Search

This paper investigates the performance of different forecasting formulas with fractional Brownian motion based on discrete and finite samples. Existing literature presents two formulas for generating optimal forecasts when continuous records are available. One formula relies on a history over an infinite past, while the other is designed for a record limited to a finite past. In reality, only observations at discrete time points over a finite past are available. In this case, the forecasting formula, which has been widely used in the literature, is the one obtained by Gatheral et al. (Volatility is rough. Quant. Finance, 2018, 18(6), 933–949) that truncates and discretizes the formula based on continuous records over an infinite past. The present paper advocates an alternative forecasting formula, which is the conditional expectation based on finite past discrete-time observations. The findings suggest that the conditional expectation approach produces more accurate forecasts than the existing method, as demonstrated by both simulated data and actual daily realized volatility (RV) observations. Moreover, we also provide empirical evidence showing that the conditional expectation approach can lead to larger economic values than the existing method. [ABSTRACT FROM AUTHOR]

The article studies a class of state-space models where the state equation is a local-to-unity process. The parameter of interest is the persistence parameter of the latent process. The large sample theory for the least squares (LS) estimator and an instrumental variable (IV) estimator of the persistent parameter in the autoregressive (AR) representation of the model is developed under two sets of conditions. In the first set of conditions, the measurement error is independent and identically distributed, and the error term in the state equation is stationary and fractionally integrated with memory parameter d ∈ (− 0.5 , 0.5) . For both estimators, the convergence rate and the asymptotic distribution crucially depend on d. The LS estimator has a severe downward bias, which is aggravated even more by the measurement error when d ≤ 0 . The IV estimator eliminates the effects of the measurement error and reduces the bias. In the second set of conditions, the measurement error is independent but not necessarily identically distributed, and the error term in the state equation is strongly mixing. In this case, the IV estimator still leads to a smaller bias than the LS estimator. Special cases of our models and results in relation to those in the literature are discussed. [ABSTRACT FROM AUTHOR]

Altered joint loading by trauma induces joint degeneration, eventually leading to the generation of post-traumatic osteoarthritis (PTOA). Recent studies have shown that α2-macroglobulin (A2M) inhibits PTOA, induced by anterior cruciate ligament transection (ACLT), pathogenesis by regulating proinflammatory cytokines and matrix metalloproteinases. However, the application of A2M is limited due to high prices. Therefore, the aim of this study is to explore the novel preparation of A2M. The early change of A2M in synovial fluid and serum was measured by ELISA. Ultra-filtered centrifugation was performed to prepare α2-macroglobulin-rich serum (A2MRS). The bioactivity of A2M in A2MRS was detected by improved Ellis and Gollas-Galvan method. The effects of A2MRS on PTOA were observed using immunohistochemistry, safranine O staining, micro X-ray, fluorescence molecular tomography etc. The concentration of A2M in PTOA group was significantly higher than that in Sham group in synovial fluid on the third day after ACLT in rat PTOA model. On the contrary, a significant downregulation of A2M levels in PTOA group was observed compared to the Sham group in serum at the seventh day after ACLT. Secondly, A2MRS was prepared successfully, and the concentration and bioactivity of A2M in A2MRS was significantly higher than that in serum. Lastly, A2MRS not only reduced notably the production of secondary cartilage ossification, type 10 collagen and matrix metalloproteinase 13, but also increased profoundly the generation of type 2 collagen, aggrecan, and chondrocytes' number. Our results indicate that A2MRS has protective effects on PTOA. [ABSTRACT FROM AUTHOR]

This article obtains the exact distribution of the maximum likelihood estimator of structural break point in the Ornstein–Uhlenbeck process when a continuous record is available. The exact distribution is asymmetric, tri-modal, dependent on the initial condition. These three properties are also found in the finite sample distribution of the least squares (LS) estimator of structural break point in autoregressive (AR) models. Motivated by these observations, the article then develops an in-fill asymptotic theory for the LS estimator of structural break point in the AR(1) coefficient. The in-fill asymptotic distribution is also asymmetric, tri-modal, dependent on the initial condition, and delivers excellent approximations to the finite sample distribution. Unlike the long-span asymptotic theory, which depends on the underlying AR roots and hence is tailor-made but is only available in a rather limited number of cases, the in-fill asymptotic theory is continuous in the underlying roots. Monte Carlo studies show that the in-fill asymptotic theory performs better than the long-span asymptotic theory for cases where the long-span theory is available and performs very well for cases where no long-span theory is available. The article also proposes to use the highest density region to construct confidence intervals for structural break point. [ABSTRACT FROM AUTHOR]

