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Two classes of optimal quaternary sequences have been constructed by applying the sign alternation transform and Gray mapping to Legendre sequence pair, twin-prime sequence pair and GMW sequence pair. In this paper, a new method for investigating the linear complexity over finite field is proposed, and the exact values of the linear complexity over finite field F 4 and Galois ring Z 4 of the quaternary sequences are determined. The results show that their linear complexity are quite good. [ABSTRACT FROM AUTHOR]

Quaternary sequences with high linear complexity and N-adic complexity have been widespread concerned in cryptography. By using the Gray mapping, we construct a new class generalized cyclotomic quaternary sequences with period pq over Z 4 . We determine the linear complexity over F 4 and 4-adic complexity of the sequences. The results show that these sequences have high linear complexity and 4-adic complexity. [ABSTRACT FROM AUTHOR]

A quaternary sequence is said to be good if its maximum nontrivial autocorrelation is very low relative to its period. In this paper, we present some new classes of quaternary sequences with low autocorrelation of period N via two binary cyclotomic sequences, where N ≡ 1 (mod 4) is an odd prime. Furthermore, we determine the linear complexity and minimal polynomials of these quaternary sequences over F 2 2 as well. [ABSTRACT FROM AUTHOR]

R. Hofer and A. Winterhof proved that the 2-adic complexity of the two-prime (binary) generator of period pq with two odd primes p ≠ q is close to its period and it can attain the maximum in many cases. When the two-prime generator is applied to producing quaternary sequences, we need to determine the 4-adic complexity. It is proved that there are only two possible values of the 4-adic complexity for the two-prime quaternary generator, which are at least p q - 1 - max { log 4 (p q 2) , log 4 (p 2 q) } . Examples for primes p and q with 5 ≤ p , q < 10000 illustrate that the 4-adic complexity only takes one value larger than p q - max { log 4 (p) , log 4 (q) } , which is close to its period. So it is good enough to resist the attack of the rational approximation algorithm. [ABSTRACT FROM AUTHOR]

Sequence analysis of 2D seismic profiles and sediment data from the southwestern margin of Ulleung Basin reveals that the latest Neogene-Quaternary deposits comprise five depositional sequences (DS1–DS5), separated by erosional unconformities (H1–H5). The lower two sequences (DS1 and DS2), correlated with the Miocene strata, are acoustically characterized by hummocky and chaotic seismic facies, and were significantly deformed with several faults and folds. During the late Miocene, distinct geologic structures, including the Ulsan Structure (US), Dolgorae Thrust Belt (DTB), and Gorae Structure (GS) were also developed sequentially, which were closely related to formation of lower two sequences. However, the upper three sequences (DS3–DS5), belonging to the Plio-Quaternary strata, is acoustically characterized by well-stratified and prograding reflection configurations, and remained relatively undeformed. The tectonic movement related to the regional structures (US, DTB, and GS) was almost stopped since the Pliocene, whereas the part of the GS has been uplifted until the present. These results indicated that sedimentation for the upper three sequence since the Pliocene was mainly influenced by periodically repeated sea-level changes rather than tectonic activity. [ABSTRACT FROM AUTHOR]

In this paper, first we consider the linear complexity of quaternary sequences over the finite ring of order four and the finite field of order four. These sequences are constructed from new generalized cyclotomic classes modulo pn. Second, we study the linear complexity of new generalized cyclotomic binary sequences of period 2pn recently proposed by Ouyang et al. (Des. Codes Cryptogr.87(5), 1–12 2019). We generalized results presented in this work and discuss the author's conjecture. In conclusion, we again derive the linear complexity of quaternary sequences with period 2pn over the finite ring of order four and the finite field of order four. We use generalized cyclotomic classes modulo 2pn to define these sequences. [ABSTRACT FROM AUTHOR]

A quaternary sequence is said to be optimal if its odd-periodic autocorrelation magnitude equal to 2 for even length, and 1 for odd length. In this paper, we propose three constructions of optimal quaternary sequences: the first construction applies the inverse Gray mapping to four component binary sequences, which could be chosen from GMW sequence pair, twin-prime sequence pair, Legendre sequence pair, and ideal sequences; the second one generates optimal sequences from quaternary sequences with optimal even-periodic autocorrelation magnitude; the third one gives new optimal quaternary sequences by applying the sign alternation transform and Gray mapping to GMW sequence pair and twin-prime sequence pair. In particular, some proposed sequences have new parameters. [ABSTRACT FROM AUTHOR]

