scholarly journals A series acceleration algorithm for the gamma-Pareto (type I) convolution and related functions of interest for pharmacokinetics

2021 ◽  
Author(s):  
Carl A. Wesolowski ◽  
Jane Alcorn ◽  
Geoffrey T. Tucker
Keyword(s):  
Power Function ◽  
Intravenous Injection ◽  
Computer Code ◽  
Type I ◽  
Long Run ◽  
Practical Research ◽  
Sums Of Exponentials ◽  
Series Acceleration ◽  
Kinetics Of ◽  
Better Than

Abstract The gamma-Pareto type I convolution (GPC type I) distribution, which has a power function tail, was recently shown to describe the disposition kinetics of metformin in dogs precisely and better than sums of exponentials. However, this had very long run times and lost precision for its functional values at long times following intravenous injection. An accelerated algorithm and its computer code is now presented comprising two separate routines for short and long times and which, when applied to the dog data, completes in approximately 3 min per case. The new algorithm is a more practical research tool. Potential pharmacokinetic applications are discussed. Graphic abstract

Cellular studies of peripheral neurons in siphon skin of Aplysia californica

1979 ◽  
Vol 42 (2) ◽  
pp. 530-557 ◽  
Author(s):  
C. H. Bailey ◽  
V. F. Castellucci ◽  
J. Koester ◽  
E. R. Kandel
Keyword(s):  
Motor Neurons ◽  
Synaptic Input ◽  
Firing Pattern ◽  
White Cell ◽  
Type I ◽  
Type Ii ◽  
Peripheral Neurons ◽  
Peripheral Neuron ◽  
Type I Neuron ◽  
Kinetics Of

1. To account for the similarity in the kinetics of habituation between the central and peripheral components of siphon withdrawal, we have tested the idea (52) that each centrally located mechanoreceptor sensory neuron sends two branches to siphon motor neurons; one to centrally located siphon motor neurons and a collateral branch that remains in the periphery and innervates the peripheral siphon motor neurons. 2. We have found a group of peripheral siphon motor neurons and tested the connection onto these cells by central mechanoreceptors. In addition, we have defined by various electrophysiological and morphological criteria two general classes of peripheral neurons that lie along the course of the siphon nerve. 3. One class (type I) consists of only a single cell in each animal. This peripheral neuron typically has the largest cell body found lying along the siphon nerve and is the only peripheral nerve cell that appears white when viewed under epi-illumination. The type I neuron often has a highly regular firing pattern, which occurs in the absence of spontaneous synaptic input. The three-dimensional morphology of this neuron suggests a paucity of fine processes, most of which do not arborize and may terminate in the connective tissue sheath. Fine structural observations of the peripheral white cell have revealed the presence of large densecore granules. The peripheral type I neuron is similar in most of its electrophysiological and morphological properties to central neurons postulated to be neurosecretory. The peripheral white cell is, at present, the only peripheral neuron we can identify with certainty as a unique individual. 4. The second class (type II) of peripheral neurons are siphon motor neurons for the peripheral component of the siphon-withdrawal reflex. In contrast to the type I neurons, members of the second class of peripheral neurons possess smaller, more spherical cell bodies that have varying amounts of orange pigmentation and which give rise to a relatively well-developed and arborized dendritic tree. Type II neurons feature an irregular spontaneous firing pattern that is occasionally modulated by a rich spontaneous synaptic input. Peripheral siphon motor neurons have restricted motor fields that produce contraction of the mantle floor and the base of the siphon. Most of the type II neurons were found to be electrically coupled to one another. 5. The peripheral siphon motor neurons resemble the central siphon motor neurons in that they receive a collateral synapse from centrally located mechanoreceptor sensory neurons. This peripheral sensory-to-motor synapse exhibits the same kinetics of decrement as its central counterpart, both of which parallel behavioral habituation. 6. The rich mechanoreceptor input onto the relatively isolated dendritic trees of the peripheral siphon motor neurons provide a uniquely restricted neuropil to study the sensory-to-motor synapse. The peripheral motor neurons may, therefore, be a useful simple preparation for the cellular study of behavioral plasticity.

A bivariate optimal replacement policy for a repairable system

1994 ◽  
Vol 31 (4) ◽  
pp. 1123-1127 ◽  
Author(s):  
Yuan Lin Zhang
Keyword(s):  
Explicit Expression ◽  
Average Cost ◽  
Replacement Policy ◽  
Repairable System ◽  
Optimal Replacement ◽  
Long Run ◽  
Optimal Replacement Policy ◽  
Working Age ◽  
Better Than

In this paper, a repairable system consisting of one unit and a single repairman is studied. Assume that the system after repair is not as good as new. Under this assumption, a bivariate replacement policy (T, N), where T is the working age and N is the number of failures of the system is studied. The problem is to determine the optimal replacement policy (T, N)∗such that the long-run average cost per unit time is minimized. The explicit expression of the long-run average cost per unit time is derived, and the corresponding optimal replacement policy can be determined analytically or numerically. Finally, under some conditions, we show that the policy (T, N)∗ is better than policies N∗ or T∗.

