Modeling Urban Freight Generation: A Study of Commercial Establishments’ Freight Needs

Increasing urbanization, and the environmental and liveability impacts associated with urban activity, have directed attention to the need for sustainable cities. Achieving sustainable urban development requires including freight systems in strategic urban development plans. In this context, joint efforts involving academia and public- and private sector to collect the right data and develop suitable models, can contribute toward a better understanding of establishments’ freight needs, the quantification of freight’s traffic impacts and the development of appropriate methods to support decision making and strategic plans. This paper studies urban commercial establishments’ freight needs and impacts on traffic using data collected from establishments in the City of Gothenburg (Sweden). The data cover different zones of the city and include commercial sectors found typically in urban cores (e.g., retailers, food services, health care, public sector offices and education). The paper introduces a set of statistical models—developed based on regression analyses and discrete choice models—to estimate the number of freight trips produced and attracted per week, and the attraction of weight and volumes of freight. In addition to shed light on the factors determining establishments’ freight- and freight trips generation, the models are designed with the purpose of assisting planning and policy design efforts, thus the explanatory variables are selected based on suitability and availability. The results show that retailers of perishable goods have the highest freight trip generation per establishment, followed by public sector offices and education establishments, retailers of non-perishable goods and restaurants. The results also reveal a heterogeneity between sectors, and a differential business size effect across commercial sectors

Assessing the magnitude of freight traffic generated by office deliveries

This paper studies the impact of offices on urban freight traffic. Research on freight activity generated by offices is very limited because they are not seen as important contributors to urban freight traffic, and because the amount of deliveries per office is very small compared to the number of deliveries per establishment in freight-intensive sectors (e.g., retail, wholesale, manufacturing). However, the number of offices in cities is so large that altogether they represent a significant share of urban deliveries and generate a nonnegligible share of urban freight traffic. Hence, the relevance of quantifying their freight trip generation. This paper uses the City of Stockholm as a case study. The author collected data from offices and other establishments, estimated regression models and applied them to the city. The results show that offices represent 36% of establishments in Stockholm, 62% of employees and are responsible for 15% of freight trips generated in the city

An Olefin Metathesis-Based Strategy for the Synthesis of New Antitumoral Compounds Inspired by Natural Products

In particular, one precursor showed potent antiangiogenic effect in vitro and in vivo, suggesting the potential therapeutic application of solomonamide derivatives as inhibitors of the persistent and deregulated angiogenesis that characterizes cancer. For the last target, the celebesides, [26]-membered cyclodepsipeptides with anti-HIV activity, we envisioned a RCM reaction to access their macrocyclic core. We established a solid-phase synthesis strategy for the preparation of the peptidic chain, while the synthesis of the polyketide fragment was achieved in a stereoselective manner. Fecha de lectura de Tesis Doctoral: 13 de diciembre 2019.his PhD Thesis proposes the discovery and development of new drugs inspired by bioactive natural products, which represent valid platforms for the generation of new chemical entities of pharmaceutical interest. In particular, the selected natural products are (-)-depudecin, solomonamides and celebesides. We have established synthetic strategies oriented to the target, but with the possibility of the extension of such strategies to the construction of a molecular diversity through the generation of analogues. For the synthesis of (-)-depudecin, a unique antitumoral detransforming agent, we have established a new convergent total synthesis utilizing an olefin cross-metathesis (CM) reaction as the key step. In addition, the synthetic route was amenable to stereochemical and functional modifications, allowing the preparation of several analogues, which were used for a structure-activity relationship (SAR) study in order to identify new leads based on depudecin. In the case of the solomonamides, we have developed a synthetic strategy that comprises two phases: a) a cyclisation phase for the construction of the [15]-membered ring contained in these cyclopeptides utilizing an olefin ring-closing metathesis (RCM) as the key reaction; and b) an oxidation phase to give access to the natural products that would allow for the generation of a variety of analogues via oxidative transformations. In addition, we identified several structurally related solomonamide precursors possessing significant cytotoxicities against various tumor cell lines

Managing household freight: The impact of online shopping on residential freight trips

Freight transport management and planning traditionally relies on freight transport models. However, e -commerce has changed the way freight is transported and requires a paradigm shift in such models. In contrast to conventional purchases in physical outlets, there is a spatial and temporal disconnection between the purchase and the reception of goods bought online. While traditionally the shopper brings home the purchases, the courier, express and parcel (CEP) sector must bridge this leg for the online retail channel by delivering the parcel to the household. These new type of freight trips have been ignored in the literature on freight modeling. Given the increasing number of urban freight trips destined for households, this omission implies significant errors when demonstrating transport impacts, identifying potential innovations, or assessing policy initiatives with these models. Therefore, we develop a framework that demonstrates how households\u27 online consumption translates into freight trips. Three key factors in this framework seem to determine the magnitude of freight traffic originated by household\u27s online shopping: (i) consumer shopping behavior, (ii) the supplier network and distribution system designed by the online store, and (iii) the fragmentation of the CEP market and the density of the delivery network. The identification of these three key factors provides a framework for policy action to mitigate the impact of household freight

Simultaneous Bifurcation of Limit Cycles and Critical Periods

Altres ajuts: Acord transformatiu CRUE-CSICThe present work introduces the problem of simultaneous bifurcation of limit cycles and critical periods for a system of polynomial differential equations in the plane. The simultaneity concept is defined, as well as the idea of bi-weakness in the return map and the period function. Together with the classical methods, we present an approach which uses the Lie bracket to address the simultaneity in some cases. This approach is used to find the bi-weakness of cubic and quartic Liénard systems, the general quadratic family, and the linear plus cubic homogeneous family. We finish with an illustrative example by solving the problem of simultaneous bifurcation of limit cycles and critical periods for the cubic Liénard family

