Progressive inclusion of pearl millet herbage as a supplement for dairy cows fed mixed rations: Effects on methane emissions, dry matter intake, and milk production.

The inclusion of grazing in dairy feeding systems can improve animal welfare and reduce feed costs and labor for animal care and manure management. This work aimed to evaluate the effects of including pearl millet herbage (Pennisetum glaucum 'Campeiro') as a supplement for dairy cows fed total mixed rations (TMR). The treatments included 100% TMR offered ad libitum (control, TMR100), 75% TMR ad libitum intake + access to grazing of a pearl millet pasture between the morning and afternoon milkings (7 h/d; pTMR75), and 50% TMR ad libitum intake + access to grazing of a pearl millet pasture between the morning and afternoon milkings (7 h/d; pTMR50). Nine multiparous Holstein and F1 Jersey × Holstein cows were distributed in a replicated 3 × 3 Latin square design with 3 periods of 21 d (a 16-d adaptation period and a 5-d measurement period). Cows in the TMR75 and TMR50 groups strip-grazed a pearl millet pasture with pre- and postgrazing sward height targets of 60 and 30 cm, respectively. The herbage dry matter intake (DMI) increased with decreasing mixed ration supplies, and the total DMI decreased linearly from 19.0 kg/d in the TMR100 group to 18.0 kg/d in the pTMR50 group. Milk production decreased linearly from 24.0 kg/d in the TMR100 group to 22.4 kg/d in the pTMR50 group, and energy-corrected milk (ECM) production decreased linearly from 26.0 kg/d to 23.6 kg/d. Enteric methane (CH4) emissions decreased linearly from 540 g/d in the TMR100 group to 436 g/d in the pTMR50 group, and CH4 yields (g/kg of DMI) tended to decrease linearly. The CH4 intensity was similar between treatments, averaging 20 g of CH4/kg of ECM. The inclusion of pearl millet herbage in the dairy cow diets decreased the total DMI and milk production to a small extent without affecting CH4 intensity (g/kg of ECM).

Direct detection of Salmonella from poultry samples by DNA isothermal amplification.

1. Salmonellosis is one of the most important diseases in public health and it is usually associated with poultry product consumption. This study aimed to validate rapid methods to detect Salmonella spp. from poultry samples. 2. A DNA isothermal amplification method, previously developed for other matrices, was applied for the specific detection of Salmonella spp. from various samples, including poultry tissues, drag and boot swabs, faeces and feed. A new procedure was validated with Salmonella spp. serotypes and isolates from other enteric bacterial species, as well as naturally contaminated poultry samples. 3. The study demonstrated the successful development and implementation of a procedure, including a DNA isothermal amplification method, for the detection of Salmonella spp. directly from tissues, drag and boot swabs, faeces and feed. The whole procedure can be performed in less than 24 hours and it has been successfully used in a veterinary diagnostic laboratory.

Molecular detection of Salmonella serovars Enteritidis, Heidelberg and Typhimurium directly from pre-enriched poultry samples.

1. Salmonella is one of the most important pathogens in public health and it is usually associated with food-borne diseases. Salmonella serovars Enteritidis and Typhimurium are widespread in the world with outbreaks frequently associated with consumption of poultry products; furthermore, there is an increasing public health concern with the wide dissemination of the serovar Heidelberg in poultry flocks. 2. The aim of the experiment was to develop and to validate rapid methods to detect Salmonella serovars Enteritidis, Typhimurium, and Heidelberg by real-time PCRs and test isolates from pre-enriched poultry samples. 3. Three real-time PCRs were developed and used in combination to detect the serovars Enteritidis, Typhimurium and Heidelberg. These assays were validated by the analysis of 126 Salmonella isolates, eight other enteric bacterial species and 34 naturally contaminated poultry samples after pre-enrichment with buffered peptone water (BPW). 4. Real-time PCRs detected the isolates of the most important poultry serovars (Enteritidis, Typhimurium and Heidelberg) with 100% inclusivity and exclusivity in each assay. The PCR identified monophasic variants of the serovars Typhimurium and Heidelberg. All PCRs were validated in detecting these specific serovars directly from pre-enriched poultry samples. The whole analytical procedure was performed in less than 24 h in a veterinary diagnostic laboratory.

Invasive dynamic electrical impedance myography during 100 s of moderate contraction in rats' gastrocnemius muscle.

