Forecasting S&P 500 Stock Index Using Statistical Learning Models

Forecasting the movement of stock market is a long-time attractive topic. This paper implements different statistical learning models to predict the movement of S&P 500 index. The S&P 500 index is influenced by other important financial indexes across the world such as commodity price and financial technical indicators. This paper systematically investigated four supervised learning models, including Logistic Regression, Gaussian Discriminant Analysis (GDA), Naive Bayes and Support Vector Machine (SVM) in the forecast of S&P 500 index. After several experiments of optimization in features and models, especially the SVM kernel selection and feature selection for different models, this paper concludes that a SVM model with a Radial Basis Function (RBF) kernel can achieve an accuracy rate of 62.51% for the future market trend of the S&P 500 index.

Quantifying the Microeconomic and Macroeconomic Impact of the Recent Crude Oil Price Fluctuations

This study analyzed the potential impact of the increased oil volatility on the industries and the global economy. Specifically, it separated the oil price fluctuations into positive and negative components, and modeled the return of industry portfolios with them. Next, the sensitivity of the airline industry to oil price was investigated to gauge the effectiveness of their hedging strategies, with the hope that the methodology can be extended to other industries. In addition, this paper explored the macroeconomic impact of oil price movements by examining the benchmarks such as GDP and CPI.

抑制植物减数分裂重组的分子机理

减数分裂重组不仅保证了真核生物有性生殖过程中染色体数量的稳定,还通过父母亲本间遗传物质的互换在后代中产生遗传变异。因此,减数分裂重组是遗传多样性形成的重要途径,也是生物多样性和物种进化的主要动力。在绝大多数真核生物中,不管染色体数目的多少或基因组的大小,减数分裂重组的形成都受到严格的调控,但抑制减数分裂重组的分子机理目前仍不清楚。近年来,通过正向遗传学筛选鉴定出多个减数分裂重组抑制基因,揭示了抑制基因的功能和调控途径。本文基于拟南芥中减数分裂重组抑制基因的研究现状,综述了植物减数分裂重组抑制基因研究取得的突破性进展,并结合基因功能与其调控网络阐述了抑制植物减数分裂重组的分子机理。

Gap-free genome assembly and comparative analysis reveal the evolution and anthocyanin accumulation mechanism of Rhodomyrtus tomentosa

Rhodomyrtus tomentosa is an important f leshy-fruited tree and a well-known medicinal plant of the Myrtaceae family that is widely cultivated in tropical and subtropical areas of the world.However,studies on the evolution and genomic breeding of R.tomentosa were hindered by the lack of a reference genome.Here,we presented a chromosome-level gap-free T2T genome assembly of R.tomentosa using PacBio and ONT long read sequencing.We assembled the genome with size of 470.35 Mb and contig N50 of∼43.80 Mb with 11 pseudochromosomes.A total of 33382 genes and 239.31 Mb of repetitive sequences were annotated in this genome.Phylogenetic analysis elucidated the independent evolution of R.tomentosa starting from 14.37MYA and shared a recent WGD event with other Myrtaceae species.We identified four major compounds of anthocyanins and their synthetic pathways in R.tomentosa.Comparative genomic and gene expression analysis suggested the coloring and high anthocyanin accumulation in R.tomentosa tends to be determined by the activation of anthocyanin synthesis pathway.The positive selection and up-regulation of MYB transcription factors were the implicit factors in this process.The copy number increase of downstream anthocyanin transport-related OMT and GST gene were also detected in R.tomentosa.Expression analysis and pathway identification enriched the importance of starch degradation,response to stimuli,effect of hormones,and cell wall metabolism during the f leshy fruit development in Myrtaceae.Our genome assembly provided a foundation for investigating the origins and differentiation of Myrtaceae species and accelerated the genetic improvement of R.tomentosa.

