Twitter Redesigns Profiles, Adds Engagement Features

Twitter has rolled out a new design for users’ profile pages. The important changes are:

  • Graphics are emphasized, with much larger header images
  • Tweets that are getting more “engagement” are in a larger font. The algorithm used to measure a tweet’s engagement is not revealed by Twitter. Engagement appears to be based on the number of retweets, mentions, favorites, and clicks. Apparently large-font tweets only happen on desktop Twitter, not on mobile.
  • You can choose a tweet that you want to emphasize, to be “pinned” to the top of your profile.

More information from Twitter on the new profile:
Coming soon: a whole new you, in your Twitter profile

To see further commentary, search for appropriate terms in Google and Twitter. For instance:

To keep up with what’s happening at Univ Iowa and with Twitter, follow @HardinLib and @EricRumsey.

 

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PubMed Food Problem – Olive Oil

By Eric Rumsey and Janna Lawrence

[Check out additional articles on PubMed & Plant-Based Foods]

Olive oil as a healthy food is a highly popular topic among consumers. It’s also popular among researchers, as shown in a list of the 100 most popular research articles of 2013, by the Altmetric site, in which the number two ranking article is a comparison of olive oil and nuts for prevention of cardiovascular disease, in NEJM. This article shows a major problem with the MeSH indexing of olive oil. Even with its trending popularity, olive oil does not have its own MeSH term. In the NEJM article, and in most articles on olive oil, the only MeSH term that corresponds with olive oil is Plant Oils. This is a problem because Plant Oils is not in any food-diet-nutrition (FDN) explosion, and is therefore not retrieved by broad searches for FDN.

Fortunately, articles on olive oil are often picked up by broad FDN searches because they have other FDN-related MeSH terms. But in many cases, they are not. Here are some examples of articles with olive oil in the title that are not retrieved using our broad FDN hedge because they contain no MeSH terms or text words relating to food, diet or nutrition:

As we’ve discussed previously, most plant-based foods are difficult to search in PubMed because the MeSH terms for them are in the Plants explosion and not in any FDN explosion. Notably, olive oil has a different problem. It’s like other plant-based foods in not having a MeSH term that’s in an FDN explosion. But instead of being in Plants, its MeSH term, Plant Oils, is in the Chemicals and Drugs explosion.

There’s another baffling quirk in the MeSH indexing of olive oil. Although it doesn’t have its own MeSH term, there are MeSH terms for several other dietary oils in the Dietary Fats explosion (which, of course, is retrieved in broad FDN searches). These other dietary fats are Cod Liver Oil, Corn Oil, Cottonseed Oil, Safflower Oil, Sesame Oil, and Soybean Oil. None of these has close to the number of citations as there are on olive oil. We searched for each of these oils as a phrase in the title, and compared this with olive oil, and found, remarkably, that the total of all of these other oils combined is about the same as the number for olive oil by itself. So why is there not a MeSH term for olive oil?!

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PubMed Food Problem: Cranberry & Cranberries

By Eric Rumsey and Janna Lawrence

[Check out additional articles on PubMed & Plant-Based Foods]

Part of the problem in searching for food in PubMed is that it’s often the case that there’s a fuzzy border between between food and medicine.   A food that is enjoyed for its taste and general nutritional benefits may have properties that make it therapeutic for specific health conditions. A good example of this is cranberries, and cranberry juice, which may have benefits for prevention of urinary tract infections.

As with most plant-based foods, in MeSH indexing, cranberry is in the Plants explosion, and it’s not in any food, diet or nutrition (FDN) explosion. Fortunately, most articles on cranberries and cranberry juice are assigned some FDN indexing terms so that they are retrieved in broad FDN searches. Articles on cranberry juice are often under Beverages, and some articles on cranberries are under Fruit or Dietary supplements.