GOAL: The present study aimed to investigate the behavior of dynamic electrical impedance myography (dEIM) signals during a 100-s period of the dynamic contraction of Wistar rats' gastrocnemius evoked by electrical stimulation and to link the variations in bioimpedance with muscular energy systems. METHODS: Muscle contraction used 30% of the maximum muscular force and persisted for 100 s, along which dynamic bioimpedance signals were acquired. Based on the bioimpedance signals, two parameters, ΔZc and ΔZpc, were calculated to allow the analysis of their changes with the energy systems that supplied adenosine triphosphate (ATP) to the muscle. ΔZc indicated the variation of impedance of a twitch cycle compared to the values observed during the rest period preceding the cycle, and ΔZpc indicated slow bioimpedance variations compared to the values obtained during the rest period. RESULTS: The results indicated that ΔZc followed the force behavior, achieving a change rate of ∼14%. This parameter was associated with instantaneous impedance changes owing to the occurrence of each twitch. CONCLUSION: Although the findings of this study were linked to energy system processes, future studies are required for improving the understanding of the underlying mechanisms involved in dEIM. SIGNIFICANCE: The results contributed to understanding the relation of energy systems that supply ATP to the muscles with dEIM variations that occurred during muscle activity.

Effect of dietary buriti oil on the quality, fatty acid profile and sensorial attributes of lamb meat.

Forty crossbred (Santa Ines × Dorper) male lambs were used to investigate the effect of dietary buriti oil (BOIL) intake on meat quality, fatty acid (FA) composition and sensory attributes. A completely randomized design with five BOIL intake levels (0, 12, 24, 36 and 48 g/kg DM) was used. Increasing dietary BOIL intake linearly reduced the DMI, slaughter weight, cooking loss, shear force, yellowness, 16:0, c9-18:1 FA concentrations, and the delta-9-desaturase activity index computed using c9-16:1 and 16:0 as product and substrate pair, cis-MUFA and Æ©MUFA/Æ©SFA ratio of lamb meat (P ≤ 0.05); however, increasing dietary BOIL intake quadratically increased the energy intake, lipid content and linearly increased the total FA intake, chroma, collagen, total BI, 18:0, 20:3n-6 concentration and sensory attributes of lamb meat (P ≤ 0.05), without affecting health indexes regarding fat consumption. BOIL addition at levels above 24 g/kg DM in lamb diet reduces growth, however, improves tenderness, flavor and "goat" aroma intensity and slightly changes meat FA levels, promoting better acceptance by panelists.

Development of hybrid microspheres for assessment of multiphase processes.

This work presents a new technique for the synthesis of particles satisfying the conditions of several multiphase suspensions. It consists of manufacturing PMMA_La2O3 hybrid microspheres through suspension polymerization first and then submitting the beads to neutron activation. It was found that the fractional mass of the filler La2O3 in the beads can be greater that 60% using this technique. The results and other properties of the particles clearly indicate that the technique is effective to produce particles for several RPT applications.

Invasive electrical impedance myography at different levels of contraction of gastrocnemius muscle of rat.

Electrical impedance myography (EIM) is as an experimental technique that associates muscle impedance with muscular activity. Changes in muscle impedance during contraction occur mainly due to changes in the morphological and physiological characteristics of muscles that lead to different impeditivities in comparison with the resting condition. There is no consensus on the details of muscular impedance during muscle activity. EIM measurements on humans are also influenced by factors such as the electrode-skin interface, layers of skin and fat, and the connective tissue that can generate undesirable effects in the impedance signal. These effects can be avoided if EIM measurements are carried out directly on the muscle by using the models of animals. This study investigates changes in the EIM signal in the gastrocnemius muscles of Wistar rats during different levels of muscular contraction. In vivo experiments were conducted on 19 male rats. The muscle was exposed, fixed on a load cell, and electrically stimulated to evoke different levels of muscle contraction. Signals of the components of impedance were analyzed against the muscular force signal. The results show moderate correlations (p < 0.05) among the impedance-related parameters of resistance (r = -0.76), reactance (r = 0.57), and phase (r = 0.53). In addition to providing an experimental protocol for the invasive collection of data on electrical impedance to minimize problems associated with surface electrodes, this study shows that of the components of impedance, resistance is most affected by the intensity of muscular contractions and that morphological changes influence impedance mainly at low intensities.

