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1.
J Therm Biol ; 119: 103758, 2024 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-38070272

RESUMEN

L-menthol is a cyclic monoterpene derived from aromatic plants, which gives a cooling sensation upon application. With this in mind, L-menthol is beginning to be considered as a potential ergogenic aid for exercise and sporting competitions, particularly in hot environments, however female-specific research is lacking. The aim of this narrative review is to summarize available literature relating to topical application of L-menthol and provide commentary on avenues of consideration relating to future research developments of topical L-menthol in female athletes. From available studies in male participants, L-menthol topical application results in no endurance exercise performance improvements, however decreases in thermal sensation are observed. Mixed results are observed within strength performance parameters. Several genetic variations and single nucleotide polymorphisms have been identified in relation to sweat production, fluid loss and body mass changes - factors which may influence topical application of L-menthol. More specifically to female athletes, genetic variations relating to sweat responses and skin thickness, phases of the menstrual cycle, and body composition indices may affect the ergogenic effects of L-menthol topical application, via alterations in thermogenic responses, along with differing tissue distribution compared to their male counterparts. This narrative review concludes that further development of female athlete research and protocols for topical application of L-menthol is warranted due to physiological and genetic variations. Such developments would benefit research and practitioners alike with further personalized sport science strategies around phases of the menstrual cycle and body composition indices, with a view to optimize ergogenic effects of L-menthol.


Asunto(s)
Anestésicos , Sustancias para Mejorar el Rendimiento , Femenino , Humanos , Mentol/farmacología , Sustancias para Mejorar el Rendimiento/farmacología , Sudoración , Sensación Térmica , Anestésicos/farmacología , Extractos Vegetales/farmacología , Atletas
2.
J Strength Cond Res ; 38(7): e366-e372, 2024 Jul 01.
Artículo en Inglés | MEDLINE | ID: mdl-38595277

RESUMEN

ABSTRACT: Wilson, LJ and Curtis, C. Running event, age, and competitive level as predictors of dual-energy X-ray absorptiometry-derived body composition and bone health markers in female runners. J Strength Cond Res 38(7): e366-e372, 2024-The aim of this study was to assess the impact of running discipline, competitive level (COMP), and age on body composition measures in female athletes. A total of n = 51 female runners (age: 30.9 ± 5.7 years, stature: 166.7 ± 5.7 cm, and body mass (BM): 57.1 ± 8.2 kg) completed a full-body dual-energy x-ray absorptiometry (DXA) scan in a cross-sectional design. One-way ANOVA or Kruskal-Wallis was used to identify differences in DXA measures and independent variables. Stepwise regression determined the contribution of independent variables on DXA measures. Body fat percentage (BF%) and fat mass (FM) differed based on COMP (BF%: H (2) = 17.451; FM: H (2) = 17.406, both p ≤ 0.0001). Competitive level modestly predicted BF% and FM (BF%: R2adj = 0.316, F (1,50) = 22.660; FM: R2adj = 0.300, F (1,50) = 21.029, both p ≤ 0.0001). Bone mineral density (BMD) and BMD Z-score (BMD Z ) did not differ between age, running discipline, or COMP (age: BMD: F (2,50) = 2.825, BMD Z : F (2,50) = 2.215; running discipline: BMD: F (3,50) = 1.145, BMD Z : F (3,50) = 1.474; COMP: BMD: F (2,50) = 0.074, BMD Z : F (2,50) = 1.297, all p ≤ 0.05). Age and running discipline modestly predicted BMD and BMD Z (BMD: R2adj = 0.179, F (1,50) = 5.264; BMD Z : R2adj = 0.173, F (1,50) = 4.545, both p ≤ 0.05). These findings indicate COMP may be a predictor of BF% and FM. Age and running discipline appear predictors of bone health markers. Such findings may enable medical and sport science practitioners to tailor interventions relating to realization of training adaptations, performance, and health.


