Cold Wind Research Articles

Dust entrainment in magnetically and thermally driven disk winds

Context.Magnetically and thermally driven disk winds have gained popularity in the light of the current paradigm of low viscosities in protoplanetary disks that nevertheless present large accretion rates even in the presence of inner cavities. The possibility of dust entrainment in these winds may explain recent scattered light observations and constitutes a way of dust transport towards outer regions of the disk.Aims.We aim to study the dust dynamics in these winds and explore the differences between photoevaporation and magnetically driven disk winds in this regard. We quantify maximum entrainable grain sizes, the flow angle, and the general detectability of such dusty winds.Methods.We used the FARGO3D code to perform global, 2.5D axisymmetric, nonideal MHD simulations including ohmic and ambipolar diffusion. Dust was treated as a pressureless fluid. Synthetic observations were created with the radiative transfer code RADMC-3D.Results.We find a significant difference in the dust entrainment efficiency of warm, ionized winds such as photoevaporation and magnetic winds including X-ray and extreme ultraviolet heating compared to cold magnetic winds. The maximum entrainable grain size varies from 3 μm−6 μm for ionized winds to 1 μm for cold magnetic winds. The dust flow angle decreases rapidly with increasing grain size. Dust grains in cold magnetic winds tend to flow along a shallower angle compared to the warm, ionized winds. With increasing distance to the central star, the dust entrainment efficiency decreases. Larger values of the turbulent viscosity increase the maximum grain size radius of possible dust entrainment. Our simulations indicate that diminishing dust content in the outer regions of the wind can be mainly attributed to the dust settling in the disk. The Stokes number along the wind launching front stays constant in the outer region. In the synthetic images, the dusty wind appears as a faint, conical emission region which is brighter for a cold magnetic wind.

Assessment of the cooling effect of the body and frostbite of open areas of the body in the Arctic condition

In conditions of arctic cold, individual protection means do not always provide sufficient efficiency when performing a number of works. The risk of body cooling (according to the index of cold wind — ICH) and frostbite of open areas of the body (according to the integral indicator of body cooling (IPCOO) and the equivalent temperature (EquT) was determined. EquT was calculated by Sayple and an improved formula. Evaluation was carried out according to meteorological data obtained at Cape Chelyuskin and Dikson Island. On Chelyuskin, according to IHV, year-round warming of the body is required. According to the average monthly indicators, the risk of cooling the body in winter clothes in April-May and October-November. In December-March, the HI values significantly exceed the critical values. Warming of the body on Dikson 10 months a year, risk zone — 8 months: cooling — autumn and March, April, critical cooling — winter months. According to EquT, the duration of the frostbite period for 1 min is longer — 5–6 months at temperatures from –27.0 ± 0.4 0 С to –45.4 ± 0.9 / –38.8 ± 0.5 0 С. On Dikson, the duration of the period of critical risk is 3 months, moderate — 7 months. According to EqT, there is a high risk of frostbite for 4–6 months at temperatures from –29.8 ± 0.3 0 С to –42.3 ± 0.7 / –34.3 ± 0.4 0 С. Taking into account the wind speed, which affects the thermal insulation properties of clothing, it should be assumed that, according to the average wind data, a high health hazard persists for 5–6 months on Chelyuskin, and 4–6 months on Dikson. insignificant danger persists all year round. The duration of the high hazard period is probably longer when assessing the effect of maximum wind and minimum temperature.

Filamentation of fast radio bursts in magnetar winds

ABSTRACT Magnetars are the most promising progenitors of fast radio bursts (FRBs). Strong radio waves propagating through the magnetar wind are subject to non-linear effects, including modulation/filamentation instabilities. We derive the dispersion relation for modulations of strong waves propagating in magnetically dominated pair plasmas focusing on dimensionless strength parameters a0 ≲ 1, and discuss implications for FRBs. As an effect of the instability, the FRB-radiation intensity develops sheets perpendicular to the direction of the wind magnetic field. When the FRB front expands outside the radius where the instability ends, the radiation sheets are scattered due to diffraction. The FRB-scattering time-scale depends on the properties of the magnetar wind. In a cold wind, the typical scattering time-scale is τsc ∼ $\mu$s–ms at the frequency $\nu \sim 1\, {\rm GHz}$. The scattering time-scale increases at low frequencies, with the scaling τsc ∝ ν−2. The frequency-dependent broadening of the brightest pulse of FRB 181112 is consistent with this scaling. From the scattering time-scale of the pulse, one can estimate that the wind Lorentz factor is larger than a few tens. In a warm wind, the scattering time-scale can approach $\tau _{\rm sc}\sim \, {\rm ns}$. Then scattering produces a frequency modulation of the observed intensity with a large bandwidth, $\Delta \nu \sim 1/\tau _{\rm sc}\gtrsim 100\, {\rm MHz}$. Broad-band frequency modulations observed in FRBs could be due to scattering in a warm magnetar wind.

