18 research outputs found
ODREDNICE IZRAVNIH STRANIH ULAGANJA U IRANU: PRISTUP GRANICNIM TESTOVIMA
Foreign direct investment (FDI) is counted to be an important variable
to increase capital for domestic investors and improvement of capital for-
mation in host country so almost all countries want to attract FDI. This
paper attempted to investigate the impact of openness, exchange rate and
infrastructures on FDI in Iran using the bounds testing (ARDL) approach
to co integration. The data span is from 1975 to 2007. The results indi-
cated that when FDI is the dependent variable there is co integration. We
found all variables have positive and signicant impact on Irans FDI in
long-run and short-run, except openness that has no impact on.Izravna strana ulaganja (FDI) se smatraju vaznom varijablom za povecanje
kapitala domacih investitora i poboljanja stvaranja kapitala u zemlji domacinu
tako da gotovo sve zemlje zele privuci FDI. Ovaj rad je pokuao istraµziti utjecaj
otvorenosti, teµcaja i infrastrukture na FDI u Iranu koristeci granicne testove
(ARDL) u pristupu kointegraciji. Raspon podataka ide od 1975. do 2007.
Rezultati ukazuju da postoji kointegracija kada je FDI zavisna varijabla. Za-
kljuµcili smo da sve varijable imaju znaµcajan pozitivan efekt na FDI u Iranu kako
dugoroµcno tako i kratkoroµcno, osim otvorenosti koja kratkoroµcno gledano nema
nikakav utjecaj na FDI
Effect of Bending Anisotropy on the 3D Conformation of Short DNA Loops
The equilibrium three dimensional shape of relatively short loops of DNA is
studied using an elastic model that takes into account anisotropy in bending
rigidities. Using a reasonable estimate for the anisotropy, it is found that
cyclized DNA with lengths that are not integer multiples of the pitch take on
nontrivial shapes that involve bending out of planes and formation of kinks.
The effect of sequence inhomogeneity on the shape of DNA is addressed, and
shown to enhance the geometrical features. These findings could shed some light
on the role of DNA conformation in protein--DNA interactions
How to determine local elastic properties of lipid bilayer membranes from atomic-force-microscope measurements: A theoretical analysis
Measurements with an atomic force microscope (AFM) offer a direct way to
probe elastic properties of lipid bilayer membranes locally: provided the
underlying stress-strain relation is known, material parameters such as surface
tension or bending rigidity may be deduced. In a recent experiment a
pore-spanning membrane was poked with an AFM tip, yielding a linear behavior of
the force-indentation curves. A theoretical model for this case is presented
here which describes these curves in the framework of Helfrich theory. The
linear behavior of the measurements is reproduced if one neglects the influence
of adhesion between tip and membrane. Including it via an adhesion balance
changes the situation significantly: force-distance curves cease to be linear,
hysteresis and nonzero detachment forces can show up. The characteristics of
this rich scenario are discussed in detail in this article.Comment: 14 pages, 9 figures, REVTeX4 style. New version corresponds to the
one accepted by PRE. The result section is restructured: a comparison to
experimental findings is included; the discussion on the influence of
adhesion between AFM tip and membrane is extende
Topological diversity of chromatin fibers: Interplay between nucleosome repeat length, DNA linking number and the level of transcription
The spatial organization of nucleosomes in 30-nm fibers remains unknown in detail. To tackle this problem, we analyzed all stereochemically possible configurations of two-start chromatin fibers with DNA linkers L = 10-70 bp (nucleosome repeat length NRL = 157-217 bp). In our model, the energy of a fiber is a sum of the elastic energy of the linker DNA, steric repulsion, electrostatics, and the H4 tail-acidic patch interaction between two stacked nucleosomes. We found two families of energetically feasible conformations of the fibers—one observed earlier, and the other novel. The fibers from the two families are characterized by different DNA linking numbers—that is, they are topologically different. Remarkably, the optimal geometry of a fiber and its topology depend on the linker length: the fibers with linkers L = 10n and 10n + 5 bp have DNA linking numbers per nucleosome DLk >>-1.5 and -1.0, respectively. In other words, the level of DNA supercoiling is directly related to the length of the inter-nucleosome linker in the chromatin fiber (and therefore, to NRL). We hypothesize that this topological polymorphism of chromatin fibers may play a role in the process of transcription, which is known to generate different levels of DNA supercoiling upstream and downstream from RNA polymerase. A genome-wide analysis of the NRL distribution in active and silent yeast genes yielded results consistent with this assumption
How to determine local elastic properties of lipid bilayer membranes from atomic-force-microscope measurements: A theoretical analysis
Measurements with an atomic force microscope (AFM) offer a direct way to probe elastic properties of lipid bilayer membranes locally: provided the underlying stress-strain relation is known, material parameters such as surface tension or bending rigidity may be deduced. In a recent experiment a pore-spanning membrane was poked with an AFM tip, yielding a linear behavior of the force-indentation curves. A theoretical model for this case is presented here which describes these curves in the framework of Helfrich theory. The linear behavior of the measurements is reproduced if one neglects the influence of adhesion between tip and membrane. Including it via an adhesion balance changes the situation significantly: force-distance curves cease to be linear, hysteresis and nonzero detachment forces can show up. The characteristics of this rich scenario are discussed in detail in this paper.</p