A high-quality genome assembly of Morinda officinalis,a famous native southern herb in the Lingnan region of southern China

Morinda officinalis is a well-known medicinal and edible plant that is widely cultivated in the Lingnan region of southern China.Its dried roots(called bajitian in traditional Chinese medicine)are broadly used to treat various diseases,such as impotence and rheumatism.Here,we report a high-quality chromosome-scale genome assembly of M.officinalis using Nanopore single-molecule sequencing and Hi-C technology.The assembled genome size was 484.85Mb with a scaffold N50 of 40.97 Mb,and 90.77%of the assembled sequences were anchored on eleven pseudochromosomes.The genome includes 27,698 protein-coding genes,and most of the assemblies are repetitive sequences.Genome evolution analysis revealed that M.officinalis underwent core eudicotγgenome triplication events but no recent whole-genome duplication(WGD).Likewise,comparative genomic analysis showed no large-scale structural variation after species divergence between M.officinalis and Coffea canephora.Moreover,gene family analysis indicated that gene families associated with plant–pathogen interactions and sugar metabolism were significantly expanded in M.officinalis.Furthermore,we identified many candidate genes involved in the biosynthesis of major active components such as anthraquinones,iridoids and polysaccharides.In addition,we also found that the DHQS,GGPPS,TPS-Clin,TPS04,sacA,and UGDH gene families—which include the critical genes for active component biosynthesis—were expanded in M.officinalis.This study provides a valuable resource for understanding M.officinalis genome evolution and active component biosynthesis.This work will facilitate genetic improvement and molecular breeding of this commercially important plant.

Erythropoiesis-stimulating agents in the management of cancer patients with anemia: a meta-analysis

Background： Erythropoiesis-stimulating agents （ESAs） are widely used in the management of anemia in cancer patients. Despite their apparent effectiveness, recent studies have suggested that ESAs could result in serious adverse events and even higher mortality. The aim of the current study was to evaluate the benefits and risks of ESAs in the management of cancer patients with anemia using a recta-analysis. Methods： The initial literature search covered Medline, PubMed, Embase, and the Cochrane Center Register of Controlled Trials, and identified 1,569 articles. The final meta-analysis included eight randomized controlled trials （n=2,387） in cancer patients with 〈11 g/dL hemoglobin （Hb） at the baseline and target Hb （for stopping ESA treatment） at no more than 13 g/dL. The assessment measures included Hb response, blood transfusion rate and adverse events that included venous thromboemblism （VTE）, hypertension, and on-study mortality. The results are expressed as pooled odds ratio （OR）. Publication bias was assessed using funnel plot analysis. Results： ESAs significantly increased the Hb concentration [OR 7.85, 95% confidence interval （CI）： 5.85 to 10.53, P〈O.O01] and reduced the red blood cell （RBC） transfusion rate （OR 0.52, 95% CI： 0.42 to 0.65, P〈0.001）. ESAs did not increase the accumulated adverse events （OR 0.95, P=0.82）, or the on-study mortality （OR 1.09, P=0.47）. Conclusions： ESAs are not associated with increased frequency of severe adverse events in anemic cancer patients when the target Hb value is no more than 13 g/dL.

Identification of reference genes provides functional insights into meiotic recombination suppressors in Gerbera hybrida

Gerbera Hybrida is one of the important cut flowers across the world.The novel traits are the primarily market requirements and the breeding targets,mainly determined by the degree of genetic variation after hybridization.However,meiotic recombination is highly conserved in most eukaryotes which suppressed the crossover formation and limited the genetic diversity.Recently,several meiotic recombination suppressors have been identified and characterized in plants,whereas it remains elusive in G.hybrida.In order to characterize the expression patterns of these suppressors in G.hybrida,20 candidate reference genes were identified from the transcriptome datasets of G.hybrida,and their expression stabilities during plant development were evaluated by geNorm,NormFinder and BestKeeper.Although the most stable reference genes were variable in different softwares,comprehensive ranking revealed that PGK2 was the most stable reference gene and GAPDH was the most unstable one.The expression patterns of FANCM,FIGL1,RECQ4,RM1,and FLIP further validated that PGK2 was suitable for normalization of gene expression.Our study identified a reliable reference gene for gene expression during meiotic recombination,and provided functional insights into meiotic recombination suppressors in G.hybrida.

