Local Attachment Research Articles

Modelling attachment rates of multi-sized bubbles with particles in a flotation cell

The effect of the bubble size distribution and particle size distribution in a laboratory Denver flotation cell has been investigated using computational fluid dynamics (CFD). Previous work in modelling flotation cells involved mono-sized bubbles and mono-sized particles. The model has been extended to study flotation with a size distribution of bubbles. The flotation effect has been modelled as three sub-processes involving collision, attachment and detachment. The local attachment and detachment rates are calculated from the collision frequency and the probabilities of collision, adhesion and stabilisation. A population-balance approach is adopted in modelling both bubbles and particles in the flotation cell. Results indicate that the bubble distribution has a significant effect on the predicted flotation rate of particles. From comparisons with experimental data, CFD results indicate that the maximum bubble loading under normal cell operation is about 0.2 fractional coverage of the bubble surface.

Histories, belongings, communities

This article uses a range of qualitative sources, stretching from Mass‐Observation to the 1960s research of Brian Jackson and Ray Pahl to examine how far there are shifts in the way people identify with their local communities. The article shows that there is evidence of the rise of aesthetic and ethical orientations to place, whereby individuals provide developed narrative accounts of their choice of residence. I argue that the distinction, much discussed in the 1960s, about the difference between ‘locals’ and ‘incomers’ neglects the fact that they actually both had a functional orientation to locale. The article discusses how the concept of ‘elective belonging’ offers a valuable way of understanding the contemporary politics of local attachment.

Two-Dimensional and Three-Dimensional Simulation of DC Plasma Torches

Two-dimensional modeling of non-transferred dc plasma torches have been performed using an axis symmetric geometrical configuration and boundary conditions. A control volume approach and SIMPLER algorithm is used to solve the governing equations for mass, momentum, and energy conservation coupled with the electric and magnetic fields. The results are compared with the ones obtained in 3-D simulation works of the authors. Results show substantial difference in control parameters as calculated from the two simulations, owing to local attachment of the arc over the anode surface.

Obligation by Association? A Reply to John Horton

In a recent two-part article in this journal, John Horton offers reasons to reject ‘philosophical anarchism’, and claims that rejecting that view should lead us to an ‘associative’ account of political obligations. This article argues for a different conclusion. The claim that local obligations are irreducible or independent is vulnerable to critique, and does not provide a compelling account of moral conflict. Rejecting philosophical anarchism should lead us to a version of moral universalism that can find a place for local attachment.

CFD model of a self-aerating flotation cell

The effect of impeller speed on the air flow in a self-aerated Denver laboratory flotation cell was investigated using computational modelling. Air is induced into the slurry by the impeller's rotating action. The rate of air flow is determined by the suction pressure created by the impeller, the hydrostatic head of the slurry and the frictional losses along the delivery shaft from the inlet valve to the impeller. From two-phase simulations of the flotation cell at varying impeller speeds, the predicted air flow rates have been found to compare favourably against measured values reported in the literature. The effect of increasing impeller speed is to increase the air flow rate and gas holdup in the cell. Simulations with flotation kinetics showed that the gravitational force acting on the attached particles is significant. The effect is a decrease in the bubble rise velocity which in turn affects the flotation rate as predicted by the model. The effects of the local turbulence level on the local attachment rate and bubble loading have been discussed and quantified.

Local clinical attachment scheme in psychiatry

Clinical attachments are an essential step in the process by which international medical graduates (IMGs) secure training posts in the UK. Although the British Medical Association (BMA) provides general guidelines for clinical attachments, the current system lacks a structured process regarding selection, defined length of posts, predetermined contents of training and detailed guidance for consultants supervising clinical attachments in psychiatry. This article outlines the experience in Nottingham of developing a formalised clinical attachment scheme and includes the lessons learnt and difficulties faced during the process. Also presented are the results of feedback surveys from consultants and IMGs who have partaken in the new formalised scheme.

