Frequency‐Dependent Moment Tensors of Induced Microearthquakes

Analysis of 984 induced microearthquakes from The Geysers geothermal reservoir in California reveals that the retrieved moment tensors depend on the frequency band of the inverted waveforms. The observed dependence is more significant for the percentages of the double‐couple, compensated linear vector dipole, and isotropic (ISO) components than for the focal mechanisms. The average root‐mean‐square of the moment tensors obtained in different frequency bands is correlated with spectra of ambient noise. The percentages of double‐couple and ISO components tend to decrease and increase with the upper cutoff frequency (fu), respectively. This suggests that shear rupture radiates energy preferentially in a lower frequency band and tensile rupture in a higher frequency band. Events displaying a strong increase of the ISO with fu are confined within the same depth interval as the injection points. This might be related to the strong thermoelastic effects in the vicinity of injection points that promote opening of small cracks adjacent to the main fractures

Spherulitic and rotational crystal growth of Quartz thin films

To obtain crystalline thin films of alpha-Quartz represents a challenge due to the tendency for the material towards spherulitic growth. Thus, understanding the mechanisms that give rise to spherulitic growth can help regulate the growth process. Here the spherulitic type of 2D crystal growth in thin amorphous Quartz films was analyzed by electron back-scatter diffraction (EBSD). EBSD was used to measure the size, orientation, and rotation of crystallographic grains in polycrystalline SiO(2) and GeO(2) thin films with high spatial resolution. Individual spherulitic Quartz crystal colonies contain primary and secondary single crystal fibers, which grow radially from the colony center towards its edge, and fill a near circular crystalline area completely. During their growth, individual fibers form so-called rotational crystals, when some lattice planes are continuously bent. The directions of the lattice rotation axes in the fibers were determined by an enhanced analysis of EBSD data. A possible mechanism, including the generation of the particular type of dislocation(s), is suggested

A novel MapReduce Lift association rule mining algorithm (MRLAR) for Big Data

Big Data mining is an analytic process used to dis-cover the hidden knowledge and patterns from a massive, com-plex, and multi-dimensional dataset. Single-processor's memory and CPU resources are very limited, which makes the algorithm performance ineffective. Recently, there has been renewed inter-est in using association rule mining (ARM) in Big Data to uncov-er relationships between what seems to be unrelated. However, the traditional discovery ARM techniques are unable to handle this huge amount of data. Therefore, there is a vital need to scal-able and parallel strategies for ARM based on Big Data ap-proaches. This paper develops a novel MapReduce framework for an association rule algorithm based on Lift interestingness measurement (MRLAR) which can handle massive datasets with a large number of nodes. The experimental result shows the effi-ciency of the proposed algorithm to measure the correlations between itemsets through integrating the uses of MapReduce and LIM instead of depending on confidence.Web of Science7315715

Crystallization of GeO2 thin films into α-quartz: From spherulites to single crystals

Piezoelectric quartz (SiO2) crystals are widely used in industry as oscillators. As a natural mineral, quartz and its relevant silicates are also of interest in geoscience and mineralogy. However, the nucleation and growth of quartz crystals are difficult to control and not fully understood. Here we report successful solid-state crystallization of thin film of amorphous GeO2 into quartz on various substrates, including Al2O3, MgAl2O4, MgO, LaAlO3 and SrTiO3. At relatively low annealing temperatures, the crystallization process is spherulitic: with fibers growing radially from the nucleation centers and the crystal lattice rotating along the growth direction with a linear dependence between the rotation angle and the distance to the core. For increasingly higher annealing temperatures, quartz crystals begin to form. The edges of the sample play an important role in facilitating nucleation followed by growth sweeping inward until the whole film is crystallized. Control of the growth allows single crystalline quartz to be synthesized, with crystal sizes of hundreds of microns achieved on sapphire substrates, which is promising for further piezoelectric applications. Our study reveals the complexity of the nucleation and growth process of quartz and provides insight for further studies

Vibronic coupling explains the ultrafast carotenoid-to-bacteriochlorophyll energy transfer in natural and artificial light harvesters

The initial energy transfer in photosynthesis occurs between the light-harvesting pigments and on ultrafast timescales. We analyze the carotenoid to bacteriochlorophyll energy transfer in LH2 Marichromatium purpuratum as well as in an artificial light-harvesting dyad system by using transient grating and two-dimensional electronic spectroscopy with 10 fs time resolution. We find that F\"orster-type models reproduce the experimentally observed 60 fs transfer times, but overestimate coupling constants, which leads to a disagreement with both linear absorption and electronic 2D-spectra. We show that a vibronic model, which treats carotenoid vibrations on both electronic ground and excited state as part of the system's Hamiltonian, reproduces all measured quantities. Importantly, the vibronic model presented here can explain the fast energy transfer rates with only moderate coupling constants, which are in agreement with structure based calculations. Counterintuitively, the vibrational levels on the carotenoid electronic ground state play a central role in the excited state population transfer to bacteriochlorophyll as the resonance between the donor-acceptor energy gap and vibrational ground state energies is the physical basis of the ultrafast energy transfer rates in these systems

