Minor Expansion Research Articles

Исследование механизма повышения стабильности ствола скважины при бурении трещиноватых аргиллитов

The paper presents the relevance of enhancing wellbore stability by developing and applying efficient drilling fluid compositions for well constructions in fractured argillite. In the process of well constructions, there comes a range of complications associated with instability of rocks forming borehole walls, which sometimes results in lower penetration rates, higher construction costs and well abandonment. Often, drilling problems occur at drilling through mudrocks that account for up to 70 % of field sections. When using water-base drilling fluids, the mudrock swelling due to the contact with the fluid dispersion medium adversely affects the drilling process and can significantly increase well construction costs. The accumulation of wellbore cavings inhibits well circulation, causes landing of drilling tools and may result in tool sticking. An analysis of drilling problems in fractured argillite is presented; the mechanisms affecting open hole stability in the fractured argillite deposits are shown. The use of potassium chloride is recommended to enhance the stability of argillite-formed borehole walls. The results are supported by experimental studies using the Chenevert method, as well as fracture propping tests. When the argillite sample was placed in potassium chloride (KCl) solution, there was a minor fracture expansion and propagation over the entire sample length, which is a positive result. To enhance wellbore stability, further study approaches are proposed: upgrading mud by adding inhibiting compounds, such as salt solutions in combination with high-molecular polymer compositions.

The biomechanical impact of hip movement on iliofemoral venous anatomy and stenting for deep venous thrombosis

BackgroundStenting of the iliofemoral vein may be an effective treatment to improve post-thrombotic symptoms. Iliofemoral vein stents have requirements different from those of lower extremity artery stents, and there is a paucity of literature regarding the biomechanical motion of the iliofemoral vein. MethodsIn a novel cadaveric model, stents were bilaterally inserted into the veins in the iliofemoral region. The veins were pressurized and underwent computed tomography angiography at various hip angle positions. In addition, 21 patients with iliofemoral vein disease had supine computed tomography angiography before and after stenting. The stents and vasculature were reconstructed into three-dimensional geometric models to quantify stent deformations and the interaction between the iliofemoral vein, inguinal ligament, and pubis bone due to hip flexion-extension. ResultsIn the cadavers, from supine to 30 to 45 degrees and 50 to 75 degrees of hip flexion, iliofemoral vein stents became less compressed (4.5% minor diameter expansion), and the inguinal ligament was separated from the iliofemoral veins by 1 to 3 cm in all hip positions. In the patients, the pubis compressed 47% of femoral veins; 78% were within 3 mm of the pubis. There was also evidence of contrast-enhanced flow disruption at the superior ramus. ConclusionsThe cadaver and clinical evidence shows that contrary to widely accepted dogma, the common femoral vein is not compressed by the inguinal ligament during hip flexion but rather by the superior ramus of the pubis during hip extension, which may have an impact on future stent design and influence deep venous thrombosis treatment strategies.

Improvements of properties of alumina-silica refractory castables by alumina-coated aluminum powders

Castables have been widely used in repairing furnace linings owing to their numerous verified benefits. Al2O3 coated Al powders (ACAPs) were prepared to prevent their hydration during castable preparing. The effect of ACAPs on the properties of cement-bonded Al2O3–SiO2 refractory castables under simulated coke drying quenching (CDQ) conditions was investigated. The results show AlN plate in situ formed at 800 °C and grew into whiskers and fibers at 1000 °C because metal Al melted and expanded which resulted to the cracks of Al2O3 shell, Al liquid flew out and directly reacted with N2. The strength and thermal shock resistance of castable samples were greatly improved by adding ACAPs while keeping minor expansion. The toughness of castables was greatly enhanced after fired at 1000 °C owe to AlN whiskers and fibers in situ synthesized in the castable matrix. The optimum amount of ACAPs is 9 wt % which provides higher strength and excellent toughness.

