Changements saisonniers et altitudinaux des concentrations foliaires en nutriments de Hedera helix L. (Araliaceae)

La résorption est l’une des plus importantes stratégies d’utilisation des nutriments développées par les plantes. Le ratio de la surface foliaire à la masse sèche (SLA) est lié aux nutriments foliaires. Dans la présente étude, les changements de concentration en SLA, N et P, le rapport N/P et la teneur en C des feuilles de lumière et d’ombre de la liane sempervirente Hedera helix L. ont été étudiés au long de l’année sur un gradient altitudinal. L’efficience (RE) et l’efficacité (RP) de la résorption foliaire ont également été calculées dans les feuilles de lumière et celles d’ombre. Les traits foliaires ont montré des changements significatifs entre les localités et au cours de l’année. Des différences significatives sont apparues entre les feuilles de lumière et celles d’ombre pour ce qui concerne le SLA, la concentration en N et la teneur en C, mais se sont avérées dépendantes des différences d’altitude. Toutefois, aucune différence significative de concentration en P n’a été trouvée entre les feuilles de lumière et celles d’ombre. Dans les feuilles, tant de lumière que d’ombre, le SLA augmentait à la fin du printemps et baissait après l’automne. D’une manière générale, la teneur en C augmentait en janvier. La concentration en N des feuilles, tant de lumière que d’ombre, était habituellement la plus faible en début d’été et croissait en octobre. Les plus fortes teneurs en P ont été observées entre décembre et janvier dans toutes les localités. N/P différait significativement selon les localités. L’interaction localité x temps était aussi significative sauf pour les concentrations en P foliaire et N/P. Des corrélations positives ont été notées entre les traits foliaires et ceux du sol comme le SLA, les N, P et C foliaires, l’humidité du sol, et les teneurs en N, P et C. La PRE (efficience de la résorption du phosphore) et la NRP (efficacité de la résorption de l’azote) différaient de manère significative entre les localités mais pas entre les feuilles de lumière ou d’ombre. Cependant, la NRE (efficience de la résorption de l’azote) et la PRP (efficacité de la résorption du phosphore) n’étaient pas significativement différentes. Les feuilles de lumière et celles d’ombre ont montré une resorption incomplète car, dans toutes les localités, les valeurs de NRP et de PRP étaient supérieures aux niveaux de référence.Nutrient resorption is one of the most important nutrient use strategies developed by plants. The ratio of leaf area to dry mass (SLA) is related to leaf nutrients. In this study, the changes in SLA, N, P concentrations, N/P ratio and C content of sun and shade leaves of the evergreen liana Hedera helix L. were investigated over the year in an altitudinal gradient. Foliar resorption efficiency (RE) and proficiency (RP) were also calculated in sun and shade leaves. Leaf traits significantly changed among studied localities and over the year. There were statistically significant differences between sun and shade leaves regarding SLA, N concentration and C content, but these were dependent on the differences of altitude. However, no significant differences were found for P concentrations between sun and shade leaves. SLA increased in sun and shade leaves at the end of the spring and decreased after the fall. Leaf C content generally increased in January. Leaf N concentration in sun and shade leaves was usually lowest in early summer and increased in October. The highest leaf P content was found between December and January in all localities. N/P significantly differed between localities. Locality × time interaction was also significant except leaf P concentrations and N/P. Positive correlations were seen between leaf and soil traits such as SLA, leaf N, P and C, soil moisture, N, P and C. PRE (Phosphorus resorption efficiency) and NRP (Nitrogen resorption proficiency) were significantly different among the localities, but not among sun and shade leaves. However, NRE (Nitrogen resorption efficiency) and PRP (Phosphorus resorption proficiency) were not significantly different. Sun and shade leaves of H. helix showed incomplete resorption, because, in all localities, NRP and PRP values were above the benchmark levels

Influence des facteurs environnementaux sur la distribution et la composition des communautés végétales dans la vallée de la Kizilirmak, région de la mer Noire, Turquie

La présente étude examine le rôle des facteurs environnementaux dans la distribution des associations végétales dans la vallée de la Kizilirmak dans le nord de la Turquie. Elle fournit une analyse quantitative des relations végétation – environnement sur un site de cette vallée. Cent trente parcelles de végétation ont été échantillonnées et analysées à l’aide de TWINSPAN et d’une analyse des correspondances détendancées (DCA) afin d’identifier les principales communautés végétales et de déterminer les gradients environnementaux auxquels elles sont associées. Onze associations et six sous-associations ont été déterminées à l’aide de TWINSPAN dont le dendrogramme individualise trois grands groupes végétaux dans la vallée de la Kizilirmak : les sclérophylles, les xérophylles et les mésophylles. Les principaux axes de la DCA représentent les gradients d’altitude, d’humidité relative et de pH du sol. Des indices de diversité de Shannon et de richesse spécifique ont été calculés pour les associations étudiéesThe aim of this study is to explore the influence of environmental factors on the distribution of plant associations in Kizilirmak Valley, in northern Turkey. This paper provides a quantitative analysis of the vegetation–environment relationships for a study site in this valley. 130 vegetation plots were sampled and analysed using two-way indicator species analysis (TWINSPAN) and Detrended Correspondence Analysis (DCA) in order to identify the principal vegetation communities and determine the environmental gradients associated with these. Eleven associations and six sub- associations were found by using TWINSPAN. There were three main vegetation groups, namely sclerophyllous, xerophyllous and mesophyllous according to TWINSPAN dendrogram, in Kizilirmak valley. The principal DCA axes represent gradients of elevation, relative humidity and soil pH. Shannon diversity index and species richness were also calculated for studied plant association

