Emergent spatial patterns of competing benthic and pelagic algae in a river network: A parsimonious basin-scale modeling analysis

Algae, as primary producers in riverine ecosystems, are found in two distinct habitats: benthic and pelagic algae typically prevalent in shallow/small and deep/large streams, respectively. Over an entire river continuum, spatiotemporal patterns of the two algal communities reflect specificity in habitat preference determined by geomorphic structure, hydroclimatic controls, and spatiotemporal heterogeneity in nutrient loads from point- and diffuse-sources. By representing these complex interactions between geomorphic, hydrologic, geochemical, and ecological processes, we present here a new river-network-scale dynamic model (CnANDY) for pelagic (A) and benthic (B) algae competing for energy and one limiting nutrient (phosphorus, P). We used the urbanized Weser River Basin in Germany (7th-order; ~8.4 million population; ~46 K km2) as a case study and analyzed simulations for equilibrium mass and concentrations under steady median river discharge. We also examined P, A, and B spatial patterns in four sub-basins. We found an emerging pattern characterized by scaling of P and A concentrations over stream-order ω, whereas B concentration was described by three distinct phases. Furthermore, an abrupt algal regime shift occurred in intermediate streams from B dominance in ω≤3 to exclusive A presence in ω≥6. Modeled and long-term basin-scale monitored dissolved P concentrations matched well for ω>4, and with overlapping ranges in ω<3. Power-spectral analyses for the equilibrium P, A, and B mass distributions along hydrological flow paths showed stronger clustering compared to geomorphological attributes, and longer spatial autocorrelation distance for A compared to B. We discuss the implications of our findings for advancing hydro-ecological concepts, guiding monitoring, informing management of water quality, restoring aquatic habitat, and extending CnANDY model to other river basins

Drug elucidation: invertebrate genetics sheds new light on the molecular targets of CNS drugs

Many important drugs approved to treat common human diseases were discovered by serendipity, without a firm understanding of their modes of action. As a result, the side effects and interactions of these medications are often unpredictable, and there is limited guidance for improving the design of next-generation drugs. Here, we review the innovative use of simple model organisms, especially Caenorhabditis elegans, to gain fresh insights into the complex biological effects of approved CNS medications. Whereas drug discovery involves the identification of new drug targets and lead compounds/biologics, and drug development spans preclinical testing to FDA approval, drug elucidation refers to the process of understanding the mechanisms of action of marketed drugs by studying their novel effects in model organisms. Drug elucidation studies have revealed new pathways affected by antipsychotic drugs, e.g., the insulin signaling pathway, a trace amine receptor and a nicotinic acetylcholine receptor. Similarly, novel targets of antidepressant drugs and lithium have been identified in C. elegans, including lipid-binding/transport proteins and the SGK-1 signaling pathway, respectively. Elucidation of the mode of action of anesthetic agents has shown that anesthesia can involve mitochondrial targets, leak currents, and gap junctions. The general approach reviewed in this article has advanced our knowledge about important drugs for CNS disorders and can guide future drug discovery efforts

Connecting Students by Integrating the 3D Virtual and Real Worlds: We Need 3D Open Source Spaces to Keep Socialization, Communication and Collaboration Alive

Picture a world where imagination is the only limit; a world that stimulates students to learn, communicate, play and grow. The emergence of 3D Virtual Worlds has made this a virtual reality. Until recently this virtual experience has been separated from the real world by the limitations of software (proprietary systems), and constraints of hardware and networks (stationary consoles and network connections). Such separation limits the pedagogical utility that 3D Spaces can offer students. This article peeks around the corner of innovation by exploring a number of emergent open source developments that integrate the 3D Virtual and Real Worlds into a seamless reality, one that enhances pedagogical opportunities by integrating the practical and vocational actuality of the real world with the technical and imaginable possibilities of the Virtual Worlds. These possibilities are explored with reference to recent developments, pedagogical theory, and case studies in various open source 3D Virtual Worlds

Sex-specific differences in the impact of heavier body armour worn by law enforcement officers completing occupational tasks: a pilot study

