scholarly journals On the determination of soil pH

1965 ◽  
Vol 37 (1) ◽  
pp. 51-60
Author(s):  
Ritva Ryti
Keyword(s):  
Soil Ph ◽  
Salt Content ◽  
Soil Samples ◽  
Liquid Ratio ◽  
Ph Values ◽  
Water Suspensions ◽  
The Mean ◽  
The Difference ◽  
Soil Groups

In the present paper the routine determination of soil pH in the laboratory was studied using a material of 15 soil samples of various kind and in addition, two larger soil groups, consisting of 80 and 406 samples respectively. In comparing the pH values determined in water and in 0.01 M CaCl2 suspensions, the latter proved to be almost independent of the soil/liquid ratio between 1: 2.5 and 1: 10, that markedly affected the pHH2O values. The change with time from the pH values measured after the first hour showed less variation in CaCl2 suspensions than in water suspensions; the constancy observed in pHCaCl2 values indicating that a relatively short equilibration period of 1—2 hours would be sufficient. To sum up these results, the use of 0.01 M CaCl2 would mean easy and accurate measurements well suited to mass pH determinations. A linear relationship and a highly significant positive correlation was found between pHH2O and pHCaCl2 values in a material of 406 soil samples. The difference between the two values, which largely depends on the soils’ own salt content, ranged from 0 to 1.1 pH units, with the mean difference of 0.49. Therefore, the suggested use of a constant correction factor to bring the pHCaCl2 values to the level of the pH measured in water, is not recommendable. The main advantage of using 0.01 M CaCl2 would be the concealing of differences in salt content of a soil. The use of pHCaCl2 values would also offer new ways for getting more information about a soil’s exchange capacities, as it provides the center point for TERÄSVUORI’s (13) soil curve.

scholarly journals Comparative Analysis of Different Local Anesthetic Solutions Available in Market: An In Vitro and Clinical Study

2021 ◽  
Author(s):  
Eisha Imran ◽  
Faisal Moeen ◽  
Beenish Abbas ◽  
Bakhtawar Yaqoob ◽  
Mehreen Wajahat ◽  
...  
Keyword(s):  
Comparative Analysis ◽  
Local Anesthetic ◽  
Compositional Analysis ◽  
Bacterial Activity ◽  
Similar Composition ◽  
Ph Values ◽  
Significant Difference ◽  
The Mean ◽  
The Difference

Abstract Objectives The study aimed to evaluate and compare various commercially available local anesthetic solutions. Materials and Methods A total of 150 commercially available local anesthetic cartridges of similar composition (2% lidocaine with epinephrine 1:100,000) were randomly collected and divided into 3 groups. The designations of groups were selected from their product names such that each group consisted of 60 cartridges. Group S (Septodont, France) Group M (Medicaine, Korea) and Group H (HD-Caine, Pakistan). The samples were divided into five sub-groups, each consisting of 10 cartridges from each group to investigate each parameter. Results The acquired data was statistically analyzed and compared (using SPSS version 12). Compositional analysis revealed a non-significant (P>0.05) difference when the three Groups were compared with standard lidocaine and epinephrine solutions. The mean pH values of samples from group S, M and H respectively fell within the range of pH values of commercially available solutions. Non-significant difference in EPT values of Group S and H was found when efficacy was compared (p = 0.3), however a significant difference (p < 0.01) was observed in contrast to Group M. Anti-bacterial activity was observed in all the group and a non-significant difference in cell viability values of Group S and M was found (p = 0.6), while the difference was significant in comparison to Group H. Conclusion Within the limitations of these investigations, it appears that the properties of different manufacturers fall within the recommended ranges as mentioned in literature and do not appear to be statistically different in the variables we have tested.

