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Brancelj (2021) studies changes in the species composition of rotifers, cladocerans and copepods due to fish stocking in Slovenian lakes located on the limestone bedrock. During the observational period (1991-2012), large-bodied copepods and cladocerans were eliminated by fish leading to proliferation of small-bodied zooplankton along with benthic species, associated with algal mats. Using long lists of well-identified rotifer species from the lake sub-habitats, the authors state that species richness was lower in pelagic waters than in the region with aquatic vegetation. Based on historical data of about 17 years on zooplankton and chosen physico-chemical parameters, including nutrient concentrations and Chl I a i levels from 68 Danish lakes, the authors observed that when the lake pH was acid (< 6.0) calanoids were dominant in the copepod zooplankton community. [Extracted from the article]

A new method to determine the dewpoint pressure of a retrograde condensate from a fast, non-equilibrium measurement performed in a microfluidic optical cell is presented. The inflection point of the optical transmission recorded during depressurization agrees well with the dewpoint pressure of the sample, determined by conventional laboratory techniques. With this new technique, a measurement can be performed in less than 5 min and requires far less than a milliliter of the sample. Benchmarking of this technique is presented using four retrograde condensate samples, which were created in the laboratory using multi-component compositions that are based on oilfield samples. Each sample was characterized at three different temperatures, and their maximum relative liquid volumes (maximum liquid volume/total system volume at the dewpoint pressure) ranged from 1.3% to 13.5% for these temperatures. The dewpoint pressure measured by this technique differs by no more than 100 psi from that measured in a conventional laboratory for samples of a richness of 4% or higher, while leaner samples display a difference of ∼200 psi. [ABSTRACT FROM AUTHOR]

Presents an atomic force microscopic (AFM) observation of the surface morphology of thin films of indium gallium arsenic/indium phosphide. Experimental details; Results and discussion.

Presents a method for ultraclean radioactive marking. Details on the experiment; Results of the study; Simulated application of the method.

It is demonstrated that the growth direction of InP nanowires grown on (001)-oriented silicon substrate strongly depends on the diameter of the gold catalyst droplets. Small droplets with diameter less than about 15 nm lead to the formation of nanowires leaning on the {111} planes of the zinc blende InP seeds formed in the early stages of growth. Larger droplets lead to the formation of twins in the InP seeds and to the formation of nanowires leaning on the {111} planes of these twinned InP variants, inducing growth directions corresponding to the <115> directions of the silicon substrate. [ABSTRACT FROM AUTHOR]

The parthenogenetic female of a new anomopod crustacean, Notothrix halsei gen. n. et sp. n., is described from Lake Angove and found in five other sites in SW Australia. Although macrotrichid-like at first glance, a detailed morphological study including thoracic appendages revealed a set of primitive characters and similarities with primitive families, in particular with the Eurycercidae and Acantholeberidae. Ancestral traits of Notothrix gen. n. comprise: (i) a single large head pore; (ii) second maxilla; (iii) incomplete dorsal merger of valves; (iv) second antenna with a three- and a four-segmented branch; (v) six trunk limbs; (vi) two setae on a sixth endite in the first limb, vs. complete row of posterior setae on the second limb; (vii) large number of setae on exopodites III–V; (viii) well-developed gnathobase V; and (ix) massive postabdomen with wide, telson-like terminus between end-claws that show complex spinulation but no basal spine. Analysis of the complete 18S (SSU) rRNA gene sequence including taxa from all but four anomopod families and using Ctenopoda as an outgroup, confirms our separation of the new taxon, the Nototrichidae fam. n. Although different alignments resulted in different trees, the analyses confirm an isolated position of Notothrix, which has the shortest SSU rRNA gene length known for anomopods. However, the phylogenies derived from a comparison of 18S rRNA gene sequences between families of the order Anomopoda, does not resolve the descent of the various family groups. [ABSTRACT FROM AUTHOR]

The article reports that it is highly desirable to take advantage of GaAs wafers to develop semiconductor laser or optoelectronics devices working in wavelength range. Recently, the epitaxy of low bandgap nitride-based materials, such as GaAsN/GaAs and InGaAsN/GaAs, has received considerable attention as an alternative structure to InGaAsP/InP because of the large reduction of the bandgap with nitrogen incorporation. However, the incorporation behaviour and the properties of boron in GaAs or boron in InGaAs are not well known.

