Quantitative plane-resolved crystal growth and dissolution kinetics by coupling in situ optical microscopy and diffusion models : the case of salicylic acid in aqueous solution

The growth and dissolution kinetics of salicylic acid crystals are investigated in situ by focusing on individual microscale crystals. From a combination of optical microscopy and finite element method (FEM) modeling, it was possible to obtain a detailed quantitative picture of dissolution and growth dynamics for individual crystal faces. The approach uses real-time in situ growth and dissolution data (crystal size and shape as a function of time) to parametrize a FEM model incorporating surface kinetics and bulk to surface diffusion, from which concentration distributions and fluxes are obtained directly. It was found that the (001) face showed strong mass transport (diffusion) controlled behavior with an average surface concentration close to the solubility value during growth and dissolution over a wide range of bulk saturation levels. The (1̅10) and (110) faces exhibited mixed mass transport/surface controlled behavior, but with a strong diffusive component. As crystals became relatively large, they tended to exhibit peculiar hollow structures in the end (001) face, observed by interferometry and optical microscopy. Such features have been reported in a number of crystals, but there has not been a satisfactory explanation for their origin. The mass transport simulations indicate that there is a large difference in flux across the crystal surface, with high values at the edge of the (001) face compared to the center, and this flux has to be redistributed across the (001) surface. As the crystal grows, the redistribution process evidently can not be maintained so that the edges grow at the expense of the center, ultimately creating high index internal structures. At later times, we postulate that these high energy faces, starved of material from solution, dissolve and the extra flux of salicylic acid causes the voids to close

Bedbugs evolved before their bat hosts and did not co-speciate with ancient humans

All 100+ bedbug species (Cimicidae) are obligate blood-sucking parasites [1, 2]. In general, blood sucking (hematophagy) is thought to have evolved in generalist feeders adventitiously taking blood meals [3, 4], but those cimicid taxa currently considered ancestral are putative host specialists [1, 5]. Bats are believed to be the ancestral hosts of cimicids [1], but a cimicid fossil [6] predates the oldest known bat fossil [7] by >30 million years (Ma). The bedbugs that parasitize humans [1, 8] are host generalists, so their evolution from specialist ancestors is incompatible with the "resource efficiency" hypothesis and only partially consistent with the "oscillation" hypothesis [9-16]. Because quantifying host shift frequencies of hematophagous specialists and generalists may help to predict host associations when vertebrate ranges expand by climate change [17], livestock, and pet trade in general and because of the previously proposed role of human pre-history in parasite speciation [18-20], we constructed a fossil-dated, molecular phylogeny of the Cimicidae. This phylogeny places ancestral Cimicidae to 115 mya as hematophagous specialists with lineages that later frequently populated bat and bird lineages. We also found that the clades, including the two major current urban pests, Cimex lectularius and C. hemipterus, separated 47 mya, rejecting the notion that the evolutionary trajectories of Homo caused their divergence [18-21]

Paraxial WKB Method Applied to the Lower Hybrid Wave Propagation

The paraxial WKB (pWKB) approximation, also called beam tracing method, has been employed in order to study the propagation of lower hybrid (LH) waves in a tokamak plasma. Analogous to the well-know ray tracing method, this approach reduces Maxwell's equations to a set of ordinary differential equations, while, in addition, retains the effects of the finite beam cross-section, and, thus, the effects of diffraction. A new code, LHBEAM (Lower Hybrid BEAM tracing), is presented, which solves the pWKB equations in tokamak geometry for arbitrary launching conditions and for analytic and experimental plasma equilibria. In addition, LHBEAM includes linear electron Landau damping for the evaluation of the absorbed power density and the reconstruction of the wave electric field in both the physical and Fourier space. Illustrative LHBEAM calculations are presented along with a comparison with the ray tracing code GENRAY and the full wave solver TORIC-LH

Carbon dioxide fluxes increase from day to night across European streams

Globally, inland waters emit over 2 Pg of carbon per year as carbon dioxide, of which the majority originates from streams and rivers. Despite the global significance of fluvial carbon dioxide emissions, little is known about their diel dynamics. Here we present a large-scale assessment of day- and night-time carbon dioxide fluxes at the water-air interface across 34 European streams. We directly measured fluxes four times between October 2016 and July 2017 using drifting chambers. Median fluxes are 1.4 and 2.1 mmol m−2 h−1 at midday and midnight, respectively, with night fluxes exceeding those during the day by 39%. We attribute diel carbon dioxide flux variability mainly to changes in the water partial pressure of carbon dioxide. However, no consistent drivers could be identified across sites. Our findings highlight widespread day-night changes in fluvial carbon dioxide fluxes and suggest that the time of day greatly influences measured carbon dioxide fluxes across European streams

