Rotational Shift Research Articles

Envy-Free Allocation by Sperner’s Lemma Adapted to Rotation Shifts in a Company

This article discusses a theoretical construction based on the graph theory to rework the space of potential partitions in envy-free distribution. This work has the objective of applying Sperner’s lemma to the distribution of three rotating shifts for three workers who are to cover a 24 h job position in a company. As a novel feature, worker’s preferences have been modeled as functions of probability for the three shifts, according to salary offers for said shifts. Envy-free allocation was achieved, since each worker received their preferred shift without the need for negotiation between agents in conflict. Adaptation to the type of dynamic situations that arise with rotating shifts, as well as the consideration of probabilistic preferences by workers are some of the main novelties of this work.

Rotational positional error-corrected linear set-up margin calculation technique for lung stereotactic body radiotherapy in a dual imaging environment of 4-D cone beam CT and ExacTrac stereoscopic imaging.

Accurate calculation of set-up margin is a prerequisite to arrive at the most optimal clinical to planning target volume margin. The aim of this study was to evaluate the compatibility of different on-board and in-room stereoscopic imaging modalities by calculating the set-up margins (SM) in stereotactic body radiotherapy technique accounting and unaccounting for rotational positional errors (PE). Further, we calculated separate SMs one based on residual positional errors and another based on residual + intrafraction positional errors from the imaging data obtained in a dual imaging environment. A total of 22 lung cancer patients were included in this study. For primary image guidance, four-dimensional cone beam computed tomography (4-D CBCT) was used and stereoscopic ExacTrac was used as the auxiliary imaging. Following table position correction (TPC) based on the initial 4-D CBCT, another 4-D CBCT (post-TPC) and a pair of stereoscopic ExacTrac images were obtained. Further, during the treatment delivery, a series of ExacTrac images were acquired to identify the intrafraction PE. If a, b and c were the observed translational shifts in lateral (x-axis), longitudinal (y-axis) and vertical direction (z-axis) and α, β and γ were the rotational shifts in radians about the same axes, respectively, then the resultant translational vectors (A, B and C) were calculated on the basis of translational and rotational values. Set-up margins were calculated using residual errors post-TPC only and also using intrafraction positional errors in addition to the residual errors. Residual and residual + intrafraction SM were calculated from a dataset of 82 CBCTs and 189 ExacTrac imaging sessions. CBCT-based mean ± SD shifts in translational and rotational directions were 0.3 ± 1.8mm, 0.1 ± 1.8mm, - 0.4 ± 1.6mm, 0.1 ± 0.4°, 0.0 ± 1.0° and 0.3 ± 0.7°, respectively, and for ExacTrac - 0.1 ± 1.8mm, 0.2 ± 2.4mm, - 0.6 ± 1.8mm, 0.1 ± 1.2°, - 0.2 ± 1.3° and - 0.1 ± 0.6°, respectively. Residual SM without considering the rotational correction in x, y and z directions were 5.0mm, 4.5mm and 4.4mm; rotation-corrected SM were 4.4mm, 4.0mm and 5.5mm, respectively. Residual plus intrafraction SM were 5.5mm, 6.6mm and 6.2mm without considering the rotational corrections, whereas they were 5.0mm, 6.3mm and 6.2mm with rotational errors accounted for. Accurate calculation of set-up margin is required to find the clinical to planning target volume margin. Primary and auxiliary imaging margins fall in the range of 4.0 to 5.5mm and 5.0 to 7.0mm, respectively, indicating a higher SM for X-ray-based planar imaging techniques over three-dimensional cone beam images. This study established the degree of mutual compatibility between two different kinds of widely used set-up imaging modalities, on-board CBCT and in-room stereoscopic imaging ExacTrac. It also describes the technique to calculate the residual and residual plus intrafraction SM and its variation in a dual imaging environment accounting for rotational PE in stereotactic body radiotherapy of lung.

