Internal Coincidence Research Articles

Threatened chronotopes: can chronobiology help endangered species?

Pittendrigh and Daan's 1976 article "Pacemaker structure: A clock for all seasons" marks the foundation of modern seasonal chronobiology. It proposed the internal coincidence model comprised of a Morning (M) and Evening (E) oscillator, which are coupled but synchronized separately by dawn and dusk. It has become an attractive model to explain the seasonal adaptation of circadian rhythms. Using the example of the European hamster, this article connects the classical entrainment concept to species decline and, ultimately, conservation concepts. Seasonality of this species is well studied and circannual rhythms have been described in at least 32 parameters. The European hamster is listed as critically endangered on the International Union for Conservation of Nature (IUCN) red list. Changes in the temporal structure of the environment (the chronotope) caused by climate change and light pollution might be responsible for the global decline. The article shows that classical chronobiological concepts such as the internal coincidence model (Pittendrigh and Daan Pittendrigh and Daan, J Comp Physiol [a] 106:333-355, 1976) are helpful to understand the (chronobiological) causes of the decline and can potentially support species conservation. Knowing the species' physiological limitations as well as its adaptation capacities can potentially prevent its extinction at a time when classical conservation concepts have reached their limits.

Time measurement in insect photoperiodism: external and internal coincidence

The identity and nature of the photoperiodic photoreceptors are now quite well known, as is the nature of the endocrine regulation of the resulting diapauses. The central problem of time measurement—how the photoperiodic clock differentiates long from short days—however, is still obscure, known only from whole-animal experiments and abstract models, although it is clearly a function of the insect circadian system. This review describes some of these experiments in terms of oscillator entrainment and two widely applicable photoperiodic clock models, external and internal coincidence, mainly using data from experiments on flesh flies (Sarcophaga spp) and the parasitic wasp, Nasonia vitripennis.

Error Analysis and Filtering Methods for Absolute Ocean Gravity Data

The atomic gravimeter has advantages of high accuracy and long-term stability, which is suitable for high-resolution absolute sea-surface and deep-sea gravity measurements. The absolute gravity data measured by the atomic gravimeter are affected by rough sea conditions, with significant non-smooth and non-linear noise signals, which reduce the accuracy of gravity measurements. To eliminate the noises in measured gravity data, this paper analyzed the noise sources and innovatively introduced the Variational Modal Decomposition algorithm according to the noise characteristics. Since the filtering result of Variational Modal Decomposition algorithm is limited by the selection of parameters like modal number K and penalty factor α, a Particle Swarm Optimization algorithm and envelope entropy were introduced to adaptively determine the parameters K and α, obtaining the optimal decomposition solution. To verify the reliability of the method, we processed the ocean gravity data, which were dynamically measured by atomic gravimeter (ZAG-M), by using the Empirical Mode Decomposition algorithm, the Complete Ensemble EMD with Adaptive Noise algorithm, and the PSO-VMD algorithm, respectively. The evaluated external coincidence accuracy acquired by comparing the ZAG-M with the ocean relative gravimeter (KSS-32) deployed on the same ship are 0. 71 mGal, 0.54 mGal and 0.48 mGal, respectively, confirming that the PSO-VMD filtering algorithm has a better filtering performance. Finally, the PSO-VMD was applied to all the lines of this ocean measurement experiment with an internal coincidence accuracy of 0.62mGal, verifying the stability of the ZAG-M atomic absolute gravimeter in ocean dynamic measurements and the effectiveness of the proposed algorithm.

The Effectiveness of Life Skills Training on Assertiveness and Work Engagement among Staff of Shemiranat Welfare Vocational Centers

The aim of this semi-experimental study based on the pre-post-test method was to discuss the effectiveness of life skills training on assertiveness and work engagement among personnel of Dr. Shariati vocational and rehabilitation center of Tehran. The statistical population consisted of all staff working (18 people) in 2018. Gambriel and Richi (1975) and Selano and Shufili questionnaires (2001) were used to estimate assertiveness and work engagement. The internal coincidence of instruments was 0.88 and 0.95. In total, 60 educational programs were considered as experimental interventions pertaining to life decuple skills (6 hours training for each skill). In order to test the hypothesis, t correlative groups were used. The results showed that experimental intervention influences on the increment of the assertiveness and its subscales (controversial and fundamental) and general work engagement had a negative impact on the attraction and power by interval 95% (p<0/05).

