The interaction of path integration and terrestrial visual cues in navigating desert ants: what can we learn from path characteristics? [RESEARCH ARTICLE]

Cornelia Buehlmann, A. Sofia D. Fernandes, and Paul Graham

Ant foragers make use of multiple navigational cues to navigate through the world and the combination of innate navigational strategies and the learning of environmental information is the secret of their navigational success. We present here detailed information about the paths of Cataglyphis fortis desert ants navigating by an innate strategy, namely path integration. Firstly, we observe that the ants’ walking speed decreases significantly along their homing paths, such that they slow down just before reaching the goal, and maintain a slower speed during subsequent search paths. Interestingly, this drop in walking speed is independent of absolute home-vector length and depends on the proportion of the home vector that was completed. Secondly, we find that ants are influenced more strongly by novel or altered visual cues the further along their homing path they are. These results suggest that path integration modulates speed along the homing path in a way that might help ants search for, utilise or learn environmental information at important locations. Ants walk more slowly and sinuously when encountering novel or altered visual cues and occasionally stop and scan the world, this might indicate the re-learning of visual information.

Our Living Planet Shapes the Search for Life Beyond Earth

Pasadena CA (JPL) Nov 16, 2017
As a young scientist, Tony del Genio of NASA's Goddard Institute for Space Studies in New York City met Clyde Tombaugh, the discoverer of Pluto. "I thought, 'Wow, this is a one-time opportunity,'" del Genio said. "I'll never meet anyone else who found a planet." That prediction was spectacularly wrong. In 1992, two scientists discovered the first planet around another star, or exopla

Biocatalysts could be powerful tools for chemists

New research is building a bridge from nature’s chemistry to greener, more efficient synthetic chemistry.

Researchers analyzed biocatalysts evolved by nature for their effectiveness in a variety of synthetic chemical reactions. The results, published in Nature Chemistry, open the door to promising practices for chemists, pointing to not only more efficient but also more powerful tools for chemists.

The researchers started with microorganisms that have, over the millennia, developed complex chemical reactions to create molecules with important biological activity for various purposes, such as defense mechanisms. The scientists then analyzed the chemical pathways that give rise to these potentially useful molecules to determine how they can be repurposed to create compounds synthetically in the lab.

“Nature has evolved catalytic tools that would enable chemists to build molecules that we can’t easily build just using traditional chemistry,” says senior study author Alison Narayan, assistant professor at the University of Michigan Life Sciences Institute. “Our work bridges the two worlds of biosynthesis and synthetic chemistry.”

Lots of waste

To build complex, bioactive molecules—like the molecules that allow drugs to find the right biological targets in our bodies—synthetic chemists often use a process called oxidative dearomatization. This process converts flat molecules into three-dimensional structures that are more reactive. But traditional oxidative dearomatization methods have several flaws.

“We are really starting to build the library of new, efficient, powerful tools for chemists.”

Because they require the use of a chemical reagent to convert the starting material into the desired end product, the reactions themselves are fairly wasteful. In addition, the reagents demonstrate poor selectivity in the transformation, resulting in a mixture of compounds that contains several unnecessary, and sometimes harmful, variants of the desired product molecule.

“It’s not a very efficient process,” says Narayan, who is also an assistant professor of chemistry. “You can end up with various structures when you really want only this one specific structure—and you generate a lot of waste in the process.”

Efficient enzymes

In this recent study, the Narayan lab demonstrated that enzyme catalysts have the potential to solve these issues.

Enzymes are efficient catalysts, generating many product molecules from a single molecule of the catalyst, leading to less waste. And Narayan’s lab found that the catalysts perform the reactions with improved selectivity—meaning that the reactions produce only the desired molecular structure.

How enzymes direct ‘traffic’ inside cells

Chemists haven’t yet widely adopted these enzymes because their overall utility and robustness for chemistry have not been demonstrated, Narayan says.

“The work being done in the field of biosynthesis primarily focuses on understanding how molecules are made in nature and identifying the single reaction an enzyme does in its natural context,” she says. “We have to figure out how an enzyme is useful in the field of synthetic chemistry—what can it do, what types of molecules it works with—so that chemists can just go to the literature and see how they can use this tool.”

Narayan’s research program begins to close the gap between these two fields by testing enzymes not just for their natural roles, but for the roles they could play in a variety of reactions. The lab also has developed methods to make these enzymes easy to handle in bulk and share with other chemists.

“We’re showing that these enzymes can do more than the one specific task they evolved to do in nature,” says graduate student Summer Baker Dockrey, the lead study author. “They can be surprisingly generalizable and could prove to be highly selective tools.”

Enzyme discovery could offer new malaria drugs

The lab is now working on engineering these enzymes to perform more reactions.

“We are really starting to build the library of new, efficient, powerful tools for chemists,” Narayan says.

Funding for the work came from LSI, the University of Michigan chemistry department, the National Institutes of Health, and the US Department of Education.

Source: University of Michigan

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Book Review: A Survival Kit for Doctoral Students and Their Supervisors


Survival Kit cover

A Survival Kit for Doctoral Students and Their Supervisors: Traveling the Landscape of Research by Lene Tanggaard and Charlotte Wegener. SAGE Publishing. 2016.

When I am not really in the mood to do actual research, one of my favorite procrastination strategies is to read books on how to do research. (Ironically many of these books in turn offer tips on how to avoid procrastination.) Fortunately or unfortunately, there is a multitude of websites, articles and books offering advice on every conceivable aspect of doctoral research, not to mention articles about books about doctoral research. Therefore a new entrant to the field must work hard to distinguish itself, and in A Survival Kit for Doctoral Students and Their Supervisors, Tanggaard and Wegener claim that their “intention is to get closer to the actual and messy practices of doctoral training than many ‘how-to’ books ever come.”

