Febrile Convulsions as a Problem in Waiting Times

A simple hypothesis on the occurrence of febrile convulsions is posed. This is (1) that certain children are genetically predisposed, and (2) that for such children, the probability of the first attack occurring in year 1, 2, etc., is essentially constant up to the end of the period during which the attacks can take place. These assumptions lead to a probability model which agrees well with data on age at first attack in the Town of Tecumseh, Mich. It appears that susceptibility does not gradually diminish, but rather disappears abruptly. The calculation yields an estimate of the proportion of children, among those susceptible, who will have at least one attack before they exceed the age of suceptibility. Penetrance of the condition, measured in this way, is nearly complete: 93.8% will have manifested the condition by age 7. The population frequency of the susceptible type of child is found to be 3.90%. If one assumes the simple dominant mode of inheritance of Frantzen et al. to be correct, this estimate of population frequency leads to an estimate of the gene frequency. This is approximately p = 0.02. The homozygote would therefore have a frequency of 4 per 10,000. Some speculations on verifying this theory of inheritance by identifying the homozygote are given. RÉSUMÉ On Émet une hypothÈse simple sur la survenue des convulsions fÉbriles, À savoir (1) que certains enfants sont gÉnÉtiquement prÉdisposÉs et (2) que pour ces enfants la probabilitÉ d'apparition de la premiÈre crise dans la premiÈre, la seconde annÉe, etc. est essentiellement constante jusqu'À la fin de la pÉriode pendant laquelle les crises peuvent survenir. De telles suppositions conduisent ÀÉtablir un modÈle de probabilite qui concorde bien avec les donnÉes sur l'Âge de la premiÈre crise, dans la ville de Techumseh, dans le Michigan. Il en ressort que cette prÉdisposition ne diminue pas progressivement, mais au contraire, disparaÎt brusquement. Les calculs permettent d'estimer la proportion d'enfants prÉdisposÉs qui auront au moins une crise, avant d'avoir dÉpassÉ l'Âge limite de la prÉdisposition. La pÉnÉtrance de cette condition, ainsi ÉvaluÉe, est presque complÈte: 93.8% des enfants auront manifestÉ cette condition À l'Âge de 7 ans. La frÉquence des enfants prÉdisposÉs dans la population est de 3.90%. Si l'on considÈre que le mode d'hÉrÉditÉ dominante simple de Frantzen est valable, cette estimation de la frÉquence dans la population conduit À une Évaluation de la frÉquence du gÈne. Celle-ci est approximativement de p = 0.02; l'homozygote aurait done une frÉquence de 4/10.000. Les possibilitÉs de vÉrifier cette thÉorie des modalitÉs hÉrÉditaires par l'identification de l'homozygote sont discutÉes.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/65705/1/j.1528-1157.1972.tb05265.x.pd

Impact of Grazing Management Strategies on Carbon Sequestration in a Semi-Arid Rangeland, USA

The effects of 12 years of grazing management strategies on carbon (C) distribution and sequestration were assessed on a semi-arid mixed-grass prairie in Wyoming, USA. Five grazing treatments were evaluated: non-grazed exclosures; continuous, season-long grazing at a light (22 steer-days ha-1) stocking rate; and, rotationally-deferred, short-duration rotation, and continuous, season-long grazing, all three at a heavy stocking rate (59 steer-days ha-1). Non-grazed exclosures exhibited a large buildup of dead plant material (72% of total aboveground plant matter) and forb biomass represented a large component (35%) of the plant community. Stocking rate, but not grazing strategy, changed plant community composition and decreased surface litter. Light grazing decreased forbs and increased cool-season mid-grasses, resulting in a highly diversified plant community and the highest total production of grasses. Heavy grazing increased warm-season grasses at the expense of the cool-season grasses, which decreased total forage production and opportunity for early season grazing. Compared to the exclosures, all grazing treatments resulted in significantly higher levels of C (6000-9000 kg ha-1) in the surface 15 cm of the soil. Higher levels of soil C with grazing are likely the result of faster litter decomposition and recycling, and redistribution of C within the 0-60 cm plant-soil system. Grazing at an appropriate stocking rate had beneficial effects on plant composition, forage production, and soil C sequestration. Without grazing, deterioration of the plant-soil system is indicated

Inhibitory top-down projections from zona incerta mediate neocortical memory

Top-down projections convey a family of signals encoding previous experiences and current aims to the sensory neocortex, where they converge with external bottom-up information to enable perception and memory. Whereas top-down control has been attributed to excitatory pathways, the existence, connectivity, and information content of inhibitory top-down projections remain elusive. Here, we combine synaptic two-photon calcium imaging, circuit mapping, cortex-dependent learning, and chemogenetics in mice to identify GABAergic afferents from the subthalamic zona incerta as a major source of top-down input to the neocortex. Incertocortical transmission undergoes robust plasticity during learning that improves information transfer and mediates behavioral memory. Unlike excitatory pathways, incertocortical afferents form a disinhibitory circuit that encodes learned top-down relevance in a bidirectional manner where the rapid appearance of negative responses serves as the main driver of changes in stimulus representation. Our results therefore reveal the distinctive contribution of long-range (dis)inhibitory afferents to the computational flexibility of neocortical circuits

