Short Period Length Research Articles

Contribution of neurons that express fruitless and Clock transcription factors to behavioral rhythms and courtship.

Animals need to integrate information across neuronal networks that direct reproductive behaviors and circadian rhythms. In Drosophila, the master regulatory transcription factors that direct courtship behaviors and circadian rhythms are co-expressed in a small set of neurons. In this study we investigate the role of these neurons in both males and females. We find sex-differences in the number of these fruitless and Clock -expressing neurons ( fru ∩ Clk neurons) that is regulated by male-specific Fru. We assign the fru ∩ Clk neurons to the electron microscopy connectome that provides high resolution structural information. We also discover sex-differences in the number of fru -expressing neurons that are post-synaptic targets of Clk -expressing neurons, with more post-synaptic targets in males. When fru ∩ Clk neurons are activated or silenced, males have a shorter period length. Activation of fru ∩ Clk neurons also changes the rate a courtship behavior is performed. We find that activation and silencing fru ∩ Clk neurons impacts the molecular clock in the sLNv master pacemaker neurons, in a cell-nonautonomous manner. These results reveal how neurons that subserve the two processes, reproduction and circadian rhythms, can impact behavioral outcomes in a sex-specific manner.

On generalized continued fraction expansions of short period length

On generalized continued fraction expansions of short period length

Simulation and experimental study of short-period strong magnetic field undulator

Further reducing the period length will be a very attractive direction for the future development of undulators, and it is one of the effective ways to realize the miniaturization of free-electron laser facilities and obtain short wavelengths. In this paper, a novel planar hybrid permanent magnet undulator is proposed which can obtain a higher peak field with a short period length. The dimensions of the magnet blocks and the poles are numerically optimized for a sample undulator with a period length of 16 mm and a gap of 5 mm. Compared to the conventional hybrid undulator, the effective peak field can be enhanced by about 48%. An eight-period model is built and the result of the magnetic field measurement by a pulsed wire system shows a good consistent with the simulation result.

Standard variable short period microwave-plasma undulator

Microwave-plasma undulator (MPU), as a standard short-period length undulator, is a desirable source of hard X-ray with continuous wide spectrum. In this article, the electron wiggling motion under the effect of transverse electric mode, propagating in cold plasma-filled waveguide, is investigated. The deflection parameter and period length of MPU in counter-propagating and co-propagating modes are calculated. Advantages of MPU over conventional and microwave undulators are investigated. It is shown that MPUs generate higher photon flux with overlapping harmonics compared to conventional standard undulators and cover wider energy range of synchrotron radiation. A rectangular MPU with period length of 2.98 mm and deflection parameter of 2.23 and a circular MPU with period length of 2.99 mm and deflection parameter of 2.23 are introduced. Also, a short variable period MPU, with the period length varying from 2.62 mm to 4.12 mm, and a helical MPU is introduced.

A proposal for distributed humidity sensor based on the induced LPFG in a periodic polymer coated fiber structure

In this paper, a distributed relative humidity (RH) or moisture sensor is proposed. The proposed structure is a single mode telecommunication optical fiber coated by humidity sensitive and insensitive polymers periodically. The polymer coated fiber is surrounded by a high Young’s modulus material such as stainless steel mesh. The swelling of the coated Humidity Sensitive Polymers (HSPs) as a result of moisture absorption induces fiber gratings in the single mode fiber. Depending on the coating period relative to the light wavelength, the induced fiber grating can be Fiber Bragg Grating (FBG) or Long Period Fiber Grating (LPFG). The light reflected by the induced FBG or losses due to the coupled energy to the cladding modes in the induced LPFG can be employed to describe the sensor operation. Since long period length (LPFG) manufacturing is much simpler than short period length (FBG) sensors, this investigation is concentrated on the long period length sensors.

Optimizing management of dairy goat farms through individual animal data interpretation: A case study of smart farming in Spain