Development and Initial Validation of a Surgical Instrument for In Situ Mechanical Characterization of Surgical Mesh-tissue Composites

Approximately 5 million Americans have an abdominal wall hernia, and over 700,000 undergo surgical procedures every year to treat them. Surgical procedures have evolved with the goal of preventing recurrences, leading to the current gold standard of treatment: hernia repair with mesh. Hernia repair with mesh consists on augmenting the weakened abdominal wall by implanting a synthetic or biological mesh. Although the adoption of hernia repair with mesh has improved outcomes, recurrence from primary repair procedures with large incisions (\u3e10 cm) remains an alarming 32%. The wide variety of implanted surgical mesh (materials, structure) and surgical variability (attachment method, laparoscopic versus open surgery) have been voiced as concerns by national and international agencies, which have called for reporting of these variables to relate them to patient outcomes. Variables related to the mechanical aspect of the mesh in situ have yet to receive attention, mainly due to the lack of instrumentation practical for adoption in the surgical setting. A variable currently assessed subjectively by surgeons during implantation is the stiffness of the abdominal wall and mesh, sampled by applying a distension load to mesh in situ using a blunt probe or by hand. Through the work in this thesis, the development of a handheld instrument to measure the stiffness of the abdominal wall and mesh under a distentional load was accomplished. An iterative design process was followed to meet design requirements established by mechanical tissue models and voice of the customer input. The instrument’s sensing accuracy and precision were confirmed by comparison with standardized bench top equipment. Verification was achieved through in vitro testing of composites simulating iii the abdominal wall and mesh. The instrument consistently measured different stiffness values (p\u3c0.04) on samples overlaid with polyethylene sheets or a commercially available surgical mesh under varying tension. In vivo testing on swine specimens provided preliminary validation of the instrument’s ability to discern distentional stiffness changes of the abdominal wall composite due to mesh implantation (p\u3c0.04). Adoption of the instrument presented here will allow for the study of a mechanical variable considered relevant by surgeons, and may expose a link between mechanical implantation variables and patient outcomes through long term clinical studies

Property owners as possible game changers for sustainable urban freight

Commercial activity and the underlying freight movements supporting them are essential to urban life. Unfortunately, urban freight has negative effects on sustainability and requires innovative approaches to enhance the positive aspects and minimize the negative ones. There is a common understanding among practitioners, with support from the literature, that the negative impacts of urban freight can be alleviated with better knowledge about the system and by identifying and engaging influential stakeholders. This paper focuses on property owners and their role in encouraging initiatives that lead to more sustainable urban freight delivery practices. Property owners engage in sustainability issues in real estate because they are interested in developing their properties to increase their attractiveness, competitiveness, and future market value. A shopping mall is an example of a property that generates a lot of freight traffic due to intense commercial activity. This paper studies the delivery patterns to a centrally located shopping mall in the city of Gothenburg and identifies how property owners could influence the delivery patterns of their tenants. A range of initiatives is proposed based on the literature and considering the delivery patterns observed. The results show that property owners can include freight deliveries in their sustainability strategy, focusing on fostering collaboration and communication between the tenants and promoting supply chain strategies that consider the type of activities that take place and the scope to reduce the number of truck movements and increase the efficient and sustainable goods deliveries

El Devenir Inmediato de la Reforma y Gestión Universitaria en México y sus Tareas en el Marco de la Agenda Mundial

En su devenir inmediato, la universidad como parte integrante del sistema de educación superior, ha venido presentando un conjunto de transformaciones caracterizadas por hechos que han respondido en su momento a dinámicas propias del sistema educativo como también a las de su contexto y sectores con los cuales se vincula. En tales situaciones, las universidades han transitado por un conjunto de reformas y procesos de gestión que han tendido tanto a su adecuación a las necesidades presentes como a su transformación para atender las necesidades emergentes en relación a su objeto de ser. En tales contextos, el presente documento de trabajo hace un recorrido temporal sobre aquellos hechos inmediatos que han sido significativos en las reformas y procesos de gestión académica de las universidades, para luego identificar algunas de las principales tendencias de la educación superior que se presentan en el plano internacional y a partir de ello derivar un conjunto de factores y retos que permiten plantear algunas tareas que se consideran pendientes y necesarias en el marco de las reformas universitarias y sus respectivos procesos de gestión susceptibles de llevar a cabo en los próximos años

Hybrid Nanocomposites with Tunable Alignment of the Magnetic Nanorod Filler

For many important applications, the performance of polymer-anisotropic particle nanocomposite materials strongly depends on the orientation of the nanoparticles. Using the very peculiar magnetic properties of goethite ({\alpha}-FeOOH) nanorods, we produced goethite-poly(hydroxyethyl methacrylate) nanocomposites in which the alignment direction and the level of orientation of the nanorods could easily be tuned by simply adjusting the intensity of a magnetic field applied during polymerization. Because the particle volume fraction was kept low (1-5.5 vol \%), we used the orientational order induced by the field in the isotropic phase rather than the spontaneous orientational order of the nematic phase. At the strongest field values (up to 1.5 T), the particles exhibit almost perfect antinematic alignment, as measured by optical birefringence and small-angle X-ray scattering. The results of these two techniques are in remarkably good agreement, validating the use of birefringence measurements for quantifying the degree of orientational order. We also demonstrate that the ordering induced by the field in the isotropic suspension is preserved in the final material after field removal. This work illustrates the interest, for such problems, of considering the field-induced alignment of anisotropic nanoparticles in the isotropic phase, an approach that is effective at low filler content, that avoids the need of controlling the nematic texture, and that allows tuning of the orientation level of the particles at will simply by adjusting the field intensity