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NewsPsychology (Sep. 27, 2012) — The deserts of Utah and Nevada have not always been dry. Between 14,000 and 20,000 years ago, when large ice caps covered Canada during the last glacial cooling, valleys throughout the desert southwest filled with water to become large lakes, scientists have long surmised. At their maximum size, the desert lakes covered about a quarter of both Nevada and Utah. Now a team led by a Texas A&M University researcher has found a new water cycle connection between the U.S. southwest and the tropics, and understanding the processes that have brought precipitation to the western U.S. will help scientists better understand how the water cycle might be perturbed in the future.

Mitch Lyle, professor of oceanography, led the study with colleagues from Columbia University, University of California-Santa Cruz, Stanford University, Hokkaido University of Japan, Brown University and the U.S. Geological Survey. Their work, funded by the National Science Foundation, is published in the current issue of Science magazine.

The dry shorelines of these glacial lakes were first discovered by 19th century geologists when the west was first explored, Lyle explains, adding that the source of the additional water has been a mystery. By assembling data from ocean sediments and from dry western valleys collected over the last 30 years, Lyle and the team found a new water cycle connection between the southwest U.S. and the tropics.

“Large ice caps profoundly altered where storms went during glacial periods. Before this study, it was assumed that Pacific winter storms that now track into Washington and Canada were pushed south into central and southern California,” Lyle notes.

“However, by comparing timing between wet intervals on the coast, where these storms would first strike, with growth of the inland lakes, we found that they didn’t match.”

The team was able to time wet periods along the California coast from pollen buried in marine sediments from cores archived by scientists at the Integrated Ocean Drilling Program at Texas A&M. They evaluated lake level studies from southeast Oregon, Nevada, Utah, eastern California, New Mexico, and west Texas to find when lakes filled in different parts of the west.

“Many teams of scientists have been working on this problem since the 1950s, when radiocarbon dating first allowed ages to be put on old shorelines,” Lyle adds. “The data we synthesized covers a wide latitude so that we could determine how the glacial wet intervals operated.”

Only southern California coastal wet intervals matched with the progression of high lakes inland, pointing to the development of a tropical connection, where storms cycled into the region from the tropical Pacific, west of southern Mexico.

“We think that the extra precipitation may have come in summer, enhancing the now weak summer monsoon in the desert southwest. But we need more information about what season the storms arrived to strengthen this speculation,” Lyle says.

Not only is the development of the glacial lakes important from a paleoclimate perspective, but it is likely that the lakes were important to the migration of people into North America, Lyle believes. Many of the archaeological sites where early Indians settled when they first came into the U.S. are rock shelters at the edges of these ancient lakes. The lakes were a major source of fish, and a gathering place for deer and wildfowl at that time.

“What we need to do now is look at all of this on a finer scale,” Lyle points out. “We need to understand better the processes that directed the storms thousands of years ago, and to predict better what changes might occur in the future.”

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Story Source:

The above story is reprinted from materials provided by Texas A&M University, via EurekAlert!, a service of AAAS.

Note: Materials may be edited for content and length. For further information, please contact the source cited above.

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Journal Reference:

1. Mitchell Lyle, Linda Heusser, Christina Ravelo, Masanobu Yamamoto, John Barron, Noah S. Diffenbaugh, Timothy Herbert, Dyke Andreasen. Out of the Tropics: The Pacific, Great Basin Lakes, and Late Pleistocene Water Cycle in the Western United States. Science, 28 September 2012: Vol. 337 no. 6102 pp. 1629-1633 DOI: 10.1126/science.1218390

NewsPsychology (Sep. 28, 2012) — Many white sharks shift from fish to marine mammals as they mature, but individual sharks show surprising variability in dietary preferences.

White sharks, the largest predatory sharks in the ocean, are thought of as apex predators that feed primarily on seals and sea lions. But a new study by researchers at the University of California, Santa Cruz, shows surprising variability in the dietary preferences of individual sharks.

The researchers described their findings in a paper published online September 28 in PLoS ONE. They analyzed the composition of growth bands in shark vertebrae to trace variations in diet over a shark’s lifetime. Stable isotopes of carbon and nitrogen incorporated into an animal’s tissues serve as a natural tracer of dietary inputs.