Comparative transcriptome and proteome analysis of lily clones inoculated with Fusarium oxysporum f. sp. lilii

Basal bulb rot is the major factor restricting the production of lily,caused by Fusarium oxysporum f.sp.lilii.To systematically analyze the transcriptomic and proteomic responses of lily clones to F.oxysporum,we constructed six RNA-seq libraries and four iTRAQ proteomic libraries using lily resistant and susceptible clones sampled at 0,24 and 48 h post-inoculation(hpi)with F.oxysporum respectively.137,715 unigenes were generated,of which 7,667 were differentially expressed.1,679 and 4,051 differentially expressed genes(DEGs)between resistant and susceptible clones were isolated from samples collected at 0 and 48 hpi.Four hundred and thirty three and 155 DEGs were identified in resistant clones sampled at 24 and 48 hpi separately while 550 and 799 DEGs were isolated in the susceptible clones sampled at 24 and 48 hpi respectively.The results of iTRAQ analysis revealed 7,482 proteins in resistant and susceptible clones.Data analysis of transcriptome and proteome indicated that 5,735 proteins corresponded to mRNAs.Three hundred and sixteen and 1,052 DEGs had corresponding DEPs.At 48 hpi,the resistant clones showed 155 DEGs and 108 corresponding DEPs,while the susceptible clones showed 799 DEGs and 316 corresponding DEPs.In general,these results enhance comprehension of the defense response of lily resistant clones to F.oxysporum infection and provide valuable sequence data for studying the resistance mechanism.

Effect of Different Pesticides on Lipase Production by Isaria fumosorosea

The influence of twelve different pesticides(six insecticides and six fungicides) on lipase production by Isaria fumosorosea was investigated under laboratory conditions. Imidacloprid caused higher reduction in enzyme activities at all three concentrations whereas very low reduction in enzyme activities was caused by azadrichtin and Indoxacarb when used at 10μg/ml. In case of fungicides, propiconazole and pyraclostrobin caused higher reduction in enzyme activities at all three concentrations whereas low reduction in enzyme activities was caused by chlorothalonil and mancozeb when used at 10 μg/ml. Different insecticides significantly affected the toxicity of I. fumosorosea lipase against second instar Dysmicoccus neobrevipesnymphs. I.fumosorosea lipase combined with azadrichtin was proved to be the most aggressive, and those from control were the least virulent with a mean ST50 value of 6.34 ± 0.41 d.

Current Fertilization Practice and Phosphorus Loading from Soils near Alpine Lakes of Yunnan Province, China

Phosphorus loss from fertilization is a significant source of pollution to freshwater lakes worldwide. Production of flowers, vegetables, staple food and vineyard in regions surrounding Dianchi, Erhai, Fuxian and Xingyun lakes in Yunnan Province is large-scale. Previous studies have shown that annual fertilizer application rates (AFARs) were excessive in these regions. Significant amount of arable land near lakes has been used to build recreational parks with plants that receive less fertilization to reduce P loading. To answer whether rAFARs were associated with specific crops, AFARs of specific land uses were investigated through interviews. To estimate P loading, NaHCO3-P and NaOH-P concentrations were measured in 753 soil samples of selected layers (0 - 5, 5 - 20, 20 - 40 cm) in regions surrounding these lakes. Soil texture, pH, and cation exchange capacity (CEC) were analyzed to characterize soils. P loading was high ranging from 999 to 2094 mg P/kg as measured by NaOH-P, and levels of NaHCO3-P from 18.6 to 92.2 mg P/kg. AFARs to flower (4745 kg/ha), and vegetable (2967 kg/ha) were higher than those applied to staple food (945 kg/ha), and plants in recreation parks (200 kg/ha). The highest NaHCO3-P and NaOH-P concentrations in selected layers were associated with production of flowers, vegetables, and grapes. Although all layers of soils that were used for recreation parks in regions near Dianchi lake contained lower NaHCO3-P, NaOH-P was almost as high as with soils cultivated with flowers probably reflecting historical additions or differences in soil type. Here we show for the first time in local regions that the production of flowers, grapes and vegetables was a critical source contributing to the buildup of both readily available (NaHCO3-P) and reversibly available P (NaOH-P). Build-up of recreational parks with plants that receive less fertilization would be a long-term remediation to reduce P loading of soils in regions near Dianchi lake.

Decoding the chromatin accessibility in Andrographis paniculata genome,a case study of genome-wide investigation of the cis-regulatory elements in medicinal plants

To the Editor:Medicinal plants have the ability to synthesize a large number of pharmaceutical metabolites,the production and regulation of which are influenced by both intrinsic signals(e.g.,the spatial and temporal stage)and extrinsic environmental conditions(e.g.,temperature,light availability,and water availability)^(1).According to the Encyclopedia of DNA Elements(ENCODE)project^(2),accessible chromatin regions(ACRs)served essential roles in maintaining the genome architecture and gene regulation in both mammals and plants.Nowadays,identifying ACRs within medicinal plant genomes remains a challenge,as genomic sequences have been determined for numerous species yet the characterization of such functional elements lags.In this study,we selected Andrographis paniculata(APA)^(3) as a model system to map ACRs genome-wide by the assay for transposase-accessible chromatin with sequencing(ATAC-seq)method.We aimed to uncover the genomic features of ACRs as well as their association with the expression of genes involved in secondary metabolite biosynthesis(e.g.,andrographolide)within medicinal plants(Supporting Information Fig.S1).

