Molecular Imaging: Seeing Cancer in Action Inside the Body
Oct. 8, 2009 – Molecular imaging can reveal how cancer cells communicate, how they move, what they need to survive and where they are vulnerable to attack. In this edition of Breakthroughs in Cancer Research, David Piwnica-Worms, MD, PhD, professor of developmental biology and radiology at Washington University School of Medicine, explains how molecular imaging is different from more traditional radiology techniques and discusses new discoveries coming out of the medical school’s Molecular Imaging Center.
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TRANSCRIPT OF AUDIO FILE
On this edition of Breakthroughs in Cancer Research, we’ll talk about how scientists are making it possible to see cancer in action inside the body. That’s providing new information on how to destroy cancer cells.
Host: Thanks for downloading this podcast from the Siteman Cancer Center at Barnes-Jewish Hospital and Washington University School of Medicine in St Louis. I’m Gwen Ericson. With techniques collectively called molecular imaging, scientists are finding new ways to detect cancer early, monitor cancer treatment and develop better cancer drugs. Molecular imaging can reveal cancer’s secrets, showing how cancer cells communicate, how they move, what they need to survive and where they are vulnerable to attack. To tell us more is David Piwnica-Worms. He is director of the Molecular Imaging Center at the Mallinckrodt Institute of Radiology and the Siteman Cancer Center. Dr. Piwnica-Worms, thank you for joining us.
Piwnica-Worms: Well thank you, Gwen. I’m happy to talk with you today.
Host: Most of us have had experience with traditional kinds of medical imaging – things like X-rays, PET scans and ultrasound scans. But we’ve probably never encountered molecular imaging. Tell us about the distinction between traditional medical imaging and molecular imaging.
Piwnica-Worms: In most of the traditional medical imaging that we may have experienced as patients or with family members, the focus of the imaging is on the anatomy and, in the context of cancer, on the mass or the size of the mass. But in molecular imaging, we’re actually interested in the details of the molecules that are inside the cancer. That is the biology or the biochemistry or metabolism of the cancer. We’re actually trying to image changes in those molecules and biochemistry that may even precede changes in the anatomy.
Host: Give me an example of a molecular imaging technique.
Piwnica-Worms: One strategy is in the general area that we call genetically encoded reporters. And that means we may take some genetic material from one organism and transfer it into another that may have favorable imaging properties. One such example that we make common use of is firefly luciferase. That is the same firefly that we see flying around in our backyards on a July day in St Louis. And the gene that actually makes the fireflies glow is called luciferase. We can actually use standard molecular biology and cloning techniques to transfer that luciferase gene from fireflies into a cancer cell, and we can watch the cancer glow and move around the body. Or it may tell us how it glows in response to different genes being expressed, or maybe how a protein, one of the building blocks, is processed. And those signals can tell us something about the metabolism and the gene expression inside those cancer cells using noninvasive imaging cameras.
Host: Tell me more about what techniques like that reveal about cancer.
Piwnica-Worms: One way to think of this is that cancer is like a baseball game where we don’t understand the rules. And you can imagine if you were taking a snapshot of Pujols at bat in the first inning, and then sometime later in the third inning you had a snapshot of Holliday running around a base path. And then at some other time, you had a snapshot of Ankiel making a long throw to third base from the outfield. What are the underlying rules that allow that to happen? If you knew nothing about the game of baseball and you had to try to put these together, dynamic views, continuous videos and movie loops would allow you to begin understanding those rules of why sequential events occur in a more dynamic and easy way than a series of random snapshots. And we hope that analogy sort of lets you know how we can look dynamically, continuously, over time with these noninvasive molecular imaging strategies at the baseball game of cancer that’s going on inside the cells.
Host: In medical terms, what can molecular imaging do for us?
Piwnica-Worms: A lot of the activities do relate to preclinical and basic type of cancer biology work. These help us better understand the cancer pathways, the rules that guide the metabolism of the cancer cell. These represent the new targets of tomorrow, where new drugs and combinations of drugs can actually help patients. And in some special cases, maybe even in a human, we can tag the drug and understand, is it actually hitting the cancer? Is it binding to its molecular target? And we can image that noninvasively and repetitively over time. And in another area that relates more directly to patients, there are some techniques like fluorodeoxyglucose (FDG) PET. And this is a special subset of molecular imaging that is available today that does look at sugar metabolism in cancer. It can help us detect cancer at early stages or help guide therapeutic choices. That’s one area of molecular imaging that’s actually in the clinics today.
Host: What are some of the latest discoveries to come out of the Molecular Imaging Center?
Piwnica-Worms: We have a lot of activities going on both within our core groups and collaborators. Two areas of interest that have recently been published and explored involve one of these special pathways. It’s known scientifically as the beta-catenin pathway. It’s very, very important in colon cancer, and it also affects how cells grow and metastasize. And by using one of these luciferase strategies, we can now follow the time course of the regulation of the beta-catenin protein inside colon cancer cells.
Another area that’s been very interesting for us is we developed a new optical technique to look directly at inflammation in living animals. In inflammation that occurs around cancer, there is an enzyme known as myeloperoxidase. And it ends up that a small molecule that many people are familiar with known as luminal – which is the same small molecule that you see on CSI Miami that’s sprayed on blood – has a very highly sensitive response to the enzyme myeloperoxidase, which is one of the key enzymes in inflammation. We’ve developed some techniques now using that luminal where we can now look at this myeloperoxidase-mediated inflammation in mouse models, and maybe someday we might be able to look at that in humans and help us follow inflammatory processes related to cancer.
