Cyclic Changes Research Articles

Assessment of hydraulic and thermal properties of the Antarctic active layer: Insights from laboratory column experiments and inverse modeling

To better understand the changes in the hydrologic cycle caused by global warming in Antarctica, it is crucial to improve our understanding of the groundwater flow system, which has received less attention despite its significance. Both hydraulic and thermal properties of the active layer, through which groundwater can flow during thawing seasons, are essential to quantify the groundwater flow system. However, there has been insufficient information on the Antarctic active layer. The goal of this study was to estimate the hydraulic and thermal properties of Antarctic soils through laboratory column experiments and inverse modeling. The column experiments were conducted with sediments collected from two lakes in the Barton Peninsula, Antarctica. A sand column was also operated for comparison. Inverse modeling using HydroGeoSphere (HGS) combined with Parameter ESTimation (PEST) was performed with data collected from the column experiments, including permeameter tests, saturation-drain tests, and freeze-thaw tests. Hydraulic parameters (i.e., Ks, θs, Swr, α, β, and Ss) and thermal diffusivity (D) of the soils were derived from water retention curves and temperature curves with depth, respectively. The hydraulic properties of the Antarctic soil samples, estimated through inverse modeling, were 1.6 × 10−5–3.4 × 10−4 cm s−1 for Ks, 0.37–0.42 for θs, 6.62 × 10−3–1.05 × 10−2 for Swr, 0.53–0.58 cm−1 for α, 5.75–7.96 for β, and 5.11 × 10−5–9.02 × 10−5 cm−1 for Ss. The thermal diffusivities for the soils were estimated to be 0.65–4.64 cm2 min−1. The soil hydraulic and thermal properties reflected the physical and ecological characteristics of their lake environments. The results of this study can provide a basis for groundwater-surface water interaction in polar regions, which is governed by variably-saturated flow and freeze-thaw processes.

Cyclical ‘wetting’ phenomenon in the source region of Yellow River under long-term trends from 1956 to 2022

Study regionthe source region of the Yellow River (SRYB) Study focusDue to environmental changes, the drying and wetting processes have become increasingly intricate, and it is uncertain whether the wetting phenomenon in the SRYB indicates a long-term trend or a temporary cyclic event. This study utilized monthly streamflow and precipitation records from 1956 to 2022 to calculate hydrological and meteorological-dryness/wetness, represented by the standardized streamflow and precipitation indices, respectively. This study used detrended, wavelet, and cross-wavelet methods to investigate dry-wet variability and identified the atmospheric circulation phenomena driving the dryness/wetness and cyclical changes in the region. New hydro-meteorological insights for the SRYB(i) The SRYB showed an overall fluctuating wetting trend, which intensified after 2000. (ii) There were notable oscillatory cycles at 3–5 years, 10–12 years, and approximately 20–25 years in both hydrological and meteorological dry-wet variability. (iii) Transitions from dry to wet conditions had no significant link to short-term cycles (e.g., 3–5 years), but were linked to decadal cycles (e.g., 20–25 years). (iv) Spring and winter precipitation and streamflow dominated the interannual dry-wet variability. (v) The ENSO, AMO, and PDO influenced short-term cyclic fluctuations, while the AO and PDO influenced decadal cyclic fluctuations. This indicates that the wetting trend follows a cyclic pattern, and the intensification since 2000 is consistent with a decadal cyclic signal.

