scholarly journals Assessment of Morphology Changes of the End Moraine of the Werenskiold Glacier (SW Spitsbergen) Using Active and Passive Remote Sensing Techniques

2021 ◽  
Vol 13 (11) ◽  
pp. 2134
Author(s):  
Tadeusz Głowacki ◽  
Damian Kasza
Keyword(s):  
Morphological Changes ◽  
Time Interval ◽  
Dynamic Surface ◽  
Near Surface ◽  
Passive Remote Sensing ◽  
Synthetic Aperture Radar Interferometry ◽  
Aerial Photogrammetry ◽  
Remote Sensing Techniques ◽  
One Year

Wedel Jarlsberg Land in Svalbard is a region with a varied periglacial landscape. In the mountains and in the valleys, the climate is polar with permafrost. During the summer, the near-surface ground layer thaws. The Werenskiold Glacier, together with its end moraine, are located in the central part of this area. The rate of morphological changes observed within the moraine varies in time and space, and depends on the environmental conditions. This study investigates four periods of archival aerial photogrammetry measurements (1936, 1960, 1990, and 2011) performed for the end moraine of the glacier. The long-term analysis was also based on a direct GNSS RTK survey from 2015. Over a period of almost 80 years, more than 14 million m3 of rock and ice material disappeared from the end moraine of the glacier (an average of approximately 200 thousand m3/year). Analyses of the dynamic surface changes over one year (2015) were performed with the use of synthetic aperture radar interferometry (InSAR). The time interval between images was in this case 12 days and covered (simultaneously in each scene) the entire investigated area. In this case, the analysis demonstrated that over a period of only 4 months, the moraine lost 200 thousand m3 of material (approximately two thousand m3/day), which is equivalent to the entire annual mass loss of the moraine.

scholarly journals Temporary Immunity and Multiple Waves of COVID-19

2020 ◽  
Author(s):  
B Shayak ◽  
Mohit M Sharma ◽  
Anoop Misra
Keyword(s):  
Mathematical Modeling ◽  
Contact Tracing ◽  
Time Interval ◽  
Current Time ◽  
Intervention Level ◽  
Effective Interventions ◽  
One Year ◽  
Parameter Values ◽  
Threshold Duration

ABSTRACTIn this work we use mathematical modeling to describe the potential phenomena which may occur if immunity to COVID-19 lasts for a finite time instead of being permanent, i.e. if a recovered COVID-19 patient may again become susceptible to the virus after a given time interval following his/her recovery. Whether this really happens or not is unknown at the current time. If it does happen, then we find that for certain combinations of parameter values (social mobility, contact tracing, immunity threshold duration etc), the disease can keep recurring in wave after wave of outbreaks, with a periodicity approximately equal to twice the immunity threshold. Such cyclical attacks can be prevented trivially if public health interventions are strong enough to contain the disease outright. Of greater interest is the finding that should such effective interventions not prove possible, then also the second and subsequent waves can be forestalled by a consciously relaxed intervention level which finishes off the first wave before the immunity threshold is breached. Such an approach leads to higher case counts in the immediate term but significantly lower counts in the long term as well as a drastically shortened overall course of the epidemic.As we write this, there are more than 1,00,00,000 cases (at least, detected cases) and more than 5,00,000 deaths due to COVID-19 all over the globe. The unknowns surrounding this disease outnumber the knowns by orders of magnitude. One of these unknowns is how long does immunity last i.e., once a person recovers from COVID-19 infection, how long does s/he remain insusceptible to a fresh infection. Most modeling studies assume lifetime immunity, or at least sufficiently prolonged immunity as to last until the outbreak is completely over. Among the exceptions are Giordano et. al. [1] and Bjornstad et. al. [2] who account for the possibility of re-infection – while the former find no special behaviour on account of this, the latter find an oscillatory approach towards the eventual equilibrium. In an article which appeared today, Kosinski [3] has found multiple waves of COVID-19 if the immunity threshold is finite. The question of whether COVID-19 re-infection can occur is completely open as of now. A study [4] has found that for benign coronaviruses (NOT the COVID-19 pathogen!), antibodies become significantly weaker six months after the original infection, and re-infection is common from one year onwards. Although it is currently unknown whether COVID-19 re-infections can occur, the mere possibility is sufficiently frightening as to warrant a discussion of what might happen if it is true. In this Article, we use mathematical modeling to present such a discussion. Before starting off, let us declare in the clearest possible terms that this entire Article is a what-if analysis, predicated on an assumption whose veracity is not known at the current time. The contents of this Article are therefore hypothetical – as of now they are neither factual nor counter-factual.