Questionário H-5: um instrumento para o rastreio de crenças limitantes no paciente com hipertensão arterial / H-5 Questionnaire: an instrument for screening limiting beliefs in patients with arterial hypertension

INTRODUÇÃO E/OU FUNDAMENTO: Menos da metade dos pacientes com hipertensão arterial (HA) atinge sua meta terapêutica. A falta de adesão é apontada como a principal causa de resistência ao tratamento. Entre os motivos pelos quais os pacientes não aderem ao plano terapêutico, a falta de letramento em saúde, os mitos e as crenças limitantes (CLs) desempenham papel determinante. Reconhecer e reverter prontamente tais crenças pode ser decisivo para promover a adesão do paciente e o controle pressórico, mas faltam instrumentos que permitam esse rastreio de forma sistemática na prática clínica. MÉTODOS: Elaboramos um Questionário de cinco perguntas (H-5) a partir de análise exploratória das CLs mais frequentemente observadas em ambulatório de referência no tratamento da HA. Cada pergunta do H-5 explora um conjunto de CLs relativas a uma dimensão específica do tratamento anti-hipertensivo. O questionário foi aplicado a 30 pacientes com diagnóstico de HA resistente consecutivamente atendidos em ambulatório público de referência. As perguntas do H-5 são: 1. O que sentimos quando nossa pressão está alta?; 2. Qual o melhor momento para medir a pressão?; 3. Quando podemos parar de tomar o remédio da pressão?; 4. Porque a pressão alta é um problema?; 5. Qual dessas afirmações é verdadeira sobre o estilo de vida? O formato de avaliação foi por respostas fechadas de múltipla escolha, sendo oferecidas 4 opções por pergunta. RESULTADOS: O H-5 foi aplicado na sala de espera antes da consulta, com tempo médio de execução de 6 minutos. A idade média dos pacientes foi 63,9 ± 9,2 anos (sexo feminino: 83%: IMC: 33,1 ± 6,1). N de anti-hipertensivos: 3,9 ± 1,6; PAS media de consultório: 137 ± 17,4 mmHg); escolaridade: 80% apenas ensino fundamental. A Nota Média foi de 3 acertos em 5 (0= 5%; 2= 20%; 3= 50%; 4= 15%; 5=20%) A taxa de acertos por pergunta (P) foi respectivamente: P1= 20%; P2= 20%; P3= 95%; P4= 80%; P5=85%. Apenas 1 a cada 5 pacientes com HA resistente demonstrou saber que a HA é uma condição assintomática ou que a pressão arterial deve ser medida em condições controladas. CONCLUSÕES: A aplicação do Questionário H-5 foi simples e de rápida execução. 80% dos pacientes apresentou algum grau de crenças limitantes em relação ao tratamento da HA.

A jornada ideal do paciente com hiperaldosteronismo primário: proposta de algoritmo a partir da revisão sistemática das diretrizes vigentes / The ideal journey of patients with primary hyperaldosteronism: algorithm proposal based on a systematic review of current guidelines

INTRODUÇÃO E/OU FUNDAMENTO: O Hiperaldosteronismo Primário (HP) é a principal causa de hipertensão arterial (HA) endócrina e estima-se que até 20% dos hipertensos resistentes possa ser portador da condição. Indivíduos com HP apresentam um risco cardiovascular (CV) de 4 a 12 vezes mais elevado que portadores de HA primária. Apesar disso, o HP continua largamente subdiagnosticado, em parte pela falta de padronização de triagem, diagnóstico e tratamento. MÉTODOS: A partir de processo de revisão sistemática das diretrizes nacionais e internacionais de HA e HP, elaboramos um algoritmo ilustrando a Jornada Ideal do Paciente com HP. A busca foi realizada em idioma português e inglês na base MEDLINE/PubMed. Selecionamos as publicações dos últimos 5 anos. O processo foi conduzido simultaneamente por dois pesquisadores e os resultados confrontados. RESULTADOS: Um total de 3.476 artigos foram triados para HA e 1.238 para HP. Após revisão e confrontação foram incluídas 22 diretrizes de HA e 9 diretrizes de HP. A partir da análise dos documentos selecionados a Jornada Ideal do Paciente com HP foi segmentada em 7 etapas: 1-Suspeita (definidas as Red Flags); 2-Rastreio (Concentração Plasmática de Aldosterona e Renina ou Atividade da Renina Plasmática); 3-Diagnóstico Laboratorial (critérios e testes confirmatórios); 4-Diagnóstico Anatômico (exames de imagem); 5-Tratamento Cirúrgico (critérios de encaminhamento); 6-Tratamento Clínico (metas terapêuticas e ajuste posológico); 7-Seguimento (critérios e prazos de reavaliação periódica). Com o intuito de acelerar a jornada do paciente, para cada etapa foram definidos gatilhos e ações esperadas, assim como prazos ideais e prazos razoáveis. CONCLUSÕES: Com base nas melhores evidências atualmente disponíveis e a partir de revisão sistemática das diretrizes vigentes, apresentamos uma proposta de Jornada Ideal do Paciente com HP, como modelo para a implantação de serviços especializados para o rastreio, o diagnóstico, o tratamento e o follow-up do HA.

