The effect of cold shock and deep-freezing on ram spermatozoa collected by electrical ejaculation and by an artificial vagina

1968 ◽  
Vol 19 (1) ◽  
pp. 119 ◽  
Author(s):  
PJ Quinn ◽  
S Salamon ◽  
IG White
Keyword(s):  
Seminal Plasma ◽  
Congo Red ◽  
Cold Shock ◽  
Rapid Freezing ◽  
Staining Reaction ◽  
Deep Freezing ◽  
Freezing Method ◽  
Low Levels ◽  
Artificial Vagina ◽  
Better Than

Spermatozoa collected with an artificial vagina (AV) were more resistant to cold shock as judged by motility and staining reaction than when ejaculated electrically (EE). Dilution of AV spermatozoa in AV seminal plasma caused some increase in susceptibility to cold shock, particularly as judged by motility scores, but the evidence suggests that EE seminal plasma renders spermatozoa more susceptible than does AV seminal plasma. Spermatozoa exposed to cold shock immediately after collection were most permeable to Congo red and became increasingly impermeable when incubated at 30°C; the increase in resistance of AV spermatozoa was greater than that of EE spermatozoa. When 10 successive ejaculates were collected from rams by the artificial vagina there was no great change in volume but the spermatozoal concentration declined. After cold shock, the percentage of unstained spermatozoa fell to very low levels by the fifth ejaculate and there was also a decline in motility. The viability of semen thawed after freezing to –79°C by rapid freezing method was better than when a slow freezing method was used, particularly when the semen was collected with an artificial vagina.

EFFECTS OF LANGUAGE AND PRIOR KNOWLEDGE LEVELS ON HYPERTEXT READING COMPREHENSION

2020 ◽  
Author(s):  
Kshema Jose
Keyword(s):  
Reading Comprehension ◽  
Prior Knowledge ◽  
Language Proficiency ◽  
Language Competence ◽  
Additional Information ◽  
Reading Order ◽  
Low Levels ◽  
Online Texts ◽  
Characteristic Features ◽  
Better Than

<p>This study observed how two hypertext features – absence of a linear or author-specified order and availability of multiple reading aids – influence reading comprehension processes of ESL readers. Studies with native or highly proficient users of English, have suggested that readers reading hypertexts comprehend better than readers reading print texts. This was attributed to (i) presence of hyperlinks that provide access to additional information that can potentially help overcome comprehension obstacles and (ii) the absence of an author-imposed reading order that helps readers exercise cognitive flexibility. An aspect that remains largely un-researched is how well readers with low language competence comprehend hypertexts. This research sought to initiate research in the area by exploring the question: Do all ESL readers comprehend a hypertext better than a print text?</p> <p>Keeping in mind the fact that a majority of readers reading online texts in English can be hindered by three types of comprehension deficits – low levels of language proficiency, non-availability of prior knowledge, or both – this study investigated how two characteristic features of hypertext, viz., linking to additional information and non-linearity in presentation of information, affect reading comprehension of ESL readers. </p> <p>Two types of texts that occur in the electronic medium – linear or pre-structured texts and non-linear or self-navigating texts, were used in this study. Based on a comparison of subjects’ comprehension outcomes and free recalls, text factors and reader factors that can influence hypertext reading comprehension of ESL readers are identified. </p> Contradictory to what many researchers believe, results indicate that self-navigating hypertexts might not promote deep comprehension in all ESL readers.

Evaluation of Gas-Liquid Chromatography in Assays for Blood Volatiles

1965 ◽  
Vol 11 (11) ◽  
pp. 1023-1035 ◽  
Author(s):  
Alan Mather ◽  
Angel Assimos
Keyword(s):  
Liquid Chromatography ◽  
Alcohol Concentration ◽  
Quantitative Assay ◽  
Gas Liquid Chromatography ◽  
Internal Reference ◽  
Detection And Identification ◽  
Large Populations ◽  
The Common ◽  
Low Levels ◽  
Better Than

Abstract A simple screening by gas-liquid chromatography (GLC) can provide definitive answers in the detection and identification of a number of volatile substances, including acetone and the common alcohols. After identification, quantitative assay by an internal-reference technic yields highly specific values for ethyl alcohol concentration with a precision at least equal to (and for low levels, better than) that of conventional assays. The unique advantage of GLC is in its simultaneous quantitative assay of mixtures, some of which cannot be satisfactorily assayed or even recognized in any other way. The combination of speed and negligible sample volumes render the technic valuable for sequential studies on capillary blood samples and, potentially, for mass screening of large populations.

scholarly journals Seminal Plasma Proteins Revert the Cold-Shock Damage on Ram Sperm Membrane1

