scholarly journals The absorption in lead of the γ-rays emitted by radium and radium C

1915 ◽  
Vol 91 (630) ◽  
pp. 396-404 ◽  
Keyword(s):  
Atomic Weight ◽  
Great Accuracy ◽  
Complete Analysis ◽  
Characteristic Radiation ◽  
Anomalous Effect ◽  
Γ Radiation ◽  
Additional Information ◽  
Absorbing Material ◽  
Γ Rays ◽  
The Difference

In a previous paper by Rutherford and the author attention has been drawn to the fact that the two types of γ-radiation emitted by radium B and radium c which are exponentially absorbed by aluminium both show irregular absorption curves when lead is used as the absorbing material. The curve obtained for pure radium C was observed to fall far more rapidly than was to be expected only after traversing a thickness of 1·5cm of lead. The absorption curve in lead of the γ-rays from radium B was obtained by taking the difference between the radium (B+C) and the radium C curves. The results so obtained were not determined with very great accuracy, but they served to show that in this case, to, the absorption is not exponential , and that the absorption coefficient rapidly diminished from about μ =11(cm. -1 ) to μ =2(cm -1 ). The accuracy of the curves did not, however, permit of their complete analysis as in the case of those previously obtained for aluminium. During the course of his work on characteristic radiations Barkla has Pointed out and investigated the anomalous effect on the absorption of a characteristic radiation by an element whose atomic weight is near to that of the element which emits the radiation. His experiments were, however, confined to elements of comparatively low atomic weight. As the atomic weights of radium B and radium C can only differ by a small amount, and as they have atomic numbers differing only by unity, viz., radium B=82 and radium C=83, it seemed of importance to determine accurately the absorption curves in lead, and to examine whether any additional information can be obtained which may indicate whether the radiations emitted by radium B and radium C are characteristic of these elements and fall into the series given by Barkla.

scholarly journals Energy relations in the β-ray type of radioactive disintegration

1933 ◽  
Vol 141 (845) ◽  
pp. 502-511 ◽  
Keyword(s):  
Energy Difference ◽  
Atomic Weight ◽  
Maximum Energy ◽  
Excess Energy ◽  
Binding Energies ◽  
Upper Limit ◽  
Γ Rays ◽  
The Difference ◽  
Band Spectra ◽  
Energy Relations

The difficulties connected with the continuous β-disintegration are well known. The fact that a given isotope of any element has a definite atomic weight suggests that the energy of the normal state of any nucleus is quantized ; further evidence is afforded by the alternating intensities in band spectra. Evidence from the fine structure of α -rays and from the γ-rays, proves that nuclei are capable of existing in quantized excited states. In fact, in all transformations where α -particles, γ-radiation or protons are ejected from nuclei, the evidence suggests, (i) that the nuclear energy is quantized, and (ii) that energy is conserved. On the other hand, when a nucleus P transforms itself into a nucleus Q by emission of a β-particle, the β-particle has all energies between zero and a definite upper limit. One may either conclude that the energy either of P or of Q is not quantized, or that energy is not conserved in the transition. Since the a-transitions leading up to P , and starting from Q , show no sign of any indefiniteness in the energy, it is difficult to accept the former alternative ; and it is thus usual to suppose that energy is not conserved. In this paper we make the suggestion that the sharp upper limit of the β-rav spectrum is a significant parameter with which to classify a β-disintegration. We suggest the following hypotheses : two elements P , Q , such that P -> Q is a β-disintegration, both possess definite atomic weights, and hence definite binding energies. Following Heisenberg* we assume that β-disintegration can only take place if the energy E P of the nucleus P is higher than the energy E q of the nucleus Q. We make the new assumption that the energy difference E P — E q is equal to the upper limit of the i. e., to the maximum energy with which a β-particle can be expelled. According to our assumption, the β-particle may be expelled with less energy than the difference of the energies E P — E q , of the two nuclei, but not with more energy . We do not wish in this paper to dwell on what happens to the excess energy in those disintegrations in which the electron is emitted with less than the maximum energy. We may, however, point out that if the energy merely disappears, implying a breakdown of the principle of energy conservation, then in a β-ray decay energy is not even statistically conserved. Our hypothesis is, of course, also consistent with the suggestion of Pauli that the excess energy is carried off by particles of great penetrating power such as neutrons of electronic mass.

