bluuebunny/crossref_metadata_2025 huggingface dataset:
The adult human pubic symphysis: a systematic review
Authors: Becker Ines , Woodley Stephanie J. , Stringer Mark D.
Published: September 2010

The pubic symphysis is a unique joint consisting of a fibrocartilaginous disc sandwiched between the articular surfaces of the pubic bones. It resists tensile, shearing and compressive forces and is capable of a small amount of movement under physiological conditions in most adults (up to 2 mm shift and 1° rotation). During pregnancy, circulating hormones such as relaxin induce resorption of the symphyseal margins and structural changes in the fibrocartilaginous disc, increasing symphyseal width and mobility. This systematic review of the English, German and French literature focuses on the normal anatomy of the adult human pubic symphysis. Although scientific studies of the joint have yielded useful descriptive data, comparison of results is hampered by imprecise methodology and/or poorly controlled studies. Several aspects of the anatomy of the pubic symphysis remain unknown or unclear: the precise attachments of surrounding ligaments and muscles; the arrangement of connective tissue fibres within the interpubic disc and the origin, structure and function of its associated interpubic cleft; the biomechanical consequences of sexual dimorphism; potential ethnic variations in morphology; and its precise innervation and blood supply. These deficiencies hinder our understanding of the normal form and function of the joint, which is particularly relevant when attempting to understand the mechanisms underlying pregnancy‐related pubic symphyseal pain, a neglected and relatively common cause of pubic pain. A better understanding of the normal anatomy of the human pubic symphysis should improve our understanding of such problems and contribute to better treatments for patients suffering from symphyseal pain and dysfunction.
A new tool for the validation of umbilical cord acid–base data
Authors: Kro GAB , Yli BM , Rasmussen S , Norèn H , Amer‐Wåhlin I , Saugstad OD , Stray‐Pedersen B , Rosén KG
Published: September 2010

Please cite this paper as: Kro G, Yli B, Rasmussen S, Norèn H, Amer‐Wåhlin I, Didrik Saugstad O, Stray‐Pedersen B, Rosén K. A new tool for the validation of umbilical cord acid–base data. BJOG 2010;117:1544–1552.

Objective  To identify the distribution of carbon dioxide tension (pCO2) relative to pH in validated umbilical cord acid–base data.

Design  Observational study.

Setting  European hospital labour wards.

Population  Data for 36 432 term newborns were obtained from three sources: two trials of fetal monitoring with electrocardiography (ECG; the Swedish randomised controlled trial and the European Union Fetal ECG trial) and data from Mölndal Hospital.

Methods  From the total study population, cases with missing values or obvious typing errors were excluded. The remaining data were validated based on specified criteria. Percentiles of arterial pCO2 by pH were calculated using multilevel regression modelling.

Main outcome measures  Umbilical cord pH, pCO2 and base deficit.

Results  Acid–base values were considered invalid in one out of seven cases. Percentiles for arterial pCO2 corresponding to specified values of arterial pH were developed from the validated data of 26 690 cases.

Conclusions  Percentiles for arterial pCO2 for a specified arterial pH can be used as a tool to identify cases with erroneously low pCO2 values, and thus avoid an incorrect interpretation of the newborn’s acid–base status.
FUNCTIONAL AND BIOCHEMICAL MODIFICATIONS OF LUNG β‐ADRENORECEPTORS AFTERIN VIVODESENSITIZATION: PREVENTION BY INDOMETHACIN
Authors: FANO M. , ABBRACCHIO MARIA PIA , CATTABENI F. , DAFFONCHIO LUISA , HERNANDEZ ALICIA , OMINI C.
Published: September 2010

Desensitization of lung β‐adrenoreceptors induced by 4 dayin vivoisoprenaline administration to rats has been investigated both from a functional and a biochemical viewpoint.

Chronic isoprenaline treatment significantly reduced the relaxing activity of the β‐agonist when testedex vivoin lung parenchymal strips and also impaired the adenylate‐cyclase system. Moreover, the desensitization procedure decreased by about 30% β‐adrenoreceptor number.

In vivoindomethacin treatment prevented the loss of pharmacological responsiveness of the tissue to isoprenaline and restored basal adenylate‐cyclase activity.

These data indicate thatin vivoisoprenaline administration actually leads to pulmonary β‐adrenoreceptor desensitization. The involvement of arachidonic acid metabolites in this phenomenon is also discussed.
TARGET SITES FOR ANTICHOLINESTERASES ON THE VENTRAL SURFACE OF THE MEDULLA OBLONGATA: HYPOTENSION ELICITED BY ORGANOPHOSPHORUS AGENTS
Authors: EDERY H. , GEYER M. A. , TAYLOR P. , BERMAN H. A.
Published: September 2010

Sensitivity of the ventral surface of the medulla oblongata to organophorus agents, oxime reactivators, and muscarinic antagonists was examined in order to delineate sites of cholinergic activity in the central nervous system. The exposed ventral surface of the medulla oblongata in anaesthetized cats was treated with the organophosphorus anticholinesterase agents soman and (7‐nitro‐2‐oxa‐1,3‐diazole) aminopentyl methylphosphonofluoridate (NBD‐AP‐MFP), a fluorescent active centre‐selective probe of acetylcholinesterase.

