alpha-nucleus potentials for the neutron-deficient p nuclei

alpha-nucleus potentials are one important ingredient for the understanding of the nucleosynthesis of heavy neutron-deficient p nuclei in the astrophysical gamma-process where these p nuclei are produced by a series of (gamma,n), (gamma,p), and (gamma,alpha) reactions. I present an improved alpha-nucleus potential at the astrophysically relevant sub-Coulomb energies which is derived from the analysis of alpha decay data and from a previously established systematic behavior of double-folding potentials.Comment: 6 pages, 3 figures, accepted for publication in Phys. Rev.

Evidence of different climatic adaptation strategies in humans and non-human primates

Abstract: To understand human evolution it is critical to clarify which adaptations enabled our colonisation of novel ecological niches. For any species climate is a fundamental source of environmental stress during range expansion. Mammalian climatic adaptations include changes in size and shape reflected in skeletal dimensions and humans fit general primate ecogeographic patterns. It remains unclear however, whether there are also comparable amounts of adaptation in humans, which has implications for understanding the relative importance of biological/behavioural mechanisms in human evolution. We compare cranial variation between prehistoric human populations from throughout Japan and ecologically comparable groups of macaques. We compare amounts of intraspecific variation and covariation between cranial shape and ecological variables. Given equal rates and sufficient time for adaptation for both groups, human conservation of non-human primate adaptation should result in comparable variation and patterns of covariation in both species. In fact, we find similar amounts of intraspecific variation in both species, but no covariation between shape and climate in humans, contrasting with strong covariation in macaques. The lack of covariation in humans may suggest a disconnect in climatic adaptation strategies from other primates. We suggest this is due to the importance of human behavioural adaptations, which act as a buffer from climatic stress and were likely key to our evolutionary success

Four-particle condensate in strongly coupled fermion systems

Four-particle correlations in fermion systems at finite temperatures are investigated with special attention to the formation of a condensate. Instead of the instability of the normal state with respect to the onset of pairing described by the Gorkov equation, a new equation is obtained which describes the onset of quartetting. Within a model calculation for symmetric nuclear matter, we find that below a critical density, the four-particle condensation (alpha-like quartetting) is favored over deuteron condensation (triplet pairing). This pairing-quartetting competition is expected to be a general feature of interacting fermion systems, such as the excition-biexciton system in excited semiconductors. Possible experimental consequences are pointed out.Comment: LaTeX, 11 pages, 2 figures, uses psfig.sty (included), to be published in Phys. Rev. Lett., tentatively scheduled for 13 April 1998 (Volume 80, Number 15

Does Migration Make You Happy?:A Longitudinal Study of Internal Migration and Subjective Well-Being

The authors acknowledge financial support from the Economic and Social Research Council (ESRC) (RES-625-28-0001). This project is part of the ESRC Centre for Population Change (CPC). Financial support from the Marie Curie programme under the European Union's Seventh Framework Programme (FP/2007-2013) / Career Integration Grant n. PCIG10-GA-2011-303728 (CIG Grant NBHCHOICE, Neighbourhood choice, neighbourhood sorting, and neighbourhood effects).The majority of quantitative studies on the consequences of internal migration focus almost exclusively on the labour-market outcomes and the material well-being of migrants. We investigate whether individuals who migrate within the UK become happier after the move than they were before, and whether the effect is permanent or transient. Using life-satisfaction responses from twelve waves of the British Household Panel Survey and employing a fixed-effects model, we derive a temporal pattern of migrants’ subjective well-being around the time of the migration event. Our findings make an original contribution by revealing that, on average, migration is preceded by a period when individuals experience a significant decline in happiness for a variety of reasons, including changes in personal living arrangements. Migration itself causes a boost in happiness, and brings people back to their initial levels. The research contributes, therefore, to advancing an understanding of migration in relation to set-point theory. Perhaps surprisingly, long-distance migrants are at least as happy as short-distance migrants despite the higher social and psychological costs involved. The findings of this paper add to the pressure to retheorize migration within a conceptual framework that accounts for social well-being from a life-course perspective.PostprintPeer reviewe

Quantum integrable multi atom matter-radiation models with and without rotating wave approximation

New integrable multi-atom matter-radiation models with and without rotating wave approximation (RWA) are constructed and exactly solved through algebraic Bethe ansatz. The models with RWA are generated through ancestor model approach in an unified way. The rational case yields the standard type of matter-radiaton models, while the trigonometric case corresponds to their q-deformations. The models without RWA are obtained from the elliptic case at the Gaudin and high spin limit.Comment: 9 pages, no figure, talk presented in int. conf. NEEDS04 (Gallipoli, Italy, July 2004

Angle resolved photoelectron spectroscopy of two-color XUV-NIR ionization with polarization control

Electron emission caused by extreme ultraviolet (XUV) radiation in the presence of a strong near infrared (NIR) field leads to multiphoton interactions that depend on several parameters. Here, a comprehensive study of the influence of the angle between the polarization directions of the NIR and XUV fields on the two-color angle-resolved photoelectron spectra of He and Ne is presented. The resulting photoelectron angular distribution strongly depends on the orientation of the NIR polarization plane with respect to that of the XUV field. The prevailing influence of the intense NIR field over the angular emission characteristics for He(1s) and Ne(2p) ionization lines is shown. The underlying processes are modeled in the frame of the strong field approximation (SFA) which shows very consistent agreement with the experiment reaffirming the power of the SFA for multicolor-multiphoton ionization in this regime

Hybrid solar and coal-fired steam power plant with air preheating using a centrifugal solid particle receiver

