The Sword of Damocles behind the Curtain of the Earth’s Global Warming: A Review

The “mainstream” climatology (MSC)—i.e. which includes the Intergovernmental Panel on Climate Change (IPCC) community—considers the present day massive release of greenhouse gases into the atmosphere as the main cause of the current global warming trend. The main inference from this stance is that the increase in temperature must occur after the release of greenhouse gases originating from the anthropic activities. However, no scientific evidence has been provided for this basic notion. Earth paleoclimatic records document the antecedence of temperature over CO2 levels. For the past 65 Ma, the temperature parameter has controlled the subsequent increase in CO2. This includes the three rapid aberrant shifts and extreme climate transients at 55 Ma, 34 Ma, and 23 Ma REF _Ref159913672 \r \h \* MERGEFORMAT [1]. The simple fact of their existence points to the potential for highly nonlinear responses in climate forcing. Whatever these shifts and transients are, CO2 remains a second order parameter in their evolution through time. Confronted with the past, a suitable response must therefore be given to the unresolved question of whether the CO2 trends precede the temperature trends in the current period, or not. The assertion that the current global warming is anthropogenic in origin implicitly presupposes a change of paradigm, with the consequence (the increase in CO2 levels) that occurred in Earth’s past being positioned as the cause of the warming for its present day climatic evolution. The compulsory assumption regarding the antecedence of CO2 levels over the temperature trends is associated with the haziness of the methodological framework—i.e. the paradigm—and tightens the research fields on the likely origins of global warming. The possible involvement of an “aberrant” natural event, hidden behind the massive release of greenhouse gases, has not been considered by the MSC.

Comparison of fatty liver index with noninvasive methods for steatosis detection and quantification

AIM:To compare noninvasive methods presently used for steatosis detection and quantification in nonalcoholic fatty liver disease(NAFLD).METHODS:Cross-sectional study of subjects from the general population,a subgroup from the First Israeli National Health Survey,without excessive alcohol consumption or viral hepatitis.All subjects underwent anthropometric measurements and fasting blood tests.Evaluation of liver fat was performed using four noninvasive methods:the SteatoTest;the fatty liver index(FLI);regular abdominal ultrasound(AUS);and the hepatorenal ultrasound index(HRI).Two of the noninvasive methods have been validated vs liver biopsy and were considered as the reference methods:the HRI,the ratio between the median brightness level of the liver and right kidney cortex;and the SteatoTest,a biochemical surrogate marker of liver steatosis.The FLI is calculated by an algorithm based on triglycerides,body mass index,γ-glutamyl-transpeptidase and waist circumference,that has been validated only vs AUS.FLI < 30 rules out and FLI ≥ 60 rules in fatty liver.RESULTS:Three hundred and thirty-eight volunteers met the inclusion and exclusion criteria and had valid tests.The prevalence rate of NAFLD was 31.1% according to AUS.The FLI was very strongly correlated with SteatoTest(r = 0.91,P < 0.001) and to a lesser but significant degree with HRI(r = 0.55,P < 0.001).HRI and SteatoTest were significantly correlated(r = 0.52,P < 0.001).The κ between diagnosis of fatty liver by SteatoTest(≥ S2) and by FLI(≥ 60) was 0.74,which represented good agreement.The sensitivity of FLI vs SteatoTest was 85.5%,specificity 92.6%,positive predictive value(PPV) 74.7%,and negative predictive value(NPV) 96.1%.Most subjects(84.2%) with FLI < 60 had S0 and none had S3-S4.The κ between diagnosis of fatty liver by HRI(≥ 1.5) and by FLI(≥ 60) was 0.43,which represented only moderate agreement.The sensitivity of FLI vs HRI was 56.3%,specificity 86.5%,PPV 57.0%,and NPV 86.1%.The diagnostic accuracy of FLI for steatosis > 5%,as predicted by SteatoTest,yielded an area under the receiver operating characteristic curve(AUROC) of 0.97(95% CI:0.95-0.98).The diagnostic accuracy of FLI for steatosis> 5%,as predicted by HRI,yielded an AUROC of 0.82(95% CI:0.77-0.87).The κ between diagnosis of fatty liver by AUS and by FLI(≥ 60) was 0.48 for the entire sample.However,after exclusion of all subjects with an intermediate FLI score of 30-60,the κ between diagnosis of fatty liver by AUS and by FLI either ≥ 60 or < 30 was 0.65,representing good agreement.Excluding all the subjects with an intermediate FLI score,the sensitivity of FLI was 80.3% and the specificity 87.3%.Only 8.5% of those with FLI < 30 had fatty liver on AUS,but 27.8% of those with FLI ≥ 60 had normal liver on AUS.CONCLUSION:FLI has striking agreement with SteatoTest and moderate agreements with AUS or HRI.However,if intermediate values are excluded FLI has high diagnostic value vs AUS.

