Anemia and chronic kidney disease are potential risk factors for mortality in stroke patients : a historic cohort study

Rapport de synthèseApproche et objectifL'objectif de la recherche était de préciser les relations existant entre l'insuffisance rénale chronique, l'anémie et l'accident vasculaire cérébral parmi des patients hospitalisés au Centre Hospitalier Universitaire Vaudois (CHUV) pour un accident vasculaire cérébral (AVC). Les auteurs ont déterminé la prévalence de l'anémie et de l'insuffisance rénale chronique parmi ces patients et examiné s'ils sont des facteurs de risque indépendants de la mortalité suite à un AVC.L'insuffisance rénale chronique est associée à un risque élevé de développer un AVC. L'anémie est une complication et une conséquence fréquente qui découle de l'insuffisance rénale chronique et est également un facteur de risque pour les maladies cérébro- et cardiovasculaires.MéthodeLa présente étude de cohorte rétrospective se base sur le registre des AVC du CHUV et inclut tous les patients traités suite à un premier AVC au service de neurologie du CHUV entre les années 2000 et 2003.Les variables utilisées pour l'analyse sont les caractéristiques démographiques, l'insuffisance rénale chronique, le débit de filtration glomérulaire.(GFR), l'anémie et d'autres facteurs de risque d'AVC. Ils ont été récoltés au moyen du système informatique du laboratoire du CHUV, d'entretiens téléphoniques (patients ou proches) et du registre des AVC du CHUV.L'insuffisance rénale chronique a été calculée sur base de la ,,Kidney Disease Outcomes Quality Initiative (K/DOQI)-CKD Classification", laquelle est divisée en cinq stades. L'anémie a été définie par une hémoglobine de < 120g/L pour les femmes et < 130g/L pour les hommes.Les analyses statistiques réalisées sont des tests Chi-carré, des tests de Τ ainsi que des courbes de Kaplan-Meier et le modèle de régression de Cox.RésultatsParmi 890 patients adultes avec un AVC, le GFR moyen était de 64.3 ml/min/1.73 m2, 17% souffraient d'anémie et 10% sont décédés pendant la première année après la sortie de l'hôpital, suite à l'"AVC index". Parmi ceux-ci, 61% avaient une insuffisance rénale chronique de stade 3-5 et 39% de stade 1 ou 2 selon les critères de K/DOQI.D'autre part un taux d'hémoglobine élevé a pu être associé à un risque moins élevé de mortalité un an après la sortie de l'hôpital.Conclusion et perspectiveNous avons constaté que l'anémie ainsi que l'insuffisance rénale chronique sont fréquents parmi les patients souffrant d'un AVC et qu'ils sont des facteurs de risque d'un taux de mortalité élevé après un an. En conséquence, il pourrait être utile de traiter les patients souffrant d'anémie et d'insuffisance rénale dès que possible afin de diminuer les complications et comorbidités résultants de ces maladies.La perspective est de rendre les cliniciens attentif à l'importance de l'insuffisance rénale et de l'anémie parmi les patients ayants développé un AVC, ainsi que d'initier le traitement approprié afin de diminuer les complications, les comorbidités ainsi que les récidives d'un AVC. L'efficacité et l'économicité des interventions visant à améliorer le pronostic chez les patients présentant un AVC et souffrant d'une insuffisance rénale chronique et / ou d'une anémie doivent être évaluées par des études appropriées.

Changing landscapes of Switzerland: assessing effects of historic and future land uses and land covers on the occurrence of selected butterfly species