A climate perspective of the quasi-stationary front in southwestern China: structure, variation and impact

Yunnan–Guizhou quasi-stationary front (YGQSF) is a unique weather phenomenon that frequently occurs during the winter half year over the Yunnan–Guizhou Plateau in southwestern China. Most of the previous studies analyzed it only with synoptic cases. This study investigates the structure, variation, and impact of this front from a climate perspective, using long-term high-resolution atmospheric reanalyses and high-density station records for 1981–2016. An objective method quantifying YGQSF is proposed and three indexes are defined to measure its intensity, frequency, and location, respectively, with horizontal gradient of air potential temperature at a terrain-following level of sigma 0.995. With these indexes, climatological structure, subseasonal variability as well as climatic impact of the front are comprehensively examined. In climatology, YGQSF as a north–south-oriented low-level front is found to occur the most frequently during January–February–March, determined predominately by the coldness from the east of the front. The structure of the front identified essentially reflects an obstruction of high-terrain Yunnan (the western part of the plateau) to the low-level cold air mass, which makes near-surface cold northeasterly winds cease westward intruding and veer upward over relatively low-terrain Guizhou, transporting moisture upward and forming low clouds. A sharp climate contrast is thus formed between two sides of the front: cold, sunless, and continuously rainy Guizhou versus warm and sunny Yunnan. Furthermore, the front features significant subseasonal variations with periods at around 30 days and 60 days largely in its intensity. Anomalously strong YGQSF events which are caused 75% by the cold anomaly from the east but no more than 17% by the warm anomaly from the west yield different anomalous structures, but consistently amplify the sharp climate contrast between Yunnan and Guizhou.

Clinical spectrum and geographic distribution of keratitis fugax hereditaria caused by the pathogenic variant c.61G>C in NLRP3

AbstractPurposeTo chart clinical findings in individuals with keratitis fugax hereditaria (KFH) and the geographic distribution of their ancestors.MethodsPatient population included 84 Finnish patients (55% female) from 25 families with the pathogenic NLRP3 variant c.61G>C. Procedures and main outcome measures were Sanger sequencing, clinical examination, corneal imaging, and a questionnaire regarding symptoms, quality‐of‐life, treatment, and comorbidities.ResultsThe oldest members in each family were born in Ostrobothnia in Western Finland or Southwestern Finland with historical ties to Sweden. One carrier was asymptomatic. Most (77%) experienced their first attack between 6 and 20 years of age. Three quarters had unilateral attacks 3‐5 times annually, primarily triggered by cold wind or air, or stress. Eighty percent reported ocular pain (median, 7 on scale 1‐10), conjunctival injection, photophobia, foreign body sensation, and tearing during attacks. Visual blur occurred 75% and 91% during and after the attack, respectively, for 1 day to 2 months (median, 10 days). Forty‐seven percent had corneal oval opacities with irregular tomography patterns and mild to moderate decrease (20/60 or better) in best‐corrected visual acuity that improved with scleral contact lenses. Except for headache in 40%, systemic symptoms were absent during the attacks.ConclusionsSymptoms and signs of KFH are restricted to the anterior segment of the eye, and they vary widely between individuals. We recommend scleral contact lenses as first‐line treatment for reduced vision. Allele frequencies suggest that KFH goes unrecognized in Sweden and populations with Scandinavian heritage.

