Unique Reflections Research Articles

Neutron and XRD Single-Crystal Diffraction Study and Vibrational Properties of Whitlockite, the Natural Counterpart of Synthetic Tricalcium Phosphate

A crystal chemical investigation of a natural specimen of whitlockite, ideally Ca9Mg(PO4)6[PO3(OH)], from Palermo Mine (USA), was achieved by means of a combination of electron microprobe analysis (EMPA) in WDS mode, single-crystal neutron diffraction probe (NDP) and single-crystal X-ray diffraction (XRD), and Fourier transform infrared (FTIR) spectroscopy. The crystal-chemical characterization resulted in the empirical formula (Ca8.682Na0.274Sr0.045)Σ9.000(Ca0.034□0.996)Σ1.000(Mg0.533Fe2+0.342Mn2+0.062Al0.046)Σ0.983(P1.006O4)6[PO3(OH0.968F0.032)Σ1.000]. Crystal-structure refinement, in the space group R3c, converged to R1 = 7.12% using 3273 unique reflections from NDP data and to R1 = 2.43% using 2687 unique reflections from XRD data. Unit cell parameters from NDP are a = 10.357(3) Å, c = 37.095(15) Å and V = 3446(2) Å3, and from XRD, the parameters are a = 10.3685(4) Å, c = 37.1444(13) Å and V = 3458.2(3) Å3. NDP results allowed a deeper definition of the hydrogen-bond system and its relation with the structural unit [PO3(OH)]. The FTIR spectrum is very similar to that of synthetic tricalcium phosphate Ca3(PO4)2 and displays minor band shifts due to slightly different P-O bond lengths and to the presence of additional elements in the structure. A comparison between whitlockite, isotypic phases from the largest merrillite group, and its synthetic counterpart Ca3(PO4)2 is provided, based on the XRD/NDP and FTIR results.

Simulation of SAXS patterns from oriented lamellar structures and their elliptical trajectories

Small-angle X-ray Scattering (SAXS) patterns are useful for studying the organization of crystalline and amorphous regions that make up a semi-crystalline polymer and influence its properties. To understand how these patterns originate and evolve during deformation, three distinct SAXS patterns (2-point, 4-point ‘eyebrow’, and 4-point ‘butterfly’) were generated using simple microstructural models and compared in detail with experimental data from poly(ethylene-co-octene). As the patterns typically contain a single unique reflection, it is not possible to fully determine the structure from the patterns alone. Therefore, structural models with lamellar stacks were used to simulate SAXS patterns. When stack orientation (interlamellar shear) and chain slip act to rotate lamellae in the same sense, the result is an ‘eyebrow’ pattern. Opposite senses give a ‘butterfly’ pattern. Experimental patterns often have reflections where the peak position traces out an ellipse. Adding moderate amounts of rotational disorder to the models produces this effect without any elliptical correlations or deformed lattice in the material.

Thick-skinned tectonics of the Achankovil Shear Zone, southern India, inferred from new deep seismic reflection image: Constraints on the East African Orogen

The East Gondwana was formed by the assembly of continental fragments, namely India, Madagascar, Sri Lanka, and Antarctica, with the evolution of 2000 km long East African Orogen around 550 Ma. Lack of knowledge on the subsurface structure of the orogen led to a wide range of evolutionary models. The present study attempts to resolve various models’ ambiguity by presenting new results of the first deep seismic reflection study across the Achankovil Shear Zone, Southern Granulite Terrain, India that was evolved during the East African Orogen. The seismic study is also the first of its kind among the east Gondwana fragments. The Common reflection surface stack images of the present study reveal hitherto unknown details along with a unique south-dipping reflection fabric extending from the surface to upper mantle depth. We interpret this fabric is formed due to subduction-accretion of Madurai and Trivandrum blocks during the East African Orogen and represents a suture zone. Two deep-seated shear zones, the Achankovil and Tenmalai were also developed at both ends of collision fabric with strike-slip characteristics. Orogenic collapse and post-orogenic extension are inferred from the subhorizontal lower-crustal reflection fabric, which is interpreted as an equilibrated younger Moho. The present study provided an opportunity to understand the formation and exhumation of granulites, which act as a window on the inaccessible lower continental crust. Gravity modelling is performed along the seismic profile. Integration of present results with the existing geological and geophysical data provided basic constraints on the structure and tectonics of east Gondwana fragments and the East African Orogen.

Lateral Gradient Ambidextrous Optical Reflection in Self-Organized Left-Handed Chiral Nematic Cellulose Nanocrystals Films.

