Model of Spatial Market Areas and Transportation Demand

2005 ◽  
Vol 1909 (1) ◽  
pp. 31-38
Author(s):  
Kevin E. Henrickson ◽  
Wesley W. Wilson
Keyword(s):  
Significant Influence ◽  
Spatial Competition ◽  
Demand Elasticity ◽  
Strong Argument ◽  
Transportation Demand ◽  
Geographic Space ◽  
Market Areas ◽  
Derived Demand

A model of transportation demand and the interrelated supply decisions of agricultural shippers is derived over a geographic space. These shippers use prices to procure grain and to make output, mode, and market decisions. Each decision is affected by the characteristics of the region and the level of spatial competition between the shipper and its rivals. All of these factors are integrated into the model of derived demand and spatial competition. The model is applied to data that represent barge elevators on the upper Mississippi and Illinois Rivers to estimate transportation demands and gathering areas. The results provide demand elasticity estimates for annual volumes between −1.4 and −1.9, which are sizably larger than previous estimates of similar traffic. The results also indicate that inbound transportation rates to the barge shipper as well as distance to the nearest competitor have a significant influence on annual volumes. A second model, explaining the size of the market areas of elevators, is also estimated. The rates of alternative modes that compete for barge traffic as well as distance to the nearest competitor influence market areas. The results provide for a strong argument that transportation demands are elastic and that spatial market areas vary substantially with transportation rates.

Estimating Price and Service Elasticity of Urban Transportation Demand with Stated Preference Technique: Case in Korea

2003 ◽  
Vol 1839 (1) ◽  
pp. 167-172 ◽  
Author(s):  
Sungwon Lee ◽  
Yeong Heok Lee ◽  
Jee Hyung Park
Keyword(s):  
Travel Demand ◽  
Stated Preference ◽  
Demand Management ◽  
Parameter Estimate ◽  
Demand Elasticity ◽  
Fuel Price ◽  
Travel Demand Management ◽  
Passenger Car ◽  
Transportation Demand ◽  
Car Travel

Price and service elasticities of passenger car travel are estimated using stated preference and sample enumeration methodology. Moreover, the effects of hypothetical travel demand management policies are analyzed by changes on modal share using the elasticity estimates. The elasticity of passenger car travel with fuel price is estimated to be within the range of −0.078 to −0.171. The parameter estimate of the fare variable is estimated to be statistically insignificant in every subgroup of car users. This finding suggests that fare policies are relatively ineffective for increasing transit modal shares in Korea. Meanwhile, car users' responsiveness to changes in parking costs is estimated to be much higher than for fuel cost. This suggests that parking regulations or pricing policies may be effective in reducing travel by passenger car. The elasticity with in-vehicle time, which is a key attribute of public transport amenities, is estimated to be particularly high, implying that policy measures such as introducing express buses or express urban trains could be effective in reducing passenger car travel. The demand elasticity of service levels of mass transit represented by the degree-of-crowdedness proxy turns out to be very high. Reducing crowdedness in public transit can be very effective in attracting more passengers, or at least in retaining current patronage.

What is Transportation For?

2019 ◽  
pp. 18-34
Author(s):  
Jonathan Levine ◽  
Joe Grengs ◽  
Louis A. Merlin
Keyword(s):  
Land Use ◽  
Land Use Planning ◽  
Land Use Patterns ◽  
Transportation Demand ◽  
Use Patterns ◽  
Demand Curves ◽  
Important Challenge ◽  
History Of ◽  
Consensus View ◽  
Derived Demand

This chapter traces the history of the derived-demand concept, its application to the transportation context, and an important challenge to the derived view of transportation demand. The derived-demand concept, which underpins the logic of accessibility in transportation and land-use planning, originated in realms entirely removed from transportation. The derived-demand term was coined in 1895 by the economist Alfred Marshall, who used it to describe the demand curves for goods that were intermediate to the consumption or production of other goods. However, the first application of Marshall's derived-demand concept to transportation may have come four decades later in Michael Bonavia's 1936 book The Economics of Transport. The derived-demand concept in transportation was developed further by Robert Mitchell and Chester Rapkin, who were interested in forecasting demand for transportation on the basis of land-use patterns across a metropolitan area. Ultimately, the consensus view that transportation demand is mostly derived is not an absolute truth but, rather, is based on the view that transportation is most usefully viewed—in most circumstances and for most trips—as one means to an end, rather than an end in itself.

