2,082 research outputs found

    Stick boundary conditions and rotational velocity auto-correlation functions for colloidal particles in a coarse-grained representation of the solvent

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    We show how to implement stick boundary conditions for a spherical colloid in a solvent that is coarse-grained by the method of stochastic rotation dynamics. This allows us to measure colloidal rotational velocity auto-correlation functions by direct computer simulation. We find quantitative agreement with Enskog theory for short times and with hydrodynamic mode-coupling theory for longer times. For aqueous colloidal suspensions, the Enskog contribution to the rotational friction is larger than the hydrodynamic one when the colloidal radius drops below 35nm.Comment: new version with some minor change

    Two complex orthogonal space-time codes for eight transmit antennas

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    Two new constructions of complex orthogonal space-time block codes of order 8 based on the theory of amicable orthogonal designs are presented and their performance compared with that of the standard code of order 8. These new codes are suitable for multi-modulation schemes where the performance can be sacrificed for a higher throughput

    Unitary Differential Space-Time-Frequency Codes for MB-OFDM UWB Wireless Communications

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    Psychosocial aspects of closed- and open-loop insulin delivery: closing the loop in adults with Type 1 diabetes in the home setting.

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    AIMS: To explore the psychosocial experiences of closed-loop technology and to compare ratings of closed- and open-loop technology for adults with Type 1 diabetes taking part in a randomized crossover study. METHODS: Adults (aged > 18 years) on insulin pump therapy were recruited to receive a first phase of either real-time continuous glucose monitoring with overnight closed-loop or real-time continuous glucose monitoring alone (open-loop) followed by a second phase of the alternative treatment in random order, at home for 4 weeks, unsupervised. Participants were invited to share their views in semi-structured interviews. The impact of the closed-loop technology, positive and negative aspects of living with the device overnight, along with the hopes and anxieties of the participants, were explored. RESULTS: The participants in the trial were 24 adults with a mean (sd) age of 43 (12) years, of whom 54% were men. The mean (range) interview duration was 26 (12-46) min. Content and thematic analysis showed the following key positive themes: improved blood glucose control (n = 16); reassurance/reduced worry (n = 16); improved overnight control leading to improved daily functioning and diabetes control (n = 16); and improved sleep (n = 8). The key negative themes were: technical difficulties (n = 24); intrusiveness of alarms (n = 13); and size of equipment (n = 7). Of the 24 participant, 20 would recommend the closed-loop technology. CONCLUSIONS: Closed-loop therapy has positive effects when it works in freeing participants from the demands of self-management. The downside was technical difficulties, particularly concerning the pump and 'connectivity', which it is hoped will improve. Future research should continue to explore the acceptability of the closed-loop system as a realistic therapy option, taking account of user concerns as new systems are designed. Failure to do this may reduce the eventual utility of new systems.Diabetes UKThis is the accepted manuscript. The final version is available at http://dx.doi.org/10.1111/dme.12706

    Mid-infrared frequency comb spanning an octave based on an Er fiber laser and difference-frequency generation

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    We describe a coherent mid-infrared continuum source with 700 cm-1 usable bandwidth, readily tuned within 600 - 2500 cm-1 (4 - 17 \mum) and thus covering much of the infrared "fingerprint" molecular vibration region. It is based on nonlinear frequency conversion in GaSe using a compact commercial 100-fs-pulsed Er fiber laser system providing two amplified near-infrared beams, one of them broadened by a nonlinear optical fiber. The resulting collimated mid-infrared continuum beam of 1 mW quasi-cw power represents a coherent infrared frequency comb with zero carrier-envelope phase, containing about 500,000 modes that are exact multiples of the pulse repetition rate of 40 MHz. The beam's diffraction-limited performance enables long-distance spectroscopic probing as well as maximal focusability for classical and ultraresolving near-field microscopies. Applications are foreseen also in studies of transient chemical phenomena even at ultrafast pump-probe scale, and in high-resolution gas spectroscopy for e.g. breath analysis.Comment: 8 pages, 2 figures revised version, added reference

    The geographical distribution and prevalence of Echinococcus multilocularis in animals in the European Union and adjacent countries : a systematic review and meta-analysis

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    Background This study aimed to provide a systematic review on the geographical distribution of Echinococcus multilocularis in definitive and intermediate hosts in the European Union (EU) and adjacent countries (AC). The relative importance of the different host species in the life-cycle of this parasite was highlighted and gaps in our knowledge regarding these hosts were identified. Methods Six databases were searched for primary research studies published from 1900 to 2015. From a total of 2,805 identified scientific papers, 244 publications were used for meta-analyses. Results Studies in 21 countries reported the presence of E. multilocularis in red foxes, with the following pooled prevalence (PP): low (≤ 1 %; Denmark, Slovenia and Sweden); medium (> 1 % to 10 %; Czech Republic, Estonia, France, Germany, Latvia, Lithuania, Poland, Slovakia, Liechtenstein and Switzerland). Studies from Finland, Ireland, the United Kingdom and Norway reported the absence of E. multilocularis in red foxes. However, E. multilocularis was detected in Arctic foxes from the Arctic Archipelago of Svalbard in Norway. Conclusions Raccoon dogs (PP 2.2 %), golden jackals (PP 4.7 %) and wolves (PP 1.4 %) showed a higher E. multilocularis PP than dogs (PP 0.3 %) and cats (PP 0.5 %). High E. multilocularis PP in raccoon dogs and golden jackals correlated with high PP in foxes. For intermediate hosts (IHs), muskrats (PP 4.2 %) and arvicolids (PP 6.0 %) showed similar E. multilocularis PP as sylvatic definitive hosts (DHs), excluding foxes. Nutrias (PP 1.0 %) and murids (PP 1.1 %) could play a role in the life-cycle of E. multilocularis in areas with medium to high PP in red foxes. In areas with low PP in foxes, no other DH was found infected with E. multilocularis. When fox E. multilocularis PP was >3 %, raccoon dogs and golden jackals could play a similar role as foxes. In areas with high E. multilocularis fox PP, the wolf emerged as a potentially important DH. Dogs and cats could be irrelevant in the life-cycle of the parasite in Europe, although dogs could be important for parasite introduction into non-endemic areas. Muskrats and arvicolids are important IHs. Swine, insectivores, murids and nutrias seem to play a minor or no role in the life-cycle of the parasite within the EU and ACs

