scholarly journals Using a Silica Substrate to Monitor the Effectiveness of Radiocarbon Pretreatment

Radiocarbon ◽  
2011 ◽  
Vol 53 (4) ◽  
pp. 705-711 ◽  
Author(s):  
M W Dee ◽  
F Brock ◽  
A D Bowles ◽  
C Bronk Ramsey

The objective of radiocarbon pretreatment is to eliminate any contaminant carbon from the sample material. Solvent washes and acid-base-acid (ABA) procedures are widely used for this purpose. However, quantitatively analyzing their effectiveness is surprisingly problematic, as it often requires large numbers of 14C measurements or high-precision compositional analysis. The technique presented here involves monitoring the impact of different forms of contamination by measuring their adherence to a non-carbonaceous substrate called Chromosorb®. Firstly, the substrate was used in place of a 14C sample in order to monitor the accrual of carbon contamination during a standard solvent wash and ABA pretreatment. This produced a contamination profile against which modifications to the pretreatment procedure could be compared. Secondly, stocks were prepared of Chromosorb that had been infused with environmental contaminants and with common glues, adhesives, and preservatives. By monitoring the elimination of carbon from these stocks, the effectiveness of different pretreatment procedures could be evaluated and the most problematic of the contaminants for 14C dating could be identified.

2015 ◽  
Vol 12 (3) ◽  
pp. 181-192 ◽  
Author(s):  
Pinar Yazgan ◽  
Deniz Eroglu Utku ◽  
Ibrahim Sirkeci

With the growing insurrections in Syria in 2011, an exodus in large numbers have emerged. The turmoil and violence have caused mass migration to destinations both within the region and beyond. The current "refugee crisis" has escalated sharply and its impact is widening from neighbouring countries toward Europe. Today, the Syrian crisis is the major cause for an increase in displacement and the resultant dire humanitarian situation in the region. Since the conflict shows no signs of abating in the near future, there is a constant increase in the number of Syrians fleeing their homes. However, questions on the future impact of the Syrian crisis on the scope and scale of this human mobility are still to be answered. As the impact of the Syrian crisis on host countries increases, so does the demand for the analyses of the needs for development and protection in these countries. In this special issue, we aim to bring together a number of studies examining and discussing human mobility in relation to the Syrian crisis.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Brian J. Johnson ◽  
Amy Robbins ◽  
Narayan Gyawali ◽  
Oselyne Ong ◽  
Joanne Loader ◽  
...  

AbstractKoala populations in many areas of Australia have declined sharply in response to habitat loss, disease and the effects of climate change. Koalas may face further morbidity from endemic mosquito-borne viruses, but the impact of such viruses is currently unknown. Few seroprevalence studies in the wild exist and little is known of the determinants of exposure. Here, we exploited a large, spatially and temporally explicit koala survey to define the intensity of Ross River Virus (RRV) exposure in koalas residing in urban coastal environments in southeast Queensland, Australia. We demonstrate that RRV exposure in koalas is much higher (> 80%) than reported in other sero-surveys and that exposure is uniform across the urban coastal landscape. Uniformity in exposure is related to the presence of the major RRV mosquito vector, Culex annulirostris, and similarities in animal movement, tree use, and age-dependent increases in exposure risk. Elevated exposure ultimately appears to result from the confinement of remaining coastal koala habitat to the edges of permanent wetlands unsuitable for urban development and which produce large numbers of competent mosquito vectors. The results further illustrate that koalas and other RRV-susceptible vertebrates may serve as useful sentinels of human urban exposure in endemic areas.


2017 ◽  
Author(s):  
Horacio J Adrogué ◽  
Nicolaos E Madias

Respiratory acid-base disorders are those disturbances in acid-base equilibrium that are expressed by a primary change in CO2 tension (Pco2) and reflect primary changes in the body’s CO2 stores (i.e., carbonic acid). A primary increase in Pco2 (and a primary increase in the body’s CO2 stores) defines respiratory acidosis or primary hypercapnia and is characterized by acidification of the body fluids. By contrast, a primary decrease in Pco2 (and a primary decrease in the body’s CO2 stores) defines respiratory alkalosis or primary hypocapnia and is characterized by alkalinization of the body fluids. Primary changes in Pco2 elicit secondary physiologic changes in plasma [HCO3ˉ] that are directional and proportional to the primary changes and tend to minimize the impact on acidity. This review presents the pathophysiology, secondary physiologic response, causes, clinical manifestations, diagnosis, and therapeutic principles of respiratory acidosis and respiratory alkalosis.  This review contains 4 figures, 3 tables, and 59 references. Key words: Respiratory acidosis, respiratory alkalosis, primary hypercapnia, primary hypocapnia, hypoxemia, pseudorespiratory alkalosis


