Öz: Selçuklular Dandanakan Savaşı’ndan sonra batıya doğru ilerleyişlerini hızlandırarak on yıldan az bir sürede Anadolu kapılarına ve Bilâd-ı Şâm’a kadar ulaşmışlardır. Söz konusu fetih hareketleri ...esnasında hâkim oldukları şehirlerin yönetimini belirli yükümlülükleri yerine getirmeleri şartıyla eski yöneticilere bırakmışlardır. Bu şekilde hâkimiyet alanları içinde otoritelerini güçlendirmiş hem de mevcut yöneticilerin tecrübe ve kabiliyetlerinden istifade etmişlerdir. Basra Körfezi kıyısında İran ve Irak toprakları içinde bulunan Hûzistân, Vâsıt, Basra, Şîrâz ve Errâcân gibi şehirlerin idaresi de Hezâresb b. Bengîr adında mahalli bir idarecinin hâkimiyeti altında bulunuyordu. Tuğrul Bey, 447 (1055) yılında Bağdat’a geldikten sonra mezkûr şehirlerin idaresini eskiden olduğu gibi Hezâresb’e bırakmıştır. Selçukluların hâkim oldukları coğrafyadaki siyasî ve idarî yapılarını ve hâkimiyetlerini kolaylaştıran amilleri anlayabilmek için, Selçuklu ordusunda komutanlık yapan mahalli idarecilerin rolünü tespit etmek elzemdir. Bu çalışmada Selçukluların İran ve Irak coğrafyalarında gerçekleştirdikleri fetihlerde bulunan, fetihler esnasında gösterdiği kahramanlık ve sadakatten dolayı Tuğrul Bey ve Alp Arslan dönemlerinde taltif edilen Hezâresb b. Bengîr adlı Selçuklu komutanının faaliyetleri ve Selçuklular ile münasebetleri üzerinde durulmuştur. Selçuklu fetihlerinde yer alan mahalli emîrlerin faaliyetlerini tespit etmenin Selçuklu hâkimiyetinin fethedilen şehirlerdeki devamlılığı hakkında ipuçları verebileceği kanaatindeyiz. Abstract: After the Battle of Dandanakan, the Seljuks accelerated their progress towards the West and reached the Anatolia gates and Bilad al-Sham region in less than a decade. During the conquering movements in question, they left the cities to the former rulers on condition that they fulfilled certain obligations. In this way, they strengthened their authority within the areas of dominance and benefited from the experience and capabilities of the current managers. The administration of cities such as Vasıt, Basra, Shiraz, Arracan and Khuzistan, located in Iran and Iraq on the Persian Gulf Coast, was under the domination of a local administrator Hazarasb b. Bangir. After arriving in Baghdad in 447 (1055), Tuğrul Bey left the administration of the cities to Hazarasb as it used to be. To understand the political and administrative structures of the Seljuks in the conquered geography and the factors that facilitate their domination, it is essential to determine the role of local administrators who were commanding the Seljuk Army. In this study, the activities of the Seljuk commander called Hazarasb b. Bangir conquering the regions of Iran and Iraq, and awarded because of bravery and loyalty during the reign of Tughril Beg and Alp Arslan were emphasized. We believe that determining the activities of the local governments in the Seljuk conquests could give clues about the continuity of the Seljuk domination in the conquered cities.
•The phase transition properties of the BEG model for spin-3/2 on the BL is considered.•Both effects of random crystal field and biquadratic exchange interactions are examined.•D (K) is either turned ...on with probability 1-p(q) or turned off with probability p(1-q).•Phase diagrams are obtained on the (K/J, kT/J) and (D/J, kT/J) planes on honeycomb lattice.•The model presents second and first order phase transitions, and also the tricritical points.
The phase transition properties of Blume–Emery–Griffiths (BEG) model for the spin-3/2 system are investigated on the Bethe lattice (BL) when the system is under the effect of both random crystal field (D) and biquadratic exchange interaction (K). These randomization effects are either turned on with probability 1−p (q) or turned off with probability p (1−q) for D and K, respectively. The phase diagrams are obtained on the (K/J, kT/J) and (D/J, kT/J) planes for given values of p and q when z=3.0 corresponding to honeycomb lattice. Both attractive (K > 0) and repulsive (K < 0) biquadratic exchange interaction values are considered to examine its effects on the BL. It is found that the model presents either second- or first-order phase transitions and also tricritical points. It is also found that the second-order phase lines follow the phase lines of regular spin-3/2 BEG model as K → ± ∞ for the phase diagrams on the (K/J, kT/J) planes.
A new genus and species, Battenispermum hirsutum, is described from the Early Cretaceous mesofossil flora of Catefica, Portugal. The new taxon is based on five ovulate structures with up to three ...seeds surrounded by an outer cup formed from partly fused bracts. The seeds are small, about 2.4–3.3 mm long and 1.0–1.6 mm wide, orthotropous with a chlamydospermous organisation. The nucellus is surrounded by a thin integument, a sclerenchymatic inner seed envelope and an additional outer envelope of four bracts, fused for most of their length. The seeds are three- or four-angled in transverse section and elliptical in lateral view with the free tips of the outer envelope forming short, apical projections around the micropyle. The outer surface of the inner seed envelope is almost smooth, while the abaxial surfaces of both inner and outer bracts of the compound ovulate structures are covered by a dense indumentum of long and stiff trichomes. Battenispermum hirsutum clearly belongs to the chlamydospermous BEG complex (Bennettitales-Erdtmanithecales-Gnetales), but it is distinguished from all previously described fossils by the presence of two distinct seed envelopes, a feature otherwise known only for extant Gnetum. The seeds of Battenispermum hirsutum differ, from those of extant Gnetum in other features, including the much simpler micropylar region.