Rotational Doppler Frequency Shift from Time‐Evolving High‐Order Pancharatnam–Berry Phase: A Metasurface Approach

AbstractThe Doppler frequency shift of sound or electromagnetic waves has been widely investigated in many different contexts and, nowadays, represents a formidable tool in medicine, engineering, astrophysics, and optics. Such effect is commonly described in the framework of the universal energy‐momentum conservation law. In particular, the rotational Doppler effect has been recently demonstrated using light carrying orbital angular momentum. When a wave undergoes a cyclic adiabatic transformation of its Hamiltonian, it is known to acquire the so‐called Pancharatnam–Berry (PB) phase. In this work, an experimental evidence of the direct connection between the high‐order PB phase time evolution on the Poincaré sphere and the rotational Doppler frequency shift of light is provided. A metasurface operating at telecom wavelengths is employed to impose a total (spin and orbital) angular momentum (TAM) on the light wave, while two TAM converters ensure a closed cycle on the Poincaré sphere. By rotating one of the converters, a significant Doppler frequency shift is observed without variation of the output TAM. The proposed metasurface‐based approach offers new advanced ways to engineer the frequency content of light.

The vicious circle between physical, psychological, and physiological characteristics of shift work in nurses: a multidimensional approach.

To compare physical, psychological, and physiological adaptations between rotating and morning shift health workers using objective and subjective approaches. Forty nurses [n = 20 morning shift (MS) group; n = 20 rotating shift (RS) group] were evaluated for anthropometry, body composition, and handgrip strength. Quality of life, depression, fatigue, daytime sleepiness, and sleep quality were assessed with SF-36, Zung Self-Rating Depression Scale (SDS), Fatigue Severity Scale (FSS), Epworth Sleepiness Scale(ESS), and Pittsburgh Sleep Quality Index (PSQI), respectively. Physical activity was assessed by the International Physical Activity Questionnaire (IPAQ) and triaxial accelerometers. Sleep-related data were monitored with sleep actigraphy. Salivary melatonin levels were analyzed before/after sleep, and blood lipid profiles were measured the following morning. The RS group had higher mean BMI and total and abdominal fat and scored lower in the SF-36 (p < 0.01). All nurses showed reduced physical activity levels, which, in the RS group, were negatively correlated with FSS (p = 0.033) and SDS scores (p = 0.025). Poor sleep was revealed in 53% of nurses. The RS group had worse sleep quality by PSQI than the MS group (p = 0.045). PSQI scores were inversely related to SF-36 scores and positively correlated with FSS, BMI, waist circumference, and body fat (p < 0.05). RS nurses showed increased body mass and total and abdominal fat along with decreased quality of life and sleep quality compared to MS counterparts. A strong relationship was found between physical, psychological, and physiological domains. Further studies should consider workplace interventions to prevent obesity, promote physical activity, and manage poor sleeping patterns in nurses.

The courses of objective physical activity and the association with sleepiness during a 2-week-on/2-week-off offshore shift rotation: an observational repeated-measures study

BackgroundOffshore workers are assumed to have poor health behaviours, but no studies have yet examined physical activity (PA) during a full offshore shift rotation period, including both work and at home periods. Furthermore, the relationship of PA with sleepiness, a prevalent safety hazard offshore, is not known. This study aimed to examine (1) the courses of objectively measured PA in offshore workers during pre-, offshore and post-offshore periods, and (2) the association between PA and self-reported sleepiness.MethodsAn observational repeated measures study was conducted among 36 offshore workers during a full 2-week on/2-week off offshore shift rotation. Objective PA was assessed using Daytime Activity Averages (DAA) from actigraph recordings. Sleepiness was assessed using next-morning Karolinska Sleepiness Scale (KSS) scores. The courses of PA over time were analysed with Linear Mixed Models (LMM). Parallel LMM were used to assess the longitudinal relationship between PA and sleepiness, both on a between-person and within-person level.ResultsThe courses of PA were not significantly different between the pre-, offshore, and post-offshore periods. In addition, between-person trends of PA and sleepiness were not associated (p ranges between 0.08─0.99) and PA did not affect next-morning sleepiness on a within-person level (p = 0.15).ConclusionsPA levels during the offshore working period were not different from PA levels at home. Furthermore, PA was not associated with next-morning sleepiness. Further research should focus on different levels of PA including its intensity level.

