Historical Events Research Articles

«Слово о законе и благодати»: анализ христологии литературного памятника

This article is a theological analysis of the work "Word on Law and Grace" through the prism of the Christology of the OrthodoX Church. The Old Russian monument was created in the context of St. Hilarion of Kiev’s activity in catechizing believers and conveying the fundamentals of Christian doctrine through poetic and rhetorical forms. The author attaches importance to Christology as a central element in understanding the historical process. St. Hilarion also enters into a polemic with heterodoX views. He emphasizes the divine-human nature of the Savior and the role of oikonomia in the process of human history, which are the key themes in his theological reflections and arguments. In addition, the author builds a coherent argumentation around New Testament subjects, establishing a connection with the prophecies of the Old Testament and the historical event of the Baptism of Rus’. On the one hand, the saint succeeded in creating an original concept of the divine election of the Russian people with an appeal to the text of Holy Scripture, and on the other hand, he succeeded in conveying the foundations of OrthodoX Christology to the believers of the Russian Church.

Earthquake event knowledge graph construction and reasoning

Efficient decision-making in earthquake emergencies plays a crucial role in ensuring individual safety, protecting personal property, and maintaining societal stability. However, traditional approaches to earthquake emergency decision-making rely on manual analysis or rule-based methods, which often struggle to fully leverage the wealth of information and uncover hidden data connections. Consequently, the efficiency of earthquake emergency decision-making is compromised. To address this issue, this study proposes a method for constructing an earthquake event knowledge graph and utilizing it for decision-making in earthquake emergencies. Firstly, specialized earthquake event knowledge ontology is developed, tailored to the unique characteristics of earthquake event data. Secondly, structured instances of earthquake event knowledge are extracted from text using transfer learning techniques, enabling the construction of the earthquake event knowledge graph. Thirdly, the earthquake event knowledge is represented as multidimensional vectors using knowledge graph representation learning technology. This facilitates the identification of similar earthquake events through inference based on vector similarity computation. In conclusion, the results of a case-based study demonstrate the effectiveness of the proposed method in providing accurate outcomes, facilitating earthquake event matching, enabling the retrieval and reuse of historical earthquake event knowledge, and serving as a valuable reference for earthquake emergency decision-making.

Transferability of Empirical Models Derived from Satellite Imagery for Live Fuel Moisture Content Estimation and Fire Risk Prediction

Estimating live fuel moisture content (LFMC) is critical for assessing vegetation flammability and predicting potential fire behaviour, thus providing relevant information for wildfire prevention and management. Previous research has demonstrated that empirical modelling based on spectral data derived from remote sensing is useful for retrieving LFMC. However, these types of models are often very site-specific and generally considered difficult to extrapolate. In the present study, we analysed the performance of empirical models based on Sentinel-2 spectral data for estimating LFMC in fire-prone shrubland dominated by Cistus ladanifer. We used LFMC data collected in the field between June 2021 and September 2022 in 27 plots in the region of Andalusia (southern Spain). The specific objectives of the study included (i) to test previous existing models fitted for the same shrubland species in a different study area in the region of Madrid (central Spain); (ii) to calibrate empirical models with the field data from the region of Andalusia, comparing the model performance with that of existing models; and (iii) to test the capacity of the best empirical models to predict decreases in LFMC to critical threshold values in historical wildfire events. The results showed that the empirical models derived from Sentinel-2 data provided accurate LFMC monitoring, with a mean absolute error (MAE) of 15% in the estimation of LFMC variability throughout the year and with the MAE decreasing to 10% for the critical lower LFMC values (<100%). They also showed that previous models could be easily recalibrated for extrapolation to different geographical areas, yielding similar errors to the specific empirical models fitted in the study area in an independent validation. Finally, the results showed that decreases in LFMC in historical wildfire events were accurately predicted by the empirical models, with LFMC <80% in this fire-prone shrubland species.

Sudden cardiac death after early-onset myocardial infarction. A multicentre longitudinal cohort study with 20 years' follow-up.

