FT Values Research Articles

Dental caries in adult Lithuanians

There are few data on the incidence of dental caries in Lithuanian adults. The aim of the present study was to describe caries and treatment experience among 35-44 and 65-74-year-olds, and to relate this to certain selected independent variables (gender, urban/rural residence, drinking water fluoride levels, and years of education). A total of 680 subjects selected based on a stratified random sampling procedure (response rate 52%) were examined by one examiner. Dental caries was recorded as DMFT following the WHO recommendations. The results showed that the median DMFT scores were 18 for the 35-44-year-olds (n = 380) with median DT = 2, MT = 5, FT = 7. For the 65-74-year-olds (n = 300) the median DMFT was 24, with DT = 1, MT = 18, FT = 2, respectively. One percent of all 35-44-year-olds and 11% of 65-74-year-olds were edentulous. In the younger age group, statistically significant differences in the DMFT scores were related to gender, urbanization and drinking water fluoride levels. Participants from areas with high fluoride content in the drinking water (>1.5 ppm F/l) had lower DT, MT, and FT values. Females and participants from urban areas had higher numbers of FT. Participants with more years of education had lower DT, MT, and higher FT values. In the elderly, DMFT scores were related to water fluoride levels and years of education. Individuals with more years of education had higher numbers of FT and lower MT values in this age group. Poor oral hygiene was associated with high numbers of DT in both age groups. The data indicate that dental caries is widespread among adult Lithuanians.

A self-consistent lumped radio frequency linear network model for MOSFETs taking into account the gate resistance

This paper describes a self-consistent lumped linear network model for MOSFETs that takes into account the distributed nature of the gate resistance. The model is verified with experimental results. The self-consistent model consists of placing a lumped resistance in series with the gate. The lumped resistance takes the value of the total gate resistance divided by a factor of three. To second order in jω, this is shown to be almost an exact approximation in determining all y-parameters and the equivalent noise resistance. The third-order terms, however, give rise to a 17% error. The value of ft for a MOS transistor shows no dependence with the gate resistance to all orders in jω. Furthermore, we also show that the thermal noise arising from the distributed gate resistance does not contribute to any additional equivalent input current noise. PACS No.: 73.40

A self-consistent lumped radio frequency linear network model for MOSFETs taking into account the gate resistance

This paper describes a self-consistent lumped linear network model for MOSFETs that takes into account the distributed nature of the gate resistance. The model is verified with experimental results. The self-consistent model consists of placing a lumped resistance in series with the gate. The lumped resistance takes the value of the total gate resistance divided by a factor of three. To second order in jω, this is shown to be almost an exact approximation in determining all y-parameters and the equivalent noise resistance. The third-order terms, however, give rise to a 17% error. The value of ft for a MOS transistor shows no dependence with the gate resistance to all orders in jω. Furthermore, we also show that the thermal noise arising from the distributed gate resistance does not contribute to any additional equivalent input current noise. PACS No.: 73.40

Evaluating a Ground-Beef Patty Cooking Process Using the General Method of Process Calculation

The General Method of process evaluation is used to calculate F160.0°F values for two ground-beef patty frying tests. The F160.0°F value is then used to compare the adequacy of the two frying processes to control pathogenic microorganisms. The several elements of process design and evaluation are described: (1) designing the microbial control process, (2) performing the General Method of process calculation including construction of the relative kill time graph, (3) selecting the z value, (4) evaluating relative kill time, lethal rates, and FT values, and (5) calculating F160.0°F values for two ground-beef patty frying tests as examples.

On a Babcock‐Leighton Solar Dynamo Model with a Deep‐seated Generating Layer for the Toroidal Magnetic Field. IV.

