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Critical Age (critical + age)
Selected AbstractsReassessing the value of nursery areas to shark conservation and managementCONSERVATION LETTERS, Issue 2 2009Michael John Kinney Abstract Concern over declining shark populations has led to an intense interest in their conservation and management. Due to the difficulties involved in managing adult sharks, focus has been placed on young juvenile and neonate age classes that inhabit discrete inshore nursery areas. However, past confusion over what qualifies as a nursery habitat has led to the identification of vast coastal areas as nurseries, making conservation unfeasible. With the establishment of more discerning criteria for nursery area identification such concerns have been somewhat alleviated, but while effort has been put into defining, identifying, mapping, and in some cases protecting nursery areas, little attention has been paid to the practical value of nurseries for the recovery of exploited shark populations. Often neonate and young juveniles are considered the most critical age classes in terms of population stability/recovery, but evidence is mounting that suggests life stages outside the nursery may be more important in this regard. While nursery area protection should remain a component in shark management strategies it will be critical to link early life stage conservation with management strategies that encompass older individuals residing outside nurseries if effective management is to be achieved. [source] Structural and functional changes in the olfactory pathway of adult Drosophila take place at a critical ageDEVELOPMENTAL NEUROBIOLOGY, Issue 1 2003Jean-Marc Devaud Abstract The olfactory system of several holometabolous insect species undergoes anatomical changes after eclosion of the imago, following those occurring during metamorphosis. In parallel, odor experience and learning performance also evolve with age. Here, we analyze the case of adult Drosophila females. Synaptogenesis in the antennal lobe (AL) starts in late pupa and continues during the first days of adult life, at the same time as the behavioral response to odors matures. Individual olfactory glomeruli (DM6, DM2, and V) display specific growth patterns between days 1 and 12 of adult life. Experience can modify the olfactory pathway both structurally and functionally as shown by adaptation experiments. The modifications associated with this form of nonassociative learning seem to take place at a critical age. Exposure to benzaldehyde at days 2,5 of adult life, but not at 8,11, causes behavioral adaptation as well as structural changes in DM2 and V glomeruli. Altered levels in intracellular cAMP, caused by dunce and rutabaga mutants, do not affect the normal changes in glomerular size, at least at day 6 of development, but they prevent those elicited by experience, establishing a molecular difference between glomerular changes of intrinsic versus environmental origin. Taken together, these data demonstrate an imprinting-like phenomenon in the olfactory pathway of young Drosophila adults, and illustrate its glomerulus-specific dynamics. © 2003 Wiley Periodicals, Inc. J Neurobiol 56: 13,23, 2003 [source] Identification of Critical Stage for Disease Development and Biocontrol of Alternaria Blight of Indian Mustard (Brassica juncea)JOURNAL OF PHYTOPATHOLOGY, Issue 4 2004P. D. Meena Abstract Fungicides mancozeb and carbendazim caused 100% reduction in mycelial growth of Alternaria brassicae over control in vitro while 1% (w/v) aqueous bulb extract of Allium sativum and leaf extract of Acacia nilotica caused significant reductions. In dual culture, GR isolate of Trichoderma viride performed the best among the test isolates of Trichoderma, causing 81%, 82% reduction in mycelial growth of A. brassicae over control. Performance of isolates SI-2, P and SI-1 of T. viride were at par (P < 0.01) with that of GR isolate. Spraying of A. brassicae at different ages of the mustard host plant identified 75 days after sowing (d.a.s.) as the most critical age of the mustard plant for development of Alternaria blight severity on the crop with 45 d.a.s. being the next most important one. Mancozeb was the best among all the treatments, resulting in the lowest disease severity on leaves of mustard at both Sewar and Ludhavai as also the lowest A-value (area under disease progress curve). Performance of bulb extract of A. sativum in checking the disease severity on leaves and pods was at par (P,<,0.05) with mancozeb. The GR isolate of T. viride was at par with mancozeb in checking blight severity on mustard leaves at Sewar while performance of the bioagent was significantly (P,<,0.05) inferior to the chemical fungicide at Ludhavai. Performance of the bioagent isolate GR of T. viride in checking the disease severity on pods was at par (P < 0.05) with mancozeb at both Sewar and Ludhavai, the treatment recording the lowest A-value on pods. While application of bulb extract of A. sativum resulted in highest seed yield at Sewar in 2001,2002, the bioagent isolate GR of T. viride did so at Ludhavai, both the treatments being at par (P < 0.05) with mancozeb and significantly higher than control. Application of bulb extract of A. sativum at 45 and 75 d.a.s. resulted in lowest blight severity on leaves and pods as also in highest seed yield among the different single and combination of treatments. Although disease severity in the treatment was at par (P < 0.05) with that in mancozeb, application of the plant