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Ten new insights in climate science 2020 – a horizon scan
- Erik Pihl, Eva Alfredsson, Magnus Bengtsson, Kathryn J. Bowen, Vanesa Cástan Broto, Kuei Tien Chou, Helen Cleugh, Kristie Ebi, Clea M. Edwards, Eleanor Fisher, Pierre Friedlingstein, Alex Godoy-Faúndez, Mukesh Gupta, Alexandra R. Harrington, Katie Hayes, Bronwyn M. Hayward, Sophie R. Hebden, Thomas Hickmann, Gustaf Hugelius, Tatiana Ilyina, Robert B. Jackson, Trevor F. Keenan, Ria A. Lambino, Sebastian Leuzinger, Mikael Malmaeus, Robert I. McDonald, Celia McMichael, Clark A. Miller, Matteo Muratori, Nidhi Nagabhatla, Harini Nagendra, Cristian Passarello, Josep Penuelas, Julia Pongratz, Johan Rockström, Patricia Romero-Lankao, Joyashree Roy, Adam A. Scaife, Peter Schlosser, Edward Schuur, Michelle Scobie, Steven C. Sherwood, Giles B. Sioen, Jakob Skovgaard, Edgardo A. Sobenes Obregon, Sebastian Sonntag, Joachim H. Spangenberg, Otto Spijkers, Leena Srivastava, Detlef B. Stammer, Pedro H. C. Torres, Merritt R. Turetsky, Anna M. Ukkola, Detlef P. van Vuuren, Christina Voigt, Chadia Wannous, Mark D. Zelinka
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- Journal:
- Global Sustainability / Volume 4 / 2021
- Published online by Cambridge University Press:
- 27 January 2021, e5
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Non-technical summary
We summarize some of the past year's most important findings within climate change-related research. New research has improved our understanding of Earth's sensitivity to carbon dioxide, finds that permafrost thaw could release more carbon emissions than expected and that the uptake of carbon in tropical ecosystems is weakening. Adverse impacts on human society include increasing water shortages and impacts on mental health. Options for solutions emerge from rethinking economic models, rights-based litigation, strengthened governance systems and a new social contract. The disruption caused by COVID-19 could be seized as an opportunity for positive change, directing economic stimulus towards sustainable investments.
Technical summaryA synthesis is made of ten fields within climate science where there have been significant advances since mid-2019, through an expert elicitation process with broad disciplinary scope. Findings include: (1) a better understanding of equilibrium climate sensitivity; (2) abrupt thaw as an accelerator of carbon release from permafrost; (3) changes to global and regional land carbon sinks; (4) impacts of climate change on water crises, including equity perspectives; (5) adverse effects on mental health from climate change; (6) immediate effects on climate of the COVID-19 pandemic and requirements for recovery packages to deliver on the Paris Agreement; (7) suggested long-term changes to governance and a social contract to address climate change, learning from the current pandemic, (8) updated positive cost–benefit ratio and new perspectives on the potential for green growth in the short- and long-term perspective; (9) urban electrification as a strategy to move towards low-carbon energy systems and (10) rights-based litigation as an increasingly important method to address climate change, with recent clarifications on the legal standing and representation of future generations.
Social media summaryStronger permafrost thaw, COVID-19 effects and growing mental health impacts among highlights of latest climate science.
Further studies of incubation at 44° C. as a test for ‘faecal coli’
- H. P. Sherwood, L. F. L. Clegg
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- Journal:
- Journal of Hygiene / Volume 42 / Issue 1 / January 1942
- Published online by Cambridge University Press:
- 15 May 2009, pp. 45-54
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1. The authors concluded in a previous paper that the most reliable single test for the detection of Bact. coli was incubation in MacConkey's broth at 44° C, such a test for Bact. coli alone being necessary in shellfish because of occasional multiplication of other coliforms in purified mussels. The present investigation is an attempt to verify this finding on a broader basis.
