Beetle 'horns' are rigid outgrowths of the insect cuticle used as weapons in contests for access to mates. Relative to their body size, beetle horns can be enormous. They protrude from any of five different regions of the head or thorax; they are curved, straight, branched or bladed; and their development is often coupled with the nutrient environment (male dimorphism) or with sex (sexual dimorphism). Here, we show that this extraordinary diversity of horns can be distilled down to four trajectories of morphological change -horn location, shape, allometry and dimorphism -and we illustrate how the developmental mechanisms regulating horn growth could generate each of these types of horn evolution. Specifically, we review two developmental pathways known to regulate growth of morphological structures in Drosophila and other insects: a limb-patterning pathway that specifies the location and shape of a structure, and the insulin pathway, which modulates trait growth in response to larval nutrition. We summarize preliminary evidence indicating that these pathways are associated with the development of beetle horns, and we show how subtle changes in the relative activities of these two pathways would be sufficient to generate most of the extant diversity of horn forms. Our objective is to intuitively connect genotype with phenotype, and to advocate an informed 'candidate gene' approach to studies of the developmental basis of evolution. We end by using this insight from development to offer a solution to the longstanding mystery of the scarabs: the observation by Darwin, Lameere, Arrow and others that this one family of beetles appeared to have a 'special tendency' towards the evolution of horns.

PURPOSE This study describes key elements of the transition to a patient-centered medical home (PCMH) model at Southcentral Foundation (SCF), a tribally owned and managed primary care system, and evaluates changes in emergency care use for any reason, for asthma, and for unintentional injuries, during and after the transition. METHODSWe conducted a time series analyses of emergency care use from medical record data. We also conducted 45 individual, in-depth interviews with PCMH patients (customer-owners), primary care clinicians, health system employees, and tribal leaders. RESULTSEmergency care use for all causes was increasing before the PCMH implementation, dropped during and immediately after the implementation, and subsequently leveled off. Emergency care use for adult asthma dropped before, during, and immediately after implementation, subsequently leveling off approximately 5 years after implementation. Emergency care use for unintentional injuries, a comparison variable, showed an increasing trend before and during implementation and decreasing trends after implementation. Interview participants observed improved access to primary care services after the transition to the PCMH tempered by increased staff fatigue. Additional themes of PCMH transformation included the building of relationships for coordinated, team-based care, and the important role of leadership in PCMH implementation.CONCLUSIONS All reported measures of emergency care use show a decreasing trend after the PCMH implementation. Before the implementation, overall use and use for unintentional injuries had been increasing. The combined quantitative and qualitative results are consistent with decreased emergency care use resulting from a decreased need for emergency care services due to increased availability of primary care services and same-day appointments.

BackgroundBetween 1995 and 1998, tribally owned Southcentral Foundation (SCF) incrementally assumed responsibility from the Indian Health Service (IHS) for primary care services on the Alaska Native Medical Center (ANMC) campus in Anchorage, Alaska. In 1999, SCF began implementing components of a Patient-Centered Medical Home (PCMH) model to improve access and continuity of care.ObjectiveTo evaluate hospitalisation trends before, during and after PCMH implementation.DesignTime series analysis of aggregated medical record data.MethodsRegression analysis with correlated errors was used to estimate trends over time for the percent of customer-owners hospitalised overall and for specific conditions during 4 time periods (March 1996–July 1999: SCF assumes responsibility for primary care; August 1999–July 2000: PCMH implementation starts; August 2000–April 2005: early post-PCMH implementation; May 2005–December 2009: later post-PCMH implementation). Analysis was restricted to individuals residing in Southcentral Alaska and receiving health care at ANMC.ResultsThe percent of SCF customer-owners hospitalised per month for any reason was steady before and during PCMH implementation, declined steadily immediately following implementation and subsequently stabilised. The percent hospitalised per month for unintentional injury or poisoning also declined during and after the PCMH implementation. Among adult asthma patients, the percent hospitalised annually for asthma declined prior to and during implementation and remained lower thereafter. The percent of heart failure patients hospitalised annually for heart failure remained relatively constant throughout the study period while the percent of hypertension patients hospitalised for hypertension shifted higher between 1999 and 2002 compared to earlier and later years.ConclusionImplementation of PCMH at SCF was accompanied by decreases in the percent of customer-owners hospitalised monthly for any reason and for unintentional injury and in the percent of asthma patients hospitalised annually for asthma. Increased accessibility to empanelled care teams may have contributed to decreased need for hospitalisation.

During retroviral replication, full-length viral RNAs are encapsidated into new virus particles, while spliced RNAs are excluded. The Retroviridae are unique among viruses in that infectious viral particles contain a dimer of two identical genomic RNA strands. A variety of experimental data has suggested that dimerization and encapsidation of full-length viral RNAs are linked processes, although whether dimerization is a prerequisite for encapsidation, or conversely, dimerization follows encapsidation, has not been firmly established. If dimerization was the sole determinant for encapsidation, then spliced viral RNAs might be expected to display a reduced capacity for dimerization, resulting in their exclusion from the dimerization pool. Here, we studied the in vitro dimerization properties of unspliced and spliced HIV-2 RNA. We find that the rate and yield of dimerization of Nef, Rev and Tat spliced RNAs exceeded those of unspliced RNA. Although these data do not support a simple correlation between dimerization efficiency and the presence of introns, they establish that splicing affects the presentation of dimerization signal(s), which we corroborate with structure probing. This change in RNA conformation likely affects the RNA's suitability for packaging. Furthermore, the presence of upstream and downstream elements that affect the conformation of the packaging signal represents a potentially efficient viral strategy for correctly sorting spliced versus unspliced RNAs.