Pairs of complementary binary or quaternary sequences of length v such as Golay pairs, complex Golay pairs and periodic Golay pairs may be used to construct Hadamard matrices and complex Hadamard matrices of order 2v. We generalize these and define unitary Golay pairs and phased unitary Golay pairs of length v with entries in the kth roots of unity for any k≥2. This leads to a construction of Butson Hadamard matrices of order 2v over the kth roots of unity for even k. Ito conjectured that a central relative (4v, 2, 4v, 2v)-difference set exists in a dicyclic group of order 8v for all v≥1, and this is known to imply the Hadamard conjecture. With our construction we prove that Ito's conjecture also implies the stronger complex Hadamard conjecture. As a consequence, with this method we construct a complex Hadamard matrix of order 2v for any v for which Ito's conjecture is verified, in particular, any v≤46. [ABSTRACT FROM AUTHOR]

Two sequences are called a periodic (resp., an odd periodic) complementary pair if the sum of their periodic (resp., odd periodic) autocorrelation functions is a delta function. As a generalization of the well-known Golay sequence pairs, (odd) periodic complementary sequence pairs have important applications in radar, ranging, and communications. The objective of this letter is to present two generic constructions of quaternary periodic complementary pairs (PCPs). The first construction is based on binary odd PCPs and the Gray mapping. The second one is on the strength of the product sequences of a known quaternary sequence of odd length and a perfect quaternary sequence. Both constructions generate quaternary PCPs with new parameters which are not covered in the literature. [ABSTRACT FROM AUTHOR]

Highlights • Mixed cosolvents were used to modify the solubility behavior of a new dye in SCF-CO 2. • The solubility of the dye was notably improved in the presence of the mixed cosolvents. • The solubilities were correlated and validated successfully by typical semi-empirical models. • A new model was successfully developed for the quaternary system with high accuracy. • Better correlation was also obtained by the Chrastil and Del Valle-Aguilera models than others. Abstract Mixed cosolvents involving acetone and water were applied in hydrophobically supercritical carbon dioxide medium for modifying the solubility behavior of a new reactive disperse orange SCF-AOL2 dye. Then the equilibrium solubility of the dye solute in the quaternary system of supercritical carbon dioxide with the mixed cosolvents was measured at temperature from 333.2 K to 393.2 K and pressure from 8.0 MPa to 22.0 MPa with an equilibrium time of 60 min in a home-built batch circulation system. The experimental results show that a significant improvement of the dye solubility and its behavior was achieved in the presence of the mixed cosolvents in supercritical carbon dioxide, especially with the tested system pressure in different solubility isotherm curves. Moreover, the achieved experimental data were further correlated, validated and predicted successfully by employing several typically semi-empirical models for the quaternary system with mixed cosolvents. It is most important that a new and specially derived model based on the conventional and modified Mendez-Santiago–Teja ones was also proposed and successfully applied to the quaternary system with a significant improvement and highest accuracy than the employed other ones. Furthermore, better correlations were also achieved from the conventional Chrastil and the Del Valle-Aguilera models than other ones for the employed system. Graphical abstract Image, graphical abstract [ABSTRACT FROM AUTHOR]

In this paper, for any positive real number k, we introduce the k--Pell and k--Pell-Lucas quaternions and we consider certain matrices whose entries are Pell, Pell-Lucas, k--Pell and k--Pell-Lucas quaternions. We investigate the g--circulant, right circulant, left circulant and a special kind of a tridiagonal matrices whose entries are elements of these sequences. We present the determinant of these matrices and with the tridiagonal matrices we show that the determinant is equal to the nth term of the Pell, Pell-Lucas, k--Pell and k--Pell-Lucas quaternion sequences. [ABSTRACT FROM AUTHOR]

A strategy toward tetrapetalones was explored including a site-selective ethylenation of the silyl enol ether A to afford a quaternary stereocenter that serves in a stereogenic capacity. Regio- and diastereoselective reactions were observed in conjunction with the oxidative formation of cation B, which included subsequent selective formation of either carbon-oxygen or carbon-carbon bonds at the δ or ζ position on the seven-membered ring. The fourth ring was formed using a Stetter reaction. [ABSTRACT FROM AUTHOR]

