Remarkable Incidence Research Articles

Establishment and Validation of Prognostic Nomograms for Nonmetastatic Melanoma of the Limbs—A SEER-Based Study

Background Malignant melanoma, a highly aggressive skin cancer, has remarkable incidence and mortality nowadays. This study aims to explore prognostic factors associated with nonmetastatic cutaneous melanoma of the limbs and to develop nomograms for predicting overall survival (OS) and cancer-specific survival (CSS). Methods The study cohort was derived from the Surveillance, Epidemiology, and End Results database. Univariate Cox regression, Lasso regression, and multivariate Cox regression analyses were conducted to identify prognostic factors and construct nomograms. The receiver operating characteristic (ROC) curve, time-dependent C-index, calibration curve, decision curve analysis (DCA) and Kaplan-Meier method were used to evaluate the accuracy and clinical applicability of the nomograms. Results A total of 15,606 patients were enrolled. Multivariate analysis identified several prognostic factors for OS and CSS including age, sex, histologic type, N stage, tumor thickness, depth of invasion, mitotic rate, ulceration, surgery of primary site, systemic therapy, race, and number of lymph nodes examined. A nomogram incorporating 12 independent predictors for OS was developed, with a C-index of 0.866 (95% confidence interval [CI]: 0.858–0.874) in the training cohort and 0.853 (95% CI: 0.839–0.867) in validation. For CSS, 10 independent predictors and one related factor were included, yielding a C-index of 0.913 (95% CI: 0.903–0.923) in the training cohort and 0.922 (95% CI: 0.908–0.936) in validation. The ROC curve, time-dependent C-index, calibration curve, DCA, and K-M plot demonstrated favorable discrimination, calibration, and clinical utility. Conclusion The developed nomograms provide a precise and personalized predictive tool for risk management of patients with nonmetastatic limb melanoma.

Concepts that fit in a (Roman) hand

Abstract The Roman author Lucius Anneus Seneca (4 BC–65 AC), the main representative of Stoic philosophy in Latin literature, wrote several tragedies in verse in which the Latin noun manus ‘hand’ has a remarkable incidence, almost doubling the occurrence of other terms more related to tragic themes, such as scelus ‘crime’ or mors ‘death’. This paper is based on the hypothesis that this high frequency is linked to the concept of embodiment as well as on the metonymies and metaphors used in Seneca’s figurative language to encode abstract concepts. The occurrences of the term manus in a corpus composed of Seneca’s dramatic and philosophical texts have been analysed, paying attention to the metonymic and metaphorical contexts where it appears. As a result, it has been observed that this word can refer to multiple realities such as individuals, actions, identity, control, or power.

Colorectal cancer and the heart: Uncovering the beat of racial disparities in MACCE.

