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This research utilizes a descriptive research design to investigate the use of vocabulary learning strategies among English majors and identify the potential reasons for their difficulties in learning vocabulary. The study aims to describe the relationship between these reasons and second language vocabulary acquisition. A questionnaire, consisting of 62 items selected from the Vocabulary Learning Questionnaire (VLQ) 6.4 published by Gu and Johnson (1996), was administered to 115 sophomores majoring in English. The questionnaire was used to determine the types of vocabulary learning strategies employed by the participants, as well as the most and least frequently used strategies. The results indicate that English majors surveyed were moderate users of vocabulary learning strategies. Inferencing strategies were found to be the most commonly used, while Encoding strategies were the least used. After analyzing the participants' vocabulary learning strategies, the study proposes to improve their mother tongue competence to enhance their thinking ability, which is an essential factor in learning English vocabulary. Furthermore, the study suggests that the lack of mother tongue competence courses in higher education and the absence of effective vocabulary learning strategy guidance in the learning process are potential reasons for the difficulties experienced by English majors in vocabulary learning.

Free trial strategy, which allows a user to use service/product freely for a limited time, is widely applied in online service. With time-based pricing, we first consider that the service provider launches its initial version and offers a fixed length of free trial. We observe that the optimal length of free trial cannot be more than 1/3 of the initial version's lifespan. Then, we analyze the two-stage setting where a strategic or myopic service provider (SP) upgrades its initial version in the second stage with another fixed length of free trial. The findings show that the optimal length of free trial becomes shorter if a strategic SP sets the same price in two stages. When the paying users in the first stage pay the same for both the initial and the upgraded versions, the upgraded version has a shorter length of free trial and a lower price, which is counter-intuitive. For a myopic SP, the upgraded version has a longer length of free trial and a higher price. The above findings are insightful for the operation of online service.

Streptozotocin (STZ) is a pancreatic β cell-specific toxicant that is widely used to generate models of diabetes in rodents as well as in the treatment of tumors derived from pancreatic β cells. DNA alkylation, oxidative stress and mitochondrial toxicity have been recognized as the mechanisms for STZ-induced pancreatic β cell damage. Here, we found that pancreatic β cell-specific deficiency of nuclear factor erythroid-derived factor 2-related factor 1 (NFE2L1), a master regulator of the cellular adaptive response to a variety of stresses, in mice led to a dramatic resistance to STZ-induced hyperglycemia. Indeed, fifteen days subsequent to last dosage of STZ, the pancreatic β cell specific Nfe2l1 knockout [Nfe2l1(β)-KO] mice showed reduced hyperglycemia, improved glucose tolerance, higher plasma insulin and more intact islets surrounded by exocrine acini compared to the Nfe2l1-Flox control mice with the same treatment. Immunohistochemistry staining revealed a greater amount of insulin-positive cells in the pancreas of Nfe2l1(β)-KO mice than those in Nfe2l1-Flox mice 15 days after the last STZ injection. In line with this observation, both isolated Nfe2l1(β)-KO islets and Nfe2l1-deficient MIN6 (Nfe2l1-KD) cells were resistant to STZ-induced toxicity and apoptosis. Furthermore, pretreatment of the MIN6 cells with glycolysis inhibitor 2-Deoxyglucose sensitized Nfe2l1-KD cells to STZ-induced toxicity. These findings demonstrated that loss of Nfe2l1 attenuates pancreatic β cells damage and dysfunction caused by STZ exposure, partially due to Nfe2l1 deficiency-induced metabolic switch to enhanced glycolysis.

As more and more spacecraft launched into the space, the probability of radiofrequency (RF) interference raises and the burden of RF spectrum management increases as well. The monitoring of global RF beam information and identifying of spot beam emitters location can effectively obtain space data resources, which will do great help for mitigating global RF interference and optimising space spectrum resources. This study proposes a novel location awareness method for spot beam emitters based on the nanosatellite platform. The proposed method identifies the position of spot beam emitters on a global scale by flying a low earth orbit CubeSat constellation through the coverage of the spot beams. The properties such as geometry, the target motion equation, the measurement process, and the Particle Filter equations are all addressed with respect to the location methods. The authors illustrate a realistic scenario simulated within the Systems Tool Kit, in which CubeSats receive signals from the spot beam emitters. The scenario shows that their location awareness method proposed in this study is available and efficient.

