Fibroblasts can condense a hydrated collagen lattice to a tissue-like structure 1/28th the area of the starting gel in 24 hr. The rate of the process can be regulated by varying the protein content of the lattice, the cell number, or the con- centration of an inhibitor such as Colcemid. Fibroblasts of high population doubling level propagated in vitro, which have left the cell cycle, can carry out the contraction at least as efficiently as cycling cells. The potential uses of the system as an immu- nologically tolerated "tissue" for wound hea ing and as a model for studying fibroblast function are discussed.

Production of a tissue-like structure by contraction of collagen lattices by human fibroblasts of different proliferative

Introduction.- Data management and software.- Advice for teachers.- Exploration.- Linear regression.- Generalised linear modelling.- Additive and generalised additive modelling.- Introduction to mixed modelling.- Univariate tree models.- Measures of association.- Ordination--first encounter.- Principal component analysis and redundancy analysis.- Correspondence analysis and canonical correspondence analysis.- Introduction to discriminant analysis.- Principal coordinate analysis and non-metric multidimensional scaling.- Time series analysis--Introduction.- Common trends and sudden changes.- Analysis and modelling lattice data.- Spatially continuous data analysis and modelling.- Univariate methods to analyse abundance of decapod larvae.- Analysing presence and absence data for flatfish distribution in the Tagus estuary, Portugual.- Crop pollination by honeybees in an Argentinean pampas system using additive mixed modelling.- Investigating the effects of rice farming on aquatic birds with mixed modelling.- Classification trees and radar detection of birds for North Sea wind farms.- Fish stock identification through neural network analysis of parasite fauna.- Monitoring for change: using generalised least squares, nonmetric multidimensional scaling, and the Mantel test on western Montana grasslands.- Univariate and multivariate analysis applied on a Dutch sandy beach community.- Multivariate analyses of South-American zoobenthic species--spoilt for choice.- Principal component analysis applied to harbour porpoise fatty acid data.- Multivariate analysis of morphometric turtle data--size and shape.- Redundancy analysis and additive modelling applied on savanna tree data.- Canonical correspondence analysis of lowland pasture vegetation in the humid tropics of Mexico.- Estimating common trends in Portuguese fisheries landings.- Common trends in demersal communities on the Newfoundland-Labrador Shelf.- Sea level change and salt marshes in the Wadden Sea: a time series analysis.- Time series analysis of Hawaiian waterbirds.- Spatial modelling of forest community features in the Volzhsko-Kamsky reserve.

Analysing Ecological Data

This study aimed to review the literature describing and quantifying time lags in the health research translation process. Papers were included in the review if they quantified time lags in the development of health interventions. The study identified 23 papers. Few were comparable as different studies use different measures, of different things, at different time points. We concluded that the current state of knowledge of time lags is of limited use to those responsible for R&D and knowledge transfer who face difficulties in knowing what they should or can do to reduce time lags. This effectively ‘blindfolds’ investment decisions and risks wasting effort. The study concludes that understanding lags first requires agreeing models, definitions and measures, which can be applied in practice. A second task would be to develop a process by which to gather these data.

The Answer Is 17 Years, What Is the Question

In this paper we describe a cellular automaton (CA) simulation model developed to predict urban growth as part of a project for estimating the regional and broader impact of urbanization on the San Francisco Bay area's climate. The rules of the model are more complex than those of a typical CA and involve the use of multiple data sources, including topography, road networks, and existing settlement distributions, and their modification over time. In addition, the control parameters of the model are allowed to self-modify: that is, the CA adapts itself to the circumstances it generates, in particular, during periods of rapid growth or stagnation. In addition, the model was written to allow the accumulation of probabilistic estimates based on Monte Carlo methods. Calibration of the model has been accomplished by the use of historical maps to compare model predictions of urbanization, based solely upon the distribution in year 1900, with observed data for years 1940, 1954, 1962, 1974, and 1990. The complexity of this model has made calibration a particularly demanding step. Lessons learned about the methods, measures, and strategies developed to calibrate the model may be of use in other environmental modeling contexts. With the calibration complete, the model is being used to generate a set of future scenarios for the San Francisco Bay area along with their probabilities based on the Monte Carlo version of the model. Animated dynamic mapping of the simulations will be used to allow visualization of the impact of future urban growth.

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A Self-Modifying Cellular Automaton Model of Historical Urbanization in the San Francisco Bay Area

Poor housing conditions are associated with a wide range of health conditions, including respiratory infections, asthma, lead poisoning, injuries, and mental health. Addressing housing issues offers public health practitioners an opportunity to address an important social determinant of health. Public health has long been involved in housing issues. In the 19th century, health officials targeted poor sanitation, crowding, and inadequate ventilation to reduce infectious diseases as well as fire hazards to decrease injuries. Today, public health departments can employ multiple strategies to improve housing, such as developing and enforcing housing guidelines and codes, implementing “Healthy Homes” programs to improve indoor environmental quality, assessing housing conditions, and advocating for healthy, affordable housing. Now is the time for public health to create healthier homes by confronting substandard housing.