Artificial photonic materials displaying ordered reflected color patterns are desirable in the field of photonic technologies, however, it is challenging to realize. Here we present that self-assembly of cellulose nanocrystals (CNC) in a tilted cuvette leads to the formation of rainbow color CNC films. We show that the self-organized CNC films enable simultaneous reflection of left-handed circularly polarized (LCP) and right-handed circularly polarized (RCP) light with lateral gradient transmittance ratio (LCP/RCP: 8.7–0.9) and the maximum reflectance value up to ca. 72%. This unique ambidextrous optical reflection arises from left-handed chiral photonic architectures with lateral gradient photonic bandgaps and nematic-like defects at the film-substrate interface and between left-handed photonic bandgap layers acting as a half-wavelength retarder. We demonstrate that the tilted angle self-assembly method provides a feasible step toward color patterning of CNC-based photonic films capable of ambidextrous optical reflection.

Celleriite, ☐(Mn22+Al)Al6(Si6O18)(BO3)3(OH)3(OH), a new mineral species of the tourmaline supergroup

Abstract Celleriite, ☐(Mn22+Al)Al6(Si6O18)(BO3)3(OH)3(OH), is a new mineral of the tourmaline supergroup. It was discovered in the Rosina pegmatite, San Piero in Campo, Elba Island, Italy (holotype specimen), and in the Pikárec pegmatite, western Moravia, Czech Republic (co-type specimen). Celleriite in hand specimen is violet to gray-blue (holotype) and dark brownish-green (co-type) with a vitreous luster, conchoidal fracture, and white streak. Celleriite has a Mohs hardness of ~7 and a calculated density of 3.13 and 3.14 g/cm3 for holotype and its co-type, respectively. In plane-polarized light in thin section, celleriite is pleochroic (O = pale violet and E = light gray-blue in holotype; O = pale green and E = colorless in co-type) and uniaxial negative. Celleriite has trigonal symmetry: space group R3m, Z = 3, a = 15.9518(4) and 15.9332(3) Å, c = 7.1579(2) and 7.13086(15) Å, V = 1577.38(9) and 1567.76(6) Å3 for holotype and co-type, respectively (data from single-crystal X-ray diffraction). The crystal structure of the holotype specimen was refined to R1 = 2.89% using 1696 unique reflections collected with MoKα X-ray intensity data. Structural, chemical, and spectroscopic analyses resulted in the formulas: x ( ◻ 0.58 N a 0.42 ) Σ 1.00 Y ( M n 1.39 2 + F e 0.16 2 + M g 0.01 A l 1.14 F e 0.01 3 + L i 0.28 T i 0.01 ) Σ 3.00 Z A l 6 [ T ( S i 5.99 A l 0.01 ) Σ 6.00 O 18 ] ( B O 3 ) 3 ( O H ) 3 w [ ( O H ) 0.65 F 0.03 O 0.32 ] Σ 1.00 ( for holotype ) and x ( ◻ 0.51 N a 0.49 ) Σ 1.00 Y ( M n 0.90 2 + F e 0.50 2 + A l 1.36 F e 0.04 3 + L i 0.17 Zn 0.04 ) Σ 3.00 Z A l 6 [ T ( S i 5.75 B 0.25 ) Σ 6.00 O 18 ] ( B O 3 ) 3 ( O H ) 3 w [ ( O H ) 0.35 F 0.17 O 0.48 ] Σ 1.00 ( for co-type ) Celleriite is a hydroxy species belonging to the X-site vacant group of the tourmaline supergroup. The new mineral was approved by the Commission on New Minerals, Nomenclature and Classification of the International Mineralogical Association, proposal no. 2019-089. In the Rosina pegmatite, celleriite formed an overgrowth at the analogous pole of elbaite–fluorelbaite–rossmanite crystals during the latest stage of evolution of pegmatite cavities after an event of a pocket rupture. In the Pikárec pegmatite, celleriite occurs as an intermediate growth sector of elbaite, princivalleite, and fluor-elbaite.

Nevsun Resources Ltd. v. Araya

In Nevsun Resources Ltd. v. Araya, the Supreme Court of Canada declined to dismiss a series of customary international law claims brought by Eritrean refugees against a Canadian mining corporation for grave human rights abuses committed in Eritrea. In doing so, the Supreme Court opened the possibility of a novel front for transnational human rights litigation: common law tort claims based on customary international law. Under the doctrine of adoption, customary international law is directly incorporated into the Canadian common law. However, Canadian courts have not yet upheld a private right of action for violations of customary international law. Writing for a divided court (5–4), Justice Abella allowed the plaintiffs’ claims to proceed, finding that it is not “plain and obvious” that the plaintiffs’ customary international law claims are bound to fail under either Canada's burgeoning “transnational” or “foreign relations” law, or international law itself. In reaching this conclusion, she offered a unique and overdue reflection on the role of national courts in identifying, adopting, and developing custom. A larger majority of the court (7–2) also rejected outright the application of the act of state doctrine in Canada, tracking several common law systems in limiting the doctrine in favor of human rights litigants.