Host: Tell me about what the Molecular Imaging Center itself is like.
Piwnica-Worms: Well, the Molecular Imaging Center itself is really two main components – a physical center, if you will, and a virtual center. The physical center is the founding faculty investigators who are physically in our laboratory space, all interacting on a daily basis with our laboratories, ourselves and the imaging cores that are in my lab and the investigators’ labs around. And then in addition, we’re tied together by a National Institutes of Health Molecular Imaging Center grant that helps support the cores and the broad array of investigators. We have projects that are ongoing with collaborators in cancer biology and immunology and pharmacology and biochemistry – all interested in studying biology noninvasively through these molecular imaging strategies so that we can try to pry basic biology done with traditional reductionist approaches together with these new dynamic strategies in living cells and live animals and ultimately patients.
Host: Dr. Piwnica-Worms, thank you for joining us.
Piwnica-Worms: You’re welcome.
Host: If you are interested in learning more about the Molecular Imaging Center, please visit its Web site at mic.wustl.edu.


BSA Supply No. 35940
If you have ever wanted to go back in time or wished you could visit the future, if you are curious about the world, or if you are interested in how things work or like to learn new things, these are all reasons why you should want to read. Reading is fascinating. It's full of surprises. And it will take you places you can't get to in any other way.
- Do EACH of the following:
- Learn how to search your library's card catalog or computerized catalog by author,
title, and subject.
- With the assistance of your merit badge counselor or a librarian, select six books
of four different types (such as poetry, drama/plays, fiction, nonfiction, biographies,
etc.). Ask your librarian or counselor about award-winning books that are recommended
for readers your age and include at least one of those titles.
- Find the books in the library catalog. With your counselor's or a librarian's assistance,
locate the books on the shelves.
- Read each book. Keep a log of your reading that includes the title of the book,
the pages or chapters read, the date you completed them, and your thoughts about
what you have read so far. Discuss your reading with your counselor. Using your
log as a reference, explain why you chose each book and tell whether you enjoyed
it and what it meant to you.
- Read about the world around you from any two sources--books, magazines, newspapers,
the Internet (with your parent's permission), field manuals, etc. Topics may include
sports, environmental problems, politics, social issues, current events, nature,
religion, etc. Discuss what you have learned with your counselor.
- Do ONE of the following:
- From a catalog of your choice, fill out an order form for merchandise as if you
intended to place an order. Share the completed form with your counselor and discuss
- With your parent's permission, locate at least five Web sites that are helpful for
your Scouting or other activities. Write the Internet addresses of these sites in
your log. Talk with your counselor or a librarian about safety rules for using the
- With your counselor's and your parent's permission, choose ONE of the following
activities and devote at least four hours of service to that activity. Discuss your
participation with your counselor.
- Read to a sick, blind, or homebound person in a hospital or in an extended-care
- Perform volunteer work at your school library or a public library.
- Read stories to younger children, in a group or individually.
- Best Books for Young Adults - http://www.ala.org/ yalsa/booklists/bbya
- BookSpot: Young Adult Books - http://www.bookspot.com/ youngadult.htm
- Choices Booklists - http://www.reading.org/ choices
- National Book Awards for Young People's Literature - http://www.literature-awards. com/national_book_awards.html
- Newbery Medal Winners and Honor Books - http://www.ala.org/alsc/ newbpast.html
- 100 Best Books for Children - http://www.teachersfirst.com/ 100books.htm
- Summer Reading Lists - http://www.educationworld. com/summer_reading
- Teenreads.com - http://www.teenreads.com
- U.S. Children's Book Awards - http://www.ucalgary.ca/~dkbrown/ usawards.html
- The Online Books Page - http://digital.library.upenn.edu/books
- Project Gutenberg - http://gutenberg.net
P.O. Box 152350
Irving, TX 75015-2350
Web site: http://www.boyslife.org
30 Grove St., Suite C
Peterborough, NH 03458
Toll-free telephone: 800-821-0115
Web site: http://www.cobblestonepub. com/pages/callmain.htm
Cicada and Cricket
P.O. Box 7434
Red Oak, IA 51591-0433
Toll-free telephone: 800-821-0115
Web site: http://www.cricketmag.com
149 Fifth Ave.
New York, NY 10010
Web site: http://www.kidsdiscover.com
SAS Campus Drive
Cary, NC 27513
Web site: http://www.ncsu.edu/midlink
National Geographic Kids
P.O. Box 63002
Tampa, FL 33663-3002
Toll-free telephone: 800-647-5463
Web site: http://www.nationalgeographic. com/ngkids
P.O. Box 3939
Eugene, OR 97403
Web site: http://www.skippingstones.org
Sports Illustrated for Kids
P.O. Box 60001
Tampa, FL 33660-0001
Toll-free telephone: 800-992-0196
Web site: http://www.sikids.com
P.O. Box 83
Santa Cruz, CA 95063
Toll-free telephone: 800-447-4569
Web site: http://www.stonesoup.com
- Internet Public Library - http://www.ipl.org/div/news
- Refdesk.com - http://www.refdesk.com/paper.html
- Barron's Profiles of American Colleges. Barron's Educational Series, annual.
- Books in Print. Bowker, annual.
- Contemporary Authors. Gale, annual.
- Current Biography. H. W. Wilson, annual.
