Light curves and colours of the ejecta from Dimorphos after the DART impact.

On 26 September 2022, the Double Asteroid Redirection Test (DART) spacecraft struck Dimorphos, a satellite of the asteroid 65803 Didymos1. Because it is a binary system, it is possible to determine how much the orbit of the satellite changed, as part of a test of what is necessary to deflect an asteroid that might threaten Earth with an impact. In nominal cases, pre-impact predictions of the orbital period reduction ranged from roughly 8.8 to 17 min (refs. 2,3). Here we report optical observations of Dimorphos before, during and after the impact, from a network of citizen scientists' telescopes across the world. We find a maximum brightening of 2.29 ± 0.14 mag on impact. Didymos fades back to its pre-impact brightness over the course of 23.7 ± 0.7 days. We estimate lower limits on the mass contained in the ejecta, which was 0.3-0.5% Dimorphos's mass depending on the dust size. We also observe a reddening of the ejecta on impact.

Israeli acute paralysis virus: epidemiology, pathogenesis and implications for honey bee health.

Israeli acute paralysis virus (IAPV) is a widespread RNA virus of honey bees that has been linked with colony losses. Here we describe the transmission, prevalence, and genetic traits of this virus, along with host transcriptional responses to infections. Further, we present RNAi-based strategies for limiting an important mechanism used by IAPV to subvert host defenses. Our study shows that IAPV is established as a persistent infection in honey bee populations, likely enabled by both horizontal and vertical transmission pathways. The phenotypic differences in pathology among different strains of IAPV found globally may be due to high levels of standing genetic variation. Microarray profiles of host responses to IAPV infection revealed that mitochondrial function is the most significantly affected biological process, suggesting that viral infection causes significant disturbance in energy-related host processes. The expression of genes involved in immune pathways in adult bees indicates that IAPV infection triggers active immune responses. The evidence that silencing an IAPV-encoded putative suppressor of RNAi reduces IAPV replication suggests a functional assignment for a particular genomic region of IAPV and closely related viruses from the Family Dicistroviridae, and indicates a novel therapeutic strategy for limiting multiple honey bee viruses simultaneously and reducing colony losses due to viral diseases. We believe that the knowledge and insights gained from this study will provide a new platform for continuing studies of the IAPV-host interactions and have positive implications for disease management that will lead to mitigation of escalating honey bee colony losses worldwide.

The emergence of family medicine in Kyrgyzstan.

BACKGROUND AND OBJECTIVES: In post-Soviet Central Asia, Kyrgyzstan has emerged as the leader in family medicine reform. This paper examines the factors that have allowed family medicine to become the foundation of primary care and the rationale for retraining specialists in primary care. METHODS: Critical elements of successful family medicine reform have included national policy, international cooperation, training programs, support structures, and quality measures. The national policy has contributed to an environment that has allowed many international organizations to participate in the process of reforming the health care system. The 9-year training process was a momentous nationwide development task that was supported by various structures, organizations, and events and included the implementation of quality measures. ANALYSIS: Various reports, studies, and evaluations support the positive impact family medicine has had on patient satisfaction, physician attitude, and scope of practice. Further, one study indicates improved health outcomes in terms of decreased years of potential life lost. RESULTS: The national policy of reform that is in favor of family medicine, and international donor agencies-supported training, produced the following results: a group of family medicine teachers, 98% (2,691) of the country's primary care doctors retrained in family medicine, and there were 372 family medicine resident graduates. To ensure quality, objective structured clinical exams were implemented in all levels of training. CONCLUSIONS: It will take many more years to fully establish family medicine in the medical culture of Kyrgyzstan and reap its full benefits, but already it is contributing toward improvements in the quality of patient care.

Power dissipation and time-averaged pressure in oscillating flow through a sudden area change.

Experiments on oscillating flow at the abrupt transition between a two-dimensional channel and essentially infinite space are presented. It is shown that phenomena associated with the transition are functions of three independent dimensionless parameters including the dimensionless radius rounding the edge of the end of the channel. The effect of each of these three parameters on the time-averaged pressure difference across the transition and the acoustic power dissipation is explored by holding two parameters fixed while varying the third. Evidence is presented that the losses due to oscillatory flow in this geometry are smaller than would be expected from commonly accepted values for steady flow in similar geometry.