“We did find that white shark diets changed with age, as expected, but we were surprised that the patterns and extent of change differed among individuals,” said Sora Kim, who led the study as a UCSC graduate student and is now at the University of Wyoming.

The researchers analyzed vertebrae of 15 adult white sharks that had been caught along the west coast (14 off California and one off Baja California). Sharks in this population consume a wide range of prey, including seals, sea lions, dolphins, fish, and squid. But not every shark eats the same mix of prey, said coauthor Paul Koch, professor of Earth and planetary sciences at UCSC.

“We confirmed that the diets of many individuals observed at seal and sea lion rookeries shift from fish to marine mammals as the sharks mature,” he said. “In addition, we discovered that different individual sharks may specialize on different types of prey. These two types of flexibility in feeding behavior are difficult to document using traditional methods, but may be very important for understanding how the population is supported by the eastern Pacific ecosystem and how it may respond to changes in that ecosystem.”

The National Oceanic and Atmospheric Administration (NOAA) recently announced that it will consider whether to protect the west coast population of white sharks under the Endangered Species Act.

Tagging studies have shown that the white sharks found along the California coast have a regular migratory pattern, cruising coastal sites from late summer to early winter and moving to offshore areas during the rest of the year. While sharks within this population may have predictable movement patterns, the new study shows that there are important dietary and behavioral differences among individual sharks.

The study relied on vertebrae obtained from white shark specimens in various collections. The sharks had been caught at different times and places along the coast from 1957 to 2000. “Interestingly, we do see a small shift in diet as marine mammal populations increased after the passage of the Marine Mammal Protection Act in 1972,” Kim said.

In addition to Kim and Koch, the coauthors of the paper include James Estes, professor of ecology and evolutionary biology at UCSC, and Tim Tinker, a biologist with the U.S. Geological Survey and adjunct professor of ecology and evolutionary biology at UCSC. This research was funded by the National Science Foundation.

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Story Source:

The above story is reprinted from materials provided by University of California – Santa Cruz. The original article was written by Tim Stephens.

Note: Materials may be edited for content and length. For further information, please contact the source cited above.

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Journal Reference:

1. Kim SL, Tinker MT, Estes JA, Koch PL. Ontogenetic and Among-Individual Variation in Foraging Strategies of Northeast Pacific White Sharks Based on Stable Isotope Analysis. PLoS ONE, 2012 DOI: 10.1371/journal.pone.0045068

NewsPsychology (Oct. 1, 2012) — Two thirds of drinking water in Germany is obtained from groundwater. At the same time groundwater is in no way a lifeless resource with at least 2,000 known species and numerous microorganisms mainly helping to clean the groundwater and improve the quality of drinking water. However, the protection of this habitat has not yet been established in law. The Institute for Environmental Sciences of the University of Koblenz-Landau has now presented a draft for the geographical classification of groundwater fauna, which could be used as an important step for the evaluation of the environmental status of groundwater. Its aim is the long-overdue establishment of suitable measures for the sustainable, ecologically-oriented management of groundwater.

European groundwater is bustling with at least 2,000 highly adapted, often very rare species such as turbellaria, rotifiers, water mites, fresh water amphipods and olms. Groundwater therefore provides one of the largest continental and oldest habitats in Europe. The so-called ecosystem services provided by groundwater creatures are highly relevant: the species-rich bacteria and fauna clean the water in the subsoil by decomposing organic material which has fallen from the surface to the bottom.

The creatures are also particularly suitable as bioindicators: due to their specialisation to the habitat, they are particularly susceptible to changes such as infiltration of surface water, fertilisers and pollutants such as metals and temperature fluctuations.

Compared to chemical analysis methods, they can provide a much earlier indication of changes in the water and in so doing make a significant contribution towards ensuring the quality of groundwater and therefore drinking water.

