CiteULike: Author Cardinali

UWB ranging accuracy in high- and low-data-rate applications

R Cardinali — 2008-06-11T20:26:45-00:00

Microwave Theory and Techniques, IEEE Transactions on, Vol. 54, No. 4. (2006), pp. 1865-1875.

The Cramer-Rao lower bound (CRLB) was determined for different ultra-wideband (UWB) signal formats and, in particular, for the two UWB high-data-rate (HDR) signal formats proposed within the IEEE 802.15.3a Task Group, that is, the impulsive direct-sequence UWB (DS-UWB) and the nonimpulsive multiband orthogonal frequency-division multiplexing (MB-OFDM), and an impulsive time hopping (TH) UWB format close to the format for UWB low data rate (LDR) of the forthcoming IEEE 802.15.4a standard. The analysis was carried out for both ideal and multipath channels under power constraints as set by emission masks. Results obtained for HDR formats showed that DS-UWB has better ranging accuracy than does MB-OFDM, thanks to its potentially larger bandwidth and higher frequency of operation. In addition, the degree of multipath strongly affected ranging accuracy, although differently for DS-UWB versus MB-OFDM. When incorporating a correlation receiver structure as well as an Early Late gate synchronizer in the model, ranging performance proved to be related to features of the synchronization sequence. For specific synchronization sequences, in particular, the best ranging accuracy was obtained with MB-OFDM. In the case of LDR, the study analyzed the effect of pulse shape on CRLB. Results showed that a suboptimal choice of the pulse shape reduces the ranging accuracy achievable by TH-UWB signals.

Melatonin, environmental light, and breast cancer

V Srinivasan — 2008-05-10T01:58:41-00:00

Breast Cancer Research and Treatment, Vol. 108, No. 3. (20 April 2008), pp. 339-350.

Abstract Although many factors have been suggested as causes for breast cancer, the increased incidence of the disease seen in women working in night shifts led to the hypothesis that the suppression of melatonin by light or melatonin deficiency plays a major role in cancer development. Studies on the 7,12-dimethylbenz[a]anthracene and N-methyl-N-nitrosourea experimental models of human breast cancer indicate that melatonin is effective in reducing cancer development. In vitro studies in MCF-7 human breast cancer cell line have shown that melatonin exerts its anticarcinogenic actions through a variety of mechanisms, and that it is most effective in estrogen receptor (ER) α-positive breast cancer cells. Melatonin suppresses ER gene, modulates several estrogen dependent regulatory proteins and pro-oncogenes, inhibits cell proliferation, and impairs the metastatic capacity of MCF-7 human breast cancer cells. The anticarcinogenic action on MCF-7 cells has been demonstrated at the physiological concentrations of melatonin attained at night, suggesting thereby that melatonin acts like an endogenous antiestrogen. Melatonin also decreases the formation of estrogens from androgens via aromatase inhibition. Circulating melatonin levels are abnormally low in ER-positive breast cancer patients thereby supporting the melatonin hypothesis for breast cancer in shift working women. It has been postulated that enhanced endogenous melatonin secretion is responsible for the beneficial effects of meditation as a form of psychosocial intervention that helps breast cancer patients.

Flexible tag microlab development: Gas sensors integration in RFID flexible tags for food logistic

Estefania Abad — 2008-05-07T07:57:20-00:00

Sensors and Actuators B: Chemical, Vol. 127, No. 1. (20 October 2007), pp. 2-7.

The enabling technologies for the development of a flexible tag microlab for food monitoring during the logistic chain will be presented. The realisation of the system includes the integration of physical and chemical sensors with Radio Frequency IDentification (RFID) communication capabilities. The first ISO 15693 compliant semi-active tag prototype, including low power control electronics, RFID antenna, commercial sensors, memory and a thin film battery, is shown together with the development of novel ultra-low power hotplates required for this application and the process, based on the use of anisotropic conductive adhesive (ACA) flip chip technology, for gas sensors integration onto flexible substrates.

Blunting of circadian rhythms and increased acrophase variability in sleep-time hypertensive subjects.

S Perez-Lloret — 2008-02-23T22:36:39-00:00

Chronobiol Int, Vol. 25, No. 1. (2008), pp. 99-113.

24 h and ultradian rhythms of blood pressure (BP) have been previously shown to be disorganized in nocturnal hypertensive subjects. The present study was undertaken to further analyze the ultradian and circadian BP rhythm structure in sleep-time hypertensive subjects with normal or elevated awake-time BP levels. Fourier analysis was used to fit 24, 12, 8, and 6 h curves to mean BP as well as heart rate (HR) time series data derived from 24 h ambulatory blood pressure monitoring. Awake and sleep periods were defined according to individual sleep diaries. Awake-time hypertension was defined as diurnal systolic (SBP) and/or diastolic BP (DBP) means >/=135/85 mmHg. Sleep-time hypertension was defined as nocturnal SBP and/or DBP means >/=120/70 mmHg. The sample included 240 awake-time normotensive subjects (180 sleep-time normotensives and 60 sleep-time hypertensives) and 138 untreated awake-time hypertensive subjects (31 sleep-time normotensives and 107 sleep-time hypertensives). The amplitude and integrity (i.e., percent rhythm) of the 24 and 12 h BP rhythms were lower in the sleep-time hypertensive subjects and higher in the awake-time hypertensive subjects. However, no differences were detected when the integrity and amplitude of the 6 and 8 h mean BP rhythms were analyzed. The sleep-time hypertensive group showed significantly higher 24 h BP rhythm acrophase variability. No differences could be found in any of the HR rhythm parameters. Altogether, the findings suggest a disorganization of the BP circadian rhythm in sleep-time hypertensives that results in reduced 24 h rhythm amplitude and integrity that could be related to cardiovascular risk.

