保险享有能缓解农民工过度劳动吗?

我国农民工群体的工作时间普遍过长,存在过度劳动问题。本文基于2016和2017年中国乡城人口流动调查数据,建立了农民工过度劳动选择和过度劳动时间面板固定效应模型,实证研究了保险享有对农民工群体过度劳动的影响。研究结果显示,保险享有能够有效降低农民工群体过度劳动的概率,有助于缩减该群体过度劳动及重度过度劳动的时间。据此,为有效缓解农民工群体的过度劳动,政府部门在严格限制劳动者的工作时间和规范加班工资制度的同时,还应采取措施保证农民工群体享有基本保险。

频谱音乐的曲式原则

曲式通常表示音乐的"时空结构",频谱音乐对此的最大贡献是通过仪器分析,频谱显现,使得这本来属于纯理论范畴的内容,成为了一种可视的、具有生命力的"视在声源"。自此,我们不仅可以用文本分析去了解曲式,用耳朵去感受曲式,还增加了一种重要的方法———用眼睛去实事观察声音状态由生到死的变化全过程。文章从时间过渡性原则、自我繁殖与自我破坏(阻断)原则、可预测与不可预测原则,以及协和序进原则等四个方面,对频谱音乐的曲式领域进行研究。

The Neglected Significance of Glomerular Density as a 5-year Progression Indicator for IgA Nephropathy

Objective To investigate whether glomerular density （GD） could be an independent prognostic factor for patients of IgA nephropathy with estimated glomerular filtration rate （eGFR） of 30 to 60 ml/min per 1.73 m2, or for patients with time-average proteinuria 〈 0.5 g/d. Methods A total of 173 patients with biopsy-confirmed IgA nephropathy diagnosed from January 2000 to December 2010 were included. All of these patients were followed up for more than 5 years. The endpoint was a 〉 30% of decline in eGFR from baseline after 5-year follow-up. The optimal cut-off value of GD was calculated by ROC curve. Kaplan-Meier method and Cox regression analysis was used for survival analysis. Results A 30% of decline in eGFR occurred in 14.5% of all patients. The optimal diagnostic cut-off value of GD was 1.99/mm2 （AUC = 0.90, sensitivity = 84.0%, specificity = 81.8%） determined by ROC curve. The low GD group （GD 〈 1.99 per mm2） experienced a significant increase in renal endpoint for patients with eGFR of 30 to 60 ml/min per 1.73 m2 （six patients in lower GD group, while one patient in the other group）. For patients with time-average proteinuria 〈 0.5 g/d, the lower GD group showed a higher eGFR decline from baseline （4.5±16.7 ml/min per 1.73 m2 vs. –8.1±21.4 ml/min per 1.73 m2, P = 0.038）; two patients in this group reached the endpoint, while no patients in the higher GD group did. Conclusion GD could be an independent prognostic factor for patients of IgA nephropathy with eGFR at 30 to 60 ml/min per 1.73 m2 of body surface, particularly for those with time-averaged amount of urine protein less than 0.5 g per day.

连铸混浇坯的过度时间及影响因素

为提高连铸比实现全连铸，鞍钢二炼钢在小方坯连浇不同钢种过渡段铸坯成分差异上做了试验研究，并指出小方坯连铸机增设钢水快速分析和快速调节装置的必要性。

Multiscale entropy:A tool for understanding the complexity of postural control

Clinical disorders often are characterized by a breakdown in dynamical processes that contribute to the control of upright standing.Disruption to a large number of physiological processes operating at different time scales can lead to alterations in postural center of pressure(Co P)fluctuations.Multiscale entropy(MSE) has been used to identify differences in fluctuations of postural Co P time series between groups with and without known physiological impairments at multiple time scales.The purpose of this paper is to:1) review basic elements and current developments in entropy techniques used to assess physiological complexity;and 2) identify how MSE can provide insights into the complexity of physiological systems operating at multiple time scales that underlie the control of posture.We review and synthesize evidence from the literature providing support for MSE as a valuable tool to evaluate the breakdown in the physiological processes that accompany changes due to aging and disease in postural control.This evidence emerges from observed lower MSE values in individuals with multiple sclerosis,idiopathic scoliosis,and in older individuals with sensory impairments.Finally,we suggest some future applications of MSE that will allow for further insight into how physiological deficits impact the complexity of postural fluctuations;this information may improve the development and evaluation of new therapeutic interventions.

