Using dynamic modelling to enhance the assessment of the beef water footprint.

Current water footprint assessment methods make a meaningful assessment of livestock water consumption difficult as they are mainly static, thus poorly adaptable to understanding future water consumption and requirements. They lack the integration of fundamental ruminant nutrition and growth equations within a dynamic context that accounts for short- and long-term behaviour and time delays associated with economically significant beef-producing areas. The current study utilised the System Dynamics methodology to conceptualise a water footprint for beef cattle within a dynamic and mechanistic modelling framework. The problem of assessing the water footprint of beef cattle was articulated, and a dynamic hypothesis was formed to represent the Texas livestock water use system as the initial step in developing the Dynamic Beef Water Footprint model (DWFB). The dynamic hypothesis development resulted in three causal loop diagrams (CLD): cattle population, growth and nutrition, and the livestock water footprint, that captured the daily water footprint of beef (WFB). Simulations and sensitivity analysis from the hypothesised CLD structures indicated that the framework was able to capture the dynamic behaviour of the WFB system. These behaviours included key reinforcing and balancing feedback processes that drive the WFB. It is extremely difficult to identify policy interventions (i.e., management strategies) for complex systems, like the U.S. beef cattle system, because there are many actors (i.e., cow-calf, stocker, feedlot) and interrelated variables that have delayed effects within and across the supply chain. Identification and understanding of feedback processes driving water use over time will help to overcome policy resistance for more sustainable beef production. Thus, the causal loops identified in the current study provide a system-level insight for the drivers of the WFB within and across each major segment of the beef supply chain to address freshwater concerns more adequately. Further, the nutrient scenarios and sensitivity analysis revealed that the high versus low nutrient composition of pasture, hay, and concentrates resulted in a significant difference in the WFB (2 669 L/kg boneless beef, P < 0.05). The WFB was sensitive to changes in nutrient composition and specific water demand (m3/t) for each production phase, not only phases with high levels of concentrate feed use. As models evolve, there is potential for the DWFB to integrate precision livestock data, further improving quantification of the WFB, precision water-efficient strategies, and selection of water-efficient livestock.

Chronic effects of simultaneous electromyostimulation and vibration on leg blood flow in spinal cord injury.

STUDY DESIGN: Randomized two-group parallel. OBJECTIVES: The objective of this study was to analyze the adaptations on the popliteal artery (mean blood velocity (MBV), peak blood velocity (PBV), arterial resting diameter (RD) and blood flow (BF)) induced by 12 weeks of simultaneous application of whole-body vibration and electromyostimulation (WBV+ES) in patients with spinal cord injury (SCI). Secondarily, the musculoskeletal effects of this therapy on the gastrocnemius muscle thickness (MT) and femoral neck bone mineral density (BMD) were analyzed. SETTING: Valladolid, Spain. METHODS: Seventeen SCI patients (American Spinal Injury Association (ASIA) A or B) were randomly assigned to the experimental group (EG=9) or the control group (CG=8). Each subject was assessed in four different occasions: at baseline, after 6 weeks (Post-6) and 12 weeks of the treatment (Post-12) and 8 weeks after the end of the treatment (Post-20). Subjects in the EG performed 30 10-min sessions of WBV+ES during 12 weeks. RESULTS: In the EG, RD increased compared with the baseline value at Post-6 (9.5%, P<0.01), Post-12 (19.0%, P<0.001) and Post-20 (16.7%, P<0.001). Similarly, in the EG, BF increased compared with the baseline value and with CG only at Post-12 ((33.9%, P<0.01) and (72.5%, P<0.05), respectively). Similarly, WBV+ES increased the MT of the gastrocnemius. BMD of both hips remained invariable during the study. CG showed no change at any point. CONCLUSIONS: WBV+ES improved popliteal artery BF, RD and MT after 12 weeks in SCI patients. This increase in RD remained above baseline after 8 weeks. The combination of WBV and ES could be considered a promising alternative to reverse the musculoskeletal atrophy and improve peripheral vascular properties in SCI patients.

Acute effects of simultaneous electromyostimulation and vibration on leg blood flow in spinal cord injury.

