Oxygen deficiency impacts on burying habitats for lesser sandeel, Ammodytes tobianus, in the inner Danish waters

2009 ◽  
Vol 66 (6) ◽  
pp. 883-895 ◽  
Author(s):  
Jane W. Behrens ◽  
Gunni Ærtebjerg ◽  
Jens Kjerulf Petersen ◽  
Jacob Carstensen
Keyword(s):  
Oxygen Saturation ◽  
Temperature Increase ◽  
Regional Differences ◽  
Oxygen Deficiency ◽  
Open Water ◽  
Monitoring Data ◽  
Interannual Variations ◽  
Sediment Composition ◽  
Temporal Interpolation ◽  
Bottom Oxygen

Starting in 1980s, the inner Danish waters have yearly been exposed to seasonal oxygen deficiency (hypoxia). Through spatial–temporal interpolation of monitoring data (1998–2005), we investigated oxygen deficiency impacts on suitable burying habitats for lesser sandeel ( Ammodytes tobianus ). Furthermore, the consequences of a predicted 4 °C temperature increase within this century were investigated. Maps of bottom oxygen deficiency (oxygen saturation ≤ Scrit of sandeel) were overlaid on maps of sediment composition. Throughout the study period (1998–2005), about 8% of the suitable sediments were affected by oxygen deficiency during an average year and 23% in the most severe year. Regional differences underlay the interannual variations. The extent of oxygen deficiency in enclosed regions varied from 20% to 33% of the suitable seabed being affected, whereas in open-water regions oxygen deficiency problems were limited during average years. However, large areas of the open-water seabed experienced oxygen deficiency during severe years. In such years, under a 4.0 °C temperature increase scenario, the extent of oxygen deficiency on open-water suitable patches was predicted to increase from 25% to about 40%.

Longitudinal Analysis of Continuous Pulse Oximetry as Prognostic Factor in Neonatal Respiratory Distress

2020 ◽  
Author(s):  
Gonzalo Solís-García ◽  
Elena Maderuelo-Rodríguez ◽  
Teresa Perez-Pérez ◽  
Laura Torres-Soblechero ◽  
Ana Gutiérrez-Vélez ◽  
...  
Keyword(s):  
Heart Rate ◽  
Intensive Care ◽  
Respiratory Distress ◽  
Oxygen Saturation ◽  
Continuous Monitoring ◽  
Vital Signs ◽  
Epidemiological Data ◽  
Monitoring Data ◽  
Joint Models ◽  
Neonatal Icu

Objective Analysis of longitudinal data can provide neonatologists with tools that can help predict clinical deterioration and improve outcomes. The aim of this study is to analyze continuous monitoring data in newborns, using vital signs to develop predictive models for intensive care admission and time to discharge. Study Design We conducted a retrospective cohort study, including term and preterm newborns with respiratory distress patients admitted to the neonatal ward. Clinical and epidemiological data, as well as mean heart rate and saturation, at every minute for the first 12 hours of admission were collected. Multivariate mixed, survival and joint models were developed. Results A total of 56,377 heart rate and 56,412 oxygen saturation data were analyzed from 80 admitted patients. Of them, 73 were discharged home and 7 required transfer to the intensive care unit (ICU). Longitudinal evolution of heart rate (p < 0.01) and oxygen saturation (p = 0.01) were associated with time to discharge, as well as birth weight (p < 0.01) and type of delivery (p < 0.01). Longitudinal heart rate evolution (p < 0.01) and fraction of inspired oxygen at admission at the ward (p < 0.01) predicted neonatal ICU (NICU) admission. Conclusion Longitudinal evolution of heart rate can help predict time to transfer to intensive care, and both heart rate and oxygen saturation can help predict time to discharge. Analysis of continuous monitoring data in patients admitted to neonatal wards provides useful tools to stratify risks and helps in taking medical decisions. Key Points

Temporal and Spatial Dynamics in Riverbed Chemistry: The Influence of Flow and Sediment Composition

1992 ◽  
Vol 49 (10) ◽  
pp. 2128-2140 ◽  
Author(s):  
P. A. Chambers ◽  
E. E. Prepas ◽  
K. Gibson
Keyword(s):  
Large Scale ◽  
Discharge Rate ◽  
Spatial Dynamics ◽  
Size Composition ◽  
Open Water ◽  
Spatial And Temporal Variability ◽  
Sediment Composition ◽  
Nitrogen And Phosphorus ◽  
Nutrient Pool ◽  
Fine Sediments