Factors associated with the risk subclinical carotid atherosclerosis in rotational shift workers in the Arctic

Objective.To determine the most unfavorable predictors of atherosclerotic plaque (ASP) in carotid arteries (CA) in rotational shift workers in the Arctic using traditional risk factors, clinical and instrumental methods of research.Design and methods. In 2010–2012, we randomly selected 424 males aged 30–59 years from 1708 rotational shift workers at the medical unit of the gas production company “Gazprom dobycha Yamburg” (Yamburg settlement, 68ºN) and performed preventive medical examination. Subjects were divided into 2 groups according to blood pressure (BP) level. Group 1 included 294 patients with hypertension (HTN) of 1 or 2 stages &gt; 140/90 mmHg and group 2 was comprised of 130 people with BP &lt; 140/90 mmHg. The groups did not differ by age, total work experience in the Arctic and rotational shiftwork duration. Ultrasound examination of CA showed presence or absence of ASP and stenosis by NASCET method. In addition, we assessed traditional risk factors and performed 24-hour BP monitoring and blood tests including lipid spectrum, glucose level, creatinine.Results.ASP was found more often in subjects with HTN (group 1) than in people with normal BP in the same age group, 95 % CI 56–60 % vs 95 % CI 14–20 %, (p &lt; 0,0001). The groups did not differ significantly in the nutritional habits (p = 0,067). At the same time, the rate of smoking (p = 0,039), low physical activity (p = 0,007), overweight (p &lt; 0,0001) was significantly higher in group 1 compared to subjects with normal BP. According to multivariate analysis, three variables with the most significant predictors associated with ASP in CA with sensitivity 75,9 % were selected using step-by-step method: diastolic BP 24 (DBP24) (p &lt; 0,0001), glucose (p = 0,017) and total cholesterol (p = 0,044). The linear function was obtained: F = –7,664 + 0,225 × Chol + 0,366 × Glu + 0,057 × DBP24, where the variable “Chol” is the level of total cholesterol in the blood in mmol/l; “Glu” — the level of blood glucose in mmol/l; “DBP24” — average 24-hour diastolic BP. Based on the model, we concluded that DBP24 increment by 1 mmHg increases the risk for developing ASB in CA by 5,9 %, OR = 1,059 (95 % CI: 1,033; 1,087); the increment in glucose and total cholesterol by 1 mmol/l increases the risk by 44,1 % and 25,2 %, respectively: OR = 1,441 (95 % CI: 1,084; 1,966), OR = 1,252 (95 % CI: 1,010; 1,565).Conclusions.Our data enable to determine the most unfavorable predictors of ASP in CA and can potentially serve as a guideline for early diagnosis and medical management to prevent cardiovascular diseases in rotational shift workers in the Arctic.