2009 ◽  
Vol 8 (1) ◽  
Author(s):  
Chris Roseveare ◽  

Milestones are often seen as opportunities for reflection and reminiscence. As this edition of the journal coincides with the 10th anniversary of my consultant appointment I hope readers will forgive a couple of paragraphs of self-indulgence. The phrase: ‘Where did all that time go?’ will probably be familiar to physicians at a more advanced stage of their career. With medical students now returning as specialist registrars, and former house officers appearing as consultant colleagues, the passage of time is increasingly apparent. I recently realised that our current third year students were born in the year I clerked my first patient: surprisingly I still remember his name, age and diagnosis, unlike many of those (and all of the students!) who I have seen since. On a more positive note, there have clearly been a lot of changes over these ten years: at the time of my appointment in June 1999 there was just a small handful of ‘acute physicians’ in the UK. SAM meetings attracted barely 100 delegates, despite providing free admission, and most of us had planned our escape route in case the acute medicine concept went ‘belly-up’ before our retirement. Now, with several hundred acute medicine consultants, similar numbers of trainees, and ‘full speciality’ status rapidly approaching, job security should no longer be a major concern. Indeed, the last 12 months has seen a further considerable expansion of the speciality; all of the first cohort of acute medicine trainees in Wessex have secured consultant positions, and I am told that SAM now has close to 700 full members. What the next ten years will bring remains to be seen, but with an ageing population and year-round pressures from rising emergency admissions, acute medicine will surely continue to strengthen. As I indicated last time, an increasing number of research-based submissions will be trickling into the journal over the next few editions. The impact of alcohol on the Health Service is a subject which has been at the top of the political agenda in recent months. So it is timely to include an article highlighting its impact on the Acute Medical intake in a busy Teaching hospital in this edition of the journal. The finding that one-in-five patients admitted to the AMU were considered ‘hazardous’ drinkers will probably come as no surprise to acute physicians working elsewhere in the UK. In fact this figure may have been an under-estimate given that the number of units consumer per week was not documented in 30% of clerking records. The demographic shift away from the stereotype ‘middle-aged male’ drinker is also apparent with large numbers of females aged 40-59 falling into this category. Recent editions of this journal would not seem complete without mention of training in practical procedures. In this issue the SAM trainee representatives have summarised the recent trainee survey in this area, providing some recommendations which will hopefully be incorporated into the new curriculum. Readers who are becoming tired of this subject can be reassured that this should be the final article relating to this for the time being! I hope this edition provides interesting reading and please keep the submissions coming – although the review articles are usually solicited by the editorial team, we will continue to consider any submitted article for publication, provided there is a clear teaching message for those working in the field of Acute Medicine. Any feedback on the articles included in this or previous editions would also be welcome, and may be included in a future ‘viewpoint’ or ‘letters to the editor’ section.


2018 ◽  
Vol 71 (1) ◽  
pp. 126-161
Author(s):  
Jonathan Bendor ◽  
Jacob N. Shapiro

AbstractHistorians and some scholars of international relations have long argued that historical contingencies play a critical role in the evolution of the international system, but have not explained whether they do so to a greater extent than in other domains or why such differences may exist. The authors address these lacunae by identifying stable differences between war and other policy domains that render the evolution of the international system more subject to chance events than those other domains. The selection environment of international politics has produced tightly integrated organizations (militaries) as the domain’s key players to a much greater degree than other policy domains. Because there are few players, no law of large numbers holds, and because militaries are tightly integrated, microshocks can reverberate up to macro-organizational levels. The anarchic character of the international system amplifies the impact of these shocks. The authors explore these phenomena in a range of historical examples.


1997 ◽  
Vol 1997 (1) ◽  
pp. 217-225
Author(s):  
Stephen J. Parr ◽  
Robert J. Haycock ◽  
Malcolm E. Smith

ABSTRACT Much of the Pembrokeshire coast and islands, together with its inshore waters, are of international importance for their breeding seabirds and wintering seaduck. Although the Sea Empress oil spill occurred before the breeding season, some 7000 oiled birds were recovered dead or alive. The impact of the oil spill on birds can be classified as follows: immediate mortality especially of more than 4500 wintering common scoter in Carmarthen Bay; sublethal effects on productivity of colonies and reduced adult survival from oil or dispersant ingestion; and chronic effects on bird populations from long-term pollution, particularly of prey. A range of monitoring and research projects are under way to investigate the impact, but it is premature to provide many results. The oil spill probably caused significant local declines in seabird colony sizes, especially of guillemot. The impact on common scoter will prove difficult to determine because of the poor quality and high variability of preincident data. Large numbers of oiled birds, particularly common scoter, were treated and subsequently released. The successful rehabilitation of such released birds is controversial; research and review results will be reported.