Study of Different Method of Plastic Waste Management in the Light of Ecosystem Balance

The present study is related to different method of plastic waste management in the light of ecosystem balance. Plastic waste has become a major environmental concern, causing pollution in both land and marine ecosystems. As a result, plastic debris is accumulating in landfills and natural environments instead of decomposing. This accumulation is causing various environmental hazards and negatively impacting habitats and species distribution. To address this issue, researchers have been focusing on finding effective methods of plastic waste management that promote ecosystem balance. These methods include microbial agents and their metabolic enzymes for polymer degradation and destructive thermal treatments like combustion or pyrolysis. In addition, different countries have implemented varying waste management strategies to tackle plastic pollution. Indiscriminate use of plastics such as polyethylene causes environmental pollution and impacts human health due to irreversible changes in the ecological cycle. The future of plastic waste management research lies in the continuous innovation of recycling technologies, the development of environmentally friendly alternatives, and the integration of social and behavioural considerations in waste management strategies. By addressing these areas, research can contribute to the advancement of sustainable and effective solutions for plastic waste handling, furthering the goal of achieving ecosystem balance and minimizing environmental harm. A comprehensive assessment of plastic management strategies should consider their environmental, economic, and social implications to gauge their overall effectiveness in addressing the challenges of plastic waste. This multifaceted approach will provide a holistic understanding of the impact of plastic waste management efforts and guide future decision-making to further enhance the sustainability and effectiveness of plastic waste handling..

Urban Environmental Planning in Shimla Smart City: Review of Related Literature

Urban environmental concerns are on rise due to increasing population pressure on finite natural resources, deforestation, over grazing, unplanned construction, networking of roads and large-scale modification of natural landscape. It has caused irreversible damage to the ecology of this Himalayan state. Number of ultra modern projects, road networking, hydropower projects, and SEZ and real estate projects are costing Himalayan ecology. Unplanned developmental activities and urban processes in city have resulted in several ecological problems like environmental pollution, noise pollution extreme climatic conditions, shortage of drinking water, landslides, sinking land and change in seasonal cycle. Poor urban planning will cause social, economic and environmental implications in long term. Cities needs to be planned professionally keeping in mind future sustainability. Before planning a city in hilly areas, needs proper understanding of complex and dynamic phenomena involving interaction between environmental and socio- economic and political factors with multi disciplinary approach and vision. Urbanization and industrialization on one side is contributing its share in economic development of a region but on the other hand, it is degenerating water, air, soil and natural resources resulting in the degradation of environmental quality (Anjum, 1998). Urban environmental degradation leaves direct impact on the ecology and causes ecological imbalance (Singh, 1996). The most striking reason for the environmental degradation is the changing man and environment relationship. (Dasman, 1976), Shah (2001). Developmental activities in Himalayan region need different treatment and systematic planning.

Assessing the Impact of Oral Isotretinoin on the Menstrual Cycle: A Prospective Study on Predictors of Menstrual Irregularities.

Background and Objectives: This study aims to evaluate the association between the use of oral isotretinoin and menstrual irregularities in acne patients with previously regular menstrual cycles. Materials and Methods: A prospective observational study was conducted on 58,599 female patients aged 14 to 36 at King Abdullah University Hospital in Irbid, Jordan. The patients were followed for a period of 4.5 to 8 months during treatment and for 2 months post-treatment. Menstrual cycle changes were documented, and statistical analysis was performed to identify any significant associations. Results: A total of 111 (37.1%) patients, who were previously known to have regular menstrual cycles, complained of menstrual changes while using oral isotretinoin. Ninety-nine of those patients who complained of menstrual changes had their cycles back to normal post-treatment. There is a significant difference in the total accumulative dose between those with changes in menses and those without; p-value [0.008]. The most common change that occurred was amenorrhea (p < 0.001), followed by oligomenorrhea and menorrhagia (p < 0.001 and p = 0.050, respectively). The duration of treatment was a significant predictor of menstrual irregularities, with an odds ratio (OR) of 5.106 (95% CI: 1.371-19.020, p = 0.015), indicating a higher likelihood of menstrual changes with increased treatment duration. The total accumulative dose was also significantly associated with menstrual irregularities (OR = 0.964; 95% CI: 0.939-0.990; p = 0.006). Additionally, a family history of PCOS significantly increased the odds of menstrual irregularities (OR = 3.783; 95% CI: 1.314-10.892; p = 0.014). Conclusions: The study identified that 37.1% of the participants experienced changes in their menstrual cycles while undergoing isotretinoin therapy, with the vast majority (89.2%) returning to normal within two months post-treatment. Our logistic regression analysis pinpointed the duration of isotretinoin treatment, the total accumulative dose, and a family history of PCOS as significant predictors of menstrual irregularities.