Microbial Activity Indices: Sensitive Soil Quality Indicators for Trace Metal Stress

Physicochemical properties, total and DTPA （diethylenetriaminepentaacetic acid）-extractable Cu, Zn, Pb and Cd contents, microbial biomass carbon （C） content and the organic C mineralization rate of the soils in a long-term trace metal-contaminated paddy region of Guangdong, China were determined to assess the sensitivity of microbial indices to moderately metal-contaminated paddy soils. The mean contents of total Cu, Zn, Pb and Cd were 251, 250, 171, and 2.4 mg kg^-1 respectively. DTPA-extractable metals were correlated positively and significantly with total metals, CEC, and organic C （except for DTPA-extractable Cd）, while they were negatively and highly significantly correlated with pH, totall Fe and Mn. Metal stress resulted in relatively low ratios of microbial biomass C to organic C and in remarkable inhibition of the microbial metabolic quotient and C mineralization rate, which eventually led to increases in soil organic C and C/N. Moreover, microbial respiratory activity showed a stronger correlation to DTPA-extractable metals than to total metal content. Likewise, in the acid paddy soils some “linked” microbial activity indices, such as metabolic quotient and ratios of basal respiration to organic C, especially during initial incubation, were found to be more sensitive indicators of soil trace metal contamination than microbial biomass C or basal respiration alone.

Palynological Analysis of Amber-Bearing Clay from the Lower Cretaceous of Central Lebanon

An amber-bearing lignitic layer of sandy clay from the Lower Cretaceous of Central Lebanon （Mderej-Hammana）yielded a well-preserved,moderately variegated palynoflora,which origin is mixed between land plants and marine microflora.Its detailed analysis led to fulfill its inventory,to propose a paleoenvironmental reconstruction,and to draw the paleoclimate which prevailed over the region：an estuarian area under a rather humid,temperate climate;a variety of ferns grew near the shore-side and in the inward land.A tiny piece of amber containing angiospermous pollen grains of stratigraphical interest allows a precise dating.The marine microflora,poorly diversified,includes chitinous foraminifer linings and dinoflagellate cysts,among which Early Aptian guide taxa are present;their occurrence slightly narrows the stratigraphical range indicated by some palynological taxa which are related to land plants.

KINETIC FUNCTIONS IN MAGNETOHYDRODYNAMICS WITH RESISTIVITY AND HALL EFFECT

We consider a nonlinear hyperbolic system of two conservation laws which arises in ideal magnetohydrodynamics and includes second-order terms accounting for magnetic resistivity and Hall effect. We show that the initial value problem for this model may lead to solutions exhibiting complex wave structures, including undercompressive nonclassical shock waves. We investigate numerically the subtle competition that takes place between the hyperbolic, diffusive, and dispersive parts of the system. Following Abeyratne, Knowles, LeFloch, and Truskinovsky, who studied similar questions arising in fluid and solid flows, we determine the associated kinetic function which characterizes the dynamics of undereompressive shocks driven by resistivity and Hall effect. To this end, we design a new class of ＂schemes with eontroled dissipation＂, following recent work by LeFloch and Mohammadian. It is now recognized that the equivalent equation associated with a scheme provides a guideline to design schemes that capture physically relevant, nonclassical shocks. We propose a new class of schemes based on high-order entropy conservative, finite differences for the hyperbolic flux, and high-order central differences for the resistivity and Hall terms. These schemes are tested for several regimes of （co-planar or not） initial data and parameter values, and allow us to analyze the properties of nonclassical shocks and establish the existence of monotone kinetic functions in magnetohydrodynamics.