•A new chlamydospermous seed is described from the Portuguese Cretaceous.•The new taxon Battenispermum hirsutum is distinctive in having two seed envelopes.•The new finding adds new information on the morphological variation in BEG seeds.•Supports the importance of the BEG group in the Early Cretaceous floras.
A new genus and species, Battenispermum hirsutum, is described from the Early Cretaceous mesofossil flora of Catefica, Portugal. The new taxon is based on five ovulate structures with up to three ...seeds surrounded by an outer cup formed from partly fused bracts. The seeds are small, about 2.4–3.3 mm long and 1.0–1.6 mm wide, orthotropous with a chlamydospermous organisation. The nucellus is surrounded by a thin integument, a sclerenchymatic inner seed envelope and an additional outer envelope of four bracts, fused for most of their length. The seeds are three- or four-angled in transverse section and elliptical in lateral view with the free tips of the outer envelope forming short, apical projections around the micropyle. The outer surface of the inner seed envelope is almost smooth, while the abaxial surfaces of both inner and outer bracts of the compound ovulate structures are covered by a dense indumentum of long and stiff trichomes. Battenispermum hirsutum clearly belongs to the chlamydospermous BEG complex (Bennettitales-Erdtmanithecales-Gnetales), but it is distinguished from all previously described fossils by the presence of two distinct seed envelopes, a feature otherwise known only for extant Gnetum. The seeds of Battenispermum hirsutum differ, from those of extant Gnetum in other features, including the much simpler micropylar region.
ABSTRACT
Frequently preserved in archaeological and palaeontological sites, the tiny size of small‐mammal remains favours percolations into underlying layers along stratigraphic sequences. This is ...one of the various post‐depositional processes that may affect the integrity of the original deposits and therefore the subsequent scientific interpretations. Recent developments in sample preparation offer the possibility of detecting intrusive episodes through the absolute dating of minute amounts of bone (down to 10 mg), meaning that isolated elements (such as mandibles in this case) are sufficient to obtain reliable radiocarbon dates if collagen is moderately to well preserved. The radiocarbon dates obtained here for small‐mammal bones (recovered from pre‐Bølling to recent deposits) and their comparison with previous dates obtained from other sources (large‐mammal bones, charcoal, botanical samples, etc.), with different protocols and instruments, illustrate the potential of small‐mammal dating to reveal (and eventually contribute a solution to) stratigraphical issues in different archaeological contexts.
The role of BEG 1,2-butanediol as a reducing agent in Co-based nanoparticle synthesis in the polyol process has not been well-detailed yet. So, we focused on the determination of the main active ...species derived from 1,2-butanediol (BEG) in Co-based nanoparticle synthesis and their reducing abilities through density functional theory (DFT) calculations. In the reaction medium, BEG is deprotonated by the hydroxyl ions introduced in the solution then oxidized by the metal ions. The progression of reduction and dissociation reactions of metal ions is relatively related to the reducing ability of polyols. Three species which are: dianion, monoanion and neutral molecule of BEG were considered in our investigation. The highest occupied orbital energy was estimated for the different configurations. Considering the experimental and theoretical studies, the monoanion state was suggested as the most active form. A comparative study was carried out between three polyols: BEG, PEG (1, 2-propanediol) and EG (Ethylen glycol), which are the most used solvents in Co-based nanoparticle synthesis. We showed that the highest occupied orbital energy of BEG monoanion state is relatively high compared to PEG and EG ones. Thus, BEG could reduce metal ions more easily by giving its electrons and its use can make the reaction kinetics faster.
Graphical Abstract
SYNOPSIS
The role of BEG 1,2-butanediol as a reducing agent in Co-based nanoparticle synthesis in polyol process has not been well-detailed yet. Our theoretical calculations show that the highest occupied orbital energy of BEG monoanion state is relatively high compared to most used solvents in Co-based nanoparticle synthesis. Thus, BEG could reduce metal ions more easily by giving its electrons and its use make the reaction kinetics faster.
We derive the exact Helmholtz free energy (HFE) of the standard and staggered one-dimensional Blume–Emery–Griffiths (BEG) model in the presence of an external longitudinal magnetic field. We discuss ...in detail the thermodynamic behavior of the ferromagnetic version of the model, which exhibits magnetic field-dependent plateaux in the z-component of its magnetization at low temperatures. We also study the behavior of its specific heat and entropy, both per site, at finite temperature. The degeneracy of the ground state, at T=0, along the lines that separate distinct phases in the phase diagram of the ferromagnetic BEG model is calculated, extending the study of the phase diagram of the spin-1 antiferromagnetic (AF) Ising model in S.M. de Souza and M.T. Thomaz, J. Magn. and Magn. Mater. 354 (2014) 205 5. We explore the implications of the equality of phase diagrams, at T=0, of the ferromagnetic BEG model with K|J|=−2 and of the spin-1 AF Ising model for D|J|>12.
•The exact thermodynamics of the D=1 standard and staggered Blume-Emery-Griffiths model.•The one-dimensional BEG model in the presence of a longitudinal magnetic field.•The degeneracy of the ground state, at T=0, of the ferromagnetic BEG model.•The degeneracy of the ground state, at T=0, of the ferromagnetic BEG model.•The degeneracy of the ground state, at T=0, of the anti-ferromagnetic spin-1 Ising model.•The ferromagnetic BEG model versus the AF spin-1 longitudinal Ising model at low temperature.
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