Systematic Extinction Research Articles

Language Death Perspectivation of Planned or Unplanned Language Death

The present paper is a conceptual paper which explores the innate nature of languages exploring how they are in constant flux. From their sociological birth to them being politically accepted, languages go through a plethora of changes. This paper explores concepts like high and low varieties of language e.g. Hindi in playgrounds and Hindi used to teach; the concept of prestige associated with a language, as well as concepts like elaborate and restricted code by Basil Bernstein. It explores the creole continuum and how they are connected to language death. Diglossic conditions may also lead to languages being used over another leading to language disuse. Certain linguistic groups, despite having a working language, assimilate themselves with a larger language due to many possible reasons (economic, political, geographical or anything else). This paper will take the discussion forward with how policy decisions can also lead to systematic extinction of certain languages due to the farsightedness of language planning. Paulo Friere (Friere, 1985) spoke about how local languages can be the backbones of language education. This paper explores the inability of state level language planning policies at incorporating local languages into the curriculum leading to eventual endangerment of the language over generations. This paper will also look at languages with shared script and how it might be the result of language imperialism over centuries. The content and opinions expressed are that of the authors and are not necessarily endorsed by/do not necessarily reflect the views of Azim Premji University.

Effect of acetochlor on the symbiotic relationship between microalgae and bacteria

In this study, two strains of symbiotic bacteria (SOB-1 and SOB-2) were isolated from Scenedesmus obliquus, and various algal-bacterial mutualistic systems were established under acetochlor (ACT) stress conditions. Following exposure to varying ACT concentrations from 2.0 to 25.0 μg/L, the capacity for co-cultured bacteria to degrade ACT was enhanced in 7 days by up to 226.9% (SOB-1) and 193.0% (SOB-2), compared with axenic algae, although bacteria exposed to higher ACT concentrations exacerbated algal metabolic stress, oxidative states, apoptosis and cellular lysis. ACT reduced carbohydrates in the phycosphere by up to 31.5%; compensatory nutrient plunder and structural damage by bacteria were the potential exploitation pathways determined based on the inhibition of bacterial infection using a glucanase inhibitor. The ACT-induced reduction in algal antimicrobial substances, including fatty acids and phenolics (by up to 58.1% and 56.6%, respectively), also facilitated bacterial exploitation of algae. ACT-dependent interspecific interaction coefficients between algae and bacteria generated from long-term symbiosis cultures implied that bacteria moved from mutualism (0 and 2.0 μg/L ACT) to exploitation (7.9 and 25.0 μg/L ACT). The population dynamic model under incremental ACT-concentration scenarios inferred that theoretical systematic extinction may occur in algal-bacterial systems earlier than in axenic algae. These outcomes provide interspecific insights into the distortion of algal-bacterial reciprocity due to the ecotoxicological effects of ACT.

M6O4(OH)4 of M = Sn, Pb: Single Crystal Growth and Crystal Structure Determinations Far Away from Routine

Single crystals of Sn6O4(OH)4 have been grown over a period of more than a decade in hermetically sealed flasks of various triorganotin(IV)-trihydrides in toluene/N,N-dimethylformamide and those of Pb6O4(OH)4 on a petri dish within some days from the reaction of Pb(ClO4)2 with Sr(OH)2·8H2O. High-resolution X-ray diffraction data of the tetragonally crystallizing compounds have been collected conventionally at 100 K. Crystal structure determinations have been performed in space groups P4/mnc and P4¯21c with different structure models because of a pretended specific systematic extinction condition. Its violation was routinely overseen because of the very low intensities of the respective reflections, an effect reinforced by crystal size. The non-existence of this systematic extinction was experimentally confirmed by studying the datasets in more detail, including the simulation of layer photographs. The importance of additional information obtained from dataset analysis tools and structure validation programs to assess the different structure models is demonstrated. Structures of both molecules are analyzed with respect to the molecules as a whole as well as to their constructive building units: two crystallographic different prototypes of {MO4} coordination polyhedra with a bent seesaw conformation, one μ3-OH- and one μ3-O- group, each trigonal-pyramidally coordinated.

Maximizing completeness in single-crystal high-pressure diffraction experiments: phase transitions in 2°AP.

