Some anomalies of mesosphere/lower thermosphere parameters during the recent solar minimum

The recent solar minimum has been characterized by an anomalous strong decrease of thermospheric density since 2005. Here we analyze anomalies of mesosphere/lower thermosphere parameters possibly connected with this effect. In particular, nighttime mean LF reflection heights measured at Collm, Germany, show a very strong decrease after 2005, indicating a density decrease. This decrease is also visible in mean meteor heights measured with VHF meteor radar at Collm. This density decrease is accompanied by an increase of gravity wave (GW) amplitudes in the upper mesosphere and a decrease in the lower thermosphere. On the decadal scale, GWs are negatively correlated with the background zonal wind, but this correlation is modulated in the course of the solar cycle, indicating the combined effect of GW filtering and density decrease

Low-noise quantum frequency conversion in a monolithic bulk ppKTP cavity

Interfacing the different building blocks of a future large scale quantum network will demand efficient and noiseless frequency conversion of quantum light. Nitrogen-vacancy (NV) centers in diamond are a leading candidate to form the nodes of such a network. However, the performance of a suitable converter remains a bottleneck, with existing demonstrations severely limited by parasitic noise arising at the target telecom wavelength. Here, we demonstrate a new platform for efficient low-noise quantum frequency conversion based on a monolithic bulk ppKTP cavity and show its suitability for the conversion of 637 nm single photons from NV centers in diamond to telecommunication wavelengths. By resonantly enhancing the power of an off-the-shelf pump laser, we achieve an internal conversion efficiency of $(72.3\pm 0.4)\%$ while generating only (110\pm 4) \mbox{ kHz/nm} noise at the target wavelength without the need for any active stabilization. This constitutes a 5-fold improvement in noise over existing state-of-the-art single-step converters at this wavelengths. We verify the almost ideal preservation of non-classical correlations by converting photons from a spontaneous parametric down-conversion source and moreover show the preservation of time-energy entanglement via Franson interferometry.Comment: 7 pages, 6 figures, 2 table

Messung von Impulsflüssen in der Mesosphäre / unteren Thermosphäre mit dem SKiYMET Meteorradar in Collm – Methode und erste Ergebnisse

Schwerewellen transportieren Energie und Impuls aus den unteren in die oberen Atmosphärenschichten. Impulsflüsse und ihre Divergenz beschreiben dabei die Kopplung der Wellen mit der mittleren Zirkulation. Mit einer Methode von Hocking (2005) können Varianzen und Schwerewellenimpulsflüsse in der Mesosphäre / unteren Thermosphäre mit einem All-Sky Interferometric (SKiYMET) Meteorradar bestimmt werden. Diese Methode wurde auf die Datensätze des Meteorradars in Collm (51.3°N,13.0°E) angewandt. Erste Ergebnisse für die Varianzen und Impulsflüsse sowie speziell für die Höhenprofile des vertikalen Flusses zonalen Impulses im Jahresgang und die Untersuchung dessen auf periodische Schwankungen werden hier vorgestellt.Gravity waves transport energy and momentum from the lower to the upper atmosphere. Momentum fluxes and their divergence describe the coupling of the waves with the background circulation. By using a method presented by Hocking (2005), wind variances and gravity wave momentum fluxes in the mesosphere/lower thermosphere can be determined with an all-sky interferometric (SKiYMET) meteor radar. This method has been applied to the data sets of the meteor radar at Collm (51.3°N,13.0°E). First results for the variances and momentum fluxes as well as for the height profiles of the vertical flux of zonal momentum, its seasonal cycle and periodic variations are presented

Enabling Aqueous Processing of Ni Rich Layered Oxide Cathode Materials by Addition of Lithium Sulphate

Aqueous processing of Ni rich layered oxide cathode materials is a promising approach to simultaneously decrease electrode manufacturing costs, while bringing environmental benefits by substituting the state of the art often toxic and costly organic processing solvents. However, an aqueous environment remains challenging due to the high reactivity of Ni rich layered oxides towards moisture, leading to lithium leaching and Al current collector corrosion because of the resulting high pH value of the aqueous electrode paste. Herein, a facile method was developed to enable aqueous processing of LiNi0.8Co0.1Mn0.1O2 NCM811 by the addition of lithium sulfate Li2SO4 during electrode paste dispersion. The aqueously processed electrodes retained 80 amp; 8201; of their initial capacity after 400 cycles in NCM811 graphite full cells, while electrodes processed without the addition of Li2SO4 reached 80 amp; 8201; of their capacity after only 200 cycles. Furthermore, with regard to electrochemical performance, aqueously processed electrodes using carbon coated Al current collector outperformed reference electrodes based on state of the art production processes involving N methyl 2 pyrrolidone as processing solvent and fluorinated binders. The positive impact on cycle life by the addition of Li2SO4 stemmed from a formed sulfate coating as well as different surface species, protecting the NCM811 surface against degradation. Results reported herein open a new avenue for the processing of Ni rich NCM electrodes using more sustainable aqueous route

