Qualitative models for planning: A gentle introduction

Qualitative modeling is the study of how the physical world behaves. These physical models accept partial descriptions of the world and output the possible changes. Current systems assume that the model is static and that physical entities do not effect change into the world. An approach to planning in physical domains and a working implementation which integrates qualitative models with a temporal interval-based planner are described. The planner constructs plans involving physical qualities and their behavioral descriptions

Mrs. C.D. Carnes to Mr. Meredith (1 October 1962)

https://egrove.olemiss.edu/mercorr_pro/1363/thumbnail.jp

Shedding in the Timber Rattlesnake: Natural Patterns, Endocrinological Underpinnings, Temporal and Energetic Effort, and Integration as a Reptilian Life History Trait

The semi-frequent replacement of the epidermis (ecdysis) is a characteristic trait of reptiles. Whereas all reptiles regularly engage in some degree of skin shedding, skin morphology in snakes necessitates the synchronous replacement of the entire epidermis and facilitates the subsequent removal of the old layer as a single sheet. To date, the ubiquitous process has garnered little attention from researchers because snakes shed with unpredictable timing and frequency and are exceedingly cryptic during ecdytic cycles; previously impeding detailed physiological or ecological investigations of the process in the clade. Because of the lack of study, ecdysis is often viewed as a maintenance function; occurring whenever change in body size necessitates the generation of a new epidermal layer. However, recent observations that skin shedding plays a role in conspecific sexual signaling in some snakes suggest that the predominate view of ecdysis as a growth function may be overly simplistic. By studying population-scale patterns of shed, I was able to describe the timing and frequency of ecdysis in a population of Timber Rattlesnakes, solving a long-standing problem in continued study of ecdysis; predicting the occurrence of shed events. Coupling my knowledge of patterns of shed timing with novel methodologies for inducing shed, I was able to induce ecdytic cycles in a laboratory setting and herein provide the first measurements of the metabolic effort and duration of shedding in any reptile. I integrated data on the frequency, duration, and metabolic effort of shed into an individual-based computer model of the Timber Rattlesnake to address larger questions about the selective pressures that may shape patterns of shed in snakes. I found that Timber Rattlesnakes shed infrequently (1-2 times per year) and often in close proximity to the mating season regardless of sex. However, the physiological conditions that best correlated to shed frequency differed between males (body condition) and females (reproductive condition). Each shed event required a significant metabolic (3% of the total annual energy budget) and temporal (~28 days at 25⁰C with ~50% of that including some degree of visual limitation from occluded spectacles) investment. In my computer simulations, I found that time spent in shed limited lifetime energy budgets (decreasing lifetime resource acquisition via foraging) and that the energetic effort of ecdysis may serve to limit shed frequency in low resource environments. In my observations of patterns of shed in the wild and through simulations of expected female fecundity under alternate shed frequencies, I found evidence that ecdysis may play a vital role in the reproductive biology of rattlesnakes. Ecdysis is a vital and omnipresent feature of reptilian biology. My data are the first to demonstrate that the frequency of the process is constrained in a population. I provide evidence for the role of growth and body condition, time-energy budgets, environmental conditions, and reproductive events in dictating patterns of shed. As such, patterns of shed may be population specific and serve as an indicator of the important environmental and biophysical forces which shape life histories across populations and species

Shedding in the Timber Rattlesnake: Natural Patterns, Endocrinological Underpinnings, Temporal and Energetic Effort, and Integration as a Reptilian Life History Trait

The semi-frequent replacement of the epidermis (ecdysis) is a characteristic trait of reptiles. Whereas all reptiles regularly engage in some degree of skin shedding, skin morphology in snakes necessitates the synchronous replacement of the entire epidermis and facilitates the subsequent removal of the old layer as a single sheet. To date, the ubiquitous process has garnered little attention from researchers because snakes shed with unpredictable timing and frequency and are exceedingly cryptic during ecdytic cycles; previously impeding detailed physiological or ecological investigations of the process in the clade. Because of the lack of study, ecdysis is often viewed as a maintenance function; occurring whenever change in body size necessitates the generation of a new epidermal layer. However, recent observations that skin shedding plays a role in conspecific sexual signaling in some snakes suggest that the predominate view of ecdysis as a growth function may be overly simplistic. By studying population-scale patterns of shed, I was able to describe the timing and frequency of ecdysis in a population of Timber Rattlesnakes, solving a long-standing problem in continued study of ecdysis; predicting the occurrence of shed events. Coupling my knowledge of patterns of shed timing with novel methodologies for inducing shed, I was able to induce ecdytic cycles in a laboratory setting and herein provide the first measurements of the metabolic effort and duration of shedding in any reptile. I integrated data on the frequency, duration, and metabolic effort of shed into an individual-based computer model of the Timber Rattlesnake to address larger questions about the selective pressures that may shape patterns of shed in snakes. I found that Timber Rattlesnakes shed infrequently (1-2 times per year) and often in close proximity to the mating season regardless of sex. However, the physiological conditions that best correlated to shed frequency differed between males (body condition) and females (reproductive condition). Each shed event required a significant metabolic (3% of the total annual energy budget) and temporal (~28 days at 25⁰C with ~50% of that including some degree of visual limitation from occluded spectacles) investment. In my computer simulations, I found that time spent in shed limited lifetime energy budgets (decreasing lifetime resource acquisition via foraging) and that the energetic effort of ecdysis may serve to limit shed frequency in low resource environments. In my observations of patterns of shed in the wild and through simulations of expected female fecundity under alternate shed frequencies, I found evidence that ecdysis may play a vital role in the reproductive biology of rattlesnakes. Ecdysis is a vital and omnipresent feature of reptilian biology. My data are the first to demonstrate that the frequency of the process is constrained in a population. I provide evidence for the role of growth and body condition, time-energy budgets, environmental conditions, and reproductive events in dictating patterns of shed. As such, patterns of shed may be population specific and serve as an indicator of the important environmental and biophysical forces which shape life histories across populations and species