Sufficiently high completeness of diffraction data is necessary to correctly determine the space group, observe solid-state structural transformations or investigate charge density distribution under pressure. Regrettably, experiments performed at high pressure in a diamond anvil cell (DAC) yield inherently incomplete datasets. The present work systematizes the combined influence of radiation wavelength, DAC opening angle and sample orientation in a DAC on the completeness of diffraction data collected in a single-crystal high-pressure (HP) experiment with the help of dedicated software. In particular, the impact of the sample orientation on the achievable data completeness is quantified and proved to be substantial. Graphical guides for estimating the most beneficial sample orientation depending on the sample Laue class and assuming a few commonly used experimental setups are proposed. The usefulness of these guides has been tested in the case of luminescent 1,3-diacetylpyrene, suspected to undergo transitions from the α phase (Pnma) to the γ phase (Pn21 a) and δ phase (P1121/a) under pressure. Effective sample orientation has ensured over 90% coverage even for the monoclinic system and enabled unrestrained structure refinements and access to complete systematic extinction patterns.

Limited role of spatial self-structuring in emergent trade-offs during pathogen evolution

Pathogen transmission and virulence are main evolutionary variables broadly assumed to be linked through trade-offs. In well-mixed populations, these trade-offs are often ascribed to physiological restrictions, while populations with spatial self-structuring might evolve emergent trade-offs. Here, we reexamine a spatially-explicit, SIR model of the latter kind proposed by Ballegooijen and Boerlijst with the aim of characterising the mechanisms causing the emergence of the trade-off and its structural robustness. Using invadability criteria, we establish the conditions under which an evolutionary feedback between transmission and virulence mediated by pattern formation can poise the system to a critical boundary separating a disordered state (without emergent trade-off) from a self-structured phase (where the trade-off emerges), and analytically calculate the functional shape of the boundary in a certain approximation. Beyond evolutionary parameters, the success of an invasion depends on the size and spatial structure of the invading and invaded populations. Spatial self-structuring is often destroyed when hosts are mobile, changing the evolutionary dynamics to those of a well-mixed population. In a metapopulation scenario, the systematic extinction of the pathogen in the disordered phase may counteract the disruptive effect of host mobility, favour pattern formation and therefore recover the emergent trade-off.

Crystal structure, phase transition and structural deformations in iron borate (Y0.95Bi0.05)Fe3(BO3)4 in the temperature range 90-500 K.

An accurate X-ray diffraction study of (Y0.95Bi0.05)Fe3(BO3)4 single crystals in the temperature range 90-500 K was performed on a laboratory diffractometer and used synchrotron radiation. It was established that the crystal undergoes a diffuse structural phase transition in the temperature range 350-380 K. The complexity of localization of such a transition over temperature was overcome by means of special analysis of systematic extinction reflections by symmetry. The transition temperature can be considered to be Tstr ≃ 370 K. The crystal has a trigonal structure in the space group P3121 at temperatures of 90-370 K, and it has a trigonal structure in the space group R32 at 375-500 K. There is one type of chain formed by the FeO6 octahedra along the c axis in the R32 phase. When going into the P3121 phase, two types of nonequivalent chains arise, in which Fe atoms are separated from the Y atoms by a different distance. Upon lowering the temperature from 500 to 90 K, a distortion of the Y(Bi)O6, FeO6, B(2,3)O3 coordination polyhedra is observed. The distances between atoms in helical Fe chains and Fe-O-Fe angles change non-uniformly. A sharp jump in the equivalent isotropic displacement parameters of O1 and O2 atoms within the Fe-Fe chains and fluctuations of the equivalent isotropic displacement parameters of B2 and B3 atoms were observed in the region of structural transition as well as noticeable elongation of O1, O2, B2, B3, Fe1, Fe2 atomic displacement ellipsoids. It was established that the helices of electron density formed by Fe, O1 and O2 atoms may be structural elements determining chirality, optical activity and multiferroicity of rare-earth iron borates. Compression and stretching of these helices account for the symmetry change and for the manifestation of a number of properties, whose geometry is controlled by an indirect exchange interaction between iron cations that compete with the thermal motion of atoms in the structure. Structural analysis detected these changes as variations of a number of structural characteristics in the c unit-cell direction, that is, the direction of the helices. Structural results for the local surrounding of the atoms in (Y0.95Bi0.05)Fe3(BO3)4 were confirmed by EXAFS and Mössbauer spectroscopies.