Cadmium (Cd) is a heavy metal pollutant that adversely effects the kidney. Oxidative stress and inflammation are likely major mechanisms of Cd-induced kidney injury. Nuclear factor (erythroid-derived 2)-like 2 (Nrf2) is crucial in regulating antioxidant and inflammatory responses. To investigate the role of Nrf2 in the development of subacute Cd-induced renal injury, we utilized Nrf2 knockout (Nrf2-KO) and control mice (Nrf2-WT) which were given cadmium chloride (CdCl2, 1 or 2 mg/kg i.p.) once daily for 7 days. While subacute CdCl2 exposure induced kidney injury in a dose-dependent manner, after the higher Cd dosage exposure, Nrf2-KO mice showed elevated blood urea nitrogen (BUN) and urinary neutrophil gelatinase-associated lipocalin (NGAL) levels compared to control. In line with the findings, the renal tubule injury caused by 2 mg Cd/kg, but not lower dosage, in Nrf2-KO mice determined by Periodic acid–Schiff staining was more serious than that in control mice. Further mechanistic studies showed that Nrf2-KO mice had more apoptotic cells and severe oxidative stress and inflammation in the renal tubules in response to Cd exposures. Although there were no significant differences in Cd contents of tissues between Cd-exposed Nrf2-WT and Nrf2-KO mice, the mRNA expression of Nrf2 downstream genes, including heme oxygenase 1 and metallothionein 1, were significantly less induced by Cd exposures in the kidney of Nrf2-KO compared with Nrf2-WT mice. In conclusion, Nrf2-deficient mice are more sensitive to kidney injury induced by subacute Cd exposure due to a muted antioxidant response, as well as a likely diminished production of specific Cd detoxification metallothioneins.

To understand the occupational stress and sub-health level of pharmaceutical marketers in Northeast China, and to analyze their influencing factors and the impact of occupational stress on sub-health.From October to December in 2016, we conducted a questionnaire survey about occupational stress and sub-health status of 698 women and 454 men pharmaceutical marketers aged from 22 to 58 years old in northeast China.The rate of occupational stress was 86. 9%. The top 3 stressors with higher scores were the pressure brought about by the intensification of social competition(2. 90±1. 017), the higher standards of job assessment and the great efforts needed by individuals(2. 90±0. 959). The detection rate of sub-health was 82. 1%. There were statistically differences in the rate of sub-health detection among the groups of different genders(χ~2=4. 726, P=0. 030) and different business types(χ~2=7. 961, P=0. 047). There were statistically significant differences in the rate of different ages(χ~2=9. 534, P=0. 009), different marital status(χ~2=7. 010, P=0. 008), different working years(χ~2=18. 082, Plt;0. 001), and different stress groups(χ~2=152. 565, Plt;0. 001). Multivariate analysis showed that occupational stress is the key factor affecting sub-health. Mild stress(OR=0. 076, 95%CI 0. 040-0. 143)and moderate stress(OR=0. 348, 95%CI 0. 189-0. 641)are the protected factors of sub-health.The occupational stress rate and sub-health detection rate of medical marketers were both higher. Relieving the pressure of pharmaceutical marketers effectively can improve their sub-health status.