Etude par spectrométrie infrarouge de l'action de solvants aprotiques sur l'association ester–eau et ester–Ba2+. Discussion du rôle catalytique du solvant et de l'ion Ba2+ dans l'hydrolyse alcaline du propionate de methyle

1979 ◽  
Vol 57 (4) ◽  
pp. 400-403 ◽  
Author(s):  
Anne Le Narvor ◽  
Pierre Saumagne
Keyword(s):  
Ir Spectra ◽  
Charge Density ◽  
Carbonyl Group ◽  
Alkaline Hydrolysis ◽  
Experimental Results ◽  
Methyl Propionate ◽  
Orbital Control ◽  
Different Types ◽  
Kinetics Of ◽  
Better Than

The ir spectra of mixtures of methyl propionate/water and methyl propionate/Ba2+ in dimethylsulfoxide and in acetonitrile have been recorded in the region of the νCO mode of the ester. Evidence is presented to indicate the presence of different types of complexes; their concentration was determined as a function of the composition of the medium. The spectroscopic results are compared to those from the kinetics of the alkaline hydrolysis in the same conditions. It is demonstrated that the orbital control explains the experimental results better than does the charge density on the carbon of the carbonyl group. [Journal translation]

Non-malignant gall bladder perforation: Our experience from an institution-based retrospective analysis of 25 cases

2021 ◽  
pp. 004947552110365
Author(s):  
Abhijeet Kumar ◽  
Nirmal Prasad Shah ◽  
Narendra Pandit ◽  
Suresh Prasad Sah ◽  
Rakesh Kumar Gupta ◽  
...  
Keyword(s):  
Computed Tomography ◽  
Gall Bladder ◽  
Clinical Presentation ◽  
Gallbladder Perforation ◽  
Type I ◽  
Computed Tomography Scan ◽  
Duration Of Hospital Stay ◽  
Symptoms And Signs ◽  
Tomography Scan ◽  
Better Than

Gallbladder perforation still continues to perplex surgeons; 25 such patients diagnosed either pre- or intra-operatively and managed at our institute over the last 10 years period were analysed. Only eight were diagnosed pre-operatively, while a large majority (17) had a wrong initial working diagnosis. Symptoms and signs were variable. No blood investigation was specific. A computed tomography scan was generally better than ultrasound in detecting the perforation. All our cases were managed operatively with no mortality and a mean duration of hospital stay of 6.8 days. Most perforations were extra-hepatic (84%) and those of Niemeier’s type I (52.2%). Because of its varied clinical presentation, gallbladder perforation is often an intra-operative diagnosis, but early intervention carries a good outcome.

The absorption spectra of irradiated diamonds after heat treatment

1956 ◽  
Vol 237 (1208) ◽  
pp. 75-89 ◽  
Keyword(s):  
Absorption Spectra ◽  
Absorption Lines ◽  
Type I ◽  
Type Ii ◽  
Large Reduction ◽  
Isothermal Heating ◽  
Interstitial Carbon ◽  
Crystal Imperfections ◽  
Continuous Absorption ◽  
Kinetics Of

The absorption spectra of eight type I and three type II a diamonds irradiated with neutrons, electrons or y-rays have been recorded at 80 and 290°K after various heat treatments in the temperature range 0 to 900°C. It is found that heating in the range 350 to 450°C causes a general reduction in the irradiation-induced absorption owing to the recombination of those interstitials and vacancies which are near neighbours. Heating type II a diamonds at 600°C causes a large reduction in the irradiation-induced lines and new lines appear. These are probably due to pairs of identical defects, and the kinetics of their formation during isothermal heating at 600°C are presented. At higher temperatures all absorption lines in type II a diamonds disappear and only continuous absorption remains. This is probably due to amorphous or graphitic regions produced by agglomeration of defects. Type I diamonds show the same kind of absorption, but in addition show an increase in strength of the natural lines and also some new absorption lines which are not removed by heating at 900°C. It is suggested that these additional processes are due to the anchoring of vacant atomic sites and interstitial carbon atoms at crystal imperfections present only in type I diamonds.

scholarly journals Maintenance treatment of diabetic patients, associating arterial obstructive tibio-peroneal disease

1995 ◽  
Vol 113 (1) ◽  
pp. 701-705
Author(s):  
Nelson Wolosker ◽  
Ruben Miguel Ayzin Rosoky ◽  
Baptista Muraco Neto ◽  
Berilo Langer
Keyword(s):  
Maintenance Treatment ◽  
Diabetic Patients ◽  
Type I ◽  
Group I ◽  
Significant Difference ◽  
Therapeutic Procedures ◽  
Arterial Pulsation ◽  
Group A ◽  
Group B ◽  
Better Than

