Effect Of Peak Research Articles

An eco-evolutionary model for demographic and phenological responses in migratory birds.

Many migratory birds have changed their timing of arrival at breeding grounds in response to recent climate change. Understanding the adaptive value and the demographic consequences of these shifts are key challenges. To address these questions we extend previous models of phenological adaptation to climate change under territory competition to include feedback from population dynamics, winter survival and habitat productivity. We study effects of improved pre-breeding survival and of earlier food abundance peak. We show that phenological responses depend strongly on equilibrium population density via effects on territory competition. When density is high, improved pre-breeding survival affects selection pressures more than shifts of the resource peak. Under certain conditions, an advanced food peak can even select for later arrival due to competitive release. Improved pre-breeding survival has positive effects on population density that in many cases is stronger than negative effects of an advanced food peak. The fraction of young in the population decreases in all scenarios of change, but food peak shifts only affect population structure marginally unless population density is low. This work thus provides several missing links between phenological adaptation and demographic responses, and augments the toolbox for interpreting ongoing phenological shifts in migratory birds. We illustrate the utility of our model by explaining different patterns in demographic trends and phenological shifts in populations of Pied flycatchers (Ficedula hypoleuca) across Western Europe.

Simulation of femtosecond laser pulse propagation in air

We studied the effects of different peak powers and initial pulse shapes during femtosecond laser pulse propagation in air. The full 3D simulation result showed that there was a bundle of discontinuous filaments along intense femtosecond laser pulse propagation axis. Comparisons between pulses with different input peak powers and initial pulse shapes could help us to find ways for forming long and uniform plasma channel in air.

A downward signal processing method for rotary steerable drilling system based on signal similarity

Abstract To identify downhole command signals accurately and efficiently with negative fluid pulse intervals in the rotary steerable drilling engineering and solve the complex operation and high error rate problems in the command identification and explanation process of downhole receivers, this paper presents a signal process method based on signal similarity principle. In this method, command instructions expressed by drilling fluid pulse width signal are obtained by comparing the self-correlation degree of sampling signal amplitudes at each interval, and the downhole sampling signals are compared interval by interval according to a fixed rule, and command identification is achieved by three steps, i.e. judgment for the start of signal, calculation for digital bits of the command, and assembling of command word. The recursive practical algorithms suitable for downhole processing are proposed. The results show that the method can simplify operation program and improve the reliability and ability of interference killing for the signal identification, and is especially good for overcoming the effects of peak and periodic interference on time counting and the effects of inertia of transmitting channel and low frequency noise on signal jump edge judging.

Suppression of Peak Noise Caused by Time Delay of the Anti- Noise Source

According to the peak noise caused by the delay of the anti noise source, analysis of the periodic signal and non-periodic random signals of different frequencies and different signal superimposed analog delay the case after the noise reduction effect and generated peak noise, and peak generated by delay noise process, proposed a kind of fuzzy control inhibit active noise control resulting from the peak signal suppression strategy, simulation of fuzzy control of noise reduction and the effect of peak.

HMM–TLP correlation for system-efficient ESD design

A linear correlation between 100ns TLP and the second HMM peak current was found for several common types of protection devices. A detailed thermal analysis offers a straightforward explanation of the correlation factor in terms of pulse duration. It is found that the thermal effect of the first HMM peak can be ignored. The impact of non-thermal failure mechanisms, e.g. gate oxide breakdown due to an over-voltage, which may limit the validity of the correlation are explored for a complete system, which includes additional components. The results from this investigation are essential for proper application of the System-efficient ESD Design (SEED) methodology.

Contrast Evaluation for a Dual Head SPECT System with Different Energy PeakingDrift

Gamma cameras contain energy discriminators that allow only those photons within a specified energy range to be recorded. The process of setting this energy window is called “peaking” the camera. A spontaneous shift in the peak of one head of a triple-head gamma camera was reported to cause an artifact that mimicked ischemia on 201Tl-chloride myocardial SPECT. The characteristic energy distribution results from the collection of total photon energy absorbed by the detector. Physically peaked detectors will center the energy window on the photo peak of selected isotope. Aim of the study: Our aim is to evaluate the effect of energy peak drifting for both imaging heads on the image contrast in SPECT. Materials and methods: Using a dual head gamma camera, the SPECT phantom with its inserts was scanned using a fixed acquisition protocol and image reconstruction parameters but with changing the energy peak window adjustment which was operated for both heads at different values starting from 120 KeV up to 160 KeV with incremental step of 5 KeV, and the window width was adjusted to be 15% as used in the clinical applications.Results: Our results shows a fluctuation in the image contrast, as there was a gradual increase in the contrast value from 120 KeV setting up to 140 KeV by 31 % and also there was a gradual decrease in the contrast value from 140 KeV setting up to 160 KeV setting by 15 %. The clinical verification for these results was done on cardiac patient who underwent a cardiac scan twice with the normal gamma camera peak setting and then with off-peak setting at 120 KeV (which gives the lowest contrast value for the phantom study). And the case interpretation results confirm the phantom results as there was a significant change in the uptake in the left ventricle wall, with also a verification from the quantitative results by the Quantitave comparison using the quantitative gated SPECT data, that shows a 9% difference in the EF calculated value from the normal to the off-peak setting, which may affect the interpretation and in consequence the further treatment of the patient.Conclusion: The energy window peaking for the gamma camera has a proven effect on the planar images, and this was explained and proved in our study to have a significant effect on the contrast of the SPECT images which will affect the interpretation of the clinical results.

