Circulators are nonreciprocal circuit elements that are integral to technologies including radar systems, microwave communication transceivers, and the readout of quantum information devices. Their ...nonreciprocity arises from the interference of microwaves over the centimeter scale of the signal wavelength, in the presence of bulky magnetic media that breaks time-reversal symmetry. Here, we realize a completely passive on-chip microwave circulator with size 1/1000th the wavelength by exploiting the chiral, “slow-light” response of a two-dimensional electron gas in the quantum Hall regime. For an integrated GaAs device with 330μm diameter and about 1-GHz center frequency, a nonreciprocity of 25 dB is observed over a 50-MHz bandwidth. Furthermore, the nonreciprocity can be dynamically tuned by varying the voltage at the port, an aspect that may enable reconfigurable passive routing of microwave signals on chip.
Animal experiments remain essential to understand the fundamental mechanisms underpinning malignancy and to discover improved methods to prevent, diagnose and treat cancer. Excellent standards of ...animal care are fully consistent with the conduct of high quality cancer research. Here we provide updated guidelines on the welfare and use of animals in cancer research. All experiments should incorporate the 3Rs: replacement, reduction and refinement. Focusing on animal welfare, we present recommendations on all aspects of cancer research, including: study design, statistics and pilot studies; choice of tumour models (e.g., genetically engineered, orthotopic and metastatic); therapy (including drugs and radiation); imaging (covering techniques, anaesthesia and restraint); humane endpoints (including tumour burden and site); and publication of best practice.
Context.
The sub-Jovian, or Neptunian, desert is a previously identified region of parameter space where there is a relative dearth of intermediate-mass planets with short orbital periods.
Aims.
We ...present the discovery of a new transiting planetary system within the Neptunian desert, NGTS-14.
Methods.
Transits of NGTS-14Ab were discovered in photometry from the Next Generation Transit Survey (NGTS). Follow-up transit photometry was conducted from several ground-based facilities, as well as extracted from TESS full-frame images. We combine radial velocities from the HARPS spectrograph with the photometry in a global analysis to determine the system parameters.
Results.
NGTS-14Ab has a radius that is about 30 per cent larger than that of Neptune (0.444 ± 0.030
R
Jup
) and is around 70 per cent more massive than Neptune (0.092 ± 0.012
M
Jup
). It transits the main-sequence K1 star, NGTS-14A, with a period of 3.54 days, just far away enough to have maintained at least some of its primordial atmosphere. We have also identified a possible long-period stellar mass companion to the system, NGTS-14B, and we investigate the binarity of exoplanet host stars inside and outside the Neptunian desert using
Gaia
.
Arbuscular mycorrhizal (AM) fungi are biotrophic symbionts colonizing the majority of land plants, and are of major importance in plant nutrient supply. Their diversity is suggested to be an ...important determinant of plant community structure, but the influence of host‐plant and environmental factors on AM fungal community in plant roots is poorly documented. Using the terminal restriction fragment length polymorphism (T‐RFLP) strategy, the diversity of AM fungi was assessed in 89 roots of three grass species (Agrostis capillaris, Festuca rubra, Poa pratensis) that co‐occurred in the same plots of a field experiment. The impact of different soil amendments (nitrogen, lime, nitrogen and lime) and insecticide application on AM fungal community was also studied. The level of diversity found in AM fungal communities using the T‐RFLP strategy was consistent with previous studies based on clone libraries. Our results clearly confirm that an AM fungal host‐plant preference exists, even between different grass species. AM communities colonizing A. capillaris were statistically different from the others (P < 0.05). Although grass species evenness changed in amended soils, AM fungal community composition in roots of a given grass species remained stable. Conversely, in plots where insecticide was applied, we found higher AM fungal diversity and, in F. rubra roots, a statistically different AM fungal community.
Abstract
Previous examinations of fully convective M-dwarf stars have highlighted enhanced rates of nanoflare activity on these distant stellar sources. However, the specific role the convective ...boundary, which is believed to be present for spectral types earlier than M2.5V, plays on the observed nanoflare rates is not yet known. Here, we utilize a combination of statistical and Fourier techniques to examine M-dwarf stellar lightcurves that lie on either side of the convective boundary. We find that fully convective M2.5V (and later subtypes) stars have greatly enhanced nanoflare rates compared with their pre-dynamo mode-transition counterparts. Specifically, we derive a flaring power-law index in the region of 3.00 ± 0.20, alongside a decay timescale of 200 ± 100 s for M2.5V and M3V stars, matching those seen in prior observations of similar stellar subtypes. Interestingly, M4V stars exhibit longer decay timescales of 450 ± 50 s, along with an increased power-law index of 3.10 ± 0.18, suggesting an interplay between the rate of nanoflare occurrence and the intrinsic plasma parameters, e.g., the underlying Lundquist number. In contrast, partially convective (i.e., earlier subtypes from M0V to M2V) M-dwarf stars exhibit very weak nanoflare activity, which is not easily identifiable using statistical or Fourier techniques. This suggests that fully convective stellar atmospheres favor small-scale magnetic reconnection, leading to implications for the flare-energy budgets of these stars. Understanding why small-scale reconnection is enhanced in fully convective atmospheres may help solve questions relating to the dynamo behavior of these stellar sources.