Lactate threshold by muscle electrical impedance in professional rowers.

Lactate threshold (LT) is one of the physiological parameters usually used in rowing sport training prescription because it indicates the transitions from aerobic to anaerobic metabolism. Assessment of LT is classically based on a series of values of blood lactate concentrations obtained during progressive exercise tests and thus has an invasive aspect. The feasibility of noninvasive LT estimative through bioelectrical impedance spectroscopy (BIS) data collected in thigh muscles during rowing ergometer exercise tests was investigated. Nineteen professional rowers, age 19 (mean) ± 4.8 (standard deviation) yr, height 187.3 ± 6.6 cm, body mass 83 ± 7.7 kg, and training experience of 7 ± 4 yr, were evaluated in a rowing ergometer progressive test with paired measures of blood lactate concentration and BIS in thigh muscles. Bioelectrical impedance data were obtained by using a bipolar method of spectroscopy based on the current response to a voltage step. An electrical model was used to interpret BIS data and to derive parameters that were investigated to estimate LT noninvasively. From the serial blood lactate measurements, LT was also determined through Dmax method (LTDmax). The zero crossing of the second derivative of kinetic of the capacitance electrode (Ce), one of the BIS parameters, was used to estimate LT. The agreement between the LT estimates through BIS (LTBIS) and through Dmax method (LTDmax) was evaluated using Bland-Altman plots, leading to a mean difference between the estimates of just 0.07 W and a Pearson correlation coefficient r = 0.85. This result supports the utilization of the proposed method based on BIS parameters for estimating noninvasively the lactate threshold in rowing.

Direct Detection and Quantification of Bacterial Pathogens from Broiler Cecal Samples in the Slaughter Line by Real-Time PCR

Chicken meat is an important source of foodborne pathogens, including Salmonella, Campylobacter, and Clostridium perfringens. These bacteria can occur in the intestinal microbiota of broilers and contaminate chicken carcasses in industrial meat processing. This study aimed to develop and evaluate a procedure based on real-time PCRs for the direct detection and quantification of these three bacteria in broilers' ceca collected in poultry slaughter houses and demonstrate the occurrence of these important foodborne pathogens in Brazilian poultry production flocks. Cecal contents were collected from 45 different broiler flocks in three different slaughterhouses in the state of Paraná, Brazil, totaling 45 samples (in pools of 10 different ceca/chickens per broiler flock). Then, these samples were tested for the detection and quantification of Salmonella, Campylobacter, and Clostridium perfringens by real-time PCRs. The results demonstrated the occurrence of three (6.7%) positive pools for Salmonella, 20 (44.4%) for Campylobacter, and 32 (71.1%) for C. perfringens. Mean bacterial concentrations in the positive samples were 4.3log10 cells/g for Salmonella, 6.4 log10 cells/g for Campylobacter, and 5.5 log10 cells/g for C. perfringens. In conclusion, Salmonella, Campylobacter, and C. perfringens could be detected and quantified directly from the broilers cecal contents collected in the slaughter line. This procedure will be certainly useful to more quickly detect these foodborne pathogens and prevent their occurrence in chicken meat and other poultry food products.(AU)

Detection of questionable occlusal carious lesions using an electrical bioimpedance method with fractional electrical model.