Calmodulin binds to Drosophila TRP with an unexpected mode

Drosophila TRP is a calcium-permeable cation channel essential for fly visual signal transduction. During phototransduction, Ca2+ mediates both positive and negative feedback regulation on TRP channel activity, possibly via binding to calmodulin (CaM). However, the molecular mechanism underlying Ca2+ modulated CaM/TRP interaction is poorly understood. Here, we discover an unexpected, Ca2+-dependent binding mode between CaM and TRP. The TRP tail contains two CaM binding sites (CBS1 and CBS2) separated by an ∼70-residue linker. CBS1 binds to the CaM N-lobe and CBS2 recognizes the CaM C-lobe. Structural studies reveal the lobe-specific binding of CaM to CBS1&2. Mutations introduced in both CBS1 and CBS2 eliminated CaM binding in full-length TRP, but surprisingly had no effect on the response to light under physiological conditions, suggesting alternative mechanisms governing Ca2+-mediated feedback on the channel activity. Finally, we discover that TRPC4, the closest mammalian paralog of Drosophila TRP, adopts a similar CaM binding mode.

The mineralogy of the historical Mochalin Log REE deposit, South Urals, Russia. Part III. Percleveite-(La), La2Si2O7, a new REE disilicate mineral

AbstractThe new mineral percleveite-(La) (IMA2019–037), ideally La2Si2O7, was found in polymineralic nodules of the Mochalin Log REE deposit, Chelyabinsk Oblast, South Urals, Russia. It is associated with allanite-(Ce), allanite-(La), bastnäsite-(Ce), bastnäsite-(La), ferriallanite-(Ce), ferriallanite-(La), ferriperbøeite-(Ce), ferriperbøeite-(La), fluorbritholite-(Ce), hydroxylbastnäsite-(Ce), perbøeite-(Ce), perbøeite-(La), törnebohmite-(Ce) and törnebohmite-(La). Percleveite-(La) occurs as isolated anhedral grains commonly up to 0.2 mm × 0.4 mm and very rarely up to 1 mm × 1 mm. The new mineral is transparent with greasy lustre. The mineral is very pale yellow to colourless in thin fragments to light yellow in aggregates. It is brittle, with imperfect {001} cleavage and an uneven fracture. Mohs’ hardness is ca. 6. Dcalc = 5.094 g cm–3. Under the microscope, percleveite-(La) is non-pleochroic, optically uniaxial (+), ω = 1.825(10) and ɛ = 1.835(10). The Raman spectrum is given. Chemical data (wt.%, electron-microprobe) are: La2O3 36.80, Ce2O3 31.22, Pr2O3 1.57, Nd2O3 2.96, SiO2 26.73, total 99.28. The empirical formula based on 7 O apfu is (La1.02Ce0.86Nd0.08Pr0.04)Σ2.00Si2.00O7. Percleveite-(La) is tetragonal, P41; the unit-cell parameters are: a = 6.8482(3), c = 24.8550(13) Å, V = 1165.64(11) Å3 and Z = 8. The strongest reflections in the powder X-ray diffraction pattern [d, Å(I)(hkl)] are: 4.194(18)(113), 3.564(16)(106), 3.349(16)(201,202), 3.157(100)(203,116,008), 3.043(22)(211), 2.934(39)(122), 2.893(29)(213) and 2.864(21)(117). The crystal structure of percleveite-(La) is solved from the single-crystal X-ray diffraction data [R = 0.0617 for 2831 unique reflections with I > 2σ(I)]. The new mineral is named as an analogue of percleveite-(Ce) with La predominance over the rare-earth elements.