Local-world evolving networks with tunable clustering

We propose an extended local-world evolving network model including a triad formation (TF) step. In the process of network evolution, random fluctuation in the number of new edges is involved. We derive analytical expressions for degree distribution, clustering coefficient and average path length. Our model can unify the generic properties of real-life networks: scale-free degree distribution, high clustering and small inter-node separation. Moreover, in our model, the clustering coefficient is tunable simply by changing the expected number of TF steps after a single local preferential attachment step.

States of Risk: Should Cosmopolitans Favor Their Compatriots?

Recent cosmopolitan thinking attempts to find a place for local (including national) attachment, but all of the proposals offered have been exposed to telling critique. There are objections to the claim that local obligations are only instances of cosmopolitan duty, and to the claim that we can give a moral justification to national societies as networks of mutual benefit. This article argues that it is not mutual benefit but mutual risk that grounds compatriot preference. While exposure to coercion as such does not track national boundaries, exposure to the risks of state abuse, political choice, and social conformity provide us with a reason to take our compatriots' interests seriously. The same argument, however, displays the limits of this reasoning, and also grounds a demanding obligation to aid other societies.

Molecular Mechanisms, Biological Actions, and Neuropharmacology of the Growth-Associated Protein GAP-43

GAP-43 is an intracellular growth-associated protein that appears to assist neuronal pathfinding and branching during development and regeneration, and may contribute to presynaptic membrane changes in the adult, leading to the phenomena of neurotransmitter release, endocytosis and synaptic vesicle recycling, long-term potentiation, spatial memory formation, and learning. GAP-43 becomes bound via palmitoylation and the presence of three basic residues to membranes of the early secretory pathway. It is then sorted onto vesicles at the late secretory pathway for fast axonal transport to the growth cone or presynaptic plasma membrane. The palmitate chains do not serve as permanent membrane anchors for GAP-43, because at steady-state most of the GAP-43 in a cell is membrane-bound but is not palmitoylated. Filopodial extension and branching take place when GAP-43 is phosphorylated at Ser-41 by protein kinase C, and this occurs following neurotrophin binding and the activation of numerous small GTPases. GAP-43 has been proposed to cluster the acidic phospholipid phosphatidylinositol 4,5-bisphosphate in plasma membrane rafts. Following GAP-43 phosphorylation, this phospholipid is released to promote local actin filament-membrane attachment. The phosphorylation also releases GAP-43 from calmodulin. The released GAP-43 may then act as a lateral stabilizer of actin filaments. N-terminal fragments of GAP-43, containing 10-20 amino acids, will activate heterotrimeric G proteins, direct GAP-43 to the membrane and lipid rafts, and cause the formation of filopodia, possibly by causing a change in membrane tension. This review will focus on new information regarding GAP-43, including its binding to membranes and its incorporation into lipid rafts, its mechanism of action, and how it affects and is affected by extracellular agents.

Network properties of written human language

We investigate the nature of written human language within the framework of complex network theory. In particular, we analyze the topology of Orwell's "1984" focusing on the local properties of the network, such as the properties of the nearest neighbors and the clustering coefficient. We find a composite power law behavior for both the average nearest neighbor's degree and average clustering coefficient as a function of the vertex degree. This implies the existence of different functional classes of vertices. Furthermore, we find that the second order vertex correlations are an essential component of the network architecture. To model our empirical results we extend a previously introduced model for language due to Dorogovtsev and Mendes. We propose an accelerated growing network model that contains three growth mechanisms: linear preferential attachment, local preferential attachment, and the random growth of a predetermined small finite subset of initial vertices. We find that with these elementary stochastic rules we are able to produce a network showing syntacticlike structures.

