An Appraisal of Cloud Seeding as a Means of Increasing Precipitation

1951 ◽  
Vol 32 (2) ◽  
pp. 39-46 ◽  
Author(s):  
Henry G. Houghton
Keyword(s):  
Large Scale ◽  
Scale Effects ◽  
Cloud Physics ◽  
Cloud Seeding ◽  
Activation Temperature ◽  
Synoptic Meteorology ◽  
Ice Nuclei ◽  
Pertinent Information ◽  
Vertical Development ◽  
Increasing Precipitation

The results of cloud-seeding experiments are reviewed briefly and it is concluded that, taken alone, they do not constitute an adequate basis for a sound appraisal of the potentialities of the cloud seeding techniques. An attempt is made to extend and supplement the observational evidence with the aid of existing knowledge of cloud physics and synoptic meteorology. It is found that significant amounts of precipitation can fall only from clouds which are continuously replenished. It is concluded that the thermal effects of seeding are seldom sufficient to stimulate the vertical development of a cloud. Since the activation-temperatures of the artificial ice-nuclei are believed to be higher than the activation-temperatures of natural ice-nuclei there is a possibility that seeding may advance the onset of precipitation or release precipitation from clouds which do not extend to the activation-temperature of the natural ice-nuclei. It appears that the seeding of clouds which are already releasing precipitation may either decrease or increase the total precipitation; an unequivocal answer is not possible due to the lack of pertinent information regarding natural precipitation processes. On the basis of the analysis of the physical processes and general knowledge of synoptic meteorology it is concluded that it is unlikely that cloud seeding will cause large-scale effects. Further research on cloud physics and cloud seeding is recommended.

scholarly journals A non-targeted LC–MS metabolic profiling of pregnancy: longitudinal evidence from healthy and pre-eclamptic pregnancies

Metabolomics ◽  
2021 ◽  
Vol 17 (2) ◽  
Author(s):  
Tiina Jääskeläinen ◽  
◽  
Olli Kärkkäinen ◽  
Jenna Jokkala ◽  
Anton Klåvus ◽  
...  
Keyword(s):  
Large Scale ◽  
Scale Effects ◽  
Late Pregnancy ◽  
Metabolite Profile ◽  
Adverse Outcomes ◽  
Liquid Chromatography Mass Spectrometry ◽  
Targeted Metabolomics ◽  
Serum Samples ◽  
Healthy Women ◽  
Maternal Metabolism

Abstract Introduction Maternal metabolism changes substantially during pregnancy. However, few studies have used metabolomics technologies to characterize changes across gestation. Objectives and methods We applied liquid chromatography–mass spectrometry (LC–MS) based non-targeted metabolomics to determine whether the metabolic profile of serum differs throughout the pregnancy between pre-eclamptic and healthy women in the FINNPEC (Finnish Genetics of Preeclampsia Consortium) Study. Serum samples were available from early and late pregnancy. Results Progression of pregnancy had large-scale effects to the serum metabolite profile. Altogether 50 identified metabolites increased and 49 metabolites decreased when samples of early pregnancy were compared to samples of late pregnancy. The metabolic signatures of pregnancy were largely shared in pre-eclamptic and healthy women, only urea, monoacylglyceride 18:1 and glycerophosphocholine were identified to be increased in the pre-eclamptic women when compared to healthy controls. Conclusions Our study highlights the need of large-scale longitudinal metabolomic studies in non-complicated pregnancies before more detailed understanding of metabolism in adverse outcomes could be provided. Our findings are one of the first steps for a broader metabolic understanding of the physiological changes caused by pregnancy per se.

scholarly journals Glucose-Limited Fed-Batch Cultivation Strategy to Mimic Large-Scale Effects in Escherichia coli Linked to Accumulation of Non-Canonical Branched-Chain Amino Acids by Combination of Pyruvate Pulses and Dissolved Oxygen Limitation

