The effect of clouds on the earth's radiation balance

The effect of global cloudiness on the radiation balance at the top of the atmosphere is studied in general circulation model experiments. Wintertime simulations were conducted with clouds that had realistic optical properties, and were compared with simulations in which the clouds were transparent to either solar or thermal radiation. Clouds increase the net balance by limiting longwave loss to space, but decrease it by reflecting solar radiation. It is found that the net result of cloudiness is to maintain net radiation which is less than would be realized under clear conditions: Clouds cause the net radiation at the top of the atmosphere to increase due to longwave absorption, but to decrease even more due to cloud reflectance of solar radiation

Peluang Dan Kendala Cendana Dalam Perekonomian Propinsinusa Tenggara Timur

Berbagai peluang untuk tetap menjadikan cendana (Santalum album L.) sebagai komoditas utaraa dan andalan daerah Nusa Tenggara Timur (NTT) disampaikan dalam tulisan ini. Selain itu, mengatasi kendala yang dihadapi dalam upaya pelestarian dan pengembangan cendana, harus tetap melibatkan 3 komponen pelaku yaitu Pemerintah Daerah, Masyarakat dan Pengusaha industri cendana.Untuk itu,beberapa saran dalam upaya dimaksud, baik jangka panjang, jangka pendek maupun dari sisi hukum juga dikemukakan

Phase Space Tomography of Matter-Wave Diffraction in the Talbot Regime

We report on the theoretical investigation of Wigner distribution function (WDF) reconstruction of the motional quantum state of large molecules in de Broglie interference. De Broglie interference of fullerenes and as the like already proves the wavelike behaviour of these heavy particles, while we aim to extract more quantitative information about the superposition quantum state in motion. We simulate the reconstruction of the WDF numerically based on an analytic probability distribution and investigate its properties by variation of parameters, which are relevant for the experiment. Even though the WDF described in the near-field experiment cannot be reconstructed completely, we observe negativity even in the partially reconstructed WDF. We further consider incoherent factors to simulate the experimental situation such as a finite number of slits, collimation, and particle-slit van der Waals interaction. From this we find experimental conditions to reconstruct the WDF from Talbot interference fringes in molecule Talbot-Lau interferometry.Comment: 16 pages, 9 figures, accepted at New Journal of Physic

Soil biological quality of grassland fertilized with adjusted cattle manure slurries in comparison with organic and inorganic fertilizers

We studied the effect of five fertilizers (including two adjusted manure slurries) and an untreated control on soil biota and explored the effect on the ecosystem services they provided. Our results suggest that the available N (NO3- and NH4+) in the soil plays a central role in the effect of fertilizers on nematodes and microorganisms. Microorganisms are affected directly through nutrient availability and indirectly through grass root mass. Nematodes are affected indirectly through microbial biomass and grass root mass. A lower amount of available N in the treatment with inorganic fertilizer was linked to a higher root mass and a higher abundance and proportion of herbivorous nematodes. A higher amount of available N in the organic fertilizer treatments resulted in a twofold higher bacterial activity (measured as bacterial growth rate, viz. thymidine incorporation), a higher proportion of bacterivorous nematodes, a 30% higher potential N mineralization (aerobic incubation), and 25–50% more potentially mineralizable N (anaerobic incubation). Compared to inorganic fertilizer, organic fertilization increased the C total, the N total, the activity of decomposers, and the supply of nutrients via the soil food web. Within the group of organic fertilizers, there was no significant difference in C total, abundances of soil biota, and the potential N mineralization rate. There were no indications that farmyard manure or the adjusted manure slurries provided the ecosystem service “supply of nutrients” better than normal manure slurry. Normal manure slurry provided the highest bacterial activity and the highest amount of mineralizable N and it was the only fertilizer resulting in a positive trend in grass yield over the years 2000–2005. The number of earthworm burrows was higher in the treatments with organic fertilizers compared to the one with the inorganic fertilizer, which suggests that organic fertilizers stimulate the ecosystem service of water regulation more than inorganic fertilizer. The trend towards higher epigeic earthworm numbers with application of farmyard manure and one of the adjusted manure slurries, combined with the negative relation between epigeic earthworms and bulk density and a significantly lower penetration resistance in the same fertilizer types, is preliminary evidence that these two organic fertilizer types contribute more to the service of soil structure maintenance than inorganic fertilize

