4,295 research outputs found
A review of policies and strategies affecting the peri-urban interface
As discussed elsewhere (Adell, 1999; Allen, 1999), whilst there is no accepted definition of what precisely constitutes the "peri-urban interface", the project team has identified at least three different approaches from where it has been conventionally conceptualised. These approaches may be classified according to the set of variables they choose to emphasise: physical attributes, such as proximity to the city and poor infrastructure; socio-economic variables; or urban-rural flows (of people, energy, goods)
Anaerobic membrane bioreactors: Are membranes really necessary?
Membranes themselves represent a significant cost for the full scale application of anaerobic membrane bioreactors (AnMBR). The possibility of operating an AnMBR with a self-forming dynamic membrane generated by the substances present in the reactor liquor would translate into an important saving. A self-forming dynamic membrane only requires a support material over which a cake layer is formed, which determines the rejection properties of the system. The present research studies the application of self-forming dynamic membranes in AnMBRs. An AnMBR was operated under thermophilic and mesophilic conditions, using woven and non woven materials as support for the dynamic membranes. Results showed that the formation of a cake layer over the support materials enables the retention of more than 99% of the solids present in the reactor. However, only low levels of flux were achieved, up to 3 L/m2 x h, and reactor operation was unstable, with sudden increases in filtration resistance, due to excessive cake layer formation. Further fine-tuning of the proposed technology involves looking for conditions that can control effectively cake layer formatio
Chimpanzees (Pan troglodytes) produce the same types of âlaugh facesâ when they emit laughter and when they are silent
The ability to flexibly produce facial expressions and vocalizations has a strong impact on the way humans communicate, as it promotes more explicit and versatile forms of communication. Whereas facial expressions and vocalizations are unarguably closely linked in primates, the extent to which these expressions can be produced independently in nonhuman primates is unknown. The present work, thus, examined if chimpanzees produce the same types of facial expressions with and without accompanying vocalizations, as do humans. Forty-six chimpanzees (Pan troglodytes) were video-recorded during spontaneous play with conspecifics at the Chimfunshi Wildlife Orphanage. ChimpFACS was applied, a standardized coding system to measure chimpanzee facial movements, based on FACS developed for humans. Data showed that the chimpanzees produced the same 14 configurations of open-mouth faces when laugh sounds were present and when they were absent. Chimpanzees, thus, produce these facial expressions flexibly without being morphologically constrained by the accompanying vocalizations. Furthermore, the data indicated that the facial expression plus vocalization and the facial expression alone were used differently in social play, i.e., when in physical contact with the playmates and when matching the playmates' open-mouth faces. These findings provide empirical evidence that chimpanzees produce distinctive facial expressions independently from a vocalization, and that their multimodal use affects communicative meaning, important traits for a more explicit and versatile way of communication. As it is still uncertain how human laugh faces evolved, the ChimpFACS data were also used to empirically examine the evolutionary relation between open-mouth faces with laugh sounds of chimpanzees and laugh faces of humans. The ChimpFACS results revealed that laugh faces of humans must have gradually emerged from laughing open-mouth faces of ancestral apes. This work examines the main evolutionary changes of laugh faces since the last common ancestor of chimpanzees and humans
âWestern Mediterraneanâ (WM) broad band network: permanent seismic monitoring at the Ibero-Maghrebian region
The âIbero-Maghrebianâ region, a western part of the Eurasia-Africa plate boundary, is a broad deformation area without a well defined plate boundary line, comprising the Southern part of the Iberian Peninsula, the Northwestern part of Africa, the Gulf of Cadiz and the Alboran Sea, with a convergence between Iberia and Africa at some mm/year (Nuvel-1A model, DeMets et al, 1994) in a NNW-SSE direction, and a dif- ferential motion at Alboran Sea area (Buforn et al, 1995). Although seismic activity is characterized by a low to moderate magnitude and shallow depth earthquakes, big events are also well documented, among others: Lisbon earthquake (1755, I0= X), Gulf of Cadiz (1969, Ms= 8.1), or, more recently Bourmedes (2003, Mw= 7.1), some them with an associated tsunami, like Lisbon or Bourmedes earthquakes. An interme- diate seismic activity is also clearly registered from Gulf of Cadiz to mid Alboran Sea (Martin Davila and Pazos, 2003), and very deep earthquakes (h> 650 km) have been registered at Granada basin (1954, M= 7.0).