Dairy goat production systems in developed countries are experiencing an intensification process in terms of higher farm size, electronic identification, reproductive intensification, genetic selection and milking automation. This new situation generates “big data” susceptible to be used to aid farmers during the decision making process. This case study describes how the farm management can be improved by the use of the “Eskardillo”, a tool with a smart-phone terminal which relies on three principles: i) systematic individual data recording (milking control, productivity, genetic merit, morphology, phylogeny, etc.), ii) big data processing and interpretation and iii) interactive feedback to the farmer to optimize farm management. This study evaluated the effectiveness of the Eskardillo tool by monitoring the productive parameters from 2013 to 2016 in 12 conventional Murciano-Granadina dairy goat farms which implemented the Eskardillo (ESK) in late 2014. Moreover, 12 conventional farms without Eskardillo were also monitored as control farms (CTL). Results demonstrated that ESK farms were able to better monitor the productivity and physiological stage of each animal and Eskardillo allowed selecting animals for breeding, replacement or culling according to each animal's records. As a result, goats from ESK farms decreased their unproductive periods such as the first partum age (−30 days), and the dry period length (−20 days) without negatively affecting milk yield per lactation. This study revealed an acceleration in the milk yield in ESK farms since this innovation was implemented (+26 kg / lactation per year) in comparison to the situation before (+7.3) or in CTL farms (+6.1). Data suggested that this acceleration in milk yield in ESK farms could rely on i) a greater genetic progress as a result of a more knowledgeable selection of high merit goats, ii) the implementation of a more effective culling off strategy based on the production, reproductive and health records from each animal, and iii) the optimization of the conception timing for each animal according to its physiological stage and milk yield prospects to customize lactation length while keeping a short and constant dry period length (2 months). Moreover, this study demonstrated a decrease in the seasonality throughout the year in terms of percentage of animals in milking and milk yield allowing an increment in the production of off-season milk (+17%) since Eskardillo was applied. In conclusion, it was demonstrated that the implementation of the Eskardillo tool can be considered a useful strategy to optimize farm management and to contribute to the sustainable intensification of modern dairy goat farms.

Development of a compact electromagnetic undulator for linac-based coherent THz radiation source in Thailand

A linac-based accelerator system at the Plasma and Beam Physics Research Facility of Chiang Mai University in Thailand can produce relativistic femtosecond electron bunches for generating coherent THz radiation. Originally, this accelerator system was built to produce high peak power THz/FIR radiation via transition radiation technique. To extend the system’s capability in production of higher average power and tunable coherent radiation, a project to add an undulator magnet as a source of coherent THz radiation was started. Construction of a compact 40-period electromagnetic undulator with short period length is in progress. Low electricity consumption, inexpensive materials and uncomplicated fabrication process are aimed. An undulator prototype was designed and built to investigate the magnetic field properties and to estimate the possibility on manufacturing of a future undulator magnet. A computer program RADIA was used to model a three-dimensional undulator prototype based on the fabricated magnet material and dimensions. This prototype has 4.5 periods consisting of 8 main-poles and 2 end-poles for magnetic field correction. The simulated peak magnetic field was 0.1858 T or equivalents to an undulator parameter of 0.98. This led to a calculated undulator radiation wavelength at the first harmonic of 109 μm for electron beam with energy of 10 MeV. This radiation is in the forward direction. After manufacturing, the magnetic field of the undulator prototype was measured and analyzed. The measurement result at an optimal excitation current of 5 A showed that an average period length of 54.8 mm and an average peak magnetic field of 0.1855 T were achieved. The measured undulator parameter was 0.97, which resulted in the undulator radiation wavelength of about 107 μm. A future electromagnetic undulator with 40 periods was designed and will be built based on the study results of this undulator prototype. The estimated angular flux density of the radiation emitted from 40 period undulator magnet is dominated at the first harmonic radiation wavelength of 109 μm, which is equivalent to the radiation frequency of 2.8 THz.

Influence of very short rest period lengths on repeated one maximun repetition bench press performance


 Objective: The purpose of this investigation was to compare different rest period lengths between consecutive one maximum repetition bench press attempts on performance and ratings of perceived exertion.
 
 
 
 Method: Eighteen trained men (27.95 ± 4.25 years; 81.00 ± 9.21 kg; 174.62 ± 3.34 cm; bench press relative strength 1.33 ± 0.11 kg/kg of body mass) participated in three randomly ordered sessions that required two consecutive one maximum repetition bench press attempts with 20, 40, or 60-s rest between attempts.
 Results: The Cochran Q analysis showed no significant differences in the ability to successfully perform a second one maximum repetition attempt with 20, 40, or 60-s rest between attempts (p = 0.882). Specifically, no significant differences were found in the successful completion of the first and second attempts for the 20-s (p = 0.317), 40-s (p = 0.083), and 60-s (p = 0.157) trials, respectively. Briefly, for both 20 and 60-s rest conditions Δ% = 88.88% of subjects successfully performed the second attempt and, for the 40-s protocol, only Δ% = 83.33% completed. For the pre and post-set ratings of perceived exertion, the shorter rest period (20-s) promoted significantly higher values compared to the longer rest periods (pre-set ratings of perceived exertion, p = 0.04; post-set ratings of perceived exertion, p = 0.023).
 Conclusions: The results of this study can be applied to recreationally trained individuals with the intent of generating a time-efficient process for conducting a valid and reliable one maximum repetition bench press assessment.
 