Public managers play a critical role in making and implementing environmental policies. Pre-service training provides an important opportunity to influence the environmental attitudes of public managers. Nevertheless, we know little about this influence. This research employs a classic experiment to examine the effects of a pre-service training program that exposes trainees to ecological decline in a national training program in Taiwan. There are three major findings. First, exposure to ecological decline increases trainees' pro-environmental attitudes. Second, visual presentation modes sustain the effect. Third, trainees highly motivated for public services demonstrate greater and longer-lasting pro-environmental attitudes due to ecological exposure. These findings can be used to develop and improve environmental education programs in governments. [ABSTRACT FROM AUTHOR]

Government spending on the environment has long been explained as a reaction to ecological deterioration. Little is known about the role of political institutions and players in environmental funding decisions, which is surprising given the rapid institutionalization of environmental bureaucracies since the late 1970s. Grounded in information processing theories and employing data from Hong Kong, this research examines bureaucratic strategies for influencing environmental legislation. We find three salient bureaucratic choices in budget debates: framing environmental issues broadly to include health and technological implications; formulating rationales that emphasize (potential) performance of proposed projects; and presenting narratives of the consequences of funding decisions. These strategies are part of an evolving political narrative that reflects a broader political debate on environmental institutionalization, and the need for effective strategies to improve environmental funding in governments. Our findings contribute to understanding the bureaucratic politics of environmental funding legislation. [ABSTRACT FROM AUTHOR]

Government is the primary financer of conservation services, but conservation financing in government is rarely studied. This study makes two contributions to understanding conservation financing in government. First, it develops a framework to classify and analyse conservation funding. Applying this framework to the data from Florida county governments, this study finds that conservation funding has become more stable and secure. More resources are used for large and long-term capital projects that benefit not only the current generation but also future generations, which reflects the ultimate goal of conservation. Second, this research offers an explanation about why some governments spend more on conservation than others. The results suggest that conservation funding in government is the result of combined forces in environmental pressure of economic activities and budgetary politics. The paper concludes that government should develop a structured conservation funding strategy that includes close monitoring of environmental pressure and proper political and institutional responses to the pressure. [ABSTRACT FROM AUTHOR]

Is the public more likely to trust an ethical administration? Does ethical behavior by civil servants influence public trust? This article empirically examines the relationship between administrative ethics and public trust. A model is developed linking the ethical behaviors of public organizations to citizen trust as perceived by managers. The model is tested with data from a survey of cities in the United States. The results show that there are higher perceptions of trust in cities where there are higher perceptions of ethical behaviors. The study indicates that an effective strategy to improve trust should emphasize honest behavior by employees, encourage employee openness, and promote organizational and individual loyalty to the public interest. [ABSTRACT FROM AUTHOR]

This paper deals with the limiting behavior of non-autonomous stochastic reaction-diffusion equations without uniqueness on unbounded narrow domains. We prove the existence and upper semicontinuity of random attractors for the equations on a family of unbounded (n + 1)-dimensional narrow domains, which collapses onto an n-dimensional domain. Since the solutions are non-uniqueness, which leads to a multivalued random dynamical system with the solution operators of the equation, we will prove the existence and upper semicontinuity of attractors by multivalued random dynamical system theory. [ABSTRACT FROM AUTHOR]

Background: Radiation is a mode of treatment for many pelvic malignancies, most of which originate in the gynecologic, gastrointestinal, and genitourinary systems. However, the healthy gut is unavoidably included in the irradiation volume, resulting in undesirable results that manifest as radiation-induced diarrhea (RID), which is the most common side effect of radiation therapy and significantly affects the patients' quality of life. This study aimed to investigate the potential mechanism of diarrhea after pelvic radiotherapy in rats based on the effect of radiation on bile acid homeostasis and sodium-dependent bile acid transporter (Asbt). Methods: In this experimental study, male Sprague-Dawley rats were divided into the following groups – pelvic irradiation, cholestyramine-concurrent radiation, and control groups. The rats in the pelvic irradiation group were irradiated in the pelvic region with 2 Gy per day for five consecutive days. The total bile acid (TBA) levels in the ileum, colon, and feces were measured using automatic biochemical analyzer, and the levels of individual bile acids were evaluated by liquid chromatography-mass spectrometry/mass spectrometry (LC-MS/MS). The mRNA and protein expression of Asbt in ileum were assessed by qRT-PCR and Western blot assay. The rats in the cholestyramine-concurrent radiation group were administered with cholestyramine, a bile acid-chelating resin, and concurrent radiation for 5 days. The body weight of rats was monitored daily, and the degree of diarrhea was scored. Results: Diarrhea was observed at 2 and 3 days post-pelvic radiation. The TBA levels were significantly decreased at 4 and 5 days post-radiation in the ileum (p <.01, p <.01) and increased at 4 and 5 days post-radiation in the colon (p <.05, p <.05). The fecal excretions of TBA were significantly increased at 3, 4, and 5 days post-radiation (p <.05). The levels of individual bile acids were significantly decreased in the ileum and increased in the colon and feces, post-radiation. The mRNA and protein expression of Asbt in the ileum gradually decreased with increasing days of pelvic radiation and significantly decreased at 3 and 5 days post-radiation, respectively. Furthermore, a significant decrease in body weight was observed post-pelvic radiation, and cholestyramine administration did not reverse the weight loss. However, the incidence of RID was decreased after administration of cholestyramine. Conclusions: Bile acid malabsorption is partially responsible for RID post-pelvic radiation in rats, and the potential mechanism is related to the downregulation of the ileal Asbt. [ABSTRACT FROM AUTHOR]

