scholarly journals The isotopic record at an alpine glacier and its implications for local climatic changes and isotopic homogenization processes

2001 ◽  
Vol 47 (156) ◽  
pp. 147-151 ◽  
Author(s):  
He Yuanqing ◽  
Wilfred H. Theakstone ◽  
Yao Tandong ◽  
Shi Yafeng
Keyword(s):  
Equilibrium Line Altitude ◽  
Temperature Variations ◽  
Alpine Glacier ◽  
Temperature Changes ◽  
Natural Factors ◽  
Air Temperatures ◽  
Regional Temperature ◽  
The Mean ◽  
A Site ◽  
The Relationship

AbstractStratigraphic variations of oxygen isotopes in the snow which accumulates during the winter at the Norwegian glacier Austre Okstindbreen are not entirely eliminated after 1–2 months of ablation in the following summer. The relationship between regional temperature changes and δ18O values in the snowpack is affected by many natural factors, but 1989/90 winter air temperatures were reflected in the snow which remained on Austre Okstindbreen at 1350 m a.s.l. in July 1990. There were many variations of δ18O values in the 4.1m of snow above the 1989 summer surface, but variations in the underlying firn were relatively small. Meltwater percolation modifies the initial variations of δ18O values in the snowpack. At a site below the mean equilibrium-line altitude on Austre Okstindbreen, increased isotopic homogenization within a 10 day period in July accompanied an increase of the mean δ18O value. Although the isotopic record at a temperate glacier is likely to be influenced by more factors than is that at polar glaciers, it can provide an estimate of the approximate trend of local temperature variations.

scholarly journals Winter-Season Climatic Signals in the Recently Deposited Snowpack on a Norwegian Alpine Glacier

2002 ◽  
Vol 33 (2-3) ◽  
pp. 111-122 ◽  
Author(s):  
He Yuanqing ◽  
Wilfred H. Theakstone ◽  
Yao Tandong ◽  
Cheng Guodong ◽  
Zhang Dian ◽  
...  
Keyword(s):  
Winter Season ◽  
Equilibrium Line Altitude ◽  
Alpine Glacier ◽  
Temperature Changes ◽  
Air Temperatures ◽  
Vertical Variations ◽  
Regional Temperature ◽  
The Mean ◽  
A Site ◽  
The Relationship

Vertical variations of oxygen isotopes in the snow which accumulates during the winter at the Norwegian glacier Austre Okstindbreen are not entirely eliminated after 1-2 months of ablation in the following summer. Survival of isotopic signals closely relates to the re-freezing capacity of snow accumulated in winter when its temperature was below 0°C. The meltwater re-freezes in layers formed in winter hindered subsequent meltwater percolation in summer when snow temperature was at melting point and, therefore, varied isotopic record was reserved between these ice layers. The isotopic record in snowpack can provide an estimate of the approximate trend of the most recent winter season temperatures. The relationship between regional temperature changes and б18O values in the snowpack is affected by many natural factors, but 1989-90 (a glacier balance year) winter air temperatures were reflected in the snow which remained on the glacier Austre Okstindbreen at an altitude of 1,350 m in July 1990. There was larger amplitude of variations of б 18O values in the 4.1 m of snow above the 1989 summer surface, but variations in the underlying firn were relatively small. Meltwater percolation modifies the initial variations of б 18O values in the snowpack. At a site below the mean equilibrium line altitude on Austre Okstindbreen, increased isotopic homogenization within a ten-day period in July accompanied an increase of the mean б 18O value. Although the isotopic record at a temperate glacier is likely to be influenced by more factors than is that at polar glaciers, it can provide an estimate of the approximate trend of recent local temperature variations.

scholarly journals Influence of air temperature on a glacier’s active-layer temperature

2006 ◽  
Vol 43 ◽  
pp. 285-291 ◽  
Author(s):  
V. Zagorodnov ◽  
O. Nagornov ◽  
L.G. Thompson
Keyword(s):  
Active Layer ◽  
Air Temperature ◽  
Seasonal Temperature ◽  
Temperature Variations ◽  
Surface Conditions ◽  
Tropical Glaciers ◽  
Air Temperatures ◽  
Screen Level ◽  
The Mean

AbstractSeasonal temperature variations occur in the glacier layer about 15–20 m below the surface, while at greater depths the glacier temperature depends on the long-term surface conditions. It is generally accepted that for glaciers without surface melting the temperature at 10 m depth (T10) is close to the mean annual air temperature at standard screen level (Ta), i.e. T10 =Ta. We found that this relationship is not valid for Ta above –17˚C and below –55˚C. The goal of our investigation is to find a better temperature transfer function (TTF) between Ta and temperature at the boundary of the active layer in accumulation areas of polar and tropical glaciers. Low-precision T10 temperatures from boreholes, obtained at 41 sites, are compared with air temperatures (Ta) measured in the vicinity of these sites for at least a 1 year period. We determine that when Ta falls into the temperature range –60 to –7˚C, empirical values can be approximated as T10 = 1:2Ta + 6:7. Analysis of these data suggests that high T10 occurs in the areas of the glacier that collect meltwater.

