SDA Method Research Articles

Assessing the sectoral water-energy-emissions nexus in North China: An input–output framework combining intersectoral footprint and SDA method

Assessing the sectoral water-energy-emissions nexus in North China: An input–output framework combining intersectoral footprint and SDA method

Will falling domestic labor compensation share really be improved when global trade slowdown?

The participation of Global Value Chains (GVCs) in the world’s major economies has changed from rising to falling since 2010. Based on GVCs income, SDA method and multiple panel regression, this paper explores the cross-cycle effect, mechanism and persistence paths of GVCs participation on domestic labor compensation share in 51 economies from 2000 to 2018. The paper concludes that the overall effect of participating in GVCs on domestic labor compensation share is negative. However, forward participation in GVCs perform better than backward GVCs participation in stabilizing domestic labor compensation share. Capital-biased technological progress and availability of overseas labor are conditions under which the GVCs participation undermines domestic labor compensation share. This paper propose to seize the opportunity to increase the labor compensation share through measures and policies, such as promoting fair competition in domestic market, servitization of industrial structure and the establishment of relational value chains.

Evolution of carbon emissions in China's digital economy: An empirical analysis from an entire industry chain perspective

Accompanied by the increasing scale of the digital economy, the evolution of carbon emission analyses is becoming increasingly prominent. In this study, we constructed a digital economy input-output model and proposed a carbon emissions measurement framework from an industrial chain perspective. Based on this, we empirically calculated and analyzed the carbon emissions of China's digital economy and its evolution from 2007 to 2017. Moreover, we explored the driving factors of the evolution through a multi-layer nested SDA method. The results reveal that the (1) embodied carbon emissions of the digital economy are more significant than its direct carbon emissions, mainly due to intermediate inputs from non-digital sectors; (2) carbon emissions of China's digital economy are driven by export and investment, primarily gathering in the energy-intensive sectors of the upstream industrial chain and digital-intensive sectors of the downstream industry chain; and (3) expanding demand has led to an increase in carbon emissions from the digital economy while energy use and production processes are the leading drivers for the decrease in embodied carbon. Moreover, the role of demand expansion and energy use has weakened while the role of production processes has increased. This study offers scientific guidance for regulating the development of the digital economy and scientific carbon reduction.

Standard dilution analysis using an automatic sampler and a peristaltic pump stopping step for ICP-OES determinations

This work applies a semiautomated version of the standard dilution analysis calibration method (SDA) for the determination of Ba, Be, Cd, Co, Cr, Cu, Mn, Ni, V and Zn in several matrices (0.5 % m/v Ca, 0.6 % m/v Na, Vitamin Water, apple juice, red wine, and rum) by inductively coupled plasma optical emission spectrometry (ICP-OES). SDA utilizes only two calibration solutions: S1 is a mixture of 50% v/v sample and 50% v/v of a standard solution containing the analytes and an internal standard (IS1); S2 has a 1:1 mixture of sample and a blank solution containing a second internal standard (IS2). In the present study, S1 and S2 are mixed in the ICP-OES’s sample introduction tubing to create several calibration points on the fly. The SDA calibration process is semiautomated simply by creating an analysis sequence within the instrument’s software to move the automatic sampler from S1 to S2, while including a peristaltic pump stopping step between the two calibration tubes to prevent the formation of an air bubble. The semiautomated SDA method, which includes manual peristaltic pump stopping, provides precision corresponding to < 0.8% RSD, and LOD < 20 μg L-1 for all analytes, which is lower than values calculated for the traditional standard additions method (SA). Accuracy was evaluated by analyzing a reference material (EPA Water Pollution Standard 1) and by addition and recovery experiments (percent recoveries in the 96.3–109% range for all analytes evaluated). The SDA strategy provided comparable, and mostly superior accuracy when compared with the external standard (EC), internal standard (IS) and SA calibration methods applied to ICP-OES.