Assume that there are two types of insurance contracts in an insurance company. Theith related claims are denoted by {Xij,j⩾ 1},i= 1, 2. In this paper, we investigate large deviations for the difference ∑n1(t)j = 1X1j− ∑n2(t)j = 1X2jand random difference ∑N1(t)j = 1X1j− ∑N2(t)j = 1X2j, whereni(t) are positive integer functions ast→ ∞,ni(t) → ∞,i= 1, 2.Ni(t),i= 1, 2 are counting processes for the claim number. [ABSTRACT FROM AUTHOR]

Differentiating malignant from benign ascites often leads to confusion and an inability to exclude its multitude of causes in many patients. In the present study, T lymphocyte subsets and DNA ploidy in ascitic fluid were detected by flow cytometer. There were significant differences in T lymphocyte subsets between benign and malignant ascites. For malignant ascites, the sensitivity of DNA aneuploid is 75.6%, the specificity is 79.0%, and the accuracy is 77.6%. The results demonstrate that T lymphocyte subsets determination and DNA ploidy analysis can be used in the differential diagnosis between benign and malignant ascites. [ABSTRACT FROM AUTHOR]

The Mesozoic to Cenozoic mountain uplift, exhumation, and deformation of the SW Tianshan Mountains (Kyrgyzstan and Northwest China) offer an important window to understand the intra-continental rejuvenation mechanism of the Central Asian Orogenic Belt (CAOB), as response to the far-field effects of the India-Asia collision. This article presents new observation and data for the planation surface and sedimentation and deformation features of the regional intermountain basins to rebuild the orogenic history in Mesozoic to Cenozoic. Three planation surfaces were recognized by field observation, showing that the mountain may have experienced lengthy erosion since the end Cretaceous, and a continuous planation surface may have formed at the Eocene to Oligocene. The filling sequences and deformation character revealed that the orogenic disintegrate and intermountain basin formation likely began in the end of Oligocene. Subsequently, the uniform planation surface in Western Tianshan may have begun to disintegrate, leading to the basin-and-range landform formation. Folds and nappes in the Cenozoic basins, large-scale thrusting of Palaeozoic rocks over Cenozoic sediments at the basin margin associated with the rapid mountain uplift may have occurred at the end of Early Pleistocene, suggesting a tectonic inversion. The Mesozoic-Cenozoic Tianshan uplift and deformation were likely induced by the collision/accretion along the southern margin of Eurasia. Both the northward propagation of the Parmir syntaxis to the SW Tianshan and the oblique dextral faulting of the Talas-Fergana fault have likely played an important role on the formation and deformation of the Cenozoic basins in the SW Tianshan. [ABSTRACT FROM AUTHOR]

This paper dedicates on the rotor dynamics behaviour research on the turbo-expander rotor system involving droplet impact. A stochastic model based on Beta distribution and Bernoulli distribution of droplet generation is established and the formulations of droplet impact forces are deduced, which is applied on the rotor dynamics equations of the tilting pad bearing supported turbo-expander considering the temperature gradient for a further analysis. A time domain research is carried out and a conclusion that continuously droplet impact will perturb the steady vibration of the turbo-expander rotor system is obtained. Monte Carlo method is implemented for a statistics dynamics research and the results suggests that in the design of expander impellers, in order to decrease the uncertainty brought by droplet impact, the number of channels should be as few as possible, the droplet impact should be controlled to occur uniformly, and the collision, entrainment of the primary droplets and the stripping of the liquid film on the blade should be strictly restrained. [ABSTRACT FROM AUTHOR]

The purpose of this study was to evaluate the relationship between five previously established serum osteoarthritis biomarkers and the severity of cartilage lesions in the knee. Cartilage damage (classified according to the Outerbridge scoring system) and serum concentrations of cartilage oligomeric matrix protein (COMP), collagen type II C-telopeptide (CTX-II), matrix metalloproteinase-3 (MMP-3), collagen type III N-propeptide, (PIIINP), and hyaluronic acid (HA) were determined in 79 patients who underwent knee arthroscopy or total knee replacement. HA and COMP concentrations were significantly higher in the Outerbridge score 1 and 2 groups, respectively. These results suggest that serum COMP and HA concentrations can be used to predict early cartilage lesions in the knee. [ABSTRACT FROM PUBLISHER]