RR interval variation, sympathetic skin reflex and QT dispersion in the assessment of autonomic function in peripheral neuropathy.

L Parisi — 2007-05-23T19:47:19-00:00

Electromyogr Clin Neurophysiol, Vol. 39, No. 8. (December 1999), pp. 461-468.

In recent years, two simple non-invasive tests, sympathetic skin response (SSR) and RR interval variation (RRIV) have been used to assess autonomic function (Wang et al., 1994; Drory et al., 1995; Chassande et al., 1996; Bordet et al., 1996; Spitzer et al., 1997). Their easy performance by an electromyographic (EMG) machine and successful clinical correlation (Shahani et al., 1990) have made them routine in autonomic assessment in several EMG laboratories. More recently QT dispersion on electrocardiogram (ECG) has been shown to have increased in patients with diabetic neuropathy and several autonomic dysfunctions (Wei et al., 1995; Lengyel et al., 1997; Langen et al., 1997; Axelrod et al., 1997). In order to evaluate the diagnostic value of the RR interval variation, sympathetic skin response and QT dispersion combined, we performed the three tests on a group of 37 patients with several peripheral neuropathies with and without clinical signs of dysautonomia. All patients were studied using an electromyograph (EMG). The results of the SSR, RRIV and QT dispersion combined have shown abnormal values in all patients with neuropathy and clinical dysautonomia and in some patients without clinical signs of dysautonomia, suggesting a subclinical autonomic dysfunction. The principal finding of this study is that the evaluation of the RRIV, SSR and QT dispersion combined may contribute to the assessment of dysautonomia in patients with somatic neuropathy and that they may be currently performed by an electromyograph.

Coral reef fish breeding: the secrets of each species

Ike Olivotto — 2006-10-25T09:59:29-00:00

Aquaculture, Vol. 224, No. 1-4. (30 June 2003), pp. 69-78.

In recent years, the interest in the trade of tropical fish has increased significantly, with direct negative repercussions on coral reefs and marine ecosystems.The reproduction and rearing of some of the species most commonly used in the aquarium trade actually represent an economical and ecological tool for broadening development. The present study illustrates the first case ever of a small Indo-Pacific Pomacentridae, Chrysiptera parasema, successfully reared in captivity. Eggs were obtained from spawners reared in 80-l tanks under controlled conditions. Spawning began after 3 months: the couples were formed, and eggs were laid after a brief courtship. The male normally guarded the nest and chased away the female if she entered it.The eggs, about 300 in number, are demersal and elongate ovoidal in shape, measuring approximately 1.2-1.5 mm and coming with a large oil globule. Hatching took place at 28 [deg]C during the first 2 h of darkness, over a total time period of 96 h. A proper diet of enriched PUFA as a first food, combined with a photoperiod of 24L/0D, proved essential for survival of the C. parasema larvae.These results are very promising in terms of both future captive production of ornamental fish and efforts to minimize environmental impact.

Free people are not equal and equal people are not free

Cardinali — 2006-07-26T07:49:25-00:00

pp. 9-20.

Inequality and freedom mean different things to different people; whether inequality should encapsulate ethical concepts such as the desirability of a particular system of rewards or simply mean differences in income appears to be the subject of much debate. The World Bank conceptualises inequality as the dispersion of a distribution, whether that is income, consumption or some other welfare indicator or attribute of a population. When Lawrence Reed introduced his seven principles of sound public policy at a presentation at the Economic Club of Detroit, one item that stood out was his principle which stated that "free people are not equal and equal people are not free". He was not addressing the foundation of equality in society but about income and material wealth a person may earn in the marketplace, essentially he was addressing "economic equality". Hofstede touches on a number of postulates when he speaks of inequality within a society and how it is visible in the existence of different social classes: upper, the middle, and lower. According to Hofstede, classes differ in their access to and their opportunities to benefit from the advantages of society. He cites education and the benefits derived by advanced education. The World Bank has concluded that inequality in intelligence is part of the human condition and inescapably contributes to a substantial degree of income inequality that greater equality of opportunity cannot circumvent. This article examines a number of concepts which dispel formal equality theory and the belief that equality is achieved if the law treat likes alike is faulted.

Effect of melatonin treatment on oxygen consumption by rat liver mitochondria.

C F Reyes-Toso — 2006-05-23T23:58:40-00:00

Amino Acids (24 March 2006)

The objective of this study was to examine the in vivo effect of melatonin on rat mitochondrial liver respiration. Two experiments were performed: For experiment 1, adult male rats received melatonin in the drinking water (16 or 50 microg/ml) or vehicle during 45 days. For experiment 2, rats received melatonin in the drinking water (50 microg/ml) for 45 days, or the same amount for 30 days followed by a 15 day-withdrawal period. At sacrifice, a liver mitochondrial fraction was prepared and oxygen consumption was measured polarographically in the presence of excess concentration of DL-3-beta-hydroxybutyrate or L-succinate. Melatonin treatment decreased Krebs' cycle substrate-induced respiration significantly at both examined doses. The stimulation of mitochondrial respiration caused by excess concentration of substrate recovered after melatonin withdrawal. Basal state 4 respiration was not modified by melatonin. Melatonin, by curtailing overstimulation of cellular respiration caused by excess Krebs' cycle substrates, can protect the mitochondria from oxidative damage.