Topical application of soman (1–5 μg) or NBD‐AP‐MPF (5–120 μg) elicited a profound (80–90 mm Hg), long‐lasting (0.5‐3 h), dose‐dependent vasodepression with only minor changes in heart rate and respiration.

The vasodepression was rapidly reversed (7–10 min) upon topical application of muscarinic antagonists (atropine methylnitrate, atropine sulphate) and the bisquaternary oxime HI‐6; systemic administration was without effect.

Reversal of the hypotension by HI‐6 occurred irrespective of whether the organophosphorus agent was NBD‐AP‐MPF, which forms conjugates with acetylcholinesterase that undergo no aging, or soman, which forms conjugates that undergo extensive aging rendering the enzyme refractory to oxime reactivation.

Hence, oxime efficacy for reversal of the physiologic hypotension was not dependent solely on the fraction reactivatable enzyme.

By virtue of the fluorescence distribution of NBD‐AP‐MPF the chemosensitive sites were estimated to reside no deeper than 50 microns into the medulla oblongata, providing a direct indication for localization of the chemosensitive cells on the superficial surface.
POSSIBLE INTERACTION OF CHOLINERGIC NERVES WITH TWO DIFFERENT (PRE AND POST) SITES OF THE NEUROMUSCULAR JUNCTION IN GUINEA‐PIG VAS DEFERENS
Authors: FUKUSHI Y. , WAKUI M.
Published: September 2010

Effects of various drugs on the mechanical responses of the longitudinal smooth muscle of guinea‐pig vas deferens evoked by ACh and field nerve stimulation were examined.

ACh (28–280, μM) produced a contraction consisting of two phases. The first phase of the contraction was suppressed by guanethidine and by nicotinic antagonists. The second phase was suppressed only by atropine. Both phases were unaffected by TTX or prazosin.

Field stimulation (0.1 msec, 40 Hz) evoked contractions which also consisted of two (early and late) phases. Guanethidine (0.1‐1 μM) suppressed both phases whilst prazosin (1 μM) suppressed only the late phase.

Atropine (0.1 μM) suppressed both phases whilst physostigmine (5 μM) potentiated both phases of field stimulation‐evoked contractions.

Pentolinium suppressed both phases of field stimulation‐evoked contractions at low concentrations (2–10 μM), but potentiated them at a higher concentration (100 μM).

dTC at a low concentration (0.5 mUM) suppressed the early phase, but slightly enhanced the late phase of field stimulation responses. At a higher concentration (20 μM), dTC potentiated both phases of the response.

Pentolinium and dTC did not affect the contractions induced by 90 mM‐K ions, ATP or NA.

These results suggest that cholinergic nerves possess an excitatory action not only directly at the smooth muscle but also at the noradrenergic nerve terminals. The role of each receptor is discussed further.
Offspring quality and the evolution of cainism
Authors: SIMMONS ROBERT
Published: September 2010

Obligate siblicide, known as ‘cainism’ in large raptors, is a taxonomically widespread avian phenomenon that remains inexplicable as a simple consequence of food stress: two young can be raised to independence in experimentally manipulated nests, and food supplements do not decrease sibling aggression.

A review of the Falconiformes identified 23 species in which obligate and facultative cainism is regular. All species have small clutches and deferred acquisition of adult plumage. Obligate cainists in particular are large, long‐lived species characterized by extreme subadult mortality and intense competition for breeding sites. Hence, it can be suggested that early sibling conflict, in the absence of food stress, is the end result of selection for quality (survival) and competitive ability. Cain's domination or killing of Abel insures (1) an increase in Cain's chances of survival through the high‐risk, pre‐breeding period via improved nestling weight gain, and/or (2) domination of surviving sibs, enhancing Cain's competitive abilities and thereby increasing the probability of achieving breeding status. Only among long‐lived species can the benefits of enhanced survival and competitive ability outweigh the major costs of sibling loss.

Facultative cainists, which in more than 10% of cases raise more than one young (despite aggression and sibling hierarchies), not only lay larger, more variable clutches, but on average attain adult plumage earlier than obligate cainists. Their shorter lives and higher population turnovers are consistent with their less extreme siblicidal tendencies. Similar life‐history traits and cainistic habits in other avian orders parallel those in the Falconiformes, indicating several independent evolutionary pathways to cainism.

Retention of the second egg by obligate cainists, usually explained as insurance against failure, may instead allow parents adaptively to track population stability. Thus when breeding places are numerous (habitat saturation and competition low), parents laying two eggs and rearing two young may achieve greater fitness than single‐young parents. When populations become saturated (competition high), selection should favour high‐quality, competitive young and levels of siblicide should increase. A proximate mechanism is proposed linking population saturation with the incidence of cainism, based on demonstrable population characteristics found in several long‐lived species.
Inhibition of microsomal prostaglandin E2synthase‐1 as a molecular basis for the anti‐inflammatory actions of boswellic acids from frankincense
Authors: Siemoneit U , Koeberle A , Rossi A , Dehm F , Verhoff M , Reckel S , Maier TJ , Jauch J , Northoff H , Bernhard F , Doetsch V , Sautebin L , Werz O
Published: September 2010

BACKGROUND AND PURPOSEFrankincense, the gum resin derived fromBoswelliaspecies, showed anti‐inflammatory efficacy in animal models and in pilot clinical studies. Boswellic acids (BAs) are assumed to be responsible for these effects but their anti‐inflammatory efficacyin vivoand their molecular modes of action are incompletely understood.