To show how this works in PubMed, we searched for cranberry or cranberries in the article title, limited to human, and retrieved 322 articles. We then combined this with our broad hedge search to get all articles that contain food, diet or nutrition MeSH terms or text words. This retrieved 255 articles — 79% of the cranberry/cranberries articles, which is a fairly good retrieval. But still, it’s certainly notable that there are 67 articles that are not retrieved, many of which appear to be very much on target, that don’t contain any FDN MeSH terms or text words. Here are some examples:

As we mentioned above, plant-based foods are tricky to search in PubMed because the name of the food plant is usually only in Plants, and not in any FDN explosion. The five articles above are all indexed under Vaccinium macrocarpon, the taxonomic name of cranberry, which is in the Plants explosion. So if you were searching for articles on urinary tract infections and plant-based foods, a strategy that would retrieve these articles would be to combine Urinary Tract Infections AND Plants.

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Is Chocolate A Food? A Problem In PubMed

By Eric Rumsey and Janna Lawrence

[Check out additional articles on PubMed & Plant-Based Foods]

As we’ve written, searching for food-related subjects in PubMed is difficult because of the way the MeSH system is organized. Plant-based foods are especially difficult because in most cases they are treated mainly as plants rather than food.

One result of treating plant-based foods as plants is that the MeSH term is usually the botanical plant name; in the case of chocolate it’s Cacao. This is usually not a serious problem when searching for specific substances because the common food name maps to the botanical MeSH term.

A more serious consequence of treating plant-based foods as plants instead of foods is that they are usually not in any food-related explosion, but only in the Plants explosion. So the only occurrence of chocolate (Cacao) is here:

Plants
   Angiosperms
      Sterculiaceae
         Cacao

The reason this is a problem is because articles on chocolate/Cacao will not be retrieved in a search for Food. So, for example, if you do a general search for food-related causes of migraine, you will not retrieve this article:

Chocolate is a migraine-provoking agent
Journal: Cephalalgia
http://www.ncbi.nlm.nih.gov/pubmed/1860135

This is not retrieved by searching for food because Cacao is not in the Food explosion. More broadly, however, it’s also not retrieved with the comprehensive Food-Diet-Nutrition hedge that we’ve discussed previously, which includes text-words as well MeSH terms and explosions.

Here are several other articles on health and medical aspects of chocolate that are not retrieved by our broad Food-Diet-Nutrition hedge:

If chocolate were the only case of a plant-based food that is not retrieved in a broad PubMed search for food-related topics, it would be a trivial matter. But that’s far from being the case. There are many plant-based foods that have the same problem in PubMed. We will be writing on several of these foods in the next few months, so keep an eye on this space!

 

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Medical & Nursing Journals – A Twitter List

By Sarah Andrews and Eric Rumsey

Many medical and nursing journals now use Twitter. On their Twitter sites, they share links to journal articles and sometimes other news items in the field. We have made a Twitter list with 116 of these journal sites:

https://twitter.com/HardinLib/lists/journals

The base of our list is the National Library of Medicine’s list of Core Clinical journals. There are 119 titles in that list, and we were able to find Twitter feeds for about 75 of them. The other Twitter sites on our list we found in Laika Spoetnik’s Twitter journal list and from Googling likely word combinations.

Not all tweets are for journal articles. The proportion of tweets that are journal articles, as opposed to other news items, varies in different journal feeds.

 

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Holy Carnitine! @Altmetric Is On To Something Big!

In our previous article, we talked about a ranking list done by Altmetric of the most popular research articles of 2013. An interesting anecdotal story at the Reference desk just a couple of days after publishing the article, I think, gives strong confirmation of the validity of the Altmetric ranking.

As I was working at the Reference desk, a library patron using a workstation in the reference area [who turned out to be Charles Rebouche, see more below] asked for help with a printing problem he was having. As I approached his station I couldn’t help noticing that the article he was trying to print was on Carnitine, which happened to be a prominent subject of one of the articles that was on the Altmetric ranking. I was especially struck when I noticed this because before I saw the Altmetric ranking list in December, I had never heard of carnitine. As I learned in writing about the Altmetric ranking though, it turns out that carnitine is an ingredient of red meat (and also many energy drinks) that’s implicated in new research as a possible contributor to cardiovascular disease.