Retinoid receptor-related orphan receptor alpha： a key gene setting brain circuits

The retinoid receptor-related orphan receptor alpha（RORα） is thought to act as a constitutive activator of transcription by binding to the ROR response element（RORE） of target genes. Several mouse models in which RORα is defective have revealed the decisive roles of RORα on the development, maturation and neuroprotection of various cerebral regions including the cerebellar and somatosensory systems. We have recently shown that RORα is needed for accurate thalamic sensory system organization and somatosensory cortex development. The phenotype of various RORα deficient mice models（staggerer mutant or mouse lacking RORα in specific somatosensory regions） is, in part, reminiscent of what has been described in mice lacking thyroid hormone triiodothyronine（T3）. As in in vitro studies or in other models, our studies strongly suggest that the T3/RORα-pathway, among others, is in part responsible for the staggerer phenotype. We have indeed identified some genes that were both regulated by T3 and RORα and that are known to be implicated in the cerebellar or somatosensory system development. Moreover, several groups have shown that RORα is at the crossroad of many biological processes and pathologies, including psychiatric and degenerative disorders. In particular, defective RORα-signalling has been demonstrated in humans to be associated with the emergence of autistic-like disorders. We believe that determining the appropriate amount of RORα activity could be crucial in detecting and preventing the emergence of specific brain diseases.

A Method to Predict Amino Acids at Proximity of Beta-Sheet Axes from Protein Sequences

A general and elementary protein folding step was described in a previous article. Energy conservation during this folding step yielded an equation with remarkable solutions over the field of rational numbers. Sets of sequences optimized for folding were derived. In this work, a geometrical analysis of protein beta-sheet backbone structures allows the definition of positions of topological interest. They correspond to amino acids’ alpha carbons located on a unique axis crossing all beta-sheet’s strands or at proximity of this axis defined here. These positions of topological interest are shown to be highly correlated with the absence of sequences optimized for folding. Applications in protein structure prediction for the quality assessment of structural models are envisioned.

新发贫血对慢性心力衰竭发病率和死亡率的影响:来自COMET研究的结果

Aims: Anaemia is a common comorbidity in chronic heart failure(CHF). The predictors of new onset anaemia(NOA) and its long-term prognostic value, particularly in patients treated with beta-blockers, are not known. Methods and results: In COMET, 3029 patients with CHF in NYHA Ⅱ-IV and EF< 35%were randomized to carvedilol or metoprolol tartrate and were followed for an average of 58 months. Plasma haemoglobin(Hb) concentrations were measured at a central laboratory at randomization, at four monthly intervals for the first year and annually thereafter. According to WHO criteria, anaemia was defined when Hb measured< 13 g/dL for men and< 12 g/dL for women. We considered anaemia to be severe when Hb< 11.5 g/dL for men and< 10.5 g/dL for women. The baseline mean Hb was 14.2±1.5 g/dL(n=2996) and 15.9%of patients had anaemia(males, 16.0%; females, 15.2%). At baseline, severe anaemia was found in 3.3%of patients(males, 3.6%; females, 2.0%). During the study, all-cause mortality(RR 1.47) death or hospitalization(RR 1.28), and heart failure hospitalization(RR 1.43, all P< 0.0001) were higher in anaemic when compared with non-anaemic patients. In patients without anaemia at baseline, at the end of the study, the cumulative frequency of NOA was 28.1%in males and 27.0%in females. NOA increased over time from 14.2%at year 1 to 27.5%at year 5. Predictors of NOA were: higher age, diuretic dose, creatinine(all P< 0.0001), higher serum potassium, lower serum sodium, body mass index, and use of aldosterone antagonists, carvedilol, and digitalis(all P< 0.03). Treatment with carvedilol(vs. metoprolol tartrate) was associated with a 24%increased risk to develop NOA(P=0.0047),but not severe anaemia(P=0.18). Patients with a Hb decrease of >3 g/dL(RR 3.37, P< 0.0001) or of 2.0-3.0 g/dL(RR 1.47, P=0.011) from baseline had an increased subsequent mortality when compared with patients having Hb increases of 0-1.0 g/dL. Conclusion: In stable ambulatory CHF patients, development of NOA is frequent and can be predicted by a set of clinical variables. Decreases in Hb over time relate to future increased morbidity and mortality.

