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Search Results: 1 - 10 of 35126 matches for " Yi Gu "
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On algebraic surfaces of general type with negative c2
Yi Gu
Mathematics , 2014,
Abstract: We prove that for any prime number $p\ge 3$, there exists a positive number $\kappa_p$ such that $\chi(\mathcal{O}_X)\ge \kappa_pc_1^2$ holds true for all algebraic surfaces $X$ of general type in characteristic $p$. In particular, $\chi(\mathcal{O}_X)>0$. This answers a question of N. Shepherd-Barron when $p\ge 3$.
On Pluri-canonical Systems of Arithmetic Surfaces
Yi Gu
Mathematics , 2014,
Abstract: Let $S$ be a Dedekind scheme with perfect residue fields at closed points, let $f: X\rightarrow S$ be a minimal regular arithmetic surface of fibre genus at least $2$ and let $f': X'\rightarrow S$ be the canonical model of $f$. It is well known that $\omega_{X'/S}$ is relatively ample. In this paper we prove that $\omega_{X'/S}^{\otimes n}$ is relative very ample for all $n\geq 3$.
Identifying species-specific subsequences in bacteria transcription terminators-A machine learning approach  [PDF]
Bao-Hua Gu, Yi Sun
Journal of Biomedical Science and Engineering (JBiSE) , 2009, DOI: 10.4236/jbise.2009.23031
Abstract: Transcription Terminators (TTs) play an impor-tant role in bacterial RNA transcription. Some bacteria are known to have Species-Specific Subsequences (SSS) in their TTs, which are be-lieved containing useful clues to bacterial evolu-tion. The SSS can be identified using biological methods which, however, tend to be costly and time-consuming due to the vast number of sub-sequences to experiment on. In this paper, we study the problem from a computational per-spective and propose a computing method to identify the SSS. Given DNA sequences of a tar-get species, some of which are known to contain a TT while others not, our method uses machine learning techniques and is done in three steps. First, we find all frequent subsequences from the given sequences, and show that this can be effi-ciently done using generalized suffix trees. Sec-ond, we use these subsequences as features to characterize the original DNA sequences and train a classification model using Support Vector Machines (SVM), one of the currently most effec-tive machine learning techniques. Using the pa-rameters of the resulting SVM model, we define a measure called subsequence specificity to rank the frequent subsequences, and output the one with the highest rank as the SSS. Our experi-ments show that the SSS found by the proposed method are very close to those determined by biological experiments. This suggests that our method, though purely computational, can help efficiently locate the SSS by effectively narrowing down the search space.
The Use of Rank-sum Ratio on the Attack and Defensive Ability of the Top 8 Men’s Basketball Competition in the 16th Asian Games
Yi LIU,Lei GU
Management Science and Engineering , 2012, DOI: 10.3968/j.mse.1913035x20120601.z5r008
Abstract: Aim: This essay focuses on the attack and defensive ability of the top 8 men’s basketball teams in the 16th Asian Games. The authors try to compare their characters and find out problems. Methods: Documentation analysis, Rank-sum ratio and related analysis have been used in this report. According to this report, it is found that in the TOP 8, China owns the highest Offensive Ability RSR Level, The Jordan have the lowest. If, on the other hand, the South Korea is the highest team in Defensive ability RSR level, the North Korea team is the lowest. From the aspects of Integrating Offensive and Defensive ability RSR level, the South Korea is still the highest and the North Korea is the lowest. Considering the Integrating Offensive and Defensive ability RSR, the authors divided the TOP 8 into 3 levels. China and South Korea are the superiors. They own the strongest Offensive and Defensive Ability. North Korea is in lower class, this class is weak in TOP 8. Jordan, the Philippines, Qatar, Japan, Iran are in the middle class. The coaches can adjust their training plans with pertinence, according to the statistics on Offensive and Defensive Ability showed in this Asian Game. The author hopes this research can offer a reference in the training. Key words: The 16th Asian Games; Men’s Basketball; Attack Defense; Rank-sum ratio
Sociodemographic Effects on the Onset and Recovery of ADL Disability among Chinese Oldest-old
Gu Danan,Zeng Yi
Demographic Research , 2004,
Abstract: By pooling the data from the three waves (1998, 2000, and 2002) of the Chinese Longitudinal Health and Longevity Survey, this study examines the association of sociodemographic factors with the onset and recovery of ADL disability including changes in functional status before dying. The results show that the sociodemographic factors play some specific roles in disability dynamics at very high ages even after controlling for a rich set of confounders. Our results also point out that the conventional method, which excludes the information of ADL changes before dying due to unavailability of the data, overestimates the effects of age, gender, ethnicity, and living alone on disability transitions whereas it underestimates the effects of SES, although such discrepancies are not very big compared with the results including information of ADL changes before dying.