2. A description is given of the isolation of 1600 cultures of coliform organisms from polluted mussels, sewage, and faeces (human, cow, sheep and sea birds). Their classification according to ‘IMViC’ reactions and the production of gas in MacConkey's broth at temperatures of 37, 41, 44, 45 and 46° C. is given.
3. Of the + + − − type, 1036 out of 1065 cultures (97·3%) were found to produce gas in MacConkey's broth at 44° C. A balance is noted between the + + − − type which does not produce gas at 44° C. (irregular I) and the two irregular types which do so (irregular II and irregular VI). Such a balance was reported by Bardsley (1938).
4. From the cultures examined it is confirmed that incubation at 44° C. is the most suitable temperature for use with MacConkey's broth for permitting the maximum number of Bact. coli to produce gas while inhibiting the maximum number of other coliforms.
The bacteriological examination of molluscan shellfish
- L. F. L. Clegg, H. P. Sherwood
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- Journal:
- Journal of Hygiene / Volume 45 / Issue 4 / December 1947
- Published online by Cambridge University Press:
- 15 May 2009, pp. 504-521
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Section I
A standard bacteriological test for molluscan shellfish should fulfil certain requirements stated: briefly, the test should show the degree of pollution, be accurate and rapid, and self-sufficient, not requiring subsequent confirmation. Review of the subject leads to recommendations, first, to overcome the technical difficulties of preparing samples for testing; secondly, on the nature of the test. In preparation: external shell sterilization can usually be omitted, shell water should be discarded and replaced by sterile water to make a total volume three times that of the body tissues. Pooling of individual shellfish into one sample is acceptable in routine examinations. In the test: a solid medium is preferable to a liquid medium, giving more accurate results, and review of existing tests leads to the conclusion that the use of roll tubes of MacConkey agar incubated at 44° should meet the requirements of a standard test.
Section II
A modification was found necessary in the MacConkey agar: a mixture of 2 % gelatin and 5 % agar is used instead of the normal 2 % agar. Mechanical rolling devices for tubes are described and figured.
Among other critical experiments, 1000 roll-tube colonies grown at 44° from shellfish included 969 with + + − − ‘IMViC’ reactions and 979 acid and gas producers at 44°. The coefficient of variation among replicate tests of samples of shellfish and water in roll tubes was not seriously greater than that for colony counts in Petri dishes at 37° with ordinary MacConkey agar.
Colonies in roll tubes incubated at 44° can be counted as conveniently and accurately as those on Petri dishes, and, in general it is concluded that the new method is more satisfactory for estimation of faecal coli than other methods at present in use.
Section III
Directions are given for the preparation of shellfish and inoculation into roll cultures, both for individual and for pooled examination, and the method of determining results is described.
The interpretation of results is discussed, and it is suggested that shellfish which in four out of five samples from the same source are free from faecal coli in 1 ml. quantities of body tissue should be regarded as satisfactory for food. The presence of more than two or three faecal coli per ml. of body tissue in any one sample calls for appropriate action according to the number present.
Repeated re-use of sea water as a medium for the functioning and self-cleansing of molluscan shellfish
- L. A. Allen, G. Thomas, M. C. C. Thomas, A. B. Wheatland, H. N. Thomas, E. E. Jones, J. Hudson, H. P. Sherwood
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- Journal:
- Journal of Hygiene / Volume 48 / Issue 4 / December 1950
- Published online by Cambridge University Press:
- 15 May 2009, pp. 431-457
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When mussels are allowed to function in sea water the main changes occurring in the water are depletion of dissolved oxygen and lowering of pH value. Provided the faeces and pseudo-faeces are not disturbed the increase in the content of organic matter is not appreciable. If the supernatant water is removed and aerated with diffused air the water is re-oxygenated, the pH value is restored to its original level, and the water so treated may be re-used for immersing a fresh batch of mussels. The process of re-use may apparently be continued indefinitely.
Under these conditions a high degree of cleansing is achieved by the mussels, the count of coli-aerogenes bacteria being reduced to a small fraction of the original; counts of bacteria in the water, on the other hand, are subject to large fluctuations. It was considered advisable for this reason to chlorinate the water between each cycle of cleansing in order to immerse the mussels on each occasion in water which itself was reasonably certain to be free from coliform bacteria, potentially including pathogens.
