scholarly journals VI. Experiments upon the heart of the dog with reference to the maximum volume of blood sent out by the left ventricle in a single beat and the influence of variations in venous pressure, arterial pressure, and pulse-rate upon the work done by the heart

1884 ◽  
Vol 175 ◽  
pp. 139-160 ◽  

The most important factor to be determined before calculating the work done by the heart is the quantity of blood forced from the ventricles at each systole. Most of the efforts to determine this quantity have been based either upon faulty observations upon the dead heart, or upon the uncertain data obtained by estimating the mean velocity of the stream of blood in the aorta. Professor Martin accordingly suggested to us that we should attempt to measure it directly on the isolated Dog’s heart. The work thus undertaken was carried on during the greater part of the university session, 1881-82, and the results obtained are given in the following pages. The method of isolating the heart was essentially that described in Professor Martin’s paper (Phil. Trans., 1883, p. 663). In the course of this work many unexpected difficulties arose, necessitating changes in the apparatus and the method of operating, and preventing us for a long time from obtaining any successful results. In our experiments it was necessary not only that the heart should live and beat, but that it should be in the best possible physiological condition, and any marked pulmonary œdema made an experiment nearly valueless. This most frequent cause of failure was mainly owing to the fact that, on account of the large quantity of blood required for an experiment, we were obliged to use Calf’s blood obtained from the butcher; very often this blood, as Professor Martin states in his paper, will bring about œdema of the lungs in a short time; large quantities of exuded serum pour out of the tracheal cannula, the air-passages in the lungs become choked up with liquid, and the circulation from the right to the left side of the heart is greatly impeded. We have succeeded, however, in making a considerable number of experiments in which all the conditions were favourable, the œdema of the lungs not occurring to any marked extent until after many observations had been made.

1883 ◽  
Vol 35 (224-226) ◽  
pp. 271-274

Owing to the indirectness of the methods hitherto used for estimating the quantity of blood pumped out from the left ventricle at each systole, this important factor in all calculations of the work done by the heart has never been satisfactorily determined. Of the later physiologists who have investigated the subject, Volkmann and afterwards Vierordt, from calculations based upon the mean velocity of the stream of blood in the unbranched aorta, obtained the fraction 1/100 as representing the ratio of the average weight of blood ejected at each systole of the left ventricle to the weight of the whole body. Fick, from data obtained by placing the arm in a plethysmograph, and estimating the velocity of the stream of blood in the axillary artery from the increase in volume of the whole arm at each systole of the heart, arrived at a much smaller fraction, about 1/1000 for the ratio between the weight of blood thrown out at each systole and the body weight.


Author(s):  
Heni Sulistiani ◽  
Ahmad Ari Aldino

In pandemic era, almost everyone struggles for their life. College students are such example. They have difficulty in paying tuition fee to continue their study. Based on this problematic situation, Universitas Teknokrat Indonesia grants the students who have good academic performance with tuition fee aid program. Many variables used for determining the grant made it hard to make a decision in a short time or even takes very long time. To make it easier for management to decide who is the right student to get grant, it needs classification model. The purpose of this study is the classification of grant recipients by using decision tree C4.5 algorithm. That can determine whether a potential student can be accepted as an awardee or not. Then, the results of the classification are validated with ten-fold cross validation with an accuracy, precision and recall with the score of 87 % for all part. It means the model perform quite well to be implemented into system.


1977 ◽  
Vol 83 (3) ◽  
pp. 529-546 ◽  
Author(s):  
M. W. Reeks

A solution to the dispersion of small particles suspended in a turbulent fluid is presented, based on the approximation proposed by Phythian for the dispersion of fluid points in an incompressible random fluid. Motion is considered in a frame moving with the mean velocity of the fluid, the forces acting on the particle being taken as gravity and a fluid drag assumed linear in the particle velocity relative to that of the fluid. The probability distribution of the fluid velocity field in this frame is taken as Gaussian, homogeneous, isotropic, stationary and of zero mean. It is shown that, in the absence of gravity, the long-time particle diffusion coefficient is in general greater than that of the fluid, approaching with increasing particle relaxation time a value consistent with the particle being in an Eulerian frame of reference. The effect of gravity is consistent with Yudine's effect of crossing trajectories, reducing unequally the particle diffusion in directions normal to and parallel to the direction of the gravitational field. To characterize the effect of flow and gravity on particle diffusion it has been found useful to use a Froude number defined in terms of the turbulent intensity rather than the mean velocity. Depending upon the value of this number, it is found that the particle integral time scale may initially decrease with increasing particle relaxation time though it eventually rises and approaches the particle relaxation time. It is finally shown how this analysis may be extended to include the extra forces generated by the fluid and particle accelerations.