Reilly's Challenge: New Laws of Retail Gravitation Which Define Systems of Central Places

1978 ◽  
Vol 10 (2) ◽  
pp. 185-219 ◽  
Author(s):  
M Batty
Keyword(s):  
Spatial Information ◽  
Spatial Competition ◽  
Spatial Interaction ◽  
Market Area ◽  
Urban Hierarchy ◽  
Spatial Interaction Models ◽  
Market Areas ◽  
Definition Of ◽  
Relationship Of ◽  
New Evidence

This paper attempts a reformulation and generalisation of Reilly's (1931) law of retail gravitation. Reilly himself challenged workers in the field to produce new evidence which would refute or strengthen his law, and developments in spatial-interaction theory during the last decade are used here in taking up this challenge. A critique of Reilly's law sets the scene: By adopting a gravity model more general than the Newtonian model used by Reilly, it is shown how the limitations of the law with respect to hierarchy, spatial competition, locational size, and the symmetry of trade flows, are overcome. In particular the notion of Reilly's law as a special case of the market-area analysis originating from Fetter (1924) and Hotelling (1929) is demonstrated in terms of a theory of the breakpoint implying spatial price–cost indifference. Another approach, through entropy-maximisation and its dual problem, leads to similar conclusions with regard to prices, and it also serves to introduce multicentred spatial competition. These ideas are then generalised in several ways: through notions about the influence of prior spatial information, through concepts of consumer as well as producer market areas or fields, and through the implications of the analysis for the family of spatial-interaction models. A speculation on the relationship of price differentials to Tobler's (1975) interaction winds is made, and the paper is concluded with an application of these models to the definition of an urban hierarchy in the Reading subregion.

scholarly journals International Real Estate Review

2019 ◽  
Vol 22 (4) ◽  
pp. 535-570
Author(s):  
Chongyu Wang ◽  
◽  
Jeffrey P. Cohen ◽  
John L. Glascock ◽  
◽  
...  
Keyword(s):  
Spatial Econometrics ◽  
Financial Distress ◽  
Cost Minimization ◽  
Spatial Competition ◽  
A Priori ◽  
Financial Capital ◽  
Crowding Out ◽  
Stock Liquidity ◽  
Geographic Space ◽  
Capital Demand

The question of whether REITs compete for scarce capital across geographic space is deserving of attention. In this study, we consider the issue of spatial competition among REITs across U.S. states in terms of the degree of interdependence in financial capital demand. First, we motivate the issue with a theoretical model of cost minimization by using a representative REIT in a given U.S. state and demonstrate that a priori, it is unclear whether the capital demand of a REIT depends on that of the REITs in other states. Then we use spatial econometrics techniques and find empirically that REITs compete for financial capital with REITs in other states. We also find evidence of feedback (or indirect) effects, thus implying amplified crowding out of financial capital when other REITs in nearby states increase financial capital demand. Our findings are aligned with the predation hypothesis, which suggests that REIT managers might exploit the financial distress of neighboring REITs and/or investors as an opportunity to steal their market share. Another key contribution of this study is that we focus on capital liquidity as opposed to stock liquidity.

Influence of nascent polypeptide positive charges on translation dynamics

2020 ◽  
Vol 477 (15) ◽  
pp. 2921-2934
Author(s):  
Rodrigo D. Requião ◽  
Géssica C. Barros ◽  
Tatiana Domitrovic ◽  
Fernando L. Palhano
Keyword(s):  
Mrna Decay ◽  
Translation Termination ◽  
Published Data ◽  
Translation Efficiency ◽  
Amino Acid Residues ◽  
High Concentration ◽  
Strong Argument ◽  
Translation Arrest ◽  
Exit Tunnel ◽  
Positively Charged

Protein segments with a high concentration of positively charged amino acid residues are often used in reporter constructs designed to activate ribosomal mRNA/protein decay pathways, such as those involving nonstop mRNA decay (NSD), no-go mRNA decay (NGD) and the ribosome quality control (RQC) complex. It has been proposed that the electrostatic interaction of the positively charged nascent peptide with the negatively charged ribosomal exit tunnel leads to translation arrest. When stalled long enough, the translation process is terminated with the degradation of the transcript and an incomplete protein. Although early experiments made a strong argument for this mechanism, other features associated with positively charged reporters, such as codon bias and mRNA and protein structure, have emerged as potent inducers of ribosome stalling. We carefully reviewed the published data on the protein and mRNA expression of artificial constructs with diverse compositions as assessed in different organisms. We concluded that, although polybasic sequences generally lead to lower translation efficiency, it appears that an aggravating factor, such as a nonoptimal codon composition, is necessary to cause translation termination events.

