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Based on the principle of dynamic programming model, this paper studies the market transaction problem and establishes a transaction model to help decision-making. First, on the basis of the historical price data of gold and bitcoin, the data is processed by the wavelet transform method to ensure the accuracy of the model. Second, a time-series forecasting model and a back-propagation neural network are employed to predict the future prices of gold and bitcoin. And use a dynamic programming model to recursively determine the specific investment ratio of each asset in each transaction to achieve the best return. Finally, the effect of the model is verified by the evaluation index and transaction cost sensitivity test. The results show that transaction costs affect both strategy and outcomes. As transaction costs increase, both transaction frequency and total assets show a downward trend.

Mass independent fractionation (MIF) of even mercury (Hg) isotopes has long been observed in atmospheric related samples and is confirmed to be generated in the atmosphere, but its exact mechanism is covered up by the Hg sources and atmospheric transformations and stays unclear. Here, we present the first Hg isotope compositions of particulate bound mercury (PBM) in the Northwest Pacific and observe highly positive Δ200Hg values (up to 0.42 ‰). The MIF signatures are mainly controlled by photoreduction, gaseous elemental mercury (GEM) oxidation, and even-MIF dominated oxidation processes. Mercury in a small part of samples influenced by anthropogenic emissions is recognized by Hg concentrations and Δ199Hg signatures. The correlation between Δ200Hg and light conditions confirms that even-MIF is linked to photochemical reactions. The correlation between Δ200Hg and altitudes suggests that a max even-MIF signatures existed in the troposphere. We use Δ199Hg/Δ200Hg ratios and ternary isotopic mixing model to estimate the contributions of photoreduction, GEM oxidation and even-MIF dominated oxidation. Our results demonstrate that atmospheric transformations are far more important than Hg sources in shifting Hg isotope compositions of PBM samples, especially in the marine boundary layer of the open ocean, which is characterized by less anthropogenic influences and has implications for our understanding of the mechanism of even-MIF and subsequently Hg behaviors in the atmosphere.

A simple resorcinol method to determine nitrate (NO

Long non-coding RNAs are associated with cancer progression. Long intergenic non-protein coding RNA (linc)-regulator of reprogramming (ROR) enhances tumor development in hepatocellular carcinoma (HCC). However, the effect of chemoresistance and its underlying mechanisms in HCC are not completely understood. The present study aimed to identify the effect of ROR on sensitivity to doxorubicin (DOX) in HCC cells. In the present study, Cell Counting Kit-8 and EdU assays were performed to assess cell viability and proliferation, respectively. In addition, E-cadherin and vimentin protein expression levels were assessed via western blotting and immunofluorescence. The results of the present study demonstrated that HCC cells with high linc-ROR expression levels were more resistant to DOX, and linc-ROR knockdown increased HCC cell DOX sensitivity compared with the control group. The results indicated that compared with the NC siRNA group, linc-ROR knockdown notably suppressed epithelial-mesenchymal transition by downregulating twist family bHLH transcription factor 1 (TWIST1) expression. TWIST1 knockdown displayed a similar effect on HCC cell DOX sensitivity to linc-ROR knockdown. Moreover, linc-ROR knockdown-induced HCC cell DOX sensitivity was inhibited by TWIST1 overexpression. The present study provided evidence that linc-ROR promoted HCC resistance to DOX by inducing EMT via interacting with TWIST1. Therefore, linc-ROR might serve as a therapeutic target for reducing DOX resistance in HCC.

Pharmaceuticals and personal care products (PPCPs) in the sea area surrounding a densely populated tourist city in southeastern China were investigated. In total, 32 PPCP pollutants classified into 23 categories were detected. Different spatial distribution patterns of PPCPs indicated possible contamination from runoff and multiple local sources. The labile-to-conservative ratios of PPCPs showed the influence of untreated domestic sewage. In addition, increased concentrations of ciprofloxacin, enrofloxacin, and erythromycin around aquaculture farms imply that aquaculture cannot be neglected as a source. The concentrations of oxytetracycline, ranitidine, ciprofloxacin, miconazole, and sulfamethizole were higher in the wet season than those in the dry season, and the difference in pharmaceutical consumption was suspected to be the main driving factor of this seasonal variation. The risk quotients calculated with the maximum concentrations of miconazole, triclosan, dehydronifedipine, and triclocarban exceeded 0.1, indicating potential moderate or high risks. Antibacterial agents in daily chemicals and azole broad-spectrum antifungals were associated with the highest risks in this study; this might be another significant pollution characteristic in the sea area around this subtropical tourist city. Supplementary Information The online version contains supplementary material available at 10.1007/s11356-020-12335-1.

