Periodic Shifts Research Articles

Estimation of the Impact of Climate Warming on Spring Wheat (Triticum aestivum L.) Phenology From Observations and Modelling in the Arid Region of Northwest China

ABSTRACTClimate warming has induced shifts in the phenological period and thus affected cultivar selection and effective crop management. Particularly, the great climate warming in the dry environment could have more effects on the phenology of spring wheat with the distinct cycle of biological events during growth. In this study, the daily observations of spring wheat phenology and meteorology from 1991 to 2018 were used to analyse changes in phenology concerning accumulated temperature in the Hexi Corridor region of Northwest China. Five crop growth models (WheatGrow, WOFOST, CropSyst, CERES‐Wheat and APSIM‐Wheat) were selected to evaluate the reliability of the phenological stage simulations in the study region. Results show that in the past 28 years, the annual accumulated temperature in the whole growth period from sowing to maturity increased by 3.08°C–8.35°C/a at three sites of the region. Climate warming shortened the phenological period at rates of 3.56–4.49 days/10a, mostly attributed to the shortened duration from anthesis to maturity. Statistical analysis demonstrated that the shortened phenological period cannot be simply expressed by the linear correlation between the length of phenological phases and accumulated temperature in the respective growth stages. The five wheat growth models after parameter validation can generally capture the phenological dates, and WOFOST performed best at the three sites. However, when the calibrated model was used for simulations of long‐term variations of phenological dates, the accumulated errors in simulations could result in large deviations of the predicted physiological change to the observations.

Un/veiling the Maharani: Autobiography as Medium and Metaphor for Royal Women’s Self-Fashioning in the Indian Princely States

This article examines two royal women’s autobiographies—The Autobiography of an Indian Princess (1921) by Sunity Devi and Maharani: The Story of an Indian Princess (1953) by Brinda Devi, queen consorts in the princely states of Cooch Behar and Kapurthala, respectively—to study their employment of the literary genre of autobiography as a site for self-fashioning in the context of the emergent public sphere in India. Locating them at the intersection of multiple historical shifts in the late colonial period, the article aims to trace their negotiations of power through self-fashioning in a socio-political context in which they were both privileged (as royalty) and marginalised (as colonial subjects and women in a patriarchal structure). In doing so, it posits the motif of ‘un/veiling’ as central to the royal women’s autobiographical self-representation and argues how it is metaphorical of the larger act of self-fashioning performed by them in public.

Experimental investigation of the radial structure of energetic particle driven GAM in TCV

Abstract High amplitude energetic particle geodesic acoustic mode (EGAM) oscillations driven by Neutral Beam (NBI) injected in the direction counter to the toroidal plasma current are observed in the TCV tokamak. The modes appear at frequencies close to the geodesic acoustic mode (GAM) frequency, corresponding to the mode radii calculated without plasma elongation corrections. The spatial structure of the EGAM density oscillation is analyzed using multichannel soft x-ray (SXR) and broadband light emission diagnostics. The analysis of spatiotemporal emission data shows a non-rotating structure of the density oscillations. The non-rotating mode discrimination is the additional new capability of the multichannel spatiotemporal SXR data analysis technique in TCV. We present the discrimination method of assessing the standing character of the EGAM wave. The structure of EGAM density oscillations in TCV is consistent with the theoretical GAM poloidal structure, namely a m= 1 standing wave with density oscillations amplitude proportional to sin(θ), where the poloidal angle θ is measured from the equatorial plane. The poloidal structure of magnetic the field oscillations is analyzed using a poloidal array of magnetic coils. The structure of the EGAM-induced magnetic field oscillations in TCV is a m = 2 standing wave. Time evolution of EGAMs suggests that a nonlinear EGAM chirping is observed. The chirping depends on the EGAM radial location, which varies as the NBI deposition is varied through a vertical shift of the plasma magnetic axis. The chirping disappears at the plasma periphery. A fast periodic radial shift of the EGAMs radial location is also observed to occur during the single chirp.