Asunto(s)
Absorciometría de Fotón , Composición Corporal , Densidad Ósea , Carrera , Humanos , Femenino , Carrera/fisiología , Adulto , Estudios Transversales , Composición Corporal/fisiología , Densidad Ósea/fisiología , Factores de Edad , Adulto Joven , Biomarcadores/sangre , Atletas , Conducta Competitiva/fisiología
3.
J Environ Manage ; 364: 121462, 2024 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-38878578

RESUMEN

The use of remote sensing for monitoring chlorophyll-a (chla) and modelling eutrophication has advanced over the last decades. Although the application of the technology has proven successful in ocean ecosystems, there is a need to monitor chla concentrations in large, nutrient-poor inland water bodies. The main objective of this study was to explore the utility of publicly available remotely sensed Sentinel-2 (S2) imagery to quantify chla concentrations in the nutrient-deficient Lake Malawi/Niassa/Nyasa (LMNN). A secondary objective was to compare the S2 derived chla with the Global Change Observation Mission-Climate (GCOM-C) chla product that provides uninterrupted data throughout the year. In situ chla data (n = 76) from upper, middle and lower sections of LMNN served as a reference to produce remote sensing-based quantification. The line-height approach method built on color index, was applied for chla concentrations below 0.25 mg/m3. Moderate Resolution Imaging Spectroradiometer 3-band Ocean Color (MODIS-OC3) - was adopted when chla concentration exceeded 0.35 mg/m3. The MODIS-OC3 algorithm had generic model coefficients that were calibrated for each in situ sample by using GCOM-C Level 3 chla product. A weighted sum of the two algorithms was applied for chla concentrations that fell between 0.25 and 0.35 mg/m3. The above methods were then applied to the S2 data to estimate chla at each pixel. S2 showed a promising accuracy in distinguishing chla levels (MSE = 0.18) although the chla range in the lake was relatively narrow, particularly using the locally calibrated coefficients of the OC3 algorithm. Chla distribution maps produced from the S2 data revealed limited spatial variation across the LMNN with higher concentrations identified in the coastal areas. S2-derived chla and GCOM-C chla comparison showed fairly good similarity between the two datasets (MSE = 0.205). Accepting this similarity, monthly chla dynamics of the lake was profiled using the temporally reliable GCOM-C data that showed oligotrophic conditions (1.7 mg/m3 to 3.2 mg/m3) in most parts of the lake throughout the year. The study's findings advance the potential for both remote sensing approaches to provide vital information at the required spatial and temporal resolution for evidence-based policymaking and proactive environmental management in an otherwise very data deficient region.


Asunto(s)
Clorofila A , Monitoreo del Ambiente , Lagos , Lagos/química , Monitoreo del Ambiente/métodos , Clorofila A/análisis , Tecnología de Sensores Remotos , Clorofila/análisis , Eutrofización , Malaui
4.
Chaos ; 33(8)2023 Aug 01.
Artículo en Inglés | MEDLINE | ID: mdl-38060776

RESUMEN

While the acquisition of time series has become more straightforward, developing dynamical models from time series is still a challenging and evolving problem domain. Within the last several years, to address this problem, there has been a merging of machine learning tools with what is called the dynamic-mode decomposition (DMD). This general approach has been shown to be an especially promising avenue for accurate model development. Building on this prior body of work, we develop a deep learning DMD based method, which makes use of the fundamental insight of Takens' embedding theorem to build an adaptive learning scheme that better approximates higher dimensional and chaotic dynamics. We call this method the Deep Learning Hankel DMD. We likewise explore how our method learns mappings, which tend, after successful training, to significantly change the mutual information between dimensions in the dynamics. This appears to be a key feature in enhancing DMD overall, and it should help provide further insight into developing other deep learning methods for time series analysis and model generation.