The safety and feasibility of laparoscopic versus open liver resection (LLR vs. OLR) associated lymphadenectomy for intrahepatic cholangiocarcinoma (ICC) are still controversial. The aim of the present study was to compare short and long-term outcomes. We reviewed data on 43 consecutive patients who underwent curative liver resection with associated lymphadenectomy for ICC. The short-term outcomes including postoperative morbidity and mortality, and the long-term outcomes including overall survival (OS) and recurrence-free survival (RFS) were compared. The median survival, 1- and 3-year OS in LLR and OLR groups were 22.5 months, 76.9% and 47.1%, and 12.1 months, 43.1% and 20.0%, respectively. The median survival, 1- and 3-year RFS in LLR and OLR groups were 10.3 months, 27.8% and 0%, and 8.1 months, 24.0% and 4.0%, respectively. The results showed that LLR obviously reduced intraoperative blood loss (median, 375 vs. 500ml, p = 0.016) and postoperative hospital stay (median, 6 vs. 9 days, p = 0.016). Moreover, there was no significant difference in short-term outcomes including postoperative morbidity (including wound infection, bile leakage, liver failure and pneumonia) and mortality within 30 days, and long-term outcomes including OS and RFS between LLR and OLR. (all p > 0.05). Multivariate analysis showed that CA19-9 level, TNM stage, and tumor differentiation were independent risk factors for OS and RFS. LLR for ICC is safety and feasibility compared with OLR. The advantage of LLR was to reduce intraoperative blood loss and postoperative hospital stay.

Resistance to chemotherapy drugs remains a significant problem for the treatment of many types of cancer. Fascin‑1 (FSCN‑1) is an actin-bundling protein involved in the invasion and metastasis of a variety of tumors. However, its involvement in drug resistance in hepatocellular carcinoma (HCC) remains unclear. The present study aimed to investigate the function of FSCN‑1 in HCC resistance to doxorubicin (DOX). FSCN‑1 expression was increased in DOX-resistant HCC cell lines (SNU449 and SNU387) compared with DOX-sensitive cell lines (Huh7 and Hep3B). The resistance of HCC cells to DOX was decreased following FSCN‑1 knockdown with small interfering RNA. FSCN‑1 knockdown also significantly altered the expression of key markers of epithelial-mesenchymal transition (EMT). Notably, vimentin expression was reduced and epithelial‑cadherin expression was increased. Furthermore, when EMT was suppressed through knockdown of Twist, an essential pathway of DOX-induced EMT, the viability of HCC cells following treatment with DOX was not affected by FSCN‑1 expression. Furthermore, FSCN‑1 knockdown eliminated hypoxia-induced doxorubicin resistance and EMT. The results of the present study indicated that FSCN‑1 expression increased DOX resistance in HCC cells via the promotion of EMT, and this phenomenon was maintained in a hypoxic environment. FSCN‑1 potentially represents a novel target to overcome resistance to DOX in HCC.

Isotope signatures of mercury (Hg) were determined for Hg fractions in seawater, sediments, porewaters, core sediments and fish from the Yundang Lagoon, Xiamen, China. Sequential extraction was used to extract Hg fractions in sediments and the purge-trap method was used to preconcentrate Hg in seawater. A large variation in mass dependent fractionation (δ202Hg: −2.50‰ to −0.36‰) was observed in the lagoon. Seawater and fish samples showed positive mass-independent fractionation (Δ199Hg: −0.06‰–0.45‰), while most of sediment and porewater samples displayed insignificant mass-independent fractionation (Δ199Hg: −0.10‰–0.07‰). Ancillary parameters (total organic carbon, sulfide, pH, Eh, water content and grain size) were also measured in the sediments to investigate correlations with Hg isotopes. Three sources (domestic sewage, sediments and atmospheric deposition) were identified as the main sources of Hg in the lagoon seawater. Photochemical reaction was the main process causing isotope fractionation in seawater. Through Hg partitioning and deposition, light isotopes were enriched from dissolved Hg to particulate Hg, then to sediments, and then to porewaters. Finally, Hg isotope signatures were used to identify the Hg sources and fractionation processes in core sediments from different depths. Our results demonstrate that Hg isotopes are powerful tools for tracing Hg sources and arriving at a better understanding of Hg biogeochemical cycling in the lagoon after long-term interventions.