One-lung ventilation (OLV) is essential in numerous clinical procedures, in which the left-sided double-lumen tube (LDLT) is the most commonly used device. The application of bronchial blockers, including the Uniblocker or Arndt blocker, has increased in OLV. The present study aimed to compare the efficacy and adverse effects of the Uniblocker and LDLT for OLV under the guidance of chest CT. A total of 60 adult patients undergoing elective left-side thoracic surgery requiring OLV were included in the study. The patients were randomly assigned to the Uniblocker group (U group, n=30) or the LDLT group (D group, n=30). The time for initial tube placement, the number of optimal positions of the tube upon blind insertion, the number of attempts to adjust the tube to the optimal position, incidence of airway device displacement, injury to the bronchi and carina, the duration until lung collapse and the occurrence of sore throat and hoarseness over 24 h following surgery were recorded. The time for successful placement of the LDLT was 83.9±19.4 sec and that for the Uniblocker was 84.3±17.1 sec (P>0.05). The degree of lung collapse 1 min following opening of the pleura was greater in the D group than that in the U group (P

We study network resource allocation under information asymmetry, i.e., users have private information regarding their utility functions. The service provider would like to design an incentive-compatible pricing scheme to maximize the social welfare. It is well known that there is a market mechanism for the network resource allocation achieving the first best under complete information. Under the market mechanism, the service provider only needs to decide on the resource allocation to maximize the aggregate surrogate utility of the users. However, user utility information is typically private in practice. With the information asymmetry, we propose a novel dynamic auction mechanism. Under our dynamic auction, the users must follow the monotone activity rule in the bidding process and the auctioneer updates the prices based on the submitted bids by maximizing the aggregate surrogate utility. Surprisingly, our dynamic auction mechanism is a first-best dominant-strategy incentive compatible mechanism. In particular, the equilibrium outcome is the same as the market equilibrium and budget-balanced. The auctioneer does not need the utility information of the users, i.e., the auction is robust to the user utility information.This is possible by exploiting of the aggregate surrogate utility maximization of the auctioneer and the monotone activity rule we imposed. Thus, our dynamic auction mechanism is practical as it is simple, detail-free and privacy preserving, enriching the mechanism design theory. Finally, our results can be potentially applied to other network resource allocation problems.

We consider a periodic review, joint inventory and pricing control problem for a firm that faces general random price‐dependent demands. Any unsatisfied demand can be either backordered or lost immediately. The objective is to maximize the expected profit over a finite selling horizon by coordinating the inventory and pricing decisions in each period. For both the backorder model and the lost sales model, we derive some quite general sufficient conditions to ensure the optimality of a base‐stock list price (BSLP) policy based on the strict monotonicity of demand functions in the realizations of random noises. We are among the first to utilize the strict monotonicity of demand functions in the realizations of random noises for deriving the sufficient conditions. We derive the sufficient conditions in both the backorder model and the lost‐sales model by utilizing the new concept of upper‐set and lower‐set decreasing properties (USDP/LSDP), which is a generalized version of the first‐order stochastic dominance. This study reveals that the optimality of a BSLP policy is robust to more general business environments than what we previously thought. Finally, we also apply the USDP/LSDP in other inventory management problems.

In this paper, we study a dynamic inventory rationing problem of a single item with multiple demand classes and backorder. Demand classes are differentiated by their unit backlogging costs. The corresponding dynamic programming problem is multidimensional and computationally challenging. With a novel state transformation, we find that the optimal policy can be described by a nested base stock policy. In particular, we can decompose the value function as the sum of single-variable convex functions. This property breaks the curse of dimensionality and significantly reduces computational effort in computing optimal policies. Our approach allows us to extend the results to systems with ordering, exogenous supply, priority upgrading.

The synthesis of high activity TiO2–CTAB–SiC composite possessing the microwave absorption capacity has been reported. Herein, the commercial Silicon carbide (SiC) particles were used as the microwave absorbent and supporter. TiO2 nanopowders were loaded on the surface of SiC modified by hexadecyl trimethyl ammonium bromide (CTAB) via the hydrothermal route. The as-prepared TiO2–CTAB–SiC composite was characterized by X-ray diffraction, field-emission scanning electron microscopy, Fourier transformed infrared spectra, inductively coupled plasma-atomic emission spectrometry and fluorescence emission (PL). Its photocatalytic activity was evaluated by the degradation of rhodamine B in the microwave discharge electrodeless lamp (MDEL) system. The experimental results showed that TiO2–CTAB–SiC composite exhibited obviously higher photocatalytic activity in the MDEL system compared with pure TiO2 nanopowders. Their reusability and separation performance were evaluated by recycling experiments. The reasons for the improvement in photocatalytic performance were discussed in detail.

