The estimation of mean duration from stage frequency data

Summary A simple method of estimating duration from stage frequency data is derived. A simulation model of the passage of individuals through a particular stage in the life-cycle is presented, together with results from the model on the influence of recruitment, development and mortality on the parameters used in the estimation of stage duration. The application of the method to field data is described and a test example, using simulated data, is given.     

A physical model of acoustic effects of ultrahigh frequency fields on biological systems

A physical model of radiosound based on the stimulation of mechanical oscillations in liquid media at adsorption of SHF impulse energy is presented. It is shown that a limited liquid volume can be considered as an acoustic resonator with self oscillation frequency. At definite relationships between the succession frequency and impulse duration interference takes place. Oscillograms of recorded mechanical oscillations are presented. The low frequency type of radiosound is explained. A conclusion is made concerning the reliability of the proposed method for investigating radiosound.     

Study of high-power pulsed RF generators based on a hollow-cathode discharge

Results are presented from studies of physical principles underlying operation of high-power pulsed RF generators based on a hollow-cathode discharge (HCD). Various types of instabilities that may occur in an HCD and lead to 100% RF modulation of the electrode voltage in the megahertz frequency range are discussed. The design, electric characteristics, and operating modes of HCD-based RF generators are described. Results of experiments aimed at increasing the power and duration of RF pulses are presented. It is demonstrated that such devices are capable of generating 10- to 220-MHz pulses with a power of up to 8 MW, duration of up to 10 μs, and repetition rate of 1 kHz. The discharge chambers of such generators are very simple in design, they have very high stability, and their efficiency reaches 35%.     

Acoustic emissions of Sorex unguiculatus (Mammalia: Soricidae): Assessing the echo‐based orientation hypothesis

Shrew species have been proposed to utilize an echo‐based orientation system to obtain additional acoustic information while surveying their environments. This system has been supported by changes in vocal emission rates when shrews encounter different habitats of varying complexity, although detailed acoustic features in this system have not been reported. In this study, behavioral experiments were conducted using the long‐clawed shrew (Sorex unguiculatus) to assess this orientation system. Three experimental conditions were set, two of which contained obstacles. Short‐click, noisy, and different types of tonal calls in the audible‐to‐ultrasonic frequency range were recorded under all experimental conditions. The results indicated that shrews emit calls more frequently when they are facing obstacles or exploring the experimental environment. Shrews emitted clicks and several different types of tonal calls while exploring, and modified the use of different types of calls for varying behavior. Furthermore, shrews modified the dominant frequency and duration of squeak calls for different types of obstacles, that is, plants and acrylic barriers. The vocalizations emitted at short inter‐pulse intervals could not be observed when shrews approached these obstacles. These results are consistent with the echo‐based orientation hypothesis according to which shrews use a simple echo‐orientation system to obtain information from their surrounding environments, although further studies are needed to confirm this hypothesis.     

A New Quantitative Technique for Categorizing Whistles Using Simulated Signals and Whistles from Captive Bottlenose Dolphins (Delphinidae,Tursiops truncatus)

A widespread problem in the study of animal vocalizations is evaluating the acoustic similarity of signals both between individuals of a social group and between social groups. This problem becomes especially salient when classifying the narrow-band frequency-modulated signals, such as whistles, found in many avian and mammalian species. Whistles are usually characterized by their relative change in frequency over time, known as whistle ‘contour’. Measuring such a characteristic is difficult as it is not a single measurement, such as the mean frequency or duration of a signal, but several associated measurements of frequency across time. This paper reports on a new quantitative technique for determining whistle types based on whistle contour similarity and an application of this technique to the whistles of bottlenose dolphins to demonstrate its utility. This ‘contour similarity’ technique (CS technique) uses cluster analysis to group the correlation coefficients of frequency measurements from a data set of signals. To demonstrate the efficacy of this CS technique, three data sets were analysed, two using computer-generated signals and a third using adult bottlenose dolphin whistles, to (1) examine the efficacy of correlation coefficients for grouping signals by their similarity in whistle contour and (2) determine the viability of this technique for categorizing bottlenose dolphin whistles. Measured actual frequencies and correlation matrices from the four simulated signal types and a correlation matrix from the whistles of five captive adult bottlenose dolphins were each subjected to K-means cluster analysis and the resulting signal types were evaluated. Results indicated that the technique grouped actual frequencies according to the amount of shared actual frequencies and grouped correlation coefficients successfully according to signal contour. This result endured even if contours differed in overall duration or actual frequency or were expanded or compressed with respect to frequency or time. The results suggest that this approach is a viable method for assigning whistle contours to categories in bottlenose dolphins or any other species with narrow-band, frequency-modulated signals.     

