Static Research Articles

New Adaptive Clutter Rejection Based on Spectral Analysis for Ultrasound Color Doppler Imaging: Phantom and In Vivo Abdominal Study

Effective rejection of time-varying clutter originating from slowly moving vessels and surrounding tissues is important for depicting hemodynamics in ultrasound color Doppler imaging (CDI). In this paper, a new adaptive clutter rejection method based on spectral analysis (ACR-SA) is presented for suppressing nonstationary clutter. In ACR-SA, tissue and flow characteristics are analyzed by singular value decomposition and tissue acceleration of backscattered Doppler signals to determine an appropriate clutter filter from a set of clutter filters. To evaluate the ACR-SA method, 20 frames of complex baseband data were acquired by a commercial ultrasound system equipped with a research package (Accuvix V10, Samsung Medison, Seoul, Korea) using a 3.5-MHz convex array probe by introducing tissue movements to the flow phantom (Gammex 1425 A LE, Gammex, Middleton, WI, USA). In addition, 20 frames of in vivo abdominal data from five volunteers were captured. From the phantom experiment, the ACR-SA method provided 2.43 dB (p <; 0.001) and 1.09 dB ( ) improvements in flow signal-to-clutter ratio (SCR) compared to static (STA) and down-mixing (ACR-DM) methods. Similarly, it showed smaller values in fractional residual clutter area (FRCA) compared to the STA and ACR-DM methods (i.e., 2.3% versus 5.4% and 3.7%, respectively, ). The consistent improvements in SCR from the proposed ACR-SA method were obtained with the in vivo abdominal data (i.e., 4.97 dB and 3.39 dB over STA and ACR-DM, respectively). The ACR-SA method showed less than 1% FRCA values for all in vivo abdominal data. These results indicate that the proposed ACR-SA method can improve image quality in CDI by providing enhanced rejection of nonstationary clutter.

Heart rate variability during static and dynamic breath-hold dives in elite divers

The purpose of this study was to assess the differences in cardiac autonomic modulation during maximal static (SA) and dynamic (DA) underwater apneas. Arterial oxygen saturation (SpO(2)), heart rate (HR) and HR variability (SD1 from Poincaré plot and short-term fractal-like scaling exponent, α(1)) were analyzed at the immersed baseline (3 min) and initial, mid- and end-phases (each 30s) of SA and DA in nine elite breath-hold divers. DA and SA lasted 78 ± 8 and 225 ± 20s (mean ± SEM), respectively, and resulted in similar decrements in end-stage SpO(2) (78 ± 3 and 75 ± 3%, p=0.352). During DA, initial increase in HR (from 80 ± 5 to 122 ± 5 bpm, p<0.001) was followed by gradual decrease towards the baseline at mid-apnea and end-apnea phase (101 ± 6 and 80 ± 8 bpm, respectively). During SA, HR decreased at mid-apnea (from 78 ± 4 to 66 ± 3 bpm, p=0.004) but did not decrease further at end-apnea phase (66 ± 4b pm). Decreased SD1 was observed at the initial phase of DA (from 28 ± 5 to 10 ± 4 ms, p=0.005) being lower compared with SA (24 ± 4 ms, p=0.005). At the end of DA and SA, SD1 tended to increase above the baseline (62 ± 16 and 66 ± 10 ms, p=0.128 and p=0.093, respectively, p=0.602 DA vs. SA). α(1) tended to be higher at the end of DA compared with SA (1.17 ± 0.10 vs. 0.79 ± 0.10, p=0.059). We concluded that apnea blunts the effects of exercise on cardiac vagal activity at the end of DA. However, higher HR during DA compared with SA indicates larger cardiac sympathetic activity during DA, as suggested also by slightly higher α(1).

