A view from the countryside : pollen from a field at Mistra Valley, Malta

Although historical sources for the Early Modern development of the Maltese landscape are abundant and well-documented, these records are uncorroborated by other forms of evidence. As part of investigations of the development of a field system at Mistra Valley, Malta, a sample was taken from a waterlain layer at the base of a field-fill on the edge of the valley-floor in Mistra Valley. Pollen and other analyses were done on this layer to identify the environment and agriculture of an early stage in the field system.peer-reviewe

First time determination of the microscopic structure of a stripe phase: Low temperature NMR in La2NiO4.17

The experimental observations of stripes in superconducting cuprates and insulating nickelates clearly show the modulation in charge and spin density. However, these have proven to be rather insensitive to the harmonic structure and (site or bond) ordering. Using 139La NMR in La2NiO4.17, we show that in the 1/3 hole doped nickelate below the freezing temperature the stripes are strongly solitonic and site ordered with Ni3+ ions carrying S=1/2 in the domain walls and Ni2+ ions with S=1 in the domains.Comment: 4 pages including 4 figure

On the structure of the energy distribution function in the hopping regime

The impact of the dispersion of the transport coefficients on the structure of the energy distribution function for charge carriers far from equilibrium has been investigated in effective-medium approximation for model densities of states. The investigations show that two regimes can be observed in energy relaxation processes. Below a characteristic temperature the structure of the energy distribution function is determined by the dispersion of the transport coefficients. Thermal energy diffusion is irrelevant in this regime. Above the characteristic temperature the structure of the energy distribution function is determined by energy diffusion. The characteristic temperature depends on the degree of disorder and increases with increasing disorder. Explicit expressions for the energy distribution function in both regimes are derived for a constant and an exponential density of states.Comment: 16 page

Extreme daily rainfall in Pakistan and north India: scale-interactions, mechanisms, and precursors

While much of India is used to heavy precipitation and frequent low-pressure systems during the summer monsoon, towards the northwest and into Pakistan, such events are uncommon. Here, as much as a third of the annual rainfall is delivered sporadically during the winter monsoon by western disturbances. Such events of sparse but heavy precipitation in this region of typically mountainous valleys in the north and desert in the south can be catastrophic, as in the case of the Pakistan floods of July 2010. In this study, we identify extreme precipitation events (EPEs) in a box approximately covering this region (65◦ -78◦W, 25◦ -38◦N) using the APHRODITE gauge-based precipitation product. The role of the large-scale circulation in causing EPEs is investigated: it is found that, during winter, they often coexist with an upper-tropospheric Rossby wave train that has prominent anomalous southerlies over the region of interest. These winter EPEs are also found to be strongly colocated with incident western disturbances whereas those occurring during the summer are found to have a less direct relationship. Conversely, summer EPEs are found to have a strong relationship with tropical lows. A detailed Lagrangian method is used to explore possible sources of moisture for such events, and suggests that in winter, the moisture is mostly drawn from the Arabian Sea, whereas during the summer, it comes from along the African coast and the Indian monsoon trough region

2015 Update on Acute Adverse Reactions to Gadolinium based Contrast Agents in Cardiovascular MR. Large Multi-National and Multi-Ethnical Population Experience With 37788 Patients From the EuroCMR Registry

Objectives: Specifically we aim to demonstrate that the results of our earlier safety data hold true in this much larger multi-national and multi-ethnical population. Background: We sought to re-evaluate the frequency, manifestations, and severity of acute adverse reactions associated with administration of several gadolinium- based contrast agents during routine CMR on a European level. Methods: Multi-centre, multi-national, and multi-ethnical registry with consecutive enrolment of patients in 57 European centres. Results: During the current observation 37788 doses of Gadolinium based contrast agent were administered to 37788 patients. The mean dose was 24.7 ml (range 5–80 ml), which is equivalent to 0.123 mmol/kg (range 0.01 - 0.3 mmol/kg). Forty-five acute adverse reactions due to contrast administration occurred (0.12 %). Most reactions were classified as mild (43 of 45) according to the American College of Radiology definition. The most frequent complaints following contrast administration were rashes and hives (15 of 45), followed by nausea (10 of 45) and flushes (10 of 45). The event rate ranged from 0.05 % (linear non-ionic agent gadodiamide) to 0.42 % (linear ionic agent gadobenate dimeglumine). Interestingly, we also found different event rates between the three main indications for CMR ranging from 0.05 % (risk stratification in suspected CAD) to 0.22 % (viability in known CAD). Conclusions: The current data indicate that the results of the earlier safety data hold true in this much larger multi-national and multi-ethnical population. Thus, the “off-label” use of Gadolinium based contrast in cardiovascular MR should be regarded as safe concerning the frequency, manifestation and severity of acute events