- Guinness World Records. Bantam Books, annual.
- Readers' Guide to Periodical Literature. H. W. Wilson, annual.
- Subject Guide to Books in Print. Bowker, annual.
- Subject Guide to Children's Books in Print. Bowker, annual.
Web Directories, Search Engines, and Web Guides
- The Alphabet Superhighway - http://www.ash.udel.edu/ash
- Cool Sites for Kids - http://www.ala.org/alsc/children_links.html
- Internet Search Engines for Kids - http://www.ivyjoy.com/rayne/kidssearch.html
- Kids and Teens: Directories - http://dmoz.org/Kids_and_ Teens/Directories
- Kids Pick - http://www.ala.org/kidspick
- KidSpace - http://www.ipl.org/div/ kidspace
- Great Web Sites for Kids - http://www.ala.org/parentspage/greatsites/amazing.html
- Teen Hoopla- http://www.ala.org/ teenhoopla/sitemap.html
- TeenSpace - http://www.ipl.org/div/teen
America's Literacy Directory
Web site: http://www.literacydirectory.org
American Federation for the Blind
11 Penn Plaza, Suite 300
New York, NY 10001
Toll-free telephone: 800-232-5463
Web site: http://www.afb.org
The Barbara Bush Foundation for Family Literacy
1201 15th St. NW, Suite 420
Washington, DC 20005
Web site: http://www.barbarabushfoundation.com
National Literacy Hotline
Toll-free telephone: 800-228-8813
Read Across America
National Education Association
1201 16th St., NW
Washington, DC 20036
Web site: http://www.nea.org/readacross
Reading Is Fundamental Inc.
1825 Connecticut Ave., NW, Suite 400
Washington, DC 20009
Toll-free telephone: 877-RIF-READ
Web site: http://www.rif.org


Green buildings are designed, constructed and operated for the purpose of providing the occupants with a space that is both healthy and productive, while also being energy efficient and sustainable. Unfortunately, current approaches to green building design and construction don’t always meet occupants’ indoor environmental quality (IEQ) needs for “acoustic comfort.”
Acoustic comfort refers to an indoor environment that is conducive to providing speech intelligibility, speech privacy, low distractions and annoyance, and sound quality.
And, according to ongoing research at the Center for the Built Environment (CBE), it is the lowest performing IEQ factor in green buildings. Moreover, in all buildings surveyed, the level of acoustic satisfaction was rated as the lowest performance IEQ factor, and the only negative (dissatisfaction) factor overall.
There is no need, however, to sacrifice good acoustics when selecting products for green buildings. Architects and interior designers do not have to choose between sustainability, design and acoustic needs—they can have all three.
Outlined below are a number of acoustic considerations for green buildings in three market segments: healthcare facilities, commercial offices and educational facilities.
Acoustics are a key element in the IEQ of healthcare facilities because they play an important role in supporting the safety, health and well-being of patients and staff alike.
In general, ambient noise levels in hospitals are high, and have been shown to be a source of annoyance and stress to both patients and staff. They can also interfere with the staff’s ability to work effectively. Because of this, both the FGI 2010 Guidelines and LEED for Healthcare address the issue.
One reason healthcare facilities are so noisy is the predominance of hard, sound-reflecting surfaces that cause speech and activity sounds to persist much too long. When acoustic conditions are characterized by long reverberation, spoken words are perceived to overlap, resulting in reduced speech intelligibility.
To reduce reverberation and noise levels, acoustical ceiling panels should have a noise reduction coefficient (NRC) of 0.70 or greater. (The NRC indicates the average percentage of sound a material absorbs; an NRC of 0.70 means the material absorbs about 70 percent of the sound that strikes it.) They should also meet healthcare standards for washability, mold and microbial resistance, and fire safety. Ceiling panels with these characteristics are ideal for patient rooms, treatment rooms and other spaces that require a balance of cleanliness and quiet.
Ceiling panels with a NRC of 0.95 are recommended for areas that require even higher levels of sound absorption to ensure patient privacy and meet HIPAA regulations. These include open plan spaces such as waiting areas, pharmacies, nurses’ stations and closed plan spaces where walls extend up to the deck above.
Whether for a space with cubicles and teaming areas or private offices and conference rooms, there are acoustic options that also address sustainable needs. For example, a wide range of continuous and wall-to-wall acoustical ceilings are available that not only enhance the acoustic environment, but also contain high recycled content and can be recycled at the end of their service life.
There are also a variety of “free-floating” ceiling treatments including acoustical clouds, canopies and baffles that are ideal for open plenum or exposed structure spaces—a design trend in green buildings that continues to grow.
Unfortunately, this “warehouse look” can often cause acoustical problems due to sound reflecting off the deck, resulting in excessive reverberation. Any large space of this type will usually need some sound-absorbing elements to help control noise and reverberation within it. In addition, if the exposed deck is less than 15 feet high, reflections between open plan cubicles can cause distractions for nearby occupants.
Designed for use in either new construction or retrofit applications, acoustical clouds, canopies and baffles can add sound absorption in open spaces, provide visual interest and make a design statement, all without sacrificing that exposed look.
Available in a myriad of shapes, acoustical ceiling clouds suspended above work areas provide a type of interrupted ceiling plane. As such, they help control both distant reverberations and reflections, reducing occupant annoyance and distractions. Acoustical clouds actually provide greater sound absorption than a continuous ceiling of the same surface area because they absorb sound on both their front and back surfaces. In fact, reverberation time can be reduced nearly 50 percent with only 20 percent coverage.
