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Transfer learning deals with how systems can quickly adapt themselves to new situations, tasks and environments. It gives machine learning systems the ability to leverage auxiliary data and models to help solve target problems when there is only a small amount of data available. This makes such systems more reliable and robust, keeping the machine learning model faced with unforeseeable changes from deviating too much from expected performance. At an enterprise level, transfer learning allows knowledge to be reused so experience gained once can be repeatedly applied to the real world. For example, a pre-trained model that takes account of user privacy can be downloaded and adapted at the edge of a computer network. This self-contained, comprehensive reference text describes the standard algorithms and demonstrates how these are used in different transfer learning paradigms. It offers a solid grounding for newcomers as well as new insights for seasoned researchers and developers.
Melatonin treatment in adult cashmere goats can increase cashmere yield and improve cashmere fibre quality by inducing cashmere growth during cashmere non-growth period, of which time cashmere goats are in the mid and late stages of lactation. However, whether melatonin treatment in adult cashmere goats affects their offspring’s growth performance remains unknown. Therefore, the objectives of the current study were to determine the effects of melatonin treatment in adult cashmere goats on cashmere and milk production performance in dams and on hair follicle development and subsequent cashmere production in their offspring. Twenty-four lactating Inner Mongolian Cashmere goat dams (50 ± 2 days in milk, mean ± SD) and their single-born female offspring (50 ± 2 days old, mean ± SD) were randomly assigned to one of two groups supplemented with melatonin implants (MEL; n = 12) or without (CON; n = 12). The melatonin implants were subcutaneously implanted behind the ear at a dose of 2 mg/kg live weight on two occasions – 30 April and 30 June 2016. The results demonstrated that melatonin treatment in adult cashmere goats increased cashmere production and improved cashmere fibre quality as indicated by greater cashmere yield, longer cashmere fibre staple length, finer cashmere fibre diameter and thicker cashmere fibre density. The milk fat content was higher in MEL compared with CON cashmere goats. The daily yields of milk production, milk protein and milk lactose were lower in MEL compared with CON cashmere goats. Serum melatonin concentrations were greater, serum prolactin concentrations were lower and milk melatonin concentrations and yields were greater in MEL compared with CON cashmere goats. With regard to offspring, there were no differences in cashmere yield, fibre staple length, fibre diameter and fibre density at yearling combing, and the primary and secondary hair follicles population and maturation between treatments. In conclusion, melatonin treatment in adult cashmere goats during cashmere non-growth period is a practical and an effective way in cashmere industry as indicated by not only increasing cashmere yield and improving cashmere fibre quality in adult cashmere goat dams but also having no impairment in hair follicle development and the subsequent cashmere production in their single-born offspring.
We present detailed petrography, geochemistry and zircon U–Pb–Hf isotopes of the Mante Aobao granite porphyry in East Ujimqin Banner, Inner Mongolia, with the aim of determining its age and petrogenesis, important for understanding the early Palaeozoic tectonic evolution of the Xing’an–Mongolian Orogenic Belt. The Mante Aobao granite porphyry consists of plagioclase, quartz and minor biotite, but without amphibole. Zircon U–Pb analyses yield ages of 450 ± 1 Ma and 445 ± 2 Ma for the granite porphyry, indicating that it formed during Late Ordovician time. The granite porphyry is metaluminous to slightly peraluminous (aluminous saturation index A/CNK = 0.98–1.11) with high SiO2, K2O and Na2O concentrations and differentiation index (DI = 85–90). Chondrite-normalized rare earth element (REE) patterns display enrichment of light REEs (LREEs) with high ratios of (La/Yb)N and negative Eu anomalies. In the mantle-normalized multi-element variation diagrams, all samples are characterized by depletions of high-field-strength elements (HFSEs; Nb, Ta and Ti) and enrichments of large-ion lithophiles (LILEs; Rb, Th, U and K). These geochemical features indicate that the granite porphyry is a highly fractionated I-type granite and formed in a subduction-related setting. Zircon grains have positive εHf(t) values of +9.2 to +11.2, and TDM2(Hf) ages of 691–821 Ma, suggesting that the granite porphyry was generated by partial melting of Neoproterozoic juvenile crust with involvement of fractional crystallization during magmatic evolution. It is likely that underplating of mantle-derived magmas during Late Ordovician time provided the necessary heat to partially melt this juvenile crust. Combined with the regional geological data, we infer that the Mante Aobao granite porphyry was emplaced in an active continental margin setting that was probably related to the northwards subduction of the Paleo-Asian Plate beneath the South Mongolian Terrane along the Sonid Zuoqi–Xilinhot axis.