Dipolar spin ice regime proximate to an all-in-all-out N\'{e}el ground state in the dipolar-octupolar pyrochlore Ce2_2Sn2_2O7_7

The dipolar-octupolar (DO) pyrochlores, R$_2$M$_2$O$_7$ (R = Ce, Sm, Nd), are key players in the search for realizable novel quantum spin liquid (QSL) states as a large parameter space within the DO pyrochlore phase diagram is theorized to host QSL states of both dipolar and octupolar nature. We present neutron diffraction measurements on newly synthesized hydrothermally-grown Ce$_2$Sn$_2$O$_7$ powders that show a broad signal at low scattering vectors, reminiscent of a dipolar spin ice. This is strikingly different from previous neutron diffraction on powder samples grown from solid-state synthesis, which found diffuse scattering at high scattering vectors associated with magnetic octupoles. This raises the question about subtle crystalline structural differences and in particular the potential role of disorder that is present in the different samples. We quantify any differences through complementary neutron structure refinement and atomic PDF measurements but detect no oxidation or other crystallographic disorder in the hydrothermally-grown samples. To interpret the new diffuse scattering, we characterize the exchange interaction parameters in the near-neighbor XYZ model Hamiltonian associated with DO pyrochlores by fitting quantum numerical linked cluster expansions (NLCE) to heat capacity and magnetic susceptibility measurements, and classical Monte Carlo calculations to the diffuse neutron diffraction of the newly synthesized Ce$_2$Sn$_2$O$_7$ samples. This places Ce$_2$Sn$_2$O$_7$'s ground state within the ordered dipolar all-in-all-out (AIAO) N\'{e}el phase with quantum Monte-Carlo calculations showing a transition to long-range order at temperatures below those accessed experimentally. We conclude that new hydrothermally-grown Ce$_2$Sn$_2$O$_7$ samples host a finite-temperature proximate dipolar spin ice phase, above the expected transition to AIAO N\'{e}el order.Comment: 11 pages, 11 figure

Use of the Spencer Technique on Collegiate Baseball Players: Effect on Physical Performance and Self-Report Measures

Context: Repeated overhead throwing in baseball players alters range of motion (ROM), contributing to shoulder injury. The Spencer technique has been used, anecdotally, to reduce the effects of throwing-induced limitations in ROM. Objective: To quantify the effects of a single administration of the Spencer technique on the ROM and performance of collegiate baseball pitchers. Methods: Pitchers from the Seton Hill University men's baseball team were randomly assigned to 2 treatment groups: Spencer technique or sham therapy. The first week consisted of baseline outcome measurements (1 week before treatment), including ROM (flexion, extension, abduction, adduction, internal rotation, and external rotation) of the dominant throwing arm, 10 maximum velocity throws, and self-reported performance using the Kerlan-Jobe Orthopaedic Clinic Shoulder and Elbow Score (KJOC-SES). The second week consisted of pretreatment ROM measurement, followed by a single treatment and repeated measurement of all outcomes. Results: Of 16 players, 15 met inclusion criteria. An effect of training on ROM between weeks 1 and 2 for all players consisted of significantly decreased internal rotation (P=.02) and increased external rotation (P=.04). A differential effect of treatment was found on the mean difference in internal rotation after treatment, compared with the mean difference before treatment on the same day (P=.01). Additionally, a trend toward statistical significance for abduction (P=.08) was noted. Analyses reveal that these effects were caused by significant increases in the internal rotation and abduction for the Spencer group only (P=.02). All other analyses of ROM, as well as performance measured by maximum velocity throws and the KJOC-SES, revealed no differential effect of treatment. Conclusion: The results of this study support the use of the Spencer technique in counteracting the potentially negative effects of repeated throwing on internal rotation. However, a single administration did not affect functional ability in this study. Future studies of longer duration and including differing levels of play, injury status, and playing position will be needed to further evaluate the full potential of the Spencer technique in athletes who engage in repeated overhead arm movements

Quantum Spin Ice Response to a Magnetic Field in the Dipole-Octupole Pyrochlore Ce2_2Zr2_2O7_7

