Chemically bound gold nanoparticle arrays on silicon: assembly, properties and SERS study of protein interactions

A highly reproducible and facile method for formation of ordered 2 dimensional arrays of CTAB protected 50 nm gold nanoparticles bonded to silicon wafers is described. The silicon wafers have been chemically modified with long-chain silanes terminated with thiol that penetrate the CTAB bilayer and chemically bind to the underlying gold nanoparticle. The silicon wafer provides a reproducibly smooth, chemically functionalizable and non-fluorescent substrate with a silicon phonon mode which may provide a convenient internal frequency and intensity calibration for vibrational spectroscopy. The CTAB bilayer provides a potentially biomimetic environment for analyte, yet allows a sufficiently small nanoparticle separation to achieve a significant electric field enhancement. The arrays have been characterized using SEM and Raman spectroscopy. These studies reveal that the reproducibility of the arrays is excellent both between batches (< 10% RSD) and across a single batch (< 5% RSD). The arrays also exhibit good stability, and the effect of temperature on the arrays was also investigated. The interaction of protein and amino acid with the nanoparticle arrays was investigated using Raman microscopy to investigate their potential in bio-SERS spectroscopy. Raman of phenylalanine and the protein bovine pancreatic trypsin inhibitor, BPTI were studied using 785 nm excitation, coincident with the surface plasmon absorbance of the array. The arrays exhibit SERS enhancements of the order of 2.6 x 104 for phenylalanine, the standard deviation on the relative intensity of the 1555 cm-1 mode of phenylalanine is less than 10% for 100 randomly distributed locations across a single substrate and less than 20% between different substrates. Significantly, comparisons of the Raman spectra of the protein and phenlyalanine in solution and immobilized on the nanoparticle arrays indicates that the protein is non-randomly orientated on the arrays. Selective SERS enhancements suggest that aromatic residues penetrate through the bilayer inducing conformational changes in the protein

Exploring the Role of Relational Practices in Water Governance Using a Game-Based Approach

The growing complexity and interdependence of water management processes requires the involvement of multiple stakeholders in water governance. Multi-party collaboration is increasingly vital at both the strategy development and implementation levels. Multi-party collaboration involves a process of joint decision-making among key stakeholders in a problem domain directed towards the future of that domain. However, the common goal is not present from the beginning; rather, the common goal emerges during the process of collaboration. Unfortunately, when the conflicting interests of different actors are at stake, the large majority of environmental multi-party efforts often do not reliably deliver sustainable improvements to policy and/or practice. One of the reasons for this, which has been long established by many case studies, is that social learning with a focus on relational practices is missing. The purpose of this paper is to present the design and initial results of a pilot study that utilized a game-based approach to explore the effects of relational practices on the effectiveness of water governance. This paper verifies the methods used by addressing the following question: are game mechanisms, protocols for facilitation and observation, the recording of decisions and results, and participant surveys adequate to reliably test hypotheses about behavioral decisions related to water governance? We used the “Lords of the Valley” (LOV) game, which focuses on the local-level management of a hypothetical river valley involving many stakeholders. We used an observation protocol to collect data on the quality of relational practices and compared this data with the quantitative outcomes achieved by participants in the game. In this pilot study, we ran the game three times with different groups of participants, and here we provide the outcomes within the context of verifying and improving the methods

Threat-sensitive anti-predator defence in precocial wader, the northern lapwing Vanellus vanellus