We established a mastitis model using exogenous infection of the mammary gland of Chinese Holstein cows with Staphylococcus aureus and extracted total RNA from S. aureus-infected and healthy mammary quarters. Differential expression of genes due to mastitis was evaluated using Affymetrix technology and results revealed a total of 1230 differentially expressed mRNAs. A subset of affected genes was verified via Q-PCR and pathway analysis. In addition, Solexa high-throughput sequencing technology was used to analyze profiles of miRNA in infected and healthy quarters. These analyses revealed a total of 52 differentially expressed miRNAs. A subset of those results was verified via Q-PCR. Bioinformatics techniques were used to predict and analyze the correlations among differentially expressed miRNA and mRNA. Results revealed a total of 329 pairs of negatively associated miRNA/mRNA, with 31 upregulated pairs of mRNA and 298 downregulated pairs of mRNA. Differential expression of miR-15a and interleukin-1 receptor-associated kinase-like 2 (IRAK2), were evaluated by western blot and luciferase reporter assays. We conclude that miR-15a and miR-15a target genes (IRAK2) constitute potential miRNA–mRNA regulatory pairs for use as biomarkers to predict a mastitis response.
The Ordovician–Silurian (O–S) transition was a critical interval in geological history. Multiple geochemical methods are used to explore the changes in oceanic environment. The Nd isotopic compositions in the Yangtze Sea are controlled by two sources: the continental erosion and the Panthalassa Ocean. High εNd(t) values during the Katian, late Hirnantian and Rhuddanian intervals are associated with the high sea level, which resulted in less terrestrial input based on the low Ti/Al and Zr/Al ratios. In contrast, low εNd(t) values during the early Hirnantian interval are related to the sea-level fall; in this case, the exposure of submarine highs and the growth of Yangtze Oldlands could lead to more continental materials being transported into the Yangtze Sea based on high Ti/Al and Zr/Al ratios. In addition, the negative εNd(t) excursion can also be attributed to the weak circulation between the Yangtze Sea and Panthalassa Ocean when sea level was low. Furthermore, the sea-level eustacy plays a significant role in the changes in redox water conditions. The redox indices, mainly UEF, Ce/Ce* and Corg/PT, across the O–S transition show a predominance of anoxic ocean over the Yangtze Sea during the Katian, late Hirnantian and Rhuddanian intervals, and an oxygenated episode was briefly introduced during the early Hirnantian period because of the fall in sea level. The Late Ordovician biotic crisis was marked by two-phase extinction events, and the change in sea level and redox chemistry may be the important kill mechanisms.
Systematic error is one of the major factors that affect positioning accuracy owing to the changeable and complex nature of seawater environments. Based on a Global Navigation Satellite System-acoustic intelligent buoys system, whose acoustic array consists of a series of surface buoys, a single-difference method for underwater dynamic positioning is proposed to eliminate systematic error. Positioning configuration optimisation was addressed using dilution of precision (DOP). A simulation of DOP proved that for the single-difference method, a radiation network with a centre-difference reference point was superior to a regular polygon network. The positioning experiment showed that the novel method could effectively eliminate systematic error, improving vertical positioning accuracy from a metre- to a decimetre scale.
Iron carbide (Fe1−xCx) thin films were successfully grown by plasma-enhanced atomic layer deposition (PEALD) using bis(N,N′-di-tert-butylacetamidinato)iron(II) as a precursor and H2 plasma as a reactant. Smooth and pure Fe1−xCx thin films were obtained by the PEALD process in a layer-by-layer film growth fashion, and the x in the nominal formula of Fe1−xCx is approximately 0.26. For the wide PEALD temperature window from 80 to 210 °C, a saturated film growth rate of 0.04 nm/cycle was achieved. X-ray diffraction and transition electron microscope measurements show that the films grown at deposition temperature 80–170 °C are amorphous; however, at 210 °C, the crystal structure of Fe7C3 is formed. The conformality and resistivity of the deposited films have also been studied. At last, the PEALD Fe1−xCx on carbon cloth shows excellent electrocatalytic performance for hydrogen evolution.
The microbiota–gut–brain axis, especially the microbial tryptophan (Trp) biosynthesis and metabolism pathway (MiTBamp), may play a critical role in the pathogenesis of major depressive disorder (MDD). However, studies on the MiTBamp in MDD are lacking. The aim of the present study was to analyze the gut microbiota composition and the MiTBamp in MDD patients.
