Stable scheduling policies for fading wireless channels

We study the problem of stable scheduling for a class of wireless networks. The goal is to stabilize the queues holding information to be transmitted over a fading channel. Few assumptions are made on the arrival process statistics other than the assumption that their mean values lie within the capacity region and that they satisfy a version of the law of large numbers. We prove that, for any mean arrival rate that lies in the capacity region, the queues will be stable under our policy. Moreover, we show that it is easy to incorporate imperfect queue length information and other approximations that can simplify the implementation of our policy.     

Hypomagnesemia following correction of metabolic acidosis: a case of hungry bones

Severe symptomatic hypomagnesemia (0.15 mmol/L [0.3 mEq/L]) and hypocalcemia (1.47 mmol/L [5.9 mg/dL]) occurred in a 4-week-old infant coincidental with correction of a severe renal tubular acidosis with alkali therapy. The patient had no evidence of gastrointestinal abnormality and magnesium (Mg) intake was adequate for age and weight. Extreme renal conservation of Mg was observed, supporting the presence of Mg depletion. We suggest that Mg depletion in this infant occurred due to acidosis-induced bone demineralization and that symptomatic hypomagnesemia was precipitated by rapid remineralization accompanying correction of systemic acidosis. This patient represents a novel case of hungry bone syndrome (HBS). Since HBS has not been described previously in patients with acidosis undergoing therapy, several other factors may have contributed to this patient's severe hypomagnesemia, namely, prematurity, twin status, severity of acidosis, rapidity of correction of acidosis, catch-up growth and calcium supplementation. Clinicians should be vigilant for HBS in infants with severe acidosis undergoing alkali therapy.     

Occupational lead exposure and hearing loss

Studies of adults, children, and laboratory animals suggest an association between lead exposure and hearing loss. A causal relationship might direct mandated medical surveillance of lead-exposed workers to include audiometric testing. A cross-sectional, computerized dataset was obtained from a private occupational health screening company to examine the relationship between blood lead level and hearing loss. Audiometry and blood lead results were available for 183 workers. A statistically significant correlation was found between blood lead level and an elevated hearing threshold at 400 Hz (P = 0.03); no other frequencies showed such a correlation. This finding suggests either an interaction between nose exposure and lead, interaction of other exposure factors (such as cigarette smoking), or that factors other than biomechanical ones render the organ of Corti more susceptible at 4000 Hz. Further evaluation of these questions should be undertaken. Computerized databases created for worker surveillance may be a source for data useful for examining other causal connections in occupational settings.     

Transrectal electrostimulation therapy for neuropathic bowel dysfunction in children with myelomeningocele

PURPOSE: We attempted to evaluate the efficacy of transrectal bowel stimulation for neurogenic bowel dysfunction in children with myelodysplasia. MATERIALS AND METHODS: Daily sessions of transrectal electrostimulation were performed on an outpatient basis for 2 to 3 weeks on children with myelodysplasia and stool incontinence. If benefits were noted, 5 to 10 additional daily sessions were performed. Complete success was defined as improvement in all parameters of interest, including decrease in the frequency of daily bowel movements, increased sensation, increased ability to hold stool and a significant subjective change in bowel habits. Moderate success implied improvement in 1 to 3 parameters and treatment failure was defined as lack of improvement in any parameter. RESULTS: A total of 55 children 2 to 14 years old (mean age 6.7) completed a mean of 18 daily sessions per patient of bowel electrostimulation. Followup ranged from 1 to 6 years. Diapers are no longer required due to defecation problems in 14 children older than 3 years. Complete success was achieved in 20 cases (36.3%) and moderate success in an additional 30 (54.5%, overall success rate 90.8%). Specifically, 89% of the patients reported elimination of stooling accidents, 82% reported increased sensation and 71% were able to hold the bowel movement. Overall 68% of the patients noticed significantly improved bowel function. Complete/moderate success of transrectal electro-stimulation was statistically significant for all 4 parameters (p < 0.05), and complete success was significant for increased sensation, ability to hold and episodes of accidents. Therapy failed in 5 children (9%). There were no untoward effects. CONCLUSIONS: Transrectal electrostimulation is a well tolerated and minimally invasive modality that provides sustainable improvement in stool continence in children with myelomeningocele and neuropathic bowel dysfunction.     

The Subjective and Reinforcing Effects of Visual and Olfactory Stimuli in Alcohol Drinking.

Nonpharmacological cues associated with drug intake may influence subjective and reinforcing effects of those drugs. Social drinkers (N = 80) participated in 2 sessions in which they rated and then consumed ad lib their preferred beer (with participants blind to brand). Visual and olfactory stimuli were obscured during 1 session (blocked) and not obscured during the other (unblocked). Dependent measures included ratings of "liking", "want another", and "desire to drink"; subjective mood; and ad lib beer consumption (reinforcement). Most ratings and ad lib consumption were lower during the blocked versus the unblocked condition. There were no interactions of blockade condition with sex and no effect of blockade on mood. These findings show that nonpharmacological stimuli associated with alcohol consumption influence alcohol's subjective and reinforcing effects. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

High-performance liquid chromatography of human milk triacylglycerols and gas chromatography of component fatty acids

Human milk triacylglycerols were separated by high-performance liquid chromatography. A 5-μ Supelcosil LC-18 column (Supelco, Inc., Bellefonte, PA) was used with acetone/acetonitrile (64∶36, vol/vol) as mobile phase. Triacylglycerols were tentatively identified based on theoretical carbon number and relative retention time. Despite changes resulting from dietary fat variation, the major component triacylglycerols were those composed of palmitic, oleic and linoleic acids. Triacylglycerols with palmitic, stearic and oleic acids were present as minor components. Fatty acids were quantified by gas chromatography relative to an internal standard. Ratios of n−6/n−3 fatty acids were found to be high than previously reported. Based on a paper presented at the Symposium on Milk Lipids held at the AOCS Annual Meeting, Baltimore, MD, April 1990.     

Measurement of neonatal responses to painful stimuli: a research review

The measurement of neonatal responses to painful stimuli remains a significant clinical problem. Although numerous measures have been evaluated, instruments that are valid, reliable, and clinically feasible are not yet available. The purpose of this paper is to critique the studies that have been done using biochemical, physiological, and behavioral measures to evaluate neonatal responses to painful stimuli. Specific issues regarding measurement in premature and critically ill neonates are emphasized. The intent of this review and critique of the literature is to stimulate additional research into the assessment of neonatal pain.