1,038,816 research outputs found
The Medvedev Presidency: Russia's Direction and the Implications for Foreign Policy
No full textBefore the economic crisis of late 2008, Vladimir Putin’s political regime ensured the election of Dmitry Medvedev to the office of the presidency while Putin shifted to the role of prime minister—a move intended to solidify the Putin administration’s hold over the Kremlin. Supposedly, the Medvedev-Putin alliance sought to modernize the raw-materials-based economy in an attempt to improve its level of vulnerability. However, the fall of oil prices has precipitated disastrous consequences on Russia’s economy, and, as a result, the stability of the Medvedev-Putin regime has faltered. It is now unclear what the power dynamic between Medvedev and Putin will be, and if Putin will continue to maintain his dominant position in Russian politics. Much of the reason for the current regime’s grip on power is the general dissatisfaction with the reforms of the early 1990. This recent return to a bureaucratic economic system and a political system headed by an autocratic-style leader begat a period of prosperity and renewed the dream of regaining the geopolitical status Russia had during the Soviet period. At the present, Russia is ill-equipped to handle many of the challenges wrought by the economic crisis, and the ruling elite has lost many of its financial resources and public support. It is still unclear whether the current regime will survive the challenges it currently faces. Although there exists a possibility for an alternative, liberal governing model to emerge, it is equally possible that the Putin government will find a way to uphold the status quo. This is a profoundly uncertain period in Russia’s political development
Optimal Omnitig Listing for Safe and Complete Contig Assembly
No full textGenome assembly is the problem of reconstructing a genome sequence from a set of reads from a sequencing experiment. Typical formulations of the assembly problem admit in practice many genomic reconstructions, and actual genome assemblers usually output contigs, namely substrings that are promised to occur in the genome. To bridge the theory and practice, Tomescu and Medvedev [RECOMB 2016] reformulated contig assembly as finding all substrings common to all genomic reconstructions. They also gave a characterization of those walks (omnitigs) that are common to all closed edge-covering walks of a (directed) graph, a typical notion of genomic reconstruction. An algorithm for listing all maximal omnitigs was also proposed, by launching an exhaustive visit from every edge.
In this paper, we prove new insights about the structure of omnitigs and solve several open questions about them. We combine these to achieve an O(nm)-time algorithm for outputting all the maximal omnitigs of a graph (with n nodes and m edges). This is also optimal, as we show families of graphs whose total omnitig length is Omega(nm). We implement this algorithm and show that it is 9-12 times faster in practice than the one of Tomescu and Medvedev [RECOMB 2016]
Disk Compression of k-mer Sets
No full textK-mer based methods have become prevalent in many areas of bioinformatics. In applications such as database search, they often work with large multi-terabyte-sized datasets. Storing such large datasets is a detriment to tool developers, tool users, and reproducibility efforts. General purpose compressors like gzip, or those designed for read data, are sub-optimal because they do not take into account the specific redundancy pattern in k-mer sets. In our earlier work (Rahman and Medvedev, RECOMB 2020), we presented an algorithm UST-Compress that uses a spectrum-preserving string set representation to compress a set of k-mers to disk. In this paper, we present two improved methods for disk compression of k-mer sets, called ESS-Compress and ESS-Tip-Compress. They use a more relaxed notion of string set representation to further remove redundancy from the representation of UST-Compress. We explore their behavior both theoretically and on real data. We show that they improve the compression sizes achieved by UST-Compress by up to 27 percent, across a breadth of datasets. We also derive lower bounds on how well this type of compression strategy can hope to do
TREKIS-3
No full text<p><a href="https://github.com/N-Medvedev/TREKIS-3#trekis--time-resolved-electron-kinetics-in-shi-irradiated-solids">TREKIS : Time Resolved Electron Kinetics in SHI Irradiated Solids</a></p>
<p>Version 3.1.3 update 08.05.2024</p>
<p><strong>Monte-Carlo code modelling electronic kinetics after swift-heavy ion impact on matter</strong></p>
<p>Up-to-date version available at:<a href="http://%20https//github.com/N-Medvedev/TREKIS-3"> https://github.com/N-Medvedev/TREKIS-3</a></p>
<p><strong>Disclaimer</strong></p>
<p>Although we endeavour to ensure that the code TREKIS-3 and results delivered are correct, no warranty is given as to its accuracy. We assume no responsibility for possible errors or omissions. We shall not be liable for any damage arising from the use of this code or its parts or any results produced with it, or from any action or decision taken as a result of using this code or any related material.</p>
