Updated statistics for crater clusters on Mars

An increasing number of newly formed impact craters on Mars have been detected in the last 15 years. These small craters are normally identified via dark spots in lower resolution images that formed during the impact process, presumably through the removal or disturbance of bright surface material [1]. Later higher resolution images revealed single craters or crater clusters, which form when impactors fragment in the atmosphere, within those halos [1,2]. Due to this detection method, most of the new impact sites found are in dusty regions, which imposes an observational bias [3]. Newly formed clusters consist of two to thousands of individual craters and can be tightly clustered or spread out over hundreds of meters [2]. Since the InSight (Interior Exploration using Seismic Investigations, Geodesy and Heat Transport) mission landed on Mars in 2018 [4], the search for newly formed impact craters has become even more important, because identifying impacts in seismic signals could provide further constraints on both the atmospheric and solid-body effects of impact cratering process on Mars, as well as help place further constraints on the properties of the uppermost layer of the crust. As one of InSight&#8217;s mission goals is to estimate the current impact rate on Mars, the seismic detection of impacts is also crucial [4]. The aim of this new study is to describe the properties of the complete catalog of known newly formed craters on Mars and examine correlations between different crater cluster properties. We investigated 559 crater clusters and 493 single craters detected between 2008 and 2020 using 25 cm/px HiRISE images. The locations and diameters were noted for each single crater, as well as for every individual crater within a cluster down to 1 m diameter. This was done using ArcMap (ArcGIS) software with the three-point method of the CraterTools add-in [5]. We describe the cluster characteristics, such as the number of craters within a cluster, largest crater in a cluster, cluster effective diameter, cluster dispersion, elevation of the impact sites, and the variation in sizes of craters within a cluster. More than half of the new impact sites form as clusters. We did not find any differences between the spatial distribution of single and crater clusters across Mars. The mapped crater clusters from this study consist of 2 to 2334 individual craters. More than half of all clusters (58%) consist of 10 craters or less. Crater clusters containing more than 100 craters are rare. With regard to the sizes of craters within crater clusters, we found that for highly populated clusters, the majority of craters are very small, and clusters with few craters have a tendency for craters that are more equal in size. Clusters having large effective diameters contain more equally sized craters. Our results show the full range of parameter spaces that are possible for cluster properties, which can help validate theoretical atmospheric fragmentation models. References: [1] Malin M. C. et al. (2006) Science, 314, 1573-1577. [2] Daubar I. J. et al. (2019) JGR, 124, 958-969. [3] Daubar I. J. et al. (2013) Icarus, 225, 506-516. [4] Banerdt B. W. et al. (2020) Nature, 13, 183-189. [5] Kneissl T. et al. (2011) Planet. Space Sci., 59, 1243-1254.

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Transitional impact craters on the Moon: Insight into the effect of target lithology on the impact cratering process

Meteoritics and Planetary Science ◽

10.1111/maps.13226 ◽

2018 ◽

Cited By ~ 4

Author(s):

Gordon R. Osinski ◽

Elizabeth A. Silber ◽

Jacqueline Clayton ◽

Richard A. F. Grieve ◽

Kayle Hansen ◽

...

Keyword(s):

Impact Craters ◽

The Moon ◽

Impact Cratering ◽

The Impact ◽

Insight Into

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Unfunded Public Employee Health Care Benefits and GASB No. 45

Accounting Horizons ◽

10.2308/acch.2007.21.3.245 ◽

2007 ◽

Vol 21 (3) ◽

pp. 245-263 ◽

Cited By ~ 10

Author(s):

Elizabeth K. Keating ◽

Eric S. Berman

Keyword(s):

Health Care ◽

Financial Reporting ◽

Full Range ◽

Financial Reports ◽

Employment Benefits ◽

Care Plans ◽

Advantages And Disadvantages ◽

Government Accounting ◽

The Government ◽

The Impact

The Government Accounting Standards Board (GASB) recently released Statement No. 45, Accounting and Financial Reporting by Employers for Post-Employment Benefits Other Than Pensions and its companion Statement No. 43 for pooled stand-alone health care plans, which will profoundly affect American governmental finance. The goal of this article is to encourage governments to consider carefully a full range of options in funding and restructuring other post-employment benefits (OPEB). This article will review Statement No. 45's potential impact on governments and review existing disclosures in financial reports as well as bond offering statements. The article will discuss the statement's impact on budgets and governmental operations, including collective bargaining. Funding options under Statement No. 45 will be detailed, including the advantages and disadvantages of irrevocable trusts and OPEB bonds. The article will also discuss the impact of Medicare Part D subsidies received by governments, as well as the bond rating implications of policy decisions surrounding OPEB. As the largest government entities are just now implementing GASB Statement No. 45, estimates of the magnitude of unfunded OPEB liabilities are limited as are the strategies likely to be adopted to cover these obligations. This article offers a summary of the unfunded OPEB liabilities reported by states and major cities and suggests some measures for assessing the ability of these entities to address these costs.

