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We present efficient computational solutions to the problems of checking equality, performing multiplication, and computing minimal representatives of elements of free bands. A band is any semigroup satisfying the identity $x ^ 2 \approx x$ and the free band $\operatorname{FB}(k)$ is the free object in the variety of $k$-generated bands. Radoszewski and Rytter developed a linear time algorithm for checking whether two words represent the same element of a free band. In this paper we describe an alternate linear time algorithm for checking the same problem. The algorithm we present utilises a representation of words as synchronous deterministic transducers that lend themselves to efficient (quadratic in the size of the alphabet) multiplication in the free band. This representation also provides a means of finding the short-lex least word representing a given free band element with quadratic complexity., 31 pages, 12 figures (fix some minor typos and other issues, to appear in Theoretical Computer Science)

BACKGROUND: The optimal anastomotic techniques in esophagectomy to minimize rates of anastomotic leakage and conduit necrosis are not known. The aim of this study was to assess whether the anastomotic technique was associated with anastomotic failure after esophagectomy in the international Oesophago-Gastric Anastomosis Audit cohort.METHODS: This prospective observational multicenter cohort study included patients undergoing esophagectomy for esophageal cancer over 9 months during 2018. The primary exposure was the anastomotic technique, classified as handsewn, linear stapled, or circular stapled. The primary outcome was anastomotic failure, namely a composite of anastomotic leakage and conduit necrosis, as defined by the Esophageal Complications Consensus Group. Multivariable logistic regression modeling was used to identify the association between anastomotic techniques and anastomotic failure, after adjustment for confounders.RESULTS: Of the 2238 esophagectomies, the anastomosis was handsewn in 27.1%, linear stapled in 21.0%, and circular stapled in 51.9%. Anastomotic techniques differed significantly by the anastomosis sites (P < .001), with the majority of neck anastomoses being handsewn (69.9%), whereas most chest anastomoses were stapled (66.3% circular stapled and 19.3% linear stapled). Rates of anastomotic failure differed significantly among the anastomotic techniques (P < .001), from 19.3% in handsewn anastomoses, to 14.0% in linear stapled anastomoses, and 12.1% in circular stapled anastomoses. This effect remained significant after adjustment for confounding factors on multivariable analysis, with an odds ratio of 0.63 (95% CI, 0.46-0.86; P = .004) for circular stapled versus handsewn anastomosis. However, subgroup analysis by anastomosis site suggested that this effect was predominantly present in neck anastomoses, with anastomotic failure rates of 23.2% versus 14.6% versus 5.9% for handsewn versus linear stapled anastomoses versus circular stapled neck anastomoses, compared with 13.7% versus 13.8% versus 12.2% for chest anastomoses.CONCLUSIONS: Handsewn anastomoses appear to be independently associated with higher rates of anastomotic failure compared with stapled anastomoses. However, this effect seems to be largely confined to neck anastomoses, with minimal differences between techniques observed for chest anastomoses. Further research into standardization of anastomotic approach and techniques may further improve outcomes.

Alates of the fungus-growing termite Macrotermes natalensis (Haviland), a pest of building structures and forestry, were collected during swarming flights in Pretoria, South Africa (25°43′S 28°14′E), during the early summers of 1997 and 1998. Incipient colonies were reared in the laboratory with colony foundation and development and caste differentiation being observed over three months. Early colony mortality was high, with only a 4 % survival rate over three months. Oviposition began 4–12 days after pairing, with all females collected after a specific swarming flight starting to lay on the same day. The oviposition rate was initially high, with a mean of 17.85 (S.E. ± 1.314) eggs per individual being laid in the initial clutch; thereafter, the rate decreased to a mean of 1.7 (S.E. ± 0.078) eggs per day. Following hatching, the rate of oviposition decreased further to 0.9 eggs per day (S.E. ± 0.3049). Incubation of eggs varied between 20 and 34 days. As with oviposition, hatching started on the same day in all colonies set up after a specific swarming flight; however, not all the eggs laid on that specific date hatched simultaneously. Second (L2) and third (L3) instar larvae first appeared in the colonies a mean of 6.6 (S.E. ± 0.578) days and 11.5 (S.E. ± 0.3193) days, respectively, after the first eggs hatched. The first pre-soldier (SPS), which developed from a third instar larva, was differentiated a mean of 21.85 (S.E. ± 0.748) days after hatching, with the first soldier (SS) appearing 30.75 (S.E. ± 0.4787) days following hatching. The first major (LW) and minor (SW) workers were differentiated respectively 26 ± 0.660 and 28 ± 0.905 days after hatching. Approximately three months after alates had left the parent nest, workers began foraging. At three months, the single surviving colony contained 60 individuals. No large soldier (LS) had differentiation by 20 months.