Linear sand bodies with ridged or mounded morphology are commonly referred to as "sand ridges". Their origin may reflect a great variety of depositional processes and environments, although many examples from modern shelves include near-shore transgressive deposits formed during the last post-glacial sea level rise. These transgressive sand ridges, however, are not present on all the margins drowned during this interval, indicating that local environmental factors contribute to their formation and preservation. Transgressive sand ridges are recognized on the South Adriatic shelf in water depths between 90 and 120 m, where they overlay a major unconformity originated during the last glacial sea level fall and lowstand. In contrast, they are absent on the Central Adriatic shelf, where transgressive deposits above the glacial unconformity fill erosional scours without forming relief on the seafloor. The transgressive sand ridges on the South Adriatic shelf appear roughly elongated parallel to the bathymetric contour and are locally as thick as 15-20 m. Core data indicate an overall coarse-grained composition, with a relevant bioclastic component. Their limited distribution reflects the importance of local variation in shelf morphology and sediment sourcing at the onset of sea level rise. In particular, their deposition and preservation are favored in less subsiding shelf sectors characterized by higher gradients and tectonic relief, where transgressive erosion and reworking of pre-existing lowstand deposits is also more efficient. [ABSTRACT FROM AUTHOR]

Binary sequences with low odd correlation have important applications in communication systems to reduce interference. In this paper, using the interleaving technique, we present a generic connection between binary sequences with low odd correlation and quaternary sequences with low even correlation. As a result, some new binary sequences with optimal odd auto-correlation magnitude are obtained. Besides, two sets consisting of 2^n+1 binary sequences of period 2(2^n-1) with the maximum odd correlation magnitude 2^((n+1)/ 2)+2 are derived, which are the first two optimal classes of binary sequence sets achieving the Sarwate bound on the odd correlation magnitude in the literature. [ABSTRACT FROM PUBLISHER]

We determine explicit formulas for the number of representations of a positive integer n by quaternary quadratic forms with coefficients 1, 3, 5 or 15. We use the theory of modular forms. [ABSTRACT FROM AUTHOR]

The isothermal section of the Zn-Al-Mg-Si quaternary system at 450 °C with Zn fixed at 70 at.% has been determined by means of scanning electron microscopy, energy dispersive spectroscopy and x-ray diffraction. The results show that there exist the following equilibria regions in the isothermal section: Liq. + α-Al + MgZn + MgSi and Liq. + α-Al + MgSi + (Si) four-phase regions, and Liq. + α-Al + MgSi, Liq. + α-Al + MgZn, Liq. + MgZn + MgSi, Liq. + α-Al + (Si) and Liq. + MgZn + (Si) three-phase regions. Si is almost insoluble in MgZn and α-Al. The maximum solubility of Al and Zn in MgSi is 1.8 and 6.1 at.%, respectively. The maximum solubility of Al and Si in MgZn is 3.2 and 0.5 at.%, respectively. No ternary and quaternary compounds were found in this study. [ABSTRACT FROM AUTHOR]

A 3D high-resolution model of the Quaternary geological stratigraphic sequence in the Canterbury, New Zealand region is developed utilising datasets of over 500 high-quality water well logs from a database of 29,985, and over 370 near-surface cone penetration test (CPT) records from a database of 13,670. The model, developed using geostatistical Kriging, represents the complex interbedded regional Quaternary geology by characterising the boundaries between significant interbedded geological formations as 3D surfaces. The model is examined in the form of both geological surface contour maps and vertical cross sections, where the most evident trend identified is the easterly dip caused by the dominant alluvial deposition of terrestrial sediments. The developed 3D interbedded Quaternary stratigraphy model has several applications for hydrologic modelling, earthquake-induced ground motion simulations and seismic site characterisation. For the latter case, the role of the model in constraining surface wave analysis-based shear wave velocity profiling is illustrated. [ABSTRACT FROM AUTHOR]

In this letter, we present two new families of balanced quaternary sequences of period N = 2p with optimal three-level autocorrelation, where p = 4f+1 is an odd prime and has a quadratic partition of form either p = 4y^2+1 ( y is even) or p = 4+x^2 ( $x$ is odd). Our construction is based on the Chinese remainder theorem and cyclotomic classes of order four. [ABSTRACT FROM PUBLISHER]