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Self-Secondaries Formed by Cold Spot Craters on the Moon

Remote Sensing ◽

10.3390/rs13061087 ◽

2021 ◽

Vol 13 (6) ◽

pp. 1087

Author(s):

Yiren Chang ◽

Zhiyong Xiao ◽

Yang Liu ◽

Jun Cui

Keyword(s):

Systematic Investigation ◽

Impact Craters ◽

Spatial Density ◽

Cold Spot ◽

The Moon ◽

Potential Threat ◽

Frequency Distributions ◽

Crater Size ◽

The Impact ◽

Density Pattern

Self-secondaries are a population of background secondaries, and they have been observed on top of impact melt and ballistically emplaced ejecta deposits on various planetary bodies. Self-secondaries are formed by impacts of sub-vertically launched ejecta, but the launch mechanism is not confirmed. The potential threat of self-secondaries to the theoretical and applicable reliability of crater chronology has been noted, but not constrained. Hitherto discovered self-secondaries were located around complex impact craters, but their potential existence around simple craters has not been discovered. Here we report the first discovery of self-secondaries around lunar cold spot craters, which are an extremely young population of simple craters formed within the past ~1 million years on the Moon. Self-secondaries are widespread on layers of cascading flow-like ejecta deposits around cold spot craters. The spatial density of self-secondaries dwarfs that of potential primary craters. The spatial distribution of self-secondaries is highly heterogeneous across the ejecta deposits. With respect to the impactor trajectory that formed cold spot craters, self-secondaries formed at the downrange of the ejecta deposits have the largest spatial density, while those at the uprange have the smallest density. This density pattern holds for all cold spot craters that were formed by non-vertical impacts, but self-secondaries do not exhibit other systematic density variations at different radial distances or at other azimuths with respect to the impactor trajectory. Among known mechanics of ejecting materials to the exterior of impact craters, impact spallation is the most likely scenario to account for the required large ejection velocities and angles to form self-secondaries. The production population of self-secondaries is estimated based on the highly diverse crater size-frequency distributions across the ejecta deposits of cold spot craters. For a better understanding of the impact history on the Moon, a systematic investigation for the effect of self-secondaries on lunar crater chronology is required.

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High-Resolution Climate Change Impact Analysis on Expected Future Water Availability in the Upper Jordan Catchment and the Middle East

Journal of Hydrometeorology ◽

10.1175/jhm-d-13-0153.1 ◽

2014 ◽

Vol 15 (4) ◽

pp. 1517-1531 ◽

Cited By ~ 15

Author(s):

Gerhard Smiatek ◽

Harald Kunstmann ◽

Andreas Heckl

Keyword(s):

Climate Change ◽

High Resolution ◽

Water Availability ◽

Impact Analysis ◽

River Flow ◽

Climate Model ◽

Mesoscale Model ◽

Global Climate Model ◽

Full Range ◽

The Impact

Abstract The impact of climate change on the future water availability of the upper Jordan River (UJR) and its tributaries Dan, Snir, and Hermon located in the eastern Mediterranean is evaluated by a highly resolved distributed approach with the fifth-generation Pennsylvania State University–NCAR Mesoscale Model (MM5) run at 18.6- and 6.2-km resolution offline coupled with the Water Flow and Balance Simulation Model (WaSiM). The MM5 was driven with NCEP reanalysis for 1971–2000 and with Hadley Centre Coupled Model, version 3 (HadCM3), GCM forcings for 1971–2099. Because only one regional–global climate model combination was applied, the results may not give the full range of possible future projections. To describe the Dan spring behavior, the hydrological model was extended by a bypass approach to allow the fast discharge components of the Snir to enter the Dan catchment. Simulation results for the period 1976–2000 reveal that the coupled system was able to reproduce the observed discharge rates in the partially karstic complex terrain to a reasonable extent with the high-resolution 6.2-km meteorological input only. The performed future climate simulations show steadily rising temperatures with 2.2 K above the 1976–2000 mean for the period 2031–60 and 3.5 K for the period 2070–99. Precipitation trends are insignificant until the middle of the century, although a decrease of approximately 12% is simulated. For the end of the century, a reduction in rainfall ranging between 10% and 35% can be expected. Discharge in the UJR is simulated to decrease by 12% until 2060 and by 26% until 2099, both related to the 1976–2000 mean. The discharge decrease is associated with a lower number of high river flow years.

