348 research outputs found

    Doğu Karadeniz Bölgesi, Artvin yöresi, yapraklı ve iğne yapraklı ormanlarının ölü örtü kütle azalma oranları: ölü örtünün kimyasal yapısının, mikroiklim ve toprak özelliklerinin ayrışma ile olan ilişkisi

    Get PDF
    Plant litter decomposition is controlled by both biotic and abiotic factors. It has been widely hypothesized that litter quality and climatic and soil conditions regulate decomposition. The present study examined the decomposition of native forest tree litter on 2 aspects (the north and the south) and at 3 altitudes (top, middle, and bottom) on each aspect in Artvin province to determine the influence of litter quality, microclimate, and soil characteristics on the rate of decomposition. A litter-bag experiment was performed using beech, oak, fir, and pine litter. The litter bags were placed on the north- and south-facing sites and at 3 altitudes on each aspect and were sampled every 6 months for 2 years. The dominant rate-regulating factor on the litter mass loss rates was found to be the lignin concentration of the litter. The litter from oak and pine contained relatively low lignin levels, and these litter types exhibited significantly faster rates of decay than the highly lignified beech and fir litter. The litter placed on the north-facing site decomposed much faster compared to the south-facing site, and the litter placed at the top altitude on each aspect showed the lowest decay rates compared to either the bottom or middle position throughout the study period. The microclimate and soil characteristics also helped to explain the variation in the litter mass losses, but their effects were less and also showed variations according to the aspects. On the north-facing sites, behind the initial lignin concentration, the litter decomposition was limited by actual evapotranspiration (AET), whereas on the south-facing sites the limiting factor on litter decomposition was soil temperature. However, when the 2 aspects were considered together, lignin concentrations and soil respiration rates were found to be better predictors of the mass loss rates in these forest ecosystems.Ölü örtü ayrışması hem biyotik hem de biyotik olmayan faktörler tarafından kontrol edilmektedir. Ölü örtü ayrışması genel olarak, ölü örtünün kimyasal yapısı ve ortamın iklim ve toprak şartları tarafından kontrol edilmektedir. Buradaki çalışmamızda ise, Artvin yöresinde, farklı bakı ve yükseltide yayılış gösteren doğal ormanlık alanlarda yaygın olarak yetişen bazı ağaç türlerinin yaprak ölü örtülerinin ayrışma oranları çalışılarak, ölü örtü ayrışmasında materyalin kimyasal yapısının, ayrışma ortamının mikroiklim şartlarının ve toprak özelliklerinin etkileri ortaya konulmaya çalışılmıştır. Arazi ortamında ölü örtü ayrışma deneyi için kayın, meşe, göknar ve sarıçam türlerinin yaprak ölü örtüleri kullanılmıştır. Arazide ölü örtü ayrışmasını araştırmak için, özel olarak hazırlanan ölü örtü torbaları (litter bags) içerisine konulan yaprak ölü örtü örneklerinin (yaprak yada ibre), iki farklı bakıya (kuzey ve güney) ve her bir bakının üç farklı yükseltisine (üst, orta, ve alt) yerleştirilmesiyle başlamış ve daha sonra her 6 ayda bir arazi örneklemesi yapılarak 2 yıl süreyle takip edilmiştir. Sonuçlar ölü örtü ayrışmasını etkileyen en baskın faktörün, ayrışan materyalin başlangıçta içerdiği lignin değerinin olduğunu göstermiştir. Yaprak ölü örtüsünde daha az lignin içeren meşe ve sarıçam türleri yapısında daha fazla lignin içeren kayın ve göknar türlerine göre daha hızlı ayrışmıştır. Türlerin yaprak ölü örtüleri bakıya gore karşılaştırıldığında en hızlı ayrışma kuzey bakıda, yükseltiye göre karşılaştırıldığında ise en hızlı ayrışma alt yükseltilerde gerçekleşmiştir. Mikroiklim ve toprak özellikleri, bakıya göre farklılık göstermekle birlikte, ayrışma üzerinde etkili olduğu tespit edilmiştir. Kuzey bakıda, gerçek evapotranspirasyon ayrışmayı sınırlarken, güney bakıda toprak sıcaklığının etkili olduğu bulunmuştur. Her iki bakı da dikkate alındığında ise ölü örtü ayrışması üzerinde ayrışan materyalin içerdiği lignin miktarının ve ayrışmanın gerçekleştiği ortamın toprak solunum oranının ölü örtü ayrışma oranları üzerinde belirliyici faktörler olduğu ortaya konulmuştur

    Monumental Castanea sativa Mill. Individuals on the Slopes of Genya Mountain, Artvin, Turkey

