1,203 research outputs found
Are artificial reefs surrogates of natural habitats for corals and fish in Dubai, United Arab Emirates?
Artificial reefs are often promoted as mitigating human impacts in coastal ecosystems and enhancing fisheries; however, evidence supporting their benefits is equivocal. Such structures must be compared with natural reefs in order to assess their performance, but past comparisons typically examined artificial structures that were too small, or were immature, relative to the natural reefs. We compared coral and fish communities on two large (\u3e400,000 m3) and mature (\u3e25 year) artificial reefs with six natural coral patches. Coral cover was higher on artificial reefs (50%) than in natural habitats (31%), but natural coral patches contained higher species richness (29 vs. 20) and coral diversity (HâČ = 2.3 vs. 1.8). Multivariate analyses indicated strong differences between coral communities in natural and artificial habitats. Fish communities were sampled seasonally for 1 year. Multivariate fish communities differed significantly among habitat types in the summer and fall, but converged in the winter and spring. Univariate analysis indicated that species richness and abundance were stable throughout the year on natural coral patches but increased significantly in the summer on artificial reefs compared with the winter and spring, explaining the multivariate changes in community structure. The increased summer abundance on artificial reefs was mainly due to adult immigration. Piscivores were much more abundant in the fall than in the winter or spring on artificial reefs, but had low and stable abundance throughout the year in natural habitats. It is likely that the decreased winter and spring abundance of fish on the artificial reefs resulted from both predation and emigration. These results indicate that large artificial reefs can support diverse and abundant coral and fish communities. However, these communities differ structurally and functionally from those in natural habitats, and they should not be considered as replacements for natural coral and fish communities. © Springer-Verlag 2009
Application of a single-objective, hybrid genetic algorithm approach to pharmacokinetic model building.
A limitation in traditional stepwise population pharmacokinetic model building is the difficulty in handling interactions between model components. To address this issue, a method was previously introduced which couples NONMEM parameter estimation and model fitness evaluation to a single-objective, hybrid genetic algorithm for global optimization of the model structure. In this study, the generalizability of this approach for pharmacokinetic model building is evaluated by comparing (1) correct and spurious covariate relationships in a simulated dataset resulting from automated stepwise covariate modeling, Lasso methods, and single-objective hybrid genetic algorithm approaches to covariate identification and (2) information criteria values, model structures, convergence, and model parameter values resulting from manual stepwise versus single-objective, hybrid genetic algorithm approaches to model building for seven compounds. Both manual stepwise and single-objective, hybrid genetic algorithm approaches to model building were applied, blinded to the results of the other approach, for selection of the compartment structure as well as inclusion and model form of inter-individual and inter-occasion variability, residual error, and covariates from a common set of model options. For the simulated dataset, stepwise covariate modeling identified three of four true covariates and two spurious covariates; Lasso identified two of four true and 0 spurious covariates; and the single-objective, hybrid genetic algorithm identified three of four true covariates and one spurious covariate. For the clinical datasets, the Akaike information criterion was a median of 22.3 points lower (range of 470.5 point decrease to 0.1 point decrease) for the best single-objective hybrid genetic-algorithm candidate model versus the final manual stepwise model: the Akaike information criterion was lower by greater than 10 points for four compounds and differed by less than 10 points for three compounds. The root mean squared error and absolute mean prediction error of the best single-objective hybrid genetic algorithm candidates were a median of 0.2 points higher (range of 38.9 point decrease to 27.3 point increase) and 0.02 points lower (range of 0.98 point decrease to 0.74 point increase), respectively, than that of the final stepwise models. In addition, the best single-objective, hybrid genetic algorithm candidate models had successful convergence and covariance steps for each compound, used the same compartment structure as the manual stepwise approach for 6 of 7 (86 %) compounds, and identified 54 % (7 of 13) of covariates included by the manual stepwise approach and 16 covariate relationships not included by manual stepwise models. The model parameter values between the final manual stepwise and best single-objective, hybrid genetic algorithm models differed by a median of 26.7 % (qâ = 4.9 % and qâ = 57.1 %). Finally, the single-objective, hybrid genetic algorithm approach was able to identify models capable of estimating absorption rate parameters for four compounds that the manual stepwise approach did not identify. The single-objective, hybrid genetic algorithm represents a general pharmacokinetic model building methodology whose ability to rapidly search the feasible solution space leads to nearly equivalent or superior model fits to pharmacokinetic data