Birds exhibit various forms of anti-predator behaviours to avoid reproductive failure, with mobbing—observation, approach and usually harassment of a predator—being one of the most commonly observed. Here, we investigate patterns of temporal variation in the mobbing response exhibited by a precocial species, the northern lapwing (Vanellus vanellus). We test whether brood age and self-reliance, or the perceived risk posed by various predators, affect mobbing response of lapwings. We quantified aggressive interactions between lapwings and their natural avian predators and used generalized additive models to test how timing and predator species identity are related to the mobbing response of lapwings. Lapwings diversified mobbing response within the breeding season and depending on predator species. Raven Corvus corax, hooded crow Corvus cornix and harriers evoked the strongest response, while common buzzard Buteo buteo, white stork Ciconia ciconia, black-headed gull Chroicocephalus ridibundus and rook Corvus frugilegus were less frequently attacked. Lapwings increased their mobbing response against raven, common buzzard, white stork and rook throughout the breeding season, while defence against hooded crow, harriers and black-headed gull did not exhibit clear temporal patterns. Mobbing behaviour of lapwings apparently constitutes a flexible anti-predator strategy. The anti-predator response depends on predator species, which may suggest that lapwings distinguish between predator types and match mobbing response to the perceived hazard at different stages of the breeding cycle. We conclude that a single species may exhibit various patterns of temporal variation in anti-predator defence, which may correspond with various hypotheses derived from parental investment theory

Expansion of Nature Conservation Areas: Problems with Natura 2000 Implementation in Poland?

In spite of widespread support from most member countries’ societies for European Union policy, including support for the sustainable development idea, in many EU countries the levels of acceptance of new environmental protection programmes have been and, in particular in new member states, still are considerably low. The experience of the countries which were the first to implement union directives show that they cannot be effectively applied without widespread public participation. The goal of this study was, using the example of Poland, to assess public acceptance of the expansion of nature conservation in the context of sustainable development principles and to discover whether existing nature governance should be modified when establishing new protected areas. The increase in protected areas in Poland has become a hotbed of numerous conflicts. In spite of the generally favourable attitudes to nature which Polish people generally have, Natura 2000 is perceived as an unnecessary additional conservation tool. Both local authorities and communities residing in the Natura areas think that the programme is a hindrance, rather than a help in the economic development of municipalities or regions, as was initially supposed. This lack of acceptance results from many factors, mainly social, historic and economic. The implications of these findings for current approach to the nature governance in Poland are discussed

A Hipparcos study of the Hyades open cluster: Improved colour-absolute magnitude and Hertzsprung-Russell diagrams

Hipparcos parallaxes fix distances to individual stars in the Hyades cluster with an accuracy of 6%. We use the Hipparcos (and Tycho-2) proper motions, which have a larger relative precision than the trigonometric parallaxes, to derive ~3 times more precise distance estimates, by assuming that all members share the same space motion. The improved parallaxes as a set are statistically consistent with the Hipparcos parallaxes. The new parallaxes confirm that the Hipparcos measurements are correlated on small angular scales, consistent with the limits specified in the Hipparcos Catalogue, though with significantly smaller `amplitudes' than claimed by Narayanan & Gould. The colour-absolute magnitude diagram of the cluster based on the new paral- laxes shows a well-defined main sequence with two gaps/turn-offs. These features provide the first direct observational support of Boehm-Vitense's prediction that (the onset of) surface convection in stars affects their B-V colours. We present and discuss the theoretical HRD for an objectively defined set of 88 high-fidelity members of the cluster as well as the delta Scuti star theta^2 Tau, the giants delta^1, theta^1, epsilon, and gamma Tau, and the white dwarfs V471 Tau and HD 27483 (all of which are also members). The precision with which the new parallaxes place individual Hyades members in the Hertz- sprung-Russell diagram is limited by (systematic) uncertainties related to the transformations from observed colours and absolute magnitudes to effective temperatures and luminosities. The new parallaxes provide stringent constraints on the calibration of such transformations when combined with theoretical stellar evolutionary modelling, tailored to the chemical composition and age of the Hyades, over the large stellar mass range probed by Hipparcos.Comment: 41 pages, 20 PostScript figures (24 files), LaTeX using lscape.sty and psfig.sty; accepted for publication in Astronomy & Astrophysics; data in electronic format may be obtained from the author

Application of PHA method for assessing risk of failure on the example of sewage system in the city of Krakow