Transport Path of Cold‐Dense Plasmas in the Dusk Magnetotail Plasma Sheet: MMS Observations

AbstractThe near‐Earth plasma sheet becomes cold and dense under northward interplanetary magnetic field (IMF) condition, which suggests efficient solar wind plasma entry into the magnetosphere across the magnetopause for northward IMF and a possible contribution of ionospheric oxygen ion outflow. The cold and dense characteristics of the plasma sheet are more evident in the magnetotail flank regions that are the interface between cold solar wind plasma and hot magnetospheric plasma. Several physical mechanisms have been proposed to explain the solar wind plasma entry across the magnetopause and resultant formation of the cold‐dense plasma sheet (CDPS) in the tail flank regions. However, the transport path of the cold‐dense plasma inside the magnetotail has not been understood yet. Here, we present a case study of the CDPS in the dusk magnetotail by magnetospheric multiscale (MMS) spacecraft under strongly northward IMF and high‐density solar wind conditions. The ion distribution function consists of high‐ and low‐energy components, and the low‐energy one intermittently shows energy dispersion in the directions parallel and antiparallel to the local magnetic field. The time‐of‐flight analysis of the energy‐dispersed low‐energy ions suggests that these ions originate in the region farther down the tail, move along the magnetic field toward the ionosphere and then come back to the magnetotail by the mirror reflection. The pitch‐angle dispersion analysis gives consistent results on the traveling time and path length of the energy‐dispersed ions. Based on these observations, we discuss possible generation mechanisms of the energy‐dispersed structure of the low‐energy ions during the northward IMF.

Roles of Terrain, Surface Roughness, and Cold Pool Outflows in an Extreme Rainfall Event Over the Coastal Region of South China

AbstractAn extreme rainfall event with maximum 12 hr accumulated rainfall of 464.8 mm associated with a quasi‐stationary mesoscale convective system occurred over the western coastal region of South China in June 2017. An observational analysis shows that early convective storms were initiated near the mountains and moved northeastwards. Moreover, a convergence line between cold northerly winds and warm southerly winds in the lower levels was formed, which favored the development of the quasi‐stationary system. Cold northerly winds were associated with land breeze, downslope winds as well as previous rainfall during earlier period, and cold pool outflows during later period. Cloud‐resolving simulations were performed to examine the roles of terrain, land‐sea surface roughness contrast, and cold pool outflows in the formation of heavy rainfall. Results demonstrate that land‐sea surface roughness contrast and mountains in the middle of Yangjiang and Jiangmen facilitated the formation of the convergence line during earlier period, and cold pool outflows sustained it during later period. Besides orographic lifting, coastal hills helped reduce the stability. Mountains in the middle of Yangjiang hindered the movement of the convective system, without which the associated heavy rainfall would shift farther north. Mt. Tianlu with westward concave morphology played a vital role in the formation of local convergence and the concentration of heavy rainfall. Without it, the total rainfall in the region of interest was reduced. This study suggests the importance of representing processes associated with the complex underlying surface in models for the prediction of heavy rainfall in coastal regions.

Spatial-temporal characteristics of particulate matters and different formation mechanisms of four typical haze cases in a mountain city

The mechanisms by which pollution forms and acts in mountain cities are unique and remain unclear owing to terrain and meteorological conditions in the mountains. This study investigates the pollution characteristics in Chongqing, a typical mountain city, over the period from 2013 to 2017. Routine observed surface meteorological data, CALIPSO data, ERA5 reanalysis data and the backward trajectory calculation were used for analysis and comparison among four typical pollution cases. The results can be summarized as follows: (1) Pollutants in firework and unfavorable weather condition case mainly originated from local emissions. Anthropogenic aerosols that were characterized by spherical and small particles were detected, which contributed to the higher atmospheric scattering ability. Meanwhile, high humidity was beneficial to hygroscopic growth, resulting in a mixture of haze and fog forming low-visibility conditions. The strong inversion of the upper-layer and the presence of high mountains meant that local pollutants became confined within the basin region, leading to the formation and maintenance of pollution. The important roles of the weather conditions that are associated with mountains, such as cold air damming, low-level jet, valley and gap wind, were also revealed by the variable pollution conditions. (2) Airflow originating from Guizhou, Guangxi, and Hunan, where numerous fire points were detected, transported pollutants that were released from straw burning through upper-lower layer transport to the basin during the straw burning case. The aerosols detected showed low depolarization but a high color ratio, which are the typical characteristics of smoke. The inversion layer did not cover the entire basin, indicating that smoke aerosols were transported by downdraft to mix with local pollutants. (3) During the dust case, large amounts of dust aerosols were detected reaching from the surface to the troposphere, with a special double-layer structure. A lower depolarization ratio but stronger scattering ability was observed for the dust aerosols above the study region, which was attributed to mixing with other aerosols and chemical processes. Secondary circulation occurred when the inversion layer was at around 700 hPa, bringing dust aerosols from around 850 hPa to the surface. This study provides an understanding of the optical properties of the various types of aerosols and highlights the importance of weather condition in the formation and maintenance of pollution events. The results emphasize the need for intense vertical measurement in mountain cities.