The morning blood pressure surge

The morning blood pressure surge

The effects of peak and mid-luteal estradiol levels on in vitro fertilization outcome

To evaluate the role of peak E2 level and its ratio to mid-luteal E2 level on implantation and clinical pregnancy rates in patients undergoing IVF cycles. A retrospective study was designed covering 106 patients who were admitted to IVF Unit between June and October 2008. The patients were divided into two groups with respect to peak E2 levels. Ovulation induction has been done via standard long agonist protocol. Blood samples were drawn on the day of (hCG) administration and 8 days after embryo transfer for serum E2, progesterone measurements. The mean peak E2 level was 2,697.4 ± 1,453 pg/ml (range 684-4,983 pg/ml. The number of retrieved oocytes, luteal E2 level, peak E2 level and E2 ratio were significantly higher in E2 >2,500 group, however, the implantation rate was significantly lower in this group. There were statistically significant differences in peak E2 levels, luteal E2 levels, retrieved oocytes, E2 ratios; of the women who got pregnant and did not get pregnant, all the above parameters were significantly higher in non-pregnant group. According to E2 ratios, the clinical pregnancy rate was highest in group 1 and significantly lowest in group 3. This study has shown that the high E2 level and mid-luteal decline of E2 which were defined as peak E2 level/mid-luteal E2 level were predictive for implantation rate in IVF cycles.

건물의 외주부 존에 대한 동적 부하모델 이용 피크냉방부하 저감효과 분석

In this paper, inverse building modeling was applied to building perimeter zones which have different window orientation. Two test zones of east-facing and west-facing zones in ERS(Energy Resource Station) building, which is representative of small commercial building, was used to test performance of cooling load calculation and peak cooling load reduction. The dynamic thermal load model for the east and west zone was validated using measured data for the zones and then it was used to investigate the effect of peak cooling load reduction by adjustment of indoor cooling temperature set points during on-peak time period. For the east zone, the peak load can be reduced to about 60% of the peak load for conventional control even without any precooling. For the west zone, PLR is nearly independent of the start of the on-peak period until a start time of 1pm. Furthermore, PLR has a small dependence on the precooling duration. Without any precooling, the peak cooling load can be reduced to about 35% of the peak load associated with conventional control.

Choice of electrical motor and transmission in mechatronic applications: The torque peak

This paper deals with the effect of the torque peak on the choice of electrical motor and transmission suitable for moving a joint. We propose a method that allows us to explain the general form of the resolving diagram and to identify the load conditions that are directly responsible for it. In consequence, this method permits the designer to obtain the equation of this curve and to find analytically the admissible motors and the corresponding transmission ratio ranges.

Behavioral and Electrophysiologic Binaural Processing in Persons with Symmetric Hearing Loss

Binaural hearing improves our ability to understand speech and to localize sounds. Hearing loss can interfere with binaural cues, and despite the success of amplification, ∼25% of people with bilateral hearing loss fit with two hearing aids choose to wear only one (e.g., Brooks and Bulmer, 1981). One explanation is reduced binaural processing, which occurs when the signal presented to one ear interferes with the perception of the signal presented to the other ear (e.g., Jerger et al, 1993). Typical clinical measures, however, are insensitive to binaural processing deficits. The purpose of this study was to determine the extent to which behavioral measures of binaural performance were related to electrophysiological measures of binaural processing in subjects with symmetrical pure-tone sensitivity. The relationship between middle latency responses (MLRs) and behavioral performance on binaural listening tasks was assessed by Spearman's rho correlation analyses. Separate repeated measures analyses of variance (RMANOVAs) were performed for MLR latency and MLR amplitude. Nineteen subjects were recruited for the present study based on a clinical presentation of symmetrical pure-tone sensitivity with asymmetrical performance on a word-recognition in noise test. This subpopulation of patients included both subjects with and subjects without hearing loss. Monaural and binaural auditory processing was measured behaviorally and electrophysiologically in right-handed subjects. The behavioral tests included the Words-in-Noise test (WIN), the dichotic digits test (DDT), and the 500 Hz masking level difference (MLD). Electrophysiologic responses were measured by the binaural interaction component (BIC) of the MLR. The electrophysiological responses were analyzed to examine the effects of peak (Na, Pa, and Nb) and condition (monaural left, monaural right, binaural, and BIC) on MLR amplitude and latency. Significant correlations were found among electrophysiological measures of binaural hearing and behavioral tests of binaural hearing. A strong correlation between the MLD and the binaural Na-Pa amplitude was found (r = .816). The behavioral and electrophysiological measures used in the present study clearly showed evidence of reduced binaural processing in ∼10 of the subjects in the present study who had symmetrical pure-tone sensitivity. These results underscore the importance of understanding binaural auditory processing and how these measures may or may not identify functional auditory problems.