Impact of Climate Change on the Environment: A Synthesis Study

Climate change has a significant impact on both physical and social components of the environment. Every component of the environment has been suffering the impacts of climate change. All components of the environment are interrelated through the exchanging of energy and matter; hence they actively interact. Major components of the environment like the biosphere, lithosphere, atmosphere, and hydrosphere are open systems to impact climate change. This paper describes the major impacts of climate change on major components of the environment. This study investigated the current state, wide-range global research trends, and different concerns on the impacts of climate change on the sustainable tourism. Global climate change represents a grand challenge for society, one that is increasingly influencing tourism sector investment, planning, operations, and demand. This study synthesized a total of 36 studies on climate change by sourcing published material from the review that was performed in indexed databases namely Dimensions, Web Science, Elsevier Scopus, and Google Scholar. Therefore, the study found that human beings are the major contributors to climate change through anthropogenic greenhouse gas emissions that worsened during the Green Revolution. Climate change outcomes through the loss of valuable ecosystem goods and services, degrading the most of keystone species sites. In other ways, loss of biodiversity, changes in atmospheric composition, changes in chemical reactions in soil, changes in water quality, availability, and hydrologic cycles, and frequent occurrence of extreme weather conditions. Of course! The effects of climate change are wide-ranging and diverse, impacting many areas and facets of daily life. Therefore, this study recommends implementing carbon pricing mechanisms to internalize the costs of greenhouse gas emissions and enforcing stringent environmental regulations and standards to limit emissions and pollution. Support global efforts and agreements to combat climate change, such as the Paris Agreement.

A photometric study of a total-eclipse contact binary V458 Mon

We present light curve solution of V458 Mon firstly by using the Wilson-Devinney code. The total eclipse and deep minima of the light curves of V458 Monenable us to determine reliable orbital parameters of the binary system. The solution suggests that V458 Monis a low mass ratio binary system with about 0.2 possessing a moderate degree of contact. The long-term period investigation showed that the period of V458 Monis increasing at dP/dt=+2.59×10−7days/yr, which could be the reason of mass transfer from the less massive component to more massive primary one, together with a periodic change. The oscillation in orbital period may be due to an unseen tertiary companion with the mass about M3=1.8M⊙ . After removing these change, there is still a weak cyclic change maybe due to magnetic activity. With the increase in orbital period of binary, the separation increases and mass ratio decreases which eventually leads V458 Montowards merger.

Abnormal Uterine Bleeding following by COVID-19 Vaccine

Background: After the COVID-19 vaccination, concerns about side effects were rised globally. One of the reported side effects was changes in menstrual periods. In this study, we aimed to evaluate changes in the menstrual cycle, including frequency, length, abnormal bleeding, and pain after the COVID-19 vaccine.

A study of the dynamic relationship between the RMB exchange rate, foreign exchange reserves and monetary policy

In today's globalized economic environment, the relationship between China's RMB exchange rate, foreign exchange reserves and monetary policy has become more and more complex, and is crucial to the stability and sustainable development of the economy. The interactions among these three have a direct impact on China's macroeconomic situation, so it has become a very urgent task to study this relationship in depth. This study combines theoretical and empirical research to deeply analyze the dynamic relationship among these three, aiming to provide practical guidance for the formulation of China's monetary policy.This paper selects the time series data of RMB exchange rate, foreign exchange reserves and money supply from 2003 to 2023 to study the relationship between RMB exchange rate, foreign exchange reserves and monetary policy. This paper will deeply explore the impact of the government's market intervention on the RMB exchange rate under different exchange rate regimes, especially under the fixed exchange rate regime and the floating exchange rate regime. This paper will delve into the transmission mechanism of monetary policy, especially the flexibility and adaptability of monetary policy under the volatility of global financial markets and changes in economic cycles. In terms of empirical research, this paper will use the VAR model and the GARCH model for time series analysis to verify the applicability of the theoretical mechanism in practical situations and provide lessons for the formulation of future monetary policy.

