Deceleration Of Rate Research Articles

Demographic Transformation and International Competitiveness of the Brazilian Economy

The 2010 Census confirmed that Brazil is experiencing a substantial demographic transformation. In 1990, the fertility rate was 2.8 per woman, but by 2010 it had fallen to 1.9, a rate well below the population replacement. Projections suggest that the Brazilian fertility rate will be among the lowest in the world before the end of this decade. Are there implications of this demographic transformation on the international competitiveness of the Brazilian economy? If yes, what is the transmission mechanism, which sectors are most affected and what can be done to mitigate its effects? This article examines these issues and shows that the demographic transformation is already affecting the international competitiveness of the economy and that these effects will be even stronger over the coming years. The transmission channel is the deceleration of the growth rate of the working-age population, and therefore the labor supply is becoming more inelastic. As a consequence, wages are becoming more sensitive to increases in the demand for labor, raising production costs. We show that, first, the tradable sector is more sensitive to the demographic transformation. Second, the labor-intensive sectors are particularly affected. Third, the commodity sector is indirectly benefited by the demographic transformation. We argue that increasing labor productivity is critical to mitigating the impacts of the demographic transformation on industrial competitiveness, and, for that reason, it should be one of the main objectives of the policies aimed at increasing competitiveness and protecting jobs.

Alteration of the Cardiac Sympathetic Innervation Is Modulated by Duration of Diabetes in Female Rats

To evaluate the sympathetic innervation of the female diabetic heart, resting heart rate and sympathetic tone were assessed in vivo, and effect of tyramine on spontaneous beating rate, norepinephrine atrial concentrations, uptake, and release were determined in vitro in streptozotocin- (STZ-) treated rats and respective controls aged 3 months to 2 years. Resting bradycardia, decreased sympathetic tone, deceleration of spontaneous beating rate, and slightly declining carrier-mediated, but preserved exocytotic norepinephrine release from the atria were found in younger diabetic rats while the reactivity of the right atria to tyramine was not affected with age and disease duration. Diabetic two-year-old animals displayed symptoms of partial spontaneous recovery including normoglycemia, increased plasma insulin concentrations, fully recovered sympathetic tone, but putative change, in releasable norepinephrine tissue stores. Our data suggested that female diabetic heart exposed to long-lasting diabetic conditions seems to be more resistant to alteration in sympathetic innervation than the male one.

Adverse Effects of Combined Spinal-Epidural Versus Traditional Epidural Analgesia During Labor

Abstract Objective To compare two neuraxial block techniques during labor for maternal and fetal effects. Methods Women in labor at term with cephalic singleton fetuses were randomized (nonblinded) to receive either labor epidural (EPI) or combined spinal–epidural (CSE) analgesia. Primary outcome was prolonged deceleration (PD) of fetal heart rate. Outcomes also included hypotension, mode of delivery, and efficacy of analgesia by visual analog pain scale (VAPS) before and after block placement. Results Randomization occurred in 127 patients: 63 received EPI, 64 received CSE. There was no difference in the rate of PD in the EPI group compared with the CSE group (3.2% vs 6.2% respectively; P = 0.43, RR 2.0; 95% CI 0.4–9.3), rate of cesarean delivery, or mean epidural duration. VAPS ratings were significantly lower in the CSE group. Conclusions There were no differences in the rate of PD or other adverse outcomes. Hypotension occurred more frequently with CSE during labor at term. The study supports both EPI and CSE during labor as safe and effective techniques for neuraxial analgesia.

Maternal salivary cortisol differs by fetal sex during the second half of pregnancy

Maternal salivary cortisol was measured at weekly intervals from 24 to 38 weeks gestation. The total sample consisted of 120 women enrolled in staggered intervals in such a way as to generate weekly measures of salivary cortisol during the latter half of pregnancy. Hierarchical linear modeling revealed the expected increase in unbound maternal cortisol during this period, with a slight deceleration in rate of increase at 33 weeks gestation. Women carrying male fetuses had higher levels of salivary cortisol initially as compared to women carrying female fetuses; at 30 weeks gestation there was cross-over such that higher maternal cortisol was observed in women carrying female fetuses beyond this time and through term. Results highlight the importance of considering fetal sex as a moderator of contemporaneous and predictive associations between maternal cortisol and prenatal or postnatal development.

