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The evolution of melt ponds on Arctic sea ice in summer is one of the main factors that affect sea-ice albedo and hence the polar climate system. Due to the different spectral properties of open water, melt pond and sea ice, the melt pond fraction (MPF) can be retrieved using a fully constrained least-squares algorithm, which shows a high accuracy with root mean square error ~0.06 based on the validation experiment using WorldView-2 image. In this study, the evolution of ponds on first-year and multiyear ice in the Canadian Arctic Archipelago was compared based on Sentinel-2 and Landsat 8 images. The relationships of pond coverage with air temperature and albedo were analysed. The results show that the pond coverage on first-year ice changed dramatically with seasonal maximum of 54%, whereas that on multiyear ice changed relatively flat with only 30% during the entire melting period. During the stage of pond formation, the ponds expanded rapidly when the temperature increased to over 0°C for three consecutive days. Sea-ice albedo shows a significantly negative correlation (R = −1) with the MPF in melt season and increases gradually with the refreezing of ponds and sea ice.
In order to assess late prehistoric human responses to climate change in the Western Loess Plateau (WLP), we investigated 13,567 charred plant seeds and 19 radiocarbon (14C) dates obtained from 41 late prehistoric sites in the upper Wei River valley. Based on these new dating results as well as their cultural attributes, these sites could be confidently divided into four chronological phases (Phase 1: Late Yangshao and Majiayao culture; Phase 2: Qijia culture; Phases 3 and 4: Siwa culture) but a significant gap was identified at ca. 3600–3000 cal yr BP in this region. Comparison of this interval to high-resolution paleoclimate records from Tianchi Lake suggests it could be attributed to the dramatic drop in temperature at this time. Accordingly, archaeobotanical evidence with a refined chronology shows the adoption of cold-tolerant subsistence cereal grains such as barley on the NETP (Northeast Tibetan Plateau). Drawing from various lines of knowledge (chronology, palaeoclimate, archaeobotany, and archaeology), it is reasonable to conclude that, even when confronting a similar magnitude of climate change, local human societies could vary tremendously. Different subsistence strategies were brought in by the trans-Eurasia culture exchange of prehistoric times.
Arsenopyrite (FeAsS) and realgar (As4S4) are two common arsenic minerals that often cause serious environmental issues. Centralised treatment of arsenic-containing tailings can reduce land occupation and save management costs. The current work examined the remediation schemes of tailings from Hunan Province, China, where by different tailings containing arsenopyrite and realgar were blended with exogenous slag zero valence iron (ZVI). Introducing Fe-oxidising bacteria (Acidithiobacillus ferrooxidans) recreates a biologically oxidative environment. All bioleaching experiments were done over three stages, each for 7 days and the solid phase of all tests was characterised by scanning electron microscopy, X-ray diffraction, Fourier-transform infrared spectroscopy, X-ray photoelectron spectroscopy and selective extraction analyses. The results showed that the mixture group reduced arsenic release by 72.9–74.7% compared with the control group. The addition of 0.2 g ZVI clearly decreased arsenic release, and the addition of 4.0 g ZVI led to the lowest arsenic release among all tests. The decrease of arsenic released from the tailings was due to the adsorption and uptake of arsenic by secondary iron-containing minerals and Fe–As(V) secondary mineralisation. The addition of large amounts of ZVI reduced the arsenic detected in the amorphous Fe precipitates. Therefore, a low cost and integrated strategy to reduce arsenic release from tailings is to mix two typical tailings and apply exogenous slag ZVI, which can apply to the in situ remediation of two kinds or more arsenic-containing tailings.
Many academic studies use fixed preannouncement event days (e.g., -20,-42, or -63) to measure takeover premiums. In this paper, we show that the use of traditional fixed windows generates premiums that are underestimated by as much as 8 percentage points. This downward bias is especially severe for transactions with long processes (e.g., target-initiated deals). We take account of this bias by hand collecting deal initiation dates and show that using these dates results in measured premiums that give contradictory conclusions to those found in existing literature. We also offer guidance for measuring premiums if hand collecting data is impractical.
