151 research outputs found
The relationship between port choice and terminal involvement of alliance members in container shipping
No full textAbstract: This paper examines in which ways the changing organizational routines of shipping (i.e., alliance formation and vertical integration in container terminal operations) are affecting the selection of ports of call in intercontinental liner service networks. It first provides a conceptual analysis of the interplay between changes (a) in the organizational routines of shipping lines as part of alliances, (b) the organizational routines at the level of terminal operations (i.e. direct carrier equity involvement in terminal operations) and (c) in port calling patterns. The empirical part examines the relationship between port choice of alliance members and the direct involvement of shipping lines in container terminals in North-West European ports. It does so using binary and non-binary data on the evolution of calling patterns on the North Europe-Far East trade from 2006 to 2017. In addition, the changes in both alliance formation during that period and in the container terminal involvement of carriers in North West European ports are addressed. By examining the relationship between port calling patterns of alliances and the terminal interests of alliance members, the paper addresses an under-researched theme in the extant literature on port choice/selection by carriers. The paper is also of value to port managers and shipping professionals in view of port strategy and planning decisions, as well as shipping strategy formulation
Maritime interest representation in the EU. European Political Economy Review Vol. 3, No. 2 (Winter 2005-2006), pp. 6-28
Get PDFThe EU constitutes a supranational policy-making jurisdiction that has moved decisively into the maritime transport policy field. A variety of maritime interests has identified a new level of power with the EU decision-making process and has re-targeted its lobbying strategies in order to influence the Common Maritime Transport Policy (CMTP). This article examines the patterns and the capabilities of this mobilisation. The first part focuses on the structures of these Euro-groups. Then, the analysis turns on the lobbying practices of these interests groups in the context of the EU co-decision process of policy-making. The final part weighs the extent that the ‘EU environment’ and the ‘economic environment’ assist, or undermine, the governability of these lobbying activities and their capacity to be coherent policy actors that serve the interests of their members in the long-term
Peak power reduction algorithms in asymmetric digital subscriber line modems
No full textThesis (M.Eng.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2000.Includes bibliographical references (leaves 94-96).This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.This thesis investigates peak-to-average ratio (PAR) reduction techniques for multicarrier modulation systems, such as discrete multitone (DMT) modems and orthogonal frequency-division multiplexed (OFDM) terrestrial broadcast transmitters. Through simulation and test implementation on a state-of-the-art programmable ADSL development platform, this thesis pursues a suitable solution for minimizing PAR given the resources of a programmable platform. This solution is integrated as a prototype implementation into a fully-functional ADSL modem and optimized for maximum PAR reduction performance within modem complexity constraints.by Athanasios Dimitri Dousis.M.Eng
Is there a standard regimen for first-line treatment of advanced/metastatic Non-Small-Cell Lung Cancer? What has meta-analyses contributed to today's standard of care
No full textTargeted (and chemotherapeutic) agents as maintenance treatment in patients with metastatic non-small-cell lung cancer: Current status and future challenges
No full textMaintenance treatment has been intensively investigated in the field of advanced/metastatic non-small lung cancer in order to improve outcomes in this devastating disease. Two different approaches have been evaluated; the so-called continuation maintenance when the maintenance agent was part of initial therapy and is continued in the absence of disease progression (”maintained”) or switch maintenance when a third agent is initiated after a defined number of cycles chemotherapy in the absence of disease progression. Several phase III trials with both chemotherapeutic and targeted agents have demonstrated either PFS prolongation (continuation maintenance) or both PFS and OS benefit (switch maintenance). Currently, erlotinib and pemetrexed are registered as maintenance treatment in patients with NSCLC not progressing after four cycles of standard platinum-based doublet chemotherapy. However, the development of maintenance treatment has raised a series of questions such as the role of treatment-free intervals, the timing of second-line treatment, selection of patients for maintenance treatment and selection of the most proper agent, and trial design issues such as optimal end-points. The purpose of this paper is to present and discuss the current trials investigating the main treatment paradigms and argue on the above mentioned questions. (C) 2012 Published by Elsevier Ltd
Optical breakdown acoustics : transduction and sensing underwater
No full textThis electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.Thesis: Ph. D., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2019Cataloged from student-submitted PDF version of thesis.Includes bibliographical references (pages 191-199).In the sea, infrastructures such as ships, pipelines, and wind turbines are exposed to harsh conditions that can wear down the structures through wave loading and corrosion. Because of these wear mechanisms, maritime structures require regular inspections to identify early signs of damage or fatigue. Currently, inspections are performed visually or with contact acoustic transducers, often by a human diver. However, these methods are slow and costly, and can be hindered by surface irregularities like biofouling. Therefore, new sensing techniques are needed to meet the rising demand for offshore infrastructure monitoring. In this thesis, I develop optical breakdown as an acoustic source for non-contact measurements