Aim: to assess sex-specific impacts of heavier body armour in law enforcement officers completing occupational tasks.Design: A randomized counter-balanced study.Method: Ten qualified police officers of which six were female (mean height = 167.97 ± 3.67 cm, mean mass= 65.30 ± 10.57 kg) and four were male (mean height = 82.15 ± 6.98 cm, mean weight = 85.55 ± 9.96 kg) completed a functional movement screen for mobility and three occupational tasks wearing a law enforcement (2.1 kg) or military (6.4 kg) body armour system. Following paired samples t-tests, effect sizes(d) were calculated for the between-body armour type comparisons. Bond University Human Research Ethics Committee provided ethics approval (RO15803).Results: When military body armour was worn, female officers experienced a greater impact on their car exit and victim drag (d = 0.37, 0.02 respectively) when compared to males (d = 0.12, -0.41 respectively).Alternatively, male officers experienced a greater impact on their mobility and agility (d = -1.29, 0.57 respectively) when compared to females (d = -0.98, 0.31 respectively).Conclusion: Wearing heavier body armour had a greater effect on female officers in the car exit and victim drag measures and on male officers in the functional movement screen and agility measures. The impacts of wearing heavier body armour should not be considered the same between the sexes.Key Practice Points:• Heavy body armour systems may impede the sexes differently warranting consideration when rehabilitating and reconditioning police officers to return-to-work following injury

Sex-specific differences in fit between two different types of body armour: A pilot study

Aim: to assess sex-specific differences in wearability and comfort when wearing body armour.Design: A randomized counter-balanced study.Method: Ten participants (females n = 6, mean height = 167.97 ± 3.67 cm, mean mass = 65.30 ± 10.57 kg: males n = 4, mean height = 82.15 ± 6.98 cm, mean weight = 85.55 ± 9.96 kg) were included following eligibility criteria and assessed against occupational tasks for which they gave subjective feedback when wearing a law enforcement (2.1 kg) and military (6.4 kg) body armour system. Subjective feedback was provided on mannequin sketches and compared between sexes and body armour types. Bond University Human Research Ethics Committee provided ethics approval (RO15803).Results: Greater negative feedback was received, subjectively, from both sexes regarding the military body armour. Female participants recorded areas of most discomfort to include the neck, shoulder, chest, and hip, whilst males recorded areas to be the neck, shoulder, and abdomen. Females reported greater subjective concerns than males regarding body armour fit.Conclusion: With levels of discomfort associated with injury in police officers wearing body armour, the comfort and fit of body armour and differences between sexes must be considered. These differences require consideration when returning injured officers back to work, especially following brachial plexus palsy and meralgia paresthetica injuries.</div

Translational control of the SigR-directed oxidative stress response in streptomyces via IF3-mediated repression of a noncanonical GTC start codon

The major oxidative stress response in Streptomyces is controlled by the sigma factor SigR and its cognate antisigma factor RsrA, and SigR activity is tightly controlled through multiple mechanisms at both the transcriptional and posttranslational levels. Here we show that sigR has a highly unusual GTC start codon and that this leads to another level of SigR regulation, in which SigR translation is repressed by translation initiation factor 3 (IF3). Changing the GTC to a canonical start codon causes SigR to be overproduced relative to RsrA, resulting in unregulated and constitutive expression of the SigR regulon. Similarly, introducing IF3* mutations that impair its ability to repress SigR translation has the same effect. Thus, the noncanonical GTC sigR start codon and its repression by IF3 are critical for the correct and proper functioning of the oxidative stress regulatory system. sigR and rsrA are cotranscribed and translationally coupled, and it had therefore been assumed that SigR and RsrA are produced in stoichiometric amounts. Here we show that RsrA can be transcribed and translated independently of SigR, present evidence that RsrA is normally produced in excess of SigR, and describe the factors that determine SigR-RsrA stoichiometry.IMPORTANCE In all sigma factor-antisigma factor regulatory switches, the relative abundance of the two proteins is critical to the proper functioning of the system. Many sigma-antisigma operons are cotranscribed and translationally coupled, leading to a generic assumption that the sigma and antisigma factors are produced in a fixed 1:1 ratio. In the case of sigR-rsrA, we show instead that the antisigma factor is produced in excess over the sigma factor, providing a buffer to prevent spurious release of sigma activity. This excess arises in part because sigR has an extremely rare noncanonical GTC start codon, and as a result, SigR translation initiation is repressed by IF3. This finding highlights the potential significance of noncanonical start codons, very few of which have been characterized experimentally. It also emphasizes the limitations of predicting start codons using bioinformatic approaches, which rely heavily on the assumption that ATG, GTG, and TTG are the only permissible start codons