The article reports that the understanding and the control of thin film growth has been a slow process because little is known about chemical reactions and reaction kinetics parameters during the decomposition of metalorganic precursors. During the deposition process by metalorganic vapour phase epitaxy, the film surface plays a major role in the growth as the addition of new reactants can significantly modify the growth chemistries. For diluted-nitride materials the low nitrogen content x of the film is related to several factors, such as its low solubility, the kinetics of source decomposition and competitive adsorption of As. For instance, the N incorporation efficiency could be improved by using growth conditions far from thermodynamic equilibrium, such as low substrate temperature, high gas-phase supersaturation or high growth rate.

We tested the reciprocal effects of water conditioned by exudates of Aeolosoma sp. (Aphanoneura, Oligochaeta) and fish (Skiffia lermae: Goodeidae) and by the presence of Aeolosoma sp. on the population dynamics of four species of anomopod cladocerans (C. cornuta, C. dubia, S. serrulatus and S. vetulus) at 25 °C for 26 days using Chlorella vulgaris (1 × 106 cells ml-1) as a basic food for all. We found that, regardless of treatment, C. cornuta and C. dubia had a long initial phase of slow growth, followed by a rapid increase after the second week and that, regardless of treatment, C. dubia had a higher rate of population increase per day than C. cornuta. S. vetulus had a longer lag phase than S. serrulatus. Fish-conditioned water resulted in growth inhibition in S. serrulatus, but had no effect on S. vetulus, while Aeolosoma-conditioned water inhibited growth of S. vetulus but not that of S. serrulatus. Our results suggest a scale of responses of cladocerans to exposure to fish- and worm-conditioned water and to the presence of worms, ranging from a mild stimulation to no effects to inhibited growth. Kairomone-effects on body size of C. cornuta were not significant, but beak length was strongly influenced, and more by fish than by worm kairomones. In S. vetulus, differences in size were not significant. However, individuals grown in the presence of worms had higher biomass while those grown in the presence of fish and worm kairomones showed a decreased weight. Effects of worm exudates and of their live biomass on cladocerans were thus opposite in Simocephalus. In Ceriodaphnia dubia, in contrast, they were additive. Aeolosoma was depressed by all four cladocerans, although worms tried to penetrate the valves of the cladocerans to feed on the tissue inside. In doing so, they suffered significant casualties, especially from blows of the powerful post-abdomen of Simocephalus. The nature of the cladoceran-worm interaction is therefore far from simple: in addition to the ‘chemical communication’ that is present, it has a predatory component (worms trying to feed on cladocerans) but the reverse might also be true (cladocerans filtering out tissues of disrupted Aeolosoma). Since both worms and cladocerans feed on algae, exploitative competition also seems to be involved. In this, the worms appear to be the inferior partner, although none of the experiments lasted long enough to drive any of the competing partners to extinction. [ABSTRACT FROM AUTHOR]

Between 1995 and 1999, we surveyed the large branchiopods (Crustacea, Branchiopoda) of Numidia, the coastal plain of northeastern Algeria. Samples from ca 100 sites yielded two species of Anostraca (Chirocephalus diaphanus, new to Numidia, and Tanymastix stagnalis), one notostracan (Lepidurus apus lubbocki) and one spinicaudatan (Cyzicus tetracerus). The absence of Streptocephalus torvicornis bucheti is noteworthy. An annotated check-list of all large branchiopods known from Algeria is also presented and discussed. Several species appear to be in danger of extinction. [ABSTRACT FROM AUTHOR]