With the publication of the essay “Stygoregions — a promising approach to a bioregional classification of groundwater systems,” the research team led by associate lecturer Dr. Hans Jürgen Hahn of the Institute for Environmental Sciences of the University of Koblenz-Landau together with Dr. Christian Griebler of the Institute of Groundwater Ecology of the Helmholtz Centre, Munich, has developed a proposal for the biogeographical classification of groundwater habitats in Germany. For this publication, data from the project “Development of biological evaluation methods and criteria for groundwater ecosystems” commissioned by the Federal Environment Agency (UBA) and the LAWA (the German Working Group on water issues of the Federal States and the Federal Government represented by the Federal Environment Ministry) as well as numerous other studies by the University of Koblenz-Landau was evaluated. This is the first ever proposal for a definition of ecological references for groundwater over a wide area. These may provide an important basis for defining whether the environmental status of groundwater is good.

“Binding criteria and limits for the evaluation and sustainable protection of groundwater ecosystems can only be established on such a basis,” stresses Hahn. These already existed for surface water, however studies by the University of Koblenz-Landau have shown that this classification does not hold up for groundwater.

The scientists proposed a groundwater-specific classification with four potential so-called stygoregions for groundwater, taking Germany as an example. “Sustainable groundwater management is only possible if the groundwater ecology is taken fully into consideration,” explains Hahn. “Fortunately those responsible for water management and water supply are open minded about this issue, because they too know that only healthy groundwater ecosystems provide clean groundwater.”

Ultimately it is the politicians who are challenged to define the legal status of groundwater ecosytems. Although there are passages in laws such as the EU Groundwater Directive and the German Water Management Act in which groundwater is defined as waters and waterways and is therefore subject to the general principles of waterway management with all of its consequences and protective laws, to date there is no legal opinion or relevant precedent which would clarify the inconsistent legal situation and provide momentum to its implementation.

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Story Source:

The above story is reprinted from materials provided by Universität Koblenz-Landau, via AlphaGalileo.

Note: Materials may be edited for content and length. For further information, please contact the source cited above.

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Journal Reference:

1. Heide Stein, Christian Griebler, Sven Berkhoff, Dirk Matzke, Andreas Fuchs, Hans Jürgen Hahn. Stygoregions – a promising approach to a bioregional classification of groundwater systems. Scientific Reports, 2012; 2 DOI: 10.1038/srep00673

NewsPsychology (Oct. 1, 2012) — Carbon dioxide is not the only problem we must address if we are to understand and solve the problem of climate change. According to research published this month in the International Journal of Global Warming, we as yet do not understand adequately the role played by aerosols, clouds and their interaction and must take related processes into account before considering any large-scale geo-engineering.

There are 10 to the power of 40 molecules of the greenhouse gas carbon dioxide in the atmosphere. Those carbon dioxide molecules absorb and emit radiation mainly in the infrared region of the electromagnetic spectrum and their presence is what helps keep our planet at the relatively balmy temperatures we enjoy today.

Too few absorbing molecules and the greenhouse effect wanes and we would experience the kind of global cooling that would convert the whole planet into a lifeless, ice-encrusted rock floating in its orbit. Conversely, however, rising levels of atmospheric carbon dioxide lead to a rise in temperature. It is this issue that has given rise to the problem of anthropogenic climate change. Humanity has burned increasing amounts of fossil fuels since the dawn of the industrial revolution, releasing the locked in carbon stores from those ancient into the atmosphere boosting the number of carbon dioxide molecules in the atmosphere.

However, these rising carbon dioxide levels do not complete the picture of climate change, scientists must also take into account tiny particles in the atmosphere, aerosols, made up of condensing vapours, soot, and dust. There is certainly no doubt that these species affect how much solar energy is reflected from Earth’s surface and how much is trapped. According to Jost Heintzenberg of the Leibniz-Institute for Tropospheric Research, in Leipzig, Germany, the number of aerosol particles is a mere 10 to the 26. Of course, the weight we lend to a single carbon dioxide molecule compared to an aerosol particle, which might contain many more than a single molecule is a moot point.

Nevertheless, Heintzenberg sees a conundrum in how to understand atmospheric aerosols and how they affect cloud formation and ultimately influence climate. There are multiple feedback loops to consider as well as the effect of climate forcing due to rising carbon dioxide levels on these species and vice versa. “The key role of aerosols and clouds in anthropogenic climate change make the high uncertainties related to them even more painful,” says Heintzenberg. It is crucial that we understand their effects. Geo-engineers are considering projects on an enormous scale that might one day be used to manipulate levels of atmospheric aerosols and influence cloud formation in order to cool our planet. Such efforts while seeming fanciful today might eventually allow us to influence, if not take control of, the climate to some extent. If the models fail us in terms of aerosols and clouds then such manipulations might cause more problems than they fix.