Complete chloroplast genomes of all six Hosta species occurring in Korea: molecular structures, comparative, and phylogenetic analyses

BackgroundThe genus Hosta is a group of economically appreciated perennial herbs consisting of approximately 25 species that is endemic to eastern Asia. Due to considerable morphological variability, the genus has been well recognized as a group with taxonomic problems. Chloroplast is a cytoplasmic organelle with its own genome, which is the most commonly used for phylogenetic and genetic diversity analyses for land plants. To understand the genomic architecture of Hosta chloroplasts and examine the level of nucleotide and size variation, we newly sequenced four (H. clausa, H. jonesii, H. minor, and H. venusta) and analyzed six Hosta species (including the four, H. capitata and H. yingeri) distributed throughout South Korea.ResultsThe average size of complete chloroplast genomes for the Hosta taxa was 156,642 bp with a maximum size difference of ~ 300 bp. The overall gene content and organization across the six Hosta were nearly identical with a few exceptions. There was a single tRNA gene deletion in H. jonesii and four genes were pseudogenized in three taxa (H. capitata, H. minor, and H. jonesii). We did not find major structural variation, but there were a minor expansion and contractions in IR region for three species (H. capitata, H. minor, and H. venusta). Sequence variations were higher in non-coding regions than in coding regions. Four genic and intergenic regions including two coding genes (psbA and ndhD) exhibited the largest sequence divergence showing potential as phylogenetic markers. We found compositional codon usage bias toward A/T at the third position. The Hosta plastomes had a comparable number of dispersed and tandem repeats (simple sequence repeats) to the ones identified in other angiosperm taxa. The phylogeny of 20 Agavoideae (Asparagaceae) taxa including the six Hosta species inferred from complete plastome data showed well resolved monophyletic clades for closely related taxa with high node supports.ConclusionsOur study provides detailed information on the chloroplast genome of the Hosta taxa. We identified nucleotide diversity hotspots and characterized types of repeats, which can be used for developing molecular markers applicable in various research area.

The τ-function of the Ablowitz-Segur family of solutions to Painlevé II as a Widom constant

The τ-functions of certain Painlevé equations (PVI, PV, and PIII) can be expressed as Fredholm determinants. Furthermore, the minor expansion of these determinants provides an interesting connection to random partitions. This paper is a step toward understanding whether the τ-function of Painlevé II has a Fredholm determinant representation. The Ablowitz-Segur family of solutions are special one parameter solutions of Painlevé II, and the corresponding τ-function is known to be the Fredholm determinant of the Airy kernel. We develop a formalism for open contour in parallel to the one formulated in terms of a suitable combination of Toeplitz operators called the Widom constant and verify that the Widom constant for the Ablowitz-Segur family of solutions is indeed the determinant of the Airy kernel. Finally, we construct a suitable basis and obtain the minor expansion of the Ablowitz-Segur τ-function.

Preserving butterfly diversity in an ever‐expanding urban landscape? A case study in the highlands of Chiapas, México

We examined the relationship between landscape structure and composition, geographic ranges, microhabitat characteristics and the diversity of butterflies (Papilionidae, Nymphalidae, Pieridae, Hesperiidae, Lycaenidae) in an expanding urban landscape in the highlands of Chiapas, Mexico. Between 2001 and 2016, mountain wetlands, secondary forest, and agro-pasture land, have declined significantly in area covered due to increasing housing activities and expansion of roads and conversion of land for cattle activity. Cloud forest exhibited a minor positive expansion in area, mostly through forest regeneration. In total, we recorded 3630 individuals from 90 species at key sites spanning natural, semi-natural and urban areas. A rarefaction curve analysis for local richness indicated that mountain wetland sites recorded the highest butterfly diversity. Logistic regression analyses suggested that species with narrow geographic ranges could be associated to cloud-forest sites, and that species with relatively more widespread distributions in the Neotropics were more likely to be classified as occurring in mountain wetland habitats. This was confirmed by IndVal analyses from which we identified 39 butterfly species as potential reliable land-cover indicators. Furthermore, canonical correspondence analyses suggested significant associations for the values of butterfly abundance and microhabitat variables such as canopy cover, open areas, presence of grasses, bare soil or rocks. It is a matter of urgency that should put in place monitoring schemes to assess occupancy and change so we can assess changes in the status of butterfly species in rapidly-expanding urban landscapes in tropical Mexico.