ARTERIAL HYPERTENSION RISK PREDICTION IN CONDITIONS OF ROTATIONAL SHIFTWORK IN THE ARCTIC

Objective: To study features and dynamics of chronostructure of circadian blood pressure (BP) rhythm in normotensive patients and define their prognostic value with respect to arterial hypertension (AH) within prospective observation in conditions of Arctic rotational shiftwork. Design and method: During the prospective one-year study, in conditions of rotational shiftwork in the Arctic, 173 men with normal BP and with negative history of AH (mean age 40.2 ± 4.1 years) were examined. Work experience in the Arctic was 16.5 ± 6.8 years; work experience in rotational shifts was 11.2 ± 3.8 years and office BP was 123.4 ± 7.5/80.5 ± 5.5. All patients underwent ambulatory blood pressure monitoring (ABPM) 1 time in 3 months; individual cosinor-data analysis was carried out to determine circadian rhythm chronotypes. Results: According to the classification of P. Cugini, true normotension (50%) and atypical chronotypes: allonormotension (22%) and isonormotonia (28%) were revealed in individuals with normal BP. The prognostic value of circadian BP rhythm disturbances was explained by high frequency of atypical normotensive chronotype transformation into hypertensive ones. During the year of observation, AH developed in 26% of normotonics with atypical chronotypes. Based on results of the study of chronobiological parameters in individuals with normal BP, the role of autonomic nervous system in the formation of chronotypes of circadian BP rhythm in normotensive patients was assessed. Moreover, atypical chronotypes of BP highlighted as main disturbances of circadian rhythm in the conditions of the Arctic region. Atypical normotensive chronotypes were characterized by more evident structural changes of the heart and vessels. In conditions of the Arctic, chronobiological approach in comparison with standard analysis of ABPM indicated higher diagnostic sensitivity, specificity and efficiency. Logistic regression revealed prognostic significance of normotensive atypical chronotypes compared to main risk factors (smoking, low physical activity, body mass index, dyslipidemia, age, duration of work in the Arctic and rotational shiftwork experience, the mode and type of rotational shiftwork). Conclusions: Using multivariant analysis, there was received the model for determining a diagnostic indicator showing risk for AH development during one-year observation in normotensive individuals in condition of rotational shiftwork in the Arctic.

Association of industrial work schedules with development of metabolic syndrome, insulin resistance, and serum adipokine concentrations.

Association of work schedule in industrial workers with the progression of metabolic syndrome, insulin resistance, and serum adipokine concentrations is incompletely explored. To determine the association of work schedule with the progression of metabolic syndrome, insulin resistance, and adipokine concentrations in industrial workers. In a cross-sectional study design of industrial workers we compared metabolic syndrome, insulin resistance, and adipokines concentration between workers in the day shift (n = 52), rotational shift (n = 21), and night shift (n = 15). The international Diabetes Federation criteria were used to diagnose metabolic syndrome. We used a homeostatic model assessment of insulin resistance (HOMA-IR). Serum insulin, leptin, and adiponectin concentrations were measured using enzyme-linked immunosorbent assays. Serum glucose, triglyceride, and high-density lipoprotein cholesterol (HDL-C) concentrations were monitored using Prietest clinical chemistry reagents. The proportional difference in metabolic syndrome (0.31, 95% confidence interval [CI] 0.036-0.587, P = 0.026), median difference of leptin (0.61, 95% CI 0.186-1.034, P = 0.005), and leptin-to-adiponectin ratio (LAR; 0.45, 95% CI 0.235-0.665, P < 0.001) was significantly higher, and serum adiponectin was lower (-2.00, 95% CI -4.197 to 0.197, P = 0.07) in the night-shift workers compared with that of day-shift workers. Among rotational-shift workers, the proportional difference between metabolic syndrome (0.14, 95% CI -0.098 to 0.378, P = 0.25), median difference of leptin (0.25, 95% CI -0.124 to 0.624, P = 0.19), and LAR (0.09, 95% CI -0.099 to 0.279, P = 0.35) was higher, and serum adiponectin concentration was lower (-0.73, 95% CI -2.660 to 1.208, P = 0.46) compared with that of day-shift workers; however, the altered differences were not significant. We observed a higher proportion of difference in HOMA-IR in shift workers (night and rotation) than in day-shift workers. Night-shift workers are vulnerable to a higher risk of metabolic syndrome, HOMA-IR, and adipokine changes.