EXPERIMENTAL APPROACHA protein fishing approach using immobilized BA and surface plasmon resonance (SPR) spectroscopy were used to reveal microsomal prostaglandin E2synthase‐1 (mPGES1) as a BA‐interacting protein. Cell‐free and cell‐based assays were applied to confirm the functional interference of BAs with mPGES1. Carrageenan‐induced mouse paw oedema and rat pleurisy models were utilized to demonstrate the efficacy of defined BAsin vivo.

KEY RESULTSHuman mPGES1 from A549 cells orin vitro‐translated human enzyme selectively bound to BA affinity matrices and SPR spectroscopy confirmed these interactions. BAs reversibly suppressed the transformation of prostaglandin (PG)H2to PGE2mediated by mPGES1 (IC50 = 3–10 µM). Also, in intact A549 cells, BAs selectively inhibited PGE2generation and, in human whole blood, β‐BA reduced lipopolysaccharide‐induced PGE2biosynthesis without affecting formation of the COX‐derived metabolites 6‐keto PGF1αand thromboxane B2. Intraperitoneal or oral administration of β‐BA (1 mg·kg−1) suppressed rat pleurisy, accompanied by impaired levels of PGE2and β‐BA (1 mg·kg−1, given i.p.) also reduced mouse paw oedema, both induced by carrageenan.

CONCLUSIONS AND IMPLICATIONSSuppression of PGE2formation by BAs via interference with mPGES1 contribute to the anti‐inflammatory effectiveness of BAs and of frankincense, and may constitute a biochemical basis for their anti‐inflammatory properties.
Calcium signalling mediated through α7 and non‐α7 nAChR stimulation is differentially regulated in bovine chromaffin cells to induce catecholamine release
Authors: del Barrio Laura , Egea Javier , León Rafael , Romero Alejandro , Ruiz Ana , Montero Mayte , Álvarez Javier , López Manuela G.
Published: September 2010

BACKGROUND AND PURPOSECa2+signalling and exocytosis mediated by nicotinic receptor (nAChR) subtypes, especially the α7 nAChR, in bovine chromaffin cells are still matters of debate.

EXPERIMENTAL APPROACHWe have used chromaffin cell cultures loaded with Fluo‐4 or transfected with aequorins directed to the cytosol or mitochondria, several nAChR agonists (nicotine, 5‐iodo‐A‐85380, PNU282987 and choline), and the α7 nAChR allosteric modulator PNU120596.

KEY RESULTSMinimal [Ca2+]ctransients, induced by low concentrations of selective α7 nAChR agonists and nicotine, were markedly increased by the α7 nAChR allosteric modulator PNU120596. These potentiated responses were completely blocked by the α7 nAChR antagonist α‐bungarotoxin (α7‐modulated‐response). Conversely, high concentrations of the α7 nAChR agonists, nicotine or 5‐iodo‐A‐85380 induced larger [Ca2+]ctransients, that were blocked by mecamylamine but were unaffected by α‐bungarotoxin (non‐α7 response). [Ca2+]cincreases mediated by α7 nAChR were related to Ca2+entry through non‐L‐type Ca2+channels, whereas non‐α7 nAChR‐mediated signals were related to L‐type Ca2+channels; Ca2+‐induced Ca2+‐release contributed to both responses. Mitochondrial involvement in the control of [Ca2+]ctransients, mediated by either receptor, was minimal. Catecholamine release coupled to α7 nAChRs was more efficient in terms of catecholamine released/[Ca2+]c.

CONCLUSIONS AND IMPLICATIONS[Ca2+]cand catecholamine release mediated by α7 nAChRs required an allosteric modulator and low doses of the agonist. At higher agonist concentrations, the α7 nAChR response was lost and the non‐α7 nAChRs were activated. Catecholamine release might therefore be regulated by different nAChR subtypes, depending on agonist concentrations and the presence of allosteric modulators of α7 nAChRs.
The homeostasis model assessment of the insulin resistance score is not predictive of a sustained virological response in chronic hepatitis C patients
Authors: Fattovich Giovanna , Covolo Loredana , Pasino Michela , Perini Eleonora , Rossi Luigi , Brocco Giorgio , Guido Maria , Cristofori Chiara , Belotti Caterina , Puoti Massimo , Gaeta Giovanni Battista , Santantonio Teresa , Raimondo Giovanni , Bruno Raffaele , Minola Eliseo , Negro Francesco , Donato Francesco ,   The Italian Hepatitis C Cohort Study (ITAHECS) Collaborative Group
Published: September 2010

Objectives:To investigate the independent association between the homeostasis model assessment of the insulin resistance (HOMA‐IR) score and rapid virological response (RVR) and sustained virological response (SVR) in chronic hepatitis C (CHC).

Methods:Observational prospective cohort study of 412 CHC patients [59% males; mean age 45 years; genotype 1 (44%), 2 (32%), 3 (19%) and 4 (5%)] treated with pegylated interferon α plus ribavirin.