5.
J Strength Cond Res ; 37(10): e569-e580, 2023 Oct 01.
Artículo en Inglés | MEDLINE | ID: mdl-37235209

RESUMEN

ABSTRACT: Curtis, C, Mitchell, S, and Russell, M. Match-play demands and anthropometric characteristics of national and international women's, fifteen-a-side rugby union: a systematic scoping review. J Strength Cond Res 37(10): e569-e580, 2023-An increased professionalization within women's 15-a-side rugby union (R15s) has prompted greater sports science support and a need to better understand demands of the sport. Online database (PubMed, MEDLINE, and SPORTDiscus) searches were performed according to the PRISMA Scoping Review protocol. Studies were eligible if match-play demands or anthropometric characteristics of women's R15s players were investigated. After calibration exercises, the lead and senior authors independently quality assessed each study. A total of 1,068 studies were identified; 15 of which met the study criteria. The mean total match-play distance covered was 5,378 ± 626 m (forwards: 5,188 ± 667 m and backs: 5,604 ± 609 m), with first half values exceeding second half (2,922 ± 87 m vs. 2,876 ± 115 m). The mean relative distance (RD) (72.0 m·min -1 ) was greater than their male counterparts (64.2 m·min -1 -68.2 m·min -1 ). Backs were exposed to more severe collisions compared with forwards (6 ± 1 vs. 5 ± 4). Work:rest ratios ranged between 1.0:0.7-1.0:0.9. Regarding anthropometric characteristics, the mean lean and fat mass was reported as 51.9 ± 5.2 kg and 18.6 ± 4.6 kg, respectively. The mean body fat percentage was 24.7 ± 5.4%. The mean bone mineral density and bone mineral content was 1.27 ± 0.04 g·cm -2 and 3.07 ± 0.2 kg, respectively. This scoping review summarizes the current evidence base and key findings relating to the match-play demands and anthropometric characteristics that can be used in practice to inform player welfare and sport science support to women's R15s players at a national and international standard. Numerous gaps in our understanding of how best to develop and optimize performance, physical demands, and anthropometric characteristics of women's R15s players remain.


Asunto(s)
Rendimiento Atlético , Fútbol Americano , Carrera , Humanos , Masculino , Femenino , Rugby , Sistemas de Información Geográfica , Antropometría
6.
Disasters ; 39(4): 611-25, 2015 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-25752601

RESUMEN

The purpose of this study is to discover how coordination and communication between the government and service organisations responsible for the relief effort following Hurricane Katrina contributed to the poor outcomes for the communities impacted by the storm. Two hypotheses were tested in this study: communication was positively correlated with the degree of coordination immediately following Katrina; and miscommunication was negatively correlated with the degree of coordination after the storm. Quantitative content analysis of media reports was used to analyse the data and test the hypotheses. Both communication and miscommunication were found to be positively correlated with coordination. The results of this study suggest that increasing interorganisational communication and establishing clearly defined roles for organisations must be a high priority in revamping organisational protocol on disaster response if any new approach is to be successful.


Asunto(s)
Comunicación , Tormentas Ciclónicas , Desastres , Gobierno , Relaciones Interinstitucionales , Sistemas de Socorro/organización & administración , Humanos , Estados Unidos
7.
Sci Total Environ ; 927: 172180, 2024 Jun 01.
Artículo en Inglés | MEDLINE | ID: mdl-38580113

RESUMEN

River water quality is affected by various stressors (land-uses) operating at different hydrological spatial scales. Few studies have employed a multi-scaled analyses to differentiate effects of natural grasslands and woodlands, agriculture, impoundments, urban and mining stressors on headwater streams. Using a multi-scaled modeling approach, this study disentangled the distinct spatial signatures and mechanistic effects of specific stressors and topographic drivers on individual water quality parameters in tributaries of the Gwathle River Catchment in the Platinum Belt of South Africa. Water samples were collected on six occasions from 15 sites on three rivers over 12-months. Physio-chemical parameters as well as major anions, cations and metals were measured. Five key water quality parameters were identified using principal components analysis: sulfate, ammonium, copper, turbidity, and pH to characterise catchment water quality conditions. Using class-level composition (PLAND) and connectedness (COHESION) metrics together with topographic data, generalized linear mixed models were developed at multiple scales (sub-basin, cumulative catchment, riparian buffers) to identify the most parsimonious model with the dominant drivers of each water quality parameter. Ammonium concentrations were best explained by urban stress, Cu increased with mining and agriculture, turbidity increased with elevation heterogeneity, agriculture, urbanisation and fallow lands all at the sub-basin scale. River pH was positively predicted by slope heterogeneity, mining cover and impoundment connectivity at the catchment scale. Sulfate increased with mining and agriculture composition in the 100 m riparian buffer. Hierarchical cluster analysis of water quality and scale-dependent parsimonious drivers separated the river sites into three distinct groups distinguishing pristine, moderately impacted, and heavily mined sites. By demonstrating stressor- and scale-dependent water quality responses, this multi-scale nested modeling approach reveals the importance of developing adaptive, targeted management plans at hydrologically meaningful scales to sustain water quality amid intensifying land use.