2021 ◽  
Vol 9 (6) ◽  
pp. 1110
Author(s):  
Ángel Córcoles García ◽  
Peter Hauptmann ◽  
Peter Neubauer
Keyword(s):  
Amino Acids ◽  
Dissolved Oxygen ◽  
Large Scale ◽  
Scale Effects ◽  
Branched Chain Amino Acids ◽  
Oxygen Limitation ◽  
Fed Batch ◽  
Fermentation Products ◽  
Cultivation Strategy ◽  
Branched Chain

Insufficient mixing in large-scale bioreactors provokes gradient zones of substrate, dissolved oxygen (DO), pH, and other parameters. E. coli responds to a high glucose, low oxygen feeding zone with the accumulation of mixed acid fermentation products, especially formate, but also with the synthesis of non-canonical amino acids, such as norvaline, norleucine and β-methylnorleucine. These amino acids can be mis-incorporated into recombinant products, which causes a problem for pharmaceutical production whose solution is not trivial. While these effects can also be observed in scale down bioreactor systems, these are challenging to operate. Especially the high-throughput screening of clone libraries is not easy, as fed-batch cultivations would need to be controlled via repeated glucose pulses with simultaneous oxygen limitation, as has been demonstrated in well controlled robotic systems. Here we show that not only glucose pulses in combination with oxygen limitation can provoke the synthesis of these non-canonical branched-chain amino acids (ncBCAA), but also that pyruvate pulses produce the same effect. Therefore, we combined the enzyme-based glucose delivery method Enbase® in a PALL24 mini-bioreactor system and combined repeated pyruvate pulses with simultaneous reduction of the aeration rate. These cultivation conditions produced an increase in the non-canonical branched chain amino acids norvaline and norleucine in both the intracellular soluble protein and inclusion body fractions with mini-proinsulin as an example product, and this effect was verified in a 15 L stirred tank bioreactor (STR). To our opinion this cultivation strategy is easy to apply for the screening of strain libraries under standard laboratory conditions if no complex robotic and well controlled parallel cultivation devices are available.

Grabbing Life by the Ballot: Creating an Effective Ballot through Design

2020 ◽  
Author(s):  
Katharine McCoy
Keyword(s):  
Product Design ◽  
Design Process ◽  
Large Scale ◽  
Scale Effects ◽  
The World ◽  
Ballot Design ◽  
The Government ◽  
Democratic Elections ◽  
Effective Design ◽  
Undergraduate Thesis

This presentation, reflecting a politics undergraduate thesis, will explore the design process behind the ballots that voters use in democratic elections around the world. Ballots are an inherently political objects, and in many cases, the most direct line of communication a citizen has to the government of their country. As such, the design of the ballot affects the legitimacy of higher level electoral and democratic institutions. This project argues that by co-opting the language of product design, a universal ballot design process would make more efficient ballots across the globe.   Product design starts with a brainstorming stage that explores at the user, the goal of the object, and the context of its use to create an effective design. By applying these observations to the process of designing a ballot, each electoral commission can produce a more effective ballot. Currently there is no standardization for ballot design other than ensuring that electoral commissions tried to make it “friendly.” By examining cases of bad ballot design, it is possible to see what element of the design process was missed or misused to create a process that corrects for these mistakes. This project examines poorly designed ballots in Florida, Scotland, and Colombia to explore the large-scale effects these small design choices make, and how to fix them. 

scholarly journals 3D mapping of host-parasite-microbiome interactions reveals metabolic determinants of tissue tropism and disease tolerance in Chagas disease

2019 ◽  
Author(s):  
Ekram Hossain ◽  
Sharmily Khanam ◽  
Chaoyi Wu ◽  
Sharon Lostracco-Johnson ◽  
Diane Thomas ◽  
...  
Keyword(s):  
Chagas Disease ◽  
Large Intestine ◽  
Large Scale ◽  
Scale Effects ◽  
Parasitic Infection ◽  
Parasite Burden ◽  
Acute Stage ◽  
Disease Tolerance ◽  
Chronic Stage ◽  
Spatially Resolved