This in vitro study evaluated the diagnostic performance of an alternative electric bioimpedance spectroscopy technique (BIS-STEP) detect questionable occlusal carious lesions. Six specialists carried out the visual (V), radiography (R), and combined (VR) exams of 57 sound or non-cavitated occlusal carious lesion teeth classifying the occlusal surfaces in sound surface (H), enamel caries (EC), and dentinal caries (DC). Measurements were based on the current response to a step voltage excitation (BIS-STEP). A fractional electrical model was used to predict the current response in the time domain and to estimate the model parameters: Rs and Rp (resistive parameters), and C and α (fractional parameters). Histological analysis showed caries prevalence of 33.3% being 15.8% hidden caries. Combined examination obtained the best traditional diagnostic results with specificity = 59.0%, sensitivity = 70.9%, and accuracy = 60.8%. There were statistically significant differences in bioimpedance parameters between the H and EC groups (p = 0.016) and between the H and DC groups (Rs, p = 0.006; Rp, p = 0.022, and α, p = 0.041). Using a suitable threshold for the Rs, we obtained specificity = 60.7%, sensitivity = 77.9%, accuracy = 73.2%, and 100% of detection for deep lesions. It can be concluded that BIS-STEP method could be an important tool to improve the detection and management of occlusal non-cavitated primary caries and pigmented sites.

Bioelectrical impedance spectroscopy for the assessment of body fluid volumes of term neonates.

The assessment of fluid volume in neonates by a noninvasive, inexpensive, and fast method can contribute significantly to increase the quality of neonatal care. The objective of the present study was to calibrate an acquisition system and software to estimate the bioelectrical impedance parameters obtained by a method of bioelectrical impedance spectroscopy based on step response and to develop specific equations for the neonatal population to determine body fluid compartments. Bioelectric impedance measurements were performed by a laboratory homemade instrument. The volumes were estimated in a clinical study on 30 full-term neonates at four different times during the first month of life. During the first 24 hours of life the total body water, extracellular water and intracellular water were 2.09 +/- 0.25, 1.20 +/- 0.19, and 0.90 +/- 0.25 liters, respectively. By the 48th hour they were 1.87 +/- 0.27, 1.08 +/- 0.17, and 0.79 +/- 0.21 liters, respectively. On the 10th day they were 2.02 +/- 0.25, 1.29 +/- 0.21, and 0.72 +/- 0.14 liters, respectively, and after 1 month they were 2.34 +/- 0.27, 1.62 +/- 0.20, and 0.72 +/- 0.13 liters, respectively. The behavior of the estimated volume was correlated with neonatal body weight changes, leading to a better interpretation of such changes. In conclusion, this study indicates the feasibility of bioelectrical impedance spectroscopy as a method to help fluid administration in intensive care neonatal units, and also contribute to the development of new equations to estimate neonatal body fluid contents.

A method for bio-electrical impedance analysis based on a step-voltage response.

Bioimpedance analysis (BIA) has been researched broadly, since it is simple, it presents good results and the analysers are portable, allowing it to be used in field studies. This paper presents a new technique of BIA based on a step-voltage current response and bipolar electrode array. A prototype of this new kind of analyser was developed and constructed to test the technique. Bench tests were performed to calibrate the prototype and the obtained results were comparable to those of commercial analysers. Body composition tests were conducted on 67 subjects of both sexes. Besides the bioimpedance analysis, anthropometric measures, consisting of weight, height, circumference and skinfold thickness, were also obtained from the subjects to allow an estimation of the body composition from anthropometric equations established in the literature. The results point to a good correlation (Pearson coefficient, r = 0.9645) between the anthropometric estimated fat-free mass (FFM) and its analogue estimated by the new bioimpedance technique.

Determination of radial artery compliance can increase the diagnostic power of pulse wave velocity measurement.