Association between chronotype and psychomotor performance of rotating shift workers

It is known that the chronotype potentially mediates the performance and tolerance to work in shifts and that shift rotation is associated with negative effects on psychomotor performance. This study aimed to evaluate the effect of chronotype on psychomotor performance throughout a complete shift rotation schedule. Thirty males working in clockwise rotating shifts from a mining company were evaluated under a real-life condition over the following shift schedule: 2 days of day work, 2 days of evening work and 2 days of night work. The chronotype was determined using the Munich Chronotype Questionnaire adapted for shift workers and the obtained scores were categorized by tertiles (early-type, intermediate-type and late-type). Work performance was evaluated by Psychomotor Vigilance Test (PVT) daily just before shift starts and after shift ends. Sleep duration was evaluated by actigraphy over the whole shift. No isolated effect of the shift or interaction between shift and chronotype was found in the performance variables evaluated. A significant isolated effect of the chronotype showed that the early-type individuals had higher values of pre- and post-work Mean of Reaction Time (MRT) (308.77 ± 10.03 ms and 306.37 ± 8.53 ms, respectively) than the intermediate-type (257.61 ± 6.63 ms and 252.91 ± 5.97 ms, respectively, p < 0.001) and the late-type (273.35 ± 6.96 ms and 262.88 ± 6.05 ms, respectively, p < 0.001). In addition, late individuals presented a greater number of lapses of attention (5.00 ± 0.92; p < 0.05) than early (1.94 ± 0.50, p < 0.05) and intermediate (1.33 ± 0.30, p < 0.001) ones. We concluded that, compared with intermediates, late-type workers had a greater number of lapses of attention on the shift schedule as a whole, while early-type workers showed the highest pre- and post-work MRT. These findings show that the psychomotor performance of rotating shift workers seems to be influenced by the chronotype, but not by the shift rotation.

A comparison between two different immobilization devices for radiation therapy treatment of pelvic cancer using VMAT

ObjectivesTo assess setup reproducibility of low kneefix with feetfix (LKF-FF) system and its operator-reported convenience by reference to low dual leg positioner (LDLP), among patients treated with pelvic radiotherapy. MethodsA retrospective controlled trial was carried out at the radiotherapy unit. It included patients who underwent radical radiotherapy to the pelvis using VMAT, and who benefitted from LDLP (N = 30) or LKF-FF (N = 30) immobilization system. Average absolute shifts (AAS) and total vector errors (TVE) were computed and compared between the two systems, using translational (lateral, longitudinal and vertical) and rotational (X, Y and Z planes) directions. Accuracy rates were computed on pooled data including 1529 VMAT images, 819 in LDLP and 710 in LKF-FF groups, using different cutoffs. Radiotherapists' subjective assessment of the device's ease of setup, handling, cleaning, and storage, and patient comfort was carried out comparatively between the two devices. ResultsNo statistically significant difference was observed between the two systems in systematic settings, while LKF-FF outperformed LDLP in random settings; notably in vertical translation and X and Z rotational shifts. Analysis of TVEs showed significant decrease in rotational TVE in LKF-FF group (mean=1.38° versus 2.38, p = 0.003) by reference to LDLP, respectively; however, both systems had comparable translational TVE (p = 0.590). In pooled analysis, LKF-FF enabled an overall increase in setup accuracy rates in rotational directions by up to 15% and 19% at ±1° and ±2° accuracy levels, respectively (p<0.05). Subjective assessments showed that the two immobilization systems were comparable regarding all investigated dimensions; however, the overall radiotherapists’ preference leaned toward LDLP. ConclusionThe newly implemented LKF-FF system outperformed LDLP in terms of setup reproducibility, notably in rotational directions, where it enhanced setup accuracy rates by up to 19%. Long-term use of LKF-FF may improve the users’ satisfaction.

Low-Complexity Random Rotation-Based Schemes for Intelligent Reflecting Surfaces

The employment of intelligent reflecting surfaces (IRSs) is a potential and promising solution to increase the spectral and energy efficiency of wireless communication networks. Despite their many advantages, IRS-aided communications have limitations as they are subject to high propagation losses. To overcome this, the phase rotation (shift) at each element needs to be designed in such a way as to increase the channel gain at the destination. However, this increases the system's complexity as well as its power consumption. In this article, we present an analytical framework for the performance of random rotation-based IRS-aided communications. Under this framework, we propose four low-complexity and energy efficient schemes, based on a coding or a selection approach. Both of these approaches employ random phase rotations and require limited knowledge of channel state information. Specifically, the coding-based schemes use time-varying random phase rotations to produce an equivalent time-varying channel. On the other hand, the selection-based schemes select a partition of the IRS elements based on the received signal power at the destination. Analytical expressions for the achieved outage probability and energy efficiency of each scheme are derived. It is demonstrated that all schemes can provide significant performance gains as well as full diversity order.