Diversity in the structure of electrocommunication signals within a genus of electric fish,<Emphasis Type="Italic"> Apteronotus</Emphasis>

Some gymnotiform electric fish modulate their electric organ discharge for intraspecific communication. In Apteronotus leptorhynchus, chirps are usually rapid (10-30 ms) modulations that are activated through non- N-methyl- d-aspartate (non-NMDA) glutamate receptors in the hindbrain pacemaker nucleus. Males produce longer chirp types than females and chirp at higher rates. In Apteronotus albifrons, chirp rate is sexually monomorphic, but chirp structure (change in frequency and amplitude during a chirp) was unknown. To better understand the neural regulation and evolution of chirping behavior, we compared chirp structure in these two species under identical stimulus regimes. A. albifrons, like A. leptorhynchus, produced distinct types of chirps that varied, in part, by frequency excursion. However, unlike in A. leptorhynchus, chirp types in A. albifrons varied little in duration, and chirps were all longer (70-200 ms) than those of A. leptorhynchus. Chirp type production was not sexually dimorphic in A. albifrons, but within two chirp types males produced longer chirps than females. We suggest that species differences in chirp duration might be attributable to differences in the relative proportions of fast-acting (non-NMDA) and slow-acting (NMDA) glutamate receptors in the pacemaker. Additionally, we map species difference onto a phylogeny and hypothesize an evolutionary sequence for the diversification of chirp structure.     

ECHOLOCATION IN DOLPHINS WITH A DOLPHIN-BAT COMPARISON

ABSTRACT

Dolphins possess a highly sophisticated auditory system and a keen capability for echolocation. Signals are emitted in the form of high intensity, short duration, broadband exponentially decaying pulses. The frequency spectra of echolocation signals used by many dolphins are dependent on the output intensity of the signals and not on any fine tuning by the animals. When the output intensity is low, the center frequency of the click tends to be low. As the output intensity increases, the center frequency also tends to increase. The pulses propagate from the dolphin's melon in a relatively narrow beam, and echoes are received via the lower jaw, with a slightly wider beam. Echo- locating dolphins can detect targets at ranges of approximately 100 plus meters, depending on the size of the targets. Target discrimination experiments have shown that dolphins can discriminate the shape, size, material composition and internal structure of targets from the echoes. The broadband short duration properties of the signal allow the echoes to have high temporal resolution, so that within the structure of the echoes a considerable amount of information on the properties of the target can be conveyed. A brief comparison between the bat and dolphin sonar system will also be made. Bats typically emit much longer signals and a wider variety of different types of signals than dolphins. Signals used by some bats are suited to detecting Doppler shift, whereas the dolphin signal is designed to be tolerant of Doppler effects.     

Cycle-triggered averaging of respiration-related neuronal activity

A computer system is presented which provides off-line computation of cycle-triggered histograms (CTH) of respiration-related neuronal activity. Binwidths of the histograms are freely selectable by software from 10 ms to 100 ms. For special evaluation purposes, CTHs can be standardized in different ways concerning cycle duration as well as amplitude. Time incidence of maximum frequency, center of gravity and expiration-to-inspiration phase transition within the respiratory cycle are computed. The system employs special hardware interfaces to an 8-bit microcomputer which are briefly described. Data acquisition, data manipulation and output handling of the results are performed by chaining 3 compiled BASIC programs. Some comments on peculiarities of the BASIC language concerning combined application of a BASIC interpreter and a BASIC compiler are brought up. The usefulness of the method is demonstrated by examples of CTHs computed from the activity of medullary respiration-related neurons as well as of the corresponding phrenic nerve mass activity.     