A laser-induced mouse model with long-term intraocular pressure elevation

Purpose: To develop and characterize a mouse model with intraocular pressure (IOP) elevation after laser photocoagulation on the trabecular meshwork (TM), which may serve as a model to investigate the potential of stem cell-based therapies for glaucoma. Methods: IOP was measured in 281 adult C57BL/6 mice to determine normal IOP range. IOP elevation was induced unilaterally in 50 adult mice, by targeting the TM through the limbus with a 532-nm diode laser. IOP was measured up to 24 weeks post-treatment. The optic nerve damage was detected by electroretinography and assessed by semiautomatic counting of optic nerve axons. Effects of laser treatment on the TM were evaluated by histology, immunofluorescence staining, optical coherence tomography (OCT) and transmission electron microscopy (TEM). Results: The average IOP of C57BL/6 mice was 14.5±2.6 mmHg (Mean ±SD). After laser treatment, IOP averaged above 20 mmHg throughout the follow-up period of 24 weeks. At 24 weeks, 57% of treated eyes had elevated IOP with the mean IOP of 22.5±2.5 mmHg (Mean ±SED). The difference of average axon count (59.0%) between laser treated and untreated eyes was statistically significant. Photopic negative response (PhNR) by electroretinography was significantly decreased. CD45+ inflammatory cells invaded the TM within 1 week. The expression of SPARC was increased in the TM from 1 to 12 weeks. Histology showed the anterior chamber angle open after laser treatment. OCT indicated that most of the eyes with laser treatment had no synechia in the anterior chamber angles. TEM demonstrated disorganized and compacted extracellular matrix in the TM. Conclusions: An experimental murine ocular hypertension model with an open angle and optic nerve axon loss was produced with laser photocoagulation, which could be used to investigate stem cell-based therapies for restoration of the outflow pathway integrity for ocular hypertension or glaucoma. Copyright

Axonal Translation of -Catenin Regulates Synaptic Vesicle Dynamics

Many presynaptic transcripts have been observed in axons, yet their role in synapse development remains unknown. Using visually and pharmacologically isolated presynaptic terminals from dissociated rat hippocampal neurons, we found that ribosomes and β-catenin mRNA preferentially localize to recently formed boutons. Locally translated β-catenin accumulates at presynaptic terminals where it regulates synaptic vesicle release dynamics. Thus, local translation of β-catenin is a newly described mechanism for axons to independently functionalize nerve terminals at great distances from cellular somata

Discriminatory behavior in New York restaurants: 1950 and 1981

Survey techniques are combined with behavioral observations in this attempt to replicate a 1950 baseline study in order to examine trends in racial discrimination. In the 1950 study, treatment of black and white couples was compared in a sample of 62 restaurants drawn from a population of all restaurants in a large area of East Side Manhattan. In 1981 we carried out similar comparisons in a sample of 20 restaurants (plus four replications) drawn from the same area, following as closely as possible the procedures used in the baseline study. A substantial amount of discrimination was found in 1981, though somewhat less than in 1950. The difficult problems of determining when discrimination has and has not occurred are discussed from the standpoints of both black customers and social science investigators.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/43682/1/11205_2005_Article_BF02193666.pd

Managing the Socially Marginalized: Attitudes Towards Welfare, Punishment and Race

Welfare and incarceration policies have converged to form a system of governance over socially marginalized groups, particularly racial minorities. In both of these policy areas, rehabilitative and social support objectives have been replaced with a more punitive and restrictive system. The authors examine the convergence in individual-level attitudes concerning welfare and criminal punishment, using national survey data. The authors\u27 analysis indicates a statistically significant relationship between punitive attitudes toward welfare and punishment. Furthermore, accounting for the respondents\u27 racial attitudes explains the bivariate relationship between welfare and punishment. Thus, racial attitudes seemingly link support for punitive approaches to opposition to welfare expenditures. The authors discuss the implications of this study for welfare and crime control policies by way of the conclusion

Family Structure and Voter Turnout

Abstract We use data from the Voting and Registration Supplement of the Current Population Survey to explore the effects of family structure on turnout in the 2000 presidential election. Our results indicate that family structure, defined as marital status and the presence of children, has substantial consequences for turnout. Married adults are more likely to vote than are those who have never been married; in turn, previously married people are the lightest voters. Children have a smaller but still noteworthy effect on turnout. These results are only partially explained by social and demographic differences