Pulse wave velocity (PWV) is an indicator associated with the arterial stiffness. Although this technique has been used in the diagnosis of systemic arterial hypertension (SAH), it cannot supply alone enough information about the pathogenesis of this disturbance. This paper aims to determine the compliance of brachial-radial arterial segment by applying a three-element windkessel model, and by using the same pressure waveforms acquired to calculate the PWV. The proposed method to determine the arterial compliance was evaluated with a physical simulation of the arterial system, where parameters were known, resulting in an estimation error of 0.73 x 10(-7) cm5 dyne(-1). In a clinical study the estimated compliance was statistically different (p < 0.01) in a controlled group ((3.12 +/- 3.53) x 10(-7) cm5 dyne(-1)) and in an SAH group ((1.04 +/- 0.74) x 10(-7) cm5 dyne(-1)). It was observed that the PWV value calculated using the maximum of the first derivative of the pressure waveform upstroke as characteristic points was the best correlated (r = -0.71) with the determined compliance. Because SAH normally results, among other causes. from a decreased arterial compliance the results suggest that the determined compliance could be used concomitantly with PWV to supply more diagnostic information about the pathogenesis of SAH.

Comparison of two bioimpedance spectroscopy techniques in the assessment of body fluid volumes.

The present study aimed to compare the estimates of body liquid volumes performed by two bioimpedance spectrometry techniques. One based on a step response technique (BIS-PEB) and second one based on multifrequency Xitron Hydra 4200 equipment (Xitron Technologies, San Diego, CA, USA). The convenience sample was initially composed of 422 students from a military parachuting course of the Brazilian Army. From such sample 42 male students were randomly selected to be evaluated during three weeks. The anthropometrical characteristics of the sample can be summarized as: 25.18 +/- 4.10 years old; weight equals of 76.77 +/- 7.84 kg; height equals to 174.96 +/- 5.67 cm; body mass index (BMI) equal to 25.05 +/- 2.11 kg m(-2). Bland-Altman graphics were used to compare the two methods in what concerns to estimate of extracellular fluid (ECF), intracellular fluid (ICF), and total body water (TBW). One can observe that the estimates of the two techniques present a good correlation, especially in the case of ECF (r = 0.975). The present study indicates that BIS-PEB technique associated with De Lorenzo equation can supply noninvasive estimates of body fluid volumes comparable to Xitron Hydra 4200 equipment.

Objective assessment of knee osteroarthritis in parachuters by bioimpedance spectroscopy.

The aim of the present study was to derive an objective and noninvasive assessment of osteoarthritis of the knee joint by bioimpedance spectrocopy (BIS). The study was performed in Brazilian Military Parachuters and intends to contribute to the improvement of the early diagnosis of joint degeneration. Twelve male volunteers (24 knee joints) participated in the study. A novel index (ID) to assess the disease was proposed from the raw bioimpedance parameter. This index was compared with a subjective rating (Dejour scale) performed by 3 therapists. The results indicated that the values of ID were significantly different (p0.001) between the control group (class 1 of Dejour) and the pathological group (class 2 or higher). A Spearman correlation of -0.81 between the values of ID and the therapists rating was detected. Despite the need of increasing the sample size, the novel technique seems to be capable of supplying an objective and non-invasive tool for helping the diagnosis of the knee osteoarthritis.

A programmable system of functional electrical stimulation (FES).

The development of a novel system intended to perform functional electrical stimulation (FES) is presented. A virtual instrument developed in Labview communicates with a PC through USB and controls the hardware compound of analog and digital circuits. The block diagram of the hardware and the main characteristics of the virtual instrument are presented, as well the results of the electrical safety tests and the errors associated to the programmed and real values of the amplitude, pulse width and frequency of the output current. The results point the equipment can be used in the therapy of paraplegic patients maintaining safety limits reported in the literature.

Estimation of the lactate threshold using bioelectrical impedance spectroscopy: a new noninvasive method.

Bioelectrical Impedance Spectroscopy (BIS) is a noninvasive technology with potential application to study exercise physiology as body composition and estimation of maximal oxygen uptake. The aim of the study was to compare the power at lactate threshold (WLT) obtained using blood lactate concentration (BLC) with the power at lactate threshold from BIS (WBT). Fifty physical education students, 35 men and 15 women (age: 24.1 +/- 5.5 years; height: 168.6 +/- 24.6 cm; weight: 70.1 +/- 9.8 kg), undergoing incremental cycle ergometer test (ICET) have participated of the study. Significant correlations (p<0.05) for Pearson coefficient were found between the two methods (r = 0.96) and standard error of estimate (SEE)=5.6 W. The mean value showed 66.7+/- 20.3 W and 66.7+/- 21.1 W between the invasive technique (WLT) and noninvasive technique (WBT), respectively. The results of this study suggest that BIS, when applied with the ICET, is a valid method to estimate the power at LT.