How reliable is measurement of posture during sleep: real-world measurement of body posture and movement during sleep using accelerometers

Objective Understanding sleeping behaviours could improve prevention and treatment of sleep problems and associated health conditions. This study aimed to evaluate a method to assess body posture and movement during sleep using trunk-worn accelerometers for 28 days. Approach Participants (50 adults with low back pain (66% female); aged 32(±9) years) wore two activPAL-micro sensors (thigh, trunk) during their normal daily life for 28 consecutive days. Parameters related to body posture (e.g., time spent lying supine or prone) and movement (e.g., number of turns) during sleep were calculated for each night. Average values for each parameter were identified for different periods, the Spearman-Brown Prophecy Formula was used to estimate the minimum number of nights required to obtain a reliable estimate of each parameter, and repeatability of measures between different weeks was calculated. Main Results Participants spent 8.1(±0.8) hours asleep and most time (44%) was spent in a supine posture. The minimum number of nights required for reliable estimates varied between sleep parameters, range 4-21 nights. The most stable parameters (i.e., requiring less than seven nights) were “average activity”, “no. of turns”, “time spent prone”, and “posture changes in the first hour”. Some measures differed substantially between weeks. Significance Most sleep parameters related to body posture and movement require a week or more of monitoring to provide reliable estimates of behaviour over one month. Notably, one week may not reflect behaviour in another week, and the time varying nature of sleep needs to be considered.

Assessment of diagnostic accuracy of biomarkers to assess lung consolidation in calves with induced bacterial pneumonia using receiver operating characteristic (ROC) curves

Bovine respiratory disease (BRD) is the most economically significant disease for cattle producers in the U.S. Cattle with advanced lung lesions at harvest have reduced average daily gain, yield grades and carcass quality outcomes. The identification of biomarkers and clinical signs that accurately predict lung lesions could benefit livestock producers in determining a BRD prognosis. Receiver operating characteristic (ROC) curves are graphical plots that illustrate the diagnostic ability of a biomarker or clinical sign. Previously we used the area under the ROC curve (AUC) to identify cortisol, hair cortisol and infrared thermography imaging as having acceptable (AUC > 0.7) diagnostic accuracy for detecting pain in cattle. Herein, we used ROC curves to assess the sensitivity and specificity of biomarkers and clinical signs associated with lung lesions after experimentally induced bovine respiratory disease (BRD). We hypothesized pain biomarkers and clinical signs assessed at specific timepoints after induction of BRD could be used to predict lung consolidation at necropsy. Lung consolidation of >10% was retrospectively assigned at necropsy as a true positive indicator of BRD. Calves with a score of <10% were considered negative for BRD. The biomarkers and clinical signs analyzed were serum cortisol; infrared thermography (IRT); mechanical nociceptive threshold (MNT); substance P; kinematic gait analysis; a visual analog scale (VAS); clinical illness score (CIS); computerized lung score (CLS); average activity levels; prostaglandin E2 metabolite (PGEM); serum amyloid A and rectal temperature. A total of 5,122 biomarkers and clinical signs were collected from 26 calves, eighteen of which were inoculated with M. haemolytica. All statistics were performed using JMP Pro 14.0. Results comparing calves with significant lung lesions to those without yielded the best diagnostic accuracy (AUC > 0.75) for right front stride length at 0 h; gait velocity at 32 h; VAS, CIS, average activity and rumination levels, step count and rectal temperature, all at 48 h; PGEM at 72 h; gait distance at 120 h; cortisol at 168 h; and IRT, right front force and serum amyloid A, all at 192 h. These results show ROC analysis can be a useful indicator of the predictive value of pain biomarkers and clinical signs in cattle with induced bacterial pneumonia. AUC values for VAS score, average activity levels, step count, and rectal temperature seemed to yield good diagnostic accuracy (AUC > 0.75) at multiple timepoints while MNT values, substance P concentrations, and CLS did not (all AUC values < 0.75).

Compensatory variability in network parameters enhances memory performance in the Drosophila mushroom body

Neural circuits use homeostatic compensation to achieve consistent behavior despite variability in underlying intrinsic and network parameters. However, it remains unclear how compensation regulates variability across a population of the same type of neurons within an individual and what computational benefits might result from such compensation. We address these questions in the Drosophila mushroom body, the fly’s olfactory memory center. In a computational model, we show that under sparse coding conditions, memory performance is degraded when the mushroom body’s principal neurons, Kenyon cells (KCs), vary realistically in key parameters governing their excitability. However, memory performance is rescued while maintaining realistic variability if parameters compensate for each other to equalize KC average activity. Such compensation can be achieved through both activity-dependent and activity-independent mechanisms. Finally, we show that correlations predicted by our model’s compensatory mechanisms appear in the Drosophila hemibrain connectome. These findings reveal compensatory variability in the mushroom body and describe its computational benefits for associative memory.