Determinants of Work Fatigue in Inpatient Nurses at RSI Siti Hajar Sidoarjo

Introduction: Nurses are an important part of patient care so they are often required to provide optimal service which sometimes causes fatigue. With different individual characteristics of each worker such as age and physical condition of workers and job characteristics such as length of service and duration of work, it is possible to experience fatigue at different levels of fatigue. Objective: To determine the relationship between age, work period, and work shifts with work fatigue in inpatient nurses at RSI Siti Hajar Sidoarjo and identify the relationship between age with work fatigue, work period with work fatigue, work shifts with work fatigue in inpatient nurses at RSI Siti Hajar Sidoarjo. Method: This type of research is quantitative with random sampling technique. Data collectin was carried out with IFRC (Industrial Fatigue Research Committee) questionnaire instrument on 125 inpatient nurses at RSI Siti Hajar Sidoarjo. The bivariate analysis process is carried out by testing the data with the SPSS program using the Spearman Rank Correlation test. Result: The majority of inpatient nurses who have the potential to work fatigue are ?35 years old, had worked for ?5 years, working on the morning shift, experienced low fatigue and the majority of nurses felt thirsty, wanted to lay down after work, often yawned, sleepy, and tired all over. Based on the hypothesis test, between age and fatigue was obtained sig. 0.002 < 0.05, between tenure and fatigue obtained sig. 0.001 < 0.05, and between work shifts and work fatigue obtained sig. 0.032 < 0.05. Conclusion: There is a relationship between age, length of service, work shifts with work fatigue in inpatient nurses at RSI Siti Hajar Sidoarjo.

Missed infection prevention and control activities and their predictors: insights from a pre- and post-pandemic study

The primary aim of this study was to compare differences, if any, in missed infection prevention and control (IPC) activities before and after the pandemic, along with the related predictors. The secondary aim was to identify relationships between missed IPC activities and unfinished nursing care. A repeated cross-sectional design was conducted in 2019 (pre-pandemic, 184 nurses) and 2024 (post-pandemic, 240 nurses) in a large academic hospital following the Checklist for Reporting of Survey Studies guidelines. The Missed Nursing Care in Infection Prevention and Control Survey (MNC-IPC) (Part A: missed activities, Part B: reasons), the Unfinished Nursing Care Survey (UNCS), and professional data were collected homogeneously across both periods. Self-reported missed IPC activities decreased from 2.15 out of 5 (95% confidence interval (CI), 2.05-2.25) to 1.51 (95% CI, 1.45-1.58) (P<0.0005), as did the related reasons, which decreased from 2.35 out of 4 (95% CI, 2.24-2.46) to 2.20 (95% CI, 2.11-2.30) (P=0.046). The total variance in the MNC-IPC overall scores was explained by 22.8% (pre-) and 20.7% (post-pandemic) by different predictors: system-level issues (estimated value 0.409, P=0.008) and nurses' intention to leave (0.107, P=0.023) in the pre-pandemic and by the number of patients admitted in the last shift (0.015, P=0.053), organizational issues (0.186, P<0.0005) and priority-setting issues (0.092, P=0.053) in the post-pandemic period. MNC-IPC and UNCS scores have reported significant correlations in both periods. Missed IPC activities were less likely in the post-pandemic period possibly due to system efforts and lessons learned during the pandemic, which may have routinized IPC practices among nurses. Overall, predictors of missed IPC care changed after the pandemic, suggesting new patterns and the need for innovative interventions, particularly at the unit level and targeting younger nurses. The correlations between UNCS and MNC-IPC suggest that targeted improvements in one area are likely to yield positive outcomes in the other. However, despite their commonalities, these represent two distinct phenomena.