STUDY DESIGN: Randomized crossover. OBJECTIVES: To analyze the acute effects of isolated and simultaneous application of whole-body vibration (WBV) and electromyostimulation (ES) on popliteal artery blood velocity (BV) and skin temperature (ST) of the calf in subjects with spinal cord injury (SCI). SETTING: Valladolid, Spain. METHODS: Ten subjects with SCI were assessed in five different sessions. After a familiarization session, four interventions were applied in random order; WBV, ES, simultaneous WBV and ES (WBV+ES), and 30 s of WBV followed by 30 s of ES (WBV30/ES30). Each intervention consisted of 10 sets × 1 min ON+1 min OFF. Subjects were seated on their own wheelchairs with their feet on the vibration platform (10 Hz, 5 mm peak-to-peak), and ES was applied on the gastrocnemius muscle of both legs (8 Hz, 400 µs). RESULTS: The simultaneous application (WBV+ES) produced the greatest increase in mean BV (MBV; 36% and 42%, respectively) and peak BV (PBV; 30% and 36%, respectively) during the intervention. This intervention produced the greatest mean increases in MBV (21%) and PBV (19%) during the recovery period. Last, this intervention produced the highest increase in ST during the intervention (2.1 °C). CONCLUSION: The simultaneous application of WBV+ES seems to produce a greater increase in MBV and PBV of the popliteal artery and ST of the calf than the isolated (WBV or ES) or consecutive application of both stimuli (WBV30/ES30). This study provides an efficient therapeutic methodology to improve peripheral arterial properties, which is pivotal in SCI patient's rehabilitation.

Tratamiento del dolor de hombro mediante vibración puntual en lesionados medulares / Shoulder pain treatment with punctual vibration in spinal cord injury patients

Objetivo: Analizar los efectos inmediatos agudos de cuatro tratamientos sobre puntos gatillo miofasciales (PGM) en pacientes con lesión medular con dolor de hombro crónico (casos) y sin dolor de hombro (controles). Material y método: 16 pacientes con lesión medular (11 varones y 5 mujeres) recibieron cuatro tratamientos, uno por semana, en orden aleatorio, siendo los tratamientos: I) presión, II) vibración [Vib], III) vibración más calor [Vib+C] y IV) vibración más frío [Vib+F]. Las variables dependientes registradas fueron: Wheelchair User's Shoulder Pain Index (WUSPI) y Performance-corrected Wheelchair User's Shoulder Pain Index (PCWUSPI), escala visual analógica (EVA), amplitud de movimiento (AMD) y los umbrales de tolerancia a la presión (TP) que fueron registrados en cinco PGM, incluyendo el infraespinoso lateral (IL), infraespinoso medial (IM), supraespinoso (S), trapecio superior (TS) y el pectoral mayor (PM). Resultados: Los valores de WUSPI, PC-WUSPI y EVA fueron mayores en los casos que en los controles (p<0,05). La AMD de rotación interna fue mayor después de los tratamientos que antes (p<0,05). La Vib+F aumentó TP para el IL. La Vib+C fue el único tratamiento que incrementó TP en los casos (p<0,05) para el S; para el TS el tratamiento de Vib+C aumentó la TP (p<0,05). Conclusión: La terapia combinada resultó más eficaz para aumentar la tolerancia a la presión de la mayoría de los PGM analizados, por lo que podría ser utilizada para tratar el dolor de hombro en lesionados medulares (AU)

Objective: To analyze the acute effects of four treatments for myofascial trigger points (PGM) in spinal cord injury patients with chronic shoulder pain (cases) and without shoulder pain (controls). Material and method: 16 SCI patients (10 men and 6 women) volunteered to participate in the study. Four treatments were applied, once a week, in random order: I) pressure, II) vibration [Vib] III) heat vibration [Vib+C], and IV) cold vibration [Vib+F]. The dependent variables recorded were: Wheelchair User's Shoulder Pain Index (WUSPI) & Performance-corrected Wheelchair User's Shoulder Pain Index (PC-WUSPI), visual analog scale (VAS), range of motion (AMD) and the tolerance thresholds pressure (TP) that were recorded in five PGM, including lateral infraspinatus (IL), infraspinatus medial (IM), supraspinatus (S), upper trapezius (TS) and pectoralis major (PM). Results: WUSPI, PC-WUSPI and EVA values were higher in cases than in controls (p <0.05). AMD internal rotation was greater after treatment than before (P <0.05). The Vib+F increased TP for the IL. The Vib+C was the only treatment that increased TP in cases (p <0.05) for the S; for the TS, the Vib+C treatment increased the TP (p <0.05). Conclusion: Combination therapy was more effective to increase the TP in the majority of the PGM analyzed. In addition, the Vib+F significantly increased the AMD of shoulder internal rotation (AU)

Changes in muscle architecture induced by low load blood flow restricted training.

