Separating Mangrove Species and Conditions Using Laboratory Hyperspectral Data: A Case Study of a Degraded Mangrove Forest of the Mexican Pacific

Given the scale and rate of mangrove loss globally, it is increasingly important to map and monitor mangrove forest health in a timely fashion. This study aims to identify the conditions of mangroves in a coastal lagoon south of the city of Mazatlán, Mexico, using proximal hyperspectral remote sensing techniques. The dominant mangrove species in this area includes the red (Rhizophora mangle), the black (Avicennia germinans) and the white (Laguncularia racemosa) mangrove. Moreover, large patches of poor condition black and red mangrove and healthy dwarf black mangrove are commonly found. Mangrove leaves were collected from this forest representing all of the aforementioned species and conditions. The leaves were then transported to a laboratory for spectral measurements using an ASD FieldSpec® 3 JR spectroradiometer (Analytical Spectral Devices, Inc., USA). R2 plot, principal components analysis and stepwise discriminant analyses were then used to select wavebands deemed most appropriate for further mangrove classification. Specifically, the wavebands at 520, 560, 650, 710, 760, 2100 and 2230 nm were selected, which correspond to chlorophyll absorption, red edge, starch, cellulose, nitrogen and protein regions of the spectrum. The classification and validation indicate that these wavebands are capable of identifying mangrove species and mangrove conditions common to this degraded forest with an overall accuracy and Khat coefficient higher than 90% and 0.9, respectively. Although lower in accuracy, the classifications of the stressed (poor condition and dwarf) mangroves were found to be satisfactory with accuracies higher than 80%. The results of this study indicate that it could be possible to apply laboratory hyperspectral data for classifying mangroves, not only at the species level, but also according to their health conditions

Examining the influence of seasonality, condition, and species composition on mangrove leaf pigment contents and laboratory based spectroscopy data

The purpose of this investigation was to determine the seasonal relationships (dry vs. rainy) between reflectance (400-1000 nm) and leaf pigment contents (chlorophyll-a (chl-a), chlorophyll-b (chl-b), total carotenoids (tcar), chlorophyll a/b ratio) in three mangrove species (Avicennia germinans (A. germinans), Laguncularia racemosa (L. racemosa), and Rhizophora mangle (R. mangle)) according to their condition (stressed vs. healthy). Based on a sample of 360 leaves taken from a semi-arid forest of the Mexican Pacific, it was determined that during the dry season, the stressed A. germinans and R. mangle show the highest maximum correlations at the green (550 nm) and red-edge (710 nm) wavelengths (r = 0.8 and 0.9, respectively) for both chl-a and chl-b and that much lower values (r = 0.7 and 0.8, respectively) were recorded during the rainy season. Moreover, it was found that the tcar correlation pattern across the electromagnetic spectrum was quite different from that of the chl-a, the chl-b, and chl a/b ratio but that their maximum correlations were also located at the same two wavelength ranges for both seasons. The stressed L. racemosa was the only sample to exhibit minimal correlation with chl-a and chl-b for either season. In addition, the healthy A. germinans and R. mangle depicted similar patterns of chl-a and chl-b, but the tcar varied depending on the species. The healthy L. racemosa recorded higher correlations with chl-b and tcar at the green and red-edge wavelengths during the dry season, and higher correlation with chl-a during the rainy season. Finally, the vegetation index Red Edge Inflection Point Index (REIP) was found to be the optimal index for chl-a estimation for both stressed and healthy classes. For chl-b, both the REIP and the Vogelmann Red Edge Index (Vog1) index were found to be best at prediction. Based on the results of this investigation, it is suggested that caution be taken as mangrove leaf pigment contents from spectroscopy data have been shown to be sensitive to seasonality, species, and condition. The authors suggest potential reasons for the observed variability in the reflectance and pigment contents relationships

The association between the weight of schoolbags and low back pain among schoolchildren: A systematic review, meta‐analysis and individual patient data meta‐analysis