Risk factors for neurologic sequelae in children and adolescents with hemophilia after intracranial hemorrhage

BackgroundIntracranial hemorrhage (ICH) is reportedly rare but has high morbidity and mortality risk in persons with hemophilia. Although the risk factors that facilitate bleeding are known, the factors affecting the sequelae are not well known. ObjectivesWe planned to investigate the risk factors for neurologic sequelae in children and adolescents with hemophilia suffering from ICH. MethodsAn invitation was sent to pediatric hematology centers via email. Clinical and laboratory findings, neurologic sequelae, and recurrence of bleeding in persons with hemophilia who developed ICH were questioned. ResultsEighty-six patients from 21 centers were evaluated. All patients were less than 18 years of age at the time of ICH. Thirteen patients had ICH in the neonatal period, while 40 patients had a known diagnosis of hemophilia before ICH, and 33 patients were undiagnosed before ICH. Five patients died, 2 of whom died in the neonatal period. The rate of neurologic sequelae was 25 of 81 (30%). The most common neurologic sequela was epilepsy (n = 11/25), followed by hemiparesis (n = 5/25). Cerebral shift (odds ratio, 3.48) and development of ICH in the neonatal period (odds ratio, 4.67) were significant for the development of neurologic sequelae in multivariate analysis. On follow-up, recurrence of ICH occurred in 8 of 81 (10%). ConclusionICH in the neonatal period and cerebral shift were the two main risk factors for the development of neurologic sequelae. Neonatal departments must be alert to the signs of bleeding. It is important for healthcare professionals to overcome the barriers to primary prophylaxis and to take trauma-related precautions.

The Effects of Climate Change on Kenya’s Economic Growth

Changes in the climate and natural disasters have hampered Kenya's growth in economy, as seen by periodic droughts, floods, and shifts in rainfall and temperature patterns. The research investigated the effects of climatic change on Kenya's GDP growth. Modeling was done using Autoregressive Distributed Lag (ARDL) model estimation technique while analyzing data from 1990 to 2023. Climate change was represented by annual rainfall fluctuations, carbon emissions, and forest depletion, with inflation, exchange rates, and government spending serving as the controlling factors. The regression results indicated that at 5% level of significance short run carbon emissions affect growth negatively but the long run results indicated a positive effect. Forest depletion positively impacts growth in the long run period. Government expenditure, changes in the exchange rate and economic growth had an inverse relationship. Inflation did not have potential long term impact on GDP. This study recommended that the government to balance economic growth with environmental sustainability by promoting cleaner technologies and renewable energy projects. Investments advanced irrigation and drought resistant crops are crucial. Sustainable forest management should involve controlled logging and reforestation to ensure long term health. Reducing exchange rate volatility through foreign reserves and diversified exports will stabilize the economy. Enhancing government expenditure efficiency by focusing on high return investments and minimizing waste will boost GDP stability.

Existence of forced waves and gap formations for a Lotka-Volterra competition system with nonlocal dispersal in a time periodic shift habitat

This paper is devoted to the study of a class of time periodic Lotka-Volterra competition system with nonlocal dispersal and shifting habitats. By using some known results of the periodic KPP model and employing the iterative techniques, we prove that there exist two positive numbers $c_{0}(d_{1})$ and $c_{0}(d_{2})$ such that the system admits a forced wave provided that the forcing speed $c\in(-c_{0}(d_{2}),c_{0}(d_{1}))$. In addition, based on the theoretical results, we show that the gap formations exist for $c&gt;c_{0}(d_{1})$ and $c&lt;-c_{0}(d_{2})$.

Mechanisms of Reappeared Period Shifts of Internal Solitary Waves Based on Mooring Array Observations in the Northern South China Sea

AbstractMooring observations have revealed that the daily reappeared time (DRt) of internal solitary waves (ISWs) in the northern South China Sea (SCS) manifests systematic shifts. This study aims to reveal the dynamic mechanisms behind this phenomenon using the theory of modulation of shear flow to the internal tide wave (IT) propagation. Approximate solutions for the frequency modulation function (FMF) and the amplitude modulation function (AMF) of ITs are derived and validated by the mooring array measurements on the northern SCS continental shelf in 2019 and 2020. Namely, the mechanisms of the ISW reappeared period shift (RPS derived from DRt) and amplitude variation are attributed to the modulation of low‐frequency flow with a period of about 7 days to ITs. The FMF is induced by the vorticity of the low‐frequency flow (FS1) and the Doppler shift (FS2). Thus, the sign of the FMF value may be positive (blue shift) and negative (red shift), depending on the algebraic summation of the two terms. The FS2 derived from mooring observed velocities confirms the modulation effects of mean current on the frequency shift and the amplitude variation of ITs and ISWs.