Determination of metastable zone and induction time of analgin for cooling crystallization

The solubility, metastable zone width, and induction time of analgin for unseeded batch cooling crystallization in ethanol–aqueous system were experimentally determined. The solubility data could be well described by the van't Hoff equation model. The metastable zone width at various cooling rates was measured, and some parameters of nucleation kinetic were calculated using the Ny'vlt theory. Furthermore, the induction period of various temperatures and supersaturation ratios was also measured. According to classical nucleation theory, some nucleation parameters and interfacial energy was calculated through the induction time(t_(ind)) data. Homogeneous nucleation tended to occur when the supersaturation is high, whereas heterogeneous nucleation was more likely to occur when the supersaturation is low.

A New Codebook Design Scheme for Fast Beam Searching in Millimeter-Wave Communications

To overcome imperfection of exhaustive based beam searching scheme in IEEE 802.15.3c and IEEE 802.11 ad and accelerate the beam training process, combined with the fast beam searching algorithm previously proposed, this paper proposed a beam codebook design scheme for phased array to not only satisfy the fast beam searching algorithm's demand, but also make good use of the advantage of the searching algorithm. The simulation results prove that the proposed scheme not only performs well on flexibility and searching time complexity, but also has high success ratio.

Sinking of particulates ^(234)Th_(xs),~7Be and ^(210)Pb_(xs) in the Changjiang estuary,China

The time scale of transport and reaction processes in the ocean can be evaluated using natural radionuclides of different half-lives.In the present study,we evaluated the residence times of particulate reactive radionuclides 7 Be,210 Pb xs and 234 Th in the Changjiang (Yangtze River) estuary,which is a high turbidity estuary,in June,2006.The residence times of particulate 7 Be,234 Th xs and 210 Pb xs in the Changjiang estuary were calculated to be 0.7-20.4,0.18-4.1 and 0.6-89.8 d,respectively.The obtained residence times of those nuclides are comparable with those of other estuaries and bays.For 234 Th xs and 7 Be,the residence times decreased with increasing concentrations of suspended particulate matter (SPM);however,those of 210 Pb xs increased.Moreover,scavenging residence times of 234 Th and 7 Be increased from coast to offshore,while those of 210 Pb xs decreased.

The Onset of the Monsoon over the Bay of Bengal:The Year-to-Year Variations

In situ buoy observation data spanning four years(2008-2011) were used to demonstrate the year-to-year variations of the monsoon onset processes in the Bay of Bengal(BoB).A significant early(late) monsoon onset event in 2009(2010) was analyzed in detail.It is found that the year-to-year variations of monsoon onset can be attributed to either the interannual variability in the BoB SST or the irregular activities of the intra-seasonal oscillation(ISO).This finding raises concern over the potential difficulties in simulating or predicting the monsoon onset in the BoB region.This uncertainty largely comes from the unsatisfactory model behavior at the intra-seasonal time scale.

Study on Collecting Efficiency of Lube-oil Filtration Media

We made an experimental study and analysis on the relationships between filtration collecting efficiency and porosity, fiber diameter, and particles diameters for differential porosity media when fibrous media collecting lube-oil. The influencing extent of porosity, dust concentration, and velocity impacting on collecting efficiency were researched by orthogonal experimental test. The results showed that porosity had the best salience affection on collecting efficiency, and the affection of velocity and dust concentration was less. The main factors of impacting on collecting efficiency were porosity, fiber diameter, particles diameter, dust concentration, filtration time and filtration velocity. The correlation formula between collecting efficiency and porosity, aperture diameter, fiber diameter, particles diameter, the thickness of media, and filtration time was obtained. It can forecast the collecting efficiency of lube-oil filtration media and provide a guide for selecting suitable fibrous filtration media.

The Optimal Depletion of Exhaustible Resource under Different Commitment

There are few papers in the literature focusing on the issue of the optimal depletion of exhaustible resources in the framework of variable time preference. This paper attempts to analyze the pure consumption of exhaustible resource under hy- perbolic time preference, and to discuss the optimal depletion rate and the effect of the protection of the exhaustible resource under different commitment abilities. The results of model show that the case of the hyperbolic discount with the full commitment of the govemment is equivalent to the case of constant discount of the social planner problem. In that case, the optimal depletion rate and the initial consumption of exhaustible resource are the slowest. On the contrary, they are the highest and the myopic behaviors lead to excessive consumption of exhaustible resources inevitably without commitment. Otherwise, in the case of partial commit- ment, the results are between the cases of full commitment and of no commitment. Therefore, with the hyperbolic time preference, the optimal depletion rate of resource depends on the commitment ability. Higher commitment ability leads to lower effective rate of time preference, and consequently, lower depletion rate and lower initial depletion value. The improvement of commitment ability can decrease the impatience and myopia behaviors, and contribute to the protection of the exhaustible resources.

