Do Bumblebees Forage Optimally, and Does It Matter?

Foraging behavior of bumblebees has been in the past analyzedfrom two major perspectives. On the one hand, behavioral mechanismshave been studied to learn more about the animal. On the otherextreme, the animal has been used incidentally to examine optimalforaging theory (O.F.T.). Major problems have arisen when theorydesigned to answer evolutionary questions was used to determineproximal mechanisms. While O.F.T. could be highly useful inmaking predictions to point out useful problems, the bottleneckto our understanding at the present resides in the lack of experimentsthat test alternative hypotheses. Whether or not a bumblebee worker's foraging behavior is adaptive(enhances fitness), however, or is optimal (maximizes fitness)cannot yet be resolved by observations or experimentation onindividual bees. However, calculations can show the potentialenergy costs and payoffs of alternative potential foraging behaviors.Rapid progress could be made by examining the mechanisms offoraging behavior that act to enhance foraging returns, withoutworrying about whether or not the behavior is "optimal."     

If You’ve Got It,Flaunt It: Humans Flaunt Attractive Partners to Enhance Their Status and Desirability

Mating decisions are influenced by conspecifics’ mate choices in many species including humans. Recent research has shown that women are more attracted to men with attractive putative partners than those with less attractive partners. We integrate these findings with traditional accounts of social signaling and test five hypotheses derived from it. In our study, 64 men and 75 women were paired with attractive and unattractive opposite-sex putative partners and asked whether they would prefer to give surveys to peers or to older adults. Consistent with predictions, both men and women wanted to show off (flaunt) attractive partners by administering surveys to peers and both men and women wanted to hide (conceal) unattractive partners from peers by administering surveys to older adults. These decisions were mediated by how participants expected others to evaluate their status and desirability when they administered the surveys, consistent with partners serving a social signaling function in humans.     

Is an Idea Different from Cake: Can You Have It and Eat It,Too? A Violation of Permanence in Information Consumption

One of the basic features of information is permanence. This feature states that the consumption of information by one consumer does not affect the availability of that information to other consumers. We present examples in two studies indicating that both laymen and experts of information exchange may be motivated to make choices that violate the permanence feature in accepting (Study 1) and offering (Study 2) information. When they possess, but have not yet consumed information, people may suffer from the appearance of wastefulness. This apparent wastefulness may provide a potential explanation for the observed violation of the permanence feature. Our findings indicate that, as the material age evolves into the information age, information-exchange behavior has not evolved significantly away from material-exchange behavior.     

Lipid Phase Fatty Acid Flip-Flop, Is It Fast Enough for Cellular Transport?

The mechanism by which fatty acids are transported across cell membranes is controversial. The essence of the controversy is whether transport requires membrane protein mediation or whether the membrane's lipid phase provides a pathway so rapid that a protein is not needed. This review focuses on the mechanisms of fatty acid transport across lipid bilayer membranes. These results for lipid membranes are used to help evaluate transport across cell membranes. Within the context of this analysis, a lipid phase mediated process is consistent with results for the transport of fatty acids across erythrocytes but provides a less adequate explanation for fatty acid transport across more complex cells. Received: 16 June 1999/Revised: 21 January 2000     

Is the Naturalistic Fallacy Dead (and If So,Ought It Be?)

Much of modern moral philosophy argued that there are is's in this world, and there are oughts, but that the two are entirely independent of one another. What this meant was that morality had nothing to do with man's biological nature, and could not be derived from it. Any such attempt was considered to be a categorical mistake, and plain foolish. Most philosophers still believe this, but a growing group of neo-naturalist thinkers are now challenging their assumptions. Here I consider the latest work of one of them, Patricia Churchland, on what neurobiology teaches us about morality, and ask whether her challenge means that the naturalistic fallacy, as it is known, should be laid to rest. I argue that while there may be no such thing as a human trait divorced from human biology, this does not necessarily mean that our natures produce constraints that are relevant to specific moral dilemmas.     

Forest Canopy Stratification-Is It Useful?

It has long been recognized that the forest canopy has a complex structure that is significant for environmental interactions, regeneration, growth, and biotic habitat. Not only is the structure variously complex, but also there are many ways to conceptualize that complexity. Yet the persistent theme when considering the structure of canopies continues to be that of stratification: whether structural units are arranged in layers above the ground. We examined the use of the terms "stratification," "layering," and others in connection with canopy structure and found they had various meanings (often only implied) that were difficult to reconcile and to measure. We applied the definitions to the structure of a single, well-studied canopy located in Virginia, U.S.A., and found they failed to define consistently and clearly the presence, number, or location of strata. Additionally, we found the concept had limitations related to scale dependence, point of reference, and spatial averaging. Thus, asserting that a forest is stratified or naming the number of layers generally provided no guide to its structure. We propose alternative ways of conceptualizing and studying the forest canopy that avoid most of the problems associated with stratification. Among these are direct measurement and mapping of structural and environmental variables that have clear potential connections with canopy functions and viewing the distribution of structures or environmental conditions within the canopy as ecological gradients.     