In order to better study the seismic characteristics of this area, from 1996 on, ROA and the University Complutense of Madrid (UCM), with the collaboration of Geo- forschungZentrum of Potsdam (GFZ), have deployed a broad band seismic net with stations located at Southern Spain and Spanish possessions located Northern Africa,
mainly surrounding the Alboran Sea, complementing the previously installed ROA SP and LP stations. This net has been named as âWestern Mediterranean netâ (WM FDSN code). As net was evolving, new Institutes and stations joined WM net, such a way at present is formed by ten stations located at: San Fernando (SFS), MaĚlaga (MALA), Cartagena (CART), and Evora (UEVO, University of Evora, Portugal) at Iberian peninsula, MahoĚn (MAHO) at Minorca island, three stations at Melilla (MELI), PenĚoĚn de VeĚlez-Gomera (PVLZ), and Ceuta (CEU) at Spanish villages located Northern Africa in South Alboran Sea area, and Averroes (AVE) and Ifrane (IFR) installed at Morocco mainland as a joined effort among ISRABAT (Institut Scientifique, Univer- siteĚ Mohammed V), ROA and UCM. Most stations are collocated with permanent geodetic GPS stations (GaĚrate et al, 2004). Next future plans include the installation of five stations by U. Evora at Southern Portugal area, a new station at Morocco by ISRABAT, ROA and UCM and also a new station at Oran (Algeria), as a collaboration among UniversiteĚ dâOran (Algeria), ROA and UCM. All them will be associated to WM net.
All WM network stations include Streckeisen STS-2 sensor, a Quanterra or Earth Data digitizer, and a SeiscomP process system (Heinloo, 2004), and all them are available in real time via phone modem or Internet, except PVLZ and CEU, which will be in short.
In this work, partly funded by the Spanish Ministry of Education and Science (MEC) through the project REN2006-10311-C03-01/02 (RISTE), we will present the present status, the next future plans and some related activities of WM net
Osmotic Edema Rapidly Increases Neuronal Excitability Through Activation of NMDA Receptor-Dependent Slow Inward Currents in Juvenile and Adult Hippocampus.
Cellular edema (cell swelling) is a principal component of numerous brain disorders including ischemia, cortical spreading depression, hyponatremia, and epilepsy. Cellular edema increases seizure-like activity in vitro and in vivo, largely through nonsynaptic mechanisms attributable to reduction of the extracellular space. However, the types of excitability changes occurring in individual neurons during the acute phase of cell volume increase remain unclear. Using whole-cell patch clamp techniques, we report that one of the first effects of osmotic edema on excitability of CA1 pyramidal cells is the generation of slow inward currents (SICs), which initiate after approximately 1âmin. Frequency of SICs increased as osmolarity decreased in a dose-dependent manner. Imaging of real-time volume changes in astrocytes revealed that neuronal SICs occurred while astrocytes were still in the process of swelling. SICs evoked by cell swelling were mainly nonsynaptic in origin and NMDA receptor-dependent. To better understand the relationship between SICs and changes in neuronal excitability, recordings were performed in increasingly physiological conditions. In the absence of any added pharmacological reagents or imposed voltage clamp, osmotic edema induced excitatory postsynaptic potentials and burst firing over the same timecourse as SICs. Like SICs, action potentials were blocked by NMDAR antagonists. Effects were more pronounced in adult (8-20 weeks old) compared with juvenile (P15-P21) mice. Together, our results indicate that cell swelling triggered by reduced osmolarity rapidly increases neuronal excitability through activation of NMDA receptors. Our findings have important implications for understanding nonsynaptic mechanisms of epilepsy in relation to cell swelling and reduction of the extracellular space
Spatial Evolution of Resonant Harmonic Mode Triads in a Blasius Boundary Layer
Blasius boundary layer evolution is studies by means of bicoherence calculations. The layer is acoustically excited at the T-S frequency to provide a controlled transition. Measurements are made using a smooth surface as well as various roughness patterns. The bicoherence calculations are used to determine the extent to which frequency resonant velocity fluctuation waves can participate in energy exchange. The emphasis is on downstream variation of the individual interactions among harmonic modes. A limited picture of the role of quadratic wave interactions is revealed
AIM for change: Supporting first year learning of best practice in scientific writing with a flipped, embedded academic integrity module