of underwater structures. Optical breakdown occurs when a high-power laser is focused to a small spot, causing nonlinear interactions between the light and water. A compact plasma forms at the focus and expands explosively, radiating a loud, broadband pressure wave.Since this source is compact, laser-controlled and broadband, it provides unique sensing capabilities that overcome challenges faced by traditional transducers. First, I demonstrate how the breakdown source can be used to remotely measure the internal properties of submerged plates. The source is used to excite leaky Lamb waves in the plates, and broadband elastic dispersion spectra are measured using hydrophones in the water. The dispersion spectra are used to calculate the thicknesses and sound speeds in aluminum, steel, bronze and glass plates of varying thickness. Second, I characterize how the source can be controlled and scaled up by combining acoustic measurements with high-speed images of the breakdown plasma. In general, breakdown produces a loud (>100kPa at 10cm), ultra-broadband (5kHz-5MHz) source, whose characteristics depend on measurement orientation and laser properties.This transduction behavior is explained by modeling the breakdown plasma as an array of laser-driven explosions. When the laser is tightly focused, the plasma is compact, producing a loud and omnidirectional signal. However, for weak focusing and high energies, the plasma lengthens and becomes erratic, producing a weaker signal with less consistent behavior. These results reveal design challenges, tradeoffs and opportunities when adapting the breakdown source for dierent applications.by Athanasios G. Athanassiadis.Ph. D.Ph.D. Massachusetts Institute of Technology, Department of Mechanical Engineerin
Parallel pulsed jets for precise underwater propulsion
No full textThesis: S.M., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2016.This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.Cataloged from student-submitted PDF version of thesis.Includes bibliographical references (pages 95-98).A significant limitation for underwater robots is their ability to maneuver in tight spaces or for complex tracking tasks. Next generation vehicles require thrusters that can overcome this problem and efficiently provide high maneuverability at low speeds. Recently, thruster design has begun to draw inspiration from nature's swimmers, applying the principles of pulsed jet propulsion to robotic thrusters. Although most developments have focused on single jet actuators, nature provides some indications that multi-jet systems can provide propulsive benefits -- marine invertebrates called sales connect into chains of individual animals that each eject short jets to collaboratively move the entire chain efficiently around the ocean. However, despite the promise of multi-jet propulsion, there are no existing models or empirical data that explain the physics of multi-jet propulsion. As a result, there are no physically motivated rules to guide the design of man-made multi-jet thrusters. In this thesis, I experimentally investigate how interactions between neighboring jets in a multi-jet thruster will affect the system's propulsive performance. I use high-speed fluorescence imaging to investigate the mutual influence of two pulsed jets under conditions relevant to low-speed maneuvering in a vehicle (Re ~ 350). Using a new force estimation technique developed in this thesis, I analyze the video data to evaluate how thrust and efficiency are affected by the jet spacing. This analysis reveals that, compared to non-interacting jets, the efficiency and thrust generated by the pair of interacting jets can fall by nearly 10% as the jets are brought into close proximity. Based on this data, I develop a model of vortex interactions to explain the thrust and efficiency drop. The data and model described in this thesis contribute new insights to understand vortex formation in pulsed jets, and these results can be used to guide the design of multi-jet underwater propulsion systeby Athanasios G. Athanassiadis.S.M
Targeting tumor neovasculature in non-small-cell lung cancer
No full textRecent insight into the molecular biology of cancer and mechanisms of tumorigenesis, has allowed for the identification of several potential molecular targets and the development of novel “targeted therapies”. One of the most active research fields in NSCLC is the discovery of therapies that target angiogenesis. The vascular endothelial growth factor (VEGF) pathway represents a crucial component of the tumor angiogenesis process. Two different strategies have been developed in clinical practice in order to restrict tumor vasculature development; either the use of monoclonal antibodies against VEGF or small molecule tyrosine kinase inhibitors to target the tyrosine kinase domain of VEGF receptor. Among these agents that have been tested bevacizumab, a monoclonal antibody against VEGF, has been approved for the treatment of metastatic NSCLC in combination with chemotherapy, while several other agents are under phase III investigation. Moreover, several issues such as predictive biomarkers of response to antiangiogenic therapy and mechanisms of resistance to these agents remain to be elucidated. The purpose of this paper is to present the current status of antiangiogenic therapies in the treatment of NSCLC and to discuss these issues. (c) 2012 Elsevier Ireland Ltd. All rights reserved
DNA repair pathways and their implication in cancer treatment
No full textMany cytotoxic agents used in cancer treatment exert their effects through their ability to directly or indirectly damage DNA and thus resulting in cell death. Major types of DNA damage induced by anticancer treatment include strand breaks (double or single strand), crosslinks (inter-strand, intra-strand, DNA-protein crosslinks), and interference with nucleotide metabolism and DNA synthesis. On the other hand, cancer cells activate various DNA repair pathways and repair DNA damages induced by cytotoxic drugs. The purpose of the current review is to present the major types of DNA damage induced by cytotoxic agents, DNA repair pathways, and their role as predictive agents, as well as evaluate the future perspectives of the novel DNA repair pathways inhibitors in cancer therapeutics
- …