Observation of the rotational Doppler shift of the ring Airy Gaussian vortex beam

We observe the rotational Doppler shift of an orbital angular momentum-carrying ring Airy Gaussian vortex (RAiGV) beam based on the rotational Doppler effect (RDE) for the first time. The Airy Gaussian beam has attracted a considerable interest in recent years owing to its autofocusing characteristics which indicates an important potential use in optical trapping. Here we propose a scheme for spinning object detection by employing such a RAiGV beam. The RAiGV beam is prepared by a spatial light modulator. An experiment scheme is proposed in a superposition light system, and the results show that the RAiGV has the same well performance in spinning speed detection with other optical vortex beams. It is also found that by varying the scale factor and ring radius of the RAiGV beam, the intensity profile varies accordingly, as well as the autofocusing distance. Especially, we find that a larger scale factor leads to a higher SNR, while as the ring radius changes, the signals are almost not affected. Furthermore, the RDE signal can be recognized with high accuracy even at the autofocusing position, which is confirmed through repeating the measurement along the propagation path of the RAiGV beam. The results of this work may find useful applications in Doppler velocimetry, remote sensing and metrology.

Rootedness along the way: meaningful sociality in petroleum and mining mobile worker camps

ABSTRACT Rotational shift work, long-distance commuting (LDC) and fly-in/fly-out (FIFO) have become increasingly prevalent forms of labour force provision in the resource extraction sector worldwide over the last few decades. This entails the workforce being on the move, with cycles of long shifts on site and extended periods back home. This article draws on ethnographic field work carried out in Arctic Russia and Subarctic Canada among petroleum and mining workers. It focusses on sociality processes in workers’ camps. I employ the notion of ‘meaningful sociality’ among camp inhabitants, which comes about when workers experience ‘rootedness along the way’. Both notions are basic elements of a long-term and satisfactory mobile and multilocal lifestyle. This article shows how the quality of rootedness, job satisfaction and wellbeing in such a labour setting are highly dependent on intersectional conditions of equality at interpersonal and politico-economic scales. Corporations are called upon to actively facilitate the necessary material and affective camp conditions to enable meaningful sociality and provide an equity-based atmosphere for people to become rooted along their way.

Prevalence of Anti-SARS-CoV-2 Antibody in Hospital Staff in Double-Center Setting: A Preliminary Report of a Cohort Study From Iran

Background: The outbreak of COVID-19 in China in late 2019 was an unprecedented catastrophe that also involved many other countries, including Iran. Concerning the danger of disease contagion, it is necessary to detect asymptomatic or mild cases, especially in hospital staff who are highly exposed to the disease. Objectives: In this serosurvey study, we aimed to estimate IgG seroprevalence among hospital staff in two public hospitals to determine local transmission and infection risk factors, as well as protective immunity among high-risk populations. Methods: Screening was offered to the hospital staff of two public hospitals in Shiraz, Iran. Screening involved the measurement of IgG antibodies against SARS-CoV-2. Besides, a checklist that consisted of questions about sociodemographic, occupational, and epidemiological characteristics was completed by the participants. Results: Among 494 participants in this study, 29 (5.8%) had anti-SARS-CoV-2 IgG in their blood. Besides, 320 (64.8%) had at least one of the clinical symptoms within six months before this survey. Among participants with positive PCR, nine (21.4%) had anti-SARS-CoV-2 IgG, while this figure was seven (33.3%) for individuals with positive CT scans. Non-proper disposal of used protective equipment or infectious wastes (OR = 26.5), rotational daily work shifts (OR = 7.5), being anxious about getting COVID-19 (OR = 3.8), and age (OR = 1.06) were the significant determinants of having anti-SARS-CoV-2 IgG in the hospital staff. Conclusions: It is essential to continue training and giving technical consultations about COVID-19, especially the proper disposal of used protective equipment or infectious wastes in rotational daily shift workers.