Applying in-Situ and Laboratory-based Gamma Spectrometry to Determine Activity Concentration and Distribution of 40K, 226Ra and 232Th in Abeokuta, Southwest Nigeria

The applications of radionuclides are potential sources of health risk and also a concern in the area of nuclear security. It is therefore imperative to determine the presence of the different radionuclides present in the environment at all times, because it is necessary to control and assess the risk level in the environment. The present study compares activity concentrations of the primordial radionuclides 40K, 226Ra and 232Th obtained from laboratory gamma spectrometry measurements with the activity concentrations of the radionuclides as obtained from in-situ measurements. Soil samples were randomly collected from nineteen different points within Abeokuta city ensuring good coverage of the city area. A mobile gamma spectrometry system was used to collect gamma spectra measurements in the field. The obtained values are presented. The ranges of activity concentrations for 40K, 226Ra and 232Th have been found to be 113 – 1975, 5 – 128 and 181 – 3284 Bqkg-1, respectively for laboratory gamma spectrometry and 104 – 1312, 31 – 121 and 104 – 2578 Bqkg-1, respectively for in-situ gamma spectrometry measurements. This study showed that the average activity concentrations of the primordial radionuclides in Abeokuta were much higher than worldwide averages of 400, 35 and 30 Bqkg-1 for 40K, 226Ra and 232Th, respectively. From both methods, 232Th is seen to be the major contributor to the environmental radioactivity of Abeokuta. Good correlations also were deduced between the activity concentration results obtained from laboratory and in-situ gamma spectrometry, which therefore implies a significant relationship between the two methods used in the study. Keywords: In-situ gamma, Gamma spectrometry, Activity concentration, Radionuclides.

Effects of Staged Deployment on the Economics of Global Broadband Internet Satellite Constellations

Historically constellations of communication satellites were designed to function optimally for a specific expected global demand. This estimation is based on assumptions of the number of users and the average activity per user, both of which are highly uncertain. This uncertainty can cause deployed constellations having a capacity far lower than demand, lowering performance and creating opportunity cost, or far higher than demand, potentially bankrupting the company that owns the system as income cannot recoup the initial investment. An approach has previously been proposed wherein a satellite constellation is deployed in stages with each stage increasing the capacity of the constellation through reconfiguration of on-orbit satellites and launch of new satellites. This method has been previously demonstrated to significantly reduce the lifecycle cost of low-earth orbit communication satellite constellations. Recent proposals for satellite constellations to support global broadband internet providers have introduced new technologies as well as new methods of constellation design resulting in far larger constellations than previously envisioned (mega-constellations). Renewed interest and investment in the development global broadband networks demand a return to this topic to investigate its impact in this space.

Penggunaan Media Lembar Balik (Flip Chart) untuk Meningkatkan Hasil Belajar Kognitif Siswa dalam Pembelajaran Tematik

This study aims to describe the differences in students' cognitive learning outcomes between those who use flip chart media and those who use pictures media. This research is a Classroom Action Research (CAR) through two cycles and in each cycle consists of planning, implementation, observation, and reflection. The sample in this study were all students of class V-A MI At-Taqwa Rancaekek. The data collection technique was carried out with a Double Choice test (DC), observation sheets, and interviews. Data analysis techniques used by researchers are descriptive analysis for qualitative data and statistical analysis for quantitative data. This can be seen from the increasing value of the average activity of students and educators in each cycle. Student activities during cycle 1 amounted to 68.8% with less information, then student activity increased in cycle 2 by 84.3% with good information. Then the activities of educators in cycle 1 amounted to 86% with good information, then the activities of educators in cycle 2 amounted to 93% with very good information. Abstrak Penelitian ini bertujuan untuk mendeskripsikan perbedaan hasil belajar kognitif siswa antara yang menggunakan media lembar balik (flip chart) dengan yang menggunakan media gambar. Penelitian ini merupakan Penelitian Tindakan Kelas (PTK) dengan melalui II siklus dan pada setiap siklusnya terdiri dari perencanaan, pelakasanaan, pengamatan, dan refleksi. Sampel dalam penelitian ini adalah seluruh siswa kelas V-A MI At-Taqwa Rancaekek. Teknik pengumpulan data dilakukan dengan tes Piihan Ganda (PG), lembar observasi, dan wawancara. Teknik analisis data yang digunakan peneliti yaitu analisis deskriptif untuk data kualitatif dan analisis statistik untuk data kuantitatif. Hasil penelitian menunjukkan terdapat perbedaan hasil belajar kognitif siswa antara yang menggunakan media lembar balik dengan yang menggunakan media gambar. Hal ini dapat terlihat dari meningkatnya nilai rata-rata aktivitas siswa dan pendidik pada setiap siklus. Aktivitas siswa pada saat siklus 1 sebesar 68,8% dengan keterangan kurang, kemudian aktivitas siswa mengalami peningkatan pada siklus 2 sebesar 84,3% dengan keterangan baik. Kemudian aktivitas pendidik pada siklus 1 sebesar 86% dengan keterangan baik, kemudian aktivitas pendidik pada siklus 2 sebesar 93% dengan keterangan sangat baik.