Clinical Spectrum and Geographic Distribution of Keratitis Fugax Hereditaria Caused by the Pathogenic Variant c.61G>C in NLRP3

To chart clinical findings in individuals with keratitis fugax hereditaria (KFH) and the geographic distribution of their ancestors. A prospective cross-sectional study. This study took place in a tertiary referral center with a cohort of 84 Finnish patients (55% female) from 25 families with the pathogenic nucleotide-binding domain, leucine-rich repeat (NLR) family pyrin domain containing 3 (NLRP3) variant c.61G>C. Observation procedures and main outcome measures were Sanger sequencing, clinical examination, corneal imaging, and a questionnaire regarding symptoms, quality of life, treatment, and comorbidities. The oldest members in each family were born in Ostrobothnia in Western Finland or in Southwestern Finland with historical ties to Sweden. One carrier was asymptomatic. Most (77%, 46/60) experienced their first attack between age 6 and 20 years. Three-quarters had unilateral attacks 3 to 5 times annually, primarily triggered by cold wind or air, or stress. Eighty percent (48/60) reported ocular pain (median, 7 on scale 1-10), conjunctival injection, photophobia, foreign body sensation, and tearing during attacks. Visual blur occurred in 75% (45/60) and 91% (55/60) during and after the attack, respectively, for a median of 10 days (range, 1 day-2 months). Forty-seven percent (39/60) had corneal oval opacities with irregular tomography patterns and mild to moderate decrease (20/60 or better) in best-corrected visual acuity that improved with scleral contact lenses. Except for headache in 40%, systemic symptoms were absent during the attacks. Symptoms and signs of KFH are restricted to the anterior segment of the eye and vary widely between individuals. We recommend scleral contact lenses as the first-line treatment for reduced vision. Allele frequencies suggest that KFH goes unrecognized in Sweden and populations with Scandinavian heritage.

Anticipation Mechanism for Cold Wave: Forecast Based Financing a Case Study in the Peruvian Andes

In June 2018, the Peruvian provinces of Arequipa and Puno in the southern Andean region were affected by heavy snowfall, which caused severe damage to people and livelihoods in several communities. Using the Forecast-based Financing approach, the Peruvian Red Cross implemented its pre-defined early action protocol before this event, after receiving an extreme snowfall warning (Level 4) from the Peruvian meteorological service. Here, we provide a case study of the approach and event itself, documenting the decision-making thresholds as well as the actions taken. This warning activated the thresholds established in the protocol, and Peruvian Red Cross prioritized 10 communities for pre-disaster support based on the forecasted severity of the event in combination with vulnerability and exposure information. The activation took place 2 days before the extreme snowfall in the communities, and the Red Cross distributed veterinary kits for 50 heads of cattle per family, tarpaulins, tool kits to install a temporary awning for alpacas to protect them from the cold wind and snow, protection kits for alpaca herders and warm clothing for children under five, pregnant women, the elderly, and people with chronic and infectious diseases in 430 highly vulnerable households. This article presents the results of a household survey following the impact of the extreme snowfall. We document the early actions taken by these communities to protect their livelihoods, health, and assets. The evaluation also presents descriptive statistics of household-level outcomes for households receiving pre-snowfall support and those that did not receive any intervention or only received post-disaster assistance. While most households took action to protect their assets, there were fewer extreme losses of alpaca herds reported in the communities who received the early support, and these communities also reported fewer adults suffering from respiratory illnesses. More in-depth research on this type of early action is necessary on a wider scale, especially to evaluate the utility of different support measures and the necessary quantity of support needed. This case study can inform government, civil society, and humanitarian actors of how early action is happening before disasters occur and provide a direction for further investment in research and practice to make use of hydro-meteorological forecasts for the benefit of the most vulnerable.

