Arrecifes de coral como sistemas complejos: degradación y perspectivas de recuperación

The present century is witness to unprecedented levels of coral reef degradation worldwide. Current understanding based on traditional ideas is unlikely to capture adequately the dynamics of phenomena accompanying this trend. In this regard, the ideas of complexity are reviewed. Some applications to coral reefs as complex systems have already been discussed in the literature although further progress is warranted as the search for new and more effective management tools continues, and the direction towards more holistic, integrative and large scale approaches gains wider acceptance. We distinguish between the concepts of robustness and resilience in the face of disturbance, highlight the various mechanisms that foster these stability properties and provide some coral reef examples. We identify some of the driving forces behind succession that are critical for community assembly and possible reef recovery. Finally, we consider how self-organization arises out of apparently random and chaotic processes and interactions to exhibit certain regularities and patterns especially when moving up on the scale of space and/or time.El presente siglo es testigo de niveles de degradación sin precedentes de los arrecifes de coral. El conocimiento previo basado en estudios tradicionales no es capaz de entender la dinámica de esta tendencia de degradación. En este contexto, las ideas sobre la complejidad de los arrecifes se revisa en este trabajo. Algunas aproximaciones sobre la complejidad de los arrecifes ya han sido mencionados en la literatura, pero se necesita progresar más y ser más efectivos en la línea de enfoques más holísticos, integrativos y de mayor escala que son, al mismo tiempo, los más aceptados actualmente. En el trabajo distinguimos conceptos de robustez y de resilencia dentro del marco de las perturbaciones, hacemos énfasiz en los mecanismos que confieren propiedad de estabilidad y planteamos ejemplos en los arrecifes de coral. Identificamos algunas fuerzas que gobiernan aspectos críticos para los arrecifes como es la sucesión ecológica y la posible recuperación de los mismos. Finalmente, consideramos cómo los procesos de auto-organización surgen de procesos aparentemente caóticos o al azar y de interacciones que permiten mostrar ciertas regularidades y pautas, especialmente cuando se aumenta la escala espacio temporal de observación.

Surface Acoustic Wave Bidirectional Filter Synthesis and Analysis

Surface Acoustic Wave (SAW) devices are manufactured using standard metallization and photolithographic techniques that have been established by the semiconductor industry. The facilities in the newly developed Microelectronics laboratory at the University of Central Florida will be utilized in the fabrication of a SAW device. This thesis will outline the complete procedure beginning with the initial design from given specifications, up to mask generation, fabricating and testing of the device. This will serve to calibrate the fabrication process for future work in SAW device and semiconductor fabrication. The models that are used in the SAWCAD design software will be verified by comparing the theoretical and experimental results

Ice nucleation at the contact line triggered by transient electrowetting fields

Supercooled water is found to have a significantly enhanced freezing temperature during transient electrowetting with electric fields of order 1 V/μm. High speed imaging reveals that the nucleation occurs randomly at the three-phase contact line (droplet perimeter) and can occur at multiple points during one freezing event. Possible nucleation mechanisms are explored by testing various substrate geometries and materials. Results demonstrate that electric field alone has no detectable effect on ice nucleation, but the moving boundary of the droplet on the substrate due to electrowetting is associated with the triggering of nucleation at a much higher temperature

Determining how polymer-bubble interactions impact algal separation using the novel "Posi"-dissolved air flotation process

