Response of embryonic coral reef fishes (Pomacentridae: Amphiprion spp.) to noise

We investigated the ability of embryonic clownfishes Amphiprion ephippium and A. rubrocinctus to detect sound during incubation in benthic nests. The heart rates of embryos within eggs were monitored as the young fish were exposed to sounds in the range of 100 to 1200 Hz at levels of 80 to 150 dB (re 1 μPa at 1 m) on each day of incubation. We found that, from 3 d after fertilisation, the heart rates of the embryos significantly increased when exposed to sound. As the embryos developed, a response in heart rate was found over a broader spectrum of sound (from 400 to 700 Hz at 3 d to a maximum of 100 to 1200 kHz at 9 d after fertilisation) and sensitivity also increased, with response threshold minima at 700 Hz dropping from 139.1 dB at 3 d to 88.3 dB at 9 d after fertilisation. We discuss these findings with respect to recent work that demonstrates the importance of sound as a settlement cue in coral reef fishes. © Inter-Research 2005.Natural Environment Research Council postgraduate fellowshipBritish AssociationInstitute of Museum and Library Service of the US Department of EducationNational Institute of Mental HealthNational Organization for Hearing ResearchKentucky Water Resources Research InstituteUniversity of Kentucky Research Committee grantAustralian Institute of Marine Science gran

A GIS based spatial decision support system for modelling contaminant intrusion into water distribution systems

The paper presents a GIS based spatial decision support system for modelling contaminant intrusion into water distribution system. Three models have been developed to simulate the process and risk of contamination. A seepage model predicts the contaminant zone of pollution sources and the change of concentration during migration through soil. A pipe condition assessment model ranks the condition of water pipe in terms of the potential of contaminant ingress. An ingress model combines the geometry algorithm with contaminant zone to obtain the potential pollution areas of water distribution pipe. The three models were integrated with ArcView GIS for supporting decision making for risk mitigation. Zone VIII of water supply system in Guntur, India was selected for the case study. The contaminant ingress potential and potential pollution area of water pipes were displayed as thematic maps in GIS. The areas resulting in high risk were identified from the GIS maps. The availability of resources for maintenance activities are limited in developing countries. Thus GIS based spatial decision support system helps to achieve maximum risk reduction

KAJIAN KEBUTUHAN INTEGRASI LAYANAN ANGKUTAN UMUM MASSAL DI KOTA SEMARANG DAN SEKITARNYA

Angkutan umum massal berbasis jalan telah dikembangkan oleh Pemerintah Kota Semarang sejak tahun 2009 hingga kini (Trans Semarang). Disisi lain, Pemerintah Provinsi Jawa Tengah sejak tahun 2017 juga melakukan hal yang sama di Wilayah Aglomerasi Kedungsepur (Trans Jateng). Namun terkesan berjalan sendiri-sendiri dan terjadi tumpang tindih layanan di ruas-ruas jalan tertentu. Dengan demikian, perlu dilakukan penelitian kebutuhan pengintegrasian layanan angkutan umum massal di Kota Semarang dan sekitarnya. Penelitian ini menggunakan pendekatan kuantitatif dengan analisis statistik deskriptif dan analisis spasial untuk mengetahui karakteristik dan pola permintaan perjalanan penggunanya. Hasil penelitian ini menunjukkan bahwa pengguna Koridor 1 dan 2 Trans Semarang dari luar Kota Semarang mencapai 39,14% dan 60,86% berasal dari dalam Kota Semarang. Pengguna dengan tujuan ke luar Kota Semarang mencapai 42,23% dan 57,77% tujuan di dalam Kota Semarang. Hal ini membuktikan bahwa Koridor 1 dan 2 mengakomodasi penumpang yang asal tujuannya cukup besar dari luar Kota Semarang. Terdapat tumpang tindih layanan mencapai 60% dari panjang lintasan di Koridor 1 Trans Jateng dan Koridor 2 Trans Semarang. Moda first mile pengguna Koridor 2 didominasi oleh Trans Jateng sebesar 51,51% dan last mile didominasi oleh penggunaan motor sebesar 48,10%. Penelitian ini menyarankan bahwa rute layanan Trans Jateng kedepannya dapat mengakomodir permintaan perjalanan di dalam kawasan penyangga dengan konsep layanan loop (mengelilingi), berbeda dari kondisi saat ini. Selanjutnya, layanan Trans Jateng yang menuju ke Kota Semarang dapat berhenti di titik perbatasan, dimana pergerakan kemudian dilayani oleh Trans Semarang dan diharapkan dapat memberikan layanan yang lebih baik kepada masyarakat di Kota Semarang dan sekitarnya.

Observation of inhibited electron-ion coupling in strongly heated graphite

Creating non-equilibrium states of matter with highly unequal electron and lattice temperatures (Tele≠Tion) allows unsurpassed insight into the dynamic coupling between electrons and ions through time-resolved energy relaxation measurements. Recent studies on low-temperature laser-heated graphite suggest a complex energy exchange when compared to other materials. To avoid problems related to surface preparation, crystal quality and poor understanding of the energy deposition and transport mechanisms, we apply a different energy deposition mechanism, via laser-accelerated protons, to isochorically and non-radiatively heat macroscopic graphite samples up to temperatures close to the melting threshold. Using time-resolved x ray diffraction, we show clear evidence of a very small electron-ion energy transfer, yielding approximately three times longer relaxation times than previously reported. This is indicative of the existence of an energy transfer bottleneck in non-equilibrium warm dense matter

Emergence of non-centrosymmetric topological insulating phase in BiTeI under pressure