RECIPROCITY AND THE EMERGENCE OF POWER LAWS IN SOCIAL NETWORKS

Research in network science has shown that many naturally occurring and technologically constructed networks are scale free, that means a power law degree distribution emerges from a growth model in which each new node attaches to the existing network with a probability proportional to its number of links (= degree). Little is known about whether the same principles of local attachment and global properties apply to societies as well. Empirical evidence from six ethnographic case studies shows that complex social networks have significantly lower scaling exponents γ ~ 1 than have been assumed in the past. Apparently humans do not only look for the most prominent players to play with. Moreover cooperation in humans is characterized through reciprocity, the tendency to give to those from whom one has received in the past. Both variables — reciprocity and the scaling exponent — are negatively correlated (r = -0.767, sig = 0.075). If we include this effect in simulations of growing networks, degree distributions emerge that are much closer to those empirically observed. While the proportion of nodes with small degrees decreases drastically as we introduce reciprocity, the scaling exponent is more robust and changes only when a relatively large proportion of attachment decisions follow this rule. If social networks are less scale free than previously assumed this has far reaching implications for policy makers, public health programs and marketing alike.

Error and attack tolerance of evolving networks with local preferential attachment

Networks generated by local-world evolving network model display a transition from exponential network to power-law network with respect to connectivity distribution. We investigate statistical properties of the evolving networks and the responses of these networks under random errors and intentional attacks. It has been found that local world size M has great effect on the network's heterogeneity, thus leading to transitional behaviors in network's robustness against errors and attacks. Numerical results show that networks constructed with local preferential attachment mechanism can maintain the robustness of scale-free networks under random errors and concurrently improve reliance against targeted attacks on highly connected nodes.

Multi‐channel shopping: channel use among rural consumers

PurposeThe research purpose was to identify whether changes occurred between 2000 and 2003 in the retail channel use of rural consumers for searching product information and for purchasing food and fiber products and to investigate whether differences existed between channel use groups (i.e. store only shoppers, store and catalog shoppers, and multi‐channel shoppers) concerning perceived time property, satisfaction with local offerings, community attachment, shopping criteria, and financial security.Design/methodology/approachSurvey methodology was used. Questionnaires were mailed to participants living in non‐metropolitan statistical areas of the USA with populations less than 12,500. In 2000, 2,198 participants returned the questionnaire. Follow‐up questionnaires were mailed to the same participants during 2003 and returned by 847 participants. The analysis is based on the responses of the 847 participants.FindingsTo search for information on apparel, food, or home furnishing products, internet use increased slightly as did use of the internet to purchase apparel and home furnishings. Multi‐channel shoppers rated themselves as time‐pressed, dissatisfied with local offerings, unattached to their community, and unconcerned with financial security while shopping.Practical implicationsRural consumers are slowly increasing their use of internet even as they report their satisfaction with shopping with local brick and mortar stores increased during the time period studied. The time is right for rural retailers to enhance both personal and professional relationships with their customers. Rural retailers can capitalize on consumer satisfaction and provide outstanding value and service to keep local customers in local markets.Originality/valueThe paper provides information on new and different retailing practices that satisfy rural consumers in the USA.

Electrical characterization of microdischarges produced by dielectric barrier discharge in dry air at atmospheric pressure

This work addresses the case of millimetre sized plane-to-plane dielectric barrier discharge with sinusoidal voltage between 1 and 60 kHz for different configurations in air at atmospheric pressure. The first aim of this work is to achieve a representative statistical analysis of the electrical characteristics of the microdischarges. The numerical data treatment presented here enables us to determine the maximum current, the duration, the amount of charge and the triggering voltage for each current pulse. Both the average values as well as the deviations are checked. The relative influence of the operating parameters (voltage, gas flow rate, gap width, frequency) on the local surface polarization, electron attachment and temperature affecting microdischarge characteristics has been depicted in different arrangements. A special attention is paid to the influence of dielectric walls inside the discharge gap, perpendicular to the electrodes. Besides, this study allows the identification of the operating conditions for which all the microdischarges can be considered identical to study the local physical and chemical processes around each microdischarge.

Lack of Pain Reduction by a Vibrating Local Anesthetic Attachment: A Pilot Study

A vibrating dental local anesthesia attachment (Vibraject, LLC, Calif) based on the concept of the gate-control theory has been used in clinical practice. The theoretical advantage of the vibrating needle is that it reduces the injection pain. We evaluated the effectiveness of Vibraject in combination with an electrical injection device. Injections were given into the alveolar mucosa adjacent to the root apex of the maxillary lateral incisor in 10 volunteers. Vibraject was randomly applied to either the left or right side of the injection. No statistically significant decrease in pain scores was found at needle insertion or anesthetic injection. The clinical efficacy of Vibraject remains controversial.