Sudden cardiac death (SCD) is a serious consequence of a myocardial infarction (MI), but identifying patients at risk of developing SCD remains a major clinical challenge especially in the case of juvenile MI. The aim of this study was to identify predictors of SCD after early-onset MI using long-term follow-up data relating to a large nationwide patient cohort. The Italian Genetic Study on Early-onset MI enrolled 2,000 patients experiencing a first MI before the age of 45 years, who were followed up for a median of 19.9 years. Fine-Gray proportional hazard models were used to assess the associations between their clinical, demographic and index event data and the occurrence of SCD. SCD occurred in 195 patients, who were more frequently males, hypertensive and/or diabetic; had a history of previous thromboembolic events with a greater atherosclerotic burden; and had a lower left ventricular ejection fraction (LVEF) after the index event. Multivariable analysis showed that the independent predictors of SCD were diabetes, hypertension, previous thromboembolic events, higher Syntax score, and a lower LVEF. There was no clear evidence of the clustering of SCD events during follow-up. SCD was the first post-MI clinical event in 101 patients; the remaining 94 experienced SCD after a non-fatal MI or hospitalisation for coronary revascularisation. SCD frequently occurs during the 20 years after early-onset MI. The nature of the identified predictors and the absence of clustering suggests that the pathophysiological basis of SCD may be related to progressive coronary atherosclerosis.

Multi-perspective feedback-attention coupling model for continuous-time dynamic graphs

Abstract Representation learning over graph networks has recently gained popularity, with many models showing promising results. However, several challenges remain: (1) most methods are designed for static or discrete-time dynamic graphs; (2) existing continuous-time dynamic graph algorithms focus on a single evolving perspective; and (3) many continuous-time dynamic graph approaches necessitate numerous temporal neighbors to capture long-term dependencies. In response, this paper introduces a Multi-Perspective Feedback-Attention Coupling (MPFA) model. MPFA incorporates information from both evolving and original perspectives to effectively learn the complex dynamics of dynamic graph evolution processes. The evolving perspective considers the current state of historical interaction events of nodes and uses a temporal attention module to aggregate current state information. This perspective also makes it possible to capture long-term dependencies of nodes using a small number of temporal neighbors. Meanwhile, the original perspective utilizes a feedback attention module with growth characteristic coefficients to aggregate the original state information of node interactions. Experimental results on one dataset organized by ourselves and seven public datasets validate the effectiveness and competitiveness of our proposed model.

Homogeneous earthworm communities in Southern Ontario

Earthworms are key organisms of soil ecosystems, however, the determinants of the structure and distribution of earthworm communities and their relationships with agricultural practices are not well-studied in Canada. We sampled earthworm communities from four different habitat types along a disturbance gradient: agricultural crop land, forest around crop fields (buffers), recently restored natural grassland, and forests from conservation areas. As most species living in Canada are considered exotic and because of the recent colonization of Canadian soils by mostly European species after the extinction of the native species due to the glaciation of North America during the Pleistocene, we hypothesized that the impact of agricultural practices will be similar to what is observed in Europe: for example, crop habitat showing lowest abundance, richness, and proportion of epigeic and anecic species, due to lesser soil organic matter content and higher soil disturbance. We also hypothesized that important soil variables would be associated with these habitat differences. For each habitat we sampled earthworms using a combination of two methods (quantitative + qualitative) at three replicate sites, for two years between May and July together with important environmental variables. We found lower density and diversity of earthworms in crop habitat and proportionally more epigeic species than expected. Contrary to our predictions, forest-buffer earthworm communities were more similar to crop than to forest habitats, and soil environmental variables could not explain the variations in the spatial distribution of earthworm communities. In fact, our results revealed a more homogeneous distribution of the species diversity across the habitat gradient at local scales in Southern Ontario. This was mainly associated with spatial factors, probably due to historical extinction-colonization events of earthworms in Canada and the high invasive potential of the species currently present.

The year of jubilees

The years 2023–2024 bring up some significant anniversaries for a range of historical events in the development of modern intellectual property law. Many of them have implications for how patents are obtained and recorded in the public domain. The original documents are cited for further reading.