Direct value identification refers to the consumer-perceived value for a product itself. In the era of We-Media, consumers may also have indirect value identification for a product which stems from their fondness and emotional identification for some key opinion leaders (KOLs). To investigate the possible impacts of indirect value identification on product-selling strategy, and further explore the potential power of KOLs in green-product marketing, this paper analyzes the optimal product-selling strategy under direct and indirect value identification for firms producing and selling regular or green products. Results show that the optimal product-selling strategy is affected by the two kinds of value identification in a relatively independent way. Specifically, the fraction of followers in the whole consumer population and the relative marketing cost of KOLs affect the selling strategy while the marginal green production cost decides the product strategy.

Ground state properties and level statistics of the Dicke model for a finite number of atoms are investigated based on a progressive diagonalization scheme (PDS). Particle number statistics, the entanglement measure and the Shannon information entropy at the resonance point in cases with a finite number of atoms as functions of the coupling parameter are calculated. It is shown that the entanglement measure defined in terms of the normalized von Neumann entropy of the reduced density matrix of the atoms reaches its maximum value at the critical point of the quantum phase transition where the system is most chaotic. Noticeable change in the Shannon information entropy near or at the critical point of the quantum phase transition is also observed. In addition, the quantum phase transition may be observed not only in the ground state mean photon number and the ground state atomic inversion as shown previously, but also in fluctuations of these two quantities in the ground state, especially in the atomic inversion fluctuation.

We present a detailed study of the computational complexity of a numerical algorithm based on the Heine–Stieltjes correspondence following the new approach we proposed recently for solving the Bethe ansatz (Gaudin–Richardson) equations of the standard pairing problem. For k pairs of valence nucleons in n non-degenerate single-particle energy levels, the approach utilizes that solutions of the Bethe ansatz equations can be obtained from two matrices of dimensions ( k + 1 ) × ( k + 1 ) and ( n − 1 ) × ( k + 1 ) , which are associated with the extended Heine–Stieltjes and Van Vleck polynomials, respectively. Since the coefficients in these polynomials are free from divergence with variations in contrast to the original Bethe ansatz equations, the approach provides an efficient and systematic way to solve the problem. The method reduces to solving a system of k polynomial equations, which can be efficiently implemented by the fast Newton–Raphson algorithm with a Monte Carlo sampling procedure for the initial guesses. By extension, the present algorithm can also be used to solve a large class of Gaudin-type quantum many-body problems, including an efficient angular momentum projection method for multi-particle systems. Program summary Program title: exactPairingHS Catalogue identifier: AETD_v1_0 Program summary URL: http://cpc.cs.qub.ac.uk/summaries/AETD_v1_0.html Program obtainable from: CPC Program Library, Queen’s University, Belfast, N. Ireland Licensing provisions: Standard CPC licence, http://cpc.cs.qub.ac.uk/licence/licence.html No. of lines in distributed program, including test data, etc.: 5411 No. of bytes in distributed program, including test data, etc.: 39758 Distribution format: tar.gz Programming language: Mathematica. Computer: Laptop, workstation. Operating system: Tested with MATHEMATICA version 9.0 on Mac OS X and Windows 7. RAM: Less than 10 MB Classification: 17.15. Nature of problem: The program calculates exact pairing energies based on the Heine–Stieltjes polynomial approach. Existing conventional exact-pairing approaches require solving systems of highly nonlinear equations, which are difficult and often impossible to solve beyond the simplest of the quantum-mechanical many-particle systems. In this study, the Heine–Stieltjes polynomial approach is employed to provide solutions for more than one or two pairs of particles residing in many energy levels. Solution method: The new Heine–Stieltjes polynomial approach transforms the pairing problem to one that involves the handling of only two matrix equations. This, combined with an efficient numerical algorithm implemented by the fast Newton–Raphson method with a Monte Carlo sampling procedure for the initial guesses, makes exact pairing solutions feasible even when more energy levels or heavy nuclei (many pairs) are considered. Running time: Less than a hundred seconds using a 2.80 GHz processor. The notebook takes approximately 23 min to complete.