The Key Role of Cold Ionospheric Ions As a Source of Hot Magnetospheric Plasma and As a Driver of the Dynamics of Substorms and Storms

The solar wind has been seen as the major source of hot magnetospheric plasma since the early 1960’s. More recent theoretical and observational studies have shown that the cold (few eV) polar wind and warmer polar cusp plasma that flow continuously upward from the ionosphere can be a very significant source of ions in the magnetosphere and can become accelerated to the energies characteristic of the plasma sheet, ring current, and warm plasma cloak. Previous studies have also shown the presence of solar wind ions in these magnetospheric regions. These studies are based principally on proxy measurements of the ratios of He++/H+ and the high charge states of O+/H+. The resultant admixture of ionospheric ions and solar wind ions that results has been difficult to quantify, since the dominant H+ ions originating in the ionosphere and solar wind are indistinguishable. The ionospheric ions are already inside the magnetosphere and are filling it from the inside out with direct access from the ionosphere to the center of the magnetotail. The solar wind ions on the other hand must gain access through the outer boundaries of the magnetosphere, filling the magnetosphere from the outside in. These solar wind particles must then diffuse or drift from the flanks of the magnetosphere to the near-midnight reconnection region of the tail which takes more time to reach (hours) than the continuously large outflowing ionospheric polar wind (10’s of min). In this paper we examine the magnetospheric filling using the trajectories of the different ion sources to unravel the intermixing process rather than trying to interpret only the proxy ratios. We compare the timing of the access of the ionospheric and solar wind sources and we use new merged ionosphere-magnetosphere multi-fluid MHD modeling to separate and compare the ionospheric and solar wind H+ source strengths. The rapid access of the initially cold polar wind and warm polar cusp ions flowing down-tail in the lobes into the mid-plane of the magnetotail, suggests that, coupled with a southward turning of the IMF Bz, these ions can play a key triggering role in the onset of substorms and subsequent large storms.

Photoelectron Sheath and Plasma Charging on the Lunar Surface: Semianalytic Solutions and Fully-Kinetic Particle-in-Cell Simulations

This article presents the derivation of semianalytic solutions to a new 1-D photoelectron sheath model near the lunar surface. The plasma species include the cold solar wind protons, drifting Maxwellian solar wind electrons, and Maxwellian photoelectrons emitted from the surface. The semianalytic model is then numerically solved to obtain profiles of quantities of interest as functions of the vertical distance from the surface. A fully-kinetic 3-D finite-difference (FD) particle-in-cell (PIC) code is then utilized to simulate the 1-D photoelectron sheath and the results agree well with the numerical solution to the semianalytic model. A <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\kappa $ </tex-math></inline-formula> -distribution for solar wind electrons is also implemented to the FD-PIC code to compare with the Maxwellian distribution. Results show that photoelectron sheath may reach as high as close to 100 m above the illuminated flat lunar surface near the terminator region and up to about 50 m near the equator region. Our results show that under average solar wind condition, the photoelectron sheath profiles obtained with Maxwellian and <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\kappa $ </tex-math></inline-formula> -distribution (with <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\kappa = 4.5$ </tex-math></inline-formula> ) are very close for 1-D numerical results.

Diurnal Cycle of Tropical Oceanic Mesoscale Cold Pools

AbstractTropical convection regimes range from deep organized to shallow convective systems. Mesoscale processes such as cold pools within tropical convective systems can play a significant role in the evolution of convection over land and open ocean. Although cold pools are widely observed, their diurnal properties are not well understood over tropical oceans and land. The oceanic cold pool identification metric applied herein uses the gradient feature (GF) technique and is compared with diurnally-resolved buoy-identified thermal cold pools. This study provides a first-ever diurnal climatology of GF number, area, and attributed TRMM 3B42 precipitation using a space-borne scatterometer (RapidScat). Buoy data over the Pacific, Atlantic, and Indian Ocean have been used to validate and examine the RapidScat-identified diurnal cycle of GF number and precipitation. Buoy-observed cold pool duration, precipitation, temperature, and wind speed is analyzed to understand the in situ cold pool properties over tropical oceans. GF- and buoy-observed cold pool number and precipitation exhibits a similar bimodal diurnal variability with a morning and afternoon maxima, thus establishing confidence in using GF as a proxy to observe cold pools over tropical oceans. The morning peak is attributed to cold pools associated with deep moist convection while the afternoon peak is related to shallower clouds in relatively drier environments resulting in smaller cold pools over global tropical oceans.