Hospital-based skilled nursing facility survival: Organizational and market-level predictors.

Rising health care costs and consequent increases in Medicare reimbursements have led to many payment reforms over the years. Implementation of the prospective payment system (PPS) for hospitals in 1983 incentivized hospitals to either purchase skilled nursing facilities (SNFs) or utilize their excess capacity to establish one within the hospital. With PPS reimbursement being applied to SNFs in 1998, prior monetary incentives for hospitals to own an SNF disappeared. However, despite the reduction in numbers, many hospitals continued to operate their hospital-based skilled nursing facilities (HBSNFs). This study examines the organizational and market-level factors associated with the survival of HBSNFs using the population ecology of organizations framework. Using American Hospital Association survey data, event histories of all U.S. acute care hospitals with an open HBSNF in 1998 were plotted to examine if a hospital closed its HBSNF during a 22-year period (1998-2020). The primary independent variables included hospital size, ownership, total margin, market competition, and Medicare Advantage penetration. The independent and control variables were lagged by 1 year. Cox regressions were conducted to estimate the hazard ratios capturing the risk of HBSNF closure. The results showed that HBSNFs located in large, not-for-profit hospitals and those operating in less competitive markets had greater odds of surviving. The HBSNF administrators of small, for-profit hospitals and those operating in highly competitive markets could utilize the findings of this study to judiciously allocate slack resources to their HBSNFs to keep those open given the current emphasis on continuity of care by regulatory bodies.

Artificial intelligence in healthcare and medicine: the history of key events, its significance for doctors, the level of development in different countries

The article is devoted to analysis of the stages of development and current directions of research and practical application of artificial intelligence (AI) in the field of healthcare and medicine based on scientific publications in PubMed/MEDLINE, Scopus, Web of Science, Embase, eLibrary and CyberLeninka. The dynamics of scientific publications on AI in healthcare and medicine is shown, and an analysis of the growth of investments in software development based on AI in recent years is provided. AI can achieve comparable accuracy in the diagnosis of diseases in comparison with human decisions. However, future research should focus on comparing the clinical results of diagnosis and treatment performed by doctors who make decisions based on AI with the results of clinical work by doctors who do not use AI. The importance of training specialists able to combine knowledge in the field of medicine with the skills of using AI is emphasized.

Statewide Community College Promise Programs: An Event History Analysis

ABSTRACT Between the 2014 adoption of the Tennessee Promise Act and 2019, 16 states enacted their own statewide promise program policies making community college tuition free for numerous students. In this study, we sought to determine which state-level factors predicted the adoption of a statewide promise program policy. Using data from 2013 to 2019, we conducted an event history analysis to identify state-level political, economic, social, and higher education system conditions that predicted promise program policy adoption. Partisan control of state government, total state population, percentage of state population identified as white, and percentage of state appropriations allocated to community colleges were associated with statewide promise program policy adoption. Our findings suggest that there is no single factor or grand narrative that results in promise program policy adoption. Instead, the results highlight the complexities within the policymaking process.

