinq points de franchissement des caribous dans la région de Qikiqtaq (île King William), tels que déterminés par la communauté. Nous avons défini l’englacement et la débâcle en nous fondant sur les connaissances des Uqsuqtuurmiut (le peuple d’Uqsuqtuuq) concernant les besoins du caribou en matière d’habitat afin d’éclairer notre analyse des dangers complexes et multidimensionnels auxquels les caribous peuvent faire face quand ils se déplacent dans leur habitat de glace de mer dynamique et imprévisible. Nous avons étudié la fiabilité de l’habitat de glace de mer du caribou dans les alentours de Qikiqtaq, en accordant une attention particulière aux périodes de transition pendant lesquelles les déplacements des caribous sont plus intenses. Nous avons utilisé les cartes des glaces régionales produites par le Service canadien des glaces (SCG) et organisé des ateliers avec les Uqsuqtuurmiut pour comprendre comment la phénologie de la glace de mer et la mobilité des caribous ont évolué au fil du temps. La grande variabilité spatiale et temporelle de la phénologie de la glace de mer des environs de Qikiqtaq facilite le déplacement des caribous sur la glace de mer s’ils devaient réagir aux changements saisonniers et imprévisibles des conditions écologiques et de la perturbation anthropique. Par conséquent, ces conditions de glace de mer localisées peuvent avoir pour effet d’augmenter la résilience du caribou aux changements ou aux événements extrêmes, car elles présentent des options de rechange en matière de déplacements sur la glace de mer. Nous incitons d’autres personnes à considérer les besoins de la faune utilisant la glace de mer lorsqu’elles doivent évaluer ou fournir de l’information sur la glace de mer.

Nuclear excitation by the inelastic photoelectric effect

The possibility of a nucleus being excited during an interaction involving an incident photon, a bound orbital electron, and the nucleus has been investigated. In this inelastic photoelectric effect the angular distribution of the ejected photoelectrons has been calculated and the dependence of the total cross section on the photon energy and the nuclear excitation energy has been investigated. NUCLEAR REACTIONS Calculated probability of nuclear excitation in interaction involving incident photon and bound atomic electron. Dependence of cr on Z, E~, and photoelectron emission angle 8 studied

Sexual dimorphism in striatal dopaminergic responses promotes monogamy in social songbirds

In many songbird species, males sing to attract females and repel rivals. How can gregarious, non-territorial songbirds such as zebra finches, where females have access to numerous males, sustain monogamy? We found that the dopaminergic reward circuitry of zebra finches can simultaneously promote social cohesion and breeding boundaries. Surprisingly, in unmated males but not in females, striatal dopamine neurotransmission was elevated after hearing songs. Behaviorally too, unmated males but not females persistently exchanged mild punishments in return for songs. Song reinforcement diminished when dopamine receptors were blocked. In females, we observed song reinforcement exclusively to the mate’s song, although their striatal dopamine neurotransmission was only slightly elevated. These findings suggest that song-triggered dopaminergic activation serves a dual function in social songbirds: as low-threshold social reinforcement in males and as ultra-selective sexual reinforcement in females. Co-evolution of sexually dimorphic reinforcement systems can explain the coexistence of gregariousness and monogamy

Heat flow of the Earth and resonant capture of solar 57-Fe axions

In a very conservative approach, supposing that total heat flow of the Earth is exclusively due to resonant capture inside the Earth of axions, emitted by 57-Fe nuclei on Sun, we obtain limit on mass of hadronic axion: m_a<1.8 keV. Taking into account release of heat from decays of 40-K, 232-Th, 238-U inside the Earth, this estimation could be improved to the value: m_a<1.6 keV. Both the values are less restrictive than limits set in devoted experiments to search for 57-Fe axions (m_a<216-745 eV), but are much better than limits obtained in experiments with 83-Kr (m_a<5.5 keV) and 7-Li (m_a<13.9-32 keV).Comment: 8 page

Exact Self-consistent Particle-like Solutions to the Equations of Nonlinear Scalar Electrodynamics in General Relativity

Exact self-consistent particle-like solutions with spherical and/or cylindrical symmetry to the equations governing the interacting system of scalar, electromagnetic and gravitational fields have been obtained. As a particular case it is shown that the equations of motion admit a special kind of solutions with sharp boundary known as droplets. For these solutions, the physical fields vanish and the space-time is flat outside of the critical sphere or cylinder. Therefore, the mass and the electric charge of these configurations are zero.Comment: 17 pages, Submitted to the International Journal of Theoretical Physic

Double Spin Asymmetries A_NN and A_SS at sqrt{s}=200 GeV in Polarized Proton-Proton Elastic Scattering at RHIC

We present the first measurements of the double spin asymmetries A_NN and A_SS at sqrt{s}=200 GeV, obtained by the pp2pp experiment using polarized proton beams at the Relativistic Heavy Ion Collider (RHIC). The data were collected in the four momentum transfer t range 0.01<|t|<0.03 (GeV/c)^2. The measured asymmetries, which are consistent with zero, allow us to estimate upper limits on the double helicity-flip amplitudes phi_2 and phi_4 at small t as well as on the difference Delta(sigma_T) between the total cross sections for transversely polarized protons with antiparallel or parallel spin orientations.Comment: 13 pages with 3 figures. Final version accepted by Phys. Lett.