PERMANENT JUNCTIONAL RECIPROCATING TACHYCARDIA: IT IS IMPORTANT TO KNOW HOW TO RECOGNIZE IT

Abstract Permanent junctional reciprocating tachycardia, also known as Coumel‘s tachycardia, is a rare form of supraventricular tachycardia that is usually incessant, characterised by retrograde conduction via an accessory pathway usually located in the posteroseptal region with slow and decremental conduction. Tachycardia is virtually incessant, at a rate ranging from 120 to 250 beats/minute. The electrocardiogram inscribes inverted P waves in leads II, III, AVF, as well as left lateral leads, along with a P–R interval shorter than the R–P interval during the tachycardia. The characteristic, but not diagnostic, electrocardiographic feature is a long R–P interval consistent with slow retrograde conduction. Spontaneous resolution of tachycardia is not un common. Electrocardiographically, it manifests as a narrow QRS tachycardia with long RP‘, with negative retrograde “p” waves in lower leads (D2, D3 and avF). The initiation and termination of the arrhythmia is not determined by a premature beat, but by critical changes in the RR cycle, that is, for values of the heart rate at which the activating front finds the retrograde decremental pathway outside refractoriness. Due to its incessant characteristic in some cases, patients may present tachycardiomyopathy, with myocardial dilation and ventricular dysfunction. We report the case of a 5–year–old girl who came in for onset of heart palpitation for several hours. On electrocardiogram finding of supraventricular tachycardia, narrow QRS, HR 170/min, negative p waves in DII–DIII–AVF. The electrocardiographic finding was compatible with a picture of permanent junctional reciprocating tachycardia. Following the administration of 50mg of phleicanide, there is a progressive reduction in heart rate until the clinical picture stabilizes. antiarrhythmic therapy was subsequently set with subsequent re–evaluation and discharge to the patient‘s home.

Research progress in regulation of hair growth by dermal adipose tissue

To summarize the dynamic and synchronized changes between the hair cycle and dermal adipose tissue as well as the impact of dermal adipose tissue on hair growth, and to provide a new research idea for the clinical treatment of hair loss. An extensive review of relevant literature both domestic and international was conducted, analyzing and summarizing the impact of dermal adipose precursor cells, mature dermal adipocytes, and the processes of adipogenesis in dermal adipose tissue on the transition of hair cycle phases. Dermal adipose tissue is anatomically adjacent to hair follicles and closely related to the changes in the hair cycle. The proliferation and differentiation of dermal adipose precursor cells promote the transition of hair cycle from telogen to anagen, while mature adipocytes can accelerate the transition from anagen to catagen of the hair cycle by expressing signaling molecules, with adipogenesis in dermal adipose tissue and hair cycle transition signaling coexistence. Dermal adipose tissue affects the transition of the hair cycle and regulates hair growth by secreting various signaling molecules. However, the quantity and depth of existing literature are far from sufficient to fully elucidate its prominent role in regulating the hair cycle, and the specific regulatory mechanisms needs to be further studied.

Analysis of extreme precipitation variation characteristics in mountain grasslands of arid and semi-arid regions in China

