9,628 research outputs found
Seasonal deuterium excess in a Tien Shan ice core: Influence of moisture transport and recycling in Central Asia
Stable water isotope (δ18O, δD) data from a high elevation (5100 masl) ice core recovered from the Tien Shan Mountains, Kyrgyzstan, display a seasonal cycle in deuterium excess (d = δD − 8*δ18O) related to changes in the regional hydrologic cycle during 1994–2000. While there is a strong correlation (r2 = 0.98) between δ18O and δD in the ice core samples, the regression slope (6.9) and mean d value (23.0) are significantly different than the global meteoric water line values. The resulting time-series ice core d profile contains distinct winter maxima and summer minima, with a yearly d amplitude of ∼15–20‰. Local-scale processes that may affect d values preserved in the ice core are not consistent with the observed seasonal variability. Data from Central Asian monitoring sites in the Global Network of Isotopes in Precipitation (GNIP) have similar seasonal d changes. We suggest that regional-scale hydrological conditions, including seasonal changes in moisture source, transport, and recycling in the Caspian/Aral Sea region, are responsible for the observed spatial and temporal d variability
Quantum transport efficiency and Fourier's law
We analyze the steady-state energy transfer in a chain of coupled two-level
systems connecting two thermal reservoirs. Through an analytic treatment we
find that the energy current is independent of the system size, hence violating
Fourier's law of heat conduction. The classical diffusive behavior in Fourier's
law of heat conduction can be recovered by introducing decoherence to the
quantum systems constituting the chain. Implications of these results on energy
transfer in biological light harvesting systems, and the role of quantum
coherences and entanglement are discussed.Comment: 6 pages, 4 figure
Tree ring analysis of Brachystegia spiciformis and Isoberlinia tomentosa: Evaluation of the enso-signal in the miombo woodland of eastern Africa
Measuring gravitational lensing of the cosmic microwave background using cross correlation with large scale structure
We cross correlate the gravitational lensing map extracted from cosmic
microwave background measurements by the Wilkinson Microwave Anisotropy Probe
(WMAP) with the radio galaxy distribution from the NRAO VLA Sky Survey (NVSS)
by using a quadratic estimator technique. We use the full covariance matrix to
filter the data, and calculate the cross-power spectra for the lensing-galaxy
correlation. We explore the impact of changing the values of cosmological
parameters on the lensing reconstruction, and obtain statistical detection
significances at . The results of all cross correlations pass the
curl null test as well as a complementary diagnostic test using the NVSS data
in equatorial coordinates. We forecast the potential for Planck and NVSS to
constrain the lensing-galaxy cross correlation as well as the galaxy bias. The
lensing-galaxy cross-power spectra are found to be Gaussian distributed.Comment: 16 pages, 10 figure
Studi Awal Penerapan Green Specification Di Indonesia
Perlu ditemukan suatu cara yang dapat secara signifikan mengurangi dampak kerusakan lingkungan dalam proses pembangunan. Salah satunya dengan green specification. Green specification sudah berkembang di negara-negara maju. Sudah banyak peraturan-peraturan dan standar-standar yang dibuat untuk mempermudah dalam pembuatan spesifikasi. Di Indonesia masih belum ada standar green specification yang bisa dipakai sebagai standar. Oleh karena itu, dalam skripsi ini diberikan pengenalan studi literatur yang berguna untuk penelitian tentang penerapannya di Surabaya.Dari studi literatur, dapat disimpulkan bahwa green specification adalah spesifikasi teknis pada proses pembangunan proyek untuk mengurangi dampak kerusakan lingkungan. Perbedaan green specification dengangreenship rating tools terletak pada waktu penggunaan peraturan. Green specification telah banyak dipakai oleh banyak negara di dunia untuk mengurangi dampak kerusakan lingkungan. Dari penelitian berupa kuesioner, melalui analisa mean dapat disimpulkan bahwa secara keseluruhan variabel-variabel tersebut mudah diterapkan kontraktor dan konsultan. Kontraktor lebih mudah untuk menerapkan variabel-variabel tersebut daripada konsultan karena memiliki nilai mean lebih besar dari 3,5. Dari uji ANOVA, dapat diambil kesimpulan bahwa secara keseluruhan terdapat kesamaan yang signifikan antara grade kontraktor terhadap variabel yang diuji. Kecuali pada variabel menanamkan kembali pada lahan yang telah dikerjakan, Merelokasikan kembali galian tanah pada proyek yang sama dan menghindari pemakaian bahan coating yang tidak ramah lingkungan