Experience showed that the greatest difficulty involved in the use of chlorine was in removing residual chlorine so that it would not inhibit functioning of the mussels when the water was re-used. After trials of various alternatives it was concluded that the most satisfactory method was to determine by means of small-scale tests the smallest quantity of chlorine (below the break-point) required to give a residual concentration of 0·05–0·10 p.p.m. in the re-used water and then to add the corresponding quantity with precision to the bulk of water by means of a dosing apparatus while the water was being pumped from the mussel tank to the aeration tank. After a period of contact of 1 hr. the water was aerated for a further hour. A series of trials in a semll-scale plant showed that this treatment ensured that residual chlorine in the water being added to the mussels did not exceed 0·05 p.p.m.; as a result the mussels functioned satisfactorily and the degree of cleansing attained was comparable with that attained in the existing mussel-cleansing tanks in which sterilized fresh sea water is used for each cycle of cleansing. Although the concentration of residual chlorine was small the mussels kept the water so clear that this concentration was effectively bactericidal and the bacterial quality of the water was usually comparable with that of good drinking water. Low temperatures retard the metabolic activity of mussels and below 4° C. this is so marked that the degree of cleansing achieved is unsatisfactory. For this reason it is recommended that the temperature of the re-used water should be maintained at 6° C. (43° F.) or above.
Oysters were found to be satisfactorily cleansed by a process of re-use similar to that adopted for mussels, provided the temperature of the water was maintained at 54° F. (12·2° C.) or rather higher.
Small-scale trials showed that artificial sea water, prepared by dissolving in fresh water suitable quantities of the major constituents of natural sea water, could be successfully re-used for cleansing mussels.
Incubation at 44°C. as a test for faecal coli
- L. F. L. Clegg, H. P. Sherwood, R. W. Dodgson
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- Journal:
- Journal of Hygiene / Volume 39 / Issue 4 / July 1939
- Published online by Cambridge University Press:
- 15 May 2009, pp. 361-374
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1. The use of Esch. coli alone as an index of faecal pollution for shellfish, and the correlation between the 44° C. MacConkey test and citrate tests are discussed.
2. The mercury-toluene thermo-regulator used in these experiments, which gives a maximum variation of ± 0.1° C., is discussed briefly and illustrated.
3. Experiments are described in which 522 colonies from polluted shellfish were isolated, inoculated into MacConkey's broth and incubated at temperatures of 37° C. and at successive 1° intervals from 41 to 46° C., in accurately controlled water-baths. An almost perfect negative correlation was found to exist between 44° C. incubation and the citrate test.
4. It appeared that temperatures above 44° C. are detrimental to the growth of Esch. coli.
5. Certain cultures of citrate-negative lactose fermenters at 37° C., which were inhibited at 44° C., were found on further investigation to be mostly intermediate types.
A Millimetre/Submillimetre Study of Optically Selected Quasars
- W. A. Sherwood, G. V. Schultz, E. Kreysa, H.-P. Gemünd
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- Journal:
- Symposium - International Astronomical Union / Volume 97 / 1982
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- 14 August 2015, pp. 305-306
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- 1982
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During the past decade many kinds of optical surveys have discovered hundreds of quasars most of which (∼90 %) are radio quiet (<10 mJy at 5 GHz). We have observed two samples of quasars brighter than 17m.6 found by their emission lines and by their ultraviolet excess. We have also selected quasars with redshifts known to be greater than 3.00. A brief description of the observing technique is given by Sherwood et al. (1981b). We have compared our millimetre photometry of flat radio spectrum quasars with that of Ennis and Werner and find excellent agreement. For four of the 8 sources in common the data have been published: Kreysa et al. (1980) and Jones et al. (1981). In addition, analysis of our “noise” shows it to be white, gaussian distributed about zero. The three samples are summarized as follows.