Adult fairy shrimps, Streptocephalus proboscideus (Frauenfeld, 1873) reared separately using algae (Scenedesmus acutus Meyen), a large loricate rotifer (Brachionus calyciflorus Pallas, 1766) and mixtures of algal and animal diets (1 : 1 ratio on a dry weight basis) at a rate of 17 mug DW ml 1 day 1 produced a mean number of 184 +/- 38, 111 +/- 14, and 160 +/- 14 cysts per brood, respectively. Of these, the rotifer-only diet was significantly inferior to both other food types. Measurements of cyst volume revealed an effect of food type. With all three types, S. proboscideus produced cysts in the size range of 3.0-9.0 x 10[sup 6] mum[sup 3]. However, sizes smaller than 3:0 x 10[sup 6] mum[sup 3] occurred in algae-fed anostracans and those larger than 9:0 x 10[sup 6] mum[sup 3] in rotifer-fed individuals. When the mean cyst production was expressed in terms of volume instead of numbers, there was a suggestion that the mixture of algae and rotifers was the superior combination, while females reared on rotifers produced a significantly (38%) lower total cyst volume. Hatchability of cysts, either dried or un-dried, was not significantly different between treatments. Des adultes de l'Anostrace Streptocephalus proboscideus (Frauenfeld, 1873), ont ete eleves en utilisant separement des algues (Scenedesmus acutus Meyen), un grand rotifere (Brachionus calyciflorus Pallas, 1766) et des melanges d'aliments algaux et animaux (proportion 1 : 1 sur la base du poids sec) a un taux de 17 mug DW ml[sup -1] jour[sup -1]. Ils ont produit un nombre moyen de cystes de, respectivement, 184 +/- 38, 111 +/- 14 et 160 +/- 14 par ponte. Parmi ces regimes, celui de rotiferes exclusivement etait significativement inferieur aux deux autres. Les mesures de volume des cystes revelaient un effet du type de nourriture. Avec les trois types, S. proboscideus produisait des cystes dans la gamme de tailles de 3,0-9,0 x 10[sup 6] mum[sup 3]. Cependant, des tailles inferieures a 3,0 x 10[sup 6] mum[sup 3] etaient observees chez les Anostraces algivores et des tailles superieures a 9,0 x 106 mum[sup 3] chez les individus nourris de rotiferes. Quand la production moyenne de cystes etait exprimee, non en terme de nombre, mains en volume, il semblait que le melange d'algues et de rotiferes etait la meilleure combinaison, alors que les femelles nourries de rotiferes produisaient un volume total de cystes significativement inferieur (38%). La capacite d'eclosion des cystes, seches ou non, ne differait pas de facon significative suivant les traitements. [ABSTRACT FROM AUTHOR]

The relative response of Kodak SB film has been measured with a pulsed-laser Al plasma x-ray source in the energy region delimited by the absorption edges of Br (1599 eV) and of Ag (3351 eV) in the photographic emulsion. The data of optical density versus exposure were obtained by recording spectra at different exposures which were controlled by placing stepped Be filters. A significant variation has been observed with earlier results obtained with continuous x-ray sources at high optical densities. The data may be fit with a simple expression of exposure L determined with an arbitrary constant L0 as a function of optical density D with only two parameters, Dsat and k: L = L0/(Dsat/D - 1)1/k. It is found that Dsat=3.45 and k=0.92 over the entire energy range. [ABSTRACT FROM AUTHOR]

Particle-γ coincidence measurements were carried out for the systemNe+Ni at 44 MeV/A. Discrete lines in the coincidence and singles γ-ray spectra were attributed to transitions between low-spin levels of residual nuclei with masses between A = 46 and A = 60. The associated particle multiplicities were found to increase with decreasing mass number. The results are discussed in the framework of a « participant-spectator » model for the reaction mechanism. [ABSTRACT FROM AUTHOR]

The lifetimes of nine levels inF have been measured by using the DSAM and theHe(O, p)F inverse reaction at 21 MeV incident energy on Al backings. Particle-gamma coincidence was employed. Levels (MeV) and corresponding lifetime (ps) deduced by a line shape analysis are as follows: 1.70 (0.897±0.057), 2.10 (4.93±0.78), 2.52 (0.554±0.045), 3.06 (<0.004), 3.13 (0.343±0.022), 3.36 (0.451±0.034), 3.72 (<0.007), 3.79 (1.90±0.20) and 3.84 (0.021±0.004). [ABSTRACT FROM AUTHOR]

Commercial fluorine production is conducted from KF.2HF melts at 85∘C in Monel cells that are subject to corrosion. Here we report studies of passivation and depassivation of the Monel in relation to that of Ni, its principal (65 wt % ) constituent, by means of cyclic voltammetry and recording of open-circuit potential-relaxation transients. The latter exhibit arrests at characteristic Flade-type potentials and lead to information on the kinetics of passive film breakdown. The role of diffusion processes in such breakdown and film dissolution is evaluated using the rotating disc electrode technique which enables comparisons to be made with the passivation behaviour of the separate main components of Monel, viz. Ni and Cu. [ABSTRACT FROM AUTHOR]

The process of electrolytic production of fluorine is conducted in a melt of KF.2HF at about 85°C. The metallic cell materials, copper and copper–nickel alloys (Monel), and the steel electrodes that are used as the cathode, are subject to substantial corrosion in the liquid electrolyte. Comparative studies are reported on the relative extent of corrosion of copper and nickel in the above melt, and the respective passivation behaviours of these two metals. The formation of fluoride films on the two metals is examined by means of cyclic voltammetry and complementarily through recording of open-circuit potential-decay transients, following passivation. Flade behaviour is observed and the role of diffusion-controlled processes in depassivation is quantitatively evaluated. Weight-change measurements also support the electrochemically derived results. The passive film at Ni is much less easily reducible than at Cu. [ABSTRACT FROM AUTHOR]