Antiferromagnetic Ordering and Uncoupled Spins in CaFe₂O₄ Thin Films Probed by Spin Hall Magnetoresistance

CaFe2O4 is a uniaxial antiferromagnet displaying two coexisting magnetic orderings, A and B, characterized by ↑↑↓↓ and ↑↓↑↓ spin modulation, respectively, and the emergence of a net magnetization in a limited temperature range, which is not yet understood. The spin Hall magnetoresistance (SMR) is probed at the interface between Pt and CaFe2O4 and the crystallographic domain structure of thin film samples is exploited to perform single- and multi-domain scale measurements. The SMR response, upon rotating the magnetic field along three orthogonal planes, shows little effect of the strong magnetocrystalline and shape anisotropies. Together with the response to a varying magnetic field strength, the modulations in the SMR signal allow to extract two contributions: one corresponds to the long-range antiferromagnetic ordering, supporting a single ground state scenario; while the second contribution originates from uncompensated, non-interacting spins. These are expected to exist at the antiphase boundaries between antiferromagnetic domains. Here, it is shown that these are also uncoupled from the antiferromagnetic ordering. Nonetheless, the long range correlations that emerge in the proximity of the critical antiferromagnetic transition can give rise to ordering of the uncompensated spins and be responsible for the net magnetization observed in this antiferromagnet

Quasiparticle transport equation with collision delay. II. Microscopic Theory

For a system of non-interacting electrons scattered by neutral impurities, we derive a modified Boltzmann equation that includes quasiparticle and virial corrections. We start from quasiclassical transport equation for non-equilibrium Green's functions and apply limit of small scattering rates. Resulting transport equation for quasiparticles has gradient corrections to scattering integrals. These gradient corrections are rearranged into a form characteristic for virial corrections

Biochemical evidence for conformational variants in the anti-viral and pro-metastatic protein IFITM1

Interferon induced transmembrane proteins (IFITMs) play a dual role in the restriction of RNA viruses and in cancer progression, yet the mechanism of their action remains unknown. Currently, there is no data about the basic biochemical features or biophysical properties of the IFITM1 protein. In this work, we report on description and biochemical characterization of three conformational variants/oligomeric species of recombinant IFITM1 protein derived from an E. coli expression system. The protein was extracted from the membrane fraction, affinity purified, and separated by size exclusion chromatography where two distinct oligomeric species were observed in addition to the expected monomer. These species remained stable upon re-chromatography and were designated as “dimer” and “oligomer” according to their estimated molecular weight. The dimer was found to be less stable compared to the oligomer using circular dichroism thermal denaturation and incubation with a reducing agent. A two-site ELISA and HDX mass spectrometry suggested the existence of structural motif within the N-terminal part of IFITM1 which might be significant in oligomer formation. Together, these data show the unusual propensity of recombinant IFITM1 to naturally assemble into very stable oligomeric species whose study might shed light on IFITM1 anti-viral and pro-oncogenic functions in cells

Comparative characterization of two monoclonal antibodies targeting canine PD-1

Monoclonal antibodies targeting immune checkpoints have revolutionizedoncology. Yet, the effectiveness of these treatments varies significantly amongpatients, and they are associated with unexpected adverse events, includinghyperprogression. The murine research model used in drug development fails torecapitulate both the functional human immune system and the populationheterogeneity. Hence, a novel model is urgently needed to study theconsequences of immune checkpoint blockade. Dogs appear to be uniquelysuited for this role. Approximately 1 in 4 companion dogs dies from cancer, yetno antibodies are commercially available for use in veterinary oncology. Here wecharacterize two novel antibodies that bind canine PD-1 with sub-nanomolaraffinity as measured by SPR. Both antibodies block the clinically crucial PD-1/PDL1 interaction in a competitive ELISA assay. Additionally, the antibodies weretested with a broad range of assays including Western Blot, ELISA, flowcytometry, immunofluorescence and immunohistochemistry. The antibodiesappear to bind two distinct epitopes as predicted by molecular modeling andpeptide phage display. Our study provides new tools for canine oncologyresearch and a potential veterinary therapeutic

Coset Decompositions of Space Groups: Applications to Domain Structure Analysis

Left- and double-coset decompositions of space groups are systematically analysed by putting the emphasis on the introduction of special auxiliary groups. An algorithm is tailored to exploit the specific structure of space groups. The new results are, amongst others, an efficient alternative method to determine for space groups minimal sets of double-coset representatives and a general formula that gives the structure and number of left cosets that are contained in double cosets. Left-coset and double-coset decompositions of space groups are exploited in domain structure analysis