Cardiac vagal modulation during static and dynamic breathhold dives in elite divers

Marked bradycardia occurs at the end of breath‐hold dives. However, vagal modulation of heart rate (HR) during maximal static (SA) and dynamic (DA) underwater apneas is not well‐known. HR, HR variability (SD1) and arterial oxygen saturation (SpO2) were analyzed at the immersed baseline and at initial‐, mid‐ and end‐apnea (each 30 s) of maximal underwater SA and DA in nine breath‐hold divers. DA lasted 78±8 s and SA 225±20 s (mean±SEM) and resulted in similar decreases in SpO2 (78±3 and 75±3 %, p=0.352, respectively). Initially, DA increased HR from 80±5 to 122±5 bpm (p&lt;0.001), followed by decrease in HR at mid‐apnea and end‐apnea (101±6 and 80±8 bpm). During SA, HR decreased at mid‐apnea (from 78±4 to 66±3 bpm, p=0.004) but did not decrease further at end‐apnea phase. SD1 decreased at the initial phase of DA (from 28±5 to 10±4 ms, p=0.005) being lower compared with SA (24±4 ms, p=0.005). At the end of DA and SA, SD1 tended to increase above the baseline (67±16 and 66±10 ms, p=0.088 and p=0.093, respectively) and did not differ from each other (p=0.804). We concluded that apnea blunts the effects of exercise on HR variability at the end of DA when despite the higher HR. This indicates complex interplay between vagal and sympathetic responses to apnea and exercise. Supported by TEKES, Finland, Paavo Nurmi Foundation, Finland and Croatian Ministry of Science.

FlexRay Network Parameter Optimization Method for Automotive Applications

This paper describes a new FlexRay network parameter optimization (NPO) method consisting of two straightforward steps: design the lengths of the static (ST) slot and the communication cycle. In the first step, we formulate an optimal problem for designing the ST slot length. The bandwidth limitation, composed of protocol overhead and unused network resources, is considered as optimal criterion for efficient network usage. With the exploration of design space (i.e., ST slot lengths which satisfy the constraints of the FlexRay specifications), the optimal ST slot length is determined. Based on the result of the first step, the optimal communication-cycle length is designed in the next step. In this step, we proposed an algorithm for analyzing the worst case response times (WCRTs) for the ST and dynamic frames. Using this algorithm, the optimal communication-cycle length with minimum network delays is derived. The NPO method formalizes the FlexRay network configuration process in two steps for simplicity. Furthermore, the method enables the efficient usage of FlexRay bus with minimum WCRT. Finally, vehicle chassis control system based on FlexRay network is designed using the proposed NPO method. In this example system, we verified the parameter-optimization algorithm, and analysis results are confirmed.

Beam characteristics of megavoltage beams at low monitor unit settings

Beam characteristics of a linear accelerator are of great importance for intensity-modulated radiation therapy (IMRT) to ensure precise and accurate dose delivery to patients. In step-and-shoot IMRT, each beam is delivered through a series of small, segmented fields at low monitor unit (MU) settings. In this study, the beam characteristics of both static (ST) and segmental intensity-modulated (IM) beams were investigated at various dose rates for 6 and 18 MV at low MU settings. Dose linearity was investigated for both the ST and the IM beams. For the ST beams, standard 10 × 10 cm 2 fields were irradiated with MU values ranging from 1 to 100. For the IM beams, 10 × 10 cm 2 and 15 × 15 cm 2 fields were used as subfields. The normalized dose (ND)/MU was obtained. Beam flatness and symmetry for 2 and 10 MU was measured by in-plane (G–T) and cross-plane (R–L) profiles using Kodak XV films. The largest dose/MU discrepancies were observed for 1 MU. For the ST beams, the beam output decreased up to 4.5% for 1 MU at the high dose rates of 6 and 18 MV. Dose variations were less than 1% for doses above 5 MU. No significant variation was observed in the beam profiles of the ST and the IM groups. Beam flatness and symmetry were close to 3% and 2% for 6 and 18 MV, respectively. Our results showed that dose linearity and delivery errors were close to 1% for doses above 5 MU, which is considered acceptable for both 6- and 18-MV ST and IM therapy.

Functional Improvement of Pig Islet With Exocrine Encapsulation

Porcine-specific obstacles in islet isolation frequently result from the low purity or contamination with exocrine tissues. We implemented a new technique involving as capsulation of islets with excess exocrine tissue as a beneficial material to address those difficulties. Pig islets were hand-picked as high purity (HI) or low purity (LO) islets containing significant amounts of exocrine tissue. We performed static (ST) or shaking (SK) cultures of HI and LO islets. Islet function was examined after 24 hours by a glucose challenge test. Insulin secretion into the culture media was continuously measured using ELISA during a 6-day culture period. Islet function after 24 hours exhibited better maintenance under SK than ST culture as assessed by a stimulation index. The ideal islet morphology was seen in LO islets at 3 days of SK culture with typical islet shapes of a smooth surface and a spherical configuration. In contrast, typical islet morphology was not observed in HI islets under SK culture; maintenance of typical spherical appearances was difficult. Insulin secretion from LO islets under SK culture was higher than under other conditions during the 6-day period. Under SK culture conditions, exocrine-encapsulated LO islets showed enhanced islet function by condensing loose islet aggregates into firm spheroids with native exocrine tissues as a natural scaffold.