Quantitative organic-walled dinoflagellate cyst stratigraphy across the Eocene-Oligocene Transition in the Gulf of Mexico: A record of climate- and sea level change during the onset of Antarctic glaciation

The Eocene – Oligocene Transition (EOT, 34–33.5 Ma) marks a major transition in Cenozoic climate evolution through the relatively rapid establishment of a continental-scale ice sheet on Antarctica. The EOT is characterized by two 200 kyr spaced shifts (termed EOT-1 and Oi-1) in the oxygen isotopic composition (δ18O) of benthic foraminifera, representing both changes in continental ice-volume and temperature. Estimates of the timing and magnitude of these changes during this critical phase in Earth’s climatic evolution are controversial. Here we present marine palynological assemblage data, in particular of organic-walled dinoflagellate cysts (dinocysts), across a classic upper Eocene to lower Oligocene neritic succession cored in Alabama, USA; the Saint Stephens Quarry (SSQ) borehole. These palynological data combined with lithological information allow the identification of three sequence boundaries across the EOT. Critically, we identify a sequence boundary at the level corresponding to the EOT-1. Integrated sea level and paleotemperature records show that EOT-1 primarily represents cooling with some minor and transient continental ice sheet expansion. Furthermore, we identify a significant hiatus, likely caused by major sea level fall at the base of Magnetochron C13n that corresponds to the Oi-1 shift. This clarifies the δ18O records from SSQ that essentially lack the expected pronounced shift to positive δ18O values so characteristic for Oi-1. Furthermore, we document originations and extinctions of potentially temperature-sensitive dinocysts associated with the EOT-1. In contrast, the Oi-1 does not stand out as period of substantial dinoflagellate turnover. The combined results illustrate that major cooling, limited and transient ice growth and major biotic change were occurring before the full-size expansion of the Antarctic cryosphere. © 2018 The Authors.

Controlled Molar Inclination during Maxillary Dental Expansion Using a Straight Rectangular Archwire

Purpose The purpose of this study was to examine whether the amount of transversal dental expansion, controlled using a straight rectangular beta-titanium alloy (TMA®) wire, has an influence on changes in maxillary first molar inclination. Materials and Methods Twenty patients requiring bilateral maxillary dental arch expansion were treated using a 0.018”-slot preadjusted edge-wise fixed appliance. Once leveled and aligned, the maxillary dental arches were expanded using a 0.016” × 0.022” straight TMA® wire. Changes in arch width and maxillary first molar inclination were assessed before (T0) and after (T1) expansion using three-dimensional scanned models. Mann–Whitney U-test, Wilcoxon signed-rank test, and Kruskal–Wallis test were used, where appropriate, to compare changes between and within groups. Results Intermolar width expanded at a rate of 0.8 ± 0.3 mm/month, and first molar buccal crown tipping occurred at 2.1° ± 1.2° (P < 0.05). Changes in inclination between minor expansion (1.0–2.5 mm) and moderate expansion (2.6–4.0 mm) groups were not statistically significant (1.8 ± 0.5 vs. 2.2 ± 1.2; P > 0.05). Conclusions Use of a straight rectangular TMA® wire in conjunction with a fixed orthodontic appliance successfully expanded the maxillary dental arch. The amount of expansion had no effect on molar inclination.

Abstract 991: Development and characterization of patient derived xenografts from central nervous system metastasis reveal minor clone expansion linked with aggressive tumor behavior

