Bone health is critical for a healthy daily life. Bone metabolism is highly dynamic, and the diseases associated with it, such as osteoporosis, are complex. The mechanisms that affect bone loss with aging are the same as those that limit long term space flight such as a manned mission to Mars. Join Dr. Ledet and get the latest in bone metabolism. Take a look at the unintended consequences of some recent therapies that try to address bone loss: they may actually increase risk of fracture. Gain insight into both the challenges and opportunities in current therapeutic approaches for reducing bone loss to keep aging individuals active and current countermeasures for astronauts to make long term spaceflight feasible.

How do you keep your hinges moving? The understanding of how joints function and how they degenerate has evolved dramatically in recent years. Both genetics and environment play a significant role in degenerative joint disease. For patients with osteoarthritis, new therapies can slow the progression of the disease and lessen symptoms. Total joint replacement is still the gold standard, while innovations in implant design, materials, and surgical techniques have improved outcomes and longevity. Get news you can use as we discuss the state-of-the art understanding of osteoarthritis and the most current treatment options.

The spine is a highly complex system that is vulnerable to injury and painful degeneration. Low back and neck pain are the leading causes of disability world-wide. While the reasons for this degeneration remain unclear we do know genetics, nutrition, and biomechanical factors are in the mix. New non-surgical treatments and innovative surgical techniques show promise for arresting the progression of the disease and eliminating symptoms. Dr. Ledet will review the mechanisms underlying low back and neck pain and you’ll learn about new strategies and new technologies for treatment.

“Smart” implants not only perform their typical therapeutic function, but also provide important diagnostic information from within the body that could not be obtained any other way. Data are communicated wirelessly from the implant to an external reader using implantable sensor technology allowing for personalized care after orthopaedic surgery. Learn the history of smart orthopaedic implants, review state-of-the-art wireless implantable sensor technology and find out how it enhances the success of smart implants.


Situated atop a basalt promontory along the seashore just north of Belfast, Carrickfergus is the largest and best-preserved Norman castle in Ireland — and is also a splendid example of medieval-era military engineering. Its design reflects a well-conceived defensive system that incorporates such characteristic features as inner and outer wards, a keep, an elaborate gatehouse with portcullis, a postern gate, crenellated curtain walls, towers, and crossbow loops.
      In this lecture, we will explore the medieval castle as a technological system, developed and implemented within the broader social, political, and economic contexts of the Middle Ages. We will focus, in particular, on the design and historical development of Carrickfergus Castle, constructed in three distinct phases between the 12th and 14th centuries — with each phase representing a substantial improvement in the effectiveness of its defensive works. We will compare Carrickfergus with other examples of medieval fortifications; and we will conclude with a discussion of the castle as a stimulus for Western scientific and technological development in the medieval era.

During the 14th century, gunpowder weapons were gradually introduced into European warfare, though their military effectiveness was initially limited by technological shortcomings. By the late 15th century, however, longstanding challenges in metallurgy and gunpowder chemistry had been overcome, and gunpowder artillery came of age. In 1494, when King Charles VIII of France led his army into Italy to secure his claim to the Kingdom of Naples, he included powerful mobile cannons in his siege train for the first time in history. At the siege of Mordano, Charles’ artillery breached the city walls in less than three hours — demonstrating that, practically overnight, gunpowder weapons had rendered medieval-style fortifications obsolete.
      In short order, the engineers of the Italian Renaissance responded with a suitably well-reasoned countermeasure — a radically new fortification system called trace italienne. This system replaced the tall, thin stone walls of the medieval castle with low, thick, angular earthworks, which provided far greater resistance to artillery impacts. In contrast with the ad hoc character of medieval fortifications, trace italienne was a true engineered system — in the modern sense. Its curtain walls, bastions, ditches, outworks, and gun emplacements were scientifically designed to provide an integrated, multi-layered defensive network.
      Having demonstrated its effectiveness, the trace italienne system quickly spread across Europe and was applied to the defenses of hundreds of cities. One of the finest surviving examples can be found in the well-preserved city walls of Londonderry, Northern Ireland, less than two hours’ drive from Belfast.
      In this lecture, we will examine the historical development and characteristic features of trace italienne fortifications, using the defenses of Londonderry as a representative example. Along the way, we will gain an appreciation for the ingenuity of this engineered system as an influential yet largely unappreciated product of the Italian Renaissance. We will also survey subsequent refinements of the trace italienne system and their enduring influence on the fabric of many European cities today.