Aging and photoaging

Skin aging is not a unique phenomenon but it is commonly divided into two different processes: chronological aging and photo-aging. Therefore we recognise two different phenotypes of skin aging. Chronological aging represents the structural, functional and metabolic changes in the skin that parallel the aging and degenerative changes in other body organs. Photo-aging is a consequence of oxidative damage due to overexposure to ultraviolet (UV) sunlight - both UVA and UVB (responsible for sunburn, basal and squamous cell carcinoma). Conditions of variable UV exposure may result from different latitudes, alteration of atmosphere, job (farmer towards bank employer), different behaviour to sun bathing [1]. A lot of different theories have been proposed to explain the phenomenon of aging. Many of them are interlinked. The deceleration of the mortality rate is one of the most intriguing recent findings in longevity research.

Perinatal Outcome in Pregnancies Complicated by Isolated Oligohydramnios at

Objective: To determine the perinatal outcome in pregnancies complicated by isolated oligohydramnios at term. Study Design: Comparative / Cohort study. Place and Duration of Study: This study was carried out in Unit-III at Sir Ganga Ram Hospital, Lahore from 14-05-2002 to15-06-2003. Patients and Methods: During this study 500 patients with singleton pregnancy were selected and Amniotic Fluid Index (AFI) was evaluated within 4 days of delivery in these patients with technique of Phelan et al. All selected outcome variables of these pregnancies were recorded on printed proformas. On the bases of AFI measurements patients were divided in two groups. Those who have AFI > 50 mm and < 50 mm. The significance of difference or comparison of means was measured by Chai square test (by Yats corrections). Perinatal outcomes in pregnancies with oligohydramnios were compared with those with normal amniotic fluid volume. Results: The selected outcomes showed significant variations in both groups. The statistical significance was present between advanced gestational age, presence of meconium, deceleration of fetal heart rate and chances of caesarean delivery. There were increased chances of induction of labor (41% Vs 22%) and caesarean delivery (32% Vs 23%) in oligohydramnios group. Conclusion: Oligohydramnios is associated with an increased risk of caesarean delivery for fetal distress and perinatal morbidity. Key Words: Isolated Oligohydramnios, perinatal outcome.

A patient with pregnancy-related acute abdomen after hemodialysis for over 18 years

Because pregnancy is rare in women with end-stage renal disease, dialysis patients have not been reported to present with acute abdominal symptoms related to pregnancy including ectopic pregnancy. A 41-year-old woman treated with hemodialysis for over 18 years was brought to the emergency room at our institution because of acute abdominal pain. Ultrasonography detected an abdominal fluid collection, and her anemia had worsened (hematocrit 18%). Emergency laparoscopic exploration disclosed a hemorrhagic corpus luteum of pregnancy, causing ovarian bleeding on the left. Coagulation of bleeding points was carried out. At this time, pregnancy at 7 weeks of gestation was discovered. After the procedures, hemodialysis frequency was increased to 5 times weekly, and an erythropoietin derivative was administered to maintain a hematocrit above 30%. The patient developed no hypertension. At 33 weeks of gestation, cesarean section was performed because of a decrease in amniotic fluid and frequent late deceleration of the fetal heart rate. A live baby girl weighing 1,422 g was born. The successful pregnancy reflects remarkable progress in dialysis technology. Pregnancy, then, can underlie an acute abdomen in childbearing-age women (14 - 44 years old) undergoing long-term dialysis.

Recurrent Antepartum Compression of a Single Artery Double Nuchal Cord Necessitating Emergency Cesarean Delivery

Fetuses with a single umbilical artery are considered at increased risk for chromosomal and structural abnormalities, and increased adverse perinatal outcome. A young nulliparous patient was followed with weekly nonstress testing due to well-controlled gestational diabetes, a single umbilical artery, and a double nuchal cord. At 31 weeks gestation, following the occurrence of a severe prolonged variable deceleration of the fetal heart rate the patient was hospitalized for close fetal surveillance with consideration that the deceleration may represent recurring intermittent compression of the single umbilical artery. Continuous fetal monitoring depicted recurrent severe variable decelerations of the fetal heart rate. Thirty-six hours after admission, prolonged fetal bradycardia to 60 bpm necessitated emergency cesarean delivery of a nonhypoxic nonacidotic fetus, which subsequently did well. This case suggests that fetuses with a single umbilical artery nuchal cord(s) may be at increased risk of significant umbilical cord compression.