Shifted Firefighter Health Investigation by Personal Health Insurance Record in Taiwan.

IntroductionTaiwan’s firefighters use a shift rotation system with 2 days of work and 1 day of rest. Numerous papers have already explored the risks of shift work to the body. However, little data concern the impact of shift work on health as reflected in medical visits. This study used individuals’ medical visit record in Taiwan’s health insurance system. The locally called “health bank” contains individuals’ medical visit record, health insurance payment points and the medicine used.MethodsConsent was obtained from 150 firefighters who were serving under the shift rotation system to obtain their 2015 individual “My Health Bank” medical data. Comparisons were made between national health insurance data norm.ResultsFirefighters make significantly more visits for Western medicine than the annual average (firefighters 6.27 vs norm 5.24, P = 0.04142), more total number of medical visits (9.57 vs 7.75, P = 0.0102), more annual average payment points for Western medicine (4079 vs 2741, P = 0.003151), and a greater average number of total annual medical visit points (7003 vs 4940, p = 0.0003157). Firefighters had significantly higher incidents of respiratory diseases, urogenital diseases, skin and subcutaneous tissue diseases, musculoskeletal system and connective tissue diseases, injuries, and illness from poisoning than did the norm (P<0.05).ConclusionA persuasive health-survey-based method for workers in high occupational hazard industries was proposed in this study, and the result was highly correlated with risk factors of fireworkers. The proposed study method is potential to investigate risk factors of other working.

Observation of the rotational Doppler shift with spatially incoherent light

The rotational Doppler shift (RDS) is typically measured by illuminating a rotating target with a laser prepared in a simple, known orbital angular momentum (OAM) superposition. We establish theoretically and experimentally that detecting the rotational Doppler shift does not require the incident light to have a well-defined OAM spectrum but instead requires well-defined correlations within the OAM spectrum. We demonstrate measurement of the rotational Doppler shift using spatially incoherent light.

How low can you go? A CBCT dose reduction study.

PurposeCone beam computed tomography (CBCT) is often used for patient setup based solely on bony anatomy. The goal of this work was to evaluate whether CBCT dose can be lowered to the level of kV image pair doses when used for bony anatomy‐based IGRT without compromising positioning accuracy.MethodsAn anthropomorphic phantom was CT scanned in the head, head and neck, chest, and pelvis regions and setup on the linear accelerator couch with the isocenter near the planned location. Cone beam computed tomographies were performed with the standard “full dose” protocol supplied by the linac vendor. With sequentially lowering the dose, three‐dimensional (3D) matching was performed for each without shifting the couch. The standard kV image pair protocol for each site was also used to image the phantoms. For all studies, six degrees of freedom was included in the 2D or 3D matching to the extent they could be employed. Imaging doses were determined in air at isocenter following the TG‐61 formalism.ResultsCone beam computed tomography dose was reduced by 81–98% of the standard CBCT protocol to nearly that of the standard kV image pair dose for each site. Relative to the standard CBCT shift values, translational shifts were within 0.3 and 1.6 mm for all sites, for the reduced dose CBCT and kV image pair, respectively. Rotational shifts were within 0.2 degree and 0.7 degrees for all sites, for the reduced dose CBCTs and kV image pair, respectively.ConclusionFor bony anatomy‐based image guidance, CBCT dose can be reduced to a value similar to that of a kV image pair with similar or better patient positioning accuracy than kV image pair alignment. Where rotations are important to correct, CBCT will be superior to orthogonal kV imaging without significantly increased imaging dose. This is especially important for image guidance for pediatric patient treatments.

