Activities performed by wildland firefighters are carried out wearing a personal protective equipment (PPE). Although the PPE protects workers from a wide variety of hazards, it may increase their ...physiological response and limit their performance. The aim of this study was to analyze the effect of the protective clothing (PPC) and the rest of the PPE elements (i.e., helmet, neck shroud, gloves, goggles, and mid-calf leather boots) on the wildland firefighters' thermophysiological response during a moderate-intense exercise. Six male wildland firefighters performed, in a counterbalanced order, a 120 min graded exercise test wearing three different clothing configurations: (i) a traditional short sports gear (SG), (ii) a PPC, and (iii) a complete firefighters' PPE. Trials were conducted on separate days at the same time of the day (12:00-15:00 h) and under climate-controlled conditions (∼30°C and ∼30% relative humidity). Heart rate, respiratory gas exchange, gastrointestinal and skin temperature, blood lactate concentration were recorded throughout the tests. Additionally, parameters of heat balance were estimated. Exercise time was shorter (
< 0.001) wearing the PPE (62.4 ± 13.3 min) than with the PPC (115.5 ± 5.0 min) and SG (118.2 ± 20.7 min). The increment of gastrointestinal temperature with the PPE (1.8 ± 0.3°C) was greater (
< 0.05) than the observed in PPC (1.2 ± 0.6°C) and SG (1.0 ± 0.2°C). The use of PPC increased (
< 0.05) subjects' metabolic demand and skin temperature versus SG during the last 20 min of the test. The sweat retention in the PPE (1,045.7 ± 214.7 g) and PPC (978.3 ± 330.6 g) was significantly higher than that obtained in the SG (510.0 ± 210.0 g). Sweat efficiency decreased (
< 0.05) in the following order: PPE (45.6 ± 18.3%), PPC (64.3 ± 7.8%), and SG (79.3 ± 7.0%). These results highlight the importance of the PPE elements in the subjects' thermal strain. The reduction in the sweat evaporation produced by the PPE, together with the ensemble mass caused a substantial increase in the subjects' thermophysiological response. As a consequence the performance was reduced by ∼50%.
Wildland firefighters work under adverse environments (e.g., heat and fire exposure), which contribute to increasing the heat strain. Despite this there is a paucity of knowledge about the thermal ...environment in real wildfire suppression scenarios. Therefore, the main purpose of this study was to characterize the environmental thermal exposure and the risk of heat burn injuries during real wildfire suppression (
= 23). To characterize the wildland firefighter's (
= 5) local thermal exposure, measurements of air temperature and heat flux were performed. Heat flux measurements were made using four thin-planar heat flux sensors. Two were affixed on the outer surface of the garment on the left chest and thigh. Two other sensors were placed on the inner surface of the fabric in parallel to those placed externally. Four thermal classes were defined based on the heat flux across the inner sensors (≤1000, ≤5000, ≤7000, and >7000 W⋅m
). The risk of pain and first-degree burns were calculated using the dose of thermal radiation method. The inner sensors mean and maximum heat flux and environment temperature were 286.7 ± 255.0 and 2370.4 ± 3004.5 W⋅m
and 32.6 ± 8.9 and 78.0 ± 8.9°C, respectively. Approximately 81, 15, and 3.5% of the exposure time the heat flux was ≤1000, >1000-5000, and >5000 W⋅m
, respectively. The highest average and maximum thermal dose values were ∼94 and ∼110 (kW⋅m
)
⋅s. In conclusion, the thermal exposure obtained may be considered light. However, high thermal exposure values may be obtained in punctual moments, which can elicit first-degree burns.