1611 Background: Due to its high prevalence, colorectal cancer (CRC) forms a considerable burden on the healthcare system. Advancements in treatment modalities like immunotherapy have led to significant improvement in the 5-year survival. This, along with the cardiotoxic therapy regimens results in a remarkable incidence of major cardiovascular and cerebrovascular events (MACCE). Thus, it becomes imperative to address the intricacies of factors including racial disparities in MACCE, as these aid with facilitating equitable management of all CRC patients. Methods: Using ICD-10 codes, patients with CRC were identified from National Inpatient Sample 2019 database. We included all-cause in-hospital mortality (ACIHM), acute myocardial infarction (AMI), atrial fibrillation (AF), cerebrovascular accident (CVA), and sudden cardiac death (SCD) as MACCE for the outcomes. Baseline characteristics including demographics, comorbidities; and MACCE outcomes were studied using chi-square for categorical or ANOVA for continuous data (statistical significance determined as p-value < 0.05) and results were stratified based on patient’s races. Results: A total sample patient population of 171,695 patients with a diagnosis of CRC were identified of which 70.71% (121,410) were White, 13.85% (23,790) were Black, 9.15% (15,720) were Hispanic, 3.23% (5,555) were Asian/Pacific Islander, 0.5% (840) were Native American, and 2.55% (4380) belonged to Other races. Substantial differences in the prevalence of comorbidities were noted with hypertension (46.32%) and renal failure (24.74%) being more common in Black patients, diabetes mellitus (37.5%) in Native American patients, and dyslipidemia (37.89%) in White patients. Upon comparison with White patients, the ACIHM was higher in Black patients with adjusted odds ratio (aOR) of 1.23 (95% CI 1.057-1.432, p = 0.007) and Asian/Pacific Islander patients with aOR of 1.359 (1.014-1.823, p = 0.04). While AMI was found to be lower in all races, as compared to White patients, AF was remarkably higher in all races. CVA was higher in Black patients as compared to White patients with aOR of 1.626 (95% CI 1.401-1.886, p < 0.001). SCD was substantially higher in Black patients with aOR 2.059 (95% CI 1.478-2.869, p < 0.001), and in Hispanic patients with aOR 1.743 (95% CI 1.1-2.761, p = 0.018), when compared to White patients. Conclusions: The study noted higher prevalence of MACCE across the board with poorer outcomes in non-White populations, which highlights the urgent need for resource allocation to improve outcomes. This has to be done in pre and post cancer treatment patients, especially in high risk populations. Additionally, the role of cardio-oncology service at every stage of management of CRC appears to be crucial.

The relationship between the cutting-edge, tool wear, and chip formation during Inconel 718 dry cutting

This study comprehensively addresses the machining of nickel alloys, focusing its attention on crucial aspects related to chip formation and tool wear. Detailed characterization of the morphology and the chip formation process was performed by analyzing parameters such as chip segmentation ratio and variables such as shear band thickness and strain rate. Additionally, a numerical model was used to quantify stresses and temperatures at the tool/chip interface and to evaluate damage, thus contributing to the understanding of the development of chip formation. A transition in chip shapes as the toothing increases is highlighted, evidenced by segmentation ratio values below 0.5, indicative of the presence of discontinuous chips. The increase in cutting-edge radius is associated with a gradual increase in the compression ratio, indicating a higher plastic energy requirement in chip formation. Numerical simulations support this theory of failure. A significant correlation of 80% was identified between flank wear and the increase in shear force oscillation amplitude, indicating that flank wear contributes to system vibration. It is also noted that the adiabatic shear bands (ASB) are narrow, revealing a marked plastic deformation in the primary shear zone. Consequently, the remarkable incidence of wear with cutting parameters on chip formation is demonstrated, affecting the cutting force amplitude and, hence, the workpiece topography.

Pharmacotherapeutic potential of walnut (Juglans spp.) in age-related neurological disorders.

Global and regional trends of population aging spotlight major public health concerns. As one of the most common adverse prognostic factors, advanced age is associated with a remarkable incidence risk of many non-communicable diseases, affecting major organ systems of the human body. Age-dependent factors and molecular processes can change the nervous system's normal function and lead to neurodegenerative disorders. Oxidative stress results from of a shift toward reactive oxygen species (ROS) production in the equilibrium between ROS generation and the antioxidant defense system. Oxidative stress and neuroinflammation caused by Amyloid-ß protein deposition in the human brain are the most likely pathogenesis of Alzheimer's disease (AD). Walnut extracts could reduce Amyloid-ß fibrillation and aggregation, indicating their beneficial effects on memory and cognition. Walnut can also improve movement disabilities in Parkinson's disease due to their antioxidant and neuroprotective effect by reducing ROS and nitric oxide (NO) generation and suppressing oxidative stress. It is noteworthy that Walnut compounds have potential antiproliferative effects on Glioblastoma (the most aggressive primary cerebral neoplasm). This effective therapeutic agent can stimulate apoptosis of glioma cells in response to oxidative stress, concurrent with preventing angiogenesis and migration of tumor cells, improving the quality of life and life expectancy of patients with glioblastoma. Antioxidant Phenolic compounds of the Walnut kernel could explain the significant anti-convulsion ability of Walnut to provide good prevention and treatment for epileptic seizures. Moreover, the anti-inflammatory effect of Walnut oil could be beneficial in treating multiple sclerosis. In this study, we review the pharmaceutical properties of Walnut in age-related neurological disorders.