Direct and indirect effects of interspecific competition in a highly partitioned guild of reef fishes
Competitive interactions and resource partitioning facilitate species coexistence in complex ecosystems. However, while pairwise interactions between ecologically similar species have been well studied, multiâspecies competitive networks have received less attention. When interference competition between two species results in partitioning of resources, this may have indirect consequences for other species distributed along the same resource gradient. Here, we tested whether interference competition between two territorial damselfish influenced the fineâscale species distributions of five other territorial damselfish in Kimbe Bay, Papua New Guinea. These species partition habitat across three reef zonesâthe flat, crest, and slope, with distinct patterns of distribution within these zones. We predicted the two species with similar distributions and microhabitat use, Pomacentrus adelus and Pomacentrus bankanensis, would display the greatest level of aggression toward one another. This was tested through an intruder experiment where stimulus fish were introduced into a resident's territory, which confirmed disproportionately high levels of interspecific aggression between these two species. We also predicted that the fineâscale differences in the distribution of each species were maintained through multiâspecies interference competition among neighboring species, with further indirect effects on species that did not directly interact. To test this, we conducted a largeâscale (22 Ă 10 m) experimental removal of the most abundant species, Po. adelus, and quantified the abundance and distribution of all territorial damselfish species for 6 months to a 25 cm resolution. The main direct competitor, Po. bankanensis, exhibited a marked increase in abundance and expanded its distribution (+1.33 m) to acquire the space previously occupied by Po. adelus. This competitive release triggered indirect effects on the distribution of other neighboring species further back on the reef flat, with Chrysiptera unimaculata moving into the zone formerly occupied by Po. bankanensis. This study indicates that the distinct distribution patterns among the reef crest species are linked to levels of interspecific agonistic behavior. We argue that the competitive release following the removal of a superior competitor resulted in both direct and indirect effects, with the immediate neighbor shifting into the newly available space, followed by successive shifts in species responding to the change in the distributions of their immediate neighbors
Systematic review of outcome measures of walking training using electromechanical and robotic devices in patients with stroke
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Massive open star clusters using the VVV survey, I: presentation of the data and description of the approach
Context. The ESO Public Survey âVISTA Variables in the VĂa LĂĄcteaâ (VVV) provides deep multi-epoch infrared observations for unprecedented 562 sq. degrees of the Galactic bulge, and adjacent regions of the disk. Aims. The VVV observations will foster the construction of a sample of Galactic star clusters with reliable and homogeneously derived physical parameters (e.g., age, distance, and mass, etc.). In this first paper in a series, the methodology employed to establish cluster parameters for the envisioned database are elaborated upon by analysing four known young open clusters: Danks 1, Danks 2, RCW 79, and DBS 132. The analysis offers a first glimpse of the information that can be gleaned from the VVV observations for clusters in the final database. Methods. Wide-field, deep JHKs VVV observations, combined with new infrared spectroscopy, are employed to constrain fundamental parameters for a subset of clusters. Results. Results are inferred from VVV near-infrared photometry and numerous low resolution spectra (typically more than 10 per cluster). The high quality of the spectra and the deep wideâfield VVV photometry enables us to precisely and independently determine the characteristics of the clusters studied, which we compare to previous determinations. An anomalous reddening law in the direction of the Danks clusters is found, specifically E(J â H)/E(H â Ks) = 2.20 ± 0.06, which exceeds published values for the inner Galaxy. The G305 star forming complex, which includes the Danks clusters, lies beyond the Sagittarius-Carina spiral arm and occupies the Centaurus arm. Finally, the first deep infrared colour-magnitude diagram of RCW 79 is presented, which reveals a sizeable pre-main sequence population. A list of candidate variable stars in G305 region is reported. Conclusions. This study demonstrates the strength of the dataset and methodology employed, and constitutes the first step of a broader study which shall include reliable parameters for a sizeable number of poorly characterised and/or newly discovered clusters.Fil: ChenĂ©, A.