Peroxiredoxin 1 is Upregulated by Laminar Shear Stress via Nrf2 Transcription Factor

Endothelial cells (EC) exposed to oscillatory shear stress (OS) experience oxidative stress as a signature of atherosclerosis. Conversely, unidirectional laminar shear stress (LS) reduces reactive oxygen species (ROS) production and subsequent inflammatory responses. LS induces many protective genes via a shear‐sensitive antioxidant response element (ARE). We showed that the antioxidant enzyme peroxiredoxin 1 (PRX 1) is upregulated intracellularly by chronic LS, compared to OS and static (ST) culture. In addition, PRX 1‐knockdown attenuated LS‐dependent ROS reduction in EC. We hypothesize that shear‐dependent PRX 1 expression is regulated by ARE through the transcription factor nuclear factor (erythroid‐derived 2)‐related factor 2 (Nrf2). Quantitative, real‐time PCR indicated that chronic LS increased PRX 1 mRNA, compared to OS and ST. Immunoblots also showed increased PRX 1 protein expression in response to Nrf2 adenovirus infection of EC. These results indicate that shear‐dependent PRX 1 expression is regulated at the transcriptional level, and Nrf2 may play an important role in this mechanism. Through this pathway, PRX 1 acts as a mechanosensitive antioxidant implementing anti‐inflammatory and anti‐atherogenic effects of shear stress.Supported by NIH HL71014, HL75209, and HL70531 (HJ), Korean Ministry of Science &amp; Technology FPR05C2‐510 (SWK), and AHA pre‐doctoral fellowship (ALM).

Biceps brachii myoelectric and oxygenation changes during static and sinusoidal isometric exercises

Surface myoelectric signal changes occurring during sustained isometric contractions have been extensively studied with quantitative surface electromyography (sEMG) and are described by means of some sEMG global variables in time and frequency domain (such as the median power spectral frequency). Recently, the possibility of studying local muscle O 2 saturation during exercise using non-invasive methods has been enhanced thanks to the use of near-infrared spectroscopy (NIRS). The purpose of this work was to combine NIRS and sEMG techniques to analyze the relationship between modifications of sEMG parameters and the underlying metabolic status of the exercising biceps brachii muscle. This relationship was tested under different isometric contraction modalities, namely static (ST) at 20, 40, 60 and 80%MVC and sinusoidal (SIN) at 40 ± 20 and 60 ± 20%MVC. Results clearly indicated the presence of an initial fast phase of muscle O 2 desaturation followed by a slow phase, regardless of the contraction modality. Moreover, the initial rate of muscle O 2 desaturation was related to the level of force output ( R = 0.92), but it was independent on the contraction modality ( p < 0.05). Similarly, changes in sEMG parameters were related to force level (Conduction Velocity-CV vs. Force: R = 0.87; sEMG Median Frequency-MDF vs. Force: R = 0.86). The high correlation found between CV-MDF and Tissue Oxygenation Index (TOI) slope ( R = 0.73 and 0.72, respectively) suggests a strong relationship between NIRS and sEMG data. This study indicates that muscle O 2 demand during isometric contractions from low to high force levels is influenced by the type of active motor units and not from the type of isometric exercise modality.

Influence of ultrasound intensity on mass transfer in apple immersed in a sucrose solution

The influence of the ultrasonic intensity in water and dry matter transport on a system constituted by apple and sucrose solution was studied in this work. Apple slices were immersed in a 30 °Brix sucrose solution at 30 °C. Three types of treatments were carried out: static (ST), with agitation (AG) and with ultrasound application (US) at five different levels of intensity, characterized using a calorimetric method. After 45 min treatment, the water losses and the increase of dry matter were significantly higher in US samples than ST samples when the ultrasonic intensity was above 10.8 W/cm 2. At 11.5 W/cm 2, the increase of dry matter was significantly higher than in samples from AG experiments. Diffusivity of water and dry matter was identified using a model based on Fick’s law. Ultrasonic treatments (11.5 W/cm 2) supposed an increase of 117% for water diffusivity and 137% for dry matter diffusivity compared with ST experiments.