Activity concentrations of 226^Ra, 232^Th, and 40^K in common maize meal consumed in Namibia and their potential radiation hazards

Gamma spectroscopy was performed to determine the concentrations of 40K, 226Ra and 232Th in maize meal samples collected from shop outlets and open markets in Namibia. The activity concentrations and Excess Lifetime Cancer Risk were determined using a high purity germanium (HPGe) detector. The average activity concentrations of 40K, 226Ra and 232Th were found to be 29.98 ± 4.05, 0.99 ± 0.40 and 0.35 ± 0.08 Bq.kg – 1 in the maize meal samples. The result showed the activity concentrations of 40K significantly higher than the other radionuclides in all the maize meal samples. The average excess life cancer risk varies from 1.33 x 10 – 13 to 6.05 x 10 – 13 for 40K, 8.76 x 10 -13 to 1.19 x 10 – 12 for 232Th and 2.43 x 10 -11 to 2.83 x 10 – 11 for 226Ra. Hence, when compared with internationally acceptable limits, all values fall within the safety limits. Thus, the study concludes that the maize meals consumed in Namibia are radiologically safe for consumption.

Measurement of Natural Radionuclides and Radon Gas Concentration in Surface Soil samples within Jalingo Metropolis, North East Nigeria

Activity concentrations of radionuclides (226Ra, 232Th, 40K) and radon gas in soil samples collected within Jalingo Metropolis were assessed by gamma spectrometric techniques using Na (TI) scintillation detector. The result showed an average activity concentration of 226Ra, 232Th and 40K to be 18.626±7.31 Bq/kg, 16.709±10.96 Bq/kg and,167.935±389.33 Bq/kg. The concentrations of 226Ra, 232Th were lower than the world average value while 40K was far higher that the recommended value.Most people in the study area use soil for building construction therefore, it was necessary to asses if there are any radiological hazards associated with the soil. This was achieved by determining Radium equivalent activity (Raeq), internal hazard index (Hin) and Annual effective dose rate. The result indicates that the indices are within normal limit. The Radon concentration in soil varies 11.126±1.315 kBq/kg to 30.374±3.331 kBq/kg with a mean value of 17.881±7.019 kBq/kg which is within the safety limits. Generally, the result showed that the soil in the study area might not pose major hazard to the members of the public

Movements and residency of Caribbean reef sharks at a remote atoll in Belize, Central America

We investigated spatial use patterns of 77 Caribbean reef sharks ( Carcharhinus perezi ) at Lighthouse Reef Atoll, Belize over 7 years using residency patterns, kernel density (KD) estimation and network analysis. We found a high degree individual variation in spatial use of the atoll, but there were significant differences in residency and activity space between sexes, with females being overall more resident. Ontogenetic shifts in movement and residency were largely limited to females, as the residency index increased and activity space estimates decreased as females matured, while for males there was no relationship between space use or residency and size. KD analysis revealed many mature females were highly resident to discrete locations, and average activity space of the intermediate-sized sharks was significantly larger than that of the adults, but not the smallest sharks. Markov chain analyses indicated that the southwestern portion of the atoll was the most important movement corridor for all sharks. Both the Blue Hole and Half Moon Caye Natural Monuments provide some protection for larger Caribbean reef sharks; however, a gear ban on longlines on the southwestern forereef between Long Caye and the channel entrance to the Blue Hole would maximize the benefits for all sharks.

Radiometric analysis of micas used in many industries and evaluation of radiological hazards

Mica group minerals have been utilized in various industries such as paint, cement, rubber, plastic, paper, automotive, cosmetics, textile, etc. due to their unique electrical, thermal, and mechanical properties. In this study, the radiometric properties of 58 mica samples collected from three quarries operated commercially in Turkey were investigated using gamma-ray spectroscopy with an HPGe detector. The average activity concentrations of 226Ra, 232Th, and 40K analyzed in mica samples were found as 12, 44, and 2763 Bq kg−1, respectively. The radon emanation coefficient and radon mass exhalation rate of mica samples varied from 4 to 22% with an average of 10% and 0.4–5.9 µBq kg−1 s−1 with an average of 2.6 µBq kg−1 s−1, respectively. The radiological hazard caused by the utilization of mica samples as raw materials in the cement and concrete industry was evaluated for adults by calculating the gamma index and annual effective dose due to external exposure indoor. The study results revealed that there are no significant radiological hazards associated with the utilization of mica samples as building raw materials.