In order to elucidate pressure-induced second superconducting phase (SC-II) in AxFe2−ySe2 (A = K, Rb, Cs, and Tl) having an intrinsic phase separation, we perform a detailed high-pressure ...magnetotransport study on the isoelectronic, phase-pure (Li1−xFex)OHFe1−ySe single crystals. Here we show that its ambient-pressure superconducting phase (SC-I) with a critical temperature Tc ≈ 40 K is suppressed gradually to below 2 K and an SC-II phase emerges above Pc ≈ 5 GPa with Tc increasing progressively to above 50 K up to 12.5 GPa. Our high-precision resistivity data uncover a sharp transition of the normal state from Fermi liquid for SC-I to non-Fermi liquid for SC-II phase. In addition, the reemergence of high-Tc SC-II is found to accompany with a concurrent enhancement of electron carrier density. Without structural transition below 10 GPa, the observed SC-II with enhanced carrier density should be ascribed to an electronic origin presumably associated with pressure-induced Fermi surface reconstruction.
Abstract Zero-field magnetization switching (ZFS) driven by current-induced spin–orbit torque (SOT) holds significant importance in spintronic applications. The introduction of a lateral asymmetric ...structure (LAS) through oblique deposition proves to be an effective strategy for breaking inversion symmetry, thereby enabling SOT-driven ZFS. However, the coexistence of wedge thickness structure and slanted columnar microstructure in the obliquely deposited films poses challenges in distinguishing their respective effects. In this study, we conducted a comparative investigation of the perpendicular magnetic properties and current-induced switching in W/Co 40 Fe 40 B 20 /MgO films by oblique sputtering of the W underlayer at a fixed tilting angle and at two opposite tilting angles with its wedge thickness compensated. We have found that the perpendicular magnetic properties of the Co 40 Fe 40 B 20 layer are significantly altered at large tilting angles, irrespective of whether the W wedge thickness is compensated. Notably, at a tilting angle of 50°, ZFS is realized for both the conventional oblique sample and the compensating oblique sample, with the switching polarity contingent on the final tilting direction of the W layer. We have identified a gradient in perpendicular magnetic anisotropy in these samples, attributed to the laterally varying roughness associated with the slanted columnar microstructure of the W underlayer. This study underscores the dominant role of microscopic LAS in obliquely deposited films in breaking SOT symmetry. Our research sheds light on the impact of the slanted columnar microstructure on the magnetic and magneto-transport properties of films, offering valuable insights for advancing spintronic device research.
The spread of rice black-streaked dwarf disease, which has emerged as a major problem on winter wheat and the two summer rice crops (early indica and late japonica) grown in central and southern ...Zhejiang province, China, is documented from 1995 to 2007. The late japonica crop suffered the most: up to 64 640 ha were affected with estimated losses of c. 120 000 t grain per year. Peak adult numbers of the small brown planthopper vector, Laodelphax striatellus, coincided with the seedling stages of both rice crops and the proportion of the insect population carrying virus increased during 1998-2005. Seedlings with three to four leaves were the most susceptible, whereas plants inoculated after the end of tillering developed few or no symptoms. Disease levels were strongly correlated with numbers of viruliferous vectors. In sowing-date experiments with both rice crops, the earliest sowings had the most disease and suffered the greatest yield losses. With the last sowing date (25 days after the first), there were almost no losses. There were yield losses of 0·80% for every 1% increase in disease incidence in early indica rice and rather more (0·92%) in the late japonica crop. There were large differences in susceptibility between cultivars, indicating the possibility, within currently available germplasm, of using more resistant cultivars to help contain the disease. Changes in cropping practice and in recent winter weather conditions have probably contributed to the emergence of the virus as a major pathogen in eastern China.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
Periodic mode changing in PSR J1048−5832 Yan, W M; Manchester, R N; Wang, N ...