 
 
 

Effect of Superpave Short-Term Aging on Binder and Asphalt Mixture Rheology

This study aimed to evaluate the effect of Superpave short term aging period length and type of additive used in modifying the asphalt binder on the creep behavior of asphalt binder and asphalt mix. Hot-mix asphalt (HMA) specimens were prepared at optimum asphalt content using unmodified asphalt, or asphalt with 4% by weight of SBS or PE. The Universal Testing Machine was used to conduct dynamic creep tests. Tests results indicated that the effect of extending the aging period on creep deformation is highly dependent on type of additive used in preparing the asphalt mix. Extending the aging period more than three hours caused insignificant effect of creep behavior of control asphalt mixes. On the other hand, extending the aging period more than one hour caused insignificant effect of creep behavior of asphalt mixes prepared using SBS additive. While for mixes prepared using PE, the creep deformation continues to decrease as aging period increase.

Magnetic resonance of rubidium atoms passing through a multi-layered transmission magnetic grating

We measured the magnetic resonance of rubidium atoms passing through periodic magnetic fields generated by two types of multi-layered transmission magnetic grating. One of the gratings reported here was assembled by stacking four layers of magnetic films so that the direction of magnetization alternated at each level. The other grating was assembled so that the magnetization at each level was aligned. For both types of grating, the experimental results were in good agreement with our calculations. We studied the feasibility of extending the frequency band of the grating and narrowing its resonance linewidth by performing calculations. For magnetic resonance precision spectroscopy, we conclude that the multi-layered transmission magnetic grating can generate periodic fields with narrower linewidths at higher frequencies when a larger number of layers are assembled at a shorter period length. Moreover, the frequency band of this type of grating can potentially achieve frequencies of up to hundreds of PHz.

The Stretching Method for Vibration‐Based Structural Health Monitoring of Civil Structures

AbstractThis article newly proposes the application of the stretching method, that is used in geophysics for detecting variations in the velocity with which waves propagate in the earth's crust from seismic noise recordings, in the context of vibration‐based Structural Health Monitoring (SHM) of civil structures. The result is a computationally efficient long‐term vibration‐based SHM tool, that follows the current trend of using a very limited number of sensors permanently installed on site to measure operational structural responses for the purpose of damage detection. In the SHM setting, the proposed method aims at a direct identification of small permanent shifts in the natural frequencies of the structure in a changing environment, which is achieved by maximizing the correlation coefficient between a reference waveform, computed in a training reference period in which the structure is assumed to be undamaged, and a stretched version of the same waveform evaluated at the current time. The comparison is performed in the frequency domain and the waveform of interest is obtained from cross‐correlations of the ambient vibration measurements. More specifically, in the case of multiple sensors, the waveform can be either the cross‐power spectral density of the signals recorded by a pair of sensors, or the largest singular value of the spectral matrix of the measurements. It follows that the method can be regarded as an extension of the classic Frequency Domain Decomposition (FDD). A key feature of the proposed stretching method is mitigating the effects of environmental fluctuations by time domain averaging of cross‐correlations over a proper period of time, before taking their Fourier transform to estimate the spectral densities. Such a time domain averaging is carried out in a relatively long period of time for estimating the reference waveform, whereas it is carried out in a shorter time for estimating the current waveform. The main features of the proposed methodology are its very low sensitivity to environmental fluctuations, resulting in a quite short training period length, and its low computational cost, which could be compatible with a direct integration within smart sensors with embedded electronics. The performance of the method is illustrated in the case study of an Italian historical monumental bell tower that has been monitored by the authors for more than 1 year.

Influence of very short rest period lengths on repeated one maximun repetition bench press performance

Abstract Objective The purpose of this investigation was to compare different rest period lengths between consecutive one maximum repetition bench press attempts on performance and ratings of perceived exertion. Method Eighteen trained men (27.95 ± 4.25 years; 81.00 ± 9.21 kg; 174.62 ± 3.34 cm; bench press relative strength 1.33 ± 0.11 kg/kg of body mass) participated in three randomly ordered sessions that required two consecutive one maximum repetition bench press attempts with 20, 40, or 60-s rest between attempts. Results The Cochran Q analysis showed no significant differences in the ability to successfully perform a second one maximum repetition attempt with 20, 40, or 60-s rest between attempts ( p = 0.882). Specifically, no significant differences were found in the successful completion of the first and second attempts for the 20-s ( p = 0.317), 40-s ( p = 0.083), and 60-s ( p = 0.157) trials, respectively. Briefly, for both 20 and 60-s rest conditions Δ% = 88.88% of subjects successfully performed the second attempt and, for the 40-s protocol, only Δ% = 83.33% completed. For the pre and post-set ratings of perceived exertion, the shorter rest period (20-s) promoted significantly higher values compared to the longer rest periods (pre-set ratings of perceived exertion, p = 0.04; post-set ratings of perceived exertion, p = 0.023). Conclusions The results of this study can be applied to recreationally trained individuals with the intent of generating a time-efficient process for conducting a valid and reliable one maximum repetition bench press assessment.