    An interactive health communication application for supporting parents managing childhood long-term conditions: outcomes of a randomized controlled feasibility trial

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    Background: Families living with chronic or long-term conditions such as chronic kidney disease (CKD), stages 3-5, face multiple challenges and respond to these challenges in various ways. Some families adapt well while others struggle, and family response to a condition is closely related to outcome. With families and professionals, we developed a novel condition-specific interactive health communication app to improve parents’ management ability—the online parent information and support (OPIS) program. OPIS consists of a comprehensive mix of clinical caregiving and psychosocial information and support. Objective: The purpose of this study was to (1) assess feasibility of a future full-scale randomized controlled trial (RCT) of OPIS in terms of recruitment and retention, data collection procedures, and psychometric performance of the study measures in the target population, and (2) investigate trends in change in outcome measures in a small-scale RCT in parents of children with CKD stages 3-5. Methods: Parents were recruited from a pediatric nephrology clinic and randomly assigned to one of two treatment groups: usual support for home-based clinical caregiving (control) or usual support plus password-protected access to OPIS for 20 weeks (intervention). Both groups completed study measures at study entry and exit. We assessed feasibility descriptively in terms of recruitment and retention rates overall; assessed recruitment, retention, and uptake of the intervention between groups; and compared family condition management, empowerment to deliver care, and fathers’ involvement between groups. Results: We recruited 55 parents of 39 children (42% of eligible families). Of those, about three-quarters of intervention group parents (19/26, 73%) and control group parents (22/29, 76%) were retained through completion of 20-week data collection. The overall retention rate was 41/55 (75%). The 41 parents completing the trial were asked to respond to the same 10 questionnaire scales at both baseline and 20 weeks later; 10 scores were missing at baseline and nine were missing at 20 weeks. Site user statistics provided evidence that all intervention group parents accessed OPIS. Analysis found that intervention group parents showed a greater improvement in perceived competence to manage their child’s condition compared to control group parents: adjusted mean Family Management Measure (FaMM) Condition Management Ability Scale intervention group 44.5 versus control group 41.9, difference 2.6, 95% CI -1.6 to 6.7. Differences between the groups in the FaMM Family Life Difficulty Scale (39.9 vs 36.3, difference 3.7, 95% CI -4.9 to 12.2) appeared to agree with a qualitative observation that OPIS helped parents achieve understanding and maintain awareness of the impact of their child’s condition. Conclusions: A full-scale RCT of the effectiveness of OPIS is feasible. OPIS has the potential to beneficially affect self-reported outcomes, including parents’ perceived competence to manage home-based clinical care for children with CKD stage 3-5. Our design and methodology can be transferred to the management of other childhood conditions. Trial Registration: International Standard Randomized Controlled Trial Number (ISRCTN): 84283190; http://www.controlled-trials.com/ISRCTN84283190 (Archived by WebCite at http://www.webcitation.org/6TuPdrXTF)

    The use of mesh in acute hernia: frequency and outcome in 99 cases

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    Background: Incarceration of inguinal, umbilical and cicatricial hernias is a frequent problem. However, little is known about the relationship between the use of mesh and outcome after surgery. The goal of this study was to describe the relationship between the use of mesh in incarcerated hernia and the clinical outcome. Patients and methods: Correspondence, operation reports and patient files between January 1995 and December 2005 of patients presented at one academic and one teaching hospital in Rotterdam were searched for the following keywords: incarceration, strangulation and hernia. The patient characteristics, clinical presentation, pre-operative findings and clinical course were scored and analysed. Results: A total of 203 patients could be identified: 76 inguinal, 52 umbilical, 39 incisional, 14 epigastric, 14 femoral, five trocar and three spigelian hernias. In the statistical analysis, epigastric, femoral, trocar and spigelian hernias were pooled, due to their small group sizes. One patient was excluded from the analysis because the hernia was not corrected during operation. In total, 99 hernias were repaired using mesh versus 103 primary suture repairs. Twenty-five wound infections were registered (12.3%). One mesh was removed during a reintervention for anastomotic leakage, although no signs of wound infection were present. Nine patients died, none of them due to wound-related problems [one cardiovascular, one ruptured aneurysm, two anastomotic leakage, two sepsis e causa incognita (e.c.i.), three pulmonary complications]. Univariate analysis showed that female patients (P = 0.007), adipose patients (P = 0.016), patients with an umbilical hernia (P = 0.01) and patients who underwent a bowel resection (P = 0.015) had a significantly higher rate of wound infections. The type of repair (e.g. primary suture or mesh), use of antibiotic prophylaxis, gender, ASA class and age showed no significant relation with post-operative wound infection. After logistic regression analysis, only bowel resection (P = 0.020) showed a significant relation with post-operative wound infection. Conclusions: Wound infection rates are high after the correction of acute hernia, but clinical consequences are relatively low. Mesh correction of an acute hernia seems to be safe and should be considered in every incarcerated hernia
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