Monthly Notices of the Royal Astronomical Society,
02/2020, Volume:
491, Issue:
4
Journal Article
Peer reviewed
Open access
ABSTRACT
By analysing the data acquired from the Parkes 64-m radio telescope at 1369 MHz, we report on the phase-stationary non-drift amplitude modulation observed in PSR J1048−5832. The ...high-sensitivity observations revealed that the central and trailing components of the pulse profile of this pulsar switch between a strong mode and a weak mode periodically. However, the leading component remains unchanged. Polarization properties of the strong and weak modes are investigated. Considering the similarity to mode changing, we argue that the periodic amplitude modulation in PSR J1048−5832 is periodic mode changing. The fluctuation spectral analysis showed that the modulation period is very short (∼2.1 s or 17P1), where P1 is the rotation period of the pulsar. We find that this periodic amplitude modulation is hard to explain by existing models that account for the periodic phenomena in pulsars like sub-pulse drifting.
ABSTRACT
We present the optical transmission spectrum of the hot Jupiter WASP-104b based on one transit observed by the blue and red channels of the Double Spectrograph (DBSP) at the Palomar 200-inch ...telescope and 14 transits observed by the MuSCAT2 four-channel imager at the 1.52-m Telescopio Carlos Sánchez. We also analyse 45 additional K2 transits, after correcting for the flux contamination from a companion star. Together with the transit light curves acquired by DBSP and MuSCAT2, we are able to revise the system parameters and orbital ephemeris, confirming that no transit timing variations exist. Our DBSP and MuSCAT2 combined transmission spectrum reveals an enhanced slope at wavelengths shorter than 630 nm and suggests the presence of a cloud deck at longer wavelengths. While the Bayesian spectral retrieval analyses favour a hazy atmosphere, stellar spot contamination cannot be completely ruled out. Further evidence, from transmission spectroscopy and detailed characterization of the host star’s activity, is required to distinguish the physical origin of the enhanced slope.
If neutrinos are their own antiparticles the otherwise-forbidden nuclear reaction known as neutrinoless double beta decay can occur. The very long lifetime expected for these exceptional events makes ...its detection a daunting task. In order to conduct an almost background-free experiment, the NEXT collaboration is investigating novel synthetic molecular sensors that may capture the Ba dication produced in the decay of certain Xe isotopes in a high-pressure gas experiment. The use of such molecular detectors immobilized on surfaces must be explored in the ultra-dry environment of a xenon gas chamber. Here, using a combination of highly sensitive surface science techniques in ultra-high vacuum, we demonstrate the possibility of employing the so-called Fluorescent Bicolor Indicator as the molecular component of the sensor. We unravel the ion capture process for these molecular indicators immobilized on a surface and explain the origin of the emission fluorescence shift associated to the ion trapping.
Oligodendrocyte precursor cells (OPCs) undergo an extensive and coordinated migration in the developing CNS, using the pre-formed scaffold of developed blood vessels as their physical substrate for ...migration. While OPC association with vasculature is critical for dispersal, equally important for permitting differentiation and proper myelination of target axons is their appropriate and timely detachment, but regulation of this process remains unclear. Here we demonstrate a correlation between the developmental formation of astrocytic endfeet on vessels and the termination of OPC perivascular migration. Ex vivo and in vivo live imaging shows that astrocyte endfeet physically displace OPCs from vasculature, and genetic abrogation of endfoot formation hinders both OPC detachment from vessels and subsequent differentiation. Astrocyte-derived semaphorins 3a and 6a act to repel OPCs from blood vessels at the cessation of their perivascular migration and, in so doing, permit subsequent OPC differentiation by insulating them from a maturation inhibitory endothelial niche.
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•Astrocyte endfoot placement terminates developmental OPC perivascular migration•Astrocyte-derived semaphorins 3a and 6a act to repel OPCs from blood vessels•OPC detachment from endothelium permits their subsequent differentiation
Su et al. find that the developmental placement of astrocyte endfeet on vessels controls the termination of widespread OPC perivascular migration. Astrocytes produce semaphorins 3a and 6a, which repel OPCs from the vasculature and permit their subsequent differentiation by releasing them from a maturation inhibitory endothelial niche.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
We report evidence for reconnection between colliding reconnection jets in a compressed current sheet at the center of a magnetic flux rope at Earth's magnetopause. The reconnection involved nearly ...symmetric Inflow boundary conditions with a strong guide field of two. The thin (2.5 ion-skin depth (d(sub i) width) current sheet (at approximately 12 d(sub i) downstream of the X line) was well resolved by MMS, which revealed large asymmetries in plasma and field structures in the exhaust. Ion perpendicular heating, electron parallel heating, and density compression occurred on one side of the exhaust, while ion parallel heating and density depression were shifted to the other side. The normal electric field and double out-of-plane (bifurcated) currents spanned almost the entire exhaust. These observations are in good agreement with a kinetic simulation for similar boundary conditions, demonstrating in new detail that the structure of large guide field symmetric reconnection is distinctly different from antiparallel reconnection.
