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We predict the 21-cm global signal and power spectra during the Epoch of Reionisation using the MERAXES semi-analytic galaxy formation and reionisation model, updated to include X-ray heating and thermal evolution of the intergalactic medium. Studying the formation and evolution of galaxies together with the reionisation of cosmic hydrogen using semi-analytic models (such as MERAXES) requires N-body simulations within large volumes and high mass resolutions. For this, we use a simulation of side-length $210~h^{-1}$ Mpc with $4320^3$ particles resolving dark matter haloes to masses of $5\times10^8~h^{-1}~M_\odot$. To reach the mass resolution of atomically cooled galaxies, thought to be the dominant population contributing to reionisation, at $z=20$ of $\sim 2\times10^7~h^{-1}~M_\odot$, we augment this simulation using the DARKFOREST Monte-Carlo merger tree algorithm (achieving an effective particle count of $\sim10^{12}$). Using this augmented simulation we explore the impact of mass resolution on the predicted reionisation history as well as the impact of X-ray heating on the 21-cm global signal and the 21-cm power spectra. We also explore the cosmic variance of 21-cm statistics within $70^{3}$ $h^{-3}$ Mpc$^3$ sub-volumes. We find that the midpoint of reionisation varies by $\Delta z\sim0.8$ and that the cosmic variance on the power spectrum is underestimated by a factor of $2-4$ at $k\sim 0.1-0.4$ Mpc$^{-1}$ due to the non-Gaussian nature of the 21-cm signal. To our knowledge, this work represents the first model of both reionisation and galaxy formation which resolves low-mass atomically cooled galaxies while simultaneously sampling sufficiently large scales necessary for exploring the effects of X-rays in the early Universe., Comment: 17 pages, 13 figures, revised and MNRAS accepted version

A flexible and low energy consumption artificial tactile neuron was proposed and experimentally demonstrated by integrating a dual network hydrogel-based sensor and a low power memristor.

A biomimetic nociceptor system with tactile perception was proposed and experimentally demonstrated by integrating a sensing paper with a threshold switching memristor.

Salinity stress severely affects plant growth and crop productivity. FCS-like zinc finger family genes (FLZ) play important roles in plant growth and stress responses. But most information of this family obtained was involved in sucrose signaling, limited function has been known in response to salinity stress. In this study, a novel FLZ gene TaFLZ2D has been isolated and characterized in response to salinity stress in wheat. TaFLZ2D was induced by both salinity stress and exogenous abscisic acid (ABA). Its transcript level was substantially higher in the salt resistant wheat cultivar SR3 than in its closely related but salt sensitive cultivar JN177. Transient expression in Nicotiana benthamiana leaf epidermal cells demonstrated TaFLZ2D was localized both in the cytoplasm membrane and nucleus. Constitutive expression of TaFLZ2D in Arabidopsis thaliana improved salinity stress tolerance and ABA sensitivity. Phenotype analysis under KCl and mannitol treatment demonstrated TaFLZ2D increased salinity stress tolerance mainly due to the superior ability to cope with ionic stress. TaFLZ2D over-expressing lines increased abscisic acid synthesis, peroxidase activity and reduced rate of water loss. Transcriptomic analysis demonstrated over-expression of TaFLZ2D regulated ABA-dependent and independent signaling pathway related genes expression and activated antioxidant related genes expression under normal condition and Ca2+ signaling related genes expression under NaCl treatmemt. Taken together, TaFLZ2D is a positive regulator of salinity stress tolerance, which contributes to salinity stress mainly through superior ability for ionic stress tolerance and ROS detoxification.

The transmission of Lyman-{\alpha} (Ly{\alpha}) in the spectra of distant quasars depends on the density, temperature, and ionization state of the intergalactic medium (IGM). Therefore, high-redshift (z > 5) Ly{\alpha} forests could be invaluable in studying the late stages of the epoch of reionization (EoR), as well as properties of the sources that drive it. Indeed, high-quality quasar spectra have now firmly established the existence of large-scale opacity fluctuations at z > 5, whose physical origins are still debated. Here we introduce a Bayesian framework capable of constraining the EoR and galaxy properties by forward-modelling the high-z Ly{\alpha} forest. Using priors from galaxy and CMB observations, we demonstrate that the final overlap stages of the EoR (when >95% of the volume was ionized) should occur at z < 5.6, in order to reproduce the large-scale opacity fluctuations seen in forest spectra. However, it is the combination of patchy reionization and the inhomogeneous UV background that produces the longest Gunn-Peterson troughs. Ly{\alpha} forest observations tighten existing constraints on the characteristic ionizing escape fraction of galaxies, with the combined observations suggesting f_{\rm esc} \approx 7^4_3%, and disfavoring a strong evolution with the galaxy's halo (or stellar) mass., Comment: 19 pages, 11 figures, submitted to MNRAS, comments are welcome

