1,304 research outputs found
A numerical study of a method for measuring the effective in situ sound absorption coefficient
The accuracy of a method [Wijnant et al., āDevelopment and applica-
tion of a new method for the in-situ measurement of sound absorptionā, ISMA 31,
Leuven, Belgium (2010).], for measurement of the effective area-averaged in situ
sound absorption coefficient is investigated. Based on a local plane wave assump-
tion, this method can be applied to sound fields for which a model is not available.
Investigations were carried out by means of finite element simulations for a typical
case. The results show that the method is a promising method for determining the
effective area-averaged in situ sound absorption coefficient in complex sound fields
Genomic Correlates of Virulence Attenuation in the Deadly Amphibian Chytrid Fungus, Batrachochytrium dendrobatidis.
Emerging infectious diseasespose a significant threat to global health, but predicting disease outcomes for particular species can be complicated when pathogen virulence varies across space, time, or hosts. The pathogenic chytrid fungus Batrachochytrium dendrobatidis (Bd) has caused worldwide declines in frog populations. Not only do Bd isolates from wild populations vary in virulence, but virulence shifts can occur over short timescales when Bd is maintained in the laboratory. We leveraged changes in Bd virulence over multiple generations of passage to better understand mechanisms of pathogen virulence. We conducted whole-genome resequencing of two samples of the same Bd isolate, differing only in passage history, to identify genomic processes associated with virulence attenuation. The isolate with shorter passage history (and greater virulence) had greater chromosome copy numbers than the isolate maintained in culture for longer, suggesting that virulence attenuation may be associated with loss of chromosome copies. Our results suggest that genomic processes proposed as mechanisms for rapid evolution in Bd are correlated with virulence attenuation in laboratory culture within a single lineage of Bd. Moreover, these genomic processes can occur over extremely short timescales. On a practical level, our results underscore the importance of immediately cryo-archiving new Bd isolates and using fresh isolates, rather than samples cultured in the laboratory for long periods, for laboratory infection experiments. Finally, when attempting to predict disease outcomes for this ecologically important pathogen, it is critical to consider existing variation in virulence among isolates and the potential for shifts in virulence over short timescales
PROLACTIN-Deficiency in Adult Offspring of Diabetic Mothers
Maternal diabetes induces fetal alterations, resulting
in lasting consequences for the glucose tolerance
of the offspring over several generations. In our
experimental rat model, circulating prolactin, oestradiol,
progesterone and corticosterone levels,
known to influence insulin secretion and action,
are determined in plasma of female adult offspring
of mildly and severely diabetic mothers. Prolactin
and progesterone levels are equally low in both
groups as compared to controls, stressing the involvement
of the CNS in the transgeneration effect;
oestradiol and corticosterone levels are normal. No
correlation is found between these hormonal alterations
and the known differences in glucose
tolerance
Lost and Found: Decline and Reemergence of Non-Native Vowel Discrimination in the First Year of Life
Systeemtoezicht in de Nederlandse gezondheidszorg. Een experimentele innovatie van toezicht.
__Abstract__
Al jaren wordt nagedacht over de vraag in hoeverre zorginstellingen zelf in staat
zijn om te waarborgen dat zij verantwoorde zorg leveren (lees: veilige en kwalitatief
goede zorg). Er is wetgeving die voorschrijft dat zorginstellingen alleen kunnen
worden toegelaten als zij een aantal organisatorische zaken op orde hebben.1
In 1996 is in de Kwaliteitswet geregeld dat zorginstellingen zelf de kwaliteit van
de zorg systematisch moeten bewaken, beheersen en verbeteren. Bestuurders en
raden van toezicht zijn in eerste instantie zelf verantwoordelijk voor de kwaliteit
van zorg in hun instelling, waarbij zij zorgdragen voor passende procedures en
cultuur. De veronderstelling is dat als zorginstellingen deze verantwoordelijkheid
opnemen en daadwerkelijk waarmaken, het publieke toezicht op de naleving
beperkt kan worden tot toezicht op (de werking van) het zelf opgezette āsysteemā
om kwaliteit en veiligheid te borgen en risicoās te beheersen. Deze manier van
inspecteren wordt in Nederland systeemtoezicht (ST) genoemd.
De vragen die we in dit artikel willen beantwoorden zijn waarom en hoe ST aan de
toezichtmethoden van de Inspectie voor de Gezondheidszorg (IGZ) toegevoegd
zou kunnen worden
Measurement of absorption with a p-u sound intensity probe in an impedance tube
An alternative method of measuring the normal-incidence sound absorption of a sample of material in an impedance tube is examined. The method is based on measurement of the sound pressure and the normal component of the particle velocity using a "p-u" sound intensity probe. This technique is compared with the traditional, well-established "transfer function method" based on two pressure microphones. The results suggest that the new method can be as accurate as the established method, but whereas the influence of transducer mismatch on the transfer function method can be eliminated using a simple "sensor-switching technique," the method based on a p-u intensity probe relies on accurate calibration of the probe
Taenia solium Cysticercosis, Irian Jaya, Indonesia
Centers for Disease Control and Prevention, Toni, Wandra ; Akira, Ito ; Hiroshi, Yamasaki ; Thomas, Suroso ; Sri S. Margono, Emerging Infectious Diseases, 9(7), 2003, 884-885.
publishe
The links between prenatal stress and offspring development and psychopathology: disentangling environmental and inherited influences
Background. Exposure to prenatal stress is associated with later adverse health and adjustment outcomes. This is generally presumed to arise through early environmentally mediated programming effects on the foetus. However, associations could arise through factors that influence mothersā characteristics and behaviour during pregnancy which are inherited by offspring. Method. A ā prenatal cross-fostering ā design where pregnant mothers are related or unrelated to their child as a result of in vitro fertilization (IVF) was used to disentangle maternally inherited and environmental influences. If links between prenatal stress and offspring outcome are environmental, association should be observed in unrelated as well as related motherāchild pairs. Offspring birth weight and gestational age as well as mental health were the outcomes assessed. Results. Associations between prenatal stress and offspring birth weight, gestational age and antisocial behaviour were seen in both related and unrelated motherāoffspring pairs, consistent with there being environmental links. The association between prenatal stress and offspring anxiety in related and unrelated groups appeared to be due to current maternal anxiety/depression rather than prenatal stress. In contrast, the link between prenatal stress and offspring attention deficit hyperactivity disorder was only present in related motherāoffspring pairs and therefore was attributable to inherited factors. Conclusions. Genetically informative designs can be helpful in testing whether inherited factors contribute to the association between environmental risk factors and health outcomes. These results suggest that associations between prenatal stress and offspring outcomes could arise from inherited factors and post-natal environmental factors in addition to causal prenatal risk effects
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