Background: The use of bronchial blockers has been increased for one-lung ventilation; however, the placement of bronchial blockers is time consuming. The objective of this study was to compare the novel extraluminal technique of Uniblocker placement supported by trachea length measurement on computerized tomography images with conventional intraluminal Uniblocker placement method. Methods: Seventy adult patients undergoing left side thoracic surgery were included in the study. All the patients were randomly assigned to one of two groups: conventional intraluminal intubation group (CV-IN group, n = 35) or extraluminal CT guided group (CT-EX group, n = 35). The primary endpoints were the optimal positions of Uniblocker and the injuries of bronchi and carina. The secondary outcomes included the time of Uniblocker placement, the adequacy of lung collapse, the incidences of Uniblocker displacement, sore throat, and hoarseness postoperative. Results: In the CV-IN group, 19 of 35 Uniblockers went to the left main-stem bronchus on the initial blind insertion and 15 of 35 Uniblockers were considered as in optimal depth, whereas in the CT-EX group, 32 of 35 Uniblockers went to the left main-stem bronchus on the initial blind insertion and 31 of 35 Uniblockers were considered as in optimal depth (P .05). Conclusion: The novel extraluminal technique of Uniblocker placement supported by trachea length measurement on computerized tomography images was proved to be more rapid, more accurate and less complications than conventional intraluminal Uniblocker placement method.

Fe3O4@polypyrrole (PPy) hollow capsules were prepared by hard-template method in a simple way, where construction of the PPy shell and formation of the Fe3O4 nanoparticles were combined into one st...

A progressive diagonalization scheme for the Dicke Hamiltonian, which describes the interaction of N two-level atoms with a single-mode radiation field via a dipole interaction, is proposed. It is shown that the ground state of the Dicke Hamiltonian with a finite number of atoms can be solved almost exactly by using a progressive diagonalization scheme that involves a one-variable equation at each step. The scheme is efficient for the lower part of the spectrum. Calculated results for ground-state energies, photon numbers, atomic inversions, fluctuations in the latter two quantities, entanglement measures, and Shanon information entropies at resonance points for some finite j cases as functions of the coupling parameter are given. These outcomes show significant changes in the photon number, atomic inversion, and their fluctuations near the critical point where the entanglement measure reaches its maximum value.

Quantum phase transitions in nuclei have attracted a lot of attention from both experimental and theoretical perspectives [1‐25], since they provide new insights into understanding the evolution of nuclear properties. The quantum phase transition is not of the usual thermodynamic type, but relat ed to the equilibrium shape changes in the ground state of nuclei at zero temperature. It is thus also referred to as the shape phase transition or ground state phase transition, though t he concept can also be applied to excited states. Evidences of the shape phase transition in nuclei are signaled experimentally through a sudden change in the properties of the ground state. An excellent example is provided by a set of even Sm isotopes, of which the evolution of its properties can be identified as t he first-order shape phase phase transition experimentally [2 2]. On the other hand, odd-A nuclei can be approximately considered as systems with an even-even core coupled to a single valence nucleon. It is thus expected that the properties of odd-A nuclei should be definitely affected by the shape phase transition emerging along the related odd isotope or isotone chains. Currently, analyses of the phase transitions in nuclei are mostly focused on even-even systems and have been carried out in the frame of phenomenological geometrical models of nuclear potential [1, 2], or algebraic models of nuclear str ucture [25] since the phase transitions in the intermediate an d heavy mass region, such as the mass number A ∼ 150 region, are often out of reach of the microscopic shell models. In addition, phase transitions in odd-A nuclei may be more difficult to describe due to much more complicate dynamical situations [26] in contrast to the adjacent even-even speci es. However, if one only wants to emphasize some special aspects of nuclear phase transitions, the shell model (under some approximations) is still applicable to give a microscopic ana lysis of the phase transition in the A ∼ 150 region. The purpose of this work is to give a microscopic analysis of the shape phase transition in the odd Sm nuclei in terms of the effective order parameters and odd-even effects.