To characterize the nutrient pool in the riverbed of an unregulated river in western Canada and identify factors controlling spatial and temporal variability, nitrogen and phosphorus concentrations in open water, porewater, and sediment-exchangeable pools were monitored in the Pembina River, Alberta, at three sites that differed in sediment composition (cobble, sand, and fine sediments). Comparison of porewater chemistry for three years showed that interannual variation was related to discharge rate (22, 87, and 68 m3/s for May–November 1988, 1989, and 1990, respectively) and changes in the size composition of the bottom sediments. However, within-year variations in riverbed chemistry were not correlated with either flow or current velocity. These results suggest that large-scale interannual changes in flow act as a set-point mechanism, defining the particle size composition and chemistry of the riverbed; flow changes of short duration had no predictable effect on riverbed chemistry. Our finding on the highly dynamic nature of riverbed chemistry has important implications for benthic productivity and elemental fluxes between surface waters and the riverbed because dramatic changes in riverbed chemistry can occur in the span of a year even without a flushing scour.

scholarly journals Application of Multiple NIRS Imaging Device to the Exercising Muscle Metabolism

2003 ◽  
Vol 17 (2-3) ◽  
pp. 549-558 ◽  
Author(s):  
Hajime Miura ◽  
Kevin McCully ◽  
Britton Chance
Keyword(s):  
Oxygen Saturation ◽  
Blood Volume ◽  
Regional Differences ◽  
Near Infrared ◽  
Plantar Flexion ◽  
Muscle Metabolism ◽  
Arterial Disease ◽  
Light Sources ◽  
Imaging Device ◽  
Peripheral Arterial

Near infrared spectroscopy (NIRS) is a developing technique that measures the balance between muscle oxygen consumption and oxygen supply that is noninvasive and potentially portable. Differential absorption of light in the 600−900 nm region detects the changes in small vessel hemoglobin oxygen saturation and blood volume. Recent developments include the combining of multiple light sources and photodetectors to provide “images” of oxygen saturation and blood volume of wide regions of muscle. Using multiple NIRS imaging device, we monitored localized muscle metabolism during various exercises in the field as well as in the laboratory. In healthy subjects, the regional differences in oxygen saturation and blood volume were detected in the medial head of the gastrocnemius muscle during a standing plantar flexion exercise, consistent with differences in intramuscular pressure. Patients with peripheral arterial disease (PAD) showed slower recovery for both oxygenation and blood volume after exercise. Treatment for PAD resulted in improvements in NIRS-measured recovery times. In summary, NIRS devices have the ability to detect and monitor impaired muscle circulation. In addition, NIRS devices with multiple channels have the potential to evaluate the regional differences in oxygen status. Multiple NIRS imaging devices have the potential to play an important role in monitoring exercise prescription and clinical uses.

scholarly journals Observing Muostakh disappear: permafrost thaw subsidence and erosion of a ground-ice-rich island in response to arctic summer warming and sea ice reduction

2015 ◽  
Vol 9 (1) ◽  
pp. 151-178 ◽  
Author(s):  
F. Günther ◽  
P. P. Overduin ◽  
I. A. Yakshina ◽  
T. Opel ◽  
A. V. Baranskaya ◽  
...  
Keyword(s):  
Sea Ice ◽  
Air Temperature ◽  
Open Water ◽  
Aerial Photographs ◽  
The Arctic ◽  
Interannual Variations ◽  
Ground Ice ◽  
Concentration Data ◽  
Water Fraction ◽  
Permafrost Thaw