Effect of static growth and different levels of environmental oxygen on toxA and ptxR expression in the Pseudomonas aeruginosa strain PAO1

Within certain infection sites, such as the lung of cystic fibrosis patients, Pseudomonas aeruginosa grows statically under either decreased oxygen tension or anaerobic conditions, a situation that is likely to influence the production of virulence factors. The goal of this study was to determine the effect of static growth under microaerobic (decreased oxygen) and anaerobic conditions on the expression of the P. aeruginosa exotoxin A (ETA) gene toxA and its positive regulator ptxR. Using toxA-lacZ and ptxR-lacZ fusion plasmids, the level of toxA and ptxR expression was measured throughout the growth cycle of strain PAO1, which was grown in either iron-deficient or iron-sufficient medium under four different conditions: 20%-SH (aerobic, shaking), 20%-ST (aerobic, static), 10%-ST (microaerobic, static) and 0%-ST (anaerobic, static). In iron-deficient medium, toxA expression was higher under 20%-ST and 10%-ST than under 20%-SH. However, the highest level of toxA expression occurred under 0%-ST. Analysis of ETA protein using sandwich ELISA revealed that at time points between 8 and 24 h of the growth curve, PAO1 produced higher levels of ETA under 0%-ST than under 20%-SH. In iron-sufficient medium, toxA expression was significantly repressed under all conditions. Additional analyses using PAO1 strains that carry lacZ fusions with the toxA regulatory genes regA and pvdS revealed that the expression of regA and pvdS is reduced rather than increased at 0%-ST. ptxR expression under different conditions paralleled that of toxA expression, except that it was repressed by iron under 20 %-SH only. Between 6 and 24 h of growth, and under all conditions, the level of dissolved oxygen (DO) within the PAO1 cultures was sharply reduced. These results suggest that (1) the combined effect of static growth and anaerobic conditions produce a significant increase in toxA and ptxR expression in PAO1; (2) this effect appears to be unique to toxA and ptxR, since the level of regA and pvdS expression was reduced under the same conditions; (3) neither static growth nor anaerobic conditions interfere with the repression of toxA expression by iron, although static growth deregulates ptxR expression with respect to iron; and (4) the enhanced expression of toxA and ptxR is not related to the reduced levels of DO in PAO1 cultures.

Acute Effect Of Static And PNF Stretching On Hip Adductor Isometric Strength

Stretching exercises are commonly recommended as part of a routine preceding strength training, intending to avoid muscle injury and soreness or improve performance. However, the most appropriate method to conciliate these two kinds of training is still poorly understood. PURPOSE To examine the acute effect of static (STA) and PNF stretching on the dominant hip adductor isometric strength. METHODS Eighteen males (26 ± 5 yr; 83.6 ± 16.7 kg) volunteered to participate in 2 adaptation sessions and 3 randomly assigned test visits involving: 1) flexibility measures before and after STA followed by an isometric strength test (IST); 2) flexibility measures before and after PNF, followed by IST; 3) control (CON): IST with no previous stretching. Stretching exercises were passive and held for 4 sets of 30 s (STA) or 10 s blocks (contract-relax PNF). Hip adductor isometric strength was measured on an isokinetic dynamometer. Peak torque (PT) was determined on 3 different angles (45°, 30° and 15°). RESULTS PT values for CON, STA and PNF were 175.3 ± 46.8 N, 159.8 ± 48.1 N and 153.8 ± 38.9 N, respectively, at 45°; 169.1 ± 54.8 N, 151.6 ± 44.7 N and 150.7 ± 34.0 N at 30°; and 153.8 ± 47.1 N, 146.3 ± 42.5 N and 142.0 ± 35.4 N at 15°. Repeated measures ANOVA followed by LSD post hoc test showed significant differences from CON at 45° and 30°, for both STA (p=0.026 and p=0.031, respectively) and PNF (p=0.003 and p=0,018, respectively), with no differences between methods. CONCLUSIONS Relatively short duration (120 s) stretching exercises results in decreases in isometric strength. Stretching routines preceding strength training should be avoided due to the possibility of impairing strength performance.