Radioactive Pollution

2002 ◽  
Keyword(s):  
Atomic Number ◽  
Electromagnetic Waves ◽  
Neutron Radiation ◽  
Atomic Weight ◽  
Atomic Mass Unit ◽  
X Rays ◽  
Orbital Electron ◽  
Γ Rays ◽  
The Difference ◽  
A Charge

Radiation that, on passage through matter, produces ions by knocking electrons out of their orbits is called ionizing radiation. This radiation is produced through decomposition of unstable, naturally occurring or synthetic elements referred to as radionuclides. The four types of radiation are ∝-particles, β-particles, γ-rays, and neutrons. The ∝-particles have a mass of two protons and two neutrons and a charge of +2; β -particles are electrons with a mass of 0.00055 atomic mass unit (amu) and a charge of –1; γ -rays and X-rays are high-frequency electromagnetic waves with no mass and no charge. The difference between γ -rays and X-rays is that γ -rays occur naturally, whereas X-rays are generated. In addition, γ -rays are of higher frequency than X-rays. Release of an ∝ -particle leads to the formation of a daughter element with an atomic number 2 units lower and an atomic weight 4 units lower than that of the parent nuclide. Similarly, release of a β -particle from the nucleus causes conversion of a neutron to a proton, producing a daughter element with the same atomic weight as the parent nuclide but with its atomic number increased by 1 unit. Neutron radiation does not occur naturally and is released only from synthetic radionuclides. Neutrons, which have no charge, are formed from protons. This conversion is accompanied by the release of an orbital electron from the atom. Neutrons produce ions indirectly, by collisions with hydrogen atoms. The impact knocks out protons, which in turn produce ions on passage through matter. Capture of a neutron forms an isotope of the parent nuclide with its atomic weight increased by 1 unit. The mode of action of particles (∝ and β ) varies from that of photons (γ - and X-rays). When ∝- or β -particles travel through matter, their electric charges (positive or negative) cause ionization of the atoms in the matter. This is called a direct effect. Whereas the track of ∝- particles is short and straight, β -particles scatter, frequently producing a wavy track. Gamma- and X-rays act indirectly.

scholarly journals The excitation of γ -rays by β -rays

1914 ◽  
Vol 90 (621) ◽  
pp. 521-531 ◽  
Keyword(s):  
Atomic Weight ◽  
Balance Method ◽  
The Other ◽  
Characteristic Radiation ◽  
Definite Evidence ◽  
Radioactive Substances ◽  
Γ Rays ◽  
The Impact ◽  
First Time ◽  
Soft Radiation

The excitation of γ -rays by the impact of β -rays on different substances has been investigated by several observers. The question was first systematically examined by J. A. Gray. He showed that penetrating γ -rays are produced by the β -rays of radium E when they impinge on different materials, the amount of γ -radiation increasing with increase of atomic weight of the material. The particular disposition used in his first experiments was not suitable for the examination of any soft types of radiation which might have been excited, but in later work he showed, for the first time, that characteristic radiations were excited in the case of silver, tin, barium and cerium. Chadwick, using the balance method of Rutherford and Chadwick, examined whether the β -rays from radium B and radium C excite penetrating γ -rays in different kinds of matter. Definite evidence was obtained that an excited radiation amounting to about 0.5 per cent, of the primary γ -radiation is produced. This method, however, was not suitable for the detection of soft characteristic radiations. These general results have recently been confirmed by Starke, using the β -rays from a strong preparation of mesothorium. In previous papers by Rutherford and the author on the analysis of the γ -rays from radioactive substances, it has been shown that the γ -rays emitted by the different products can be separated into groups differing widely in penetrating power. Some of these radiations appear to be characteristic of the elements by which they are emitted and fall into one or other of the series given by Barkla. On the other hand, some of the groups of rays found do not appear to belong to either series. It was further shown in previous work that when radium C is deposited on nickel a soft radiation is given out which is entirely absorbed by 2 mm. of aluminium. This soft radiation was much more readily absorbed than that emitted by radium B, and for which μ = 40 (cm. -1 ), but it was appreciably harder than the characteristic radiation of nickel. Moreover, when radium C was deposited on silver, little, if any, soft radiation appeared to be emitted. It seemed of importance, therefore, to examine in detail the nature of the radiation excited by the β - and γ -rays from radium B and radium C, and to examine the bearing of the results on the type of radiation emitted by different materials on which radium C is deposited.