The novel dissolved air flotation (DAF) process that uses hydrophobically-modified polymers (HMPs) to generate positively charged bubbles (PosiDAF) has been shown to separate negatively charged algal cells without the need for coagulation-flocculation. Previous research has been limited to HMPs of poly(N,N-dimethylaminoethyl methacrylate) (PDMAEMA) and, while they were effective at bench-scale, performance at pilot-scale was better using commercial poly(N,N-diallyl-N,N-dimethylammonium chloride) (PDADMAC). Hence, the aim of this research was to compare the effectiveness of PDADMAC modified with aliphatic and aromatic moieties in comparison to previously tested PDMAEMA HMPs in respect to algal cell separation and minimisation of effluent polymer concentration, as well as defining the underlying polymer-bubble interaction mechanisms. Polymer-bubble adhesion properties were measured using atomic force microscopy (AFM) while polymer concentration was monitored via zeta potential and, where possible, assays using fluorescence spectroscopy. Both PDADMAC functionalised with a fluorinated aromatic group (PDADMAC-BCF) and PDMAEMA modified with 1-bromodecane respectively, gave effective cell separation, while the treated effluent zeta potential values at maximum cell removal were lower than the other polymers trialled. The effluent polymer concentration when using PDADMAC-BCF was four times lower in comparison to another aromatically modified PDADMAC polymer. AFM studies indicated that, in contrast to the PDMAEMA-based polymers, the PDADMAC-based polymers did not adsorb closely to the bubble surface. The different polymer-bubble interactions indicate that separation mechanisms will also vary, potentially leading to differences in process effectiveness when explored at pilot scale

Influenza Excess Mortality from 1950–2000 in Tropical Singapore

10.1371/journal.pone.0008096PLoS ONE412

Replication and Meta-analysis of the Association between BDNF Val66Met Polymorphism and Cognitive Impairment in Patients Receiving Chemotherapy.

Cancer-related cognitive impairment (CRCI) adversely affects cancer patients. We had previously demonstrated that the BDNF Val66Met genetic polymorphism is associated with lower odds of subjective CRCI in the multitasking and verbal ability domains among breast cancer patients receiving chemotherapy. To further assess our previous findings, we evaluated the association of BDNF Val66Met polymorphism with subjective and objective CRCI in a temporally separate cohort of patients and pooled findings from both the original (n = 145) and current (n = 193) cohorts in a meta-analysis. Subjective CRCI was assessed using FACT-Cog. Objective CRCI was evaluated using computerized neuropsychological tests. Genotyping was carried out using Sanger sequencing. The association of BDNF Val66Met genotypes and CRCI was examined with logistic regression. A fixed-effect meta-analysis was conducted using the inverse variance method. In the meta-analysis (n = 338), significantly lower odds of CRCI were associated with Met allele carriers based on the global FACT-Cog score (OR = 0.52, 95% CI 0.29-0.94). Furthermore, Met allele carriers were at lower odds of developing impairment in the domains of memory (OR = 0.34, 95% CI: 0.17-0.70), multitasking (OR = 0.33, 95% CI: 0.18-0.59), and verbal ability (OR = 0.46, 95% CI: 0.24-0.88). Consistent with the previous study, lower odds of subjective CRCI among patients with the BDNF Met allele was observed after adjusting for potential confounders in the multitasking (OR = 0.30, 95% CI: 0.14-0.67) domain. In conclusion, carriers of the BDNF Met allele were protected against global subjective CRCI, particularly in the domains of memory, multitasking, and verbal ability. Our findings further contribute to the understanding of CRCI pathophysiology

Factors influencing AIS effectiveness among manufacturing SMEs: Evidence from Malaysia

This study examines accounting information systems (AIS) effectiveness and its influence factors in the specific context of small and medium manufacturing enterprises (SMEs) in Malaysia. The proposed model examines the impact of AIS sophistication, manager participation in AIS implementation, manager AIS knowledge, manager accounting knowledge, and effectiveness of external experts such as vendors, consultants, government agencies, and accounting firms on AIS effectiveness. We included 232 SMEs registered with the Federation of Malaysian Manufacturers (FMM) in testing the model. The results show that manager accounting knowledge, and the effectiveness of vendors and accounting firms significantly contributed to AIS effectiveness. Overall, this study suggests that managers of SMEs need to acquire sufficient accounting knowledge to better understand business information requirements. Second, SMEs should engage qualified vendors who have experience and understand unique characteristics of SME to overcome their lack of AIS knowledge. SMEs should also exploit their good relationship with accounting firms to help them implement effective AIS. Finally, it is important for SMEs to learn from AIS implementation so that opportunities can be recognized and priority can be given to those initiatives that support their information needs

