Controlling Variables Research Articles

Ewing Sarcoma of the Spine: Prognostic Variables for Survival and Local Control in Surgically Treated Patients

Introduction Primary Ewing sarcoma of the spine is a challenging tumor to treat because of a high rate of local recurrence. The optimum role of surgery in the treatment of Ewing sarcoma is not clearly defined. The objective of this study was to analyze factors relevant to survival and local control in surgically treated patients diagnosed with primary Ewing sarcoma of the spine. Materials and Methods A multi-institutional international ambispective with cross-sectional follow-up data was gathered about patients who underwent surgery for primary Ewing sarcoma of the spine. The primary outcomes assessed were 5-year survival and local recurrence. Multiple variables including the Enneking appropriateness of the surgery were evaluated for relationships to the primary outcomes. An Enneking appropriate procedure for Ewing sarcoma is an en bloc resection with negative margins. Survival and recurrence were analyzed using Kaplan–Meier curves and log-rank tests. Results A total of 59 patients diagnosed with primary Ewing sarcoma of the spine underwent surgery. Enneking appropriateness of surgery was known for 55 patients; 30 treated Enneking appropriately (EA) and 25 treated Enneking inappropriately (EI). The 5-year survival was 73% ( n = 22) for EA patients and 48% ( n = 12) for EI patients. Median survival was not achieved within 5-year postoperative for EA patients and was 2.2 years for EI patients ( p = 0.124). Local recurrence occurred in 20% ( n = 6) of patients with an EA procedure versus 48% ( n = 11) of patients with an EI procedure. The rate of local control was favorable for EA-treated patients compared with EI-treated patients ( p = 0.046). Conclusion Primary spinal Ewing sarcoma requires multidisciplinary treatment. An Enneking appropriate surgical procedure is associated with longer survival and better local control. An Enneking appropriate procedure, when feasible, should be the surgical treatment of choice for primary spinal Ewing sarcoma.

Changes in neck motion and motor control and associations with neck pain in patients with non-specific neck pain

Background: Neck pain is common in the general population with one year prevalence varying from 30% to 50%. Neck pain is the fourth leading cause of years lived with disability, which underlines the importance of research to identify effective prevention and treatment strategies based on knowledge of underlyingmechanisms of neck pain. Traditionally, physiotherapists have based their treatments of neck pain patients on functional tests and clinical findings. In the last 10 years studies show that neck pain is associated with several alterations in motor control and neck motion. Purpose: In a longitudinal study design we applied a comprehensive set of tests for motor control to investigate associations between motor control and neck pain. The aim was to investigate if motor control and neck motion changed following physiotherapy treatment and secondly, if changes in motor control were associated with reduced neck pain on an individual level. Methods: Subjects with non-specific neck pain (n= 71) participated in this observational study of neck pain patients in private physiotherapy practice. Neck flexibility, joint position error (JPE), head steadiness, trajectory movement control and postural sway were recorded at baseline before start of treatment, at 2 weeks, and 2 months. Numerical Pain Rating Scale was used tomeasure neck pain at the day of testing. To analyze within subjects effects in motor control and neck pain over time we used fixed effects linear regression analysis. Results:Neck flexibility and peak velocity increased after 2 weeks and 2 months compared to baseline. Neck pain patients improved their trajectory movement control and had less postural sway after 2 weeks and 2 months compared to baseline. Joint position error and conjunct motion did not change during the follow-up period. Changes in neck motion and motor control were largest from baseline to 2 weeks with small changes between 2 weeks and 2 months. Within individual changes were assessed with univariate regression analyses and showed that reduced neck pain was associated with twoneck motion and motor control variables; increased neck flexibility, and altered postural control. Conclusion(s): We found that only increased neck flexibility and altered postural control were associated with decreased neck pain after physiotherapy Treatment. Implications: For clinicians knowledge of the associations between neck pain and motor control on an individual level rather than group level is important. This study shows that few of the variables for motor control were associated with neck pain over a course of 2 months with treatment. While neck pain has been shown to be associated stiffening motion patterns, this study suggests that clinicians should focus treatment on interventions to increase neck flexibility and postural control since these variables were the only variables associated with neck pain reduction.