聚偏氟乙烯基复合材料的制备及介电性能

为有效改善聚合物基复合材料的介电性能,兼顾高介电常数和低填料量同时并存,采用以聚偏氟乙烯(PVDF)为基体树脂,钛酸钡(BT)和石墨烯(GNP)分别为介电填料和导电填料,在BT-GNP/PVDF复合体系内部构建微电容器结构。采用溶液法和热压法制备GNP/PVDF薄膜和BT-GNP/PVDF复合薄膜。结果表明,BT和GNP填料在BT-GNP/PVDF复合薄膜中能够均匀分散,在薄膜内能形成明显的微电容器结构。陶瓷填料BT的引入,使微电容器结构更有利于提高BT-GNP/PVDF复合薄膜的介电常数。BT含量大于50wt%的BT-GNP/PVDF复合薄膜介电常数均不低于GNP/PVDF薄膜。BT含量为50wt%的BT-GNP/PVDF复合薄膜的介电常数高于BT含量分别为35wt%、60wt%和70wt%的BT-GNP/PVDF复合薄膜,最大值约为43,相当于GNP含量为0.8wt%的GNP/PVDF薄膜的1.5倍;BT含量为50wt%的BT-GNP/PVDF复合薄膜损耗角正切均小于其他体系薄膜,最大不超过0.09,最小约为0.02。BT-GNP/PVDF复合薄膜的电导率变化趋势基本一致,没有明显差异。

Mini-review of application of IoT technology in monitoring agricultural products quality and safety

Internet of Things(IoT)technology has been identified as one of the emerging technologies in information technology(IT),which is widely used in all walks of life in the world.The key technologies of IoT technology,such as radio frequency identification(RFID),wireless sensor network(WSN),sensors and global positioning system(GPS),had been widely used in farmland and greenhouse management,environmental monitoring,cold chain monitoring and tracking,and traceability,etc.As advancements in science and technology,IoT technology has been widely applied in agricultural products quality and safety,which brought a number of potential benefits for detecting agricultural products easier and automatically,improving the efficiency and speed of operations,decreasing the labor cost,promoting the agricultural products quality and safety.This paper intended to introduce the concept of IoT technology,the key technologies used at present and review the recent applications of IoT technology in monitoring agricultural products quality and safety in the whole industry chain,such as production,processing,circulation,sales and traceability.Challenges and trends of agricultural products quality and safety in the future were also discussed.

Illuminating the Activated Brain: Emerging Activity-Dependent Tools to Capture and Control Functional Neural Circuits

Immediate-early genes(IEGs) have long been used to visualize neural activations induced by sensory and behavioral stimuli. Recent advances in imaging techniques have made it possible to use endogenous IEG signals to visualize and discriminate neural ensembles activated by multiple stimuli, and to map whole-brain-scale neural activation at single-neuron resolution. In addition, a collection of IEG-dependent molecular tools has been developed that can be used to complement the labeling of endogenous IEG genes and, especially, to manipulate activated neural ensembles in order to reveal the circuits and mechanisms underlying different behaviors. Here, we review these techniques and tools in terms of their utility in studying functional neural circuits. In addition, we provide an experimental strategy to measure the signal-to-noise ratio of IEG-dependent molecular tools, for evaluating their suitability for investigating relevant circuits and behaviors.