Is the chimpanzee, Pan troglodytes, an endangered species? It depends on what “endangered” means

I review information on the status in the wild of the robust chimpanzee, Pan troglodytes, and consider whether this evidence is consistent with the designation of P. troglodytes as Endangered in the International Union for the Conservation of Nature and Natural Resources (IUCN) Red List, and with public statements to the effect that great apes as a whole will be extinct within a few decades. Chimpanzees remain widespread in tropical Africa, occurring in a variety of forested habitats. Estimates of total surviving numbers have increased from about 200,000 in the 1980s to a maximum of almost 300,000 in 2003. However, this apparent increase comes about from new survey data, rather than representing a measured increase in actual population numbers. Infectious disease decimated several chimpanzee populations during the 1990s, and data from parts of Gabon, extrapolated to that country as a whole, suggest a major decline in great ape populations caused by disease and hunting. However, accurate data on population numbers are absent for the majority of wild chimpanzee populations. I found reports of the presence of Pan troglodytes in at least 51 national parks in at least 19 countries; some of these parks have been established very recently. Chimpanzees also occur in many non-park conservation areas. A set of large, well-protected parks could safeguard chimpanzees for the foreseeable future. Although many African parks do not function well at present, mechanisms to improve their function are understood and available. By a strict application of IUCN threat criteria, P. troglodytes can be considered Endangered, based on estimated rates of past decline and on the species long generation time. Relatively speaking, however, P. troglodytes is less endangered than are orangutans or gorillas, and the species is unlikely to go extinct by the year 2100, especially if existing conservation measures improve. The IUCN threat-rating system has become overly complex; the system can produce results that do not accord with common sense and these results must therefore be interpreted with care.     

Does It Sink or Float?

ABSTRACT

This activity is designed to teach prekindergarten to second grade students about the concept of sink or float through an inquiry activity. Students will use familiar objects to predict and test the properties of sink and float. Background information is offered to teachers to assist them with this activity. This lesson begins with an engaging story, Who Sank the Boat? by Pamela Allen.     

PKCβ Phosphorylates PI3Kγ to Activate It and Release It from GPCR Control

All class I phosphoinositide 3-kinases (PI3Ks) associate tightly with regulatory subunits through interactions that have been thought to be constitutive. PI3Kγ is key to the regulation of immune cell responses activated by G protein-coupled receptors (GPCRs). Remarkably we find that PKCβ phosphorylates Ser582 in the helical domain of the PI3Kγ catalytic subunit p110γ in response to clustering of the high-affinity IgE receptor (FcεRI) and/or store-operated Ca²⁺- influx in mast cells. Phosphorylation of p110γ correlates with the release of the p84 PI3Kγ adapter subunit from the p84-p110γ complex. Ser582 phospho-mimicking mutants show increased p110γ activity and a reduced binding to the p84 adapter subunit. As functional p84-p110γ is key to GPCR-mediated p110γ signaling, this suggests that PKCβ-mediated p110γ phosphorylation disconnects PI3Kγ from its canonical inputs from trimeric G proteins, and enables p110γ to operate downstream of Ca²⁺ and PKCβ. Hydrogen deuterium exchange mass spectrometry shows that the p84 adaptor subunit interacts with the p110γ helical domain, and reveals an unexpected mechanism of PI3Kγ regulation. Our data show that the interaction of p110γ with its adapter subunit is vulnerable to phosphorylation, and outline a novel level of PI3K control.     

It Is Tough and Tiring but It Works—Children’s Experiences of Undergoing Radiotherapy

Approximately 300 children ages 0 to 18 are diagnosed with cancer in Sweden every year, and 80 to 90 of them undergo radiotherapy treatment. The aim was to describe children’s experiences of preparing for and undergoing radiotherapy, and furthermore to describe children’s suggestions for improvement. Thirteen children between the ages of 5 and 15 with various cancer diagnoses were interviewed. Data was analyzed using qualitative content analysis. The findings revealed five categories: positive and negative experiences with hospital stays and practical arrangements; age-appropriate information, communication, and guidance to various degrees; struggle with emotions; use of distraction and other suitable coping strategies; and children’s suggestions for improvement during radiotherapy. An overarching theme emerged: “It is tough and tiring but it works”. Some key areas were: explanatory visits, the need for information and communication, being afraid, discomfort and suffering, the need for media distraction, dealing with emotions, and the need for support. A systematic, family-centered preparation program could possible help families prepare and individualized distraction during radiotherapy could contribute to reducing distress. Further studies with interventions could clarify successful programs.     

Birds Do It. Bees Do It. So Why Not Single Women and Lesbians?

Infertile couples have come to take assisted reproductive technologies (ART) for granted. An increasing number of single women and lesbian couples also desire to have children and turn to ART, especially donor insemination, to fulfill this desire. While most married couples find that access to ART is limited primarily by the ability to pay, for single women and lesbian couples, the story may be much different. In the United States, they may find that doctors and infertility clinics view their desires as immoral and refuse to accept them as patients, although other doctors and clinics readily accept them. In most other countries, however, it is against the law for single women and lesbian couples to make use of ART, including donor insemination.
In this paper I will argue that marital status and sexual orientation should not serve as a barrier to accessing the world of reproductive medicine. I will base this conclusion on two arguments. First, that justice requires that we treat like cases alike. Just as we would not accept or reject patients for cardiac rehabilitation programs based on factors such as a history of poor eating habits, so too we should not look at nonmedical factors such as marital status when deciding whether to treat infertility. For the second justification for the conclusion of equal access to ART, I will examine the concept of the family. I will argue that it is morally acceptable for single women and lesbian couples to have children and to head families.