Subjective - Objective Sleep Comparisons and Discrepancies Among Clinically-Anxious and Healthy Children.

We compared subjective and objective sleep patterns and problems, and examined cross-method correspondence across parent reports, child reports, and actigraphy-derived sleep variables in clinically-anxious children and healthy controls. In a multi-site, cross-sectional study, 75 pre-adolescent children (6 to 11years; M = 8.7years; SD = 1.4; n = 39/52% female) were examined including 39 with a diagnosis of primary generalized anxiety disorder (GAD) and 36 controls recruited from university-based clinics in Houston, TX and Washington, DC. Structured interviews, validated sleep questionnaires, and 1week of actigraphy data were utilized. Despite subjective reports of significantly greater sleep problems among anxious children, actigraphy data revealed no significant differences between the groups. All parents estimated earlier bedtimes and greater total sleep duration relative to actigraphy, and all children endorsed more sleep problems than parents. With few exceptions, subjective reports exhibited low and non-significant correspondence with actigraphy-based sleep patterns and problems. Our findings suggest that high rates of sleep complaints found among children with GAD (and their parents) are not corroborated by objective sleep abnormalities, with the exception of marginally prolonged sleep onset latency compared to controls. Objective-subjective sleep discrepancies were observed in both groups but more apparent overall in the GAD group. Frequent complaints of sleep problems and daytime tiredness among anxious youth might more accurately reflect difficulties prior to the actual sleep period, cognitive-affective biases associated with sleep, and/or poor sleep quality. Findings highlight the importance of considering sleep from multiple perspectives.

Reliable State Feedback Control of T–S Fuzzy Systems With Sensor Faults

This paper is concerned with reliable state feedback control synthesis for Takagi and Sugeno (T-S) fuzzy systems with sensor multiplicative faults. By considering the influence of sensor faults on both the system states and premise variables of fuzzy controllers, a class of new convex reliable stabilization conditions are proposed for T-S fuzzy systems using the properties of fuzzy product inference engines. Furthermore, the obtained result is extended to the H <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">∞</sub> reliable control case. The resulting controllers are reliable in that they provide guaranteed asymptotic stability and H <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">∞</sub> performance when all sensors are operational, as well as when some sensor experiences failures. Different from the proposed approach, the influence of sensor faults on premise variables is not considered in the existing results; then, it might not guarantee the stability and control performance for T-S fuzzy systems with premise variables dependent on the system states. A numerical example is given to illustrate the effectiveness of the proposed method.

Consensus positive position feedback control for vibration attenuation of smart structures

This paper presents a new network-based approach for active vibration control in smart structures. In this approach, a network with known topology connects collocated actuator/sensor elements of the smart structure to one another. Each of these actuators/sensors, i.e., agent or node, is enhanced by a separate multi-mode positive position feedback (PPF) controller. The decentralized PPF controlled agents collaborate with each other in the designed network, under a certain consensus dynamics. The consensus constraint forces neighboring agents to cooperate with each other such that the disagreement between the time-domain actuation of the agents is driven to zero. The controller output of each agent is calculated using state-space variables; hence, optimal state estimators are designed first for the proposed observer-based consensus PPF control. The consensus controller is numerically investigated for a flexible smart structure, i.e., a thin aluminum beam that is clamped at its both ends. Results demonstrate that the consensus law successfully imposes synchronization between the independently controlled agents, as the disagreements between the decentralized PPF controller variables converge to zero in a short time. The new consensus PPF controller brings extra robustness to vibration suppression in smart structures, where malfunctions of an agent can be compensated for by referencing the neighboring agents’ performance. This is demonstrated in the results by comparing the new controller with former centralized PPF approach.

Is ground cover vegetation an effective biological control enhancement strategy against olive pests?

