A programmable microsystem using system-on-chip for real-time biotelemetry

A telemetry microsystem, including multiple sensors, integrated instrumentation and a wireless interface has been implemented. We have employed a methodology akin to that for System-on-Chip microelectronics to design an integrated circuit instrument containing several "intellectual property" blocks that will enable convenient reuse of modules in future projects. The present system was optimized for low-power and included mixed-signal sensor circuits, a programmable digital system, a feedback clock control loop and RF circuits integrated on a 5 mm × 5 mm silicon chip using a 0.6 μm, 3.3 V CMOS process. Undesirable signal coupling between circuit components has been investigated and current injection into sensitive instrumentation nodes was minimized by careful floor-planning. The chip, the sensors, a magnetic induction-based transmitter and two silver oxide cells were packaged into a 36 mm × 12 mm capsule format. A base station was built in order to retrieve the data from the microsystem in real-time. The base station was designed to be adaptive and timing tolerant since the microsystem design was simplified to reduce power consumption and size. The telemetry system was found to have a packet error rate of 10<sup>-</sup><sup>3</sup> using an asynchronous simplex link. Trials in animal carcasses were carried out to show that the transmitter was as effective as a conventional RF device whilst consuming less power

Symmetrized mean-field description of magnetic instabilities in k-(BEDT-TTF)_2Cu[N(CN)]_2 Y salts

We present a novel and convenient mean-field method, and apply it to study the metallic/antiferromagnetic interface of k-(BEDT-TTF)_2Cu[N(CN)]_2 Y organic superconductors (BEDT_TTF is bis-ethylen-dithio-tetrathiafulvalene, Y=Cl, Br). The method, which fully exploits the crystal symmetry, allows one to obtain the mean-field solution of the 2D Hubbard model for very large lattices, up to 6x10^5 sites, yielding a reliable description of the phase boundary in a wide region of the parameter space. The metal/antiferromagnet transtion appears to be second order, except for a narrow region of the parameter space, where the transition is very sharp and possibly first order. The cohexistence of metallic and antiferromagnetic properties is only observed for the transient state in the case of smooth second order transitions. The relevance of the present resaults to the complex experimental behavior of centrosymmetric k-phase BEDT-TTF salts is discussed.Comment: 9 pages in PS format, 7 figures (included in PS), 1 tabl

Further Evidence Suggestive of a Solar Influence on Nuclear Decay Rates

Recent analyses of nuclear decay data show evidence of variations suggestive of a solar influence. Analyses of datasets acquired at the Brookhaven National Laboratory (BNL) and at the Physikalisch-Technische Bundesanstalt (PTB) both show evidence of an annual periodicity and of periodicities with sidereal frequencies in the neighborhood of 12.25 year^{-1} (at a significance level that we have estimated to be 10^{-17}). It is notable that this implied rotation rate is lower than that attributed to the solar radiative zone, suggestive of a slowly rotating solar core. This leads us to hypothesize that there may be an "inner tachocline" separating the core from the radiative zone, analogous to the "outer tachocline" that separates the radiative zone from the convection zone. The Rieger periodicity (which has a period of about 154 days, corresponding to a frequency of 2.37 year^{-1}) may be attributed to an r-mode oscillation with spherical-harmonic indices l=3, m=1, located in the outer tachocline. This suggests that we may test the hypothesis of a solar influence on nuclear decay rates by searching BNL and PTB data for evidence of a "Rieger-like" r-mode oscillation, with l=3, m=1, in the inner tachocline. The appropriate search band for such an oscillation is estimated to be 2.00-2.28 year^{-1}. We find, in both datasets, strong evidence of a periodicity at 2.11 year^{-1}. We estimate that the probability of obtaining these results by chance is 10^{-12}.Comment: 12 pages, 6 figures, v2 has a color corrected Fig 6, a corrected reference, and a corrected typ

Birth asphyxia - Presenting the case for' A stitch in time'

