42 research outputs found
Primary thermometry in the intermediate Coulomb blockade regime
We investigate Coulomb blockade thermometers (CBT) in an intermediate
temperature regime, where measurements with enhanced accuracy are possible due
to the increased magnitude of the differential conductance dip. Previous
theoretical results show that corrections to the half width and to the depth of
the measured conductance dip of a sensor are needed, when leaving the regime of
weak Coulomb blockade towards lower temperatures. In the present work, we
demonstrate experimentally that the temperature range of a CBT sensor can be
extended by employing these corrections without compromising the primary nature
or the accuracy of the thermometer.Comment: 8 pages, 4 figure
Variabilidade no cpDNA em Manilkara huberi, espécie sob manejo sustentåvel na AmazÎnia brasileira
Aspects of Orchidaceae distribution in Costa Rica and northwestern South America: a study on similarity with emphasis on the Amazonian Region
Myrtaceae throughout the Espinhaço Mountain Range of centraleastern Brazil: floristic relationships and geoclimatic controls
Pervasive gaps in Amazonian ecological research
Biodiversity loss is one of the main challenges of our time, and attempts to address it require a clear understanding of how ecological communities respond to environmental change across time and space. While the increasing availability of global databases on ecological communities has advanced our knowledge of biodiversity sensitivity to environmental changes, vast areas of the tropics remain understudied. In the American tropics, Amazonia stands out as the world's most diverse rainforest and the primary source of Neotropical biodiversity, but it remains among the least known forests in America and is often underrepresented in biodiversity databases. To worsen this situation, human-induced modifications may eliminate pieces of the Amazon's biodiversity puzzle before we can use them to understand how ecological communities are responding. To increase generalization and applicability of biodiversity knowledge, it is thus crucial to reduce biases in ecological research, particularly in regions projected to face the most pronounced environmental changes. We integrate ecological community metadata of 7,694 sampling sites for multiple organism groups in a machine learning model framework to map the research probability across the Brazilian Amazonia, while identifying the region's vulnerability to environmental change. 15%â18% of the most neglected areas in ecological research are expected to experience severe climate or land use changes by 2050. This means that unless we take immediate action, we will not be able to establish their current status, much less monitor how it is changing and what is being lost
Single-Shot Readout of Singlet-Triplet Qubit States in a Si/SiGe Double Quantum Dot
The spin singlet and triplet states of a two-electron double quantum dot can be used to form a logical qubit that combines fast manipulation and a spin readout mechanism. We demonstrate single-shot readout of the two-electron states of a Si/SiGe double quantum dot using a quantum-point-contact charge sensor and spin-to-charge conversion. From the statistics of multiple singleshot measurements, we find the lifetimes of the spin states as a function of in-plane magnetic field. The lifetimes of the singlet and T0 triplet are both ~10ms and insensitive to magnetic field. The Ttriplet lifetime increases with magnetic field, reaching ~3s at 1T.QN/Quantum NanoscienceApplied Science