The perception threshold of the vestibular Coriolis illusion

BACKGROUND: The vestibular Coriolis illusion is a disorienting sensation that results from a transient head rotation about one axis during sustained body rotation about another axis. Although often used in spatial disorientation training for pilots and laboratory studies on motion sickness, little is known about the minimum required rotation rate to produce the illusion. OBJECTIVE: This study determined the perception threshold associated with the Coriolis illusion. METHODS: Nineteen participants performed a standardized pitching head movement during continuous whole-body yaw rotation at rates varying between 5 to 50 deg/s. The participants reported their motion sensation in relation to three hypothesized perception thresholds: 1) any sense of motion, 2) a sense of rotation, and 3) a sense of rotation and its direction (i.e., the factual Coriolis illusion). The corresponding thresholds were estimated from curves fitted by a generalized linear model. RESULTS: On average threshold 1 was significantly lower (8 deg/s) than thresholds 2 and 3. The latter thresholds did not differ from each other and their pooled value was 10 deg/s. CONCLUSIONS: The Coriolis illusion is perceived at yaw rates exceeding 10 deg/s using a pitching head movement with 40 deg amplitude and 55 deg/s peak velocity. Model analysis shows that this corresponds to an internal rotation vector of 6 deg/s. With this vector the Coriolis perception threshold can be predicted for any other head movement.

The Effect of Ankle Position on Peak Eccentric Force during The Nordic Hamstring Exercise

Peak eccentric force during the Nordic hamstring exercise (NHE) is recognized as a predictive factor for hamstring strain injury (HSI). During the NHE, the knee flexor muscles are eccentrically contracting to resist the knee joint extension. Therefore, it is thought that the action of the gastrocnemius muscle, and thus the ankle position, influences peak eccentric force during the NHE. However, the effect of ankle position on peak eccentric force during the NHE remains unclear. Therefore, we investigated the effect of ankle position on peak eccentric force during the NHE in a cohort of 50 healthy young male rugby players (mean age, 18.7 ± 1.2 years; mean body mass, 81.7 ± 15.2 kg; height, 1.72 ± 0.06 m) with no history of HSI. Each participant performed NHE strength testing with the ankle dorsiflexed or plantarflexed position and was instructed to fall forward as far as possible within 3 s. Peak eccentric force, reported relative to body mass (N/kg), of both legs was recorded, and the mean values of both legs were compared in both ankle positions. The mean peak eccentric force was significantly greater with the ankle plantarflexed position than the dorsiflexed position (3.8 ± 1.1 vs. 3.5 ± 1.1 N/kg, respectively, p = 0.049). These results indicate that ankle position should be carefully considered when measuring peak eccentric force during the NHE and performing NHE training.

Ensemble Forecast of COVID-19 for Vulnerability Assessment and Policy Interventions

The COVID-19 pandemic necessitates forecasts to frame science-informed policies. An accurate forecast of the size and timing of future waves could help public health officials and governments to plan appropriate responses. An ensemble forecast by aggregating different scenarios and models makes the prediction robust and reliable. We present an ensemble forecast for Wave-3 of COVID-19 in the state of Karnataka, India, using the IISc Population Balance Model for infectious disease spread. The reported data of confirmed, recovered, and deceased cases in Karnataka from 1 July 2020 to 4 July 2021 are utilized to tune the model’s parameters. An ensemble forecast is done from 5 July 2021 to 30 June 2022. The ensemble is built with 972 members by varying seven critical parameters that quantify the uncertainty in the spread dynamics (antibody waning, viral mutation) and interventions (pharmaceutical, non-pharmaceutical). The probability of Wave-3, the peak date distribution, and the peak caseload distribution are estimated from the ensemble forecast. Analysis of the ensemble forecast results shows that compliance to COVID-appropriate behaviour, daily vaccination rate, and emergence time of immune-escape new variants are the most significant causal factors that determine the timing and severity of COVID-19 Wave-3. We observe that when compliance to COVID-appropriate behaviour is similar to a lockdown-like situation, the emergence of new immune-escape variants beyond September 2021 is unlikely to induce a new wave. No or partial compliance to COVID-appropriate behaviour makes a new wave inevitable. However, increasing the vaccination rate reduces the active caseload at Wave-3’s peak. If Wave-3 emerges, on average, the daily confirmed caseload of children (Age 0–17 years) could be up to seven times more than the corresponding caseload (4390) at Wave-2’s peak. Therefore, large-scale surveillance, including genome sequencing for early detection of new variants and non-pharmaceutical interventions to improve COVID-Appropriate behaviour, is vital to prevent Wave-3 of COVID-19. Doubling the vaccination rate as of 4 July 2021 to 560K doses per day will reduce the daily confirmed cases even if Wave-3 arises. Consequently, hospitalizations, ICU, and Oxygen requirements can be decreased. Since vaccination is yet to start in children, it is essential to ramp up the public health facilities, including pediatric ICUs to treat MIS-C, by 5-9 times to handle the worst-case situation. From a modeling perspective, capturing the nonlinear dynamics induced by the uncertainties in the causal factors is the key to a successful forecast. Therefore, an effort should be made to build an ensemble forecast that contains multiple models and, more importantly, models that account for causal factor uncertainties.