Ship-borne dynamic absolute gravity measurement based on cold atom gravimeter

Cold atom gravimeter is gradually developing towards miniaturization, dynamics and practicality. It is of great significance to apply it to deep and far sea absolute gravity measurement and underwater long navigation time and high-precision navigation. At present, most cold atom gravimeters are still in the state of laboratory static base or quasi-static base measurement, which is difficult to meet the gravity measurement needs in dynamic application scenarios. Therefore, the research on "static to dynamic" of cold atom interferometric gravity measurement is very urgent and key. In this paper, the basic principle of dynamic measurement is analyzed, the basic method of combined measurement of cold atom gravimeter and accelerometer is given, a set of absolute dynamic gravity measurement system based on cold atom gravimeter and inertial stabilization platform is built, and the ship-borne dynamic measurement experiment is carried out by using the combined measurement method of cold atom gravimeter and traditional accelerometer. Firstly, the continuous absolute gravity measurement for about 40 h is carried out in the laboratory static environment to preliminarily evaluate the performance of the cold atom gravimeter. The sensitivity is 447 µGal/<inline-formula><tex-math id="M2">\begin{document}$\sqrt {{\text{Hz}}} $\end{document}</tex-math><alternatives><graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="11-20220113_M2.jpg"/><graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="11-20220113_M2.png"/></alternatives></inline-formula>, and the long-term stability can reach 2.7 µgal. On this basis, the ship-borne experiment is conducted, the survey ship sails on the lake at a speed of about 4.6 kn, and the ship-borne absolute dynamic gravity measurement is carried out by means of repeated survey lines. After evaluation, the internal coincidence accuracy of the four repeated survey lines is 2.272 mGal, and the external coincidence accuracy values of the four voyages are 2.331, 1.837, 3.988 and 2.589 mGal respectively. Finally, according to the experimental results, the possible problems are further analyzed and summarized. This experimental study provides preliminary verification and technical scheme reference for marine absolute dynamic gravity measurement.

A New Method for Determining the Gravity Disturbance Vector in Strapdown Airborne Gravimetry

A two-step method for determining the gravity disturbance vector based on strapdown airborne gravimeter (SAG) and Global navigation satellite system (GNSS) is proposed. First, a strapdown navigation algorithm and a Kalman filter are used to estimate and compensate for the biases of the accelerometers by the maneuvering flight of SAG. Second, the gravity disturbance vector equations of SAG are established, and the forward and smoothing Kalman filter tuned by the formula of the gravity parameter in the Markov stochastic process are used to estimate the gravity disturbance vector, the model of which is described by the second-order Markov stochastic process to separated it from the biases of the accelerometers. The validity of the above method is verified by processing the data of the repeated line flight test of SAG in the South China Sea, and the results reveal that the internal coincidence accuracy of gravity anomaly is better than 0.4 mGal, and that of the horizontal gravity disturbance is better than 2 mGal.

Analysis of spatiotemporal characteristics of internal coincidence accuracy in global TEC grid data

Evaluating the coincidence accuracy and time-varying characteristics of global total electron content (TEC) grid data can contribute to the improvement of the performance of global ionosphere maps (GIMs) and provide effective data support and theoretical verification for GIMs model update. This paper applies the global TEC grid data and GPS single-station ionospheric TEC data published by IGS from 1999 to 2020, as well as the F10.7 and SSN data series provided by the World Sunspot Index Data Center in Belgium. Using correlation, time series, and contour chart analyses, the correlation between TEC RMS and F10.7, SSN, and the accuracy-compliant space–time variation characteristics in the global TEC grid data are studied and analyzed. The results show the accuracy of the global TEC grid data is highly correlated with the solar activity intensity. The mean values of the correlation coefficients R between TEC RMS and F10.7, SSN are 0.755 and 0.707, respectively. The internal coincidence accuracy of single station GPS-TEC and global grid TEC is better than 3 TECU and is closely related to the solar activity. Globally, TEC RMS in land and ocean areas have significant differences. In general, the accuracy of the northern hemisphere is significantly higher than that of the southern hemisphere, and the accuracy of land is higher than that of the ocean. Among them, the accuracy of Europe and North America is the highest, the precision of the Pacific region is obviously on the low side, and “double hump” phenomenon can be observed. The accuracy of the global TEC grid data is closely related to the number of stations and satellites. The accuracy of the TEC grid data is higher in areas where the number of stations is dense, or when there are more satellites.