The response of GS-NS0 myeloma cells to single and multiple pH perturbations

Animal cells are cultured in several types of vessels at laboratory and industrial scale the most common being the stirred tank and the air-lift. Economically, it is preferable to culture animal cells at the largest possible scale but the perceived sensitivity of animal cells to hydrodynamic shear has, until now, limited the aeration and agitation rates used. This has been reported to cause inhomogeneities in operational parameters such as dissolved oxygen concentration, temperature and pH. pH is of special interest during the latter stages of many animal cell fermentation because alkali additions, used for pH control, can cause large local pH perturbations of varying size and duration. The effect of single and multiple pH perturbations on the cell growth of a widely used GS-NS0 mouse myeloma cell line grown in batch culture was investigated. The effect of perturbation amplitude and duration was investigated using a single stirred tank reactor (STR). In the single STR system cells were subjected to one pH 8.0 or 9.0 perturbation ranging in duration from 0-90 minutes. No measurable decrease in viable cell number was seen for pH 8.0 perturbations of any duration whereas pH 9.0 perturbations lasting for 10 minutes caused a 15% decrease in viable cell number. The proportion of viable cells decreased with increasing perturbation time and a 90-minute exposure killed all of the cells. The effect of multiple pH perturbations on GS-NS0 cells was investigated using two connected STR's. More specifically the number of perturbations and the perturbation frequency were investigated. Cells were subjected to between 0 and 100 perturbations at pH 8.0; the time between each perturbation (frequency) was 6 minutes and each perturbation lasted for 200 seconds. Viable cell number decreased with increasing perturbation number, with 100 perturbations causing death of 27.5% of cells. Cells were also exposed to 10 perturbations at pH 9.0, each of 200 second duration at frequencies of either 6, 18 or 60 minutes. Approximately 8 times more cells were killed with perturbations at a 6-minute frequency (28.3% cell death) than at a 60-minute frequency (3.4% cell death).     

乌苏里蝈螽和优雅蝈螽雄性鸣声结构的比较研究

应用计算机技术分析了内蒙古草原乌苏里蝈螽Gampsocleis ussuriensis和优雅蝈螽Gampsocleis gratiosa2种螽斯雄性的鸣声结构。乌苏里蝈螽鸣声较复杂,一次鸣叫持续时间6~27s(平均12.5s),每个脉冲组由两类脉冲组组分构成,第1类脉冲组组分为振幅较大的脉冲组,脉冲组持续时间0.0065s,由6~8个脉冲串组成,每个脉冲串持续时间为0.00047s,间隔时间为0.00027s,每个脉冲串含5~10个单脉冲,脉冲串持续时间、间隔时间较短;第2类脉冲组组分为振幅较小的脉冲组,脉冲组持续时间0.0191s,约含有15个左右脉冲串,持续时间为0.00041s,间隔时间约为0.00127s,每个脉冲串含有3~5个单脉冲,脉冲串持续时间、间隔时间也较短,主能峰频率为7.98kHz。优雅蝈螽鸣声则较规则,一次鸣叫持续时间4~232s(平均41.7s)。每个脉冲组也由两类脉冲组组分构成,第1类脉冲组组分振幅较大且逐步增强,脉冲组持续时间0.119s,由10个振幅较大的脉冲串组成,每个脉冲串持续时间为0.00576s,间隔时间为0.005s,每个脉冲串含18~25个单脉冲;第2类脉冲组组分为振幅较小的脉冲组,脉冲组持续时间0.07s,约含有25个左右脉冲串,脉冲串振幅较小,含有6~9个单脉冲,主能峰频率为6.87kHz,次能峰频率为3.25kHz。结果表明乌苏里蝈螽与优雅蝈螽雄性鸣声既有相似的共同特征,同时存在较显著差异。     