Author(s):  
Phan Xuan Binh ◽  
Nguyen Minh Ha

The most important determinant of organizational effectiveness is the ability to attract, hire, and develop capable talent. The ability to attract and retain superior employees can lead to sustained competitive advantage for organizations. This is difficult due to the shrinking availability of qualified labor. The use of recruitment agency (RA) or employment agency allows human resource departments to target and identify quality candidates with more efficiency. RA, kind of consultancy, is normally understood as third party recruiter that finds jobs for people seeking them and finds people to fill particular jobs3 . Some RA focus their efforts on executive, managerial, and professional positions (white and yellow collar workers). These firms are split into two groups: (1) contingency firms that charge a fee only after a candidate has been hired by a client company and (2) retainer firms that charge a client a set fee whether or not the contracted search is successful. Most of RA in Vietnam apply contingency basis. Majority of foreign and big local companies use RA as one of the key recruitment sources to attract middle to senior level employees despite there is maybe higher expenses of this source than using other recruitment sources in some extents below: • The job vacancy is top confidential and recruiter cannot launch the public recruitment • The vacancy requires very short time to fill • The limited staffing resources of recruiting department or • The limited candidate pool in some industries or function which may cause very long time to fill the vacancy or to find out the right candidate.


PEDIATRICS ◽  
1992 ◽  
Vol 89 (3) ◽  
pp. 506-508
Author(s):  
THOMAS R. LLOYD ◽  
RICHARD L. DONNERSTEIN ◽  
ROBERT A. BERG

Central venous pressure measurements in the abdominal inferior vena cava were compared with measurements in the right atrium in 10 infants and 10 children during cardiac catheterization. At end expiration, the mean pressures at these two sites were within 1 mm Hg of each other in all 20 patients, with a mean difference of 0.0 ± 0.36 mm Hg. The abdominal inferior vena cava is a safe and convenient site for measurement of central venous pressure, and our study confirms that such measurements are accurate.


Blood ◽  
2005 ◽  
Vol 106 (11) ◽  
pp. 952-952 ◽  
Author(s):  
Robert J. Adams ◽  
Julio Barredo ◽  
Duane R. Bonds ◽  
Clark Brown ◽  
James Casella ◽  
...  

Abstract Transcranial Doppler (TCD) is useful in children with sickle cell anemia (SCA) to detect increased risk of stroke. The use of TCD in infants less than 2 years of age is less well established, but has previously been shown to be feasible. As a secondary endpoint in the BABY HUG Trial, TCD is expected to provide useful information on the possible effects of hydroxyurea (HU) in babies with SCA. BABY HUG is an NHLBI-NICHD sponsored phase III clinical trial to compare hydroxyurea to placebo to ascertain effectiveness in preventing end organ damage of the spleen and kidney. Eligible subjects underwent a baseline TCD using the Nicolet Companion (EME) 2-MHz pulsed Doppler. All infants were 8–18 months of age at enrollment, had no history of stroke and were not receiving chronic blood transfusions. Blood flow velocities were recorded using the Stroke Prevention Trial in Sickle Cell Anemia (STOP) protocol with the exception of reducing the standard sample volume to 4 mm. No sedation was used. The time averaged maximum mean was measured to determine the highest velocity on either side to categorize the study as normal (all recordings <170 cm/sec), conditional (170–199cm/sec) or abnormal (≥200 cm/sec). Recordings of the middle cerebral artery (MCA) and internal carotid artery (ICA) bifurcation defined an adequate TCD. TCD was not required for study entry but subjects with an abnormal exam were not eligible for randomization and treatment. TCD exams were read by blinded reviewers at the Medical College of Georgia. TCD results were transmitted to Clinical Trials & Surveys Corporation (C-TASC) for statistical analysis. As of June 24, 2005, 70 TCD exams had been attempted. Two exams were unsuccessful (no data) because of the children’s irritability and 1 was interpreted as inadequate. Of the remaining 67 TCD exams, 66 were normal and one baby had a high conditional TCD (190 cm/sec). No subjects were found ineligible for the study due to TCD results. The mean velocity of the left MCA was 117 cm/sec ±22.9 and that of the right MCA was 114 cm/sec ±24.9. Regression analyses were performed to examine the relationship of maximum flow velocity (VMAX) to age and total hemoglobin (Hb). VMAX was inversely correlated to Hb (left p=<0.0001, right=<0.0014) and directly associated with age (left p=<.0005, right p=<0.0022). When the mean MCA velocity was regressed against age and Hb, both age (p=0.0285) and Hb (p=.0024) were significant. Adequate baseline TCD evaluation was obtained on 67 out of 70 babies. As expected, baseline TCD velocities varied inversely with the degree of anemia and directly with age; all but one was normal by childhood sickle cell disease standards. These studies provide valuable normative data for infants with SCA, and for further assessment of the effect of HU on TCD in infants with SCA as the study progresses.