Parsimonious streamflow forecasting system based on a dynamical systems approach

Operational hydrologic forecasting often relies on the use of physically-based computer models at the catchment scale. However, our understanding of streamflow generation is still evolving and incomplete, and oftentimes linearization assumptions must be made to make physically-based hydrologic and hydraulic models tractable. In addition to uncertainty in the physical runoff-generation mechanisms, many physically-based approaches do not formally assimilate observed streamflow data. Streamflow is their output, deterministically simulated from observed inputs (such as precipitation, temperature, etc.). Divergences between observed and simulated streamflow may be due to input uncertainty, calibration issues, or problems with the inherent physical process representation. Thus, data-driven approaches that are responsive to observed streamflow by including assimilation as an essential feature are promising in operational hydrology. In this study, we use a novel forcings-weighted k-Nearest Neighbor (kNN) nonlinear timeseries forecasting method developed in the context of the modeling of nonlinear dynamical systems. The rainfall-runoff transform is assumed to be a low-dimensional system of (unknown) nonlinear differential equations; the deterministic state space is reconstructed based on the streamflow timeseries; and a forecast is generated based on how “similar” the current hydrograph is to historical events encoded within the reconstructed state space, weighted by the similarity of forcings. We tested the model in a long-term test period with no real data assimilation, and in forecast mode with daily data assimilation. When used for forecasting, we also illustrate two different uncertainty quantification approaches: forecast postprocessing and internal-to-the-model ensemble generation. The method is conceptually and computationally simple, but offers promising results. We tested the model in three different scenarios. First, investigating a long-term test period with no real data assimilation in a rainfall-dominated research catchment at the Coweeta Hydrologic Lab in North Carolina, USA. The simulation exhibited an NSE of 0.73. Next, we included a conceptual snowmelt model to drive the long term simulation and studied boreal-temperate transition zone catchments in northern Minnesota, USA. The study area included a small (<0.1 mi2) reference research catchment at the Marcell Experimental Forest, and a large river basin (>19 k mi2) with incomplete forcings information. The kNN method yielded NSEs from 0.28 to 0.50. And finally, we conducted a pseudo-operational forecasting test for a large river basin in northern Minnesota, USA with a focus on performance forecasting a flood-of-record on the Rainy River. The test involved reforecasting, data assimilation, and implementation of ensemble and postprocessing bias correction uncertainty-quantification schemes. The technique demonstrated good performance capturing a flood-of-record on a large catchment (−5.7 to −3.3 % crest error with 1-day of lead time). For the entire test period in forecast mode, the 1-day lead time NSE was 0.99, going down to 0.79 for the 7-day lead time, showing its general utility as an operational forecasting tool.

Addressing neurosurgical challenges in war conflict countries.

The Russo-Ukrainian war caused significant humanitarian and healthcare issues in the Russo-Ukrainian region, which were further aggravated by the escalation of the conflict on February 2022. Because of this ongoing confrontation between the two nations, which has its roots in geopolitical conflicts and historical events, there have been nearly 4million refugees in only the first month, and 906 healthcare institutions have sustained significant damage. Consequently, the demand for medical services has increased, adding onto the burden of the pre-existing problems within the region's healthcare system, such as inequities, budget shortages, and corruption. With nearly 500,000 military deaths and an estimated 27,1499 civilian casualties, the war's immediate health effects are devastating. Due to inadequate disease surveillance and difficulties with immunization, the risk of infectious illnesses, particularly HIV/AIDS and tuberculosis, increased. Although there were originally few mental health problems, the long-term effects are yet unknown. Some of the indirect effects are the severe refugee situation, the burden on public infrastructure, and problems with the security of food and water. Unprecedented obstacles confronted neurosurgery in the Russo-Ukrainian region, including increased patient loads from war-related cases, resource limitations, and facility devastation. Many countries stepped up to aid in managing neurosurgeries however, the some of the problems still persisted, such as insufficient sterility and power outages. Strengthened security standards, financial incentives, telemedicine services, and cooperation with international medical organizations are the main points of recovery recommendations. Rebuilding the region's healthcare system and guaranteeing ongoing foreign support after the conflict require a comprehensive strategy that addresses both short- and long-term issues.

Characteristics of T cell premature senescence in maintenance hemodialysis patients.