Coal power stations have been hybridised with concentrated solar thermal (CST) fields which producefeedwater or with turbine bleed steam (TBS) heating from directlinear Fresnel to steam technology. This paper assesses solar hybridisation of boiler based steam power plants, whichpreheat boiler combustion air with a novel high temperature CST system based on a solid particle receiver (SPR). This new method of preheating has the potential to increase the solar share of the overall system, improve fuel saving and therefore produce a higher solar to electric conversion efficiency. These benefits result from theSPR solar systems higher operating temperature and integrated thermal storage. The integrated thermal storage also allows a buffered response time for handling transients in the intermittent solar resource. Analysis indicates that air-solarisation of coal plants can result in significantly higher solar to electric conversion efficiency than existing solar hybridisation options. Solarisation by TBS decreases power cycle efficiency due to bleed steam reduction, while solarisation by air-preheating increases the power system efficiency, primarily due to enhanced boiler efficiency brought about by reduced stack losses. The air solarisation option proposed in this paper has beencompared to current TBS with Fresnel based technology. The comparison was conducted by modelling both systems and analysing the thermodynamic heat and mass balance of the steam cycle and boiler using EBSILON®Professional software. Annual simulation tools, which calculate the performance of the solar field, receiver, storage (when applicable) and other system components, were used to model the output of the solar technologies. These tools, coupled with available economic data and cost models for the newly developed solar components, were used to calculate the levelized cost of energy of the compared hybridisation options. It was calculated that the levelized cost of the solar electricity produced by the SPR system was approximately 59%theelectricity produced by the Fresnel hybridisation

Optical Scattering Lengths in Large Liquid-Scintillator Neutrino Detectors

For liquid-scintillator neutrino detectors of kiloton scale, the transparency of the organic solvent is of central importance. The present paper reports on laboratory measurements of the optical scattering lengths of the organic solvents PXE, LAB, and Dodecane which are under discussion for next-generation experiments like SNO+, Hanohano, or LENA. Results comprise the wavelength range from 415 to 440nm. The contributions from Rayleigh and Mie scattering as well as from absorption/re-emission processes are discussed. Based on the present results, LAB seems to be the preferred solvent for a large-volume detector.Comment: 9 pages, 3 figures, accepted for publication by Rev. Scient. Instr

Accelerated 3D multi‐channel B 1 + mapping at 7 T for the brain and heart

Purpose: To acquire accurate volumetric multi‐channel B 1 + $${\mathrm{B}}_1^{+}$$ maps in under 14 s whole‐brain or 23 heartbeats whole‐heart for parallel transmit (pTx) applications at 7 T. Theory and Methods: We evaluate the combination of three recently proposed techniques. The acquisition of multi‐channel transmit array B 1 + $${\mathrm{B}}_1^{+}$$ maps is accelerated using transmit low rank (TxLR) with absolute B 1 + $${\mathrm{B}}_1^{+}$$ mapping (Sandwich) acquired in a B 1 + $${\mathrm{B}}_1^{+}$$ time‐interleaved acquisition of modes (B1TIAMO) fashion. Simulations using synthetic body images derived from Sim4Life were used to test the achievable acceleration for small scan matrices of 24 × 24. Next, we evaluated the method by retrospectively undersampling a fully sampled B 1 + $${\mathrm{B}}_1^{+}$$ library of nine subjects in the brain. Finally, Cartesian undersampled phantom and in vivo images were acquired in both the brain of three subjects (8Tx/32 receive [Rx]) and the heart of another three subjects (8Tx/8Rx) at 7 T. Results: Simulation and in vivo results show that volumetric multi‐channel B 1 + $${\mathrm{B}}_1^{+}$$ maps can be acquired using acceleration factors of 4 in the body, reducing the acquisition time to within 23 heartbeats, which was previously not possible. In silico heart simulations demonstrated a RMS error to the fully sampled native resolution ground truth of 4.2° when combined in first‐order circularly polarized mode (mean flip angle 66°) at an acceleration factor of 4. The 14 s 3D B 1 + $${\mathrm{B}}_1^{+}$$ maps acquired in the brain have a RMS error of 1.9° to the fully sampled (mean flip angle 86°). Conclusion: The proposed method is demonstrated as a fast pTx calibration technique in the brain and a promising method for pTx calibration in the body

Bacterial genomics reveal the complex epidemiology of an emerging pathogen in Arctic and boreal ungulates

Northern ecosystems are currently experiencing unprecedented ecological change, largely driven by a rapidly changing climate. Pathogen range expansion, and emergence and altered patterns of infectious disease, are increasingly reported in wildlife at high latitudes. Understanding the causes and consequences of shifting pathogen diversity and host-pathogen interactions in these ecosystems is important for wildlife conservation, and for indigenous populations that depend on wildlife. Among the key questions are whether disease events are associated with endemic or recently introduced pathogens, and whether emerging strains are spreading throughout the region. In this study, we used a phylogenomic approach to address these questions of pathogen endemicity and spread for Erysipelothrix rhusiopathiae, an opportunistic multi-host bacterial pathogen associated with recent mortalities in arctic and boreal ungulate populations in North America. We isolated E. rhusiopathiae from carcasses associated with large-scale die-offs of muskoxen in the Canadian Arctic Archipelago, and from contemporaneous mortality events and/or population declines among muskoxen in northwestern Alaska and caribou and moose in western Canada. Bacterial genomic diversity differed markedly among these locations; minimal divergence was present among isolates from muskoxen in the Canadian Arctic, while in caribou and moose populations, strains from highly divergent clades were isolated from the same location, or even from within a single carcass. These results indicate that mortalities among northern ungulates are not associated with a single emerging strain of E. rhusiopathiae, and that alternate hypotheses need to be explored. Our study illustrates the value and limitations of bacterial genomic data for discriminating between ecological hypotheses of disease emergence, and highlights the importance of studying emerging pathogens within the broader context of environmental and host factors