102,814 research outputs found
Corrigenda to and validation of Ozophora woodruffi Slater 2005 (Hemiptera: Lygaeidae)
Important missing specimen data are provided for the original description of Ozophora woodruffi Slater (2005: 245) (Hemiptera: Lygaeidae), along with additional comparative relationships. Because of the missing type information, according to ICZN rules (1999), the species became a nomen nudum. This paper now serves to validate the name, and authorship becomes Slater (2012)
Rates and equilibria at the acetylcholine receptor of electrophorus electroplaques. A study of neurally evoked postsynaptic currents and of voltage-jump relaxations
Kinetic measurements are employed to reconstruct the steady-state activation of acetylcholine [Ach] receptor channels in electrophorus electroplaques. Neurally evoked postsynaptic currents (PSCs) decay exponentially; at 15°C the rate constant, α, equals 1.2 ms^(-1) at 0 mV and decreases e-fold for every 86 mV as the membrane voltage is made more negative. Voltage-jump relaxations have been measured with bath-applied ACh, decamethonium, carbachol, or suberylcholine. We interpret the reciprocal relaxation time 1/τ as the sum of the rate constant α for channel closing and a first-order rate constant for channel opening. Where measureable, the opening rate increases linearly with [agonist] and does not vary with voltage. The voltage sensitivity of small steady-state conductances (e- fold for 86 mV) equals that of the closing rate α, confirming that the opening rate has little or no additional voltage sensitivity. Exposure to α-bungarotoxin irreversibly decreases the agonist-induced conductance but does not affect the relaxation kinetics. Tubocurarine reversibly reduces both the conductance and the opening rate. In the simultaneous presence of two agonist species, voltage-jump relaxations have at least two exponential components. The data are fit by a model in which (a) the channel opens as the receptor binds the second in a sequence of two agonist molecules, with a forward rate constant to 10^(7) to 2x10^(8) M^(-1)s^(-1); and (b) the channel then closes as either agonist molecule dissociates, with a voltage-dependent rate constant of 10^(2) to 3x10^(3)s^(-1)
International Trade and Economic Development Strategy: Can Foreign Direct Investment Be Predicted?
This study identifies factors that might be used by the state to better target foreign industries and countries that are more likely to be seeking investment opportunities in the U.S
Functional Stoichiometry at the Nicotinic Receptor. The Photon Cross Section for Phase 1 Corresponds to Two Bis-Q Molecules per Channel
These experiments examine changes in the agonist-induced conductance
that occur when the agonist-receptor complex is perturbed. Voltage-clamped
Electrophorus electroplaques are exposed to the photoisomerizable agonist
trans-Bis-Q A 1-µs laser flash photoisomerizes some trans-Bis-Q molecules
bound to receptors; because the cis configuration is not an agonist, receptor
channels close within a few hundred microseconds. This effect is called phase 1.
We compare (a) the fraction of channels that close during phase 1 with (b) the
fraction of trans-Bis-Q molecules that undergo trans → cis photoisomerization.
Parameter a is measured as the fractional diminution in voltage-clamp currents
during phase 1. Parameter b is measured by changes in the optical spectra of
Bis-Q solutions caused by flashes . At low flash intensities, a is twice b, which
shows that the channel can be closed by photoisomerizing either of two bound
agonist molecules. Conventional dose-response studies with trans-Bis-Q also give
a Hill coefficient of two. As a partial control for changes in the photochemistry
caused by binding of Bis-Q to receptors, spectral measurements are performed
on the photoisomerizable agonist QBr, covalently bound to solubilized acetylcholine
receptors from Torpedo. The bound and free agonist molecules have the
same photoisomerization properties. These results verify the concept that the
open state of the acetylcholine receptor channel is much more likely to be
associated with the presence of two bound agonist molecules than with a single
such molecule
Parenting Latino Toddlers and Preschoolers: Clinical and Nonclinical Samples
Parenting practices contribute significantly to the social-emotional development of young children. There is limited literature that addresses the role of culture in parenting, particularly among Latino families who have very young children with significant behavior problems. The current study compared the parenting practices of 30 low-income Latino mothers whose young children had been referred for mental health services for their behavior problems with a similar group of 30 mothers of children without behavior problems. Results showed that mothers in the clinical sample nurtured their children less often and used more frequent verbal and corporal punishment as discipline than the nonclinical sample. The clinical sample also had a significantly higher incidence of mental health problems in their families. Results also showed the significant toll that raising young children with challenging behaviors takes on their mothers. The implications of these findings for the early identification of these children are discussed
JPL's Real-Time Weather Processor project (RWP) metrics and observations at system completion
As an integral part of the overall upgraded National Airspace System (NAS), the objective of the Real-Time Weather Processor (RWP) project is to improve the quality of weather information and the timeliness of its dissemination to system users. To accomplish this, an RWP will be installed in each of the Center Weather Service Units (CWSUs), located in 21 of the 23 Air Route Traffic Control Centers (ARTCCs). The RWP System is a prototype system. It is planned that the software will be GFE and that production hardware will be acquired via industry competitive procurement. The ARTCC is a facility established to provide air traffic control service to aircraft operating on Instrument Flight Rules (IFR) flight plans within controlled airspace, principally during the en route phase of the flight. Covered here are requirement metrics, Software Problem Failure Reports (SPFRs), and Ada portability metrics and observations
Appropriate Classification of Obesity in Mentally Retarded Adults
Triceps skinfold thickness and body weight measures were obtained for 44 female and 40 male mentally retarded adults participating in a sheltered workshop setting. Subiects\u27 relative weights and skinfold thicknesses were found to correlate reasonably well for females and males, rs = .88 and .59, respectively. Use of only height and weight tables for determining the presence of obesity, however, resulted in 22.5 percent of the males and 13 .7 percent of the females being misclassified as nonobese. The distinction between overweight and obesity was discussed. Clinical/research implications of the findings were delineated
A review of California sea otter, Enhydra lutris, surveys
Recent surveys (1977 to 1983) of the sea otter, Enhydra lutris, in California were summarized and compared to past surveys, to evaluate the adequacy of current survey design and to-make inferences about current population status.
Ground counts within selected index areas provided the best
indicator of population trends. These data suggest a rather
remarkable stability in the long-term occupied range. Rangewide aerial surveys with ground truth stations provided the best available data for estimating total population size. The most recent (1979) survey yielded a population estimate of approximately 1500 sea otters. Comparisons with past surveys suggest there have been no demonstrable changes in population size since at least 1976. (34pp.
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