Design of Energy Absorbing Metamaterials Using Stochastic Soft-Wall Billiards

Physical principles for designing cellwise artificial materials with energy-absorbing/harvesting and wave guiding properties are discussed in the present work. We analyzed the evolution of waves in a one-dimensional lattice of 3D massive potential wells with light particles inside. The potential wells were coupled with elastic springs and represented soft-wall versions of the so-called stochastic billiards. A billiard could switch from repelling to the stadium type as the parameter of shape changed its sign from positive to negative. We found that certain shapes of the potential wells/containers provided a one-directional trend of the energy flow from the chain of containers into the chaotically moving light inclusions by increasing their total kinetic energy. As a result, propagating waves became trapped by giving rise to standing waves with chaotic mode shapes with decaying amplitudes.

Decoding Rocks: An Assessment of Geomaterial Microstructure Using X-ray Microtomography, Image Analysis and Multivariate Statistics

An understanding of the microstructure of geomaterials such as rocks is fundamental in the evaluation of their functional properties, as well as the decryption of their geological history. We present a semi-automated statistical protocol for a complex 3D characterization of the microstructure of granular materials, including the clustering of grains and a description of their chemical composition, size, shape, and spatial properties with 44 unique parameters. The approach consists of an X-ray microtomographic image processing procedure, followed by measurements using image analysis and statistical multivariate analysis of its results utilizing freeware and widely available software. The statistical approach proposed was tested out on a sandstone sample with hidden and localized deformational microstructures. The grains were clustered into distinctive groups covering different compositional and geometrical features of the sample’s granular framework. The grains are pervasively and evenly distributed within the analysed sample. The spatial arrangement of grains in particular clusters is well organized and shows a directional trend referring to both microstructures. The methodological approach can be applied to any other rock type and enables the tracking of microstructural trends in grains arrangement.

Directional Decremental Abundance of (GA)9 and (GA)11 Blocks in Primate Speciation

Background: Recent evidence indicates that expansion of a number of short tandem repeats (STRs) may be a result of natural selection. The human neuron-specific genes, RIT2 and GPM6B, contain two of the longest GA-STRs at 11 and 9-repeats, respectively, the length ranges of which are functional, and exceedingly rare repeats at the extreme end of those STRs occur with major human disorders. To examine the evolutionary trend of (GA)11 and (GA)9 blocks, two sets of chromosomal regions (each spanning 10 Mb of genomic DNA) across all chromosomes, were searched for those blocks across rodent and primate orders. We also sequenced the RIT2 and GPM6B STRs in 600 human subjects, consisting of late-onset neurocognitive disorder (n=200), multiple sclerosis (n=100), and controls (n=200). Results: We detected a directional decremental abundance of (GA)11 and (GA)9 blocks, matching the phylogenetic distance of the selected species as follows: mouse>macaque>great apes (p=0.000006). The RIT2 and GPM6B GA-repeats were at strict lengths of 11 and 9-repeats in human, respectively, and were predominantly human-specific in formula. Exception included a 9/11 genotype of the RIT2 GA-STR in an isolate case of multiple sclerosis. Conclusion: We report the first evidence of massive directional trend of STRs linking to speciation. Genes such as RIT2 and GPM6B may be suitable candidates to explore the evolutionary impact of STR blocks.

Movement of individual humpback whales between wintering grounds of Oceania (South Pacific), 1999 to 2004

The movement of individual humpback whales between regional breeding grounds of Oceania (South Pacific) was documented by individualidentification photographs collected from 1999 to 2004. Photographs were collected with comparable effort across the six years in four primaryisland breeding grounds: New Caledonia, Tonga (Vava’u) the Cook Islands and French Polynesia (Mo’orea and Rurutu); with smaller effort inadjacent regions: Vanuatu, Fiji, Samoa, Niue and American Samoa. Interchange among wintering grounds was assessed first with all usablephotographs included in each regional catalogue, representing 1,080 regional sightings (including within-region and between-region resightings)of 949 individual whales from Oceania. From this, 28 cases of movement between (mostly adjacent) regions were documented. Previouslyundocumented interchange was found between regions of central Oceania and the western South Pacific. No individual was sighted in more thantwo regions during this six-year period. The documented movement between regions was one-directional, except for one individual sighted first inFrench Polynesia, then in American Samoa and then back in French Polynesia (each in different years). Only one whale was resighted in more thanone region during the same winter season. No directional trend was apparent and movement between regions did not seem to be sex specific. Asystematic quality control review of all catalogues was then implemented to calculate standardised indices of within-region return and betweenregion interchange, resulting in a quality controlled catalogue of 776 regional sightings of 659 individuals. The standardised indices confirmed thatthe probability of between-region interchange was low, relative to within-region return, supporting the assumption of multiple management unitsor stocks in Oceania. The relative isolation of breeding regions and the movement of individuals across the longitudinal borders of Antarcticmanagement Areas V and VI has important implications for the allocation of historical catches from the Antarctic and therefore, for assessingcurrent levels of recovery for breeding stocks