The quantitative comparison of contributions from vapour and temperature to midsummer precipitation in China under the influence of spring heat source over Tibet Plateau

AbstractThe thermal forcing of the Tibet Plateau (TP) causes circulation anomalies that may affect the East Asian monsoon. Hence, summer precipitation in China has a close relation to the previous heat source over TP. The saturation of the atmosphere is the precondition of precipitation, so variations of vapour and temperature adjust the generation of precipitation synergistically. The heating of TP exerts impacts on summer precipitation in China, essentially, through modulating vapour and temperature. The goal of this study is to identify whether the variations of temperature or vapour dominate in the end. Besides, according to the heating characteristics over TP, a more accurate area of spring (March–May) heat source is chosen to indicate the midsummer (July) precipitation in China. The configuration of contributions of temperature and vapour can be divided into two cases. One is that vapour and temperature both increase or decrease, so they play inverse roles. It is easy to find the dominant element in this circumstance. The other is that vapour and temperature have concurrent effects. In this case, their significances need to be further compared. The method based on the linkage of the precipitation and relative humidity is used to quantitatively compare the effects of temperature and vapour. The results are robust and can complement the qualitative analysis with circulations and temperature. In years that there is intense heating on west TP, the Yangtze River basin (YZRB) is controlled by more vapour transport from oceans. The downstream of the Yellow River basin (YLRB) is affected by the dry and cold northerly winds. Dominance analysis shows that vapour general plays a more important role in two major river basins. Maybe not exactly coincide with someone's envision, not all the places are dominated by the vapour. Around northeast China, temperature contributes little more than vapour.

AN ASSESSMENT OF SINGLE-SIDED NATURAL VENTILATION POTENTIAL OF FORT BEAUFORT, SOUTH AFRICA

Natural Ventilation Potential (NVP) is the possibility to ensure acceptable indoor air quality and thermal comfort through natural ventilation only. Natural ventilation is possible if the building envelope is strategically oriented in such a way that the occupied zone can harvest relevant quantities of wind and solar commensurate with seasonal needs. Strategic orientation of the building envelope is a requirement that calls for a site specific natural ventilation potential assessment prior to construction. However, site specific natural ventilation assessment may increase construction costs and even delay the construction exercise. Knowledge of the Natural Ventilation Potential of the host region is therefore fundamental as it gives an overview of how the ventilation system will perform under different weather conditions. The paper presents an assessment of the natural ventilation potential of Fort Beaufort and identifies ideal geometrical orientation of buildings for optimum use of wind and solar energy for natural ventilation. The Pressure Difference Pascal Hours concept was used to quantify natural ventilation potential of Fort Beaufort. It was observed that inlet openings should be concentrated on the South while outlets should be on the North for optimum wind induced natural ventilation. Also, the inlet openings should be avoided in the range 230o-260o so as to protect occupants from cold winter winds but concentrated within 160o-185o so that occupants can enjoy the cooling summer winds. Average seasonal NVP values are all positive therefore, meteorological conditions for Fort Beaufort are suitable for natural ventilation.

Cold Pain Causes the Greatest Drop in Microvascular Blood Flow in Sickle Cell Disease Subjects and Normal Controls Exposed to Graded Thermal Stimuli