Microplastic pollution is widespread across most ocean basins around the world. Microplastics (MPs) are small plastic particles that have a significant impact on the marine environment. Various research on plastic pollution have been conducted in several regions. However, currently, there is limited data on the distribution and concentration of MPs in the mid-west Pacific Ocean. Therefore, this study we investigated the abundance, distribution, characteristics, and compositions of MPs in this region. Sea surface water samples collected from 18 stations showed a microplastic concentration range of 6028–95,335 pieces/km2 and a mean concentration of 34,039 ± 25,101 pieces/km2. Highest microplastic concentrations were observed in the seamount region of western Pacific. We observed a significant positive correlation between microplastic abundance and latitude across the study region. It was observed that microplastic concentrations decreased with increasing offshore distance at sites located on a 154° W transect. Fibres/filaments were the dominant microparticles observed in this study (57.4%), followed by fragments (18.3%). The dominant particle size range was 1–2.5 mm (35.1%), followed by 0.5–1 mm (28.5%), and the dominant particle colour was white (33.8%), followed by transparent (31.0%) and green (24.6%). The most common polymer identified by μ-Raman was polypropylene (39.1%), followed by polymethyl methacrylate (16.2%), polyethylene (14.1%) and polyethylene terephthalate (14.2%). The possible sources and pathways of microplastics in the study area were proposed based on the morphological and compositional characteristics of particles, their spatial distribution patterns, and shipboard current profiling (ADCP). Our study contributes to the further understanding of MPs in remote ocean areas.

China is the largest plastic consumer in the world. Despite its plastic waste import ban in 2017, this populous economy inevitably generates a large amount of waste, including plastic waste, a considerable part of which has become marine litter. Data from the 2018 National Coastal Cleanup and Monitoring Project, the largest beach litter monitoring activities using the citizen science approach in China, have been retrieved and analyzed to understand spatial patterns, composition, and original usage of marine litter. Within this project, 24 beaches were surveyed every two months. As a result, the mean density was 3.85 ± 5.39 items m−2, much higher than that reported by previous studies in China. There were great differences in the spatial distribution of litter. The highest densities appeared in the runoff-affected area of the Yangtze River, which was another difference from previous studies. Low-density, easy-to-transport foamed plastics were the major contributor to marine litter in these areas. Along China's coast, approximately 90% of litter was from land-based sources, and over half of that originated from domestic sources. Including foamed plastic products, plastic litter with low recycling value dominated. Both natural and human factors influencing the spatiotemporal distribution and composition of litter are discussed. Socioeconomic factors, such as the lifestyle and consumption levels of citizens and local waste management systems, are possible explanations for the low-value characteristic of marine litter. The deviation between previous data and citizen science data in this study may be caused by many factors. Based on the discussion on these factors, some suggestions for citizen science research in China are also put forward.

People are increasingly aware of ubiquitous microplastic (MP) pollution in the world's ocean due to its far-reaching harmful impacts on marine ecosystem and potential hazards to human health, yet surprisingly comparatively limited studies about the abundance, source, transport, and fate of MPs in the Northwestern Pacific Ocean are available. We conducted the field survey of MPs pollution at the surface of the Northwestern Pacific Ocean between August 25 and September 26, 2017. MPs were collected from 18 sampling stations in the Northwestern Pacific Ocean using a manta trawl net with a mesh size of ∼330 μm and a rectangular net opening of 0.45 × 1 m. The abundance, shape, color, size, chemical composition, and surface morphology were characterized using light microscopy, μ-Raman spectroscopy, and scanning electron microscopy (SEM). The results show surface MPs at concentrations ranging over two orders of magnitude (6.4 × 102 to 4.2 × 104 particles km−2) and a mean abundance of 1.0 × 104 particles km−2. The most concentrated MPs were found at XTJ3-9, which may be associated with the convergence of surface currents collectively affected by the Kuroshio and its extension, adjacent eddies, and flow regimes. Polyethylene accounts for 57.8% of enumerated MPs, followed by polypropylene (36.0%) and nylon (3.4%). Pellets, sheets, lines, and films are major forms which may be linked to the breakdown of larger particles, aging processes, and movement over long distances by prevailing currents. Four possible MPs migration pathways were proposed based on the source-specific distribution, chemical fingerprints, size distribution patterns, and the observed physical oceanographic parameters.