BMC Nutrition ◽  
2021 ◽  
Vol 7 (1) ◽  
Author(s):  
Dorothy Apondi Othoo ◽  
Sophie Ochola ◽  
Elizabeth Kuria ◽  
Judith Kimiywe

Abstract Background Iron deficiency anemia (IDA) remains high in Kenya despite interventions. Twenty-seven percent of children aged 6 months-14 years are anemic, with low iron intake (7%) among children aged 6–23 months. Standard food interventions involve a corn soy blend (CSB), which is limited in micronutrients, and fortifiers are not accessible locally. Moreover, the use of spirulina as a strategy for mitigating IDA has not been adequately documented. This study compared the impact of a spirulina corn soy blend (SCSB) on IDA among children aged 6–23 months. Methods A total of 240 children with IDA were randomly assigned to study groups at a ratio of 1:1:1 through lotteries, and caregivers and research assistants were blinded to group assignment. Dry-take-home SCSB, CSB and placebo flour (1.7 kg) was given to caregivers to prepare porridges using a flour water ratio of 1:4, producing 600 ml–700 ml of porridge to feed children 200 ml of porridge three times a day for 6 months. Impact was assessed as plasma hematocrit at baseline and after the study. Blood drawing, preparation and analysis were performed in accordance with approved procedures by the EthicsResearchCommittee. Monthly follow-up and data collection on dietary intake, anthropometry, morbidity and infant feeding practices were performed using questionnaires. Relative risk, magnitude of change and log-rank tests were used to compare the impact of the intervention, and significant differences were determined at P < 0.05. Results The survival probabilities for children consuming SCSB were significantly higher than those consuming CSB (log-rank-X2 = 0.978; CI: 0.954–1.033, P = 0.001) and the placebo (log-rankX2 = 0.971; CI: 0.943–0.984, P = 0.0001). Children consuming SCSB had a mean recovery time of 8 days (CI: 7–12 days) compared to those consuming CSB (19 days; CI: 20–23 days) and placebo (33 days; CI: 3 1–35 days). The recovery rate was 15.4 per 100 persons per day for children who consumed SCSB as opposed to 4.6 and 1.8 per 100 persons per day for those who consumed CSB and the placebo, respectively. Conclusion Management of IDA with SCSB compared to CSB and the placebo led to faster reversal and large numbers of recoveries from IDA. The recovery rates were above the World Health Organizations (WHO) minimums standards for food interventions. Efforts to realize high and faster recoveries from IDA should be heightened by fortifying CSB with spirulina powder.


2021 ◽  
Vol 9 ◽  
Author(s):  
Mohamed A. Daw

Background: Since the Arab uprising in 2011, Libya, Syria and Yemen have gone through major internal armed conflicts. This resulted in large numbers of deaths, injuries, and population displacements, with collapse of the healthcare systems. Furthermore, the situation was complicated by the emergence of COVID-19 as a global pandemic, which made the populations of these countries struggle under unusual conditions to deal with both the pandemic and the ongoing wars. This study aimed to determine the impact of the armed conflicts on the epidemiology of the novel coronavirus (SARS-CoV-2) within these war-torn countries and highlight the strategies needed to combat the spread of the pandemic and its consequences.Methods: Official and public data concerning the dynamics of the armed conflicts and the spread of SARS-COV-2 in Libya, Syria and Yemen were collected from all available sources, starting from the emergence of COVID-19 in each country until the end of December 2020. Datasets were analyzed by a set of statistical techniques and the weekly resolved data were used to probe the link between the intensity levels of the conflict and the prevalence of COVID-19.Results: The data indicated that there was an increase in the intensity of the violence at an early stage from March to August 2020, when it approximately doubled in the three countries, particularly in Libya. During that period, few cases of COVID-19 were reported, ranging from 5 to 53 cases/day. From September to December 2020, a significant decline in the intensity of the armed conflicts was accompanied by steep upsurges in the rate of COVID-19 cases, which reached up to 500 cases/day. The accumulative cases vary from one country to another during the armed conflict. The highest cumulative number of cases were reported in Libya, Syria and Yemen.Conclusions: Our analysis demonstrates that the armed conflict provided an opportunity for SARS-CoV-2 to spread. The early weeks of the pandemic coincided with the most intense period of the armed conflicts, and few cases were officially reported. This indicates undercounting and hidden spread during the early stage of the pandemic. The pandemic then spread dramatically as the armed conflict declined, reaching its greatest spread by December 2020. Full-blown transmission of the COVID-19 pandemic in these countries is expected. Therefore, urgent national and international strategies should be implemented to combat the pandemic and its consequences.


Sign in / Sign up

Export Citation Format

Share Document