The effects of baseline heart rate recovery normality and exercise training protocol on heart rate recovery in patients with heart failure

Objective: It is unclear which exercise training protocol yields superior heart rate recovery (HRR) improvement in heart failure (HF) patients. Whether baseline HRR normality plays a role in the improvement is unknown. We hypothesized that an exercise training protocol and baseline HRR normality would be factors in altering HRR in HF patients. Methods: In this prospective, randomized, controlled and 3 group parallel study, 41 stable HF patients were randomly assigned to 3-timesweekly training sessions for 12 weeks, consisting of i) 30 minutes of interval training (IT) (n=17, 63.7±8.8 years old) versus ii) 30 minutes of continuous training (CT) (n=13, 59.6±6.8 years old) versus iii) no training (CON) (n=11, 60.6±9.9 years old). Each patient had cardiopulmonary exercise testing before and after the training program. Maximum heart rates attained during the test and heart rates at 1 and 2 min (HRR1 and HRR2) during the recovery phase were recorded. Paired samples t-test or Wilcoxon signed-rank test was used for comparisons before and after training. One-way ANOVA or Kruskal-Wallis variance analysis was used for comparisons among groups. Results: HRR1 was unchanged after training. HRR2 improved in the IT group after training, and post-training HRR2 values were significantly faster in the IT group than in controls. Both HRR1 and HRR2 was significantly faster, irrespective of exercise protocol in patients with abnormal baseline values after training. Conclusion: HRR1 did not improve after training. HRR2 improved only in the IT group. Both HRRs in patients with abnormal baseline values improved after both exercise protocols. IT might be superior to CT in improving HRR2. Baseline HRR might play a role in its response to exercise. © 2015 by Turkish Society of Cardiology

A low-complexity time-domain MMSE channel estimator for space-time/frequency block-coded OFDM systems

Focusing on transmit diversity orthogonal frequency-division multiplexing (OFDM) transmission through frequency-selective channels, this paper pursues a channel estimation approach in time domain for both space-frequency OFDM (SF-OFDM) and space-time OFDM(ST-OFDM) systems based on AR channel modelling. The paper proposes a computationally efficient, pilot-aided linear minimum mean-square-error (MMSE) time-domain channel estimation algorithm for OFDM systems with transmitter diversity in unknown wireless fading channels. The proposed approach employs a convenient representation of the channel impulse responses based on the Karhunen-Loeve (KL) orthogonal expansion and finds MMSE estimates of the uncorrelated KL series expansion coefficients. Based on such an expansion, no matrix inversion is required in the proposed MMSE estimator. Subsequently, optimal rank reduction is applied to obtain significant taps resulting in a smaller computational load on the proposed estimation algorithm. The performance of the proposed approach is studied through the analytical results and computer simulations. In order to explore the performance, the closed-form expression for the average symbol error rate (SER)probability is derived for the maximum ratio receive combiner(MRRC). We then consider the stochastic Cramer-Rao lower bound(CRLB) and derive the closed-form expression for the random KL coefficients, and consequently exploit the performance of the MMSE channel estimator based on the evaluation of minimum Bayesian MSE. We also analyze the effect of a modelling mismatch on the estimator performance. Simulation results confirm our theoretical analysis and illustrate that the proposed algorithms are capable of tracking fast fading and improving overall performance. Copyright © 2006 Hindawi Publishing Corporation. All rights reserved

Cutoff rate for fixed-composition on-off keying over direct detection photon channels

Cataloged from PDF version of article.[Ankara]: The Department of Electrical and Electronics Engineering and the Institute of Engineering and Sciences of Bilkent Univ., 1990.Includes bibliographical references (p.50-51).In this thesis, we consider direct detection photon channel with peak and average power constraints. This channel is modelled as a binary input discrete memoryless channel. We study the cutoff rate for different modulation formats on this channel since it is a measure of decoding complexity when sequential decoding is used and also, it gives an upper bound for the probability of error which decreases exponentially with the constraint length of convolutional code. Cutoff rates for the ensembles of fixed-composition and independent-letters codes along with ON-OFF keying are computed numerically and also some bounds are given. Cutoff rates versus signal-to-noise ratio or peak power are plotted for blocklengths of N=40,100 and for both ensembles. Comparison of cutoff rates for these two ensembles shows that for the direct detection photon channel the cutoff rate of fixed-composition ensemble is significantly greater than that of independent-letters ensemble for small values of signal-to-noise ratio and when the average power is a small fraction of peak power, say, 5-30%. In an uncoded system, for achieving a probability of error P(E)=(10 to the power -9), we should send 10 photons/slot with rate R=1 bit/slot, resulting in an efficiency of 0.1 bits/photon.However, using coding we can make probability of error arbitrarily small achieving an efficiency of 1 bit/photon. Also, some remarks on the implementation of fixed-composition trellis codes and on multi-level signalling instead of ON-OFF keying are given in conclusions.by Toygar, M. Şenol.M.S