The study is continued of a dynamo model of the Babcock-Leighton type (i.e., the surface eruptions of toroidal magnetic field are the source for the poloidal field) with a thin, deep seated layer (GL), for the generation of the toroidal field, B. The partial differential equations satisfied by B and by the vector potential for the poloidal field are integrated in time with the help of a second order time- and space-centered finite different scheme. Axial symmetry is assumed; the gradient of the angular velocity in the GL is such that within this layer a transition to uniform rotation takes place; the meridional motion, transporting the poloidal field to the GL, is poleward and about 3 m s-1 at the surface; the radial diffusivity ηr equals 5 × 109 cm2 s-1, and the horizontal diffusivity ηθ is adjusted to achieve marginal stability. The initial conditions are: a negligible poloidal field, and a maximum value of |B| in the GL equal to 1.5 × Bcr, where Bcr is a prescribed field. For every time step the maximum value of |B| in the GL is computed. If this value exceeds Bcr, then there is eruption of a flux tube (at the latitude corresponding to this maximum) that rises radially to the surface. Only one eruption is allowed per time step (Δt) and B in the GL is unchanged as a consequence of the eruption. The ensemble of eruptions is the source for the poloidal field, i.e., no use is made of a mean field equation relating the poloidal with the toroidal field. For a given value of Δt, and since the problem is linear, the solutions scale with Bcr. Therefore, the equations need to be solved for one value of Bcr only. Since only one eruption is allowed per time step, the dependence of the solutions on Δt needs to be studied. Let Ft be an arbitrary numerical factor (= 3 for example) and compare the solutions of the equations for (Bcr, Δt) and (Bcr, Δt/3). It is clear that there will be 3 times as many eruptions in the second case (with the shorter time step) than in the first case. However, if the erupted flux in case one is multiplied by 3, then the solutions for this case become nearly identical to those of case two (Δt is shorter than any typical time of the system, and the difference due to the unequal time steps is negligible). Therefore, varying the time step is equivalent to keeping Δt fixed while multiplying the erupted flux by an appropriate factor. In the numerical calculations Δt was set equal to 105 s. The factor Ft can then be interpreted as the number of eruptions per 105 s. The integration of the equations shows that there is a transition in the nature of the solutions for Ft ≈ 2.5. For Ft 2.5, the eruptions occur for θ greater than ≈ π/4, where θ is the polar angle. Furthermore, for Ft 2.5. The factor Ft is an arbitrary parameter in the model and an appeal to observations is necessary. We set Bcr = 103 G. In the model, the magnetic flux of erupting magnetic tubes, is then about 3 × 1021 G, of the order of the solar values. For this value of Bcr and for the value of Ft (≈ 2.5) at which the transition takes place, the total erupted flux in 10 years is about 0.85 × 1025 Mx in remarkable agreement with the total erupted flux during a solar cycle. Concerning the dynamo models studied here, a major drawback encountered in previous papers has been the eruptions at high latitudes, which entail unrealistically large values for the radial magnetic field at the poles. The results of this paper provide a major step forward in the resolution of this difficulty.

Short-channel GaN/AlGaN doped channel heterostructurefieldeffect transistors with 36.1 cutoff frequency

The authors report on the improved microwave performance of short AlGaN/GaN doped channel heterostructure field effect transistors. These transistors with 0.25 µm gates have a cutoff frequency fT up to 36.1 GHz (the highest reported value for a wide-bandgap semiconductor) and a maximum oscillation frequency fmax ≃ 70.8 GHz. This value of fT is the highest value reported for any wide-bandgap semiconductor device.

A schedule induction probe technique for evaluating abuse potential: comparison of ethanol, nicotine and caffeine, and caffeine-midazolam interaction.

Previous research has shown that under daily 3h sessions of food schedule-induced drug solution polydipsia (on a fixed-time 1min (FT 1min) schedule, session probes at greater FT values induced comparatively more ml/pellet drinking of solutions of drugs possessing abuse potential (ethanol, cocaine, midazolam) than of vehicle or other drug solutions. The present study extended these findings to nicotine and caffeine, drugs that usually do not function as reinforcers in i.v. self-administration studies with animals, but are known to have reinforcing effects for humans. The positive effects for nicotine and caffeine did not depend upon prior overindulgence in ethanol. Results on the effects of chronic, presession s.c. doses of midazolam could not be interpreted as contributing to the abuse potential of caffeine, but had independent dipsogenic effects. The FT probe technique, as well as schedule-induced i.v. self-administration, are useful methods for discerning the abuse potential of agents which are usually not distinguished by i.v. self-administration methods.

The influence of horizontal circulation on the supply and distribution of tracers

A theoretical analysis of the mixing associated with (horizontal) advection and dispersion is used to show that the larger scale, longer-term distribution of conservative tracers in the southern North Sea is primarily determined by the residual circulation pattern. Model estimates of this circulation have been substantiated from new year-long high-frequency radar monitoring of flow through the Dover Strait. Model simulations of the saline balance and for the dissolved metals Cd, Cu, Pb, Zn and Ni are made for the North Sea Project (NSP) survey period, using river and atmospheric inputs specified from the 1987 Quality Status Report. Computed concentrations are in reasonable agreement with measured values (except for lead where losses by rapid adsorption were not included in the model). The flushing time, F T , of the southern North Sea (to 56° N) is approximately 240 days. For any conservative tracer and this value of F T , the observed seasonal amplitude in concentration corresponding to a seasonal inflow I cos wt is only 0.23 of the steady concentration corresponding to a continuous inflow I . By contrast with the above responses for ‘conservative’ tracers entering from rivers or adjacent seas, concentrations of certain ‘non-conservative’ tracers can be almost entirely determined by localized exchange processes. Thus the spatial pattern of seasonal variability in temperature and dissolved oxygen is shown to be closely correlated with the inverse of water depth. For such tracers, the influence of advection is small and generally confined to coastal or stratified waters. For shorter term processes, this influence of advection is further reduced. The transport of suspended sediments is highly dependent on particle size. While the transport of fast-settling sediments is complicated by periodic episodes of settlement and re-suspension, transport of slow-settling sediments (the main agent for adsorbed contaminants) approximates that of a dissolved tracer. Thus, to first order, simple models incorporating residual advection are adequate to relate inputs to concentrations (averaged over appropriate time and length scales) for reasonably conservative dissolved tracers. Likewise point-models are often adequate to study processes fundamentally concerned with vertical exchange rates particularly for shorter-term processes in well-mixed waters away from the coastal zone.