Too Close for Comfort: Stigma by Association in Family Members Who Live with Relatives with Mental Illness

Stigma by association is described in qualitative research of family members who have relatives diagnosed with mental illness, depicting their sense of public shame for having these relationship ties. However, there have been relatively few empirical studies thus far, in part due to the isolation of family members affecting research recruitment. In order to address this gap, an online survey was administered to 124 family members, comparing those who live in the same home with their ill relative (n = 81) and those who do not (n = 43). A remarkable incidence of one in three family members reported experiencing stigma by association. Those living with an ill relative reported comparatively higher levels of stigma by association using an adapted questionnaire measure. Both groups experienced loneliness (moderate levels), but importantly, the cohabiting relatives perceived themselves as lacking support from friends and other family members. Correlational analyses revealed that those with heightened stigma by association reported heightened anti-mattering: that is, feeling that other people treat them as if they are insignificant and invisible. Anti-mattering was also associated with more loneliness and reduced social support. Our discussion focuses on the theme that family members who actually live with mentally ill relatives experience heightened social isolation that is under-recognized due to public stigma concerns, compounded by feeling their own lives do not matter to others. Public health implications are considered for the stigmatized family members who appear to be particularly marginalized.

Outcomes of hospitalized renal allograft transplant recipients with coronavirus disease 2019

Background The outcomes of coronavirus disease 2019 in renal-transplant recipients may differ from the general population because of chronic immunosuppression and comorbidities. The aim of this study is to provide information on the clinical characteristics and outcomes of hospitalized renal allograft transplant recipients with coronavirus disease 2019 is restricted in the Arab region. This study aims to narrow this gap. Patients and methods The study was done on 21 renal allograft transplant recipients admitted in the isolation ward of a single Egyptian center for kidney diseases and transplantation during the period from July 2020 to July 2021, all cases were analyzed regarding their clinical presentation, follow-up, workup done, management, and outcomes. Results The main clinical presentations were fever 90.5% and respiratory symptoms 66.7%, not different from the general population. Their clinical course showed remarkable incidence of acute kidney injury (57.1%) than the general population, but mortality was not (14.3%). Remdesivir was tolerable, no noticeable side effects, and did not affect graft function. Conclusion This category of patients need special care, lowering of immunosuppresion during infection, close monitoring of kidney function, and respiratory status. They can receive ventilator support and same treatment as general population, including Remdesivir and Tocilizumab. Both patient and graft survival can be achieved.

Orthopaedic Implant-Associated Staphylococcal Infections: A Critical Reappraisal of Unmet Clinical Needs Associated with the Implementation of the Best Antibiotic Choice.

Infections associated with orthopaedic implants represent a major health concern characterized by a remarkable incidence of morbidity and mortality. The wide variety of clinical scenarios encountered in the heterogeneous world of infections associated with orthopaedic implants makes the implementation of an optimal and standardized antimicrobial treatment challenging. Antibiotic bone penetration, anti-biofilm activity, long-term safety, and drug choice/dosage regimens favouring outpatient management (i.e., long-acting or oral agents) play a major role in regards to the chronic evolution of these infections. The aim of this multidisciplinary opinion article is to summarize evidence supporting the use of the different anti-staphylococcal agents in terms of microbiological and pharmacological optimization according to bone penetration, anti-biofilm activity, long-term safety, and feasibility for outpatient regimens, and to provide a useful guide for clinicians in the management of patients affected by staphylococcal infections associated with orthopaedic implants Novel long-acting lipoglycopeptides, and particularly dalbavancin, alone or in combination with rifampicin, could represent the best antibiotic choice according to real-world evidence and pharmacokinetic/pharmacodynamic properties. The implementation of a multidisciplinary taskforce and close cooperation between microbiologists and clinicians is crucial for providing the best care in this scenario.