Perception of Autonomy and Connectedness Prior to the Onset of Anorexia Nervosa and Bulimia Nervosa

2012 ◽  
Vol 40 (1) ◽  
pp. 61-68 ◽  
Author(s):  
Julia Huemer ◽  
Maria Haidvogl ◽  
Fritz Mattejat ◽  
Gudrun Wagner ◽  
Gerald Nobis ◽  
...  
Keyword(s):  
Anorexia Nervosa ◽  
Risk Factor ◽  
Bulimia Nervosa ◽  
Family Environment ◽  
Significant Influence ◽  
Diagnostic Interview ◽  
Individual Autonomy ◽  
Mothers And Fathers ◽  
Image Test ◽  
Restrictive Type

Objective: This study examines retrospective correlates of nonshared family environment prior to onset of disease, by means of multiple familial informants, among anorexia and bulimia nervosa patients. Methods: A total of 332 participants was included (anorexia nervosa, restrictive type (AN-R): n = 41 plus families); bulimic patients (anorexia nervosa, binge-purging type; bulimia nervosa: n = 59 plus families). The EATAET Lifetime Diagnostic Interview was used to establish the diagnosis; the Subjective Family Image Test was used to derive emotional connectedness (EC) and individual autonomy (IA). Results: Bulimic and AN-R patients perceived significantly lower EC prior to onset of disease compared to their healthy sisters. Bulimic patients perceived significantly lower EC prior to onset of disease compared to AN-R patients and compared to their mothers and fathers. A low family sum – sister pairs sum comparison – of EC had a significant influence on the risk of developing bulimia nervosa. Contrary to expectations, AN-R patients did not perceive significantly lower levels of IA compared to their sisters, prior to onset of disease. Findings of low IA in currently ill AN-R patients may represent a disease consequence, not a risk factor. Conclusions: Developmental child psychiatrists should direct their attention to disturbances of EC, which may be present prior to the onset of the disease.

Comparative Labelling and Biokinetic Studies of 99mTc-EDTA(Sn) and 99mTc-DTPA(Sn)

1977 ◽  
Vol 16 (01) ◽  
pp. 30-35 ◽  
Author(s):  
N. Agha ◽  
R. B. R. Persson
Keyword(s):  
Complex Formation ◽  
Significant Influence ◽  
Room Temperature ◽  
Ph Value ◽  
Maximum Activity ◽  
Reduction Step ◽  
Labelling Yield ◽  
Different Temperatures ◽  
Kinetics Of

SummaryGelchromatography column scanning has been used to study the fractions of 99mTc-pertechnetate, 99mTcchelate and reduced hydrolyzed 99mTc in preparations of 99mTc-EDTA(Sn) and 99mTc-DTPA(Sn). The labelling yield of 99mTc-EDTA(Sn) chelate was as high as 90—95% when 100 μmol EDTA · H4 and 0.5 (Amol SnCl2 was incubated with 10 ml 99mTceluate for 30—60 min at room temperature. The study of the influence of the pH-value on the fraction of 99mTc-EDTA shows that pH 2.8—2.9 gave the best labelling yield. In a comparative study of the labelling kinetics of 99mTc-EDTA(Sn) and 99mTc- DTPA(Sn) at different temperatures (7, 22 and 37°C), no significant influence on the reduction step was found. The rate constant for complex formation, however, increased more rapidly with increased temperature for 99mTc-DTPA(Sn). At room temperature only a few minutes was required to achieve a high labelling yield with 99mTc-DTPA(Sn) whereas about 60 min was required for 99mTc-EDTA(Sn). Comparative biokinetic studies in rabbits showed that the maximum activity in kidneys is achieved after 12 min with 99mTc-EDTA(Sn) but already after 6 min with 99mTc-DTPA(Sn). The long-term disappearance of 99mTc-DTPA(Sn) from the kidneys is about five times faster than that for 99mTc-EDTA(Sn).

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