    Get PDF
    Aged trees are considered as a valuable source of information on the past ecological conditions and social life where they are found, and their documentation and preservation are vital for the continuity of benefits they provide. Nineteen Castanea sativa Mill. individuals on abandoned agricultural plots near Artvin city center (Turkey) were measured for diameter at breast height (DBH), circumference at breast height (CBH) and height. DBH and CBH ranged between 72 cm and 186 cm, and between 231 cm and 615 cm, respectively. The highest tree is 22.20 m tall and the shortest is 13.65 m. Estimated ages of the trees ranged from 135 to 342 years. With their size and age, these trees can be designated as monumental trees. Protection of these trees will help in conserving C. sativa genetic resources and in passing the information they hold in their annual rings to future generations

    EXAMINING THE COMMUNICATION AND PROBLEM SOLVING SKILLS OF THE YOUTH CAMP PROGRAM SUPERVISORS

    Get PDF
    Purpose: The purpose of this study is to examine the communication and problem solving skills of the program supervisors who responsible for youth camps run by the Ministry of Youth and Sports in terms of several variables.Material and Method: The study group consisted of 103 participants 45 of whom were female and 58 of whom were male and who were in charge of the youth camps run by the Ministry of Youth and Sports in 2015-2016 period. The “Communication Skills Evaluation Scale (CSES)” was made use of in determining the communication skills of the people who were in charge of youth camps; and the “Problem Solving Inventory (PSI)” was made use of in determining the problem solving skills.The Findings: It was determined upon the analyses that there were no significant differences between the groups in the communication and problem solving skills of the people responsible for running the program in terms of gender, age, marital status, educational status and in-service training variables (p>0.05); however, it was also determined that there were significant differences between the groups in the communication skills according to the time at office variable as the responsible person (p=0.048), and in problem solving skills according to the occupational status variable. (p=0.042). Upon the analyses that were made to determine the origin of these significant differences, it was determined that the communication skills of the people responsible for the programs who worked for 1-2 years and 5 years and over 5 years were higher; and that the problem solving skills of the students were higher than the public employees.Result: According to the findings obtained in the scope of the study, it was determined that there was a decrease in the communication skills in the 3rd and 4th years according to the time at office variable; and it was also determined that the problem solving skills of the students were higher than the employees who were working in public institutions. As a conclusion, it was determined that the communication skills of the supervisors who were responsible for the program were high, and the problem solving skills were at the medium level.   Article visualizations

    Zamana Bağlı Diferansiyel Denklemlerin Laplace Uzayındaki Çözümlerinin Çeşitli Sayısal Yöntemeler İle Karşılaştırılması

    Get PDF
    Konferans Bildirisi -- Teorik ve Uygulamalı Mekanik Türk Milli Komitesi, 2013Conference Paper -- Theoretical and Applied Mechanical Turkish National Committee, 2013Bu çalışmada ilk olarak, basit bir mekanik modele ait diferansiyel denklemin Laplace uzayındaki çözümleri, Fourier uzayındaki çözümleri, Newmark metodu ile zaman uzayında elde edilen çözümleri ve analitik çözümleri ile karşılaştırılacaktır. İkinci olarak, tabakalı kompozit kalın plaklağa ait Navier denklemlerinin Laplace uzayındaki çözümleri ve Newmark metodu ile zaman uzayındaki çözümleri yapılacaktır. Laplace uzayında bulunan çözümler, Durbin’in modifiye edilmiş ters dönüşüm yöntemi kullanılarak zaman uzayına dönüştütrülmektedir. Bu çalışmada, zamana bağlı diferansiyel denklemlere Laplace dönüşümü uygulanması ve ardından Durbin’in modifiye edilmiş ters dönüşüm yöntemi uygulanması ile oldukça etkin ve doğru sonuçlar bulanabildiği literatürdeki çeşitli sayısal yöntemler ile karşılaştırmalar yapılarak gösterilmiştir

    Anti-Simetrik Tabakalanmış Viskoelastik Kalın Plakların Laplace Uzayında Dinamik Analizi

    Get PDF
    Konferans Bildirisi -- Teorik ve Uygulamalı Mekanik Türk Milli Komitesi, 2013Conference Paper -- Theoretical and Applied Mechanical Turkish National Committee, 2013Bu çalışmada ortotropik malzemeye sahip anti-simetrik tabakalanmış viskoelastik kalın plakların dinamik davranışları sonlu elemanlar metodu (SEM) yardımıyla Laplace uzayında teorik olarak incelenmiştir. Anti-simetrik olarak tabakalanmış kalın plakların formülasonunda, birinci mertebe kayma deformasyon teorisi (BKDT) dikkate alınmıştır. Sistemi idare eden hareket denklemi sonlu elemanlar ile zaman uzayında elde edilmiştir. Ardından, hareket denklemine Laplace dönüşümü uygulanarak elde edilen lineer cebrik denklem takımı sayısal olarak çözülmüştür. Plak malzemesinin ortotropik, lineer elastik veya viskoelastik olduğu kabul edilmiştir. Viskoelastik malzeme durumunda Kelvin sönüm modeli kullanılmıştır. Elastisite modülü, elastik-viskoelastik analojisi yardımıyla, Laplace uzayında kompleks karşıtları ile yer değiştirmektedir. Dönüşmüş uzayda elde edilen çözümlerden zaman uzayına geçmek için Durbin’in modifiye edilmiş ters Laplace dönüşüm metodu kullanılmıştır. Bu çalışmada, SEM ile elde edilen hareket denklemlerine Laplace dönüşümü uygulanması ve ardından Durbin’in modifiye edilmiş ters dönüşüm yöntemi uygulanması ile oldukça etkin ve doğru sonuçlar bulunabildiği literatürdeki çeşitli sayısal yöntemler ile karşılaştırılarak gösterilmiştir