Antimonide-based family holds the potential for developing a new generation of mid-infrared applications. Here, we report on the growth of InSbxAs1-x alloys on n− and p−type GaSb(100) substrates ...varying the Sb mole fraction (x), using the liquid phase epitaxy (LPE) technique. We show that the ternary alloy grown on the n−type GaSb substrate presents higher crystalline quality, thermal diffusivity and interfacial thermal conductivity, as compared to the one grown on pin equation type GaSb substrates which decrease as the Sb mole fraction (x) in the layer increases. Our results demonstrate that the InSbxAs1-x/n−GaSb heterostructure reaches the thermal equilibrium faster than the InSbxAs1-x/p−GaSb structure, with lower roughness, strain, as well as a better chemical abruptness at substrate-layer interface. We also find that the growth mechanism of the InSbxAs1-x alloy is constituted by In−As and In−Sb bonds. Furthermore, the Raman scattering spectra measured at different layer depths evidence that the crystalline quality improves with depth and allow the identification of an intrinsic depletion region. Since the InSbxAs1-x alloy presents a long-range atomic order grown on both n− and p−type GaSb substrates, the phonon-plasmon coupled L− and L+ modes are observed, and from the L+ coupled mode, we obtain the intrinsic carrier concentration and its variation with the Sb mole fraction. Therefore, this work provides important guidance on the structural, thermal, and chemical properties of the surface, bulk and interface of InSbxAs1-x alloys, that should be considered to improve the performance of future devices, such as better heat dissipation.$
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•InSbxAs1−x alloys on n− and p−GaSb substrates were grown by LPE.•Effect of the Sb content on InSbxAs1−x properties was found.•Analysis of surface, bulk and interface of InSbxAs1−x alloys.•Study of thermal diffusivity, interfacial conductivity and growth mechanism.•Study of crystalline quality and intrinsic carrier concentration.
The EPIC focal plane imaging spectrometers on XMM-Newton use CCDs to record the images and spectra of celestial X-ray sources focused by the three X-ray mirrors. There is one camera at the focus of ...each mirror; two of the cameras contain seven MOS CCDs, while the third uses twelve PN CCDs, defining a circular field of view of 30′ diameter in each case. The CCDs were specially developed for EPIC, and combine high quality imaging with spectral resolution close to the Fano limit. A filter wheel carrying three kinds of X-ray transparent light blocking filter, a fully closed, and a fully open position, is fitted to each EPIC instrument. The CCDs are cooled passively and are under full closed loop thermal control. A radio-active source is fitted for internal calibration. Data are processed on-board to save telemetry by removing cosmic ray tracks, and generating X-ray event files; a variety of different instrument modes are available to increase the dynamic range of the instrument and to enable fast timing. The instruments were calibrated using laboratory X-ray beams, and synchrotron generated monochromatic X-ray beams before launch; in-orbit calibration makes use of a variety of celestial X-ray targets. The current calibration is better than 10% over the entire energy range of 0.2 to 10 keV. All three instruments survived launch and are performing nominally in orbit. In particular full field-of-view coverage is available, all electronic modes work, and the energy resolution is close to pre-launch values. Radiation damage is well within pre-launch predictions and does not yet impact on the energy resolution. The scientific results from EPIC amply fulfil pre-launch expectations.
The contribution of mycorrhizal associations to maintaining tree diversity patterns in tropical rain forests is poorly known. Many tropical monodominant trees form ectomycorrhizal (EM) associations, ...and there is evidence that the EM mutualism contributes to the maintenance of monodominance. It is assumed that most other tropical tree species form arbuscular mycorrhizal (AM) associations, and while many mycorrhizal surveys have been done, the mycorrhizal status of numerous tropical tree taxa remains undocumented. In this study, we tested the assumption that most tropical trees form AM associations by sampling root vouchers from tree and liana species in monodominant
Dicymbe corymbosa
forest and an adjacent mixed rain forest in Guyana. Roots were assessed for the presence/absence of AM and EM structures. Of the 142 species of trees and lianas surveyed, three tree species (the monodominant
D. corymbosa
, the grove-forming
D. altsonii
, and the non-dominant
Aldina insignis
) were EM, 137 were exclusively AM, and two were non-mycorrhizal. Both EM and AM structures were observed in
D. corymbosa
and
D. altsonii
. These results provide empirical data supporting the assumption that most tropical trees form AM associations for this region in the Guiana Shield and provide the first report of dual EM/AM colonization in
Dicymbe
species. Dual colonization of the
Dicymbe
species should be further explored to determine if this ability contributes to the establishment and maintenance of site dominance.
