Technical note: how accurate can stalagmite formation temperatures be determined using vapour bubble radius measurements in fluid inclusions?

Stalagmites are natural archives containing detailed information on continental climate variability of the past. Microthermometric measurements of fluid inclusion homogenisation temperatures allow determination of stalagmite formation temperatures by measuring the radius of stable laser-induced vapour bubbles inside the inclusions. A reliable method for precisely measuring the radius of vapour bubbles is presented. The method is applied to stalagmite samples for which the formation temperature is known. An assessment of the bubble radius measurement accuracy and how this error influences the uncertainty in determining the formation temperature is provided. We demonstrate that the nominal homogenisation temperature of a single inclusion can be determined with an accuracy of ±0.25 °C, if the volume of the inclusion is larger than 105 μm3. With this method, we could measure in a proof-of-principle investigation that the formation temperature of 10–20 yr old inclusions in a stalagmite taken from the Milandre cave is 9.87 ± 0.80 °C, while the mean annual surface temperature, that in the case of the Milandre cave correlates well with the cave temperature, was 9.6 ± 0.15 °C, calculated from actual measurements at that time, showing a very good agreement. Formation temperatures of inclusions formed during the last 450 yr are found in a temperature range between 8.4 and 9.6 °C, which corresponds to the calculated average surface temperature. Paleotemperatures can thus be determined within ±1.0 °C

Internal stress as a link between macroscale and mesoscale mechanics

The internal (or residual) stress is among the key notions to describe the state of the systems far from equilibrium. Such stress is invisible on the macroscopic scale where the system is regarded as a blackbox. Yet nonequilibrium macroscopic operations allow to create and observe the internal stress. We present in this lecture some examples of the internal stress and its operations. We describe the memory effect in some detail, the process in which the history of past operations is recalled through the relaxation of internal stress.Comment: 11pages, 2 figures, 7 equations: Refereed notes of the Lectures given at "Morphogenesis through the interplay of nonlinear chemical instabilities and elastic active media" July 2-14 2007. to be published from Springer (NATO series

A Lesson Study on Teaching Impulse and Momentum in the New Normal

Impulse and momentum are basic concepts of mechanics introduced in the K to 12 curricula. Despite its basic concepts, students still have difficulties understanding the topic, especially when they are out of school due to the pandemic. After reopening the gates for face–to–face classes in the Philippines, the researchers found a significant reason to conduct a lesson study to improve teaching strategies on the topic. Lesson study is a development process wherein teachers work collaboratively to improve teachers teaching capacity. This study was conducted at Plaridel National High School with 23 participants from Grade 9 Newton (Set A and B). The research was conducted in two cycles using a four – phase lesson study. The research lesson was implemented using a 4A Model lesson plan and the results were taken from the analysis of the lesson study observation sheets, along with the class proficiency level. The researchers used the following strategies to improve teaching, namely; (1) showing mastery of subject matter, (2) reviewing basic mathematical operations, (3) contextualizing the lesson, (4) allowing students to answer questions in mother tongue, (5) using collaborative activities, (6) giving rewards, and (7) applying proper time management. However, the findings still showed that both sets of students achieved beginning proficiency level. Despite the implementation of these strategies, the students still lack basic knowledge of the topic and mathematical operations, and they struggle to understand it. Thus, it is recommended to plan the lesson effectively, utilize other research instruments, and collect feedback from the students

Non-Adherence in Patients on Peritoneal Dialysis: A Systematic Review

Background: It has been increasingly recognized that non-adherence is an important factor that determines the outcome of peritoneal dialysis (PD) therapy. There is therefore a need to establish the levels of non-adherence to different aspects of the PD regimen (dialysis procedures, medications, and dietary/fluid restrictions). Methods: A systematic review of peer-reviewed literature was performed in PubMed, PsycINFO and CINAHL databases using PRISMA guidelines in May 2013. Publications on non-adherence in PD were selected by two reviewers independently according to predefined inclusion and exclusion criteria. Relevant data on patient characteristics, measures, rates and factors associated with non-adherence were extracted. The quality of studies was also evaluated independently by two reviewers according to a revised version of the Effective Public Health Practice Project assessment tool. Results: The search retrieved 204 studies, of which a total of 25 studies met inclusion criteria. Reported rates of nonadherence varied across studies: 2.6 1353% for dialysis exchanges, 3.9 1385% for medication, and 14.4 1367% for diet/fluid restrictions. Methodological differences in measurement and definition of non-adherence underlie the observed variation. Factors associated with non-adherence that showed a degree of consistency were mostly socio-demographical, such as age, employment status, ethnicity, sex, and time period on PD treatment. Conclusion: Non-adherence to different dimensions of the dialysis regimen appears to be prevalent in PD patients. There is a need for further, high-quality research to explore these factors in more detail, with the aim of informing intervention designs to facilitate adherence in this patient populatio

A non invasive instrument for in vivo dynamic laser light scattering measurement in the human eye

A new optical instrument for `in vivo' analysis of ocular tissue is presented. The instrument is based on the well know dynamic light scattering technique. Using optimal beam shaping the analysis can be achieved in the cornea and in the anterior chamber as well as in the lens and in the vitreous with high spatial resolution and sensitivity. In order to obtain high beam quality, to provide modularity and galvanic insulation of the instrument, monomode optical fibers are used to guide the excitation and the scattered light. Following a description of the instrument, preliminary `in-vivo' measures are discussed in order to asses the performance of the instrument in ophthalmology diagnostic

In vivo dynamic light scattering changes of the vitreous in diabetes mellitus

Purpose. Dynamic light scattering (DLS) is a well known non-invasive diagnostic tool used in the anter or segment. In this study in vivo DLS measurements of the human vitreous have been performed to detect changes during the course of diabetes mellitus both with and without diabetic retinopathy. Material and Methods. 50 diabetes mellitus patients with ocular complications varying form no diabetic retinopathy through to severe diabetic retnopathy were examined using DLS techniques. Measurements were performed at different topographical locations of the vitreous, the retrovitreal space and the retina. The results were compared to measurements of 50 normal subjects. Results. The autocorrelation function obtained from the DLS signal in the normal vitreous exhibits two peaks which correspond to the contribution from macromolecules These peaks were found to alter, either in applitude or location, during the course of diabetic retinopathy. The degree and form of these alterations was correlated to the severity of the ocular complicatons in the structures investigated. DLS measurements in the cornea exhibited similar effects to those made in the vitreous. Conclusions. DLS is capable of detecting the changes of the vitreous associated with diabetes mellitus. Moreover, due to the close correlation of the DLS results with the severity of viteo-retinal changes, DLS may serve as an important tool for the early diagnosis and monitoring of ocular complications due to diabetes mellitus

Design and performance of a new ophthalmic instrument for dynamic light-scattering measurements in the human eye

A new optical instrument for in vivo dynamic light-scattering measurements in the human eye isdescribed. The instrument is based on the well-known dynamic light-scattering technique. Resultscan be obtained from the anterior as well as the posterior segment with high spatial resolution andsensitivity. This instrument allows, to our knowledge for the first time, in vivo measurements ofdynamic light scattering to be performed in the vitreous. Interesting performance is obtained usingsingle-mode optical fibers to guide the excitation and the scattered light resulting in a modular,compact system with high-beam quality and electrical insulation of the patient. The instrumentdemonstrates good safety characteristics ~the optical power impinging the patient’s eye is 36 timesbelow the maximum laser power at the cornea, recommended for intrapupil exposure by ANSIstandard!. To demonstrate the possible clinical use of this technique, in vivo measurements weremade and the results compared with the known eye pathologies