Trinervitermes trinervoides (Sjostedt) (Termitidae: Nasutitermitinae) is principally a grass litterfeeding species common to the semi-arid and arid grasslands of southernAfrica. Abundance of sterile adult termites (workers and soldiers) at eight sites within an area of semi-arid grassland, northwest of Bloemfontein in the Free State Province, varied between 34 and 4871/m2 (mean=2261/m2) with a live biomass of 0.2 to 27.8 g/m2 (mean=12.9 g/m2). The numbers of live mounds in an area do not necessarily reflect termite abundance. At two sites at Bultfontein fewer termites and lower biomass were present on the site with 137 mounds/ha than that with 97 mounds/ha. Experimental studies on grass consumption of artificially fed field colonies of different sizes were used to estimate consumption by termites at the different sites. Consumption at the various experimental sites varied between 2.7 and 451.2 kg/ha/year (mean: 203.4 ± 175.1 kg/ha/year) and a marked seasonal periodicity in consumption was demonstrated. The impact of T. trinervoides within well-managed grassland ecosystems where the litter-feeding species forman important link in the food chain, is chiefly beneficial and far outweigh its harmful effects which tend to be associated with degraded, overgrazed grassland and drought.

The size of harvester termite Hodotermes mossambicus (Hagen) (Isoptera: Hodotermitidae) populations on the clay-rich red-soils of semi-arid grasslands in southwestern Zimbabwe in any particular dry season was found to be strongly influenced by the annual rainfall received the preceding rainy season. The size of the termite population of the antecedent dry season also had an important influence. Populations were found to build up over successive dry years and crashed following a season of substantially above average rainfall to fall further after the next rainy season which was also above average. Termite populations and foraging activity also fluctuated considerably within seasons. There was an increase as the dry season progressed but foraging fell dramatically at the end of the season and remained at low levels throughout the summer months. Foraging was confined to degraded patches in the red-soil veld mosaic in the early dry season with expansion into the other grass communities occurring in the late dry season. Fluctuations in harvester termite populations had a marked effect on the extent of the foraging area and hence on the amounts of grass cover remaining in the degraded, ecotone and sound veld communities of the red-soil mosaic at the end of the dry season. Termite foraging activities serve to maintain the grass sward in a vigorous condition by preventing excessive accumulation of dead foliage on ungrazed sites and they had an important influence on the botanical changes which occurred within each grass community of the mosaic. The main effect was to favour those grass species such as Heteropogon contortus and Themeda triandra, that are intolerant of excessive top-hamper (standing dead grass) and litter accumulation.