1971 ◽  
Vol 8 (12) ◽  
pp. 1553-1583 ◽  
Author(s):  
R. F. Mereu ◽  
G. Jobidon

A major structural feature 50 to 75 km in width has been outlined along the Moho in an area just south of the Grenville Front from a delay-time analysis of Pn waves arriving from a number of different azimuths. The crust in this anomalous region was found to be from 5–10 km thicker than in the surrounding area. The low frequency portion of the gravity low in central Quebec can be attributed to this feature. The fact that the front is deep-seated suggests that it may mark the position of an ancient fault connected tectonically in origin to the mid-continent gravity high and Lake Superior syncline.During the summer of 1968, the University of Western Ontario participated with the Dominion Observatory of Canada and other research groups in a crustal survey of eastern Quebec. Shots of various sizes were fired by the Dominion Observatory at six different locations in central Quebec. Two of the locations were in the Superior (structural) Province, two in the Grenville (structural) Province, and two in the vicinity of the Grenville Front. The University of Western Ontario recording stations were located at distances from 60 to 800 km southwest of the shots and lay along (a) a 550-km long line running perpendicular to the Grenville Front from Lake Evans in the Superior Province to a point just south of Lake St. John in the Grenville Province, (b) a 100-km long line running parallel to the Grenville Front from Chibougamau to the northeastern end of Lake Mistassini. Six portable seismic recorders (two of them 3-component) were moved every day. A total of 45 locations were occupied, with observations being made in a fan-like manner.The apparent crust and upper mantle velocities as determined by a least squares analysis of all the data are 6.43 ±.03 km/s (43 observations) and 8.15 ±.03 km/s (70 observations) respectively. From an analysis involving combined seismic and gravitational observations along with synthetic seismograms, the following structure emerges. The mean velocity of the upper crust is 6.31 km/s, but because of the lateral variations in its structure the true velocity varies from 6.1 to 6.6 km/s, the higher values occurring just south of the Grenville Front. No clear evidence for layering could be found throughout the crust, but both seismic and gravitational observations indicated that the mean velocity of the lower portion of the crust was 6.55 km/s with this value increasing to at least 7 km/s just above the Moho. The apparent velocities of smaller regional samples of Pn observations varied erratically as a result of topography on the Moho. However values obtained from arrays oriented parallel to the Grenville Front were significantly higher, indicating that the upper mantle may be behaving in an anisotropic manner.


2000 ◽  
Vol 408 ◽  
pp. 323-345 ◽  
Author(s):  
T. B. NICKELS ◽  
P. N. JOUBERT

This paper examines changes in the mean velocity profiles of turbulent boundary layers subjected to system rotation. Analysis of the data from several studies conducted in the large rotating wind tunnel at the University of Melbourne shows the existence of a universal linear correction to the velocity profile in the logarithmic region. The appropriate parameters relevant to rotation are derived and correlations are found between the parameters. Flows with adverse pressure gradients, zero pressure gradients and secondary flows are examined and all appear to exhibit the universal linear correction, suggesting that it is robust.