8.
Nutrients ; 15(14)2023 Jul 19.
Artículo en Inglés | MEDLINE | ID: mdl-37513610

RESUMEN

To understand the energy balance of international female rugby sevens (R7s) players in applied environments, this study estimated the energy intakes (EI) and total daily estimated energy expenditures (TDEE) during a five-day training camp (TRAIN) and phase of competition preparation (COMP) of equal duration. Tri-axial accelerometer devices were worn throughout both scenarios to estimate TDEE, whereas EI was estimated via self-reported food diaries. Energy deficits of -47% (TDEETRAIN: 14.6 ± 1.6 MJ·day-1, EITRAIN: 7.7 ± 0.9 MJ·day-1, p ≤ 0.001, d = 5.1) and -50% (TDEECOMP: 15.5 ± 1.6 MJ·day-1, EICOMP: 7.7 ± 1.0 MJ·day-1, p ≤ 0.001, d = 5.7) were observed throughout TRAIN (n = 11; age: 25 ± 4 years, height: 170 ± 6 cm, weight: 71 ± 7 kg) and COMP (n = 8; age: 25 ± 3 years, height: 172 ± 5 cm, weight: 72 ± 6 kg), respectively. Carbohydrate intakes were below the lower range of sports nutrition recommendations in both TRAIN (-62%; 2.3 ± 0.3 g·kg-1 BM, p ≤ 0.001) and COMP (-60%; 2.4 ± 0.5 g·kg-1 BM, p ≤ 0.001). For protein (TRAIN: 1.7 ± 0.4 g·kg-1 BM, COMP: 1.5 ± 0.1 g·kg-1 BM), intakes met the lower range of recommendations. Fat intake exceeded recommendations of the percentage of total EI (COMP: 39 ± 5%). Accordingly, the dietary strategies of international female R7s players may warrant optimization, as carbohydrate and fat intakes were less than optimal when compared to current performance-based sports nutrition guidelines.


Asunto(s)
Ingestión de Energía , Rugby , Humanos , Femenino , Adulto Joven , Adulto , Dieta , Metabolismo Energético , Carbohidratos
9.
J Am Coll Health ; : 1-5, 2023 Feb 16.
Artículo en Inglés | MEDLINE | ID: mdl-36796083

RESUMEN

The purpose of the study was to investigate the moderating effect of discrimination experiences on the association between civic engagement and sleep in youth of color. Participants included 125 college students (Mage = 20.41, SD = 1.41, 22.6% cisgender male). Most of the sample (28%) identified as Hispanic, Latino, or Spanish origin; 26% identified as multi-racial/ethnicity; 23% identified as Asian; 19% identified as Black or African American; and 4% identified as Middle Eastern or North African. Youth self-reported their civic engagement (civic activism and civic efficacy), discriminatory experiences, and sleep duration during the week of the 2016 United States presidential inauguration (T1) and again approximately 100 days later (T2). Civic efficacy was associated with longer sleep duration. In contexts of discrimination, however, more civic activism and efficacy was associated with less sleep duration. In contexts of low discrimination, more civic efficacy was associated with longer sleep duration. Thus, civic engagement within supportive contexts may contribute to positive sleep among youth of color. Working toward dismantling racist systems may be one way to combat the racial/ethnic sleep disparities that underlie long-term health inequalities.