Experimental and theoretical lifetimes and transition probabilities in Sb I
We present experimental atomic lifetimes for 12 levels in Sb I, out of which
seven are reported for the first time. The levels belong to the 5p(P)6s
P, P and 5p(P)5d P, F and F terms. The
lifetimes were measured using time-resolved laser-induced fluorescence. In
addition, we report new calculations of transition probabilities in Sb I using
a Multiconfigurational Dirac-Hartree-Fock method. The physical model being
tested through comparisons between theoretical and experimental lifetimes for
5d and 6s levels. The lifetimes of the 5d F levels (19.5,
7.8 and 54 ns, respectively) depend strongly on the -value. This is
explained by different degrees of level mixing for the different levels in the
F term.Comment: 10 page
Grapevine leafroll-associated virus 3.
Grapevine leafroll disease (GLD) is one of the most important grapevine viral diseases affecting grapevines worldwide. The impact on vine health, crop yield, and quality is difficult to assess due to a high number of variables, but significant economic losses are consistently reported over the lifespan of a vineyard if intervention strategies are not implemented. Several viruses from the family Closteroviridae are associated with GLD. However, Grapevine leafroll-associated virus 3 (GLRaV-3), the type species for the genus Ampelovirus, is regarded as the most important causative agent. Here we provide a general overview on various aspects of GLRaV-3, with an emphasis on the latest advances in the characterization of the genome. The full genome of several isolates have recently been sequenced and annotated, revealing the existence of several genetic variants. The classification of these variants, based on their genome sequence, will be discussed and a guideline is presented to facilitate future comparative studies. The characterization of sgRNAs produced during the infection cycle of GLRaV-3 has given some insight into the replication strategy and the putative functionality of the ORFs. The latest nucleotide sequence based molecular diagnostic techniques were shown to be more sensitive than conventional serological assays and although ELISA is not as sensitive it remains valuable for high-throughput screening and complementary to molecular diagnostics. The application of next-generation sequencing is proving to be a valuable tool to study the complexity of viral infection as well as plant pathogen interaction. Next-generation sequencing data can provide information regarding disease complexes, variants of viral species, and abundance of particular viruses. This information can be used to develop more accurate diagnostic assays. Reliable virus screening in support of robust grapevine certification programs remains the cornerstone of GLD management
Magnetization damping in a local-density approximation
The linear response of itinerant transition metal ferromagnets to transverse
magnetic fields is studied in a self-consistent adiabatic local-density
approximation. The susceptibility is calculated from a microscopic Hamiltonian,
including spin-conserving impurities, impurity induced spin-orbit interaction
and magnetic impurities using the Keldysh formalism. The Gilbert damping
constant in the Landau-Lifshitz-Gilbert equation is identified, parametrized by
an effective transverse spin dephasing rate, and is found to be inversely
proportional to the exchange splitting. Our result justify the phenomenological
treatment of transverse spin dephasing in the study of current-induced
magnetization dynamics in weak, itinerant ferromagnets by Tserkovnyak
\textit{et al.}. We show that neglect of gradient corrections in the
quasiclassical transport equations leads to incorrect results when the exchange
potential becomes of the order of the Fermi energy.Comment: 11 pages, 41 references, no figure
Eigenfunctions for smooth expanding circle maps
We construct a real-analytic circle map for which the corresponding
Perron-Frobenius operator has a real-analytic eigenfunction with an eigenvalue
outside the essential spectral radius when acting upon -functions.Comment: 10 pages, 2 figure
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