Microdeformation monitoring by permanent scatterer GB-SAR interferometry based on image subset series with short temporal baselines: The Geheyan Dam case study

Deformation measurement precision of ground-based synthetic aperture radar (GB-SAR) is significantly limited by atmospheric disturbances. To separate the atmospheric and time domain low-pass deformations in high-time-sampling-rate image sequences, an improved permanent scatterer (PS) GB-SAR interferometry method is proposed to monitor microdeformation. The interferometric analysis is based on PSs and image subset series with short temporal baselines. A polynomial atmospheric correction method is adopted to remove the main atmospheric phase of the interferograms and adjust the interferometric phase model accordingly. The linear deformation rates are estimated by a quasi-stable adjustment method guaranteeing the internal coincidence accuracy of the estimation. Spatiotemporal filtering is implemented on the residual phase to obtain the remaining nonlinear deformation to complete the deformation sequence. An experiment was conducted on the Geheyan Dam, China, verifying the GB-SAR results with plummet data. The RMSEs calculated between the deformation series by the two methods were better than 0.30 mm.

Deformation Detection Method of Mine Tunnel Based on Mobile Detection System.

Subway structure safety detection is an important method to ensure the safe operation of trains. Efficient, high-precision, and automatic tunnel clearance detection is the key to ensure safe operations. This study introduces a mobile tunnel scanning system that integrates a scanner, an inertial measurement unit (IMU), and a rail car. Global Navigation Satellite System (GNSS) time and system hardware calibration are used to synchronize time and space information of the system; the attitude and speed are corrected using the control points from the tunnel to improve the accuracy of absolute positioning. The section coordinate system is converted using the control points and system calibration parameters to complete the tunnel clearance inspection, and the distance between the nearest point of the section and the clear height of the vault is given. Taking Fengxi Road’s Bashan tunnel section of Chongqing Metro Line 5 as an example, the overall system accuracy was tested. The accuracy of chord line measurements was within 1 mm, the internal coincidence accuracy of repeated measurements of the vault clear height was 1.1 mm, the internal coincidence accuracy of repeated measurements of the closest gauge point was 4.8 mm, and the system calibration accuracy was approximately 2 mm. Compared with the existing scheme, the system combines absolute measurement and relative measurement mode to judge the structural safety of tunnel section from multiple angles, high precision, and high efficiency.

Research on a Precision and Accuracy Estimation Method for Close-Range Photogrammetry

Precision and accuracy estimation is an important index used to reflect the measurement performance and quality of a measurement system. To reveal the significance and connotations of the precision and accuracy estimation index of a close-range photogrammetry system, several common precision and accuracy estimation methods are proposed. They are explained from a theoretical perspective, and the mechanism of the internal coincidence precision estimation and the external coincidence accuracy estimation are deduced, respectively. Through detailed experimental design and testing, the validity and reliability of the proposed precision and accuracy estimation methods are verified, which provides strong evidence for the quality control, optimization and evaluation of the measurement results from a close-range photogrammetry system. At the same time, it has significance for the further development of precision and accuracy estimation analysis of close-range photogrammetry systems.

The temporal ‘structure’ and function of the insect photoperiodic clock: a tribute to Colin S. Pittendrigh