The Molecular and Biological Patterns Underlying Sustained SARS-CoV-2 Circulation in the Human Population

For four years, SARS-CoV-2, the etiological agent of COVID-19, has been circulating among humans. By the end of the second year, an absence of immunologically naive individuals was observed, attributable to extensive immunization efforts and natural viral exposure. This study focuses on delineating the molecular and biological patterns that facilitate the persistence of SARS-CoV-2, thereby informing predictions on the epidemiological trajectory of COVID-19 toward refining pandemic countermeasures. The aim of this study was to describe the molecular biological patterns identified that contribute to the persistence of the virus in the human population. For over three years since the beginning of the COVID-19 pandemic, molecular genetic monitoring of SARS-CoV-2 has been conducted, which included the collection of nasopharyngeal swabs from infected individuals, assessment of viral load, and subsequent whole-genome sequencing. We discerned dominant genetic lineages correlated with rising disease incidence. We scrutinized amino acid substitutions across SARS-CoV-2 proteins and quantified viral loads in swab samples from patients with emerging COVID-19 variants. Our findings suggest a model of viral persistence characterized by 1) periodic serotype shifts causing substantial diminutions in serum virus-neutralizing activity (> 10-fold), 2) serotype-specific accrual of point mutations in the receptor-binding domain (RBD) to modestly circumvent neutralizing antibodies and enhance receptor affinity, and 3) a gradually increasing amount of virus being shed in mucosal surfaces within a single serotype. This model aptly accounts for the dynamics of COVID-19 incidence in Moscow. For a comprehensive understanding of these dynamics, acquiring population-level data on immune tension and antibody neutralization relative to genetic lineage compositions is essential.

Modern epidemiological features of viral acute intestinal infections in children and adolescents of Sakhalin region

Objective: to identify modern epidemiological features of viral acute intestinal infections in children and adolescents in the Sakhalin Region.Materials and methods. Data on acute intestinal infection incidence obtained from statistical reports of the Rospotrebnadzor during 2021-2023 was compared with long-term average incidence rates calculated over the period before the COVID-19 pandemic (2010-2019) to perform epidemiological analysis. Incidence was calculated for different age groups; according to months of the year, monthly long-term average incidence rates were established. Index of seasonality, coefficient of seasonality, and index of seasonal growth were determined.Results and discussion. Manifestations of acute intestinal infections epidemic process in the Sakhalin Region indicate persisting conditions for an increase in the registration of both sporadic cases of diseases and outbreaks of infectious diarrhea. Viruses were prevailing in the structure of cases of known etiology (mainly caused by rotaviruses and noroviruses). Their intra-annual dynamics showed changes in rotavirus and norovirus infection incidence rates: a shift in periods of increased incidence, a decrease in the coefficient of seasonality, and for rotavirus infection, a decrease in the index of seasonal growth. Age-adjusted rotavirus infection incidence showed predominance of the infection among preschool-aged children; norovirus infection was frequently detected among schoolchildren and adolescents. An increase in the focality index may indicate ongoing problems in the public catering sector, non-compliance with sanitary rules and hygiene standards, and untimely detection and isolation of patients with acute intestinal infections.Conclusion. Obtained results confirm the epidemiological significance of viral gastroenteritis and the necessity of anti-epidemic measures optimization.

