Category Archives: Science

Consider Smell: Arctic Edition (Behind the Scenes Sneak Preview)

Join #considersmell this Friday in Fairbanks Alaska for an Arctic Edition of a travelling series of events that explore smelling, and other senses, through time and space. Come to the Ursa Major Distillery on Parks Highway from 5-8 for a multi-sensory experience!

prepartySome tools to get us started: the smoking gun! We use this to create foods from local trees (well, mostly!) Sadly, we can’t serve that yummy leek ash pasta on Friday!

a walk

the team

 

Our team takes a break! A walk in the woods to contemplate the light, the art, the science, and to smell things (we brought a pro along for help!).

 

a blue ballThe installation explores the synergy of art and science. Actively engage your senses and travel the interlocking sensual pathways that lead to perception. Explore molecular cocktails (we love the Arctic blueball mojito-see blue ball photo!), neurogastronomy, olfactory art, smell masks, a sound installation, 3D odor molecules, and photography enhanced with bespoke smells.The first thing installed is calm!

calm

read meThe exhibit is partially up! First goes the calm–that and the cocktail (thanks, Rob!) helped make the vinyl cuts even more fun to put up! A few photo nooks masked out and the rest up tomorrow!

 

Here’s a sneak peak of some things on offer–photographs with smells created, curated, and distilled!

earth-fall-k isovalericSmell fall in Fairbanks…

rural-super snow-j snow

 

Winter in Fairbanks…

urban-harringey-urban decay
Urbanity in Haringey…

urban-banksy-j urban decay

or the Banksy’s stone canvas at Turnpike Lane.

canal-urban-regents-rotting
Maybe sweet Chinese incense along Regent’s Canal after an afternoon on Primrose Hill.
water-whitstable-sea

Or the fresh air of Whitstable Seafront!

 

 

Smell Masks! They tell a story unique to an individual–a bespoke blend of smells crafted collaboratively. Come and smell the narrative of the Yukon Crossing and the Arctic Change.smell mask

Leave a comment

Filed under Alaska, Food, Olfaction, Science, Senses

Consider Smell: Arctic Edition

Kara C. Hoover and Julia Feuer-Cotter

4 March 2016. Anthropology Colloquium in Bunnell 405 from 3-4:30
Consider Smell: Smelling Imagined Geographies through Time and Space

4 March 2016. First Friday at Ursa Major Distillery from 5-8pm
Join us for a multi-sensory experience that opens the nose to engage deeply across the senses via multisensory molecular cocktails with locally produced spirits, neurogastronomical foods, and interactive art that imagines other geographies. Art pieces range from molecular rendering of olfactory signaling, photography enhanced with bespoke smells, interactive sculptures, crowd sourced smell maps, and smell masks which explore another person’s reality through the nose. This series of works explores the synergy of art and science via the sense of smell. Kara C Hoover uses the nose as an environmental probe to explore smelling across time and space. Julia Feuer-Cotter explores how this environmental perception is enacted in Alaska’s recent past through cultural practices along the Dalton Highway.

14-17 March Arctic Perspectives at the UAF Gallery
Visit “Exploring the past with the sense of smell: circumpolar narratives and the creation of place: at the art show “Arctic Perspectives” at the  Fine Arts Complex/UAF Art Gallery. An opening reception for the exhibit will be held on 14 March 2016 and all are welcome to attend.  Art will be on display 12–17 March during regular Gallery hours, 9am – 5pm. The Gallery is located in the Art Department wing of the Fine Arts Complex, Room 313. On the left side of the Great Hall, the Gallery is the first door to the left immediately upon entering the wing.

1 Comment

Filed under Alaska, Denisovan, Neandertal, Olfaction, Science, Senses

Sex and Evolution?

I like Michael Stoddart’s books in general–he has some great contributions to make and is one of a few popular scientists promoting olfaction. While reading his most recent book, I have been a bit frustrated by the simplistic view of human evolution and behavior. A recent Guardian piece by him “Smell evolution and the sex brain: Why we’re monogamous and use perfume” captures the source of my frustration. As a biological anthropologist, I find it hard to read the following sentence:

To keep male and female together to provide protection for babies, a suite of anatomical and physiological features evolved to promote the constant availability of sex throughout the year – irrespective of the monthly ovulation cycle.

The argument is that a suite of traits evolved (e.g., reduced sexual dimorphism, hidden estrus) to render human females receptive to sex at any time and this has led to monogamy–meanwhile male receptivity to sex is used as an explanation for purported male promiscuity. Huh! The constant male bias in science is at the heart of taxonomy–our class is called mammal because male scientists felt the key trait of mammals was the use of mammary glands to feed offspring.

