1,640 research outputs found
Spatio-temporal variation in the structure of a deep water Posidonia oceanica meadow assessed using non-destructive techniques
The Malta-Comino Channel (Maltese islands, central Mediterranean), supports
extensive meadows of the seagrass Posidonia oceanica that in some places
extend to a depth of around 43 m, which is rare for this seagrass. To assess
spatial and temporal variation in the state of the deeper parts of the P. oceanica
meadow with time, data on the structural characteristics of the seagrass meadow
at its lower bathymetric limit were collected during the summers of 2001,
2003 and 2004 from four stations (two stations within each of two sites)
located at a similar depth, over a spatial extent of 500 m. Shoot density was
estimated in situ, while data on plant architecture (number of leaves, mean leaf
length, and epiphyte load) were successfully obtained using an underwater photographic
technique that was specifically designed to avoid destructive sampling
of the seagrass. Results indicated that P. oceanica shoot density was lower than
that recorded from the same meadow during a study undertaken in 1995; the
observed decrease was attributed to the activities of an offshore aquaculture
farm that operated during the period 1995–2000 in the vicinity of the meadow.
ANOVA indicated significant spatial and temporal variations in meadow structural
attributes at both sites during the 3-year study; for example, shoot density
values increased overall with time at site A; a indication of potential recovery
of the meadow following cessation of the aquaculture operations. Lower shoot
density values recorded from site B (compared with site A) were attributed to
higher epiphyte loads on the seagrass, relative to those at site A. The findings,
which include new data on the structural characteristics of P. oceanica occurring
at depths >40 m, are discussed with reference to the use of the nondestructive
photographic technique to monitor the state of health of deep water
seagrass meadows.peer-reviewe
Baseline marine benthic surveys in the Maltese Islands (Central Mediterranean)
Extract from: MEDCOAST 97 : Proceedings of the Third International Conference on the Mediterranean Coastal Environment, Qawra, Malta / E. Ozhan (editor), (1997)During the period 1991 to 1997, extensive baseline studies of the submarine
geomorphology, infralittoral habitats, macrobenthic assemblages, and demersal fish
fauna, were carried out in 14 different sites around the Maltese Islands, using
conventional SCUBA diving techniques. These were made as part of assessments of the
environmental impact of existing or proposed projects, or in order to produce an inventory
of coastal resources. In total, these surveys covered a sea-bed area of ca. 7.55Km² and
a coastline length of ca 24 km, and represent the most extensive biological surveys
of the marine environment carried out to date in the Maltese Islands. The results of these
surveys have been presented as maps showing the type, location, and spatial extent of
these physical and biological features. The Peres & Picard (1964) scheme, as adapted
by Pen~s (1967; 1982) was used to classify and characterize the benthic assemblages
recorded during the surveys.
Our results show that, in tenus of spatial extent, the most important
macrobenthic assemblages are the communities of photophilic 'algae on hard substrata,
meadows of the sea-grass Posidonia oceanica and communities of bare well-sorted
sand. For all these, many subtypes and facies exist, depending on the light intensity,
hydrodynamic conditions, microtopography, sediment granulometry and other edaphic
factors, and anthropic influences, including pollution.
Other assemblages with a limited spatial distribution include meadows of the
sea-grass (vmodocea nodosa and of the Lessepsian immigrant Halophila stipu/acea on
sandy bottoms, the assemblages of boulder fields which are complexes of photophilic
and sciaphilic communities, and those of marine caves. Our maps are supplemented by
descriptions of the different habitats and macrobenthjc assemblages, species lists, and
semi-quantitative data on percentage cover for the dominant macroalgae, shoot density
counts for sea-grass meadows, and population density counts for the main macrofaunal
species.
These maps and data-sets are intended to be used (i) for assessing the status of
habitats, species assemblages, and individual species, around the Maltese Islands in
order to recommend appropriate measures for their conservation, including inclusion in
red data lists; (ii) for designation of marine protected areas; and (iii) as baselines against
which future monitoring studies and surveys can be compared.peer-reviewe
Towards integrated coastal zone management, with a special emphasis on the Mediterranean Sea: Introduction
Recommended from our members
A whole-health-economy approach to antimicrobial stewardship: Analysis of current models and future direction.
Antimicrobial stewardship (AMS) strategies are widely implemented in single healthcare sectors and organisations; however, the extent and impact of integrated AMS initiatives across the whole health economy are unknown.
Assessing degree of integration of AMS across the whole health economy and its impact is essential if we are to achieve a ‘One Health’ approach to addressing antimicrobial resistance (AMR), and therefore we searched systematically for and analysed published examples of integrated AMS initiatives to address this gap.
Application of a system-level framework to analyse integration of AMS initiatives across and within healthcare sectors shows that integration is emerging but needs strengthening.
Findings from a small number of evaluations in high-income countries suggest that antimicrobial prescribing and healthcare-associated infections can be reduced using a multisectoral integrated AMS approach.
More robust research designs to evaluate and understand the impact of multisectoral integrated AMS are needed, particularly with respect to differing health systems in different countries and local organisational contexts.
Our analysis highlights a number of challenges and ways forward for enhancing the delivery of AMS through an integrated approach
Evaluation of two street canyon air quality models using data from European cities
This paper presents a sensitivity analysis of the Operational Street Pollution Model
(OSPM) and an evaluation of OSPM and the Assessing the Environment Of
Locations In Urban Streets (AEOLTUS) model. Both models calculate airborne
concentrations of exhaust gases emitted by motor vehicles within street canyons.