Systemy kanalizacyjne mogą stanowić potencjalne niebezpieczeństwo, zagrażać środowisku, użytkownikom systemu oraz najbliższemu jego otoczeniu. W analizie tych systemów powinno się więc uwzględniać zarówno ocenę niezawodności funkcjonowania, jak również niezawodność bezpieczeństwa. Zwiększająca się liczba awarii, nierzadko ich katastrofalne skutki, uwarunkowania zewnętrzne pracy systemu narzucają takie właśnie podejście w ocenie i zarządzaniu tymi systemami. Ocena niezawodności funkcjonowania najczęściej sprowadza się do zagadnienia określania częstotliwości awarii i usuwania jej przyczyn. Niezawodność generuje bezpieczeństwo systemu, ale bezpośrednio nie określa jego wartości. Rozszerzając badania niezawodności funkcjonowania o badania procesów oddziaływania awarii na środowisko oraz otoczenie, w tym także na społeczność dochodzi się do bezpieczeństwa [1, 13]. Bezpieczeństwo w ujęciu technicznym, czyli bezpieczeństwo techniczne zastępuje więc niezawodność. Bezpieczeństwo (stan niezawodności bezpieczeństwa NB) w skali makro w zakresie systemu kanalizacyjnego można zdefiniować przez analogię do systemów zaopatrzenia w wodę [12] jako stan gospodarki ściekowej umożliwiający zebranie, odprowadzenie oraz oczyszczenie bieżącej i perspektywicznej ilości ścieków sanitarnych (komunalnych) oraz deszczowych, przy zachowaniu wymagań sanitarnych, ochrony środowiska i utrzymania porządku publicznego. Zaprezentowana w pracy ocena ryzyka uszkodzeń sieci kanalizacyjne miasta Krakowa, wykorzystująca metodę wstępnej analizy zagrożeń PHA ma charakter dyskusyjny. Ocenę tą poprzedzono charakterystyką oceny niezawodności i bezpieczeństwa omawianego systemu, jako działań niezbędnych do oceny ryzyka oraz niezbędnymi informacjami o przyczynach i skutkach awarii sieci kanalizacyjnych. Po scharakteryzowaniu procedury metody PHA, wykorzystując matrycę ryzyka, oszacowano ryzyko wystąpienia stwierdzonych rodzajów uszkodzeń (rozszczelnienie kanału, załamanie kanału, odkształcenie kanału, uszkodzenie studni, pękniecie kanału i inne) przy pomocy wskaźnika częstości uszkodzeń, na podstawie zaproponowanych wartości kategorii prawdopodobieństwa i kategorii skutku. Niemożność porównania wyników tej oceny z danymi literaturowymi wynika z braku takich danych w literaturze, odnoszących się do sieci kanalizacyjnych.Sewage systems may pose a potential danger, threatening the environment, users of the system and its nearest surroundings. The analysis of these systems should therefore take into account both assessment of reliability of functioning, as well as the reliability of safety. Increasing number of failures, often their disastrous consequences, external conditions of the system dictate this approach in assessing and managing those systems. Evaluation of reliability of functioning is mostly simplified to the issue of determining the frequency of failures and removing its causes. Reliability generates safety of system, but does not directly determine its value. Extending tests of reliability of functioning with research on process of failures impact on the environment and surroundings, including the community, leads to safety. Therefore safety in terms of technology, that is technical safety replaces reliability. Safety (the state of safety reliability) at the macro level in the area of sewage system can be defined by analogy to water supply systems as a condition of sewage management enabling collection, transportation treatment of current and prospective quantity of sewage (municipal) and rainwater, at maintaining sanitary, environmental protection and maintenance of public order requirements. The paper evaluates the technical risk for the sewage network of the city of Krakow. The basis for calculations are field studies concerning operation of the said network, with the focus on technical data (network type, length, materials, size) and the failure rate information (type and duration of failure, unwanted event frequency). A two-dimensional matrix for failure risk in the pipelines was prepared with consideration to the type of pipeline and the material, as well as a risk map for pipeline malfunction. Obviously, the number of factors may be extended. In order to perform such analyses and add new factors, an appropriate database is needed, while in the case of sewage systems there is still little data collected. The evaluated risk of failure for the studied network was discovered to be in the tolerated and controlled-risk groups. The matrices and technical risk maps can be useful in the process of optimizing the operation of the sewage network, e.g. in planning and executing repair works