Reply by Authors to F. B. Gessner and M. A. Leschziner

which agree reasonably well with the normalized_stress levels measured byjChampagne, Harris, and Corrsin (w//: = 0.93, vi/k = 0.48, w/k= 0.59, -~uv/k=0.33). Finally, it should be noted that if the suggested alternate value for fa is adopted, then ft will be lower by a factor 2.5 than the value of ft specified by the authors. In reference to Eq. (4), this change will diminish the effect of swirl on the eddy viscosity and, in turn, will alter predictions in comparison to those shown in Figs. 1-3 of Ref. 1. It would be informative if the authors were to repeat their calculations in order to demonstate the performance of their model when referred to a value of ft that is internally consistent with the overall model.

Hormonal diagnosis in so-called androgenetic alopecia in the female

Androgenetic alopecia (a.A.) occurs quite frequently. Up to 79% of women suffer at least temporarily from varying degrees of intermittent diffuse hair loss in the centro-parietal and/or fronto-temporal regions. A.A. is caused by an androgen excess acting on the hair follicle for prolonged periods of time in the presence of a genetic predisposition. However, often hyperandrogenemia cannot be demonstrated in such patients. 125 women with clinically typical a.A. were investigated prospectively under standardized conditions. Patient age ranged from 18 to 68 years (mean +/- SD: 34 +/- 11.6). Atypical uterine bleeding such as menorrhagia, hypermenorrhea and polymenorrhea were found in 69 women. The hair loss varied between 50 and 400 hairs per day (124 +/- 125). Additional signs of hyperandrogenism, i.e. seborrhea (n = 83), acne (n = 52) and hirsutism (n = 28), were often observed. Basal levels of total and free testosterone (T and FT), dihydro-T (DHT) DHEA-sulfate (DS), delta 4-androstendione (A), 17 alpha-hydroxy-progesterone (17P), cortisol (F), progesterone (P), 17 beta-estradiol (E2), sex hormone binding globuline (SHBG), prolactin (PRL), thyreoidea-stimulating hormone (TSH), ferritin (Fe), vitamin B12 (B12) and folat (Fo) were determined by RIA. FT was also measured by equilibrium dialyses. Different methods of determining bound and unbound T were used; their diagnostic value is discussed in detail. In addition, a combined ACTH/TRH-stimulation test was performed in all patients. Pathologic changes of one parameter were detectable in 26.4% of patients, while 67.2% revealed deviations of two or more indices. Excluding clinically relevant borderline values, only 6.4% of patients were without any abnormalities. The incidence rate of pathologic parameters was as follows: FT in % = 52%, Fe = 42%, PRL = 34%, E2 = 34%, FT in pg = 29%, DHT = 28%, SHBG = 26%, TSH = 20.8%, DS = 19%, T = 14%, 17P = 11%, Fo = 7%, A = 6%, F = 6%, B12 = 5%. Group and individual case analyses revealed significant correlations between (1) the levels of the various androgens, PRL and TSH and (2) the E2, SHBG and FT values; these, in turn, were correlated to (3) the occurrence of certain bleeding anomalies (amount, duration, interval) and corresponding ferritin deficiency. Therapy was directed at normalizing the disturbed estrogen-androgen-balance. Using low-dose antiandrogens, estrogens, prolactin suppressants, corticoids, iron-II-preparations as well as estrogen-containing hair lotions hair loss was arrested in 74 of 104 treated women, while regrowth of hair was accomplished in 16 patients. 14 women did not respond to therapy.

Radiative corrections to 0+-0+ beta transitions.