Label-free colorimetric detection of trace cholesterol based on molecularly imprinted photonic hydrogels

A novel colorimetric sensor for cholesterol assay was constructed by combining a molecular imprinting technique with photonic crystals. The molecularly imprinted photonic hydrogel (MIPH) film was prepared by a non-covalent, self-assembly approach using cholesterol as a template molecule, and exhibited a highly ordered three-dimensional macroporous structure characterized by scanning electron microscopy under the optimized imprinting conditions. Various factors affecting rebinding of cholesterol are discussed along with recognition specificity studies on its analogues of stigmasterol and ergosterol through estimation of UV-Vis and electrochemical impedance spectroscopy. The MIPH film generated a significantly readable optical signal directly self-reporting within less than 2 min upon binding cholesterol. The colorimetric measurement of cholesterol concentration strongly relies on the fact that the blue shift effect of the Bragg diffraction peak of the MIPH is gradually enlarged with the increase of cholesterol amounts. The detection level approached 10−13 g mL−1, which is comparable to that of fluorescence measurements. The simultaneous possession of high selectivity, high sensitivity, high stability, easy operation and being label-free enables this sensor to be potentially applicable for rapid on-site detection of trace cholesterol.

Study of anodic voltage on properties of complex nanocrystalline carbonitrided titanium fabricated by duplex treatments

Up to the fourth moment distribution of carbonitride nanocrystallites produced by duplex treatments of surface nanocrystallisation and bipolar pulsed plasma electrolytic carbonitriding on commercially pure titanium was investigated by means of high precision figure analysis. Skewness and kurtosis of Gussian distribution curves have been studied, and the effect of anodic voltage peak has been determined. The usage of lower peaks of anodic voltage is more suitable for achieving lower sizes of carbonitride nanocrystallites. Surface roughness of treated samples was measured, and it has been observed that there is an optimum level of anodic voltage peak for surface roughness increasing (difference between two measured data).

Method for analyzing E×B probe spectra from Hall thruster plumes

Various methods for accurately determining ion species' current fractions using E x B probes in Hall thruster plumes are investigated. The effects of peak broadening and charge exchange on the calculated values of current fractions are quantified in order to determine the importance of accounting for them in the analysis. It is shown that both peak broadening and charge exchange have a significant effect on the calculated current fractions over a variety of operating conditions, especially at operating pressures exceeding 10(-5) torr. However, these effects can be accounted for using a simple approximation for the velocity distribution function and a one-dimensional charge exchange correction model. In order to keep plume attenuation from charge exchange below 30%, it is recommended that pz < or = 2, where p is the measured facility pressure in units of 10(-5) torr and z is the distance from the thruster exit plane to the probe inlet in meters. The spatial variation of the current fractions in the plume of a Hall thruster and the error induced from taking a single-point measurement are also briefly discussed.

Primary activity standardization of 57Co by sum-peak method

The sum-peak method was applied to standardize a 57Co solution within the framework of an international comparison organized by International Atomic Energy Agency, in 2008, aimed toward international traceability of activity measurements. A planar germanium detector was used with the sources placed on top of the detector for activity determination measurements. An analytical expression for accidental summing correction was derived and the effect of the germanium characteristic KX-ray escape peak of 112 keV was taken into account. The standard uncertainty associated to the activity concentration value was 0.37% and the result was compared with other measurement methods.

Effect of bit depth and kVp of digital radiography for detection of subtle differences

The purpose of this study is to investigate the effects of different bit depths and kilovoltage peak (kVp) values used in intraoral digital radiography on observer performance in detecting subtle radiographic density differences. Using an intraoral CCD sensor set at 8- or 12-bit depth, kVp set at 60 or 70, and 14 different exposure times, digital radiographs were acquired of a specially designed aluminum step-wedge phantom with small holes of different depths in each step. Ten observers examined all images. The observers counted more holes with the 12-bit images compared with the 8-bit images, particularly at 60 kVp. Significantly more holes were also counted with images taken at 70 kVp compared with those taken at 60 kVp. Regarding the detection of subtle radiographic density differences, 12-bit images and 70 kVp were superior to 8-bit images and 60 kVp.