Wumuite (KAl<sub>0.33</sub>W<sub>2.67</sub>O<sub>9</sub>) – a new mineral with an HTB-type structure from the Panzhihua–Xichang region in China

Abstract. Wumuite, ideally KAl0.33W2.67O9, is a new mineral species found in the Neoproterozoic Sinian light-weathered biotite–quartz monzonite in the southern part of the Panzhihua–Xichang region (Nanyang village: 26∘46′8.21′′ N, 101∘27′13.86′′ E), China. It is associated with quartz, orthoclase, albite, biotite, hornblende, kaolinite, ilmenite, goethite, hematite, zircon, zoisite, tourmaline, monazite-(Ce), allanite-(Ce), scheelite, tellurite, tewite, and an unidentified, potentially new mineral corresponding to WO3. Wumuite occurs as light green hexagonal tabular crystals, is up to 0.3 mm in diameter, and has a vitreous to adamantine luster and a white streak; i.e., it is transparent. The mineral is brittle with good cleavage parallel to {101¯0} and {0001}. It has a Mohs hardness of about 5–6 and a calculated density of 6.52 g cm−3. Electron microprobe analyses yielded the following (in wt % – average of 10 spot analyses of one sample): K2O 5.55, WO3 91.16, TeO2 0.59, and Al2O3 2.52, with a total of 99.82. The empirical formula for wumuite calculated on the basis of Oapfu=9 is K0.80(W2.68Al0.34Te0.03)∑3.05O9, ideally K(W2.67Al0.33)∑3O9 or KAl0.33W2.67O9. The strongest four diffraction lines [d Å (I) (hkl)] are 6.261(36)(010), 3.727(30)(001), 3.161(100)(020), and 2.413(40)(021). Wumuite is hexagonal, in space group P6/mmm, with a=7.2952(5) Å, c=3.7711(3) Å, V=173.81(2) Å3, and Z=1. The crystal structure was solved and refined to a reliability factor of R1[F2>4σ(F2)]=0.025 (wR2=0.072) based on 164 unique reflections (777 measured reflections, R(int)=0.011). Wumuite has a hexagonal tungsten bronze (HTB)-type structure. The layers of corner-sharing [(W,Al)O]6 octahedra, with the layers oriented normal to the short (3.7713 Å) c repeat and along with the W–O–W links, connect to form a hexagonal ring channel (tunnel). K is distributed in the hexagonal channel. An associated new mineral, tewite, which was discovered in the same area, also has a new tungsten bronze (TB)-type-related structure and has a genetic connection with wumuite in both back-scattered electron (BSE) images and synthetic experiments. The formation of wumuite is likely related to the nearby quartz-vein-type Au mineralization. The mineral was formed by a metasomatic reaction between W-rich hydrothermal fluids and the potassium feldspar in the monzonite.

ЗАОХОЧЕННЯ ЯК МЕХАНІЗМ ВПЛИВУ НА ПРОФЕСІЙНЕ САМОВДОСКОНАЛЕННЯ ВИКЛАДАЧІВ ІНОЗЕМНИХ МОВ КРАЇН ЄВРОПЕЙСЬКОГО СОЮЗУ

Recently, the importance of international cooperation in education, the use of the best practices of higher education institutions in the European Union, the development of pedagogical skills and professional activities to organize the process of foreign language teaching has been growing, so the issue of encouragement as a mechanism of influence on the professional development of foreign language teachers is relevant. It is noted that organization of higher education in the European Union has both much in common and in different. It is stated that the professional development of foreign language teachers in the European Union is a dynamic and continuous process that lasts throughout their activities. An important place is given to the motivation of teachers to self-improvement in order to achieve the highest level of professionalism. Teachers’ self-improvement allows them to deepen their professional competence by understanding the social and cultural dimensions of education, based on their own needs and requirements of society. It is determined that any culture finds its unique reflection in the language, as well as in the study of the cultural heritage of the people, which is enshrined in their language as a reflection of the spiritual world of humans and their culture. It is emphasized that an important role in the motivational process of encouragement as a mechanism for influencing the professional selfimprovement of foreign language teachers is played by the current system of encouragements in each European Union country. Encouragement systems reflect both the professional activity of an individual and the historical development of the country. Encouragement is a positive stimulating effect on the needs, interests, consciousness, will, behavior of foreign language teachers, as well as on the results of their work. Encouragement arouses the interest of the individual in obtaining certain social benefits and is used in cases of achieving results in own professional activities. Encouragement is used for successful performance of professional duties, important tasks, long-term work and is a mechanism of influence on the development of professional self-improvement. The analysis of scientific works on the problem under research shows that in the European Union countries national educational traditions are combined, that the motivational process for self-improvement depends on individual characteristics, age, pedagogical experience, scientific degree, position and is encouraged by the relevant stimulating moral (expression of gratitude, rewarding with certificate of appreciation, etc.) and material (rewarding with a gift, additional payments, financial awards, grants, etc.) systems of payment for work. The system of additional payments is non-uniform not only in the universities of different European Union countries, but also within a specific higher education institution. Teachers can be nominated for state awards for outstanding merit to the country. State awards are the highest form of recognition for high merit in the development of education, science, economy, culture. State awards are established exclusively by the laws of each country.