Uremia-associated immunodeficiency, mainly characterized by T cell dysfunction, exists in patients on maintenance hemodialysis (MHD) and promotes systemic inflammation. However, T cell senescence, one of the causes of T cell dysfunction, has not been clearly revealed yet. In this cross-sectional research, we aimed to study the manifestation of T cell premature senescence in MHD patients and further investigate the associated clinical factors. 76 MHD patients including 33 patients with cardiovascular diseases (CVD) and 28 patients with arteriovenous fistula (AVF) event history were enrolled in this study. Complementarity determining region 3 (CDR3) of T cell receptor (TCR) was analyzed by immune repertoire sequencing (IR-Seq). CD28- T cell subsets and expression of senescence marker p16 and p21 genes were detected by multicolor flow cytometry and RT-qPCR, respectively. MHD patients had significantly decreased TCR diversity (P < 0.001), increased CDR3 clone proliferation (P = 0.001) and a left-skewed CDR3 length distribution. The proportion of CD4 + CD28- T cells increased in MHD patients (P = 0.014) and showed a negative correlation with TCR diversity (P = 0.001). p16 but not p21 expression in T cells was up-regulated in MHD patients (P = 0.039). Patients with CVD exhibited increased expression of p16 and p21 genes (P = 0.010 and 0.004, respectively), and patients with AVF events showed further TCR diversity and evenness reduction (P = 0.002 and 0.017, respectively) compared to patients without the comorbidities. Moreover, age, average convection volume, total cholesterol, high-density lipoprotein cholesterol and transferrin saturation were associated with TCR diversity or CD4 + CD28- T cell proportion (P < 0.05). MHD patients undergo T cell premature senescence characterized by significant TCR diversity reduction and repertoire skew, as well as accumulation of the CD4 + CD28- subset and up-regulation of p16 gene. Patients with CVD or AVF events show higher level of immunosenescence. Furthermore, T cell senescence in MHD patients is associated with blood cholesterol and uremic toxin retention, suggesting potential intervention strategies in the future.

Observations of Igneous Subsurface Stratigraphy during the Jezero Crater Floor Rapid Traverse from the RIMFAX Ground-penetrating Radar

Perseverance traversed the eastern, northern, and western margins of the Séítah formation inlier on the rover’s western fan front approach. Mapping the stratigraphy and extent of the Máaz and Séítah formations is key to understanding the depositional history and timing of crater floor resurfacing events. Perseverance's rapid progress across the Jezero crater floor between the Octavia E. Butler landing site and the western fan front resulted in limited contextual images of the deposits from the Navigation Camera and Mast Camera Zoom. By combining the limited surface images with continuous subsurface sounding by the Radar Imager for Mars’ Subsurface Experiment (RIMFAX) ground-penetrating radar, Jezero crater floor stratigraphy was inferred along this rapid traverse. We produced the first subsurface map of the Máaz formation thickness and elevation of the buried Séítah formation for 2.3 km of the rapid traverse. Three distinct reflector packets were observed in RIMFAX profiles interspersed with regions of low-radar reflectivity. We interpret these reflector packets with increasing depth to be the Roubion member of the Máaz formation (covered in places with regolith), the Rochette member, and the Séítah formation. We found a median permittivity of 9.0 and bulk density of 3.2 g cm−3 from hyperbola fits to RIMFAX profiles, which suggests a mafic composition for Máaz and Séítah. The low-radar reflectivity regions within each reflector packet could indicate potential depositional hiatuses where low-density material like sediment or regolith could have accumulated between successive Máaz formation lava flows and the Séítah formation at depth.

Cardiac stasis imaging, stroke, and silent brain infarcts in patients with nonischemic dilated cardiomyopathy.

Cardioembolic stroke is one of the most devastating complications of nonischemic dilated cardiomyopathy (NIDCM). However, in clinical trials of primary prevention, the benefits of anticoagulation are hampered by the risk of bleeding. Indices of cardiac blood stasis may account for the risk of stroke and be useful to individualize primary prevention treatments. We performed a cross-sectional study in patients with NIDCM and no history of atrial fibrillation (AF) from two sources: 1) a prospective enrollment of unselected patients with left ventricular (LV) ejection fraction <45% and 2) a retrospective identification of patients with a history of previous cardioembolic neurological event. The primary end point integrated a history of ischemic stroke or the presence intraventricular thrombus, or a silent brain infarction (SBI) by imaging. From echocardiography, we calculated blood flow inside the LV, its residence time (TR) maps, and its derived stasis indices. Of the 89 recruited patients, 18 showed a positive end point, 9 had a history of stroke or transient ischemic attack (TIA) and 9 were diagnosed with SBIs in the brain imaging. Averaged TR, [Formula: see text] performed well to identify the primary end point [AUC (95% CI) = 0.75 (0.61-0.89), P = 0.001]. When accounting only for identifying a history of stroke or TIA, AUC for [Formula: see text] was 0.92 (0.85-1.00) with odds ratio = 7.2 (2.3-22.3) per cycle, P < 0.001. These results suggest that in patients with NIDCM in sinus rhythm, stasis imaging derived from echocardiography may account for the burden of stroke.NEW & NOTEWORTHY Patients with nonischemic dilated cardiomyopathy (NIDCM) are at higher risk of stroke than their age-matched population. However, the risk of bleeding neutralizes the benefit of preventive oral anticoagulation. In this work, we show that in patients in sinus rhythm, the burden of stroke is related to intraventricular stasis metrics derived from echocardiography. Therefore, stasis metrics may be useful to personalize primary prevention anticoagulation in these patients.