Delay in the growth of polymer spherulites caused by superheating

Kinetics of crystal growth has considerable importance in industry, either for the influence on production time or on the mechanical properties of the resulting goods [1]. Heat transfer from a crystallizing substance to the surroundings is indispensable for the crystallization to proceed [2]. Otherwise, the temperature of the substance would increase and, according to the thermodynamics, the solid–liquid equilibrium be shifted in favour of the liquid phase. The local arrest of crystallization because of superheating at the growth front is a well-known phenomenon for metals, readily identified since it leads to characteristic dendritic morphologies [3]. The recognition of superheating at the growth front of polymer spherulites is not as obvious as for metals. Indeed, because of the slow crystallization rate of polymers relative to metals, such a phenomenon would go unnoticed under conventional isothermal crystallization since neither a variation of the circular shape of spherulites nor an appreciable deceleration of the radial growth rate can be usually produced. However, the mathematical relationship between the radius of polymer spherulites and the radial growth rate calculated under isothermal conditions may be exploited to derive the theoretical change of the dimension of a spherulite growing under nonisothermal conditions in the absence of superheating. Comparing this value to the experimental datum, it is possible to draw information on the occurrence of superheating phenomena. In this work a method is shown to demonstrate the deceleration of polymer spherulites as a consequence of superheating. The method consists in measuring the increase of the radius of spherulites while the external temperature is increased in the range where crystallization occurs. Despite the invariability of the exterior spherulitic structure on the optical scale, the deceleration of the crystal growth during heating may be proved on the basis of the comparison between the theoretically predictable enhancement of spherulite size and the experimental value. Isotactic polypropylene with a small amount (2.4 wt%) of ethylenic units randomly distributed along the chain has been used in the present investigation. The product (E/P), having weight-average molecular weight Mw = 216 000, was kindly supplied by Montell Polyolefins Company (Ferrara, Italy) and used, instead of isotactic polypropylene homopolymer, because of its wider crystallization temperature range [4]. The following experimental procedures were adopted. For optical observations during crystallization, a small amount of E/P was squashed between two glass slides to give tens of micrometers thick film. Specimens were then inserted in a Linkam THMS 600 hot stage programmed by a TMS91 unit. In isothermal crystallization, specimens were kept at 473 K for 600 s in order to destroy any previous trace of crystallinity and then the temperature rapidly decreased (with a scan rate of −0.5 K/s) to the selected crystallization temperature in the range 393–413 K. The hot stage device was maintained at a constant temperature until primary crystallization was completed. In nonisothermal procedures, the temperature was kept at 473 K for 600 s, and then rapidly decreased to 393 K, allowing nucleation to that temperature, and finally increased at 0.0833 K/s during crystallization up to 413 K. A. Zeiss polarizing microscope equipped with a JVS TK-1085E video camera was used for images acquisition. Pictures were taken at appropriate instants of time and the radius of spherulites measured with Image-Pro Plus software in order to estimate the linear growth rate. A graduate grid was used for length calibration. The radial growth rate G of spherulites is achievable by measuring the radius r of spherulites as a function of time t . The slopes of the isothermal lines resulting in r–t plots provided the values of G as function of temperature. Values of G in the explored temperature range are reported in Table I; the equation between G and T may be obtained by means of the least square method. This procedure, applied to E/P crystallization in the range 393–413 K, resulted in the following equation:

Atomic force microscopy of fatigue crack growth behavior in the low K region

Fatigue crack growth tests were performed under constant amplitude loading in the low K region using a grain-oriented 3% silicon iron, which had two operative preferential slip systems against the direction perpendicular to the loading axis. Growth behavior of fatigue crack and slip deformation near the crack tip were observed in detail by means of an atomic force microscope (AFM). It was found that the inclined fatigue crack grew along one preferential slip plane, since one of the two slip systems operated predominantly in the low K region where crack driving force was relatively low. The crack growth along one slip plane was then followed by crack deflection or kinking. The microscopic length of crack extension was measured by successive AFM observations as well as the slip deformation at the crack tip by an image processing technique. It was found that the crack growth decelerated and the amount of slip deformation in front of the crack tip became small just before crack deflection took place. It could be concluded that the piled up dislocations were cyclically introduced in front of the crack tip as a consequence of crack growth along one slip plane, which brought about both the reduction of slip deformation and the deceleration of growth rate. Then the other slip system, the direction of which is different from that of the constrained slip, would be activated and resulted in crack deflection or kinking. Fatigue crack growth model in the low K region was successfully proposed in view of AFM microscopy.

Paradoxical autonomic modulation of atrioventricular nodal conduction during heart rate turbulence.