When a melito-diabetic patient presents trophic infected injury on the limb, it is essential an evaluation of the circulatory conditions for therapeutic procedures orientation. In some circumstances, although arterial pulsation is absent, there is no ischemia of tissues. In these cases, the maintenance treatment, with eventual resection of the necrosed and infected tissues may be adopted. Evolution of 70 diabetic patients with trophic injuries on extremities were submitted to a maintenance treatment. Age of patients varied from 28 to 88 years, with an average of 56.8. The most occurrence was verified in women, with 42 cases. Diabetes non-dependant on insuline (type II) was observed in 64 patients (91.5%), being the remaining 6 patients of type I. Diabetic retinopathy was observed in 14 (20%) of the patients, neuropathy in 22 (31%) and nephropathy in 8 patients (11.4%). All the patients presented arterial pulsation until the popliteal region. They were divided in 2 groups, considering trunk arteries of legs: Group I, pervial legs arteries, composed by 48 patients; Group II, occluded legs arteries, with 22 patients. In what refers to the anatomic local of the injuries, patients were classified in three groups: Group A, formed by 32 patients (45.7%), presenting injuries in one or two toes only, without affecting the metatarsic region; Group B, formed by 16 patients (22.9%), trophic injuries affecting the metatarsic region and Group C, formed by 22 patients (31.4%), injuries affecting the calcaneous region. Injuries in both of the groups were caused by mechanical traumatism. Duration of the injury in the inferior member varied from 7 to 48 days, resulting in a 12 days average. Analyzing pervicacity in trunk arterias and evolution of patients, it may be observed that there has been a significantly better result in those with all the pulses present (81.3% x 45.5%)(p<0,01). Studying the injury locals associated to the evaluation of the cases, we may observe that for injuries in the extreme digital, result is significantly better than in locals more nearly. When distal pulses are absent, there is no significant difference in the result of the treatment, being performed in distal injuries or in the more near ones (p>0,05)(Table IV).

scholarly journals Tenure, Faculty Contracts and Bargaining Conflict

2017 ◽  
Vol 28 (3) ◽  
pp. 47-70
Author(s):  
Derek Hum
Keyword(s):  
Opportunity Cost ◽  
Research Output ◽  
Job Security ◽  
University Administrators ◽  
Government Grants ◽  
Faculty Unions ◽  
Long Run ◽  
Academic Employment ◽  
The University ◽  
Better Than

Tenure is sometimes charged as giving faculty lifetime job security, with little accountability and sporadic monitoring of performance. Scholars have traditionally defended tenure as necessary for academic freedom. This paper takes a different approach by examining the academic "employment contract relationship," and explaining how tenure can lead to bargaining conflict. Tenure is costly to the university but extremely valued by the faculty member. The opportunity cost of granting tenure to someone is the lost teaching and research output of younger people who cannot be hired in future. Tenure is necessary because without it, incumbents would never recommend hiring people who might be better than they are, for fear of being replaced. Tenure is also efficient because faculty have better information about incumbents than either university administrators or outside consultants. Tenure is therefore necessary to motivate older faculty to hire the best. With staff budget dollars able to be shifted back or forwards across time periods, tenure secures the truthful revelation of who are the good candidates over all periods, and the university is guaranteed that those who are in the best position to judge (namely, faculty rather than administrators) have every incentive to make the best decisions. It follows, then, that the naive suggestion to get rid of tenure so that older, expensive professors can be fired and replaced with younger, cheaper professors would be disastrous in the long run. A simple model is presented explaining why (a) recent cutbacks in government grants, (b) cost pressures on university budgets, (c) limits to tuition increases, and (d) declining interests in attending a less "excellent" university have all resulted in pressure on tenure. Because there is no previously agreed-to mechanism in place to adjust staff, university administrations and faculty unions are not so much bargaining over an acceptable contract outcome as they are contesting the very rules of the bargaining game. Accordingly, unless tenure is reconsidered, universities may increasingly face bargaining conflict. Tenure could be reformed by making the term of tenure limited but related to rank, and establishing a maximum eligibility period during which a faculty may apply for promotion.

scholarly journals Hydrodynamics characteristics of the small ships rudders

2020 ◽  
Vol 43 ◽  
pp. 21-26
Author(s):  
Dan Obreja
Keyword(s):  
Design Process ◽  
Computer Code ◽  
Short Description ◽  
Research Centre ◽  
Research Activities ◽  
Optimum Position ◽  
Practical Research ◽  
Small Ship ◽  
Control Forces ◽  
Selection Of

The estimation of the hydrodynamics characteristics of the small ships rudders is an important issue in the initial design process. The manoeuvring performance depends on the type and geometry of the rudder. The control forces and moments generated by the rudder deflection can be calculated on the basis of the hydrodynamics characteristics of the rudder. A short description of the Mordvinov theoretical model is presented in this paper, in order to determine the hydrodynamics characteristics of a small ship rudder, with the propeller and hull influences. On the basis of the control forces and moments, the optimum position of the rudder stock and the selection of the steering gear can be performed. Using the Mordvinov method, the computer code PHP NM-MAN-HC was develop at the Research Centre of the Naval Architecture Faculty of “Dunarea de Jos” University of Galati. This computer code is integrated in the software platform PHP (Preliminary Hydrodynamics Performance) and is used for didactic applications and practical research activities in the small ship design process

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