LSE Books logo

This review by Sroyon Mukherjee originally appeared on the LSE Review of Books blog and is reposted under the Creative Commons license (CC BY 3.0).

How successful is their endeavor? Before addressing that question, I would briefly note that the book is different in at least two other ways. First, unlike most books in what may be called the ‘doctoral self-help genre’, Survival Kit addresses both students and supervisors. Second, the authors are both professors in the Department of Communication and Psychology at Aalborg University, but it turns out Tanggaard was Wegener’s doctoral supervisor, and this allows them to draw on a number of shared anecdotes and insights.

In Chapter One, which spells out the theoretical basis of the book, the authors argue for an “apprenticeship perspective on doctoral training and supervision.” But what does this mean, and how does it differ from conventional ideas about doctoral research? The apprenticeship perspective, we are told, involves ‘an emphasis on research as a result of yearlong practice and involvement in research environments’ (1). Its central idea is that “more experienced people assist less experienced ones, providing structure and examples to support the attainment of goals,” and that it “builds upon a perception of research as grounded in activities that are associated with established knowledge and intuitive expertise.”

The exposition, as is perhaps apparent from these excerpts, is couched in rather abstract terms which may be confusing – or worse, off-putting – for readers without a background in education theory. Nonetheless, it is an interesting premise. It draws on the work of Tanggaard and Wegener’s late colleague, Steinar Kvale, who argued for the extension of the apprenticeship paradigm to academic research. Kvale, in turn, was inspired by Lave and Wenger’s theory of situated learning, which may be defined as ‘learning that takes place in the same context in which it is applied’. Here, learning is seen not as a transfer of abstract knowledge from master to student, but as a product of ‘legitimate peripheral participation in communities of practice’ (Lave, 1991).

But a book such as this must ultimately be judged on the quality of its advice; its theoretical underpinnings are of secondary importance. Accordingly, the practical implications of the apprenticeship perspective are explored in Chapters Two to Eight, which offer advice on a range of topics from choosing a supervisor all the way to finalizing the dissertation.

Each chapter begins with an abstract and ends with bullet-point suggestions for the PhD student and the supervisor. Some suggestions are too vague or general to be of real value (“Make sure to get the best out of the research landscape you are now part of’”, but others are genuinely useful (“Embrace confusion and uncertainty; and seek out ways to mine these feelings for research gold – keep a “confusion diary,” […] or invite people you like to a “getting lost study group”’). For me personally, one piece of supervisor advice came as a pleasant surprise: “Use creative [feedback] practices as they do at London School of Economics.”

Curiously, when it comes to substantive content, the authors seem to switch between two distinct modes of presentation. There are whole sections which read like a review of theoretical literature, more appropriate to a research article than a book of this kind. For instance:

Jazvac-Martek et al. (2011) note that doctoral students’ academic futures depend on their ability to extend and maintain a network of relationships. McAlpine, Paulson, Gonsalves, and Jazvac-Martek (2012) point to the fact that students who completed their theses were able to operate independently but sought the emotional support of others…

I could not resist comparing this passage with Umberto Eco’s equivalent advice in How to Write a Thesis: “Do not play the solitary genius.”

Doctoral students are well accustomed to making sense of dense academic prose, but Survival Kit would be much more readable if the theoretical digressions and extensive references were dealt with in the first chapter, consigned to the endnotes or, in some cases, omitted altogether. On the other hand, some of the direct quotes (as opposed to paraphrased conclusions) are truly illuminating: ‘I write in order to learn something that I did not know before I wrote it’ (80, quoting Laurel Richardson).

The book is much more successful when the authors write in the second mode, which is a combination of personal anecdotes, case studies and freewheeling reflections – in short, where they show rather than tell us about good doctoral and supervisory practice. Chapter Seven, which is about feedback, quotes a series of emails between Wegener and a journal editor, giving us a rare glimpse into the dreaded peer review process. The authors also include instructive first-hand accounts from colleagues: this is in keeping with the idea that “peers and masters are everywhere” (the title of Chapter Five). As someone who changed his research topic halfway through his first year, I particularly identified with “Sven’s story about jumping on the right train.”

Success stories like that of Sven are typically more widely reported than stories of failure, so I was intrigued by Rasmus Birk’s account of being dismissed from a research position, from which the authors draw the heartening conclusion: ‘failure is not the end of the world’ (30). I for one would welcome the inclusion of more such stories and advice on ‘what not to do’, as a counterpoint to the book’s many positive narratives and constructive suggestions.

Some doctoral theses are destined to become classics, while many others, depressingly, gather dust in departmental archives. So it is with doctoral advice books. Few can match up to the timeless appeal of Umberto Eco’s How to Write a Thesis or Howard Becker’s Writing for Social Scientists, but this does not mean there is nothing left to be said on the subject. Survival Kit is perhaps a book to be skimmed rather than read from cover to cover – the dry theoretical passages are best left alone, but some of the anecdotes, case studies and email exchanges really do allow us to get “closer to the actual and messy practices of doctoral training.”


The post Book Review: A Survival Kit for Doctoral Students and Their Supervisors appeared first on Social Science Space.

China and the US are both shooting for the moon

Bristol UK (The Conversation) Nov 10, 2017
On the face of it, it looks like two of the world's biggest powers are racing to get astronauts back on the lunar surface. China is aiming to land crew on the moon by 2036, while on the other side of the Pacific, US vice president, Mike Pence, has announced that the US will return there too. But declaring that a new space race is underway is probably the single quickest way to irritate space pol
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