“Before considering such remedies the aerosol-cloud-climate conundrum needs to be reduced to a level of uncertainty that is comparable to those related to anthropogenic greenhouse gases,” explains Heintzenberg. “Considering the complexity of the aerosol-cloud system the challenge will be to identify the necessary essential knowledge and differentiate that from marginal details and focus research efforts on these essentials in order to simplify the complex aerosol-cloud system without losing indispensable features,” he says.

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The above story is reprinted from materials provided by Inderscience, via AlphaGalileo.

Note: Materials may be edited for content and length. For further information, please contact the source cited above.

NewsPsychology (Oct. 1, 2012) — University of Leeds-led research has used tree rings from eight cedar trees in Bolivia to unlock a 100-year history of rainfall across the Amazon basin, that contains the world’s largest river system.

The new study shows that the rings in lowland tropical cedar trees provide a natural archive of data closely related to historic rainfall.

Researchers measured the amounts of two different oxygen isotopes trapped in the wood’s rings: oxygen-16 and the heavier oxygen-18. By looking at the varying amounts of the two isotopes, they could see how the pattern of rainfall changed year by year. This allowed them to see how much it rained over the Amazon basin over the past century.

The lead author of the study, Dr Roel Brienen from the School of Geography at the University of Leeds, said: “We already knew that some tropical tree species form annual rings and we also anticipated that the isotopic signature in these rings might record changes in the climate.

“What surprised us, however, is that just eight trees from one single site actually tell us how much it rained not just at that site but over the entire Amazon catchment. That is an area about 25 times the size of the UK. The isotope values recorded in tree rings were very closely related to annual variation in the river levels of the Amazon, and thus of the amount of rainfall that flows into the ocean.”

The Amazon basin is among the richest natural ecosystems in the world, containing about one tenth of the planet’s biodiversity and one fifth of the carbon stored in plant biomass. It is also among the wettest places in the world; about one fifth of the global land precipitation falls in the Amazon basin and drains into the Atlantic Ocean through the world’s biggest river.

Because of its vast size and location along the equator, the response of the hydrological cycle of the Amazon basin to climate change may significantly affect the magnitude and speed of climate change for the entire globe. It is therefore important to gain a better understanding of its hydrological cycle.

Co-author Dr Manuel Gloor, also at the University of Leeds, said: “Climate models vary widely in their predictions for the Amazon, and we still do not know whether the Amazon will become wetter or dryer in a warmer world. We discovered a very powerful tool to look back into the past, which allows us to better understand the magnitude of natural variability of the system.”

“In a similar way that annual layers in polar ice sheets have been used to study past temperatures, we are now able to use tree rings of this species as a natural archive for precipitation over the Amazon basin. If we find older trees with similar signal strength then this will greatly help us to advance our knowledge of the system.”

Dr Brienen added: “The record is so sensitive that simply from the isotope values we can say which year we are looking at. For example, the extreme El Niño year of 1925-26 which caused very low river levels, clearly stands out in the record.”

Although the century-long record provided by the trees is relatively short, some interesting trends are evident.

“The oxygen isotope series shows an increase over time, which may be due to an intensification of the hydrological cycle,” said Dr Gloor. “That could also explain the observed long-term trend in river discharge. We need however to replicate this research at different places in the Amazon to really be able to say more.”

The research is a collaboration between the University of Leeds, the Helmholtz Centre Potsdam (Germany), University of Utrecht and the Institut de Recherche pour le Developpement (IRD, Peru). Funders for the project included the UK Natural Environment Research Council (NERC) and the US-based Gordon and Betty Moore Foundation.

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Story Source:

The above story is reprinted from materials provided by University of Leeds.

Note: Materials may be edited for content and length. For further information, please contact the source cited above.