Assessing the Settlement and Deformation of Pile-Supported Embankments Undergoing Groundwater-Level Fluctuations: An Experimental and Simulation Study

The intensification of extreme weather phenomena, ranging from torrential downpours to protracted dry spells, which trigger fluctuations at the groundwater level, poses a grave threat to the stability of embankments, giving rise to an array of concerns including cracking and differential settlement. Consequently, it is crucial to embark on research targeted at uncovering the settlement and deformation behaviors of pile-supported embankments amidst changes in water levels. In tackling this dilemma, a series of direct shear tests were carried out across a range of wet–dry cyclic conditions. The results confirmed that the occurrence of wet–dry cycles significantly impacted the resilience of silty clay. Additionally, it was observed that the erosion of cohesion and the angle of internal friction initially diminished sharply, subsequently leveling off, with the first wet–dry cycle exerting the most substantial influence on soil strength. Employing a holistic pile-supported embankment model, simulations revealed that variations in the groundwater level, fluctuations therein, varying descent rates, and periodic shifts in the groundwater level could all prompt alterations in soil settlement between embankment piles and could augment the peak tensile stress applied to geogrids. In summary, the orthogonal experimental method was utilized, indicating that, in terms of impacting embankment settlement under periodic water-level changes, the factors ranked in descending order were the following: pile spacing, pile length, embankment height, and the height of the groundwater table.

Sea level and East Asian winter monsoon-controlled periodic transition of sinks in fine-grained sediments in the East China sea over the past 200 kyr

The study of critical geological processes of sediments from source to sink in the East China Sea (ECS) is of great significance for further understanding the surface processes, material cycling, and sedimentary evolution in the East Asian continental margin. Based on the high-resolution clay mineralogy and REEs in fine-grained sediments of Core CSHC-15, this study has analyzed the periodic transition mechanism of sinks in fine-grained sediments in the ECS from a source-to-sink perspective. The clay mineral provenances of Core CSHC-15 exhibited distinct periodic abrupt shifts between the Changjiang and Taiwan island over the past 200 kyr, indicating the periodic transitions of sinks in fine-grained sediments between the inner shelf of the ECS and the Okinawa Trough. When the sea level rose or fell to a critical depth (around −25 m or −50 m), the changes in the accommodation space of the continental shelf and the shelf fronts were the direct factors leading to the periodic transitions of sinks in fine-grained sediments in the ECS. The intense eccentricity cycles (100-kyr) of the clay mineral parameters of Core CSHC-15 reflected the impacts of the East Asian Winter Monsoon (EAWM). This study confirms that long-term (eccentricity and longer cycles) climate signals of the source areas can be extracted from the clastic sedimentary records of the ECS. The new finding highlights the periodic transition mechanism of sedimentary sinks in the ECS that will promote the progress of sedimentary geology since the Late Quaternary.

The Determinan of Work Fatigue of Nurses in Inpatient Room at Hospital X Pekanbaru

Nurses are at high risk on fatigue during working. This fatigue effect can be a danger to patient safety and affect the quality of hospital service. A short survey showed some nurses complained of fatigue symptoms such as decreased concentration, yawning, headache, and fatigue throughout the body. This study aims to analyze the work fatigue of nurses in X Hospital Pekanbaru by analyzing the relationship between working period, lighting, nutritional status, and work shifts as well as the dominant factors that affect work fatigue. This study was quantitative analytic with a cross-sectional design. The sample of this study was 60 people (total sampling). Data analysis using chi-square and logistic regression. The results of this study found that affecting the work fatigue of nurses in X Hospital Pekanbaru was lighting and nutritional status. The dominant factor that influences the work fatigue of nurses is lighting. The hospital is recommended to improve the quality of lighting in the workplace, especially inpatient rooms, with efforts to provide adequate lighting by PERMENKES standard No. 7 in 2019 which is equal to 250 lux.

Clock-Line-Mediated Sisyphus Cooling.