Deep eutectic solvents (DES) are a new type of solvents that share some characteristics with Ionic Liquids while being cheaper, easier to prepare and, in some case, more readily biodegradable. This work reports a study on the Liquid-liquid Equilibria (LLE) of aqueous two-phase systems composed by DES + K 2 HPO 4 + water at 298.15 K. Various DES using choline chloride as hydrogen bond acceptor (HBA), and sugars as hydrogen bond donor (HBD), were prepared at several different proportions. An approach based on thermogravimetric analysis is here proposed to quantify the phase's components. The results show that the hydrogen bonds of DES are disrupted in aqueous solutions, leading to a differential partition of the HBA and HBD between the two phases, and to be coherent a quaternary ATPS must be considered. The NRTL model was used to describe the experimental LLE data with a low mean deviation. These systems were applied to Gallic Acid partition showing good extraction levels. [ABSTRACT FROM AUTHOR]

Gypsum beds host the majority of the caves in the north-eastern flank of the Apennines, in the Emilia Romagna region (Italy). More than six hundred of these caves have been surveyed, including the longest known epigenic gypsum cave systems in the world (Spipola-Acquafredda, ~11 km). Although this area has been intensively studied from a geological point of view, the age of the caves has never been investigated in detail. The rapid dissolution of gypsum and uplift history of the area have led to the long-held view that speleogenesis commenced only during the last 130 000 years. Epigenic caves only form when the surface drainage system efficiently conveys water into the underground. In the study area, this was achieved after the dismantling of most of the impervious sediments covering the gypsum and the development of protovalleys and sinkholes. The time necessary for these processes can by constrained by understanding when caves were first formed. The minimum age of karst voids can be indirectly estimated by dating the infilling sediments. U-Th dating of carbonate speleothems growing in gypsum caves has been applied to 20 samples from 14 different caves from the Spipola-Acquafredda, Monte Tondo-Re Tiberio, Stella-Rio Basino, Monte Mauro, and Castelnuovo systems. The results show that: (i) caves have been forming since at least ~600 kyr ago; (ii) the peak of speleogenesis was reached during relatively cold climate stages, when rivers formed terraces at the surface and aggradation caused paragenesis in the stable cave levels; (iii) ~200 000 years were necessary for the dismantling of most of the sediments covering the karstifiable gypsum and the development of a surface mature drainage network. Besides providing a significant contribution to the understanding of evaporite karst evolution in the Apennines, this study refines our knowledge on the timescale of geomorphological processes in a region affected by rapid uplifting. Copyright © 2016 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

We define a family of quaternary sequences over the residue class ring modulo 4 of length pq, a product of two distinct odd primes, using the generalized cyclotomic classes modulo pq and calculate the discrete Fourier transform (DFT) of the sequences. The DFT helps us to determine the exact values of linear complexity and the trace representation of the sequences. [ABSTRACT FROM AUTHOR]

Linear sand bodies with ridged or mounded morphology are commonly referred to as “sand ridges”. Their origin may reflect a great variety of depositional processes and environments, although many examples from modern shelves include near-shore transgressive deposits formed during the last post-glacial sea level rise. These transgressive sand ridges, however, are not present on all the margins drowned during this interval, indicating that local environmental factors contribute to their formation and preservation. Transgressive sand ridges are recognized on the South Adriatic shelf in water depths between 90 and 120 m, where they overlay a major unconformity originated during the last glacial sea level fall and lowstand. In contrast, they are absent on the Central Adriatic shelf, where transgressive deposits above the glacial unconformity fill erosional scours without forming relief on the seafloor. The transgressive sand ridges on the South Adriatic shelf appear roughly elongated parallel to the bathymetric contour and are locally as thick as 15–20 m. Core data indicate an overall coarse-grained composition, with a relevant bioclastic component. Their limited distribution reflects the importance of local variation in shelf morphology and sediment sourcing at the onset of sea level rise. In particular, their deposition and preservation are favored in less subsiding shelf sectors characterized by higher gradients and tectonic relief, where transgressive erosion and reworking of pre-existing lowstand deposits is also more efficient.