La résorption foliaire de quelques macro- (N, P, S) et micronutrients (Fe, Zn, Cu, Mn dans les forêts de Pterocarya fraxinifolia (Poiret) Spach en Turquie

Pterocarya fraxinifolia (Poiret) Spach a une distribution plutôt restreinte en Turquie dans les forêts marécageuses. La résorption foliaire de quelques macro- (N, P et S) et micronutriments (Fe, Mn, Zn, Cu) a été étudiée dans des populations de P. fraxinifolia du nord et du sud de la Turquie. Comparativement aux populations méridionales, les populations nordiques ont montré une résorption de l’azote (NRE) plus efficiente mais une résorption du phosphore (PRE) plus faible. Les populations tant nordiques que méridionales se sont montrées P-proficientes alors que seules les populations nordiques se sont révélées P-proficientes. Des valeurs négatives pour ZnRE et MnRE ont été trouvées dans les populations méridionales. SRE s’est révélée plus élevée que celle d’autres espèces décidues. Des ratios NRE/PRE > 1 ont été trouvés dans les populations nordiques mais 1 in northern populations, while <1 in southern populations

ENDOGENOUS FIRM OBJECTIVES

Abstract. We analyze the behavior of a monopolistic firm in general equilibrium when the firm’s decision are taken through shareholder voting. We show that, depending on the underlying distribution, rational voting may imply overproduction as well as underproduction, relative to the efficient level. Any initial distribution of shares is an equilibrium, if individuals do not recognize their influence on voting when trading shares. However, when they do, and there are no short-selling constraints the only equilibrium is the efficient one. With short-selling constraints typically underproduction occurs. It is not market power itself causing underproduction, but the inability to perfectly trade the rights to market power. 1

THE EFFECT OF CREATINE SUPPLEMENTATION ON ATHLETE İSOKİNETİC PERFORMANCE

Bu çalışma; Selçuk Üniversitesi Sağlık Bilimleri Enstitüsünde kabul edilen “Kreatin Yüklemenin Sporcu Performansına Etkisi” isimli doktora tezinin bir bölümüdür.Bu çalışmanın amacı ergojenik yardımcı olarak kullanılan kreatin monohidrat’ın (CrH2O) uzun süreli (6 hafta) yüklemenin sporcu performansına (izokinetik güç ölçümünde toplam iş üretimi) etkisinin belirlenmesidir. Araştırmaya yaşları 20- 27 arasında değişen 38 kişi katılmıştır. Araştırmaya katılan denekler aktif spor yapan sporculardan seçilmiştir. Araştırma bulgularına göre; izokinetik egzersizde kreatin grubunda tüm denekler için tüm setlerde yüklemeden sonra toplam iş üretimi arttı. Birinci ve beşinci setlerde yükleme öncesi ve sonrası değerler arasındaki fark istatistiksel olarak anlamlı bulundu. Kreatin grubunda yükleme öncesi (Yönc)’nden 15. güne göre değişimde bütün setlerde istatistiksel olarak anlamlı bir fark tespit edilmiştir. Aynı şekilde yükleme öncesinden 50. güne göre değişimde ise istatistiksel olarak önemli bir fark tespit edilmemiştir. Plasebo grubu yükleme öncesi ve sonrasında her 5 sette, toplam iş üretim değerleri arasında istatistiksel olarak anlamlı bir fark bulunmadı. Plasebo grubunda yükleme öncesi (Yönc)’nden 15. güne göre değişimde bütün setlerde istatistiksel olarak anlamlı bir fark tespit edilmemiştir. Aynı şekilde yükleme öncesinden 50. güne göre değişimde ise istatistiksel olarak önemli bir fark tespit edilmemiştir. Araştırmanın göze çarpan bulgularında biri, uzun süreli (50 gün) kreatin yüklemenin, maksimal istemli diz ekstansiyonu sırasında kas total iş üretimi değerlerine etkisi olmamıştır fakat yükleme öncesinden 15. güne göre değişimde anlamlı gelişmeler görülmüştür. Bu da total iş üretiminde, uzun süreli yüklemeler yerine iki haftalık yüklemelerin daha olumlu sonuçlar verdiği sonucunu ortaya çıkarmıştırThe purpose of this study is to find the effects of Creatin Monohydrate (CrH2O) on athlete performance (isokinetic power measured as a total workout) used as an ergojenic aid in long-term (6 weeks) supplementation. There are 38 participants willing to join to the study. Their ages are between 20 and 27. All of them are choosed from active athletes. From the findings of this study; all the participants’ in the creatin group have increased the total workout production in all cycles of isokinetic exercise. The difference between the values in the first and fifth cycles, (both before and after loading) are statistically significant. In the creatin group the difference between before loading and 15th day values are statistically significant. But the difference between before loading and 50th day values does not have statistical difference. In placebo group, before and after values in all 5 cycles, there is no statistical difference between the total workout production values. There is also no statistical difference between the before loading and 15th day values. As the same there is no statistical difference between the before loading and the 50th day values. The most important finding in this study is that, there is no affect of long term creatin loading (50 days) on maximal voluntary knee extansion, as a total muscle workout values. But the change in values before loading day and 15th day are significantly improved. And so we understand that, for getting better results in total workout production, we better use two weeks period loading instead of long term loading.

Endogeneous Firm Objectives

We analyze the behavior of a monopolistic firm in general equilibrium when the firm&apos;s decision are taken through shareholder voting