In order to enhance the sensing performance of isopropanol (IPA) vapor at room temperature (RT), a conducting polymer of polypyrrole (PPy) was employed to modify the ordered silicon nanowires (SiNWs). The loose structure of SiNWs which has the advantage of forming the structure of SiNWs uniformly coated by PPy was obtained via a dual-metal-assisted chemical etching (MACE) process. Vapor chemical polymerization of the pyrrole monomer (Py) was employed to prepare ultrathin PPy film uniformly functionalized SiNWs array, i.e., PPy@SiNWs. The results exhibit that an ultrathin PPy shell with thickness of 10 nm is wrapped on the surface of a loose SiNWs array forming perfect core-shell structure. Comparative investigations on the IPA-sensing properties of the PPy@SiNWs, SiNWs and PPy were carried out at RT. It shows that the as-formed PPy@SiNW sensor exhibits about a sevenfold response enhancement to 100 ppm IPA gas compared to the bare SiNWs. Moreover, the PPy@SiNW shows an acceptable stability, with a response attenuation of 8.9% observed within 33 days. The gas sensing results confirm that the PPy decoration can improve the sensing response and stability of the SiNW-based sensor.

The productivity of wheat, like that of most crop species, is adversely affected by soil salinity, so the identification of genes contributing to the salinity tolerance is an important priority for crop improvement. This study focuses on TaHSP17.6, a gene which encodes a salt and abcisic acid (ABA) inducible class I small molecular heat shock protein. Its transcription level was higher in a salinity tolerant wheat cultivar SR3 than in its less tolerant, but closely related cultivar JN177. The constitutive expression of TaHSP17.6 in Arabidopsis thaliana boosted the plants’ tolerance to salt stress and decreased their sensitivity to exogenously supplied ABA. Compared to wild type plants, the transgenic plants, when challenged with either salinity or ABA, developed a greater number of lateral roots, and their leaves accumulated more proline and have a higher activity of the antioxidant enzyme peroxidase. The transgenic leaves were superior to wild type ones with respect to their ability to maintain their hydration when detached from the plant. The product of TaHSP17.6 is proposed to contribute to the tolerance of osmotic and oxidative stress in an ABA-dependent manner. TaHSP17.6 is proposed as a candidate gene for engineering salinity tolerance in wheat.

Two-dimensional ultrathin tin monosulfide (SnS) nanoflakes have shown promise for gas-sensing applications thanks to their excellent lattice elasticity and superior anti-oxidation beyond black phosphorus. However when operating at room temperature (RT), both their gas-sensing response and detection limit are extremely subject to their low surface adsorption activity. In this work, the Mn atom with a local magnetic moment was selected to dope into the SnS lattice to boost the surface adsorption activation by introducing magnetic dipole inducement. The Mn-substituted SnS (Mn–SnS) showed unique hierarchical nanoflowers featuring nanoflake-assembled deep pores. On the grounds of this distinctive architecture and the doping-promotion effect, a fabricated Mn–SnS sensor exhibited a 3.35 times enhancement in response to 25 ppm acetone and much faster recovery characteristic in comparison to pure SnS, with a low detection limit of 500 ppb at RT. Based on adsorption fitting with the Langmuir isothermal model and calculations of the Gibbs free energy and electronic structure, the sensitive capability of Mn–SnS toward rarefied acetone and the enhanced response performances were demonstrated to originate from the physico-chemical synchronous adsorption of monolayer acetone molecules, as well as from the strong p–d orbital hybridization between the adsorbed acetone and Mn atom. Further, the rapid desorption characteristic of the acetone molecule on the Mn–SnS surface is the first-ever presumed based on DFT calculations and fitting equations by proposing a springback effect of the Mn atom in the Mn–SnS monolayer.