Influence of the Elastic Modulus of the Soil and Concrete Foundation on the Displacements of a Mat Foundation

In this paper, we suggest to study the behavior of a mat foundation on subsoil from the plate theory taking into account the soil-structure interaction. The objective is to highlight the soil-structure interaction particularly the influence of the rigidities of the soil and the concrete on the subgrade reaction (k) and the displacements of the mat foundation subjected to vertical loads. From plate theory and the soil-structure interaction, the general equation is reached. This equation depends more on the subgrade properties than the concrete foundation properties. Consequently, the behavior of the mat foundation is more influenced by soil properties than the concrete.

Petrology of the Volcanic Rocks from Bioko Island(“Cameroon Hot Line”)

Bioko island (3008 m a.s.l.), is composed of the alkaline basaltic lavas (basalts and hawaiites) with xenoliths. These lavas have a microlitic textureand consisted of euhedral to subhedral phenocrysts?(>1 mm) of olivine (0.83 < Mg# < 0.87) and diopside ± Ti-augite. Plagioclase (An62-67Ab35-32Or3-1) phenocrysts are present only in hawaiites. In Harker diagrams, SiO2, Al2O3, Na2O and K2O contents of the lavas increase and Fe2O3, MgO and CaO decrease with increasing differentiation from basalts to hawaiites. The compatible elements Ni, Cr and V decrease strongly in basalts and remain at low levels in hawaiites. Basaltic lavas from Bioko lavas have low Hf contents (4.2 - 9.2 ppm) and consequently higher Hf/Zr ratios (50 - 90) than those (<50) of similar lavas from other volcanoes of the Cameroon Hot Line. Such high ratios are commonly observed in alkaline basaltic lavas associated with carbonatitic and/or nephelinitic magmatism. The Sr and Nd isotopic compositions point to a slightly depleted mantle source.

New Petrological and Geochemical Data of the Nephelinitic Lavas and Geodynamic Implications of Mount Etinde (Cameroon)

Mount Etinde is a Recent (<1 Ma) strombolian-type volcano located on the southern flank of Mount Cameroon. Mount Etinde lavas are distinguished on the basis of the mineralogical compositions of their phenocrysts: olivine-pyroxene, olivine-melilite and clinopyroxene-nepheline. Some magnetite and ilmenite occur as inclusions in these early phases. Mafic mineral composition indicates that fractionation involved only limited Fe-enrichment. Oscillatory, normal and sectorial zoning in clinopyroxene relates to the differentiation and fractional crystallization of the magma. Based on the primitive mantle-normalized trace and rare earth element patterns, all nephelinites have high abundances of incompatible elements (103 < La < 281;131 < Ce < 503), with negative anomalies for high field strength element Ti and low Nb/Y (0.1 - 0.2) and Rb/Y (<0.03) ratios, suggesting derivation from a similar source. Textural characteristics and mineral chemical data, as well as whole-rock compositions, suggest that the nephelinitic lavas may have been derived from basaltic magma from a heterogeneous lithospheric mantle. Geochemical modeling of major and trace element variations indicates that the Etinde lavas could not have been produced by only fractional crystallization. Pneumatolytic reaction probably affected the pyromagmas (basaltic magma composition) and was responsible for the nephelinite rocks at lower oxygen fugacity (fO2).

PROFHMM_UNC: Introducing a Priori Knowledge for Completing Missing Values of Multidimensional Time-Series

We present a new method for estimating missing values or correcting unreliable observed values of time dependent physical fields. This method, is based on Hidden Markov Models and Self-Organizing Maps, and is named PROFHMM_UNC. PROFHMM_UNC combines the knowledge of the physical process under study provided by an already known dynamic model and the truncated time series of observations of the phenomenon. In order to generate the states of the Hidden Markov Model, Self-Organizing Maps are used to discretize the available data. We make a modification to the Viterbi algorithm that forces the algorithm to take into account a priori information on the quality of the observed data when selecting the optimum reconstruction. The validity of PROFHMM_UNC was endorsed by performing a twin experiment with the outputs of the ocean biogeochemical NEMO-PISCES model.