scholarly journals Are EARLINET and AERONET climatologies consistent? The case of Thessaloniki, Greece

2018 ◽  
Vol 18 (16) ◽  
pp. 11885-11903 ◽  
Author(s):  
Nikolaos Siomos ◽  
Dimitris S. Balis ◽  
Kalliopi A. Voudouri ◽  
Eleni Giannakaki ◽  
Maria Filioglou ◽  
...  
Keyword(s):  
Boundary Layer ◽  
A Priori ◽  
Free Troposphere ◽  
Climatological Data ◽  
Annual Cycles ◽  
Passive Remote Sensing ◽  
Dust Component ◽  
Remote Sensing Techniques ◽  
Sampling Schedule

Abstract. In this study we investigate the climatological behavior of the aerosol optical properties over Thessaloniki during the years 2003–2017. For this purpose, measurements of two independent instruments, a lidar and a sunphotometer, were used. These two instruments represent two individual networks, the European Lidar Aerosol Network (EARLINET) and the Aerosol Robotic Network (AERONET). They include different measurement schedules. Fourteen years of lidar and sunphotometer measurements were analyzed, independently of each other, in order to obtain the annual cycles and trends of various optical and geometrical aerosol properties in the boundary layer, in the free troposphere, and for the whole atmospheric column. The analysis resulted in consistent statistically significant and decreasing trends of aerosol optical depth (AOD) at 355 nm of −23.2 and −22.3 % per decade in the study period over Thessaloniki for the EARLINET and the AERONET datasets, respectively. Therefore, the analysis indicates that the EARLINET sampling schedule can be quite effective in producing data that can be applied to long-term climatological studies. It is also shown that the observed decreasing trend is mainly attributed to changes in the aerosol load inside the boundary layer. Seasonal profiles of the most dominant aerosol mixture types observed over Thessaloniki have been generated from the lidar data. The higher values of the vertically resolved extinction coefficient at 355 nm appear in summer, while the lower ones appear in winter. The dust component is more dominant in the free troposphere than in the boundary layer during summer. The biomass burning layers tend to arrive in the free troposphere during spring and summer. This kind of information can be quite useful for applications that require a priori aerosol profiles. For instance, they can be utilized in models that require aerosol climatological data as input, in the development of algorithms for satellite products, and also in passive remote-sensing techniques that require knowledge of the aerosol vertical distribution.

scholarly journals Eddy-Induced Particle Dispersion in the Near-Surface North Atlantic

2012 ◽  
Vol 42 (12) ◽  
pp. 2206-2228 ◽  
Author(s):  
Irina I. Rypina ◽  
Igor Kamenkovich ◽  
Pavel Berloff ◽  
Lawrence J. Pratt
Keyword(s):  
North Atlantic ◽  
Particle Dispersion ◽  
Material Transport ◽  
Near Surface ◽  
The Mean ◽  
Surface Drifters ◽  
Particle Spreading ◽  
One Year ◽  
Ekman Advection

Abstract This study investigates the anisotropic properties of the eddy-induced material transport in the near-surface North Atlantic from two independent datasets, one simulated from the sea surface height altimetry and one derived from real-ocean surface drifters, and systematically examines the interactions between the mean- and eddy-induced material transport in the region. The Lagrangian particle dispersion, which is widely used to characterize the eddy-induced tracer fluxes, is quantified by constructing the “spreading ellipses.” The analysis consistently demonstrates that this dispersion is spatially inhomogeneous and strongly anisotropic. The spreading is larger and more anisotropic in the subtropical than in the subpolar gyre, and the largest ellipses occur in the Gulf Stream vicinity. Even at times longer than half a year, the spreading exhibits significant nondiffusive behavior in some parts of the domain. The eddies in this study are defined as deviations from the long-term time-mean. The contributions from the climatological annual cycle, interannual, and subannual (shorter than one year) variability are investigated, and the latter is shown to have the strongest effect on the anisotropy of particle spreading. The influence of the mean advection on the eddy-induced particle spreading is investigated using the “eddy-following-full-trajectories” technique and is found to be significant. The role of the Ekman advection is, however, secondary. The pronounced anisotropy of particle dispersion is expected to have important implications for distributing oceanic tracers, and for parameterizing eddy-induced tracer transfer in non-eddy-resolving models.