    An Examination of Turkish Preschool Curriculum's Effect on Children's Concept Acquisition

    Get PDF
    AbstractThe aim of this study is to examine the effect of Turkish preschool curriculum on children's concept acquisition. The research was carried out assessing children on three occasions, on September 2008, January 2009, and June 2009, respectively. Research was conducted on 24 children who were 5 years old, and schooled according to Turkish preschool curriculum. Bracken Basic Concept Scale-revised (BBCS-R), which has six subtests, was used as data collection instrument. For analyzing the data suitable statistic method was used. The results show that Turkish preschool curriculum has positive effect on children concept acquisition

    Entropically secure encryption with faster key expansion

    Get PDF
    An encryption scheme is called perfect if the cipher reveals no information whatsoever about the message that was encrypted. The quantum Vernam cipher, also known as Quantum One-Time Pad (QOTP) or private quantum channel, is a perfect quantum encryption scheme. In order to perfectly encrypt any nn-qubit state, the necessary and sufficient key length is 2n2n bits. For someone who does not know this key, the state after encryption equals the fully mixed state regardless of the original state. It has been shown that entropic security setting allows us to have information-theoretically secure QOTP with much shorter keys than 2n2n, if the adversary has high uncertainty about the message states. Adversary's uncertainty is quantified using conditional quantum min-entropy. Informally, an encryption scheme is entropically-secure if having the ciphertext does not provide a non-negligible advantage to an attacker in learning any information about the message given that he has high uncertainty about the message. Desrosiers and Dupuis constructed an entropically secure quantum encryption scheme with a key length of n-t+2\log\fr1\qe where nn is the number of the message states, tt is the conditional quantum min entropy of the message state \sH_{\infty}(X|E) and \qe is the leakage of the cipher. They expand the short key to 2n2n using a public string with a length of 2n2n then apply QOTP. Their key expansion method utilizes universal XOR hash function which consists of Galois Field multiplication in GF(22n)(2^{2n}).We have also introduced an entropically secure quantum scheme with a new key expansion method and proved the same shortest key length n-t+2\log\fr1\qe. Our key expansion method is faster than the previous ones. This speedup depends on the entropy of the message and can be multi folds in case of high min-entropy of the message. We encrypt a bipartite state \qf^{AE}\in\cD(\cH_A\otimes\cH_E) using a key k\in\bits^\ell where \ell > n, and \ell is an even integer. In short, we expand a key kk using two random public strings u\in\bits^\ell, v\in\bits^{2n-\ell} by applying GF operations, and then appending the outcome to the key itself: k(uk+v)lsbk \| (uk+v)_{\rm lsb}. GF operations are in GF(22^\ell) and lsb means taking the last 2n2n-\ell bits. Then the expanded key is used in QOTP encryption. The cipherstate consists of nn qubits and 2n2n classical bits

    Estimating the fully burdened cost of supply in a self-sustaining supply chain using an input-output model

    Get PDF
    Armed forces of many countries conduct various operations both at home and worldwide. These operations are conducted not only in areas where procurement is viable, but also in areas where commodities consumed by the logistics activities are not locally available. Estimating and calculating the fully burdened cost of supply in such areas where commodities consumed by the logistics activities are not locally available has become a major research and study field. This study focuses on the effects of change in vehicle fuel consumption rates on fully burdened cost of supplies in a self-sustaining supply chain and how the existence of demand at intermediate nodes affects the fully burdened cost of supplies. After modeling five different scenarios, the effects of changes in the size of convoy and delivery system were analyzed by comparing the results of each scenario. The results of this analysis show that small convoys in supply chains are more efficient than big convoys, and the fuel consumption rate of vehicles is so crucial that it should not be disregarded when estimating fully burdened cost of fuel.http://archive.org/details/estimatingfullyb1094538876Major, Turkish ArmyCaptain, Turkish ArmyApproved for public release; distribution is unlimited
    corecore