scholarly journals Urinary Microbiome Characteristics in Female Patients with Acute Uncomplicated Cystitis and Recurrent Cystitis

2021 ◽  
Vol 10 (5) ◽  
pp. 1097
Author(s):  
Jeong-Ju Yoo ◽  
Hee Shin ◽  
Ju Song ◽  
Minjung Kim ◽  
Jina Yun ◽  
...  
Keyword(s):  
Urine Culture ◽  
Culture Methods ◽  
Microbiome Composition ◽  
Additional Information ◽  
Transurethral Catheter ◽  
Urinary Microbiome ◽  
Acute Uncomplicated Cystitis ◽  
The Difference ◽  
Uncomplicated Cystitis ◽  
Recurrent Cystitis

Traditionally, the diagnostic mainstay of recurrent urinary tract infection has been urinary culture. However, the causative uropathogen of recurrent cystitis has not been well established. Urine DNA next-generation sequencing (NGS) can provide additional information on these infections. Herein, we compared urine NGS results and urine cultures in patients with acute uncomplicated cystitis (AUC) and recurrent cystitis (RC), and evaluated the difference in microbiome patterns in the NGS results. Patients who underwent urine culture and NGS due to AUC or RC were retrospectively reviewed. All urine samples were collected via a transurethral catheter and studied utilizing a type of NGS called 16S ribosomal RNA gene amplification and sequencing. The sensitivity of urine NGS was significantly higher than that of conventional urine culture (69.0% vs. 16.7%, p < 0.05). The detection rate of urine NGS was slightly lower in the RC group than in the AUC group (67.7% vs. 72.7%). Microbiome diversity was significantly higher in the RC group compared to the AUC group (p = 0.007), and the microbiome composition was significantly different between the AUC and RC groups. In the urine NGS results, Pseudomonas, Acinetobacter, and Enterobacteriaceae were found in the AUC group, and Sphingomonas, Staphylococcus, Streptococcus, and Rothia spp. were detected in the RC group. Urine NGS can significantly increase the diagnostic sensitivity compared to traditional urine culture methods, especially in RC patients. AUC and RC patients had significant differences in bacterial diversity and patterns. Therefore, recurrent cystitis might be approached from a different perspective.

scholarly journals Researches on the tides. Seventh series. On the diurnal inequality of the height of the tide, especially at Plymouth and at Sincapore : and on the mean level of the sea

1837 ◽  
Vol 3 ◽  
pp. 465-466
Keyword(s):  
Great Accuracy ◽  
Equilibrium Theory ◽  
The Other ◽  
Correct Knowledge ◽  
The Mean ◽  
The Difference ◽  
Naval Officers ◽  
Similar Kind

The diurnal inequality which the author investigates in the present paper, is that by which the height of the morning tide differs from that of the evening of the same day; a difference which is often very considerable, and of great importance in practical navigation, naval officers having frequently found that the preservation or destruction of a ship depended on a correct knowledge of the amount of this variation. In the first section of the paper he treats of the diurnal inequality in the height of the tides at Plymouth, at which port good tide observations are regularly made at the Dock Yard ; and these observations clearly indicate the existence of this inequality. As all the other inequalities of the tides have been found to follow the laws of the equilibrium theory, the author has endeavoured to trace the laws of the diurnal inequality by assuming a similar kind of correspondence with the same theory; and the results have confirmed, in the most striking manner, the correctness of that assumption. By taking the moon’s declination four days anterior to the day of observation, the results of computation accorded, with great accuracy, with the observed heights of the tides: that is, the period employed was the fifth lunar transit preceding each tide. In the second section, the observations made on the tides at Sincapore from August 1834 to August 1835, are discussed. A diurnal inequality was found to exist at that place, nearly agreeing in law and in amount with that at Plymouth ; the only difference being that, instead of four days, it was found necessary to take the lunar declination a day and a half preceding the tide ; or, more exactly, at the interpolated,or north lunar transit, which intervened between the second and third south transit preceding the tide. The diurnal inequality at Sincapore is of enormous magnitude, amounting in many cases to six feet of difference between the morning and evening tides; the whole rise of the mean tide being only seven feet at spring tides, and the difference between mean spring and neap tides not exceeding two feet.