10.
Eur J Sport Sci ; 22(9): 1445-1451, 2022 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-34121611

RESUMEN

Eating disorders (ED), disordered eating (DE) and low energy availability (LEA) can be detrimental to health and performance. Previous studies have independently investigated the prevalence of ED, DE or LEA; however, few combined methods have identified risk within female athletes. The aim of this study was to identify the prevalence of ED, DE and LEA in UK-based female athletes and investigate whether associations exist between age, competition level and primary sport. The Female Athlete Screening Tool (FAST) and Low Energy Availability in Females Questionnaire (LEAF-Q) were used in a cross-sectional study design. A total of 112 responses eligible for analysis were received. A total of 16%, 44% and 53% of female athletes were at risk of ED (FAST: >94), DE and LEA, respectively. Competition level (recreational, competitive or professional athletes; fishers, p ≤ 0.05) influenced and was a predictor of FAST (R2 = 0.076, F(1,110) = 10.067, p ≤ 0.05, variance inflation value; VIF = 1.0) whereas age influenced (age: H(2) = 13.128, p ≤ 0.05), and was a predictor (R2 = 0.144, F(2,109) = 9.170, p ≤ 0.05, VIF = 1.0) of LEAF-Q. A positive correlation was observed between FAST and LEAF-Q scores (R = 0.496, p ≤ 0.05). Age and competition level may be predicting risk factors of ED/DE and LEA within female athletes; however, further research is required to support the findings of this present study.


Asunto(s)
Atletas , Trastornos de Alimentación y de la Ingestión de Alimentos , Estudios Transversales , Trastornos de Alimentación y de la Ingestión de Alimentos/epidemiología , Femenino , Humanos , Prevalencia , Encuestas y Cuestionarios , Reino Unido/epidemiología
11.
Phys Rev E ; 104(4-1): 044305, 2021 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-34781513

RESUMEN

Dynamic-mode decomposition (DMD) is a versatile framework for model-free analysis of time series that are generated by dynamical systems. We develop a DMD-based algorithm to investigate the formation of functional communities in networks of coupled, heterogeneous Kuramoto oscillators. In these functional communities, the oscillators in a network have similar dynamics. We consider two common random-graph models (Watts-Strogatz networks and Barabási-Albert networks) with different amounts of heterogeneities among the oscillators. In our computations, we find that membership in a functional community reflects the extent to which there is establishment and sustainment of locking between oscillators. We construct forest graphs that illustrate the complex ways in which the heterogeneous oscillators associate and disassociate with each other.

12.
Phys Rev E ; 103(1-1): 012201, 2021 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-33601499

RESUMEN

Dynamic-mode decomposition (DMD) is a well-established data-driven method of finding temporally evolving linear-mode decompositions of a nonlinear time series. Traditionally, this method presumes that all relevant dimensions are sampled through measurement. To address dynamical systems in which the data may be incomplete or represent only partial observation of a more complex system, we extend the DMD algorithm by including a Mori-Zwanzig decomposition to derive memory kernels that capture the averaged dynamics of the unresolved variables as projected onto the resolved dimensions. From this, we then derive what we call the memory-dependent dynamic mode decomposition (MDDMD). Through numerical examples, the MDDMD method is shown to produce reasonable approximations of the ensemble-averaged dynamics of the full system given a single time series measurement of the resolved variables.

13.
J Environ Health Sci Eng ; 19(1): 217-236, 2021 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-34150231

RESUMEN

PURPOSE: Per- and polyfluoroalkyl substances (PFAS) have been found to be widespread, extremely persistent and bioaccumulative with toxicity tendencies. Pre-synthesized nanocomposite-activated carbons, referred to, as physically activated maize tassel silver (PAMTAg) and chemically activated maize tassel silver (CAMTAg) were utilized in the present study. They were used for the removal of 10 PFAS from aqueous solutions. METHODS: The nanocomposite-activated carbons were characterized via scanning electron microscopy (SEM), Fourier transform infrared (FTIR) spectroscopy, Brunauer Emmett Teller (BET) and other techniques. Batch equilibrium experiments were conducted in order to investigate the effects of solution pH, adsorbent dosage, initial PFAS concentration and temperature on the removal of PFAS using PAMTAg and CAMTAg. Langmuir and Freundlich adsorption isotherm models were used to analyse the equilibrium data obtained. RESULTS: Maximum adsorption capacities of 454.1 mg/g (0.91 mmol/g) and 321.2 mg/g (0.78 mmol/g) were recorded for perfluorooctanesulfonate (PFOS) and perfluorooctanoate (PFOA), respectively using CAMTAg. The values recorded for the Gibbs' free energy (ΔG°) for the adsorption of PFOS and PFOA onto PAMTAg and CAMTAg were negative; PFOS (-9.61, -9.99 and - 10.39), PFOA (-8.77, -9.76 and - 10.21) using PAMTAg; and PFOS (-13.70, -12.70 and - 12.37), PFOA (-12.86, -12.21 and - 11.17) using CAMTAg. Therefore, the adsorption processes were spontaneous and feasible. The values recorded for enthalpy (ΔH°) (kJ/mol) for the adsorption of PFOS (-26.15) and PFOA (-35.86) onto CAMTAg were negative, indicating that the adsorption mechanism is exothermic in nature. Positive values were recorded for ΔH° for the adsorption of PFOS (2.32) and PFOA (12.69) onto PAMTAg, indicative of an endothermic adsorption mechanism. Positive entropy (ΔS°) values (0.04 and 0.07) were recorded for PFOS and PFOA using PAMTAg; whereas negative values (-0.04 and - 0.08) were recorded for ΔS° using CAMTAg. A positive ΔS° indicates an increase in randomness of the adsorbate at the solid-solution interface and the reverse is the case for a negative ΔS°. CONCLUSION: The interplay of electrostatic attraction and hydrophobic interactions enabled the removal of PFAS using PAMTAg and CAMTAg. Findings suggest that PAMTAg and CAMTAg are effective for the removal of PFAS from aqueous media and are good alternatives to commercially available activated carbons. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s40201-020-00597-3.