We performed shotgun metagenomic sequencing of stool samples from 26 MDD patients and 29 healthy controls (HCs). In addition to the microbiota community and the MiTBamp analyses, we also built a classification based on the Random Forests (RF) and Boruta algorithm to identify the gut microbiota as biomarkers for MDD.
The Bacteroidetes abundance was strongly reduced whereas that of Actinobacteria was significantly increased in the MDD patients compared with the abundance in the HCs. Most noteworthy, the MDD patients had increased levels of Bifidobacterium, which is commonly used as a probiotic. Four Kyoto Encyclopedia of Genes and Genomes (KEGG) orthologies (KOs) (K01817, K11358, K01626, K01667) abundances in the MiTBamp were significantly lower in the MDD group. Furthermore, we found a negative correlation between the K01626 abundance and the HAMD scores in the MDD group. Finally, RF classification at the genus level can achieve an area under the receiver operating characteristic curve of 0.890.
The present findings enabled a better understanding of the changes in gut microbiota and the related Trp pathway in MDD. Alterations of the gut microbiota may have the potential as biomarkers for distinguishing MDD patients form HCs.
The present study was designed to investigate the in vivo biological processes of multivesicular bodies (MVBs) and exosomes in mitochondria-rich cells (MRCs), goblet cells (GCs), and absorptive cells (ACs) in turtle intestines during hibernation. The exosome markers, cluster of differentiation 63 (CD63) and tumor susceptibility gene 101 (TSG101), were positively expressed in intestinal villi during turtle hibernation. The distribution and formation processes of MVBs and exosomes in turtle MRCs, GCs, and ACs were further confirmed by transmission electron microscopy. During hibernation, abundantly secreted early endosomes (ees) were localized in the luminal and basal cytoplasm of the MRCs and ACs, and late endosomes (les) were dispersed with the supranuclear parts of the MRCs and ACs. Many “heterogeneous” MVBs were identified throughout the cytoplasm of the MRCs and ACs. Interestingly, the ees, les, and MVBs were detected in the cytoplasm of the GCs during hibernation; however, they were absent during nonhibernation. Furthermore, the exocytosis pathways of exosomes and autophagic vacuoles were observed in the MRCs, GCs, and ACs during hibernation. In addition, the number of different MVBs with intraluminal vesicles (ILVs) and heterogeneous endosome–MVB–exosome complexes was significantly increased in the MRCs, GCs, and ACs during hibernation. All these findings indicate that intestinal epithelial cells potentially perform a role in the secretion of MVBs and exosomes, which are essential for mucosal immunity, during hibernation.
Flexible electrode is an indispensable component of emerging portable, flexible, and wearable electronic devices. Although various flexible electrodes with different dimensions and functions have been explored, developing a new electrode material with excellent mechanical reliability and superior electrical performance remains a challenge. Here, a graphene-covered Cu composite electrode film with a total thickness of ∼100 nm is successfully fabricated onto a flexible polyimide substrate by means of a series of assembly methods including physical vapor deposition, chemical vapor deposition, and transfer technique. The composite electrode film on the flexible substrate exhibits evidently enhanced tensile strength, monotonic bending, and repeatedly bending fatigue reliability as well as electrical performance compared with that of the bared Cu film electrode. Such excellent mechanical performances are attributed to the role of the graphene coating in suppressing fatigue damage formation and preventing crack advance. It is expected that the chemical vapor-deposited graphene-covered Cu composite electrode would extend the potential ultrathin metal film electrode as the innovative electrode material for the next-generation flexible electronic devices.
Light-absorbing impurities (LAIs, e.g. black carbon (BC), organic carbon (OC), mineral dust (MD)) deposited on snow cover reduce albedo and accelerate its melting. Northern Xinjiang (NX) is an arid and semi-arid inland region, where snowmelt leads to frequent floods that have been a serious threat to local ecological security. There is still a lack of quantitative assessments of the effects of LAIs on snowmelt in the region. This study investigates spatial variations of LAIs in snow and its effect on snow albedo, radiative forcing (RF) and snowmelt across NX. Results showed that concentrations of BC, OC (only water-insoluble OC), MD ranged from 32 to 8841 ng g−1, 77 to 8568 ng g−1 and 0.46 to 236 µg g−1, respectively. Weather Research and Forecasting Chemistry model suggested that residential emission was the largest source of BC. Snow, Ice, and Aerosol Radiative modelling showed that the average contribution of BC and MD to snow albedo reduction was 17 and 3%, respectively. RF caused by BC significantly exceeded RF caused by MD. In different scenarios, changes in snow cover duration (SCD) caused by BC and MD decreased by 1.36 ± 0.61 to 6.12 ± 3.38 d. Compared with MD, BC was the main dominant factor in reducing snow albedo and SCD across NX.