Silver/titanium dioxide (Ag/TiO2) membranes were successfully deposited on poly(sulfone amide) substrates by direct current magnetron sputtering and radio frequency magnetron sputtering techniques with pure silver (Ag) and TiO2 targets. The prepared membranes were systematically characterized by scanning electron microscopy X-ray diffraction, insulation tests, and Fourier transform infrared spectrometry. The dependence of the main sputtering parameters on optical and thermal properties of the film was investigated by an orthogonal analysis method. Optimal parameters of fabricate Ag/TiO2 membranes with better comprehensive performances could be obtained ultimately. The infrared reflection rate and temperature difference of the Ag/TiO2 film deposited with the optimized parameters were 81.6% and 90 °C, respectively. The high infrared reflection and excellent thermal conductivity properties of the Ag/TiO2 composite membrane make it a promising candidate for thermal insulating coatings on fabrics, and can be used for the development of high-performance protective garments in the future.
The pathophysiology of obsessive-compulsive disorder (OCD) remains unclear despite extensive neuroimaging work on the disorder. Exposure to medication and comorbid mental disorders can confound the results of OCD studies. The goal of this study was to explore differences in brain functional connectivity (FC) within the cortico-striato-thalamo-cortical (CSTC) loop of drug-naïve and drug-free OCD patients and healthy controls (HCs).
A total of 29 drug-naïve OCD patients, 22 drug-free OCD patients, and 25 HCs matched on age, gender and education level underwent functional magnetic resonance imaging scanning at resting state. Seed-based connectivity analyses were conducted among the three groups. The Yale Brown Obsessive Compulsive Scale and clinical inventories were used to assess the clinical symptoms.
Compared with HCs, the drug-naïve OCD patients had reduced FC within the limbic CSTC loop. In the drug-naïve OCD participants, we also found hyperconnectivity between the supplementary motor area and ventral and dorsal putamen (p < 0.05, corrected for multiple comparisons).
Exposure to antidepressants such as selective serotonin reuptake inhibitors may affect the function of some brain regions. Future longitudinal studies could help to reveal the pharmacotherapeutic mechanisms in these loops.
Barnyardgrass [Echinochloa crus-galli (L.) P. Beauv.] is acknowledged to be the most troublesome weed in rice fields in Anhui and Jiangsu provinces of China. It cannot be effectively controlled using certain acetolactate synthase (ALS)-inhibiting herbicides, including penoxsulam. Echinochloa crus-galli samples with suspected resistance to penoxsulam were collected to identify the target site–based mechanism underlying this resistance. Populations AXXZ-2 and JNRG-2 showed 33- and 7.3-fold resistance to penoxsulam, respectively, compared with the susceptible JLGY-3 population. Cross-resistance to other ALS inhibitors was reported in AXXZ-2 but not in JNRG-2, and occasionally showed higher sensitivity than JLGY-3. In vitro ALS activity assays revealed that penoxsulam concentrations required to inhibit 50% of ALS activity were 11 and 5.2 times greater in AXXZ-2 and JNRG-2, respectively, than in JLGY-3. DNA and predicted amino acid sequence analyses of ALS revealed Ala-205-Val and Ala-122-Gly substitutions in AXXZ-2 and JNRG-2, respectively. Our results indicate that these substitutions in ALS are at least partially responsible for resistance to penoxsulam.
Current available methods to detect cow milk adulteration or accidental contamination of goat milk are both laborious and time consuming. The aim of this technical research communication was to develop a simple, rapid, specific and sensitive method for quantitative detection of cow milk in goat milk. A competitive lateral flow immunoassay (LFIA) strip was developed using a specific monoclonal antibody (mAb) labeled with colloidal gold nanoparticles (GNPs) for specifically binding to cow milk casein. The detection limit of this rapid detection was 0.07% of cow milk in goat milk, providing equal specificity and higher sensitivity when compared with a commercial enzyme-linked immunosorbent assay (ELISA). These result suggest that the established rapid GNPs-LFIA strip could be used for monitoring cow milk adulteration/contamination of goat milk.
The Chinese Great Famine caused widespread starvation in 1959–1961. Its long-term association with depressive symptoms has not been studied.
To estimate the burden of depressive symptoms and the association of famine exposure with depressive symptoms.
The China Health and Retirement Longitudinal Study is a nationwide representative survey of 17 708 Chinese adults aged ≥45. Propensity score matching and modified Poisson regression were used to evaluate the association between self-reported famine exposure in early life and depressive symptoms among the overall participants. Such associations were also assessed by developmental stage using modified Poisson regression and logistic regression.