In 2012, we instituted detailed prospective peer review of new cases. We present the outcomes of peer review on patient management and time required for peer review.Peer review rounds were held 3 to 4 days weekly and required 2 physicians to review pertinent information from the electronic medical record and treatment planning system. Eight aspects were reviewed for each case: 1) workup and staging; 2) treatment intent and prescription; 3) position, immobilization, and simulation; 4) motion assessment and management; 5) target contours; 6) normal tissue contours; 7) target dosimetry; and 8) normal tissue dosimetry. Cases were marked as, "Meets standard of care," "Variation," or "Major deviation." Changes in treatment plan were noted. As our process evolved, we recorded the time spent reviewing each case.From 2012 to 2014, we collected peer review data on 442 of 465 (95%) radiation therapy patients treated in our hospital-based clinic. Overall, 91 (20.6%) of the cases were marked as having a variation, and 3 (0.7%) as major deviation. Forty-two (9.5%) of the cases were altered after peer review. An overall peer review score of "Variation" or "Major deviation" was highly associated with a change in treatment plan (P.01). Changes in target contours were recommended in 10% of cases. Gastrointestinal cases were significantly associated with a change in treatment plan after peer review. Indicators on position, immobilization, simulation, target contours, target dosimetry, motion management, normal tissue contours, and normal tissue dosimetry were significantly associated with a change in treatment plan. The mean time spent on each case was 7 minutes.Prospective peer review is feasible in a community radiation oncology practice. Our process led to changes in 9.5% of cases. Peer review should focus on technical factors such as target contours and dosimetry. Peer review required 7 minutes per case.

Nest populations or colonies of the harvester termite, Trinervitermes trinervoides (Sjostedt) (Termitidae: Nasutitermitinae), which commonly occurs in the semi-arid grasslands of southern Africa, were assessed. The entire contents of nests, mounds and subterranean sections were excavated following fumigation. Termites were extracted by flotation from volumetric sub-samples of the nest material and counted. Nest populations were found to be considerably larger than those of other members of the genus. Sterile adult populations varied from 9000 in small mounds (height = 12 cm) to 889 000 in large mounds (height = 59 cm). Workers, major and minor soldiers make up 75%, 9% and 16%, respectively, of the total adult sterile population. The proportion of soldiers decreased with increasing colony size, constituting 51% of populations of the smallest nest and only 16% of a large nest. This decrease in total soldier proportions in larger nests reflected a decrease in the proportion of minor soldiers. Ratios of worke...

Purpose To report the interfraction and intrafraction setup variation for prone breast radiotherapy and to determine an appropriate clinical tumor volume (CTV) to planning target volume (PTV)_ margin to account for motion and positional uncertainties. Methods and Materials Ten consecutive patients were prospectively enrolled in a protocol of accelerated, hypofractionated prone breast irradiation. Portal images were acquired using an electronic portal imaging device in cine mode. Interfraction setup error was determined by comparing the first image from each fraction with the digitally reconstructed radiograph. The intrafraction motion was determined by evaluating every image acquired during each fraction and measuring the maximum displacement of an external fiducial and the breast surface. Mean values and 95% confidence intervals (CI) were calculated. Based on these results, a CTV to PTV expansion was derived using the equation M=2.5Σ tot + 0.7σ tot. Results The mean interfraction setup variability for the fiducial was 0.08 cm (CI: 0.02–0.14) in the anterior to posterior (AP) direction and −0.04 cm (CI: −0.07–0.00) in the superior to inferior (SI) direction. The mean interfraction variability of the breast surface was −0.14 cm (CI: −0.24 to −0.04) in the AP direction. The mean intrafraction displacements of the fiducial and the breast surface were 0.13 cm (CI: 0.12–0.15) and 0.15 cm (CI: 0.14–0.17), respectively. Using the systematic and random errors for the external fiducial, the calculated CTV to PTV expansion was 1.4 cm. Conclusions Acceptable interfraction and intrafraction variability were demonstrated. The findings resulted in a CTV to PTV expansion of 1.4 cm.

Foraging behaviour and the diurnal and seasonal foraging periodicity of the southern African snouted harvester termite, Trinervitermes trinervoides (Sjostedt), are described. The termite usually foraged during summer nights when ambient temperatures were 10–14 °C. Foraging occurred at temperatures between 13–25 °C under laboratory conditions. A foraging party emerging from a single hole harvested over an area of approximately 0.78 m2. A colony exploited a total area of approximately 214 m2 and foraging areas of adjacent colonies overlapped. Colonies occupy single mounds.

