Altitudinal effects on habitat selection in two sympatric pipistrelle species

Altitude can profoundly influence the distribution of mammals, although the majority of studies of altitudinal impacts on distribution and abundance examine large-scale effects in mountainous environments. We investigate the potential for altitudinal effects on within habitat distribution in common and soprano pipistrelle bats (Pipistrellus pipistrellus and Pipistrellus pygmaeus) over relatively small scales on the Isle of Man, an island with a maximum altitude of 620 m above sea level. While we found no differences in habitat or altitude usage between the two species, both showed a sharp decline in activity with small increases in altitude within all habitats. This decline was steepest in deciduous and conifer woodland, and more gradual in arable land and heathland. Activity also declined more quickly with increasing altitude in the centre of habitats compared with the edge, and where water was present compared with where water was absent. We suggest that altitude may limit distribution independent of habitat, and thus is an important factor to take into account, in combination with habitat, when designing mammalian conservation strategies

Initial Reports of the Deep Sea Drilling Project, vol. 85

Covering Leg 85 of the cruises of the Drilling Vessel Glomar Challenger Los Angeles, California, to Honolulu, Hawaii March-April 1982. Includes six chapters: 1. INTRODUCTION: BACKGROUND AND EXPLANATORY NOTES, DEEP SEA DRILLING PROJECT LEG 85, CENTRAL EQUATORIAL PACIFIC 2. SITE 571 3. SITE 572 4. SITE 573 5. SITE 574 6. SITE 57

Photoconductive Arrays on Insulating Substrates for High-Field Terahertz Generation

We report on the design, fabrication and characterisation of large-area photoconductive THz array structures, consisting of a thin LT-GaAs active region transferred to an insulating substrate using a wafer-scale bonding process. The electrically insulating, transparent substrate reduces the parasitic currents in the devices, allowing peak THz-fields as high as 120 kV cm−1 to be generated over a bandwidth >5 THz. These results are achieved using lower pulse energies than demanded by conventional photoconductive arrays and other popular methods of generating high-field THz radiation. Two device sizes are fully characterised and the emission properties are compared to generation by optical rectification in ZnTe. The device can be operated in an optically saturated regime in order to suppress laser noise

High-Speed Modulation of a Terahertz Quantum Cascade Laser by Coherent Acoustic Phonon Pulses

The fast modulation of lasers is a fundamental requirement for applications in optical communications, high-resolution spectroscopy and metrology. In the terahertz-frequency range, the quantum-cascade laser (QCL) is a high-power source with the potential for high-frequency modulation. However, conventional electronic modulation is limited fundamentally by parasitic device impedance, and so alternative physical processes must be exploited to modulate the QCL gain on ultrafast timescales. Here, we demonstrate an alternative mechanism to modulate the emission from a QCL device, whereby optically-generated acoustic phonon pulses are used to perturb the QCL bandstructure, enabling fast amplitude modulation that can be controlled using the QCL drive current or strain pulse amplitude, to a maximum modulation depth of 6% in our experiment. We show that this modulation can be explained using perturbation theory analysis. While the modulation rise-time was limited to ~800 ps by our measurement system, theoretical considerations suggest considerably faster modulation could be possible

A qualitative study of mothers’ perceptions of weaning and the use of commercial infant food in the United Kingdom

Background: Commercially produced infant food has a different taste profile and nutritional content to homemade baby food and its consumption is now very widespread. This change in early food experience may lead to a reduced dietary variety and a decreased microbial load exposure.Objective: The purpose of this study was to gain insight into parental perceptions of complementary feeding, specifically opinions of commercially produced baby food, using qualitative research methods. Methods: Four focus group discussions took place (n = 24), with mothers of infants aged 4-7 months. Half of participants were first time mothers and a third had experience weaning infants with symptoms of cows' milk allergy. Participants were prompted with questions about complementary feeding and shown several different products to stimulate discussion. Results: Thematic analysis of focus groups indicated that three distinctive groups of mothers exist;

High-speed modulation of a terahertz-frequency quantum-cascade laser using coherent acoustic phonon pulses

We demonstrate a new method for high-speed modulation of the electron transport and photon generation within a terahertz-frequency quantum-cascade laser (THz QCL). An amplified femtosecond laser is used to generate coherent acoustic-phonon pulses, which are injected into the device, resulting in an electronic bandstructure perturbation, with ~1-ns rise-time. The corresponding change in optical gain allows up to ~6% amplitude modulation, with results explained accurately using a perturbation-theory model

The experience of linking Victorian emergency medical service trauma data

<p>Abstract</p> <p>Background</p> <p>The linking of a large Emergency Medical Service (EMS) dataset with the Victorian Department of Human Services (DHS) hospital datasets and Victorian State Trauma Outcome Registry and Monitoring (VSTORM) dataset to determine patient outcomes has not previously been undertaken in Victoria. The objective of this study was to identify the linkage rate of a large EMS trauma dataset with the Department of Human Services hospital datasets and VSTORM dataset.</p> <p>Methods</p> <p>The linking of an EMS trauma dataset to the hospital datasets utilised deterministic and probabilistic matching. The linking of three EMS trauma datasets to the VSTORM dataset utilised deterministic, probabilistic and manual matching.</p> <p>Results</p> <p>There were 66.7% of patients from the EMS dataset located in the VEMD. There were 96% of patients located in the VAED who were defined in the VEMD as being admitted to hospital. 3.7% of patients located in the VAED could not be found in the VEMD due to hospitals not reporting to the VEMD. For the EMS datasets, there was a 146% increase in successful links with the trauma profile dataset, a 221% increase in successful links with the mechanism of injury only dataset, and a 46% increase with sudden deterioration dataset, to VSTORM when using manual compared to deterministic matching.</p> <p>Conclusion</p> <p>This study has demonstrated that EMS data can be successfully linked to other health related datasets using deterministic and probabilistic matching with varying levels of success. The quality of EMS data needs to be improved to ensure better linkage success rates with other health related datasets.</p

Indexes to Find the Optimal Number of Clusters in a Hierarchical Clustering

Clustering analysis is one of the most commonly used techniques for uncovering patterns in data mining. Most clustering methods require establishing the number of clusters beforehand. However, due to the size of the data currently used, predicting that value is at a high computational cost task in most cases. In this article, we present a clustering technique that avoids this requirement, using hierarchical clustering. There are many examples of this procedure in the literature, most of them focusing on the dissociative or descending subtype, while in this article we cover the agglomerative or ascending subtype. Being more expensive in computational and temporal cost, it nevertheless allows us to obtain very valuable information, regarding elements membership to clusters and their groupings, that is to say, their dendrogram. Finally, several sets of data have been used, varying their dimensionality. For each of them, we provide the calculations of internal validation indexes to test the algorithm developed, studying which of them provides better results to obtain the best possible clustering

Modulation of the THz Emission by a Quantum Cascade Laser using Coherent Acoustic Phonon Pulses

We use laser-generated coherent acoustic phonon (strain) pulses to modulate the electronic transport and THz emission of a 2.6 THz Ga(Al)As quantum cascade laser. The modulation amplitude is of the order of a few % and the rise time, limited by the measurement system response, is less than 1 nanosecond