[EN] Background The objective of this study was to determine whether carrying a heavy schoolbag is associated to a higher prevalence of low back pain (LBP). Methods A systematic review and meta-analysis was conducted (PROSPERO, CRD42018077839). Observational studies analysing the relationship between schoolbag weight and LBP, were searched for in 20 electronic databases and 12 specialized journals until February 28th, 2019, without date or language restrictions. All studies which included ≥ 50 subjects aged 9 to 16, were reviewed. Methodological quality was assessed by two reviewers separately, using validated tools. A meta-analysis and an individual patient data (IPD) meta-analysis were conducted to examine the relationship between schoolbag weight and LBP. Certainty of evidence was assessed using an adapted GRADE methodology. Results 5,524 citations were screened, 21 studies (18,296 subjects) were reviewed and 11 studies (9,188 subjects) were included in the meta-analysis. The IPD meta-analysis included 9,188 subjects from seven studies. Among the 21 studies reviewed, the mean score for methodological quality was 78.3 of 100. Only one study suggested an association between heavier schoolbags and LBP. Neither the meta-analysis nor the IPD meta-analysis found an association between carrying schoolbags weighing > 10% of bodyweight, and LBP. No differences based on age, gender or sport activity were found. Discussion Available evidence does not support that schoolbags weighing > 10% of bodyweight are associated with a higher prevalence of LBP among schoolchildren aged 9–16. The certainty of evidence is low. Further research is required on the relationship between schoolbag weight and LBP. Significance This systematic review, with a meta-analysis and an IPD meta-analysis, failed to find a link between schoolbags weighing ≥ 10% of body weight and LBP among schoolchildren aged 9 to 16. Further longitudinal studies, with large samples, long follow-up periods, and rigorous methods taking into account duration of carry and the physical capacity of each subject, are required in this field.S

The Efficacy and Effectiveness of Education for Preventing and Treating Non-Specific Low Back Pain in the Hispanic Cultural Setting: A Systematic Review

A systematic review was conducted to assess the efficacy and effectiveness of education programs to prevent and treat low back pain (LBP) in the Hispanic cultural setting. Electronic and manual searches identified 1148 unique references. Nine randomized clinical trials (RCTs) were included in this review. Methodological quality assessment and data extraction followed the recommendations from the Cochrane Back Pain Review Group. Education programs which were assessed focused on active management (3 studies), postural hygiene (7), exercise (4) and pain neurophysiology (1). Comparators were no intervention, usual care, exercise, other types of education, and different combinations of these procedures. Five RCTs had a low risk of bias. Results show that: (a) education programs in the school setting can transmit potentially useful knowledge for LBP prevention and (b) education programs for patients with LBP improve the outcomes of usual care, especially in terms of disability. Education on pain neurophysiology improves the results of education on exercise, and education on active management is more effective than “sham” education and education on postural hygiene. Future studies should assess the comparative or summatory effects of education on exercise, education on pain neurophysiology and education on active management, as well as explore their efficiency