An Overview of the Synthesis and Gene Transfer Properties of Triblock Copolymers Poly(2-Methyl-2-Oxazoline-b-Tetrahydrofurane-b-2-Methyl-2-Oxazoline)

The synthesis of poly(2-methyl-2-oxazoline-b-tetrahydrofurane-b-2-methyl-2-oxazoline) triblock copolymer of low molar mass has been carried out. Characterization of the purified polymer by 1H and 13C NMR spectroscopies is described. These block copolymers did not give DNA containing polyplexes. The in vivo transfection properties were investigated by injection of tibialis muscles and intratracheal administration of female Swiss mice. These triblock copolymers with a molar ratio [2-methyl-2-oxazoline units]/[tetrahydrofurane units] in the 3 - 5 range gave a higher transfection efficiency than that of Lutrol or of PE6400 which are the gold standards of this transfection technique. Hydrolysis increased the performances of muscle transfection, showing the beneficial effect of the presence of positive charges, but was clearly detrimental to the transfection efficiency of pulmonary epithelium.

Floquet Theory in Electron-Helium Scattering in a Nd:YAG Laser Field

The dynamics of laser-assisted elastic collisions in helium is studied. The formalism which will be developed to describe such laser-assisted collisions, treats the laser-projectile interaction to all orders, while the electron-helium interaction is treated within the first Born-approximation. Detailed calculations are performed for the elastic scattering of 50 eV electrons by helium accompanied by the transfer of photons. The numerical results show that the good physical interpretation of relevant processes needs to consider the maximum of atomic states.

FDG-PET AS A ROUTINE SURVEILLANCE TOOL IN HEAD AND NECK CARCINOMA SIX MONTHS AFTER TREATMENT

Objective To evaluate prospectively the impact of fluorodeoxyglucose-fluorine-18 positron emission tomography (FDG-PET) in the detection of recurrence, second primary cancers, and distant metastases in head and neck squamous cell carcinoma (HNSCC) 6 months after treatment. Methods A total of 41 patients without any clinical element for recurrence, second primary cancer, or distant metastases received a whole-body FDG-PET as a routine surveillance tool 6 months after initial combined curative therapy for HNSCC. Results There were 35 negative PET results and 6 positive. One patient with abnormal FDG-PET did not have recurrent HNSCC (false positive). Five had true positive results: proven recurrence in 2 patients, second primary cancer in 2, and distant metastasis in 1. The sensitivity and specificity of FDG-PET for the diagnosis of HNSCC recurrence, second tumor, and distant metastases were 100% (5/5) and 97.2% (35/36), respectively. The positive predictive value was 83.3% (5/6). The negative predictive value was 100% (35/35). The overall accuracy was 97.6% (40/41). FDG-PET had a therapeutic impact in 5 of 41 patients (12.2%). There was no impact of FDG-PET on management in other 36 patients. Conclusion FDG-PET is useful as primary method for detecting nodal recurrence and distant metastases in HNSCC as well as second cancer in subclinical patients as it had a high effectiveness. But systematic FDG-PET performed at 6 months in patients without any clinical suspicion of local recurrence was scarcely useful.

粤北大宝山高含硫多金属矿污染的水稻土壤污染元素的多元分析

调查了粤北大宝山高含硫多金属矿长期污染的水稻田的污染状况,用主成分分析法分析了环境变量间的关系及污染物在样点的空间分布.结果表明:长期的污灌导致了被调查水田土壤中铁矿、硫铜矿和铅锌矿酸性矿泥的沉积,引起土壤酸化和硫、铜、铅和镉的积累.上述污染元素与pH及矿质元素铁、钙之间高度相关,而与锰和铬的相关性差.

Nutrition and physical activity in NAFLD:An overview of the epidemiological evidence