A spectroscopic study is performed for high spin states ofFe,Co andNi. To populate the investigated residues with a relevant cross section, the fusion evaporation reactions ofSi(Si, 2 pn)Fe,Si(Si, 2 np)Co andHe(Fe, n)Ni were chosen. To identify the new γ transitions and to build the energy level schemes, γ - γ coincidence techniques together with excitation functions were employed. Angular distributions and γ - γ angular correlations allowed us to assign the spin values of the nuclear states. The previous level scheme ofFe is extended into the region between 6.5-11 MeV of excitation energy, up to spin 27/2, while the yrast decay paths ofNi andCo are reported here for the first time. Experimental data are fairly well reproduced by Glaudemans' shell model calculations. [ABSTRACT FROM AUTHOR]

A letter to the editor is presented in response to an article about patients treated with opioids.

The behavior of boron incorporation into GaAs has been studied by x-ray photoelectron spectroscopy, x-ray diffraction, and atomic force microscopy. As the boron content of the film was increased, both the characteristic peak for the B 1 s core level at 188 eV and As Auger transition (260 eV) could be detected by XPS. At 550-600 °C, single crystalline films could only be grown for x≤0.06. Upon increasing the diborane flux in the gas phase, the film stoichiometry and the boron surface composition evolved rapidly towards a boron-rich subarsenide compound. This trend is followed by a clear degradation of the surface morphology and an increase in the surface roughness. A surface segregation of boron is suggested due to the high diborane vapor supersaturation needed during growth. [ABSTRACT FROM AUTHOR]

We have investigated the structure and optical properties of GaAs[sub 0.97]N[sub 0.03]/GaAs produced by metalorganic vapor phase epitaxy grown on GaAs surface at 520–550 °C. Using cross-sectional transmission electron microscopy and photoluminescence spectroscopy (PL), we show the presence of a 5–6-nm-thick nitrogen-rich interfacial region. The nitrogen composition near the interface is twice higher (x=0.038) than that of the bulk epilayer (x=0.016). PL data shows two peaks located at 1.05 and 1.18 eV associated to the interfacial region and the bulk layer, respectively. We discuss several mechanisms of surface enrichment of nitrogen that occurred during the first stage of GaAsN growth. © 2002 American Institute of Physics. [ABSTRACT FROM AUTHOR]

To study the x-ray laser beam deflection and divergence due to the refraction within the plasma, a specific diagnostic called CADIX has been developed at the Centre d'Etudes de Limeil-Valenton (CEL-V). When the beam refraction analysis is required a multilayer mirror is inserted on the x-ray laser output beam. It selects the lasing wavelengths and reflects them to an off-axis streak camera which records x rays as a function of time and angle. A detailed description of the instrument is presented including multilayer mirror calibration at the LURE (Laboratoire pour L'Utilisation du Rayonnement Synchrotron, Orsay, France). An experimental measurement on neon-like silver amplification is presented and analyzed with the response of the mirror. An important refraction effect is observed. [ABSTRACT FROM AUTHOR]

The article discusses the 13th International Rotifer Symposium (Rotifera XIII) that was held in Shillong, India from November 18-24, 2012. Topics include inaugural function of Rotifera XIII, taxonomy, and zoogeography. The symposium featured several participants including B. K. Sharma, R. L. Wallace, and E. J. Walsh.

The production cross sections ofLi in its ground and first excited states have been measured at 14°, 120°, 150°, for the 742 MeVNe+Ni reaction. Hauser-Feshbach calculations show that the backward angle data are consistent with an emission temperature greater than 6 MeV. This is in agreement with the values extracted from the slope of the energy spectra and indicates that the emitting source is equilibrated. [ABSTRACT FROM AUTHOR]

Mongolodiaptomus uenoi (Kikuchi, 1936), a little known diaptomid copepod from Taiwan and Indonesia, is re-described based on specimens from Thailand, and its relationship with its congeners is discussed. Toclear up the generic confusion between the closely allied genera Mongolodiaptomus Kiefer, Neodiaptomus Kiefer and Allodiaptomus Kiefer, anew criterion relating to the armature of the second exopodite-segment of the male right P5 is introduced. Accordingly, some dubious species of Neodiaptomus and Allodiaptomus are transferred to Mongolodiaptomus. [ABSTRACT FROM AUTHOR]