Our itinerary for the Bright Horizons 38 cruise will provide us with opportunities to see a wide variety of interesting bridge structures — from the medieval stone arch bridge at Glanworth Castle in Cork to the dramatically undulating Anaconda Bridge in Amsterdam to Santiago Calatrava’s harp-inspired Samuel Becket Bridge in Dublin. During this lecture, we will examine the great bridges of Bright Horizons 38 from three distinctly different perspectives:

  • THE ENGINEERING PERSPECTIVE: Because most bridges are designed for the primary purpose of carrying loads efficiently, the physical configuration of a bridge typically reflects the scientific principles underlying its design.
  • THE HISTORICAL PERSPECTIVE: Every bridge is a human achievement that reflects its historical context, including the technological resources — materials, scientific tools, computational methods, and construction technologies — available at the time.
  • THE CULTURAL PERSPECTIVE: A bridge is a cultural artifact that often mirrors the norms, priorities, and aspirations of the society from which it emerged.

Through this analysis and discussion, we will be better equipped to see and understand the many fascinating structures we will encounter during our cruise.

Designed in 1881 and completed in 1890, the Firth of Forth Bridge provided a vital link in the North British Railway line from Edinburgh to Dundee. In designing this structure, engineers John Fowler and Benjamin Baker had to overcome enormous technical and non-technical challenges. From the engineering perspective, the bridge would need to carry heavy trains across an 8,000-foot expanse of water, its foundations bearing upon soil of extremely poor quality. From a non-technical perspective, the design would need to overcome the severe loss of public confidence caused by the catastrophic failure of the nearby Firth of Tay Bridge just two years earlier.
      Fowler and Baker responded to these challenges with an extraordinary design — a monumental cantilever truss that (1) incorporated the world’s two longest spans, (2) was the world’s first major structure constructed entirely of steel, and (3) has been appropriately characterized as the world’s safest (and most expensive) bridge. Today, the Firth of Forth Bridge is a UNESCO World Heritage Site, a civil engineering icon, and a widely recognized symbol of Scotland.
      This lecture will address the design, construction, and legacy of the Firth of Forth Bridge. Following an overview of the historical events that profoundly influenced Fowler and Baker’s design, we will focus on key aspects of the design itself — in particular, its cantilever configuration, the use of steel as its principal construction material, and the use of pneumatic caisson foundations. We will consider the engineers’ ingenious public relations campaign, which effectively overcame widespread public concerns about the safety of the bridge. We will explore the methods used to construct this monumental structure. And we will consider its surprising influence on the future course of bridge engineering far beyond the United Kingdom.


Few of us are likely to die of smallpox, scarlet fever or malaria, to be picked off by a predator, or to starve because locust have eaten our crops. Instead, we suffer from Westernized disease, which is to say that we live well enough and long enough to suffer the consequences of diseases of lifestyle, where our bodies slowly fall apart over time. As a critical point, most diseases of Westernized lifestyle can be caused or worsened by stress, and most of us will have the profound Westernized luxury of dying someday of a stress-related disease.
      In this talk, Dr. Sapolsky approaches the basic concept in the field of stress and health: if you turn on the stress-response for three minutes because a predator is chasing you, everything that is happening then in your body is brilliantly adaptive for surviving that crisis, but if you turn on that same stress-response for thirty years worrying about mortgages, traffic jams and bosses, it damages your body.
      Dr. Sapolsky first reviews how the acute stress-response saves your life if you are being stressed like a normal mammal. He then considers how chronic psychosocial stress increases the risk and severity of a wide range of metabolic, cardiovascular, gastrointestinal, inflammatory and psychiatric diseases. He then considers a key final point — why are some bodies and some psyches better at dealing with stress than others? In doing so, he presents the basic principles of stress management.

Major depression has been termed “malignant sadness,” and the lay public often has a poor sense of its causes, and shrouds it in stigma. Which is too bad, since it is a disease of epidemic worldwide proportion. In this talk, Dr. Sapolsky emphasizes, above all else, that depression is not a self-indulgent unwillingness to show the gumption that everyone else does in pulling themselves out of a funk. Instead, it is indeed a disease, as real of a biological disorder as is diabetes.
      After introducing the major symptoms of depression, Dr. Sapolsky considers the biology of depression. What chemical messengers in the brain — neurotransmitters — are abnormal in the disease and how do antidepressant drugs and other treatments affect them? What changes in the structure and activity of different parts of the brain occur in depression? What do hormones and genes have to do with depression risk?
      What this review will show is that amid this state-of-the-art knowledge, this purely biological perspective does not give a ton of insight. Dr. Sapolsky then adds in the psychological features of depression. What is it that makes psychological stress stressful? What does learning that you are helpless do to the function of the brain? How does loss and trauma early in life make you more at risk for depression forever after?
      What this produces is a synthesis — depression is a disorder of vulnerability, where genes and/or early life adversity make for a brain that is less able to regain its emotional equilibrium after psychological stress.