extract at the two stages of crop growth resulted in significantly higher seed yield compared with the two applications of the chemical fungicide. However, application of the treatments singly only at 75 d.a.s., GR isolate of T. viride at 45 and 75 d.a.s., A. sativum 45 d.a.s. + T. viride 75 d.a.s., and T. viride 45 d.a.s. + A. sativum 75 d.a.s. resulted in seed yield at par (P < 0.05) with application of bulb extract of A. sativum at 45 and 75 d.a.s. [source] Patterns of Ethanol Intake in Preadolescent, Adolescent, and Adult Wistar Rats Under Acquisition, Maintenance, and Relapse-Like ConditionsALCOHOLISM, Issue 4 2009David García-Burgos Background:, Animal behavioral models of voluntary ethanol consumption represent a valuable tool to investigate the relationship between age and propensity to consume alcohol using an experimental methodology. Although adolescence has been considered as a critical age, few are the studies that consider the preadolescence age. This study examines the ethanol consumption/preference and the propensity to show an alcohol deprivation effect (ADE) after a short voluntary ethanol exposure from a developmental perspective. Methods:, Three groups of heterogeneous Wistar rats of both sexes with ad libitum food and water were exposed for 10 days to 3 ethanol solutions at 3 different ontogenetic periods: preadolescence (PN19), adolescence (PN28), and adulthood (PN90). Ethanol intake (including circadian rhythm), ethanol preference, water and food consumption, and ADE were measured. Results:, During the exposure, the 3 groups differed in their ethanol intake; the greatest amount of alcohol (g/kg) was consumed by the preadolescent rats while the adolescents showed a progressive decrease in alcohol consumption as they approached the lowest adult levels by the end of the assessed period. The pattern of ethanol consumption was not fully explained in terms of hyperphagia and/or hyperdipsia at early ages, and showed a wholly circadian rhythm in adolescent rats. After an abstinence period of 7 days, adult rats showed an ADE measured both as an increment in ethanol consumption and preference, whereas adolescent rats only showed an increment in ethanol preference. Preadolescent rats decreased their consumption and their preference remained unchanged. Conclusions:, In summary, using a short period of ethanol exposure and a brief deprivation period the results revealed a direct relationship between chronological age and propensity to consume alcohol, being the adolescence a transition period from the infant to the adult pattern of alcohol consumption. Preadolescent animals showed the highest ethanol consumption level. The ADE was only found in adult animals for both alcohol consumption and preference, whereas adolescents showed an ADE only for preference. No effect of sex was detected in any phase of the experiment. [source] The Challenge of asthma in adolescencePEDIATRIC PULMONOLOGY, Issue 8 2007Diletta de Benedictis MD Abstract The adolescents with asthma are a distinct group of patients with different problems and needs compared to children and adults. Specific issues of asthma in adolescence are the variability of the clinical spectrum, the presence of particular risk factors for the persistence of symptoms, underdiagnosis and undertreatment of the disease. Refusal of the sick role, denial of symptoms, carelessness about dangerous inhalation exposure, erratic self-medication, overexertion without taking precautions against exercise-induced asthma, and a poor relationship between patients, their families, and often doctors are the main obstacles to successful management of asthma in this critical age. There are also major problems of compliance for these patients. The goal of optimal quality of life will be achieved only if the physician thoroughly understands the adolescent's needs and provides optimal care. Pediatr Pulmonol. 2007, 42:683,692. © 2007 Wiley-Liss, Inc. [source] Age as only predictive factor for successful sperm recovery in patients with Klinefelter's syndromeANDROLOGIA, Issue 2 2009K. Ferhi Summary The study was performed to determine factors affecting successful sperm retrieval by testicular sperm extraction in patients with nonmosaic Klinefelter's syndrome (KS). From May 2001 to February 2007, 27 azoospermic patients were diagnosed as having nonmosaic KS. All patients underwent sperm testicular extraction. Patient's age, testicular volume, serum follicle-stimulating hormone (FSH) and inhibin B were assessed as predictive factors for successful sperm recovery. Of the 27 Klinefelter's patients examined, eight (29.6%) had successful sperm recovery. The comparisons of serum FSH, inhibin B and testicular volume between patients with and without successful sperm retrieval did not show any statistical significance. The patients with successful sperm recovery were significantly younger (28.6 ± 3.11 years) than those with failed attempts (33.9 ± 4.5 years, P = 0.002). The rate of positive sperm retrieval was significantly higher in patients younger than 32 years compared with patients older than 32 years (P = 0.01, chi-squared test). The study showed that clinical parameters such as FSH, inhibin B and testicular volume do not have predictive value for sperm recovery in patients with KS. The mean age of our patients with successful sperm recovery was significantly lower than that of men with unsuccessful results. Testicular sperm extraction or testicular sperm aspiration should be performed before the critical age of 32 years. [source] |