scholarly journals Does weather affect the growth rate of COVID-19, a study to comprehend transmission dynamics on human health

2020 ◽  
Author(s):  
Arjun Sil ◽  
Vanapalli Naveen Kumar
Keyword(s):  
Growth Rate ◽  
Transmission Rate ◽  
Environmental Parameters ◽  
Transmission Dynamics ◽  
Temperature Changes ◽  
Daily Rate ◽  
The Mean ◽  
Novel Coronavirus ◽  
Short Time ◽  
The Relationship

AbstractThe undefendable outbreak of novel coronavirus (SARS-COV-2) lead to a global health emergency due to its higher transmission rate and longer symptomatic duration, created a health surge in a short time. Since Nov 2019 the outbreak in China, the virus is spreading exponentially everywhere. The current study focuses on the relationship between environmental parameters and the growth rate of COVID-19. The statistical analysis suggests that the temperature changes retarded the growth rate and found that −6.28°C and +14.51°C temperature is the favorable range for COVID-19 growth. Gutenberg-Richter’s relationship is used to estimate the mean daily rate of exceedance of confirmed cases concerning the change in temperature. Temperature is the most influential parameter that reduces the growth at the rate of 13–16 cases/day with a 1°C rise in temperature.

scholarly journals Application of Nucleation Theory to the Process of Droplet Freezing on an Ice Substrate

1978 ◽  
Vol 21 (85) ◽  
pp. 705-705
Author(s):  
L. Levi
Keyword(s):  
Crystal Size ◽  
Approximate Expression ◽  
Growth Conditions ◽  
Nucleation Theory ◽  
Free Energies ◽  
Ice Surface ◽  
Air Temperatures ◽  
The Mean ◽  
Interfacial Free Energies ◽  
The Relationship

AbstractThe probability P that ice embryos, nucleated inside droplets colliding with an ice surface, have crystallographic orientations different from that of the substrate, is correlated with the mean number of droplets which form each crystal in accretions grown in dry regime (substrate temperature Ts < 0°C). The theory of heterogeneous nucleation is applied to represent the ice embryo nucleation rate and the approximate expression is obtained, where ΔGy* is the nucleation energy for randomly oriented critical embryos. Assuming cap-shaped embryos and taking into account the crystal size in accretions grown at Ts = —15°C and air temperatures , it is found that ergThe relationship between the value of ΔGy* and those of the crystal-embryo and crystal-melt interfacial free energies is discussed. Finally the dependence of P0 on the growth conditions and on the ice substrate orientation is analysed, considering the effect of embryo breeding by collision and that of orientation selection, which is responsible for the establishment of preferential orientations in the accretions.

scholarly journals Changes in thermal and precipitation conditions in Poland in 1971–2010

2014 ◽  
Vol 46 (2) ◽  
pp. 153-162 ◽  
Author(s):  
Barbara Skowera ◽  
Joanna Kopcińska ◽  
Bogumiła Kopeć
Keyword(s):  
Air Temperature ◽  
Agricultural Sector ◽  
Statistical Significance ◽  
Monthly Precipitation ◽  
Temporal And Spatial Variation ◽  
Temperature Changes ◽  
Air Temperatures ◽  
The Mean ◽  
Temporal And Spatial ◽  
Meteorological Elements

Abstract Changes in thermal and precipitation conditions in Poland in 1971-2010. The article presents changes in thermal and precipitation conditions on Polish territory in the years 1971- -2010 based on data from six meteorological stations (Koszalin, Olsztyn, Poznań, Lublin, Opole and Kraków). These data concern the monthly average air temperature, precipitation and the number of days with precipitation per month. Based on the analysis of changing trends in the study of meteorological elements, authors observed an increase in the mean annual air temperature of about 0.9°C over 10 years in all localities. In contrast, trends in the average monthly air temperatures were characterised by temporal and spatial variation. As a result of the increase in temperature, there was a change in the dates signifying the beginning and the end of the thermal periods: farming (OG), vegetation (OW), intensive vegetation (OIW) and maturation or thermal summers (OD/L). A tendency for these periods to start earlier was noted. Statistically significant changes were found for the following periods: vegetation in Koszalin and Olsztyn, intensive vegetation at all stations and thermal summer only in Lublin. An increasingly later end to these periods was noted, and statistically significant trends were found for the dates of the end of the following periods: maturation (thermal summer) at all stations except Opole, intensive vegetation in Poznań and Lublin and vegetation in Lublin and Opole. Seasonal and monthly precipitation totals in the years 1971-2010 were characterised by cyclicality. Significant upward trends were found only in the case of monthly precipitation totals in August in Koszalin and the sum of precipitation in the cooler half of the year in Poznań. In contrast, there was more days with precipitation at all stations included in the study, but the statistical significance of trends varied by location. Changes in thermal and precipitation conditions were accompanied by, among other factors, an increase in temperature, changes in the length of thermal periods and an increase in the frequency of rainfall. All of this is important information for the agricultural sector regarding changing crop conditions

scholarly journals Application of Nucleation Theory to the Process of Droplet Freezing on an Ice Substrate