An Upgraded Data Security Based on Homomorphic Encryption and Aggregate Signature Method in Wireless Sensor Network

Wireless sensor networks (WSN) have been implemented in nearly every field of use because they offer a solution to practical problems that can also be affordably implemented. The sensor nodes have limited computing resources, weak batteries, and limited storage space. The environmental or physical data collected by these nodes is transmitted straight to the BS. The data transfer cost is raised due to the direct data transmission. In addition, the lifetime of sensor networks is shortened because of the rise in energy required for data exchange. As a result, data aggregation is utilized in WSN to lessen the burden of transmission costs and lengthen the useful life of the sensor networks. Each sensor node's transmission is encrypted with cipher text generated by the Paillier homomorphic cryptosystem. In addition, the Bilinear aggregate signature method is used to create a digital signature at each sensor node. The cluster head BS is where the aggregation takes place once the cipher text and signature have been combined. Before deciding whether to accept or reject the message, the BS checks the aggregate signature. The homomorphic cryptosystem saves power because it does not perform intermediate-level or cluster-head decryption. Data integrity, authenticity, and confidentiality are all maintained while using less power with this technology. The Intel laboratory dataset is used in the implementation. When compared to current systems, the proposed SDA method requires less time and energy to calculate.

Demand-led growth decomposition: an empirical investigation of the Brazilian slowdown in the 2010s

Abstract The empirical investigation on countries' long-term growth usually relies on growth accounting methods, which are based on a supply-led approach, where factors accumulation are the main countries' growth constraints. This approach, however, ignores the importance of effective demand in explaining the long-term dynamics. Conversely, Keynesians stress the centrality of effective demand to explain why some countries present high growth rates for prolonged periods and others do not. They account for different views on the determinants of demand growth, such as exports dynamics, income distribution and public investment. The aim of the paper is twofold. Firstly, it extends the SDA method – a method that allows us to identify sources of changes in input–output matrices – to account for endogenous consumption and import-substitution impacts, and, secondly, it applies this method to understand the Brazilian slowdown in the 2010s. Based on a Miyazawa–Leontief framework, it is possible to identify the importance of each of the demand factors in explaining countries' growth, considering both the autonomous sources of demand and their potential to spread through the economy via their multiplier effects. The application of this extension to investigate the Brazilian slowdown in the 2010s shows the importance of natural resource exports, public investment and absorption of domestic demand in different sub-periods. Based on these findings, we discuss the possibility of Brazil to restore its growth potential through specific demand stimulus, such as infrastructure investments.

Some aspects of tourism and transport in the COVID-19 pandemic time

This paper is aimed to describe the association between tourism and transport, seen in the perspective of the COVID-19 pandemic. The dual role of transport and tourism in the pandemic crisis is very special: it spreads the virus around the world and at the same time is mostly impacted by the pandemic negative consequences. The research was based mainly on the critical review and analysis of the secondary data (SDA method), such available resources as literature, statistic data and reports, actions taken by governments, international institutions and law regulations (published in 2020-2021). This approach allowed deep insight and overview of the most important issues of transport that have influenced tourism in the pandemic crisis. The final result of the study showed that for destinations highly dependent upon tourism-related revenue, the lockdown and transport suspension became a great concern and resulted in economy crisis. We acknowledge that due to the objective limitations, this paper cannot provide a comprehensive insight in tourism, transport and crisis issues. However, as this topic is a rarely discussed theme in academic texts, we hope that this paper could be found useful as it explores approaches to tourism from this new perspective. The paper ends with some reflections on sustainable development of the transport sector in the post-pandemic time, when tourism is expected to recover.