Summary Landscapes are continuously changing. Natural forces of change such as heavy rainfall and fires can exert lasting influences on their physical form. However, changes related to human activities have often shaped landscapes more distinctly. In Western Europe, especially modern agricultural practices and the expanse of overbuilt land have left their marks in the landscapes since the middle of the 20th century. In the recent years men realised that mare and more changes that were formerly attributed to natural forces might indirectly be the result of their own action. Perhaps the most striking landscape change indirectly driven by human activity we can witness in these days is the large withdrawal of Alpine glaciers. Together with the landscapes also habitats of animal and plant species have undergone vast and sometimes rapid changes that have been hold responsible for the ongoing loss of biodiversity. Thereby, still little knowledge is available about probable effects of the rate of landscape change on species persistence and disappearance. Therefore, the development and speed of land use/land cover in the Swiss communes between the 1950s and 1990s were reconstructed using 10 parameters from agriculture and housing censuses, and were further correlated with changes in butterfly species occurrences. Cluster analyses were used to detect spatial patterns of change on broad spatial scales. Thereby, clusters of communes showing similar changes or transformation rates were identified for single decades and put into a temporally dynamic sequence. The obtained picture on the changes showed a prevalent replacement of non-intensive agriculture by intensive practices, a strong spreading of urban communes around city centres, and transitions towards larger farm sizes in the mountainous areas. Increasing transformation rates toward more intensive agricultural managements were especially found until the 1970s, whereas afterwards the trends were commonly negative. However, transformation rates representing the development of residential buildings showed positive courses at any time. The analyses concerning the butterfly species showed that grassland species reacted sensitively to the density of livestock in the communes. This might indicate the augmented use of dry grasslands as cattle pastures that show altered plant species compositions. Furthermore, these species also decreased in communes where farms with an agricultural area >5ha have disappeared. The species of the wetland habitats were favoured in communes with smaller fractions of agricultural areas and lower densities of large farms (>10ha) but did not show any correlation to transformation rates. It was concluded from these analyses that transformation rates might influence species disappearance to a certain extent but that states of the environmental predictors might generally outweigh the importance of the corresponding rates. Information on the current distribution of species is evident for nature conservation. Planning authorities that define priority areas for species protection or examine and authorise construction projects need to know about the spatial distribution of species. Hence, models that simulate the potential spatial distribution of species have become important decision tools. The underlying statistical analyses such as the widely used generalised linear models (GLM) often rely on binary species presence-absence data. However, often only species presence data have been colleted, especially for vagrant, rare or cryptic species such as butterflies or reptiles. Modellers have thus introduced randomly selected absence data to design distribution models. Yet, selecting false absence data might bias the model results. Therefore, we investigated several strategies to select more reliable absence data to model the distribution of butterfly species based on historical distribution data. The results showed that better models were obtained when historical data from longer time periods were considered. Furthermore, model performance was additionally increased when long-term data of species that show similar habitat requirements as the modelled species were used. This successful methodological approach was further applied to assess consequences of future landscape changes on the occurrence of butterfly species inhabiting dry grasslands or wetlands. These habitat types have been subjected to strong deterioration in the recent decades, what makes their protection a future mission. Four spatially explicit scenarios that described (i) ongoing land use changes as observed between 1985 and 1997, (ii) liberalised agricultural markets, and (iii) slightly and (iv) strongly lowered agricultural production provided probable directions of landscape change. Current species-environment relationships were derived from a statistical model and used to predict future occurrence probabilities in six major biogeographical regions in Switzerland, comprising the Jura Mountains, the Plateau, the Northern and Southern Alps, as well as the Western and Eastern Central Alps. The main results were that dry grasslands species profited from lowered agricultural production, whereas overgrowth of open areas in the liberalisation scenario might impair species occurrence. The wetland species mostly responded with decreases in their occurrence probabilities in the scenarios, due to a loss of their preferred habitat. Further analyses about factors currently influencing species occurrences confirmed anthropogenic causes such as urbanisation, abandonment of open land, and agricultural intensification. Hence, landscape planning should pay more attention to these forces in areas currently inhabited by these butterfly species to enable sustainable species persistence. In this thesis historical data were intensively used to reconstruct past developments and to make them useful for current investigations. Yet, the availability of historical data and the analyses on broader spatial scales has often limited the explanatory power of the conducted analyses. Meaningful descriptors of former habitat characteristics and abundant species distribution data are generally sparse, especially for fine scale analyses. However, this situation can be ameliorated by broadening the extent of the study site and the used grain size, as was done in this thesis by considering the whole of Switzerland with its communes. Nevertheless, current monitoring projects and data recording techniques are promising data sources that might allow more detailed analyses about effects of long-term species reactions on landscape changes in the near future. This work, however, also showed the value of historical species distribution data as for example their potential to locate still unknown species occurrences. The results might therefore contribute to further research activities that investigate current and future species distributions considering the immense richness of historical distribution data. Résumé Les paysages changent continuellement. Des farces naturelles comme des pluies violentes ou des feux peuvent avoir une influence durable sur la forme du paysage. Cependant, les changements attribués aux activités humaines ont souvent modelé les paysages plus