Determination of aerobic work and power on a rope-braked cycle ergometer by direct measurement

2006 ◽  
Vol 31 (4) ◽  
pp. 392-397 ◽  
Author(s):  
Rae S. Gordon ◽  
Kathryn L. Franklin ◽  
Julien S. Baker ◽  
Bruce Davies
Keyword(s):  
Direct Measurement ◽  
Power Estimation ◽  
Cycle Ergometer ◽  
Mean Power ◽  
Physiological Assessment ◽  
Brake Force ◽  
The Mean ◽  
The Difference ◽  
Work Done

The purpose of this study was to compare the power and work outputs of a cycle ergometer using the manufacturer’s guidelines, with calculations using direct flywheel velocity and brake torque. A further aim was to compare the values obtained with those supplied by the manufacturer. A group of 10 male participants were asked to pedal a Monark 824E ergometer at a constant cadence of 60 r/min for a period of 3 min against a resistive mass of 3 kg. The flywheel velocity was measured using a tachometer. The brake force was determined by measuring the tension in the rope on either side of the flywheel. The calculated mean power was 147.45 ± 6.5 W compared with the Monark value of 183 ± 3.7 W. The difference between the methods for power estimation was 18% and was statistically significant (p < 0.01). The mean work done by the participants during the 3 min period was found to be 26 460 ± 1145 J compared with the Monark value of 33 067 ± 648 J (p < 0.01). The Monark formulae currently used to determine the power and work done by a participant overestimates the actual values required to overcome the resistance. There findings have far-reaching implications in the physiological assessment of athletic, sedentary, and diseased populations.

Differential pressure in shunt therapy: investigation of position-dependent intraperitoneal pressure in a porcine model

2013 ◽  
Vol 12 (6) ◽  
pp. 575-581 ◽  
Author(s):  
Florian Baptist Freimann ◽  
Jens Ötvös ◽  
Sascha Santosh Chopra ◽  
Peter Vajkoczy ◽  
Stefan Wolf ◽  
...  
Keyword(s):  
Body Position ◽  
Pressure Sensors ◽  
Differential Pressure ◽  
Intraperitoneal Pressure ◽  
Vertical Distance ◽  
Ventriculoperitoneal Shunting ◽  
Hydrostatic Force ◽  
The Mean ◽  
The Difference

Object The differential pressure between the intracranial and intraperitoneal cavities is essential for ventriculoperitoneal shunting. A determination of the pressure in both cavities is decisive for selecting the appropriate valve type and opening pressure. The intraperitoneal pressure (IPP)—in contrast to the intracranial pressure—still remains controversial with regard to its normal level and position dependency. Methods The authors used 6 female pigs for the experiments. Two transdermal telemetric pressure sensors (cranial and caudal) were implanted intraperitoneally with a craniocaudal distance of 30 cm. Direct IPP measurements were supplemented with noninvasive IPP measurements (intragastral and intravesical). The IPP was measured with the pigs in the supine (0°), 30°, 60°, and vertical (90°) body positions. After the pigs were euthanized, CT was used to determine the intraperitoneal probe position. Results With pigs in the supine position, the mean (± SD) IPP was 10.0 ± 3.5 cm H2O in a mean vertical distance of 4.5 ± 2.8 cm to the highest level of the peritoneum. The difference between the mean IPP of the cranially and the caudally implanted probes (Δ IPP) increased according to position, from 5.5 cm H2O in the 0° position to 11.5 cm H2O in the 30° position, 18.3 cm H2O in the 60° position, and 25.6 cm H2O in the vertical body position. The vertical distance between the probe tips (cranially implanted over caudally implanted) increased 3.4, 11.2, 19.3, and 22.3 cm for each of the 4 body positions, respectively. The mean difference between the Δ IPP and the vertical distance between both probe tips over all body positions was 1.7 cm H2O. Conclusions The IPP is subject to the position-dependent hydrostatic force. Normal IPP is able to reduce the differential pressure in patients with ventriculoperitoneal shunts.

scholarly journals Determination of LC and LB

1995 ◽  
Vol 10 ◽  
pp. 205-205
Author(s):  
T. Fukushima
Keyword(s):  
Time Scales ◽  
Full Paper ◽  
Numerical Integrations ◽  
Best Estimate ◽  
Analytical Formulas ◽  
The Mean ◽  
The Difference ◽  
Scale Difference ◽  
Astronomical Constants