We investigate the discrete nonlinear Schrodinger equations with indefinite sign subquadratic potentials. Making use of the critical point theory, we obtain a new result concerning the existence of a standing wave solution.

By using the critical point method, some new criteria are obtained for the existence and multiplicity of homoclinic solutions to a 2nth-order nonlinear difference equation. The proof is based on the Mountain Pass Lemma in combination with periodic approximations. Our results extend and improve some known ones.

In this paper, we obtain a new sufficient condition on the existence of breathers for the discrete nonlinear Schrodinger equations by using critical point theory in combination with periodic approximations. The classical Ambrosetti–Rabinowitz superlinear condition is improved.

High-resolution satellite observations of sea surface temperature (SST) were used to derive the daily SST fronts and monthly frontal probability (FP) in the South China Sea (SCS). A gradient-based frontal detection method was applied to increase the accuracy for frontal identification. The current study offered a comprehensive description for the variability of SST front and the associated dynamics in the SCS. Large variability was found along the coast of China and Vietnam, northwest of Luzon Island, and the corresponding seasonal cycle captured highest (lowest) values in winter (fall). The wind pattern was found highly influential for frontogenesis. The northeast monsoon in winter drove onshore Ekman transport near the coast of China, which induced convergence between coastal cold water and onshore warm water. The southwest monsoon during summer induced offshore transport, which brought upwelling near the coast of southeast Vietnam and east of Hainan Island. There were fronts generated between cold coastal water and offshore warm water during both monsoon patterns for impacted regions. The integrated effect from intrusion of the Kuroshio Current, wind stress curl and eddy activity were found favorable for generating fronts near Luzon Island. The dynamical relationship was more prominent at anomalous field that higher FP was associated with larger wind stress. And the interannual variability of fronts in the basin was clearly impacted by El Nino related large-scale atmospheric signals.

As a measure of the sustainability of a country, a state’s fragility is attributed to numerous elements. Meanwhile, climate change is a potential global threat in the 21st century, which may further aggravate the fragility of countries. Concerning this issue, we propose an index system, the Fragile States Metric System (FSMS) to measure state fragility, which includes five dimensions: climate change, cohesion, economy, politics and society. Our FSMS consists of the Climate Change Metric System (CCMS) and Modified Conflict Assessment System (M-CAS). While establishing the model, we introduce a new hybrid evaluation method, Gray Relational Analysis (GRA)-Entropy method and variable weight function model, to calculate the weights. As the result, from 2007 to 2017, European countries, in particular Finland, Norway, Switzerland, Sweden and Denmark, remained the top 5 most stable countries. Robustness analysis proves that FSMS is a relatively stable model. In addition, in the application of FSMS, we introduce the economic theory, Pareto Optimum, to measure intervention costs while mitigating state fragility.

In the fourth Chinese National Arctic Research Expedition (from July to September, 2010), 14 surface sediment samples were collected from the Bering Sea, Chukchi Sea, and Canadian Basin to examine the spatial distributions, potential sources, as well as ecological and health risk assessment of polycyclic aromatic hydrocarbons (PAHs). The ∑PAH (refers to the sum of 16 priority PAHs) concentration range from 27.66 ng/g to 167.48 ng/g (dry weight, d.w.). Additionally, the concentrations of ∑PAH were highest in the margin edges of the Canadian Basin, which may originate from coal combustion with an accumulation of Canadian point sources and river runoff due to the surface ocean currents. The lowest levels occurred in the northern of Canadian Basin, and the levels of ∑PAH in the Chukchi Sea were slightly higher than those in the Being Sea. Three isomer ratios of PAHs (Phenanthrene/Anthracene, BaA/(BaA+Chy), and LMW/HMW) were used to investigate the potential sources of PAHs, which showed the main source of combustion combined with weaker petroleum contribution. Compared with four sediment quality guidelines, the concentrations of PAH are much lower, indicating a low potential ecological risk. All TEQPAH also showed a low risk to human health. Our study revealed the important role of the ocean current on the redistribution of PAHs in the Arctic.

