scholarly journals Data-driven modeling of group formation in the fission-fusion dynamics of Bechstein’s bats

2019 ◽  
Author(s):  
Nicolas Perony ◽  
Gerald Kerth ◽  
Frank Schweitzer
Keyword(s):  
Colony Size ◽  
Group Formation ◽  
System Size ◽  
Short Time Scale ◽  
Critical System ◽  
Long Time ◽  
Global Coordination ◽  
Communal Roosting ◽  
One Year ◽  
Data Driven Modeling

AbstractCommunal roosting in Bechstein’s bat colonies is characterized by the formation of several groups that use different day roosts and that regularly dissolve and re-merge (fission-fusion dynamics). Analyzing data from two colonies of different size over many years, we find that (i) the number of days bats stay in the same roost before changing follows an exponential distribution that is independent of the colony size, and (ii) the number and size of groups bats formed for roosting depend on the size of the colony such that above a critical colony size two to six groups of different sizes are formed. To model these two observations, we propose an agent-based model in which agents make their decisions about roosts based on both random and social influences. For the latter, they copy the roost preference of another agent which models the transfer of the respective information. Our model is able to reproduce both the distribution of stay length in the same roost and the emergence of groups of different sizes dependent on the colony size. Moreover, we are able to predict the critical system size at which the formation of different groups emerges without global coordination. We further comment on dynamics that bridge the roosting decisions on short time scale (less than one day) with the social structures observed at long time scales (more than one year).

scholarly journals Bottom-Up Generation of Peak Demand Scenarios in Water Distribution Networks

2020 ◽  
Vol 13 (1) ◽  
pp. 31
Author(s):  
Enrico Creaco ◽  
Giacomo Galuppini ◽  
Alberto Campisano ◽  
Marco Franchini
Keyword(s):  
Water Distribution ◽  
Distribution Networks ◽  
Water Distribution Networks ◽  
Peak Demand ◽  
Long Time ◽  
Cross Correlations ◽  
User Demand ◽  
One Year ◽  
The One ◽  
Best Fit

This paper presents a two-step methodology for the stochastic generation of snapshot peak demand scenarios in water distribution networks (WDNs), each of which is based on a single combination of demand values at WDN nodes. The methodology describes the hourly demand at both nodal and WDN scales through a beta probabilistic model, which is flexible enough to suit both small and large demand aggregations in terms of mean, standard deviation, and skewness. The first step of the methodology enables generating separately the peak demand samples at WDN nodes. Then, in the second step, the nodal demand samples are consistently reordered to build snapshot demand scenarios for the WDN, while respecting the rank cross-correlations at lag 0. The applications concerned the one-year long dataset of about 1000 user demand values from the district of Soccavo, Naples (Italy). Best-fit scaling equations were constructed to express the main statistics of peak demand as a function of the average demand value on a long-time horizon, i.e., one year. The results of applications to four case studies proved the methodology effective and robust for various numbers and sizes of users.

scholarly journals Transoral Endoscopic Adenoidectomy

2009 ◽  
Vol 2009 ◽  
pp. 1-4 ◽  
Author(s):  
Amr El-Badrawy ◽  
Mosaad Abdel-Aziz
Keyword(s):  
High Risk ◽  
Nasal Allergy ◽  
Nasal Endoscope ◽  
Experienced Surgeon ◽  
Nasal Symptoms ◽  
Recent Advancement ◽  
Long Time ◽  
One Year ◽  
Telephone Questionnaire

Objective. Adenoid curette guided by an indirect transoral mirror and a headlight is a simple and quick procedure that has already been in use for a long time, but this method carries a high risk of recurrence unless done by a well-experienced surgeon. The purpose of this paper was to evaluate the efficacy of transoral endoscopic adenoidectomy in relieving the obstructive nasal symptoms.Methods. 300 children underwent transoral endoscopic adenoidectomy using the classic adenoid curette and St Claire Thomson forceps with a Hopkins 4-mm nasal endoscope introduced through the mouth and the view was projected on a monitor. Telephone questionnaire was used to follow-up the children for one year. Flexible nasopharyngoscopy was carried out for children with recurrent obstructive nasal symptoms to detect adenoid rehypertrophy.Results. No cases presented with postoperative complications. Only one case developed recurrent obstructive nasal symptoms due to adenoid regrowth and investigations showed that he had nasal allergy which may be the cause of recurrence.Conclusion. Transoral endoscopic adenoidectomy is the recent advancement of classic curettage adenoidectomy with direct vision of the nasopharynx that enables the surgeon to avoid injury of important structures as Eustachian tube orifices, and also it gives him the chance to completely remove the adenoidal tissues.