Decoupled error dynamics design for discrete-time sliding mode control in industrial servo systems under control input saturation and disturbance

This paper presents a design framework for the discrete-time Sliding mode control with Decoupled disturbance compensator and Auxiliary state (SDA) method in industrial servo applications. In particular, the discrete-time SDA method is formulated to provide an excellent tracking performance even in the presence of control input saturation and disturbance. Moreover, it preserves the separation principle of the sliding mode dynamics and the disturbance estimation error dynamics of the original discrete-time Sliding Mode Control (SMC) with Decoupled Disturbance Compensator (DDC) method. However, it can be problematic due to the unpredictable transients in the error states under control input saturation. This paper investigates the error dynamics of discrete-time SDA after a transition from a saturated region to an unsaturated region, which is called the decoupled error dynamics. The decoupled error dynamics can be designed by shaping a “hidden” sliding manifold which is activated only after the transition. Based on the analysis, a systematical design methodology for the decoupled error dynamics is proposed, which prevents the recurrence of the control input saturation and provides fast convergence of the error states. The effectiveness of the proposed design methodology is shown experimentally using an industrial linear motor system.

Regional difference and drivers in China's carbon emissions embodied in internal trade

To understand the impact of China's internal trade on China's carbon emissions, this article used the multi-regional input-output model to compare embodied carbon emissions based on production principle and consumption principle in the eight major economic regions of China. Besides, the SDA method was used to reveal the drivers of changes in CO2 emissions. The study uses data from the 2007 and 2012 multi-regional input-output tables. The result shows that domestic demand emissions are the primary source of production-based emissions in China, but the proportion of external demand emissions is increasing rapidly. According to the structural decomposition of the embodied carbon emissions, it can be seen that the carbon emissions caused by the trade in intermediate products have always been a major component of external demand emissions. Further research indicates that the rapid growth in carbon emissions from the production and consumption side of the region is mainly attributed to the expansion of the final demand scale and changes in input structure of the production department. The most critical factor that restrains the increase in carbon emissions on both principles in all regions is the reduction of emission intensity in the production sector. The conclusion of this paper has important implications for how to coordinate inter-provincial trade and regionally balanced development under open economic conditions.

Drivers of CO2 emissions from power generation in China based on modified structural decomposition analysis

Currently, over 20% of global electricity and 30% of global CO2 emissions from fuel combustion are generated in China. Understanding the driving forces of CO2 emissions from power generation is critical for both decarbonizing the power sector and achieving national carbon reduction targets. The objectives of this study were to identify critical driving forces behind changes in CO2 emissions from the power sector and to propose appropriate decarbonization pathways. First, the generation and demand structures of the power sector were introduced into a CO2 emission accounting model and decomposition analysis. Instead of traditional input–output analysis, structural decomposition analysis modified using a power transmission table was used to investigate the impacts of five driving factors of CO2 emissions from China’s power generation. The five driving factors comprised the proportion of thermal power, power generation technology, power generation structure, power demand structure and power demand, whereby the latter was divided further into nine detailed parts. Considering five regional power grids in China, the contributions of these factors were analyzed at both national and regional level. The results showed that the majority of the increase in CO2 emissions during 2007–2012 could be attributed to electricity generation (96.2%) driven by changes in power demand, which should be the key to power sector decarbonization. By contrast, 30.7% of emissions were offset by changes in the proportion of thermal power and technology, demonstrating the obvious effects of China’s policy on clean energy transition. Additionally, all power grids exhibited an increase in CO2 emissions from electricity generation, with the east and central grids accounting for 64% of the national increase. Power transmission structure had only a small impact on CO2 emissions from power generation. By using the electricity transmission table, we modified SDA to overcome the time lag issues and eliminate the reliance on IO data, and continuous annual data rather than aggregated five-yearly data can be used to capture the structural effects, thus providing more precise results for the driving forces of emission changes. Our case study shows that there is huge potential in extending the IO-based SDA method to other trade-related studies.

Evaluation of Cortez OneStep Chlamydia Rapicard™ Insta Test for the Detection of Chlamydia trachomatis in Pregnant Women at Mbare Polyclinic in Harare, Zimbabwe.