AbstractChagas disease (CD) is a parasitic infection caused by Trypanosoma cruzi protozoa. Over 8 million people worldwide are T. cruzi-positive, 20-30% of which will develop cardiomyopathy, megaoesophagus and/or megacolon. The mechanisms leading to gastrointestinal (GI) symptom development are however poorly understood. To address this issue, we systematically characterized the spatial impact of experimental T. cruzi infection on the microbiome and metabolome across the GI tract. The largest microbiota perturbations were observed in the proximal large intestine in both acute and chronic disease, with chronic-stage effects also observed in the cecum. Strikingly, metabolomic impact of acute-to-chronic stage transition differed depending on the organ, with persistent large-scale effects of infection primarily in the oesophagus and large intestine, providing a potential mechanism for GI pathology tropism in CD. Infection particularly affected acylcarnitine and lipid metabolism. Building on these observations, treatment of infected mice with carnitine-supplemented drinking water prevented acute-stage mortality with no changes in parasite burden. Overall, these results identified a new mechanism of disease tolerance in CD, with potential for the development of new therapeutic regimens. More broadly, these results highlight the potential of spatially-resolved metabolomic approaches to provide insight into disease pathogenesis, with translational applications for infectious disease drug development.

Ergodic Capacity and Symbol Error Rate Analysis of a Wireless System with α-μ Composite Fading Channel

2021 ◽  
Author(s):  
Fereshteh salimian rizi ◽  
Abolfazl Falahati
Keyword(s):  
Error Rate ◽  
Fading Channel ◽  
Communication Systems ◽  
Large Scale ◽  
Scale Effects ◽  
Ergodic Capacity ◽  
Symbol Error Rate ◽  
Performance Criteria ◽  
Rate Analysis ◽  
New Generation

Abstract A composite α-µ/Lognormal fading channel is proposed with several channel performance criteria. This model considers the most effective occurrences in a fading channel, mainly non-linearity, multi-cluster nature of propagation medium, and shadowing effects. The new generation of communication systems is moving towards the use of millimetre waves (mmW). In this type of propagation, large-scale effects of fading channel on the received signal are significant, so in the proposed composite model, the lognormal distribution is considered to model large-scale effects of fading, which is the most accurate distribution to model shadowing. The Gaussian-Hermite quadrature sum is used to approximate the probability distribution function (PDF) of the proposed model. After calculating the statistics, the symbol error rate (SER) and ergodic capacity are computed. The Mellin transform technique is used to calculate the SER expression of different modulation schemes; then, ergodic capacity is computed for a diverse frequency spectrum. Finally, the Monte Carlo method is used to evaluate the analyses.

Benthic Habitats and the Effects of Fishing

2005 ◽  
Keyword(s):  
Fisheries Management ◽  
Large Scale ◽  
Scale Effects ◽  
Ecosystem Processes ◽  
Fishing Effort ◽  
Habitat Types ◽  
Benthic Habitats ◽  
Management Actions ◽  
Ecosystem Effects ◽  
Ecosystem Based Fisheries Management