Introduction: With global warming, the disaster losses caused by extreme precipitation events are increasing. The poor natural conditions and climate change make the arid and semi-arid mountainous grassland area a sensitive region of climate change. The study on the spatio-temporal variation characteristics of extreme precipitation events in this region is helpful to improve the ability of climate prediction and disaster prevention and reduction in grassland.Methods: Based on the daily precipitation data of four meteorological monitoring stations in the Yinshanbeilu from 1970 to 2020, the trend analysis, M-K test and wavelet analysis were used to select seven typical extreme precipitation indicators to analyze the temporal and spatial characteristics of extreme precipitation.Results and Discussion: The results showed that the precipitation in the Yinshanbeilu increased in the past 51a, and the number of heavy rain days increased significantly. The significance test of CDD and CWD showed that the number of continuous dry days and continuous wet days decreased abruptly. The spatial analysis showed that the high value areas of R95p, R95d and PRCRTOT were all located in Siziwang Banner, and it could be concluded that the extreme precipitation risk was the highest in Siziwang Banner, while the low value areas of SDII, Rx1day, R95p and PRCRTOT were all located in Sonid Right Banner, which could be inferred that the Sonid Right Banner was relatively dry. The first main cycle of the seven indexes of extreme precipitation almost runs through the whole time series, and the starting point of the minimum main cycle changes inconsistent. In addition to the number of consecutive dry days, the other indices have a good correlation with annual precipitation, flood season and monthly precipitation from June to September, and July is the peak period of extreme precipitation events.

Human-induced intensified seasonal cycle of sea surface temperature

Changes in the seasonal cycle of sea surface temperature (SST) have far-reaching ecological and societal implications. Previous studies have found an intensified SST seasonal cycle under global warming, but whether such changes have emerged in historical records remains largely unknown. Here, we reveal that the SST seasonal cycle globally has intensified by 3.9 ± 1.6% in recent four decades (1983–2022), with hotspot regions such as the northern subpolar gyres experiencing an intensification of up to 10%. Increased greenhouse gases are the primary driver of this intensification, and decreased anthropogenic aerosols also contribute. These changes in anthropogenic emissions lead to shallower mixed layer depths, reducing the thermal inertia of upper ocean and enhancing the seasonality of SST. In addition, the direct impacts of increased ocean heat uptake and suppressed seasonal amplitude of surface heat flux also contribute in the North Pacific and North Atlantic. The temperature seasonal cycle is intensified not only at the ocean surface, but throughout the mixed layer. The ramifications of this intensified SST seasonal cycle extend to the seasonal variation in upper-ocean oxygenation, a critical factor for most ocean ecosystems.

Vibration energy harvesting system with cyclically time-varying potential barrier

Nonlinear kinetic energy harvesters are becoming more and more popular as well as advanced and efficient. This paper presents the study of the dynamics of such a system in a wide range of excitation parameters, assuming at the same time the possibility of a cyclical and smooth change of the potential function. We have designed a system that allows to obtain a wide spectrum of potential characteristics, from a single well to a three-well system, and we have analyzed its effectiveness. Next, we checked the influence of parameters characterizing the change of potential using bifurcation diagrams and their comparison with the effective voltage values. We also analyzed the behavior of the system in chaotic and periodic motion zones and presented selected sections of Poincare and Fourier amplitude-frequency spectra of chaotic solutions. The last element of the analysis was the impact of cyclic potential change on coexisting solutions. We have shown that the best effectiveness is achieved when the frequency of the external load is equal to the resonant frequency of the flexible cantilever beam and the change of potential is limited to extreme positions.

Statistical analysis of the development of the plant production industry by the example of changes in the average yield of grain crops in the XX century. Part 1. Period 1900 - 1933.

The work is devoted to studying the development of the crop production industry in the twentieth century. The theory of cyclical production and change of technological structures is chosen as a working theory. The average yield of grain crops in the Russian Empire and the Russian Soviet Federative Socialist Republic was determined to indicate production development. The choice of average grain yield is justified by its 'vital role in agriculture in the specified period. The change in the studied indicator is considered in the period from 1900 to 1933. The work provides a 'visual, graphical, historical, and statistical analysis of changes in the average yield of grain crops. The period from 1900 to 1933 is proposed to be divided into smaller periods consisting of H years, defined as small. For each small period, a statistical analysis is carried out, which includes calculating probabilistic characteristics, checking the average yield values for abnormal values, the presence of changes in the indicator during the period, and the nature of this change. Dividing the time interval into small periods allows us to study the change in yield in more detail and identify factors influencing this process. For each period, a hypothesis is put forward about the type of changes, and the acceptance or non-acceptance of the hypothesis is justified. The statistical analysis results are considered within the framework of past events identified during historical analysis. Building a model of changes in average yield during the period under review allows us to assess the industry’s past development and suggest possible future development scenarios. Analyzing the results of a statistical study in combination with historical context will provide a deeper understanding of the reasons for changes in yields and their impact on the development of the industry.