Background:Cervical chlamydia infection poses high risk of pregnancy complications and neonatal infection. Reference methods for the detection of chlamydia infection are not available for routine use in developing countries. Point-of-care (POC) tests can bridge this gap. This study evaluated Cortez Onestep Chlamydia Rapicard™ insta test for the detection of Chlamydia trachomatis in pregnant women at Mbare Polyclinic and determined the prevalence of C. trachomatis.Methods:This was a cross sectional study in 242 pregnant women aged ≥18 years attending their first ANC visit at Mbare polyclinic in Harare, Zimbabwe. Data collection form was used to obtain demographic and predisposing factors to Chlamydia infection and two endocervical swabs were collected from each patient. One specimen was examined by the POC test at the clinic and the other by SDA method in the laboratory.Results:The sensitivity, specificity, positive and negative predictive values of the rapid kit were 71.4%, 99.6%, 90.9% and 98.3% respectively. Prevalence of C. trachomitis was 5.8% by SDA method.Conclusion and Global Health Implications:The kit’s sensitivity (71.4%) and specificity (99.6%) implies that the rapid test is an important test which needs further evaluations. The prevalence of C. trichomitis of 5.8% is comparable to studies done elsewhere in Africa.

Using an improved Source Directional Apportionment method to quantify the PM2.5 source contributions from various directions in a megacity in China

The transport of particulate matter (PM) and chemical species is an essential mechanism for determining the fate of PM pollutants and their effects. To determine source transport quantitatively, an ambient PM2.5 dataset from a megacity in China was analysed using a novel method called “Source Directional Apportionment” (SDA). The SDA method is developed in this work to quantify contributions of each source category from various directions. The three steps of SDA are (1) to estimate source categories and time series of source contributions to PM with a factor analysis model, (2) to identify directions by trajectory cluster analysis and (3) to quantify source directional contributions for each source category by combining the time series of source contributions to the back trajectories in each direction. For PM2.5 in Chengdu, crustal dust, vehicular exhaust, coal combustion and secondary sulphate are all important contributors to PM; secondary nitrate and cement dust are relatively less influential. Four potential source directions were identified in Chengdu during the sampling period from 2009 to 2011. The percentages of source directional contributions from Directions 1–4 (northeast, southwest to south, southwest and west) were estimated as follows: crustal dust (7.9%, 9.1%, 6.4% and 6.2%, respectively), cement dust (1.0%, 1.2%, 1.3% and 1.1%, respectively), vehicular exhaust (6.4%, 6.0%, 5.6% and 7.0%, respectively), secondary sulphate (5.1%, 5.2%, 5.6% and 8.6%, respectively) and secondary nitrate (2.0%, 2.4%, 2.5% and 2.3%, respectively). Finally, the source directional contributions to important chemical species were quantified to determine their transport from sources to receptor.

Energy Consumption Reduction Decomposition Model Based on Input-Output Analysis and Comprehensive Evaluation

According to the input-output table and energy consolidated balance sheet of 2002 and 2007, compiled physical-value energy input-output table of six major departments and then analyzed direct energy consumption index and completely energy consumption index of Jiangsu province. Using index decomposition method and SDA method, analyzed influence of changes in technical efficiency and structure on the energy consumption intensity fluctuation respectively from the whole and each department, conducted comprehensive evaluation index to comprehensively evaluate and analyze six major departments in Jiangsu province, so as to find out the main cause of the energy consumption intensity changes in Jiangsu province, and then according to the energy consumption reduction target in the “12th Five-Year” plan, we put forward relevant countermeasures：adhere to structure, technology and management energy saving carrying out together, put the industry as the main attack direction of energy saving and encourage and support enterprises to increase investment in science and technology.