profondément. Depuis les années 1950 surtout, les pratiques agricoles modernes ou l'expansion des surfaces d'habitat et d'infrastructure ont caractérisé le développement du paysage en Europe de l'Ouest. Ces dernières années, l'homme a commencé à réaliser que beaucoup de changements «naturels » pourraient indirectement résulter de ses propres activités. Le changement de paysage le plus apparent dont nous sommes témoins de nos jours est probablement l'immense retraite des glaciers alpins. Avec les paysages, les habitats des animaux et des plantes ont aussi été exposés à des changements vastes et quelquefois rapides, tenus pour coresponsable de la continuelle diminution de la biodiversité. Cependant, nous savons peu des effets probables de la rapidité des changements du paysage sur la persistance et la disparition des espèces. Le développement et la rapidité du changement de l'utilisation et de la couverture du sol dans les communes suisses entre les années 50 et 90 ont donc été reconstruits au moyen de 10 variables issues des recensements agricoles et résidentiels et ont été corrélés avec des changements de présence des papillons diurnes. Des analyses de groupes (Cluster analyses) ont été utilisées pour détecter des arrangements spatiaux de changements à l'échelle de la Suisse. Des communes avec des changements ou rapidités comparables ont été délimitées pour des décennies séparées et ont été placées en séquence temporelle, en rendrent une certaine dynamique du changement. Les résultats ont montré un remplacement répandu d'une agriculture extensive des pratiques intensives, une forte expansion des faubourgs urbains autour des grandes cités et des transitions vers de plus grandes surfaces d'exploitation dans les Alpes. Dans le cas des exploitations agricoles, des taux de changement croissants ont été observés jusqu'aux années 70, alors que la tendance a généralement été inversée dans les années suivantes. Par contre, la vitesse de construction des nouvelles maisons a montré des courbes positives pendant les 50 années. Les analyses sur la réaction des papillons diurnes ont montré que les espèces des prairies sèches supportaient une grande densité de bétail. Il est possible que dans ces communes beaucoup des prairies sèches aient été fertilisées et utilisées comme pâturages, qui ont une autre composition floristique. De plus, les espèces ont diminué dans les communes caractérisées par une rapide perte des fermes avec une surface cultivable supérieure à 5 ha. Les espèces des marais ont été favorisées dans des communes avec peu de surface cultivable et peu de grandes fermes, mais n'ont pas réagi aux taux de changement. Il en a donc été conclu que la rapidité des changements pourrait expliquer les disparitions d'espèces dans certains cas, mais que les variables prédictives qui expriment des états pourraient être des descripteurs plus importants. Des informations sur la distribution récente des espèces sont importantes par rapport aux mesures pour la conservation de la nature. Pour des autorités occupées à définir des zones de protection prioritaires ou à autoriser des projets de construction, ces informations sont indispensables. Les modèles de distribution spatiale d'espèces sont donc devenus des moyens de décision importants. Les méthodes statistiques courantes comme les modèles linéaires généralisés (GLM) demandent des données de présence et d'absence des espèces. Cependant, souvent seules les données de présence sont disponibles, surtout pour les animaux migrants, rares ou cryptiques comme des papillons ou des reptiles. C'est pourquoi certains modélisateurs ont choisi des absences au hasard, avec le risque d'influencer le résultat en choisissant des fausses absences. Nous avons établi plusieurs stratégies, basées sur des données de distribution historique des papillons diurnes, pour sélectionner des absences plus fiables. Les résultats ont démontré que de meilleurs modèles pouvaient être obtenus lorsque les données proviennent des périodes de temps plus longues. En plus, la performance des modèles a pu être augmentée en considérant des données de distribution à long terme d'espèces qui occupent des habitats similaires à ceux de l'espèce cible. Vu le succès de cette stratégie, elle a été utilisée pour évaluer les effets potentiels des changements de paysage futurs sur la distribution des papillons des prairies sèches et marais, deux habitats qui ont souffert de graves détériorations. Quatre scénarios spatialement explicites, décrivant (i) l'extrapolation des changements de l'utilisation de sol tels qu'observés entre 1985 et 1997, (ii) la libéralisation des marchés agricoles, et une production agricole (iii) légèrement amoindrie et (iv) fortement diminuée, ont été utilisés pour générer des directions de changement probables. Les relations actuelles entre la distribution des espèces et l'environnement ont été déterminées par le biais des modèles statistiques et ont été utilisées pour calculer des probabilités de présence selon les scénarios dans six régions biogéographiques majeures de la Suisse, comportant le Jura, le Plateau, les Alpes du Nord, du Sud, centrales orientales et centrales occidentales. Les résultats principaux ont montré que les espèces des prairies sèches pourraient profiter d'une diminution de la production agricole, mais qu'elles pourraient aussi disparaître à cause de l'embroussaillement des terres ouvertes dû à la libéralisation des marchés agricoles. La probabilité de présence des espèces de marais a décrû à cause d'une perte générale des habitats favorables. De plus, les analyses ont confirmé que des causes humaines comme l'urbanisation, l'abandon des terres ouvertes et l'intensification de l'agriculture affectent actuellement ces espèces. Ainsi ces forces devraient être mieux prises en compte lors de planifications paysagères, pour que ces papillons diurnes puissent survivre dans leurs habitats actuels. Dans ce travail de thèse, des données historiques ont été intensivement utilisées pour reconstruire des développements anciens et pour les rendre utiles à des recherches contemporaines. Cependant, la disponibilité des données historiques et les analyses à grande échelle ont souvent limité le pouvoir explicatif des analyses. Des descripteurs pertinents pour caractériser les habitats anciens et des données suffisantes sur la distribution des espèces sont généralement rares, spécialement pour des analyses à des échelles fores. Cette situation peut être améliorée en augmentant l'étendue du site d'étude et la résolution, comme il a été fait dans cette thèse en considérant toute la Suisse avec ses communes. Cependant, les récents projets de surveillance et les techniques de collecte de données sont des sources prometteuses, qui pourraient permettre des analyses plus détaillés sur les réactions à long terme des espèces aux changements de paysage dans le futur. Ce travail a aussi montré la valeur des anciennes données de distribution, par exemple leur potentiel pour aider à localiser des' présences d'espèces encore inconnues. Les résultats peuvent contribuer à des activités de recherche à venir, qui étudieraient les distributions récentes ou futures d'espèces en considérant l'immense richesse des données de distribution historiques.