Increasing the diversity of voices in academia has allowed us, slowly, to move away from teleological explanations for human behavior based on western society. In biological and evolutionary anthropology, human reproduction is a hot topic and more complicated. Stoddart does qualify his statement a bit:

Yet Homo Sapiens is the only species among the 5,500 kinds of mammal to maintain monogamous family relationships – or at least serially so – and to live in densely populated areas. This combination is extremely rare in nature.

Marriage, as an institution is barely thousands of years old (our species is 200,000 years old) and the concept of marrying for love younger still. Divorce is higher today partly because there are fewer economic and political structures keeping people together–religion is what is left and that doesn’t appear strong enough for most people–divorce was central in Henry the VIII’s split with the Pope. Most cultures are polygamous even if most end up practicing monogamy (mainly due to financial and/or political constraints–not enough money or power to gain more spouses). Perhaps the clearest statement we can make on pair-bonding is that humans can, and often do, come together in a pair-bond for a period of time with a goal of child rearing but this shared interest isn’t immediately linked to sexual monogamy–they are separate issues. The period of shared interest (if it occurs) enables the child to reach a point where the ‘village’ can take on some of the burden through formal and informal education. But, even western society regularly abandons its children–part of the year, I live next door to a youth shelter and drop-in center so I see it daily.

I suppose most humans are humanists–Jon Marks is a biological anthropologist who has written many books on the subject from an evolutionary perspective with a goal to distinguish us from all the other primates. I am not a humanist even if I do appreciate what we have accomplished as a species (there’s a lot to be ashamed of too…). I think there is an inherent fallacy in not recognizing that we are animals and that we cheat and lie and love and, yes, react to odors just as animals do. We may be enculturated to curb instincts but the instincts that we are enculturated to curb and how we do so vary cross-culturally. The goal to overcome our instincts with reason is a cultural one, not a biological or evolutionary one.

And, contrary to this blanket statement:

Today we have a global fragrance market equal to the GDP of a medium-sized country. But because our nose (unlike the VNO) ultimately sends all smells for rational analysis by the brain, we do not slavishly respond to sex smells in the way dogs or mice do. An alluring perfume may help a relationship, but no perfume comes with a guarantee!

odors are first processed in the areas of the emotional center of the brain where memories are also deal with–we react to odors before the frontal lobe (where reasoning attempts to modulate instinct) gets the data and formulates a response. Maybe we wear perfume because it smells good–it takes us to places we want to be or reminds of us of memories we love or smells like things we love to eat–maybe wearing perfume is about sensuality not mating. Why is so much academic work reductionist? But, perhaps that is why I am a biological anthropologist, rather than a biologist. Still, I take the point that we may not react to odors with the full behavioral response other animals might, but we react nonetheless. The closing statement of the piece is perhaps the strangest, and to an anthropologist, the most off-putting:

And so we can live in at least relative harmony with our fellows, benefitting from the long-term genetic and evolutionary advantages provided by monogamy, while participating socially in everything society has to offer.

There probably should be more biological anthropologists writing popular press books on human evolution and this gives me even more motivation to get my long overdue book Smell of Evolution out!

Leave a comment

Filed under anthropology, Anthropology and Evolution, Olfaction, primate social life, religion, Science, Senses, sex

The chirality of smell

Limonene_struttura

Limonene

As I prepare the first half of my Science of Smell online class, I am having fun looking for various examples of all things biomolecular, biochemical, and genetic related to olfaction. If I were a taste and flavour chemist or a molecular gastronomist, I’d probably be interested in somehow exploiting the chirality of biomolecules in food and drinks!

Chirality refers to the non-symmetrical nature of some molecules. Non-symmetrical molecules are like our right and left hands: they appear the same in reverse but you cannot superimpose the image of one over the other in the mirror nor can a left-handed glove fit a right hand. In the pharmaceutical industry, chirality is very important because the enantiomer of a biomolecule that produces a positive outcome (like reducing morning sickness using thalidomide or hyperactivity using Ritalin) may cause a harmful effect (birth defects) or no effect. The handedness is determined by the stereocenter of a molecular. Those with ‘right’ handed stereocenters are ‘R’ or + enantiomers and those with ‘left’ handed stereocenters are ‘S’ or – enantiomers (the S comes from sinister, Latin for left).

Our olfactory receptors are clever things: they can tell the difference between the right and left hands! The two most common examples are of carvone and limonene.  The R-carvone/(-) carvone is recognized as mint and its enantiomer as carraway. R-limonene/(+) limonene smells ‘orange’ and its enantiomer is lemon (see image to the right). So next time you smell oranges and lemons at the same time, recognize the power of your nose to be ambidextrous by distinguishing between the two biomolecules!