An Enhanced Method of Tracking Divot Recovery in Turfgrass

Divot recovery research has shown to have a great deal of resulting variability making it difficult to draw any solid conclusions about responses to differences among species, cultivars, or cultural practices. Standard divot analysis of the white divot (SDA) uses photos of a divot over time and digital image analysis (DIA) software to calculate percent recovery based on the number of green pixels in the photo. This method, however, neglects to take into account any nongreen pixels outside of the divoted area that result from external factors. A new method of analysis was developed using pink colored sand to fill divots and altering the macro to determine the percentage of pink pixels in the photo. Two divots were created per plot in bermudagrass [Cynodon dactylon (L.) Pers.]. One divot was backfilled with United States Golf Association spec white topdressing sand and analyzed using the SDA method. The other divot was backfilled with pink colored sand and analyzed using both the standard divot analysis of the pink divot (SDAP) method as well as the pink sand analysis (PSA) method. Each divot was also visually analyzed for percent recovery. Results indicated that the PSA method increased precision when compared with standard methods. At the time when divots were visually determined to be fully recovered, SDA and SDAP reported 60 to 70% recovery, whereas PSA reported recovery above 99%. Pink sand analysis reduced variability, as validated by a reduction in standard errors and increased R2 values, and increased the speed of analysis.

Evaluation of Self-Collected Glans and Rectal Swabs from Men Who Have Sex with Men for Detection of Chlamydia trachomatis and Neisseria gonorrhoeae by Use of Nucleic Acid Amplification Tests

Self-collected glans and rectal swab specimens from men who have sex with men (MSM) may be appropriate, convenient specimens for testing. We evaluated the use of self-collected swabs for the detection of Chlamydia trachomatis and Neisseria gonorrhoeae by a transcription-mediated amplification test (AC2; Aptima Combo 2; Gen-Probe Inc.) and a strand displacement amplification test (SDA; ProbeTec; Becton Dickinson Co.) in MSM seen at the city sexually transmitted disease clinic in San Francisco, CA. For the glans swab specimen, subjects enrolled early in the study rolled a Dacron swab across the meatus three times (method 1). A slightly more invasive procedure was performed later in the study: the subjects inserted the swab 1/4 in. into the urethra, rotated the swab, and then withdrew the swab (method 2). MSM self-collected a rectal swab specimen and also provided first-catch urine (FCU). Additional rectal swab samples were then obtained by the clinician. For the detection of C. trachomatis and N. gonorrhoeae, all swabs were evaluated by AC2 and SDA, FCU was tested by AC2, and the clinician-collected rectal swabs were cultured. A rectal true-positive (TP) result was defined as a culture-positive result for C. trachomatis or N. gonorrhoeae, two or more positive nucleic acid amplification test (NAAT) results, or a single NAAT-positive result confirmed by an alternate amplification method (the Aptima C. trachomatis or N. gonorrhoeae test). A glans TP result was defined as a positive result for FCU, positive results for both glans specimens (one tested by AC2 and one tested by SDA), or a positive result for a single glans specimen confirmed by an alternate amplification method. The prevalence rates of C. trachomatis and N. gonorrhoeae by testing of FCU were 6.8% (60/882 specimens) and 12.2% (108/882 specimens), respectively. Mixed results were obtained with the glans swab: N. gonorrhoeae detection by AC2 and SDA (method 1) had the best performance (sensitivities, >92%) with samples from a population with a higher prevalence of infection, but their performance for the detection of C. trachomatis was poor and varied by collection method (sensitivities, 56 to 68%). The prevalence rates of C. trachomatis and N. gonorrhoeae in the rectum were 7.3% (66/907 specimens) and 9.4% (83/882 specimens), respectively. The sensitivities of the tests with self-collected and clinician-collected rectal swab specimens were comparable (for C. trachomatis, 41% and 44%, respectively, by SDA and 82% and 71%, respectively, by AC2; for N. gonorrhoeae, 77% and 68%, respectively, by SDA and 84% and 78%, respectively, by AC2). AC2 and SDA were far superior to culture for the detection of C. trachomatis and N. gonorrhoeae in the rectum, with both tests detecting at least twice as many infections. While we found self-collected rectal swabs from MSM to be valid specimens for testing, the sensitivities of the tests with glans swab specimens were disappointing except for those from patients with symptomatic N. gonorrhoeae infections. Self-collected glans swab specimens may not be appropriate for the detection of C. trachomatis or for the detection of N. gonorrhoeae in low-risk or asymptomatic patients by AC2 and SDA, and we would not recommend their use on the basis of our results. Further studies are needed.