1978 ◽  
Vol 21 (85) ◽  
pp. 705
Author(s):  
L. Levi
Keyword(s):  
Crystal Size ◽  
Approximate Expression ◽  
Growth Conditions ◽  
Nucleation Theory ◽  
Free Energies ◽  
Ice Surface ◽  
Air Temperatures ◽  
The Mean ◽  
Interfacial Free Energies ◽  
The Relationship

Abstract The probability P that ice embryos, nucleated inside droplets colliding with an ice surface, have crystallographic orientations different from that of the substrate, is correlated with the mean number of droplets which form each crystal in accretions grown in dry regime (substrate temperature T s &lt; 0°C). The theory of heterogeneous nucleation is applied to represent the ice embryo nucleation rate and the approximate expression is obtained, where ΔG y * is the nucleation energy for randomly oriented critical embryos. Assuming cap-shaped embryos and taking into account the crystal size in accretions grown at T s = —15°C and air temperatures , it is found that erg The relationship between the value of ΔG y * and those of the crystal-embryo and crystal-melt interfacial free energies is discussed. Finally the dependence of P 0 on the growth conditions and on the ice substrate orientation is analysed, considering the effect of embryo breeding by collision and that of orientation selection, which is responsible for the establishment of preferential orientations in the accretions.

Over-winter survival of first-stage larvae ofParelaphostrongylus tenuis (Nematoda: Protostrongylidae)

1998 ◽  
Vol 76 (4) ◽  
pp. 704-710 ◽  
Author(s):  
Sean G Forrester ◽  
Murray W Lankester
Keyword(s):  
Snow Cover ◽  
Reproductive Potential ◽  
Thunder Bay ◽  
Winter Conditions ◽  
Air Temperatures ◽  
Northern Areas ◽  
Wintering Area ◽  
The Mean ◽  
A Site ◽  
Different Levels

This study examined the ability of first-stageParelaphostrongylus tenuis larvae to survive winter conditions at the northern limits of the white-tailed deer (Odocoileus virginianus) range. Fecal pellets freshly deposited by infected deer were collected at the beginning of each winter month (9 December 1996 to 12 March 1997) and placed out in a traditional deer wintering area located near Grand Marais, Minnesota, and at a site in Thunder Bay, Ontario. The temperatures experienced by larvae at different levels within the snow cover were monitored and survivorship was calculated each month. Overall larval survivorship from December to April was only 27%. Although temperatures experienced by larvae beneath the snow for 4 months at Grand Marais were greatly moderated (-0.2 to -2.5°C) compared with air temperatures (6.5 to -24.0°C), fewer larvae survived (16%) than at a lower, constant temperature (-14oC) in the laboratory (76%). The mean numbers of first-stage larvae passed by deer (expressed per gramof dried feces (gd)) varied considerably over winter, from a low of 289/gd in December to a peak of 1127/gd in March. Considerable reproductive potential was lost because this spring (March) rise occurred before the end of winter. Nonetheless, the meningeal worm still successfully infects up to 82% of white-tailed deer in northern areas, and it is probably those larvae produced during the snow-free period while deer are dispersed over their summer habitat that play the biggest role in transmission.

Multi-Center Calibration of the Second Reference Material for Thromboplastin, Rabbit, Plain, Coded CRM 149R

1991 ◽  
Vol 65 (03) ◽  
pp. 263-267 ◽  
Author(s):  
A M H P van den Besselaar ◽  
R M Bertina
Keyword(s):  
Reference Material ◽  
Standard Error ◽  
Standard Errors ◽  
Sensitivity Index ◽  
Long Term Stability ◽  
Significant Bias ◽  
The Mean ◽  
The Relationship ◽  
International Sensitivity Index