scholarly journals Radiological evaluation of pulmonary sequelae in COVID-19

ANALES RANM ◽  
2020 ◽  
Vol 137 (137(03)) ◽  
pp. 298-304
Author(s):  
Carlos F Muñoz-Núñez ◽  
Pilar Calvillo-Batllés ◽  
Enrique Zaldívar Olmeda ◽  
Vicente Belloch Ripollés ◽  
Luis Martí-Bonmatí
Keyword(s):  
Severe Acute Respiratory Syndrome ◽  
Viral Infection ◽  
Scientific Knowledge ◽  
Morphological Changes ◽  
Target Organ ◽  
Radiological Evaluation ◽  
Vascular Changes ◽  
One Year

Coronavirus Disease 2019 (COVID-19) is a highly transmissible and pathogenic viral infection caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). The target organ is the lung. This infection appeared in Wuhan (China) in December 2019 and the WHO considered it a pandemic in March 2020. One year after the first known cases, and although there is a great amount of scientific knowledge acquired of the disease, there are still some unanswered questions. As a matter of fact, there is a lack of knowledge about which patients will suffer sequels, what kind of morphological changes and sequel types will be expected, nor the grade of functional severity. It is known that other coronavirus pneumoniae caused pulmonary sequels and therefore they are expected in COVID-19. In this work we review several COVID-19 aspects related with the development and grading of mid- and long-term pulmonary sequels, including fibrosis and vascular changes, and strengthen the role of medical imaging in this evaluation.

Comparative assessment of morphological mechanisms of maintaining structural liver homeostasis in the dynamics of exposure to coal-rock dust and sodium fluoride on the body

2020 ◽  
pp. 189-194
Author(s):  
M. S. Bugaeva ◽  
O. I. Bondarev ◽  
N. N. Mikhailova ◽  
L. G. Gorokhova
Keyword(s):  
Sodium Fluoride ◽  
Morphological Changes ◽  
The Body ◽  
System Level ◽  
Production Factor ◽  
Coal Rock ◽  
The Impact ◽  
Structural Homeostasis ◽  
Rock Dust

Introduction. The impact on the body of such factors of the production environment as coal-rock dust and fluorine compounds leads to certain shift s in strict indicators of homeostasis at the system level. Maintaining the relative constancy of the internal environment of the body is provided by the functional consistency of all organs and systems, the leading of which is the liver. Organ repair plays a crucial role in restoring the structure of genetic material and maintaining normal cell viability. When this mechanism is damaged, the compensatory capabilities of the organ are disrupted, homeostasis is disrupted at the cellular and organizational levels, and the development of the main pathological processes is noted.The aim of the study is to compare the morphological mechanisms of maintaining structural homeostasis of the liver in the dynamics of the impact on the body of coal-rock dust and sodium fluoride.Materials and methods. Experimental studies were conducted on adult white male laboratory rats. Features of morphological mechanisms for maintaining structural homeostasis of the liver in the dynamics of exposure to coal-rock dust and sodium fluoride were studied on experimental models of pneumoconiosis and fluoride intoxication. For histological examination in experimental animals, liver sampling was performed after 1, 3, 6, 9, 12 weeks of the experiment.Results. The specificity of morphological changes in the liver depending on the harmful production factor was revealed. It is shown that chronic exposure to coal-rock dust and sodium fluoride is characterized by the development of similar morphological changes in the liver and its vessels from the predominance of the initial compensatory-adaptive to pronounced violations of the stromal and parenchymal components. Long-term inhalation of coal-rock dust at 1–3 weeks of seeding triggers adaptive mechanisms in the liver in the form of increased functional activity of cells, formation of double-core hepatocytes, activation of immunocompetent cells and endotheliocytes, ensuring the preservation of the parenchyma and the general morphostructure of the organ until the 12th week of the experiment. Exposure to sodium fluoride leads to early disruption of liver compensatory mechanisms and the development of dystrophic changes in the parenchyma with the formation of necrosis foci as early as the 6th week of the experiment.Conclusions. The study of mechanisms for compensating the liver structure in conditions of long-term exposure to coal-rock dust and sodium fluoride, as well as processes that indicate their failure, and the timing of their occurrence, is of theoretical and practical importance for developing recommendations for the timely prevention and correction of pathological conditions developing in employees of the aluminum and coal industry.The authors declare no conflict of interests.