Biodegradation of Bisphenol A, Bisphenol F and Bisphenol S in Seawater

A group of compounds structurally similar to bis(4-hydroxyphenyl)propane (bisphenol A, BPA) are called bisphenols (BPs), and some of them can partially replace BPA in industrial applications. The production and consumption of BPs other than BPA, especially those of bis(4-hydroxyphenyl)methane (bisphenol F, BPF) and bis(4-hydroxyphenyl)sulfone (bisphenol S, BPS), have increased recently, leading to their detection as contaminants in the aquatic environment. The three compounds tested 100% positive for estrus response in 1936 and concerns about their health risks have been increasing. Abundant data on degradation of bisphenols (BPs) has been published, but results for biodegradation of BPs in seawater are lacking. However, several research groups have focused on this topic recently. In this study, the biodegradation behaviors of three BPs, namely BPA, BPF and BPS, in seawater were investigated using TOC Handai (TOC, potential test) and river (sea) die-away (SDA, simulation test) methods, which are both a kind of river-die-away test. The main difference between the tests is that indigenous microcosms remain in the sampled raw seawater for the SDA experiments, but they are removed through filtration and dispersed into artificial seawater for the TOC experiments. The BPs, except for BPS, were degraded using both methods. The SDA method produced better biodegradation results than the TOC method in terms of degradation time (both lag and degradation periods). Biodegradation efficiencies were measured at 75–100% using the SDA method and 13–63% using the TOC method. BPF showed better degradation efficiency than BPA, BPF was > 92% and BPA 83% depleted according to the SDA tests. BPS degradation was not observed. As a conclusion, the biodegradability of the three BPs in seawater could be ranked as BPF > BPA ≫ BPS. BPF is more biodegradable than BPA in seawater and BPS is more likely to accumulate in the aquatic environment. BPS poses a lower risk to human health and to the environment than BPA or BPF but it is not amenable to biodegradation and might be persistent and become an ecological burden. Thus other degradation methods need to be found for the removal of BPS in the environment.

男女尿検体におけるStrand displacement amplification (SDA) 法を用いた&lt;I&gt;Chlamydia trachomatis&lt;/I&gt; および&lt;I&gt;Neisseria gonorrhoeae&lt;/I&gt;の検出

Urine samples collected from 422 males and 53 females visiting a clinic in Kawasaki City who were suspected to have sexually transmitted infection were tested for the detection of Chlamydia trachomatis and Neisseria gonorrhoeae by BD ProbeTecET (SDA method). The detection rates of C. trachomatis by the SDA method and polymerase chain reaction (PCR) method (control) were as high as 98.1% for C. trachomatis, and as high as 99.4% for N. gonorrhoeae, and the concordance rate of detection of both bacterial species was high. The detection sensitivity and specificity of the SDA method were 90.6 and 99.3%, respectively for C. trachomatis and 98.7% and 100% for N. gonorrhoeae, when PCR was used as the standard method. There were no differences in these results between males and females. The number of patients showing a discrepancy of the results obtained between the SDA method and the PCR method was 9 for C. trachomatis and 1 for N. gonorrhoeae, but the results of redetermination by the SDA method tended to coincide with those of the PCR method. Urine samples tested by the SDA method were positive for N. gonorrhoeae even in patients in whom the culture of secretions from the male urethra was negative for N. gonorrhoeae. Based on these results, the BD ProbeTecET (SDA method) was confirmed to have the equivalent capability to the PCR method for the detection of C. trachomatis and N. gonorrhoeae in urine samples.