The Effects of Repetitive Use and Pathological Remodeling on Channelrhodopsin Function in Cardiomyocytes

Aim: Channelrhodopsins (ChRs) are a large family of light-gated ion channels with distinct properties, which is of great importance in the selection of a ChR variant for a given application. However, data to guide such selection for cardiac optogenetic applications are lacking. Therefore, we investigated the functioning of different ChR variants in normal and pathological hypertrophic cardiomyocytes subjected to various illumination protocols.Methods and Results: Isolated neonatal rat ventricular cardiomyocytes (NRVMs) were transduced with lentiviral vectors to express one of the following ChR variants: H134R, CatCh, ReaChR, or GtACR1. NRVMs were treated with phenylephrine (PE) to induce pathological hypertrophy (PE group) or left untreated [control (CTL) group]. In these groups, ChR currents displayed unique and significantly different properties for each ChR variant on activation by a single 1-s light pulse (1 mW/mm2: 470, 565, or 617 nm). The concomitant membrane potential (Vm) responses also showed a ChR variant-specific profile, with GtACR1 causing a slight increase in average Vm during illumination (Vplateau: −38 mV) as compared with a Vplateau > −20 mV for the other ChR variants. On repetitive activation at increasing frequencies (10-ms pulses at 1–10 Hz for 30 s), peak currents, which are important for cardiac pacing, decreased with increasing activation frequencies by 17–78% (p < 0.05), while plateau currents, which are critical for arrhythmia termination, decreased by 10–75% (p < 0.05), both in a variant-specific manner. In contrast, the corresponding Vplateau remained largely stable. Importantly, current properties and Vm responses were not statistically different between the PE and CTL groups, irrespective of the variant used (p > 0.05).Conclusion: Our data show that ChR variants function equally well in cell culture models of healthy and pathologically hypertrophic myocardium but show strong, variant-specific use-dependence. This use-dependent nature of ChR function should be taken into account during the design of cardiac optogenetic studies and the interpretation of the experimental findings thereof.

Inhibition of Ammonia and Hydrogen Sulphide Using Plant Waste Materials for Faecal Sludge Odour Control in Dry Sanitation Toilet Facilities

On-site dry sanitation facilities, although cheaper than wet sanitation systems, suffer from high malodour and insect nuisance as well as poor aesthetics. The high odour deters users from utilizing dry sanitation toilet as an improved facility leading to over 20% open defecation in Sub-Saharan Africa. To address this malodour concern, this study first assessed odour levels, using hydrogen sulphide (H2S) and ammonia (NH3) as indicators, on two (2) dry sanitation facilities (T1 and T2). The potential of using biomass (sawdust, rice husk, moringa leaves, neem seeds), ash (coconut husk, cocoa husk) or biochar (sawdust, rice husk, bamboo) as biocovers to remove or suppress odour from fresh faecal sludge (FS) over a 12-day period was investigated. Results showed high odour levels, beyond and below the threshold limit for unpleasantness for humans on H2S (peak value: T1 = 3.17 ppm; T2 = 0.22 ppm > 0.05 ppm limit) and NH3 (peak value: T1 = 6.88 ppm; T2 = 3.16 ppm < 30 ppm limit), respectively. The biomasses exhibited low pH (acidic = 5-7) whereas the biochars and ashes had higher pHs (basic = 8-13). Acidic biocovers generally reduced NH3 emission significantly (12.5% to 64.8%) whereas basic biocovers were more effective at H2S emission reduction (80.9% to 96.2%). In terms of H2S and NH3 removal, sawdust biochar was the most effective biocover with odour abatement values of 96.2% and 74.7%, respectively. The results suggest that locally available waste plant-based materials, like sawdust, when converted to biochar can serve as a cost-effective and sustainable way to effectively combat odour-related issues associated with dry sanitation facilities to help stop open defecation.