Directional surface enhanced Raman scattering on gold nano-gratings

Directional plasmon excitation and surface enhanced Raman scattering (SERS) emission were demonstrated for 1D and 2D gold nanostructure arrays deposited on a flat gold layer. The extinction spectrum of both arrays exhibits intense resonance bands that are redshifted when the incident angle is increased. Systematic extinction analysis of different grating periods revealed that this band can be assigned to a propagated surface plasmon of the flat gold surface that fulfills the Bragg condition of the arrays (Bragg mode). Directional SERS measurements demonstrated that the SERS intensity can be improved by one order of magnitude when the Bragg mode positions are matched with either the excitation or the Raman wavelengths. Hybridized numerical calculations with the finite element method and Fourier modal method also proved the presence of the Bragg mode plasmon and illustrated that the enhanced electric field of the Bragg mode is particularly localized on the nanostructures regardless of their size.

Evolution in the smallest valves (stomata) guides even the biggest trees.

The regal stature of the redwood sister-giants, Sequoia and Sequoiadendron, makes them internationally renowned icons of size and longevity. Yet an examination of the evolutionary history of the sequoiid clade (which includes the dawn redwood— Metasequoia) quickly dispels the impression that these trees are an immutable part of the landscape. Fossil data show that these species are relicts of a lineage that once extended North to the Arctic Circle and as far south as Australia ( Hill and Brodribb 1999, Ahuja and Neale 2002), and like many other basal lineages of the Cupressaceae, the three extant sequoiid genera have been subject to systematic extinction that has left only monotypic representatives alive today. Similar to other basal Cupressaceae, Sequoia and Sequoiadendron are confined to humid forest or fog belts, a habitat that appears to be very vulnerable to climate warming and associated drought ( Pounds et al. 1999). This is an important context because an extreme drought event is currently occurring across the entire range of both species, raising pertinent questions about how effectively these species are able to manage water stress. Of particular concern is whether this current drought represents a threat to the survival of trees. Answering such a question demands quantitative knowledge of what constitutes a damaging level of water stress in these species. A study by Ambrose et al. (2015) in this issue of Tree Physiology provides some answers to this critical question, while at the same time providing new insights into the surprisingly different ways these sister-species respond to water stress.

Dodecagonal quasicrystal in Mn-based quaternary alloys containing Cr, Ni and Si

A dodecagonal quasicrystal showing 12-fold symmetry forms in Mn-rich quaternary alloys containing 5.5 or 7.5 at.% Cr, 5.0 at.% Ni and 17.5 at.% Si. After annealing at 700 °C for 130 h, the quasicrystal precipitated in a matrix of β-Mn-type crystalline phase. The shape of the quasicrystal is needle-like having a length of several tens of micrometres. Electron diffraction as well as powder X-ray diffraction experiments has revealed the following characteristics of the quasicrystal: diffraction symmetry 12/mmm, the presence of systematic extinction for h1h2h2h1h5-type reflections with odd h5 index, and then five-dimensional space group P126/mmc. Indexing of the reflections indicated that the dimension of the common edge in the equilateral triangle–square tiling is 4.560 Å, and the periodicity is 4.626 Å along the 12-fold axis. This is the first example of the dodecagonal quasicrystal synthesized by ordinary metallurgical method in 3-d transition-metal alloys.

A modulation wave approach to the order hidden in disorder.

The usefulness of a modulation wave approach to understanding and interpreting the highly structured continuous diffuse intensity distributions characteristic of the reciprocal spaces of the very large family of inherently flexible materials which exhibit ordered 'disorder' is pointed out. It is shown that both longer range order and truly short-range order are simultaneously encoded in highly structured diffuse intensity distributions. The long-range ordered crystal chemical rules giving rise to such diffuse distributions are highlighted, along with the existence and usefulness of systematic extinction conditions in these types of structured diffuse distributions.

Increases in fire risk due to warmer summer temperatures and wildland urban interface changes do not necessarily lead to more fires