Disorder-induced anomalously signed Hall effect in crystalline GeTe/Sb2Te3 superlattice-like materials

Opposite to the almost persistent p-type conductivity of the crystalline chalcogenides along the GeTe-Sb2Te3 tie line, n-type Hall mobility is observed in crystalline GeTe/Sb2Te3 superlattice-like material (SLL) with a short period length. We suggest that this unusual carrier characteristic originates from the structural disorder introduced by the lattice strain and dangling bonds at the SLL interfaces, which makes the crystalline SLLs behave like the amorphous chalcogenides. Detailed structural disorder in crystalline SLL has been studied by Raman scattering, X-ray photoelectron spectroscopy, as well as Variable-energy positron annihilation spectroscopy measurements. First-principles calculations results show that this structural disorder gives rise to three-site junctions that dominate the charge transport as the period length decreases and result in the anomalously signed Hall effect in the crystalline SLL. Our findings indicate a similar tetrahedral structure in the amorphous and crystalline states of SLLs, which can significantly reduce the entropy difference. Due to the reduced entropy loss and increased resistivity of crystalline phase introduced by disorder, it is not surprising that the SLLs exhibit extremely lower RESET current and power consumption.

Contributions of strain relaxation and interface modes to thermal transport in superlattices

Superlattice structures are widely used in electronic and optoelectronic devices, many of which depend heavily on thermal management for performance and reliability. It has been observed that silicon/germanium superlattices exhibit an enhancement in thermal conductivity at very short period lengths, which has been attributed to the contribution of coherent phonons. Here we investigate additional potential contributions to enhanced thermal conductivity in superlattices as period length is reduced, finding that a reduction in strain relaxation as well as increased contributions of interface modes that have vibrational character intermediate between those of the two constituent materials offer additional mechanisms for increased thermal conductivity.

Agency Models With Frequent Actions

The paper analyzes dynamic principal–agent models with short period lengths. The two main contributions are: (i) an analytic characterization of the values of optimal contracts in the limit as the period length goes to 0, and (ii) the construction of relatively simple (almost) optimal contracts for fixed period lengths. Our setting is flexible and includes the pure hidden action or pure hidden information models as special cases. We show how such details of the underlying information structure affect the optimal provision of incentives and the value of the contracts. The dependence is very tractable and we obtain sharp comparative statics results. The results are derived with a novel method that uses a quadratic approximation of the Pareto boundary of the equilibrium value set.

A Time Driven RCCP Model with Two Levels of Planning and a Reactive Planning Approach for Tactical Project Planning

This paper proposes a mixed-integer linear programming (MILP) time driven RCCP model that handles different planning levels by varying the length of the time periods. The model is based on the continuous time representation of work packages’ start and end events and the discrete time representation of resource constraints. The model considers shorter period lengths at the beginning of the planning horizon to produce a detailed plan, while further periods cover a larger span. The proposed model is compared to a RCCP model with fixed period lengths. Both models were tested on medium-sized project instances. The computational results proved that the proposed model performs considerably better in terms of computational times. A reactive planning approach is also proposed to analyze the performance and robustness of both models. The results analysis showed that reducing resource capacities of aggregated periods by a percentage of 20% allowed us to obtain comparable results for the two models.

Demonstration of inverse free-electron laser seeding in a sub-80 K, short period cryogenic undulator

Short period, high field undulators have been shown to permit operation of x-ray free-electron lasers with short gain-lengths, and at unprecedented short wavelengths. In addition, the reduced beam energy required to reach resonance with a given radiation wavelength in short period undulators could prove useful in advanced inverse free-electron laser (IFEL) seeding schemes for future light sources, such as high-gain harmonic generation and echo-enabled harmonic generation, or in IFEL acceleration. We report here the in situ beam testing of a 9 mm period length cryogenic undulator having undulator parameter near unity in the context appropriate for advanced seeding and acceleration schemes, a linear accelerator. Because of the short period length of the undulator, a 47 MeV high-brightness electron beam could be used to produce near infrared photons via the undulator radiation mechanism. The undulator radiation was observed through a filter and the spectral response of the undulator is compared to simulation. Finally, an 800 nm seed laser was introduced in order to generate an energy modulation via the IFEL mechanism. Resonance between the electron beam and the laser seed was achieved without detailed knowledge of the temperature dependent undulator magnetic field through the observation of the undulator radiation. The energy modulation (and concomitant energy spread increase) of the electron beam was observed both directly in an electron beam spectrometer and indirectly via coherent transition radiation after conversion to a density modulation in a longitudinally dispersive chicane.

