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The nonlinear development of a low frequency beam-cyclotron instability in a collisional plasma composed of magnetized ions and electrons and unmagnetized, negatively charged dust is investigated using one-dimensional particle-in-cell simulations. Collisions of charged particles with neutrals are taken into account via a Langevin operator. The instability, which is driven by an ion
drift, excites a quasi-discrete wavenumber spectrum of waves that propagate perpendicular to the magnetic field with frequency of the order of the dust plasma frequency. In the linear regime, the unstable wavelengths are of the order of the ion gyroradius. As the wave energy density increases, the dominant modes shift to longer wavelengths, suggesting a transition to a Hall-current-type instability. Parameters are considered that reflect the ordering of plasma and dust quantities in laboratory dusty plasmas with high magnetic field. Comparison with the nonlinear development of this beam cyclotron instability in a collisionless dusty plasma is also briefly discussed.
Although the Este family had traditionally supported numerous monastic foundations, Borso d'Este's patronage of the Carthusian order is notable in that it introduced a new religious community into Ferrara. The history of the establishment, development, and decoration of the Charterhouse of Ferrara is indicative of the taste, artistic and religious views, and political exigencies which shaped the religious patronage of Borso d'Este, Duke of Ferrara, Modena, and Reggio. At the same time, the specific examples of Borso's monastic patronage are illustrative of the fundamental assumptions underlying fifteenth-century aristocratic support of religious foundations.
On April 23,1452, Borso d'Este laid the cornerstone for the Certosa on a site not far from the Este villa of Belfiore and the Dominican Monastery of Santa Maria degli Angeli. By spring 1461, the Monastery was habitable, though not yet complete.
Giardia duodenalis is the most common intestinal parasite of humans in the USA, but the risk factors for sporadic (non-outbreak) giardiasis are not well described. The Centers for Disease Control and Prevention and the Colorado and Minnesota public health departments conducted a case-control study to assess risk factors for sporadic giardiasis in the USA. Cases (N = 199) were patients with non-outbreak-associated laboratory-confirmed Giardia infection in Colorado and Minnesota, and controls (N = 381) were matched by age and site. Identified risk factors included international travel (aOR = 13.9; 95% CI 4.9–39.8), drinking water from a river, lake, stream, or spring (aOR = 6.5; 95% CI 2.0–20.6), swimming in a natural body of water (aOR = 3.3; 95% CI 1.5–7.0), male–male sexual behaviour (aOR = 45.7; 95% CI 5.8–362.0), having contact with children in diapers (aOR = 1.6; 95% CI 1.01–2.6), taking antibiotics (aOR = 2.5; 95% CI 1.2–5.0) and having a chronic gastrointestinal condition (aOR = 1.8; 95% CI 1.1–3.0). Eating raw produce was inversely associated with infection (aOR = 0.2; 95% CI 0.1–0.7). Our results highlight the diversity of risk factors for sporadic giardiasis and the importance of non-international-travel-associated risk factors, particularly those involving person-to-person transmission. Prevention measures should focus on reducing risks associated with diaper handling, sexual contact, swimming in untreated water, and drinking untreated water.
Factors associated with relapse among children who are discharged after reaching a threshold denoted ‘recovered’ from moderate acute malnutrition (MAM) are not well understood. The aim of this study was to identify factors associated with sustained recovery, defined as maintaining a mid-upper-arm circumference≥12·5 cm for 1 year after release from treatment. On the basis of an observational study design, we analysed data from an in-depth household (HH) survey on a sub-sample of participants within a larger cluster randomised controlled trial (cRCT) that followed up children for 1 year after recovery from MAM. Out of 1497 children participating in the cRCT, a subset of 315 children participated in this sub-study. Accounting for other factors, HH with fitted lids on water storage containers (P=0·004) was a significant predictor of sustained recovery. In addition, sustained recovery was better among children whose caregivers were observed to have clean hands (P=0·053) and in HH using an improved sanitation facility (P=0·083). By contrast, socio-economic status and infant and young child feeding practices at the time of discharge and HH food security throughout the follow-up period were not significant. Given these results, we hypothesise that improved water, sanitation and hygiene conditions in tandem with management of MAM through supplemental feeding programmes have the possibility to decrease relapse following recovery from MAM. Furthermore, the absence of associations between relapse and nearly all HH-level factors indicates that the causal factors of relapse may be related mostly to the child’s individual, underlying health and nutrition status.
The dust acoustic, or dust density, wave is a very low frequency collective mode in a dusty plasma that is associated with the motion of the charged and massive dust grains. An ion flow due to an electric field can excite these waves via an ion–dust streaming instability. Theories of this instability have often assumed a shifted-Maxwellian ion velocity distribution. Recently, the linear kinetic theory of this instability was considered using a non-Maxwellian ion velocity distribution (Kählert, Phys. Plasmas, vol. 22, 2015, 073703). In this paper, we present one-dimensional PIC simulations of the nonlinear development of the ion–dust streaming instability, comparing the results for these two types of ion velocity distributions, for several values of the ion drift speed and collision rate. Parameters are considered that reflect the ordering of plasma and dust quantities in laboratory dusty plasma experiments. It is found that, in general, the wave energy density is smaller in the simulations with a non-Maxwellian ion distribution.