Polycentricity of the City's Metropolitan System as a Factor Increasing Security in Times of Danger - On the Example of Cracow

Service polycentricism, in the face of the pandemic, took on a new significance because of sanitary requirements. Population concentrations in large service centres face a high risk of infection both at their destination and during the trip. Higher-tier services were largely closed during the threat&rsquo;s peak. In this paper, the focus of the study has been placed on the urban scale of a large city&rsquo;s polycentricism as seen through the prism of service concentrations, which, to a degree, are commuter destinations, but primarily act as attractors that are not associated with work&mdash;they satisfy higher-tier service needs. To formulate the investigative apparatus used to study the functio-spatial structure of Cracow. The current threat, as well as the high probability of similar situations happening in the future, will probably lead to changes in behaviour patterns of consumers and service providers in reference to siting. Local service centres that are accessible to pedestrians, due to safety-related considerations, can gain significant popularity.

Pengendalian Kecepatan Crusher Motor Dengan Metode PID Control Menggunakan DCS (Distributed Control System) Pada Proses Ekstraksi Daging Buah Sirsak

Proses ekstrak buah sirsak menjadi bubukterdapat empat proses yaitu crusher (penghancur), spinner(penyaring), mixing (pencampuran), dan drying (pemasanan).Proses crusher (penghancur) digunakan untuk mempermudahpengambilan sari sirsak yang akan di proses menjadi bubuknantinya. Proses ini dilakukan dengan perbandingan 1:1 yaitu1 kg buah sirsak dengan 1 liter air dan menggunakan metodePID control pada kecepatan crusher motor untukmendapatkan waktu yang lebih efisien dengan hasil yang baikdengan kontroler DCS. Prinsip kerja dari sistem crusher iniadalah dengan menstabilkan kecepatan crusher motor sesuaidengan set point yang diberikan pada PC sebagai operatorstation. Dengan hasil nilai parameter Kp, Ki, dan Kddidapatkan dengan perhitungan metode Ziegler Nichols 2dengan nilai Kp=0.6 Ki = 1.5 dan Kd = 0.375 . Memilikidelay time (td) sebesar 0.5 s, rise time (tr) 4 s, peak time (tp) 5s dan Maximum Overshoot (Mo) sebesar 20% pada setpoint1500 rpm dan nilai delay time (td) sebesar 0.7 s, rise time (tr)1 s, peak time (tp) 2.2 s dan Maximum Overshoot (Mo) sebesar40% pada setpoint 2000 rpm.

Penerapan PID Control Untuk Pengendalian Kecepatan Spinner Motor Pada Proses Ekstrak Buah Sirsak Menggunakan DCS (Distributed Control System)

Buah sirsak adalah buah yang memiliki dayasimpan yang pendek dan memiliki kandungan vitamin Ctinggi yang dapat membantu untuk meningkatkan sistemimun. Dengan dijadikannya menjadi bubuk sari sirsak akanmembuat daya simpan yang lebih panjang danmempertahankan kandungan vitamin C didalamnya. Untukproses ekstrak buah sirsak menjadi bubuk terdapat empatproses yaitu crusher (penghancur), spinner (penyaring), mixer(pencampuran), dan dryer (pemasanan). Proses spinner(penyaringan) digunakan untuk mempermudah penyaringansari sirsak yang akan diproses menjadi bubuk nantinya. Padaproses ini kecepatan spinner motor di kontrol menggunakanmetode PID yang terdapat pada DCS (Distributed ControlSystem). Untuk sensor kecepatannya menggunakan sensorrotary encoder. Perancangan kontroller PID menggunakanmetode Ziegler Nichols II menghasilkan Kp = 0.049, Ti = 2.5,dan Td = 0.625. Hasil yang didapatkan antara lain delay time(td) 0.5 s, rise time (tr) 4 s, peak time (tp) 8 s, maximumovershoot (mo) 6.67%, ESS batas atas 3.33%, ESS batasbawah 1,67%, setling time (ts) 21 s. Pengujian dilakukandengan mengubah beban dari tanpa beban namun dengankecepatan yang sama. Semakin besar beban maka waktuspinning semakin lama. Dan pengujian juga dilakukan denganmengubah kecepatan namun dengan beban tetap. Semakincepat putaran spinner motor maka nilai overshoot dan setlingtime semakin kecil.

