Walk or wait?: An empirical analysis of street crossing decisions

We examine the behaviour of pedestrians wishing to cross a stream of trasffic at signalized intersections. We model each padestrian as making a desccrete crossing choice by comparing the gaps between vehicles in traffic to an individual-specific "critical gap" that characterizes the individual's minimal acceptable gap. We propose both parametric and nonparametric approaches to estimate the distribution of critical gaps in the population of pedestrians. To estimate the model, we gather field data on crossing decisions and vehicle flows at three intersections in New Delhi. The estimates provide information about heterogeneity in critical gaps across pedestrians and intersections and permits simulation of the effect of changes in traffic light sequence (flows)on pedestran crossing behavior and waiting times.

Characterization of Aminoalkylcarbamoyl Cellulosic and Chitosan Derivatives for Use in Cosmetic Formulation.

Polymer and surfactant interactions have been a subject of intense research due to industrial applications utilizing a polymer-surfactant system, such as cosmetic formulation. A series of aminoalkylcarbamoyl cellulose derivatives were prepared from the amidation of methylcarboxymethyl cellulose. These derivatives were quaternized with either iodomethane, or hydroxypropyl trimethylammonium chloride, or epichlorohydrin and dimethylamine to yield polyquaternary ammonium salts. The focus of this dissertation is the characterization of a family of these compounds based on N,N\sp\prime,-dimethylethylene diamine. As these compounds are similar to Polyquaternium 10, a quaternized hydroxyethyl cellulose derivative, the solution properties have been characterized; antimicrobial activity and keratin affinity have been determined. Viscosity measurements indicated that derivatives containing a low number of cationic charges per graft and shorter graft length have the highest viscosity. Solubility studies showed that the polymers precipitate at their respective theoretical charge neutralization ratios at concentrations of polymer and anionic surfactant greater than 0.010%. At low polymer concentrations, a fixed concentration of sodium dodecyl sulfate was necessary to precipitate the complexes. The critical mole fraction of anionic surfactant necessary to cause precipitation of polymer-mixed surfactant micelle complexes was dependent upon polymer flexibility, charge density and polymer concentration. Changes in pyrene fluorescence intensity indicated that the micellar regions formed in these complexes were more hydrophilic than free micelles. Dynamic light scattering showed that systems containing Polyquaternium 10 were nearly monodisperse; whereas, systems containing our polymers were polydisperse. The Polyquaternium 10-mixed surfactant micelle complex exhibited a different temperature response than complexes formed with the aminoalkylcarbamoyl cellulose derivatives. Surface tension studies showed evidence of three interaction zones which were present regardless of polymer structure or charge density. Foam studies indicated that the system containing Polyquaternium 10 required more polymer to produce maximal foamability of SDS than either of our polymers. Bactericidal activity of the polymers against Escherichia coli, Staphylococcus aureus and Pseudomonas aeruginosa was determined. The results indicated that quaternary polymers may have a dual role in cosmetic products as preservatives and thickeners. Finally, scanning electron microscopy indicated that the binding of the polymers to the hair fibers was not uniform in all cases

Market structure, Regulation and the Speed of Mobile Network Penetration

The speed of market penetration (i.e. diffusion) is an important summary measure of how well the market works for potential consumers of a new product. This paper identifies the structural features associated with rapid diffusion of mobile telephony. We use a sample of thirty countries over the sixteen years in which average penetration rose from 2% to 97% of the population (earlier studies observed only the initial years of diffusion during which there was typically only one or two networks). We find a non-monotonic effect of market structure, with three firms maximising consumer uptake. Privatization and independent regulation are also important positive factors. Further results show that the market structure effect works only partially through the level of prices

Human hair and the impact of cosmetic procedures: a review on cleansing and shape-modulating cosmetics

Hair can be strategically divided into two distinct parts: the hair follicle, deeply buried in the skin, and the visible hair fiber. The study of the hair follicle is mainly addressed by biological sciences while the hair fiber is mainly studied from a physicochemical perspective by cosmetic sciences. This paper reviews the key topics in hair follicle biology and hair fiber biochemistry, in particular the ones associated with the genetically determined cosmetic attributes: hair texture and shape. The traditional and widespread hair care procedures that transiently or permanently affect these hair fiber features are then described in detail. When hair is often exposed to some particularly aggressive cosmetic treatments, hair fibers become damaged. The future of hair cosmetics, which are continuously evolving based on ongoing research, will be the development of more efficient and safer procedures according to consumers needs and concerns.Portuguese Foundation for Science and Technology (FCT) for providing Célia F. Cruz the grant for PhD studies (scholarship SFRH/BD/100927/2014) and Teresa Matamá the grant for post-doctoral research (SFRH/BPD/102153/2014). This work was also supported by FCT under the scope of the strategic funding of UID/BIO/04469/2013 and UID/BIA/04050/2013 units, COMPETE 2020 (POCI-01-0145-FEDER-006684andPOCI-01-0145-FEDER-007569) and under the Project RECI/BBB-EBI/0179/2012 (FCOMP-01-0124-FEDER-027462).info:eu-repo/semantics/publishedVersio