Iowa’s Historic Automobile Roads A National Register Study of Pre-1948 Arterial Highways, 2009

This study of Iowa’s Historic Automobile Roads has been prepared by the Highway Archaeology Program under the terms of an annual cultural resource surveys contract between the Iowa DOT and The University of Iowa. Under this agreement, state transportation funds are appropriated by the Iowa DOT for The University of Iowa Highway Archaeology Program to locate and determine the significance of cultural resources in the area of proposed highway and transportation improvement work. Cultural resources include archaeological, historical, and architectural sites. The study of Iowa’s Historic Automobile Roads reported herein, including archival research and survey, was conducted between June 2002 and June 2007, by Marlin R. Ingalls and Maria F. Schroeder. The University of Iowa Highway Archaeology Program is solely responsible for the content and accuracy of these reports with respect to site location description, interpretation, and recommendations. Duplicate project reports are filed at the State Historic Preservation Office (SHPO), Community Programs Bureau in Des Moines. Illustrations in this report may have been altered for clarity and sized to fit the page.

Some historic markers in Iowa,1943.

This book is part of the Iowa Monograph Series, number 8, edited by Ruth A. Gallager. It was compiled by Susie Webb Wright and includes information on markers and monuments in Iowa which tell of people, places, incidents, or events connected with Iowa history.

National register of historic places in Iowa,1978.

This is a list of properties in Iowa in 1978 that are on the National Register of Historic Places. These properties are recognized as being historically, architecturally and archaeologically significant through a program of registration, financial aid and incentive, and partial protection from damage or destruction by federally-funded projects.