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Journal Reference:

1. RJW Brienen et al. Oxygen isotopes in tree rings are a good proxy for Amazon precipitation and El Niño-Southern Oscillation variability. Proceedings of National Academy of Sciences, 2012 DOI: 10.1073/pnas.1205977109

NewsPsychology (Oct. 1, 2012) — With a combination of microscopic laser scissors and modern sequencing methods, biologists at the Ruhr-Universität have analyzed the activity of genes in the entire genome of certain fungi in one fell swoop. Especially with organisms in the millimetre size range, it is a particular challenge because little cell material is available. The scientists of the RUB Department of General and Molecular Botany took advantage of the method to investigate the development of small multicellular fungi. The results are reported in the journal BMC Genomics.

Gene activity differs from tissue to tissue

In multicellular organisms, each cell contains the same genetic material, however, often only a fraction of the genes are active (expressed). These differences in gene expression are the cause of variations in the structure and physiology of cells. Gene expression is therefore the key to understanding the development of multicellular organisms. “In large organisms such as plants, it is usually not a problem to get enough starting material to study gene expression,” explains Dr. Minou Nowrousian. “In the case of microorganisms, organs often consist of only a few cells, and might be embedded in other tissues from which they are difficult to separate.” Therefore, biologists of the research groups of Prof. Dr. Ulrich Kück and Minou Nowrousian combined laser microdissection with modern sequencing technologies to analyze the gene activity during the development of certain just 0.5 millimetres large sexual structures of fungi.

How laser microdissection works

In laser microdissection, scientists cut defined regions of a sample under the light microscope with a laser beam. With this laser mini-scissors, the RUB researchers collected the fruiting bodies, i.e. the sexual structures of the fungus Sordaria macrospora, which has been used for decades as a model organism in developmental biology. From the fruiting bodies, they isolated the RNA which represents the gene activity. With the help of “next generation” sequencing, they characterized the activity of all genes of the genome simultaneously.

A transcription factor controls genetic activity in young fruiting bodies

The Bochum researchers compared the wild-type fungus with a mutant form that has no mature fruiting bodies, in other words is not able to reproduce sexually. For this purpose, they studied gene expression in young, immature fruiting bodies. They showed that some fruiting body-specific genes are not activated in the mutant. The defective gene contains the “building instructions” for a so-called transcription factor — a protein that turns other genes on or off. The RUB team also found that the fruiting body has a completely different genetic activity pattern to non-reproductive tissue. “With the new combination of methods, we want to investigate the activity of genes in other mutants and developmental stages to better understand the molecular mechanisms of multicellular development in fungi,” said Prof. Kück.

Fungi: ecological and economic importance

Fungi have a big impact on virtually all ecosystems. They make significant contributions to the reduction of animal and vegetable waste products and thereby contribute to the global carbon cycle. Some species live in symbiosis with plants or animals, other species are pathogens. In the chemical and pharmaceutical industry, fungi are used for the production of antibiotics and enzymes. The formation of pathogenic or symbiotic interactions and the production of medicines or biotechnology-related substances are often tied to specific stages in the life cycle of a fungus. The analysis of the development is therefore crucial not only for basic research but also for industrial applications.

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Story Source:

The above story is reprinted from materials provided by Ruhr-Universitaet-Bochum.

Note: Materials may be edited for content and length. For further information, please contact the source cited above.

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Journal Reference:

1. Ines Teichert, Gabriele Wolff, Ulrich Kück, Minou Nowrousian. Combining laser microdissection and RNA-seq to chart the transcriptional landscape of fungal development. BMC Genomics, 2012; 13 (1): 511 DOI: 10.1186/1471-2164-13-511

NewsPsychology (Oct. 1, 2012) — Researchers from the University of Alicante (Spain) have analysed ten brands of cigarettes and found that the concentrations of certain harmful and carcinogenic substances vary significantly from one brand to another. Until now legislation has not covered these compounds and only establishes limits for nicotine, tar and carbon monoxide. Scientists have also developed catalysts to reduce the harmful products in tobacco.

In accordance with current legislation, cigarette packets indicate the nicotine, tar and carbon monoxide concentrations in order to confirm that these do not exceed permitted levels. However the quantity of these substances is not always proportional to the toxicity levels of many other compounds¸ “therefore more suitable parameters are required for determining the toxicity level of tobacco.”