Scientific writing is a fundamental professional skill but remains a daunting task for the trainee scientist. Understanding, synthesising and integrating research are essential scientific writing skills; however, appropriate use of the literature continues to be problematic with many students accidentally plagiarising because they lack paraphrasing and citation skills [1]. Materials to support students in developing these skills tend to be decontextualised, generic, and even ignored if they simply inform students about what plagiarism is without providing opportunities for hands-on training [2]. Furthermore, appropriate use of literature varies within professional disciplines, causing potential confusion if learned outside a given course of study. As writing scientific reports accounts for a substantial proportion of most undergraduate science assessments, discipline specific academic literacy resources must be embedded early in the science curriculum. Such resources enhance student learning, build confidence and support the development of competent, employable science graduates. Integrating discipline-specific resources requires disciplinary experts to re-evaluate curriculum design and teaching practice. At our university, this re-evaluation is encouraged through both institutionally driven and grassroots level initiatives. For example, the university promotes the embedding of First Year curriculum principles [3] into subject design for a scaffolded transition to university learning and has implemented the First Year Experience project, in which small interdisciplinary teams embark on curriculum change and share their findings at faculty-developed Communities of Practice. These initiatives supported our project on embedding an interactive online Academic Integrity Module (AIM) on academic literacy and professional skills in scientific writing in a first year core subject. By blending out-of-classroom exercises (flipped learning approach) with workshops incorporating peer-to-peer interaction, students engaged in independent learning that was strengthened in a supportive, âlearning by doingâ environment. In the pilot program, engagement in the project was strong, as 60% of students completed the bespoke AIM even though no marks were associated with it. Evaluation surveys revealed that students identified the importance of academic integrity to a science career (Likert score 4.19, n=245) and had a better understanding of why the correct use of the scientific literature was important for a scientific career (Likert score 4.17, n=247). On average, students who completed the online AIM performed better for the referencing criterion in their assessment than those who did not attempt the AIM. Following the principles of good practice of SoTL [4] we disseminated our findings locally via university forums, showcasing our working example of embedding institutional initiatives in the discipline of science. This has lead to collaboration with other disciplines to further develop and reframe our online AIM for different contexts. Our project clearly demonstrates how institutional initiatives can be successfully implemented and embedded into a large, first year science subject with positive outcomes for studentsâ learning and changing practice within the University. 1.Devlin, Gray (2007) Higher Education Research & Development, 26:181-198. 2.Bretag et al. (2014) Studies in Higher Education, 39:1150-1169. 3.Kift et al. (2010) The International Journal of the First Year in Higher Education, 1:1-20. 4.Felten (2013) Teaching & Learning Inquiry: The ISSOTL Journal, 1:121-125
High-frequency Alfven waves in multi-ion coronal plasma : observational implications
We investigate the effects of high-frequency (of order ion gyrofrequency) AlfvĂŠn and ion-cyclotron waves on ion emission lines by studying the dispersion of these waves in a multi-ion coronal plasma. For this purpose we solve the dispersion relation of the linearized multifluid and Vlasov equations in a magnetized multi-ion plasma with coronal abundances of heavy ions. We also calculate the dispersion relation using nonlinear one-dimensional hybrid kinetic simulations of the multi-ion plasma. When heavy ions are present the dispersion relation of parallel propagating AlfvĂŠn cyclotron waves exhibits the following branches (in the positive Ί â k quadrant): right-hand polarized nonresonant and left-hand polarized resonant branch for protons and each ion. We calculate the ratio of ion to proton velocities perpendicular to the direction of the magnetic field for each wave modes for typical coronal parameters and find strong enhancement of the heavy ion perpendicular fluid velocity compared with proton perpendicular fluid velocity. The linear multifluid cold plasma results agree with linear warm plasma Vlasov results and with the nonlinear hybrid simulation model results. In view of our findings we discuss how the observed nonthermal line broadening of minor ions in coronal holes may relate to the high-frequency wave motions
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