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Compressor Performance and Operability in Swirl Distortion

Volume 7: Turbomachinery, Parts A, B, and C ◽

10.1115/gt2010-22777 ◽

2010 ◽

Cited By ~ 1

Author(s):

Yogi Sheoran ◽

Bruce Bouldin ◽

P. Murali Krishnan

Keyword(s):

Gas Turbine ◽

Complex Geometry ◽

Full Range ◽

Axial Compressor ◽

Cfd Model ◽

Generator System ◽

Sliding Mesh ◽

Wide Range ◽

Compressor Performance ◽

The Impact

Inlet swirl distortion has become a major area of concern in the gas turbine engine community. Gas turbine engines are increasingly installed with more complicated and tortuous inlet systems, like those found on embedded installations on Unmanned Aerial Vehicles (UAVs). These inlet systems can produce complex swirl patterns in addition to total pressure distortion. The effect of swirl distortion on engine or compressor performance and operability must be evaluated. The gas turbine community is developing methodologies to measure and characterize swirl distortion. There is a strong need to develop a database containing the impact of a range of swirl distortion patterns on a compressor performance and operability. A recent paper presented by the authors described a versatile swirl distortion generator system that produced a wide range of swirl distortion patterns of a prescribed strength, including bulk swirl, twin swirl and offset swirl. The design of these swirl generators greatly improved the understanding of the formation of swirl. The next step of this process is to understand the effect of swirl on compressor performance. A previously published paper by the authors used parallel compressor analysis to map out different speed lines that resulted from different types of swirl distortion. For the study described in this paper, a computational fluid dynamics (CFD) model is used to couple upstream swirl generator geometry to a single stage of an axial compressor in order to generate a family of compressor speed lines. The complex geometry of the analyzed swirl generators requires that the full 360° compressor be included in the CFD model. A full compressor can be modeled several ways in a CFD analysis, including sliding mesh and frozen rotor techniques. For a single operating condition, a study was conducted using both of these techniques to determine the best method given the large size of the CFD model and the number of data points that needed to be run to generate speed lines. This study compared the CFD results for the undistorted compressor at 100% speed to comparable test data. Results of this study indicated that the frozen rotor approach provided just as accurate results as the sliding mesh but with a greatly reduced cycle time. Once the CFD approach was calibrated, the same techniques were used to determine compressor performance and operability when a full range of swirl distortion patterns were generated by upstream swirl generators. The compressor speed line shift due to co-rotating and counter-rotating bulk swirl resulted in a predictable performance and operability shift. Of particular importance is the compressor performance and operability resulting from an exposure to a set of paired swirl distortions. The CFD generated speed lines follow similar trends to those produced by parallel compressor analysis.

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Damping Studies on PMLG-Based Wave Energy Converter under Oceanic Wave Climates

Energies ◽

10.3390/en14040920 ◽

2021 ◽

Vol 14 (4) ◽

pp. 920

Author(s):

Yue Hong ◽

Irina Temiz ◽

Jianfei Pan ◽

Mikael Eriksson ◽

Cecilia Boström

Keyword(s):

Wave Energy ◽

Energy Production ◽

Full Range ◽

Electrical Power ◽

Damping Coefficient ◽

Irregular Wave ◽

Ocean Wave Energy ◽

Optimal Damping ◽

The Impact

Wave energy converters (WECs), which are designed to harvest ocean wave energy, have recently been improved by the installation of numerous conversion mechanisms; however, it is still difficult to find an appropriate method that can compromise between strong environmental impact and robust performance by transforming irregular wave energy into stable electrical power. To solve this problem, an investigation into the impact of varied wave conditions on the dynamics of WECs and to determine an optimal factor for WECs to comply with long-term impacts was performed. In this work, we researched the performance of WECs influenced by wave climates. We used a permanent magnet linear generator (PMLG)-based WEC that was invented at Uppsala University. The damping effect was first studied with a PMLG-type WEC. Then, a group of sea states was selected to investigate their impact on the power production of the WEC. Two research sites were chosen to investigate the WEC’s annual energy production as well as a study on the optimal damping coefficient impact. In addition, we compared the WEC’s energy production between optimal damping and constant damping under a full range of sea states at both sites. Our results show that there is an optimal damping coefficient that can achieve the WEC’s maximum power output. For the chosen research sites, only a few optimal damping coefficients were able to contribute over 90% of the WEC’s annual energy production. In light of the comparison between optimal and constant damping, we conclude that, for specific regions, constant damping might be a better choice for WECs to optimize long-term energy production.