scholarly journals A206 EVOLUTION OF PEDIATRIC AUTOIMMUNE CHOLANGITIS AND PRIMARY SCLEROSING CHOLANGITIS INTO ADULTHOOD

2021 ◽  
Vol 4 (Supplement_1) ◽  
pp. 234-236
Author(s):  
P Willems ◽  
J Hercun ◽  
C Vincent ◽  
F Alvarez
Keyword(s):  
Primary Sclerosing Cholangitis ◽  
Sclerosing Cholangitis ◽  
Response To Treatment ◽  
Similar Proportion ◽  
Autoimmune Cholangitis ◽  
Significant Difference ◽  
One Year ◽  
Liver Tests

Abstract Background The natural history of primary sclerosing cholangitis (PSC) in children seems to differ from PSC in adults. However, studies on this matter have been limited by short follow-up periods and inconsistent classification of patients with autoimmune cholangitis (AIC) (or overlap syndrome). Consequently, it remains unclear if long-term outcomes are affected by the clinical phenotype. Aims The aims of this is study are to describe the long-term evolution of PSC and AIC in a pediatric cohort with extension of follow-up into adulthood and to evaluate the influence of phenotype on clinical outcomes. Methods This is a retrospective study of patients with AIC or PSC followed at CHU-Sainte-Justine, a pediatric referral center in Montreal. All charts between January 1998 and December 2019 were reviewed. Patients were classified as either AIC (duct disease on cholangiography with histological features of autoimmune hepatitis) or PSC (large or small duct disease on cholangiography and/or histology). Extension of follow-up after the age of 18 was done for patients followed at the Centre hospitalier de l’Université de Montréal. Clinical features at diagnosis, response to treatment at one year and liver-related outcomes were compared. Results 40 patients (27 PSC and 13 AIC) were followed for a median time of 71 months (range 2 to 347), with 52.5% followed into adulthood. 70% (28/40) had associated inflammatory bowel disease (IBD) (78% PSC vs 54% AIC; p=0.15). A similar proportion of patients had biopsy-proven significant fibrosis at diagnosis (45% PSC vs 67% AIC; p=0.23). Baseline liver tests were similar in both groups. At diagnosis, all patients were treated with ursodeoxycholic acid. Significantly more patients with AIC (77% AIC vs 30 % PSC; p=0.005) were initially treated with immunosuppressive drugs, without a significant difference in the use of Anti-TNF agents (0% AIC vs 15% PSC; p= 0.12). At one year, 55% (15/27) of patients in the PSC group had normal liver tests versus only 15% (2/13) in the AIC group (p=0.02). During follow-up, more liver-related events (cholangitis, liver transplant and cirrhosis) were reported in the AIC group (HR=3.7 (95% CI: 1.4–10), p=0.01). Abnormal liver tests at one year were a strong predictor of liver-related events during follow-up (HR=8.9(95% CI: 1.2–67.4), p=0.03), while having IBD was not (HR=0.48 (95% CI: 0.15–1.5), p=0.22). 5 patients required liver transplantation with no difference between both groups (8% CAI vs 15% CSP; p=0.53). Conclusions Pediatric patients with AIC and PSC show, at onset, similar stage of liver disease with comparable clinical and biochemical characteristics. However, patients with AIC receive more often immunosuppressive therapy and treatment response is less frequent. AIC is associated with more liver-related events and abnormal liver tests at one year are predictor of bad outcomes. Funding Agencies None

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