The spin-orbit interaction affects the electronic structure of solids in various ways. Topological insulators are one example where the spin-orbit interaction leads the bulk bands to have a non-trivial topology, observable as gapless surface or edge states. Another example is the Rashba effect, which lifts the electron-spin degeneracy as a consequence of spin-orbit interaction under broken inversion symmetry. It is of particular importance to know how these two effects, i.e. the non-trivial topology of electronic states and Rashba spin splitting, interplay with each other. Here we show, through sophisticated first-principles calculations, that BiTeI, a giant bulk Rashba semiconductor, turns into a topological insulator under a reasonable pressure. This material is shown to exhibit several unique features such as, a highly pressure-tunable giant Rashba spin splitting, an unusual pressure-induced quantum phase transition, and more importantly the formation of strikingly different Dirac surface states at opposite sides of the material.Comment: 5 figures are include

Regional differences in APD restitution can initiate wavebreak and re-entry in cardiac tissue: A computational study

Background Regional differences in action potential duration (APD) restitution in the heart favour arrhythmias, but the mechanism is not well understood. Methods We simulated a 150 × 150 mm 2D sheet of cardiac ventricular tissue using a simplified computational model. We investigated wavebreak and re-entry initiated by an S1S2S3 stimulus protocol in tissue sheets with two regions, each with different APD restitution. The two regions had a different APD at short diastolic interval (DI), but similar APD at long DI. Simulations were performed twice; once with both regions having steep (slope > 1), and once with both regions having flat (slope < 1) APD restitution. Results Wavebreak and re-entry were readily initiated using the S1S2S3 protocol in tissue sheets with two regions having different APD restitution properties. Initiation occurred irrespective of whether the APD restitution slopes were steep or flat. With steep APD restitution, the range of S2S3 intervals resulting in wavebreak increased from 1 ms with S1S2 of 250 ms, to 75 ms (S1S2 180 ms). With flat APD restitution, the range of S2S3 intervals resulting in wavebreak increased from 1 ms (S1S2 250 ms), to 21 ms (S1S2 340 ms) and then 11 ms (S1S2 400 ms). Conclusion Regional differences in APD restitution are an arrhythmogenic substrate that can be concealed at normal heart rates. A premature stimulus produces regional differences in repolarisation, and a further premature stimulus can then result in wavebreak and initiate re-entry. This mechanism for initiating re-entry is independent of the steepness of the APD restitution curve

Social interactions through the eyes of macaques and humans

Group-living primates frequently interact with each other to maintain social bonds as well as to compete for valuable resources. Observing such social interactions between group members provides individuals with essential information (e.g. on the fighting ability or altruistic attitude of group companions) to guide their social tactics and choice of social partners. This process requires individuals to selectively attend to the most informative content within a social scene. It is unclear how non-human primates allocate attention to social interactions in different contexts, and whether they share similar patterns of social attention to humans. Here we compared the gaze behaviour of rhesus macaques and humans when free-viewing the same set of naturalistic images. The images contained positive or negative social interactions between two conspecifics of different phylogenetic distance from the observer; i.e. affiliation or aggression exchanged by two humans, rhesus macaques, Barbary macaques, baboons or lions. Monkeys directed a variable amount of gaze at the two conspecific individuals in the images according to their roles in the interaction (i.e. giver or receiver of affiliation/aggression). Their gaze distribution to non-conspecific individuals was systematically varied according to the viewed species and the nature of interactions, suggesting a contribution of both prior experience and innate bias in guiding social attention. Furthermore, the monkeys’ gaze behavior was qualitatively similar to that of humans, especially when viewing negative interactions. Detailed analysis revealed that both species directed more gaze at the face than the body region when inspecting individuals, and attended more to the body region in negative than in positive social interactions. Our study suggests that monkeys and humans share a similar pattern of role-sensitive, species- and context-dependent social attention, implying a homologous cognitive mechanism of social attention between rhesus macaques and humans

One-step hydrothermal synthesis of graphene decorated V2O5 nanobelts for enhanced electrochemical energy storage

Graphene-decorated V2O5 nanobelts (GVNBs) were synthesized via a low-temperature hydrothermal method in a single step. V2O5 nanobelts (VNBs) were formed in the presence of graphene oxide, a mild oxidant, which also enhanced the conductivity of GVNBs. From the electron energy loss spectroscopy analysis, the reduced graphene oxide (rGO) are inserted into the layered crystal structure of V2O5 nanobelts, which further confirmed the enhanced conductivity of the nanobelts. The electrochemical energy-storage capacity of GVNBs was investigated for supercapacitor applications. The specific capacitance of GVNBs was evaluated using cyclic voltammetry (CV) and charge/discharge (CD) studies. The GVNBs having V2O5-rich composite, namely, V(3)G(1) (VO/GO = 3:1), showed superior specific capacitance in comparison to the other composites (V(1)G(1) and V(1)G(3)) and the pure materials. Moreover, the V(3)G(1) composite showed excellent cyclic stability and the capacitance retention of about 82% was observed even after 5000 cycles.open

Theories for influencer identification in complex networks

In social and biological systems, the structural heterogeneity of interaction networks gives rise to the emergence of a small set of influential nodes, or influencers, in a series of dynamical processes. Although much smaller than the entire network, these influencers were observed to be able to shape the collective dynamics of large populations in different contexts. As such, the successful identification of influencers should have profound implications in various real-world spreading dynamics such as viral marketing, epidemic outbreaks and cascading failure. In this chapter, we first summarize the centrality-based approach in finding single influencers in complex networks, and then discuss the more complicated problem of locating multiple influencers from a collective point of view. Progress rooted in collective influence theory, belief-propagation and computer science will be presented. Finally, we present some applications of influencer identification in diverse real-world systems, including online social platforms, scientific publication, brain networks and socioeconomic systems.Comment: 24 pages, 6 figure