1,955 research outputs found
Development of innovative industrial cluster strategy using compound real options
No full textThe subject of the study is pilot clusters that are beneficial to a particular region, taking into account the traditions and production areas of the region. The work aims to develop an innovative strategy for state-supported pilot clusters that would allow for flexible management decision making. The proposed method involves the compound real options to be employed in the following order: 1) an option to reduce and abandon the cluster strategy; 2) an option to develop and replicate the experience accumulated in the cluster; 3) an option to switch from and temporarily stop the cluster strategy; and 4) an option to postpone the implementation of the new cluster strategy. As an example of the implementation of the method presented, the authors discuss the strategy for the development of a pilot electric power cluster in the Nizhny Novgorod region presented by the core company TNS energo NN PJSC. The use of the compound real option method enabled the cost increase of the strategy for this cluster – i.e., the effect of its implementation by the core company rose by 89.1%, from 2 710 022 to 5 124 706 thousand Rubles. Thus, using the compound real options precisely in the presented order avoids unreasonable management decisions to exit the current cluster strategy, which would include many tactical opportunities already implemented for cluster development. First, a put option, i.e., an option to reduce and exit the cluster strategy, supplements the evaluation of the current strategy. If the current strategy continues, the other three options are used
Analysis of the magnetotransport channels in tunnel junctions with amorphous
No full textThis work concerns the temperature and bias dependence of the
magnetotransport properties of \chem{Al} oxide-based tunnel
junctions with an amorphous \chem{Co_{60}Fe_{20}B_{20}} soft
ferromagnetic electrode and \chem{CoFe_{10}}-based
polycrystalline hard electrode. The junctions present high tunnel
magnetoresistance of % at room temperature and
% at 5\un{K}. A model that takes magnon-assisted
inelastic tunneling into account fits satisfactorily the parallel
(P) and antiparallel (AP) conductance as a function of
temperature. The extracted fitting parameters are then used to
reproduce the low-bias anomaly of the P and AP conductance at low
temperature
Functional diversity changes over 100 yr of primary succession on a volcanic island: insights into assembly processes
No full textChanges in species diversity following volcanic eruptions have been studied extensively, but our knowledge on functional diversity and community assembly under such conditions is very limited. Here, we study the processes following the destruction of vegetation after a volcanic eruption. Specifically, we investigate (1) the temporal patterns of taxonomic and functional diversity over time since a previous eruption (alpha diversity) and beta diversity, (2) the temporal patterns of 26 individual traits (vegetative characteristics, plant taxa ecological preferences, and regenerative characteristics) providing more detailed information on species strategies at the initial and later stages of succession, and (3) the processes driving species assembly and whether they changed over time since the eruption an eruption. We analyzed data recorded during five floristic censuses that took place between 1911 and 2011, calculated alpha and beta facets of taxonomic and functional diversity and examined how community structure changed over time, using 26 functional characteristics, based on their ability to discern primary from later colonists, including longevity, growth form, Ellenberg’s indicator values, seed production and weight, flower size and sex, pollination type, and dispersal mode. Null model analysis was used to test whether the observed functional diversity deviates from random expectations. Alpha diversity, both taxonomic and functional, increased over time after an eruption, while beta diversity did not display a clear trend. This finding indicates that mainly abiotic processes determine species assembly over time after an eruption (at least for the time span studied here), contrary to theoretical expectations. It is most interesting that, simultaneously, some aspects of diversity indicated the effect of biotic interactions (facilitation and competition) on the assembly of species a few years after an eruption. This finding implies a legacy effect, since a high percentage of perennial species was noticed in the assemblage right after the eruption, as well as the effect of the harsh environmental conditions on the assembly of the plant communities. In conclusion, our results indicate the role of legacy effects in succession (most probably through the survival of underground plant parts) and underline the importance of disturbance history in providing the context needed for understanding effects of past events on succession
Magnetic tunnel junctions with yttrium oxide barrier