Effects of radiation on charge-coupled devices

The effects of 1 MeV electron irradiation upon the performance of two phase, polysilicon aluminum gate CCDs are reported. Both n- and p-surface channel and n-buried channel devices are investigated using 64- and 128-stage line arrays. Characteristics measured as a function of radiation dose include: Transfer inefficiency, threshold voltage, field effect mobility, interface state density, full well signal level and dark current. Surface channel devices are found to degrade considerably at less than 10 to the 5th power rads (Si) due to the large increase in fast interface state density caused by radiation. Buried channel devices maintain efficient operation to the highest dose levels used

Coping with Persistent Pain, Effectiveness Research into Self-management (COPERS): statistical analysis plan for a randomised controlled trial

This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly credited. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated

The effectiveness and safety of conservative interventions for positional plagiocephaly and congenital muscular torticollis: A synthesis of systematic reviews and guidance

Aim: To investigate for congenital muscular torticollis (CMT) and positional plagiocephaly (PP) the effectiveness and safety of manual therapy, repositioning and helmet therapy (PP only) using a systematic review of systematic reviews and national guidelines. Methods: We searched four major relevant databases: PubMed, Embase, Cochrane and MANTIS for research studies published between the period 1999-2019. Inclusion criteria were systematic reviews that analysed results from multiple studies and guidelines that used evidence and expert opinion to recommend treatment and care approaches. Three reviewers independently selected articles by title, abstract and full paper review, and extracted data. Selected studies were described by two authors and assessed for quality. Where possible meta-analysed data for change in outcomes (range of movement and head shape) were extracted and qualitative conclusions were assessed. Results: We found 10 systematic reviews for PP and 4 for CMT. One national guideline was found for each PP and CMT. For PP, manual therapy was found to be more effective than repositioning including tummy time (moderate to high evidence) but not better than helmet therapy (low evidence). Helmet therapy was better than usual care or repositioning (low evidence); and repositioning better than usual care (moderate to high evidence). The results for CMT showed that manual therapy in the form of practitioner-led stretching had moderate favourable evidence for increased range of movement. Advice, guidance and parental support was recommended in all the guidance to reassure parents of the favourable trajectory and nature of these conditions over time. Conclusions: Distinguishing between superiority of treatments was difficult due to the lack of standardised measurement systems, the variety of outcomes and limited high quality studies. More well powered effectiveness and efficacy studies are needed. However overall, advice and guidance on repositioning (including tummy-time) and practitioner-led stretching were low risk, potentially helpful and inexpensive interventions for parents to consider. Systematic review registration number: PROSPERO 2019 CRD42019139074. © 2020 The Author(s)

Carrier-envelope phase control over pathway interference in strong-field dissociation of H2+_2^+

The dissociation of an H$_2^+$ molecular-ion beam by linearly polarized, carrier-envelope-phase-tagged 5 fs pulses at 4$\times10^{14}$W/cm$^2$ with a central wavelength of 730 nm was studied using a coincidence 3D momentum imaging technique. Carrier-envelope-phase-dependent asymmetries in the emission direction of H$^+$ fragments relative to the laser polarization were observed. These asymmetries are caused by interference of odd and even photon number pathways, where net-zero photon and 1-photon interference predominantly contributes at H$^+$+H kinetic energy releases of 0.2 -- 0.45 eV, and net-2-photon and 1-photon interference contributes at 1.65 -- 1.9 eV. These measurements of the benchmark H$_2^+$ molecule offer the distinct advantage that they can be quantitatively compared with \textit{ab initio} theory to confirm our understanding of strong-field coherent control via the carrier-envelope phase