Ground cover vegetation is often added or allowed to generate to promote conservation biological control, especially in perennial crops. Nevertheless, there is inconsistent evidence of its effectiveness, with studies reporting positive, nil or negative effects on pest control. This might arise from differences between studies at the local scale (e.g. orchard management and land use history), the landscape context (e.g. presence of patches of natural or semi-natural vegetation near the focal orchard), or regional factors, particularly climate in the year of the study. Here we present the findings from a long-term regional monitoring program conducted on four pest species (Bactrocera oleae, Prays oleae, Euphyllura olivina, Saissetia oleae) in 2,528 olive groves in Andalusia (Spain) from 2006 to 2012. Generalized linear mixed effect models were used to analyze the effect of ground cover on different response variables related to pest abundance, while accounting for variability at the local, landscape and regional scales. There were small and inconsistent effects of ground cover on the abundance of pests whilst local, landscape and regional variability explained a large proportion of the variability in pest response variables. This highlights the importance of local and landscape-related variables in biological control and the potential effects that might emerge from their interaction with practices, such as groundcover vegetation, implemented to promote natural enemy activity. The study points to perennial vegetation close to the focal crop as a promising alternative strategy for conservation biological control that should receive more attention.

Peripheral chemoreceptor control of cardiovascular function at rest and during exercise in heart failure patients.

Peripheral chemoreceptor activity/sensitivity is enhanced in chronic heart failure (HF), and sensitivity is linked to greater mortality. This study aimed to determine the role of the peripheral chemoreceptor in cardiovascular control at rest and during exercise in HF patients and controls. Clinically stable HF patients (n = 11; ejection fraction: 39 ± 5%) and risk-matched controls (n = 10; ejection fraction: 65 ± 2%) performed randomized trials with or without dopamine infusion (2 μg·min(-1)·kg(-1)) at rest and during 40% maximal voluntary contraction handgrip (HG) exercise, and a resting trial of 2 min of inspired 100% oxygen. Both dopamine and hyperoxia were used to inhibit the peripheral chemoreceptor. At rest in HF patients, dopamine decreased ventilation (P = 0.02), decreased total peripheral resistance index (P = 0.003), and increased cardiac and stroke indexes (P ≤ 0.01), yet there was no effect of dopamine on these variables in controls (P ≥ 0.7). Hyperoxia lowered ventilation in HF (P = 0.01), but not in controls (P = 0.9), indicating suppression of the peripheral chemoreceptors in HF. However, no decrease of total peripheral resistance index was observed in HF. As expected, HG increased heart rate, ventilation, and brachial conductance of the nonexercising arm in controls and HF patients. During dopamine infusion, there were no changes in mean arterial pressure, heart rate, or ventilation responses to HG in either group (P ≥ 0.26); however, brachial conductance increased with dopamine in the control group (P = 0.004), but decreased in HF (P = 0.02). Our findings indicate that the peripheral chemoreceptor contributes to cardiovascular control at rest in HF patients and during exercise in risk-matched controls.

Saccadic adaptation in visually normal individuals using saccadic endpoint variability from amblyopia.

Saccadic adaptation is affected by the spatial variability of the adapting error signal. Recently, we have shown that saccadic adaptation is reduced in anisometropic amblyopia, possibly impacted by spatially imprecise saccades. Here, we tested this idea by quantifying the saccadic endpoint variability difference between people with anisometropic amblyopia and visually normal individuals. We then applied this difference to the second target step distribution during saccadic adaptation in visually normal people to test whether their performance diminished to a similar extent as participants with amblyopia. Ten visually normal adults performed a double-step adaptation task (±19°, followed by 4° back-steps) with the nondominant eye under two conditions: "consistent error," using a constant back-step; and "variable error," using a variable (σdiff) back-step determined by subtracting the saccadic endpoint variability in controls from that in anisometropic amblyopia during amblyopic/nondominant eye viewing. Percentage change in saccadic gains, percentage retention, and adaptation time constants were analyzed. Percentage change in saccadic gains decreased significantly during the variable error condition (50% ± 10%) compared to the consistent error condition (69% ± 9%; P = 0.0008). Percentage retention and time constants did not differ between conditions. The adaptation magnitude during the variable error condition was comparable to the previous percentage adaptation in people with anisometropic amblyopia during the consistent error condition with amblyopic eye viewing. Our findings indicate that adding exogenous spatial noise to the adapting step consistent with the saccadic endpoint variability difference between amblyopic and visually normal groups is sufficient to reduce saccadic adaptation in healthy individuals.