Participating in a community-based participatory research module: A reflective inquiry

This commentary piece, using a narrative inquiry frame, explores the experiences of five individuals who came together to participate in a community-based participatory research (CBPR) module. Owing to the short time frame of this accredited module, when the module was live, a particular focus was directed towards dialogical techniques to build trust and respect within the group and subsequently generate potential research questions. The inaugural experience of collaborating on a CBPR module stimulated unique feelings, reflections and learnings for participants, many of which took time to surface. This article aims to make sense of those experiences to support those wishing to engage in CBPR initiatives.

Mapping of Cotton Fields Within-Season Using Phenology-Based Metrics Derived from a Time Series of Landsat Imagery

A phenology-based crop type mapping approach was carried out to map cotton fields throughout the cotton-growing areas of eastern Australia. The workflow was implemented in the Google Earth Engine (GEE) platform, as it is time efficient and does not require processing in multiple platforms to complete the classification steps. A time series of Normalised Difference Vegetation Index (NDVI) imagery were generated from Landsat 8 Surface Reflectance Tier 1 (L8SR) and processed using Fourier transformation. This was used to produce the harmonised-NDVI (H-NDVI) from the original NDVI, and then phase and amplitude values were generated from the H-NDVI to visualise active cotton in the targeted fields. Random Forest (RF) models were built to classify cotton at early, mid and late growth stages to assess the ability of the model to classify cotton as the season progresses, with phase, amplitude and other individual bands as predictors. Results obtained from leave-one-season-out cross validation (LOSOCV) indicated that Overall Accuracy (OA), Kappa, Producer’s Accuracies (PA) and User’s Accuracy (UA), increased significantly when adding amplitude and phase as predictor variables to the model, than prediction using H-NDVI or raw bands only. Commission and omission errors were reduced significantly as the season progressed and more in-season imagery was available. The methodology proposed in this study can map cotton crops accurately based on the reconstruction of the unique cotton reflectance trajectory through time. This study confirms the importance of phenological metrics in improving in-season cotton fields mapping across eastern Australia. This model can be used in conjunction with other datasets to forecast yield based on the mapped crop type for improved decision making related to supply chain logistics and seasonal outlooks for production.

Assessing the nitrogen status of almond trees by visible-to-shortwave infrared reflectance spectroscopy of carbohydrates

Precise nitrogen (N) fertilization requires new indices of plants’ nutritional status. Non-structural carbohydrates (NSC) are the energetic currency of plants and can, thus, serve as a physiological indicator for their condition. Nevertheless, only a few records exist about NSC composition and allocation in crops, and their relationship with N uptake and the current methods to detect NSC compositions in plants are cumbersome and expensive, which limits their use. The current work aimed to associate the nutritional status of almond trees with the carbohydrate compositions in their roots, branches, and leaves by a high-throughput technique. We found that low N availability forces trees to allocate carbohydrates to their roots. High N availability, on the other hand, promoted above-ground vegetative growth, and minimized carbohydrate storage in the leaves. These observations implied that carbohydrate distribution could, indeed, serve as an indication of the nutritional status of the trees. To measure NSC content efficiently, we attempted to quantify soluble carbohydrates and starch in dried and powdered tissues by visible-to-shortwave infrared (VIS-NIR-SWIR; 350–2500 nm) reflectance spectroscopy, which is an inexpensive, safe, and non-destructive technique. We applied several multivariate statistical models based on the spectral datasets, including partial least squares-regression (PLS-R) and discriminant analysis (PLS-DA) as supervised registration and classification models. PLS-DA results of the N gradient in the roots and leaves showed an overall accuracy of 94% and 98%, respectively. PLS-R model performances of soluble carbohydrates and starch improved, in terms of the coefficient of determination (R2), if the leaf and root samples were integrated. Moreover, we found that the SWIR spectral region (1100–2500 nm) had unique reflectance features that revealed the carbohydrate composition and starch concentrations in the different plant tissues. The analyses also clustered the reflectance by tree part (root, branch, or leaf tissues) and N availability, forming a holistic model that can identify the nutritional status of trees. Conclusively, it is suggested that reflectance spectroscopy at the SWIR spectral region could guide precise fertilization by high-throughput identification of plants’ seasonal metabolism.