Penerapan PID Kontrol Untuk Pengendalian Kecepatan Motor DC Stepper Pada Pemposisi Hasil Cetak Filament (3D Printing) Di Gulungan Berbahan Daur Ulang

3D Printing merupakan terobosan yang baru di bidang teknologi, yakni mampu mencetak sesuatu hal yang sama persis di dalam software yang kita inginkan, namun terkadang dalam proses pencetakan sendiri sering terjadi kegagalan, dalam penelitian ini cetakan 3D yang gagal akan di daur ulang lagi sehingga mengurangi biaya produksi. Tujuan dari alat ini yaitu mengontrol kecepatan putaran motor dc stepper agar pada proses penggulungan hasil cetak daur ulang filament 3D Printing tidak menumpuk pada satu sisi. Pemposisi hasil cetak gulungan filament 3D Printing ini dirancang dengan menggunakan beberapa komponen dan mekanik yang terdiri dari : Motor DC Stepper, Sensor Rotary Encoder, Sensor Optocoupler, Sensor Obstacle Infrared dan Sistem pengendalian menggunakan Arduino Mega dan Kontrol PID. Sistem ini berfungsi mengontrol kecepatan putar motor dc stepper hasil dari cetakan filament (3D Printing) diharapkan dari motor stepper dapat selaras dengan motor di penggulungan. Hal ini perlu dilakukan agar hasil dari cetakan filament (3D Printing) pada proses penggulungan tidak menumpuk pada satu sisi. Salah satu metode yang digunakan untuk mengontrol kecepatan motor stepper adalah PID. Perancangan kontroler PID menggunakan kurva reaksi Ziegler Nichols menghasilkan nilai Kp =1,122 Ki = 0,33 dan Kd = 0,95. Hasil yang di dapatkan antara lain rise time (tr) sebesar 0,14 s, time settling (ts) sebesar 55,51 s dan Percent Overshoot (Po) sebesar 38,77%. Respon sistem lebih bagus menggunakan Trial Error dengan rise time (tr) sebesar 1,3 s, settling time (ts) sebesar 18,4 s, peak time (tp) sebesar 2,1 s, dan Percent Overshoot (Po) sebesar 5.8% yang memiliki nilai Kp = 0,8, Ki = 0,42 dan Kd = 0,05. Pengujian sistem dilakukan dengan membandingan 2 Gain yang berbeda. Proses akhir dari alat daur ulang filament (3D Printer) yaitu berat pada penggulungan sudah mencapai 1 kg.

A comparative study of the acute effects of knee brace vs. kinesiotape on selected isokinetic strength variables of the knee muscles

BACKGROUND: Different methods of treatment for preventing knee injuries, enhancing knee strength and minimising post-injury risks have been explored. Among these methods, Kinesio tape (KT) and knee braces (KB) are commonly used. OBJECTIVE : To investigate the acute effects of KT and KB on isokinetic knee strength parameters. METHODS: A total of 15 healthy sedentary male subjects voluntarily participated in the study. Concentric isokinetic knee extension (EX) and flexion (FLX) strength were measured at three sessions: 1. Baseline 2. with KT (’KT’) 3. with KB (’KB’). Tests were performed at 60, 180 and 240∘/s. Peak moment (PM), Hamstring/Quadriceps ratio (HQR), and joint angle at peak moment (JAPM) were measured. RESULTS: ‘KT’ and ‘KB’ were associated with increase in PMEX, PMFLX, HQR at 60 and 240∘/s (p< 0.05) and increased JAPMEX. No significant difference was observed at 180∘/s (p> 0.05). CONCLUSION: In healthy individuals, ‘I’ shape KT and KB positively affect EX and FLX strengths and HQR, especially at low angular velocity.