Leave a comment

Filed under Food, Olfaction, Science, Senses, smell of the week

Smelling in the polar vortex

Since so many parts of the US (mainly the Great Plains, mid-west, and parts of the northeast) are experiencing normal interior Alaska winter temperatures right now, I thought I’d write about what/if we smell when it gets cold.

Our ability to smell things is related to temperature because temperature is a key factor in volatility (tendency to vaporize). We tend to smell volatile compounds (those with high vapor pressure at normal temperatures) that have molecular weights below 300 daltons. Volatiles with lower molecular mass tend to have lower boiling points and evaporate and diffuse more rapidly than compounds with high molecular masses. For example, ethanol (pure alcohol) has a mass of 46 daltons and will vaporize and diffuse at a lower temperature and more rapidly than indole (a fecal smelling element often added to jasmine perfumes to produce a musky scent) which has a mass of 117 daltons.

2009

Ice fog in Fairbanks

Boiling is one end of the vaporization extreme and freezing is the other. The freezing point of water is 0 but other molecules have lower thresholds–however, even if a molecule isn’t frozen, the colder it is, the less thermal energy it will have and its volatility will be reduced (think  of how the aroma of cooled food is not as strong when it was hot). When temperatures are extremely cold, the sense of smell is de facto eliminated (even if your nose weren’t blocked by anti-frostbite protective gear like balaclavas). During the winter in Fairbanks, the only things you can reliably smell outside (down to a certain temperature) are wood burning stoves and car exhaust pollution–both in heavy concentrations trapped close to the ground due to temperature inversion. Maybe another reason we like hot bevvies during cold weather is the welcome rush of volatiles!

Leave a comment

Filed under Alaska, Science, Senses

Clandestine trysts and human evolution

Recent advances in the field of paleogenomics (the study of ancient genomes) have uncovered the story of inter-species mating in those early days out of Africa before dispersal into Eurasia. Prior to these studies we’ve had little evidence supporting either cultural interaction with archaic humans or inter-breeding.

Clandestine trysts or common practice? The draft sequence of the Neanderthal genome published in 2010 revealed that we mated with Neanderthals in the Near East enough to share 1-4% of our DNA with them. On the heels of the draft sequence of the Neandertal genome, the same team published the Denisovan genome using DNA extracted from an exceptionally preserved finger bone from remains found in Denisova Cave in Siberia. The archaeological data at Denisova show a mixed toolkit with elements of Upper- and Middle-Paleolithic industries. Molar morphology indicated Denisovans were distinct from both modern and known archaic humans. The genomic data indicate Denisovans were indeed a new species with unique genomic markers. The power of modern genomics allows us to also find evidence of mating with modern humans, specifically modern Melanesians who share 4-6% of their genomes with Denisovans. Were these matings clandestine trysts or was there more at stake—some flow of genes to modern humans that helped us adapt to the novel environments of Europe and Asia?

Genomic breadcrumbs? Preliminary comparisons between Neandertal and human genes indicate significant differences in aspects of cognition, metabolism, and skeletal and skin morphology. But what about the inherited portion of the genome? Does it have a role in any functional aspect of our biology and physiology? Dr. Green, lead author on the draft sequence of the Neandertal genome described the inherited portion as ‘sparsely distributed across the genome, just a ‘bread crumbs’ clue of what happened in the past’. But two new papers tell a different story, suggesting that inter-breeding may have significantly contributed to successful adaptation to the new environments of Eurasia.

In the summer of 2011, another team identified a Neandertal origin for a unique cluster of co-inherited gene variants (a haplotype) in the non-coding segment of the dystrophin gene on the X-chromosome. This haplotype occurs at a frequency of 9% in all modern non-African human populations and likely first appeared in the genome prior to or very early in the migration out of Africa. The authors of the study posit that either this genetic (and/or cultural) exchange enabled successful modern human adaptations to the novel environments of Eurasia. There is an intriguing possibility that human males left Africa in greater numbers and mated with archaic females: an earlier study on modern human variation found the X-chromosome experienced more than expected genetic drift at the time of human migration out of Africa, a pattern not found in the migrations into East Asia and Europe.The authors of this study conclude that female effective population size was reduced compared to males due to some sex-biased process or natural selection affecting the X-chromosome in non-African populations.