AbstractIn 1936, Erwin Bünning suggested that photoperiodic time measurement was a function of the circadian system. Colin Pittendrigh became an ardent supporter of Bünning's hypothesis, drawing parallels between photoperiodism and his own group's investigations of adult eclosion rhythmicity in the fruit fly Drosophila pseudoobscura. They developed several more modern versions of Bünning's general hypothesis based on the entrainment of circadian oscillations to the light cycle, including ‘external coincidence’, which is a derivation of Bünning's original model, and ‘internal coincidence’, which relied upon seasonal changes in the mutual phase relationship of oscillators within a multi‐oscillator circadian system. This review considers the experimental evidence for the central role of the circadian system in photoperiodic timing and, in some species, for both external and internal coincidence. Pittendrigh, however, pursued the idea of internal coincidence further with his analysis of the pacemaker–slave organization of eclosion rhythmicity in D. pseudoobscura and proposed a similar theoretical model for photoperiodism comprising a group of slave oscillators driven by a light‐sensitive pacemaker. In this model, the phase relationships of the slaves to the pacemaker were affected by (i) the relative periods of the pacemaker and slave(s); (ii) the strength(s) of the coupling between the two; and (iii) the dampening coefficients of the various slaves. Manipulation of these variables showed that the slaves adopted different internal phase relationships (both to each other and to the pacemaker) under the influence of changes in daily photophase, the period of the Zeitgeber and phase shifts of the entraining light cycle.

Phylogeny and oscillating expression of period and cryptochrome in short and long photoperiods suggest a conserved function in Nasonia vitripennis

Photoperiodism, the ability to respond to seasonal varying day length with suitable life history changes, is a common trait in organisms that live in temperate regions. In most studied organisms, the circadian system appears to be the basis for photoperiodic time measurement. In insects this is still controversial: while some data indicate that the circadian system is causally involved in photoperiodism, others suggest that it may have a marginal or indirect role. Resonance experiments in the parasitic wasp Nasonia vitripennis have revealed a circadian component in photoperiodic time measurement compatible with a mechanism of internal coincidence where a two components oscillator system obtains information from dawn and dusk, respectively. The identity of this oscillator (or oscillators) is still unclear but possible candidates are the oscillating molecules of the auto-regulatory feedback loops in the heart of the circadian system. Here, we show for the first time the circadian oscillation of period and cryptochrome mRNAs in the heads of Nasonia females kept under short and long photoperiods. Period and cryptochrome mRNA levels display a synchronous oscillation in all conditions tested and persist, albeit with reduced amplitude, during the first day in constant light as well as constant darkness. More importantly, the signal for the period and cryptochrome oscillations is set by the light-on signal. These results, together with phylogenetic analyses, indicate that Nasonia’s period and cryptochrome display characteristics of homologous genes in other hymenopteran species.

Application of Artificial Neural Network in GPS Height Transformation

GPS technology has been widely used since it was put into use. At present, the plane locational accuracy of GPS can already achieve millimeter level. But in terms of height, in order to apply the GPS ellipsoidal height in engineering practice, the geoid seperation or height anomaly of the corresponding point must be achieved to transform GPS geodetic height to normal height. In this paper, by taking 12 points from the national GPS control network of Xuxiang Village of Haining City as sample data, a BP neural network using 3-4-2-1 model structure is adopted and a nonlinear coefficient 1.1 is added in the response function. The height anomalies of the 5 points of the test set are calculated and the residual errors are achieved by comparing with the measured values. The internal and external coincidence accuracies of the model are 0.824cm and 0.922cm separately. The result shows that the model can completely meet the precision requirement of the fourth-grade leveling survey and can be used to transform the heights of the study area.

Insect photoperiodism: effects of temperature on the induction of insect diapause and diverse roles for the circadian system in the photoperiodic response

AbstractThis review considers the effects of temperature on insect diapause induction and the photoperiodic response, and includes constant temperature, temperature cycles, pulses and steps in daily light–dark cycles, constant darkness and in constant light, all with reference to various circadian‐based “clock” models. Although it is a comparative survey, it concentrates on two species, the flesh fly Sarcophaga argyrostoma and its pupal parasite Nasonia vitripennis, which possess radically different photoperiodic mechanisms, although both are based upon the circadian system. Particular attention is given to the effects of daily thermoperiod in darkness and to low and high temperature pulses in conjunction with a daily light–dark cycle, treatments that suggest that S. argyrostoma “measures” night length with a “clock” of the external coincidence type. However, N. vitripennis responds to seasonal changes in photoperiod with an internal coincidence device involving both “dawn” and “dusk” oscillators. Other species may show properties of both external and internal coincidence. Although the precepts of external coincidence have been well formulated and supported experimentally, those for internal coincidence remain obscure.

