Universal Vectorial and Ultrasensitive Nanomechanical Force Field Sensor

Miniaturization of force probes into nanomechanical oscillators enables ultrasensitive investigations of forces on dimensions smaller than their characteristic length scale. Meanwhile it also unravels the force field vectorial character and how its topology impacts the measurement. Here we expose an ultrasensitive method to image 2D vectorial force fields by optomechanically following the bidimensional Brownian motion of a singly clamped nanowire. This novel approach relies on angular and spectral tomography of its quasi frequency-degenerated transverse mechanical polarizations: immersing the nanoresonator in a vectorial force field does not only shift its eigenfrequencies but also rotate eigenmodes orientation as a nano-compass. This universal method is employed to map a tunable electrostatic force field whose spatial gradients can even take precedence over the intrinsic nanowire properties. Enabling vectorial force fields imaging with demonstrated sensitivities of attonewton variations over the nanoprobe Brownian trajectory will have strong impact on scientific exploration at the nanoscale

Carbon Stocks and Fluxes in Tropical Lowland Dipterocarp Rainforests in Sabah, Malaysian Borneo

Deforestation in the tropics is an important source of carbon C release to the atmosphere. To provide a sound scientific base for efforts taken to reduce emissions from deforestation and degradation (REDD+) good estimates of C stocks and fluxes are important. We present components of the C balance for selectively logged lowland tropical dipterocarp rainforest in the Malua Forest Reserve of Sabah, Malaysian Borneo. Total organic C in this area was 167.9 Mg C ha−1±3.8 (SD), including: Total aboveground (TAGC: 55%; 91.9 Mg C ha−1±2.9 SEM) and belowground carbon in trees (TBGC: 10%; 16.5 Mg C ha−1±0.5 SEM), deadwood (8%; 13.2 Mg C ha−1±3.5 SEM) and soil organic matter (SOM: 24%; 39.6 Mg C ha−1±0.9 SEM), understory vegetation (3%; 5.1 Mg C ha−1±1.7 SEM), standing litter (<1%; 0.7 Mg C ha−1±0.1 SEM) and fine root biomass (<1%; 0.9 Mg C ha−1±0.1 SEM). Fluxes included litterfall, a proxy for leaf net primary productivity (4.9 Mg C ha−1 yr−1±0.1 SEM), and soil respiration, a measure for heterotrophic ecosystem respiration (28.6 Mg C ha−1 yr−1±1.2 SEM). The missing estimates necessary to close the C balance are wood net primary productivity and autotrophic respiration

Immunity Traits in Pigs: Substantial Genetic Variation and Limited Covariation

BACKGROUND: Increasing robustness via improvement of resistance to pathogens is a major selection objective in livestock breeding. As resistance traits are difficult or impossible to measure directly, potential indirect criteria are measures of immune traits (ITs). Our underlying hypothesis is that levels of ITs with no focus on specific pathogens define an individual's immunocompetence and thus predict response to pathogens in general. Since variation in ITs depends on genetic, environmental and probably epigenetic factors, our aim was to estimate the relative importance of genetics. In this report, we present a large genetic survey of innate and adaptive ITs in pig families bred in the same environment. METHODOLOGY/PRINCIPAL FINDINGS: Fifty four ITs were studied on 443 Large White pigs vaccinated against Mycoplasma hyopneumoniae and analyzed by combining a principal component analysis (PCA) and genetic parameter estimation. ITs include specific and non specific antibodies, seric inflammatory proteins, cell subsets by hemogram and flow cytometry, ex vivo production of cytokines (IFNα, TNFα, IL6, IL8, IL12, IFNγ, IL2, IL4, IL10), phagocytosis and lymphocyte proliferation. While six ITs had heritabilities that were weak or not significantly different from zero, 18 and 30 ITs had moderate (0.1<h2≤0.4) or high (h2>0.4) heritability values, respectively. Phenotypic and genetic correlations between ITs were weak except for a few traits that mostly include cell subsets. PCA revealed no cluster of innate or adaptive ITs. CONCLUSIONS/SIGNIFICANCE: Our results demonstrate that variation in many innate and adaptive ITs is genetically controlled in swine, as already reported for a smaller number of traits by other laboratories. A limited redundancy of the traits was also observed confirming the high degree of complementarity between innate and adaptive ITs. Our data provide a genetic framework for choosing ITs to be included as selection criteria in multitrait selection programmes that aim to improve both production and health traits

Electron probe microanalysis of carbon containing steels at a high spatial resolution

Whether it be inclusions, precipitates, segregation at grain boundaries, heterogeneous distribution of phases or constituents with complex morphologies, the development of new advanced high strength steels and manufacturing processes relies on the chemical characterization of their submicrometer features. More than any other alloying element, carbon plays a determining role, controlling the microstructure and the mechanical properties of these alloys. This work establishes acquisition and quantification strategies to measure the carbon concentration in low and high alloy steels by electron probe microanalysis at a high spatial resolution, circumventing many challenges associated with the measurement of this element. The optimal experimental conditions in terms of accuracy, precision and spatial resolution are determined using an optimization algorithm based on Monte Carlo simulations. Applications of the developed method for dual phase, transformation induced plasticity and twinning induced plasticity steels are presented.Out of the challenges, the carbon contamination and the quantification using soft X-rays are further elaborated in order to better understand their factors and mechanisms. The influence of the sample preparation, anti-contamination devices and experimental parameters on the carbonaceous deposits produced by a focused electron beam is studied based on specifically designed experiments and numerical simulations. The results support the hypothesis of the sample as the predominant source of contaminants, the low absorption and desorption rate of organic molecules on/from the sample surface, and the existence of a diffusion limited regime under the typical experimental conditions of a modern electron microprobe equipped with oil-free vacuum pumps.The quantification problems using soft X-rays, especially for the L3-M4,5 X-ray transition of first transition series metals, are investigated using Fe-Ni binary alloys. The effect of chemical bonding on the X-ray intensity is observed even for these metallic alloys. This work shows that the use of empirical mass attenuation coefficients and transition probability ratios, calculated from experimentally measured X-ray intensity \versus accelerating voltage curves, reduces the discrepancies between the experimental and calculated k-ratios, at least for this binary system

A pure Python implementation of the MSA / MAS / AMAS HyperDimensional Data File

pyHMSA is a pure Python implementation of the MSA / MAS / AMAS HyperDimensional Data File (HMSA, for short) specifications. This file format is intended to be a common exchange format for microscopy and microanalysis data. The library is designed to be minimalist, leaving post-processing of the data to the user’s script. The only dependency of pyHMSA is toNumPy, in order to represent the multi-dimensional data. pyHMSA is written to support both Python 2 and 3. The library is provided under the MIT license