Characteristic of morphological traits and biochemical indicators in Linum pubescens

2021 ◽  
pp. 55-64
Keyword(s):  
Eastern Mediterranean ◽  
Plant Genetic Resources ◽  
Natural Populations ◽  
Morphological Characteristics ◽  
Flowering Plant ◽  
Ex Situ ◽  
Bright Pink ◽  
Long Time ◽  
Bright Color ◽  
One Year

The article describes the morphological characteristics and biochemical parameters of a very little studied wild species Linum pubescens (downy flax). This representative of the genus Linum naturally grows in the eastern Mediterranean: Palestine, Syria, Lebanon, Israel, Turkey, Iraq, Greece, Cyprus, Albania. There are brief references to it in the description of the flora of these regions. In Israel, on natural populations of L. pubescens, studies of dimorphic heterostyly, anatomical features of the flower, mechanisms of pollination and incompatibility were carried out. However, other signs, including economically valuable ones, are not described in him. We were the first to study the species ex-situ in a field bank. It was found that in the arid conditions of the southeastern Steppe of Ukraine L. pubescens has a one-year development cycle, a height of 30 cm, 1.2 flowering stems, a bright pink flower with a diameter of 25 mm, a small slightly elongated box with a diameter of 2.7 mm, weight 1000 seeds is 0.6 g, and the leaf area is 218.9 mm2. Plants bloom in mid-July- September. Taking into account the rather large size, the bright color of the flower and the flowering period, we believe that the L. pubescens species has prospects of use as an ornamental flowering plant. In the resulting artificial population of L. pubescens, dimorphic heterostyly is clearly traced. Long and short pest morphs are clearly identified. L. pubescens seeds contain 24% protein and 35% oil. The fatty acid composition of the oil belongs to the "linum-type", like most other types of flax. With a low content of saturated acids (palmitic 6.7% and stearic 2.8%) and a significant predominance of unsaturated acids, especially linolenic up to 64%. It was revealed that this species has a dense non-cracking capsule. This trait is unusual for other flax varieties. Most annual and perennial species are characterized by moderate to severe cracking. Cultivated flax has a non-cracking boll, but not a hard one that breaks easily. It was found that less organic matter and more ash elements accumulate in the capsules and seeds of L. pubescens than in other species of the genus Linum. Probably, this feature, together with non-cracking, helps to better preserve fruits in difficult natural conditions and preserves seed germination for a long time. According to A.A. Zhuchenko, plant genetic resources are divided into six groups. At this stage, L. pubescen is classified as a wild weed relative. It was proposed to include L. pubescens in breeding work to create ornamental varieties in order to transfer it to the improved germplasm group in the future.

scholarly journals Temporal variations in rockfall and rock-wall retreat rates in a deglaciated valley over the past 11 k.y.

Geology ◽  
2020 ◽  
Vol 48 (6) ◽  
pp. 594-598 ◽  
Author(s):  
Solmaz Mohadjer ◽  
Todd A. Ehlers ◽  
Matthias Nettesheim ◽  
Marco B. Ott ◽  
Christoph Glotzbach ◽  
...  
Keyword(s):  
Power Law ◽  
Time Scale ◽  
Temporal Variations ◽  
Climatic Conditions ◽  
Short Time Scale ◽  
Similar Frequency ◽  
Rock Wall ◽  
Significant Difference ◽  
Long Time ◽  
Frequency Magnitude

Abstract This study addresses the temporal variations in rockfall activity in the 5.2 km2 calcareous cliffs of the deglaciated Lauterbrunnen Valley, Switzerland. We did this using 19 campaigns of repeated terrestrial laser scans (TLS) over 5.2 yr, power-law predicted behavior from extrapolation of the TLS-derived frequency-magnitude relationship, and estimates of long-time-scale (∼11 k.y.) activity based on the volume of preserved postglacial rockfall talus. Results from the short-time-scale observations indicate no statistically significant difference between TLS observations averaging over 1.5 versus 5.2 yr. Rock-wall retreat rates in both cases are 0.03–0.08 mm/yr. In contrast, the power-law predicted rock-wall retreat rates are 0.14–0.22 mm/yr, and long-term rates from talus volumes are 0.27–0.38 mm/yr. These results suggest (1) short (1.5 yr) TLS inventories of rockfalls provide (within uncertainties) similar frequency-magnitude relationships as longer (5.2 yr) inventories, thereby suggesting short observation periods may be sufficient for hazard characterization from TLS, and (2) higher rock-wall retreat rates over long time scales (Holocene averaged) may reflect debuttressing and stress relaxation effects after glacial retreat, and/or enhanced rockfall activity under periglacial (climatic) conditions.