They perform best when the street canyon aspect ratio is 1.0. OSPM and
AEOLIUS have been evaluated using data collected over a two-year period (1 994-
95) in Jagtvej, Copenhagen, Denmark. Further evaluation of the models was
carried out using data collected in Giittinger Strasse, Hannover (1994) and
Schildhom Strasse, Berlin (1995), both in Germany. In all cases, model runs were
carried out for carbon monoxide (CO). In the case of OSPM, two sets of newly
proposed emission factors were used for the street canyons in Germany. In the
calculation of these factors, the urban driving patterns and variations in the
composition of the vehicle fleet according to the engine capacity were assumed as
the most appropriate for the cases considered. Furthermore, parameters such as
engine operating temperature and the use of catalytic converter were taken into
account. Scatter plots of modelled against measured CO concentration yielded an
average regression coefficient of 0.90 for the street canyons considered. With the
newly proposed emission factors for Germany a lower regression coefficient was
obtained. From similar scatter plots, the AEOLIUS model gave a regression
coefficient of 0.86 for Jagtvej in 1994 and 0.78 for 1995. For Gottinger and
Schildhorn Strasse, the regression coefficient obtained was 0.8 1.peer-reviewe
Clinical and financial consequences of setting up an asthma clinic at St. Luke’s Hospital
The effects of setting up an asthma clinic were assessed in an audit study. A comparison was made between the quality and quantity of medication used by patients before and after attending the asthma clinic. The number and severity of exacerbations during a six month period before and a six month period after attending were also assessed. The cost of treatment before and after was also calculated. In 14% of patients, occupational factors, drugs or underlying lung disease were significant contributors to asthma. The number of acute episodes of severe asthma were reduced from 98 to 47, with hospital admissions falling from 26 to 1. Pulmonary function (%FEV1) improved in the group as a whole with the number of patients having their best FEV above 80% improving from 44 to 71. In spite of the expense of high cost drugs and the running costs of the clinic there were substantial savings largely from the reduced number of hospital admissions. The calculated annual cost fell from Lm 22,769 to Lm 10,654.peer-reviewe
EmoteControl: An interactive system for real-time control of emotional expression in music
Several computer systems have been designed for music emotion research that aim to identify how different structural or expressive cues of music influence the emotions conveyed by the music. However, most systems either operate offline by pre-rendering different variations of the music or operate in real-time but focus mostly on structural cues. We present a new interactive system called EmoteControl, which allows users to make changes to both structural and expressive cues (tempo, pitch, dynamics, articulation, brightness, and mode) of music in real-time. The purpose is to allow scholars to probe a variety of cues of emotional expression from non-expert participants who are unable to articulate or perform their expression of music in other ways. The benefits of the interactive system are particularly important in this topic as it offers a massive parameter space of emotion cues and levels for each emotion which is challenging to exhaustively explore without a dynamic system. A brief overview of previous work is given, followed by a detailed explanation of EmoteControl’s interface design and structure. A portable version of the system is also described, and specifications for the music inputted in the system are outlined. Several use-cases of the interface are discussed, and a formal interface evaluation study is reported. Results suggested that the elements controlling the cues were easy to use and understood by the users. The majority of users were satisfied with the way the system allowed them to express different emotions in music and found it a useful tool for research
integration of an organic rankine cycle and a photovoltaic unit for micro scale chp applications in the residential sector
Abstract The purpose of this work is to analyse the performance of a novel system for combined heat and power (CHP) generation in small-scale applications. The system is based on an Organic Rankine Cycle (ORC) fed with biomass and a photovoltaic (PV) unit. The ORC and PV sub-systems operate in parallel to produce the required electrical energy. A preliminary investigation is performed to define the proper size of the photovoltaic unit. Afterwards, the analysis is focused on the hybrid system and a comparison between the two configurations is carried out. This work demonstrates the potential for integrating biomass and solar energy resources: during daylight, solar radiation is significant and the ORC system can be switched off or operated at partial load. Furthermore, the adoption of biomass makes it possible to overcome the intermittency of solar resource, increase the self-consumed electrical energy, and produce thermal energy, thereby saving natural gas for heating purposes
Determination of serum zinc levels in normal Maltese adults by atomic absorption spectrophotometry
The importance of zinc as one of the essential trace elements in the living organisms is becoming increasingly recognised. In the process of carrying out measurements to establish normal reference values for our laboratory, it was noticed that the values being obtained, generally appeared to be higher than those published in the literature where similar techniques had been employed. It is important to gain further understanding of this metal in both health and disease as it appears that zinc is essential to an important variety of metabolic processes in man. We are unable to offer a satisfactory explanation for the difference in serum zinc levels in the two groups reported in this paper. Local water does not appear to have high zinc content and Maltese soil is known to be zinc deficient. It is known however that local farmers use a zinc containing fungicide (Zineb) on a large scale.peer-reviewe
LDPCA code construction for Slepian-Wolf coding
Error correcting codes used for Distributed Source Coding (DSC) generally assume a random distribution of errors. However, in certain DSC applications, prediction of the error distribution is possible and thus this assumption fails, resulting in a sub-optimal performance. This letter considers the construction of rate-adaptive Low-Density Parity-Check (LDPC) codes where the edges of the variable nodes receiving unreliable information are distributed evenly among all the check nodes. Simulation results show that the proposed codes can reduce the gap to the theoretical bounds by up to 56% compared to traditional codes.peer-reviewe
- …