Optimization and Predictive Capability of Rsm Using Controllable Variables in Azadiracha Indica Oilseeds Extraction Process

In an attempt to optimize the process condition of oil extraction from Neem seeds, Response Surface Methodology (RSM) was explored. 17 experimental runs were generated and were carried out based on controllable variables. The RSM predicted an oil yield (OY) of 45.717% (w/w) at the following control variable condition, ET= 30.00 min, NPW = 30 g and SV= 181.896 mL. Using these controllable variable conditions, the experiment was validated in triplicate and the average OY was obtained to be 45.650 % (w/w). Analysis on physicochemical properties of the OY showed that the oil was golden yellow in colour. The specific gravity and viscosity at 25 oC was found to be0.728 and 20.65 mm2/s, respectively. The percentage moisture content on wet basis and the refractive index at 40 oC were found to be 0.001 and 1.472, respectively. The saponification value and the iodine value were obtained to be 198 mg of KOH/g of oil and 112.31 g of I2/100g oil, respectively. The acid value was obtained to be 3.82 mg of KOH/g of oil while the % FFA was computed to be 1.91. The higher heating value and the cetane number of the oil were also obtained to be 39.63 MJ/kg and 48.60 MJ/kg, respectively. Gas chromatography analysis revealed that the oil is highly unsaturated. This work therefore showed the optimization and predictive capability of RSM in extraction of Neem oils.

Age, the Number of Medicines Taken and Comorbidities are Associated with Changes of Fasting Blood Glucose Levels in Elderly Diabetics Taking Propranolol and Hydrochlorothiazide

To achieve glycemic control in patients with Diabetes, various medicines are prescribed; however, some may affect blood glucose concentration, requiring dose adjustment. Studies with small sample size, reported that propranolol and hydrochlorothiazide may change glycemic levels but this data are conflicting. The aim this study is evaluating if propranolol and hydrochlorothiazide change glycemic control in elderly hypertensive diabetics compared to diabetics without hypertension. We conducted a cross-section study and included hypertensive diabetics of both genders from 18 yrs to 90 yrs of age, using propranolol and hydrochlorothiazide (DHPH) taken orally either together or separate. The group of diabetics without hypertension was composed of patients of both genders from 18 yrs to 90 yrs of age. Clinical parameters being fasting blood glucose, postprandial glycaemia and glycated hemoglobin from the last six months was collected from medical records. The differences between groups were compared by the Student’s t-test (continuous variables) and the X2-test (categorical variables). Logistic regression analyses were used to compare the influence of variables in glycemic control in both groups. The per capita income (<0.01), age (<0.01), complexity of pharmacotherapy (<0.01), number of medicines taken (<0.01) and comorbidities (<0.01) in the DHPH group was significant. Logistic regression analyses demonstrated that the comorbidities (<0.01), number of drugs taken (<0.01) and age (<0.01), influence fasting blood glucose in the DHPH group. Fasting blood glucose levels of elderly hypertensive diabetics taking propranolol and hydrochlorothiazide are influenced by age, number of medicines taken and number comorbidities.

Выбор регулируемых величин для систем автоматического управления процессами механической обработки металлов

Выбор регулируемых величин для систем автоматического управления процессами механической обработки металлов

PENGARUH MODERASI SIZE TERHADAP HUBUNGAN ANTARA FAMILY CONTROL DENGAN NILAI DAN KINERJA PERUSAHAAN

This study investigates how family control affects the corporate values and performances.Then, We also test the effect of size moderation on relation between family control affects the corporate values and performances. The respondents are all of the corporates that listed in Jakarta Stock Exchanges (JSX) on 2004 until 2007. Purposive sampling is used to choosed data’s or samples. This study only gets 30 corporates of services from of them. Regresy Linier is used to analyzed this data’s, but before it we done classics assumption test. The result shows that variable of family control directly has not positive effect to the corporate values and performances. It is evidenced by statistic analysis with t-value -0,044 and level of significance about 0,816 for the first hypothesis and with t-value 0,156 and level of significance about 0,412 for the second hypothesis. It is not support prior research by Barontini dan Caprio (2005). The test of size moderation gets result that the corporate values and performances are effected by size of corporates. It’s evidenced by level of significance about 0.00.Keywords : Agency Theory, Family Control, Firm Value, Firm Performance.

