The Question of Low-Lying Intruder States in 8Be^8Be and Neighboring Nuclei

The presence of not yet detected intruder states in $^{8}Be$ e.g. a $J=2^{+}$ intruder at 9 $MeV$ excitation would affect the shape of the $\beta ^{\mp }$-delayed alpha spectra of $^{8}Li$ and $^{8}B$. In order to test the plausibility of this assumption, shell model calculations with up to $4\hbar \omega$ excitations in $^{8}Be$ (and up to $2\hbar \omega$ excitations in $^{10}Be$) were performed. With the above restrictions on the model spaces, the calculations did not yield any low-lying intruder state in $^{8}Be$. Another approach -the simple deformed oscillator model with self-consistent frequencies and volume conservation gives an intruder state in $^{8}Be$ which is lower in energy than the above shell model results, but its energy is still considerably higher than 9 $MeV$.Comment: 16 pages (RevTeX), 1 PS figure. To appear in Phys. Rev.

Recovering coherence from decoherence: a method of quantum state reconstruction

We present a feasible scheme for reconstructing the quantum state of a field prepared inside a lossy cavity. Quantum coherences are normally destroyed by dissipation, but we show that at zero temperature we are able to retrieve enough information about the initial state, making possible to recover its Wigner function as well as other quasiprobabilities. We provide a numerical simulation of a Schroedinger cat state reconstruction.Comment: 8 pages, in RevTeX, 4 figures, accepted for publication in Phys. Rev. A (november 1999

A new interpolation method to measure delta evolution and sediment flux: Application to the late Holocene coastal plain of the Argens River in the western Mediterranean

Rapid environmental changes along the Mediterranean coasts influenced the sedimentary dynamics, shoreline position and human settlements in deltaic areas over the last millennia. An innovative and multiproxy approach using geostatistical modelling was developed to estimate geomorphic evolution and sediment fluxes in deltaic areas, while palaeoecological conditions and environmental changes were assessed from geochemistry and cluster analyses of molluscan fauna. This method was applied to the coastal plain of the Argens River in southern France. Depositional environments of prodelta, delta front, river channel, floodplain, marsh and abandoned channel were identified from the study of facies associations. The late Holocene sediment flux in the Argens River bayhead delta ranged from 15,800 ± 2300 to 52,000 ± 8500 m3·yr−1. The highest rate of sediment deposition between 2500 and 2000 cal yr BP was associated with increased river flooding in southeastern France. A general decrease in subaqueous sediment flux over the past 2500 years was primarily controlled by a decrease in accommodation space and delta slope. From 500 to 0 cal yr BP, a sharp increase in subaerial sediment flux probably due to hydroclimatic change was contemporaneous with a period of high flood frequency during the Little Ice Age. A southward shift of the North Atlantic westerlies combined with either a negative phase of the East Atlantic/West Russian pattern or a negative phase of the East Atlantic pattern coupled to a northward migration of the intertropical convergence zone could have led to increased fluvial activity in the lower Argens valley during the late Holocene

Orbital M1 versus E2 strength in deformed nuclei: A new energy weighted sum rule

Within the unified model of Bohr and Mottelson we derive the following linear energy weighted sum rule for low energy orbital 1$^+$ excitations in even-even deformed nuclei S_{\rm LE}^{\rm lew} (M_1^{\rm orb}) \cong (6/5) \epsilon (B(E2; 0^+_1 \rightarrow 2_1^+ K=0)/Z e^2^2) \mu^2_N with B(E2) the E2 strength for the transition from the ground state to the first excited state in the ground state rotational band, $$ the charge r.m.s. radius squared and $\epsilon$ the binding energy per nucleon in the nuclear ground state. It is shown that this energy weighted sum rule is in good agreement with available experimental data. The sum rule is derived using a simple ansatz for the intrinsic ground state wave function that predicts also high energy 1$^+$ strength at 2$\hbar \omega$ carrying 50\% of the total $m_1$ moment of the orbital M1 operator.Comment: REVTEX (3.0), 9 pages, RU924

Photobiont diversity in lichen symbioses from extreme environments

Fungal–algal relationships—both across evolutionary and ecological scales—are finely modulated by the presence of the symbionts in the environments and by the degree of selectivity and specificity that either symbiont develop reciprocally. In lichens, the green algal genus Trebouxia Puymaly is one of the most frequently recovered chlorobionts. Trebouxia species-level lineages have been recognized on the basis of their morphological and phylogenetic diversity, while their ecological preferences and distribution are still only partially unknown. We selected two cosmopolitan species complexes of lichen-forming fungi as reference models, i.e., Rhizoplaca melanophthalma and Tephromela atra, to investigate the diversity of their associated Trebouxia spp. in montane habitats across their distributional range worldwide. The greatest diversity of Trebouxia species-level lineages was recovered in the altitudinal range 1,000–2,500 m a.s.l. A total of 10 distinct Trebouxia species-level lineages were found to associate with either mycobiont, for which new photobionts are reported. One previously unrecognized Trebouxia species-level lineage was identified and is here provisionally named Trebouxia “A52.” Analyses of cell morphology and ultrastructure were performed on axenically isolated strains to fully characterize the new Trebouxia “A52” and three other previously recognized lineages, i.e., Trebouxia “A02,” T. vagua “A04,” and T. vagua “A10,” which were successfully isolated in culture during this study. The species-level diversity of Trebouxia associating with the two lichen-forming fungi in extreme habitats helps elucidate the evolutionary pathways that this lichen photobiont genus traversed to occupy varied climatic and vegetative regimes

The impact of informal cancer caregiving: A literature review on psychophysiological studies

Caregiving can be experienced as a stressful process, which can cause psychological and physical consequences. The combination of prolonged stress and the physical demands of caregiving may impair the physiological functioning of caregivers and increase the risk of health problems creating considerable stress in the life of caregivers regarding emotional, physical, social and financial areas. This literature review explored studies that used measures of the autonomic nervous system in caregivers of oncology patients such as electrodermal and cardiovascular (re)activity. The results revealed that caregivers had elevated stress levels and a serious autonomic imbalance that may, in the long term, trigger negative health consequences such as infectious diseases, cancer progression, cardiovascular disease and even premature death. The results showed the need to carry out preventive strategies in this population, in order to improve the autonomic profile of caregivers of cancer patients

Test of quantum nonlocality for cavity fields

There have been studies on formation of quantum-nonlocal states in spatially separate two cavities. We suggest a nonlocal test for the field prepared in the two cavities. We couple classical driving fields with the cavities where a nonlocal state is prepared. Two independent two-level atoms are then sent through respective cavities to interact off-resonantly with the cavity fields. The atomic states are measured after the interaction. Bell's inequality can be tested by the joint probabilities of two-level atoms being in their excited or ground states. We find that quantum nonlocality can also be tested using a single atom sequentially interacting with the two cavities. Potential experimental errors are also considered. We show that with the present experimental condition of 5% error in the atomic velocity distribution, the violation of Bell's inequality can be measured.Comment: 14pages, 2figures. accepted to Phys. Rev.