Farthest-Polygon Voronoi Diagrams

Given a family of k disjoint connected polygonal sites in general position and of total complexity n, we consider the farthest-site Voronoi diagram of these sites, where the distance to a site is the distance to a closest point on it. We show that the complexity of this diagram is O(n), and give an O(n log^3 n) time algorithm to compute it. We also prove a number of structural properties of this diagram. In particular, a Voronoi region may consist of k-1 connected components, but if one component is bounded, then it is equal to the entire region

A historical overview of Western medicine and health in Ghana in the twentieth century

Traditional therapy was dominant in Ghana. However, by the 19th to 20th centuries, scientific medicine had been fully introduced to the people of Ghana. There is a growing tendency in the research of medicine in Ghana. Some scholarly works had been published on Western medicine; however, all these works had not been brought together in analyzing the history of scientific medicine in Ghana. This work conducts an opportunistic historical overview of Western medicine and health in Ghana through the twentieth century. This is to bring to light some scholarly literature on Western medicine in Ghana, of which further research could be conducted. Some selected works that were relevant in the study of the history of western medical practices and health issues in Ghana were looked at

Over 10% efficient wide bandgap CIGSe solar cells on transparent substrate with Na predeposition treatment

With the recent rise of new photovoltaic applications, it has become necessary to develop specific optoelectronic properties for thin-film technologies such as Cu(In,Ga)Se2 and to take advantage of their high degree of tunability. The feasibility of efficient wide bandgap absorbers on transparent conductive oxide substrates is, in that context, of critical importance. Using an original approach based on a predeposition sodium treatment, Cu(In,Ga)Se2 absorbers fabricated by sputtering and reactive annealing with a Ga to (Ga + In) content over 0.7 and an optical bandgap above 1.4 eV are deposited on transparent fluorine-doped tin oxide films, with the insertion of an ultrathin MoSe2 layer preserving the contact's ohmicity. Different material characterizations are carried out, and a thorough Raman analysis of the absorber reveals that the sodium pretreatment significantly enhances the Ga incorporation into the chalcopyrite matrix, along with markedly improving the film's morphology and crystalline quality. This translates to a spectacular boost of the photovoltaic performance for the resulting solar cell as compared with a reference device without Na, specifically in the voltage and fill factor. Eventually, an efficiency exceeding 10% is obtained without antireflection coating, a record value bridging the gap with the state of the art on nontransparent substrates.Peer ReviewedPostprint (author's final draft

Multifluorescence High‐Resolution Episcopic Microscopy for 3D Imaging of Adult Murine Organs

3D microscopy of large biological samples (>0.5 cm^{3})is transforming biological research. Many existing techniques require trade-offs between image resolution, sample size, and method complexity. A simple robust instrument with the potential to conduct large-volume 3D imaging currently exists in the form of the optical high-resolution episcopic microscopy (HREM). However, the development of the instrument to date is limited to single-fluorescent wavelength imaging with nonspecific eosin staining. Herein, developments to realize the potential of the HREM to become multifluorescent high-resolution episcopic microscopy (MF-HREM) are presented. MF-HREM is a serial-sectioning and block-facing wide-field fluorescence imaging technique, which does not require tissue clearing or optical sectioning. Multiple developments are detailed in sample preparation and image postprocessing to enable multiple specific stains in large samples and show how these enable segmentation and quantification of the data. The application of MF-HREM is demonstrated in a variety of biological contexts: 3D imaging of whole tumor vascular networks and tumor cell invasion in xenograft tumors up to 7.5 mm^{3} at resolutions of 2.75 μm, quantification of glomeruli volume in the adult mouse kidney, and quantification of vascular networks and white-matter track orientation in adult mouse brain

Modeling a Hybrid Reformed Methanol Fuel Cell–Battery System for Telecom Backup Applications

In this paper, a hybrid reformed methanol fuel cell–battery system for telecom backup applications was modeled in MATLAB Simulink. The modeling was performed to optimize the operating strategy of the hybrid system using an energy management system with a focus on a longer lifetime and higher fuel efficiency for the fuel cell, while also keeping the state-of-charge (SOC) of the battery within a reasonable range. A 5 kW reformed methanol fuel cell stack and a 6.5 kWh Li-ion battery were considered for the hybrid model. Moreover, to account for the effects of degradation, the model evaluated the performance of the fuel cell both in the beginning of life (BOL) and after 1000 h and 250 start–stop cycling tests (EOT). The energy management system (EMS) was characterized by 12 operating conditions that used the battery SOC, load requirements and the presence or absence of grid power as the inputs to optimize the operating strategy for the system. Additionally, the integration of a 400 W photovoltaic (PV) system was investigated and was able to supplement the battery SOC, thereby increasing the stability and reliability of the system. However, extensive power outages during the night could lead to low battery SOC and, therefore, critical operating conditions and the extended use of the fuel cell. The model also predicted the methanol consumption for different scenarios

Platelet-Induced Clumping of Plasmodium falciparum–Infected Erythrocytes from Malawian Patients with Cerebral Malaria—Possible Modulation In Vivo by Thrombocytopenia

Platelets may play a role in the pathogenesis of human cerebral malaria (CM), and they have been shown to induce clumping of Plasmodium falciparum–parasitized red blood cells (PRBCs) in vitro. Both thrombocytopenia and platelet-inducedPRBCclumping are associated with severe malaria and, especially, withCM.In the present study, we investigated the occurrence of the clumping phenomenon in patients with CM by isolating and coincubating their plasma and PRBCs ex vivo. Malawian children with CM all had low platelet counts, with the degree of thrombocytopenia directly proportional to the density of parasitemia. Plasma samples obtained from these patients subsequently induced weak PRBC clumping. When the assays were repeated, with the plasma platelet concentrations adjusted to within the physiological range considered to be normal, massive clumping occurred. The results of this study suggest that thrombocytopenia may, through reduction of platelet-mediated clumping of PRBCs, provide a protective mechanism for the host during CM