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FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
AbstractObjectivesTo collect, appraise, select, and report the best available national estimates of cigarette consumption since 1970.DesignSystematic collection of comparable data.Setting and ...population71 of 214 countries for which searches for national cigarette consumption data were conducted, representing over 95% of global cigarette consumption and 85% of the world’s population.Main outcome measuresValidated cigarette consumption data covering 1970-2015 were identified for 71 countries. Data quality appraisal was conducted by two research team members in duplicate, with greatest weight given to official government sources. All data were standardised into units of cigarettes consumed per year in each country, a detailed accounting of data quality and sourcing was prepared, and all collected data and metadata were made freely available in an open access dataset.ResultsCigarette consumption fell in most countries over the past three decades but trends in country specific consumption were highly variable. For example, China consumed 2.5 million metric tonnes (MMT) of cigarettes in 2013, more than Russia (0.36 MMT), the United States (0.28 MMT), Indonesia (0.28 MMT), Japan (0.20 MMT), and the next 35 highest consuming countries combined. The US and Japan achieved reductions of more than 0.1 MMT from a decade earlier, whereas Russian consumption plateaued, and Chinese and Indonesian consumption increased by 0.75 MMT and 0.1 MMT, respectively. These data generally concord with modelled country level data from the Institute for Health Metrics and Evaluation and have the additional advantage of not smoothing year-over-year discontinuities that are necessary for robust quasi-experimental impact evaluations.ConclusionsBefore this study, publicly available data on cigarette consumption have been limited; they have been inappropriate for quasi-experimental impact evaluations (modelled data), held privately by companies (proprietary data), or widely dispersed across many national statistical agencies and research organisations (disaggregated data). This new dataset confirms that cigarette consumption has decreased in most countries over the past three decades, but that secular country specific consumption trends are highly variable. The findings underscore the need for more robust processes in data reporting, ideally built into international legal instruments or other mandated processes. To monitor the impact of the WHO Framework Convention on Tobacco Control and other tobacco control interventions, data on national tobacco production, trade, and sales should be routinely collected and openly reported.
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BFBNIB, CMK, NMLJ, NUK, PNG, SAZU, UL, UM, UPUK
Distant metastasis accounts for 90% of deaths from colorectal cancer (CRC). Genomic heterogeneity has been reported in various solid malignancies, but remains largely under-explored in metastatic CRC ...tumors, especially in primary to metastatic tumor evolution.
We conducted high-depth whole-exome sequencing in multiple regions of matched primary and metastatic CRC tumors. Using a total of 28 tumor, normal, and lymph node tissues, we analyzed inter- and intra-individual heterogeneity, inferred the tumor subclonal architectures, and depicted the subclonal evolutionary routes from primary to metastatic tumors.
CRC has significant inter-individual but relatively limited intra-individual heterogeneity. Genomic landscapes were more similar within primary, metastatic, or lymph node tumors than across these types. Metastatic tumors exhibited less intratumor heterogeneity than primary tumors, indicating that single-region sequencing may be adequate to identify important metastasis mutations to guide treatment. Remarkably, all metastatic tumors inherited multiple genetically distinct subclones from primary tumors, supporting a possible polyclonal seeding mechanism for metastasis. Analysis of one patient with the trio samples of primary, metastatic, and lymph node tumors supported a mechanism of synchronous parallel dissemination from the primary to metastatic tumors that was not mediated through lymph nodes.
In CRC, metastatic tumors have different but less heterogeneous genomic landscapes than primary tumors. It is possible that CRC metastasis is, at least partly, mediated through a polyclonal seeding mechanism. These findings demonstrated the rationale and feasibility for identifying and targeting primary tumor-derived metastasis-potent subclones for the prediction, prevention, and treatment of CRC metastasis.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
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