Housing and Health: Time Again for Public Health Action

The Role of Combined Adjunctive 5-Fluorouracil and Low Molecular Weight Heparin in Proliferative Vitreoretinopathy Prevention

Dear Editor: Exposure of scleral explants is not an uncommon postoperative complication [2]. It can lead to acute or acute-onchronic infection that is resistant to antibiotic treatment [3]. The symptoms are chronic discharge and discomfort. Early removal of the explant leads to resolution of the infection and symptoms in most patients. Whilst it is safe to do so in the majority of patients, recurrent re-detachment can occur in between 4 and 47% of patients following explant removal [10]. Particularly at risk are patients with a history of multiple detachment procedures, those with residual vitreoretinal traction, patients with proliferative vitreoretinopathy, those with multiple small post-oral breaks and those in whom the retinal break was not identified at the time of retinal surgery [7]. In these patients, retaining the explant in situ may be the safer option. Simply re-suturing the conjunctiva leads to recurrent breakdown of the wound. We report on the use of sclera and amniotic membrane (AM) to deal with exposed surgical explants. A 68-year-old woman (Case 1) was referred with discomfort in the left eye. Five years ago she had two retinal detachment operations involving pars plana vitrectomies and at her last operation a 276 encircling explant was applied. Her recent symptom was due to a breakdown of the conjunctiva in the inferonasal quadrant (INQ) where the explant was exposed. We applied a donor scleral patch graft to cover and secure the explant. There was a large epithelial defect and the surrounding conjunctiva and Tenon could not be sufficiently mobilised. We used AM and sutured it over the scleral graft using 10/0 Vicryl. At the end of surgery a lid suture was applied and the eye was kept shut for 1 week. At the 12-month follow-up the scleral explant was well covered and the retina was attached. A 36-year-old woman (Case 2) was referred with discomfort in the right eye. Six years ago the patient was treated for a retinal detachment with scleral buckling procedure plus a segmental 276 circumferential explant in the superotemporal quadrant (STQ) as well as a 40-band encirclement. On examination, the 276 scleral explant was exposed in STQ (Fig. 1a) and a Watzke sleeve was found to be prominent over the explant. We performed a scleral graft to cover the explant, replaced the Watzke sleeve with a 5/0 mattress suture and mobilised the conjunctiva and Tenon to cover the scleral graft. A tarsorrhaphy suture was applied for 1 week (Fig. 1b). At the 12-month follow-up the area was well healed (Fig. 1c). Neither of the patients had clinical evidence of infection (significant conjunctival hyperaemia or purulent conjunctival discharge) and both had culture-negative preoperative conjunctival swabs. Postoperatively, both patients were given topical preservative-free chloramphenicol 0.5% and prednisolone 0.5% four times a day for 4 weeks. Neither of the patients were receiving sub-conjunctival antibiotics or steroids at the time of surgery. Biomaterial such as temporalis fascia, fascia lata and preserved pericardium have been used to cover exposed explants [1, 10]. There are also several reports of the use of donor sclera [5, 9]. Irrespective of the material used, recurrent wound dehiscence and breakdown occurred in a Graefe`s Arch Clin Exp Ophthalmol (2007) 245:915–916 DOI 10.1007/s00417-006-0502-4

Treatment of exposed explants with donor sclera and amniotic membrane.

Visual outcome in 26 blind retinitis pigmentosa patients after implantation of subretinal Alpha-IMS devices

Congressional redistricting is the process of delineating boundaries for districts in which voters elect members to the United States (U.S.) House of Representatives. Currently, state legislative bodies and committees may consider up to eight criteria when determining the boundaries of districts and this paper focuses on one of those criteria, equal population. Congressional districts (CDs) are drawn to provide quality representation for a large population and are often redrawn due to changes in population reflected by the decennial census. The U.S. Supreme Court recently decided that equal population refers to the total population of a state, rather than any subgroups (e.g. registered voters, voting eligible population) but did not dictate that states could not evenly distribute any subgroups as well. This paper discusses how eligible voters may be defined and their distributions in each state for the 113th Congress. States with a large proportion of children or prisoners were expected to have CDs with eligible voting populations deviated from the equal population counts, but the results show that populations of children and prisoners were not significant factors related to the deviations from equal population counts at the state level. However, the changes in population between 2000 and 2010, and the non-citizen and Hispanic populations were strongly and significantly associated with the deviations from the ideals.

David Wong

Papers

The Role of Combined Adjunctive 5-Fluorouracil and Low Molecular Weight Heparin in Proliferative Vitreoretinopathy Prevention

Treatment of exposed explants with donor sclera and amniotic membrane.

Visual outcome in 26 blind retinitis pigmentosa patients after implantation of subretinal Alpha-IMS devices

Congressional districts: How “equal” are they?

Genetic Deletion or Pharmacological Inhibition of Aldose Reductase Protects the Retina in a Mouse Model of Ischemia-induced Retinopathy