Abstract Despite recent advances in cancer therapy, options for central nervous system metastasis (CM) remain limited and patient outcomes are dismal. The lack of tumor models that reflect the heterogeneity and complexity of human CM tumors is a barrier to understanding the underlying biology and to developing novel therapies. Here, we report the development and characterization of 39 patient derived xenograft (PDX) models of CM tumors with histological subtypes representing the disease spectrum. The PDX models successfully grew both in the flank and brains of mice, and retained their histology regardless of the site of implantation. Brain metastasis also formed in 5/12 models after intra-cardiac injection. Multi-omic analysis of the PDX tumor and the patient-matched CM tumor showed that PDXs largely retained the molecular profiles of the tumor from which they were derived, including the retention of aberrations in key driver genes and signaling pathways. PDXs differed primarily from the ungrafted patient tumors by a downregulation in immunity-related pathways, which was expected due to the use of an immuno-compromised host, arguing for the validity of using the flank as a site of implantation. Integrated analysis of mutations and gene expression changes in CM revealed an upregulation of neuronal signaling and DNA damage response, and downregulation of calcium signaling and inflammation. We also assessed the clonal evolution of the PDX from the original patient CM by tracing variant allele frequencies in copy number neutral regions. We found that the PDX tumors were heterogeneous and comprised of multiple tumor clones that were either unique or in common with the original tumor, and displayed evidence of clonal expansion. Two PDXs that underwent phylogeny assessment showed evidence of minor clone expansion. One such PDX was a tumor from a Her2+ breast cancer (CM13), which largely did not molecularly resemble its matched patient tumor but was confirmed to have some shared expressed variants. The PDX was nearly copy number neutral, which included loss of the Her2 amplicon, and had few mutations compared with its parent tumor. Most noteworthy, is that CM13 displayed unique molecular patterns, aggressive growth and was highly metastatic in vivo. From the flank, it led to multiple metastases, including micrometastasis in the brain. This suggests that minor clone takeover may confer tumor aggressiveness and potentiate brain metastasis. The large and diverse repertoire of PDXs developed and characterized in this study provides a new set of tools that will help deepen our understanding of CM and improve preclinical testing for CM therapies. Our data also show that expansion of minor clones could confer aggressive tumor behavior and may be important in tumor evolution in PDX models and human cancers. Citation Format: Ben Yi Tew, Christophe Legendre, Tim Triche, Gerald C. Gooden, Kyle N. Johnson, Rae Anne Martinez, Emanuel F. Petricoin, Mariaelena Pierobon, Joyce O'Shaughnessy, Cindy Osborne, Mark A. Schroeder, Daniel J. Ma, Mark Bernstein, Jann N. Sarkaria, Steven A. Toms, Bodour Salhia. Development and characterization of patient derived xenografts from central nervous system metastasis reveal minor clone expansion linked with aggressive tumor behavior [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 991.

Long-term behaviors of phosphate-based rapid repairing material for concrete shafts in coal mines.

Concrete structures in shaft linings are apt to deteriorate prematurely and therefore prompt restoration is required. In considering this, desulphurization fly ash and machine-made tuff sand are employed to fabricate a phosphate-based rapid repairing material. The long-term efficiency of the material is evaluated based on combined factors, so drying shrinkage, interfacial bonding strength, corrosion resistance, and combustibility of the specimens are tested and researched in this paper. Experimental results showed that, under a dry circumstance, the material goes through a minor expansion at an early stage. It goes into a stage of rapid contraction after one day and a stable contraction after seven days. After 28 days, the total deformation is 67 micro-strains. On the other hand, the fabricated material manifests an excellent mechanical property. The one hour bending strength and compressive strength were 9.2 MPa and 32.6 MPa, respectively. A long-term mine water flushing simulation demonstrates that only 10% bending strength is lost and the corrosion resistance coefficient stays above 0.8, so a very good corrosion resistance is thus achieved. What is more, this repairing material retains its stability even at a high temperature of 1000°C, revealing its good thermo-stability. All these prominent properties make it a good prospective material for real restoration applications.

Temperature measurement and machining damage in slotting of multidirectional CFRP laminate

ABSTRACTCompared to metallic materials, carbon fiber-reinforced plastics (CFRPs) have lower thermal conductivity and minor thermal expansion coefficient. Despite this, their machining can generate accuracy errors if the cutting temperature is not controlled. In this paper, an experimental study of slotting of multidirectional CFRP laminate (G803/914) with three micrograin carbide burr tools with different geometries is considered in order to investigate tool-workpiece contact point temperature, chip temperature, machined surface damage, subsurface defects and tool degradation. The experiment is made on a computer numerical control (CNC) machine with cutting speed ranging from 80 to 200 m/min and feed per tooth from 0.008 to 0.060 mm/rev/tooth. The data were analyzed in order to establish empirical models showing the dependence of cutting temperature on tool geometry and cutting conditions. Based on the results, it is concluded that cutting speed is the factor influencing cutting temperature the most, the heat generated during slotting is removed mainly by chips and the chip temperature is greater than the tool-workpiece contact temperature of about 18.5°C on average for the three burr tools.