La notoriedad de la marca como factor explicativo de la eficacia de las campañas publicitarias en televisión

The purpose of this investigation is to analyze the explanatory power of brand awareness in effectiveness of television advertising measured in terms of unaided recall. This study uses a hierarchical regression analysis in which (1) the dependent variable was advertising recall, measured in a real environment with a representative sample of television audience in Spain and (2) one of the independent variables was the results of the previous awareness of the advertised brands. The variables of control included: duration of the advertisement, position and number of insertions. Thus we have provided empirical evidence to justify the potential of brand awareness in advertising practice. These evidences show that the degree of brand awareness affects the recall of advertising, and in turn, the advertising sector on television also has a positive influence on the percentages of memory of it.

Development of a simulation-software for a hydrogen production process on a solar tower

A simulation and control model for a two-step thermo-chemical water splitting cycle using metal oxids for the generation of hydrogen with a solar tower system as heat source has been developed. The simulation and control model consists of three main parts, the simulation of the solar flux distribution on the receiver, of the temperatures in the driven reactor modules and the produced hydrogen in the metal oxide.The results of the three parts of the simulation model have been evaluated by comparing and validating them with experimental data from the Hydrosol 100kWth pilot plant at the Plataforma Solar de Almería (PSA) in Spain.With the overall model of the hydrogen production plant that was created, an evaluation of the two-step thermochemical cycle process in combination with a solar tower system was performed. The model was used to perform parametric studies for the development of the plant and the operation strategies. For this purpose, a provision in the overall model was integrated. The simulation helps to reduce the frequency of using the flux measurement system and can be used for the heliostat field control, in particular for the temperature control in the solar chemical reactor modules. Because of these promising results the overall system model is being extended to enable a use as a control model with controller for the temperature control of the two core reactions in the process.The central control variable of the process control was the operating temperatures for the hydrogen production and the regeneration of the two modules. The process control with its PI controller turned out suitable to compensate diurnal changes of solar input power as well as certain statistical fluctuation due to cloud passage. At the same time the limits of the operability and controllability of the process became clear in terms of the minimum of solar power needed and maximum acceptable gradients.With this experience an operating strategy, the basic parameters of the system in operation, especially the starting up and shutdown procedures, regular operation and the response to disturbances were selected and optimized. With this operation/control strategy such a complex system can be operated in the future on a commercial scale automatically. The obtained results can also be adapted for other solar chemical processes.

Remote Terminal Unit Developed for Distribution Automation System (DAS) Using MPLAB Software

Remote Terminal Unit (RTU) is a standalone data acquisition and control unit which monitors and controls an equipment at a remote location from the central station that utilizes Distribution Automation System (DAS). The RTU acquires information such as measured values, signal, meter readings and it transmits command or instruction, sets points, controls variables and monitors function time. In the present Distribution Automation System (DAS), the distribution field of automation allows the utilities to implement a flexible control of distribution system to enhance efficiency, reliability, and quality of electric service. The implementation of distribution automation system is highlighted based on two factors; benefit and area of distribution automation system implementation. The hardware design uses PIC16F877A microcontroller to control all the functions of RTU. The types of fault detected are undervoltage and overcurrent. The design consists of MPLAB software development using C programming and hardware assembly. RTU is also designed to communicate with the Supervisory Control and Data Acquisition (SCADA) system and resulting in RTU’s ability to detect undervoltage and overcurrent fault.

Influence of Strategic Management Process on Trans-Nzoia Teachers Sacco Performance