An 8-week feeding experiment was conducted to investigate the effects of dl-methionine (Met) supplementation in a low-fishmeal diet on growth, key gene expressions of amino acid transporters and target of rapamycin (TOR) pathway in juvenile cobia, Rachycentron canadum. Seven isonitrogenous and isolipidic diets were formulated, containing 0·72, 0·90, 1·00, 1·24, 1·41, 1·63 and 1·86 % Met. Weight gain and specific growth rates increased gradually with Met levels of up to 1·24 % and then decreased gradually. In dorsal muscle, mRNA levels of ASCT2 in the 1·00 % Met group were significantly up-regulated compared with 0·72, 1·63, and 1·86 %. The insulin-like growth factor-I (IGF-I) mRNA levels in the dorsal muscle of fish fed 1·00 and 1·24 % Met were higher than those in fish fed other Met levels. In addition, fish fed 1·24 % Met showed the highest mRNA levels of TOR and phosphorylation of TOR on Ser2448. The phosphorylation of ribosomal p70-S6 kinase (S6K) on Ser371 in the dorsal muscle of fish fed 1·86 % Met was higher than those in the 0·72 % group. In conclusion, straight broken-line analysis of weight gain rate against dietary Met level indicates that the optimal Met requirement for juvenile cobia is 1·24 % (of DM, or 2·71 % dietary protein). Met supplementation in a low-fishmeal diet increased cobia growth via a mechanism that can partly be attributed to Met’s ability to affect the TOR/S6K signalling pathway by enhancing ASCT2 and IGF-I transcription in cobia dorsal muscle.
It is urgent to develop new antimalarial drugs with good therapeutic effects to address the emergence of drug resistance. Here, the artelinic acid-choline derivative (AD) was synthesized by dehydration reaction and esterification reaction, aimed to avoid the emergence of drug resistance by synergistic effect of artemisinins and choline derivative, which could compete with choline for rate-limiting enzymes in the phosphatidylcholine (PC) biosynthetic pathway. AD was formulated into liposomes (ADLs) by the thin-film hydration method. Efficacy of ADLs was evaluated by Peters 4-day suppression test. The suppression percentage against Plasmodium yoelii BY265 (PyBY265) in ADLs group was higher than those of positive control groups (dihydroartemisinin liposomes, P < 0.05) and other control groups (P ⩽ 0.05) at the doses of 4.4, 8.8, 17.6 µmol (kg·d)−1, respectively. The negative conversion fraction, recrudescence fraction and survival fraction of ADLs group were superior to other control groups. Pharmacokinetics in rats after intravenous injection suggested that ADLs exhibited higher exposure levels (indexed by area under concentration-time curve) than that of AD solution, artelinic acid liposomes or artelinic acid solution (P < 0.01). Taken together, ADLs exhibited promising antimalarial efficacy and pharmacokinetic characteristics.
The cao vit gibbon Nomascus nasutus, also known as eastern black crested gibbon, is categorized as Critically Endangered on the IUCN Red List and was considered one of the world's 25 most threatened primates. The only known population occurs along the border between China and Viet Nam. Accurate information on population size and dynamics is critical for the species’ conservation, but population surveys conducted in only one country may over- or underestimate total population size because the home ranges of cao vit gibbon groups often cross the international border. In 2007 and 2016 we conducted two collaborative transboundary censuses of the cao vit gibbon populations in the Trung Khanh Cao Vit Gibbon Species and Habitat Conservation Area in Viet Nam and the Bangliang Gibbon National Nature Reserve in China. The results showed a population size of 102–110 in 2007, which increased to 107–136 in 2016. Our results indicate that previous surveys conducted separately in Viet Nam and China underestimated the global population size of this species. According to our more comprehensive surveys, the gibbon population is increasing slowly. The gibbons and their habitat are legally protected in both countries. Hunting and charcoal making have not been reported in this area since 2007. As habitat carrying capacity is a limiting factor, habitat restoration is required. However, lack of funding to protect the cao vit gibbon remains a challenge.
We conducted active surveillance of acute respiratory viral infections (ARIs) among residents and healthcare personnel (HCP) at a long-term care facility during the 2015–2016 respiratory illness season. ARIs were observed among both HCP and patients, highlighting the importance of including HCP in surveillance programs.