Iowa Historic Property Study of the Zeman Barn, 2009

The Zeman Barn (86-00028) is an early twentieth-century example of a gothic roofed barn and is part of the Zeman Farmstead located along U.S. Highway 30 in Otter Creek Township (Township 38N, Range 14W), Tama County, Iowa (Figures 1 and 2). The farmstead was initially evaluated in a reconnaissance architectural survey conducted in 1998 by The Louis Berger Group, Inc (Berger). An intensive architectural survey of the property by Berger’s Principal Architectural Historian, Martha H. Bowers, evaluated the farmstead as not being eligible for listing in the National Register of Historic Places (National Register) but noted that the barn appears to be eligible for listing in the National Register under Criterion C (Bowers 1998). At the request of the Iowa Department of Transportation, Berger completed the recordation project to provide a documentary record of the Zeman Barn in accordance with the guidelines set forth by the Iowa State Historic Preservation Office regarding historic property studies for barns. Background research for this project was conducted in September 2008 and April 2009. The property was inspected and photographed in May 2008. Information on the property was gathered through background research, interviews with Zeman family members, field investigation, and photo documentation. Historical maps of the project area were used to collect data necessary for developing regional and local historic contexts. The research for this report was conducted at the Tama County Courthouse and the Tama County Historical Museum Genealogical Library, both in Toledo. Much of the background research for the project was conducted by Camilla Deiber and Michael Dulle. Ms. Deiber also prepared the photographic documentation, plan drawings, and the graphics used in this report. Mr. Roger L. Ciuffo conducted interviews with Zeman family members and wrote this report.

Anemia and chronic kidney disease are potential risk factors for mortality in stroke patients: a historic cohort study.

BACKGROUND: Chronic kidney disease (CKD) is associated to a higher stroke risk. Anemia is a common consequence of CKD, and is also a possible risk factor for cerebrovascular diseases. The purpose of this study was to examine if anemia and CKD are independent risk factors for mortality after stroke. METHODS: This historic cohort study was based on a stroke registry and included patients treated for a first clinical stroke in the stroke unit of one academic hospital over a three-year period. Mortality predictors comprised demographic characteristics, CKD, glomerular filtration rate (GFR), anemia and other stroke risk factors. GFR was estimated by means of the simplified Modification of Diet in Renal Disease formula. Renal function was assessed according to the Kidney Disease Outcomes Quality Initiative (K/DOQI)-CKD classification in five groups. A value of hemoglobin < 120 g/L in women and < 130 g/L in men on admission defined anemia. Kaplan-Meier survival curves and Cox models were used to describe and analyze one-year survival. RESULTS: Among 890 adult stroke patients, the mean (Standard Deviation) calculated GFR was 64.3 (17.8) ml/min/1.73 m2 and 17% had anemia. Eighty-two (10%) patients died during the first year after discharge. Among those, 50 (61%) had K/DOQI CKD stages 3 to 5 and 32 (39%) stages 1 or 2 (p < 0.001). Anemia was associated with an increased risk of death one year after discharge (p < 0.001). After adjustment for other factors, a higher hemoglobin level was independently associated with decreased mortality one year after discharge [hazard ratio (95% CI) 0.98 (0.97-1.00)]. CONCLUSIONS: Both CKD and anemia are frequent among stroke patients and are potential risk factors for decreased one-year survival. The inclusion of patients with a first-ever clinical stroke only and the determination of anemia based on one single measure, on admission, constitute limitations to the external validity. We should investigate if an early detection and management of both CKD and anemia could improve survival in stroke patients.

Indian Creek Channel: the evolution & significance of an historic public works administration flood control facility, Council Bluffs, Iowa, 2010

Plagued for nearly a century by the perennial flooding of Indian Creek, the City begins construction on a massive channelization project designed to confine the creek to its banks. Funded largely through a grant from the recently established Public Works Administration (PWA), the Indian Creek Channel, upon its completion two years later, would become the largest PWA undertaking in the State of Iowa. Though it did not completely end flooding in Council Bluffs, construction of the Indian Creek Channel did substantially reduce both the number and severity of the city's subsequent floods. It also profoundly impacted the residential and commercial development of Council Bluffs, as well as the city's sanitary conditions. The effects of the Indian Creek channelization, both practical and historical, are still realized today. In 2009, plans for a City road and bridge construction project at the intersection of North Broadway Street and Kanesville Boulevard proposed to replace a 221-foot-long segment of the Indian Creek Channel with a concrete box culvert. In compliance with the National Historic Preservation Act, a cultural resources study was conducted at the proposed construction site, the findings of which concluded that the historic character of the Indian Creek Channel would be compromised by the impending construction. As a means of mitigating these damages, an agreement was reached among the City, the Iowa State Historic Preservation Office, and the Federal Highway Administration that resulted in detailed research and documentation of the historical significance of the Indian Creek Channel. The findings of that study are summarized in this publication.