After the patron’s printing problem was resolved, I talked to him about his interest in carnitine. Interestingly, I learned that he’s an emeritus faculty member who has spent much of his career on researching carnitine. I told him about my work with the Altmetric list, and about the article that was ranked as being one of the most popular research articles of 2013. He knew all about the surge in popularity of the subject that accompanied the article, he said, because he’s been asked to “come out of retirement” to do a presentation about carnitine, which is why he was in the library catching up on the latest research.

So, on one level, a cute, satisfying story about the rewards of working at the Reference desk. But beyond that, I think this little story shows that the Altmetric ranking is more than an abstract application of “big data,” that Altmetric popularity does indeed have a real effect that’s felt by real researchers!

[Dr. Rebouche has read and approved of this article. He has indeed done voluminous research on carnitine, as attested by his 41 PubMed citations!]

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Food, Diet & Nutrition: Popular Subject, Difficult PubMed Search

By Eric Rumsey and Janna Lawrence

In December, Altmetric published a list of the most popular research papers of 2013 <http://www.altmetric.com/top100>. The Altmetric site has developed a method to quantify popularity by using social media and traditional media to measure the “buzz” about particular articles. Of the top 64 articles on the altmetric list, a surprisingly high 19% of them (12 articles) are on food, diet and nutrition (FDN). In comparison, by our count the number of citations in the top 64 for other popular topics are: Brain/Neuro 9, Sleep 5, Heart/Cardio 3, and Cancer 3.

The popularity of FDN strikes us especially because we have recently written on this blog about the difficulty of searching FDN subjects in PubMed. The Altmetric list provides a good opportunity to test our ideas on FDN subjects that are identified by Altmetric data as being especially  popular.

Shown below are the 12 articles in the top 64 articles in the Altmetric ranking that are on FDN, with PubMed links and FDN-related MeSH terms that are used for each of the articles (the asterisk after some headings indicates that the subject is given major emphasis in the article). At the end of the list, we’ll have a few brief comments on MeSH indexing problems.

FDN-related articles on the Altmetric Top 100 Research Articles of 2013

#2 (See comments on this article at bottom)
Primary Prevention of Cardiovascular Disease with a Mediterranean Diet
New England Journal of Medicine
http://www.ncbi.nlm.nih.gov/pubmed/23432189
FDN-related MeSH terms:
Diet, Fat-Restricted
Diet, Mediterranean*
Dietary Supplements
Nuts*
Plant Oils*

#8
Association of Nut Consumption with Total and Cause-Specific Mortality
New England Journal of Medicine
http://www.ncbi.nlm.nih.gov/pubmed/24256379
FDN-related MeSH terms:
Diet*
Diet Surveys
Nuts*

#15 (See comments on this article at bottom)
Impact of insufficient sleep on total daily energy expenditure, food intake, and weight gain
Proceedings of the National Academy of Sciences
http://www.ncbi.nlm.nih.gov/pubmed/23479616
FDN-related MeSH terms:
Eating/physiology*
Weight Gain/physiology*

#19
The Autopsy of Chicken Nuggets Reads “Chicken Little”
The American Journal of Medicine
http://www.ncbi.nlm.nih.gov/pubmed/24035124
FDN-related MeSH terms:
Dietary Fats/analysis
Dietary Proteins/analysis
Fast Foods/analysis*
Poultry Products/analysis*

#23
Myths, Presumptions, and Facts about Obesity
New England Journal of Medicine
http://www.ncbi.nlm.nih.gov/pubmed/23363498
FDN-related MeSH terms:
Breast Feeding
Diet, Reducing
Obesity*/physiopathology
Obesity*/prevention & control
Obesity*/therapy
Weight Loss*

#26
Prospective Study of Breakfast Eating and Incident Coronary Heart Disease in a Cohort of Male US Health Professionals
Circulation
http://www.ncbi.nlm.nih.gov/pubmed/23877060
FDN-related MeSH terms:
Breakfast*
Food Habits*

#33
DNA barcoding detects contamination and substitution in North American herbal products
BMC Medicine
http://www.ncbi.nlm.nih.gov/pubmed/24120035
FDN-related MeSH terms:
Not yet indexed