Results:A HOMA‐IR ≥2.0 was present in 49% and a metabolic syndrome in 4% of patients. By multivariate analysis, independent predictors of SVR were the lack of advanced fibrosis (≥F3) in genotype 1 and a lower body mass index in genotype 3 patients. In the subgroup of patients in whom HCV‐RNA was evaluated at week 4 (n=281), independent predictors of RVR were HCV‐RNA <700 000 IU/ml, age <40 years and lower aspartate aminotransferase:alanine aminotransferase ratio in genotype 1 and baseline HOMA‐IR ≤2 in genotype 3 patients. No predictive factor of RVR was identified among genotype 2 patients. RVR was the strongest predictor of SVR among genotype 1 or 3 patients.

Conclusions:In this series of treatment‐naïve, Caucasian CHC patients at a low risk for the metabolic syndrome, HOMA‐IR is not a predictor of SVR, irrespective of the HCV genotype, although it may predict RVR in genotype 3 infection.
Does the anti‐hypertensive drug clonidine affect the short‐term variation in CTG recordings?
Authors: THORNTON Charlene E. , MAKRIS Angela , TOOHER Jane M. , OGLE Robert F. , HENNESSY Annemarie
Published: September 2010

Background:  Cardiotocographic (CTG) recordings of the fetal heart remain standard obstetric practice among hypertensive women. Changes in the short‐term variation (STV) in the fetal heart are often attributed to the effect of anti‐hypertensive medications, regardless of the fact that this principle has never been validated.

Aim:  To assess the STV of CTG recordings pre‐ and post‐ the anti‐hypertensive medication, clonidine.

Methods:  Forty hypertensive pregnant women, already receiving the anti‐hypertensive clonidine, were recruited. The CTGs were conducted pre‐ and post‐dose administration. The CTGs were assessed by the Sonicaid Team® automated CTG analysis (Oxford Instruments, UK) to avoid CTG assessor bias. Baseline fetal heart rate (FHR) (delta change from pre‐ and post‐dose) and STV were compared using spss v.14® utilising Student t‐tests.

Results:  No statistical difference was found in the pre‐ and post‐baseline FHRs (P = 0.48). The mean delta baseline heart rate before and after drug administration was −0.54 bpm. The STV of the CTGs recorded pre‐ and post‐clonidine dose was also not affected by administration of the drug (P = 0.34). The mean delta STV before and after drug administration was 0.39 ms. Two women received betamethasone 12 mg intramuscularly within the 12‐h period prior to CTG recordings to enhance fetal lung maturity. The mean STV for the fetuses of these women pre‐drug was 4.8 ms and 13.2 ms post‐administration. This was the largest delta seen in all STVs recorded in this dataset.

Conclusion:  The anti‐hypertensive drug clonidine does not alter baseline FHRs or affect the STV of the FHR in hypertensive pregnant women.
Fear of Falling After Hip Fracture: A Systematic Review of Measurement Instruments, Prevalence, Interventions, and Related Factors
Authors: Visschedijk Jan , Achterberg Wilco , van Balen Romke , Hertogh Cees
Published: September 2010

The objective of this review was to systematically describe and analyze fear of falling (FoF) in patients after a hip fracture, focusing on measurement instruments for FoF, the prevalence of FoF, factors associated with FoF, and interventions that may reduce FoF. Fifteen relevant studies were found through a systematic literature review, in which the PubMed, Embase, PsychINFO, and CINAHL databases were searched. Some of these studies indicated that 50% or more of patients with a hip fracture suffer from FoF, although adequate instruments still have to be validated for this specific group. FoF was associated with several negative rehabilitation outcomes, such as loss of mobility, institutionalization, and mortality. FoF was also related to less time spent on exercise and an increase in falls, although knowledge about risk factors, the prevalence over a longer time period, and the exact causal relations with important health outcomes is limited. Most studies suffer from selection bias by excluding patients with physical and cognitive disorders. Hence, more research is required, including in patients who are frail and have comorbidities. Only when knowledge such as this becomes available can interventions be implemented to address FoF and improve rehabilitation outcomes after a hip fracture.
Sleep Duration and Mortality According to Health Status in Older Adults
Authors: Mesas Arthur Eumann , López‐García Esther , León‐Muñoz Luz Ma , Guallar‐Castillón Pilar , Rodríguez‐Artalejo Fernando
Published: September 2010

OBJECTIVES: To examine the association between usual sleep duration and mortality according to physical and mental health status in older adults.

DESIGN: Prospective study conducted from 2001 to 2008.

SETTING: Community‐based study.

PARTICIPANTS: Cohort study of 3,820 persons representative of the noninstitutionalized population aged 60 and older in Spain.

MEASUREMENTS: Sleep duration was self‐reported at baseline. Analyses were performed using Cox regression and adjusted for the main confounders. The analyses were then stratified according to numerous indicators of health status.