SummaryIn a collaborative trial of eleven laboratories which was performed mainly within the framework of the European Community Bureau of Reference (BCR), a second reference material for thromboplastin, rabbit, plain, was calibrated against its predecessor RBT/79. This second reference material (coded CRM 149R) has a mean International Sensitivity Index (ISI) of 1.343 with a standard error of the mean of 0.035. The standard error of the ISI was determined by combination of the standard errors of the ISI of RBT/79 and the slope of the calibration line in this trial.The BCR reference material for thromboplastin, human, plain (coded BCT/099) was also included in this trial for assessment of the long-term stability of the relationship with RBT/79. The results indicated that this relationship has not changed over a period of 8 years. The interlaboratory variation of the slope of the relationship between CRM 149R and RBT/79 was significantly lower than the variation of the slope of the relationship between BCT/099 and RBT/79. In addition to the manual technique, a semi-automatic coagulometer according to Schnitger & Gross was used to determine prothrombin times with CRM 149R. The mean ISI of CRM 149R was not affected by replacement of the manual technique by this particular coagulometer.Two lyophilized plasmas were included in this trial. The mean slope of relationship between RBT/79 and CRM 149R based on the two lyophilized plasmas was the same as the corresponding slope based on fresh plasmas. Tlowever, the mean slope of relationship between RBT/79 and BCT/099 based on the two lyophilized plasmas was 4.9% higher than the mean slope based on fresh plasmas. Thus, the use of these lyophilized plasmas induced a small but significant bias in the slope of relationship between these thromboplastins of different species.

Colonialism and the Highland Clearances

2017 ◽  
Vol 8 (1) ◽  
pp. 22-48 ◽  
Author(s):  
Iain Mackinnon
Keyword(s):  
Industrial Development ◽  
Comparative Approach ◽  
Indigenous Research ◽  
Internal Colonialism ◽  
New Approach ◽  
A Site ◽  
Relationship Of ◽  
The Relationship ◽  
Imperial State ◽  
Late Modern

This article employs a new approach to studying internal colonialism in northern Scotland during the 18th and 19th centuries. A common approach to examining internal colonial situations within modern state territories is to compare characteristics of the internal colonial situation with attested attributes of external colonial relations. Although this article does not reject the comparative approach, it seeks to avoid criticisms that this approach can be misleading by demonstrating that promoters and managers of projects involving land use change, territorial dispossession and industrial development in the late modern Gàidhealtachd consistently conceived of their work as projects of colonization. It further argues that the new social, cultural and political structures these projects imposed on the area's indigenous population correspond to those found in other colonial situations, and that racist and racialist attitudes towards Gaels of the time are typical of those in colonial situations during the period. The article concludes that the late modern Gàidhealtachd has been a site of internal colonization where the relationship of domination between colonizer and colonized is complex, longstanding and occurring within the imperial state. In doing so it demonstrates that the history and present of the Gaels of Scotland belongs within the ambit of an emerging indigenous research paradigm.

Evaluation of the Efficacy of ST2 and NT-proBNP in the Diagnosis and Prediction of Short- Term Prognosis in Heart Failure with Reduced Ejection Fraction

2017 ◽  
Vol 9 (04) ◽  
Author(s):  
Shivananda B Nayak ◽  
Dharindra Sawh ◽  
Brandon Scott ◽  
Vestra Sears ◽  
Kareshma Seebalack ◽  
...  
Keyword(s):  
Heart Failure ◽  
Ejection Fraction ◽  
Cardiac Biomarkers ◽  
Double Blind Study ◽  
Short Term ◽  
Double Blind ◽  
Reduced Ejection Fraction ◽  
The Mean ◽  
Design And Methods ◽  
The Relationship

Purpose: i) To determine the relationship between the cardiac biomarkers ST2 and NT-proBNP with ejection fraction (EF) in heart failure (HF) patients. ii) Assess whether a superiority existed between the aforementioned cardiac markers in diagnosing the HF with reduced EF. iii) Determine the efficacy of both biomarkers in predicting a 30-day cardiovascular event and rehospitalization in patients with HF with reduced EF iv) To assess the influence of age, gender, BMI, anaemia and renal failure on the ST2 and NT-proBNP levels. Design and Methods: A prospective double-blind study was conducted to obtain data from a sample of 64 cardiology patients. A blood sample was collected to test for ST2 and NT-proBNP. An echocardiogram (to obtain EF value), electrocardiogram and questionnaire were also obtained. Results: Of the 64 patients enrolled, 59.4% of the population had an EF less than 40%. At the end of the 30- day period, 7 patients were warded, 37 were not warded, one died and 17 were non respondent. Both biomarkers were efficacious at diagnosing HF with a reduced EF. However, neither of them were efficacious in predicting 30-day rehospitalization. The mean NT-proBNP values being: not rehospitalized (2114.7486) and 30 day rehospitalization (1008.42860) and the mean ST2 values being: not rehospitalized (336.1975), and 30-day rehospitalization. (281.9657). Conclusion: Neither ST2 or NT-proBNP was efficacious in predicting the short- term prognosis in HF with reduced EF. Both however were successful at confirming the diagnosis of HF in HF patients with reduced EF.

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