An efficient numerical progressive diagonalization scheme for the quantum Rabi model is revisited. The advantage of the scheme lies in the fact that the quantum Rabi model can be solved almost exactly by using the scheme that only involves a finite set of one variable polynomial equations. The scheme is especially efficient for a specified eigenstate of the model, for example, the ground state. Some low-lying level energies of the model for several sets of parameters are calculated, of which one set of the results is compared to that obtained from the Braak's exact solution proposed recently. It is shown that the derivative of the entanglement measure defined in terms of the reduced von Neumann entropy with respect to the coupling parameter does reach the maximum near the critical point deduced from the classical limit of the Dicke model, which may provide a probe of the critical point of the crossover in finite quantum many-body systems, such as that in the quantum Rabi model.

A recursive method for the construction of symmetric irreducible representations of $ O(2l+1)$ in the $ O(2l+1)\supset O(3)$ basis for identical boson systems is proposed. The formalism is realized based on the group chain $ U(2l+1)\supset U(2l-1)\otimes U(2)$ , of which the symmetric irreducible representations are simply reducible. The basis vectors for symmetric irreducible representations of the $ O(2l+1)\supset O(2l-1)\otimes U(1)$ can easily be constructed from those of U(2l + 1) $ \supset$ U(2l - 1) ⊗ U(2) $ \supset$ O(2l - 1) ⊗ U(1) with no l -boson pairs, namely with the total boson number exactly equal to the seniority number in the system, from which one can construct symmetric irreducible representations of $ O(2l+1)$ in the $ O(2l-1)\otimes U(1)$ basis when all symmetric irreducible representations of O(2l - 1) are known. As a starting point, basis vectors of symmetric irreducible representations of O(5) are constructed in the $ O_{1}(3)\otimes U(1)$ basis, where $ O_{1}(3)\equiv O(2l-1)$ , when l = 2 , which is generated not by the angular momentum operators of the d -boson system, but by the operators constructed from d -boson creation (annihilation) operators $ d^{\dagger}_{\mu}$ ( $ d_{\mu}$ with $ \mu=1$ , 0, -1 . Matrix representations of $ O(5)\supset O_{1}(3)\otimes U(1)$ , together with the elementary Wigner coefficients, are presented. After the angular momentum projection, a three-term relation in determining the expansion coefficients of the $ O(5)\supset O(3)$ basis vectors, where the O(3) group is generated by the angular momentum operators of the d -boson system, in terms of those of $ O_{1}(3)\otimes U(1)$ is derived. The eigenvectors of the projection matrix with zero eigenvalues constructed according to the three-term relation completely determine the basis vectors of $ O(5)\supset O(3)$ . Formulae for evaluating the elementary Wigner coefficients of $ O(5)\supset O(3)$ are derived explicitly. Analytical expressions of some elementary Wigner coefficients of $ O(5)\supset O(3)$ for the coupling $ (\tau 0)\otimes(1 0)$ with resultant angular momentum quantum number L = 2 $ \tau$ + 2 - k for $ k=0,2,3,\ldots,6$ with a multiplicity 2 case for k = 6 are presented.

Ground-state phase transitions in odd nuclei are examined. Especially, the phase transitions in odd-odd nuclei are revealed. It is found that odd-even effects may reach their maximal or minimal values around the critical point at $N=90$; the signals of phase transition in odd nuclei are greatly enhanced relative to those in the adjacent even-even species. Moreover, a pairing model analysis of the phase transition in Sm isotopes indicates that the critical behaviors related to pairing may be driven by the decrease in the pair strength $G$ with a sudden flattening in $\ensuremath{\Delta}G$ around the critical point.