Construction and validation of a prototype microarray for efficient and high‐throughput genotyping of angiosperms

Until recently, the identification of plants relied on conventional techniques, such as morphological, anatomical and chemical profiling, that are often inefficient or unfeasible in certain situations. Extensive literature exists describing the use of polymerase chain reaction (PCR) DNA-based identification techniques, which offer a reliable platform, but their broad application is often limited by a low throughput. However, hybridization-based microarray technology represents a rapid and high-throughput tool for genotype identification at a molecular level. Using an innovative technique, a 'Subtracted Diversity Array' (SDA) of 376 features was constructed from a pooled genomic DNA library of 49 angiosperm species, from which pooled non-angiosperm genomic DNA was subtracted. Although not the first use of a subtraction technique for genotyping, the SDA method was superior in accuracy, sensitivity and efficiency, and showed high-throughput capacity and broad application. The SDA technique was validated for potential genotyping use, and the results indicated a successful subtraction of non-angiosperm DNA. Statistical analysis of the polymorphic features from the pilot study enabled the establishment of accurate phylogenetic relationships, confirming the potential use of the SDA technique for genotyping. Further, the technique substantially enriched the presence of polymorphic sequences; 68% were polymorphic when using the array to differentiate six angiosperm clades (Asterids, Rosids, Caryophyllids, Ranunculids, Monocots and Eumagnoliids). The 'proof of concept' experiments demonstrate the potential of establishing a highly informative, reliable and high-throughput microarray-based technique for novel application to sequence independent genotyping of major angiosperm clades.

A NOVEL NUMERICAL APPROACH OF COMPUTING AMERICAN OPTION

It is well acknowledged that the European options can be valued by an analytic formula, but situation is quite different for the American options. Mathematically, the Black-Scholes model for the American option pricing is a free boundary problem of partial differential equation. This model is a non-linear problem; it has no closed form solution. Although approximate solutions may be obtained by some numerical methods, but the precision and stability are hard to control since they are largely affected by the singularity at the exercise boundary near expiration date. In this paper, we propose a new numerical method, namely SDA, to solve the pricing problem of the American options. Our new method combines the advantages of the Semi-analytical Method and the Sliced-fixed Boundary Finite Difference Method while overcomes demerits of the two. Using the SDA method, we can resolve the problems resulted from the singularity near the optimal exercise boundary. Numerical experiments show that the SDA method is more accurate and more stable than other numerical methods. In this paper, we focus on the American put options, but the proposed method is also applicable to other types of options.

Autonomic response to change of posture among normal and mild-hypertensive adults: Investigation by time-dependent spectral analysis

In this study, we applied the time-dependent spectral analysis approach (SDA) to investigate the autonomic changes occurring during a transition from supine to standing position (CP), in normal and unmedicated mild hypertensive subjects. The SDA method enables an accurate follow-up of the instantaneous changes in autonomic activity, even during the unsteady phase of the transition, where sudden changes in heart rate (HR) and arterial blood pressure (ABP) are observed. We were able to quantify the vagal withdrawal (reflected in the high frequency component of the time-dependent spectrum of HR fluctuations) in the immediate response to CP and the more slowly following sympathetic increase (reflected in the low frequency component of ABP). This general pattern was observed in both groups. In addition, our results identified an altered sympathetic response to CP in mild-hypertensives, as compared to normal adults. Their basal sympathetic activity is enhanced (higher mean HR and increased low frequency fluctuations in ABP) and their response to CP is reduced, as reflected only in the LF content of ABP fluctuations, relative to normals. No difference was observed in HR fluctuations, showing that there is no parasympathetically mediated alteration of the baroreflex control of HR in mild-hypertension.