RESULTS: During follow‐up, 897 persons died. Mortality was higher in those who slept 8 hours (relative risk (RR)=1.34, 95% confidence interval (CI)=1.02–1.76), 9 hours (RR 1.48, 95% CI=1.12–1.96), 10 hours (RR 1.73, 95% CI=1.30–2.29) and 11 hours or more (RR 1.66, 95% CI=1.23–2.24) than in those who slept 7 hours (P for trend <.001). The association between long sleep duration (≥10 vs 7 hours) and mortality was observed even in persons with good health status: optimal perceived health, good cognitive function (Mini‐Mental State Examination score >27), no depression, quality of life better than the cohort median (Medical Outcomes Study 36‐item Short Form Survey Physical Component Summary score ≥46 and Mental Component Summary score ≥52), and without disability in instrumental activities of daily living. Sleeping 6 hours or less was not associated with higher mortality than sleeping 7 hours in persons with good health status.

CONCLUSION: Self‐reported sleep duration was associated with 7‐year mortality in this cohort of older adults, even when adjusted for health status. Further research is needed to determine the mechanisms and clinical implications of these findings.
Three‐Regime Asymmetric STAR Modeling and Exchange Rate Reversion
Authors: CERRATO MARIO , KIM HYUNSOK , MACDONALD RONALD
Published: September 2010

The breakdown of the Bretton Woods system and the adoption of generalized floating exchange rates ushered in a new era of exchange rate volatility and uncertainty. This increased volatility leads economists to search for economic models able to describe observed exchange rate behavior. In the present paper, we propose more general STAR transition functions that encompass both threshold nonlinearity and asymmetric effects. Our framework allows for a gradual adjustment from one regime to another and considers threshold effects by encompassing other existing models, such as TAR models. We apply our methodology to three different exchange rate data sets: one for developing countries and official nominal exchange rates, the second for emerging market economies using black market exchange rates, and the third for OECD economies.
The Evaluation of Urban Public Facility Location: An Alternative to Benefit‐Cost Analysis
Authors: Austin C. Murray
Published: September 2010

This paper attempts to overcome some specific problems which exist with the use of benefit‐cost analysis in evaluating the impact of public facilities. The concepts developed explicitly recognize the importance of the spatial distribution of impacts and the fact that tastes can differ substantially among people. By utilizing the concepts of the generalized environment and of place utility, a more general and valuable conceptual model can be developed which may be useful in preventing much current conflict over public investment decisions. The model has an explicit concern with the problem of equity and is thus only a small step in a growing field of inquiry within geography.
On Covering Problems and the Central Facilities Location Problem
Authors: White John A. , Case Kenneth E.
Published: September 2010

A number of variations of facilities location problems have appeared in the research literature in the past decade. Among these are problems involving the location of multiple new facilities in a discrete solution space, with the new facilities located relative to a set of existing facilities having known locations. In this paper a number of discrete solution space location problems are treated. Specifically, the covering problem and the central facilities location problem are shown to be related.

The covering problem involves the location of the minimum number of new facilities among a finite number of sites such that all existing facilities (customers) are covered by at least one new facility. The central facilities location problem consists of the location of a given number of new facilities among a finite number of sites such that the sum of the weighted distances between existing facilities and new facilities is minimized. Computational experience in using the same heuristic solution procedure to solve both problems is provided and compared with other existing solution procedures.
Measuring the Shape Distortions of Retail Market Areas
Authors: Simons Peter L.
Published: September 2010

Existing measures of shape rely upon prespecifying boundaries and have little relationship to theory. Where definite shape boundaries do not exist, these problems can be overcome by use of weighted data points and statistical moments. Measures of various shape properties are identified, including compactness and the degree of distortion from the circular shape underlying central place theory and, the gravity model; a bivariate normal distribution is assumed. Examples are included of the application of the measures to suburban retail market areas, although the measures are applicable to all situations in which the statistical model is a reasonable assumption and only subjective boundaries of shape can be identified.
The Optimal Nodal Location of Public Facilities With Price‐Sensitive Demand
Authors: Wagner J. L. , Falkson L. M.
Published: September 2010

The purpose of this paper is to present some models for the location of public facilities in nodal networks that explicitly maximize social welfare by accounting for price‐elastic demand functions. The models presented here are general; yet they are mathematically equivalent to the plant location problem and are therefore amenable to solution procedures developed for the plant location problem. The models presented here distinguish between two institutional environments that reflect the degree of power of the consumer to choose which facility to patronize. If consumers can be assigned arbitrarily to facilities and can be denied service, then the environment is one of public fiat. If consumers must be served at the facility of their choice, then a “serve‐allcomers” environment exists. Separate models for each environment are specified, and the relationship between optimal assignments and pricing policies is developed.
On the Statistical Significance of the Observed Map in Spatial Diffusion
Authors: Yapa Lakshman S.
Published: September 2010

This paper examines the problem of determining the statistical significance of an observed spatial distribution vis‐à‐vis a simulated pattern of the “Hägerstrand type.” It is argued that the sampling distribution for a Hägerstrand type simulator is multinomial. The diffusion model considered is logically equivalent to a multinomial experiment with independent assignment of adoptions to areal cells according to a probability distribution that remains fixed for a given time interval. Conventional tests for goodness of multinomial fit are thus appropriate.
Theoretical and Computational Links between the p‐Median, Location Set‐covering, and the Maximal Covering Location Problem
Authors: Church Richard L. , ReVelle Charles S.
Published: September 2010