Acoustical canopies also help reduce reverberation in the space below them, but are much different in size and look compared to acoustical clouds. For example, cloud systems are available in standard sizes up to 14 by 14 feet, while canopies are usually 3 by 3 or 4 by 6 feet in size. Visually, acoustical clouds are flat, while canopies are curved and can be installed as hills or valleys.
Currently, there is no standard credit in the IEQ section of LEED for acoustic performance. However, an innovation credit can be applied for by demonstrating that the acoustics of a building are superior to what would normally be considered typical, thereby improving the quality of the indoor environment. The LEED v4 proposal (in a fifth public comment at the time of this writing) does, however, include a requirement for acoustic performance as part of the IEQ section.
Considering that the primary mode of teaching involves speech and listening, the quality of the acoustic environment in a classroom is crucial. LEED for Schools recognized the unique nature of the design and use of K-12 schools, and was the first of the U.S. Green Building Council (USGBC) rating systems to include acoustics as an integral and important element of IEQ.
To provide classrooms that enhance learning, LEED for Schools includes a minimum acoustical performance prerequisite. To meet it, two requirements must be achieved:
- Classrooms and other core learning spaces must include sufficient sound-absorptive finishes to comply with a maximum reverberation time of 0.60 seconds (classrooms less than 20,000 cubic feet).
- Classrooms and other core learning spaces must meet a maximum background noise level from HVAC systems of 45 decibels A-weighted (dBA).
Compliance with the first requirement is accomplished in one of two ways:
- By confirming that 100 percent of all ceiling areas (excluding lights, diffusers and grilles) are finished with a material that has a NRC of 0.70 or higher.
- By confirming that the total area of acoustical wall panels, ceiling finishes and other sound-absorbent finishes equals or exceeds the total ceiling area of the room (excluding lights, diffusers and grilles). All materials in the calculation must have an NRC of 0.70 or higher.
The proper use of sound-absorbing materials will significantly reduce reverberation, however, the location of acoustic treatments is a vital consideration. In classrooms where there is no fixed position for the teacher and ceiling heights are about 10 feet, the best and most cost-effective option is to place most, if not all, of the sound-absorbing material on the ceiling, in the form of a suspended acoustical ceiling.
If ceiling heights are greater than 12 feet, an increasing amount of sound-absorbing material should be placed on the walls. If there is no possibility for wall treatment, consider placing three-dimensional furnishings such as bookshelves along the walls to ensure sound waves are scattered, thereby reducing the possibility of distant echoes.
Kenneth P. Roy, Ph.D., FASA, is a senior principal research scientist for acoustic technologies for Armstrong Building Products in Lancaster, Pa. He can be reached at firstname.lastname@example.org.


Young children have very short attention spans, which is not surprising given that the optimum study time for an adult is 40 to 45 minutes. So it's quite normal for your students' attention to stray. Also teaching young children is very different to working with adults, you just need to make a few adjustments to how you go about the classes.
You need to think about lots of short activities when you are planning your lessons. At the beginning, this will be very time-consuming as you will need to think through each activity when planning. As time goes by, you will build up a bank of short activities (eg a song, a chant, a nursery rhyme, games such as I spy) that the children are familiar with and that you can introduce when you feel a change is needed. As children get used to your style of teaching, the classroom rules and the types of activity, it will be easier to introduce these short activities into the lesson.
You should also think about pace and variety when you are planning. Some activities should involve whole class focus on the teacher, some should include individual work requiring reflection, some should involve group work and some should include physical movement. The changing focus will also stimulate children, re-focus their attention or calm them down.
You should also insist on having full attention when you are working with or addressing the whole class, for example when telling a story. Children need to understand that when you are talking they should stop what they are doing and listen to you. You could use a signal to indicate when this is necessay, for example clapping your hands.
I'm sure that with time you will get used to teaching children and it will seem less tiring the more you do it.


Behaviour-driven development is an “outside-in” methodology. It starts at the outside by identifying business outcomes, and then drills down into the feature set that will achieve those outcomes. Each feature is captured as a “story”, which defines the scope of the feature along with its acceptance criteria. This article introduces the BDD approach to defining and identifying stories and their acceptance criteria.
Software delivery is about writing software to achieve business outcomes. It sounds obvious, but often political or environmental factors distract us from remembering this. Sometimes software delivery can appear to be about producing optimistic reports to keep senior management happy, or just creating “busy work” to keep people in paid employment, but that’s a topic for another day.
Usually, the business outcomes are too coarse-grained to be used to directly write software (where do you start coding when the outcome is “save 5% of my operating costs”?) so we need to define requirements at some intermediate level in order to get work done.
Behaviour-driven development (BDD) takes the position that you can turn an idea for a requirement into implemented, tested, production-ready code simply and effectively, as long as the requirement is specific enough that everyone knows what’s going on. To do this, we need a way to describe the requirement such that everyone – the business folks, the analyst, the developer and the tester – have a common understanding of the scope of the work. From this they can agree a common definiton of “done”, and we escape the dual gumption traps of “that’s not what I asked for” or “I forgot to tell you about this other thing”.
This, then, is the role of a Story. It has to be a description of a requirement and its business benefit, and a set of criteria by which we all agree that it is “done”. This is a more rigorous definition than in other agile methodologies, where it is variously described as a “promise of a conversation” or a “description of a feature”. (A BDD story can just as easily describe a non-functional requirement, as long as the work can be scoped, estimated and agreed on.)