#38
Persistence of Salmonella and E. coli on the surface of restaurant menus
Journal of Environmental Health
http://www.ncbi.nlm.nih.gov/pubmed/23505769
FDN-related MeSH terms:
Food Microbiology*
Foodborne Diseases/microbiology
Foodborne Diseases/prevention & control*

#54
Meat consumption and mortality – results from the European Prospective Investigation into Cancer and Nutrition
http://www.ncbi.nlm.nih.gov/pubmed/23497300
FDN-related MeSH terms:
Diet/adverse effects*
Feeding Behavior*
Meat*
Nutrition Surveys

#58
The Relationship of Sugar to Population-Level Diabetes Prevalence: An Econometric Analysis of Repeated Cross-Sectional Data
PLOS ONE OPEN ACCESS
http://www.ncbi.nlm.nih.gov/pubmed/23460912
FDN-related MeSH terms:
Carbohydrates/analysis*
Obesity/epidemiology

#60
Inverse relationship of food and alcohol intake to sleep measures in obesity
Nutrition & Diabetes
http://www.ncbi.nlm.nih.gov/pubmed/23357877
FDN-related MeSH terms:
This journal is not currently indexed in PubMed/MEDLINE

#64 (See comments on this article at bottom)
Intestinal microbiota metabolism of l-carnitine, a nutrient in red meat, promotes atherosclerosis
Nature Medicine
http://www.ncbi.nlm.nih.gov/pubmed/23563705
FDN-related MeSH terms:
Meat

Our comments on the Altmetric list

The twelve FDN citations in the Altmetric rankings cluster around three subjects – Plant-based foods: #2, #8, # 33; Obesity & Weight Gain: #15, #23, #58, #60; and Meat: #19, #54, #64. In a brief examination of the list, we can see that there are MeSH problems in each of these areas, most notably in these citations, one in each of the three clusters:

  • Plant-Based Foods - #2 (Primary Prevention of Cardiovascular Disease with a Mediterranean Diet) – Olive oil, a major top of this article, is indexed in MeSH as Plant Oils. This is not in the Food explosion, or any other FDN explosion, so it’s not picked up by a comprehensive search for FDN subjects.
  • Obesity and Weight Gain – #15 (Impact of insufficient sleep on … food intake, and weight gain). This is indexed in MeSH as Weight gain, and not as Obesity. The latter term is retrieved by a broad FDN search because it’s in the Nutrition disorders explosion. The seemingly closely-related term Weight gain is not in that explosion, and is therefore not retrieved in a broad FDN search.
  • Meat – #64 (Intestinal microbiota metabolism of … red meat, promotes atherosclerosis) - “Red Meat” is generally considered to be beef, pork and lamb – Because none of these has separate MeSH terms, the article is indexed only as Meat. This is a problem because when that term is searched in PubMed, it is automatically exploded, and the exploded heading includes not just meat, but also fish and poultry. Even when searching for Meat as an unexploded term includes some articles for poultry and fish.

We have written previously on the problems of searching in PubMed for Plant-Based Foods. We will write in the future here on the other topics above – Obesity and Meat.

Acknowledgements:

  • Thanks to Colby Vorland (‏@nutsci) who first noted in a tweet the popularity of FDN in the Altmetric ranking.
  • Thanks to Chris Shaffer, for a close reading of our article and useful comments.
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PubMed’s Secret Ingredient: Explosions

By Eric Rumsey, Janna Lawrence, and guest author Chris Shaffer, former Hardin librarian, now University Librarian, Oregon Health & Science Univ

Explosions are a powerful, built-in feature of PubMed that make it easy to search for clusters of related subjects. Because they’re so seamlessly incorporated into PubMed, it’s possible to search the database without having any knowledge of explosions. But to get the best results, it helps to understand how they work.

CardiovasDis67

The clip from the MeSH database to the left gives an idea of the hierarchical “tree structure” of explosions. When you search in PubMed for a MeSH term that’s at the top of a category, the search automatically includes all of the terms indented under it. So for instance, if you search in PubMed for Cardiovascular Abnormalities, the two terms indented under it are also included. The “+” sign after these terms indicate that they are explosions that have other terms under them, which are also included.