The purpose of this paper is to establish some limit theorems of delayed averages for countable nonhomogeneous Markov chains. The definition of the generalized C-strong ergodicity and the generalized uniformly C-strong ergodicity for countable nonhomogeneous Markov chains is introduced first. Then a theorem about the generalized C-strong ergodicity and the generalized uniformly C-strong ergodicity for the nonhomogeneous Markov chains is established, and its applications to the information theory are given. Finally, the strong law of large numbers of delayed averages of bivariate functions for countable nonhomogeneous Markov chains is proved.
The kernel extreme learning machine (KELM) is more robust and has a faster learning speed when compared with the traditional neural networks, and thus it is increasingly gaining attention in hyperspectral image (HSI) classification. Although the Gaussian radial basis function kernel widely used in KELM has achieved promising classification performance in supervised HSI classification, it does not consider the underlying data structure of HSIs. In this paper, we propose a novel spectral-spatial KELM method (termed as MF-KELM) by incorporating the mean filtering kernel into the KELM model, which can properly compute the mean value of the spatial neighboring pixels in the kernel space. Considering that in the situation of limited training samples the classification result is very noisy, the spatial bilateral filtering information on spectral band-subsets is introduced to improve the accuracy. Experiment results show that our method outperforms other kernel functions based on KELM in terms of classification accuracy and visual comparison.
Anatase phase NOx/S6+–TiO2 (x= 0, 1) film with high solar-driven activity has been successfully prepared via electro-assisted oxidation processes. The morphological and structural properties of the film were characterized by scanning electron microscopy, transmission electron microscopy, X-ray photoelectron spectroscopy, and X-ray diffraction, while the optical property was detected by UV-vis-NIR absorption spectroscopy. The results showed that the NOx/S6+–TiO2 film was composed of “flower-like” microvoids structure and displayed broad and strong optical absorption at around 544 and 1500 nm. Transient photocurrent response, photoluminescence spectroscopy, and electrochemical impedance spectroscopy indicated that the generation and separation of photogenerated charges were significantly enhanced under simulated solar irradiation. The NOx/S6+–TiO2 film exhibited excellent photoelectrocatalytic activity for the degradation of methyl orange (MO), and the decoloration rate and TOC removal respectively reached 98.97 and 59.44% at 20 min under solar irradiation. The film still had good stability after reusing ten times. Furthermore, a possible mechanism of photoelectrocatalysis was suggested in MO degradation by using NOx/S6+–TiO2 film.
Hepatitis C virus (HCV) infection was frequent in human immunodeficiency virus (HIV) patients in Yunnan province. We studied the epidemic characteristics of HCV in HIV/HCV co-infected patients. Serum from 894 HIV-1 patients was collected, together with basic information and biochemical features. All samples were infected with HIV through injecting drug users (IDUs) and sexual transmission (ST). The NS5B gene was amplified and sequenced to affirm HCV genotype. In total, 202 HIV patients were co-infected with HCV, and most (81.19%) of co-infected patients were IDUs. Genotype 3b was predominant (37.62%) in these samples, and its frequency was similar in patients with IDU and ST. The frequencies of genotypes 1a, 1b, 3a, 6a, 6n, 2a and 6u were 3.96%, 16.34%, 23.76%, 6.93%, 10.40%, 0.50% and 0.50%, respectively. However, genotype 3a showed significantly different frequency in HCV patients with IDU and ST (P = 0.019). When HCV patients were divided into subgroups, the haemoglobin (HGB) level was significantly higher in patients with genotype 3a than in patients with 3b (P = 0.033), 6a (P = 0.006) and 6n (P = 0.007), respectively. Although no difference existed among HCV subgroups, HIV-viral load was identified to be positively correlated with the HGB level and CD4+ cells when dividing HCV/HIV co-infected persons into male and female groups. In conclusion, genotype 3b was the predominant HCV genotype in Yunnan HIV/HCV co-infected persons. The HGB level was higher in patients with genotype 3a than others. HIV-viral load was positively correlated with the HGB level and CD4+ cells in the male or female HCV-infected group.
In this work, a new reconfigurable discrete 1D beam-steering Fabry–Perot cavity antenna with enhanced radiation performance is presented. It consists of a probe-fed patch antenna printed on the ground plane and a reconfigurable metasurface acting as the upper partially reflective surface to realize beam steering. By utilizing 6 × 6 proposed reconfigurable unit cells on the superstrate, the beam-steering angle can be effectively enhanced from ±7° to ±17° with fewer active elements and a much simpler biasing network. The proposed antenna was fabricated to validate the feasibility. Good agreement between the simulated and measured results is achieved. Moreover, the measured realized gains are over 11 dBi with a gain variation from the boresight direction to the tilted direction <0.2 dBi.