Prevalence of microplastics (MPs) throughout the world's oceans has raised growing concerns due to its detrimental effects on the environment and living organisms. Most recent studies of MPs, however, have focused on the estuaries and coastal regions. There is a lack of study of MPs pollution in the open ocean. In the present study, we conducted field observations to investigate the abundance, spatial distribution, and characteristics (composite, size, color, shape and surface morphology) of MPs at the surface of the Northwestern Pacific Ocean. Samples of MPs were collected at 18 field stations in the Northwestern Pacific Ocean using a surface manta trawl with a mesh size of ~330 μm and width of 1 m from August 25 to September 26, 2017. The MPs were characterized using light microscopy, Micro-Raman spectroscopy, and scanning electron microscopy (SEM). Our field survey results indicate the ubiquity of MPs at all stations with an abundance from 6.4 × 102 items km−2 to 4.2 × 104 items km−2 and an average abundance of 1.0 × 104 items km−2. The Micro-Raman spectroscopic analysis of the MPs samples collected during our field survey indicates that the dominant MPs is polyethylene (57.8%), followed by polypropylene (36.0%) and nylon (3.4%). The individual chemical compositions of MPs from the stations within the latitude range 123–146°E are comparable with each other, with PE being the dominating composition. Similar chemical fingerprints were observed at these field stations, suggesting that the MPs originated from similar sources. In contrast, the major MPs at the field stations adjacent to Japan is polypropylene, which may originate from the nearby land along the coast of Japan. Physical oceanography parameters were also collected at these stations. The spatial distribution of MPs is largely attributed to the combined effects of flow pattern, adjacent ocean circulation eddies, the Kuroshio and Kuroshio Extension system.

In this paper, we investigate the solutions of boundary value problems for second-order p-Laplacian difference equations. By using the critical point theory, the existence and multiple results are obtained.

By using the critical point theory, the existence of a nontrivial homoclinic orbit which decays exponentially at infinity for difference equations containing both advance and retardation is obtained. The proof is based on the Mountain Pass Lemma in combination with periodic approximations. Our results obtained successfully extend and complement the results in the literature.

In this paper, a class of fourth-order nonlinear difference equations are considered. By making use of the critical point method, we establish various sets of sufficient conditions for the nonexistence and existence of solutions for Neumann boundary value problems and give some new results. Our results successfully complement the existing ones.

Using the critical point theory, the existence of periodic solutions for a 2 $$n$$ th-order nonlinear difference equation containing both advance and retardation involving $$p$$ -Laplacian is obtained. The main approaches used in our paper are variational techniques and the Saddle Point Theorem. The problem is to solve the existence of periodic solutions for a 2 $$n$$ th-order $$p$$ -Laplacian difference equation. The obtained results successfully generalize and complement the existing ones.

In this paper, a fourth-order nonlinear difference equation is considered. By using the critical point theory, we establish various sets of sufficient conditions of the nonexistence and existence of solutions for mixed boundary value problem and give some new results. Results obtained generalize and complement the existing ones.

Chemotherapy drugs themselves may act as stressors to induce adaptive responses to promote the chemoresistance of cancer cells. Our previous research showed that sirtuin 1 (SIRT1) was overexpressed in pancreatic cancer patients and deregulation of SIRT1 with RNAi could enhance chemosensitivity. Thus, we hypothesized that SIRT1 might facilitate chemoresistance in pancreatic cancer cells through regulating the adaptive response to chemotherapy-induced stress. In the present study, SIRT1 in PANC-1, BXPC-3, and ASPC-1 cells was upregulated after treatment with gemcitabine. Moreover, the decrease in SIRT1 activity with special inhibitor EX527 had a synergic effect on chemotherapy with gemcitabine in PANC-1 and ASPC-1 cell lines, which significantly promoted apoptosis, senescence, and G0 /G1 cycle arrest. Western blot results also showed that SIRT1, acetylated-p53, FOXO3a, and p21 were upregulated after combined treatment, whereas no obvious change was evident in total p53 protein. To further confirm the role of SIRT1 in clinical chemotherapy, SIRT1 was detected in eight pancreatic cancer tissues acquired by endoscopy ultrasonography guided fine needle aspiration biopsy before and after chemotherapy. Compared to before chemotherapy, SIRT1 was significantly increased after treatment with gemcitabine in six cases. Thus, our results indicated a special role for SIRT1 in the regulation of adaptive response to chemotherapy-induced stress, which is involved in chemoresistance. Moreover, it indicates that blocking SIRT1 activity with targeting drugs might be a novel strategy to reverse the chemoresistance of pancreatic cancer.