2000 ◽  
Vol 63 (5) ◽  
pp. 1531-1537 ◽  
Author(s):  
Beatriz Barrios ◽  
Rosaura Pérez-Pé ◽  
Margarita Gallego ◽  
Agustín Tato ◽  
Jesús Osada ◽  
...  
Keyword(s):  
Seminal Plasma ◽  
Plasma Proteins ◽  
Cold Shock ◽  
Seminal Plasma Proteins ◽  
Ram Sperm

The use of hollow sphere pigments as strength additives in paper and paperboard coatings—Part 1: The predictive nature of packing models on coating properties

TAPPI Journal ◽  
2020 ◽  
Vol 19 (11) ◽  
pp. 585-593
Author(s):  
ETHAN GLOR ◽  
BRIAN EINSLA ◽  
JOHN ROPER ◽  
JIAN YANG ◽  
VALERIY GINZBURG
Keyword(s):  
Particle Size ◽  
Hollow Sphere ◽  
Particle Packing ◽  
Particle Sizes ◽  
Coating Properties ◽  
Ideal System ◽  
Thermal Paper ◽  
Effect Of Particle Size ◽  
Low Levels ◽  
Better Than

Hollow sphere pigments (HSPs) are widely used at low levels in coated paper to increase coating bulk and to provide gloss to the final sheet. However, HSPs also provide an ideal system through which one can examine the effect of pigment size and particle packing within a coating due to their unimodal and tunable particle sizes. The work presented in Part 1 and Part 2 of this study will discuss the use of blends of traditional inorganic pigments and HSPs in coating formulations across a variety of applications for improved coating strength. Part 1 of this study focuses on the theory of bimodal spherical packing and demonstrates the predictive nature of packing models on the properties of coating systems containing HSPs of two different sizes. This study also examines conditions where the model fails by examining the effect of particle size on coating strength in sytems like thermal paper basecoats where the non-HSP component has a broad particle size distribution, and how these surprising trends can be used to generate better-than-expected thermal printing performance in systems with low HSP/clay ratios. Part 2 of this study focuses on the incorporation of HSPs of different particle sizes into paperboard formulations to affect coating strength and opacity.

La competencia motriz en estudiantes chilenos de 3° y 4° de educación básica. Aprendizajes esperados versus realidad (Motor competence in Chilean students in 3rd and 4th grade of primary school. Expected learning versus reality)

Retos ◽  
2021 ◽  
Vol 44 ◽  
pp. 515-524
Author(s):  
Daniel Rodríguez-Briceño ◽  
Felipe Castro-Vilugron ◽  
Mauricio Díaz-Alvarado ◽  
Jaime Carcamo Oyarzun
Keyword(s):  
Motor Performance ◽  
Fourth Grade ◽  
Learning Objectives ◽  
Motor Competence ◽  
Object Control ◽  
Third Grade Students ◽  
Fourth Grade Students ◽  
Low Levels ◽  
And Gender ◽  
Better Than

  Este estudio busca determinar los niveles de competencia motriz de estudiantes chilenos y las posibles diferencias en función del grado y del sexo. Participaron 377 estudiantes (37.7% niñas) de tercer y cuarto básico. La competencia motriz fue evaluada a través del test MOBAK 3-4. Se encontraron bajos niveles de competencia motriz. Los estudiantes de cuarto grado presentan un mejor desempeño motriz que los de tercero. Los niños presentan un mayor desempeño que las niñas en control de objetos, mientras que las niñas obtienen puntajes más altos que los niños en control del cuerpo, aunque con un tamaño del efecto irrelevante. Al contrastar estos resultados con los objetivos del currículum, muchos estudiantes no alcanzan los aprendizajes esperados, siendo necesario poner mayor énfasis en el fomento de la competencia motriz.  Abstract. This study aims to determine the levels of motor competence of Chilean students and possible differences according to grade and gender. 377 students (37.7% girls) of the third and fourth grade participated in the study. Motor competence was evaluated through the MOBAK 3-4 test. Low levels of motor competence were found. Fourth grade students showed a better motor performance than third grade students. Boys performed better than girls in object control, while girls scored higher than boys in self-movement, although with an irrelevant effect size. When these results are contrasted with the learning objectives stipulated in the curriculum, many students do not achieve the expected skills, what makes it necessary to place greater emphasis on the promotion of motor competence.