Incidence of Kidney Stones in the United States: The Continuous National Health and Nutrition Examination Survey.

The incidence of kidney stones in the United States is currently unknown. Here, we assessed the incidence of kidney stones using recent, nationally representative data. We used the National Health and Nutrition Examination Survey (NHANES) from 2015 to 2018. During this time participants were asked, "Have you ever had a kidney stone?" and "In the past 12 months, have you passed a kidney stone?" Demographics analyzed include age, race, gender, body mass index, history of smoking, diabetes, hypertension, hypercholesterolemia and gout. Multivariable models were used to assess the independent impact of subject characteristics on kidney stone prevalence and incidence. Data were available on 10,521 participants older than age 20. The prevalence of kidney stones was 11.0% (95% CI 10.1-12.0). The 12-month incidence of kidney stones was 2.1% (95% CI 1.5-2.7), or 2,054 stones per 100,000 adults. We identified significant relationships between stone incidence and subject age, body mass index, race and history of hypertension. Here we find a substantially higher 12-month incidence of kidney stones than previous reports. We also validate known risk factors for stone prevalence as associated with incidence. The remarkable incidence and prevalence of stones is concerning and has implications for disease prevention and allocation of medical resources.

Levosimendan for Treatment of Primary Graft Dysfunction After Heart Transplantation: Optimal Timing of Application.

Primary graft dysfunction remains a serious problem after heart transplant. Pharmacological treatment with the calcium sensitizer levosimendan may be an additive treatment for primary graft dysfunction. Patients undergoing heart transplant between 2010 and 2020 were retrospectively reviewed and divided depending on postoperative treatment with (n = 41) or without (n = 109) levosimendan. Recipients who received levosi mendan were further divided with regard to timing of levosimendan application (early group: started ≤48 hours posttransplant [n = 23]; late group: started >48 hours posttransplant [n = 18]). Patients who received levosimendan treatment displayed a remarkable incidence (87.8%) of postoperative primary graft dysfunction with need for venoarterial extracorporeal membrane oxygenation and therefore often presented with perioperative morbidity. Patient with early application of levosimendan showed significantly decreased duration of venoarterial extracorporeal membrane oxygenation support (5.1 ± 3.5 days vs 12.6 ± 9.3 days in those with late application; P < .01) and decreased mortality during venoarterial extracorporeal membrane oxygenation support (0.0% vs 33.3% in early vs late group; P < .01). In addition, compared with patients with late levosimendan application, patients with early application needed fewer blood transfusions (P < .05), had shorter ventilation times (279 ± 235 vs 428 ± 293 h; P = .03), and showed a trend of reduced incidence of postoperative renal failure (69.6% vs 94.4%; P = .06). Moreover, survival analyses indicated an increased survival for patients with early start of levosimendan therapy within the first 48 hours after heart transplant (P = .09). Pharmacotherapy with levosimendan may be a promising additive in the treatment of primary graft dysfunction after heart transplant. With administration of levosimendan within the first 48 hours posttransplant, rates of successful weaning from venoarterial extracorporeal membrane oxygenation and outcomes after heart transplant were shown to increase.

Robotic chemotherapy compounding: A multicenter productivity approach.

The aim of this study is to compare productivity of the KIRO Oncology compounding robot in three hospital pharmacy departments and identify the key factors to predict and optimize automatic compounding time. The study was conducted in three hospitals. Each hospital compounding workload and workflow were analyzed. Data from the robotic compounding cycles from August 2017 to July 2018 were retrospectively obtained. Nine cycle specific parameters and five productivity indicators were analysed in each site. One-to-one differences between hospitals were evaluated. Next, a correlation analysis between cycle specific factors and productivity indicators was conducted; the factors presenting a highest correlation to automatic compounding time were used to develop a multiple regression model (afterwards validated) to predict the automatic compounding time. A total of 2795 cycles (16367 preparations) were analysed. Automatic compounding time showed a relevant positive correlation (ǀrs|>0.40) with the number of preparations, number of vials and total volume per cycle. Therefore, these cycle specific parameters were chosen as independent variables for the mathematical model. Considering cycles lasting 40 minutes or less, predictability of the model was high for all three hospitals (R2:0.81; 0.79; 0.72). Workflow differences have a remarkable incidence in the global productivity of the automated process. Total volume dosed for all preparations in a cycle is one of the variables with greater influence in automatic compounding time. Algorithms to predict automatic compounding time can be useful to help users in order to plan the cycles launched in KIRO Oncology.