Who responds? An examination of response rates to a national postal survey of Aboriginal and Torres Strait Islander adults, 2018-2019

Background Evidence on the effectiveness of postal recruitment methods for Indigenous peoples is lacking. Mayi Kuwayu, the National Study of Aboriginal and Torres Strait Islander Wellbeing, uses multi-staged sampling. We aimed to test postal surveys as a primary recruitment method, analysing preliminary response rate data to inform the Study’s ongoing sampling approach. Methods Twenty thousand adults aged ≥16 years were sampled from Aboriginal and Torres Strait Islander people enrolled in the Medicare Australia Enrolment Database. We calculated response rates at 4 and 15 weeks, overall and by age group, gender, state/territory and remoteness. Results The overall response rate was 2.3% (n = 456/20000). Highest response rates were observed among males and females ≥50 years from major cities (6.0, 95%CI 4.4–7.9 and 5.5%, 4.1–7.2, respectively) and regional areas (6.0%, 4.6–7.6 and 6.2%, 4.9–7.7, respectively). Younger age groups and remote areas had lower response rates; all remote age groups < 50 years had a response rate ≤ 0.6%. While most participants responded on the paper surveys, online responses were more common among younger age groups and, respondents with higher education levels and whose first language was not English. Conclusion Using a postal survey, we observed response rates of ≥5.5% among older Aboriginal and Torres Strait Islander adults in major cities and regional areas; response rates were lower in other groups. A two-stage postal distribution approach provided an opportunity to adapt sampling approaches to different demographic groups. Based on initial response rates, the sampling strategy was revised to send postal surveys to groups with higher response rates groups and focus field recruitment strategies on low response groups.on low response groups.The Mayi Kuwayu Study development and preliminary postal distribution was supported by the Lowitja Institute (ref: 1344). AW is supported by an Australian Government Research Training Program Scholarship and an ANU Dean’s Award Scholarship. KT is supported by the Lowitja Institute (ref: 1344