Hingganite-(Nd), Nd2□Be2Si2O8(OH)2, a new gadolinite-supergroup mineral from Zagi Mountain, Pakistan

ABSTRACT Hingganite-(Nd), ideally Nd2□Be2Si2O8(OH)2, is a new gadolinite group, gadolinite supergroup mineral discovered at Zagi Mountain, near Kafoor Dheri, about 4 km S of Warsak and 30 km NW of Peshawar, Khyber Pakhtunkhwa Province, Pakistan. The new mineral forms zones measuring up to 1 × 1 mm2 in loose prismatic crystals up to 0.7 cm long, where it is intergrown with hingganite-(Y). Other associated minerals include aegirine, microcline, fergusonite-(Y), and zircon. Hingganite-(Nd) is dark greenish-brown, transparent, has vitreous luster and a white streak. It is brittle and has a conchoidal fracture. No cleavage or parting are observed. Mohs hardness is 5½–6. Dcalc. = 4.690 g/cm3. Hingganite-(Nd) is non-pleochroic, optically biaxial (+), α = 1.746(5), β = 1.766(5), γ = 1.792(6) (589 nm). 2Vmeas. = 80(7)°; 2Vcalc. = 84°. Dispersion of optical axes was not observed. The average chemical composition of hingganite-(Nd) is as follows (wt.%; electron microprobe, BeO, B2O3, and Lu2O3 content measured by LA-ICP-MS; H2O calculated by stoichiometry): BeO 9.64, CaO 0.45, MnO 0.10, FeO 3.03, B2O3 0.42, Y2O3 8.75, La2O3 1.63, Ce2O3 12.89, Pr2O3 3.09, Nd2O3 16.90, Sm2O3 5.97, Eu2O3 1.08, Gd2O3 5.15, Tb2O3 0.50, Dy2O3 2.50, Ho2O3 0.33, Er2O3 0.84, Tm2O3 0.10, Yb2O3 0.44, Lu2O3 0.04, ThO2 0.13, SiO2 23.55, H2O 2.72, total 100.25. The empirical formula calculated on the basis of 2 Si apfu is (Nd0.513Ce0.401Y0.395Sm0.175Gd0.145Pr0.096Dy0.068La0.051Ca0.041Eu0.031Er0.022Tb0.014Yb0.011Ho0.009Tm0.003Th0.003Lu0.001)Σ1.979(□0.778Fe2+0.215Mn0.007)Σ1.000(Be1.967B0.062)Σ2.029Si2O8.46(OH)1.54. Hingganite-(Nd) is monoclinic, space group P21/c with a = 4.77193(15), b = 7.6422(2), c = 9.9299(2) Å, β = 89.851(2)°, V = 362.123(14) Å3, and Z = 2. The strongest lines of the powder X-ray diffraction pattern [d, Å (I, %) (hkl)] are: 6.105 (95) (011), 4.959 (56) (002), 4.773 (100) (100), 3.462 (58) (102), 3.122 , 3.028 (61) (013), 2.864 (87) (121), 2.573 (89) (113). The crystal structure of hingganite-(Nd) was refined from single-crystal X-ray diffraction data to R = 0.034 for 2007 unique reflections with I > 2σ(I). The new mineral is named as an analogue of hingganite-(Y), hingganite-(Yb), and hingganite-(Ce), but with Nd dominant among the rare earth elements.

Electing Economics: Election Law's Efficiency-Convergence Dilemma

We are facing a moment of unique reflection in American democracy. Data suggests that marginalized communities feel persistently ignored by political actors—on a bipartisan basis. The scale of wealth inequality is soaring to unprecedented heights. Domestic indifference to foreign interference in our elections has poisoned public confidence in the political process. Mass reckonings with institutionalized racism and police violence have rocked major cities, facing deep and violent resistance from the President and the federal government. A global pandemic disproportionately devastated Black and Brown communities, and the federal government’s response prioritized economic liberty over health and safety. Americans are reconsidering the nature of our relationship to the federal government, and the pressure for reform may now exceed any moment since the New Deal. In this setting, Iowa’s dramatic failure to efficiently administer the Democratic Presidential Caucus hardly seems worthy of a footnote in the history of 2020. Yet, at the time, it became a national story. Iowa’s failure to administer an efficient election was new—but election law’s marriage to economic efficiency is much older. Understanding the depth of efficiency’s roots in the law of democracy requires turning back to that same New Deal era. The conflict between the American Legal Realists and the laissez faire Lochnerism of the Supreme Court laid the groundwork for efficiency’s lasting role in law—and for the century of criticism that sprung up to contest it. Efficiency—and specifically, the conceptions of efficiency proffered by Chicago School Law and Economics and Virginia School Public Choice Theory—emerged victorious from those contests. But, we are facing a moment of unique reflection, and in such a moment, an opportunity arises. By looking back through efficiency’s rise, we can chart a course forward. This article offers a framework with which to do so: the efficiency-convergence dilemma. Part I builds the efficiency-convergence, outlining the intellectual history of efficiency’s role in election law. Part II builds the dilemma, highlighting critical legal theory and heterodox economics traditions that contour the normative concerns with the efficiency-convergence. Part III presents the framework. I develop a typology of efficiency arguments within election law, derived from novel primary source analysis of the legislative history for the Voting Rights Act and the National Voter Registration Act, along with case law and scholarship across election law. I theorize that this typology demonstrates an efficiency-convergence dilemma, functioning to institutionalize racial subordination as a neutral principle undergirding legal thought in the law of democracy. I offer a series of critiques for this efficiency-convergence, built from the critical theories discussed. Finally, Part IV offers two normative implications of the efficiency convergence. The first is to look outside the law, developing an operationalized definition of equity based on similar research in public health and public policy. The second is to highlight election law scholarship that bucks the efficiency convergence, charting a path forward. I present one such path: reimagining the right to vote as a constructive right implemented through constitutional conventions and norms and protected as an instrumental right.