No full textMagnetic tunnel junctions have been studied, with YOx barriers prepared by plasma oxidation of a 1.5 nm Y film. We report their junction area resistance, tunnel magnetoresistance (TMR) and barrier parameters (height and thickness) as a function of the oxidation time. For the optimum oxidation time, TMR values of similar to25% are obtained at room temperature and similar to44% at low temperature (5 K). The barrier height extracted from the current-voltage curves, is close to 1 eV, which is less than half of what is usually reported for AlOx-based junctions. Structural and topographical characterization of the multilayes revealed that the YOx layer is amorphous with well-defined, smooth, and correlated interfaces with the ferromagnetic electrodes. (C) 2003 American Institute of Physics
Large tunnel magnetoresistance with plasma oxidized MgO barrier
No full textThis work focuses on magnetic tunnel junctions with a polycrystalline MgO barrier, prepared by plasma oxidation. Combined with Co50Fe50 ferromagnetic electrodes, a large tunnel magnetoresistance (TMR) of 60% is obtained at room temperature. The TMR effect is comparable to state-of-the-art Al oxide barriers with amorphous CoFeB electrodes. It is also found to decrease with the MgO thickness. Two most significant advantages of the MgO junctions are pointed out: (a) The resistance-area product is approximately two orders of magnitude lower than for AlOX- based junctions of the same thickness. (b) MgO presents unsurpassed thermal stability for high annealing temperatures (up to 370 degrees C) and long annealing periods. In addition, for small, patterned elements, we have tested the switching behavior of the soft electrode grown on the polycrystalline MgO barrier. (c) 2005 American Institute of Physics
Constraint on ’t Hooft indices in preon models with complementarity
No full textWe reexamine the SU(7) preon model of Dimopoulos, Raby, and Susskind that is the only model known to violate the conjecture that the ’t Hooft indices for composite models satisfying complementarity are bounded in magnitude by 1. We show that the SU(7) model is in accord with this conjecture due to the hidden ‘‘family symmetry’’ SU(2).journal articl
Lymph Node Cellular Dynamics in Cancer and HIV: What Can We Learn for the Follicular CD4 (Tfh) Cells?
No full textLymph nodes (LNs) are central in the generation of adaptive immune responses. Follicular helper CD4 T (Tfh) cells, a highly differentiated CD4 population, provide critical help for the development of antigen-specific B cell responses within the germinal center. Throughout the past decade, numerous studies have revealed the important role of Tfh cells in Human Immunodeficiency Virus (HIV) pathogenesis as well as in the development of neutralizing antibodies post-infection and post-vaccination. It has also been established that tumors influence various immune cell subsets not only in their proximity, but also in draining lymph nodes. The role of local or tumor associated lymph node Tfh cells in disease progression is emerging. Comparative studies of Tfh cells in chronic infections and cancer could therefore provide novel information with regards to their differentiation plasticity and to the mechanisms regulating their development. © Copyright © 2018 Poultsidi, Dimopoulos, He, Chavakis, Saloustros, Lee and Petrovas
Switching of submicron-sized, antiferromagnetically coupled CoFeB/Ru/CoFeB trilayers
No full textWiese N, Dimopoulos T, Ruhrig M, Wecker J, Reiss G. Switching of submicron-sized, antiferromagnetically coupled CoFeB/Ru/CoFeB trilayers. JOURNAL OF APPLIED PHYSICS. 2005;98(10): 103904.This work reports on the magnetic reversal of submicron-sized elements consisting of an CoFeB/Ru/CoFeB artificial ferrimagnet (AFi). The elements were patterned into ellipses having a width of approximately 250-270 nm and a varying aspect ratio between 1.3 and 8. The coercivity was found to decrease with an increasing imbalance of the magnetic moment of the two antiferromagnetically coupled layers and is therefore strongly affected by an increase of effective anisotropy due to the antiferromagnetic coupling of the two layers. With respect to a single layer of amorphous CoFeB, patterned in comparable elements, the AFi has an increased coercivity. Switching asteroids comparable to single layers were only observed for samples with a high net moment. (c) 2005 American Institute of Physics
The Anopheles FBN9 immune factor mediates Plasmodium species-specific defense through transgenic fat body expression
No full textPolymorphisms detected by random PCR distinguish between different chromosomal forms of Anopheles gambiae.
No full textWe have applied PCR amplification using random primers to distinguish between incipient species of the malaria vector Anopheles gambiae. Individuals belonging to three chromosomally characterized West African forms of this mosquito, which are important epidemiologically as they differ in vectorial capacity, were sampled both from laboratory stocks and from wild populations collected in three localities. The techniques used allowed for the unambiguous classification of the mosquitoes, providing a tool for rapid and efficient diagnosis, which previously relied on cytological examination of polytene chromosome
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