Background: Painful vaso-occlusive crises (VOC) are a frequent and debilitating complication of sickle cell disease (SCD). The exact mechanism of transition from steady state to VOC is not well understood although it is thought to occur due to progressive blockage of the microvasculature with rigid sickle shaped red blood cells. Thus, any trigger that decreases the microvascular blood flow increases the red blood cell transit time and can promote entrapment of sickled cells in the microvasculature and progression to VOC. Environmental factors such as exposure to cold wind and changes in weather are common triggers of VOC and have been shown to be associated with increased frequency of hospitalizations for pain in patients with SCD. There is limited experimental data in literature on the physiologic effects of these factors on peripheral perfusion in SCD.Objective: To study the effect of graded thermal stimuli on the peripheral microvascular blood flow in SCD.Methods: 17 SCD and 11 control (healthy or sickle trait) subjects aging 13 to 39 years were exposed to graded thermal stimuli via TSA- II Neurosensory analyzer thermode that was placed on the thenar eminence. Individual threshold temperatures for heat and cold detection, heat and cold pain were applied and changes in the microvascular blood flow were measured on the contralateral thumb using photo-plethysmography (PPG).The vasoconstriction response within the complex microvascular blood flow signal was detected using cross-correlation technique. In order to quantify the vasoconstriction response, we calculated mean blood flow (MBF) from the PPG amplitude during each of these stimuli and compared to the MBF at baseline.Results: Cross correlation analysis showed that cold pain caused significant vasoconstriction response in 75% of the subjects, followed by heat pain (57%), cold detection (39%) and heat detection (18%).There was a significant drop in the MBF during cold pain, heat pain and heat detection when compared to baseline MBF (p <0.001) where cold pain caused the greatest drop in MBF (Figure 1). SCD subjects trended towards greater percent change in MBF from baseline across all the threshold temperatures but there was no significant difference between the two groups. The average threshold temperatures were comparable across the two groups with no significant differences in thermal sensitivity detected between SCD and controls (Table 1).Conclusions: Exposure to graded thermal stimuli causes a progressive drop in microvascular blood flow with exposure to cold pain eliciting the strongest vasoconstriction response. The vasoconstriction occurred in the contralateral hand at an average of 10 seconds after the stimulus, suggesting a neurally mediated mechanism. Although there was no significant difference in vasoconstriction responses between SCD and controls, the drop in microvascular blood flow in sickle cell patients can increase the likelihood of entrapment of the sickled red blood cells in the microvasculature leading to vaso-occlusion. These findings are consistent with extensive reports in literature that exposure to extremes of cold weather is associated with a higher frequency of VOC. This suggests that neurally mediated decrease in the microvascular blood flow is likely an important factor in the pathophysiology behind cold exposure leading to VOC in SCD. [Display omitted] DisclosuresNo relevant conflicts of interest to declare.

The benefits of ensemble prediction for forecasting an extreme event: The Queensland Floods of February 2019

AbstractFrom late January to early February 2019, a quasi-stationary monsoon depression situated over northeast Australia caused devastating floods. During the first week of February, when the event had its greatest impact in northwest Queensland, record-breaking precipitation accumulations were observed in several locations, accompanied by strong winds, substantial cold maximum temperature anomalies and related wind chill. In spite of the extreme nature of the event, the monthly rainfall outlook for February issued by Australia’s Bureau of Meteorology on 31st January provided no indication of the event. In this study, we evaluate the dynamics of the event and assess how predictable it was across a suite of ensemble model forecasts using the UK Met Office numerical weather prediction (NWP) system, focussing on a one week lead time. In doing so, we demonstrate the skill of the NWP system in predicting the possibility of such an extreme event occurring. We further evaluate the benefits derived from running the ensemble prediction system at higher resolution than used operationally at the Met Office and with a fully coupled dynamical ocean. We show that the primary forecast errors are generated locally, with key sources of these errors including atmosphere-ocean coupling and a known bias associated with the behaviour of the convection scheme around the coast. We note that a relatively low resolution ensemble approach requires limited computing resource, yet has the capacity in this event to provide useful information to decision makers with over aweek’s notice, beyond the duration of many operational deterministic forecasts.

한라산 지역 저온극한 체감온도 발생의 시·공간적 패턴

The purpose of this study is to explore spatio-temporal patterns of extreme low human-sensible temperature (HST) across Mt Halla (1,950m), Korea. To do this, decadal (2011/12-2020/21) averages of daily or hourly windchill index (WCI), which quantifies HST considering the combined effects of low temperature and strong wind, are calculated for 24 weather stations in Mt Halla. Time series of decadal average daily mean show that extreme low HST events with moderate risk level (-27~-10°C) occur in mid-winter (mid-January~early February) around the high mountainous areas of Mt Halla, while such risk does not exist in the low-elevated coastal regions of Jeju Island under subtropical climate. Strong wind around the subalpine climate belt lowers HST by 5°C than air temperature in mid-winter. In extreme cases when the advection of northerly cold wind is intensified by the west high-east low pressure pattern in East Asia, the HST around the peak of Mt Halla can be lowered to high risk level (-39~-28°C) in the early morning times of mid-winter days. These information about mountain bioclimate may help establish mountain extreme climate warning systems, which are needed to protect mountaineers from potential life-threatening accidents caused by extreme low HST events over high mountains such as Mt Halla.