Chemical constituents from the the twigs and leaves of Caesalpinia enneaphylla

Fifteen compounds were isolated from the twigs and leaves of Caesalpiniaenneaphylla. Their structures were identified to be: (E)-3-(4-hydroxybenzylidene)- 5,7-dihydroxychroman-4-one (1), 8-methoxybonducellin (2), (E)-3-(3,4- dihydroxybenzylidene)-5,7-hydroxychroman-4-one (3), 2′,4′-dihydroxychalcone (4), oxyfadichalcone B (5), 7-hydroxyflavonone (6), pinocembrin (7), kaempferol (8), quercitrin (9), kaempferol 3-O-α-L-rhamnopyranoside (10), quercetin 3-O-α-D-arabinoside (11), trans-2,3-diacetoxy-1-[(benzoyloxy)methyl]-cyclohexa-4,6-diene (12), 3-hydroxybenzyl benzoate (13), 2-acetoxybenzyl benzoate (14), and glutinol (15). All the compounds were isolated from C. enneaphylla for the first time.

Improvement of nitrification efficiency by bioaugmentation in sequencing batch reactors at low temperature

Bioaugmentation is an effective method of treating municipal wastewater with high ammonia concentration in sequencing batch reactors （SBRs） at low temperature （10℃）. The cold-adapted ammonia- and nitrite- oxidizing bacteria were enriched and inoculated, respectively, in the bioaugmentation systems. In synthetic wastewater treatment systems, the average NH4＋-N removal efficiency in the bioaugmented system （85%） was much higher than that in the unbioaugmented system. The effluent NH4＋ -N concentration of the bioaugmented system was stably below 8 mg. L1 after 20 d operation. In municipal wastewater systems with bioaugmentation, the effluent NH4＋- -N concentration was below 8 mg·L^-1 after 15 d operation. The average NH4＋ -N removal efficiency in unbioaugmentation system （about 82%） was lower compared with that in the bioaugmentation system. By inoculating the cold-adapted nitrite-oxidizing bacteria （NOB） into the SBRs after 10 d operation, the nitrite concentration decreased rapidly, reducing the NO2 -N accumulation effectively at low temperature. The func- tional microorganisms were identified by PCR-DGGE, including uncultured Dechloromonas sp., uncultured Nitrospira sp., Clostridium sp. and uncultured Thauera sp. The results suggested that the cold-adapted microbial agent of ammonia-oxidizing bacteria （AOB） and NOB could accelerate the start-up and promote achieving the stable operation of the low-temperature SBRs for nitrification.

Mechanical stretching boosts expansion and regeneration of intestinal organoids through fueling stem cell self-renewal

Intestinal organoids,derived from intestinal stem cell self-organization,recapitulate the tissue structures and behav-iors of the intestinal epithelium,which hold great potential for the study of developmental biology,disease modeling,and regenerative medicine.The intestinal epithelium is exposed to dynamic mechanical forces which exert profound effects on gut development.However,the conventional intestinal organoid culture system neglects the key role of mechanical microenvironments but relies solely on biological factors.Here,we show that adding cyclic stretch to intestinal organoid cultures remarkably up-regulates the signature gene expression and proliferation of intestinal stem cells.Furthermore,mechanical stretching stimulates the expansion of SOX9+progenitors by activating the Wnt/β-Catenin signaling.These data demonstrate that the incorporation of mechanical stretch boosts the stemness of intestinal stem cells,thus benefiting organoid growth.Our findings have provided a way to optimize an organoid generation system through understanding cross-talk between biological and mechanical factors,paving the way for the application of mechanical forces in organoid-based models.

Overcoming Debye length limitations:Three-dimensional wrinkled graphene field-effect transistor for ultra-sensitive adenosine triphosphate detection

Adenosine triphosphate(ATP)is closely related to the pathogenesis of certain diseases,so the detection of trace ATP is of great significance to disease diagnosis and drug development.Graphene field-effect transistors(GFETs)have been proven to be a promising platform for the rapid and accurate detection of small molecules,while the Debye shielding limits the sensitive detection in real samples.Here,a three-dimensional wrinkled graphene field-effect transistor(3D WG-FET)biosensor for ultra-sensitive detection of ATP is demonstrated.The lowest detection limit of 3D WG-FET for analyzing ATP is down to 3.01 aM,which is much lower than the reported results.In addition,the 3D WG-FET biosensor shows a good linear electrical response to ATP concentrations in a broad range of detection from 10 aM to 10 pM.Meanwhile,we achieved ultra-sensitive(LOD:10 aM)and quantitative(range from 10 aM to 100 fM)measurements of ATP in human serum.The 3D WG-FET also exhibits high specificity.This work may provide a novel approach to improve the sensitivity for the detection of ATP in complex biological matrix,showing a broad application value for early clinical diagnosis and food health monitoring.