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EMERGENCY SURGERY DURING COVID 19 AT K.A.P.V GOVERNMENT MEDICAL COLLEGE AND MGMGH , TRICHY

10.36106/ijar/8200303 ◽

2021 ◽

pp. 6-9

Author(s):

Sumathi Ravikumar ◽

Yeganathan Rajappan ◽

Durairajan Vaithiyanathan ◽

Catherine Sindhuja

Keyword(s):

Surgical Intervention ◽

District General Hospital ◽

Favourable Outcome ◽

Emergency General Surgery ◽

Emergency Admissions ◽

Medical College ◽

Prolonged Duration ◽

Current Impact ◽

Emergency Surgical Intervention ◽

The Impact

COVID 19 pandemic was declared by WHO as public health emergency on January 30,2020. Health system was reorganised with the aim to cope with the new disease and maintain essential health service. Many patients suffered from ARDS which lead to the modication of clinical and surgical activity. Current impact of COVID 19 outbreak on emergency surgical practice is still not developed. Varied presentation, diagnostic uncertainity, lack of guidelines present challenges to surgeons. AIM: The aim of our study was to evaluate the impact of the COVID-19 pandemic on emergency general surgery admissions and operations in our institution METHODS: We conducted a retrospective study in K.A.P.V.G.M.C. and M.G.M.G.H., Trichy from march 2020 to December 2020. All general surgical emergency admissions to KAPVGMC and MGMGH, district general hospital were included from march to December 2020.The details of diagnosis and subsequent management were retrieved from records. CONCLUSION: It was observed thatclinical decisions were made based on urgency of each case while simultaneously evaluating their COVID 19 status. The number of surgicalcases during COVID 19 period were signicantly reduced. Recognising asymptomatic carriers and need of emergency surgical intervention were the challenges faced by the surgeons. Effective communication between microbiologist, radiologist, anaesthetist and surgeon was necessary to attain a favourable outcome. .Inspite of challenges faced 80% had postoperative uneventful period other than prolonged duration of stay and were discharged and followed up. Covid 19 pneumonia and ARDS attributed to majority of death among the 20 % of deceased , other than septicemia

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Biblical Criticism

Oxford Research Encyclopedia of Literature ◽

10.1093/acrefore/9780190201098.013.966 ◽

2021 ◽

Author(s):

Richard Briggs

Keyword(s):

21St Century ◽

Full Range ◽

Biblical Criticism ◽

Early 21St Century ◽

Authorial Intention ◽

The Bible ◽

Interpretive Method ◽

Interpretive Practices ◽

History Of Biblical Interpretation ◽

The Impact

The Bible as a text can be read with or without reference to its compilation as a theologically constructed collection of sacred Jewish and Christian books. When read without such framing concerns, it may be approached with the full range of literary and theoretical interpretive tools and read for whatever purpose readers value or wish to explore. Less straightforwardly, in the former case where framing concerns come into play, the Bible is both like and unlike any other book in the way that its very nature as a “canon” of scripture is related to particular theological and religious convictions. Such convictions are then in turn interested in configuring the kinds of readings pursued in certain ways. Biblical criticism has undergone many transformations over the centuries, sometimes allowing such theological convictions or practices to shape the nature of its criticism, and at other times—especially in the modern period—tending to relegate their significance in favor of concerns with interpretive method, and in particular questions about authorial intention, original context, and interest in matters of history (either in the world behind the text, or in the stages of development of the text itself). From the middle of the 20th century onwards the interpretive interests of biblical critics have focused more on certain literary characteristics of biblical narratives and poetry, and also a greater theological willingness to engage the imaginative vision of biblical texts. This has resulted in a move toward a theological form of criticism that might better be characterized as imaginative and invites explicit negotiation of readers’ identities and commitments. A sense of the longer, premodern history of biblical interpretation suggests that some of these late 20th- and early 21st-century emphases do themselves have roots in the interpretive practices of earlier times, but that the Reformation (and subsequent developments in modern thinking) effectively closed down certain interpretive options in the name of better ordering readers’ interpretive commitments. Though not without real gains, this narrowing of interpretive interests has resulted in much of the practice of academic biblical criticism being beholden to modernist impulses. Shifts toward postmodern emphases have been less common on the whole, but the overall picture of biblical criticism has indeed changed in the 21st century. This may be more owing to the impact of a renewed appetite for theologically imaginative readings among Christian readers, and also of the refreshed recognition of Jewish traditions of interpretation that pose challenging framing questions to other understandings.