-N.. Universidad de ValparaĂso; ChileFil: Borissova, J.. Universidad de ValparaĂso; ChileFil: Clarke, J. R. A.. Universidad de ValparaĂso; ChileFil: Bonatto, C.. Universidade Federal do Rio Grande do Sul; BrasilFil: Majaess, D. J.. Saint Marys University; CanadĂĄFil: Moni Bidin, C.. Universidad de ConcepciĂłn; ChileFil: Sale, S. E.. Universidad de ValparaĂso; ChileFil: Mauro, F.. Universidad de ConcepciĂłn; ChileFil: Kurtev, R.. Universidad de ValparaĂso; ChileFil: Baume, Gustavo Luis. Universidad Nacional de La Plata. Facultad de Ciencias AstronĂłmicas y GeofĂsicas; Argentina. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Centro CientĂfico TecnolĂłgico Conicet - La Plata. Instituto de AstrofĂsica La Plata. Universidad Nacional de La Plata. Facultad de Ciencias AstronĂłmicas y GeofĂsicas. Instituto de AstrofĂsica La Plata; ArgentinaFil: Feinstein Baigorri, Carlos. Universidad Nacional de La Plata. Facultad de Ciencias AstronĂłmicas y GeofĂsicas; Argentina. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Centro CientĂfico TecnolĂłgico Conicet - La Plata. Instituto de AstrofĂsica La Plata. Universidad Nacional de La Plata. Facultad de Ciencias AstronĂłmicas y GeofĂsicas. Instituto de AstrofĂsica La Plata; ArgentinaFil: Ivanov, V. D.. European Southern Observatory; ChileFil: Geisler, Doug. Universidad de ConcepciĂłn; ChileFil: Catelan, M.. The Milky Way Millennium Nucleus; ChileFil: Minniti, Dante. The Milky Way Millennium Nucleus; ChileFil: Lucas, P.. University Of Hertfordshire; Reino UnidoFil: de Grijs, R.. Peking University; ChinaFil: Kumar, M. S. N.. Centro de Astrofisica da Universidade do Porto; Portuga
Caries-risk profiles in Italian adults using computer caries assessment system and ICDAS
Abstract: The aim of this study was to examine the correlation among socio-behavioral factors, caries status and caries risk, calculated through Cariogram, in an adult population. Four hundred eighty subjects (mean age 40.73, SE \ub1 0.33) randomly selected from the municipal electoral registry consented to participate in the survey. Subjects were examined, and the International Caries Detection Assessment System (ICDAS) index was registered. A highly structured questionnaire was submitted to investigate (1) personal data (i.e., age, gender, educational level, job categorization), (2) life-style behavior (i.e., smoking and dietary habits), and (3) oral health behavior (i.e., tooth brushing, use of fluoride and dental check-up frequency). An evaluation of the mutans streptococci concentration in saliva was also performed. Information on caries-related factors was entered into the Cariogram in order to generate an individual caries risk profile for each subject. Multinomial logistic regression was performed using Cariogram levels as the dependent variable. The possible correlated variables were analyzed using the principal component analysis (PCA). Considering ICDAS scores, 5.62% of the sample had at least an initial decay (ICDAS = 1-2), whereas 40.83% of the sample presented at least one moderate decay (ICDAS = 3-4) and 17.08% a severe decay (ICDAS = 5-6). Decay at ICDAS levels 5-6 and more than 5 missing teeth were statistically associated with Cariogram scores (OR = 2.36, 95%CI = 1.83\u20133.03 and OR = 1.43, 95%CI = 1.13\u20131.82, respectively). The results suggest that the Cariogram model was able to identify caries-related factors in an adult population. A direct association among the risk categories from Cariogram, the caries status and some socio-behavioral variables was verified
Design, development and deployment of a hand/wrist exoskeleton for home-based rehabilitation after stroke - SCRIPT project
YesChanges in world-wide population trends have provided new demands for new technologies in areas
such as care and rehabilitation. Recent developments in the the field of robotics for neurorehabilitation
have shown a range of evidence regarding usefulness of these technologies as a tool to augment
traditional physiotherapy. Part of the appeal for these technologies is the possibility to place a
rehabilitative tool in oneâs home, providing a chance for more frequent and accessible technologies
for empowering individuals to be in charge of their therapy.