Coastal dynamics of Northern Australia – Insights from the Landsat Data Cube

We demonstrate the capacity of detailed time-series of remotely sensed data to identify notable changes and trends in coastal morphology and vegetation over the last three decades, and illustrate how these data can help identify drivers of change, and areas that require further investigation. Time-series analysis (1987–2016) of the Australian Landsat archive is enabled by the Australian Geoscience Data Cube (AGDC), in which the data has been processed and restructured. We use Hovmoller plots to graphically display this time series for three test sites on the tropical coast of northern Australia. Initial results reveal distinct differences between sites: 1. Abrupt loss of mangrove cover (2004, 2006), which clearly relates to the passage of cyclones (Junction Bay); 2. Gradual seawards expansion of mangrove (1987–1996), and subsequent rapid narrowing of the mangrove zone (2013–2016; Burketown); 3. Minor seawards expansion of mangrove (1987–2004) in a stable embayment (Darwin Harbour). The density and duration of the time series enables clear links to be made to recorded events (e.g. cyclones), and identifies focus areas that exhibit unprecedented patterns of change (e.g. loss of mangrove) where regional or global environmental processes may be driving local change.

Observing Framework Expansion of Ordered Mesoporous Hard Carbon Anodes with Ionic Liquid Electrolytes via in Situ Small-Angle Neutron Scattering

The reversible capacity of materials for energy storage, such as battery electrodes, is deeply connected with their microstructure. Here, we address the fundamental mechanism by which hard mesoporous carbons, which exhibit high capacities versus Li, achieve stable cycling during the initial “break-in” cycles with ionic liquid electrolytes. Using in situ small-angle neutron scattering we show that hard carbon anodes that exhibit reversible Li+ cycling typically expand in volume up to 15% during the first discharge cycle, with only relatively minor expansion and contraction in subsequent cycles after a suitable solid electrolyte interphase (SEI) has formed. While a largely irreversible framework expansion is observed in the first cycle for the 1-methyl-1-propypyrrolidinium bis(trifluoromethanesulfonyl)imide (MPPY.TFSI) electrolyte, reversible expansion is observed in the electrolyte lithium bis(trifluoro-methanesulfonyl)imide (LiTFSI)/1-ethyl-3-methyl-imidazolium bis(trifluoromethanesulf-onyl)imide (EMIM.TFSI) related to EMIM+ intercalation and deintercalation before a stable SEI is formed. We find that irreversible framework expansion in conjunction with SEI formation is essential for the stable cycling of hard carbon electrodes.

ReaCog, a Minimal Cognitive Controller Based on Recruitment of Reactive Systems.

It has often been stated that for a neuronal system to become a cognitive one, it has to be large enough. In contrast, we argue that a basic property of a cognitive system, namely the ability to plan ahead, can already be fulfilled by small neuronal systems. As a proof of concept, we propose an artificial neural network, termed reaCog, that, first, is able to deal with a specific domain of behavior (six-legged-walking). Second, we show how a minor expansion of this system enables the system to plan ahead and deploy existing behavioral elements in novel contexts in order to solve current problems. To this end, the system invents new solutions that are not possible for the reactive network. Rather these solutions result from new combinations of given memory elements. This faculty does not rely on a dedicated system being more or less independent of the reactive basis, but results from exploitation of the reactive basis by recruiting the lower-level control structures in a way that motor planning becomes possible as an internal simulation relying on internal representation being grounded in embodied experiences.

Energiesystemtransformation – räumliche Politik und Stromnetzplanung


 Energy politics tend to organize the balance between power production and power consumption at the international scale as good as possible, leaving the site selection for new power or storage plants to pan-European competition. As grid costs are paid for by consumers, such policy causes an increasing spatial concentration of power plants on most beneficial sites and a very extensive transmission grid expansion. In civil society in contrast, the intent of “energy transition” is often linked with aims of placing power production units close to consumption to regional balance divergence between power production and consumption patterns. Supporters expect a minor transmission grid expansion requirement from such a “decentralized energy transition”.
 Against this background the article addresses the practice of grid planning in Germany as a focal point of the spatial energy policy. In this regard the role of transmission capacity planning is crucial. It is directly based on aims and measures of energy policy and thereby connects energy policy with transmission grid planning. The Federal Network Agency meanwhile has established sensitivity analysis as an instrument to check policy options with regard to their impacts on grid extension requirements. This instrument however could also be used to consider alternative paths in order to develop a systematic weighting regulation approach with integrated public participation based on well-grounded impact analysis.