WINGLESS GRIFFINS AMONG PAPYRUS PLANTS FROM NEOPALATIAL KNOSSOS? A RECONSTRUCTION PROPOSAL OF THE SEAL IMPRESSION CMS II8, 321

This paper offers a new interpretation of the motifs preserved on the fragmentary Late Minoan (LM) I seal impression from Knossos CMS II8, 321, proposing a reconstruction of the original scene as two couchant overlapping griffins without wings among papyrus plants. If correct, the combination of all these elements is quite exceptional, since this scene would provide a unique reflection in glyptic art of the famous Throne Room decoration of Knossos, with its imposing wingless griffins immersed in a lush landscape of papyrus-reeds. Although a well-known ivory plaque from Mycenae displays a similar composition with a single, ‘classical’, winged griffin, no seal image seems to show also the wingless beast and the overlapping pose of two couchant griffins. The present investigation explores several parallels not only for this rare, yet well-attested, compositional scheme in Aegean art, but also for the figure of the wingless griffin. Both will be found in the Pylian palace decorative programme, which offers further griffins without wings – even in glyptic art – a meaningful parallel, since the interconnections between the Palace of Nestor and the Palace of Minos provide some of the most intriguing material in the study of Aegean imagery.

Polymorphs of VO(PO3)2: synthesis and crystal structure refinement revisited

Abstract The monoclinic α-polymorph of (VIVO)(PO3)2 is obtained reproducibly by reaction of V2O5 and H3PO4 (85%) (Au crucible, 380 °C, 4 d). Its crystal structure was refined from X-ray single-crystal data [C2/c, Z = 4, a = 15.1038(7) Å, b = 4.193(2) Å, c = 9.573(9) Å, β = 126.45(3), R 1 = 0.052, wR 2 = 0.189 for 976 unique reflections with F o > 4σ(F o ), 48 variables]. A single-phase powder of the β-polymorph is obtained by the reaction of V2O5, H3PO4 (85%) and oxalic acid, evaporating the mixture, and subsequent annealing (porcelain crucible, 800 °C in air, 2 d). Single crystals of β-(VIVO)(PO3)2 were grown in a sealed silica ampoule with chlorine as mineralizer. The crystal structure of the orthorhombic (pseudo-tetragonal) β-polymorph was refined from X-ray single-crystal data [pseudo-merohedral twin, Fdd2, Z = 8, a = 15.536(2) Å, b = 15.586(2) Å, c = 4.2611(5) Å, R 1 = 0.032, wR 2 = 0.068 for 1072 unique reflections with F o > 4σ(F o ), 50 variables]. Earlier reports on a tetragonal polymorph with unusual geometric structure of the [(V≡O)O5] polyhedron are corrected.

Crystal-chemistry of sulfates from the Apuan Alps, Tuscany, Italy. VIII. New data on khademite, Al(SO4)F(H2O)5