Taking the heavy metal pollution in the urban surface soil as the object, this paper analyzes the degree of heavy metal pollution in different areas in the city and the main causes of pollution. Firstly, this paper uses Kriging interpolation method to increase the sample data together with Surfer software to draw the spatial distribution map of eight heavy metals, and then compares the single factor index method and the geological accumulation index-Nemero index method to make a comprehensive evaluation of the heavy metal pollution degree in different areas of the city. It is concluded that the pollution level in the area from slight to heavy is: mountain areas, park green areas, living areas, traffic areas, industrial areas. Then, the main comprehensive index of heavy metals is extracted by the principal component analysis, and the spatial distribution map of the main factors is drawn based on it. According to the spatial distribution map, the main cause of heavy metal pollution is the emission of automobile exhaust and industrial waste, which provides a reliable theoretical basis for the prevention and treatment of heavy metal pollution in the urban surface soil.

We focused on the economic and environmental impacts of regional widespread use of Electric Vehicles (EV). Massive introduction of battery and plug-in hybrid EV will affect the regional energy consumption significantly and therefore, influence environment situations. In this study, we adopted performance price ratio to evaluate cost effectiveness of conventional vehicles and electric vehicles and introduced Grey Relational Analysis method to evaluate environmental changes. Sensitivity analyses indicate that electricity and gasoline price fluctuation will not significantly change cost effectiveness of conventional vehicles and that large scale introduction of EV requires improvement of EV's driving range and adequate charging stations. Electricity generation system also needs to be adjusted to reduce incremental SO 2 pollution.

By using the critical point theory, some new criteria are obtained for the existence and multiplicity of periodic and subharmonic solutions to a 2 n th-order nonlinear difference equation containing both advance and retardation involving p -Laplacian. The proof is based on the Linking Theorem in combination with variational technique. Our results generalize and improve the results in the literature.

In the flywheel charging-control system, there exists the flywheel motor's nonlinearity, variable elements etc, which leads to the problem of parameter tuning of PID controller of its charging-control system's revolving speed loop. In this study, I will introduce an optimizing way based on modified genetic algorithm for the flywheel charging-control system PID controller, which by means of simulation and performance index quantization to observe its optimizing performance and convergence characteristic, so that we can check the feasibility and effectiveness in the flywheel charging-control system. It turns out that tuning PID controller parameters based on modified genetic algorithm has a better rapidity and stability, which proves the feasibility of the modified genetic algorithm.

Given the rise in popularity of river rafting, we need to schedule an optimal mix of trips of varying duration and propulsion to meet the needs of travelers and improve the company's interests. To provide a wilderness experience for travelers, we should try to reduce the contacts during the traveling. We firstly analyze the traveling process. And one contact (on-river) is counted. We apply step-to-step method to this study. We firstly study this relationship when there is only one kind of travel days. Then we add another kind of travel days to draw the universal rule and finally we derive the relationship when there are many kinds of trips. In order to combine the contacts and company's interests, we define two satisfaction degree functions by using fuzzy logic. We define a satisfaction degree function to describe the contacts. Then we define another function to describe the company's interests. Lastly, we define a composite index to combine the two functions by giving them different weight. We base this model on maximizing this composite index and obtain the optimal schedule. When determining the carrying capacity of the river, we take contacts, company's interests and river's resources into account. In the same way, we define a satisfaction degree function for river's resources. We finally define a composite index to combine the three factors by giving them different weights. We base this model on maximizing this composite index and derive the river's carrying capacity.

By using the critical point theory, the existence of periodic solutions for 2$n$th-order nonlinear $p$-Laplacian difference equations is obtained. The main approaches used in our paper are variational techniques and the Saddle Point theorem. The problem is to solve the existence of periodic solutions for 2$n$th-order $p$-Laplacian difference equations. The results obtained successfully generalize and complement the existing ones.

By using the critical point theory, the existence of periodic solutions for a $2n$th-order nonlinear difference equation is obtained. The main approaches used in our paper are variational techniques and the Saddle Point Theorem. The problem is to solve the existence of periodic solutions for a $2n$th-order nonlinear difference equation. Results obtained successfully complement the existing one.

By using the critical point theory, some new criteria are obtained for the existence and multiplicity of periodic solutions to a class of nonlinear difference equations. The proof is based on the Linking Theorem in combination with variational technique. Our results successfully generalize and improve some existing results in the literature.