PHENIX Measurements of Higher-order Flow Harmonics for Identified Charged Hadrons in Au+Au collisions at $\sqrt{s_{NN}}=39-200$ GeV
Yi Gu,for the PHENIX Collaboration
Physics , 2012, DOI: 10.1016/j.nuclphysa.2013.02.022
Abstract: The azimuthal anisotropy coefficients $v_{2,3,4}$, characterizing collective flow in Au+Au collisions, are presented for identified particle species as a function of transverse momentum ($p_T$), centrality ($\rm{cent}$) and beam collision energy ($\sqrt{s_{NN}}=0.039-0.20$ TeV). The $v_n$ values for each particle species, show little, if any, change over the measured beam energy range, and ${v_n}/{(n_q)^{n/2}}$ vs. $KE_T/n_q$ scales to a single curve (constituent quark number ($n_q)$ scaling) for each $n$, over a broad range of transverse kinetic energies ($KE_T$). A comparison of $v_2(p_T)$ for individual particle species obtained in Au+Au collisions at $\sqrt{s_{NN}}=0.20$ TeV (RHIC) and Pb+Pb collisions at $\sqrt{s_{NN}}=2.76$ TeV (LHC), indicate stronger collective flow at the LHC. These flow measurements and their scaling patterns, can provide important additional constraints for extraction of the specific viscosity $\eta/s$.
CEI: a new indicator measuring City Commercial Credit Risk initiated in China
Ruonan Lin,Yi Gu
Quantitative Finance , 2015,
Abstract: Aiming at quantifying and evaluating the regional commercial environment along with the level of economic development among cities in mainland China, the concept of China City Commercial Environment Credit Index(CEI) was first introduced and established in 2010. In this manuscript, a historical review and detailed introduction of CEI is included, followed by statistical studies. In particular, an independent statistical cross-check for the existing CEI-2012 is performed and significant factors that play the most in influential roles are discussed.
An image analysis method for quantification of hepatic perfusion based on contrast-enhanced ultrasound imaging  [PDF]
Yi-xin Li, Fang Yang, Ning Gu
Journal of Biomedical Science and Engineering (JBiSE) , 2008, DOI: 10.4236/jbise.2008.12019
Abstract: Information about hepatic perfusion is used in clinical liver disease diagnosis. An image analy-sis system can help physicians make efficient and accurate diagnosis. The objective of this study is to propose an image analysis method for the quantification of the hepatic perfusion based on contrast-enhanced ultrasound imaging (CEUI). The proposed method contains frame selection, image registration, digital subtraction and grey-scale calculation. Then, by processing an image sequence, a time-intensity curve (TIC) for hepatic perfusion is derived. The kernel of this image analysis technology is digital subtrac-tion and its accuracy is improved by frame selec-tion and image registration. The advantage of this method is that it can obtain the perfusion information of the whole liver which is rarely ob-tained by traditional image analysis technology; therefore, it is a supplement of the traditional image analysis method. This method is applied on the quantification of a rabbit’s hepatic perfu-sion and the result shows the efficiency of it.
Fabrication of Si-PDMS Low Voltage Capillary Electrophoresis Chip  [PDF]
Wenwen GU, Zhiyu WEN, Zhongquan WEN, Yi XU, Fengfei LIANG, Xiaoguo HU
Engineering (ENG) , 2009, DOI: 10.4236/eng.2009.12013
Abstract: This paper discusses the fabrication of Si-PDMS low voltage capillary electrophoresis chip (CE chip). Arrayed-electrode which is used to apply low separation voltage is fabricated along the sidewalls of the separation channel on the silicon based bottom part. Isolation trenches, which are placed surrounding the arrayed-electrode, insure the insulation between the arrayed-electrode, as well as arrayed-electrode and liquid in the micro channel. Polydimethylsilicone (PDMS) is used as the cover. PDMS and silicon based bottom part are reversible sealed to attain Si-PDMS low voltage CE chip. Experiments have been done to obtain optimum electrophoresis separation condition: separation voltage is 45V, switch time is 2s and the Phe and Lys electrophoresis separation is successful.
Influence of Modifier in Supercritical CO2 on Qualitative and Quantitative Extraction Results of Eucalyptus Ecential Oil  [PDF]
Wenyang Dai, Soulisith Keokurngsamay, Yuan Chen, Xiao Zhu, Lili Gu, Yi Han, Zhijun Li
American Journal of Plant Sciences (AJPS) , 2018, DOI: 10.4236/ajps.2018.92014
Abstract: A supercritical CO2 extraction behavior of Eucalyptus oil was investigated under different conditions of pressure, temperature and time with or without cosolvent. The pressure range was from 8 to 25 MPa, temperature from 35 to 55°C and CO2 flow rate from 10 to 26 g/min. For 1,8-cineole the appropriate extracting pressure was 15 MPa and temperature was 45°C. When CO2 flow rate was 18 g/min, it was benefit to extract the other three substances (limonene, p-cymene and γ-terpinene, respectively) except 1,8-cineole. Prolonging extraction time could not obviously increase the extract concentration, but the extract yield would increase. The results also indicated that ethanol as a modifier could improve extraction velocity and extraction concentration.
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