Linear Pattern Of Increase Research Articles

The Time-Dependent Interfacial Adhesion between Artificial Rock and Fresh Mortar Modified by Nanoclay.

The time-dependent interfacial adhesion between rock and fresh mortar is key for printing concrete linings in mountain tunnels. However, a scientific deficit exists in the time-dependent evolution of the interfacial adhesion, which can cause adhesion failure when printing tunnel lining. Nanoclay has the potential to increase the interfacial adhesion and eliminate the adhesion failure. Before the actual printing of tunnel linings, the time-dependent interfacial adhesion between artificial rock and fresh mortar modified by nanoclay should be understood. This paper studied the time-dependent interfacial adhesion based on fast tack tests, fast shear tests, and isothermal calorimetry tests. With the addition of nanoclay, the maximum tensile stress and the maximum shear stress increased. Compared with a reference series, the maximum interfacial tensile stress in a 0.3% nanoclay series increased by 106% (resting time 1 min) and increased by 209% (resting time 32 min). A two-stage evolution of the interfacial adhesion was found with the addition of nanoclay. In the first stage, the time-dependent interfacial adhesion increased rapidly. A 0.3% NC series showed an increase rate six times higher than that of the reference series. As the matrices aged, the increase rate slowed down and followed a linear pattern of increase, still higher than that of the reference series. The stiffening of fresh matrices resulted in the interface failure mode transition from a ductile failure to a brittle failure. The effect of nanoclay on flocculation and on accelerating the hydration contributed to the time-dependent interfacial adhesion between artificial rock and fresh mortar.

Morphometric analysis of fetal development of Cavia porcellus (Linnaeus, 1758) by ultrasonography—Pilot study

Measurements on the growth process and placental development of the embryo and fetuses of Cavia porcellus were carried out using ultrasonography. Embryo, fetus, and placenta were monitored from Day 15 after mating day to the end of gestation. Based on linear and quadratic regressions, the following morphometric analysis showed a good indicator of the gestational age: placental diameter, biparietal diameter, renal length, and crown rump. The embryonic cardiac beat was first detected at an average of 22.5 days. The placental diameter showed constant increase from beginning of gestation then remained to term and presented a quadratic correlation with gestational age (r2 = 0.89). Mean placental diameter at the end of pregnancy was 3.5 ± 0.23 cm. By Day 30, it was possible to measure biparietal diameter, which followed a linear pattern of increase up to the end of gestation (r2 = 0.95). Mean biparietal diameter in the end of pregnancy was 1.94 ± 0.03 cm. Kidneys were firstly observed on Day 35 as hyperechoic structures without the distinction of medullar and cortical layers, thus the regression model equation between kidney length and gestational age presents a quadratic relationship (r2 = 0.7). The crown rump presented a simple linear growth, starting from 15 days of gestation, displaying a high correlation with the gestational age (r2 = 0.9). The offspring were born after an average gestation of 61.3 days. In this study, we conclude that biparietal diameter, placental diameter, and crown rump are adequate predictive parameters of gestational age in guinea pigs because they present high correlation index.

Implications of climate change on crop water requirements in arid region: An example of Al-Jouf, Saudi Arabia

This study investigated possible implications of climate change on crop water requirements (CWRs) from 2011 to 2050 in Al-Jouf, Saudi Arabia. CWR were predicted for four scenarios: (i) current temperature and rainfall (S1); (ii) temperature in 2050 and current state of rainfall (S2); (iii) rainfall in 2050 and current state of temperature (S3) and (iv) temperature and rainfall in 2050 (S4). Assuming no change in the regulations relating to agriculture and irrigation in future, CWR were predicted to be 873 and 931million cubic meters (MCM) per year for the S1 and S4 scenarios, respectively, indicating an increase of 58 MCM from 2011 to 2050. On an average, 1°C increase in temperature may increase the overall CWR by 2.9% in this region. Following linear pattern of increase, slope of CWR was determined as 1.5MCM/year from 2011, which is equivalent to the CWR of producing approximately 600tons of wheat/year. The increase of CWR was due to the increase in temperature mainly, while the effect of rainfall changes was minimal. Sensitivity analysis on crop growing seasons showed that the shift of wheat growing season might conserve significant amount of groundwater. This study might be useful in explaining the negative effects of climate change on CWR in Al-Jouf and better planning for water resources management.

Biologic Limits of Viability

After completing this article, readers should be able to: 1. Define the gestational range for extremely preterm birth. 2. Explain the difference between possibility and probability in reference to survival following extremely preterm birth. 3. Describe the key lung development required for adequacy of gas exchange. 4. Describe the renal functional limitations for water, sodium, and creatinine homeostasis in the first postnatal week of the extremely preterm infant. 5. List at least one structural and/or functional limitation of at least five organ systems that increases mortality risks for the extremely preterm infant. With the advent of neonatal intensive care in the 1960s, preterm infants born at progressively lower gestational ages began to survive. The progression of the decrement did not follow a recognizable relationship; rather, it was erratic as the knowledge base of neonatal physiology and pathology expanded and new technical capabilities for life support were developed. The most dramatic increase in survival of extremely preterm birth (<26 completed weeks’ gestation) came with the introduction of surfactant replacement therapy in the late 1980s. The increased use of maternal antenatal corticosteroid therapy for induction of lung maturation with threatened preterm delivery following the National Institute of Child Health and Human Development Consensus Conference recommendations in 1994 also contributed to improved survival. Since that time, the survival of infants of gestational ages as low as 22 weeks’ has been reported. The purpose of this article is to review the current understanding of the biologic factors limiting survival potential, particularly as they inform clinical decision-making. Viability or survival potential, when used in reference to a fetus, frequently is used to indicate the possibility for a fetus to be live born and capable of living to a specified endpoint of either a designated time, reaching a certain age or a landmark event, admission to a neonatal intensive care unit, …

Symptomatic pectus deformities of the chest.

Aspects of pulmonary mechanics and exercise tolerance were investigated in 8 young male patients with pectus deformities, 5 of whom presented with the chief complaint of exercise limitation. Results of pulmonary mechanics studies did not adequately explain patient symptoms. Lung volumes were only mildly reduced. There was no evidence of airway obstruction. Measures of lung compliance were normal in 6 patients studied. Results of exercise studies did reveal significant abnormalities in symptomatic and asymptomatic patients; tidal volume at maximal effort expressed as a percentage of vital capacity was diminished, suggesting restriction of ventilation. Oxygen uptakes in the 4 symptomatic patients were normal at lesser work loads but progressively exceeded predicted values at greater work loads, suggesting an abnormally elevated work of breathing during vigorous exertion. Three asymptomatic patients demonstrated a normal linear pattern of increase in oxygen uptake with increasing work load. Respiratory symptoms in some patients with pectus deformities appear to have a physiologic basis. Our data suggest a dynamic restrictive pulmonary process as an explanation for these symptoms.

Teaching Psychiatry to First Year Medical Students in Small Groups: Specification and Evaluation of Goals

A questionnaire was designed to measure the process of education in teaching psychiatry to first year medical students in small groups. A set of goals was delineated by the course instructors and evaluated by student raters from each small group on a week by week basis. A pattern of linear increase in the ratings indicated that the course was definitely helping the students forge a professional identity in dealing with patients but was falling short in teaching students about establishing an alliance with patients and methods of communicating with patients. This assessment technique was not able to answer the larger question about the overall worth of the small group experience in teaching about the doctor-patient relationship, but it did yield information on areas where the course was succeeding and areas where more or different efforts were required.