The location-independent part of TCB-TCG, the difference between the two new time scales adopted by the IAU (1992), was integrated numerically for three JPL planetary/lunar ephemerides; DE102, DE200, and DE245. The differences among these three integrations were mostly explained by the difference in the adopted constants of the ephemerides. It was shown that the post-Newtonian correction and the perturbation by asteroids are negligible except for the mean rate, LC. The comparison of these numerical integrations with the analytical formulas of Hirayama et al. (1987) and Fairhead and Bretagnon (1990) as well as their extended versions lead to the best estimate of LC asCombining this with the recent value of the geoid potential in Bursa et al. (1992), we estimated the value of LB, the scale difference between TCB and TT, asTable I summarizes these conclusions. These estimates of LC and LB are more reliable than the former values we gave (Fukushima et al. 1986). The new estimate of LB will be useful in converting the numerical values of some precisely determined astronomical constants such as AU measured in meter from those in TDB to those in TCB. Also the numerically integrated TCB-TCG, which are to be called Time Ephemeris, will be useful when converting between TCB and TDB, i.e. the time scales themselves. The full paper will be appeared in A & A with the title of Time Ephemeris.

scholarly journals Cochran’s Q-Test on Soil Helminth Prevalence

2021 ◽  
Vol 58 (2) ◽  
pp. 169-185
Author(s):  
I. J. David ◽  
M. U. Adehi ◽  
P. O. Ikwuoche
Keyword(s):  
Soil Samples ◽  
The Other ◽  
Significance Level ◽  
Comparison Test ◽  
The Mean ◽  
The Difference ◽  
Comparison Technique

Summary A study was made of the prevalence of nine geohelminth egg types in 184 soil samples from 16 recreational parks in Abuja metropolis, Nigeria. Cochran’s Q-test was applied to determine whether the difference in the proportions of the egg types found in the soil samples was significant. At a 5% significance level, it was found that the prevalence of the egg types was significantly different in the 184 soil samples from 16 parks. To identify which of the geohelminth eggs had a significantly larger mean proportional prevalence, a minimum required difference mean comparison technique was applied. The mean comparison test showed that Taenia and Coccocidia eggs were highly prevalent, with significantly larger mean proportions than the other analyzed geohelminth eggs in the 184 examined soil samples.

scholarly journals Komposisi Jenis Gastropoda di Mangrove Desa Kaliwlingi dan Sawojajar, Jawa Tengah

2020 ◽  
Vol 9 (2) ◽  
pp. 167-174
Author(s):  
Erik Wijaya Kusuma ◽  
Ria Azizah Tri Nuraini ◽  
Retno Hartati
Keyword(s):  
Mangrove Forest ◽  
Diversity Index ◽  
Gastropod Species ◽  
Mangrove Area ◽  
Central Java ◽  
Mangrove Ecosystems ◽  
The Mean ◽  
The Difference ◽  
Different Characteristics

ABSTRAK : Desa Kaliwlingi dan Sawojajar mempunyai kawasan hutan mangrove dengan karakteristik berbeda. Kawasan hutan mangrove Kaliwlingi menjadi ekowisata mangrove sejak tahun 2016, sedangkan di Sawojajar merupakan kawasan mangrove alami. Perbedaan fungsi tersebut diduga dapat mempengaruhi keanekaragaman hayati yaitu salah satunya adalah gastropoda. Tujuan dari penelitian ini adalah untuk mengetahui struktur komunitas Gastropoda di ekosistem mangrove Desa Kaliwlingi dan Sawojajar, Kab.Brebes, Jawa Tengah. Pengambilan sampel dilakukan pada bulan Juni sampai Juli 2018. Penentuan titik sampling menggunakan metode purposive pada 3 stasiun dengan tiga kali pengulangan. Hasil penelitian menunjukan terdapat 2 subkelas yaitu Pulmonata dan Prosobranchiata, dengan 3 famili dan  9 spesies gastropoda dari 3 famili, yaitu Elliobidae; Cassidula aurisfelis (Elliobidae), C. nucleus (Elliobidae), Littoraria articulate (Littorinidae), L. carinifera (Littorinidae), L. melanostoma (Littorinidae), L. scabra (Littorinidae), Telescopium telescopium (Potamididae), Terebralia obtuse (Potamididae), T. palustris (Potaminidae).  Nilai kelimpahan rata-rata gastropoda Desa Kaliwlingi dan Desa Sawojajar masing-masing 20,28 dan 16,36 Ind/m². Indeks Keanekaragaman (H’) gastropoda di kawasan mangrove Desa Kaliwlingi dan Desa Sawojajar termasuk ke dalam kategori rendah ke tinggi, sedangkan indeks keseragamannya  berkategori rendah.  Tidak ada jenis gastropod yang mendominasi di kawasan mangrove Kaliwlingi dan Sawojajar, dengan pola sebaran gastropoda mengelompok.ABSTRACT: Kaliwlingi and Sawojajar villages have mangrove forest areas with different characteristics. The Kaliwlingi mangrove forest area has been established as mangrove ecotourism since 2016, while in Sawojajar it is a natural mangrove area. The difference in function is thought to affect biodiversity, one of which is gastropods. The purpose of this study was to determine the structure of the Gastropoda community in the mangrove ecosystems of Kaliwlingi and Sawojajar Villages, Kab. Brebes, Central Java. Sampling was conducted in June to July 2018. Determination of the sampling points using purposive methods at 3 stations with three repetitions. The results showed that there were 2 subclasses, namely Pulmonata and Prosobranchiata, with 3 families and 9 gastropod species from 3 families, namely Elliobidae; Cassidula aurisfelis (Elliobidae), C. nucleus (Elliobidae), Littoraria articulate (Littorinidae), L. carinifera (Littorinidae), L. melanostoma (Littorinidae), L. scabra (Littorinidae), Telescopium telescopium (Potamebidide) ), T. palustris (Potaminidae). The mean abundance of gastropods in Kaliwlingi Village and Sawojajar Village were 20.28 and 16.36 Ind / m² respectively. Diversity Index (H ') of gastropods in the mangrove areas of Kaliwlingi Village and Sawojajar Village are in the low to high category, while the uniformity index is categorized as low. There is no type of gastropod that dominates in the Kaliwlingi and Sawojajar mangrove areas, and gastropod distributed as a grouped.  