Frequency of clinico-hematological features and JAK 2 status of young adults presenting with polycythemia in RMI hospital, Peshawar.

Objective: To determine the frequency of clinico-hematological features and JAK 2 status of young adults presenting with Polycythemia Vera at the department of hematology. Study Design: Cross-sectional study. Setting: Department of Hematology, RMI Hospital, Peshawar. Period: 25th November 2023 to 25th May 2024. Methods: A total of 190 patients aging between 18-45 years and presented as suffering from Polycythemia Vera as per diagnosis of consultant hematopathologists, were included in this study. Samples with clear evidence of hemolysis, coagulation, or clots were excluded. Patient’s demographics, details of physical appearance, clinical findings and history of adverse events were recorded. Hematological and pathological investigations were done and analysis of JAK2 V617F mutation was conducted using polymerase chain reaction from the diagnostic lab of the institute. The primary outcome of the study was to determine the frequency of clinico-hematological features and JAK 2 status. Results: The Mean±SD of age in our study was 36.81±6.11 years with an age range of 21-45 years. Out of total patients, 49 (25.79%) patients were asymptomatic. The major symptoms affecting the daily life activities were headache 65 (34.21), abdominal discomfort 41 (21.58%), blurred vision 27 (14.21%) and fatigue 27 (14.21%). These patients had plethoric face 61 (32.11%), splenomegaly 64 (33.68%) and budd-chiari syndrome 8 (4.21%). The results of hematopathological findings showed abnormal hemoglobin (17±3.92 gm/dL), hematocrit (52.94±4.8 g %), platelet (579.63±227.68 103/μL) and leukocyte (10.32±2.6, 103/μL) levels while 177 (93.16 %) patients had mutated JAK2 levels. Conclusion: Plethoric face and splenomegaly are the commonly found clinical findings in patients with Polycythemia Vera while these patients also have abnormal levels of hemoglobin, hematocrit, platelet and leukocyte. JAK 2 status serves conclusive role in the diagnosis of Polycythemia Vera.

Elderly patients with very high plasma lipoprotein(a) concentrations and few cardiovascular consequences: a case series.

Lipoprotein(a) (Lp(a)) is an atherogenic low-density lipoprotein (LDL)-like particle that is currently regarded as a non-modifiable risk factor for atherosclerotic cardiovascular disease. The number of patients detected with elevated Lp(a) concentrations has been increasing in recent years, although the implication of this finding is unclear for patients and physicians. We screened our lipid clinic database for patients aged >65 years with very high Lp(a) concentrations, which were defined as >230 nmol/L, and cardiovascular outcomes were assessed. The patients' (n = 16) mean (±standard deviation) age was 72.2 ± 7.1 years and the mean Lp(a) concentration was 313 ± 68 nmol/L. After a cumulative 129.0 patient-year follow-up (mean: 8.1 ± 4.2 years), the mean age was 80.3 ± 7.0 years. We observed a low baseline prevalence of cardiovascular events, with only two patients having a history of cardiovascular events. Furthermore, zero incident adverse cardiovascular events were recorded over the follow-up. Therefore, very high Lp(a) concentrations and disease-free old age are not mutually exclusive. Our aggregated clinical experience is that there is only a modest association between elevated Lp(a) concentrations and adverse outcomes. Nonetheless, we still advise treating modifiable risk factors in these patients.