To see details of specific exploded terms, search the MeSH Database. (To see the page for Cardiovascular Diseases, in the example at left, click the graphic, or click here)

Much of the elegance of explosions is the ability to search large categories, and to move up and down “the tree” to try out more or less specific terms. For example, let’s say you’re interested in the subject of exercise and heart diseases. Combining those concepts in PubMed, you find there are more than 7000 citations. So, how many citations are there about the broader concept of cardiovascular diseases and exercise? With the power of PubMed’s automatic explosions, it’s easy to see that there are about double the number. And, of course, it’s easy to move the other direction in the tree, to do the search with specific terms and explosions anywhere in the hierarchy.

Another key reason explosions are so valuable is that articles are indexed only to the most specific MeSH term. An article on Cardiac Tamponade, for example, will only be assigned that term, and not the broader term Heart Diseases. Without explosions, it would not be found by searching for Heart Diseases. But because it’s in the Heart Diseases explosion, it is found.

Why “Secret Ingredient”?

We call explosions PubMed’s “Secret Ingredient” because they are very powerful but little-known and/or taken for granted. It wasn’t always this way – When the Medline database (which is what you’re searching in PubMed) was in its early days, in the 1980′s, explosions certainly were acknowledged to be a “big deal” – With the relatively low-powered computers of the time, explosions took big chunks of computer time, and were used with caution. With today’s computers, of course, this is only a distant memory, and, fortunately, no one needs to worry about using explosions.

A further reason that explosions have receded into the background is that, with the advent of Google-style simple search interfaces, PubMed has adopted the same sort of simple interface. This has had the effect of making people less aware of what PubMed is doing “under the hood.” With the simple, Google-like interface of PubMed, it’s natural to think that it works “just like Google.” But in fact it’s quite different - With only a bit of oversimplifying, the basic difference is that Google searching is purely computer-based and PubMed is based on human indexing. Humans actually read every article in PubMed, and assign 10-15 MeSH terms, which is what makes explosions possible.

How to search without an explosion

When you search for a subject in PubMed, the default is for it to explode the MeSH term that’s associated with the subject, and this is almost always what you want, since articles are indexed with the most specific term available. For example, an article about cardiac arrhythmias will be indexed as Arrythmias, Cardiac, and not to its broader heading, Heart Diseases. There may be occasions, however, when you only want the MeSH term at the top of the category, without subsidiary terms. The way to do that search, using the example discussed here, is to search for: Heart Diseases [mh:noexp]. Another way to do this is to click the box that says “Do not include MeSH terms found below this term in the MeSH hierarchy” on the MeSH Database display for Heart Diseases.

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Plant-Based Foods – A Tricky PubMed Search

By Eric Rumsey and Janna Lawrence

As discussed in an earlier article, searching for Food-Diet-Nutrition in PubMed is difficult because the subject is spread around in several different places in the MeSH classification system. In another article, we provide a way around this, which provides a broad set of search terms that can be used to search for the subject. An aspect of the subject, however, that cannot be put in a “package” that makes it possible to search together as a group is plant-based foods.

The Food cluster-explosion contains many specific foods, as MeSH headings, including some plant-based foods. A large proportion of all plant-based foods, however, are not in the Food cluster-explosion, but are only in Plants, and not in Food. These, of course, will not be retrieved by searching for “Food.” Adding to the confusion, some vegetables (but no fruits) are in both categories. Here are some examples:

Sweet potato is put under the MeSH term Ipomoea batatas. Its only place in the MeSH tree is in the Plants explosion:

Plants
   Angiosperms
      Convulvulaceae
         Ipomoea
            Ipomoea batatas

As noted above, this will not be retrieved by searching for “food.”