14.
Int J Sports Physiol Perform ; 16(9): 1234-1241, 2021 09 01.
Artículo en Inglés | MEDLINE | ID: mdl-33626507

RESUMEN

Rugby union (RU) is a field-based team sport with a large number of high-intensity actions such as sprinting, change of direction, tackling, scrummaging, rucking, and mauling. Competitive success in female RU has previously been related to anthropometric and physical characteristics, and with the recent introduction of professionalism in female rugby, characterizing such physical attributes may provide insight into selection and training processes. PURPOSE: To identify anthropometric and physical characteristics of competitive female RU players and differences between playing positions. METHODS: Twenty-two players were recruited from the top tier of female RU in the United Kingdom during the 2018-2019 Premiership season. Players were split into forwards and backs and underwent body composition testing via dual-X-ray absorptiometry and physical characteristic tests (10- and 20-m speed, 1-repetition-maximum bench press and squat, countermovement jump, drop jump, isometric midthigh pull, and 1200-m shuttle). RESULTS: Moderate to large significant differences between playing positions in both anthropometric and physical characteristics were found (P < .01). Forwards displayed greater body mass (P = .03), fat mass (P = .01), and absolute upper-body strength (P = .03), whereas backs demonstrated superior countermovement jump height (P = .01), drop jump height (P = .01), greater reactive strength (P = .03), and speed (P = .03). CONCLUSION: These findings provide practitioners with a greater understanding of anthropometric and physical characteristics of professional female RU players.


Asunto(s)
Rendimiento Atlético , Fútbol Americano , Antropometría , Estatura , Femenino , Humanos , Fuerza Muscular , Aptitud Física , Rugby
15.
Mil Med ; 175(5): 367-9, 2010 May.
Artículo en Inglés | MEDLINE | ID: mdl-20486511

RESUMEN

Lyme disease is a tick-transmitted disease caused by the spirochete Borrelia burgdorferi. Cases have been reported across the United States, Canada, and Europe. Additional cases have been described in other parts of the world including Japan, Mexico, and Turkey. We report an unexpected case of Lyme disease from Iraq.


Asunto(s)
Eritema Crónico Migrans/diagnóstico , Guerra de Irak 2003-2011 , Adulto , Antibacterianos/uso terapéutico , Borrelia burgdorferi , Doxiciclina/uso terapéutico , Eritema Crónico Migrans/tratamiento farmacológico , Eritema Crónico Migrans/microbiología , Humanos , Irak , Enfermedad de Lyme/diagnóstico , Enfermedad de Lyme/tratamiento farmacológico , Enfermedad de Lyme/microbiología , Masculino , Medicina Militar , Personal Militar , Estados Unidos
16.
Sci Total Environ ; 737: 139642, 2020 Oct 01.
Artículo en Inglés | MEDLINE | ID: mdl-32546308