THE MAINTENANCE OF A STANDARD OF ELECTROMOTIVE FORCE: NOTES ON STANDARD WESTON CELLS

1930 ◽  
Vol 3 (5) ◽  
pp. 473-489
Author(s):  
A. Norman Shaw ◽  
H. E. Reilley
Keyword(s):  
Electromotive Force ◽  
Essential Feature ◽  
Mean Deviation ◽  
Entire Group ◽  
Standard Cells ◽  
Characteristics Analysis ◽  
A Cell ◽  
The Mean ◽  
The Difference

A detailed procedure for the maintenance of a standard of voltage to within one or two parts in a million is described.In so far as these investigations have proceeded, neutral saturated cells have been found to be superior to acid cells as independent standards for a period of many years, though the latter are preferable for purposes of ordinary precision or shorter periods. The recommended code of procedure is briefly as follows: a number of cells should be constructed according to standard specifications with the new requirements of uniformity of container and speed of preparation, and observations made upon them every few days for a period of three months. The differences in electromotive force (at constant temperature) should be determined between each cell in the group and any one of them chosen arbitrarily as reference cell, and certain new selection and rejection rules applied. In accordance with these rules a cell should be rejected: (a) if its deviation from the mean electromotive force of the group has increased or decreased by 10 microvolts or more during the preceding two weeks; or (b) if it differs in electromotive force from the mean of the group by more than 10 +d microvolts where d is the mean deviation of the cells of the group. If d exceeds 20 microvolts the entire group should be considered untrustworthy. The selected cells should be observed for three additional months, the rejection rules again applied and if a specified proportion survive elimination, the initial reference mean of the laboratory may be established.At intervals of several months additional groups of cells, neutral and acid, should be constructed and exchanges made with laboratories possessing cells of known characteristics. Analysis of the resulting observations determines: (a) the constants in the aging* equation for the reference batch, and (b) the difference between the initial reference mean of the laboratory and the estimated value of the international reference mean.Examples of the analysis of cell observations are given, illustrating the establishment of the initial reference mean, the recapture of this value when the aging coefficients are known, and the preliminary determination of the aging equation for a given group of cells. The use of the aging equation is found to be the essential feature in the attainment of increased precision.A summary of data on standard cells is included.

scholarly journals Evaluation of the pH and titratable acidity of teas commercially available in Brazilian market

2014 ◽  
Vol 62 (1) ◽  
pp. 59-64 ◽  
Author(s):  
Letícia Bello Flores LUNKES ◽  
Lina Naomi HASHIZUME
Keyword(s):  
Titratable Acidity ◽  
T Test ◽  
Ilex Paraguariensis ◽  
Yerba Mate ◽  
Mean Values ◽  
Ph Values ◽  
The Mean ◽  
The Difference