ABSTRACT We investigate the evolution of far-IR CO emission from protostars observed with Herschel/PACS for 50 sources from the combined sample of HOPS and DIGIT Herschel key programs. From the ...uniformly sampled spectral energy distributions, whose peaks are well sampled, we computed the , , and for these sources to search for correlations between far-IR CO emission and protostellar properties. We find a strong and tight correlation between far-IR CO luminosity ( ) and the bolometric luminosity ( ) of the protostars with . We, however, do not find a strong correlation between and protostellar evolutionary indicators, and . FIR CO emission from protostars traces the currently shocked gas by jets/outflows, and far-IR CO luminosity, , is proportional to the instantaneous mass-loss rate, . The correlation between and , then, is indicative of instantaneous tracking instantaneous . The lack of a correlation between and evolutionary indicators and suggests that and, therefore, do not show any clear evolutionary trend. These results are consistent with mass accretion/ejection in protostars being episodic. Taken together with the previous finding that the time-averaged mass-ejection/accretion rate declines during the protostellar phase, our results suggest that the instantaneous accretion/ejection rate of protostars is highly time variable and episodic, but the amplitude and/or frequency of this variability decreases with time such that the time-averaged accretion/ejection rate declines with system age.
Cancer stem cell (CSC) biology and the epithelial-to-mesenchymal transition (EMT) are thought to be mechanistically linked and may be key components of cancer development and progression. However, ...stimuli that induce EMT and CSC-like features ('stemness') are poorly defined. We and others have shown that the inflammatory cytokine oncostatin-M (OSM) mediates phenotypic changes in breast cancer that are consistent with EMT and dedifferentiation, including enhanced migration and loss of hormone receptors. In this study, we have expanded on these prior observations to determine whether OSM is a cell-extrinsic driver of EMT and/or stemness. OSM stimulation of the luminal breast cancer cell lines MCF7 and T47D induced EMT features including loss of membranous E-cadherin and induction of snail and slug expression. OSM treatment markedly enhanced the formation of mammospheres (up to 20-fold, P<0.001), which displayed high expression of the pluripotency factor SOX2. The proportion of cells with a CD44(high)CD24(-/low) phenotype was similarly increased by OSM (P<0.001). OSM-induced mammosphere formation and CD44(high)CD24(-/low) induction was dependent on PI3K signalling. In silico analysis of human breast tumours (from a publicly available data set, n=322) confirmed that co-expression of a PI3K transcriptional signature, but not MAPK or STAT3 signatures, was necessary to detect an association between OSMR and poor prognosis. Assessment of a second in silico data set (n=241 breast tumours) confirmed a significant relationship between OSMR, markers of EMT and CSCs, and chemotherapy resistance. Direct analysis of mRNA expression by RT-PCR in a third cohort (n=72 breast tumours) demonstrated that high expression of OSM is associated positively with indicators of EMT (SNAI1, P<0.001) and stemness (SOX2, P<0.05). Our data suggest for the first time that OSM may promote a clinically relevant EMT/CSC-like phenotype in human breast cancer via a PI3K-dependent mechanism.
A balanced t(1;11) translocation that transects the Disrupted in schizophrenia 1 (DISC1) gene shows genome-wide significant linkage for schizophrenia and recurrent major depressive disorder (rMDD) in ...a single large Scottish family, but genome-wide and exome sequencing-based association studies have not supported a role for DISC1 in psychiatric illness. To explore DISC1 in more detail, we sequenced 528 kb of the DISC1 locus in 653 cases and 889 controls. We report 2718 validated single-nucleotide polymorphisms (SNPs) of which 2010 have a minor allele frequency of <1%. Only 38% of these variants are reported in the 1000 Genomes Project European subset. This suggests that many DISC1 SNPs remain undiscovered and are essentially private. Rare coding variants identified exclusively in patients were found in likely functional protein domains. Significant region-wide association was observed between rs16856199 and rMDD (P=0.026, unadjusted P=6.3 × 10(-5), OR=3.48). This was not replicated in additional recurrent major depression samples (replication P=0.11). Combined analysis of both the original and replication set supported the original association (P=0.0058, OR=1.46). Evidence for segregation of this variant with disease in families was limited to those of rMDD individuals referred from primary care. Burden analysis for coding and non-coding variants gave nominal associations with diagnosis and measures of mood and cognition. Together, these observations are likely to generalise to other candidate genes for major mental illness and may thus provide guidelines for the design of future studies.
Background. Diagnosis of malaria relies on parasite detection by microscopy or antigen detection; both fail to detect low-density infections. New tests providing rapid, sensitive diagnosis with ...minimal need for training would enhance both malaria diagnosis and malaria control activities. We determined the diagnostic accuracy of a new loop-mediated amplification (LAMP) kit in febrile returned travelers. Methods. The kit was evaluated in sequential blood samples from returned travelers sent for pathogen testing to a specialist parasitology laboratory. Microscopy was performed, and then malaria LAMP was performed using Plasmodium genus and Plasmodium falciparum-speciñc tests in parallel. Nested polymerase chain reaction (PCR) was performed on all samples as the reference standard. Primary outcome measures for diagnostic accuracy were sensitivity and specificity of LAMP results, compared with those of nested PCR. Results. A total of 705 samples were tested in the primary analysis. Sensitivity and specificity were 98.4% and 98.1%, respectively, for the LAMP P. falciparum primers and 97.0% and 99.2%, respectively, for the Plasmodium genus primers. Post hoc repeat PCR analysis of all 15 tests with discrepant results resolved 4 results in favor of LAMP, suggesting that the primary analysis had underestimated diagnostic accuracy. Conclusions. Malaria LAMP had a diagnostic accuracy similar to that of nested PCR, with a greatly reduced time to result, and was superior to expert microscopy.
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