Extreme learning machine is a new learning algorithm for the single hidden layer feedforward neural networks (SLFNs). ELM has been widely used in various fields and applications to overcome the slow training speed and over-fitting problems of the conventional neural network learning algorithms. ELM algorithm is based on the empirical risk minimization, without considering the structural risk and this may lead to over-fitting problems and at the same time, it is with poor controllability and robustness. For these deficiencies, an optimization method is proposed in this paper, a novel extreme learning machine based on hybrid kernel function (HKELM). The method constructs a hybrid kernel function with better performance by fully combining local kernel function strong learning ability and global kernel function strong generalization ability. Compared with traditional ELM, the results show that this method can effectively improve the ELM classification results, avoid local minimum, with better generalization, robustness, controllability and faster learning rate.

For high dimensional data, the redundant attributes of samplers will not only increase the complexity of the calculation, but also affect the accuracy of final result. The existing attribute reduction methods are encountering bottleneck problem of timeliness and spatiality. In order to looking for a relatively coarse attributes granularity of problem solving, this paper proposes an efficient attribute granulation method to remove redundancy attribute. The method calculates the similarity of attributes according attribute discernibility first, and then clusters attributes into several group through affinity propagation clustering algorithm. At last, representative attributes are produced through some algorithms to form a coarser attribute granularity. Experimental results show that the attribute granulation method based on affinity propagation clustering algorithm(AGAP) method is a more efficient algorithm than traditional attribute reduction algorithm(AR).

In the 21st century, the era of big data comes out as the world enters the era of data explosion. It requires a large-scale parallel processing system, just like cloud computing, to deal with the various and massive data quickly and efficiently. Cloud computing is a computing paradigm that is not only a collection of distributed computing, parallel computing and grid computing, but also suitable for handling large-scale data. This paper mainly introduces the definition, characteristics, service models and deployment models of cloud computing. Afterwards, some security challenges that cloud computing faces are presented. Finally, a brief summary and outlook of cloud computing are given.

A new approach for solving the Bethe ansatz (Gaudin-Richardson) equations of the standard pairing problem is established based on the Heine-Stieltjes correspondence. For $k$ pairs of valence nucleons on $n$ different single-particle levels, it is found that solutions of the Bethe ansatz equations can be obtained from one (k+1)x(k+1) and one (n-1)x(k+1) matrices, which are associated with the extended Heine-Stieltjes and Van Vleck polynomials, respectively. Since the coefficients in these polynomials are free from divergence with variations in contrast to the original Bethe ansatz equations, the approach thus provides with a new efficient and systematic way to solve the problem, which, by extension, can also be used to solve a large class of Gaudin-type quantum many-body problems and to establish a new efficient angular momentum projection method for multi-particle systems., Comment: ReVTeX, 4 pages, no figure

New polynomials associated with a special Lipkin-Meshkov-Glick (LMG) model corresponding to the standard two-site Bose-Hubbard model are derived based on the Stieltjes correspondence. It is shown that there is a one-to-one correspondence between zeros of this new polynomial and solutions of the Bethe ansatz equations for the LMG model.A one-dimensional classical electrostatic analogue corresponding to the special LMG model is established according to Stieltjes early work. It shows that any possible configuration of equilibrium positions of the charges in the electrostatic problem corresponds uniquely to one set of roots of the Bethe ansatz equations for the LMG model, and the number of possible configurations of equilibrium positions of the charges equals exactly to the number of energy levels in the LMG model. Some relations of sums of powers and inverse powers of zeros of the new polynomials related to the eigenenergies of the LMG model are derived., 11 pages, LaTeX

In the era of knowledge economy, critical knowledge and technologies are key to enterprise competition. Huawei and ZTE are well known as top Chinese communication equipment suppliers. Both have paid great attention to intellectual property protection, and have applied a great amount of patents in information and communication technology. In this article, patent analysis is used to figure out whether there exists difference between Huawei and ZTE in technology research and development. The results show the patent portfolios of them are similar but difference exists. During the period 2006–2012, ZTE performed better than Huawei on the whole.