Whatever happened to the 'Goodwin pattern'?

The 'Goodwin pattern' -- an anti-clockwise rotation in real activity x wage share space recurring at intervals that correspond roughly to the duration of business cycles -- is an enduring feature of high-frequency dynamics in capitalist economies. It is well known that the centre or focus of this rotation shifts over time. More recently, however, the Goodwin pattern seems to have broken down, the wage share no longer increasing as the real economy improves over the course of short-term booms. In this paper, the breakdown of the Goodwin pattern is associated with the consolidation of an `incomes policy based on fear' that is part-and-parcel of neoliberalism. As a result of this in- comes policy based on fear, the institutional structure of the labour market disciplines labour at any rate of unemployment. This decouples wage-share dynamics from the state of the real economy, with the result that as recently witnessed, the wage share is rendered invariant to tightening of the labour market in the course of short-term cyclical booms.

A field investigation of the relationship between rotating shifts, sleep, mental health and physical activity of Australian paramedics

Paramedics working on a rotating shift are at an increased risk of developing chronic health issues due to continuous circadian rhythm disruption. The acute effects of shift rotation and objectively measured sleep have rarely been reported in paramedics. This study investigated the relationships between a rotating shift schedule and sleep (using actigraphy), subjective reports of sleepiness, mood, stress and fatigue. Galvanic Skin Response, energy expenditure and physical activity (BodyMedia SenseWear Armband) were also recorded across the shift schedule. Paramedics were monitored for a period of eight consecutive days across pre-shift, day shift, night shift, and 2 days off. Fifteen paramedics (M age = 39.5 and SD = 10.7 years) who worked rotational shifts experienced sleep restriction during night shift compared to pre-shift, day shift and days off (p < 0.001). Night shift was also associated with higher levels of stress (p < 0.05), fatigue (p < 0.05), and sleepiness (p < 0.05). One day off was related to a return to pre-shift functioning. Such shift-related issues have a compounding negative impact on an already stressful occupation with high rates of physical and mental health issues. Therefore, there is an urgent need to investigate methods to reduce rotating shift burden on the health of paramedics. This could be through further research aimed at providing recommendations for shift work schedules with sufficient periods for sleep and recovery from stress.

Feasibility and Significance of Dose Adaptation via Linear Couch Translations to Correct for Rotational Shifts During Frameless Brain Radiosurgery with the Gamma Knife Icon™.

The present study aimed to examine the technical feasibility and effectiveness of adapting the radiation dose distributions with three-dimensional (3D) linear couch translations in contrast to full six-dimensional couch maneuvers to correct for rotational shifts during frameless radiosurgical treatment with the Gamma Knife Icon™ (Elekta AB; Stockholm, Sweden). The original magnetic resonance images used for radiosurgery treatment planning (15 targets) were digitally processed to simulate rotational shifts of ±1, ±2, ±3, ±5, and ±10 degrees in the transverse plane and imported back into Leksell GammaPlan® (Elekta AB), creating "uncorrected" treatment plans. In addition, geometrically optimized 3D translation shifts were consequently applied to each isocenter in all "uncorrected" treatment plans to account for systematically introduced rotational shifts and to produce "corrected" treatment plans. The differences in the dose distribution between the original treatment plans and the "uncorrected" and "corrected" treatment plans were calculated and compared at each rotational shift position. The "uncorrected" treatment plans resulted in a significant deterioration in target coverage (by 8-72%) and selectivity (by 2-42%), with some targets being missed completely with rotations of ±3 or more degrees. In contrast, in all "corrected" treatment plans, the average decreases in target coverage and selectivity were only 1% (maximum values 4-5%). Applications of 3D linear couch translations successfully overcome gross uncertainties in dose distributions caused by up to ±10 degrees of rotational shifts in a target. As a result, rapid dose adaptation with 3D couch translations is unique and effective for frameless radiosurgery with the Gamma Knife Icon™.