Kale (MeSH term Brassica), on the other hand, is included in both Plants and Food and so it will be retrieved by searching for “food”:

Plants
   Angiosperms
      Brassicaceae
         Brassica
Food
   Vegetables
      Brassica

The examples for sweet potato and kale bring to light another point of confusion, which is that terms in the Plants explosion are usually botanical names that are not recognizable to most people. A few examples (all of which are only in the Plants explosion but not in the Food explosion):

Grapes is Vitis
Strawberry is Fragaria
Okra is Abelmoschus
Kidney Beans is Phaseolus
Chocolate is Cacao
Turmeric is Curcuma

This is usually not a problem when searching for specific food plants, because when searching for a common name, it’s mapped to the botanical MeSH term (e.g. if you search for Grapes, it maps to Vitis). The problem comes if you want to browse the Plants cluster to pick out the edible plants from the many plants that are not edible, because only the botanical names are listed. The Rose family (Rosaceae) of plants, for example, has several edible species within it. There are 19 genera listed in MeSH in the family, and 6 of them have edible species. But to find them, you have to be able to pick out the genera with edible species (e.g. Malus, Prunus) from the others (e.g. Agrimonia, Alchemilla).

A caveat: There is an exploded MeSH term Plants, Edible, which might seem to be a good place to search for plant-based foods. Unfortunately, however, it’s of limited usefulness – The explosion contains only grain plants and a relatively small number of vegetables, and the term Plants, Edible itself is mostly used to index articles that are on the general concept rather than articles on specific types of edible plants.

A qualification: What we say here about the difficulty of doing comprehensive PubMed searches that include all specific plant-based foods applies to a lesser degree to other types of foods also. Looking, for example, at Meat in the MeSH classification of Food, there are no headings for specific types of meat (e.g. beef, pork), so they’re all indexed under the broader term Meat. The reason the problem is so much more complicated for plant-based foods is because there are so many of them, and also because the line between plant-based foods and plant-based medicines is often fuzzy.

Advice on searching for plant-based foods

Consider combining Plants with your subject – The Plants explosion in MeSH is very large, containing hundreds of plant species. It’s organized by taxonomic relationships, which makes it hard for a non-botanist to browse. But it’s useful to combine with other subjects in searching, because it’s so comprehensive. The main drawback in searching it is that in addition to plant-based foods, it also has many plant-based drugs, which you’ll have to sift out from the food articles.

If you want to restrict your search to plant-based foods, instead of foods in general, you can combine the Plants explosion AND the Food-Diet-Nutrition hedge search discussed in a previous article.

If you combine your subject with the hedge in the previous article and it misses articles on particular plant-based food, search specifically for those. If you do a search for food and migraine, for example, and your search doesn’t pick up specific foods that you know have been associated with migraine (e.g. chocolate), combine those foods specifically with migraine.

 

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Food, Diet & Nutrition – An Inclusive PubMed Search

By Eric Rumsey and Janna Lawrence

As discussed in a previous article, searching for Food, Diet, and Nutrition in PubMed is tricky because the relevant Medical Subject Headings (MeSH) for the subject are scattered widely in the classification scheme. To do a thorough search, therefore, it’s necessary to use a number of terms. To make this easier, we have created a search strategy, or hedge, that combines most of the Food-Diet-Nutrition terms in one search.

The hedge search, of course, is much too large to be useful by itself (it gets over 1.5 million citations in PubMed). So it’s intended to be combined with another subject. A typical example would be finding the nutritional aspects of a disease.

Here is the hedge:

food OR foods OR beverages OR diet OR dietary OR vitamin OR vitamins OR nutrition OR nutritional OR nutrition disorders OR food industry OR nutritional physiological phenomena OR dietary fats OR dietary proteins OR feeding behavior

To use this search, click this link. You can also copy the text above and paste it into the PubMed search box. If you have a personal “My NCBI” account in PubMed, the hedge search can be saved for later use, or it can be made into a search filter. For information on setting up and using saved searches, see here; for more information on filters, see here.

List of terms in the hedge. Terms on the list that have no accompanying text are searched only as text-words (words appearing in article titles or abstracts), and as words that are part of MeSH terms.Terms below that are found in MeSH (which are also automatically searched as text-words) have brief commentary.

Disclaimer: This hedge is not ALL-inclusive for Food-Diet-Nutrition. As complicated as the subject is, it’s not possible to include all of the relevant terms in one search. This is especially the case because most plant-based foods are not in any category that can be searched together. The Food explosion does include many specific foods, but most plant-based foods are only in the Plants explosion, and not in the Food explosion. For tips on searching for plant-based foods, see here.

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