RESUMEN

Naturally accumulating archives, such as lake sediments and wetland peats, in remote areas may be used to identify the scale and rates of atmospherically deposited pollutant inputs to natural ecosystems. Co-located lake sediment and wetland cores were collected from Letseng-la Letsie, a remote lake in the Maloti Mountains of southern Lesotho. The cores were radiometrically dated and analysed for a suite of contaminants including trace metals and metalloids (Hg, Pb, Cu, Ni, Zn, As), fly-ash particles, stable nitrogen isotopes, polycyclic aromatic hydrocarbons (PAHs) and persistent organic pollutants such as polychlorinated biphenyls (PCBs), polybrominated flame retardants (PBDEs) and hexachlorobenzene (HCB). While most trace metals showed no recent enrichment, mercury, fly-ash particles, high molecular weight PAHs and total PCBs showed low but increasing levels of contamination since c.1970, likely the result of long-range transport from coal combustion and other industrial sources in the Highveld region of South Africa. However, back-trajectory analysis revealed that atmospheric transport from this region to southern Lesotho is infrequent and the scale of contamination is low. To our knowledge, these data represent the first palaeolimnological records and the first trace contaminant data for Lesotho, and one of the first multi-pollutant historical records for southern Africa. They therefore provide a baseline for future regional assessments in the context of continued coal combustion in South Africa through to the mid-21st century.

17.
Malar J ; 8 Suppl 2: S2, 2009 Nov 16.
Artículo en Inglés | MEDLINE | ID: mdl-19917072

RESUMEN

Research on sterile mosquito technology from 1955 to the 1980s provided a substantial body of knowledge on propagation and release of sterile mosquitoes. Radiation sterilisation and chemosterilisation have been used effectively to induce dominant lethality and thereby sterilise important mosquito vectors in the laboratory. Experimental releases of chemosterilised males provided complete control of Anopheles albimanus in a small breeding population (14-15 sq km) in El Salvador. Releases of radiation sterilised males failed to control either Aedes aegypti or Anopheles quadrimaculatus in the USA. Releases of radiation-sterilised and chemosterilised male Culex quinquefasciatus in the USA and India were successful in some instances. Development of genetic sexing systems for Anopheles and improved physical separation methods for Culex have made it possible to rear and release males almost exclusively (> 99%) minimizing the release of potential vectors, the females. Factors that affected efficacy in some field programmes included reduction of competitiveness by radiation, immigration of fertilized females from outside the release zones, and inability of laboratory-bred males to perform in the wild. Despite significant progress, institutional commitments to carry the process further were generally lacking in the late 1970s and until recently. Now, with renewed interest and support for further assessment of this technology, this paper summarizes the current knowledge base, prioritizes some areas of investigation, and challenges scientists and administrators to maintain an awareness of progress, remain realistic about the interpretation of new findings, and make decisions about the sterile insect technique on the basis of informed scientific documentation. Areas recommended for priority research status include the establishment of genetic sexing mechanisms that can be transferred to other mosquito species, re-examination of radiation sterilisation, aerial release technology and mass rearing.


Asunto(s)
Anopheles/efectos de la radiación , Control de Mosquitos/historia , Animales , Anopheles/crecimiento & desarrollo , Esterilizantes Químicos , Femenino , Fertilidad/efectos de la radiación , Historia del Siglo XX , Masculino , Control de Mosquitos/métodos , Dinámica Poblacional , Conducta Sexual Animal/efectos de los fármacos
18.
Phys Rev E ; 99(6-1): 062215, 2019 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-31330623

RESUMEN

We use the dynamic mode decomposition (DMD) methodology to study weakly turbulent flows in two-dimensional Bose-Einstein condensates modeled by a Gross-Pitaevskii equation subject to band-limited stochastic forcing. The forcing is balanced by the removal of energy at both ends of the energy spectrum through phenomenological hypoviscosity and hyperviscosity terms. Using different combinations of these parameters, we simulate three different regimes corresponding to weak-wave turbulence, and high- and low-frequency saturation. By extracting and ranking the primary DMD modes carrying the bulk of the energy, we are able to characterize the different regimes. In particular, the proposed DMD mode projection is able to seamlessly extract the vortices present in the condensate. This is achieved despite the fact that we do not use any phase information of the condensate as it is usually not directly available in realistic atomic BEC scenarios. Being model independent, this DMD methodology should be portable to other models and experiments involving complex flows. The DMD implementation could be used to elucidate different types of turbulent regimes as well as identifying and pinpointing the existence of delicate and hidden coherent structures within complex flows.

