The purpose of this article is to show how the concept of stakeholders in an organization can be used to understand the tasks of the board of directors. The authors argue that a volunteeristic approach to questions of corporate governance which focuses on effective director behavior is preferable to structural change via legislation.

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Parasites can be used as unique markers to investigate host evolutionary history, independent of host data. Here we show that modern human head lice, Pediculus humanus, are composed of two ancient lineages, whose origin predates modern Homo sapiens by an order of magnitude (ca. 1.18 million years). One of the two louse lineages has a worldwide distribution and appears to have undergone a population bottleneck ca. 100,000 years ago along with its modern H. sapiens host. Phylogenetic and population genetic data suggest that the other lineage, found only in the New World, has remained isolated from the worldwide lineage for the last 1.18 million years. The ancient divergence between these two lice is contemporaneous with splits among early species of Homo, and cospeciation analyses suggest that the two louse lineages codiverged with a now extinct species of Homo and the lineage leading to modern H. sapiens. If these lice indeed codiverged with their hosts ca. 1.18 million years ago, then a recent host switch from an archaic species of Homo to modern H. sapiens is required to explain the occurrence of both lineages on modern H. sapiens. Such a host switch would require direct physical contact between modern and archaic forms of Homo.

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Background: The parasitic sucking lice of primates are known to have undergone at least 25 million years of coevolution with their hosts. For example, chimpanzee lice and human head/body lice last shared a common ancestor roughly six million years ago, a divergence that is contemporaneous with their hosts. In an assemblage where lice are often highly host specific, humans host two different genera of lice, one that is shared with chimpanzees and another that is shared with gorillas. In this study, we reconstruct the evolutionary history of primate lice and infer the historical events that explain the current distribution of these lice on their primate hosts.

Inconsistency in operationally defining sleep efficiency (SE) creates confusion with regard to the conceptualization and use of the construct by researchers and clinicians. The source of the inconsistency is the denominator of the widely published operational definition of SE: ratio of total sleep time (TST) to time in bed (TIB) (multiplied by 100 to yield a percentage). When taken literally, TIB includes non-sleep-related activity (e.g., reading, texting, conversing with a partner, watching television) both prior to initiating sleep and after the final awakening. However, the construct of SE refers to TST compared to the amount of time spent attempting to initially fall asleep and sleep discontinuity. Non-sleep related activities in bed do not reflect that construct. Also, time out of bed during nighttime awakenings, a manifestation of sleep discontinuity, should be included in the SE denominator. Using TIB as the denominator can also create a methodological problem when SE is an outcome measure in sleep intervention research. It is proposed that research and practice would benefit by clarifying and adopting a consistent operational definition that more accurately captures the construct of SE. An alternate denominator, duration of the sleep episode (DSE), is suggested, where DSE = sleep onset latency (SOL) + TST + time awake after initial sleep onset but before the final awakening (WASO) + time attempting to sleep after final awakening (TASAFA). The proposed formula for SE would be: SE = TST / DSE (× 100). DSE can be easily calculated using standard sleep diary entries along with one item from the Expanded Consensus Sleep Diary. Implications for insomnia research and practice are discussed.

Two studies investigated the domain of attitudes about condom use as an AIDS-relevant behavior and their relation to serf-reported condom use, past and intended. In so doing, the Condom Attitude Scale (CAS) was developed. Subjects for both studies (n = 248, n = 528) were undergraduates, primarily heterosexual. Factor analysis of the initial item pool indicated 8 attitude factors (subscales). The total CAS, its subscales, and measures of condom use had high internal consistency. The total CAS and the majority of subscales explained a substantial amount of variance in condom use and in carrying and keeping condoms at home. Gender was unrelated to past and intended condom use. However, despite having generally more positive attitudes about condoms, women were more inhibited about buying and keeping condoms and were less likely to do so. Test-retest and cross-validation analyses revealed, for the most part, consistent findings.

Extensive portions of the southern Everglades are characterized by series of elongated, raised peat ridges and tree islands oriented parallel to the predominant flow direction, separated by intervening sloughs. Tall herbs or woody species are associated with higher elevations and shorter emergent or floating species are associated with lower elevations. The organic soils in this ''Ridge-and-Slough'' landscape have been stable over millennia in many locations, but degrade over decades under altered hydrologic conditions. We examined soil, pore water, and leaf phosphorus (P) and nitrogen (N) distributions in six Ridge and Slough communities in Shark Slough, Everglades National Park. We found P enrichment to increase and N to decrease monotonically along a gradient from the most persistently flooded sloughs to rarely flooded ridge environments, with the most dramatic change associated with the transition from marsh to forest. Leaf N:P ratios indicated that the marsh communities were strongly P-limited, while data from several forest types suggested either N-limitation or co-limitation by N and P. Ground water stage in forests exhibited a daytime decrease and partial nighttime recovery during periods of surface exposure. The recovery phase suggested re-supply from adjacent flooded marshes or the underlying aquifer, and a strong hydrologic connection between ridge and slough. We therefore developed a simple steady-state model to explore a mechanism by which a phosphorus conveyor belt driven by both evapotranspiration and the regional flow gradient can contribute to the characteristic Ridge and Slough pattern. The model demonstrated that evapotranspiration sinks at higher elevations can draw in low concentration marsh waters, raising local soil and water P concentrations. Focusing of flow and nutrients at the evapotranspiration zone is not strong enough to overcome the regional gradient entirely, allowing the nutrient to spread downstream and creating an elongated concentration plume in the direction of flow. Our analyses suggest that autogenic processes involving the effects of initially small differences in topography, via their interactions with hydrology and nutrient availability, can produce persistent physiographic patterns in the organic sediments of the Everglades.