Silicon nanowires (SiNWs) array is a promising gas sensitive material featured as room-temperature response and compatibility of modern semiconductor technology. Towards breath diagnosis applications, a dual-functionalized SiNWs-based sensor (APTES&Ag@SiNWs) capable of rarefied acetone detection at high humidity level was developed based on the co-modification of 3-aminopropyl-triethoxylsilane (APTES) and nanoparticles of Ag. The SiNWs array was fabricated via metal assistant chemical etching (MACE) process and Ag nanoparticles modification was one-step achieved conveniently from MACE-produced Ag dendrites during SiNWs etching. In the APTES&Ag@SiNWs sensor, molecular functionalization of APTES could achieve obvious response promotion due to the active terminal amino groups of APTES for acetone molecule adsorption, while the modified Ag nanoparticles serve as wet centers to gather the adsorbed water molecules and then weaken the adverse effect of water adsorption on gas adsorption and response at high humidity. Resultantly, the on-chip sensor based on the dual-functionalized APTES&Ag@SiNWs array is revealed highly effective for acetone-sensing at room temperature and high humidity ambient (up to 85%RH). In particular, the as-developed APTES&Ag@SiNWs sensor shows linear response with the acetone concentration increasing from 1 to 4 ppm at 80%RH. The unique sensing characteristic makes the co-modified sensor promising in noninvasive diagnosis of diabetes via breath sensing. Finally, the moisture resistance analysis of the modified Ag is preformed based on first-principles calculations and meanwhile the contribution of APTES molecular functionalization on response enhancement is clarified.

Exploration of flexible tactile sensors with high sensitivity that can imitate the perception functions (tactile sensing and pain sensing) of human skin is the main force in the realization of electronic skin. The research of electronic skin with the function of pain perception is of great significance in the field of biomimetic robot and treatment of patients losing the pain sensation ability of their skin. Herein, to broaden the application field of traditional electronic skin, we demonstrate a biomimetic and highly sensitive tactile sensor for realization of sensory functionalities of human skin. The structure of our sensor mimics the surface of the tentacles of tentacled snakes, which are strikingly sensitive mechanoreceptors. We design a tentacle-inspired flexible sensor by sandwiching the convex dielectric layer of PDMS/MXene microarrays between two flexible electrodes. It is found that the bioinspired sensor exhibits a high sensitivity of 3.61 kPa−1, a fast response time of 29 ms and a satisfactory stability, ensuring the ability in monitoring physiological signals. Finally, we present the application of the sensor for finger bending, international Morse code detection, and artery pulse detection. By presetting the pain thresholds of different areas of skin in a program, the sensor can identify and distinguish pressure data that exceed the pain threshold, realizing the detection of pain. In addition, it can be further applied on robot skins to assess the risk level of the working environment by monitoring its pressure data.

X-rays from High-Mass X-ray Binaries (HMXBs) are likely the main source of heating of the intergalactic medium (IGM) during Cosmic Dawn (CD), before the completion of reionization. This Epoch of Heating (EoH; $z\sim 10-15$) should soon be detected via the redshifted 21-cm line from neutral hydrogen, allowing us to indirectly study the properties of HMXBs in the unseen, first galaxies. Low-redshift observations, as well as theoretical models, imply that the integrated X-ray luminosity to star formation rate of HMXBs ($L_{\rm X}/{\rm SFR}$) should increase in metal-poor environments, typical of early galaxies. Here we study the impact of the metallicity ($Z$) dependence of $L_{\rm X}/{\rm SFR}$ during the EoH. For our fiducial models, galaxies with star formation rates of order $10^{-3} - 10^{-1}$ $M_\odot$ yr$^{-1}$ and metallicities of order $10^{-3} - 10^{-2}$ $Z_\odot$ are the dominant contributors to the X-ray background (XRB) during this period. Different $L_{\rm X}/{\rm SFR}$-$Z$ relations result in factors of $\sim$ 3 differences in these ranges, as well as in the mean IGM temperature and the large-scale 21-cm power, at a given redshift. We compute mock 21-cm observations adopting as a baseline a 1000h integration with the upcoming Square Kilometer Array (SKA), for two different $L_{\rm X}/{\rm SFR}$-$Z$ relations. We perform inference on these mock observations using the common simplification of a constant $L_{\rm X}/{\rm SFR}$, finding that constant $L_{\rm X}/{\rm SFR}$ models can recover the IGM evolution of the more complicated $L_{\rm X}/{\rm SFR}$-$Z$ simulations only during the EoH. At $z