Objective: this manuscript introduces the Supervised Care and Rehabilitation Involving Personal
Tele-robotics (SCRIPT) project. The main goal is to demonstrate design and development steps
involved in a complex intervention, while examining feasibility of using an instrumented orthotic
device for home-based rehabilitation after stroke.
Methods: the project uses a user-centred design methodology to develop a hand/wrist
rehabilitation device for home-based therapy after stroke. The patient benefits from a dedicated
user interface that allows them to receive feedback on exercise as well as communicating with
the health-care professional. The health-care professional is able to use a dedicated interface
to send/receive communications and remote-manage patientâs exercise routine using provided
performance benchmarks. Patients were involved in a feasibility study (n=23) and were instructed to
use the device and its interactive games for 180 min per week, around 30 min per day, for a period of
6 weeks, with a 2-months follow up. At the time of this study, only 12 of these patients have finished
their 6 weeks trial plus 2 months follow up evaluation.
Results: with the âuse feasibilityâ as objective, our results indicate 2 patients dropping out due
to technical difficulty or lack of personal interests to continue. Our frequency of use results indicate
that on average, patients used the SCRIPT1 device around 14 min of self-administered therapy a day.
The group average for the system usability scale was around 69% supporting system usability.
Conclusions: based on the preliminary results, it is evident that stroke patients were able to use the
system in their homes. An average of 14 min a day engagement mediated via three interactive games
is promising, given the chronic stage of stroke. During the 2nd year of the project, 6 additional games
with more functional relevance in their interaction have been designed to allow for a more variant context for interaction with the system, thus hoping to positively influence the exercise duration.
The system usability was tested and provided supporting evidence for this parameter. Additional
improvements to the system are planned based on formative feedback throughout the project and
during the evaluations. These include a new orthosis that allows a more active control of the amount
of assistance and resistance provided, thus aiming to provide a more challenging interaction.This work has been partially funded under Grant FP7-ICT-288698(SCRIPT) of the European Community Seventh Framework Programme
Effects of robot assisted gait training in progressive supranuclear palsy (PSP): a preliminary report
Multidimensional Results and Reflections on CAR-T: The Italian Evidence
The present study aims at defining the economic and organizational impacts of the introduction of chimeric antigen receptor T-cell therapy (CAR-T) in Italy, for the management of diffuse large B-cell lymphoma (DLBCL) patients in third-line therapy, defining the overall level of sustainability for both hospitals and the National Healthcare System (NHS). The analysis focused on CAR-T and Best Salvage Care (in the following BSC), assuming the Italian hospital and NHS perspectives, over a 36-month time horizon. Process mapping and activity-based costing methodologies were applied to collect the hospital costs related to the BSC and CAR-T pathways, including adverse event management. Anonymous administrative data on services provided (diagnostic and laboratory examinations, hospitalizations, outpatient procedures, and therapies) to 47 third-line patients with lymphoma, as well as any organizational investments required, were collected, in two different Italian Hospitals. The economic results showed that the BSC clinical pathway required less resources in comparison with CAR-T (excluding the cost related to the therapy) (BSC: 29,558.41 vs. CAR-T: EUR 71,220.84, â58.5%). The budget impact analysis depicts that the introduction of CAR-T would generate an increase in costs ranging from 15% to 23%, without considering treatment costs. The assessment of the organizational impact reveals that the introduction of CAR-T therapy would require additional investments equal to a minimum of EUR 15,500 to a maximum of EUR 100,897.49, from the hospital perspective. Results show new economic evidence for healthcare decision makers, to optimize the appropriateness of resource allocation. The present analysis suggests the need to introduce a specific reimbursement tariff, both at the hospital and at NHS levels, since no consensus exists, at least in the Italian setting, concerning the proper remuneration for the hospitals who guarantee this innovative pathway, assuming high risks related to timely management of adverse events
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