Enhancing and inhibiting stimulated Brillouin scattering in photonic integrated circuits

On-chip nonlinear optics is a thriving research field, which creates transformative opportunities for manipulating classical or quantum signals in small-footprint integrated devices. Since the length scales are short, nonlinear interactions need to be enhanced by exploiting materials with large nonlinearity in combination with high-Q resonators or slow-light structures. This, however, often results in simultaneous enhancement of competing nonlinear processes, which limit the efficiency and can cause signal distortion. Here, we exploit the frequency dependence of the optical density-of-states near the edge of a photonic bandgap to selectively enhance or inhibit nonlinear interactions on a chip. We demonstrate this concept for one of the strongest nonlinear effects, stimulated Brillouin scattering using a narrow-band one-dimensional photonic bandgap structure: a Bragg grating. The stimulated Brillouin scattering enhancement enables the generation of a 15-line Brillouin frequency comb. In the inhibition case, we achieve stimulated Brillouin scattering free operation at a power level twice the threshold

Tunable variation of optical properties of polymer capped gold nanoparticles

Optical properties of polymer capped gold nanoparticles of various sizes (diameter 3-6 nm) have been studied. We present a new scheme to extract size dependent variation of total dielectric function of gold nanoparticles from measured UV-Vis absorption data. The new scheme can also be used, in principle, for other related systems as well. We show how quantum effect, surface atomic co - ordination and polymer - nanoparticle interface morphology leads to a systematic variation in inter band part of the dielectric function of gold nanoparticles, obtained from the analysis using our new scheme. Careful analysis enables identification of the possible changes to the electronic band structure in such nanoparticles.Comment: 13 pages,7 figures, 1 tabl

Is Entrepreneurial Success Predictable? An Ex-Ante Analysis of the Character-Based Approach

This paper empirically analyzes whether the character-based approach, which focuses on the personality structure and the human capital of business founders, allows prediction of entrepreneurial success. A unique data set is used consisting of 414 persons whose personal characteristics were analyzed by different methods, namely an one-day assessment center (AC) and a standardized questionnaire, before they launched their business. Results are partly unexpected and weaker than previous ex-post findings: first, we found correlations between the AC data and the questionnaire in one subgroup only. Second, the predictive power of the AC data is slightly better than that of the questionnaire, but lower than expected in theory. Interestingly, for those subgroups where the AC data have low predictive power, the questionnaire does better. Third, when success is measured in terms of employees hired, the character-based approach is a poor predictor. Copyright 2008 The Authors.

Proporción diaria de alimento del diablillo antártico (pleuragramma antarcticum boulenger, 1902) en el este del mar de weddell

[EN] The daily ration of Pleuragramma antarcticum in the Eastern Weddell Sea was investigated from midwater and bottom trawl samples collected in the Antarctic in the summer of 1998. Using a gastric evacuation model that takes into account Weddell Sea temperature below zero and information on the prey type daily ration estimates were: 1.133% BW for immature fish of 10-16 cm and 0.484% BW for mature fish of 17-24 cm. The low daily ration intake was influenced by the low temperatures that limited the rate of gastric evacuation. This model seems more realistic than results from the classic Elliot & Persson and Eggers models that are also used in this paper, since their assumptions on feeding regularity are more rigid and they do not consider data of energy density of the prey[ES] La ración diaria de alimento de Pleuragramma antarcticum en el mar de Weddell es investigada en muestras de arrastres de fondo y pelágicas recogidas durante diferentes horas del día en el verano antártico de 1998. Utilizando un modelo de evacuación gástrica que tiene en cuenta la temperatura bajo del Mar de Weddell e información sobre el tipo de presa, las estimaciones de consumo diario fueron: 1.133% BW para peces inmaduros entre 10 -16 cm y 0.484% BW para peces maduros entre 17-24 cm. La baja ración diaria ingerida estuvo influida por las bajas temperaturas que limitan la tasa de evacuación gástrica. Este modelo parece más realista que los resultados de los modelos clásicos de Elliot & Persson and Eggers también empleados, ya que sus asunciones sobre su periodicidad de alimentación son más rígidas y no consideran datos de densidad energética de las presasThis work was conducted under the SCAR EASIZ programme, and was supported by the Alfred Wegener Institute and the Spanish Antarctic ProgrammePeer reviewe