We study the rank and kernel of $${\mathbb {Z}}_4$$ cyclic codes of odd length n and give bounds on the size of the kernel and the rank. Given that a cyclic code of odd length is of the form $$\mathcal { C}= \langle fh, 2fg \rangle $$ , where $$fgh=x^n-1$$ , we show that $$\langle 2f \rangle \subseteq \mathcal { K}(\mathcal { C}) \subseteq \mathcal { C}$$ and $$\mathcal { C}\subseteq \mathcal { R}(\mathcal { C}) \subseteq \langle fh, 2g \rangle $$ where $$\mathcal { K}(\mathcal { C}) $$ is the preimage of the binary kernel and $$\mathcal { R}(\mathcal { C})$$ is the preimage of the space generated by the image of $$\mathcal { C}$$ . Additionally, we show that both $$\mathcal { K}(\mathcal { C})$$ and $$\mathcal { R}(\mathcal { C})$$ are cyclic codes and determine $$\mathcal { K}(\mathcal { C})$$ and $$\mathcal { R}(\mathcal { C})$$ in numerous cases. We conclude by using these results to determine the case for negacyclic codes as well. [ABSTRACT FROM AUTHOR]

The availability of enantiomerically enriched 1,3-dienyl substituted quaternary stereocenters is highly valuable for the synthesis of complex natural compounds. Despite great advances in the area of construction of alkenyl-substituted types, a general, practical catalytic system that works for enantioselective formation of 1,3-diene derivatives still remains to be developed. Herein, we disclose the first asymmetric Claisen rearrangement of allenyl vinyl ethers to access optically active β-ketoesters, containing branched 1,3-butadienyl substituted stereocenters. A variety of substrates bearing a range of useful functional groups were well tolerated, thus affording the corresponding products with excellent enantioselectivities (up to 99% ee) and high yields (up to 91%). [ABSTRACT FROM AUTHOR]

An explicit formula is given for the representation number of each of the 75 reduced, positive-definite, integral, primitive, quaternary quadratic forms , which belong to a genus with discriminant containing one and only one form class. [ABSTRACT FROM AUTHOR]

The flow characteristic temperatures of the selected quaternary CaO-MgO-SiO2-Al2O3 slags have been experimentally measured by performing softening and melting tests using a high temperature microscope in accordance with German standard 51730. An effective statistical model is developed through constructing empirical equations by regression analysis method to predict Softening temperature (ST), Hemispherical temperature (HT), and Flow temperature (FT) based on Al2O3 (25%-30%) content, CaO/SiO2 (C/S ratio: 0.9-1.4), and MgO (4%-12%) content. The effect of basicity, MgO and Al2O3 content on characteristic temperature are also studied. FactSage 6.4 data base is used to calculate liquidus temperature of the above quaternary slags and compared with the experimental and regression results. The experimental results show that, increase in Al2O3 content increases ST and HT while decreases FT of the slags. The ST, HT and FT increase with increase in C/S ratio. Increase in MgO content decreases both ST and HT while increases FT of the slags. The liquidus temperature obtained from FactSage 6.4 are found to correspond well with the experimental and regression data. Under the range of composition examined, a high Al2O3 (30%) and high C/S ratio (1.4) coupled with lowMgO (4%) content is beneficial for the blast furnaces running with high Alumina slags, as it ensures the formation of a short slag. [ABSTRACT FROM AUTHOR]

Background: Inference of active regulatory cascades under specific molecular and environmental perturbations is a recurring task in transcriptional data analysis. Commercial tools based on large, manually curated networks of causal relationships offering such functionality have been used in thousands of articles in the biomedical literature. The adoption and extension of such methods in the academic community has been hampered by the lack of freely available, efficient algorithms and an accompanying demonstration of their applicability using current public networks. Results: In this article, we propose a new statistical method that will infer likely upstream regulators based on observed patterns of up- and down-regulated transcripts. The method is suitable for use with public interaction networks with a mix of signed and unsigned causal edges. It subsumes and extends two previously published approaches and we provide a novel algorithmic method for efficient statistical inference. Notably, we demonstrate the feasibility of using the approach to generate biological insights given current public networks in the context of controlled in-vitro overexpression experiments, stem-cell differentiation data and animal disease models. We also provide an efficient implementation of our method in the R package QuaternaryProd available to download from Bioconductor. Conclusions: In this work, we have closed an important gap in utilizing causal networks to analyze differentially expressed genes. Our proposed Quaternary test statistic incorporates all available evidence on the potential relevance of an upstream regulator. The new approach broadens the use of these types of statistics for highly curated signed networks in which ambiguities arise but also enables the use of networks with unsigned edges. We design and implement a novel computational method that can efficiently estimate p-values for upstream regulators in current biological settings. We demonstrate the ready applicability of the implemented method to analyze differentially expressed genes using the publicly available networks. [ABSTRACT FROM AUTHOR]