While we humans are ultimately just another species of primate, we present a major paradox. On one hand, we are the most miserably violent species earth has ever seen, capable of damaging each other in extraordinary ways. But at the same time, we are the most cooperative, altruistic and compassionate species on the planet. How can we understand the biology of our best and worst behaviors, and all those that float ambiguously in between?
      In this talk, Dr. Sapolsky paints on a broad canvas. One of those behaviors occur — good, bad, in between — and we ask, Why did that person do that? To understand that act, we must consider what went on in that person’s brain one second before the act. However, one must also consider the environmental stimuli seconds to minutes before which triggered those neurons into action. As well as the hormones which hours to days before change the sensitivity of the brain to those stimuli. But one must also factor in the changes in the brain — “neural plasticity” — that occurred in the previous months. And then it is back to seeing how events in adolescence, childhood and fetal life shaped that brain into being what it was at that moment of acting. But one must go even further back to what the person’s genes have to do with the behavior. And remarkably, even further back — how did the culture that one’s ancestors created centuries ago (and the ecological forces that shaped those cultures) influence how that person was raised and what they value? And finally, how did evolutionary forces shape the behavior of our species?
      What comes out of this survey is a demonstration that, as biological organisms, humans have far less (if any) free will than most people are comfortable with. Dr. Sapolsky will lead a discussion of how understanding the biology of behavior challenges many of our notions of volition, agency and responsibility.

Few diseases, psychiatric or otherwise, are as puzzling and devastating to its sufferers and their loved ones as is schizophrenia. In this overview, Dr. Sapolsky considers the many misconceptions about schizophrenia before moving to what it is — a disease where thought is disordered in some characteristic ways, filled with delusions and hallucinations, social withdrawal and flattened emotions.
      In doing so, Dr. Sapolsky tackles what is really the core challenge of understanding schizophrenia — how can one do objective science about a disease whose primary symptom is thinking differently from what everyone else considers to be normal? The challenge is that “thinking differently” can describe a tragic disease, or brilliance that will change the world, or describe contrarians who challenge tyrants.
      An answer to this is to focus on the objective, consistent biological features that are found in the disease across cultures. In doing so, Dr. Sapolsky will review the biochemical and structural abnormalities in the brains of people with schizophrenia, and what genes, prenatal environment and adolescent stress have to do with the disease.
      At the end, Dr. Sapolsky considers a puzzling question — how did schizophrenia evolve? — and explores a provocative, controversial theory that has run through the anthropological literature for close to a century.

You don’t need to get up on a soapbox to convince people that, ranging from a mugging to a mushroom cloud, the threat of violence menaces our lives. Dr. Sapolsky considers the biology of violence, dealing with a single fact that makes this one of the most complicated subjects in behavioral biology — we don’t hate violence. In fact, at times, we love it — we pay money to watch it, barely restrain ourselves from jumping in, glorify, and reward our experts at it. What we hate is violence in the wrong context, a very different proposition.
      Delve into the biology of violence, beginning with what happens in the brain a second before a person commits a violent act, to considering factors influencing that neurobiology, stretching all the way back to the selective pressures that mediated the evolution of violence over the course of millions of years. Along the way, you’ll find some good news. For example, while some very visceral parts of our brains are prone to divide the world into Us and Them (and to not much like the latter), we can be manipulated into changing Us/Them dichotomies very rapidly. And how a hormone renowned for its ability to promote violence, namely testosterone, actually has far less to do with it than typically thought. We’ll see how evolutionary biology and game theory help explain circumstances where cooperation arises in the most unlikely places. Join the discussion and make more sense of violence and aggression.


Within a hundred years, we’ll have colonists on the moon and possibly Mars. But more important, we’ll have habitats orbiting Earth. We’ll finally understand biology and be able to lengthen lives, prevent disease, and have designer babies. But the most important thing we’ll do is to invent our successors.

Researchers are hot on the trail of biology beyond Earth, and there are good reasons to suspect that we’ll find it within one or two decades. Some think we’ll first discover microbes under the sands of Mars or the ice of a jovian moon. But we might find evidence for intelligent aliens first. How are we looking, and what would such a discovery portend for our descendants?

Forget the anthropomorphic gray guys with the big eyes and small stature. What might we really find among the clotted star fields of space? And why does Hollywood demonstrate so little imagination when it comes to portraying extraterrestrials?

UFOs, crop circles, and unsavory abductions. One-third of the populace is convinced that Earth is being visited (and the government is probably covering up the news). The testimony of astronauts, military pilots, and credible members of the public seems to back this claim. Or does it? Is there really proof that we’re being visited?

It’s tough to predict the weather two weeks from now, but physicists and astronomers are able to tell you what’s going to happen trillions of years into the future. What happens to Earth when the Sun dies, and is there any way for our successors to keep human culture alive in a universe that’s destined to spend eternity in infinite gloom?