P53 regulates Period2 expression and the circadian clock

The mechanistic interconnectivity between circadian regulation and the genotoxic stress response remains poorly understood. Here we show that the expression of Period 2 (Per2), a circadian regulator, is directly regulated by p53 binding to a response element in the Per2 promoter. This p53 response element is evolutionarily conserved and overlaps with the E-Box element critical for BMAL1/CLOCK binding and its transcriptional activation of Per2 expression. Our studies reveal that p53 blocks BMAL1/CLOCK binding to the Per2 promoter leading to repression of Per2 expression. In the suprachiasmatic nucleus (SCN), p53 expression and its binding to the Per2 promoter are under circadian control. Per2 expression in the SCN is altered by p53 deficiency or stabilization of p53 by Nutlin-3. Behaviorally, p53−/− mice have a shorter period length that lacks stability and they exhibit impaired photo-entrainment to a light pulse under a free-running state. Our studies demonstrate that p53 modulates mouse circadian behavior.

Search for Seasonal Rhythmicity of Pineal Melatonin Production in Rats Under Constant Laboratory Conditions: Spectral Chronobiological Analysis, and Relation to Solar and Geomagnetic Variables

Earlier we reported that in a number of experiments pineal melatonin production in rats under constant laboratory conditions displayed seasonal rhythms but subsequently were not always able to confirm this. Since there was no indication under which conditions such rhythms may be present, we performed four consecutive identical experiments with untreated female Sprague–Dawley rats within the same animal room during 1997–2006. Nocturnal urine samples (19–23, 23–3, 3–7 h) were collected at monthly intervals over 494–658 d with 12 animals each in experiments I and II (1997–1999, 1999–2000), 30 animals in experiment III (2002–2004), and 15 in experiment IV (2005–2006). 6-Sulfatoxymelatonin (aMT6s) was measured by ELISA. The excreted aMT6s at each time interval as well as total nocturnal aMT6s-excretion (19–7 h) was submitted to standard statistical analyses as well as to a spectral chronobiological analysis to determine the period lengths of the components involved which was followed by processing with the single cosinor method. Seasonal rhythm components (circannual period length: 360 ± 60 d) were detected in experiment III (2002–2004) for the overall nocturnal excretion as well as for two sub-intervals (23–3 and 3–7 h) and in one night interval of experiment II (23–3 h). Multiple components with mostly short period lengths of around 100 d and some long ones of 500–650 d were found in the other experiments. Systematic MESOR and amplitude variations were observed during the experiments, being highest in experiment II (19–7 h, also 23–3 h and 3–7 h) and lowest in experiments I and IV. These results illustrate that seasonal melatonin rhythms are not a general phenomenon in female laboratory rats indicating an involvement of unknown environmental cues. As an extension of our earlier hypothesis regarding a seasonal Zeitgeber function of the horizontal intensity H of the geomagnetic field showing circannual variations, we assume further modulation by the 11-yrs' sunspot cycle which leads to geomagnetic disturbances and could facilitate seasonal aMT6s rhythmicity during specific years. (Author correspondence: christian.bartsch@uni-tuebingen.de)

Development trends for insertion devices of future synchrotron light sources

The in-vacuum undulator with a permanent magnet at room temperature is a mature technology and is widely used; with a short period length in a medium-energy facility, it can enhance photon brilliance in the hard x-ray region. A cryogenic permanent magnet has been investigated as an in-vacuum undulator; this undulator will become the best prospective device to satisfy the requirements of a photon source with great brilliance in the hard x-ray region. For the further hard x-ray region, a superconducting wiggler can provide great flux with a continuous spectrum, whereas a superconducting undulator will provide great brilliance with a discrete spectrum. High-temperature superconducting wires are highly promising for use in the development of superconducting undulators; unique algorithms for their development with an extremely short period in a small-magnet gap have been devised. Some out-of-vacuum planar undulators with special functions must also be fabricated to enable diverse applications in various light-source facilities. This article describes current and future developments for insertion devices in storage-ring and free-electron-laser facilities and discusses their feasibility for use therein.