Repositioning for pressure injury prevention in adults

BACKGROUND: A pressure injury (PI), also referred to as a 'pressure ulcer', or 'bedsore', is an area of localised tissue damage caused by unrelieved pressure, friction, or shearing on any part of the body. Immobility is a major risk factor and manual repositioning a common prevention strategy. This is an update of a review first published in 2014. OBJECTIVES: To assess the clinical and cost effectiveness of repositioning regimens(i.e. repositioning schedules and patient positions) on the prevention of PI in adults regardless of risk in any setting. SEARCH METHODS: We searched the Cochrane Wounds Specialised Register, the Cochrane Central Register of Controlled Trials (CENTRAL), Ovid MEDLINE, Ovid Embase, and EBSCO CINAHL Plus on 12 February 2019. We also searched clinical trials registries for ongoing and unpublished studies, and scanned the reference lists of included studies as well as reviews, meta-analyses, and health technology reports to identify additional studies. There were no restrictions with respect to language, date of publication, or study setting. SELECTION CRITERIA: Randomised controlled trials (RCTs), including cluster-randomised trials (c-RCTs), published or unpublished, that assessed the effects of any repositioning schedule or different patient positions and measured PI incidence in adults in any setting. DATA COLLECTION AND ANALYSIS: Three review authors independently performed study selection, 'Risk of bias' assessment, and data extraction. We assessed the certainty of the evidence using GRADE. MAIN RESULTS: We identified five additional trials and one economic substudy in this update, resulting in the inclusion of a total of eight trials involving 3941 participants from acute and long-term care settings and two economic substudies in the review. Six studies reported the proportion of participants developing PI of any stage. Two of the eight trials reported within-trial cost evaluations. Follow-up periods were short (24 hours to 21 days). All studies were at high risk of bias. Funding sources were reported in five trials. Primary outcomes: proportion of new PI of any stage Repositioning frequencies: three trials compared different repositioning frequencies We pooled data from three trials (1074 participants) comparing 2-hourly with 4-hourly repositioning frequencies (fixed-effect; I² = 45%; pooled risk ratio (RR) 1.06, 95% confidence interval (CI) 0.80 to 1.41). It is uncertain whether 2-hourly repositioning compared with 4-hourly repositioning used in conjunction with any support surface increases or decreases the incidence of PI. The certainty of the evidence is very low due to high risk of bias, downgraded twice for risk of bias, and once for imprecision. One of these trials had three arms (967 participants) comparing 2-hourly, 3-hourly, and 4-hourly repositioning regimens on high-density mattresses; data for one comparison was included in the pooled analysis. Another comparison was based on 2-hourly versus 3-hourly repositioning. The RR for PI incidence was 4.06 (95% CI 0.87 to 18.98). The third study comparison was based on 3-hourly versus 4-hourly repositioning (RR 0.20, 95% CI 0.04 to 0.92). The certainty of the evidence is low due to risk of bias and imprecision. In one c-RCT, 262 participants in 32 ward clusters were randomised between 2-hourly and 3-hourly repositioning on standard mattresses and 4-hourly and 6-hourly repositioning on viscoelastic mattresses. The RR for PI with 2-hourly repositioning compared with 3-hourly repositioning on standard mattress is imprecise (RR 0.90, 95% CI 0.69 to 1.16; very low-certainty evidence). The CI for PI include both a large reduction and no difference for the comparison of 4-hourly and 6-hourly repositioning on viscoelastic foam (RR 0.73, 95% CI 0.53 to 1.02). The certainty of the evidence is very low, downgraded twice due to high risk of bias, and once for imprecision. Positioning regimens: four trials compared different tilt positions We pooled data from two trials (252 participants) that compared a 30° tilt with a 90° tilt (random-effects; I² = 69%). There was no clear difference in the incidence of stage 1 or 2 PI. The effect of tilt is uncertain because the certainty of evidence is very low (pooled RR 0.62, 95% CI 0.10 to 3.97), downgraded due to serious design limitations and very serious imprecision. One trial involving 120 participants compared 30° tilt and 45° tilt with 'usual care' and reported no occurrence of PI events (low certainty evidence). Another trial involving 116 ICU patients compared prone with the usual supine positioning for PI. Reporting was incomplete and this is low certainty evidence. Secondary outcomes No studies reported health-related quality of life utility scores, procedural pain, or patient satisfaction. Cost analysis Two included trials also performed economic analyses. A cost-minimisation analysis compared the costs of 3-hourly and 4-hourly repositioning with 2-hourly repositioning schedule amongst nursing home residents. The cost of repositioning was estimated at CAD 11.05 and CAD 16.74 less per resident per day for the 3-hourly or 4-hourly regimen, respectively, compared with the 2-hourly regimen. The estimates of economic benefit were driven mostly by the value of freed nursing time. The analysis assumed that 2-, 3-, or 4-hourly repositioning is associated with a similar incidence of PI, as no difference in incidence was observed. A second study compared the nursing time cost of 3-hourly repositioning using a 30° tilt with standard care (6-hourly repositioning with a 90° lateral rotation) amongst nursing home residents. The intervention was reported to be cost-saving compared with standard care (nursing time cost per patient EUR 206.60 versus EUR 253.10, incremental difference EUR -46.50, 95% CI EUR -1.25 to EUR -74.60). AUTHORS' CONCLUSIONS: Despite the addition of five trials, the results of this update are consistent with our earlier review, with the evidence judged to be of low or very low certainty. There remains a lack of robust evaluations of repositioning frequency and positioning for PI prevention and uncertainty about their effectiveness. Since all comparisons were underpowered, there is a high level of uncertainty in the evidence base. Given the limited data from economic evaluations, it remains unclear whether repositioning every three hours using the 30° tilt versus "usual care" (90° tilt) or repositioning 3-to-4-hourly versus 2-hourly is less costly relative to nursing time