scholarly journals Long-wavelength fluctuations and anomalous dynamics in 2-dimensional liquids

2019 ◽  
Vol 116 (46) ◽  
pp. 22977-22982 ◽  
Author(s):  
Yan-Wei Li ◽  
Chandan K. Mishra ◽  
Zhao-Yan Sun ◽  
Kun Zhao ◽  
Thomas G. Mason ◽  
...  
Keyword(s):  
System Size ◽  
Vibrational Amplitude ◽  
Relaxation Dynamics ◽  
Colloidal Systems ◽  
Long Wavelength ◽  
Disordered Solids ◽  
Melting Temperatures ◽  
Long Time ◽  
Liquid Dynamics ◽  
Anomalous Dynamics

In 2-dimensional systems at finite temperature, long-wavelength Mermin–Wagner fluctuations prevent the existence of translational long-range order. Their dynamical signature, which is the divergence of the vibrational amplitude with the system size, also affects disordered solids, and it washes out the transient solid-like response generally exhibited by liquids cooled below their melting temperatures. Through a combined numerical and experimental investigation, here we show that long-wavelength fluctuations are also relevant at high temperature, where the liquid dynamics do not reveal a transient solid-like response. In this regime, these fluctuations induce an unusual but ubiquitous decoupling between long-time diffusion coefficient D and structural relaxation time τ, where D∝τ−κ, with κ>1. Long-wavelength fluctuations have a negligible influence on the relaxation dynamics only at extremely high temperatures in molecular liquids or at extremely low densities in colloidal systems.

scholarly journals Stratified Flows over and around Long Dynamically Tall Mountain Ridges

2019 ◽  
Vol 76 (5) ◽  
pp. 1265-1287 ◽  
Author(s):  
Arjun Jagannathan ◽  
Kraig Winters ◽  
Laurence Armi
Keyword(s):  
Time Scales ◽  
Time Scale ◽  
Stratified Flows ◽  
Half Width ◽  
Short Time Scale ◽  
Late Time ◽  
Low Level ◽  
Long Time ◽  
Flow Splitting ◽  
Short Time

Abstract Uniformly stratified flows approaching long and dynamically tall ridges develop two distinct flow components over disparate time scales. The fluid upstream and below a “blocking level” is stagnant in the limit of an infinite ridge and flows around the sides when the ridge extent is finite. The streamwise half-width of the obstacle at the blocking level arises as a natural inner length scale for the flow, while the excursion time over this half-width is an associated short time scale for the streamwise flow evolution. Over a longer time scale, low-level horizontal flow splitting leads to the establishment of an upstream layerwise potential flow beneath the blocking level. We demonstrate through numerical experiments that for sufficiently long ridges, crest control and streamwise asymmetry are seen on both the short and long time scales. On the short time scale, upstream blocking is established quickly and the flow is well described as a purely infinite-ridge overflow. Over the long time scale associated with flow splitting, low-level flow escapes around the sides, but the overflow continues to be hydraulically controlled and streamwise asymmetric in the neighborhood of the crest. We quantify this late-time overflow by estimating its volumetric transport and then briefly demonstrate how this approach can be extended to predict the overflow across nonuniform ridge shapes.

scholarly journals Seismic and Rainfall Induced Displacements of an Existing Landslide: Findings from the Continuous Monitoring

Geosciences ◽  
2020 ◽  
Vol 10 (3) ◽  
pp. 90 ◽  
Author(s):  
Paolo Ruggeri ◽  
Viviene M. E. Fruzzetti ◽  
Antonio Ferretti ◽  
Giuseppe Scarpelli
Keyword(s):  
Continuous Monitoring ◽  
Average Rate ◽  
Central Italy ◽  
Back Analysis ◽  
Pressure Transducers ◽  
Long Time ◽  
The Difference ◽  
One Year ◽  
National Road

“La Sorbella” is a deep-seated existing landslide in a Miocene clayey formation located in central Italy. Given the interaction with a national road, this landslide has been monitored for a long time with inclinometers and hydraulic piezometers. Recently, the monitoring system was implemented by adding pressure transducers in the Casagrande cells and by equipping the old inclinometers with in-place probes, to allow a remote reading of the instruments and data recording. This system allowed to identify that the very small average rate of movement observed over one year (1.0–1.5 cm/year) is the sum of small single sliding processes, strictly linked to the sequence of rainfall events. Moreover, data recorded by in-place inclinometer probes detected the response of the landslide to the seismic sequence of 2016 occurring in central Italy. Such in situ measurements during earthquakes, indeed rarely available in the scientific literature, allowed an assessment of the critical acceleration of the sliding mass by means of a back-analysis. The possibility to distinguish the difference between seismic and rainfall induced displacements of the slope underlines the potential of continuous monitoring in the diagnosis of landslide mechanisms.