Relación entre hábitos de vida y calificaciones escolares en adolescentes

Diversos estudios han mostrado que el rendimiento académico de los adolescentes está estrechamente vinculado al consumo de alcohol y tabaco y a las horas que pasan viendo televisión. El objetivo del presente estudio es determinar la relación del tiempo viendo televisión, el tabaquismo y el consumo de alcohol con las calificaciones escolares de adolescentes de Mallorca, España. Métodos: Se registraron datos sobre la práctica de deportes, el consumo de alcohol y tabaco, el tiempo que pasan ante el televisor y el número de asignaturas suspendidas en el último curso entre 7.361 escolares de 13 a 15 años de edad. El nivel socioeconómico de la familia se determinó a partir de los datos proporcionados por los padres de los adolescentes. Mediante un análisis multivariante se identificaron las variables asociadas al hecho de presentar un mayor riesgo de suspender. Resultados: Las variables significativamente asociadas a problemas académicos fueron: tabaco (odds ratio [OR] = 2,64: intervalo de confianza [IC] del 95%: 2,17-3,20); alcohol (OR = 1,58; IC del 95%: 1,34-1,87); ver más de 2 h de televisión por día (OR = 1,42; IC del 95%: 1,19-1,69); proceder del nivel socioeconómico más bajo (OR = 5,72; IC del 95%: 3,74-8,73) y tener más edad (OR = 1,23; IC del 95%: 1,16-1,31). Las variables que se revelaron como positivamente asociadas a un buen rendimiento académico fueron: practicar deportes a nivel competitivo (OR = 0,648; IC del 95%: 0,594-0,787); practicar deportes más de 2 veces por semana (OR = 0,820; IC del 95%: 0,712-0,945), y ser mujer (OR = 0,422; IC del 95%: 0,373-0,477). Conclusiones: Entre los adolescentes españoles, fumar, beber alcohol, tener más años, ser varón, ver televisión más de 2 h al día y proceder de un nivel socioeconómico más bajo están estrechamente asociados al fracaso escolar. Practicar deporte más de 2 veces por semana está asociado a un mejor rendimiento académico

The Efficacy and Effectiveness of Education for Preventing and Treating Non-Specific Low Back Pain in the Hispanic Cultural Setting: A Systematic Review

[EN] A systematic review was conducted to assess the efficacy and effectiveness of education programs to prevent and treat low back pain (LBP) in the Hispanic cultural setting. Electronic and manual searches identified 1148 unique references. Nine randomized clinical trials (RCTs) were included in this review. Methodological quality assessment and data extraction followed the recommendations from the Cochrane Back Pain Review Group. Education programs which were assessed focused on active management (3 studies), postural hygiene (7), exercise (4) and pain neurophysiology (1). Comparators were no intervention, usual care, exercise, other types of education, and different combinations of these procedures. Five RCTs had a low risk of bias. Results show that: (a) education programs in the school setting can transmit potentially useful knowledge for LBP prevention and (b) education programs for patients with LBP improve the outcomes of usual care, especially in terms of disability. Education on pain neurophysiology improves the results of education on exercise, and education on active management is more effective than “sham” education and education on postural hygiene. Future studies should assess the comparative or summatory effects of education on exercise, education on pain neurophysiology and education on active management, as well as explore their efficiency.S

Acupuncture and radioactive pathways of hypodermically injected technetium-99m

To the editor: In our opinion, some of the interpretations of Scott and Vernejoul and associates are not supported by the data contained in a recently published study by our group

Prevalence and factors associated with a higher risk of neck and back pain among permanent wheelchair users: a cross-sectional study

[EN] Study design: Cross-sectional study. Objectives: To determine the prevalence of, and factors associated with, spinal pain among wheelchair users. Setting: Four Spanish hospitals specialized in providing care for wheelchair users. Methods: Persons who had used a wheelchair for a median (IRQ) of 10 (5;19) years, 27% of them due to reasons other than spinal cord injury, were recruited consecutively (n = 750). Data on 43 demographic, psychosocial, ergonomic, and clinical variables were collected, and analyzed. Main outcome measures were: Point prevalence of neck (NP), thoracic (TP), low back pain (LBP), and pain at any spinal level (PASL); and factors associated with them. Results: Point prevalence was 56% for NP, 54% for TP, 45% for LBP, and 76% for PSAL. PASL was associated with a lower quality of life (OR (95% CI) 0.91 (0.86; 0.97)). Multivariable regression models showed that the main factors associated with significant pain (≥1.5 VAS points) were: (a) For NP: Cervical spinal injury and wheelchair seat cushion thickness, (b) For TP: Thoracic spinal injury and sagittal index, (c) For LBP: Thoracic or lumbar spinal injury, with some sensitivity remaining, (d) For PASL: Being female, living alone, and using a non-power wheelchair. Discrimination (AUC) of these models ranged between 0.638 and 0.818. p-values in the Hosmer-Lemeshow test ranged between 0.420 and 0.701. Conclusions: Prevalence of spinal pain among wheelchair users is high. It is associated with a lower quality of life. Future studies should assess whether using a power wheelchair affects PASL, and if the thickness of seat cushion affects NP. Sponsorship: Spanish Back Pain Research NetworkS