Determination of Trace of Cobalt in Complex Matrices by Adsorptive Stripping Voltammetry at a Lead Film Electrode

AbstractAn adsorptive stripping voltammetric procedure for the determination of cobalt in a complex matrices at an in situ plated lead film electrode was described. The procedure exploits the enhancement effect of a cobalt peak observed in the system Co(II)–nioxime–piperazine‐1,4‐bis(2‐ethanesulfonic acid)–cetyltrimethylammonium bromide. The calibration graph was linear from 5×10−10 to 2×10−8 mol L−1 and from 1×10−10 to 1×10−9 mol L−1 for the accumulation times 120 and 600 s, respectively. The detection limit (based on the 3 σ criterion) for Co(II) following accumulation time of 600 s was 1.1×10−11 mol L−1. The interference of high concentrations of foreign ions and surfactants was studied.

Microstructures and electrochemical characteristics of Mm 0.3Ml 0.7Ni 3.55Co 0.75Mn 0.4Al 0.3 hydrogen storage alloys prepared by mechanical alloying

The as-cast alloy with the composition of Mm 0.3Ml 0.7Ni 3.55Co 0.75Mn 0.4Al 0.3 prepared by induction melting was milled for 6, 15, 40 and 50 h in this work. The microstructures of alloys were analyzed by XRD and DSC. Two broadening effects of XRD peak caused by crystallite and microstrain were separated by approximate function method and least square method. Crystallite sizes and microstrains of the alloys were calculated. The results show that alloys milled for 6 h or 15 h consist of nanocrystalline and polycrystalline phase. Lattice parameters (a, c) and volumes of alloy increase with the increasing milling time, whereas the ratio of c/ a keep constant. Moreover, the crystallite sizes decrease and the microstrains in the alloys increase first and then decrease with the increase of milling time. The alloys milled for 40 h or 50 h transform partly into amorphous structures. The maximum discharge capacities of alloys decrease with the increase of milling time. The cycle stabilities of the milled alloys are better than those of the as-cast. And they increase with the increasing milling time.

On collisional energy transfer in recombination and dissociation reactions: A Wiener–Hopf problem and the effect of a near elastic peak

The effect of the large impact parameter near-elastic peak of collisional energy transfer for unimolecular dissociation/bimolecular recombination reactions is studied. To this end, the conventional single exponential model, a biexponential model that fits the literature classical trajectory data better, a model with a singularity at zero energy transfer, and the most realistic model, a model with a near-singularity, are fitted to the trajectory data in the literature. The typical effect of the energy transfer on the recombination rate constant is maximal at low pressures and this region is the one studied here. The distribution function for the limiting dissociation rate constant k(0) at low pressures is shown to obey a Wiener-Hopf integral equation and is solved analytically for the first two models and perturbatively for the other two. For the single exponential model, this method yields the trial solution of Troe. The results are applied to the dissociation of O(3) in the presence of argon, for which classical mechanical trajectory data are available. The k(0)'s for various models are calculated and compared, the value for the near-singularity model being about ten times larger than that for the first two models. This trend reflects the contribution to the cross section from collisions with larger impact parameter. In the present study of the near-singularity model, it is found that k(0) is not sensitive to reasonable values for the lower bound. Energy transfer values DeltaE's are also calculated and compared and can be similarly understood. However, unlike the k(0) values, they are sensitive to the lower bound, and so any comparison of a classical trajectory analysis for DeltaE's with the kinetic experimental data needs particular care.

The Effect of Peak and Current Serum Panel-Reactive Antibody on Graft Survival

Background Preformed antibodies against HLA antigens are known risk factors for early graft loss. Pretransplantation panel-reactive antibody (PRA) is often used to estimate the degree of sensitization. This study was conducted to determine the risk of early graft loss among subjects with a PRA cutoff value of 10%. Objectives To evaluate the influence on 1-year graft survival of pretransplant recipient sensitization using 10% peak and current PRA cutoff values. Methods From January 1988 to July 2007, T-cell and B-cell PRA data were available for 247 (41%) and 241 (40%) patients, respectively. Medical records were reviewed for graft survival, current PRA value, and peak PRA value (both T and B cell). Complement-dependent cytotoxicity (CDC) is the only method of PRA identification in this study. We analyzed the correlation between PRA level and graft survival. Results Current T-cell PRA > 10% was significantly associated with poorer 1-year graft survival when compared with those with PRA ≤ 10% in kidney transplantation from both donor sources: 48.6% versus 86.3% ( P = .007) for living donor 94.7% versus 70.0% ( P = .029) for deceased donor. Most of the graft losses in recipients with a high PRA occurred within the first 3 months posttransplantation. Conclusion In our experience, current serum T-cell CDC PRA value > 10% was significantly associated with a decreased 1-year graft survival; interventions will be required to preserved graft function in these high-risk individuals.