Vehicle routing and staffing for sedan service

We present the optimization component of a decision support system developed for a sedan service provider. The system assists supervisors and dispatchers in scheduling driver shifts and routing the fleet throughout the day to satisfy customer demands within tight time windows. We periodically take a snapshot of the dynamic data and formulate an integer program, which we solve to near optimality using column generation. Although the data snapshot is stale by the time a solution is computed, we are able to solve the integer program quickly enough that the solution can be adopted after minor modifications are made by a fast local-search heuristic. The system described in this paper is currently in use and has improved the provider’s productivity significantly

[Re(CO)₃]⁺ Complexes of <i>exo</i>-Functionalized Tridentate “Click” Macrocycles: Synthesis, Stability, Photophysical Properties, Bioconjugation, and Antibacterial Activity

There is considerable interest in the development of bifunctional ligand scaffolds for the group 7 metals due to potential biological applications. Building on our recent work in the development of “click” ligands and macrocycles, we show that a CuAAC “click” approach can be exploited for the synthesis of a small family of bioconjugated tridentate pyridyl-1,2,3-triazole macrocycles. These bioconjugated tridentate macrocycles form stable [Re­(CO)₃]⁺ complexes, and this could facilitate the development of [M­(CO)₃]⁺ (M = Mn, Tc, Re) targeted agents. The parent macrocycle, bioconjugates, and [Re­(CO)₃]⁺ complexes were characterized by elemental analysis and HR-ESI-MS, ¹H and ¹³C NMR, and IR spectroscopy, and the molecular structures of the alcohol-functionalized macrocycle and two of the Re­(I) complexes were confirmed by X-ray crystallography. The electronic structure of the parent [Re­(CO)₃]⁺ macrocycle complex was examined using UV–vis, Raman, and emission spectroscopy and density functional theory calculations. The complex exhibited intense absorptions in the UV region which were modeled using time-dependent density functional theory (TD-DFT). The calculations suggest that the lower energy part of the absorption band is MLCT in nature and additional higher energy π–π* transitions are present. The complex was weakly emissive at room temperature in methanol with a quantum yield of 5.1 × 10^–3 and correspondingly short excited state lifetime (τ ≈ 20 ns). The family of macrocycles and the corresponding Re­(I) complexes were tested for antimicrobial activity <i>in vitro</i> against both Gram positive (Staphylococcus aureus) and Gram negative (Escherichia coli) microorganisms. Agar-based disk diffusion assays indicated that two of the Re­(I) complexes displayed antimicrobial activity but the minimum inhibitory concentrations (MIC) for these compounds proved to be extremely modest (MIC > 256 μg/mL)

Crônica de uma praga anunciada epidemias agrícolas e história ambiental do café nas Américas Chronicle of a plague foretold crop epidemics and the environmental history of coffee in the Americas

As epidemias agrícolas fornecem um ponto de vista privilegiado para a história ambiental global e transnacional de commodities. A epidemia da ferrugem, causada pelo fungo Hemileia nastatrix, é uma das mais sérias doenças que têm atingido a indústria global de café. No século XIX, ela devastou as plantações de café no Velho Mundo. Também reduziu agudamente a produção de café do tipo arábica na África, Ásia e no Pacífico. Esse foi um dos fatores que permitiu aos países da Américas dominarem a produção global no século XX. Essa epidemia foi detectada nas Américas pela primeira vez na década de 1970. A sua história nas Américas, e as tentativas de seu controle lançam luzes sobre dois paradigmas maiores que moldaram a história ambiental do café no final do século XX. São eles: o paradigma tecnicista, dominante entre meados do século XX até o início dos anos 1990; e o paradigma da sustentabilidade, cujo domínio emergiu em meados dos anos 1980 e se mantém até o presente.<br>Crop epidemics provide a portal into the global and transnational environmental history of commodities. The coffee rust epidemic, caused by the fungus Hemileia vastatrix, is one of the most serious diseases to have afflicted the global coffee industry. In the nineteenth century, it devastated the coffee plantations in the Old World. It sharply curtailed arabica coffee production in Africa, Asia, and the Pacific. This was one of the factors that allowed the Americas do dominate global coffee production in the twentieth century. The coffee rust epidemic was first detected in the Americas in the 1970s. The history of the rust epidemic in the Americas, and attempts to control it, shed light on two major paradigms that shaped the environmental history of coffee in the late twentieth century. The paradigm of technification, which dominated from the mid-20th century to the early 1990s; and the paradigm of sustainability, which dominated emerged in the mid-1980s and continues to the present