Behavior and mortality of caught-and-released bonefish (Albula spp.) in Bahamian waters with implications for a sustainable recreational fishery

Bonefish (Albula spp.) are a widely distributed group of morphologically indistinguishable marine fish species, that provide a recreational sport fishery, that is important for many local economies. Although the majority of angled bonefish are released following capture, little is known about their behavior or post-release survival. Using ultrasonic transmitters and small visual floats, we assessed behavior and mortality of bonefish following catch-and-release angling at spring water temperatures (25.5-27.3 °C) in two regions of the Bahamas with differing shark abundances. All observed mortality occurred within 30 min of release and was a direct result of predation by sharks. In the low shark abundance areas, all released bonefish survived, whereas in the high shark abundance areas, some mortality (39%) was observed. Exhaustively angled fish exposed to air had problems maintaining equilibrium following release. These fish typically spent substantial periods of the first 30 min post-release remaining stationary, then moved in rapid bursts. The results of this study, highlight the benefits of angling and releasing bonefish quickly, minimizing handling and particularly air exposure. Furthermore, when shark predation threat is high, anglers should avoid releasing bonefish in the immediate area. The conservation of exploited recreational bonefish fisheries will depend upon the development and dissemination of science-based catch-and-release strategies.     

Experimental repetitive quantum error correction

The computational potential of a quantum processor can only be unleashed if errors during a quantum computation can be controlled and corrected for. Quantum error correction works if imperfections of quantum gate operations and measurements are below a certain threshold and corrections can be applied repeatedly. We implement multiple quantum error correction cycles for phase-flip errors on qubits encoded with trapped ions. Errors are corrected by a quantum-feedback algorithm using high-fidelity gate operations and a reset technique for the auxiliary qubits. Up to three consecutive correction cycles are realized, and the behavior of the algorithm for different noise environments is analyzed.     

Parallel patterns of evolution in the genomes and transcriptomes of humans and chimpanzees

The determination of the chimpanzee genome sequence provides a means to study both structural and functional aspects of the evolution of the human genome. Here we compare humans and chimpanzees with respect to differences in expression levels and protein-coding sequences for genes active in brain, heart, liver, kidney, and testis. We find that the patterns of differences in gene expression and gene sequences are markedly similar. In particular, there is a gradation of selective constraints among the tissues so that the brain shows the least differences between the species whereas liver shows the most. Furthermore, expression levels as well as amino acid sequences of genes active in more tissues have diverged less between the species than have genes active in fewer tissues. In general, these patterns are consistent with a model of neutral evolution with negative selection. However, for X-chromosomal genes expressed in testis, patterns suggestive of positive selection on sequence changes as well as expression changes are seen. Furthermore, although genes expressed in the brain have changed less than have genes expressed in other tissues, in agreement with previous work we find that genes active in brain have accumulated more changes on the human than on the chimpanzee lineage.     

Identification and quantification of zeaxanthin esters in plants using liquid chromatography-mass spectrometry

It has been suggested that lutein and zeaxanthin may decrease the risk for age-related macular degeneration. Surprisingly, oleoresins rich in zeaxanthin are not yet available on the market. Several authors have reported enhanced stability of esterified xanthophylls, so plants containing zeaxanthin esters were investigated to establish valuable sources for the production of durable oleoresins. Liquid chromatography-atmospheric pressure chemical ionization mass spectrometry [LC-(APCI)MS] was used to unequivocally identify zeaxanthin esters of a standard mixture and in several plant extracts. Zeaxanthin esters were quantified on the basis of their respective molecular masses using zeaxanthin for calibration; total zeaxanthin was determined after saponification of aliquots of the extracts. Thus, dried wolfberries (Lycium barbarum), Chinese lanterns (Physalis alkekengi), orange pepper (Capsicum annuum), and sea buckthorn (Hippophae rhamnoides) proved to be valuable zeaxanthin ester sources. The present LC-MS method allows for an even more detailed analysis of zeaxanthin esters than reported previously.     

Vernachlässigte Phosphor‐ und Kaliumdüngung im ökologischen Landbau senkt die biologische Stickstofffixierung bei Rotklee und den Kornertrag bei nachfolgendem Hafer

Neglected P and K fertilization in organic farming reduces N₂ fixation and grain yield in a red clover‐oat rotation N₂ fixation is the most important N source in organic farming. An insufficient P, K, and S supply to legumes may reduce their N₂ fixation capacity. Consequently, the total yield of plant production may also be reduced. This problem was studied in a pot experiment with red clover followed by oat. Soil was taken from a field where organic farming had been practiced for more than 30 years without applying any mineral fertilizers or buying additional fodder. The soil (luvisol from loess) was characterized by: pH (CaCl₂) 5.4; lactate‐soluble (CAL) P 5 mg kg^–1 and K 110 mg kg^–1. 6 kg dry soil were mixed with 400 mg P applied as (i) triplesuperphosphate (TSP), (ii) rock phosphate (RP) or (iii) compost from organic household residues (BAK). An additional treatment (iv) with TSP received 1000 mg K as K₂SO₄ (TSP+K) and an additional treatment with RP (v) received only 200 mg P (RP/2). A control treatment received no fertilizer. P application significantly improved the P nutritional status of the plants (P content) and increased the N amount in the shoots of red clover (with 400 mg P per pot by 64 % to 139 % as compared to the control) and the dry matter (DM) yield by 60 % to 130 %. No significant differences between TSP and RP were found. The application of BAK resulted in a significantly higher N yield than the application of RP and TSP. The treatment TSP+K resulted in the highest DM yield (230 %), removal of P was 343 %, of K 228 %, and of N 239 % as compared to the control plants. This indicates a synergistic effect of P, K, and S on N₂ fixation, which was also found with BAK. Oat grown after red clover increased its grain yield by 132 % (200 mg P as RP) to 165 % (400 mg P treatments). This was mainly due to a higher P uptake (up to 172 %) and a higher N uptake (up to 172 %) as compared to the control.     

Impact features on Stardust: implications for comet 81P/Wild 2 dust

Particles emanating from comet 81P/Wild 2 collided with the Stardust spacecraft at 6.1 kilometers per second, producing hypervelocity impact features on the collector surfaces that were returned to Earth. The morphologies of these surprisingly diverse features were created by particles varying from dense mineral grains to loosely bound, polymineralic aggregates ranging from tens of nanometers to hundreds of micrometers in size. The cumulative size distribution of Wild 2 dust is shallower than that of comet Halley, yet steeper than that of comet Grigg-Skjellerup.     

Structure of an intermediate state in protein folding and aggregation

Protein-folding intermediates have been implicated in amyloid fibril formation involved in neurodegenerative disorders. However, the structural mechanisms by which intermediates initiate fibrillar aggregation have remained largely elusive. To gain insight, we used relaxation dispersion nuclear magnetic resonance spectroscopy to determine the structure of a low-populated, on-pathway folding intermediate of the A39V/N53P/V55L (A, Ala; V, Val; N, Asn; P, Pro; L, Leu) Fyn SH3 domain. The carboxyl terminus remains disordered in this intermediate, thereby exposing the aggregation-prone amino-terminal β strand. Accordingly, mutants lacking the carboxyl terminus and thus mimicking the intermediate fail to safeguard the folding route and spontaneously form fibrillar aggregates. The structure provides a detailed characterization of the non-native interactions stabilizing an aggregation-prone intermediate under native conditions and insight into how such an intermediate can derail folding and initiate fibrillation.