Second-order two-scale finite element algorithm for dynamic thermo–mechanical coupling problem in symmetric structure

The new second-order two-scale (SOTS) finite element algorithm is developed for the dynamic thermo-mechanical coupling problems in axisymmetric and spherical symmetric structures made of composite materials. The axisymmetric structure considered is periodic in both radial and axial directions and homogeneous in circumferential direction. The spherical symmetric structure is only periodic in radial direction. The dynamic thermo-mechanical coupling model is presented and the equivalent compact form is derived. Then, the cell problems, effective material coefficients and the homogenized thermo-mechanical coupling problem are obtained successively by the second-order asymptotic expansion of the temperature increment and displacement. The homogenized material obtained is manifested with the anisotropic property in the circumferential direction. The explicit expressions of the homogenized coefficients in the plane axisymmetric and spherical symmetric cases are given and both the derivation of the analytical solutions of the cell functions and the quasi-static thermoelasticity problems are discussed. Based on the SOTS method, the corresponding finite-element procedure is presented and the unconditionally stable implicit algorithm is established. Some numerical examples are solved and the mutual interaction between the temperature and displacement field is studied under the condition of structural vibration. The computational results demonstrate that the second-order asymptotic analysis finite-element algorithm is feasible and effective in simulating and predicting the dynamic thermo-mechanical behaviors of the composite materials with small periodic configurations in axisymmetric and spherical symmetric structures. This may provide a vital computational tool for analyzing composite material internal temperature distribution and structural deformation induced by the dynamic thermo-mechanical coupling response under strong aerothermodynamic environment. Second-order two-scale (SOTS) expansions for dynamic thermo-mechanical coupling problems in symmetric structure are obtained.SOTS finite element algorithm is proposed and unconditional stable implicit scheme is established.Anisotropic material is obtained by homogenization with enhanced strength and minor thermal expansion in circumferential direction.The mutual interaction and simultaneous vibration of the temperature and displacement field are simulated.A new computational tool is presented for analyzing thermo-mechanical response of composites under strong aerothermodynamic environment.

Phloem transcriptome signatures underpin the physiological differentiation of the pedicel, stalk and fruit of cucumber (Cucumis sativusL.)

Cucumber is one of the most important vegetables grown worldwide due to its important economic and nutritional value. The cucumber fruit consists morphologically of the undesirable stalk and the tasty fruit; however, physiological differentiation of these two parts and the underlying molecular basis remain largely unknown. Here we characterized the physiological differences among the pedicel, stalk and fruit, and compared the respective phloem transcriptomes using laser capture microdissection coupled with RNA sequencing (RNA-Seq). We found that the pedicel was characterized by minor cell expansion and a high concentration of stachyose, the stalk showed rapid cell expansion and high raffinose accumulation, and the fruit featured transition from cell division to cell expansion and high levels of monosaccharides. Analyses of transcriptome data indicated that cell wall- and calcium ion binding-related genes contributed to the cell expansion in the pedicel and stalk, whereas genes implicated in cell cycle and hormone actions regulated the transition from cell division to cell expansion in the fruit. Differential sugar distribution in these three phloem-connected tissues resulted from tissue-specific sugar metabolism and transport. Enrichment of transcription factors in the stalk and fruit may facilitate nutrient accumulation in these sink organs. As such, phloem-located gene expression partially orchestrated physiological differentiation of the pedicel, stalk and fruit in cucumber. In addition, we identified 432 cucumber-unique genes and five phloem markers guiding future functional studies.