The structure of a story
BDD provides a structure for a story. This is not mandatory – you can use a different story format and still be doing BDD – but I am presenting it here because it has been proven to work on many projects of all shapes and sizes. At the very least, your story should contain all of the elements described in the template. The story template looks like this:
Title (one line describing the story) Narrative: As a [role] I want [feature] So that [benefit] Acceptance Criteria: (presented as Scenarios) Scenario 1: Title Given [context] And [some more context]... When [event] Then [outcome] And [another outcome]... Scenario 2: ...
Telling the story
A story should be the product of a conversation involving several people. A business analyst talks to a business stakeholder1 about the feature or requirement, and helps them to frame it as a story narrative. Then a tester helps define the scope of the story – in the form of acceptance criteria – by determining which scenarios matter and which are less useful. A technical representitive will provide a ballpark estimate of the amount of work involved in the story, and to propose alternative approaches. Many great ideas for systems come from the people developing them as well as the people who asked for them in the first place.
This will likely be an iterative process. The stakeholder will have an idea of what they want but will usually not know how much work will be involved, or how that work will be allocated. With the help of the technical and testing experts, they will understand the cost/benefit trade-off of each scenario and can make a judgement about whether they want it. Of course this is also balanced up against the other requirements: is it better to cover more edge cases in this story, or to move on to another story?
Sometimes the development team will simply not know enough to be able to make even a ballpark estimate. In this case they may choose to carry out some investigative work, known as a “spike”, in order to understand more about the requirement. (I will cover planning in more detail in a future article.)
The characteristics of a good story
Using the example from the article Introducing BDD, let’s look at the requirements for withdrawing cash from an ATM:
Story: Account Holder withdraws cash As an Account Holder I want to withdraw cash from an ATM So that I can get money when the bank is closed Scenario 1: Account has sufficient funds Given the account balance is \$100 And the card is valid And the machine contains enough money When the Account Holder requests \$20 Then the ATM should dispense \$20 And the account balance should be \$80 And the card should be returned Scenario 2: Account has insufficient funds Given the account balance is \$10 And the card is valid And the machine contains enough money When the Account Holder requests \$20 Then the ATM should not dispense any money And the ATM should say there are insufficient funds And the account balance should be \$20 And the card should be returned Scenario 3: Card has been disabled Given the card is disabled When the Account Holder requests \$20 Then the ATM should retain the card And the ATM should say the card has been retained Scenario 4: The ATM has insufficient funds ...
As you can see, there are a number of scenarios to consider, some related to the account balance, others about the card and yet others about the ATM itself. Let’s dissect the story to determine whether it is any good.
The title should describe an activity
The title of the story, “Account Holder withdraws cash”, describes an activity that the account holder wants to carry out. Until we implement this feature, the account holder won’t be able to withdraw money from the ATM. Once we have delivered it, they will. That gives us an obvious starting point for determining what “done” looks like.
If we had a title like “Account management” or “ATM behaviour”, we would have to look harder to understand when we were finished, and the edges would be a lot more fuzzy. For instance, “account management” might incorporate applying for a loan, and “ATM behaviour” might encompass changing the PIN number on my cash card. The story title should always describe actual behaviour by a user of the system.
The narrative should include a role, a feature and a benefit
The template “As a [role] I want [feature] so that [benefit]“ has a number of advantages. By specifying the role within the narrative, you know who to talk to about the feature. By specifying the benefit, you cause the story writer to consider why they want a feature.
It gets interesting if you find the feature won’t actually deliver the benefit attributed to it. This usually means you have a missing story. There is one story with the current feature, which delivers a different benefit (and is therefore still useful), and a hidden story whereby you will need a different feature to deliver the benefit described.
The example story tells us there is an Account Holder who cares about the feature being delivered, so we know where to start exploring what it should do.
The scenario title should say what’s different
You should be able to line up the scenarios side by side, and describe how they differ using only the title. In our example, we can see that the scenario descriptions say only what’s different between each scenario. You don’t need to say “an account holder withdraws money from an account with insufficient funds and is told they are unable to fulfull the transaction”. It’s obvious from the title whether this is the scenario you care about, compared to the others.
The scenario should be described in terms of Givens, Events and Outcomes
This is the single most powerful behavioural shift I have seen in teams adopting BDD. Simply by getting the business users, the analysts, the testers and the developers to adopt this vocabulary of “given/when/then”, they discover that a world of ambiguity falls away.
Not all scenarios are this simple. Some are best represented as a sequence of events, described as: given [some context] when [I do something] then [this happens] when [I do another thing] then [this new thing happens] and so on. An example is a wizard-style website, where you step through a sequence of screens to build up a complex data model. It is perfectly appropriate to intermingle sequences of events and outcomes, as long as you get into the habit of thinking in these terms.
One interesting emergent behaviour is that the quality of the conversation changes. You will quickly discover that you have missed out an assumed given (“well of course the account is overdrawn”), or forgotten to verify an outcome (“well naturally the account holder gets their card back”). I observed this on one particular project where the lead developer told me he could sense the analysts and developers were talking at cross purposes, but couldn’t see a way to demonstrate this to them. Within a few days of introducing the given/when/then vocabulary, he could see a dramatic improvement in the quality of their interactions.