<p>This code is distributed <em>as is</em> for non-commercial peaceful purposes only, such as research and education. It is <strong>explicitly prohibited</strong> to use the code, its parts, its results or any related material for military-related and other than peaceful purposes. By using this code or its materials, you agree with these terms and conditions.</p>
<p><strong>Update 3.1.3</strong>:</p>
<p>Bugfix in automatic setting of single-pole CDF coefficients; bugfix/patch for interpreting chemical formula; bugfix in Auger-decay (for some elements with shells closer than bandgap); plus minor improvements.</p>
<p><strong>References</strong></p>
<p>N. Medvedev, A.E. Volkov, R. Rymzhanov, F. Akhmetov, S. Gorbunov, R. Voronkov, P. Babaev, "Frontiers, challenges, and solutions in modeling of swift heavy ion effects in materials", J. Appl. Phys. 133, 100701 (2023) https://doi.org/10.1063/5.0128774</p>If you use this software, please cite it as below
Heating and cooling of the thermosphere by internal gravity waves
No full textFor the first time, estimates of heating and cooling in the upper thermosphere due to dissipating and breaking gravity waves ( GWs) of tropospheric origin have been obtained with a comprehensive general circulation model ( GCM). A GW parameterization specifically designed for thermospheric heights has been implemented in the CMAT2 GCM covering altitudes from the tropopause to the F-2 region, and simulations for the June solstice have been performed. They reveal that the net thermal effect of GWs above the turbopause is cooling. The largest ( up to -170 K d(-1) in a zonally and temporally averaged sense) cooling takes place in the high latitudes of both hemispheres near 210 km. The instantaneous values of heating and cooling rates are highly variable, and reach up to 500 and -3000 K d(-1) in the F-2 region, respectively. Inclusion of the GW thermal effects reduces the simulated model temperatures by up to 200 K over the summer pole and by 100 to 170 K at other latitudes near 210 km
Indostola Medvedev 1991
No full textIndostola Medvedev, 1991 Indostola Medvedev, 1991:557 (original description). Type species: Indostola pulchella Medvedev, 1991 (by original designation). Diagnosis. The genus Indostola is characterized by eyes not divided into upper and lower parts by genae; eyes in lateral view not diminished to narrow transverse stripe of facets in lower part (Figs 27–28) as in Stenosis Herbst, 1799 (see MEDVEDEV 1994, Fig. 25); pronotum longer than wide and distinctly narrower than head; tempora almost parallel for one eye length behind posterior margin of eyes. Remarks. The illustration of the elytra in MEDVEDEV (1991: Fig. 1) is not accurate, as in fact the elytra are narrowing gradually to elytral base (see Fig. 1 in this paper).Published as part of Fouquè, René, 2015, A review of the genera Indostola, Tagenostola, Indochillus, Pseudethas, and Pseudochillus gen. nov. in South East Asia (Coleoptera: Tenebrionidae: Stenosini), pp. 217-242 in Acta Entomologica Musei Nationalis Pragae 55 (1) on page 219, DOI: 10.5281/zenodo.530464
Monolepta saudica Medvedev 1996
No full textMonolepta saudica Medvedev, 1996 Distribution. Oman, Saudi Arabia, Yemen (MEDVEDEV 1996, SCHLICH & WAGNER 2010).Published as part of Bezděk, Jan, 2012, Galerucinae (Coleoptera: Chrysomelidae) of Socotra Island, with a review of taxa recorded from Yemen, pp. 403-428 in Acta Entomologica Musei Nationalis Pragae 52 on page 426, DOI: 10.5281/zenodo.533972
Taumacera centromaculata Medvedev 2008
No full textTaumacera centromaculata Medvedev, 2008 Taumacera centromaculata Medvedev, 2008: 432 (original description) Type material examined. PARATYPE: ♀ (only photograph seen), ‘INDONESIA, BALI / Danau Buyan, 1300 m / 19.- 21.2.1994 / Bolm lgt. [w, p] // PARATYPUS [p] / Taumacera / centromaculata m. [h] / L. Medvedev det. [p] 2008 [r, h]’ (LMRM).Published as part of Bezděk, Jan, 2019, Taumacera revisited, with new synonyms, new combinations and a revised catalogue of the species (Coleoptera: Chrysomelidae: Galerucinae), pp. 23-52 in Acta Entomologica Musei Nationalis Pragae (Acta. Ent. Mus. Natl. Pragae) (Acta. Ent. Mus. Natl. Pragae) 59 (1) on page 30, DOI: 10.2478/aemnp-2019-0003, http://zenodo.org/record/450552
Ivalia fulva Medvedev
No full textIvalia fulva Medvedev Taizonia fulva Medvedev, 1993: 366. Type locality: India: Darjeeling. Distribution. Nepal, North India, Laos.Published as part of Nadein, Konstantin S., 2013, Ivalia Jacoby-a flea beetle genus new to Australia (Coleoptera: Chrysomelidae: Galerucinae), pp. 384-400 in Zootaxa 3669 (3) on page 396, DOI: 10.11646/zootaxa.3669.3.11, http://zenodo.org/record/526676
Ivalia fanxipana Medvedev
No full textIvalia fanxipana Medvedev Ivalia fanxipana Medvedev, 2009: 95. Type locality: Vietnam: Lao Cai. Distribution. North Vietnam.Published as part of Nadein, Konstantin S., 2013, Ivalia Jacoby-a flea beetle genus new to Australia (Coleoptera: Chrysomelidae: Galerucinae), pp. 384-400 in Zootaxa 3669 (3) on page 396, DOI: 10.11646/zootaxa.3669.3.11, http://zenodo.org/record/526676
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