In this study, we present a case of laparoscopic ovarian transposition to preserve ovarian function in an adult female patient treated with craniospinal irradiation for standard risk medulloblastoma. The prescribed dose to the craniospinal axis was 2340 cGy at 180 cGy per fraction and was delivered with 6-MV photons. Before ovarian transposition, magnetic resonance imaging (MRI) of the pelvis was obtained for localization of the ovaries and was registered with the planning computed tomography (CT) scan. Surgical clips allowed for CT localization of the ovaries after transposition. As a result of ovarian transposition, mean and maximum radiation doses decreased from 983 to 68 cGy and 1624 to 84 cGy for the left ovary and from 166 to 87 cGy and 723 to 103 cGy for the right ovary, respectively. Review of the literature indicates that such radiation doses are below the threshold that causes ovarian dysfunction and infertility. We conclude that ovarian localization with an MRI of the pelvis can be offered to females undergoing craniospinal irradiation. Transposition of the ovaries provides an option to preserve ovarian function in cases where the ovaries would otherwise be included within the radiation field.

Induced suit and body currents are described and evaluated. A suit and body resistance model is used to evaluate the effect on wearer comfort of suit resistance and suit-to-body bonding. Suit resistance is not constant, but depends on the measuring current. The resistance increases with laundering, and its effective value falls sharply in a strong electric field. Mechanisms are proposed to explain these effects. A recommendation is made regarding the maximum suit resistance.

A method for detection and removal of random spike noise in magnetic resonance (MR) raw data (k-space data) is described. This method would reduce or eliminate the corduroy-type and higher than usual level artifacts in MR images resulting from random spike noise in k-space data. The method described involves applying a spatially varying threshold to be k-space data. Any data point that has a magnitude greater than that of the threshold value at that location will be replaced by a local complex average of the neighboring data points or some other suitable data replacement scheme. >

The CTMax of pigmented major and minor workers and unpigmented larvae of Hodotermes mossambicus (Hagen) from laboratory colonies range between 43.5–48.53°C while the CTMin range between 5.3–10.31°C over a range of acclimation temperatures between 15 and 35°C. Major and minor workers have both higher CTMax and lower CTMin than unpigmented large larvae. Temperature tolerance limits are influenced by a number of factors such as the age or maturity of the individual, its size and colour, previous thermal history, the extent of its water reserves as well as environmental conditions.

A system is described which introduces a cooling system based on a proportional liquid nitrogen control valve. This is driven directly from the 3 term P.I.D. output of the DSC controller which in turn is controlled directly from the Polymer Laboratories Limited software system. The proportioning valve adjusts the amount of liquid nitrogen required by the DSC as determined by the P.I.D. control algorithm. By varying the nitrogen flow according to demand, absolute repeatability is ensured from run to run and a considerable saving in liquid nitrogen is achieved. Thus the DSC performs identically in heating or cooling mode.

The stability characteristics of the anti-symmetric TE 1 stationary wave in symmetric nonlinear planar waveguides (SNPW) is investigated both analytically and numerically. It is shown, for the first time, that eigenvalues of the corresponding linear stability analysis can be complex in a certain range of parameters. This fact makes the range of instability of the TE 1 wave broader than in studies where the eigenvalues are restricted to being only real or purely imaginary. Nevertheless, for high values of the propagation constant β, the TE 1 wave is stable, in contrast to the symmetric TE 0 wave which is unstable at high values of β.