Influence of temporal relationships between serotonergic and dopaminergic precursors on the regulation of gonadal development in birds

This article is focused on the effect of specific phase relation of serotonergic and dopaminergic oscillations on the gonadal responses of different avian species. These species include (i) summer breeding birds – Red headed bunting (exhibiting post-reproductive absolute photorefractoriness) and Indian Weaver bird (which lacks absolute photorefractoriness), (ii) autumn breeding – Spotted munia and Lal munia (photoperiodic responses of which are distinctly different from that of any long day birds described thus far) and (iii) domesticated Japanese quail (which under natural day length breeds in summer, exhibits relative photorefractoriness, but breeds continuously if maintained in long photoperiod).Previous experiments have shown that daily administration of serotonin precursor 5-hydroxytryptophan and dopamine precursor L-dihydroxyphenylalanine given 8h apart during progressive phase of gonadal cycle can lead to a significant decrease in gonadal activity. However, if given at an interval of 12h it leads to an increase in gonadal activity and the effect of other intervals (0-, 4-, 16- and 20-h) were not different from control. Similar effects were observed during regressive phase of the gonadal cycle of above species except in those which display absolute photorefractory phase in their breeding cycle. This shows that, gonad of such species not only develop post-reproductive photorefractoriness but also becomes insensitive to the stimulatory effects of 5-HTP and L-DOPA when given at the interval of 12h. It is suggested that, temporal phase relation of circadian serotonergic and dopaminergic oscillations is the basis of seasonality in birds and may alter the activity of neuroendocrine-gonadal axis not only under natural day length but also under experimental/different photoperiodic conditions. These results are in agreement with the internal coincidence model of photoperiodic time measurement and indicate that birds can detect specific phase relationship between the two neural oscillations for their reproductive regulations and circadian organization is intricately involved in the regulation of seasonality.

Solar rhythm in the regulation of photoperiodic flowering of long-day and short-day plants

In photoperiodic flowering, long-day (LD) plants are induced to flower seasonally when the daylight hours are long, whereas flowering in short-day (SD) plants is promoted under short photoperiods. According to the widely accepted external coincidence model, flowering occurs in LD Arabidopsis when the circadian rhythm of the gene CONSTANS (CO) peaks in the afternoon, when it is light during long days but dark when the days are short. Nevertheless, extending this explanation to SD flowering in rice, Oriza sativa, requires LD and SD plants to have 'opposite light requirements' as the CO orthologue in rice, HEADING-DATE1 (Hd1), promotes flowering only under short photoperiods. This report proposes a role of the plant's solar rhythm in promoting seasonal flowering. The interaction between rhythmic genes entrained to the solar clock and those entrained to the circadian clock form the basis of an internal coincidence model that explains both LD and SD flowering equally well. The model invokes no presumption of opposite light requirements between LD and SD plants, and further argues against any specific requirement of either light or darkness for SD flowering. Internal coincidence predicts the inhibition of SD flowering of the rice plant by a night break (a brief interruption of light), while it also provides a plausible explanation for how a judiciously timed night break promotes Arabidopsis flowering even on short days. It is the timing of the light transitions (sunrise and sunset) rather than the duration of light or darkness per se that regulates photoperiod-controlled flowering.

Insect photoperiodism: seeing the light

This review examines the spectral sensitivities of photoperiodic responses in insects and mites in relation to circadian‐based models for the photoperiodic clock. It concludes that there are probably a number of different photoreceptors at both the organ and molecular levels. These latter probably fall into two classes: (i) a blue‐light sensitive photoreceptor and (ii) a range of opsins (i.e. opsin proteins conjugated with a vitamin A based pigment) absorbing light at a range of wavelengths. In flesh flies (Sarcophaga spp. and possibly other higher Diptera), which are considered to exemplify the ‘external coincidence’ model, entrainment of the photoperiodic oscillator probably involves a blue‐light photoreceptor of Drosophila‐type CRYPTOCHROME (CRY1) absorbing maximally at approximately 470 nm, whereas opsins absorbing at longer wavelengths may be involved in the photo‐inductive process (diapause/nondiapause regulation) that occurs when dawn light coincides with the photo‐inducible phase. In the parasitic wasp Nasonia vitripennis, on the other hand, a species that lacks CRY1 but expresses the nonphotosensitive ‘mammalian‐type’ CRY2, and is considered to exemplify ‘internal coincidence’, entrainment of the dawn and dusk oscillators may involve opsin‐based photoreceptors absorbing light at longer wavelengths as far as the red end of the spectrum. In the Lepidoptera, which express both CRY1 and CRY2, properties of both external and internal coincidence may be evident. The presence or absence of cry1 in the genome may thus emerge as a key to the photoperiodic mechanism on its light input pathway.