The prevalence of depressive symptoms was 26.2% (95% CI 25.1–27.3%) in 2011. As defined by loss of family members because of starvation, 11.6% (95% CI 10.1–13.1%) of this population experienced severe famine. When compared with participants who did not experience starvation, those who had experienced severe famine during fetal, mid-childhood, young-teenage and early-adulthood stages had 1.87 (95% CI 1.36–2.55), 1.54 (95% CI 1.23–1.94), 1.47 (95% CI 1.09–2.00) and 1.77 (95% CI 1.42–2.21) times higher odds of having depressive symptoms in late adulthood, respectively. The first two trimesters of pregnancy were a critical time window during the fetal stage when severe famine had a stronger association with depressive symptoms. Famine during infant, toddler, preschool or teenage stages was not associated with depressive symptoms. Overall, famine contributed to 13.6% of the depressive symptom burden in this population.
The Chinese Great Famine contributed substantially to the burden of depressive symptoms in China.
The wetting of Cu–19Ni–5Al alloy on Ni-coated WC–8Co substrates with different coating thicknesses was investigated, and the brazing of Ni-coated WC–8Co to SAE1045 steel was performed by using the Cu–19Ni–5Al alloy as the filler metal. All the Cu–19Ni–5Al/Ni-coated WC–8Co systems present excellent wettability with a final contact angle of ∼10°. The thicknesses of the β + γ phase enriched with Co, Ni, and Al at the two joint interfaces increase and decrease with the Ni coating thickness, brazing temperature, and holding time increasing, respectively. The joint shear strength increases first and then decreases with the increase of Ni coating thickness, brazing temperature, or holding time. The maximum joint shear strength of ∼328 MPa is obtained while Ni plating for 90 min and brazing at 1210 °C × 5 min.
We conducted a systematic search for periodically varying quasars, which are predicted manifestations of sub-pc supermassive black hole binaries (SMBHBs), in the Pan-STARRS1 Medium Deep Survey (PS1 MDS). Since the normal variability of quasars can also mimic periodicity over a small number of cycles, we have extended the temporal baseline by monitoring the candidates with the Discovery Channel Telescope and the Las Cumbres Observatory telescopes. We have also adopted a more rigorous method to evaluate the significance of the periodic candidates, by considering in the light curves a “red noise” background modeled as the Damped Random Walk process. While none of the candidates can be resolved by the current pulsar timing arrays (PTAs) as individual gravitational wave sources, the Large Synoptic Survey Telescope is capable of finding more periodic candidates, some of which are likely to be detected by the PTA experiment with the Square Kilometre Array.
H3PW12O40/polymethylmethacrylate (PMMA)/polycaprolactam (PA6) nanofibrous membrane with a sandwich structure was prepared by electrospinning. Characterization with Fourier transformation infrared spectroscopy (FT-IR), energy-dispersive x-ray spectroscopy (EDX), and x-ray photoelectron spectroscopy (XPS) indicated that H3PW12O40 has been successfully loaded into the upper and bottom layers of the sandwich membrane and its Keggin structure was not destroyed. The photocatalytic efficiency of the sandwich membranes were much higher (≥87.2%) than that of H3PW12O40 only (15.6%) and H3PW12O40/PMMA composite nanofibrous membrane (11.6%) in the degradation of methyl orange (MO) under ultraviolet irradiation. It may be caused by two factors: one was the photoreduction mechanism induced by the electron donating from PA6 to H3PW12O40, the other was the double contact area between H3PW12O40 and MO due to the sandwich structure of the laminated membrane. What is noteworthy is that the sandwich membranes were stable in water, so that they could be easily separated from the aqueous MO solution and reused without appreciable losses in photocatalytic activity after three photocatalytic cycles. In view of this, H3PW12O40/PMMA/PA6 sandwich nanofibrous membrane is promising as a photocatalyst to remove organic pollutants from practical wastewater.
Supermassive black hole binaries (SMBHBs) should be an inevitable consequence of the hierarchical growth of massive galaxies through mergers and the strongest sirens of gravitational waves (GWs) in the cosmos. Yet, their direct detection has remained elusive due to the compact (sub-parsec) orbital separations of gravitationally bound SMBHBs. Here we exploit a theoretically predicted signature of SMBHBs in the time domain. We have begun a systematic search for SMBHB candidates in the Pan-STARRS1 Medium Deep Survey (MDS) and reported our first significant detection of such a candidate from our pilot study of MD09 in Liu et al. (2015). Our candidate PSO J334.2028+01.4075 has a detected period of 542 days, varying persistently over the available baseline. From its archival spectrum, we estimated the black hole mass of the z = 2.06 quasar to be ∼1010 M⊙. The inferred ∼7 Rs binary separation therefore puts this candidate in the regime of GW-dominated orbital decay, opening up the exciting possibility of finding GW sources detectable by pulsar timing arrays (PTAs) in a wide-field optical synoptic survey.