Heart rate turbulence (HRT) represents a biphasic chronotropic response of sinus rhythm to a single ventricular premature beat (VPB). It consists of early acceleration and late deceleration of heart rate and is predominantly mediated by the autonomic nervous system. The aim of this study was to investigate if autonomic perturbations after a VPB exert a significant effect on AV conduction. Both surface ECG and the high right atrial electrogram were recorded at a sampling frequency of 1000 Hz in 26 patients (24 men, mean age 49 +/- 12 years) referred for electrophysiological evaluation. The stimulation protocol consisted of series of single ventricular extrastimuli delivered from the right ventricular apex at decreasing coupling intervals. A biphasic profile of AV intervals after a single VPB was observed. The response of AV conduction to a VPB was approximately 25 times and 15 times weaker in the early and late phase, respectively, than that of R-R intervals. Thus, AV interval dynamics significantly preceded the change in R-R intervals, which is in conflict with the near to zero phase of transfer function between R-R and AV intervals described in previous studies. A significant AV turbulence was observed consisting of early shortening and later prolongation of AV intervals after VPB. Its magnitude was much smaller than that of HRT. Dynamics of AV delay has little impact on the accuracy of HRT assessment from surface ECG. The significant temporal dissociation of R-R and AV interval dynamics after a VPB remains unexplained.

Measurement of Kodaikanal white-light images – VI. Variation of Rotation Rate with Age of Sunspot Groups

We find from an analysis of the Kodaikanal sunspot group data that the rotation rates of spot groups increase with their age when the rotation rates are computed after sorting the spot groups life-span-wise. We confirm these findings from an analysis of the Mt. Wilson sunspot data set too. We show that this trend is in good agreement with the internal rotation profiles from helioseismology (GONG) observations and is also consistent with the concept that the footpoints of the magnetic loops of spot groups are initially anchored in the deeper layers in the solar interior and rise to shallower layers as the spots age, and that the spots reflect the rotation rates at the respective depths at which their footpoints are temporally located. We project the `first-day rotation rates' and the `daily rotation rates' of spot groups on the rotation profiles from the GONG observations and derive the initial anchoring depths of the footpoints of the magnetic loops of the spot groups and their rates of rise as the spot groups age. Our results of the rotation rates are in antithesis to the results reported by investigators from the Greenwich spot group data that show a deceleration in rotation rates as the spot groups age which are also inconsistent with the rotation profiles from helioseismology observations.

Mechanism of Upper Temperature Limits in a Wave of Filtration Combustion of Gases

A physical mechanism is established, responsible for the experimentally observed strong deceleration of the growth rate of the maximum skeleton temperature in a wave of filtration combustion of gases with increasing flow rate. The maximum temperatures of the gas and skeleton become commensurable, and the length of the thermal‐relaxation zone becomes much shorter. A classification of regimes based on the temperature‐heterogeneity criterion ϕ1 is proposed. Explicit analytical solutions are obtained for the wave for ϕ1≪1 and ϕ1→1. A correction to reverse reactions in combustion products is considered. The effect of composition on wave behavior is studied by means of numerical calculations with a detailed kinetic scheme. The activation energy for ultrarich and ultralean methane–air mixtures is evaluated. It is concluded that the limiting efficiency of the heat‐recuperation cycle in the wave is reached as ϕ1→1; methods for maximizing the efficiency are suggested.

Chemical modification of lipases with various hydrophobic groups improves their enantioselectivity in hydrolytic reactions.

Semi-purified lipases from Candida rugosa, Pseudomonas cepacia and Alcaligenes sp. were chemically modified with a wide range of hydrophobic groups such as benzyloxycarbonyl, p-nitrobenzyloxycarbonyl, p-methoxybenzyloxycarbonyl, t-butoxycarbonyl, lauroyl and acetyl moieties. The Candida rugosa lipase MY modified with the benzyloxycarbonyl group (modification ratio = 84%) brought about a 15-fold increase in enantioselectivity (E value) towards the hydrolysis of racemic butyl 2-(4-ethylphenoxy)propionate in an aqueous buffer solution, although the enzymatic activity was decreased. The origin of the enantioselectivity enhancement by chemical modification of the lipase is attributed to a significant deceleration in the initial reaction rate for the incorrectly binding enantiomer.

Mechanisms involved in heart rate turbulence.