2017 ◽  
Vol 4 (1) ◽  
pp. 129
Author(s):  
Agnieszka Zięba

Józefat Zielonacki - A Forgotten Polish Romanist of XIX C. An Outline of a BiographySummaryJ. Zielonacki was born on 28 November 1818 in a village called Goniczki, situated the Grand Duchy of Poznan, which belonged to his family.He spent his childhood in his family estate. After completing education in schools in Trzemeszno and Poznan he studied in Berlin, where he graduated in 1845 and conferred a doctor degree (dr) in both laws. In 1848 (or 1849) he was qualified as an assistant professor (dr hab) at Wroclaw University, where he subsequently lectured the Roman law.In 1850 Prof. Zielonacki succeeded to be a head of the Roman law department at the Jagiellonian University.At that time Galicia was in the period of absolutist reaction after the People’s Spring, distinguished by the suppression of civil liberties and a regime of terror. The declaration of a state of siege on 10.01.1849 led to handing over a full authority to Austrian generals, subsequent military commanders of the country, to whose authority - legitimately and in practice - (in these circumstances) the Galician governor - Agenor hr. Goluchowski was - submitted. The University was in practice deprived of its autonomy; all important matters were meticulously directed and supervised by the central authorities in Vienna. Appointments to professorships depended exclusively on the Austrian Ministry of Education, which also examined in detail ‘the political conformity’ of each candidate. Prof. Zielonacki was put up as a candidate by the minister Leon hr. Thun, who wrote in the application to the Emperor about a “great talent” but also “unblemished political attitude” of the candidate.J. Zielonacki lectured the Roman law in Cracow for two years and a half - until the end of December 1852. He was popular amongst the students and was respected amongst scholars as an eminent expert of the Roman law.On 1.01.1853 - without giving any justification, Prof. Zielonacki was removed from the University together with the following Professors: A. Malecki, W. Pol, A. Z. Helcel. The reasons for the dismissal have not been fully explained; at present it is considered as a revenge of the authorities for “the national attitude of the university full of dignity and visible efforts to maintain the Polish character” or even “acts of terror”. The direct reason for dismissing the “inconvenient” Professors was a denunciation against Prof. Malecki and Prof. Pol (and possibly Kremer), which drew the attention of the police to the whole academic environment. The head of the police in Cracow - Carol Neusser - who was commissioned to check the grounds of the denunciation, invigilated all university professors. It was claimed in his report (written on 21.03.1852) that some of the lecturers were particularly dangerous for the authorities. Prof. Zielonacki was described to be an impulsive person, having - “apart from Polish revolutionary tendencies, plenty of Prussian prejudices against Austria”, behaving “always unfriendly” towards the government. Thus, the removal of the professors had a clear political context - no particular accusations were however formulated. After the dismissal from the Jagiellonian University, Prof. Zielonacki was moved to Innsbruck, where he was the head of the Roman law department (until 1855), and afterwards he took over the same post at the Karol University in Prague.In 1857 Prof. Zielonacki, at his own request, was moved to the Lwow University, where he taught Roman law until he retired in 1870.In 1861 he tried to go back to Cracow to take over a vacant post in the Roman Law department but the authorities rejected his candidacy.Prof. Zielonacki made major contributions to the polonization of the Lwow University - he was the first and - for a long time - the only professor lecturing in Polish. In intense disputes with German professors he managed to win the right to use the Polish legal terminology during the lectures, subsequently a right for lectures in Polish, and afterwards to use Polish during exams. Fighting for the polonization of the university had an impact on his professorship career - after he was elected to be the dean of the Law Faculty for the first time for the academic year 1861/61 - he was ostentatiously neglected by his colleagues in elections to this post.Prof. Zielonacki, apart from his work with students, was also active in other areas: between 1867 and 1873 he was a member of the Autrian State Tribunal, and above all an active member of the Science Academy (from 1873 - since it was established). After Prof. Kramers death, from 1875 to 1878, he was a director of the Philosophy and History Faculty and played a significant role in establishing the Commission of Law in the Science Academy.Prof. Zielonacki died in his family estate in Goniczki on 28.04.1884.His scientific output is very ample - he wrote numerous articles and dissertations (in Latin, German and Polish) mainly on possession and usucaption. He is also an author of two monographs on servitudes (Wroclaw 1849) and on possession (Poznan 1854). The latter was also issued in Polish. The work of his lifetime was a two pans manual “Pandekta, i.e. a lecture on the Roman private law as it is the basis of the new laws” published in Polish in Cracow (1862/63, issue II 1870/1871), dedicated to “Polish youth devoting to the legal profession”. This work was greatly appreciated at his times.At present Prof. Zielonacki is groundlessly forgotten. He belonged to the most eminent Romanists of his times, he was an expen in Latin and German literature on the Roman law. He also substantially contributed to the polonization of law teaching. His personage - as an eminent scholar and patriot - it worth recalling. 


2019 ◽  
Author(s):  
Rui Guo ◽  
Chaofeng Fan ◽  
Ruiqi Chen ◽  
Zhiyuan Yu ◽  
Rui Tian ◽  
...  

Abstract Background: Primary intraventricular hemorrhage is a rare type of stroke and little is known its causes, characteristics and outcomes in children. Methods: We retrospectively analyzed the clinical characteristics of patients aged one month to 21 years during seven consecutive years with primary intraventricular hemorrhage. Primary intraventricular hemorrhage was defined as bleeding confined to the ventricular system without parenchymal or subarachnoid hemorrhage involved. Results: Of the included eighteen patients, 55.6% were female, and the mean age was 13.8 ± 6.0 years. The most common symptoms on presentation were headache (77.8%) and vomiting (33.3%). Fifteen patients (83.3%) were diagnosed with known etiologies, including arteriovenous malformations (66.7%), Moyamoya disease (11.1%), and aneurysms (5.6%). Idiopathic PIVH was diagnosed in only 3 patients (16.7%). Fifteen patients (83.3%) underwent surgical intervention, and 3 patients (16.7%) received conservative treatment. Four patients (28.6%) had an unfavorable outcome at discharge and unfavorable was observed in 3 patients (16.7%) at the 3-month follow-up. Higher Graeb score was associated with an unfavorable outcome both in short-time and long-time follow-up. Conclusions: Most primary intraventricular hemorrhage patients were diagnosed with arteriovenous malformations in the pediatric population. Specific surgical treatment of underlying etiologies should be required to increase clinical improvement. The children with higher Graeb score at admission tended to have poor early and late outcome. Keywords: Primary intraventricular hemorrhage; pediatric; surgery; vascular disorders.


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