Purpose: To examine the acute morbidity of high dose head and neck RT and CRT in patients with infected with HIV. Methods and Materials: All HIV-positive patients who underwent radiation therapy for head and neck cancer in our department between 2004 and 2008 were reviewed. Treatment related data were examined. All treatments were delivered with megavoltage photon beams or electron beams. Patients were evaluated by an attending radiation oncologist for toxicity and response on a weekly basis during therapy and monthly after treatment in a multidisciplinary clinic. Acute toxicities were recorded using the Radiation Therapy and Oncology Group (RTOG) common toxicity criteria. Response to treatment was based on both physical exam as well as post-treatment imaging as indicated. Results: Thirteen patients who underwent RT with a diagnosis of HIV were identified. Median age was 53 years and median follow-up was 22 months. Twelve had squamous cell carcinoma and one had lymphoproliferative parotiditis. Median radiation dose was 66.4 Gy and median duration of treatment was 51 days. The median number of scheduled radiotherapy days missed was zero (range 0 to 7). One patient (8%) developed Grade 4 confluent moist desquamation. Eight patients (61%) developed Grade 3 toxicity. Conclusion: Based on ourmore » results, HIV-positive individuals appear to tolerate treatment for head and neck cancer, with toxicity similar to that in HIV-negative individuals.« less

This paper analyzes fault tolerance of spacecraft relative navigation in automated rendezvous and docking (AR&D). The relatively low technology readiness of existing relative navigation sensors for AR&D has been carried as one of the NASA crew exploration vehicle project's top tasks. Fault tolerance could be enhanced with the help of FDIR (fault detection, identification and recovery) logic and use of redundant sensors. Because of mass and power constraints, it is important to choose a fault tolerant design that provides the required reliability without adding excessive hardware. An important design trade is determining whether a redundant sensor can be normally unpowered and activated only when necessary. This paper analyzes reliability trades for such fault tolerant system. A Markov Chain model of the system is composed of sub-models for sensor faults and for sensor avionics states. The sensor fault sub-model parameters are based on sensor testing data. The avionics sub-model includes FDIR states; the parameters are determined by Monte Carlo simulations of the near field docking approach. The integrated Markov Chain model allows the probabilities of mission abort and a mishap to be computed. The results of the trade study include dependence of the probabilities on the backup sensor activation delay.

The exploration systems architecture defines missions that require rendezvous, proximity operations, and docking (RPOD) of two spacecraft both in low earth orbit (LEO) and in low lunar orbit (LLO). Uncrewed spacecraft must perform automated and/or autonomous rendezvous, proximity operations and docking operations (commonly known as ARD (2) CEV-specific trajectories designed to test performance during CEV-like approach and departure profiles; and (3) sensor characterization tests designed for evaluating sensor performance under more extreme conditions as might be induced during a spacecraft failure or during contingency situations. This paper describes the test development, test facility, test preparations, test execution, and test results of the multi- sensor series of trajectories.

Purpose: To report the physics and dosimetry results of a trial of accelerated intensity-modulated radiotherapy to the whole breast with a concomitant boost to the tumor bed in patients treated in the prone position. Methods and Materials: Patients underwent computed tomography planning and treatment in the prone position on a dedicated treatment platform. The platform has an open aperture on the side to allow for the index breast to fall away from the chest wall. Noncontrast computed tomography images were acquired at 2.5- or 3.75-mm-thick intervals, from the level of the mandible to below the diaphragm. A dose of 40.5 Gy was delivered to the entire breast at 2.7-Gy fractions in 15 fractions. An additional dose of 0.5 Gy was delivered as a concomitant boost to the lumpectomy site, with a 1-cm margin, using inverse planning, for a total dose of 48 Gy in 15 fractions. No more than 10% of the heart and lung volume was allowed to receive >18 and >20 Gy, respectively. Results: Between September 2003 and August 2005, 91 patients were enrolled in the study. The median volume of heart that received ≥18 Gy was 0.5%, with a maximal value of 4.7%. The median volume of ipsilateral lung that received ≥20 Gy was 0.8%, with a maximum of 7.2%. Conclusion: This technique for whole breast radiotherapy is feasible and enables an accelerated regimen in the prone position while sparing the lung and heart.