Experimental investigation of the effects of beach drainage on erosion in fine-grained beaches

Plajlar ince kumlardan iri kayalara kadar değişen büyüklükte kayaların birikmesiyle oluşmuş jeolojik bölgelerdir. Plajlar kara, hava ve deniz birleşiminde yer almakta olup morfolojileri dalga mekaniği, katı madde özellikleri ve mekaniği, plaj yeraltı suyu akımı ve mekaniği ile rüzgar etkilerinin etkileşimine bağlıdır. Sahil drenajı, sahil altına yerleştirilen perfore drenaj boruları vasıtasıyla dalga ve yeraltı sularının drene edilmesi ve böylece yeraltı su seviyesinin düşürülmesi ile sızma oranının arttırılması prensibine dayanır. Araştırmada ince taneli kuma sahip sahillerde sızma oranının arttırılması ile erozyonun nasıl değişeceği deneysel olarak incelenmiştir. Çalışmanın amacı değişik dalga özelliklerinin etkisinde drenaj borusunun farklı konumlarında profil şeklinin ve drenaj debisinin tayin edilmesidir. Bu amaçla fiziksel bir model geliştirilmiş ve basit analitik çözümler önerilmiştir. Bu çalışmalar daha sonra düzenli dalga koşullarında yapılan laboratuvar çalışmaları ile karşılaştırılmıştır. Drenaj debisinin tahmini, inşaa edilecek su toplama kuyusunun hesabında ve bu kuyudan suları denize deşarj edecek pompa kapasitesinin tayininde kullanılmaktadır. Öte yandan, değişik dalga ve drenaj borusu yerleşim yerleri için erozyon alanının tahmin edilmesi, kıyı duvarları ve kıyı kaplamaları gibi çeşitli yapıların stabilitelerinin belirlenmesi açısından önemlidir. Bu çalışmada hem drenaj debisi hem de erozyon alanı parametrelerinin tahmini için denklemler önerilmiştir. Sahil drenajı ile erozyon alanında azalma yaşanmıştır. Bunun nedeni olarak yer altı su seviyesinin düşmesi ile sızma oranında artma ve buna mukabil katı madde efektif ağırlığında artış söylenebilir. Profil verileri incelendiğinde erozyon alanındaki artışın en önemli nedeni ise dalga tırmanma yüksekliğinde yaşanan azalma görülmüştür.  Anahtar Kelimeler: Sahil drenajı, erozyon, stabilizasyon.Beaches play important roles in both the dissipation of wave energy and for the recreational purposes. They are generally in dynamic equilibrium. But, due to increasing industrial activities and population, human interference into the beaches occurs and the dynamic equilibrium deteriorates. In order to control the cross-shore and alongshore sediment transport in eroding beaches, some structures like breakwaters, groins, seawalls are constructed. These structures are composed of massive concrete blocks which lead to loss in aesthetic vision. Moreover, these structures are very difficult to relocate after construction. Beach drainage is an erosion control method studied in-situ, laboratory and numerically and offers an alternative to massive coastal control structures. Main philosophy lying under this method is lowering the water table and increasing the infiltration through the sediment matrix. As the infiltration rate increases, the probability of liquefaction and effective weight reduction of sediments will be reduced. Also, water that infiltrates during the wave runup will lead to reduction in flow velocity during both in runup and run-down phases. This reduction in flow velocity will lead to reduction in shear stresses. Recently, some numerical studies claim that for fine sediments, in case of infiltration, erosion occurs due to offshore migration of sediments. On the other hand, reports of in-situ investigations reveal that, in case of infiltration either the beach accretes or the erosion is reduced. Experiments are conducted in a narrow flume with 22m in length, 1m in width and 80cm in depth. Slope of beach profile is always kept constant (1:5), the profile and drainage flow rate data are measured.  The median grain size of the sediment is d50=0.3 mm. The diameter of the drainage pipe is 50mm and is laid all width of the flume. The pipe is perforated in 8mm holes to allow the water suction. Geotextile sheet is wrapped over the pipe to prevent the holes from sediment clogging. 6 drainage pipe locations are determined; beach profiles and drainage flow rates are measured in these locations. Between the beach head and the ground water trench, geotextile filter layer is placed to prevent clogging of the holes, which allow the ground water flow through the beach. Ground water level is always kept constant in all experiments as the same as the still water level. According to the experimental analysis, the waves which have lower height than 5.5 cm do not result in erosion in the profile in no-drain case. The area of the erosion is almost linearly increasing with wave height. In case of drainage, the wave height which does not result in erosion in the profile is observed as 8cm. Center of gravity of the offshore bar migrates landwards as the drainage pipe location approaches the intersection of beach profile and still water line. There is no direct relation between the drainage flow rate and erosion area. The important factor is that whether the runup/rundown wave water or the existing ground water is drained. The ground water is drained as the pipe location migrates landwards. According to the experimental analysis results, the most obvious reduction in the erosion area is observed when the pipe is placed in location (2). When the data measured in location (2) is compared with no-drain data, erosion area reduction rate is reduced when the wave height is increased. When the wave height is increased up to 25 cm, drainage has no advantage to reduce erosion Dimensionless drainage flow rate and dimensionless erosion area parameters are derived analytically by using the data measured in pipe locations of 1, 3, 4 and 5. Derived equations are verified by using locations 2 and 6. The increase in the infiltration rate by lowering the water table leads to reduction in the effective weight of the sediments and decrease in the flow velocity of the runup/rundown swash flows. When the profile graphs are investigated, the main reason for the erosion reduction should be the reduction of the wave runup height. Increase in the infiltration rate leads to reduction of the wave runup wave flow velocity and quantity, resulting in the decrease of runup limit of water waves. In the down-rush phase, the flow velocity is also reduced and the ability to carry sediments is decreased. Keywords: Beach drainage, dewatering, erosion, stabilisation