The Market Sentiment Trend, Investor Inertia, and Post-Earnings Announcement Drift: Evidence from Korea’s Stock Market

We investigated whether post-earnings announcement drift (PEAD) in the Korean stock market is related to investor inertial behavior under a directional trend in market sentiment. Given that investors tend to procrastinate due to their belief in the persistence of the current market’s condition and thus underreact to earnings information, we examined whether this investor inertia influences the drift in stock price following an earnings announcement. Our findings show that when the market sentiment continues to shift upwardly (downwardly) over the pre- and post-earnings announcement period, positive (negative) drift occurs. Note that these results are robust to control for the effect of market sentiment at a specific point in time. We suggest that investors do not fully respond to new earnings information due to investor inertial behavior under the market sentiment with a consistent trend. Overall, our study sheds light on a determinant of PEAD as one of the market anomalies in terms of investors’ cognitive bias by documenting the relation between PEAD and investor inertia.

Evolutionary parallelisms of pectoral and pelvic network-anatomy from fins to limbs

Lobe-fins transformed into limbs during the Devonian period, facilitating the water-to-land transition in tetrapods. We traced the evolution of well-articulated skeletons across the fins-to-limbs transition, using a network-based approach to quantify and compare topological features of fins and limbs. We show that the topological arrangement of bones in pectoral and pelvic appendages evolved in parallel during the fins-to-limbs transition, occupying overlapping regions of the morphospace, following a directional trend, and decreasing their disparity over time. We identify the presence of digits as the morphological novelty triggering topological changes that discriminated limbs from fins. The origin of digits caused an evolutionary shift toward appendages that were less densely and heterogeneously connected, but more assortative and modular. Disparity likewise decreased for both appendages, more markedly until a time concomitant with the earliest-known tetrapod tracks. Last, we rejected the presence of a pectoral-pelvic similarity bottleneck at the origin of tetrapods.

Trends in Postoperative Opioid Prescribing in Outpatient Pediatric Surgery

Objective To determine trends in opioid prescribing for home use after pediatric outpatient surgery. Design Retrospective analysis of a de-identified database. Setting Multispecialty children’s hospital and freestanding surgery centers. Patients, Participants A total of 65,190 encounters of pediatric outpatient surgeries from 2013 through 2017 for nine different surgical specialties. Patients in the cardiothoracic service and nonpainful procedures were excluded. Main Outcome Measures. Incidence rate of prescribing, dose, number of doses available (i.e., duration of therapy), and maximum weight-based home opioid availability from 2013 to 2017. Additional independent variables included sex, age, weight, race/ethnicity, insurance type (private vs public), and surgical service. Results The incidence rate of receiving a take-home opioid prescription at discharge ranged from 18% to 21% between 2013 and 2017, with no clear directional trend. Among patients prescribed opioids, however, the maximum available take-home dose steadily declined from 2013 through 2017 (P < 0.001). This was due to both a decrease in the number of doses prescribed (i.e., duration of treatment) and, beginning in 2015, the amount per dose. Females were more likely to receive an opioid than males, and patients with public insurance were more likely to receive an opioid than those with private insurance. Opioid prescribing was more likely in patients who did not disclose their ethnicity and those of ethnic minority compared with white patients (all P < 0.0001). Conclusions The rate of receiving a take-home opioid prescription and the dose prescribed remained stable from 2013 to 2017, but the duration of treatment steadily declined, and beginning in 2015, the amount per dose also decreased. Certain subgroups of patients were more likely to be prescribed opioids and will require further investigation and confirmation.