Flexible gel(FG) for gas-drainage drilling sealing material based on orthogonal design

Aiming to resolve the technical problems of lower gas concentrations and a reduced effective drainage period caused by gas-drainage borehole fracture development, a flexible gel （FG） gas-drainage borehole sealing material was developed that adapts to borehole deformation. In this study, based on orthogonal tests, the effect of the ratio of material to water, stirring time and stirring speed on the viscosity, filtration property, water retention and pumpability of the FG were studied. The results indicate that the stirring speed, ratio of material to water and stirring time in turn increased the viscosity and the ratio of material to water, stirring time and stirring speed enhanced the filtration property and water retention. The FG pumps smoothly and achieves the optimal state of high water retention, low fluid loss and low viscosity when the ratio of material to water is 1：10, the stirring speed is 800 r/min, and the stirring time is 12 min. The field test results indicate that, after using the FG, the average drainage gas concentration increases by 25.9% and 27.6g and the average negative pressure of extraction increases by 2.7 kPa and 3.5 kPa com- pared with expansive cement and polyurethane, respectively.

The Time Horizon in the Evaluation of Sustainable Development

Current methods of evaluating long term Sustainable Development seldom take into account the time period over which an evaluation is made except through simplistic economic models which heavily discount the future. If sustainable development is to be a serious issue then the impact on the future of decisions made today must be properly assessed and evaluated. This requires a new understanding of time as a key feature of the Sustainability debate and new models of how this new understanding can be brought into the evaluation process. This was at the heart of the Torino declaration signed by the University organisations of the G8, G20 and developing nations in April 2009. Time is a critical part of the sustainability debate and is seldom addressed directly. This paper will provide a possible solution based on a strong theoretical and philosophical framework of how this difficult subject can be approached and applied to sustainable urban planning. The work presented is based on a philosophical model of the cosmos which has both internal and external credibility. It forms the basis ofa PhD study and has been applied to small case studies in Italy and elsewhere. These will be presented to encourage further study into this important area within the evaluation and assessment of sustainable development.

A unified approach of PID controller design for unstable processes with time delay

This paper addresses a unified approach of the PID controller design for low as well as high order unstable processes with time delay.The design method is based on the direct synthesis(DS)approach to achieve the enhanced load disturbance rejection.To improve the servo response,a two-degree of freedom control scheme has been considered.A suitable guideline has been provided to select the desired reference model in the DS scheme.The direct synthesis controller has been approximated to the PID controller using the frequency response matching method.A consistently better performance has been obtained in comparison with the recently reported methods.

Expression and significance of cyclooxygenase-2 in human lung cancer

Objective: We aimed to examine the expression of cyclooxygenase-2 and the relationship with the pathological types, TNM stage, lymph node metastasis, the degree of differentiation, smoking and the survival. Methods: Immunohistochemical staining method was used to examine the expression of cyclooxygenase-2 of 121 cases of lung cancer and three control groups. The data were statistically analyzed. Results: Compared with the health group, cyclooxygenase-2 was over expressed in the inflammatory tissue(P = 0.036), lung adenocarcinoma(P = 0.005) and squamous carcinoma(P = 0.047). Compared with patients without lymph node metastasis, cyclooxygenase-2 was over expressed(P = 0.033) in patients with lymph node metastasis. Compared with high differentiation group, cyclooxygenase-2 was over expressed(P = 0.004) in low differentiation group. Compared with non-smokers, the expression of cyclooxygenase-2 increased in smokers(P = 0.000). The median survival time of patients that the expression of cyclooxygenase-2 were negative was 9 months(95% CI, 5.6–12.4 months). The median survival time of patients that the expression of cyclooxygenase-2 were positive was 5 months(95% CI, 3–7 months). They was statistical difference(P = 0.001). Conclusion: Overexpression of cyclooxygenase-2 is associated with pathological types, TNM stage, lymph node metastasis, degrees of differentiation, smoking and prognosis in lung cancer.

Time Dependent Gaussian Equivalent Linearization of Duffing Oscillator Using Continuous Wavelet Transform

Evolutionary response analysis of Duffing oscillator using Gaussian equivalent linearization in wavelet based time-frequency frame work is presented here. Cubic （i.e., odd type） non-linearity associated with stiffness and damping is modeled. The goal of this research is to develop the mathematical model of an equivalent linear system which is applicable for different non-stationary input processes （i.e., either summation of amplitude modulated stationary orthogonal processes or digitally simulated non-stationary processes）. The instantaneous parameters of the ELTVS （equivalent linear time varying system） are evaluated by minimizing the error between the displacements of non-linear and equivalent linear systems in wavelet domain. For this purpose, three different basis functions （i.e., Mexican Hat, Morlet and a modified form of Littlewood-Paley） are used. The unknown parameters （i.e., natural frequency and damping） of the ELTVS are optimized in stochastic least square sense. Numerical results are presented for different types of input to show the applicability and accuracy of the proposed wavelet based linearization technique.