Detection of polar stratospheric clouds with ERS-2/GOME data

1995 ◽  
Vol 13 (4) ◽  
pp. 395-405
Author(s):  
R. Meerkoetter
Keyword(s):  
Radiative Transfer ◽  
European Research ◽  
Polar Stratospheric Clouds ◽  
Additional Information ◽  
Tropospheric Aerosol ◽  
Ozone Monitoring ◽  
The Difference ◽  
Stratospheric Clouds

Abstract. Based on radiative transfer calculations, it is studied whether polar stratospheric clouds (PSCs) can be detected by the new Global Ozone Monitoring Experiment (GOME) on board the second European Research Satellite (ERS-2) planned to be launched in 1995. It is proposed to identify PSC-covered areas by use of an indicator, the Normalized Radiance Difference (NRD), which relates the difference of two spectral radiances at 0.515 µm and 0.67 µm to one radiance measured in the centre of the oxygen A-band at 0.76 µm. Simulations are carried out for two solar zenith angles, θ=78.5° and θ=86.2°. They indicate that, in presence of PSCs and with increasing solar zenith angles above θ=80°, the NRD decrease to values clearly below those derived under conditions of a cloud-free stratosphere. Results for θ=86.2° show that the method is successful independent of existing tropospheric clouds, of different tropospheric aerosol loadings, and of surface albedos. Results for θ=78.5° illustrate that PSC detection under conditions of smaller solar zenith angles θ80° needs additional information about tropospheric clouds.

Somatosensory and Auditory Brain Stem Conduction after Head Injury: A Comparison with Clinical Features in Prediction of Outcome

Neurosurgery ◽  
1990 ◽  
Vol 26 (2) ◽  
pp. 278-285 ◽  
Author(s):  
Kenneth Lindsay ◽  
Aydin Pasaoglu ◽  
David Hirst ◽  
Gwen Allardyce ◽  
Ian Kennedy ◽  
...  
Keyword(s):  
Head Injury ◽  
Brain Stem ◽  
Evoked Potential ◽  
Predictive Accuracy ◽  
Normal Subjects ◽  
Prediction Of Outcome ◽  
Prognostic Information ◽  
Additional Information ◽  
Auditory Brain Stem ◽  
The Difference

Abstract Evoked potential conduction times in brain stem auditory (BCT) and central somatosensory pathways (CCT) were recorded from 23 normal subjects and 101 patients with severe head injury. Abnormalities in the CCT and the BCT findings correlated with the clinical indices of brain damage (coma score, motor response, pupil response, and spontaneous and reflex eye movements) in the head-injured patients and each correlated with outcome at 6 months from the injury. The CCT in the “best” hemisphere produced the strongest correlation with outcome (P&lt;0.001). The correlation of the CCT with outcome was stronger in the 47 patients examined 2 to 3 days after the injury (P&lt;0.001) compared to the 34 patients examined within 24 hours after the injury (P&lt;0.02). No such difference was noted for the BCT. Serial studies within the first 2 weeks of injury did not show a consistent pattern and repetition of the investigation over this period did not provide any additional information. We used an INDEP-SELECT discriminant analysis program to determine whether information from the evoked potential data could improve prediction of outcome based on clinical data alone. With the addition of the CCT, the predictive accuracy (expressed as the correct classification probability) increased only slightly from 77 to 80%, and the difference was not significant. We conclude that central somatosensory and auditory brain stem conduction times provide useful prognostic information in paralyzed or sedated patients, but when neurological examination is feasible the benefits of evoked potential analysis do not justify the effort involved in data collection.