Forest fire frequency in Mediterranean countries is expected to increase with land cover and climate changes as temperatures rise and rainfall patterns are altered. Although the cause of many Mediterranean fires remains poorly defined, most fires are of anthropogenic origin and are located in the wildland urban interface (WUI), so fire ignition risk depends on both weather and land cover characteristics. The objectives of this study were to quantify the overall trends in forest fire risk in the WUI of the Alpes-Maritimes department in SE France over a period of almost 50 years (about 1960–2009) and relate these to changes in land cover and temperature changes. Land cover for two contrasting reference catchments (236 km2 and 289 km2, respectively) was mapped from available aerial photographs. Changes in fire risk over time were estimated using statistical relationships defined for each type of WUI, where isolated and scattered housing present a greater risk than dense and very dense housing. Summer monthly temperatures and spring and summer precipitation were quantified over the same temporal period as land cover. Finally, trends in fire frequency and burned area were analyzed over a shorter 37 year period (1973–2009) due to the lack of available fire data before 1973. Fire risk associated with WUI expansion increased by about 18%–80% over the 1960–2009 period (depending on the catchment). Similarly, mean summer minimum and maximum monthly temperatures increased by 1.8 °C and 1.4 °C, respectively, over the same period. Summer rainfall appears to decrease over time since about the 1970's but remains highly variable. Land cover and weather changes both suggest an overall increase in fire risk. However, the number of fires and burned area have decreased significantly since about 1990. This paradoxical result is due to a change in fire-fighting strategy which reinforced the systematic extinction of fires in their early stages. Technical support in the form of improved radio communication and helicopters contributed greatly to reducing fire frequency and burned area. Surveillance and legal reforms included the introduction of field patrols and restricted access to forests during high risk periods. Although this has proven highly successful in the short term, the risk of fuel load accumulation over time remains a risk which might contribute to the development of mega-fires in extreme climatic conditions in the future.

First description of Phanerozoic radiaxial fibrous dolomite

The petrographic analysis and crystallographic analysis of concretionary carbonate cements (“coal balls”) from Carboniferous paralic swamp deposits reveal the presence of (length fast) radiaxial fibrous dolomite (RFD), a fabric not previously reported from the Phanerozoic. This finding is of significance as earlier reports of Phanerozoic radiaxial fibrous carbonates are exclusively of calcite mineralogy. Dolomite concretions described here formed beneath marine transgressive intervals within palustrine coal seams. This is of significance as seawater was arguably the main source of Mg2+ ions for dolomite formation. Here, data from optical microscopy, cathodoluminescence, electron backscattered diffraction, X-ray diffraction and geochemical analyses are presented to characterize three paragenetic dolomite phases and one calcite phase in these concretions. The main focus is on the earliest diagenetic, non-stoichiometric (degree of order: 0.41–0.46) phase I, characterized by botryoidal dolomite constructed of fibres up to 110μm wide with a systematic undulatory extinction and converging crystal axes. Petrographic and crystallographic evidence clearly qualifies phase I dolomite as radiaxial fibrous. Conversely, fascicular optical fabrics were not found. Carbon-isotope ratios (δ13C) are depleted (between −11.8 and −22.1‰) as expected for carbonate precipitation from marine pore-fluids in organic-matter-rich, paralic sediment. Oxygen isotope (δ18O) ratios range between −1.3 and −6.0‰. The earliest diagenetic nature of these cements is documented by the presence of ubiquitous, non-compacted fossil plant remains encased in phase I dolomite as well as by the complex zoned luminescence patterns in the crystals and is supported by crystallographic and thermodynamic considerations. It is argued that organic matter, and specifically carboxyl groups, reduced thermodynamic barriers for dolomite formation and facilitated Mg/CaCO3 precipitation. The data shown here reveal a hitherto unknown level of complexity with respect to radiaxial fibrous carbonates and are of importance for those concerned with dolomite and carbonate petrography in general.

NEAR-INFRARED ADAPTIVE OPTICS IMAGING OF INFRARED LUMINOUS GALAXIES: THE BRIGHTEST CLUSTER MAGNITUDE-STAR FORMATION RATE RELATION

We have established a relation between the brightest super star cluster magnitude in a galaxy and the host star formation rate (SFR) for the first time in the near infrared (NIR). The data come from a statistical sample of ~ 40 luminous IR galaxies (LIRGs) and starbursts utilizing K-band adaptive optics imaging. While expanding the observed relation to longer wavelengths, less affected by extinction effects, it also pushes to higher SFRs. The relation we find, M_K ~ - 2.6 log SFR, is similar to that derived previously in the optical and at lower SFRs. It does not, however, fit the optical relation with a single optical to NIR color conversion, suggesting systematic extinction and/or age effects. While the relation is broadly consistent with a size-of-sample explanation, we argue physical reasons for the relation are likely as well. In particular, the scatter in the relation is smaller than expected from pure random sampling strongly suggesting physical constraints. We also derive a quantifiable relation tying together cluster-internal effects and host SFR properties to possibly explain the observed brightest SSC magnitude vs. SFR dependency.