Amac: Bu cal›flmada, primer hepatik noroendokrin tumorlerde klinik karakteristikleri, patolojik ozellikleri, tedavi yaklafl›mlar›n› ve prognostik faktorleri incelemeyi amaclad›k. Gerec ve Yontem: Cal›flmada hastanemizde Ocak 2003 - Ocak 2010 tarihleri ara- s›nda tedavi edilen 9 primer hepatik noroendokrin tumor hastas›n›n klinik karakteristikleri, patolojik ozellikleri, tedavileri ve prog- nostik faktorleri incelendi. Bulgular: Klinik bulgular deiflkendi ve ozgul deildi. En s›k gorulen belirti distansiyon veya sa¤ ust kadran ar›s›yd›. Radyolojik bulgular ozgul deildi ve primer hepatik noroendokrin tumoru hepatoselluler kanserden ay›r edemi- yordu. Primer hepatik noroendokrin tumor tan›s› immunohistokimyasal olarak ve ekstrahepatik hastal›¤›n olmamas› ile konuldu. Cal›flmam›zda operasyon oncesi donemde veya takipte ultrasonografi, tomografi, manyetik rezonans veya pozitron emisyon tomog- rafi ile ektrahepatik tumor tesipt edilmedi. ‹mmunohistokimyasal olarak sinaptofizin, kromagranin A ve CD56 boyanmalar› dik- kate al›narak primer hepatik noroendokrin tumor tan›s› konuldu. Primer hepatik noroendokrin tumorun prognozu en cok rezekta- biltesi ile iliflkili bulundu. En s›k lezyonun tam olarak c›kart›lmas› onerildi. Ayr›ca kemoterapi, transarteriyel kemoembolizasyon ve radyofrekans ablasyon gibi cok yonlu tedaviler pre-operatif ve post-operatif donemde kullan›larak sakal›m artt›r›lmal›d›r. Sonuc: Primer hepatik noroendokrin tumor nadir gorulen bir antitedir ve tan›s› zordur. Operasyon oncesinde ince ine biyopsisi tavsiye edilmektedir ve kemoterapi, transarteriyel kemoembolizasyon veya radyoterapinin cerrahi ile kombine edilmesi en etkin te- davi yontemidir. Background/aims: We aimed to analyze the clinical characteristics, pathologic features, treatment approaches, and prognostic fac- tors of primary hepatic neuroendocrine tumor. Materials and Methods: We retrospectively analyzed the clinical characteristics, pathologic features, treatment approaches, and prognostic factors of 9 patients with primary hepatic neuroendocrine tumor treated in our hospital from January 2003 to January 2010. Results: The clinical manifestations were nonspecific and variable. The most common clinical manifestation was distention or right upper quadrant pain. Radiological findings are not specific and cannot dis- tinguish primary hepatic neuroendocrine tumor from hepatocellular carcinoma. Diagnosis of primary hepatic neuroendocrine tu- mor was confirmed immunohistochemically and by the absence of extrahepatic primary sites. No extrahepatic primary lesions we- re found by ultrasonography, computed tomography, magnetic resonance imaging or positron emission tomography scan either pre- operatively or during the follow-up period in our research. Immunohistologically, synaptophysin, chromogranin A and CD56 sho- uld be used as markers to precisely diagnose primary hepatic neuroendocrine tumor. The outcome of primary hepatic neuroendoc- rine tumor is mostly related to its resectability. Total resection of the neoplasm is most commonly proposed. A multimodality of tre- atments, including chemotherapy, transarterial chemoembolization and radiofrequency ablation, should be used pre- or postopera- tively to improve the survival. Conclusions: Primary hepatic neuroendocrine tumor is a rare entity, and its diagnosis is difficult. Preoperative fine needle biopsy is strongly recommended, and primary surgery integrated with chemotherapy, transarterial chemo- embolization or radiotherapy is considered to be an effective modality for primary hepatic neuroendocrine tumor.

In this paper, some sufficient conditions for the existence and multiplicity of periodic and subharmonic solutions to second order p-Laplacian difference equations are obtained by using the critical point theory. The proof is based on the Linking theorem in combination with variational technique.