Job Growth in Early Transition: Comparing Two Paths

Small start-up firms are the engine of job creation in early transition and yet little is known about the characteristics of this new sector. We seek to identify patterns of job growth in this sector in terms of niches left from central planning and ask about differences in job creation across two different transition economies: Estonia, which experienced rapid destruction of the pre-existing firms, and the Czech Republic, which reduced the old sector gradually. We find job growth within industries to be quantitatively more important than job growth due to across-industry reallocation. Furthermore, the industrial composition of startups is strikingly similar in the two countries. We offer convergence to "western" industry firm-size distributions as an explanation. We also find regularities in wage evolution across new and old firms, including small differences in job quality across the two transition paths.http://deepblue.lib.umich.edu/bitstream/2027.42/39888/3/wp503.pd

Relationship between incommensurability and superconductivity in Peierls distorted charge-density-wave systems

We study the pairing potential induced by fluctuations around a charge-density wave (CDW) with scattering vector Q by means of the Froehlich transformation. For general commensurability M, defined as |k+M*Q>=|k>, we find that the intraband pair scattering within the M subbands scales with M whereas the interband pair scattering becomes suppressed with increasing CDW order parameter. As a consequence superconductivity is suppressed when the Fermi energy is located between the subbands as it is usually the case for nesting induced CDW's, but due to the vertex renormalization it can be substantially enhanced when the chemical potential is shifted sufficiently inside one of the subbands. The model can help to understand the experimentally observed dependence of the superconducting transition temperature from the stripe phase incommensurability in the lanthanum cuprates.Comment: 6 pages, 3 figure

Cosmic Voids: structure, dynamics and galaxies

In this review we discuss several aspects of Cosmic Voids. Voids are a major component of the large scale distribution of matter and galaxies in the Universe. They are of instrumental importance for understanding the emergence of the Cosmic Web. Their relatively simple shape and structure makes them into useful tools for extracting the value of a variety cosmic parameters, possibly including even that of the influence of dark energy. Perhaps most promising and challenging is the issue of the galaxies found within their realm. Not only does the pristine environment of voids provide a promising testing ground for assessing the role of environment on the formation and evolution of galaxies, the dearth of dwarf galaxies may even represent a serious challenge to the standard view of cosmic structure formation.Comment: 29 pages, 12 figures, invited review COSPA2008, Pohang, Korea. Modern Physics Letters A, accepted. For high-res version see http://www.astro.rug.nl/~weygaert/voids.cospa2008.weygaert.pd

17O NMR study of q=0 spin excitations in a nearly ideal S=1/2 1D Heisenberg antiferromagnet, Sr2CuO3, up to 800 K

We used 17O NMR to probe the uniform (wavevector q=0) electron spin excitations up to 800 K in Sr2CuO3 and separate the q=0 from the q=\pm\pi/a staggered components. Our results support the logarithmic decrease of the uniform spin susceptibility below T ~ 0.015J, where J=2200 K. From measurement of the dynamical spin susceptibility for q=0 by the spin-lattice relaxation rate 1/T_{1}, we demonstrate that the q=0 mode of spin transport is ballistic at the T=0 limit, but has a diffusion-like contribution at finite temperatures even for T << J.Comment: Submitted to Phys. Rev. Lett. 4 pages, 4 figure

Monitoring of tritium purity during long-term circulation in the KATRIN test experiment LOOPINO using laser Raman spectroscopy

The gas circulation loop LOOPINO has been set up and commissioned at Tritium Laboratory Karlsruhe (TLK) to perform Raman measurements of circulating tritium mixtures under conditions similar to the inner loop system of the neutrino-mass experiment KATRIN, which is currently under construction. A custom-made interface is used to connect the tritium containing measurement cell, located inside a glove box, with the Raman setup standing on the outside. A tritium sample (purity > 95%, 20 kPa total pressure) was circulated in LOOPINO for more than three weeks with a total throughput of 770 g of tritium. Compositional changes in the sample and the formation of tritiated and deuterated methanes CT_(4-n)X_n (X=H,D; n=0,1) were observed. Both effects are caused by hydrogen isotope exchange reactions and gas-wall interactions, due to tritium {\beta} decay. A precision of 0.1% was achieved for the monitoring of the T_2 Q_1-branch, which fulfills the requirements for the KATRIN experiment and demonstrates the feasibility of high-precision Raman measurements with tritium inside a glove box