The Exploration Systems Architecture defines missions that require rendezvous, proximity operations, and docking (RPOD) of two spacecraft both in Low Earth Orbit (LEO) and in Low Lunar Orbit (LLO). Uncrewed spacecraft must perform automated and/or autonomous rendezvous, proximity operations and docking operations (commonly known as Automated Rendezvous and Docking, AR&D). The crewed versions may also perform AR&D, possibly with a different level of automation and/or autonomy, and must also provide the crew with relative navigation information for manual piloting. The capabilities of the RPOD sensors are critical to the success of the Exploration Program. NASA has the responsibility to determine whether the Crew Exploration Vehicle (CEV) contractor-proposed relative navigation sensor suite will meet the CEV requirements. The relatively low technology readiness of relative navigation sensors for AR&D has been carried as one of the CEV Projects top risks. The AR&D Sensor Technology Project seeks to reduce this risk by increasing technology maturation of selected relative navigation sensor technologies through testing and simulation, and to allow the CEV Project to assess the relative navigation sensors.

Publisher Summary A host of non-neurological diseases and environmental exposures may either be associated with amyotrophic lateral sclerosis (ALS)/motor neuron disorders (MND) mimic syndromes or even be potential causes of MNDs. This chapter reviews the evidence relating to the occurrence of ALS/MND in relation to physical exposures and endocrine disease and provides specific neurophysiological features. Patients treated in intensive care units (ICUs) sometimes develop limb weakness not readily explicable on the basis of the working diagnosis. Associations between the occurrence of ALS and exposure to ionizing radiation are discussed in the chapter. The biologically harmful effects of ionizing radiation are mediated through the ability to induce the formation of ionic species that contain unpaired electrons and thus trigger free radical reactions. Environmental exposures also influence the links between radiation therapy and MND. A wide range of potential endocrine associations have arisen to unravel the etiological basis of the human MNDs. While these have clearly not led to a unifying etiological hypothesis, a number of weak associations have emerged, and the general significance of them remains uncertain.

This paper presents result of research on the application of a portable protective gap (PPG) to live work on a compact 550 kV steel lattice tower, The objective of the research was to provide experimental evidence which confirms the needed coordination of the PPG sparkover characteristics with the sparkover characteristics of the worksite on the compact tower during live work. Sparkover characteristics of the worksite are strongly affected by the presence of the worker, the live working tools, and damaged insulators.

There have been no reports of changes in free radical inactivating enzymes in the anterior horn of the spinal cord in ALS despite great interest in the possibility that free radicals might be important in the aetiology of the disease. In this study we have measured copper/zinc superoxide dismutase (Cu/ZnSOD), manganese superoxide dismutase (MnSOD) and glutathione peroxidase (GSHPX) activities in anterior horn tissue obtained from patients with ALS and from controls. Total SOD activity was no different in the anterior horn of ALS cases compared to controls, but Cu/ZnSOD activity was reduced, and that of MnSOD increased, at thoracic cord level only. No detectable activity of GSHPX or cytochrome P 450 (unpublished data) was found. These latter negative findings are important because they suggest that generation of free radicals from exogenous chemicals is not important in ALS and further that the neurone (as compared to other cell types) is poorly protected against the toxicity of hydrogen peroxide.

Studies on anterior horn dissected from MND patients have demonstrated that MnSOD activity is increased when expressed as a percentage of total SOD activity when compared to controls. Total SOD activity (mean +/- SD) in controls = 414 +/- 105 U mg-1 tissue and in MND patients = 373 +/- 115 U mg-1 tissue, whereas CuZnSOD activity was higher in controls (290 +/- 91 U mg-1 tissue) than in MND patients (197 +/- 81 U mg-1 tissue). The reduction in CuZnSOD was compensated for by a concomitant elevation of MnSOD activity (control = 123 +/- 40.5 U mg-1 tissue, MND patients = 175 +/- 47 U mg-1 tissue). These data not only show an important deficit in anterior horn cell body protection against free radical-mediated cell damage, but are also are the first measurements of SOD isoenzymes in anterior horn neurones.