Strategic management is the decision process that aligns the organizations’ internal capacity with the opportunities and threats it faces in the environment and is also an approach of specifying an organization’s objectives, developing strategies to achieve objectives and allocating resources to implement the strategies. Strategic management can be seen as a combination of strategy formulation, implementation and evaluation. Trans-Nzoia Teachers Sacco has undertaken strategic management process since 2005 with the aim of positioning the Sacco in the ever changing competitive business environment. No study has been done to a certain the effectiveness of the strategic management process on any organization hence the purpose of this study was to establish the influence of strategic management process (comprising of environmental factors, strategy formulation and strategy control and monitoring) on Trans-Nzoia Teachers Sacco performance. The specific objectives of the study were to establish the influence of environment on Trans-Nzoia Teachers Sacco performance, establish the influence of strategy formulation on Trans-Nzoia Teachers Sacco performance, and establish the influence of strategy Control and monitoring on Trans-Nzoia Teachers Sacco performance. The study was based on Trans-Nzoia Teachers Sacco, the theories reviewed were profit maximizing, Competition based, resource based, survival based, contingency and system perspective theories. Descriptive research was carried out simple random sampling method was used. The target population was 3452 consisting of the board, Members and employees of Trans-Nzoia Teachers Sacco Society limited., stratified random sampling method was used to select the sample size of 44 ,. The questionnaires were used to collect data from the respondents. Stepwise multiple regressions was used to analyze the data and identify predictors of Sacco performance. The main findings of the study were that the research variables of environment, strategy formulation and strategy control and monitoring had positive effect on Sacco performance and directly influence the Sacco performance.

A New Look at the Extensive Trade Margin Effects of Trade Facilitation

We estimate the effects of trade facilitation on extensive margins of trade. Using OECD Trade Facilitation Indicators – which closely reflect the Trade Facilitation Agreement negotiated at the Bali WTO Ministerial Conference of December 2013 – we show that trade facilitation in a given exporting country is positively correlated with the number of products exported by destination and with the number of export destinations served by product. To address the issue of causality, we employ an identification strategy whereby only exports of new products, or exports to new destinations, are taken into account when computing the respective margins of trade. Our findings therefore imply a positive causal impact of trade facilitation on the country-level extensive margins of trade. The results are, to a large extent, robust to alternative definitions of country-level trade margins, to different sets of controls variables and to various estimation methods. Simulating the effect of an increase to the regional or global median values of trade facilitation, we are able to quantify the potential extensive margin gains of trade facilitation reform in different regions.

An Explanation of Local Government Debt in Spain Based on Internal Control System

The literature reflects a growing interest in the research of Public Sector debt. However, this is the first time that a variable of internal control is used to analyse interaction with the level of debt. This paper analyses the influence of the level of internal control in Spanish Local Government on indebtedness. We have obtained a sample of 1,806 Spanish municipalities. The main finding is that the level of internal control system influences the municipal debt per capita, so the higher the level of internal control, the lower the level of debt. Furthermore, we confirm previously reported results.

Alternative EPR Investment Optimizing Path &amp;amp; Modeling Analysis

Eelectric power resources security is very important for the sustainable development of power industry. However, the supply of electric power resources depends on the development of the alternative power resources industry. To develop exhaustible resources are not a long way while their quality and quantity not good for our demand. To invest on alternative electric power resources industry is the necessary choose for the sustainable development of our country. Through the intruduction of electric power resources into the production function the investment of alternative electric power resources industry are set as a controllable variable. Then, the path to achieve sustainable development by adjusting investment variables were explored and some suggestions were put forward to control investment alternative power resources industries.

Gender as predictor of social rejection: the mediating/moderating role of effortful control and parenting. [El género como predictor de rechazo social: el papel mediador / moderador del control con esfuerzo y crianza de los hijos

The aim of this work was to analyze the gender differences found in a sample of 474 spanish children aged between 6 and 8 years with respect to peer rejection using a sociometric status technique. Thus, we analyzed how temperament (Effortful Control) and parenting practices (Parental support and Discipline) were involved in this relation. To measure social rejection we used the nominations method in the classroom context, while for temperament and parenting practices, parents were given a TMCQ (Temperament in Middle Childhood Questionnaire; Simmonds and Rothbart, 2004) and the Spanish version of the PCRI (Parent-Child Relationship Inventory; Gerard, 1994). Using an statistical modeling approach, we tested various mediation/moderation models until the best one with selected variables was found to explain the relation between these variables. The results confirmed gender differences in social rejection, with boys being rejected more than girls. The model that gave the best fit was the one that placed effortful control latent variable mediating the relation between gender and social rejection and parenting practices as a latent explanatory variable of effortful control. In conclusion, differences between girls and boys in social rejection are to a large extent explained by the significantly lower scores for boys in effortful control construct and, in turn, these lowest scores are explained by negative parental practices, with low levels of support and discipline.