The givens should define all of, and no more than, the required context
Any additional givens are distracting, which makes it hard for someone looking at the story for the first time – whether from the technical or business side – to understand what they need to know. Similarly any missing givens are really assumptions. If you can get a different outcome from the givens provided, then there must be something missing.
In the example, the first scenario says something about the account balance, the card and the ATM itself. All of these are required to fully define the scenario. In the third scenario, we don’t say anything about the account balance or whether the ATM has any money. This implies that the machine will retain the card whatever the account balance, and whatever the state of the ATM.
The event should describe the feature
The event itself should be very simple, typically only a single call into the production code. As discussed above, some scenarios are more complicated than this, but mostly the scenarios for a story will revolve around a single event. They will differ only in the context (the givens) and the corresponding expected outcomes.
The story should be small enough to fit in an iteration
There are no hard and fast rules about how you do this, as long as you break it down into demonstrable chunks. In general if there are more than about five or six scenarios, a story can probably be broken down by grouping similar scenarios together.
We can’t tell from the ATM example how many more scenarios there are for this story, but I am suspicious that there may be several more. Essentially we have three “moving parts” in this story, namely the account balance, the status of the cash card and the state of the ATM. We could get into more detail with the cash card: what if it is out of date, so I can’t use it to withdraw cash but the ATM still returns it to me? What if the ATM breaks partway through the transaction? What if my account has an overdraft facility?
It might be better to break the story out into several smaller stories:
- Account Holder withdraws cash (assumptions: ATM is working and card is valid)
- Account Holder withdraws cash with invalid card (assumptions: ATM is working)
- Account Holder withdraws cash from flaky ATM (assumptions: card is valid)
Although this may seem artificial, it allows you to demonstrate progress in business terms and gives you more data points to track with. The important thing is always to break the story out along business lines by scenarios (and making the assumptions explicit) rather than along technical lines (e.g. doing the database stuff in this iteration and the GUI stuff in the next iteration). This is so the business can see demonstrable progress on their own terms rather than just taking your word for it.
So how is this different from Use Cases?
There are use cases and there are use cases. I’m a huge fan of the way Alistair Cockburn describes use cases (as opposed to the over-engineered versions I have encountered on RUP-as-waterfall projects). Given that I don’t have much experience on use case-driven projects, I’ll leave it to others to draw the comparisons.
Certainly I agree with his process of starting at the lower precision (of an outcome, or goal) and working towards higher precisions, taking in more exception scenarios as you go. In BDD, this means starting with the business outcome, and working through high level functional areas to drill into specific stories with acceptance criteria.
In reality, it doesn’t matter what your process is to identify and elaborate requirements. It’s fine for you to write requirements documents if that helps you organise your thoughts. It’s not fine, however, to pass those documents along as if they actually encapsulated all your thoughts, because they don’t. Instead, you should put the requirements document, or stack of use cases, to one side and start over defining stories from business outcomes, safe in the knowledge that your hard work has meant that you have all the answers in your head – or at least a good enough understanding to outline the work as you currently see it.
Behaviour-driven development uses a story as the basic unit of functionality, and therefore of delivery. The acceptance criteria are an intrinsic part of the story – in effect they define the scope of its behaviour, and give us a shared definition of “done”. They are also used as the basis for estimation when we come to do our planning.
Most importantly, the stories are the result of conversations between the project stakeholders, business analysts, testers and developers. BDD is as much about the interactions between the various people in the project as it is about the outputs of the development process.
1. Actually it should be the person who actually cares about the feature, so it may equally be an operational, legal or security person depending on the story.


Battle of Caporetto
The Battle of Caporetto (also known as the Twelfth Battle of the Isonzo or the Battle of Karfreit as it was known by the Central Powers), took place from 24 October to 19 November 1917, near the town of Kobarid (now in Slovenia), on the Austro-Italian front of World War I. The battle was named after the Italian name of the town of Kobarid (known as Karfreit in German).
Austro-Hungarian forces, reinforced by German units, were able to break into the Italian front line and rout the Italian army, which had practically no mobile reserves. The battle was a demonstration of the effectiveness of the use of stormtroopers and the infiltration tactics developed in part by Oskar von Hutier. The use of poison gas by the Germans played a key role in the collapse of the Italian Second Army.
||This section needs additional citations for verification. (October 2012)|
The Austrian offensive began at approximately 02:00 on 24 October 1917. Due to the inclement weather that morning, particularly the mist, the Italians were caught by complete surprise. The battle opened with a German artillery barrage, poison gas, and smoke, and was followed by an all-out assault against the Italian lines. The Italians had outdated gas masks, gave no counter fire and had given the Germans all the weather information they needed over their radio. The defensive line of the Italian Second Army was breached between the IV and XXVII Corps almost immediately. The German forces made extensive use of flamethrowers and hand grenades as a part of their infiltration tactics, and were able to tear gaping holes in the Italian line, especially in the Italian strongholds on Mount Matajur and the Kolovrat Range. By the end of the first night, von Below's men had advanced a remarkable 25 km (16 mi). German and Austro-Hungarian attacks from either side of von Below's central column were less effective, however. The Italian Army had been able to repel the majority of these attacks, but the success of von Below's central thrust threw the entire Italian Army into disarray. Forces had to be moved along the Italian front in an attempt to stem von Below's breakout, but this only weakened other points along the line and invited further attacks. At this point, the entire Italian position on the Tagliamento River was under threat.