Subalpine peatland development since the Last Glacial Maximum in subtropical China: Predominantly controlled by monsoonal climate and local topography

Peatlands interact significantly with the global carbon cycle and climate changes. A comprehensive understanding of the development of peatlands is extremely important to help address future climate challenges. Here, we combine three total organic carbon content records with seven published records from subalpine peatlands in the monsoonal region of subtropical China, aiming to reveal the general pattern of peatland development since the Last Glacial Maximum (LGM) in this region. The synthesis showed that organic carbon contents significantly increased at approximately 16 cal kyr B.P. These ten records clearly display two distinct patterns since that time: pattern one showed three intervals of high carbon contents at ca. 16−12 cal kyr B.P., 9.5−7.5 cal kyr B.P. and 6−4 (or 4−1) cal kyr B.P., whereas pattern two reached the maximum in the early Holocene and remained high and relatively stable during the Holocene. Through comparison with pollen indicators and climate reconstructions, we demonstrated that local hydrology linked to monsoonal climates (especially precipitation) was the dominant factor controlling carbon accumulation and the development of subalpine peatlands since the LGM in subtropical China. However, two dynamic patterns that occurred under the same climatic conditions were attributed to the significant modulation of local topography, i.e., intermontane basin (pattern one) or montane (pattern two) settings. The hydrology and development of peatlands are functions of the changes in monsoonal climate and local site-specific topography. These findings provide a comprehensive understanding of past long-term development of peatlands under monsoonal climates.

The role of menstrual cycle changes in the evaluation of women's reproductive, sexual and mental health - lessons learned from the covid-19 pandemic

The role of menstrual cycle changes in the evaluation of women's reproductive, sexual and mental health - lessons learned from the covid-19 pandemic

Cuproptosis is involved in decabromodiphenyl ether-induced ovarian dysfunction and the protective effect of melatonin

Decabromodiphenyl ether (BDE-209) has been universally detected in environmental media and animals, but its damage to ovarian function and mechanism is still unclear, and melatonin has been shown to improve mammalian ovarian function. This study aimed to investigate the toxic effects of BDE-209 on the ovary and tried to improve ovarian function with melatonin. Herein, BDE-209 was administered orally to female SD rats for 60 days. Enzyme-linked immunosorbent assay, HE staining, transcriptome analysis, qPCR and immunohistochemical staining were used to explore and verify the potential mechanism. We found that BDE-209 exposure had effects on the ovary, as shown by abnormal changes in the estrous cycle, hormone levels and ovarian reserve function in rats, while increasing the proportion of collagen fibres in ovarian tissue. In terms of mechanism, cuproptosis, a form of cell death, was identified to play a crucial role in BDE-209-induced ovarian dysfunction, with the phenotype manifested as copper salt accumulation in ovary, downregulation of glutathione pathway metabolism and copper transfer molecule (ATP7A/B), and upregulation of FDX1, lipoic acid pathway (LIAS, LIPT1), pyruvate dehydrogenase complex components (DLAT, PDHB, PDHA1), and copper transfer molecule (SLC31A1). Furthermore, possible interventions were explored. Notably, a supplement with melatonin has a repair effect on the damage to ovarian function by reversing the gene expression of cuproptosis-involved molecules. Overall, this study revealed that cuproptosis is involved in BDE-209-induced ovarian damage and the beneficial effect of melatonin on ovarian copper damage, providing evidence for the prevention and control of female reproductive damage induced by BDE-209.