Correlation Knowledge to Hypothermic Handling Practices in Students

Hypothermia is a decrease in core body temperature to &lt;35˚C due to heat loss. Factors causing hypothermia are cold weather, exposure to cold winds at high altitudes, immersion in cold water, and prolonged exposure to cold. Hypothermia is more common in hikers or mapala because they do activities exploring the highlands. The purpose of this study was to determine the relationship between knowledge of hypothermia and the practice of handling hypothermia in Mapala. This study used a correlation study method with a cross-sectional approach. The population in this study were Mapala UNISSULA, UNNES, and USM with a total of 52 students. The sampling technique was purposive sampling, the number of samples of this study was 30 students. The results of the Spearman Rank statistical test obtained a value of ρ value of 0.738 (ρ ≥ 0.05), so it was stated that there was no relationship between knowledge of hypothermia and the practice of handling hypothermia in Nature Lovers Students. Recommendations from research so that mapala members increase their knowledge and practice in handling emergency hypothermia by conducting ongoing training.

One-Eye, Two-Eyes, Three-Eyes

109 CHARLES YU One-Eye, Two-Eyes, Three-Eyes • When a child stays needy until he is fifty— oh mother-eye, oh mother-eye, crush me in— the parent is as strong as a telephone pole. —Anne Sexton, “One-Eye, Two-Eyes, Three-Eyes” e moves back in, a week shy of his fortieth, eighteen years to the day since he moved out. In between, they’d had three divorces (two hers, one his), two bankruptcies (one a piece), two stays in rehab (both his), and one thousand, three hundred and thirteen phone calls. She opens the door, her face expectant. He doesn’t return her look, can’t bear it. He steps into the small living room, his prom picture still angled on the mantle between a jade frog and a porcelain rose. He turns to see, on the opposite wall, a handmade sign she’s taped up: welcome home! Please take that down, he says. She asks if she can make him a plate of food. He doesn’t answer. Goes straight for the cabinet, grabs the first handle. Splashes three fingers of room-temperature gin into a mug. Okay, he says. There are going to be some rules. Yes. His mother laughs. Mine. She takes the mug from him, drains it in one easy gulp. You are not to touch this, she tells him. Not even a drop. Or what? he asks. This time it is her turn to not answer. She tells him to get some rest. He’ll need it. A blanket, folded on the couch. His old pillowcase. He looks out the window. Was that a new tree? He didn’t remember. But it looked like it had been there since before the house even. It looked ancient. ‘ h 110 He wakes in the night. His stomach, empty. He finds bread and meat and cheese, slaps it together. He eats the sandwich in four rough bites while staring through the window. A cold wet wind blows against the tree, the house. The white bread sticks in his throat, unmoving. He cups his hand under the faucet and slurps a few times, forces it down. Full now, or at least no longer hungry, he finds the whiskey, fills his mother ’s mug almost to the top. In her bedroom, he hears her stirring. She calls out to him. You okay? she asks. Go back to sleep, he says. He takes his mug to the window. She’d always been overprotective. Always hovering. Still doing it. Driving him to this. Middle-aged, alone, the sum total of his possessions in the hatchback parked on the street. The wind shifts, the clouds part, and moonlight reveals two men standing by the tree. He freezes. Were they there before? Are they looking at him? They walk toward the window. His head pounding, his stomach heavy and warm, his breath damp and sour. They are at the door. They don’t knock, but he can see them standing there. They are large, tall enough that he can see the tops of their heads through the transom. He stands still, unable to move. From behind him, footsteps. Told you not to drink, his mother says, suddenly in the doorway of her bedroom. There are men outside, he says, his voice small. Get in my room, she tells him. What are you going to do? Never mind that, she says, and she pushes him inside, closes the door. He hears sounds, voices, but everything is carried away in the wind blowing through the front door. ‘ He wakes in the morning to find his mother asleep on the couch. Her hands covered in dried earth, her arms scratched and bleeding. They’re gone, she tells him. Who were they? he asks. 111 I had two sisters. Each of them had a son. Each born with one eye. That sucks, he says. They thought so, too. So they tried to kill you when you were a baby. For my eyes? Yes. What did you do? I told them they couldn’t have them because you would need them. Because one day you would do something with your two eyes that would bring them...