Proper understanding of the mechanisms involved in heart rate turbulence (HRT) may offer an explanation of why it is such a potent postinfarction risk stratifier. This article reviews the physiological background of ventriculophasic sinus arrhythmia-a phenomenon which shares some underlying physiological features with HRT including cardiac autonomic regulation. It is now believed that HRT is principally triggered by a transient loss of vagal efferent activity in response to the missed baroreflex afferent input due to ventricular premature beat-induced haemodynamically inefficient ventricular contraction. Studies are summarized which support more or less directly this hypothesis. The physiology of early acceleration and late deceleration of heart rate after a ventricular premature beat is discussed. Qualitatively different but otherwise quantitatively uniform postectopic dynamics of systolic blood pressure after ventricular premature beats is demonstrated in subjects with normal and abnormal left ventricular function. It is concluded that the slope of late deceleration of heart rate after ventricular premature beats can serve as a reasonable surrogate for baroreflex sensitivity.

Investigation of initiation and growth behavior of short fatigue cracks emanating from a single edge notch specimen using in-situ SEM

In-situ scanning electron microscope fatigue observations on initiation and propagation behavior of short fatigue cracks emanating from notch root of specimens were conducted for a low strength aluminum alloy. It was observed that short fatigue crack initiation was a process of acummulative slipping of surface grains near notch root and occurrence of multiple microcracks. The results also show that the early stage propagation of short fatigue crack was a process of the competition of multiple micro-cracks: one of them became a dominant propagating crack while most of them became dormant (i.e. non-propagating cracks). There was a deceleration of crack growth rate in the transition process where the dominant crack formed from the multiple microcracks.

A PROBABILITY ANALYSIS OF HEART RATE VARIABILITY FOR HEART TRANSPLANT AND MYOCARDIAL INFARCTION PATIENTS AND FOR HEALTHY SUBJECTS

We present a probability analysis of RR interval series. The analysis is based on a subdivision of the RR interval series into segments — here called m-segments — ranging from one local RR maximum value to the consecutively following local RR maximum value; such segments represent full cycles of acceleration followed by deceleration of the heart rate. We analyze the properties of m-segments in terms of the probability of observing j RR values in the segment and in terms of the probability of observing a change of Δj in going from one m-segment to the following m-segment. We also calculate the rms-values, σm, of the m-segments and introduce an entropy measure to characterize the RR interval series. Further, we present a simple model for phase-space-trajectory plots for RR interval series and an estimate of the spectral properties in terms of the parameters j and σm. The results are based on 24-hour RR interval series for ten heart transplant patients, with a total of 23 recordings, for 326 myocardial infarction patients and 104 healthy subjects. The results obtained show characteristic differences between the behavior of the three groups, but no attempt at a clinical interpretation is made.

Uterus inferior segment compression as a clinical test for diagnosing nuchal cord.

To investigate sensitivity, specificity, positive and negative predictive values and accuracy of uterus inferior segment compression (UISC) as clinical test for diagnosing nuchal cord. This test is used empirically. The clinical test was applied to 214 pregnant women in the first phase of delivery with single cephalic fetuses. The main observation was deceleration of the fetal heart rate by performing the clinical test in the presence of nuchal cord. Statistic analysis was done by chi2-test. The results were: sensitivity 35.7%, specificity 84.8%, positive predictive value 45.4%, negative predictive value 78.8% and accuracy 71.9% (chi2=10.66, p=0.0011). The UISC could be used as a tool in the initial exploration of the term pregnant woman in labor without complications to rule out the presence of nuchal cord. When the UISC test is positive, close vigilance is recommended along with the availability of an emergency team in case of fetal distress.

Effect of surfactants on peroxidase activity: IV. Effect of milk lipids and fatty acid salts

The effect of surfactants, lipids and fatty acid salts isolated from cow milk on the activity of hemecontaining horseradish peroxidase in solution was studied. As the surfactant concentration increases, the rate of the enzymic reaction successively decreases, increases, and again decreases, down to zero in the case of the fatty acid salts. The initial deceleration of the reaction rate results from the enzyme inhibition. The subsequent increase is caused by an improved accessibility for the substrate and the enhanced activity of the catalytic site of the enzyme due to its immobilization in the surfactant aggregates. A shielding of the protein by these aggregates can explain the secondary deceleration of the enzymic reaction rate. The general character of the dependence is similar and does not depend on the surfactant structure for a series of fatty acid salts and phospholipids; however, it is quite different in the case of cholesterol and sphingomyelin.

Con: Magnesium should not be administered to all coronary artery bypass graft surgery patients undergoing cardiopulmonary bypass

Con: Magnesium should not be administered to all coronary artery bypass graft surgery patients undergoing cardiopulmonary bypass