Quantifying the Confidence Levels of Deformation Measurements in Asphalt Concrete

Abstract An experimental approach for measuring surface strains in asphalt concrete (AC) samples is presented in this paper. It is equivalent to the local attachment of a large number of linear variable displacement transducers (LVDTs) with gage lengths ranging from 5 to 80 mm. The strain distribution properties developed under conditions of uniaxial tension are studied and analyzed for one AC mixture. It is shown that gage lengths of the order of the nominal maximum aggregate size measure a wide range of strain values: from zero strain up to 5 times the average strain. Moreover, as the gage length is increased, the scatter is reduced and the individual measurements yield values that are closer to their average. Subsequently, the confidence levels associated with using a limited number of gages with a given gage length are quantified. The results are then used to assess test protocol recommendations related to AC sample instrumentation. The size scale of the material's Representative Volume Element (RVE) is also addressed.

Parsing a first language like a second: The erosion of L1 parsing strategies in Spanish-English Bilinguals

Past research suggests that parsing processes in a bilingual's first language (L1) can undergo changes as a function of exposure to a second language (L2). Evidence for this claim comes from studies that have examined how Spanish-English bilinguals resolve temporarily ambiguous sentences containing a complex noun phrase followed by a relative clause, as is the case in “Peter fell in love with the daughter of the psychologist who studied in California.” Previous studies indicate that whereas monolingual Spanish speakers attach the relative clause to the first noun in the complex noun phrase (non-local attachment), monolingual English speakers interpret the relative clause locally (i.e., attach the relative clause to the noun immediately preceding it). With respect to bilinguals, recent research with Spanish-English bilinguals and professional translators (e.g., Dussias 2001, 2003; Parede, 2004) have shown that bilinguals attach the relative clause to the second noun in the complex noun phrase, when reading in Spanish, their first language. The differences observed between monolingual and bilingual speakers have been attributed to experience in a second language immersion environment. For example, Dussias (2003) argues that extensive exposure to a preponderance of English constructions resolved in favor of local attachment can render this interpretation more available, resulting in the low attachment preference observed in Spanish-English bilinguals. Of interest in the present paper is to assess whether speakers with fewer years of immersion experience in the L2 environment than those reported in previous studies employ the correct strategy in each of their languages. To this end, eye-movement data was collected while proficient L1 Spanish/L2 English speakers read ambiguous sentences of the type described above, in their first language, and their performance was compared to a monolingual Spanish group. Analyses revealed that the L1 Spanish speakers of English favored local over non-local attachment when reading in their first languages. The results are most congruent with exposure-based or parallel interactive models of sentence parsing as postulated by Brysbaert & Mitchell (1996), Mitchell & Cuetos (1991) and Mitchell, Cuetos, Corley & Brysbaert (1995), given the assumption within these models that frequency-based exposure affects parsing decisions.

Prevalence of horizontal attachment loss in extracted teeth.

Probing attachment level provides useful information on patterns of destruction of the periodontium. It is difficult to detect complex attachment loss in clinics. The purpose of this study was to estimate prevalence of vertical and horizontal attachment loss in extracted teeth. We collected 10,212 extracted teeth from 130 dentists in Japan. After staining of periodontal membrane with erythrosine, linear loss of vertical and horizontal attachment was measured using a digital caliper. Mean vertical attachment loss varied from 5.3 to 8.6 mm. Incisors had severe attachment loss at mesial sites. Specific local attachment loss at palatal sites was observed in maxillary premolars and molars as well as in mandibular canines and premolars. Horizontal attachment loss was observed in 23% of the teeth. Frequency of horizontal attachment loss of > or = 2.1 mm was 6.4%. Severe attachment loss was observed on the palatal side of maxillary premolars. More than 1/3 of the maxillary first molars showed horizontal attachment loss. It may be impossible to debride 6.4% of teeth in cases of severe periodontitis because horizontal attachment loss may be deeper than the curette blade length.