Abstract. Observations of coastline retreat using contemporary very high resolution satellite and historical aerial imagery were compared to measurements of open water fraction, summer air temperature, and wind. We analysed seasonal and interannual variations of thawing-induced cliff top retreat (thermo-denudation) and marine abrasion (thermo-abrasion) on Muostakh Island in the southern central Laptev Sea. Geomorphometric analysis revealed that total ground ice content on Muostakh is made up of equal amounts of intrasedimentary and macro ground ice and sums up to 87%, rendering the island particularly susceptible to erosion along the coast, resulting in land loss. Based on topographic reference measurements during field campaigns, we generated digital elevation models using stereophotogrammetry, in order to block-adjust and orthorectify aerial photographs from 1951 and GeoEye, QuickBird, WorldView-1, and WorldView-2 imagery from 2010 to 2013 for change detection. Using sea ice concentration data from the Special Sensor Microwave Imager (SSM/I) and air temperature time series from nearby Tiksi, we calculated the seasonal duration available for thermo-abrasion, expressed as open water days, and for thermo-denudation, based on the number of days with positive mean daily temperatures. Seasonal dynamics of cliff top retreat revealed rapid thermo-denudation rates of −10.2 ± 4.5 m a−1 in mid-summer and thermo-abrasion rates along the coastline of −3.4 ± 2.7 m a−1 on average during the 2010–2013 observation period, currently almost twice as rapid as the mean rate of −1.8 ± 1.3 m a−1 since 1951. Our results showed a close relationship between mean summer air temperature and coastal thermo-erosion rates, in agreement with observations made for various permafrost coastlines different to the East Siberian Ice Complex coasts elsewhere in the Arctic. Seasonality of coastline retreat and interannual variations of environmental factors suggest that an increasing length of thermo-denudation and thermo-abrasion process simultaneity favours greater coastal erosion. Coastal thermo-erosion has reduced the island's area by 0.9 km2 (24%) over the past 62 years but shrank its volume by 28 x 106 m3 (40%), not least because of permafrost thaw subsidence, with the most pronounced with rates of &amp;geq;− 11 cm a−1 on yedoma uplands near the island's rapidly eroding northern cape. Recent acceleration in both will halve Muostakh Island's lifetime to less than a century.

scholarly journals Observing Muostakh Island disappear: erosion of a ground-ice-rich coast in response to summer warming and sea ice reduction on the East Siberian shelf

2013 ◽  
Vol 7 (4) ◽  
pp. 4101-4176 ◽  
Author(s):  
F. Günther ◽  
P. P. Overduin ◽  
A. Baranskaya ◽  
T. Opel ◽  
M. N. Grigoriev
Keyword(s):  
Sea Ice ◽  
Air Temperature ◽  
Open Water ◽  
The Arctic ◽  
Historical Period ◽  
Interannual Variations ◽  
Ground Ice ◽  
Concentration Data ◽  
Sea Ice Concentration ◽  
Ice Complex

Abstract. Observations of coastline retreat using contemporary very high resolution satellite and historical aerial imagery were compared to measurements of open water fractions and summer air temperatures. We analyzed seasonal and interannual variations of thawing-induced cliff top retreat (thermo-denudation) and marine abrasion (thermo-abrasion) on Muostakh Island in the southern central Laptev Sea. The island is composed of ground-ice-rich permafrost deposits of Ice Complex type that render it particularly susceptible to erosion along the coast, resulting in land loss. Based on topographic reference measurements during field campaigns, we generated digital elevation models using stereophotogrammetry, in order to block adjust and ortho-rectify aerial photographies from 1951 and GeoEye, QuickBird, WorldView-1, and WorldView-2 imagery from 2010 to 2012 for change detection. Coastline retreat for erosive segments ranged from −13 to −585 m and was −109 ± 81 m (–1.8 ± 1.3 m a−1) on average during the historical period. Current seasonal dynamics of cliff top retreat revealed rapid thermo-denudation rates of –10.2 ± 4.5 m a−1 in mid summer and –4.1 ± 2.0 m a−1 on average during the 2010–2012 observation period. Using sea ice concentration data from the Special Sensor Microwave Imager (SSM/I) and air temperature time series from Tiksi, we calculated seasonal duration available for thermo-abrasion, expressed as open water days, and for thermo-denudation, based on thawing degree days. Geomorphometric analysis revealed that total ground ice content on Muostakh is made up of equal amounts of intrasedimentary and macro ground ice, while its vertical hourglass distribution provides favorable local preconditions for subsidence and the acceleration of coastal thermo-erosion under intensifying environmental forcings. Our results showed a~close relationship between mean summer air temperature and coastal thermo-erosion rates, in agreement with observations made for various permafrost coastlines different from East Siberian Ice Complex coasts elsewhere in the Arctic. Seasonality and recent interannual variations of coastline retreat rates suggest that the combination of macro ground ice distribution in the ground and changes in enviromental forcing generate a cyclicity in coastal thermo-erosion, that is currently increasing in frequency.

scholarly journals The Participation of the Organism Adaptation Mechanisms to the Lack of Oxygen According to the Assessment of the Fethemoglobin Content in the Peripheral Blood of Patients with Community-acquired Pneumonia

2021 ◽  
Vol 2-3 (35-36) ◽  
pp. 44-49
Author(s):  
V. Bereznyakov ◽  
Keyword(s):  
Oxygen Saturation ◽  
Peripheral Blood ◽  
Oxygen Deficiency ◽  
Fetal Hemoglobin ◽  
Community Acquired Pneumonia ◽  
Control Group ◽  
External Respiration ◽  
Healthy Individuals ◽  
Adaptation Mechanisms ◽  
Oxygen Transport System