Speculations that inherited genomic material conferred a fitness advantage gained further ground in a study published this summer in Nature. A Stanford University team identified HLA gene variants that are rare in modern Africans but significantly present in West Asians, again suggesting genetic admixture outside Africa prior to Eurasian expansion. HLA class I genes are critical to the immune system because they target and destroy pathogens. The authors of the study argue that inter-breeding restored HLA diversity that was reduced by a population bottleneck in migration out of Africa, citing examples of similar events in the evolutionary genetic history of the peopling of the Americas. Not only was diversity restored to modern humans but new immune variants specifically adapted to local pathogens may have been acquired in the process as well. HLA-A*11 (associated with Epstein-Barr virus protection), for example, has become a dominant form in non-African populations occurring at rates of 64% in East Asia and Oceania (and even more in Papua New Guinea) suggesting strong selection. The high frequency of these gene variants (as compared with other regions of the genome) may be explained by the need for the immune system to be flexible to new pathogens (particularly rapidly evolving viruses), rendering it more susceptible to the forces of natural selection.

The future of the past. If the data from these various studies is supported by future work, we may end up rethinking our relationship to our closest cousins – were we separate species? Even field biologists who have the array of genes, biology, physiology and behavior sometimes have trouble determining whether two groups be classed as separate species or not. For those working in paleoanthropology or paleogenomics, the dataset is even more limited and the creation of new taxa is temporary pending further data but useful as a heuristic tool.

The field of paleogenomics is relatively young and has a tremendous number of methodological and technical challenges to overcome before we can comfortably say that the sequences yielded are authentic and reliably represent the genetic data. A major challenge is verifying and authenticating the endogenous (or local) DNA in a specimen that has been potentially contaminated by microbes and human researchers. The past decade has been punctuated by marvelous advances that have helped us better understand recent human evolution and ourselves. The possibility that our advantage in global colonization derives from early acts of inter-breeding is a fascinating one. With the rapid advancements in technology and increased interest in ancient DNA, the future looks promising for unraveling the story of the immediate past.

  1. Green, R. E. et al., Science 328, 710 (2010).
  2. Reich, D. et al., Nature 468, 1053 (2010).

2 Comments

Filed under anthropology, Anthropology and Evolution, Denisovan, Neandertal, race, Science, sex

Data, Central Tendency, and Normalcy

In exploring some old data recently to see if it was publishable, I began to contemplate the things we take for granted in scientific studies. Statistics are so commonly used today that any paper is expected to have a smattering of tests and the all important p-values. (The incorrect use of alpha as inter-changeable with p-value is an irksome issue but one that has been explored by others as is the issue of the value of the p-value!) Canned programs like Systat, SPSS, and even SAS or Minitab enable quick data analysis, which has revolutionized many fields of study. As the scientific community continues to grow and the pressure to get grants and publish increases, we should be more concerned the level of statistical knowledge our peers and students have. Knowledge of the software is not knowledge of statistical theory. I would hazard an argument that the latter is more important than the former.

Take for instance, the issue of sample size. In some fields, small sample sizes are all that is available–paleontologists for example–what you find is what you have. Yet, sample size directly impacts the power of the statistical test at hand. So, given a small sample size, a post hoc power analysis is a valuable self-assessment as to whether your conclusions are warranted.

Data distribution is another issue. Without a normal distribution (or a tendency toward it, at the very least), one cannot accurately estimate population parameters. While non-parametric statistical analysis has developed tremendously throughout the years, it is often viewed as a weak version of the more powerful multi-variate analysis. How many people take the time to test whether their data are normally distributed before they run their factor analysis, discriminant function, time regression, and so on?

Every single statistical test has a tremendous number of assumptions and rules. Those who consume studies that have statistical analyses assume (perhaps incorrectly) that each study is properly vetted by reviewers and editors to ensure the study has met these assumptions that the test is the most appropriate? But, we don’t know. Quite simply, we rely on three things. We trust that our colleagues adhere to professional ethical standards. In cases of honest error, we trust that the peer review process flags them for correction before publication. If the other two fail, we trust that studies seeking to replicate the original will be a final failsafe. Unless the topic is a hot one though that ultimate failsafe may never happen or take so long the original unwarranted conclusion takes root and becomes entrenched.

What do we do before results are replicated? Think critically. Treat everything that is published as if one is the peer reviewer. Any gaps in reporting or unanswered questions should raise flags that perhaps the study at hand may not be the best one to cite in one’s own paper without some discussion of the problems.

Thinking critically requires extra time, precious extra time. But, I think it produces a better, stronger community that fosters greater attention to detail and better results overall. I would like to see more of it, as opposed to the sloppy lit reviews, hurried and often trite uncritical discussion of methods, discriminating presentation of results that disguise true problems with the study, and overblown conclusions.

Leave a comment

Filed under Analysis, critical thinking, Research, Science, Statistics