We demonstrate subrecoil Sisyphus cooling using the long-lived ^{3}P_{0} clock state in alkaline-earth-like ytterbium. A 1388-nm optical standing wave nearly resonant with the ^{3}P_{0}→^{3}D_{1} transition creates a spatially periodic light shift of the ^{3}P_{0} clock state. Following excitation on the ultranarrow clock transition, we observe Sisyphus cooling in this potential, as the light shift is correlated with excitation to ^{3}D_{1} and subsequent spontaneous decay to the ^{1}S_{0} ground state. We observe that cooling enhances the loading efficiency of atoms into a 759-nm magic-wavelength one-dimensional (1D) optical lattice, as compared to standard Doppler cooling on the ^{1}S_{0}→^{3}P_{1} transition. Sisyphus cooling yields temperatures below 200nK in the weakly confined, transverse dimensions of the 1D optical lattice. These lower temperatures improve optical lattice clocks by facilitating the use of shallow lattices with reduced light shifts while retaining large atom numbers to reduce the quantum projection noise. This Sisyphus cooling can be pulsed or continuous and is applicable to a range of quantum metrology applications.

Prevalence and factors associated with poor sleep quality among nurses in COVID-19 wards

The COVID-19 pandemic has significantly impacted the working conditions of nurses, leading to a detrimental effect on their sleep quality. This cross-sectional study aimed to investigate the prevalence of poor sleep quality and its associated factors among nurses working in COVID-19 wards in Kermanshah, Iran. A total of 97 nurses were selected through simple random sampling from COVID-19 wards. Data was collected using a demographic information sheet and the Pittsburgh Sleep Quality Index. Descriptive and inferential statistical methods, including chi-square and multiple logistic regression, were used for data analysis. The results showed that 74.2% (n = 72) of the nurses experienced poor sleep quality. Significant associations were found between poor sleep quality and work experience (p = 0.045) as well as the type of work shift (p = 0.001). However, no significant relationships were observed between poor sleep quality and factors such as age, sex, body mass index, overtime hours per month, physical activity, or underlying diseases. The high prevalence of poor sleep quality among nurses working in COVID-19 wards underscores the necessity of implementing targeted interventions to address this issue. In this regard, in addition to periodic shift schedule changes and reductions in working hours, it is necessary to adopt purposeful measures to improve working conditions and enhance the physical and mental health of nurses. These measures may include providing sufficient human resources to reduce the workload and fatigue of nurses, appropriate scheduling of working hours, and the implementation of stress management programs.

Natural Convection Fluid Flow and Heat Transfer in a Valley-Shaped Cavity

The phenomenon of natural convection is the subject of significant research interest due to its widespread occurrence in both natural and industrial contexts. This study focuses on investigating natural convection phenomena within triangular enclosures, specifically emphasizing a valley-shaped configuration. Our research comprehensively analyses unsteady, non-dimensional time-varying convection resulting from natural fluid flow within a valley-shaped cavity, where the inclined walls serve as hot surfaces and the top wall functions as a cold surface. We explore unsteady natural convection flows in this cavity, utilizing air as the operating fluid, considering a range of Rayleigh numbers from Ra = 100 to 108. Additionally, various non-dimensional times τ, spanning from 0 to 5000, are examined, with a fixed Prandtl number (Pr = 0.71) and aspect ratio (A = 0.5). Employing a two-dimensional framework for numerical analysis, our study focuses on identifying unstable flow mechanisms characterized by different non-dimensional times, including symmetric, asymmetric, and unsteady flow patterns. The numerical results reveal that natural convection flows remain steady in the symmetric state for Rayleigh values ranging from 100 to 7 × 103. Asymmetric flow occurs when the Ra surpasses 7 × 103. Under the asymmetric condition, flow arrives in an unsteady stage before stabilizing at the fully formed stage for 7 × 103 &lt; Ra &lt; 107. This study demonstrates that periodic unsteady flows shift into chaotic situations during the transitional stage before transferring to periodic behavior in the developed stage, but the chaotic flow remains predominant in the unsteady regime with larger Rayleigh numbers. Furthermore, we present an analysis of heat transfer within the cavity, discussing and quantifying its dependence on the Rayleigh number.