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Adaptation and Psychometric Evaluation of the Parenting Concerns Questionnaire—Advanced Disease

American Journal of Hospice and Palliative Medicine® ◽

10.1177/10499091211049801 ◽

2021 ◽

pp. 104990912110498

Author(s):

Eliza M. Park ◽

Mian Wang ◽

Savannah M. Bowers ◽

Anna C. Muriel ◽

Paula K. Rauch ◽

...

Keyword(s):

Functional Status ◽

Advanced Cancer ◽

Internal Consistency ◽

Convergent Validity ◽

Advanced Disease ◽

Full Range ◽

Psychometric Evaluation ◽

Face Validity ◽

Concept Elicitation ◽

The Impact

Purpose: When patients with advanced cancer have minor children (age < 18), their health-related quality of life is closely linked to their concerns about the impact of progressive illness and death on their children. The Parenting Concerns Questionnaire (PCQ), a validated measure for parents with cancer, does not capture the full range of concerns in advanced cancer. The aim of this was study was to adapt and establish psychometrics for the PCQ for advanced disease (PCQ-AD). Methods: After generating an initial item-bank, we conducted concept elicitation interviews with clinicians (n = 8) and cognitive interviews with patients (n = 23) for face validity. New items addressed concerns about impact of parental death, making every moment count, communication, and financial impact of cancer on children. We administered 21 candidate items to 151 parents with advanced cancer. We conducted confirmatory factor analysis (CFA), calculated internal consistency, and assessed convergent and known-groups validity. Results: We removed 8 redundant items due to residual covariation between items. CFA of the 13-item PCQ-AD demonstrated satisfactory fit (CFI = 0.971, TLI = 0.966, RMSEA = 0.081) and high internal consistency (Cronbach’s alpha = 0.94, composite reliability = 0.95). The PCQ-AD demonstrated convergent validity and known-groups validity; patients with poor functional status reported higher scores than patients with better functional status (Cohen’s d = 0.56, p = 0.002). Conclusion: Adaptation of the PCQ yielded the addition of constructs important in advanced cancer. The PCQ-AD appears to be a reliable and valid measure of parenting concerns in advanced cancer, but future studies are needed to examine measure performance in diverse populations and responsiveness of the PCQ-AD to interventions.

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Candidates for multiple impact craters: popigai and chicxulub as seen by EGM08, a global 5'×5' gravitational model

Solid Earth Discussions ◽

10.5194/sed-2-69-2010 ◽

2010 ◽

Vol 2 (1) ◽

pp. 69-103 ◽

Cited By ~ 1

Author(s):

J. Klokočník ◽

J. Kostelecký ◽

I. Pešek ◽

P. Novák ◽

C. A. Wagner ◽

...

Keyword(s):

High Spatial Resolution ◽

Impact Craters ◽

Stokes Parameters ◽

Disturbing Potential ◽

Gravitational Model ◽

Secondary Crater ◽

Complete Set ◽

Multiple Impact ◽

The Impact ◽

Main Crater

Abstract. In 2008 the new Earth Gravitational Model (EGM08) was released. It contains a complete set of spherical harmonic coefficients of the Earth's gravitational potential (Stokes parameters) to degree 2190 and order 2159 that can be used for evaluation of various potential quantities with both the unprecedented accuracy and high spatial resolution. Two such quantities, the gravity anomaly and second-order radial derivative of the disturbing potential, were computed over selected areas with known impact craters. The displays of these derivatives for two such sites clearly show not only the strong circular-like features known to be associated with them but also other symmetrical structures which appear to make them multiple impact sites. At Popigai, Siberia, the secondary circular features fall in a line from the primary in the SE direction. At Chicxulub, Yucatán, there appears to be one secondary crater close to the primary in the NE direction, as well as possibly others in the vicinity of the main crater. Gravity information alone is not proof of the impact craters but it is useful in identifying candidate sites for further study, for future examination by geologists and geophysicists.

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