Acute Effect Of Static And PNF Stretching On Dominant Knee Flexion And Extension Strength

Stretching exercises are commonly recommended as part of a warm-up routine preceding strength exercises. However, studies have demonstrated controversial conclusions regarding the effect of this procedure on performance. PURPOSE To investigated the acute effect of static (STA) and PNF stretching on flexion and extension strength of the dominant knee. METHODS Seventeen women (24.5 ± 6.4 yr; 58.7 ± 9.6 kg; 163.7 ± 5.8 cm; 19.3 ± 5.4 % fat mass) volunteered to participate in 2 adaptation sessions and 3 randomly assigned test visits which included: a) a sit and reach test (SR), 6 stretching exercises for quadriceps and hamstrings muscles (total 6 min session) with either STA or PNF methods, another SR, and an isokinetic strength test (IS); or b) a control condition (CON) with SR and IS only. Stretching exercises were passive and held for 30 s (STA) or 10 s blocks (contract-relax PNF). Flexion and extension strength of the dominant knee were measured at 60°.S−1 on an isokinetic dynamometer. Variables analyzed were peak torque (PT), angle of PT (aPT), set total work (STW) and average power (AP). RESULTS Repeated measures ANOVA results followed by LSD post hoc test are presented below. Decreases for STA in knee flexion and extension were 9.9% and 2.3% for PT, 11.0% and 4.1% for STW, and 13.2% and 5.4% for AP, respectively. Decreases for PNF were 11.4% and 4.8% for PT, 11.7% and 6.4% for STW, and 13.2% and 8.0% for AP, respectively. Significant differences between STA and PNF were found only in knee extension PT. CONCLUSIONS Stretching exercises performed as in the present study were able to affect strength performance significantly. If the main objective of a training session is strength gains, stretching exercises performed prior to this session may impair the ability to perform strength exercises.Table

Acute Effect Of Static And PNF Stretching On Dominant Knee Flexion And Extension Strength

Stretching exercises are commonly recommended as part of a warm-up routine preceding strength exercises. However, studies have demonstrated controversial conclusions regarding the effect of this procedure on performance. PURPOSE To investigated the acute effect of static (STA) and PNF stretching on flexion and extension strength of the dominant knee. METHODS Seventeen women (24.5 ± 6.4 yr; 58.7 ± 9.6 kg; 163.7 ± 5.8 cm; 19.3 ± 5.4 % fat mass) volunteered to participate in 2 adaptation sessions and 3 randomly assigned test visits which included: a) a sit and reach test (SR), 6 stretching exercises for quadriceps and hamstrings muscles (total 6 min session) with either STA or PNF methods, another SR, and an isokinetic strength test (IS); or b) a control condition (CON) with SR and IS only. Stretching exercises were passive and held for 30 s (STA) or 10 s blocks (contract-relax PNF). Flexion and extension strength of the dominant knee were measured at 60°.S−1 on an isokinetic dynamometer. Variables analyzed were peak torque (PT), angle of PT (aPT), set total work (STW) and average power (AP). RESULTS Repeated measures ANOVA results followed by LSD post hoc test are presented below. Decreases for STA in knee flexion and extension were 9.9% and 2.3% for PT, 11.0% and 4.1% for STW, and 13.2% and 5.4% for AP, respectively. Decreases for PNF were 11.4% and 4.8% for PT, 11.7% and 6.4% for STW, and 13.2% and 8.0% for AP, respectively. Significant differences between STA and PNF were found only in knee extension PT. CONCLUSIONS Stretching exercises performed as in the present study were able to affect strength performance significantly. If the main objective of a training session is strength gains, stretching exercises performed prior to this session may impair the ability to perform strength exercises.Table

Time of day effects on sympathoadrenal and pressor reactivity to exercise in healthy men.