This paper takes wine quality evaluation as the research object, establishes the analysis and evaluation model of wine quality, and explores the influence of physical with chemical indicators of wine grapes and wine on the wine quality. Firstly, the Mann-Whitney U test is used to analyze the wine evaluation results of the two wine tasters, and it is found that the significant difference between the two is small. Then this paper uses the Cronbach Alpha coefficient method to analyze the credibility of the two groups of data. It is found that the credibility of the first group of wine scores is significantly greater than that of the second group and the white wine scores are more reliable than the red wine. Therefore, the first set of data and white wine can be applied for follow-up studies. Next, the principal component analysis is used to extract the main indicators and calculate the factor coefficients as the Ward method in cluster analysis is used to classify the wine into four grades according to the quality score of the wine. Then, based on the extracted principal components that is physical with chemical indicators, this paper does the multiple linear regression analysis of wine quality, and takes the influence of aromatic substances on the aroma of wine in physical with chemical indicators as an example. Regression analysis shows that there is a positive correlation linear relationship between the scores of the aroma of wine and C 2 H 6 O, C 6 H 12 O 2 , C 3 H 8 O, C 11 H 24 , C 7 H 12 O 2 , C 5 H 10 O 2 and C 10 H 16 . It can be judged that the aromatic substances in the wine such as C 2 H 6 O have a regular influence on the odor of the wine, and it is inferred that other physical and chemical properties have a similar regular relationship with the wine quality. This provides an effective reference for the analysis and evaluation of wine quality by using physical with chemical indicators such as aromatic substances in wine in the future.

When reconciling balance between economic development and ecosystem health, a sustainable future is imperative but hard to distinguish. We focus on setting up an index assessment system for evaluating sustainable development. Using the data from 1995 to 2016, we utilize the AHP serving for data selection. Besides, the Gray Relational Analysis and the Entropy Method are employed to identify the index value. Two methods' calculation results lead to different weighting structures so the combination is adopted. We draw on six sample countries to inspect the impact of national behavior on sustainability. The result shows that the countries that are sustainable are the minority. The index of a country varies from year to year.

In order to have a better study of pricing of crowdsourcing APP tasks, mission data was collected about an already completed project, including the location, pricing and fulfillment of each mission. Get the law of the task pricing of the completed projects by analyzing the location distribution of the task points and the members, and then analyze the reason of the task failure. Besides, combine the information data of the members to improve the original pricing model based on the K-means clustering. Focus on the task package pricing, design a better task pricing model to improve the success rate of the task.

By using the critical point method, some new criteria are obtained for the existence and multiplicity of periodic and subharmonic solutions to a 2nth-order nonlinear dierence equation. The proof is based on the Linking Theorem in combination with variational technique. Our results generalize and improve some known ones. 2000 AMS Classification: 39A11.

Hazard avoidance is one of the key stages in the satellite's soft landing process, during which the selection of the landing site would have a huge influence on the satellite safe landing. In this paper, a new design method is presented for determining the landing site selection using Particle Swarm Optimization based on the Moon’s grounds image taken by moon satellite. Applying this method, the problem of hazard avoidance can be converted into the optimization of the value of “obstacle function” after processing the image employing the median filter algorithm. In order to discuss and to compare the efficiency of the different optimization methods, three algorithms including Particle Swarm Optimization, Genetic Algorithm and Global Search Algorithm are tested to solve this problem. The results show that Particle Swarm Optimization has the more satisfactory optimization results and the quickest optimization speed in the landing site selection. The detailed comparisons are introduced in the body paragraph.

This paper aims to establish a quantitative trading strategy of commodity futures based on market money flows. Firstly, we use Accumulation/Distribution index to respectively construct the CMF index which represents the ratio of total capital flows to total volume, and the CHO index which represents the exponential moving average of the cumulative capital flows. In view of the different flows of money between buyers and sellers, the establishment of the transaction net volume index VTL is used to describe respectively the flow of money between buyers and sellers. On this basis, the HMM model is introduced, and the above three kinds of indexes are combined to choose the time, at which we execute the stop-loss operation and risk control. Finally, all performance index values of the strategy are as follows: the rate of initial capital return is 193.77%, the annual rate of return is 99.86%, the maximum retracement rate is 15.73%, the Sharpe rate is 2.05 and the price earnings ratio is 4.01.

This paper is concerned with a class of fourth-order nonlinear difference equations. By making use of the critical point theory, we establish various sets of sufficient conditions for the nonex- istence and existence of solutions for mixed boundary value problem and give some new results. Results obtained generalize and comple- ment the existing ones.