Fundamentals of Nonsuicidal Self-Injury in Pediatric Patients.

Nonsuicidal self-injury (NSSI) is deliberate self-inflicted injury to one's own body without suicidal intent. There is a high prevalence of NSSI among adolescents, especially in adolescents with history of adverse childhood events and intense reactive emotions. Pediatricians are commonly the first point of contact for adolescents and preadolescents with mental health concerns, and knowledge of how to elicit and respond to reports of NSSI are critical in identifying, supporting, and making appropriate referrals to behavioral health providers. Appropriate referrals include a psychiatric assessment by a child and adolescent psychiatrist and licensed therapist. Therapy targets NSSI by identifying the function of the behavior for the patient and finding ways to obtain that function safely using coping skills. Pediatricians should consider their role in setting the tone for families to engage in productive mental health treatment, with the goal of having the adolescent and caregiver work collaboratively to use healthy coping skills. [Pediatr Ann. 2024;53(8):e280-e282.].

Proper Motions and Orbits of Distant Local Group Dwarf Galaxies from a Combination of Gaia and Hubble Data

We have determined the proper motions (PMs) of 12 dwarf galaxies in the Local Group (LG), ranging from the outer Milky Way (MW) halo to the edge of the LG. We used the Hubble Space Telescope (HST) as the first and Gaia as the second epoch using the GaiaHub software. For Leo A and Sag DIG, we also used multi-epoch HST measurements relative to background galaxies. Orbital histories derived using these PMs show that two-thirds of the galaxies in our sample are on first infall with >90% certainty. The observed star formation histories of these first-infall dwarfs are generally consistent with infalling dwarfs in simulations. The remaining four galaxies have crossed the virial radius of either the MW or M31. When we compare their star formation (SF) and orbital histories we find tentative agreement between the inferred pattern of SF with the timing of dynamical events in the orbital histories. For Leo I, SF activity rises as the dwarf crosses the MW’s virial radius, culminating in a burst of SF shortly before pericenter (≈1.7 Gyr ago). The SF then declines after pericenter, but with some smaller bursts before its recent quenching (≈0.3 Gyr ago). This shows that even small dwarfs like Leo I can hold onto gas reservoirs and avoid quenching for several gigayears after falling into their host, which is longer than generally found in simulations. Leo II, NGC 6822, and IC 10 are also qualitatively consistent with this SF pattern in relation to their orbit, but more tentatively due to larger uncertainties.

Historic Flood Events and Current Flood Hazard in Ulaanbaatar City, Central Mongolia

Climate change will increase the frequency of extreme weather events, alter rainfall patterns, and exacerbate flood disasters in Ulaanbaatar City. Here we combine aerial and satellite imagery with cadastral data, to scrutinize the historical trajectory of rainfall patterns and flood disasters in Ulaanbaatar over the past six decades. The study focusses on the causative factors behind historical floods, current flood conditions, the geographical distribution of floods, land ownership in floodprone areas, and the spatial allocation of fences and buildings based on social conditions. Over the last 60 years, Ulaanbaatar received a total of 16,780 mm of precipitation, with a staggering 80.5% of this total occurring during the summer season. Over this period, the city has endured about ten significant flood disasters. The most severe and destructive events occurred in 1966, 1982, 1994, 2003, 2009, and 2023 as river basins and mountain flash floods. These flood events claimed at least 220 lives, affected around 46,000 households, and caused economic losses of ca. 3.3 million U.S. dollars. Our study identifies several flood hazard areas along the Tolgoit, Selbe, Uliastai, and Tuul River valleys, which define a flood buffer zone extending 200 m from their banks, encompassing 59 khoroos of 7 districts in Ulaanbaatar. There are 27,970 fences and 12,887 buildings in the 200 m buffer zone, which is 66.5% of all fence unit area, and 46.3% of the total building, situated within the identified flood risk areas. In response to these findings, we emphasize the urgent need for comprehensive long-term strategy for sustainable flood management based on disaster resilence.