Chronicling menstrual cycle patterns across the reproductive lifespan with real-world data

The intricate hormonal and physiological changes of the menstrual cycle can influence health on a daily basis. Although prior studies have helped improve our understanding of the menstrual cycle, they often lack diversity in the populations included, sample size, and the span of reproductive and life stages. This paper aims to describe the dynamic differences in menstrual cycle characteristics and associated symptoms by age in a large global cohort of period-tracking application users. This work aims to contribute to our knowledge and understanding of female physiology at varying stages of reproductive aging. This cohort study included self-reported menstrual cycle and symptom information in a sample of Flo application users aged 18–55. Cycle and period length and their variability, and frequency of menstrual cycle symptom logs are described by the age of the user. Based on data logged by over 19 million global users of the Flo app, the length of the menstrual cycle and period show clear age-associated patterns. With higher age, cycles tend to get shorter (Cycle length: D¯\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$${\\overline{\ ext{D}}}$$\\end{document} = 1.85 days, Cohen’s D = 0.59) and more variable (Cycle length SD: D¯\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$${\\overline{\ ext{D}}}$$\\end{document} = 0.42 days, Cohen’s D = 0.09), until close to the chronological age (40–44) suggesting menopausal transition, when both cycles and periods become longer (Cycle length: D¯\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$${\\overline{\ ext{D}}}$$\\end{document} = 0.86 days, t = 48.85, Cohen’s D = 0.26; Period length: D¯\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$${\\overline{\ ext{D}}}$$\\end{document} = 0.08, t = 15.6, Cohen’s D = 0.07) and more variable (Cycle length SD: D¯\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$${\\overline{\ ext{D}}}$$\\end{document} = 2.80 days, t = 111.43, d = 0.51; Period length SD: D¯\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$${\\overline{\ ext{D}}}$$\\end{document} = 0.23 days, t = 67.81, Cohen’s D = 0.31). The proportion of individuals with irregular cycles was highest in participants aged 51–55 (44.7%), and lowest in the 36–40 age group (28.3%). The spectrum of common menstrual cycle-related symptoms also varies with age. The frequency of logging of cramps and acne is lower in older participants, while logs of headache, backache, stress, and insomnia are higher in older users. Other symptoms show different patterns, such as breast tenderness and fatigue peaking between the ages of 20–40, or mood swings being most frequently logged in the youngest and oldest users. The menstrual cycle and related symptoms are not static throughout the lifespan. Understanding these age-related differences in cycle characteristics and symptoms is essential in understanding how best to care for and improve the daily experience for menstruators across the reproductive life span.

Full life cycle changes of low impacted mandibular third molar associated cystic lesions and adjacent tooth root resorption: a retrospective study

ObjectiveLow impacted third molars are usually asymptomatic and are often found by X-ray examination. The removal of asymptomatic low impacted third molars is one of the most controversial clinical issues in oral and maxillofacial surgery.MethodsIn this study, 806 patients with low impacted mandibular third molars (LIMTMs) (full bony impaction) were analyzed to determine the prevalence and risk factors for cystic lesions and adjacent tooth root resorption throughout the patients’ entire life cycle.ResultsThe results showed that the prevalence of adjacent tooth root resorption and cystic lesions was age-related, exhibiting a trend of first increasing and then decreasing; prevalence peaked at the age of 41 to 45 years old, the prevalence rates were 12.50% and 11.11% respectively. And the lowest prevalence rate was 2.86% and 2.44% in ≥ 61 group and 56- to 60-year age group respectively. Age was an independent risk factor for adjacent tooth root resorption of LIMTMs, whereas age and impaction type (especially inverted impaction) were independent risk factors for cystic lesions.ConclusionsThe full life cycle management strategy for LIMTMs may need to be individualized. Surgical removal is recommended for LIMTMs in patients younger than 41 to 45 years, especially for inverted, mesioangular, and horizontally impacted LIMTMs. LIMTMs in patients older than 41 to 45 years may be treated conservatively with regular follow-up, but surgical removal of inverted impacted LIMTMs is still recommended to avoid cyst formation.