Objectives. To. review the current birth asphyxia and subsequent cerebral palsy (CP) rates at a teaching hospital in a developing country, and to place these rates within the context of the current caesarean section (CS) rate. To determine the number of cases of birth asphyxia that are preventable.Design. Retrospective, descriptiv.e study.Setting. Neonatal nursery and intensive care unit, Johannesburg Hospital.Methods. Maternal and mionatal records were reviewed for 48 babies weighing less than 1 800 g born between 1 January and 31 December 1997 with birth asphyxia. Outcome after discharge was determined from the neonatal follow-up notes until 31 March 1998.Results. Mortality in the group of birth-asphyxiated babies was 12.5%. The birth asphyxia rate was 6/1 000 live births, and the CP rate in the study group was 1.15/1 000 live births. The CS rate for the group was 29%, with an overall CS rate at the hospital of 20.5%. In 22 cases (46%) the cause of birth asphyxia was considered to have been preventable.Conclusion. The cr rate is considerably higher than that quoted for developed  countries, and a significant number of cases of birth asphyxia in the study were  preventable. In the face of the high birth asphyxia and cr rates, the CS rate appears to be inappropriately Iow. The CS rate should be audited in the context of the birth asphyxia and cr rates

The effectiveness of multifactorial and multicomponent interventions for the prevention of falls for adults in hospital settings: a systematic review and meta-analysis.

The objective of this systematic review and meta-analysis was to evaluate the effectiveness of multicomponent and multifactorial interventions for reducing falls in adult in-patients. Falls are the most common cause of accidental injury in hospitals worldwide, resulting in high human and economic costs. In attempts to reduce the number of falls, a wide range of interventions have been employed, often in combination, either as a package (multicomponent) or tailored to the individual (multifactorial). There is a need to synthesise the findings from primary studies and assess which approach may be more effective. The systematic review included studies comprising adult inpatients aged 18 years and over from any hospital setting including elective, non-elective, day-case and secondary care. Randomized controlled trials (RCT), cluster-randomised trials, quasi-experimental controlled trials and historical controlled trials were included that presented sufficient information regarding the rate or number of falls. This effectiveness review was conducted in accordance with JBI methodology and was guided by an a priori protocol. A comprehensive 3-step search strategy was employed across 14 databases. Screening was conducted by two independent reviewers, and data was extracted using a bespoke data extraction tool designed for this review. Methodological quality was assessed using adapted versions of JBI critical appraisal checklists. Meta-analyses were conducted within a Bayesian framework to interpret results probabilistically and account for covariance in multiple sets of falls data reported in the same study. Effect sizes were calculated by comparing the rate or number of falls in the intervention group compared with usual care. Narrative syntheses were conducted on studies that met the inclusion criteria but did not provide sufficient data for inclusion in meta-analyses. A total of 9,637 records were obtained and following screening 24 studies were included in this review, 21 of which presented sufficient information to be included in meta-analyses. Most studies (n=16) comprised a weaker historical control design with 6 quasi-experimental and only 5 RCT studies. Multifactorial interventions were more common (n=18) than multicomponent (n=6), with the most frequent components including environmental adaptations and assistive aids (75% of studies). Meta-analyses provided evidence that both intervention types were effective at reducing the rate and risk of falls compared to usual care. Evidence was also obtained of greater reductions in rate and risk of falls with multicomponent interventions, however, analyses were potentially confounded by an association between intervention type and study design. Falls interventions routinely employed in hospitals can substantially reduce falls, however, no evidence was obtained in support of tailoring interventions to individual risk factors. Future high-quality RCTs are required that directly compare multicomponent and multifactorial interventions

Periventricular-intraventricular haemorrhage in low-birth-weight infants at Baragwanath Hospital

The prevalence of periventricular-intraventricular haemorrhage (PV-IVH) aInong very-low-birthweight infants at Baragwanath Hospital has not been well docwnented. In this prospective study, a total of 282 live-born infants with birth weights of 1 000 - 1 749 g were studied over a 41/2-month period. Every infant had at least one cranial ultrasound examination at 7 - 10 days of age, while one third of non-ventilated and all ventilated infants had ultrasound examinations on days 3, 7 and 14. Where possible, all infants had a follow-up ultrasound scan at 40 weeks' post-conceptional age. The overall prevalence of PV-IVH was 53% for infants weighing less than 1 500 g at birth and 52% for infants born at less than 35 weeks' gestation, but only 12% had either grade III or grade IV haemorrhages. The prevalence and severity of PV-IVH increased with both decreasing birth weight and decreasing gestational age and was also predicted by the need for active resuscitation at birth, mechanical ventilation and the development of pneumothorax. A total of 93% ofinfants without PV-IVH survived, but survival decreased with increasing grade of PV-IVH. Germinal matrix cysts were noted on follow-up in 55% of surviving infants with grade I PV-IVH. Very-low-birthweight infants at Baragwanath Hospital therefore seem to have a higher prevalence of PV-IVH when compared with reported figures, but this is due mainly to an increase in smaller haemorrhages

Localization of Quaternary slip rates in an active rift in 10(5) years: an example from central Greece constrained by U-234-Th-230 coral dates from uplifted paleoshorelines