On Brittain and Spotton’s <em>Memorandum</em>

On Brittain and Spotton's MemorandumMemorandum. Directed by Donald Brittain and John Spotton. 1967. Montreal, QC: National Film Board of Canada, 58 mins.About Memorandum Amos Vogel, in his book Film as Subversive Art, declared: With [Alain Resnais' 1955] Night and Fog, this is unquestionably the most sophisticated film yet made on the philosophical and moral problems posed by the concentration camp universe.1 Vogel praises what he calls a complex filmic structure, combining cinema verite and constant mingling of past and present.2Donald Brittain (1928-1989) was documentary filmmaker whose work frequently explored the lives of iconic (and usually controversial) personalities, from communist sympathizer Norman Bethune (Bethune, 1964) to Parti Quebecois founder and separatist Rene Levesque (The Champions trilogy, 1978-1986). His films critique how Canadians define themselves, and the dehumanizing effects of routine and bureaucracy, an issue central to Memorandum. His collaborator on the film was John Spotton (1927-1991), cinematographer, director, and editor at the National Film Board of Canada. Spotton's work on Wolf Koenig and Roman Kroitor's Lonely Boy (1962) helped popularize the cinema verite movement in the early 1960s.I first saw Memorandum in an undergraduate class on documentary cinema. At the core of Memorandum is what Brittain would later call the Canadian hook-the story of Bernard Laufer, Toronto glass cutter and Bergen Belsen survivor who returns to Germany in 1965 on tour of his old concentration camp. As Laufer's pilgrimage unfolds, the filmmakers show us images of postwar life in Germany and Austria. What becomes instantly clear is how quickly things seem to have reverted back to normal. Restaurateurs prepare for Oktoberfest while fresh grass grows over Dachau, and Belsen's barracks are now NATO firing range-what the film calls garden. Everything is green, everything is nice, remarks survivor. The older generation wants to change the subject, says German youth. The film, meanwhile, rejects this willful ignorance, this notion that the Holocaust is history and Hitler's campaign is in the past.Memorandum's indictment of Western routine and ordinariness underscores the notion that the atrocity was perpetuated by people simply doing their jobs. The systematic extinction of European Jewry, the film suggests, was carried out by ostensibly ordinary individuals-sane, God-fearing citizens who simply claimed to be following orders. Hannah Arendt (whose coverage of the Eichmann trial would inspire Brittain to pitch the Memorandum project to the National Film Board of Canada) famously dubbed this the banality of evil.3 Birkenau, camp that the film tells us once consumed 12,000 humans day, two and half million in two and half years [. . .] was not the work of mad men, but product of Western civilization. Memorandum dismisses any attempt to rationalize the Holocaust as singular act of insanity: the film maintains that once crime has been committed, it becomes for all time potentiality.Compared to the unfiltered brutality of Resnais' film, Memorandum's approach to the Holocaust is subdued and intentionally detached. Rather than attempting to explore the totality of the genocide, Memorandum offers images of modern, urban Berlin, city that fundamentally does not want to talk about the war. …

Magnetic symmetry in the Bilbao Crystallographic Server: a computer program to provide systematic absences of magnetic neutron diffraction

MAGNEXTis a new computer program available from the Bilbao Crystallographic Server (http://www.cryst.ehu.es) that provides symmetry-forced systematic absences or extinction rules of magnetic nonpolarized neutron diffraction. For any chosen Shubnikov magnetic space group, the program lists all systematic absences, and it can also be used to obtain the list of the magnetic space groups compatible with a particular set of observed systematic absences. Absences corresponding to specific ordering modes can be derived by introducing effective symmetry operations associated with them. Although systematic extinctions in neutron diffraction do not possess the strong symmetry-resolving power of those in nonmagnetic crystallography, they can be important for the determination of some magnetic structures. In addition,MAGNEXTprovides the symmetry-adapted form of the magnetic structure factor for different types of diffraction vectors, which can then be used to predict additional extinctions caused by some prevailing orientation of the atomic magnetic moments. This program, together with a database containing comprehensive general information on the symmetry operations and the Wyckoff positions of the 1651 magnetic space groups, is the starting point of a new section in the Bilbao Crystallographic Server devoted to magnetic symmetry and its applications.