We show that the density of quadratic forms in $n$ variables over $\mathbb {Z}_p$ that are isotropic is a rational function of pp, where the rational function is independent of pp, and we determine this rational function explicitly. When real quadratic forms in $n$ variables are distributed according to the Gaussian Orthogonal Ensemble (GOE) of random matrix theory, we determine explicitly the probability that a random such real quadratic form is isotropic (i.e., indefinite). As a consequence, for each $n$, we determine an exact expression for the probability that a random integral quadratic form in $n$ variables is isotropic (i.e., has a nontrivial zero over $\mathbb {Z}$), when these integral quadratic forms are chosen according to the GOE distribution. In particular, we find an exact expression for the probability that a random integral quaternary quadratic form is isotropic; numerically, this probability of isotropy is approximately 98.3%. [ABSTRACT FROM AUTHOR]

Understanding the Quaternary is a key to estimating what the Earth's climate will be like in the future. Such studies demand high-resolution analyses based on paleoclimatic proxy records of changing Earth's orbital forcing and solar insolation that affect the climate system. Quaternary diatom biostratigraphy and paleoceanography have been well established based on the Quaternary marine sequences obtained by piston coring and deep-sea drilling around the Japanese Islands. This paper firstly reviews the Quaternary diatom datum levels that are directly tied to magnetic polarity, and then the late Pleistocene and Holocene rhythmic fluctuations in Td' -derived SSTs (°C) which correlate with the Earth's orbital parameters, and finally reveals the large and abrupt climatic changes that have occurred around the Japanese Islands on centennial to millennial time scales. The main aim is to provide the results of Td' -SSTs (°C) based on the late Pliocene to Pleistocene sequences from three holes obtained by deep-sea drilling (DSDP-ODP). The main difference between Td' and Twt is that Twt gives 0.5 values to Xt (warm transitional taxa). Thalassiosira oestrupii is grouped with Xt in Twt but with warm-water species in Td' . Differences between the Twt and Td' -SSTs (°C) curves at Hole 436 are unremarkable. The remarkable variations of paleo-temperatures based on Td' -SSTs (°C) show four conspicuous episodes which correspond to the double precession cycle of MIS 11. In the Japan Sea, the Twt ratio remarkably decreases at 2.6 Ma due to a large increase in cold-water taxa, and indicates the beginning of the glacial age defined as the Pliocene/Pleistocene boundary. Both Twt and Td' -SSTs (°C) increase at 2.60–2.0 Ma, and coincide with the lithologic change from diatom-bearing clay with few dark-colored layers to fine-grained sediments with distinct dark–light colored cycles. Wavelet analysis of Td' -SSTs (C) at Site 798 indicates a reversed saw-tooth pattern of 48 to 24-ky periods during 1.2–0.7 Ma, and 24 to 12-ky periods during 0.7–0 Ma, resulting in a change from longer to shorter cycles. These fluctuations correlate with the Earth's orbital parameters and climatic changes on a millennial time scale. [ABSTRACT FROM AUTHOR]

Sequences with high linear complexity play a fundamental part in cryptography. In this study, the authors construct general forms of Whiteman's generalised cyclotomic quaternary sequences with period 2pm +1qn +1 of order two over 𝔽4 and give the linear complexity of the proposed sequences. The conclusions reveal that such sequences have good balance property and high linear complexity. [ABSTRACT FROM AUTHOR]