Postoperative atrial fibrillation in pneumonectomy for primary lung cancer.

BackgroundThis study assessed the incidence and risk factors (RFs) of postoperative atrial fibrillation (POAF) and its impact on clinical outcomes in patients undergoing pneumonectomy for lung cancer.MethodsBetween 2013 and 2018, this monocentric retrospective study enrolled 324 consecutive pneumonectomy patients for primary lung cancer from our institution and 350 lobectomy and 349 segmentectomy cases matched by age, sex and body mass index (BMI). RF for POAF and postoperative death in pneumonectomy patients were assessed by logistic regression, and long-term outcomes after a median follow-up of 30 (range, 2–61) months by Cox proportional hazard model. Electrophysiology study (EPS) files of 30 AF patients with lung resection history were reviewed.ResultsPOAF developed more often after pneumonectomy than lobectomy and segmentectomy (23.2% vs. 6.6% vs. 1.4%, respectively; P<0.001). Among 75 pneumonectomy patients with POAF, POAF was solitary in 55 patients (73.3%) and concurrent with other complications in 3 patients (4%). POAF risk after pneumonectomy was 4 and 22 times that after lobectomy and segmentectomy, respectively, with age >60 years and left atrial diameter (LAd) ≥35 mm as independent predictors. POAF, infection and hemorrhage were independent RFs for perioperative death after pneumonectomy; however, POAF was not RF for long-term death. Pulmonary vein (PV) trigger was identified in 60% (18/30) of AF patients with lung resection history, with stump PVs being more active than non-stump PVs (38.2% vs. 10.5%, P<0.001).ConclusionsPost-pneumonectomy AF, with remarkable incidence, risk and independent predictors including age >60 years and LAd ≥35 mm, was mostly solitary and possibly secondary to stump and non-stump PV triggers. POAF, along with infection and hemorrhage, was a RF for perioperative death.

Factors affecting disease recurrence in advanced stage Oral Cavity Squamous Cell Carcinoma Treated with surgery and postoperative radiotherapy.

Background: Squamous cell carcinoma of the oral cavity has a remarkable incidence worldwide with fairly onerous recurrence, encouraging further research on factors that might modify disease outcomes. Oral cancer, especially cheek is the most common cancers in Pakistan. The TNM classification is used clinically to define therapy and estimate its response and prognosis. However, in reality, it not reflects a precise impact on prognosis. Tumors associated with the same stage of this classification can show different disease progression.

Bone Mineral Density among adolescent's patients with β-thalassemia major.

Background: Beta-thalassemia is an autosomal recessive hemoglobinopathy with frequent skeletal complications, often debilitating in adolescent patients. We aim to evaluate the bone mineral density (BMD) by dual-energy x-ray absorptiometry (DEXA) and ascertain osteoporosis/osteopenia frequency in patients with β-thalassemia major.&#x0D; Methodology: In this cross-sectional study, 36 adolescent patients with β-thalassemia major were enrolled from June 2015 to March 2017. BMD was measured in the anteroposterior lumbar spine (L1-L4) and femoral neck by DEXA. For the biochemical estimations, blood and urine samples were obtained and analyzed. The results of a bone density test were presented as T and Z scores.&#x0D; Results: There were 20 male and 16 female patients with a mean age of 21.33 ± 3.7 years. The mean bone mineral content (BMC) was 20.10 ± 6.0 gm, and the mean BMD was 0.65 ± 0.07 gm/cm2. The mean T score was -3.17 ± 1.04, and the Z score was -3.06 ± 1.06. All patients had low BMD, as depicted by their T or Z scores. The reported frequency of osteoporosis and osteopenia was 77.7% and 22.2%, respectively.&#x0D; Conclusion: All Beta-thalassemia major patients had low BMD with a remarkable incidence of osteoporosis. It is recommended to perform an annual BMD among thalassemic patients to prevent fatal consequences and achieve an optimal bone density among such patients.