Updating of the soil map of the Çukurova University campus area by using geographic information system (gıs)

The aim of this study is to update the previous soil map of the Çukurova University campus which was completed in 1974. The widely distributed soil series were selected on previous soil map. Soil series are reidentified and re-sampled in the present study. Physical and chemical analyses were repeated on newly collected soil samples. Satellite image of Quickbird dated 17th of August 2004 were employed for the unsupervised classification. All classes were checked by field truth studies. Previous soil series borders were taken into account during field surveys. The ILSEN software is used to generate Suitability Class of Agricultural Applications (SCAA) and Potential Land Use (PLU). Land Use Capability map (LUC) was made by considering some characteristics which are limiting agricultural managements. Current Land Use map (CLU) is produced via field observations for each land use. Finally, we determined that there is no significant change between 1974 and updated maps for soil series. But there are some differentiations for soil phases since 1974. All maps of the study are produced at 1:5000 scales

Is amygdala size correlated with stress?

Background: One of the important mechanisms that regulate the stress response of the body is hypothalamic pituitary adrenal axis. One of the structures activating this axis is amygdala. We have seen people around who react calmer and cooler to very stressful situations. Are people with smaller amygdala really calmer? Or, can we say that the bigger the amygdala, which is the trigger of the body’s response to stress, the more a person panics? Aim of the study is to compare the saliva cortisol levels and amygdala volume.Materials and methods: Study conducted with 63 male students. Magnetic resonance images of students were taken before their final exam to calculate amygdala volumes. Saliva samples of all students were taken two times to detect cortisol levels in saliva. First one was 20 days before the final exam and second one was on the exam day. We assumed that the students were stressful on exam day.Results and Conclusions: No statistically significant correlation was found between saliva cortisol levels and amygdala volume in the study