2nd army commander Luigi Capello was Italy's best general but was bedridden with fever while still retaining command. Realizing his forces were ill-prepared for this attack and were being routed, Capello requested permission to withdraw back to the Tagliamento. He was overruled by Cadorna, however, who believed that the Italian force could regroup and hold out against the attackers. Finally, on 30 October, Cadorna ordered the majority of the Italian force to retreat to the other side of the river. It took the Italians four full days to cross the river, and by this time the German and Austro-Hungarian armies were on their heels. By 2 November, a German division had established a bridgehead on the Tagliamento. About this time, however, the rapid success of the attack caught up with them. The German and Austro-Hungarian supply lines were stretched to breaking point, and as a result, they were not able to launch another concerted attack. Cadorna took advantage of this to retreat further, and by 10 November had established a position on the Piave River.
Failures of German Logistics
Even before the battle, Germany was struggling to feed and supply its armies in the field. Erwin Rommel, who, as a junior officer, won the Pour le Mérite for his exploits in the battle, often bemoaned the demands placed upon his "poorly fed troops". The Allied blockade of the German Empire, which the Kaiserliche Marine had been unable to break, was responsible for food shortages and widespread malnutrition in Germany and the Central Powers in general. When inadequate provisioning was combined with the gruelling night marches preceding the battle of Caporetto (Kobarid), a heavy toll was extracted from the German and Austro-Hungarian forces. Despite these logistical problems, the initial assault was extremely successful. However, as the area controlled by the combined Central Powers forces expanded, an already limited logistical capacity was overstrained. By the time the attack reached the Piave, the soldiers of the Central Powers were running low on supplies and were feeling the physical effects of exhaustion. As the Italians began to counter the pressure put on them by the Central Powers, the German forces lost all momentum and were once again caught up in another round of attrition warfare.
Italian losses were enormous: 10,000 were killed, 30,000 wounded and 265,000 were taken prisoner – morale was so low among the Italian troops, mainly due to Cadorna's harsh disciplinary regime, that most of these surrendered willingly. Furthermore, roughly 3,000 guns, 3,000 machine guns and 2,000 mortars were captured, along with an untold amount of stores and equipment. Rommel, then an Oberleutnant, captured 1,500 men and 43 officers with just 3 riflemen and 2 officers to help. Austro-Hungarian and German forces advanced more than 100 km (62 mi) in the direction of Venice, but they were not able to cross the Piave River. Although to this point the Italians had been left to fight on their own, after Kobarid (Caporetto) they were reinforced by six French infantry divisions and five British infantry divisions as well as sizeable air contingents. However, these troops played no role in stemming the advancing Germans and Austro-Hungarians, because they were deployed on the Mincio River, some 60 miles behind the Piave, as the British and French strategists did not believe the Piave line could be held. The Piave served as a natural barrier where the Italians could establish a new defensive line, which was held during the subsequent Battle of the Piave River and later served as springboard for the Battle of Vittorio Veneto, where the Austro-Hungarian army was finally defeated after four days of stiff resistance.
Luigi Cadorna was forced to resign after the defeat. The defeat alone was not the sole cause, but rather the breaking point for an accumulation of failures, as perceived by the Italian Prime Minister, Vittorio Emanuele Orlando. Throughout much of his command, including at Kobarid (Caporetto), Cadorna was known to have maintained poor relations with the other generals on his staff. By the start of the battle he had sacked 217 generals, 255 colonels and 355 battalion commanders. In addition, he was detested by his troops as being too harsh. He was replaced by Armando Diaz and Pietro Badoglio. He had already been directing the battle 20 miles behind before fleeing another 100 miles to Padua.
This led governments to the realization that fear alone could not adequately motivate a modern army. After the defeat at Caporetto, Italian propaganda offices were established, promising land and social justice to soldiers. Italy also accepted a more cautious military strategy from this point on. General Diaz concentrated his efforts on rebuilding his shattered forces while taking advantage of the national rejuvenation that had been spurred by invasion and defeat.
After this battle, the term "Caporetto" gained a particular resonance in Italy. It is used to denote a terrible defeat – the failed General Strike of 1922 by the socialists was referred to by Mussolini as the "Caporetto of Italian Socialism". Many years after the war, Caporetto was still being used to destroy the credibility of the liberal state.
Popular culture
The Battle of Caporetto has been the subject of a number of books. The Swedish author F.J. Nordstedt (i.e. Christian Braw) wrote about the battle in his novel Caporetto. The bloody aftermath of Caporetto was vividly described by Ernest Hemingway in his novel A Farewell to Arms. Curzio Malaparte wrote an excoriation of the battle in his first book, Viva Caporetto, published in 1921. It was censored by the state and suppressed; it was finally published in 1980.
- Tucker, Spencer C. (11 November 2010). Battles That Changed History: An Encyclopedia of World Conflict. United States: ABC-CLIO. p. 430. ISBN 978-1-59884-429-0. Retrieved 16 September 2012.
- Tucker, Spencer C.; Roberts, Priscilla Mary (25 October 2005). World War I: A Student Encyclopedia. United States: ABC-CLIO. p. 431. ISBN 1-85109-879-8. Retrieved 5 August 2012. "By 10 November Italian losses were 10,000 dead, 30,000 wounded, and 265,000 prisoners (about 350,000 stragglers from the Second Army did manage to reach the Piave line). The army had also lost 3,152 artillery pieces of a preoffensive total of 6,918. An additional 1,712 heavy trench mortars and 3,000 machine guns had been captured or abandoned in the retreat, along with vast amounts of other military equipment, especially as the rapid withdrawal had prevented the removal of heavy weapons and equipment across the Isonzo River. In contrast, the attackers had sustained about 70,000 casualties."