Structural derivative based on inverse Mittag-Leffler function for modeling ultraslow diffusion

2016 ◽  
Vol 19 (5) ◽  
Author(s):  
Wen Chen ◽  
Yingjie Liang ◽  
Xindong Hei
Keyword(s):  
Diffusion Model ◽  
Time Scale ◽  
Structural Function ◽  
Short Time Scale ◽  
Mathematical Tool ◽  
Interacting Particles ◽  
Random System ◽  
Ballistic Motion ◽  
Time Space ◽  
Long Time

AbstractThis paper proposes a novel structural derivative approach to tackle the perplexing modeling problem of ultraslow diffusion. The structural function plays a central role in this new strategy as a kernel transform of underlying time-space fabric of physical systems. Ultraslow diffusion has been observed in numerous lab experiments and field observations, whose behaviors deviate dramatically from the standard anomalous diffusion models characterizing power function of time. The logarithmic diffusion model has since been used to describe bizarre process of ultraslow diffusion but with very limited success. This study applies the inverse Mittag-Leffler function as the structural function in the structural derivative modeling ultraslow diffusion of a random system of two interacting particles. It is observed that the dynamics of two interacting particles are respectively the ballistic motion at the short time scale and the Sinai ultraslow diffusion at the long time scale. Compared with the logarithmic diffusion model, the inverse Mittag-Leffler diffusion model has higher accuracy and manifests clearer physical mechanism. Numerical experiments show that the structural derivative is a feasible mathematical tool to model the ultraslow diffusion using the inverse Mittag-Leffler function as its structural function.

Linear Software Models: Standard Modularity Highlights Residual Coupling

2014 ◽  
Vol 24 (02) ◽  
pp. 183-210 ◽  
Author(s):  
Iaakov Exman
Keyword(s):  
Case Studies ◽  
Design Patterns ◽  
Linear Models ◽  
Formal Theory ◽  
Building Blocks ◽  
System Size ◽  
Software Systems ◽  
Software Models ◽  
Software Modules ◽  
Long Time

Modularity — the decoupling of software units — is essential for composition of real software systems from ready-made components. But for a long time one lacked a formal theory of modularity. Recently we have been developing Linear Software Models as rigorous theoretical modularity standards based upon plain Linear Algebra. By these models, decoupling means just linear independence, within a modularity matrix. This paper applies Linear Software Models to software systems, obtaining three consequences: (1) besides decoupling, various informal notions of software engineering, such as software modules, cohesion, and single responsibility, have for the first time a well-defined formal counterpart; (2) canonical building blocks like Software Design Patterns strictly obey the Linear Software Models; (3) larger software systems obey bordered Linear Models, allowing precise location and visualization of residual coupling. The latter consequences are demonstrated by case studies of software systems from the literature. The applicability of the Linear Software Models is quantitatively shown to scale well with system size, for the given case studies.

On Failure Mechanisms in Flip Chip Assembly—Part 2: Optimal Underfill and Interconnecting Materials

2008 ◽  
Vol 130 (2) ◽  
Author(s):  
Yoonchan Oh ◽  
C. Steve Suh ◽  
Hung-Jue Sue
Keyword(s):  
Time Scale ◽  
Flip Chip ◽  
Thermal Stresses ◽  
Failure Modes ◽  
Scale Effects ◽  
Short Time Scale ◽  
Long Time ◽  
Solder Joint Fatigue ◽  
Scale Properties ◽  
Short Time

The physics explored in this investigation enables short-time scale dynamic phenomenon to be correlated with package failure modes such as solder ball cracking and interlayer debond. It is found that although epoxy-based underfills with nanofillers are shown to be effective in alleviating thermal stresses and improving solder joint fatigue performance in thermal cycling tests of long-time scale, underfill material viscoelasticity is ineffective in attenuating short-time scale propagating shock waves. In addition, the inclusion of Cu interconnecting layers in flip chip area arrays is found to perform significantly better than Al layers in suppressing short-time scale effects. Results reported herein suggest that, if improved flip chip reliability is to be achieved, the compositions of all packaging constituent materials need be formulated to have well-defined short-time scale and long-time scale properties. Chip level circuit design layout also needs be optimized to either discourage or negate short-time wave propagation. The knowledge base established is generally applicable to high performance package configurations of small footprint and high clock speed. The approach along with the numerical procedures developed for the investigation can be a practical tool for realizing better device reliability and thus high manufacturing yield.

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