It has been shown that the p‐median problem, the location set‐covering and the maximal covering location problems are important facility location models. This paper gives a historical perspective of the development of these models and identifies the theoretical links between them. It is shown that the maximal covering location problem can be structured and solved as a p‐median problem in addition to the several approaches already developed. Computational experience for several maximal covering location problems is given.
Large Sample‐Size Distribution of Statistics Used In Testing for Spatial Correlation
Authors: Sen Ashish
Published: September 2010

Test statistics for testing for spatial correlation in continuous variables have been given by both Moran and Geary and have subsequently been generalized. It has been conjectured for a long time that under the hypothesis of no spatial correlations all these statistics are normally distributed when the sample size is large. This paper proves a very general theorem on the large sample normality of quadratic forms. As corollaries to the theorem the asymptotic normality, under the hypothesis, of all the above‐mentioned statistics is established. The necessary conditions are quite unrestrictive. It is also shown, by means of a counter example, that the conditions given in a similar theorem (Cliff and Ord) are inadequate to ensure normality.
The Construction of the Löschian Landscape
Authors: Marshall John U.
Published: September 2010

Previous descriptions ofLösch's economic landscape have not included accurate rules for maximizing the spatial coincidence of suppliers of different goods. With N denoting the number of farms served by a supplier, the correct procedure is shown to involve separate treatment of (a) cases in which N is of the form x2 or 3x2, (b) cases in which N is a prime number, and (c) all other cases. In the first case the primitive function points of the lattice of suppliers lie on the boundaries of the landscape's conventional subsectors. In the second case the locations for the primitive function points may be chosen at will, but in the third case these locations are completely determined by the locations selected for cases in which N is prime. For all lattices with two or more possible orientations the grid coordinates of the primitive function points correspond to unequiva‐lent solutions of the Diophantine equation used to generate the Löschian numbers. It is also shown that city‐rich and city‐poor sectors do not exist in the Löschian landscape whether or not the spatial coincidence of suppliers is maximized.
Theoretical Underpinnings of the Gravity Hypothesis
Authors: Sheppard Eric S.
Published: September 2010

Various theoretical rationalizations of the gravity hypothesis for spatial interaction are examined. Deterministic utility theory cannot account for variability in individual behavior. Choice models based on Luce's axiom contain some inconsistencies. Random utility theory provides a probabilistic formulation that is internally consistent, and also solves the aggregation problem. However, investigation reveals that, although this provides a theoretical justification for gravity‐like behavior, the assumptions made are sufficiently unrealistic to cast doubt on the empirical validity of the gravity hypothesis.
Information Provision and Individual Behavior: A Case Study of Voting at an English General Election
Authors: Johnston R. J.
Published: September 2010

A basic premise of much work in behavioral geography is that spatial variations in decision making reflect the geography of information availability. Within this context, more attention has been paid to the behavior than to the provision of information. In this paper, both the supply of relevant information and its impact are modeled and analyzed, using the 1983 general election in England as a case study. Variations in campaign spending on information are identified, related to the party's standing in a constituency, and these variations are shown to have been related to the electoral outcome.
Interactions between Weather Stochasticity and the Locations of Pollution Sources and Receptors in Air Quality Planning: A Chance‐Constrained Approach
Authors: Guldmann Jean‐Michel
Published: September 2010

Optimization models for the design of regional air quality control strategies have been developed under the assumption that the annual frequencies of the different meteorological conditions remain constant from year to year. This paper demonstrates empirically that this assumption is not correct, and that the solutions of such models lead either to violation of the annual air quality standard or to unnecessarily high costs for pollution abatement. A chance‐constrained, geographically based approach is formulated to account for the interannual randomness of the meteorological conditions and for the locations of pollution sources and receptors and is applied with different approximation methods. The policy implications of the results in terms of optimal standard selection and implementation of the optimal chance‐constrained pollution abatement plan through decentralized decision‐making by individual pollution sources are assessed.
Shortest‐Path Distances: An Axiomatic Approach
Authors: Smith T. E.
Published: September 2010

An axiomatic approach to distance is developed which focuses on those concepts of distance related to movement in space. The most fundamental types of such distances generally involve some notion of shortest paths between points, where the relevant concept of path length can be any additive attribute of paths (such as physical miles, hours spent in traveling, or gallons of fuel consumed). In particular, the shortest‐path distance between any two points in space is here taken to be the greatest lower bound on all path lengths between these points. This notion of shortest‐path distance is shown to be formally equivalent to a quasimetric, i.e., a distance which satisfies only the classical triangularity axiom for metrics. The main analysis of the paper focuses on the question of whether or not such shortest‐path distances can actually be realized, i.e., on whether there exist shortest paths in space. The central result is to establish a general set of conditions under which such shortest paths always exist. In addition, a condition for the uniqueness of these paths is also established.
Neighbor‐based Properties of Some Orderings of Two‐dimensional Space
Authors: Mark David M.
Published: September 2010