A Morning-Specific Phytohormone Gene Expression Program underlying Rhythmic Plant Growth

Most organisms use daily light/dark cycles as timing cues to control many essential physiological processes. In plants, growth rates of the embryonic stem (hypocotyl) are maximal at different times of day, depending on external photoperiod and the internal circadian clock. However, the interactions between light signaling, the circadian clock, and growth-promoting hormone pathways in growth control remain poorly understood. At the molecular level, such growth rhythms could be attributed to several different layers of time-specific control such as phasing of transcription, signaling, or protein abundance. To determine the transcriptional component associated with the rhythmic control of growth, we applied temporal analysis of the Arabidopsis thaliana seedling transcriptome under multiple growth conditions and mutant backgrounds using DNA microarrays. We show that a group of plant hormone-associated genes are coexpressed at the time of day when hypocotyl growth rate is maximal. This expression correlates with overrepresentation of a cis-acting element (CACATG) in phytohormone gene promoters, which is sufficient to confer the predicted diurnal and circadian expression patterns in vivo. Using circadian clock and light signaling mutants, we show that both internal coincidence of phytohormone signaling capacity and external coincidence with darkness are required to coordinate wild-type growth. From these data, we argue that the circadian clock indirectly controls growth by permissive gating of light-mediated phytohormone transcript levels to the proper time of day. This temporal integration of hormone pathways allows plants to fine tune phytohormone responses for seasonal and shade-appropriate growth regulation.

Photoperiodic flowering occurs under internal and external coincidence

Determining the proper time to flower is important to ensure the reproductive success of plants. The model plant Arabidopsis is able to measure day-length and promotes flowering in long day (LD) conditions. One of the most prominent mechanisms in photoperiodic flowering is the clock-regulated gene expression of CONSTANS (CO) and the stabilization and activation of CO protein by light (regarded as external coincidence). We recently demonstrated that timing of the blue-light dependent formation of FLAVIN-BINDING, KELCH REPEAT, F-BOX 1 (FKF1) and GIGANTEA (GI) protein complex is crucial for regulating the timing of CO gene expression. The expression of FKF1 and GI is clock regulated, and their expression patterns have the same phase in LD (regarded as internal coincidence) but not in short day (SD) conditions, where floral induction is greatly delayed. Hence, timing of the FKF1-GI complex formation is regulated by the coincidence of both external and internal cues. Here, we propose a molecular mechanism for CO regulation by FKF1-GI complex formation.

Assessment of behavioral and emotional problems of preschool children: A comparative analysis of mothers', fathers' and caregivers-teachers' evaluations

Due evaluation of possible emotional disorders in preschool age is important not only from a theoretical point of view, explaining the etiology, the development, and the prognosis of psychopathology, but also from practical positions applying early psychopathologic intervention and prevention programs. In general, in order to evaluate psychological adaptation of young children, it is necessary to collect information from several sources. This research aims to analyse the information about behavioural and emotional difficulties of children collected from three different sources – mother, father, and nurse – using CBCL/1½-5 and CTRF/1½-5 (Achebach and Rescorla, 2000) scales and compare it to each other in order to find out whether the information collected from different sources about the same child is coincident. The results show that internal coincidence of both scales is better of evaluations provided by nurses than parents. The evaluations of mothers and fathers are more coincident than that of nurses and parents. The evaluations of girls are less different and more coincident than boys. Average evaluations of parents under different scales are higher than those of nurses, except concentration difficulties and withdrawal. Summarising the results of the research, the author sets guidelines for possible further research of early child development and discusses possibilities of psychological evaluation of children.