785 research outputs found
Checklist of phytoplankton taxa in the Iranian waters of the Caspian Sea
Phytoplankton taxa composition of the Caspian Sea were evaluated by using samples collected at 12 stations along the Iranian coast of the Caspian Sea between 1996 and 2010. This study identified 158 phytoplankton species consisted of diatoms (70 species), dinoflagellates (23 species), chlorophytes (29 species), cyanophytes (31 species), and euglenoids (5 species). The dominant species were the diatoms Thalassionema nitzschioides, Dactyliosolen fragilissimus, the dinoflagellate Prorocentrum cordatum, and the cyanophyte of genus Oscillatoria. The average species diversity index of phytoplankton community was 1.88 as recorded in this study. There were main changes in phytoplankton composition as compared with previous study. It could be related to the severe human activities and difference in sampling strategies
Optimal Correction of Infeasible System in Linear Equality via Genetic Algorithm
This work is focused on the optimal correction of infeasible system of linear equality. In this paper, for correcting this system, we will make the changes just in the coefficient matrix by using l norm and show that solving this problem is equivalent to solving a fractional quadratic problem. To solve this problem, we use the genetic algorithm. Some examples are provided to illustrate the efficiency and validity of the proposed method
Quantum-dot-spin single-photon interface
Using background-free detection of spin-state-dependent resonance
fluorescence from a single-electron charged quantum dot with an efficiency of
0:1%, we realize a single spin-photon interface where the detection of a
scattered photon with 300 picosecond time resolution projects the quantum dot
spin to a definite spin eigenstate with fidelity exceeding 99%. The bunching of
resonantly scattered photons reveals information about electron spin dynamics.
High-fidelity fast spin-state initialization heralded by a single photon
enables the realization of quantum information processing tasks such as
non-deterministic distant spin entanglement. Given that we could suppress the
measurement back-action to well below the natural spin-flip rate, realization
of a quantum non-demolition measurement of a single spin could be achieved by
increasing the fluorescence collection efficiency by a factor exceeding 20
using a photonic nanostructure
Phytoplankton population structure of the Anzali wetland (2010 and 2011)
Phytoplankton groups are very important producers in the Anzali wetland having a significant role in the quality and need to be constantly studied in term of their sequence and density. This survey was conducted at 6 stations between March 2011 and February 2012. According to the results, 67 different genera (22 Bacillariophyta, 26 Chlorophyta, 9 Cyanobacteria, 5 Cryptophyta, 1 Euglenophyta, 2 Chrysophyta, 1Dinoflgellata and 1 Xanthophyta) were identified. Most observed in Sorkhankol and Karkan stations with the annual average of 24.4±5.6 and 20.4± 5.4 cells/ liter respectively. The Bacillariophyta particularly Cyclotella was dominant in all of the stations, but high abundance of Cyanobacteria in Karkan station from July to mid-October caused the annual average of this phylum to be more than Bacillariophyta. The highest and lowest phytoplankton abundances were observed in September and December, respectively. The number of phytoplankton genera and diversity in this study were less than previous studies
Quantum Teleportation from a Propagating Photon to a Solid-State Spin Qubit
The realization of a quantum interface between a propagating photon used for
transmission of quantum information, and a stationary qubit used for storage
and manipulation, has long been an outstanding goal in quantum information
science. A method for implementing such an interface between dissimilar qubits
is quantum teleportation, which has attracted considerable interest not only as
a versatile quantum-state-transfer method but also as a quantum computational
primitive. Here, we experimentally demonstrate transfer of quantum information
carried by a photonic qubit to a quantum dot spin qubit using quantum
teleportation. In our experiment, a single photon in a superposition state of
two colors -- a photonic qubit is generated using selective resonant excitation
of a neutral quantum dot. We achieve an unprecedented degree of
indistinguishability of single photons from different quantum dots by using
local electric and magnetic field control. To teleport a photonic qubit, we
generate an entangled spin-photon state in a second quantum dot located 5
meters away from the first and interfere the photons from the two dots in a
Hong-Ou-Mandel set-up. A coincidence detection at the output of the
interferometer heralds successful teleportation, which we verify by measuring
the resulting spin state after its coherence time is prolonged by an optical
spin-echo pulse sequence. The demonstration of successful inter-conversion of
photonic and semiconductor spin qubits constitute a major step towards the
realization of on-chip quantum networks based on semiconductor nano-structures.Comment: 12 pages, 3 figures, Comments welcom
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