The mineralogy of evaporites from the Lewis Cliff ice tongue (LCIT), Antarctica, and their mineral stabilities and transformation behaviours under different temperature and relative humidity (RH) conditions have been evaluated to elucidate formation mechanism(s). A variety of sodium (Na)-rich evaporite minerals were documented using RH-controlled powder X-ray diffraction (XRD) methods including Na-sulfates (mirabilite and thenardite), Na-carbonate/bicarbonates (nahcolite, occasional trona and natron) and Na-borates (qilianshanite and borax). Mirabilite begins to dehydrate to thenardite, and natron to trona and natrite when exposed to room temperature, even when maintained at RH values similar to those measured at the LCIT (50–70%). The boron-mineral qilianshanite was discovered for the first time in Antarctica within the evaporite mounds. The mirabilite-rich mounds are deduced to have formed via a freezing/sublimation process that occurred in glacial or subglacial bodies of water supplied by glacial tills containing microbially oxidized sulfate ions. The needle-like nahcolite crystals growing on the exteriors of the mounds suggest a dissolution/precipitation process involving atmospheric CO2 and water. The co-existence of nahcolite and boron-bearing minerals indicates the presence of a Na+-, HCO3-- and boron-bearing alkaline brine, which produces qilianshanite as a secondary mineral by reaction of nahcolite and borax in atmospheric CO2 and H2O.
The effect of high-grain (HG) feeding on caecal bacterial microbiota composition and fermentation and mucosa health is largely unknown. In the present study, ten male goats were randomly assigned to either a group fed a hay diet (0 % grain; n 5) or a group fed a HG diet (65 % grain; n 5) to characterise the changes in the composition of the bacterial community and mucosal morphology in the caecum. After 7 weeks of feeding, the HG diet decreased the caecal pH (P< 0·001) and increased (P< 0·001 to P< 0·004) the caecal digesta concentrations of total volatile fatty acids and lipopolysaccharide (LPS). Pyrosequencing of the 16S ribosomal RNA gene revealed that HG feeding increased (P= 0·001 to P= 0·009) the abundance of predominant genera Turicibacter and Clostridium in the caecal lumen and in the caecal mucosa and decreased (P< 0·001 to P< 0·009) the proportion of Bacteroides in the lumen and Mucispirillum in the mucosa compared with the hay diet. Furthermore, the HG diet-fed goats exhibited intense epithelial damage and up-regulation (P< 0·001 to P< 0·025) of the relative mRNA expression of IL-1β, IL-6, IL-12 and interferon-γ (IFN-γ) in the caecal mucosa. The correlation analysis revealed that alterations in caecal pH, LPS concentration and mucosa-associated microbiota abundance during HG feeding might partly contribute to local inflammation. Collectively, these results provide insight into the adaptive response of caecal bacterial populations to HG feeding in goats and reveal that the fermentable substrates that flow into the caecum may cause dramatic alterations in microbial compositions and play a significant role in caecal dysfunction.
The objective of this work is to reveal the relationship between the molecular structure and shape-memory property of a hydro-epoxy resin system. The system is prepared using hydro-epoxy, menthane diamine (MDA), and poly(propylene glycol) diglycidyl ether (PPGDGE) with different molecular weights. By keeping the PPGDGE content constant, the crosslink density of the shape-memory hydro-epoxy resin system can be changed by varying the molecular weight of PPGDGE. The results indicate that the glass transition temperature (Tg) and rubber modulus (Er) decrease as the crosslink density decreases. The crosslink density has little influence on shape recovery ratio (Rr). Full recovery can be observed after only several minutes when the temperature is equal to or above Tg. However, the crosslink density has a profound effect on the shape fixity ratio (Rf). If the crosslink density is too low, the shape fixity ratio of shape-memory hydro-epoxy resin would not reach 100%.
This study spatially quantifies hydrological ecosystem services and the production of ecosystem services at the watershed scale. We also investigate the effects of stressors such as land use change, climate change, and choices in land management practices on production of ecosystem services and their values. We demonstrate the approach in the Beaver River watershed in Rhode Island. Our key finding is that choices in land use and land management practices create tradeoffs across multiple ecosystem services and the extent of these tradeoffs depends considerably on the scenarios and ecosystem services being compared.
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