Analytical Modeling of Distributed Location Based Access for Vehicular Ad Hoc Networks

One of the key ingredients of Intelligent Transportation Systems (ITS) is delivery of broadcast status messages among vehicles for safety purposes. This requires an efficient Medium Access Control (MAC) that provides low average delay and high reliability. To this end, Carrier Sense Multiple Access (CSMA) has been commonly proposed for Vehicle Ad Hoc Networks (VANETs). Nevertheless, the hidden-node problem can jeopardize the reliability of CSMA, whereas the latency when accessing the channel can be unbounded. To overcome these limitations, resource allocation based on the geo-location of the vehicles can be applied in VANETs. For example, a distributed location based access (DLOC) algorithm has been proposed such that vehicles access orthogonal resource blocks based on their position, aiming at maximizing the distance of co-channel transmitters. In this paper we propose a stochastic geometry approach to analyze DLOC taking into account path loss and fading as well as the random location of transmitting vehicles. Analytical results include the average interference, average binary rate and capture probability, i.e. probability of successful message transmission. It is shown that increasing the number of RBs increases reliability but there is a trade off between reliability and average BR.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

The prognostic value of catastrophizing for predicting the clinical evolution of low back pain patients: a study in routine clinical practice within the Spanish National Health Service

Francisco Javier Cano García es miembro de la Spanish Back Pain Research Network (Red Española de Investigadores en Dolencias de la Espalda (REIDE) y coautor del artículoBackground context Experimental studies suggest that catastrophizing may worsen the prognosis of low back pain (LBP) and LBP-related disability and increase the risk of chronicity. Purpose To assess the prognostic value of baseline catastrophizing for predicting the clinical evolution of LBP patients in routine clinical practice and the association between the evolution of pain and catastrophizing. Study design/setting Prospective study in routine clinical practice of the Spanish National Health Service. Patient sample One thousand four hundred twenty-two acute and chronic adult LBP patients treated in primary and hospital care. Outcome measures Pain, disability, and catastrophizing measured through validated instruments. Methods Patients were managed according to routine clinical practice. Outcome measures were assessed at baseline and 3 months later. Logistic regression models were developed to estimate the association between baseline catastrophizing score and the improvement of LBP and disability, adjusting for baseline LBP and leg pain (LP) severity, disability, duration of the pain episode, workers' compensation coverage, radiological findings, failed back surgery, and diagnostic procedures and treatments undertaken throughout the study. Another model was developed to estimate the association between the evolution of LBP and the change in catastrophizing, adjusting for the same possible confounders plus the evolution of LP and disability. Models were repeated excluding the treatments undergone after the baseline assessment. Results Regression models showed that the degree of baseline catastrophizing does not predict the evolution of LBP and disability. Conversely, as the degree of pain improvement increases, so does the odds ratio for improvement in catastrophizing, ranging from three (95% confidence interval [95% CI], 2.00–4.50; p<.001) for improvements in pain between 1.1 and 4 visual analog scale (VAS) points, to 7.3 (95% CI, 3.49–15.36; p<.001) for improvements in pain more than 6.1 VAS points. Similar results were obtained when treatments were excluded from the models. Conclusions In routine practice, assessing the baseline score for catastrophizing does not help clinicians to predict the evolution of LBP and disability at 3 months.Spanish Ministry of Health’s Agency for QualityKovacs Foundatio