Therapeutic anticoagulation for venous thromboembolism after recent brain surgery: Evaluating the risk of intracranial hemorrhage

ObjectiveVenous thromboembolism (VTE) is particularly prevalent in neurosurgical patients. A major dilemma arises when a patient needs to be treated with therapeutic anticoagulation during the early days after brain surgery due to the concern of intracranial hemorrhage (ICH). There is still a lack of studies regarding the optimal time to start therapeutic anticoagulation and risk assessment of ICH in this setting. This study aims to assess the risk of ICH for patients with venous thromboembolism treated with therapeutic anticoagulation started within the first 30 days after intracranial neurosurgical procedure. Patients and methodsThis study was an analytical observational research based on a retrospective record review of VTE patients submitted to therapeutic anticoagulation started within the first 30 days after intracranial neurosurgical procedure at Paulo Niemeyer State Brain Institute, from September 2013 to February 2020. Patients’ clinical and surgical data, anticoagulation drug therapy, time interval between surgery and start of therapeutic anticoagulation, bleeding complications and hemorrhage-related deaths were some of variables evaluated. A p value < 0.05 was considered statistically significant. ResultsA series of 53 consecutive patients and 54 intracranial neurosurgical procedures met the criteria. Twenty-nine (53.7 %) patients were treated with warfarin, 21 (38.9 %) with new oral anticoagulant (NOAC) and 4 (7.4 %) only with enoxaparin. VTE diagnosis between the postoperative days 0 and 4 was statistically associated with a delay in starting therapeutic anticoagulation of more than two days (p < 0.001). The frequency of bleeding complication was statistically significant higher in patients treated with warfarin (p = 0.03). Although with no statistical significance, there were a higher rate of ICH in patients receiving warfarin (13.8 % vs. 0% in NOAC group, p = 0.13). There was no statistical difference about ICH incidence between the postoperative intervals from 2nd to 7th, 8th to 14th, 15th to 21 st and 22th to 29th days (p = 0.35). Hemorrhage-related mortality rate was 3.7 %. ConclusionICH was not statistically associated with the timing of therapeutic anticoagulation after brain surgery between the 2nd and 29th postoperative days, which may encourage the strategy of early treatment considering the life-threatening potential of VTE. However, the risk of ICH should not be ignored in the setting of warfarin use, which had a remarkable incidence of 13.8 %. Warfarin must be used cautiously, especially in high-grade gliomas.

Histoplasmosis Outbreaks in Brazil: Lessons to Learn About Preventing Exposure.

Histoplasmosis is considered the most common invasive opportunistic fungal disease in the Americas, with outbreaks and micro-epidemics reported for over 80years. In Brazil, this disease has been described since 1946, reaching a remarkable incidence in the population, especially during the HIV-AIDS pandemic. In this study, published and unpublished outbreaks and micro-epidemics of histoplasmosis in Brazil were revisited by accessing different database sources and evaluating epidemiological and clinical features. We have found reports spanning 1946-2017, across 10 Brazilian states and with involvement of 370 humans and 2 dogs, and 13 disseminated cases and 3 deaths were reported. Rio de Janeiro had the largest number of outbreaks (n = 20/40; 50%) reported in this study. The majority of outbreaks and micro-epidemics was reported in caves (n = 21/40; 52.5%), followed by reports in abandoned/deactivated sites (n = 6/40; 15%), mines (n = 5/40; 12.5%), chicken coops (n = 4/40; 10%). Histoplasmosis is a serious health issue in Brazil considering the attractive and growing market of ecotourism throughout more than 7000 caves, and all levels of poultry farming activity are important to raise awareness about how dangerous this neglected disease can be and establish ways to decrease exposure to contaminated environmental sources through adequate preventive measures.