In order to ascertain whether differing structural mechanisms could underlie blood flow restricted training (BFRT) and high intensity training (HIT), this study had two aims: (i) to gain an insight into the acute variations of muscle architecture following a single bout of two different volumes of BFRT, and (ii) to compare these variations with those observed after HIT. Thirty-five young men volunteered for the study and were randomly divided into three groups: BFRT low volume (BFRT LV), BFRT high volume (BFRT HV) and traditional high intensity resistance training (HIT). All subjects performed a bilateral leg extension exercise session with a load of 20% of one repetition maximum (1RM) in the BFRT groups, whereas the load of the HIT group was equivalent to an 85% of their 1RM. Before and immediately after the exercise bout, ultrasound images were taken from the rectus femoris (RF) and the vastus lateralis (VL). All groups increased their RF (p < 0.001) and VL (p < 0.001) muscle thickness, while the increases in pennation angle were larger in HIT as compared to BFRT LV (p = 0.013) and BFRT HV (p = 0.037). These results support the hypothesis that acute muscle cell swelling may be involved in the processes underlying BFRT induced muscle hypertrophy. Furthermore, our data indicate differing structural responses to exercise between BFRT and HIT.

Muscular adaptations after two different volumes of blood flow-restricted training.

This study aimed to gain an insight into the adaptations of muscle strength and skeletal muscle thickness after two different volumes of blood flow restriction training (BFRT), and compare them with high-intensity training. The sample was divided into four groups: low-volume, low-intensity BFRT (BFRT LV); high-volume, low-intensity BFRT (BFRT HV); traditional high-intensity resistance training (HIT); and a control group, which maintained their routine activities (CON). Leg extension one repetition maximum (1RM), isokinetic peak knee extension, and flexion torques at 60°/s and 180°/s as well as muscle thickness of the rectus femoris (RF) and vastus lateralis (VL) were assessed at baseline and after 5 weeks of training BFRT LV (7.03%, P < 0.05), BFRT HV (6.24%, P < 0.05) and HIT (18.86%, P < 0.001) groups increased 1RM performance, while no changes were observed in the CON group. Muscle thickness of the RF and VL was increased irrespective of the training group (7.5%, P < 0.001; and 9.9%, P < 0.001, respectively). We conclude that doubling the exercise volume with BFRT causes no further benefit with muscular size or strength. Although similar increases in muscle thickness were observed between training groups, HIT increased 1RM performance to a greater extent compared to either volume of BFRT.

Efecto de las vibraciones de cuerpo completo sobre el equilibrio estático y funcional en el accidente cerebrovascular / Effects of whole body vibration on static and functional balance in stroke patients

Objetivo El objetivo de este estudio fue analizar los efectos de un tratamiento rehabilitador con vibraciones de cuerpo completo sobre el equilibrio estático y funcional en pacientes crónicos con accidente cerebrovascular. Material y métodos El estudio prospectivo fue un ensayo clínico controlado. Participaron 22 pacientes que se dividieron en dos grupos: grupo experimental (GE, n = 11), que recibió 17 sesiones de vibraciones a lo largo de 8 semanas, y grupo control (GC, n = 11), que permaneció durante esas 17 sesiones encima de la plataforma, en la misma posición que los sujetos del GE, sin recibir vibraciones. Antes y después de la intervención se realizaron valoraciones del equilibrio mediante el test de Romberg, el test de Tinetti y la escala de Berg. Resultados En los tests de Romberg y de Tinetti no se observaron modificaciones tras la aplicación. Sin embargo, en el test de Tinetti se observó una tendencia a mejorar en el GE. Respecto a la escala de Berg, las personas con hemiparesia en el lado izquierdo mejoraban tras la intervención (p < 0,01), no así las que tenían hemiparesia en el lado derecho (p = 0,420).Conclusiones Las vibraciones de cuerpo completo mejoran el equilibrio funcional en pacientes que han sufrido un accidente cerebrovascular. Pese a que estas mejoras son similares a las encontradas al realizar ejercicio isométrico sin estar éste suplementado con vibraciones, parece que las vibraciones podrían inducir unos beneficios mayores en determinadas valoraciones del equilibrio. El trabajo isométrico en posición de semi-sentadilla mejora el equilibrio funcional en pacientes que han presentado un accidente cerebrovascular. La aplicación de vibraciones de cuerpo completo durante este trabajo isométrico podría resultar beneficiosa en determinadas valoraciones del equilibrio. Los pacientes con hemiparesia en el lado izquierdo parecen beneficiarse en mayor medida de los programas de rehabilitación del equilibrio (AU)