We present a new investigation of the intergalactic medium (IGM) near reionization using dark gaps in the Lyman-$\beta$ (Ly$\beta$) forest. With its lower optical depth, Ly$\beta$ offers a potentially more sensitive probe to any remaining neutral gas compared to commonly used Ly$\alpha$ line. We identify dark gaps in the Ly$\beta$ forest using spectra of 42 QSOs at $z_{\rm em}>5.5$, including new data from the XQR-30 VLT Large Programme. Approximately $40\%$ of these QSO spectra exhibit dark gaps longer than $10h^{-1}{\rm Mpc}$ at $z\simeq5.8$. By comparing the results to predictions from simulations, we find that the data are broadly consistent both with models where fluctuations in the Ly$\alpha$ forest are caused solely by ionizing ultraviolet background (UVB) fluctuations and with models that include large neutral hydrogen patches at $z, Comment: 17 pages, 13 figures, accepted for publication in ApJ. The Figure set and machine readable table are available at https://ydzhuastro.github.io/lyb.html

The presence of excess scatter in the Ly-$\alpha$ forest at $z\sim 5.5$, together with the existence of sporadic extended opaque Gunn-Peterson troughs, has started to provide robust evidence for a late end of hydrogen reionisation. However, low data quality and systematic uncertainties complicate the use of Ly-$\alpha$ transmission as a precision probe of reionisation's end stages. In this paper, we assemble a sample of 67 quasar sightlines at $z>5.5$ with high signal-to-noise ratios of $>10$ per $\leq 15$ km s$^{-1}$ spectral pixel, relying largely on the new XQR-30 quasar sample. XQR-30 is a large program on VLT/X-Shooter which obtained deep (SNR $>20$ per pixel) spectra of 30 quasars at $z>5.7$. We carefully account for systematics in continuum reconstruction, instrumentation, and contamination by damped Ly-$\alpha$ systems. We present improved measurements of the mean Ly-$\alpha$ transmission over $4.93.5 \sigma$). Our results indicate that reionisation-related fluctuations, whether in the UVB, residual neutral hydrogen fraction, and/or IGM temperature, persist in the intergalactic medium until at least $z=5.3$ ($t=1.1$ Gyr after the Big Bang). This is further evidence for a late end to reionisation., Comment: Accepted for publication in MNRAS. Full measurement datasets are available on the first author's website

Correlations between black holes and their host galaxies provide insight into what drives black hole-host co-evolution. We use the Meraxes semi-analytic model to investigate the growth of black holes and their host galaxies from high redshift to the present day. Our modelling finds no significant evolution in the black hole-bulge and black hole-total stellar mass relations out to a redshift of 8. The black hole-total stellar mass relation has similar but slightly larger scatter than the black hole-bulge relation, with the scatter in both decreasing with increasing redshift. In our modelling the growth of galaxies, bulges and black holes are all tightly related, even at the highest redshifts. We find that black hole growth is dominated by instability-driven or secular quasar-mode growth and not by merger-driven growth at all redshifts. Our model also predicts that disc-dominated galaxies lie on the black hole-total stellar mass relation, but lie offset from the black hole-bulge mass relation, in agreement with recent observations and hydrodynamical simulations., Comment: 14 pages, 11 figures. Accepted for publication in MNRAS

Layered double hydroxides (LDHs) have been acknowledged as potential gas sensing materials owing to their large specific surface area and compositional flexibility. In this work, highly sensitive LDHs-based nanocomposite of In(OH)3/ZnAlIn-LDHs was synthesized via hydrothermal growth of hierarchical ZnAlIn-LDHs and synchronous modification of single-crystalline nanoparticles of In(OH)3. The achieved In(OH)3/ZnAlIn-LDHs shows three-dimensional (3D) hierarchical architecture, with discrete In(OH)3 nanoparticles attachment on the nanosheet surface. The hierarchical ZnAlIn-LDHs forms loose 3D sensitive skeleton facilitating easy gas diffusion; additional In(OH)3 nanoparticles modification on LDHs nanosheets induces heterojunction effect capable of further enhancement of gas-sensing response. The gas-sensing measurements reveal that the achieved In(OH)3/ZnAlIn-LDHs nanocomposite is more sensitive to NO2 with rapid dynamic characteristic in comparison to the single components. At room temperature, the In(OH)3 modified ZnAlIn-LDHs can response ultra rarefied NO2 of 2.5 ppb with response of 35.4%. The significantly enhanced sensing response for the nanocomposite of In(OH)3/ZnAlIn-LDHs could attribute to the co-modulation of unique hierarchical microstructure, In-doping in LDHs layers and heterojunction effect between LDHs and the modified In(OH)3 nanoparticles.