No abstract

We argue that a process of social interest is a balance of order and randomness, thereby producing a departure from a stationary diffusion process.The strength of this effect vanishes if the order to randomness intensity ratio vanishes, and this property allows us to reveal, although in an indirect way, the existence of a finite order to randomness intensity ratio. We aim at detecting this effect. We introduce a method of statistical analysis alternative to the compression procedures, with which the limitations of the traditional Kolmogorov-Sinai approach are bypassed. We prove that this method makes it possible for us to build up a memory detector, which signals the presence of even very weak memory, provided that this is persistent over large time intervals. We apply the analysis to the study of the teen birth phenomenon and 1 we find that the unmarried teen births are a manifestation of a social process with a memory more intense than that of the married teens. We attempt to give a social interpretation of this effect.

A prospective randomized controlled trial was performed to compare the effects of ibuprofen with indomethacin on cerebral hemodynamics measured using near infrared spectroscopy in preterm infants during treatment for patent ductus arteriosus. Infants were randomly assigned to three intravenous doses of either indomethacin (0.20-0.25 mg/kg, 12 hourly) or ibuprofen (5-10 mg/kg, 24 hourly) and also received a dose of saline. The primary end points of the study were the effects of the first dose on cerebral blood flow (CBF) and cerebral blood volume. Fifteen infants received indomethacin and 18 received ibuprofen. The group mean (SD) values for CBF (mL x 100 g(-1) x min(-1)) before and after the first dose of indomethacin were 13.6 (4.1) and 8.3 (3.1), respectively, the change being significant (p<0.001). In contrast, no significant changes in CBF were observed with the first dose of ibuprofen, the respective before and after values being 13.3 (3.2) and 14.9 (4.7) mL x 100 g(-1) x min(-1). The median (interquartile range) value for change in cerebral blood volume (mL/100 g) after the first dose in the indomethacin group was -0.4 (-0.3 to -0.6) and in the ibuprofen group was 0.0 (0.1 to -0.1), the difference between the two groups being significant (p<0.001). Cerebral oxygen delivery changed significantly after the first dose in the indomethacin group but not in the ibuprofen group. Significant reductions in CBF, cerebral blood volume, and cerebral oxygen delivery also occurred after the 24-h dose of indomethacin, but there were no significant changes after the 48-h dose of saline in the indomethacin group or after the 24- and 48-h doses of ibuprofen. The patent ductus arteriosus closure rates after indomethacin and ibuprofen were 93 and 78%, respectively. We conclude that ibuprofen, unlike indomethacin, has no adverse effects on cerebral hemodynamics and appears to mediate patent ductus arteriosus closure.

These Australian findings not only contribute to other international studies that identify why nursing care is omitted, it provides a framework for why reported episodes of missed care can be predicted and subsequently addressed.

Over a period of six months, seven cases were documented oftrauma to the nose as a result of flow driver continuous positive airway pressure in babies of very low birthweight (VLBW). There was a complication rate of 20% in the babies who required it. Deformitiesconsisted of columelia nasi necrosis which can occur within three days, flaring ofnostrils which worsens with duration of continuous positive airway pressure, and snubbing of the nose which persists after prolonged continuous positive airway pressure.These complications should be preventable by modifications to the mechanism and method of use. (Arch Dis Child 1996;75:F209-F212)

We describe two types of memory and illustrate each using artificial and actual heartbeat data sets. The first type of memory, yielding anomalous diffusion, implies the inverse power-law nature of the waiting time distribution and the second the correlation among distinct times, and consequently also the occurrence of many pseudoevents, namely, not genuinely random events. Using the method of diffusion entropy analysis, we establish the scaling that would be determined by the real events alone. We prove that the heart beating of healthy patients reveals the existence of many more pseudoevents than in the patients with congestive heart failure. The analysis of time series of physiological significance is currently done by many research groups using the paradigm of anomalous scaling ͓1͔. This means that a time series is converted into a diffusion process described by the probability distribution p(x,t) of the diffusing variable x, which is expected to fit the scaling propertywith the ''degree of anomaly'' being measured by the distance of the scaling parameter ␦ from the standard value 0.5.It is straightforward to prove that the Shannon entropyof a process fitting the scaling condition of Eq. ͑1͒ yieldswhere A is a constant, whose explicit form is not relevant for the ensuing discussion. This result is immediately obtained by plugging Eq. ͑1͒ into Eq. ͑2͒. We thus find a method to evaluate the scaling parameter ␦, more efficient than the calculation of the second moment of the probability distribution. Note that when the distribution density under study departs from the ordinary Gaussian case and the function F(y) has slow tails with an inverse power-law nature ͓2,3͔ the second moment is a divergent quantity. This diverging quantity is made finite by the unavoidable statistical limitation. In this case, the second moment analysis would yield misleading results, determined by the statisticaly inaccuracy, while the method based on Eq. ͑3͒ yields correct results ͓2,3͔. This method is denoted as diffusion entropy ͑DE͒ method. The aim of this paper is to show that the entropy of a diffusion process generated by a physiological time series according to the prescriptions of Refs. ͓2,3͔ yields a scaling exponent that depends only on genuinely random events. The time distances 's between nearest-neighbor events can be evaluated numerically and can be associated to a density distribution (). In the case of physiological processes, the waiting time distribution is expected to be an inverse power law, with index . According to the theory of Ref. ͓3͔ there exists a simple relation between ␦ and . Thus, the experimental determination of () should yield the same information as the DE method. This is true when the events are genuinely random events. If the events are not genuinely random, and a memory, or time correlation exists, the DE method and the direct evaluation of () do not yield equivalent results, and the conflict betwen them is an important information on the physiological process under study.Prior to the physiological...

The adoption of the Kolmogorov-Sinai (KS) entropy is becoming a popular research tool among physicists, especially when applied to a dynamical system fitting the conditions of validity of the Pesin theorem. The study of time series that are a manifestation of system dynamics whose rules are either unknown or too complex for a mathematical treatment, is still a challenge since the KS entropy is not computable, in general, in that case. Here we present a plan of action based on the joint action of two procedures, both related to the KS entropy, but compatible with computer implementation through fast and efficient programs. The former procedure, called Compression Algorithm Sensitive To Regularity (CASToRe), establishes the amount of order by the numerical evaluation of algorithmic compressibility. The latter, called Complex Analysis of Sequences via Scaling AND Randomness Assessment (CASSANDRA), establishes the complexity degree through the numerical evaluation of the strength of an anomalous effect. This is the departure, of the diffusion process generated by the observed fluctuations, from ordinary Brownian motion. The CASSANDRA algorithm shares with CASToRe a connection with the Kolmogorov complexity. This makes both algorithms especially suitable to study the transition from dynamics to thermodynamics, and 1 the case of non-stationary time series as well. The benefit of the joint action of these two methods is proven by the analysis of artificial sequences with the same main properties as the real time series to which the joint use of these two methods will be applied in future research work.

In this study, we argue that contemporary nursing care has been overtaken by new public management strategies aimed at curtailing budgets in the public hospital sector in Australia. Drawing on qualitative interviews with 15 nurses from one public acute hospital with supporting documentary evidence, we demonstrate what happens to nursing work when management imposes rounding as a risk reduction strategy. In the case study outlined rounding was introduced across all wards in response to missed care, which in turn arose as a result of work intensification produced by efficiency, productivity, effectiveness and accountability demands. Rounding is a commercially sponsored practice consistent with new public management. Our study illustrates the impact that new public management strategies such as rounding have on how nurses work, both in terms of work intensity and in who controls their labour.