19.
Malar J ; 7: 38, 2008 Feb 28.
Artículo en Inglés | MEDLINE | ID: mdl-18307802

RESUMEN

BACKGROUND: Long-lasting insecticidal nets (LLINs) are advocated by WHO for protection against malaria. Of the three brands of LLINs currently approved by WHO, Olyset(R) is the only one currently granted full recommendation. With this type of LLIN, the insecticide (permethrin) is incorporated into the polyethylene fibre during manufacture and diffuses from the core to the surface, thereby maintaining surface concentrations. It has not been determined for how long Olyset nets remain protective against mosquitoes in household use. METHODS: Examples of Olyset nets, which had been in use in Tanzanian villages for seven years, were tested in experimental huts against naturally entering Anopheles gambiae and Anopheles funestus mosquitoes. Performance was compared with new Olyset nets, conventionally treated ITNs (either newly treated with alphacypermethrin or taken from local villages after 1.5 years of use) and untreated nets. All nets were artificially holed except for the seven-year Olyset nets, which had developed holes during prolonged domestic use. RESULTS: Anopheles funestus and An. gambiae in NE Tanzania are susceptible to pyrethroids. The new Olyset nets caused high mortality against An. funestus (73.9%) and An. gambiae (62.7%) in experimental huts. The seven-year Olyset nets caused 58.9% mortality against An. funestus and 40.0% mortality against An. gambiae. The freshly treated alphacypermethrin nets also caused high mortality against An. funestus (70.6%) and An. gambiae (72.0%); this decreased to 58.4% and 69.6% respectively after 1.5 years of use. The new Olyset nets inhibited blood-feeding by 40-50%. The 7 year Olyset nets showed no feeding inhibition over that shown by the untreated nets. The alphacypermethrin treated nets failed to inhibit blood-feeding after 1.5 years of use. However iHhhdn laboratory tunnel tests samples of all types of treated net including the 7 year Olyset inhibited blood-feeding by more than 95%. CONCLUSION: After seven years of use Olyset nets were still strongly insecticidal. Mosquito mortality decreased by only 20-35% over this period. However, Olyset would not provide personal protection after seven years unless it was in good condition and all holes fully repaired.


Asunto(s)
Anopheles , Ropa de Cama y Ropa Blanca/normas , Mordeduras y Picaduras de Insectos/prevención & control , Insectos Vectores , Malaria/prevención & control , Control de Mosquitos/métodos , Animales , Anopheles/efectos de los fármacos , Bioensayo , Humanos , Insectos Vectores/efectos de los fármacos , Insecticidas/farmacología , Piretrinas/farmacología , Tanzanía , Factores de Tiempo
20.
Mil Med ; 173(5): 507-8, 2008 May.
Artículo en Inglés | MEDLINE | ID: mdl-18543574

RESUMEN

A patient with no significant medical history presented with myalgias, lower extremity weakness, and facial diplegia. Upon review of systems, the patient denied any other problems. Physical examination results were remarkable for weakness in the right leg and bilateral facial diplegia. Radiological and laboratory studies were unremarkable. Lumbar puncture revealed albuminocytological dissociation. The combined history, physical examination, and lumbar puncture results established a presumptive diagnosis of Guillain-Barré syndrome. The patient began a 5-day course of intravenous immunoglobulin therapy. At the end of the 5-day course, the patient had recovered 85% of her facial muscle function and experienced complete relief of her myalgias. Upon discharge, the patient was referred to physical therapy for improvement of her facial muscle impairment.


Asunto(s)
Inmunoglobulinas/uso terapéutico , Síndrome de Miller Fisher/diagnóstico , Enfermedad Aguda , Parálisis Facial/diagnóstico , Parálisis Facial/etiología , Femenino , Humanos , Inmunoglobulinas/administración & dosificación , Factores Inmunológicos/administración & dosificación , Factores Inmunológicos/uso terapéutico , Persona de Mediana Edad , Síndrome de Miller Fisher/tratamiento farmacológico , Enfermedades Musculares/diagnóstico , Enfermedades Musculares/etiología
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