This is a conclusion of a study by chemical engineers at the University of Alicante (Spain), published in the journal Food and Chemical Toxicology. The researchers analysed the gases and particulate matter — tar — from ten commercial brands of blond tobacco cigarettes: three Spanish brands (Fortuna, Ducados and Nobel), and seven American or British brands (Marlboro, Winston, Chesterfield, Camel, L&M, Lucky Strike and John Player).

“Although the products generated appear similar, the relative performance (mg/cigarette) of certain highly toxic and carcinogenic compounds varies considerably from one brand to another,” highlights María Isabel Beltrán, one of the authors.

According to the study, the proportion of compounds detected in the gases is maintained in each packet type, but there are some that do not follow this tendency, such as isoprene, chrotonaldehyde and toluene, which are among the most carcinogenic and harmful ones.

The situation is similar in the case of particulate matter. The individual performance of these compounds is correlated with the global performance for each brand, but certain harmful substances, such as hydroquinone and cotinine do not adjust to this pattern and appear more in some brands than in others.

The results also reveal that the brands with the lowest production of gaseous compounds are not those with the lowest tar levels, and that the brand that generates the most isoprene, toluene and chrotonaldehyde produces a lower quantity of tar than the average. “We should not therefore assume that a cigarette which generates more tars is going to be more toxic than another that produces fewer,” notes Beltrán.

The researchers, who claim in the article not to have any conflict of interests, have preferred not to reveal the figures for each brand and have identified these with the letters A to J. To perform the analysis the cigarettes were inhaled in a ‘smoking machine’ and the smoke composition was measured in three fractions: one gaseous, in which 35 compounds were identified, and two of particulate matter, with 85 compounds, which were trapped respectively in the filter and in the smoke traps used to measure “what a person smokes.”

It has, therefore, been observed that in the cigarettes containing more tobacco, the amount consumed in a set number of puffs is lower. According to the scientists, this is because there is less oxygen available due to the increased packing.

With respect to the regulated substances, when compared to other studies, it was found that the level of carbon monoxide in Spanish cigarettes is ‘medium-high’ with respect to the others, and one of the brands (‘C’) even slightly exceeded the value established by law (10 mg/cigarette), containing 11.1 mg/cigarette.

“The results must be considered with caution and compared to those from other laboratories as, although we experimented with 200 cigarettes, sometimes the data may vary depending on the batch of packets or the environmental conditions,” stated the researcher, “and in any case, we do not think we should be the ones to report them.”

The performance of nicotine in the traps varies from 0.28 to 0.61 mg/cigarette, that is, the amount may double from one brand to another, while remaining within legal limits. “In fact, although nicotine is responsible for the addiction, it is not the most harmful part of the cigarette,” says Beltrán. “Of the more than three thousand compounds in tobacco there are many which are worse, such as hydrogen cyanide, 1,3-butadiene or some of the families of aldehydes, nitrosamines and phenols.”

To reduce the quantities of toxic products in the cigarettes, the researchers have also tested and developed several catalysers. One of these, known as Al-MCM-41, reduces carbon monoxide emissions by 23% and nicotine emissions by more than 40%.

“The three-dimensional structure of this material, clay with silicon and aluminium oxides, permits the formation of ‘caves’ in which the long chain compounds are retained,” says Beltrán, who confirmed that the flavour of the tobacco is hardly affected and that some of the leading companies have already expressed interest in the patent for the new catalyser.

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Story Source:

The above story is reprinted from materials provided by Plataforma SINC, via AlphaGalileo.

Note: Materials may be edited for content and length. For further information, please contact the source cited above.

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Journal References:

1. A. Marcilla, I. Martínez, D. Berenguer, A. Gómez-Siurana, M.I. Beltrán. Comparative study of the main characteristics and composition of the mainstream smoke of ten cigarette brands sold in Spain. Food and Chemical Toxicology, 2012; 50 (5): 1317 DOI: 10.1016/j.fct.2012.01.046
2. A. Marcilla, A. Gómez-Siurana, D. Berenguer, I. Martínez-Castellanos, M.I. Beltrán. Reduction of tobacco smoke components yields by zeolites and synthesized Al-MCM-41. Microporous and Mesoporous Materials, 2012; 161: 14 DOI: 10.1016/j.micromeso.2012.05.010