Disturbed flow promotes deposition of leucocytes from flowing whole blood in a model of a damaged vessel wall.

Departure from simple laminar flow in arteries may promote the local attachment of leucocytes either to intact endothelium or platelet thrombi. We perfused blood through a chamber with a backward facing step, to observe whether adhesion from whole blood to P-selectin was indeed localized to a region of recirculating flow, and whether platelets binding to collagen in such a region could capture leucocytes. Blood flowing over the step established a stable vortex, a reattachment point where forward and backward flow separated, and a simple laminar flow with wall shear rate c. 400/s further downstream. Fluorescently labelled leucocytes were observed to attach to P-selectin immediately upstream or downstream of the reattachment point, and to roll back towards the step or away from it, respectively. There was negligible adhesion further downstream. When a P-selectin-Fc chimaera was used to coat the chamber, stable attachment occurred, again preferentially in the disturbed flow region. Numerous platelets adhered to a collagen coating throughout the chamber, although there were local maxima either side of the reattachment point. The adherent platelets captured flowing leucocytes in these regions alone. Leucocytes may adhere from flowing blood in vessels with high shear rate if the flow is disturbed. While platelets can adhere over a wider range of shear rates, their ability to capture leucocytes may be restricted to regions of disturbed flow.

The Cultural Geography of Gardens

Garden spaces are such a common part of people's everyday experience that they mostly escape scholarly attention. This collection of case studies offers readers a sense of people, places, and gardens based on geographical fieldwork in parts of the world as distinct as Istanbul, Toronto, Sydney, the Peruvian Amazon, and central and northern Mexico. Whether they are called dooryard gardens, home gardens, gardens, backyards, gardens, or market gardens, these spaces of intimate engagement with the land present us with an opportunity to explore important aspects of biodiversity, food sustainability, civil society, the roles of gender and ethnicity in daily life, and how people's lives are affected by migration. Participating authors ask very different research questions and employ a range of qualitative and quantitative methods, encouraging other scholars to pursue stimulating new avenues of research. Clarissa Kimber's introductory article begins with a formidable review of garden studies, complete with three distinct but overlapping categories that show the increasing interest in the cultural and social approach to gardens evident in this collection. William Doolittle's closing article provides an even longer-term perspective, using archaeological evidence to argue that gardens have been around as long as humans have been settled. The variety of perspectives in between show that, although gardeners often bring heritage and traditions to their gardens--and sometimes a bit of nostalgia for a faraway homeland or previous residence--these are dynamic, ever-changing spaces where people actively adapt to the present and nurture hopes for the future. Perhaps because gardens offer migrants or displaced people a sense of settlement and a chance to create a space for themselves and their culture in a new and often hostile place, one of the themes that surfaces throughout this collection is that gardens are landscapes of migration. Gardens also are a key place in which to observe social networks and exchanges, visible in the plant material in the gardens and the rituals that take place there. As community gardens illustrate, gardens offer opportunities for people to learn to coexist peacefully--not a small achievement given the increase of ethnic tensions that accompanies globalization in our shrinking world. Despite the homogenizing influence of globalization on cultural diversity, gardens are places of local attachment to place and even cultural resistance. Many people whose voices you will hear in these articles tell us that gardens matter to them. Some even say they cannot live without them. What this seems to suggest (with clear implications for public policy) is that those to whom gardens matter are often among the less powerful sectors of society--immigrants, squatters, ethnic minorities, the elderly, women, or even refugees. A gardener in Turkey speaks of his last love affair with the bostan he expects to lose to development; an elderly Yugoslav man living in a small unit in Australia uses his neighbor's land to grow spinach; and a woman in Mexico wonders how she will live when her house-lot garden completely disappears as it has to give way to a built-up area. Why are gardens so important to the people who inhabit them? …