A new Scirtetellus species from the Karakoram Mts., Pakistan (Heteroptera: Miridae)

Scirtetellus petrovi sp. n. (Heteroptera: Miridae) is described from the material collected in the Karakoram Mts., Pakistan, during the Bulgarian alpine expedition to Broad Peak in 2001.</jats:p

Bulgarian Vocative within HPSG framework

this paper, is not a language-specific one, in spite of the fact that most of the languages have their own repository for marking the role of the addressee in communicative utterances. In our opinion this linguistic phenomenon needs its adequate treatment because of two main reasons: 1. The vocative is supposed to be present on two levels: syntax and pragmatics. Therefore it needs more elaborate interpretation on the interface side, which, in HPSG, is more developed for morphology /syntax and syntax/semantics than syntax/pragmatics; 2. It will be useful for HPSG-oriented implementations, especially treebanks and dialogue systems. The paper is structured as follows: in the next section the status of the vocative in Bulgarian is discussed. In section 3 we propose our ideas on a unified treatment of vocatives. In section 4 the HPSG model is given. Section 5 outlines the conclusions and future work. 2 The Status of the Vocative in Bulgarian Vocatives are assumed to be restricted to the second person usage only. Usually they subsume the following two subtypes: calls (hey you) and addresses (Madam) [Levinson 1987, p. 71]. Bulgarian vocative role is usually treated within the opposition: vocative form (a remnant of the case paradigm) vs. base nominative form, i.e. with respect to the presence or loss of the special vocative inflections. Hence, The work reported here is done within the BulTreeBank project. The project is funded by the Volkswagen Stiftung, Federal Republic of Germany under the Programme &quot;Cooperation with Natural and Engineering Scientists in Central and Eastern Europe&quot; contract I/76 887. The authors wish to thank the Seminar fur Sprachwissenschaft of the Eberhard-Karls-Universitat, Tubingen, for hosting the writing of this paper, and the Internationales Zentr..

Bulgarian vocative in HPSG

Crosslinguistically vocatives are an underexplored linguistic phenomenon and in different languages they can be highly idiosyncratic and complex (Levinson, 1987, p.71). Therefore, the problem, which is discussed in this paper, is not a language-specific one, in spite of the fact that most of the languages have their own repositories for marking the role of the addressee in the communicative utterances. In our opinion this linguistic phenomenon needs its adequate treatment in HPSG because of three main reasons: &#x0D; &#x0D; The vocative is supposed to be present on two levels: syntax and pragmatics. Therefore it needs more elaborate interpretation on the interface side, which, in HPSG, is more developed for morphology/syntax and syntax/semantics than syntax/pragmatics. Note that a challenge for the theory is the semantic weight of the vocatives with respect to the head sentence. &#x0D; It will be useful for HPSG-oriented implementations, especially treebanks and dialogue systems. &#x0D; On prosodic grounds the vocatives are often viewed as being 'side or extended parts' of the sentence and therefore - very close to the parenthetical constructions. From our point of view, both phenomena are pragmatic and hence, the treatment of vocative, presented here, could be generalized to cover other phenomena of pragmatic nature. &#x0D; &#x0D; In our work the vocatives are viewed through the possibility of the integration/separation of their pragmatic, syntactic and semantic properties.</jats:p

A Hybrid System for MorphoSyntactic Disambiguation in Bulgarian

Introduction The interest in MorphoSyntactic Disambiguation Problem (MSDP) is supported by the hope that it is decidable with a high percentage of certainty without deep syntactic analysis to be involved. Our work is an attempt to solve this problem for Bulgarian using a hybrid system comprising Simple Recurrent Neural Network (SRN) component based on (Vlasseva 1999) and a rule-based component in order to disambiguate the cases for which there are rules ensuring 100% correct results. In our case the SRN component includes four layers of neurons: input, hidden, output and context. The input layer receives an encoding of the (possibly ambiguous) morphosyntactic features of the words in the sentences and the output layer represents the predicted by the net true features. In general, a disambiguation problem is to attach the right category to a textual element from a set of possible categories for this element. In the case of MorphoSyntactic disambiguation we have to choose the right mo