Economic and strategic perspectives on investing in RMS and FMS

The evolution of manufacturing systems, according to changing internal and external conditions, requires design and assessment techniques that consider both strategic and financial criteria to evaluate the suitability of the Flexible and Reconfigurable system solutions in addressing these variations. In this paper, a fuzzy multi-objective mixed integer optimization model to evaluate RMS investments used in a multiple product demand environment is presented. The model incorporates in-house production and outsourcing options, machine acquisition and disposal costs, operational costs, and re-configuration cost and duration for the utilized modular machines. The resulting system configurations are optimized for lifecycle costs, responsiveness performance, and system structural complexity simultaneously. A complexity metric that incorporates the quantity of information using an entropy approach is used to represent the inherent structural complexity of the considered system configurations. It accounts for the complexity of the machine modules in a manufacturing system through the use of an index derived from a newly developed manufacturing systems classification code, which captures the effect machine types and technologies on the system’s structural complexity. A metric is proposed to measure the responsiveness ability and efficiency as well as the overall capability of each machine and effectiveness of machines changeover. The application of the developed planning and assessment model that incorporates these three criteria is illustrated with a case study where FMS and RMS alternatives were compared. The suitable conditions for investing in RMS are also discussed.     

Spectral analysis of electroencephalographic recordings of long duration by means of band-pass filters

A method is proposed for spectral analysis of EEG recordings of long duration, using a set of band-pass filters. The sensitivity of the filters varies continuously over their full range, and the input signal is sampled at every sensitivity level. The full spectrum is presented as an array of numbers where the columns are the frequencies and the rows the sensitivity levels, printed as a percentage of the total possible responses of the filter (percent of activity). The logarithm of the numbers expressing the activity of a filter are used for the calculation of the regression line. Thus, the activity in each frequency is characterized by two parameters, the slope and the ordinate at origin, the slope being the more interesting one.     

Surface waves and space charge layers in a spatially inhomogeneous plasma

A theory of surface waves in a layer of a spatially inhomogeneous cold electron plasma is presented. Four types of surface waves are revealed, and the conditions under which they can exist are determined. Complex frequency spectra are obtained, and the mechanisms for wave damping by plasma inhomogeneity are discussed.     

Extended Kalman Filtering technique for the on-line control of OKT3 hybridoma cultures

Summary Extended Kalman Filter (EKF) is used for the on-line estimation of viable cell and monoclonal antibody (MAb) concentrations during batch and fed batch cultures of the OKT3 hybridoma cell line. A kinetic model and an experimental system are presented. The practicability of EKF is demonstrated under both cultivation modes using glucose and ammonia as observation variables. For the same process duration, the concentration of viable cells and antibodies are twice as high in the fed batch as in the batch culture.     

Kinetics of spermatogenesis in megachiropteran bat, Rousettus leschenaulti (Desmarset): seminiferous epithelial cycle, frequency of stages, spermatogonial renewal and germ cell degeneration.

The paper describes in detail the cytomorphology of different types of germ cells, the 10 typical cellular associations or stages of the cycle of seminiferous epithelium (CSE), frequency of appearance of these stages, pattern of spermatogonial stem cell renewal and per cent degeneration of various germ cells in R. leschenaulti. Of the 14 steps of spermiogenesis (stained with PAS-haematoxylin) the first 10 were associated with the stages I-X, whereas, the remaining were found in association with one of the first six stages. The frequency of appearance of the various stages ranged from 3.84% (stage V) to 19.84% (stage I). These observations indicate that stage V is of shortest duration and stage I is of the longest duration in the bat. Five types of spermatogonia (A1, A2, A3, In and B) were identified based on their shape, size and nuclear morphology. Type A spermatogonia are oval with a large nucleus containing 1 or 2 nucleoli. The chromatin showed progressive condensation from A1 to A3 so that the latter appeared darkest among all the A type spermatogonia. The In type derived from A3 are smaller but appear darker than A3 due to heterochromatin crusts along the inner border of the nucleus. The B type spermatogonia derived from In are round and possess single nucleolus. The B type spermatogonia divided mitotically before entering meiosis or the actual production of the primary spermatocytes. The various spermatogonia divided mitotically at fixed stages of the cycle giving rise to their next generations.(ABSTRACT TRUNCATED AT 250 WORDS)     

Duration and frequency of every day activities in total hip patients.