- Seth, Ronald (1965). Caporetto: The Scapegoat Battle. Macdonald. p. 147
- Stearns, Peter; Langer, William (2001). The Encyclopedia of World History (6th ed.). Houghton Mifflin Harcourt. p. 669. ISBN 0-395-65237-5.
- Dupuy & Dupuy (1970), p. 971
- Geoffrey Regan, More Military Blunders, page 161
- Macksey, Kenneth (1997). Rommel: Battles and Campaigns. Da Capo Press. p. 224. ISBN 0-306-80786-6.
- Simkins, Peter; Jukes, Geoffrey; Hickey, Michael (2003). The First World War. Osprey Publishing. p. 352. ISBN 1-84176-738-7.
- Townley, Edward (2002). Collier, Martin, ed. Mussolini and Italy. Heinemann. p. 16. ISBN 0-435-32725-9.
- Geoffrey Regan, More Military Blunders, page 160
- Morselli, Mario (2001). Caporetto, 1917: Victory Or Defeat?. Routledge. p. 133. ISBN 0-7146-5073-0.
Further reading
- Connelly, O. On War and Leadership: The Words of Combat Commanders from Frederick the Great to Norman Schwarzkopf, 2002 ISBN 0-691-03186-X
- Dupuy R. E., &, Dupuy, T. N., The Encyclopedia of Military History, (revised edition), Jane's Publishing Company, 1970, SBN 356 02998 0
- Morselli, M. Caporetto 1917: Victory or Defeat?, 2001 ISBN 0-7146-5073-0
- Reuth, R. G. Rommel: The End of a Legend, 2005 ISBN 1-904950-20-5
- Seth, Ronald: Caporetto: The Scapegoat Battle. Macdonald, 1965
- Cavallaro, G. V. Futility Ending in Disaster. Xlibris, 2009
|Wikimedia Commons has media related to: Battle of Caporetto|
- Walks of Peace in the Soea Region Foundation: The Battles of the Isonzo, 1915–17
- Pro Hereditate: The Isonzo Front
- (Italian) La Grande Guerra: Novant'anni fa la Battaglia di Caporetto
- The Battle of Caporetto, 1917


The Racial Geography of the Federal Death Penalty
Scholars have devoted substantial attention to both the overrepresentation of black defendants on federal death row and the disproportionate number of federal defendants charged capitally for the murder of white victims. This attention has not explained (much less resolved) these disquieting racial disparities. Little research has addressed the unusual geography of the federal death penalty, in which a small number of jurisdictions are responsible for the vast majority of federal death sentences. By addressing the unique geography, we identify a possible explanation for the racial distortions in the federal death penalty: that federal death sentences are sought disproportionately where the expansion of the venire from the county to the district level has a dramatic demographic impact on the racial make-up of the jury. This inquiry demonstrates that the conversation concerning who should make up the jury of twelve neighbors and peers - a discussion begun well before the founding of our Constitution - continues to have relevance today. This Article documents the historical and racial relationships between place and the ability to seat an impartial jury. We then discuss the unique impact demographic shifts in the jury pool have on death penalty decision making. Finally, we propose three possible solutions: (1) a simple, democracyenhancing fix through a return to the historical conception of the county as the place of vicinage in federal capital trials; (2) a Batson-type three-step process for rooting out the influence of race on the decision to prosecute federally; and/or (3) voluntary measures by the Attorney General to mask demographic and location identifiers when deciding whether to provide federal death-authorization. We explain why a return to county-level jury pools in federal capital cases (whether through statutory construction, legislative change, or through the authority of a fair-minded Attorney General) prospectively limits the impact of race on the operation of the federal death penalty, without establishing the intractability of the federal death penalty as a whole. Finally, we observe that any effort to study the federal death penalty cannot merely address those federal cases in which the Attorney General has considered whether to approve an effort to seek the death penalty, but must also include an assessment of the cases prosecuted in state court that could be prosecuted federally and the prosecutorial decision concerning when and whether to prosecute in federal court.
Robert J. Smith and G. Ben Cohen. "The Racial Geography of the Federal Death Penalty" Washington Law Review (2010).


Two well-preserved sections of the Antonine Wall are located at Hillfoot Cemetery, about a mile from the Roman bath at Bearsden, located in in southwestern Scotland near Glasgow. The exposed sections, within easy walking distance of each other, are stone footings which lay at the base of the Wall. They provide vivid examples of the massive size and careful construction methods used in the Wall.
(Figs.1,2: Exposed footings of Antonine Wall in Hillfoot (Photos: Athena Review).]
These portions of the ancient wall were exposed in 1903 and 1922, during expansion of the cemetery. The Antonine Wall at this location was originally 4.3 meters wide, but portions found at Hillfoot were later widened to 5 meters. Each of the exposed basal sections has outside rows of large dressed curbstones and a drainage system.
This drainage culvert crosses a basal section of the Antonine Wall at Hillfoot Cemetery in Bearsden, near Glasgow, Scotland. The Wall was built and maintained between 142 and 165 AD.
[Fig.3: Drainage culvert in Antonine Wall at Hillfoot (Photo: Athena Review).]
[References: Keppie, Lawrence. Scotland's Roman Remains. Glasgow, 1986, 1990.]
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