ABSTRACT A detailed study of the uppermost 221 m of drill core LYH-1 - located in the northern part of the Weihe Basin - reveals considerable environmental variety over the past 1 Myr. Studied parameters include lithofacies, sedimentological properties and micropalaeontological content of selected core-samples. Present-day environments in the research area have been used as analogues for past conditions. The palaeoenvironments documented in the sedimentary record are interpreted as shallow lakes, fluvial settings, soils and aeolian environments. The temporal variation of the environments indicates a rapid alternation between climate-driven wet and dry phases, suggesting that these fluctuations are related to changes in monsoon intensity. However, on a larger temporal scale, the sedimentation and accumulation of water is also affected by local tectonics. End-member modelling shows that the siliciclastic grain-size distributions can be ascribed to the mixing of six distinct end-members. Most of the sediments in core LYH-1 have similar characteristics to the loess deposits from the Central Loess Plateau. However, the much higher sedimentation rates and sedimentary structures suggest that these sediments consist for a large part of fluvially reworked loess. A broad subdivision of the core into three main intervals can be made, tentatively dated by magnetostratigraphy. From 162 to 221 m (690-1000 ka), brackish wetland conditions with a regular influence from fluvial and/or distal alluvial fan systems prevailed. The interval 90-162 m (330-690 ka) shows more terrestrial settings with occasional hypersaline lakes. From 0 to 90 m (0-330 ka), the environment was a shallow wetland, albeit with a relatively low diversity of aquatic and terrestrial microfossils compared to the lower interval. [ABSTRACT FROM AUTHOR]

The solubilities of the quaternary system K 2 SO 4 –MgSO 4 –(NH 4 ) 2 SO 4 –H 2 O were measured by isothermal method at 25 °C and their dry salt phase diagrams were plotted. The results indicated that, at 25 °C, the solubility phase diagram of this quaternary system consists of seven crystallization regions, those are single-salt crystallization region MgSO 4 ·7H 2 O, (NH 4 ) 2 SO 4 , and K 2 SO 4, complex salt crystallization region MgSO 4 ·(NH 4 ) 2 SO 4 ·6H 2 O, MgSO 4 ·K 2 SO 4 ·6H 2 O, solid solution crystallization region (K 1−n , NH 4n ) 2 SO 4 (n:0.143–0.893) and (K 1−n , NH 4n ) 2 SO 4 ·MgSO 4 ·6H 2 O (n:0.552–0.973), respectively. The extended Pitzer model was derived and applied to the phase equilibrium calculation of system K 2 SO 4 –MgSO 4 –(NH 4 ) 2 SO 4 –H 2 O and its sub-systems at 25 °C. The results showed that the calculated values were consistent with experimental results well. The study on the quaternary system K 2 SO 4 –MgSO 4 –(NH 4 ) 2 SO 4 –H 2 O provides a foundation for the N–Mg–K–S compound fertilizers preparation. [ABSTRACT FROM AUTHOR]

Study of polymer blends that fulfill the current engineering demand has been increased in the last years and multicomponent blends are still a challenge, but increasing the number of components will lead to further complications. We correlated the differences between morphology and blending sequence in quaternary blends of polyolefin with polystyrene, following the available theories that related viscosity and morphology. It was found that high viscous matrices enhance deformation and breakup processes, displaying fibrillar morphologies and finer dispersions. The blending sequence improves the mixing first, by putting all the polyolefin into a ternary blend and after that, adding the polystyrene. [ABSTRACT FROM AUTHOR]

Tang et al. and Lim et al. presented ways to construct balanced quaternary sequences with even period and optimal autocorrelation value by inverse Gray-mapping of binary sequences with optimal autocorrelation value. In this article, we consider quaternary sequences constructed from binary Legendre or Hall's sextic sequence by these methods. We derive the linear complexity of series of balanced quaternary sequences with optimal autocorrelation value over the finite ring of four elements. [ABSTRACT FROM AUTHOR]

The regio- and stereoselective formation of stereodefined polysubstituted silyl ketene aminals is easily achieved through selective combined carbometalation–oxidation–silylation reactions. These substrates are ideal candidates for Mukaiyama aldol reactions with aliphatic aldehydes as they give the aldol products with a quaternary carbon stereocenter α to the carbonyl groups in outstanding diastereoselectivities. [ABSTRACT FROM AUTHOR]

An [ n , k , d ] q code C is l -extendable if C can be extended to an [ n + l , k , d + l ] q code. We give some new sufficient conditions for the l -extendability of [ n , k , d ] 4 codes with d ≢ 0 ( mod 4 ) using the known results about odd sets in PG ( k − 1 , 4 ) . The 3-extendability of quaternary linear codes is investigated through their diversities for the first time. [ABSTRACT FROM AUTHOR]