To investigate the influence of time of day on sympathoadrenal and pressor reactivity during exercise, eight trained men [age, mean (SD), 24 (0.5) years; maximal oxygen uptake (VO2max), 4.7 l.min-1] performed bouts of static (ST) and dynamic (DYN) exercise at 0600-0800 hours (AM) and at 1600-1800 hours (PM). The ST protocol utilized a two-leg isometric contraction at 30% maximum voluntary contraction until failure, and was monitored by a strain gauge interfaced from a leg extension apparatus to a computer. Heart rate (fc) and blood pressure (Pa) responses were recorded at rest, after 1 and 2 min of exercise, and at failure. Epinephrine (EPI) and norepinephrine (NE) levels were recorded before exercise, and after 2 min of exercise. The DYN exercise protocol involved stationary cycling for consecutive 6-min periods at 60% and 80% VO2max. fc, Pa, EPI, and NE were recorded before exercise and at each workload. No differences were observed in preexercise or exercise fc under any condition. Preexercise Pa did not differ under any condition. The Pa response to DYN was significantly higher at 80% VO2max during PM only. Pa was significantly higher in ST-PM at 1 min, 2 min, and failure. Elevations in both systolic and diastolic Pa contributed to this difference. Preexercise EPI-ST-AM was significantly elevated vs PM, but no other preexercise data were significantly different. Absolute exercise levels were significantly higher for EPI-ST-PM vs AM only, but the percentage change from baseline was significantly (P < 0.01) higher in ST-PM for EPI (+231% PM vs +32% AM) and NE (+352% PM vs +216% AM).(ABSTRACT TRUNCATED AT 250 WORDS)

A design shell for force calculations of solenoid actuators

A customized shell in Sun Openwindow for a general purpose finite element package for electromagnetic analysis of solenoid actuators is presented. Appropriate database files are created, for a predefined actuator model, which may be used without any user intervention. Generation of batch files for analysis is greatly simplified. Finally, force calculations using the Maxwell Stress Tensor and the Virtual Work Principle are conducted automatically. The program is very user friendly and is menu-driven with several pull-down menus. INTRODUCTION When using a general purpose FE package, the finite element solution forms one of the stages in the design process, as illustrated in Figure 1. The role of FE modelling is thus to provide a field solution, as well as some integral parameters such as force, impedance, etc, for a particular set of data. Typically a large number of such solutions are required for varying selected parameters, and the user may have to repeat this time consuming process several times. At the same time calculation of forces, or other global quantities, very often involves using repeatedly some of the available post-processing commands, such as line or area integration. Many of these tasks may be automated and this paper reports on such a successful attempt which involves development of a customized shell in Sun Openwindow (CusOP) [1]. The shell has been written for a general purpose FE package OPERA-2d [2], to aid the design of electromechanical actuators. A typical actuator is demonstrated in Figure 2. The force/displacement characteristics for a particular design are shown in Figure 3. Two techniques are used for force calculation : the Virtual Work Principle (VWP) and the Maxwell Stress Tensor (MST) [3]. The Opera-2d package has several analysis options : static (ST), steady state a.c. (AC), transient (TR), velocity (VL), inclusion of lamination (PF). Thzpreand postprocessing are common for all options and different results are identified by appropriate file extensions. To run the analysis program the user has to supply Transactions on Engineering Sciences vol 3, © 1993 WIT Press, www.witpress.com, ISSN 1743-3533 40 Software Applications in Electrical Engineering additional information about convergence tolerances, number of iterations, output options, type of non-linear iteration, etc. from design syste 1

Acute toxicity of Cd in stream invertebrates in relation to pH and test design

The acute toxicity of Cd to three stream invertebrates (Baetis rhodani Pict., Leptophlebia marginata (L.) and Pisidium sp.) was tested at pH 5 and 7 simultaneously in static (ST) and flow through (FT) systems. In the static design, the animals were kept individually in small boxes containing aerated stream water. In the flow through system, the three species were kept together in circular aquaria simulating stream ecosystems with patches of gravel and recirculating aerated stream water. The nominal Cd concentrations ranged from 0 to 5 mg 1−1 during an exposure period of 120 h.

Phase Shifts of Potassium Uptake Rhythm in Lemna gibba G3 Due to Light, Dark or Temperature Pulses

Phase shifts in potassium uptake rhythm during continuous light in flow medium (FMC) and static (STC) culture of Lemna gibba G3, produced by various light and temperature pulses were examined. The phase responses were very similar to those known for a variety of circadian rhythms: A pulse of high temperature (39°C) shifted the phase in the same way as a light pulse inserted during darkness. A pulse of darkness, or of low temperature (5 or 10°C), however, caused a phase shift that was the inverse of that caused by a light pulse. A temperature pulse of definite timing erased the rhythm. Although the rhythms in the STC and FMC had essentially the same phase response, a highintensity light pulse was more effective in FMC and dark and temperature pulses in STC.