<strong><em>Abstract. </em></strong>We review the impacts of towed gears on benthic habitats and communities and predict the consequences of these impacts for ecosystem processes. Our emphasis is on the additive and synergistic large-scale effects of fishing, and we assess how changes in the distribution of fishing activity following management action are likely to affect production, turnover time, and nutrient fluxes in ecosystems. Analyses of the large-scale effects of fishing disturbance show that the initial effects of fishing on a habitat have greater ecosystem consequences than repeated fishing in fished areas. As a result, patchy fishing effort distributions have lower total impacts on the ecosystem than random or uniform effort distributions. In most fisheries, the distribution of annual fishing effort within habitats is more patchy than random, and patterns of effort are maintained from year to year. Our analyses suggest that many vulnerable species and habitats have only persisted in heavily fished ecosystems because effort is patchy. Ecosystem-based fisheries management involves taking account of the ecosystem effects of fishing when setting management objectives. One step that can be taken toward ecosystem-based fisheries management is to make an a priori assessment of the ecosystem effects of proposed management actions such as catch controls, effort controls, and technical measures. We suggest a process for predicting the ecosystem consequences of management action. This requires information on habitat distributions, models to predict changes in the spatial distribution of fleets following management action, and models of the impacts of trawling disturbance on ecosystem processes. For each proposed management action, the change in disturbance affecting different habitat types would be predicted and used to forecast the consequences for the ecosystem. These simulations would be used to produce a decision table, quantifying the consequences of alternative management actions. Actions that minimize the ecosystem effects of fishing could then be identified. In data-poor situations, we suggest that management strategies that maintain or maximize the patchiness of effort within habitat types are more consistent with the precautionary approach than those that lead to more uniform fishing effort distributions.

scholarly journals Charged Particle (Negative Ion)-Based Cloud Seeding and Rain Enhancement Trial Design and Implementation

Water ◽  
2020 ◽  
Vol 12 (6) ◽  
pp. 1644
Author(s):  
Wei Zheng ◽  
Fengming Xue ◽  
Ming Zhang ◽  
Qiqi Wu ◽  
Zhou Yang ◽  
...  
Keyword(s):  
Large Scale ◽  
Evaluation Method ◽  
Water Shortage ◽  
Northwest China ◽  
Negative Ion ◽  
Cloud Seeding ◽  
Weather Modification ◽  
Solid Carbon Dioxide ◽  
Design And Implementation ◽  
Hygroscopic Salts

China has been suffering from water shortage for a long time. Weather modification and rainfall enhancement via cloud seeding has been proved to be effective to alleviate the problem. Current cloud seeding methods mostly rely on solid carbon dioxide and chemicals such as silver iodide and hygroscopic salts, which may have negative impacts on the environment and are expensive to operate. Lab experiments have proved the efficiency of ion-based cloud seeding compared with traditional methods. Moreover, it is also more environmentally friendly and more economical to operate at a large scale. Thus, it is necessary to carry out a field experiment to further investigate the characteristics and feasibility of the method. This paper provides the design and implementation of the ion-based cloud seeding and rain enhancement trial currently running in Northwest China. It introduces the basic principle of the trial and the devices developed for it, as well as the installation of the bases and the evaluation method design for the trial.

The Campaign Against Windstorms in the Banana Plantations Near Santa Marta, Colombia, 1956–57

1961 ◽  
Vol 42 (4) ◽  
pp. 265-276 ◽  
Author(s):  
Manuel E. López ◽  
Wallace E. Howell
Keyword(s):  
Sierra Nevada ◽  
Large Scale ◽  
Cloud Seeding ◽  
Trade Winds ◽  
Severe Storms ◽  
Easterly Waves ◽  
Banana Plantations ◽  
Local Cloud ◽  
Great Damage ◽  
Stimulation Of

Windstorms do great damage in banana plantations near the Sierra Nevada de Santa Marta in Colombia. These plantations, which owe their location to the rainfall maximum caused by convergence in the trade winds as they flow around the mountain massif, suffer most damage from the few most violent tempests and relatively little from the frequent milder squalls, offering the prospect that even slight mitigation of severe storms would be economically rewarding. Most damage was found to be triggered by easterly waves and similar large-scale disturbances, though the windstorms themselves remained purely local. Cloud seeding to attempt reduction of windstorm intensity was undertaken during the 1956 and 1957 seasons on the hypothesis that stimulation of showers early in the diurnal build-up of instability would dissipate some of the instability and reduce insolation at the ground, thus diminishing the intensity of later convective overturning. Comparison of damages during these seeded seasons with those of preceding and subsequent seasons showed a marked reduction in the ratio of severe windstorms to mild ones during the campaign and a reduction perhaps as much 39 per cent in damages, worth several million dollars annually.

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