101,816 research outputs found
Immunity to K1 killer toxin: internal TOK1 blockade.
K1 killer strains of Saccharomyces cerevisiae harbor RNA viruses that mediate secretion of K1, a protein toxin that kills virus-free cells. Recently, external K1 toxin was shown to directly activate TOK1 channels in the plasma membranes of sensitive yeast cells, leading to excess potassium flux and cell death. Here, a mechanism by which killer cells resist their own toxin is shown: internal toxin inhibits TOK1 channels and suppresses activation by external toxin
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Natural and anthropogenic rapid changes in the Kara-Bogaz Gol over the last two centuries reconstructed from palynological analyses and a comparison to instrumental records
Palynological analyses (pollen and dinocysts) of a sediment core taken in the Kara-Bogaz Gol have been used to
reconstruct rapid and catastrophic environmental changes over the last two centuries (chronology based on 210Pb). A
natural cyclicity (65 years) of water level changes in the Caspian Sea and in the Kara-Bogaz Gol and anthropogenic
factors (building of a dam separating the CS and the KBG waters) combine to induce rapid changes in water levels of
the KBG, in the salinity of its waters and in vegetation cover of its surroundings. The impact of low water levels on
the dinocysts is marked by a lower diversity and the survival of two species that are typical of the KBG, the Caspian
Sea species present in the KBG having disappeared. During periods of higher water levels (AD 1871 to 1878), the
lake is surrounded by a steppe-like vegetation dominated by Artemisia; whereas during periods of low water levels
(AD 1878 to 1913 and AD 1955-1998), the emerged shore are colonised by Chenopodiaceae. The period of AD 1913
to 1955 corresponding to decreasing water levels has an extremely low pollen concentration and a maximum of
reworking of arboreal taxa. During the last low-level period, humans responded by abandoning the shores of the bay.
What happened to the KBG can be used as an example of what may happen in the future for the Aral Sea.
A problem of reworking of Tertiary dinocysts into modern deposits has been detected owing to the knowledge of the
modern dinoflagellate assemblages recently made available through a water survey. A comparison to modern surface
pollen samples from Central Asia (Anzali, Caspian Sea south and central basins, Aral Sea, Lake Balkhash, Lake
Issyk-Kul and the Chinese Tien-Shan range) allows us to establish the potential reworking of at least five arboreal
pollen taxa possibly by run-off and dust storms
A molecular target for viral killer toxin: TOK1 potassium channels.
Killer strains of S. cerevisiae harbor double-stranded RNA viruses and secrete protein toxins that kill virus-free cells. The K1 killer toxin acts on sensitive yeast cells to perturb potassium homeostasis and cause cell death. Here, the toxin is shown to activate the plasma membrane potassium channel of S. cerevisiae, TOK1. Genetic deletion of TOK1 confers toxin resistance; overexpression increases susceptibility. Cells expressing TOK1 exhibit toxin-induced potassium flux; those without the gene do not. K1 toxin acts in the absence of other viral or yeast products: toxin synthesized from a cDNA increases open probability of single TOK1 channels (via reversible destabilization of closed states) whether channels are studied in yeast cells or X. laevis oocytes
Urban Deforestation and Urban Development
This paper has developed a model of a single forest owner operating with perfect foresight in a dynamic open-city environment that allows for switching between alternative competing land uses (forest and urban use) at some point in the future. The model also incorporates external values of an even-aged standing forest in addition to the value of timber when it is harvested. Timber is exploited based on a multiple rotation model a la Faustmann with clear-cut harvesting. In contrast to previous models, our alternative land use to forest land is endogenous. Within this framework, we study the problem of the private owner as well as that of the social planner, when choosing the time to harvest, the time to convert land and the intensity of development. We also examine the extent to which the two-way linkage between urban development and forest management practices (timber production and provision of forest amenities) contributes to economic efficiency and improvements in non-market forest benefits. Finally, we consider policy options available to a regulator seeking to achieve improvements in efficiency including anti-sprawl policies (impact fees and density controls) and forest policies such a yield tax. Numerical simulations illustrate our analytical results. JEL codes:Deforestation, Urban Development, Forest Management Practices, Anti-Sprawl Policies, Yield Taxes
Hygrothermal performance of building envelopes in the tropics under operative conditions : condensation and mould growth risk appraisal
Poor indoor hygrothermal performance increases the risk of indoor moisture problems and
deterioration due to mould growth, corrosion and damage to archival materials. Hence,
proper control of indoor thermohygric intensity abates indoor moisture and its associated
problems. This paper presents the results of envelopes hygrothermal performance
assessments in a hot and humid climate building with varying operational profile between
adjacent spaces. The case-studied building runs on 24hrs cooling mode in one part against
natural and/or mechanical supply-exhaust fan means on the other. In-situ experiments were
combined with hygrothermal analytical methods to assess the envelope thermal quality
together with the operative conditions against condensation and mould growth risks. The
results show that the building is overcooled leading to poor envelope hygrothermal
performance with associated condensation and mould growth problems on non-airconditioned sides of the envelopes
Cooper pairing near charged black holes
We show that a quartic contact interaction between charged fermions can lead
to Cooper pairing and a superconducting instability in the background of a
charged asymptotically Anti-de Sitter black hole. For a massless fermion we
obtain the zero mode analytically and compute the dependence of the critical
temperature T_c on the charge of the fermion. The instability we find occurs at
charges above a critical value, where the fermion dispersion relation near the
Fermi surface is linear. The critical temperature goes to zero as the marginal
Fermi liquid is approached, together with the density of states at the Fermi
surface. Besides the charge, the critical temperature is controlled by a four
point function of a fermionic operator in the dual strongly coupled field
theory.Comment: 1+33 pages, 4 figure
Strategi Pemasaran Produk Gadai Syariah dalam Upaya Menarik Minat Nasabah pada Pegadaian Syariah
Islam merupakan suatu sistem dan jalan hidup yang utuh dan terpadu, Islam memberikan panduan yang dinamis terhadap semua aspek kehidupan termasuk sektor bisnis dan transaksi keuangan. Hal ini terlihat dengan menggunakan prinsip syariah, karena diharapkan dengan menggunakan prinsip syariah Islam dapat memberikan mashlahat bagi umat manusia dan salah satu kelebihan dari lembaga keuangan syariah adalah tidak boleh meminta kelebihan dari pokok pinjaman, karena hal yang demikian itu termasuk riba. Sebagaimana kita ketahui bahwa riba didalam Islam itu sangatlah diharamkan. Perkembangan lembaga-lembaga keuangan Islam di Indonesia dapat dikategorikan cepat dan yang menjadi salah satu faktor tersebut adalah adanya keyakinan pada masyarakat muslim bahwa perbankan konvensional itu mengandung unsur riba yang dilarang oleh agama IslamDOI: 10.15408/aiq.v1i2.246
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