Neural network processing of radar scanning data array

2021 ◽  
Author(s):  
V.E. Dmitriyev ◽  
D.V. Popov ◽  
V.A. Shakhnov
Keyword(s):  
Spatial Perception ◽  
Digital Processing ◽  
Radar Data ◽  
Information Value ◽  
Data Array ◽  
Additional Information ◽  
Distribution Of Values ◽  
The Difference ◽  
Radar Data Processing ◽  
Made In

This article deals with the digital processing of a matrix radar image. The information received from the radar scanner needs to be transformed to enable visual perception. The article describes the main methods of digital processing of matrix data, presents the images transformed by them. The aim of the article was the development of a radar data processing algorithm that identifies the contours and edges of examined objects. The authors propose an algorithm for isolating the geometric structure of the scanned area. The difference between the processing method and the known analogues is based on the nature of the change in the values of the array being processed and consists in the double operation of extracting the gradient of the distribution of values. The software implementation of the algorithm is made in C++ using methods from an open library of computer vision. The efficiency of the algorithm was estimated based on comparison with the algorithms for determining edges based on linear filtering and neural networks. The results of the work can be used to create software for mobile short-range radar devices. Imaging from object boundaries and their edges provides spatial perception of the image by the operator, and free areas are available for rendering additional information. This solution allows you to combine scanning devices and thereby increase the information value of the result.

Linguistic cues facilitate children’s understanding of belief-reporting sentences

2021 ◽  
pp. 014272372110486
Author(s):  
Xiaowen Zhang ◽  
Peng Zhou
Keyword(s):  
Gold Medal ◽  
Judgment Task ◽  
False Belief ◽  
Value Judgment ◽  
Additional Information ◽  
Linguistic Cues ◽  
Truth Value ◽  
The Difference ◽  
Underlying Mechanisms ◽  
Mental Verbs

It has been well-documented that although children around 4 years start to attribute false beliefs to others in classic false-belief tasks, they are still less able to evaluate the truth-value of propositional belief-reporting sentences, especially when belief conflicts with reality. This article investigates whether linguistic cues, verb factivity in particular, can facilitate children’s understanding of belief-reporting sentences. Two experiments were implemented, one testing children’s knowledge of verb factivity using a gold medal task, and one investigating children’s interpretation of belief-reporting sentences using a truth-value-judgment task. Both experiments took advantage of the contrast between neutral non-factive mental verbs and strong negatively biased mental verbs. What sets the two apart is that the complement clause following a strong negatively biased mental verb is definitely false, whereas the one following a neutral non-factive mental verb remains indeterminate in the absence of additional information. The findings were that, first, 4-year-old children were able to tell the difference between the two types of mental verbs in factivity, and second, children’s performance was significantly improved when a strong negatively biased mental verb than when a neutral non-factive mental verb was used as the main verb of the belief-reporting sentences. The findings suggest that the use of strong negatively biased mental verbs facilitates children’s understanding of belief-reporting sentences. Implications of the findings are discussed in relation to the underlying mechanisms connecting verb factivity and false-belief understanding.

scholarly journals Value-at-risk modeling and forecasting with range-based volatility models: empirical evidence

2017 ◽  
Vol 28 (75) ◽  
pp. 361-376 ◽  
Author(s):  
Leandro dos Santos Maciel ◽  
Rosangela Ballini
Keyword(s):  
At Risk ◽  
Value At Risk ◽  
Garch Models ◽  
Time Interval ◽  
Risk Modeling ◽  
Additional Information ◽  
Volatility Models ◽  
Modeling And Forecasting ◽  
The Difference ◽  
Market Indexes

ABSTRACT This article considers range-based volatility modeling for identifying and forecasting conditional volatility models based on returns. It suggests the inclusion of range measuring, defined as the difference between the maximum and minimum price of an asset within a time interval, as an exogenous variable in generalized autoregressive conditional heteroscedasticity (GARCH) models. The motivation is evaluating whether range provides additional information to the volatility process (intraday variability) and improves forecasting, when compared to GARCH-type approaches and the conditional autoregressive range (CARR) model. The empirical analysis uses data from the main stock market indexes for the U.S. and Brazilian economies, i.e. S&P 500 and IBOVESPA, respectively, within the period from January 2004 to December 2014. Performance is compared in terms of accuracy, by means of value-at-risk (VaR) modeling and forecasting. The out-of-sample results indicate that range-based volatility models provide more accurate VaR forecasts than GARCH models.

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