We reexamine and refine our former analysis of electromagnetic corrections to ${0}^{+}$-${0}^{+}$ \ensuremath{\beta} transitions. The disagreement with a recent approximate calculation of Sirlin and Zucchini is due to an error in our earlier numerical computation. The new results lead to much better agreement between the Ft values of the eight accurately studied decays. We find an average value of Ft =3072.4\ifmmode\pm\else\textpm\fi{}1.6 s..AE

DC and microwave characteristics of an In 0.53 Ga 0.47 As/In 0.52 Al 0.48 As modulation-doped quasi-MISFET

The DC and microwave performance of a modulation-doped InGaAs/InAlAs quasi-MISFET structure, grown by molecular beam epitaxy, is reported. Improved performance is obtained with the incorporation of Ti in the source-drain metallisation with which contact resistances as low as 0.1 Ωmm are measured. An extrinsic transconductance of 310mS/mm and a best value of fT=32 GHz in a 1.0 μ-gate device are measured at 300 K.

6He β-decay from a three-body model of the A=6 system

The rate of 6He β-decay is computed from 6He and 6Li separable-potential three-body wave functions. The value of ft predicted with the wave functions derived from the most complete set of αN and NN interactions is 807±12 s compared to the experimental value of 807±2 s.

Plasma amino acid patterns during supplemental intravenous nutrition of low-birth-weight infants

In 42 low-birth-weight infants (smaller than 1,200 gm), we have compared the effects of intravenous nutrition supplement versus conventional feedings on growth, morbidity, mortality, and plasma amino acid patterns. Despite similar total caloric intake in INS and control groups, weight gain was greater in the INS infants. The overall mortality rate did not differ in the two groups. Nonsurviving infants receiving INS lived longer (mean equal to 30 days) than nonsurviving CON infants (mean equal to 5 days). Complications were equally frequent in both groups except that hyperglycemia occurred more often in infants receiving INS. The plasma aminogram of the LBW infant is described and compared to those of the full-term infant and adult. Hypoaminoacidemia was present at birth in the LBW infants, concentrations of glutamine, alamine, glycine, histidine, and ornithine being significantly (P smaller than 0.05) below FT values. During INS, elevations of threonine, serine, and methionine above FT values occurred. Glutamine remained subnormal despite INS. Recommendations for an INS solution more suitable for use in LBW infants are presented.

Fall-off of base component of FTat low currents in a bipolar transistor

Abstract The injection of carriers from the emitter periphery to the collector creates a lateral charge adjacent to the active region. In the presence of emitter current crowding the lateral charge can become a significant fraction of the total base charge and hence reduce the value of FT

A NOTE FOR SOLVING THE EXPRESSION EQUATION BY THE METHOD OF MOMENT

In the previous report3) the method of moment was employed to solve the basic differential equation of forced expression. No explanation, however, was given as to the validity of using the larger root β for the non-dimensional critical time θCri. It is shown in this complementary report that theoretically the value of ft is restricted to the larger root of Eq. (17)3) with the range of o Some comments on the diffusion process with different boundary conditions are also given.

Alpha particles following the β-decay of 12B and 12N

The 10.3±0.3 MeV state in 12C, populated by the β-decay of 12B and 12N, decays by α-particle emission to the ground state of 8Be; its width is 3.0±0.7 MeV. The population and decay of the 10.3 MeV state limit the spin to J π = 0 + or 2 +. The 12.7 MeV state in 12C, populated by the β-decay of 12N, decays by α-particle emission to the J π = 2 + first excited state of 8Be. The formation and decay of the 12.7 MeV state uniquely determine the spin as J π = 1 +. The estimated value of log ft = 3.7 +0.3 −0.5 for the β-decay of 12N to the 12.7 MeV state suggests that this state is closely related to the 12N ground state.

Measurement of circular polarization of γ-quanta accompanying La140 β-decay

The (βγ) circular polarization correlation is measured in La 140 by selection of γ-quanta with energy of 1.6 MeV and β-spectrum electrons with an upper limit of 2.2 MeV in La 140 . The resulting correlation coefficient is ω = + 0.15±0.09. Analysis of experimental data warrants the conclusion that the high value of log ft in the β-transition 3 − →2 + of La 140 is due to the cancellation of nuclear matrix elements. The relative quantity of the relativistic matrix elements is estimated.

On the gamma rays emitted in the decay of 59 140 Pr

The γ-rays from140Nd-140Pr mixture have been studied in a scintillation spectrometer. The new γ-rays of energies (900 ±20), (1600±30) and (2500 ±50) keV have been detected and their intensities in comparision to the 511 keV annihilation radiation are (0.15±0.05)%, (0.50±0.10)% and (0.02±0.01)% respectively. The branching ratio from the decay of140Pr to the ground state, 1 600 keV state and 2500 keV state of140Ce have been estimated, from the photon intensities, to be 99%, ∼1% and ∼0.2% respectively giving the value of log ft∼5 for all these branches. An assignment of 1+ for140Pr is suggested.

Societies and Academies

Societies and Academies