Report on the Historic Preservation and Cultural and Entertainment District Tax Credit program administered by the State Historic Preservation Office within the State Historical Society of Iowa, a division of the Department of Cultural Affairs, for the period July 1, 2000 through June 30, 2013

Report on the Historic Preservation and Cultural and Entertainment District Tax Credit program administered by the State Historic Preservation Office within the State Historical Society of Iowa, a division of the Department of Cultural Affairs, for the period July 1, 2000 through June 30, 2013

Iowa Historic Property Study: Iowa-Illinois Memorial Bridge Carrying I-74 and U.S. 6 over Mississippi River between Bettendorf, Scott County, Iowa and Moline, Rock Island County, Illinois, 2012

The 1935 Iowa-Illinois Memorial Bridge is being documented at this time to fulfill the requirements of the Memorandum of Agreement regarding the removal of the Iowa-Illinois Memorial Bridge and the Iowana Farms Milk Company Building for the proposed improvements to Interstate 7 4 in Bettendorf, Iowa, and Moline, Illinois.1 The 1959 twin suspension bridge will be removed as well, but it was determined to be ineligible for the National Register of Historic Places. Discussion of the history of the 1959 twin span is included, however, in the current report as part of the overall history of the Iowa-Illinois Memorial Bridge. Fieldwork for the documentation occurred in November 2009 and October 2010 (Fig. 1). Limitations on photography included limited shoreline access on the Illinois side, making good views of the bridge from the south somewhat challenging. Also, photographs on the bridge deck were not possible because of interstate traffic and prohibitions on pedestrian traffic. Within the last few years, online primary sources have proliferated, along with historical materials regarding the Iowa-Illinois Memorial Bridge. Sources available online for this report included numerous historical photographs, as well as historical Davenport, Iowa, and U.S. newspapers that document the bridge planning and construction. Additional primary source material was found at the University of Iowa Libraries, the State Historical Society of Iowa in Iowa City, the Bettendorf Public Library, the Richardson-Sloane Special Collections Center at the Davenport Public Library, and the Iowa State University Special Collections in Ames.

Iowa Historic Property Study: Iowana Farms Milk Company, 1416 State Street, City of Bettendorf, Scott County, Iowa, 2012

The Iowana Farms Milk Company factory building was considered to retain sufficient integrity and possess sufficient significance to be considered eligible for the National Register of Historic Places under Criteria A and C for its historical and architectural significance in the Bettendorf community. The Iowana Farms Milk Company was an important early to mid-twentieth-century business in Bettendorf, and was among the few that was not owned or operated by the Bettendorf Company. It was a strong and thriving business for many years, and its products were well known in the Quad Cities region. The importance of this property becomes even more significant when one considers that most of the buildings once associated with the actual Bettendorf Company, which was undeniably the most important business and industry in town, are now gone. As a result, the Iowana Farms Milk Company factory building was a physical vestige of the once-thriving commercial industries that made Bettendorf into a city in the twentieth century. This property was further significant for its representation of the evolution of the dairy industry in the twentieth century from farm to factory production. It also reflected the changes to the industry based on scientific discoveries, mechanical innovations, and governmental regulations related to improved sanitation and the pure milk movement. The Iowana Farms Milk Company represented a model plant for the time, and the marketing strategies it employed followed the trends of the industry. The Iowana Farms Milk Company plant had to be removed to make room for a new I-74 bridge over the Mississippi River at Bettendorf. The construction of the new bridge also required removal of the historic Iowa-Illinois Memorial Bridge. The documentation reported herein and for that of the Iowa-Illinois Memorial Bridge fulfills the requirements of the Memorandum of Agreement regarding the removal of these historic properties.

Influence of "historic" photoperiod during stem elongation on the number of fertile florets in wheat

Extending the duration of the late reproductive phase in wheat has been proposed as a possible avenue to improve spike fertility. There is a positive correlation between the number of fertile florets and the duration of the stem elongation phase when this phase is varied by extended photoperiod. Photoperiod treatments imposed during the vegetative period also influence the duration of stem elongation. The present study analysed the effect of long photoperiod (19 h) of different duration (10, 12, 14, 18 or 22 d) imposed before the onset of stem elongation on floret fertility in wheat. It was found that the length of the stem elongation phase was modified by earlier ‘historic ’ photoperiod treatments imposed during previous phases. However, neither the number of fertile florets per spike nor the spikelet fertility was affected significantly by these historic treatments. The results of the study therefore showed that an increased duration of the late reproductive phase was ineffective in increasing the number of fertile florets, unless the length of that phase was directly altered by current photoperiod.