Mapping, dating, and modeling of paleoshorelines uplifted in the footwall of the 1981 Gulf of Corinth earthquake fault, Greece (Ms 6.9–6.7), are used to assess its slip rate history relative to other normal faults in the area and study strain localization. The 234U-230Th coral ages from Cladocora caespitosa date uplifted shoreface sediments, and paleoshorelines from glacioeustatic sea level highstands at 76, (possibly) 100, 125, 175, 200, 216, 240, and 340 ka. Uplifted Quaternary and Holocene paleoshorelines decrease in elevation toward the western tip of the fault, exhibiting larger tilt angles with age, showing that uplift is due to progressive fault slip. Since 125 ka, uplift rates varied from 0.25 to 0.52 mm/yr over a distance of 5 km away from the fault tip. Tilting was also occurring prior to 125 ka, but uplift rates were lower because the 125 ka paleoshoreline is at 77% of the elevation of the 240 ka paleoshoreline despite being nearly half its age. Comparison of paleoshoreline elevations and sedimentology with the Quaternary sea level curve shows that slip rates increased by a factor of 3.2 ± 0.2 at 175 ± 75 ka, synchronous with cessation of activity on a neighboring normal fault at 382–112 ka. We suggest that the rapid localization of up to 10–15 mm/yr of extension into the narrow gulf (∼30 km wide) resulted from synchronous fault activity on neighboring faults followed by localization rather than sequential faulting, with consequences for the mechanism controlling localization of extension

Prevalence of hyaline membrane disease in black and white low-birth-weight infants

Previous studies in South Africa and elsewhere have suggested that there are ethnic differences in the prevalence of hyaline membrane disease (HMD). This study compared the prevalence of HMD between black and white infants with birth weights of 1 000 - 1 749 g. A cohort of black and one of white low-birth-weight infants were enrolled at Baragwanath and Johannesburg Hospitals respectively. Black infants were found to have a higher rate of intra-uterine growth retardation. When compared according to either birth weight or gestational age categories, black infants had a significantly lower prevalence of HMD. For example, between 29 and 34 weeks' gestation 36,2% of black and 62,5% of white infants developed HMD (P < 0,001). The reasons for these differences are not clear, however, and require further study

Symmetries of a class of nonlinear fourth order partial differential equations

In this paper we study symmetry reductions of a class of nonlinear fourth order partial differential equations \be u_{tt} = \left(\kappa u + \gamma u^2\right)_{xx} + u u_{xxxx} +\mu u_{xxtt}+\alpha u_x u_{xxx} + \beta u_{xx}^2, \ee where $\alpha$, $\beta$, $\gamma$, $\kappa$ and $\mu$ are constants. This equation may be thought of as a fourth order analogue of a generalization of the Camassa-Holm equation, about which there has been considerable recent interest. Further equation (1) is a ``Boussinesq-type'' equation which arises as a model of vibrations of an anharmonic mass-spring chain and admits both ``compacton'' and conventional solitons. A catalogue of symmetry reductions for equation (1) is obtained using the classical Lie method and the nonclassical method due to Bluman and Cole. In particular we obtain several reductions using the nonclassical method which are no} obtainable through the classical method

Power Spectrum Analysis of Physikalisch-Technische Bundesanstalt Decay-Rate Data: Evidence for Solar Rotational Modulation

Evidence for an anomalous annual periodicity in certain nuclear decay data has led to speculation concerning a possible solar influence on nuclear processes. We have recently analyzed data concerning the decay rates of Cl-36 and Si-32, acquired at the Brookhaven National Laboratory (BNL), to search for evidence that might be indicative of a process involving solar rotation. Smoothing of the power spectrum by weighted-running-mean analysis leads to a significant peak at frequency 11.18/yr, which is lower than the equatorial synodic rotation rates of the convection and radiative zones. This article concerns measurements of the decay rates of Ra-226 acquired at the Physikalisch-Technische Bundesanstalt (PTB) in Germany. We find that a similar (but not identical) analysis yields a significant peak in the PTB dataset at frequency 11.21/yr, and a peak in the BNL dataset at 11.25/yr. The change in the BNL result is not significant since the uncertainties in the BNL and PTB analyses are estimated to be 0.13/yr and 0.07/yr, respectively. Combining the two running means by forming the joint power statistic leads to a highly significant peak at frequency 11.23/yr. We comment briefly on the possible implications of these results for solar physics and for particle physics.Comment: 15 pages, 13 figure