Little knowledge about frequency and duration of daily activities in patients after total hip arthroplasty is available. Such information is required for the definition of realistic load collectives for pre-clinical testing of prostheses. It could also be helpful for the quantitative evaluation of surgery outcome with different prosthesis types. The purpose of this study was to develop and apply a system for the determination of frequency and duration of patient activities in their habitual environment and to compare the results to a clinical outcome score (Harris hip score).A portable activity monitoring system (weight 1.6 kg including batteries) was designed using a Palm top computer, 2 inclination sensors for the thigh and calf and one goniometer positioned at the knee joint. An algorithm was developed to identify frequency and duration of the activities lying, sitting, standing, walking and stair climbing from the signals of the 3 sensors. 42 patients participated in the study and were equipped with the system in the morning at their home. Datasets of 31 patients (age 62.5+/-11.5 y) covered more than 6h (9.8 +/- 1.6 h) and were included in the analysis. Prosthesis specific data as well as the Harris hip score were collected.The most frequent patient activity was sitting (44.3% of the time), followed by standing (24.5%), walking (10.2%), lying (5.8%) and stair climbing (0.4%). The median number of steps/stairs was 6048/164. The number of step cycles representing one year in vivo use should, consequently, be increased to 1.1 million. The Harris hip score (91.4 +/- 9.8) correlated significantly with the number of stairs (r(2) = 0.26, p = 0.003) and showed a positive tendency with the number of steps per day. No differences in activity levels between prosthesis specific factors were found.     

基于最大锋电位间隔的爆发检测自适应算法

在各种类型的培养神经元网络、哺乳动物中枢神经系统和切片中,都可以观察到爆发。爆发是空间-时间放电模式的重要特征,它由一系列高频率发放的连续动作电位组成,由于在时间尺度上的复杂性,使其辨识和探测存在许多困难。自适应算法利用爆发外部锋电位间隔超过爆发内部锋电位间隔的累加和识别爆发本身。基于该算法原理,以爆发内部最大锋电位间隔参数作为确定爆发的约束条件,改进爆发检测自适应算法。实验结果表明,改进算法可以有效地避免爆发的漏检和错检,较准确地检测出神经元的爆发活动,确定爆发活动的数目和持续时间等,爆发检测的平均准确率为93.8%,比原自适应算法提高了35.3%。     

四川山鹧鸪繁殖期的鸣声行为特征

2005年4—12月在四川老君山自然保护区,通过计算机声谱分析技术,对四川山鹧鸪(Arborophilarufipectus)雄性的鸣声行为特征进行了研究,其结果表明,雄性单音节鸣声出现在啼叫、保护领域和求偶中,这些鸣声持续时间差异明显,主峰值差异不明显;雄性双音节鸣声出现在啼叫、保护领域、竞争雌体和求偶中,这些鸣声第一音节时间、第二音节时间、音节间隔时间和主峰值差异极显著,全句时间差异不明显;雄性多音节鸣声出现在保护领域、警戒和惊吓中。雄性亚成体多音节鸣声出现在惊吓和警戒中;雄性成体和亚成体警戒鸣叫的音节持续时间、音节间隔时间和主峰值差异均不明显,全句持续时间差异明显;雄性亚成体和雄性成体的惊吓鸣叫音节持续时间、音节间隔时间、全句持续时间和主峰值差异均不明显。四川山鹧鸪表现出的各种鸣声行为是为了保护配偶和防止天敌,使该种群更好地繁衍。     

A high-speed,quasi-isocratic high-pressure liquid chromatography system for protein sequence analysis

A simple, of less than 20 min duration, quasi-isocratic high-pressure liquid chromatographic system designed for effective analysis of phenylthiohydantoin-amino acids derived from Edman sequencing is described. A second 30-min quasi-isocratic system is presented which may be used when sequenced samples contain extraneous 254 nm-absorbing material. Conditions affecting chromatogram reproducibility are also examined.     

Qualitative behavior of a selectively neutral allelic model

A model of Fleming and Viot for describing frequency distributions for selectively neutral allelic populations and for multidimensional numerical genetic traits is studied, with specific attention given to two qualitative aspects that are derived: the coherence of the random wandering distribution and the tendency to cluster at microscopic scales. A new quantity, called the clustering or occupation index, is introduced to measure relative patchiness of the distribution in terms of a limiting subcell occupation frequency. Results of one- and two-dimensional computer-generated simulations are presented which provide an estimate of the theoretical expected distribution of allelic types. Evidence of the robustness of the model, in the sense that it arises from a variety of assumptions about the reproductive mechanism, is presented in the Appendix.