OBJECTIVE: Tea has been considered a healthy alternative to other industrialized beverages. The objective of this study was to assess the erosive potential of teas commercially available in Brazil by pH and titratable acidity measures. METHODS: Eighteen teas available in Brazilian market were selected for this study (read to drink and brewed tea), and a brand of yerba mate (Ilex paraguariensis). Each product was analyzed for pH and titratable acidity. For comparison between different kinds of teas, the Student t test was used. RESULTS: The mean pH values for ready to drink teas ranged between 2.89 and 4.03, while for the brewed teas and yerba mate the values ranged between 6.75 and 7.89. The difference between the two groups was significant (p < 0.05). Regarding titratable acidity, the ready to drink teas showed mean values ranging between 3.77 ml and 12.68 ml. Brewed teas (including yerba mate) were not tested for titratable acidity because their pH values were greater than 7.0. CONCLUSION: Among the teas commercially available, ready to drink teas have lower pH values and higher titratable acidity compared to other teas. It suggests that they have an erosive potential.

scholarly journals Determination of Inulin in Foods

2000 ◽  
Vol 83 (3) ◽  
pp. 675-678 ◽  
Author(s):  
Breda Simonovska
Keyword(s):  
Standard Deviation ◽  
Oxalic Acid ◽  
Thin Layer ◽  
Degree Of Polymerization ◽  
Test Solution ◽  
Boiling Water Bath ◽  
Before And After ◽  
The Mean ◽  
The Difference

Abstract A method was developed for determining fructan inulin in various foods (yogurts, honey cakes, chocolates). Warm water was applied for extraction of samples, and mono- and dissacharides were determined by a thin-layer chromatographic densitometric method. A portion of the test solution was hydrolyzed 30 min with 1% oxalic acid in a boiling water bath. Fructose was determined in the hydrolysate. The amount of inulin in a sample was calculated as the difference between the amount of fructose in the sample before and after hydrolysis. The fructose from sucrose formed during the hydrolysis was also considered. The mean recovery from yogurt fortified with 4% inulin was 95.5 ± 4.5% (mean ± standard deviation); from honey cakes extract fortified with 10% inulin, 97.3 ± 5.5%; and from chocolate extract fortified with 30% inulin, 98.6 ± 6.6% (6 replicates in all cases). Determination of glucose is not necessary for analyzing fructans with the composition expressed shortened to GFn−1 (G, glucose; F, fructosyl) with the average degree of polymerization 8 ≤ n ≤ 15.

scholarly journals Establishment of a new relationship between posed smile width and lower facial height: A cross-sectional study

2015 ◽  
Vol 09 (03) ◽  
pp. 394-399 ◽  
Author(s):  
Aby Abraham ◽  
Jinu George ◽  
Elbe Peter ◽  
Koshi Philip ◽  
Rajesh Chankramath ◽  
...  
Keyword(s):  
Soft Tissue ◽  
Cross Sectional Study ◽  
Cross Sectional ◽  
Facial Height ◽  
The Face ◽  
Facial Proportions ◽  
Males And Females ◽  
The Mean ◽  
The Difference

ABSTRACT Objective: The present study is intended to add a new parameter that would be useful in orthodontic clinical evaluation, treatment planning, and determination of vertical dimension (at occlusion). Materials and Methods: Standardized videographic recording of 79 subjects during posed smile was captured. Each video was then cut into 30 photos using the free studio software. The widest commissure-to-commissure posed smile frame (posed smile width [SW]) was selected as one of 10 or more frames showing an identical smile. Lower third of the face is measured from subnasale to soft tissue menton using a digital vernier caliper. Two values were then compared. Ratio between lower facial height and posed SW was calculated. Results: The co-relation between smiling width and lower facial height was found to be statistically significant (P < 0.01). The ratio of lower facial height and smiling width was calculated as 1.0016 with a standard deviation (SD) = 0.04 in males and 1.0301 with an SD = 0.07 in females. The difference between the mean lower facial height in males and females was statistically significant with a t = 10.231 and P = 0.000. The difference between the mean smiling width in males and females was also statistically significant with a t = 5.653 and P = 0.000. Conclusion: In class I subjects with pleasing appearance, normal facial proportions, normal overjet and overbite, and average Frankfort mandibular angle, the lower facial height (subnasale to soft tissue menton) is equal to posed SW.

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