Introduction. Сommunity-acquired pneumonia (COP) is a global socio-medical problem. At emergence of pneumonia by any genesis, hypoxia develops. Oxygen homeostasis of the body is provided by the coordinated interaction of external respiration, circulatory system and oxygen-transport system of the blood. Hypoxia, due to the malfunction of the external respiratory system, causes the formation of compensatory changes, in the implementation of which involved components of the oxygen transport system. Molecular genetic mechanisms play an important role in the body's adaptation to oxygen deficiency. Fetal hemoglobin (FetHb), having an increased affinity for oxygen, makes a significant contribution to the body's adaptation to new conditions with altered gaseous environment in the presence of pathological processes occurring with hypoxia. In this regard, it is interest to determine FetHb in adults with COP to study its effect on the diagnosis, prognosis and outcome of the disease. The aim of the study. To determinate the participation of the organism adaptation mechanisms to the lack of oxygen according to the assessment of the content of fetal hemoglobin in the peripheral blood of patients with community-acquired pneumonia. Materials and methods. We examined 34 adult patients (18 women and 16 men) with COP, aged 18 to 80 years, who were in the therapeutic department of the City Clinical Hospital № 25 in Kharkiv. The control group was formed of 20 healthy individuals. Spirography was performed on the diagnostic complex "Valenta"; hematological examinations – on the analyzer "ADVIA 60"; measurement of pO2 and pCO2, oxygen saturation, content of fetal hemoglobin – on the device "RAPIDLAB865". Results. In patients with community-acquired pneumonia, there was a decrease of the ventilatory function of external respiration, which is confirmed by a marked decrease in partial oxygen pressure. Oxygen saturation of blood was reduced in the group of patients with COP, but the difference was not statistically significant 94.8 ± 1.0 %. This indicates the presence of compensatory mechanisms aimed at maintaining adequate blood oxygen saturation. Significant increase in pH (from 7.40 to 7.53) and decrease in standard bicarbonate (from 1.27 to 0.68 mmol/l) resulting from violation of the gas composition of the blood can be regarded as a manifestation of partially compensated respiratory alkalosis. In patients with COP, there was a reduction in the total time of hemolysis, a shift of the maximum erythrogram to the left and an increase in the maximum itself, indicating a sharp decline in erythrocyte resistance. The proportion of erythrocytes with reduced resistance was twice as large as similar forms in the control group and the number of highly resistant cells in patients with COP sharply decreased. Obviously, oxygen starvation-mediated stress erythropoiesis is accompanied by the entry into the circulation of functionally defective erythrocytes. They are subject to accelerated elimination from the vascular bed, which causes a decrease in the quantitative indicators of red blood (erythrocyte content, hemoglobin) while maintaining corpuscular parameters (Mean Corpuscular Volume, Mean Cell Hemoglobin Concentration). At the same time, the analysis of individual hemoglobin fractions revealed an increase in the proportion of fetal hemoglobin (from 2.90 ± 0.31 % in the group of healthy individuals to 5.43 ± 1.05 % in patients with COP) (p less than 0.05). Conclusions. Changes in the parameters of acid hemolysis, fetal hemoglobin in the peripheral blood of patients with community-acquired pneumonia with impaired pulmonary ventilation function indicate their participation in the mechanisms of adaptation to oxygen deficiency and they have informative potential. Elevated fetal hemoglobin in peripheral blood in these patients can be used as an indicator of hypoxia, accompanied by impaired oxygen delivery to tissues, which should be used as an additional criterion for diagnosing tissue hypoxia and justify the timely appointment of antihypoxia drugs. Keywords: hypoxia, community-acquired pneumonia, red blood cells, fetal hemoglobin.

Oxygen lack as a possible cause of reactive hyperemia

1959 ◽  
Vol 197 (3) ◽  
pp. 613-616 ◽  
Author(s):  
Dewitt G. Crawford ◽  
Hilton M. Fairchild ◽  
Arthur C. Guyton
Keyword(s):  
Carbon Dioxide ◽  
Blood Flow ◽  
Oxygen Saturation ◽  
Oxygen Deficiency ◽  
Reactive Hyperemia ◽  
Venous Blood ◽  
Compensatory Mechanism ◽  
Control Value ◽  
Arterial Blood ◽  
Relationship Of