Diluted maximum-likelihood algorithm for quantum tomography

We propose a refined iterative likelihood-maximization algorithm for reconstructing a quantum state from a set of tomographic measurements. The algorithm is characterized by a very high convergence rate and features a simple adaptive procedure that ensures likelihood increase in every iteration and convergence to the maximum-likelihood state. We apply the algorithm to homodyne tomography of optical states and quantum tomography of entangled spin states of trapped ions and investigate its convergence properties.Comment: v2: Convergence proof adde

First-principles calculation of the temperature dependence of the optical response of bulk GaAs

A novel approach has been developed to calculate the temperature dependence of the optical response of a semiconductor. The dielectric function is averaged over several thermally perturbed configurations that are extracted from molecular dynamic simulations. The calculated temperature dependence of the imaginary part of the dielectric function of GaAs is presented in the range from 0 to 700 K. This approach that explicitly takes into account lattice vibrations describes well the observed thermally-induced energy shifts and broadening of the dielectric function.Comment: 6 pages, 3 figure

Tidal migration of nematodes on an estuarine tidal flat (the Molenplaat, Schelde Estuary, SW Netherlands)

The vertical distribution patterns of the nematode community and of the 10 most dominant nematode species on an intertidal flat in the Schelde Estuary (the Molenplaat, The Netherlands) are described at specific time intervals over a tidal cycle. The observed distribution profiles indicate that vertical migrations occur and are species-specific. The predatory Enoploides longispiculosus and the deposit-feeding Daptonema normandicum migrated upwards at incoming tide and downwards when the flat became exposed, while another deposit feeder,Daptonema setosum, did the opposite. Several abiotic and biotic factors may contribute to the observed patterns. Hydrodynamics, pore water drainage and episodic steep increases in temperature upon low tide exposure as well as vertical movements of prey organisms may have been of particular relevance at the time and site of sampling. However, the impact of each of these factors needs further investigation. The present study corroborates the dynamic nature of vertical distribution profiles of nematodes in intertidal sediments, highlighting the importance of sampling time with respect to the tide, as well as a species approach

Predation rates and prey selectivity in two predacious estuarine nematodes

Enoploides longispiculosus and Adoncholaimus fuscus are representatives of nematode genera prominent in sediments of the North Sea and adjacent estuaries. Both are predatory nematodes, although predation is facultative in the latter. The present study investigates functional responses and prey selectivity in both species through the use of controlled laboratory experiments. Both predators had strongly prey density-dependent predation rates. A maximal predation rate of 4 monhysterid prey nematodes per predator per 24 h was found inE. longispiculosus at prey densities of 200 ind. per petri dish and higher; no such maximal predation rate was found for A. fuscus, indicating that this species was prey-limited at all prey densities tested. Predation rates were strongly affected by temperature, with a Q10 close to 2 between 10 and 20 °C. Incubation in the light resulted in a similar decrease in predation rate compared to dark incubations, as did a temperature decrease from 20 to 10 °C. E. longispiculosus exhibited a clear preference for some nematode prey over others. An encounter probability model indicated that preferences could not be explained by encounter rates. Strike rates were low (E. longispiculosus, and exceptionally low (A. fuscus, indicating that many encounters did not result in attack, or that a portion of the attacks did not result in prey capture. The observed predation rates cannot be supported by prey nematode standing stock and production at the 2 sampling sites used in this study, where E. longispiculosus dominates the nematode community in abundance and, especially, biomass. A. fuscus may mainly derive food from feeding modes other than predation; E. longispiculosus may be prey-limited in its natural habitat. Since this nematode also feeds on other metazoans, it may also impact temporary meiofauna. The high predation rates and prey selectivity of predacious nematodes may be important structuring factors to meiofaunal communities