Neotropical wild rodents Akodon and Oligoryzomys (Cricetidae: Sigmodontinae) as important carriers of pathogenic renal Leptospira in the Atlantic forest, in Brazil

Leptospirosis is an important worldwide zoonosis, caused by a bacterium of the genus Leptospira. For a better understanding of the disease, it is relevant the application of the one health concept. The Atlantic Forest is considered a biodiversity hotspot, with a great endemism of species and despite its importance and proximity to urban areas, the potential role of its fauna as carriers of infectious agents is still poorly understood. Although it is well-known that rats and mice are key reservoirs of leptospires, particularly Rattus norvegicus, wild rodents have also been revealed as reservoirs of leptospiral strains. Thus, the purpose of this study was to investigate the role of the sigmodontine rodents from genera Akodon and Oligoryzomys as pathogenic Leptospira carriers in the Atlantic Forest. We studied 52 Akodon spp. and 15 Oligoryzomys spp. from three areas. Overall 30% were PCR-positive for pathogenic Leptospira, 27% (14/52) Akodon spp. and 40% (6/15) Oligoryzomys spp. DNA sequencing of LipL32 gene confirmed nine species as pathogenic Leptospira. This remarkable incidence of leptospiral carriage within wild genera emphasizes the role of these rodents as carriers of leptospires throughout in this environment.

The Flare Catalog and the Flare Activity in the Kepler Mission

Abstract We present a flare catalog of the Kepler mission using the long-cadence data of Data Release 25. This catalog comprises 3420 flare stars and 162,262 flare events. A comparison shows that the flare catalogs of previous studies are seriously polluted by various false-positive signals and artifacts. The incidence of flare stars rises with decreasing temperature, which accords with the theoretical analysis. The flare frequency distributions (FFDs) from F-type stars to M-type stars obey a power-law relation with α ∼ 2, indicating that they have the same mechanism on generating flares. The remarkable incidence and the deviation of FFDs on A-type flare stars imply that they generate flares in a different way. The activity–rotation relation is consistent with previous studies at low temperature bands, whereas it becomes dispersive with increasing temperature. Combined with the Gyrochronology, we find that the mixing of stars of two different dynamos gives rise to the dispersion. We thereby propose a scenario on understanding the activity–rotation relation across the Hertzsprung-Russell diagram. Based on the scenario and the correspondence of dynamo with regard to activity and rotation, we suggest a new expression on the activity–rotation relation, in which the segmentation is on the basis of the dynamo rather than the rotation period. The rotation distribution of flare stars shows that about 70% of flare stars rotate faster than 10 days and the rate approaches 95% at 30 days. Based on the incidence and the rotation distribution of flare stars, we estimate that a superflare with energy ∼1034 erg occurs on the Sun at least once in 5500 yr.

Creativity-Mood Disorders Link Comes at a Price

Creativity-Mood Disorders Link Comes at a Price

Incircular nets and confocal conics

We consider congruences of straight lines in a plane with the combinatorics of the square grid, with all elementary quadrilaterals possessing an incircle. It is shown that all the vertices of such nets (we call them incircular or IC-nets) lie on confocal conics. Our main new results are on checkerboard IC-nets in the plane. These are congruences of straight lines in the plane with the combinatorics of the square grid, combinatorially colored as a checkerboard, such that all black coordinate quadrilaterals possess inscribed circles. We show how this larger class of IC-nets appears quite naturally in Laguerre geometry of oriented planes and spheres and leads to new remarkable incidence theorems. Most of our results are valid in hyperbolic and spherical geometries as well. We present also generalizations in spaces of higher dimension, called checkerboard IS-nets. The construction of these nets is based on a new 9 9 inspheres incidence theorem.