Oxidative desulfurization performance optimization of tert- amyl hydroperoxide

The desulphurization experiment of oil-soluble oxidant tert-amyl hydroperoxide with dibenzothiophene dissolved in decalin as model-oil was researched. Characterisation on oxidation product was made, and dibenzothiophene removal rate was computed. The influence factors of the oxidative reaction regent amount and the condtions of reaction temperature and reaction time were optimized and compared. The best reaction condition was reaction temperature 90℃, reaction time 3 h, ratio of oxygen to sulfur 4：1, catalyst amount 0.12 g. Dibenzothiophene removal rate reached 97% in this reaction condition.

Effect of Storage Time and Temperature on Phenolic, Flavonoid Contents and Antioxidant Properties of Milled Rice

The objective of this study was to determine the phenolic, flavonoid contents and amioxidant properties in the milled rice cv. Khaw Dawk Mali 105 during storage for 0-7 months at different temperatures. The total phenolic content of non-stored rice was 17.02 mg/g and 7-month stored rice at 25℃ was 6.07 ＋ 0.01 mg/g while storage for 7 months at 37 ℃, the phenolic contents was 7.29±0.35 mg/g. The total flavonoid content of non-stored rice was 13.26 ± 0.01 mg/g and 7 month stored rice at 25 ℃ was 6.74±0.01 mg/g while storage for 7 months at 37℃, the flavonoid content was 6.45 ± 0.12 mg/g. The antioxidant property determined by 1, 1-diphenyl-2-picrylhydrazyl （DPPH） radical expressed in the value of EC50 （DPPH） of non-stored rice was 0.27 mg/mL and 7-month stored rice at 25℃ was 12.15 mg/mL while storage for 7 months at 37℃, the antioxidant property was 6.34 mg/mL. The antioxidant property determined by lipid peroxidation expressed in the value of EC50 （lipid peroxidation） of non-stored rice was 0.12 mg/mL and 7 month stored rice at 25℃ was 1.18 rag/mL while storage for 7-months at 37 ℃, the antioxidant property was 1.10 mg/mL. The results showed that storage time at 25℃ and 37 ℃ caused decrease of extractable phenolic and flavonoid contents and antioxidant activities of the milled rice however 7-month stored milled rice at 37 ℃ milled rice at 25 ℃.

Modeling heat transfer for phase transition during pressure assisted thawing treatment

The thawing time of ice and freezed Salomon fish during high pressure assisted thawing process was evaluated by computer simulation using a finite element and the results were compared with those under atmospheric pressure. The apparent specific heat method was adopted to treat the release of latent heat. The effects of different factors on the high pressure assisted thawing process were analyzed. The time reductions of different sample dimensions were estimated and the temperature contour of thawing at different conditions was obtained. The results showed that the temperature gap of phase transition was the main factor, which could shorten the thawing time. Moreover, a second order relationship was obtained between pressure and phase transition time.

Determination of Trihalomethanes in Water Samples Using Headspace Solid-Phase Microextraction Gas Chromatography

The chlorination process is one of the water treatment method used for the disinfection of water. The disinfection by products are trihalomethanes such as chloroform, dichloromethane, dibromochloromethane and bromoform. A headspace solid-phase microextraction method has been developed for determination oftrihalomethanes in water samples. The experimental parameters such as the stirring rate, extraction time, extraction temperature and desorption time were investigated. The linearity, detection limits and percentage recovery were evaluated. The optimum conditions were stirring rate 800 rpm/min, extraction time 6 min, extraction temperature 20 ~C, desorption time 2.5 min and desorption temperature 220 ~C. The detection limits were 0.01 ~g/L and the recoveries were in the range of 86-110 %, The proposed method was successfully applied to determination of THM4 in tap water samples. The THM4 contents were varied depending on the sample sites and the season. The total THM4 contents in cool, summer and rainy season were in the range of 27.58-41.89, 32.06-60.73 and 46.26-69.87 p.g/L, respectively. Confirmation of the detected compounds in water samples were performed by gas chromatograph-mass spectrometer. The mass spectra of the target compounds in water samples is in good agreement with trihalomethanes standard spectra.