DynPeak : An algorithm for pulse detection and frequency analysis in hormonal time series

The endocrine control of the reproductive function is often studied from the analysis of luteinizing hormone (LH) pulsatile secretion by the pituitary gland. Whereas measurements in the cavernous sinus cumulate anatomical and technical difficulties, LH levels can be easily assessed from jugular blood. However, plasma levels result from a convolution process due to clearance effects when LH enters the general circulation. Simultaneous measurements comparing LH levels in the cavernous sinus and jugular blood have revealed clear differences in the pulse shape, the amplitude and the baseline. Besides, experimental sampling occurs at a relatively low frequency (typically every 10 min) with respect to LH highest frequency release (one pulse per hour) and the resulting LH measurements are noised by both experimental and assay errors. As a result, the pattern of plasma LH may be not so clearly pulsatile. Yet, reliable information on the InterPulse Intervals (IPI) is a prerequisite to study precisely the steroid feedback exerted on the pituitary level. Hence, there is a real need for robust IPI detection algorithms. In this article, we present an algorithm for the monitoring of LH pulse frequency, basing ourselves both on the available endocrinological knowledge on LH pulse (shape and duration with respect to the frequency regime) and synthetic LH data generated by a simple model. We make use of synthetic data to make clear some basic notions underlying our algorithmic choices. We focus on explaining how the process of sampling affects drastically the original pattern of secretion, and especially the amplitude of the detectable pulses. We then describe the algorithm in details and perform it on different sets of both synthetic and experimental LH time series. We further comment on how to diagnose possible outliers from the series of IPIs which is the main output of the algorithm.Comment: Nombre de pages : 35 ; Nombre de figures : 16 ; Nombre de tableaux :

Use of group records of feed intake to select for feed efficiency in rabbit

Models for genetic evaluation of feed efficiency (FE) for animals housed in groups when they are either fed ad libitum (F) or on restricted (R) feeding were implemented. Definitions of FE on F included group records of feed intake (¯FI_F) and individual records of growth rate (GF) and metabolic weight (MF). Growth rate (GR) as FE measurement on R was used. Data corresponded to 5,336 kits from a rabbit sire line, from 1,255 litters in 14 batches and 667 cages. A five-trait mixed model (also with metabolic weight on R, MR) was implemented including, for each trait, the systematic effects of batch, body weight at weaning, parity order and litter size; and the random effects of litter, additive genetic and individual. A Bayesian analysis was performed. Conditional traits such as ¯FI_F |M_F,G_F and G_F |M_F,¯FI_F were obtained from elements of additive genetics ( ( ¯FI_F |M_F,G_F )_g and ( G_F |M_F,¯FI_F )_g ) or phenotypic (( ¯FI_F |M_F,G_F )_p and ( G_F |M_F,¯FI_F )_p ) (co)variance matrices. In the first case, heritabilities were low (0.07 and 0.06 for ( ¯FI_F |M_F,G_F )_g and ( G_F |M_F,¯FI_F )_g, respectively) but null genetic correlation between the conditional and conditioning traits is guaranteed. In the second case, heritabilities were higher (0.22 and 0.16 for ( ¯FI_F |M_F,G_F )_p and ( G_F |M_F,¯FI_F )_p, respectively) but the genetic correlation between ( ¯FI_F |M_F,G_F )_p and G_F was moderate (0.58). Heritability of GR was low (0.08). This trait was negatively correlated with ( G_F |M_F,¯FI_F )_p and ( G_F |M_F,¯FI_F )_gof animals on F, which indicate a different genetic background. The correlation between GR and GF was also low to moderate (0.48) and the additive variance of GF was almost 4 times that of GR, suggesting the presence of a substantial genotype by feeding regimen interaction.info:eu-repo/semantics/acceptedVersio

Retinopathy of prematurity: incidence and severity in Hawaii.

Because survival of low birth-weight infants requiring intensive care has improved recently, particularly since the advent of exogenous surfactant therapy, we reviewed our experience at Kapiolani Medical Center for Women and Children (KMCWC) from 1989 to 1991 to determine if the incidence of retinopathy of prematurity (ROP), a serious long-term complication, had also increased. During this 3-year period, threshold disease, the ROP stage in which cryosurgery is recommended, occurred only in infants < or = 1000 grams. Seventy-four infants < or = 1000 grams were diagnosed with ROP of any stage. Sixteen eyes (9 infants) reached threshold; 14 were treated with cryosurgery. Six of these eyes have useful vision on follow up; 8 do not. Exogenous surfactant therapy had no significant effect on ROP incidence or severity in our series. Although ROP incidence did not increase during this review period, it remains a serious problem in high-risk premature infants in our Newborn Intensive Care Unit

Modular simulation of a hybrid power system with diesel and wind turbine generation

In this paper, the authors present the modular simulation tool they developed to help study the system dynamics for wind-diesel power systems. The principal modules of the simulator, which include a diesel generator, a wind turbine generator, a rotary converter with a battery, a village load and a dump load, are described. With a case study, the authors demonstrate how the designer benefits from easily understanding the effects of system modifications. Using this tool, a designer can easily develop control strategies to balance the system power flows under different generation/load conditions

Renewables for Sustainable Village Power

This paper describes the efforts of NREL's Renewables for Sustainable Village Power team to match renewable energy technologies with rural energy needs in the international market. The paper describes the team's activities, updates the lessons learned, and proposes an integrated approach as a model for rural electrification with renewables