AbstractKhademite, ideally Al(SO4)F(H2O)5, from the Monte Arsiccio mine, Apuan Alps, Tuscany, Italy, has been characterised through quantitative electron microprobe analysis, micro-Raman spectroscopy and single-crystal X-ray diffraction. Khademite occurs as colourless to whitish tabular crystals, up to 5 mm. Electron microprobe analysis (in wt.%, average of 20 spot analyses) gave: SO3 35.43, Al2O3 21.27, F 6.92, H2Ocalc 39.73, sum 103.35, –O = F 2.92, total 100.43. On the basis of 10 anions per formula unit, assuming the occurrence of 5 H2O groups and 1 (F+OH) atom per formula unit, its chemical formula can be written as Al0.96S1.02O4[F0.84(OH)0.16]Σ1.00⋅5H2O. The Raman spectrum of khademite is characterised by the occurrence of vibrational modes of SO4 groups and by broad and strong bands due to the O–H stretching modes. Khademite is orthorhombic, space group Pcab, with unit-cell parameters a = 11.1713(2), b = 13.0432(3), c = 10.8815(2) Å, V = 1585.54(5) Å3 and Z = 8. The crystal structure refinement converged to R1 = 0.0293 on the basis of 2359 unique reflections with Fo > 4σ(Fo) and 152 refined parameters. The crystal structure of khademite is characterised by the alternation, along b, of two distinct kinds of {010} layers, one formed by [001] rows of isolated Al-centred octahedra, connected to each other through H bonds, and the other showing isolated SO4 groups. Along b, oxygen atoms belonging to SO4 groups act as acceptor of H bonds from H2O groups coordinating Al atoms. The new data improved the description of the H bonds in khademite and led us to discuss about the possible existence of its (OH)-analogue, rostite. In addition, Raman spectroscopic data were collected on the same crystal used for the crystal-chemical characterisation, allowing a comparison with previous results.

Real Estate and Alternative Asset Allocations of U.S. Firms' Defined Benefit Pension Plans

This study examines the role of real estate and alternative assets in the investment portfolio of defined benefit (DB) pension plans offered by U.S. firms for the period 2002 to 201'3 These plans provide a unique reflection of the confluence of regulatory, accounting, and economic changes that have recently taken plance. Results indicate a quarter of our sample plans invest in real estate while more than half invest in alternative assets. Logistic and panel data regression analyses generally indicate that pension plan size, contribution levels, and funding status are significant in explaining the likelihood of and the variance in the allocation of plan assets to real estate and alternative investments.

Tancaite-(Ce), ideally FeCe(MoO<sub>4</sub>)<sub>3</sub> ● 3H<sub>2</sub>O: description and average crystal structure

Abstract. Tancaite-(Ce), ideally FeCe(MoO4)3⚫3H2O, is a new mineral occurring within cavities in the quartz veins which cut the granite at Su Seinargiu, Sarroch (CA), Sardinia, Italy. It is a secondary mineral formed in the oxidation zone of a sulfide ore vein. Associated minerals are quartz, muscovite, molybdenite, pyrite, and a mendozavilite-like phase. Tancaite-(Ce) is red or pale brown in colour, with a vitreous to adamantine lustre. Electron microprobe analyses give (wt %) SiO2 0.34, CaO 0.09, Fe2O3 11.29, SrO 0.02, La2O3 5.04, Ce2O3 10.35, Pr2O3 1.07, Nd2O3 3.66, Sm2O3 0.19, ThO2 2.58, UO2 0.17, MoO3 58.62, and H2O (calculated) 7.43, with a sum of 100.85, from which the empirical formula is calculated. The empirical formula Fe1.033+(Ce0.46La0.23Nd0.16Pr0.05Sm0.01U0.01Th0.07)Σ=0.99(Mo2.96Si0.04)Σ=3.00O12⚫3H2O can be simplified as Fe3+(REE)(MoO4)3⚫3H2O and idealized as FeCe(MoO4)3⚫3H2O. The presence of H2O was confirmed by micro-Raman spectrometry (stretching and bending vibrations of O–H). The calculated density is 3.834 g cm−3. The X-ray diffraction pattern of tancaite-(Ce) is characterized by a set of strong reflections, which point to a cubic subcell with a=6.870(1) Å and space group Pm3¯m, plus a set of superstructure reflections. Tancaite-(Ce) displays a new structure type not previously reported in natural and synthetic molybdates. By considering only the strong reflections, it was possible to solve and refine its average structure (R1=0.038 for 192 unique reflections with I>2σ(I)). The crystal structure consists of FeO6 octahedra centred at the origin of the cubic subcell and linked together through MoO4 tetrahedra by corner sharing. The Mo-centred tetrahedra are statistically distributed in four symmetry-related positions, with one-fourth occupancy. In the centre of the cubic unit cell the REE cations exhibit a 6+3 coordination, bonding six oxygen atoms and three H2O molecules, each of them being disorderly distributed in four symmetry-related positions. One of the possible supercells, with a 48-fold volume with respect to the primitive cubic small subcell, corresponded to a rhombohedral lattice, with a≈19.43 and c≈47.60 Å in the hexagonal setting. Several unsuccessful trials were performed to solve the real crystal structure of tancaite, by indexing the additional superstructure reflections and using their intensities to refine an ordered structural model. The new mineral has been approved by the IMA CNMNC (no. 2009-097). The name comes from Giuseppe Tanca, an Italian amateur mineralogist, who discovered the mineral and gave it to us for studying.