An ordering of a two‐dimensional matrix assigns consecutive integers to the cells in that matrix. This paper evaluates such orderings by concentrating on the differences between each cell's order key and the keys of its spatial neighbors. In all, ten systematically generated orderings and two hundred random trials from a newly defined class of orderings are compared. The row‐by‐row (raster) ordering often used in remote sensing and in matrix ordering within computer programs minimizes the mean absolute difference, the root‐mean‐squared difference (and hence the Geary statistic), and the mean maximum absolute difference for both 8‐by‐8 and 256‐by‐256 matrices; of the quadrant‐recursive (“quadtree‐compatible”) orderings examined, the Morton order had the lowest values for both mean absolute difference measures, whereas the Hilbert order had the lowest root‐mean‐squared neighbor difference. The Morton order has the overall minimum value for the Moran statistic. Heuristic search procedures applied to the 8‐by‐8 case found orderings which had considerably “better” values for these statistics (higher for Moran; lower for the others) than did any of the above, suggesting that it will be possible to define new systematic orderings with better scores than any ordering currently in the literature.
Modeling Suburbanization as an Evolutionary System Dynamic
Authors: Straussfogel Debra
Published: September 2010

The research undertaken investigates the applicability of Allen and Sanglier's dynamic model of urban system evolution to the process of suburbanization occurring in the post‐World War II United States. The model, derived from principles of the theory of dissipative structures formulated by Ilya Prigogine, considers the urban system as open and far from equilibrium, thereby allowing a dynamic evolution which has the following properties. The structure of a system at any point in its development is historically contingent upon the sequence of structures it has exhibited in its past, and on the precise nature of random fluctuations which have acted to induce structural change. The joint action of chance and determinism influence a system's evolution through the complex interactions and feedback mechanisms embedded in its structure. The critical point at which these forces cause the system to undergo a structural change is called a bifurcation point. The model allows that the microdynamics of the system underlie its macrostate. This implies, therefore, the opportunity for individuals to influence the system's structure and for the possibility for creative system evolution to occur.

The central question of the research was whether the processes of deconcentration of population and dispersal of employment from the central cities to the suburbs of large U.S. metropolises, with the resulting morphological shifts from mono‐ to polycentric urban forms, represent structural changes of the sort defined and modeled by Allen and Sanglier's adaptation of Prigogine's theory. The introduction of a calibration procedure, unspecified in previous applications of the model, provides a means whereby the calibration of the many system parameters can proceed in a systematic fashion, offering insight into the function of these parameters in the overall dynamic and their interactions with one another. Research results highlight the benefits of Allen and Sanglier's approach and areas inviting further investigation.
Errors Caused by Rounded Data in Two Simple Facility Location Problems
Authors: Ohsawa Yoshiaki , Koshizuka Takeshi , Kurita Osamu
Published: September 2010

As a rule, data to be used in locational analysis are either rounded up or rounded down. Therefore, error is incurred if such location data are used. The objective of this paper is to examine location error and cost error due to rounding in unweighted minisum and minimax problems in one‐dimensional continuous space. Several conclusions on rounding effects are obtained by examining the respective mean‐squared errors. First, rounding tends to exert more serious influence on the minisum problem than on the minimax problem. Second, in both location problems, the location error shows a pattern that is the inverse of that of the cost error.
Properties of Tests for Spatial Dependence in Linear Regression Models
Authors: Anselin Luc , Rey Serge
Published: September 2010

Based on a large number of Monte Carlo simulation experiments on a regular lattice, we compare the properties of Moran's I and Lagrange multiplier tests for spatial dependence, that is, for both spatial error autocorrelation and for a spatially lagged dependent variable. We consider both bias and power of the tests for six sample sizes, ranging from twenty‐five to 225 observations, for different structures of the spatial weights matrix, for several underlying error distributions, for misspecified weights matrices, and for the situation where boundary effects are present. The results provide an indication of the sample sizes for which the asymptotic properties of the tests can be considered to hold. They also illustrate the power of the Lagrange multiplier tests to distinguish between substantive spatial dependence (spatial lag) and spatial dependence as a nuisance (error autocorrelation).
A Hierarchical Market Model of International Trade
Authors: Hanink Dean M.
Published: September 2010

The characteristics of hierarchical trade flows, when placed in the context of differentiated markets, can provide some insight into the underlying bases of contemporary international trade. A model that relies on differentiated market theory and hierarchical market theory is developed. Trade characteristics derived in the model, concerning the frequency and value of trade, are empirically tested. Empirical results indicate that the model provides a useful framework for the analysis of contemporary international trade.
Housing Price Gradients: The Intersection of Space and Built Form
Authors: Waddell Paul , Berry Brian J. L. , Hoch Irving
Published: September 2010

A hedonic housing price model, implemented for the Dallas region, reveals a housing market structured around multiple nodes, some of which give rise to positive and others to negative externalities. The utility/disutility derived from relative location is capitalized into the size and quality of the housing stock and the nature of neighborhood amenities. The result is a convergence of space and built form.
Employment Dynamics, Spatial Restructuring, and the Business Cycle
Authors: Waddell Paul , Shukla Vibhooti
Published: September 2010