Ubiquitin-proteasome pathway (UPP) is the major system for the selective degradation of cellular proteins that play key roles in cellular processes. Previous study indicated that ubiquitin-proteasome inhibitor MG-132 could inhibit growth of some carcinoma. However, anti-carcinoma mechanism of MG-132 is unclear. Our objective was to investigate mechanisms of growth inhibitory effect of MG-132 on gastric carcinoma cells. Gastric carcinoma cell SGC-7901 was treated with ubiquitin-proteasome inhibitor MG-132. Cell growth suppression was evaluated with 3-(4,5-dimethylthiazole-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) assay. DNA synthesis was evaluated by (3)H-thymidine ((3)H-TdR) incorporation. Activity of telomerase was examined by telomeric repeat amplification protocol (TRAP) PCR-ELISA. Cell cycle and apoptosis were detected by flow cytometry (FCM). DNA fragment analysis was used to confirm the presence of apoptosis. Expression of p27kip1 and survivin was detected using the western blot method. After exposed to MG-132, the growth and value of (3)H-TdR incorporation of gastric carcinoma cells were obviously inhibited. TRAP PCR-ELISA showed that light absorption of cells gradually decreased after exposed to 5 microM of MG-132 for 24, 48, 72 and 96 h (P < 0.01). The percentage of cells at G(0)/G(1) phase was increased and that at S and G(2)/M phase was decreased (P < 0.01). The ratio of apoptotic cells treated with 5 microM MG-132 for 96 h was 53.7 +/- 6.4%. Agarose electrophoresis showed marked ladders. Moreover, expression of p27kip1 of cells was increased and expression of survivin was decreased. Our results suggest that MG-132 inhibits telomerase activity, induces apoptosis and G(1) arrest which is associated with upregulated p27kip1 expression and downregulated survivin expression in gastric carcinoma cells. [ABSTRACT FROM AUTHOR]

Ubiquitin-proteasome pathway (UPP) is the major system for the selective degradation of cellular proteins that play key roles in cellular processes. Previous study indicated that ubiquitin-proteasome inhibitor MG-132 could inhibit growth of some carcinoma. However, anti-carcinoma mechanism of MG-132 is unclear. Our objective was to investigate mechanisms of growth inhibitory effect of MG-132 on gastric carcinoma cells. Gastric carcinoma cell SGC-7901 was treated with ubiquitin-proteasome inhibitor MG-132. Cell growth suppression was evaluated with 3-(4,5-dimethylthiazole-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) assay. DNA synthesis was evaluated by 3H-thymidine (3H-TdR) incorporation. Activity of telomerase was examined by telomeric repeat amplification protocol (TRAP) PCR-ELISA. Cell cycle and apoptosis were detected by flow cytometry (FCM). DNA fragment analysis was used to confirm the presence of apoptosis. Expression of p27kip1 and survivin was detected using the western blot method. After exposed to MG-132, the growth and value of 3H-TdR incorporation of gastric carcinoma cells were obviously inhibited. TRAP PCR-ELISA showed that light absorption of cells gradually decreased after exposed to 5 μ M of MG-132 for 24, 48, 72 and 96 h (P < 0.01). The percentage of cells at G0/G1 phase was increased and that at S and G2/M phase was decreased (P < 0.01). The ratio of apoptotic cells treated with 5 μ M MG-132 for 96 h was 53.7 ± 6.4%. Agarose electrophoresis showed marked ladders. Moreover, expression of p27kip1 of cells was increased and expression of survivin was decreased. Our results suggest that MG-132 inhibits telomerase activity, induces apoptosis and G1 arrest which is associated with upregulated p27kip1 expression and downregulated survivin expression in gastric carcinoma cells. [ABSTRACT FROM AUTHOR]

Previous study indicated that p27kip1 gene transfer can obviously inhibit the growth of some carcinoma cells. The purpose of this study was to investigate anticarcinoma mechanism of p27kip1. Gastric carcinoma cell strain SGC-7901 was transfected with recombinant adenovirus vector carrying human p27kip1 gene (Ad-p27kip1). Expression of survivin was detected using the western blot method and activity of telomerase was examined by telomeric repeat amplification protocol (TRAP) PCR-ELISA in gastric carcinoma cells. Our results suggest that upregulated p27kip1 can downregulate survivin expression and inhibit telomerase activity in gastric carcinoma cells. [ABSTRACT FROM AUTHOR]