Nonalcoholic fatty liver disease(NAFLD)has been recognized as a major health burden.The high prevalence of NAFLD is probably due to the contemporary epidemics of obesity,unhealthy dietary pattern,and sedentary lifestyle.The efficacy and safety profile of pharmacotherapy in the treatment of NAFLD remains uncertain and obesity is strongly associated with hepatic steatosis;therefore,the first line of treatment is lifestyle modification.The usual management of NAFLD includes gradual weight reduction and increased physical activity(PA)leading to an improvement in serum liver enzymes,reduced hepatic fatty infiltration,and,in some cases,a reduced degree of hepatic inflammation and fibrosis.Nutrition has been demonstrated to be associated with NAFLD and Non-alcoholic steatohepatitis(NASH)in both animals and humans,and thus serves as a major route of prevention and treatment.However,most human studies are observational and retrospective,allowing limited inference about causal associations.Large prospective studies and clinical trials are now needed to establish a causal relationship.Based on available data,patients should optimally achieve a 5%-10%weight reduction.Setting realistic goals is essential for long-term successful lifestyle modification and more effort must be devoted to informing NAFLD patients of the health benefits of even a modest weight reduction.Furthermore,all NAFLD patients,whether obese or of normal weight,should be informed that a healthy diet has benefits beyond weight reduction.They should be advised to reduce saturated/trans fat and increase polyunsaturated fat,with special emphasize on omega-3 fatty acids.They should reduce added sugar to its minimum,try to avoid soft drinks containing sugar,including fruit juices that contain a lot of fructose,and increase their fiber intake.For the heavy meat eaters,especially those of red and processed meats,less meat and increased fish intake should be recommended.Minimizing fast food intake will also help maintain a healthy diet.PA should be integrated into behavioral therapy in NAFLD,as even small gains in PA and fitness may have significant health benefits.Potentially therapeutic dietary supplements are vitamin E and vitamin D,but both warrant further research.Unbalanced nutrition is not only strongly associated with NAFLD,but is also a risk factor that a large portion of the population is exposed to.Therefore,it is important to identify dietary patterns that will serve as modifiable risk factors for the prevention of NAFLD and its complications.

Impacts of Upper Tropospheric Cooling upon the Late Spring Drought in East Asia Simulated by a Regional Climate Model

Responses of late spring （21 April 20 May） rainfall to the upper tropospheric cooling over East Asia are investigated with a regional climate model based on Laboratoire de M6t6orologie Dynamique Zoom （LMDZ4-RCM）. A control experiment is performed with two runs driven by the mean ERA-40 data during 1958-1977 and 1981 2000, respectively. The model reproduces the major decadal-scale circulation changes in late spring over East Asia, including a cooling in the upper troposphere and an anomalous meridional cell. Accordingly, the precipitation decrease is also captured in the southeast of the upper-level cooling region. To quantify the role of the upper-level cooling in the drought mechanism, a sensitivity experiment is further conducted with the cooling imposed in the upper troposphere. It is demonstrated that the upper-level cooling can generate the anomalous meridional cell and consequently the drought to the southeast of the cooling center. Therefore, upper tropospheric cooling should have played a dominant role in the observed late spring drought over Southeast China in recent decades.

根据表观扩散系数预测梗死面积的增长:无需静脉注射对比剂评价半暗带

目的 通过对急性脑卒中病人的MR扩散加权成像（DWI）进行后处理得到表观扩散系数图（ADC图）来比较预测的和最终梗死的病变体积，证实预测的梗死面积的增长可反映因血管是否再通而处于危险状态的半暗带。方法法国立法规定基于病人医疗文件的此类研究无需通知病人并得到其同意，但病人和（或）其亲属也被告知可拒绝参加此研究。

黑色素羽毛装饰反映了鸟类的抗氧化和免疫能力吗?(英文)

鸟类信号系统研究认为,不同于类胡萝卜素,基于黑色素的羽色装饰不需要昂贵的生理代价。然而,羽毛色素细胞的黑色素沉积与抗氧化能力和免疫系统有很强的联系,而抗氧化能力和免疫系统在提高有机体适合度方面具有重要的功能。黑色素细胞的生长对氧化环境压力十分敏感;并且,黑色素本身似乎就具有抗氧化剂的功能。相应地,把抗氧化剂用于以黑色素为基础羽色发育,还是用于其它方面例如免疫调节和免疫刺激等,个体也许必须对此做出权衡。组织中的抗氧化功能大多与代谢活动有关,也就是和自由基的最高水平有关。此外,人们发现,在哺乳动物中调节黑色素沉积的激素,即α黑素细胞刺激素,在鸟类上皮组织的色素沉积中也具有同样的功能。这种进化保守的激素是免疫和炎症反应的一个重要介体。它下调前炎性细胞因子、免疫介导细胞因子和协同刺激分子,以及主要组织相容性复合体Ⅰ类分子在单核细胞的表达以及抗体的产生,而上调抑制因子白介素。黑色素在羽毛上的大量沉积,也可能反映出免疫系统在局部免疫应答的负调控能力。这些将黑色素沉积和抗氧化剂以及免疫功能联系起来的机制,表明基于黑色素的羽色信号具有一定的生理代价。