We report new heat capacity measurements on single crystal Ce$_2$Zr$_2$O$_7$ down to $\sim$ 0.1 K in a magnetic field along the $[1,\bar{1}, 0]$ direction. These new measurements show that the broad hump in the zero-field heat capacity moves higher in temperature with increasing field strength and is split into two humps by the $[1,\bar{1}, 0]$ field at $\sim$ 2 T. These separate features are due to the decomposition of the pyrochlore lattice into effectively decoupled chains for fields in this direction: one set of chains ($\alpha$-chains) is polarized by the field while the other ($\beta$-chains) remains free. Our theoretical modelling suggests that the $\beta$-chains are close to a critical state, with nearly-gapless excitations. We also report new elastic and inelastic neutron scattering measurements on single crystal Ce$_2$Zr$_2$O$_7$ in $[1, \bar{1}, 0]$ and $[0, 0, 1]$ magnetic fields at temperatures down to 0.03 K. The elastic scattering behaves consistently with the formation of independent chains for a $[1, \bar{1}, 0]$ field, while the $[0, 0, 1]$ field produces a single field-induced magnetic Bragg peak at $(0, 2, 0)$ and equivalent wavevectors, indicating a polarized spin ice for fields above $\sim$ 3 T. For both $[1, \bar{1}, 0]$ and $[0, 0, 1]$ fields, our inelastic neutron scattering results show an approximately-dispersionless continuum of scattering that increases in both energy and intensity with increasing field strength. By modelling the complete set of experimental data using numerical linked cluster and semiclassical molecular dynamics calculations, we demonstrate the dominantly multipolar nature of the exchange interactions in Ce$_2$Zr$_2$O$_7$ and the smallness of the parameter $\theta$ which controls the mixing between dipolar and octupolar degrees of freedom. These results support previous estimates of the microscopic exchange parameters.Comment: 20 pages, 10 figure

Insights into Electrolytic Pre Lithiation A Thorough Analysis Using Silicon Thin Film Anodes

Pre lithiation via electrolysis, herein defined as electrolytic pre lithiation, using cost efficient electrolytes based on lithium chloride LiCl , is successfully demonstrated as a proof of concept for enabling lithium ion battery full cells with high silicon content negative electrodes. An electrolyte for pre lithiation based on amp; 947; butyrolactone and LiCl is optimized using boron containing additives lithium bis oxalato borate, lithium difluoro oxalate borate and CO2 with respect to the formation of a protective solid electrolyte interphase SEI on silicon thin films as model electrodes. Reversible lithiation in Si Li metal cells is demonstrated with Coulombic efficiencies CEff of 95 96 for optimized electrolytes comparable to 1 m LiPF6 EC EMC 3 7. Formation of an effective SEI is shown by cyclic voltammetry and X ray photoelectron spectroscopy XPS . electrolytic pre lithiation experiments show that notable amounts of the gaseous product Cl2 dissolve in the electrolyte leading to a self discharge Cl2 Cl amp; 8722; shuttle mechanism between the electrodes lowering pre lithiation efficiency and causing current collector corrosion. However, no significant degradation of the Si active material and the SEI due to contact with elemental chlorine is found by SEM, impedance, and XPS. In NCM111 Si full cells, the capacity retention in the 100th cycle can be significantly increased from 54 to 78 by electrolytic pre lithiation, compared to reference cells without pre lithiation of S

Application of circulating cell-free tumor DNA profiles for therapeutic monitoring and outcome prediction in genetically heterogeneous metastatic melanoma

PURPOSE Circulating cell-free tumor DNA (ctDNA) reflects the heterogeneousspectrum of tumor-specific mutations, especially in systemic disease. We validated plasma-based assays that allow the dynamic quantitative detection of ctDNA as a prognostic biomarker for tumor load and prediction of therapy response in melanoma. MATERIALS and METHODS We analyzed plasma-derived ctDNA from a large training cohort (n = 96) of patients with advanced-stage melanoma, with assays for the BRAFV600E and NRASQ61 driver mutations as well as TERTC250T and TERTC228T promoter mutations. An independent patient cohort (n = 35) was used to validate the utility of ctDNA monitoring under mitogen-activated protein kinase–targeted or immune checkpoint therapies. RESULTS Elevated plasma ctDNA level at baseline was an independent prognostic factor of disease progression when compared with serum S100 and lactate dehydrogenase levels in multivariable analyses (hazard ratio [HR], 7.43; 95% CI, 1.01 to 55.19; P = .05). The change in ctDNA levels during therapy correlated with treatment response, where increasing ctDNA was predictive for shorter progression-free survival (eg, for BRAFV600EctDNA, HR, 3.70; 95% CI, 1.86 to 7.34; P < .001). Increasing ctDNA levels predicted disease progression significantly earlier than did routine radiologic scans (P < .05), with a mean lead time of 3.5 months. NRAS-mutant ctDNA was detected in a significant proportion of patients with BRAF-mutant tumors under therapy, but unexpectedly also at baseline. In vitro sensitivity studies suggested that this represents higher-than-expected intratumoral heterogeneity. The detection of NRASQ61 ctDNA in baseline samples of patients with BRAFV600E mutation who were treated with mitogen-activated protein kinase inhibitors significantly correlated with shorter progression-free survival (HR, 3.18; 95% CI, 1.31 to 7.68; P = .03) and shorter overall survival (HR, 4.08; 95% CI, 1.57 to 10.58; P = .01). CONCLUSION Our results show the potential role of ctDNA measurement as a sensitive monitoring and prediction tool for the early assessment of disease progression and therapeutic response in patients with metastaticmelanoma