The NDUFB6 subunit of the mitochondrial respiratory chain complex I is required for electron transfer activity: A proof of principle study on stable and controlled RNA interference in human cell lines

Molecular bases of inherited deficiencies of mitochondrial respiratory chain complex I are still unknown in a high proportion of patients. Among 45 subunits making up this large complex, more than half has unknown function(s). Understanding the function of these subunits would contribute to our knowledge on mitochondrial physiology but might also reveal that some of these subunits are not required for the catalytic activity of the complex. A direct consequence of this finding would be the reduction of the number of candidate genes to be sequenced in patients with decreased complex I activity. In this study, we tested two different methods to stably extinct complex I subunits in cultured cells. We first found that lentivirus-mediated shRNA expression frequently resulted in the unpredicted extinction of additional gene(s) beside targeted ones. This can be ascribed to uncontrolled genetic material insertions in the genome of the host cell. This approach thus appeared inappropriate to study unknown functions of a gene. Next, we found it possible to specifically extinct a CI subunit gene by direct insertion of a miR targeting CI subunits in a Flp site (HEK293 Flp-In cells). By using this strategy we unambiguously demonstrated that the NDUFB6 subunit is required for complex I activity, and defined conditions suitable to undertake a systematic and stable extinction of the different supernumerary subunits in human cells.

Polarization periodicity in theB1columnar phase determined by resonant x-ray scattering

We report structural results that evidence the polarization distribution of the blocks in the columnar phase of an achiral bent-core liquid crystal. The study was performed using resonant x-ray diffraction at the sulfur K edge on oriented samples aligned on substrates. The extra periodicity is revealed through the violation of the systematic extinction rule of the structural symmetry group along the experimentally accessible diffraction direction. Further data obtained from the polarization analysis of a resonant reflection give information concerning the transition mechanism between B(1) and B(2) phases.

Design of broadband QWIPs for operation above BLIP temperature

One of the key features of quantum well infrared photodetectors is the narrow absorption band. This inherently narrow spectral response has been proven to be an excellent asset to enhance the contrast in thermal images. Yet, some applications, as the infrared spectroscopy, require broadband detection. Several approaches have been used to get a broadband response with QWIPs. In particular, superlattices and digital graded barriers in the active layers have been proposed to get transitions between minibands in the first case and multiple transitions in the second case. A number of authors reported stacked and interlaced designs using regular QWIPs. In this article we focus on the interlaced approach. We show that conventional design approaches lead to a systematic extinction of longer wavelengths when the detector operates above BLIP temperature. We investigate both numerically and experimentally the underlying origins of this spectral change. This effect is attributed to an internal electric field redistribution in order to conserve the current flow through the active layer. Based on this study, we propose a specific design for broadband interlaced QWIP. This sample has been grown, processed and characterized. The experimental results present a quasi-independent spectral shape whatever the temperature or bias.

Symmetry analysis of extinction rules in diffuse-scattering experiments

Structured diffuse-scattering intensities, whether of compositional or of pure displacive origin, static or dynamic, contain important information about the symmetry of the individual compositional and/or displacive modes responsible for the observed intensities. However, the interpretation of the experimental data is very often impeded by the lack of a symmetry-based approach to the analysis of the structured diffuse-scattering distributions. Recently, we have demonstrated the existence of systematic phonon selection rules for diffuse scattering that depend on the symmetries of the mode and the scattering vector, and not on the specific structure. Here, we show that such symmetry analysis can be successfully extended and also applied to structure-dependent diffuse scattering associated with 'disordered' materials: the combination of theoretically determined, diffuse-scattering extinction conditions with the concept of non-characteristic orbits proves to be very useful in the interpretation of the observed diffuse-scattering extinctions. The utility of this approach is illustrated by the analysis of diffuse-scattering data from ThAsSe, FeOF and FeF(2). The essential part of the associated calculations are performed by the computer programs NEUTRON (systematic phonon extinction rules in inelastic scattering) and NONCHAR (non-characteristic orbits of space groups) that are available on the Bilbao crystallographic server (http://www.cryst.ehu.es).

Crystallization Behavior of Coordination Polymers. 2. Surface Micro-Morphology and Growth Mechanisms of [Cu(bpp)3Cl2]·2H2O by in Situ Atomic Force Microscopy

Crystal growth of the one-dimensional coordination polymer [Cu(1,3-bis(4-pyridyl)propane)3Cl2]·2H2O was investigated in aqueous solutions by in situ atomic force microscopy. Details about the growth mechanisms of the {001} form at low supersaturation were obtained. In particular, growth hillocks due to simple and complex dislocation sources were observed as the only active mechanism. The thinnest steps observed on {001} faces and delimiting growth hillocks were d002 layers, in accordance with the elementary growth layer expected from the systematic extinction conditions of space group I2/a and hence from Bravais−Friedel−Donnay−Harker rules and Hartman and Perdok periodic bond chains theory. This feature of the {001} faces suggests that small oligomeric species can be involved in the crystal growth processes. The effects of unknown impurities in the organic ligand upon the growth of crystals of the title compound were also studied.