The Willandra Lakes complex is one of the few locations in semi-arid Australia to preserve both paleoenvironmental and Paleolithic archeological archives at high resolution. The stratigraphy of transverse lunette dunes on the lakes’ downwind margins record a late Quaternary sequence of wetting and drying. Within the Willandra system, the Lake Mungo lunette is best known for its preservation of the world’s oldest known ritual burials, and high densities of archeological traces documenting human adaptation to changing environmental conditions over the last 45 ka. Here we identify evidence at Lake Mungo for a previously unrecognised short-lived, very high lake filling phase at 24 ka, just prior to the Last Glacial Maximum. Mega-lake Mungo was up to 5 m deeper than preceding or subsequent lake full events and represented a lake volume increase of almost 250%. Lake Mungo was linked with neighboring Lake Leaghur at two overflow points, creating an island from the northern part of the Mungo lunette. This event was most likely caused by a pulse of high catchment rainfall and runoff, combined with neotectonic activity which may have warped the lake basin. It indicates a non-linear transition to more arid ice age conditions. The mega-lake restricted mobility for people living in the area, yet archeological traces indicate that humans rapidly adapted to the new conditions. People repeatedly visited the island, transporting stone tools across water and exploiting food resources stranded there. They either swam or used watercraft to facilitate access to the island and across the lake. Since there is no evidence for watercraft use in Australia between initial colonization of the continent prior to 45 ka and the mid-Holocene, repeated visits to the island may represent a resurrection of waterfaring technologies following a hiatus of at least 20 ky. [ABSTRACT FROM AUTHOR]

In this paper, several constructions of binary and quaternary complete sequences and sequence pairs are presented. Based on singed shift sequence and interleaving technique, several binary and quaternary complete sequences and sequence pairs are generated by employing binary complete sequence, binary complete complementary sequence mate and binary complete sequence pair as the initial sequence. By means of interleaving iteration, more complete sequences and sequence pairs with novel parameters can be obtained. [ABSTRACT FROM AUTHOR]

We studied the phylogeographic structuring of the edible dormice populations occupying the landbridge Adriatic islands which were isolated from the mainland after a transgression of glacial meltwater at about 10 kya. The edible dormouse is well nested into a system-wide biogeography of the archipelago, presumably the consequence of its in situ persistence since the insularisation of the entire system. If so, the genetic profile of island populations was not affected by the presumed population bottleneck at ∼2 kya and possibly retained an ancestral genetic diversity which eroded on the mainland. To test the hypothesis, we explored a fragment of a cytochrome b gene in 50 dormice from six islands and a further 10 individuals from two eastern Adriatic peninsulas (Istria and Pelješac), one locality in Serbia and three localities in Macedonia. Two new haplotypes from Macedonia clustered into the Macedonian phylogeographic lineage, while the remaining 9 haplotypes formed an unsupported sublineage (the Adriatic haplogroup) within a widespread European lineage. Six Adriatic haplotypes were endemic to a particular island and only one single haplotype was shared between the islands and the mainland. Four islands only had endemic haplotypes and only the widespread haplotype was recorded on a further two islands. A mere 1–2 mutational steps separated the endemic island haplotypes from the widespread haplotype which concurs with the postulated recent population expansion of the European lineage. On the other hand, the suggested timing of the event (i.e. 2 kya) cannot be comfortably accommodated into the environmental dynamics of the Adriatic region since the Last Glacial Maximum. [ABSTRACT FROM AUTHOR]

A practical sequence involving a noncryogenic stereospecific boronate rearrangement followed by a robust formylation with an in situ generated DCM anion has been developed for the asymmetric construction of an all-carbon quaternary stereogenic center of a FLAP inhibitor. The key boronate rearrangement was rendered noncryogenic and robust by using LDA as the base and instituting an in situ trapping of the unstable lithiated benzylic carbamate with the boronic ester. A similar strategy was implemented for the DCM formylation reaction. It was found that the 1,2-boronate rearrangement for the formylation reaction could be temperature-controlled, thus preventing overaddition of the DCM anion and rendering the process reproducible. The robust stereospecific boronate rearrangement and formylation were utilized for the practical asymmetric synthesis of a chiral quaternary FLAP inhibitor. [ABSTRACT FROM AUTHOR]