The fertilizing ability of spermatozoa is inhibited by certain substances present in the seminal fluid. Most of these antifertility factors are proteinaceous in nature and differ in their physical characteristics. They inhibit fertilization by inhibiting either motility, capacitation, acrosome reaction or penetration of the ovum investments by the spermatozoa. This review describes and discusses the properties of these factors and their possible role, individually and collectively, in the regulation of fertility.

This white paper aims to identify an open problem in 'Quantum Physics and the Nature of Reality' -namely whether quantum theory and special relativity are formally compatible-, to indicate what the underlying issues are, and put forward ideas about how the problem might be addressed.

The relativistic three-particle systems are studied within the framework of Relativistic Schrödinger Theory, with emphasis on the determination of the energy functional for the stationary bound states. The phenomenon of entanglement shows up here in form of the exchange energy which is a significant part of the relativistic field energy. The electromagnetic interactions become unified with the exchange interactions into a relativistic U gauge theory, which has the Hartree–Fock equations as its non-relativistic limit. This yields a general framework for treating (...) entangled states of relativistic many-particle systems, e.g., the N-electron atoms. (shrink)

Science education is most efficacious and enduring when undertaken within a philosophical framework akin to that of science, itself. This entails recognition that, above all, science is a mode of rational inquiry pursued by those who are curious about the natural world and motivated to seek rational answers to personally meaningful questions. The key to successful science instruction lies in fostering a student' 's self-motivation and productively channeling his innate curiosity. To do this a science educator must convey to students (...) an accurate and sympathetic impression of the importance of science to their cultural development; help students develop an ability to evaluate information critically and arrive at logical conclusions; provide students opportunities to engage in creative, personally meaningful scientific research. (shrink)

To start thinking about the Gregory Skovoroda phenomenon and its promising interconnectedness with the culture of the hoped for, we want from a series of somewhat unexpected considerations and parallels that we hope will reflect both the subject matter itself and the prospects for the future. It is well-known that Kharkov entered the modern history of Ukraine as the “second capital of our statehood, as the capital of constructivist modern Ukraine of the 1920s, which, and this is often forgotten, favoring (...) Kyiv and the West of Ukraine, became the birthplace and epicenter of a powerful national-cultural movement Ukrainianization. It was in Kharkov that a unique aesthetic phenomenon was born and flourished - literature and art of the firing Renaissance. (shrink)

After two weeks in La Barca, a small dirt-lined Mexican town known for its delicious tacos and endemic salmonellosis, it seemed I was serving a prison sentence rather than my sixth-semester surgery rotation. It was almost 11:00 on another insufferably humid day and I was in the operating room. I struggled to maintain my steady contorted position as I held the patient’s abdominal cavity open with surgical retractors for the chief surgeon and the resident. I had been plagued with a (...) wonderful bout of gastroenteritis since my arrival in La Barca, so my knees buckled and my attention peaked with every wave of abdominal false alarms. My peripheral vision had been obliterated thanks to the …. (shrink)

There are two fundamentally different approaches to innovation: incremental and radical. In Economics as Anatomy, G.M. Peter Swann argues that economics as a discipline needs both perspectives in order to create the maximum beneficial effect for the economy. Chapters explore how and why mainstream economics is very good at incremental innovation but seems uncomfortable with radical innovation. Swann argues that economics should follow the example of many other disciplines, transitioning from one field to a range of semi-autonomous sub-disciplines. In this (...) book, he compares the missing link in empirical economics to being the economic equivalent of anatomy, the basis of medical discourse. Working as a sequel to Swann's Putting Econometrics in its Place, this book will be a vital resource to those who are discontent with the state of mainstream economics, especially those actively seeking to promote change in the discipline. Students wishing to see progress in the teaching of economics will also benefit from this timely book. (shrink)