How Sales Taxes Affect Customer and Firm Behavior: The Role of Search on the Internet

When a multichannel retailer opens its first retail store in a state, the firm is obligated to collect sales taxes on all Internet and catalog orders shipped to that state. This article assesses how opening a store affects Internet and catalog demand. The authors analyze purchase behavior among customers who live far from the retail store but must now pay sales taxes on catalog and Internet purchases. A comparable group of customers in a neighboring state serves as a control. The results show that Internet sales decrease significantly, but catalog sales are unaffected. Further investigation indicates that the difference in these outcomes is partly attributable to the ease with which customers can search for lower prices at competing retailers. The authors extend the analysis to a panel of multichannel firms and show that retailers that earn a large proportion of their revenue from direct channels avoid opening a first store in high-tax states. They conclude that current U.S. sales taxes laws have significant effects on both customer and firm behavior

Synthesis and Mechanistic Study of Mild-Mediated C-H Metal Activation Reactions

Metal-catalyzed C-H activation and functionalization have become a widely researched method in synthetic organic chemistry, with a large but largely untapped potential for pharmaceutical and medicinal applications. Challenges remain, in particular with regard to regioselectivity, since C-H bonds are ubiquitous in organic compounds. The goal of this project is to use FTIR spectroscopy as a tool with high sensitivity and time-resolution to study the mechanism of synthesized C-H activation reactions

Profile kompetencyjne menedżerów sektora publicznego Streszczenie

Although usually presented as a simple process that can be accomplished in a few steps, the building of a competency model for managers is an arduous and time-consuming and the real testing of managers’ competency profile is not easy. In a globalised world full of advantages and disadvantages we operate within complex systems filled with interdependencies that are hard to reveal and non-linear responses to the disruptions. These complex systems tend to generate uncontrolled chain reactions, which reduce or even eliminate predictability. If we add on continuously emerging new problems and social, economic, technological, and cultural requirements we are faced with a situation which requires managers to go beyond their specialty or beyond skills they have acquired through education and experience. The goal of the paper was to outline competency profiles of managers from the public sectorand try to identify the most suitable competencies for efficient management in the future. Theoretical competency models are presented and the most expected manager competency models for effective management of public sector institutions are defined.An investigation into competency profiles of managers of public healthcare institutions is proposed. Considerations conducted in this paper about the scope of managers’ competencies in some areas of the public sector and tasks entrusted to them have demonstrated how big responsibility rests on managers of public sector units when it comes to their regular scope of competencies, its modification and facing new challenges.Budowanie modelu kompetencyjnego menedżerów, jakkolwiek prosto zazwyczaj przedstawiane w kilku krokach, jest procesem żmudnym i czasochłonnym, a rzeczywiste sprawdzenie profilu kompetencji menedżerów niełatwe. W globalnym świecie pełnym zalet i wad funkcjonujemy w obrębie złożonych systemów, pełnych wzajemnych, trudnych do wykrycia współzależności oraz nieliniowych reakcji na zakłócenia porządku. Te złożone systemy mają skłonność do wytwarzania niekontrolowanych reakcji łańcuchowych, które zmniejszają, a nawet eliminują przewidywalność. Gdy dołączą się do tego ciągle nowe problemy i wymagania społeczno-ekonomiczne, technologiczne i kulturowe, mamy do czynienia z sytuacją, która stawia przed menedżerami wymagania wykraczające poza to, co jest ich specjalnością, czy poza nabyte przez nich w swoim czasie w wyniku edukacji i doświadczenia umiejętności.W tekście zaprezentowano teoretyczne modele kompetencji oraz zdefiniowano najbardziej oczekiwane profile kompetencyjne menedżerów dla efektywnego zarządzania instytucjami sektora publicznego.Zaproponowano przeprowadzenie badań profili kompetencyjnych menedżerów publicznych podmiotów leczniczych. Przeprowadzone w pracy rozważania o zakresie kompetencji menedżerów części sektora publicznego i zadań, jakie pozostają w obszarze ich obowiązków, pokazały, jak wielka odpowiedzialność spoczywa na osobach zarządzających podmiotami sektora publicznego zarówno w zakresie realizacji dotychczasowych zadań ich modyfikacji, jak i podejmowania nowych wyzwań

Authority In Hooker's Polity..

PhDBritish and Irish literatureUniversity of Michigan, Horace H. Rackham School of Graduate Studieshttp://deepblue.lib.umich.edu/bitstream/2027.42/189425/2/7627538.pd