The Mira discovery problem—Observations by David Fabricius in 1596 and 1609 (and by others before?): Positional accuracy, brightness, color index, and period

AbstractThe pulsating variable star Mira (o Ceti) was observed by David Fabricius (Frisia) in 1596 and 1609. We review suggested previous detections (e.g., China, Hipparchos). We analyze all Mira records from Fabricius in their historical context. Fabricius measured the separation of Mira to other stars to ±1.6−1.7′. From his texts, we derive a brightness (slightly brighter than Hamal) of ca. 1.9±0.1 mag and a color index B‐V1.3−1.4 mag (‘like Mars’) for 1596 Aug 3 (Jul.). Mira started to fainten 19 days later and was observed until mid/late Oct. We show why such a red star cannot be followed by the naked eye until ca. 6 mag: For Mira's color at disappearance and altitude from Frisia, the limit is reduced by ca. 1.0 mag. Since Fabricius connected the Mira brightening with the close‐by prograde Jupiter, he re‐detected it only 12 years later, probably shortly before a relatively bright maximum—discoveries are strongly affected by biases. A Mira period of 330.2 days is consistent with both the oldest data (from Fabricius 1596 to Hevelius 1660) and the most current data (VSX 2004–2023), so that we see no evidence for secular period or phase shifts. (We also present Fabricius' observations of P Cygni in 1602.)

Fast Fourier Transform periodic interpolation method for superposition sums in a periodic unit cell

We propose a Fast Fourier Transform based Periodic Interpolation Method (FFT-PIM), a flexible and computationally efficient approach for computing the scalar potential given by a superposition sum in a unit cell of an infinitely periodic array. Under the same umbrella, FFT-PIM allows computing the potential for 1D, 2D, and 3D periodicities for dynamic problems involving the Helmholtz potential and static problems involving Coulomb potential, including problems with and without a periodic phase shift. The computational complexity of the FFT-PIM is of O(Nlog⁡N) for N spatially coinciding sources and observer points. The FFT-PIM uses rapidly converging series representations of the Green's function serving as a kernel in the superposition sum. Based on these representations, the FFT-PIM splits the potential into its near-zone component, which includes a small number of images surrounding the unit cell of interest, and far-zone component, which includes the rest of an infinite number of images. The far-zone component is evaluated by projecting the non-uniform sources onto a sparse uniform grid, performing superposition sums on this sparse grid, and interpolating the potential from the uniform grid to the non-uniform observation points. The near-zone component is evaluated using an FFT-based method, which is adapted to efficiently handle non-uniform source-observer distributions within the periodic unit cell. The FFT-PIM can be used for a broad range of applications, such as periodic problems involving integral equations for wave propagation in electromagnetics and acoustics, micromagnetic solvers, and density functional theory solvers.

TESS Light Curves of Cataclysmic Variables. IV. A Synoptic View of Eclipsing Old Novae and Novalike Variables

Based mainly on the months-long 2 minutes time-resolution light curves observed by the Transiting Exoplanet Survey Telescope (TESS) space mission of 48 eclipsing old novae and novalike variables (commonly referred to as NLs) selected from the Ritter & Kolb catalog, a synoptic view of some basic properties of these systems is provided. The supraorbital variations exhibit a large diversity of behavior. Data taken from the literature and many additional eclipse epochs measured in the TESS and in AAVSO light curves are used to update the orbital ephemerides of 21 targets. The large majority of these suffer period variations which defy current theoretical understanding. Orbital waveforms are constructed and, if possible, their variation over time is studied, revealing some common characteristics but also substantial differences between individual systems. The dependence of the eclipse depth on the out-of-eclipse flux reveals that in all systems a fraction of the light source responsible for the out-of-eclipse variations escapes eclipse and is probably located in the outer disk regions. In systems exhibiting superhumps, both eclipse width and epoch are modulated with the accretion disk precession period. This suggests an expansion and contraction of the eclipsed light source, as well as a periodic shift of its light center as a function of the accretion disk precession phase. The dependence of the orbital and superhump waveforms on the disk precession phase is also examined but does not lead to a consistent picture. Two cataclysmic variables are newly identified as eclipsing. Attention is drawn to specific peculiarities in some of the target stars.