Abstract Background: Physical fitness is gaining in importance in all population groups, including elderly, but data are still scarce. The aim of this study was to report gender and age specific ...physical fitness levels in non-institutionalized Spanish elderly. Methods: A representative sample of 3136 elderly (≥65 y), 724 men and 2412 women, from 6 Regions of Spain: Madrid, Aragón, Castilla y León, Castilla-La Mancha, Extremadura and Canarias were assessed in the elderly EXERNET multi-center study between 2008 and 2009. The authors assessed static balance, muscular strength, flexibility, agility, walking speed and cardiorespiratory fitness using eight different fitness tests: one leg balance, chair stand, arm curl, chair sit-and-reach, back scratch, 8-foot up-and-go, 30-m walk, and 6 min walk tests. Results: The authors derived gender and age-specific normative values for physical fitness in the non-institutionalized Spanish elderly. The figures showed greater physical fitness in the elderly men than in women, except for the flexibility test, and a trend toward decreased physical fitness in both genders as their age increased. Conclusions: The normative values hereby provided will enable evaluation and correct interpretation of independent non-institutionalized Spanish elderly fitness status.
Abstract On the basis of several clinical and experimental researches, it is possible today to deepen the different mechanisms regarding kidney and liver relationships. However, the most studied ...field remains the renal function during liver disease. These alterations can be divided into: 1. Renal functional impairment is mainly considered due to hemodynamic derangement with a progressive decrease in peripheral vascular resistance (PVR) and an increase in cardiac output and rate, characteristic of hyperdynamic circulation, and outer cortex renal ischemia. Two principal forms of RFI characterize the hepatorenal syndrome (HRS) while in the first stage is based on the simple decrease in renal clearances with avid sodium retention. 2. Metabolic renal damage is principally due to abnormal serum levels of bile acids, bilirubin and perhaps toxic hepatic molecules which induce tubular dysfunction leading to RTA, of which type I, in the incomplete form, is the most common, varying between 30% and 50% of cases. It is mainly studied during cholestatic disease. 3. Organic renal impairment is principally based on immunological response to viral antigens and abnormal hepatic products which lead to the presence of immunocomplexes and cryoglobulins on the blood which tend to be deposited in the subendothelial and subepithelial glomerular areas, inducing complement activation, mesangial cell proliferation and monocyte-macrophage cell infiltration.
Pathogenic mechanisms of B‐cell lymphoproliferative disorders in chronic hepatitis C virus (HCV) infection are unclear. We studied t(14;18) translocation by polymerase chain reaction in peripheral ...blood mononuclear cells from 50 patients with HCV‐related liver disease (group A), 7 with mixed cryoglobulinemia syndrome (group B), 55 with HCV‐negative liver disease (group C), and 30 with HCV‐negative chronic rheumatic disorders or chronic infection by nonhepatotropic agents (group D). T(14;18) was significantly more frequent in group A (13/50 patients = 26 %) and group B (5/7 = 71.4%) patients than in group C (1/55 = 3.6%) and group D (1/30 = 3.3%) ones. Immunoblot analysis showed bcl‐2 over‐expression in all t(14;18)‐positive samples. In group A, 10/13 (77%) patients with t(14;18) and 13/37 (35%) without t(14;18) had serum cryoglobulins in the absence of mixed cryoglobulinemia symptoms (P < .05). These data indicate that t(14;18) and bcl‐2 over‐expression in lymphoid cells are frequent in chronic HCV infection and suggest that this event may contribute to the pathogenesis of HCV‐related lymphoproliferative disorders.
The underground oil-filled cable consists of a hollow copper conductor surrounded by oiled paper which acts as electrical insulation. The oil flows along the conductor and diffuses through it to the ...insulating paper. A lead sheath is used as the outer retaining wall. As the deterioration of this cover may cause a loss of insulation fluid, its detection is very important since this high voltage and power cable is used in cities even under sidewalks. The method of perfluorocarbon vapor tracers, based on the injection and subsequent detection of these volatile chemical substances in the vicinity of the cable, is one of the most promising methods, so far used in combination with gas chromatography and mass spectrometry. In this study, the possibility of detecting two different tracers,
C
6
F
12
and
C
7
F
14
, by means of resonant photoacoustic spectroscopy is studied. The beam from a tunable amplitude-modulated
CO
2
laser goes through an aluminum cell with quarter wave filters at both ends of an open resonator and an electret microphone in its center, attached to the walls. The calibration of the system for either substance diluted in chromatographic air showed a higher sensitivity for
C
7
F
14
, so the experiment was completed checking the behavior of this substance in samples prepared with ambient air in order to analyze the application of the system to field studies.
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