The multinodal metropolis is an evolving system, affected by both long‐term restructuring and by business cycle dynamics. This study of the Dallas‐Fort Worth Metroplex points, first, to the multiplicity and wide dispersion of employment centers within the region and, second, to the importance of vintage. During business cycle upswings new centers in new and more dispersed locations receive the preponderant share of new growth. During business cycle downswings, old activities are pruned most heavily from old locations. The result is an increasingly complex array of specialized agglomerations.
A Statistical Method for Analyzing the Spatial Relationship between the Distribution of Activity Points and the Distribution of Activity Continuously Distributed over a Region
Authors: Okabe Atsuyuki , Sadahiro Yukio
Published: September 2010

This paper shows a statistical method for analyzing the spatial relationship between the distributions of two different kinds of activity in a region. One kind of activity is discretely distributed as points in a region (such as the distribution of retail stores), and the other kind of activity is continuously distributed over the region (such as the distribution of population). First, three models representing the relationship between the above two distributions are formulated. Second, statistical methods for fitting these models to data are developed and the measures of fitness are proposed. Third, using these measures, the relationship between the distributions of thirty‐seven kinds of retail stores and the distribution of population is examined in a suburb of Osaka in Japan.
The Size‐adjusted Critical Region of Moran's I Test Statistics for Spatial Autocorrelation and Its Application to Geographical Areas
Authors: Terui Nobuhiko , Kikuchi Masayoshi
Published: September 2010

In this article, we explore the expression of the asymptotic approximation of the distribution function of Moran's I test statistic for the check of spatial autocorrelation, and we derive a more accurate critical value, which gives the rejection region similar to significant level α to the order of N−1(N = sample size). We show that in some cases our procedure effectively finds the significance of positive spatial autocorrelation in the problem testing for the lack of the spatial autocorrelation. Compared with our method, the testing procedure of Cliff and Ord (1971) is clearly ad hoc and should not be applied blindly, as they pointed out. Our procedure is derived from the theory of asymptotic expansion. We numerically analyze four types of county systems with rectangular lattices and three regional areas with irregular lattices.
Racial Segregation and Class in a Liberal Metropolis
Authors: Morrill Richard
Published: September 2010

As overt racial discrimination lessens and the social and economic status of minorities rises, segregation by class should become more and segregation by race less prominent. This hypothesis is tested via several structural and spatial measures of segregation, for class and for race separately and simultaneously. Even in the ostensibly liberal Seattle, race is found to remain vastly stronger than class for blacks, and even somewhat stronger for Asians.
Local Indicators of Spatial Association—LISA
Authors: Anselin Luc
Published: September 2010

The capabilities for visualization, rapid data retrieval, and manipulation in geographic information systems (GIS) have created the need for new techniques of exploratory data analysis that focus on the “spatial” aspects of the data. The identification of local patterns of spatial association is an important concern in this respect. In this paper, I outline a new general class of local indicators of spatial association (LISA) and show how they allow for the decomposition of global indicators, such as Moran's I, into the contribution of each observation. The LISA statistics serve two purposes. On one hand, they may be interpreted as indicators of local pockets of nonstationarity, or hot spots, similar to the Giand G*istatistics of Getis and Ord (1992). On the other hand, they may be used to assess the influence of individual locations on the magnitude of the global statistic and to identify “outliers,” as in Anselin's Moran scatterplot (1993a). An initial evaluation of the properties of a LISA statistic is carried out for the local Moran, which is applied in a study of the spatial pattern of conflict for African countries and in a number of Monte Carlo simulations.
Special Characteristics of China's Interprovincial Migration
Authors: Li Wen Lang , Li Yuhui
Published: September 2010

This paper examines interprovincial migration in the People's Republic of China (PRC) during 1982–87 when China was going through economic restructuring. Chinese migration patterns bear some resemblances as well as dissimilarities with those generally observed in Western societies. In China, the age‐specific migration rate does not vary much until the preretirement stage. Return to places of origin is obviously the most plausible explanation of Chinese migration patterns. In addition, a clear‐cut gender gap exists, higher than that imagined in Western societies. Chinese women appear far behind Chinese men in their propensity to migrate, and the determinants of migration are quite different for Chinese women and Chinese men.
Solution Techniques for Large Regional Partitioning Problems
Authors: Horn Mark E. T.
Published: September 2010

This paper presents procedures for use in electoral districting and related applications. A region is to be divided into a number of “territories” formed as aggregates of discrete spatial units, subject to constraints on territory size and on intraterritorial connectivity, so as to minimize the total length of territory perimeters. The procedures are based on a hill‐climbing principle, with progressively rigorous application of the connectivity and territory‐size constraints. Computational tests indicate that the best of the procedures provide an effective trade‐off between solution quality and computational efficiency.
New Estimates of Gravitational Attraction by Linear Programming
Authors: O'Kelly Morton E. , Song Wei , Shen Guoqiang
Published: September 2010

This paper uses data for intercity air‐passenger travel to derive a set of general propulsion and attraction factors for twenty‐five large U.S. cities. The paper develops a new way of examining the linkages between flows and nodal attraction. The technique is to assume that the flow data fit a simple gravity model, and then linear programming is used to maximize the consistency of the endogenous propulsion and attraction with the flow data. Various linear models are used to determine the pattern of urban attraction factors that are consistent with the gravitational flows. Linear programming as well as goal programming models are used to develop a set of analyses linking flows to urban hierarchies. Suggestions for further extensions of the method to address substantive issues of urban systems analysis are also provided.