Directional freezing of spermatozoa and embryos

2014 ◽  
Vol 26 (1) ◽  
pp. 83 ◽  
Author(s):  
Amir Arav ◽  
Joseph Saragusty
Keyword(s):  
Cooling Rate ◽  
Drop Size ◽  
Mechanical Damage ◽  
Rapid Freezing ◽  
Wild Animals ◽  
Microscope Slide ◽  
Freezing Method ◽  
Wide Range ◽  
Sexed Semen ◽  
Directional Freezing

Directional freezing is based on a simple thermodynamic principle whereby the sample is moved through a predetermined temperature gradient at a velocity that determines the cooling rate. Directional freezing permits a precise and uniform cooling rate in small- and large-volume samples. It avoids supercooling and reduces mechanical damage caused by crystallisation. Directional solidification was used to date for slow and rapid freezing, as well as for vitrification of oocytes and embryos by means of the minimum drop size technique: small drops are placed on a microscope slide that is moved at high velocity from the hot base to the cold base. Sperm samples from a wide range of domestic and wild animals were successfully cryopreserved using the directional freezing method. The bovine sexed semen industry may benefit from the increased survival of spermatozoa after directional freezing.

THE SUSCEPTIBILITY OF SPERMATOZOA TO TEMPERATURE SHOCK

1959 ◽  
Vol 19 (3) ◽  
pp. 211-220 ◽  
Author(s):  
R. G. WALES ◽  
I. G. WHITE
Keyword(s):  
High Temperatures ◽  
Seminal Plasma ◽  
Room Temperature ◽  
Cold Shock ◽  
Differential Staining ◽  
Temperature Shock

SUMMARY The susceptibility of bull, ram, rabbit, dog, human and fowl spermatozoa to cold shock and high temperatures has been assessed. Motility and differential staining were used as criteria. Ram and bull spermatozoa were increasingly affected by cold shock at temperatures below 15° C; other spermatozoa were, however, little affected. Epididymal ram spermatozoa, particularly those with an attached kinoplasmic droplet, were more resistant than ejaculated ones; the addition of seminal plasma had little effect. Second ejaculates from bulls were slightly more resistant than first ejaculates. Washing bull or fowl spermatozoa free of seminal plasma did not influence their susceptibility to cold shock. Five min at 50° C severely depressed the motility of all spermatozoa except those of the fowl which were, however, completely immobilized at 55° C. Most spermatozoa took up stain more readily when mixed with it at high temperatures than when brought back to room temperature and then mixed; this is due to an increase in the toxicity of the stain at high temperatures.

scholarly journals Evaluation of Distributed Collaborative Adaptive Sensing for Detection of Low-Level Circulations and Implications for Severe Weather Warning Operations

2010 ◽  
Vol 25 (1) ◽  
pp. 173-189 ◽  
Author(s):  
J. Brotzge ◽  
K. Hondl ◽  
B. Philips ◽  
L. Lemon ◽  
E. J. Bass ◽  
...  
Keyword(s):  
Severe Weather ◽  
Special Focus ◽  
Test Bed ◽  
Scanning Strategy ◽  
Engineering Research ◽  
Low Level ◽  
Adaptive Sensing ◽  
Low Levels ◽  
Casa System ◽  
Better Than

Abstract The Center for Collaborative Adaptive Sensing of the Atmosphere (CASA) is a multiyear engineering research center established by the National Science Foundation for the development of small, inexpensive, low-power radars designed to improve the scanning of the lowest levels (&lt;3 km AGL) of the atmosphere. Instead of sensing autonomously, CASA radars are designed to operate as a network, collectively adapting to the changing needs of end users and the environment; this network approach to scanning is known as distributed collaborative adaptive sensing (DCAS). DCAS optimizes the low-level volume coverage scanning and maximizes the utility of each scanning cycle. A test bed of four prototype CASA radars was deployed in southwestern Oklahoma in 2006 and operated continuously while in DCAS mode from March through June of 2007. This paper analyzes three convective events observed during April–May 2007, during CASA’s intense operation period (IOP), with a special focus on evaluating the benefits and weaknesses of CASA radar system deployment and DCAS scanning strategy of detecting and tracking low-level circulations. Data collected from nearby Weather Surveillance Radar-1988 Doppler (WSR-88D) and CASA radars are compared for mesoscyclones, misocyclones, and low-level vortices. Initial results indicate that the dense, overlapping coverage at low levels provided by the CASA radars and the high temporal (60 s) resolution provided by DCAS give forecasters more detailed feature continuity and tracking. Moreover, the CASA system is able to resolve a whole class of circulations—misocyclones—far better than the WSR-88Ds. In fact, many of these are probably missed completely by the WSR-88D. The impacts of this increased detail on severe weather warnings are under investigation. Ongoing efforts include enhancing the DCAS data quality and scanning strategy, improving the DCAS data visualization, and developing a robust infrastructure to better support forecast and warning operations.

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