Holocene glacier history of the Lago Argentino basin, Southern Patagonian Icefield

We present new geomorphic, stratigraphic, and chronologic data for Holocene glacier fluctuations in the Lago Argentino basin on the eastern side of the southern Patagonian Andes. Chronologic control is based on 14C and surface-exposure 10Be dating. After the Lateglacial maximum at 13,000 cal yrs BP, the large ice lobes that filled the eastern reaches of Lago Argentino retreated and separated into individual outlet glaciers; this recession was interrupted only by a stillstand or minor readvance at 12,200 cal yrs BP. The eight largest of these individual outlet glaciers are, from north to south: Upsala, Agassiz, Onelli, Spegazzini, Mayo, Ameghino, Perito Moreno, and Grande (formerly Frías). Holocene recession of Upsala Glacier exposed Brazo Cristina more than 10,115 ± 100 cal yrs BP, and reached inboard of the Holocene moraines in Agassiz Este Valley by 9205 ± 85 cal yrs BP; ice remained in an inboard position until 7730 ± 50 cal yrs BP. Several subsequent glacier readvances are well documented for the Upsala and Frías glaciers. The Upsala Glacier readvanced at least seven times, the first being a relatively minor expansion – documented only in stratigraphic sections – between 7730 ± 50 and 7210 ± 45 cal yrs BP. The most extensive Holocene advances of Upsala Glacier resulted in the deposition of the Pearson 1 moraines and related landforms, which are divided into three systems. The Pearson 1a advance occurred about 6000–5000 cal yrs BP and was followed by the slightly less-extensive Pearson 1b and 1c advances dated to 2500–2000 and 1500–1100 cal yrs BP, respectively. Subsequent advances of Upsala Glacier resulted in deposition of the Pearson 2 moraines and corresponding landforms, also separated into three systems, Pearson 2a, 2b, and 2c, constructed respectively at ∼700, >400, and <300 cal yrs BP to the early 20th century. Similar advances are also recorded by moraine systems in front of Grande Glacier and herein separated into the Frías 1 and Frías 2a, 2b, and 2c. The Onelli and Ameghino glacier valleys also preserve older Holocene moraines. In the Agassiz, Spegazzini, and Mayo valleys, ice of the late-Holocene advances appears to have overridden landforms equivalent in age to Pearson 1. Perito Moreno Glacier is an extreme case in which ice of historical (Pearson 2c) advances overrode all older Holocene moraines. Based on the distribution and number of moraines preserved, we infer that the response to climate differed among the Lago Argentino outlet glaciers during the Holocene. This led us to examine the effects of climatic and non-climatic factors on individual glaciers. As a consequence, we detected an important effect of the valley geometry (hypsometry) on the timing and magnitude of glacier response to climate change. These results indicate that caution is needed in correlating moraines among glacier forefields without firm morpho-stratigraphic and age control. Finally, we note important similarities and differences between the overall moraine chronology in the Lago Argentino basin and that in other areas of southern South America and elsewhere in the Southern Hemisphere.

The Synthesis of Ba‐ and Fe‐ Substituted CsAlSi2O6 Pollucites

Barium‐substituted CsAlSi2O6 pollucites, CsxBa(1−x)/2AlSi2O6, and barium‐ and iron‐substituted pollucites, CsxBa(1−x)/2AlxFe1−xSi2O6 and CsxBa1−xAlxFe1−xSi2O6 were synthesized with 1 ≥ x≥ 0.7 using a hydrothermal synthesis procedure. Rietveld analysis of X‐ray diffraction data confirmed the substitution of Ba for Cs and Fe for Al, respectively. The crystallographic analysis also describes the effects of three different types of pollucite substitutions on the pollucite unit cell: Ba2+ for Cs1+ cation results in little effect on cell dimensions, intermediate concentrations of Ba2+ and Fe3+ substitution result in net minor expansion due to Fe3+ addition, and large Ba and Fe substitutions result in overall framework contraction. Elemental analysis combined with microscopy further supports the phase purity of these new phases. These materials can be used to study the stability of CsAlSi2O6 as a durable ceramic waste form, which could accommodate with time Cs and its decay product, Ba. Furthermore, success in iron substitution for aluminum into the pollucite lattice predicts that redox charge compensation for Cs cation decay is possible.

Magnetocrystalline phase diagram of Gd: Probably a novel phase boundary

Single-crystalline gadolinium was examined employing both uniaxial and hydrostatic pressure with special attention to the spin-reorientation transition. A “temperature vs. pressure” magnetic phase diagram was established in both cases and a three-dimensional magnetic phase diagram “temperature vs. hcp crystalline lattice parameters a and c” was derived. An extrapolation of this phase diagram suggests a complete suppression of the spin-reorientation transition under minor expansion of the gadolinium crystalline lattice, constituting a novel phase boundary.