Objective The aim of this study was to analyze the effects of a rehabilitation program with whole body vibration on static and functional balance in chronic stroke patients. Material and methods Twenty-two patients participated. They were divided into two groups: experimental group (EG, n = 11), who received 17 sessions of vibration over 8 weeks and control group (CG, n = 11) who received the same 17 sessions on the platform in the same position as the EG but did not receive vibrations. Balance was assessed before and after intervention using the Romberg test, the Tinetti's test and the Berg balance scale. ResultsChanges were not observed after the intervention with the Romberg and Tinetti's tests. However, the Tinetti's test showed a tendency to improve in the EG. Regarding the Berg's scale, persons with hemiparesis on the left side improved after the intervention (P<.01), but not those with hemiparesis on the right side (P=.420).Conclusions The whole body vibration improves functional balance in patients who have suffered a stroke. Although these improvements are similar to those found in isometric exercise when not complemented with vibration, it seems that the vibrations could induce greater benefits in certain assessments of balance. Isometric work in semi-squat position improves balance function in patients who have suffered a stroke. The application of whole-body vibration during isometric work this could be beneficial in some evaluations of balance. Patients with left-sided hemiparesis seem to benefit more from balance rehabilitation programs (AU)

Effects of whole-body vibration on blood flow and neuromuscular activity in spinal cord injury.

STUDY DESIGN: Crossover trial. OBJECTIVES: To investigate the effects of whole-body vibration (WBV) on muscular activity and blood flow velocity after different vibration treatments in patients with spinal cord injury (SCI). SETTING: Research Center on Physical Disability (Spain). METHODS: Eight individuals with SCI received six 3-min WBV treatments depending on a combination of frequency (10, 20 or 30 Hz) and protocol (constant, that is, three consecutive minutes of WBV, or fragmented, that is, three sets of 1 min of WBV with 1 min of rest between the sets). Femoral artery blood flow velocity was registered at minutes 1, 2 and 3 of WBV, and at minutes 1 and 2 after the end of the stimulus. Electromyography activity (EMG) of vastus lateralis (VL) and vastus medialis (VM) was registered at baseline and during WBV. RESULTS: Peak blood velocity (PBV) increased after 1, 2 and 3 min of WBV. The 10 Hz frequency did not alter blood flow, whereas the 20 Hz frequency increased PBV after 2 and 3 min of WBV, and the 30 Hz frequency increased PBV after 1, 2 and 3 min of WBV and during the first minute after the end of the stimulus. No protocol effect was observed for blood parameters. EMG activity of VL and VM increased independently of the applied frequency or protocol. CONCLUSION: WBV is an effective method to increase leg blood flow and to activate muscle mass in SCI patients, and could be considered to be incorporated in their rehabilitation programs.

Antigonorrhoeal activity of plants used in Guatemala for the treatment of sexually transmitted diseases.

Plants popularly used in Guatemala for the treatment of gonorrhoea were macerated in 50% alcohol and the tincture tested for in vitro activity against Neisseria gonorrhoeae using strains isolated from symptomatic patients and confirmed by standard bacteriological procedures. From 46 plants investigated, 13 (28.3%) showed evident inhibition zones (> 9 mm), seven (15.2%) showed small activity (6.1-8.9 mm) and 26 (56.5%) showed no activity; nine of these plants inhibited five strains of N. gonorrhoea freshly isolated. The most active plants of American origin were: bark of Bixa orellana fruits of Parmentiera edulis, leaf of Diphysa robinioides, Eupatorium odoratum, Gliricidia sepium, Physalis angulata, Piper aduncum and Prosopis juliflora, root of Casimiroa edulis, and whole Clematis dioica.

Evidencia de infección por virus de inmunodeficiencia humana tipo 2 en Cuba: algunas consideraciones epidemiológicas / Evidence of human immunodeficiency virus type II infection in Cuba: some epidemiological considerations

El Virus de Inmunodeficiencia Humana tipo 2 (VIH)-2) fue aislado en 1986 de pacientes con SIDA y personas asintomáticas de Africa Occidental. En nuestro país, entre los meses de agosto-septiembre de 1987 se realizó un primer estudio en busca de portadores de anticuerpos al VIH-2. Se utilizó la prueba de ELISA ELAVIA-II (Pasteur) y para confirmar una prueba de inmunoelectrotransferencia (Western blot) producida por nuestro laboratorio. Se chequearon 129 personas para detectar anticuerpos al VIH-2 (107 cubanos y 22 extranjeros) procedentes de países de Africa (incluyendo de Africa-Occidental), y con otros riesgos, resultando 2 positivos (1 cubano, 1 extranjero). Esto motivó que entre julio de 1988 y marzo de 1989 se chequearan 30.754 personas (8.832 extranjeros, 21.922 cubanos) procedentes de áreas de riesgo, o con otros riesgos epidemiológicos, detectándose 2 extranjeros positivos. En el segundo chequeo se tomaron algunos datos epidemiológicos mediante encuesta-registro, una parte de los cuales se presentan en este trabajo