The relationship of blood flow through the hind leg of a dog to the gaseous content of the blood has been studied in 20 dogs by two different methods. In 15 dogs the oxygen saturation of the blood flowing through the leg was gradually changed by adding various amounts of venous blood to arterial blood. As the oxygen saturation decreased the blood flow increased—slowly at first, then progressively more rapidly as the oxygen levels fell lower and lower. Even though the oxygen saturation in most experiments was decreased to 30%, the total oxygen transported to the tissues each minute (O2 saturation times blood flow) decreased only to 75% of the control value. This showed that a definite compensatory mechanism exists, with an efficiency of about 65% for preventing tissue hypoxemia. In five animals the oxygen saturation of the blood was maintained constant while the dogs were allowed to breathe 20% carbon dioxide for an hour. By checking the blood flow every 10 minutes it was found that there was no increase in blood flow but rather in three of the animals a decrease to the extent of 35% of the control blood flow and in the remaining two no change. These studies indicate that oxygen deficiency might well be one of the causes of reactive hyperemia but that excess carbon dioxide probably is not involved.

Reflectance spectrophotometry for the assessment of gastroduodenal mucosal perfusion

1987 ◽  
Vol 252 (6) ◽  
pp. G797-G804 ◽  
Author(s):  
F. W. Leung ◽  
T. Morishita ◽  
E. H. Livingston ◽  
T. Reedy ◽  
P. H. Guth
Keyword(s):  
Blood Flow ◽  
Oxygen Saturation ◽  
Regional Differences ◽  
Hemoglobin Concentration ◽  
Mucosal Blood Flow ◽  
Celiac Artery ◽  
Artery Occlusion ◽  
Reflectance Spectrophotometry ◽  
Vein Occlusion ◽  
Mucosal Perfusion

Reflectance spectrophotometry in assessing gastroduodenal mucosal perfusion was evaluated. Ischemia without congestion, e.g., during hemorrhagic hypotension or celiac artery occlusion, was associated with a reduction in the indexes of mucosal hemoglobin concentration and of oxygen saturation. Ischemia with congestion, e.g., during portal vein occlusion, or in absolute ethanol or suction-induced mucosal lesions, was associated with an increase in the index of mucosal hemoglobin concentration but a reduction in the index of oxygen saturation. An increase in the index of mucosal hemoglobin concentration associated with a normal index of oxygen saturation was found in the postischemic hyperemia after release of celiac artery occlusion and during the sustained increase in corpus mucosal blood flow induced by vagus nerve stimulation. Thus reflectance spectrophotometric measurements reflected ischemia, without or with congestion, and hyperemia. Additionally, although regional differences in reflectance spectrophotometric measurements were demonstrated in the duodenal, antral, and corpus mucosa, such differences bore no consistent relationship to regional differences in blood flow demonstrated in previous studies.

scholarly journals Regional Differences in Cuticular Permeability in the Desert Cicada Diceroprocta Apache: Implications for Evaporative Cooling

1989 ◽  
Vol 141 (1) ◽  
pp. 219-230 ◽  
Author(s):  
NEIL F. HADLEY ◽  
ERIC C. TOOLSON ◽  
MICHAEL C. QUINLAN
Keyword(s):  
Body Temperature ◽  
Water Loss ◽  
Temperature Increase ◽  
Regional Differences ◽  
Water Flux ◽  
Dorsal Surface ◽  
Male And Female ◽  
Cuticular Permeability ◽  
Higher Temperature

The cuticular permeability of the desert cicada Diceroprocta apache was measured in vivo from three regions of the dorsal surface: (1) the midline of the thorax (= dorsal thorax), a region that contains large pores (7–8 μm in diameter) located in a central tract; (2) the lateral thorax, a region in which large pores are absent, and (3) the midline of the abdomen, a region in which large pores are uniformly distributed over the surface. Transcuticular water flux rates were similar for all three areas at 27.0°C; however, at 41.5°C rates increased sharply for the dorsal thorax and abdomen, with tracings showing numerous irregular peaks that represent cycles of water extrusion. Transcuticular water flux for the lateral thorax, in contrast, was relatively unaffected by the temperature increase and the tracings remained relatively flat. Death of the animal at the higher temperature resulted in a significant decrease in water loss rates and a loss of the cycling pattern in both the dorsal thorax and abdomen, whereas water loss through the lateral thorax did not change. The active extrusion of water begins at 39.2-39.3°Cin both male and female cicadas. Our findings confirm that the large pores are the routes by which water reaches the surface and that the temperature at which this active extrusion of water begins corresponds to the point where cicadas must seek milder microclimates to prevent body temperature from reaching lethal levels.

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